includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use Wikimedia\Rdbms\Database;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use MediaWiki\Linker\LinkTarget;
  28 use MediaWiki\Interwiki\InterwikiLookup;
  29 use MediaWiki\MediaWikiServices;
  30
  31 /**
  32  * Represents a title within MediaWiki.
  33  * Optionally may contain an interwiki designation or namespace.
  34  * @note This class can fetch various kinds of data from the database;
  35  *       however, it does so inefficiently.
  36  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  37  *       and does not rely on global state or the database.
  38  */
  39 class Title implements LinkTarget, IDBAccessObject {
  40         /** @var MapCacheLRU|null */
  41         private static $titleCache = null;
  42
  43         /**
  44          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  45          * commonly used titles. On a batch operation this can become a memory leak
  46          * if not bounded. After hitting this many titles reset the cache.
  47          */
  48         const CACHE_MAX = 1000;
  49
  50         /**
  51          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  52          * to use the master DB
  53          */
  54         const GAID_FOR_UPDATE = 1;
  55
  56         /**
  57          * @name Private member variables
  58          * Please use the accessor functions instead.
  59          * @private
  60          */
  61         // @{
  62
  63         /** @var string Text form (spaces not underscores) of the main part */
  64         public $mTextform = '';
  65
  66         /** @var string URL-encoded form of the main part */
  67         public $mUrlform = '';
  68
  69         /** @var string Main part with underscores */
  70         public $mDbkeyform = '';
  71
  72         /** @var string Database key with the initial letter in the case specified by the user */
  73         protected $mUserCaseDBKey;
  74
  75         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  76         public $mNamespace = NS_MAIN;
  77
  78         /** @var string Interwiki prefix */
  79         public $mInterwiki = '';
  80
  81         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  82         private $mLocalInterwiki = false;
  83
  84         /** @var string Title fragment (i.e. the bit after the #) */
  85         public $mFragment = '';
  86
  87         /** @var int Article ID, fetched from the link cache on demand */
  88         public $mArticleID = -1;
  89
  90         /** @var bool|int ID of most recent revision */
  91         protected $mLatestID = false;
  92
  93         /**
  94          * @var bool|string ID of the page's content model, i.e. one of the
  95          *   CONTENT_MODEL_XXX constants
  96          */
  97         private $mContentModel = false;
  98
  99         /**
 100          * @var bool If a content model was forced via setContentModel()
 101          *   this will be true to avoid having other code paths reset it
 102          */
 103         private $mForcedContentModel = false;
 104
 105         /** @var int Estimated number of revisions; null of not loaded */
 106         private $mEstimateRevisions;
 107
 108         /** @var array Array of groups allowed to edit this article */
 109         public $mRestrictions = [];
 110
 111         /**
 112          * @var string|bool Comma-separated set of permission keys
 113          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
 114          * Edit and move sections are separated by a colon
 115          * Example: "edit=autoconfirmed,sysop:move=sysop"
 116          */
 117         protected $mOldRestrictions = false;
 118
 119         /** @var bool Cascade restrictions on this page to included templates and images? */
 120         public $mCascadeRestriction;
 121
 122         /** Caching the results of getCascadeProtectionSources */
 123         public $mCascadingRestrictions;
 124
 125         /** @var array When do the restrictions on this page expire? */
 126         protected $mRestrictionsExpiry = [];
 127
 128         /** @var bool Are cascading restrictions in effect on this page? */
 129         protected $mHasCascadingRestrictions;
 130
 131         /** @var array Where are the cascading restrictions coming from on this page? */
 132         public $mCascadeSources;
 133
 134         /** @var bool Boolean for initialisation on demand */
 135         public $mRestrictionsLoaded = false;
 136
 137         /**
 138          * Text form including namespace/interwiki, initialised on demand
 139          *
 140          * Only public to share cache with TitleFormatter
 141          *
 142          * @private
 143          * @var string|null
 144          */
 145         public $prefixedText = null;
 146
 147         /** @var mixed Cached value for getTitleProtection (create protection) */
 148         public $mTitleProtection;
 149
 150         /**
 151          * @var int Namespace index when there is no namespace. Don't change the
 152          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 153          *   Zero except in {{transclusion}} tags.
 154          */
 155         public $mDefaultNamespace = NS_MAIN;
 156
 157         /** @var int The page length, 0 for special pages */
 158         protected $mLength = -1;
 159
 160         /** @var null Is the article at this title a redirect? */
 161         public $mRedirect = null;
 162
 163         /** @var array Associative array of user ID -> timestamp/false */
 164         private $mNotificationTimestamp = [];
 165
 166         /** @var bool Whether a page has any subpages */
 167         private $mHasSubpages;
 168
 169         /** @var bool The (string) language code of the page's language and content code. */
 170         private $mPageLanguage = false;
 171
 172         /** @var string|bool|null The page language code from the database, null if not saved in
 173          * the database or false if not loaded, yet. */
 174         private $mDbPageLanguage = false;
 175
 176         /** @var TitleValue|null A corresponding TitleValue object */
 177         private $mTitleValue = null;
 178
 179         /** @var bool|null Would deleting this page be a big deletion? */
 180         private $mIsBigDeletion = null;
 181         // @}
 182
 183         /**
 184          * B/C kludge: provide a TitleParser for use by Title.
 185          * Ideally, Title would have no methods that need this.
 186          * Avoid usage of this singleton by using TitleValue
 187          * and the associated services when possible.
 188          *
 189          * @return TitleFormatter
 190          */
 191         private static function getTitleFormatter() {
 192                 return MediaWikiServices::getInstance()->getTitleFormatter();
 193         }
 194
 195         /**
 196          * B/C kludge: provide an InterwikiLookup for use by Title.
 197          * Ideally, Title would have no methods that need this.
 198          * Avoid usage of this singleton by using TitleValue
 199          * and the associated services when possible.
 200          *
 201          * @return InterwikiLookup
 202          */
 203         private static function getInterwikiLookup() {
 204                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 205         }
 206
 207         /**
 208          * @protected
 209          */
 210         function __construct() {
 211         }
 212
 213         /**
 214          * Create a new Title from a prefixed DB key
 215          *
 216          * @param string $key The database key, which has underscores
 217          *      instead of spaces, possibly including namespace and
 218          *      interwiki prefixes
 219          * @return Title|null Title, or null on an error
 220          */
 221         public static function newFromDBkey( $key ) {
 222                 $t = new self();
 223                 $t->mDbkeyform = $key;
 224
 225                 try {
 226                         $t->secureAndSplit();
 227                         return $t;
 228                 } catch ( MalformedTitleException $ex ) {
 229                         return null;
 230                 }
 231         }
 232
 233         /**
 234          * Create a new Title from a TitleValue
 235          *
 236          * @param TitleValue $titleValue Assumed to be safe.
 237          *
 238          * @return Title
 239          */
 240         public static function newFromTitleValue( TitleValue $titleValue ) {
 241                 return self::newFromLinkTarget( $titleValue );
 242         }
 243
 244         /**
 245          * Create a new Title from a LinkTarget
 246          *
 247          * @param LinkTarget $linkTarget Assumed to be safe.
 248          *
 249          * @return Title
 250          */
 251         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 252                 if ( $linkTarget instanceof Title ) {
 253                         // Special case if it's already a Title object
 254                         return $linkTarget;
 255                 }
 256                 return self::makeTitle(
 257                         $linkTarget->getNamespace(),
 258                         $linkTarget->getText(),
 259                         $linkTarget->getFragment(),
 260                         $linkTarget->getInterwiki()
 261                 );
 262         }
 263
 264         /**
 265          * Create a new Title from text, such as what one would find in a link. De-
 266          * codes any HTML entities in the text.
 267          *
 268          * Title objects returned by this method are guaranteed to be valid, and
 269          * thus return true from the isValid() method.
 270          *
 271          * @param string|int|null $text The link text; spaces, prefixes, and an
 272          *   initial ':' indicating the main namespace are accepted.
 273          * @param int $defaultNamespace The namespace to use if none is specified
 274          *   by a prefix.  If you want to force a specific namespace even if
 275          *   $text might begin with a namespace prefix, use makeTitle() or
 276          *   makeTitleSafe().
 277          * @throws InvalidArgumentException
 278          * @return Title|null Title or null on an error.
 279          */
 280         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 281                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 282                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 283                         throw new InvalidArgumentException( '$text must be a string.' );
 284                 }
 285                 if ( $text === null ) {
 286                         return null;
 287                 }
 288
 289                 try {
 290                         return self::newFromTextThrow( (string)$text, $defaultNamespace );
 291                 } catch ( MalformedTitleException $ex ) {
 292                         return null;
 293                 }
 294         }
 295
 296         /**
 297          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 298          * rather than returning null.
 299          *
 300          * The exception subclasses encode detailed information about why the title is invalid.
 301          *
 302          * Title objects returned by this method are guaranteed to be valid, and
 303          * thus return true from the isValid() method.
 304          *
 305          * @see Title::newFromText
 306          *
 307          * @since 1.25
 308          * @param string $text Title text to check
 309          * @param int $defaultNamespace
 310          * @throws MalformedTitleException If the title is invalid
 311          * @return Title
 312          */
 313         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 314                 if ( is_object( $text ) ) {
 315                         throw new MWException( '$text must be a string, given an object' );
 316                 } elseif ( $text === null ) {
 317                         // Legacy code relies on MalformedTitleException being thrown in this case
 318                         // (happens when URL with no title in it is parsed). TODO fix
 319                         throw new MalformedTitleException( 'title-invalid-empty' );
 320                 }
 321
 322                 $titleCache = self::getTitleCache();
 323
 324                 // Wiki pages often contain multiple links to the same page.
 325                 // Title normalization and parsing can become expensive on pages with many
 326                 // links, so we can save a little time by caching them.
 327                 // In theory these are value objects and won't get changed...
 328                 if ( $defaultNamespace == NS_MAIN ) {
 329                         $t = $titleCache->get( $text );
 330                         if ( $t ) {
 331                                 return $t;
 332                         }
 333                 }
 334
 335                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 336                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 337
 338                 $t = new Title();
 339                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 340                 $t->mDefaultNamespace = (int)$defaultNamespace;
 341
 342                 $t->secureAndSplit();
 343                 if ( $defaultNamespace == NS_MAIN ) {
 344                         $titleCache->set( $text, $t );
 345                 }
 346                 return $t;
 347         }
 348
 349         /**
 350          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 351          *
 352          * Example of wrong and broken code:
 353          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 354          *
 355          * Example of right code:
 356          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 357          *
 358          * Create a new Title from URL-encoded text. Ensures that
 359          * the given title's length does not exceed the maximum.
 360          *
 361          * @param string $url The title, as might be taken from a URL
 362          * @return Title|null The new object, or null on an error
 363          */
 364         public static function newFromURL( $url ) {
 365                 $t = new Title();
 366
 367                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 368                 # but some URLs used it as a space replacement and they still come
 369                 # from some external search tools.
 370                 if ( strpos( self::legalChars(), '+' ) === false ) {
 371                         $url = strtr( $url, '+', ' ' );
 372                 }
 373
 374                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 375
 376                 try {
 377                         $t->secureAndSplit();
 378                         return $t;
 379                 } catch ( MalformedTitleException $ex ) {
 380                         return null;
 381                 }
 382         }
 383
 384         /**
 385          * @return MapCacheLRU
 386          */
 387         private static function getTitleCache() {
 388                 if ( self::$titleCache === null ) {
 389                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 390                 }
 391                 return self::$titleCache;
 392         }
 393
 394         /**
 395          * Returns a list of fields that are to be selected for initializing Title
 396          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 397          * whether to include page_content_model.
 398          *
 399          * @return array
 400          */
 401         protected static function getSelectFields() {
 402                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 403
 404                 $fields = [
 405                         'page_namespace', 'page_title', 'page_id',
 406                         'page_len', 'page_is_redirect', 'page_latest',
 407                 ];
 408
 409                 if ( $wgContentHandlerUseDB ) {
 410                         $fields[] = 'page_content_model';
 411                 }
 412
 413                 if ( $wgPageLanguageUseDB ) {
 414                         $fields[] = 'page_lang';
 415                 }
 416
 417                 return $fields;
 418         }
 419
 420         /**
 421          * Create a new Title from an article ID
 422          *
 423          * @param int $id The page_id corresponding to the Title to create
 424          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 425          * @return Title|null The new object, or null on an error
 426          */
 427         public static function newFromID( $id, $flags = 0 ) {
 428                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 429                 $row = $db->selectRow(
 430                         'page',
 431                         self::getSelectFields(),
 432                         [ 'page_id' => $id ],
 433                         __METHOD__
 434                 );
 435                 if ( $row !== false ) {
 436                         $title = self::newFromRow( $row );
 437                 } else {
 438                         $title = null;
 439                 }
 440
 441                 return $title;
 442         }
 443
 444         /**
 445          * Make an array of titles from an array of IDs
 446          *
 447          * @param int[] $ids Array of IDs
 448          * @return Title[] Array of Titles
 449          */
 450         public static function newFromIDs( $ids ) {
 451                 if ( !count( $ids ) ) {
 452                         return [];
 453                 }
 454                 $dbr = wfGetDB( DB_REPLICA );
 455
 456                 $res = $dbr->select(
 457                         'page',
 458                         self::getSelectFields(),
 459                         [ 'page_id' => $ids ],
 460                         __METHOD__
 461                 );
 462
 463                 $titles = [];
 464                 foreach ( $res as $row ) {
 465                         $titles[] = self::newFromRow( $row );
 466                 }
 467                 return $titles;
 468         }
 469
 470         /**
 471          * Make a Title object from a DB row
 472          *
 473          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 474          * @return Title Corresponding Title
 475          */
 476         public static function newFromRow( $row ) {
 477                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 478                 $t->loadFromRow( $row );
 479                 return $t;
 480         }
 481
 482         /**
 483          * Load Title object fields from a DB row.
 484          * If false is given, the title will be treated as non-existing.
 485          *
 486          * @param stdClass|bool $row Database row
 487          */
 488         public function loadFromRow( $row ) {
 489                 if ( $row ) { // page found
 490                         if ( isset( $row->page_id ) ) {
 491                                 $this->mArticleID = (int)$row->page_id;
 492                         }
 493                         if ( isset( $row->page_len ) ) {
 494                                 $this->mLength = (int)$row->page_len;
 495                         }
 496                         if ( isset( $row->page_is_redirect ) ) {
 497                                 $this->mRedirect = (bool)$row->page_is_redirect;
 498                         }
 499                         if ( isset( $row->page_latest ) ) {
 500                                 $this->mLatestID = (int)$row->page_latest;
 501                         }
 502                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 503                                 $this->mContentModel = (string)$row->page_content_model;
 504                         } elseif ( !$this->mForcedContentModel ) {
 505                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 506                         }
 507                         if ( isset( $row->page_lang ) ) {
 508                                 $this->mDbPageLanguage = (string)$row->page_lang;
 509                         }
 510                         if ( isset( $row->page_restrictions ) ) {
 511                                 $this->mOldRestrictions = $row->page_restrictions;
 512                         }
 513                 } else { // page not found
 514                         $this->mArticleID = 0;
 515                         $this->mLength = 0;
 516                         $this->mRedirect = false;
 517                         $this->mLatestID = 0;
 518                         if ( !$this->mForcedContentModel ) {
 519                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 520                         }
 521                 }
 522         }
 523
 524         /**
 525          * Create a new Title from a namespace index and a DB key.
 526          *
 527          * It's assumed that $ns and $title are safe, for instance when
 528          * they came directly from the database or a special page name,
 529          * not from user input.
 530          *
 531          * No validation is applied. For convenience, spaces are normalized
 532          * to underscores, so that e.g. user_text fields can be used directly.
 533          *
 534          * @note This method may return Title objects that are "invalid"
 535          * according to the isValid() method. This is usually caused by
 536          * configuration changes: e.g. a namespace that was once defined is
 537          * no longer configured, or a character that was once allowed in
 538          * titles is now forbidden.
 539          *
 540          * @param int $ns The namespace of the article
 541          * @param string $title The unprefixed database key form
 542          * @param string $fragment The link fragment (after the "#")
 543          * @param string $interwiki The interwiki prefix
 544          * @return Title The new object
 545          */
 546         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 547                 $t = new Title();
 548                 $t->mInterwiki = $interwiki;
 549                 $t->mFragment = $fragment;
 550                 $t->mNamespace = $ns = (int)$ns;
 551                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 552                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 553                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 554                 $t->mTextform = strtr( $title, '_', ' ' );
 555                 $t->mContentModel = false; # initialized lazily in getContentModel()
 556                 return $t;
 557         }
 558
 559         /**
 560          * Create a new Title from a namespace index and a DB key.
 561          * The parameters will be checked for validity, which is a bit slower
 562          * than makeTitle() but safer for user-provided data.
 563          *
 564          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 565          * that is, they return true from the isValid() method. If no valid Title
 566          * can be constructed from the input, this method returns null.
 567          *
 568          * @param int $ns The namespace of the article
 569          * @param string $title Database key form
 570          * @param string $fragment The link fragment (after the "#")
 571          * @param string $interwiki Interwiki prefix
 572          * @return Title|null The new object, or null on an error
 573          */
 574         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 575                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 576                 // but presently, that means more overhead on a potential performance hotspot.
 577
 578                 if ( !MWNamespace::exists( $ns ) ) {
 579                         return null;
 580                 }
 581
 582                 $t = new Title();
 583                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 584
 585                 try {
 586                         $t->secureAndSplit();
 587                         return $t;
 588                 } catch ( MalformedTitleException $ex ) {
 589                         return null;
 590                 }
 591         }
 592
 593         /**
 594          * Create a new Title for the Main Page
 595          *
 596          * @return Title The new object
 597          */
 598         public static function newMainPage() {
 599                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 600                 // Don't give fatal errors if the message is broken
 601                 if ( !$title ) {
 602                         $title = self::newFromText( 'Main Page' );
 603                 }
 604                 return $title;
 605         }
 606
 607         /**
 608          * Get the prefixed DB key associated with an ID
 609          *
 610          * @param int $id The page_id of the article
 611          * @return Title|null An object representing the article, or null if no such article was found
 612          */
 613         public static function nameOf( $id ) {
 614                 $dbr = wfGetDB( DB_REPLICA );
 615
 616                 $s = $dbr->selectRow(
 617                         'page',
 618                         [ 'page_namespace', 'page_title' ],
 619                         [ 'page_id' => $id ],
 620                         __METHOD__
 621                 );
 622                 if ( $s === false ) {
 623                         return null;
 624                 }
 625
 626                 $n = self::makeName( $s->page_namespace, $s->page_title );
 627                 return $n;
 628         }
 629
 630         /**
 631          * Get a regex character class describing the legal characters in a link
 632          *
 633          * @return string The list of characters, not delimited
 634          */
 635         public static function legalChars() {
 636                 global $wgLegalTitleChars;
 637                 return $wgLegalTitleChars;
 638         }
 639
 640         /**
 641          * Utility method for converting a character sequence from bytes to Unicode.
 642          *
 643          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 644          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 645          *
 646          * @param string $byteClass
 647          * @return string
 648          */
 649         public static function convertByteClassToUnicodeClass( $byteClass ) {
 650                 $length = strlen( $byteClass );
 651                 // Input token queue
 652                 $x0 = $x1 = $x2 = '';
 653                 // Decoded queue
 654                 $d0 = $d1 = $d2 = '';
 655                 // Decoded integer codepoints
 656                 $ord0 = $ord1 = $ord2 = 0;
 657                 // Re-encoded queue
 658                 $r0 = $r1 = $r2 = '';
 659                 // Output
 660                 $out = '';
 661                 // Flags
 662                 $allowUnicode = false;
 663                 for ( $pos = 0; $pos < $length; $pos++ ) {
 664                         // Shift the queues down
 665                         $x2 = $x1;
 666                         $x1 = $x0;
 667                         $d2 = $d1;
 668                         $d1 = $d0;
 669                         $ord2 = $ord1;
 670                         $ord1 = $ord0;
 671                         $r2 = $r1;
 672                         $r1 = $r0;
 673                         // Load the current input token and decoded values
 674                         $inChar = $byteClass[$pos];
 675                         if ( $inChar == '\\' ) {
 676                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 677                                         $x0 = $inChar . $m[0];
 678                                         $d0 = chr( hexdec( $m[1] ) );
 679                                         $pos += strlen( $m[0] );
 680                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 681                                         $x0 = $inChar . $m[0];
 682                                         $d0 = chr( octdec( $m[0] ) );
 683                                         $pos += strlen( $m[0] );
 684                                 } elseif ( $pos + 1 >= $length ) {
 685                                         $x0 = $d0 = '\\';
 686                                 } else {
 687                                         $d0 = $byteClass[$pos + 1];
 688                                         $x0 = $inChar . $d0;
 689                                         $pos += 1;
 690                                 }
 691                         } else {
 692                                 $x0 = $d0 = $inChar;
 693                         }
 694                         $ord0 = ord( $d0 );
 695                         // Load the current re-encoded value
 696                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 697                                 $r0 = sprintf( '\x%02x', $ord0 );
 698                         } elseif ( $ord0 >= 0x80 ) {
 699                                 // Allow unicode if a single high-bit character appears
 700                                 $r0 = sprintf( '\x%02x', $ord0 );
 701                                 $allowUnicode = true;
 702                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 703                                 $r0 = '\\' . $d0;
 704                         } else {
 705                                 $r0 = $d0;
 706                         }
 707                         // Do the output
 708                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 709                                 // Range
 710                                 if ( $ord2 > $ord0 ) {
 711                                         // Empty range
 712                                 } elseif ( $ord0 >= 0x80 ) {
 713                                         // Unicode range
 714                                         $allowUnicode = true;
 715                                         if ( $ord2 < 0x80 ) {
 716                                                 // Keep the non-unicode section of the range
 717                                                 $out .= "$r2-\\x7F";
 718                                         }
 719                                 } else {
 720                                         // Normal range
 721                                         $out .= "$r2-$r0";
 722                                 }
 723                                 // Reset state to the initial value
 724                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 725                         } elseif ( $ord2 < 0x80 ) {
 726                                 // ASCII character
 727                                 $out .= $r2;
 728                         }
 729                 }
 730                 if ( $ord1 < 0x80 ) {
 731                         $out .= $r1;
 732                 }
 733                 if ( $ord0 < 0x80 ) {
 734                         $out .= $r0;
 735                 }
 736                 if ( $allowUnicode ) {
 737                         $out .= '\u0080-\uFFFF';
 738                 }
 739                 return $out;
 740         }
 741
 742         /**
 743          * Make a prefixed DB key from a DB key and a namespace index
 744          *
 745          * @param int $ns Numerical representation of the namespace
 746          * @param string $title The DB key form the title
 747          * @param string $fragment The link fragment (after the "#")
 748          * @param string $interwiki The interwiki prefix
 749          * @param bool $canonicalNamespace If true, use the canonical name for
 750          *   $ns instead of the localized version.
 751          * @return string The prefixed form of the title
 752          */
 753         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 754                 $canonicalNamespace = false
 755         ) {
 756                 if ( $canonicalNamespace ) {
 757                         $namespace = MWNamespace::getCanonicalName( $ns );
 758                 } else {
 759                         $namespace = MediaWikiServices::getInstance()->getContentLanguage()->getNsText( $ns );
 760                 }
 761                 $name = $namespace == '' ? $title : "$namespace:$title";
 762                 if ( strval( $interwiki ) != '' ) {
 763                         $name = "$interwiki:$name";
 764                 }
 765                 if ( strval( $fragment ) != '' ) {
 766                         $name .= '#' . $fragment;
 767                 }
 768                 return $name;
 769         }
 770
 771         /**
 772          * Callback for usort() to do title sorts by (namespace, title)
 773          *
 774          * @param LinkTarget $a
 775          * @param LinkTarget $b
 776          *
 777          * @return int Result of string comparison, or namespace comparison
 778          */
 779         public static function compare( LinkTarget $a, LinkTarget $b ) {
 780                 return $a->getNamespace() <=> $b->getNamespace()
 781                         ?: strcmp( $a->getText(), $b->getText() );
 782         }
 783
 784         /**
 785          * Returns true if the title is valid, false if it is invalid.
 786          *
 787          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 788          * Invalid titles may get returned from makeTitle(), and it may be useful to
 789          * allow them to exist, e.g. in order to process log entries about pages in
 790          * namespaces that belong to extensions that are no longer installed.
 791          *
 792          * @note This method is relatively expensive. When constructing Title
 793          * objects that need to be valid, use an instantiator method that is guaranteed
 794          * to return valid titles, such as makeTitleSafe() or newFromText().
 795          *
 796          * @return bool
 797          */
 798         public function isValid() {
 799                 if ( !MWNamespace::exists( $this->mNamespace ) ) {
 800                         return false;
 801                 }
 802
 803                 try {
 804                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 805                         $parser->parseTitle( $this->mDbkeyform, $this->mNamespace );
 806                         return true;
 807                 } catch ( MalformedTitleException $ex ) {
 808                         return false;
 809                 }
 810         }
 811
 812         /**
 813          * Determine whether the object refers to a page within
 814          * this project (either this wiki or a wiki with a local
 815          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 816          *
 817          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 818          */
 819         public function isLocal() {
 820                 if ( $this->isExternal() ) {
 821                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 822                         if ( $iw ) {
 823                                 return $iw->isLocal();
 824                         }
 825                 }
 826                 return true;
 827         }
 828
 829         /**
 830          * Is this Title interwiki?
 831          *
 832          * @return bool
 833          */
 834         public function isExternal() {
 835                 return $this->mInterwiki !== '';
 836         }
 837
 838         /**
 839          * Get the interwiki prefix
 840          *
 841          * Use Title::isExternal to check if a interwiki is set
 842          *
 843          * @return string Interwiki prefix
 844          */
 845         public function getInterwiki() {
 846                 return $this->mInterwiki;
 847         }
 848
 849         /**
 850          * Was this a local interwiki link?
 851          *
 852          * @return bool
 853          */
 854         public function wasLocalInterwiki() {
 855                 return $this->mLocalInterwiki;
 856         }
 857
 858         /**
 859          * Determine whether the object refers to a page within
 860          * this project and is transcludable.
 861          *
 862          * @return bool True if this is transcludable
 863          */
 864         public function isTrans() {
 865                 if ( !$this->isExternal() ) {
 866                         return false;
 867                 }
 868
 869                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 870         }
 871
 872         /**
 873          * Returns the DB name of the distant wiki which owns the object.
 874          *
 875          * @return string|false The DB name
 876          */
 877         public function getTransWikiID() {
 878                 if ( !$this->isExternal() ) {
 879                         return false;
 880                 }
 881
 882                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 883         }
 884
 885         /**
 886          * Get a TitleValue object representing this Title.
 887          *
 888          * @note Not all valid Titles have a corresponding valid TitleValue
 889          * (e.g. TitleValues cannot represent page-local links that have a
 890          * fragment but no title text).
 891          *
 892          * @return TitleValue|null
 893          */
 894         public function getTitleValue() {
 895                 if ( $this->mTitleValue === null ) {
 896                         try {
 897                                 $this->mTitleValue = new TitleValue(
 898                                         $this->mNamespace,
 899                                         $this->mDbkeyform,
 900                                         $this->mFragment,
 901                                         $this->mInterwiki
 902                                 );
 903                         } catch ( InvalidArgumentException $ex ) {
 904                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 905                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 906                         }
 907                 }
 908
 909                 return $this->mTitleValue;
 910         }
 911
 912         /**
 913          * Get the text form (spaces not underscores) of the main part
 914          *
 915          * @return string Main part of the title
 916          */
 917         public function getText() {
 918                 return $this->mTextform;
 919         }
 920
 921         /**
 922          * Get the URL-encoded form of the main part
 923          *
 924          * @return string Main part of the title, URL-encoded
 925          */
 926         public function getPartialURL() {
 927                 return $this->mUrlform;
 928         }
 929
 930         /**
 931          * Get the main part with underscores
 932          *
 933          * @return string Main part of the title, with underscores
 934          */
 935         public function getDBkey() {
 936                 return $this->mDbkeyform;
 937         }
 938
 939         /**
 940          * Get the DB key with the initial letter case as specified by the user
 941          * @deprecated since 1.33; please use Title::getDBKey() instead
 942          *
 943          * @return string DB key
 944          */
 945         function getUserCaseDBKey() {
 946                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 947                         return $this->mUserCaseDBKey;
 948                 } else {
 949                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 950                         return $this->mDbkeyform;
 951                 }
 952         }
 953
 954         /**
 955          * Get the namespace index, i.e. one of the NS_xxxx constants.
 956          *
 957          * @return int Namespace index
 958          */
 959         public function getNamespace() {
 960                 return $this->mNamespace;
 961         }
 962
 963         /**
 964          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 965          *
 966          * @todo Deprecate this in favor of SlotRecord::getModel()
 967          *
 968          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 969          * @return string Content model id
 970          */
 971         public function getContentModel( $flags = 0 ) {
 972                 if ( !$this->mForcedContentModel
 973                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 974                         && $this->getArticleID( $flags )
 975                 ) {
 976                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 977                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 978                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 979                 }
 980
 981                 if ( !$this->mContentModel ) {
 982                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 983                 }
 984
 985                 return $this->mContentModel;
 986         }
 987
 988         /**
 989          * Convenience method for checking a title's content model name
 990          *
 991          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 992          * @return bool True if $this->getContentModel() == $id
 993          */
 994         public function hasContentModel( $id ) {
 995                 return $this->getContentModel() == $id;
 996         }
 997
 998         /**
 999          * Set a proposed content model for the page for permissions
1000          * checking. This does not actually change the content model
1001          * of a title!
1002          *
1003          * Additionally, you should make sure you've checked
1004          * ContentHandler::canBeUsedOn() first.
1005          *
1006          * @since 1.28
1007          * @param string $model CONTENT_MODEL_XXX constant
1008          */
1009         public function setContentModel( $model ) {
1010                 $this->mContentModel = $model;
1011                 $this->mForcedContentModel = true;
1012         }
1013
1014         /**
1015          * Get the namespace text
1016          *
1017          * @return string|false Namespace text
1018          */
1019         public function getNsText() {
1020                 if ( $this->isExternal() ) {
1021                         // This probably shouldn't even happen, except for interwiki transclusion.
1022                         // If possible, use the canonical name for the foreign namespace.
1023                         $nsText = MWNamespace::getCanonicalName( $this->mNamespace );
1024                         if ( $nsText !== false ) {
1025                                 return $nsText;
1026                         }
1027                 }
1028
1029                 try {
1030                         $formatter = self::getTitleFormatter();
1031                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1032                 } catch ( InvalidArgumentException $ex ) {
1033                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1034                         return false;
1035                 }
1036         }
1037
1038         /**
1039          * Get the namespace text of the subject (rather than talk) page
1040          *
1041          * @return string Namespace text
1042          */
1043         public function getSubjectNsText() {
1044                 return MediaWikiServices::getInstance()->getContentLanguage()->
1045                         getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1046         }
1047
1048         /**
1049          * Get the namespace text of the talk page
1050          *
1051          * @return string Namespace text
1052          */
1053         public function getTalkNsText() {
1054                 return MediaWikiServices::getInstance()->getContentLanguage()->
1055                         getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1056         }
1057
1058         /**
1059          * Can this title have a corresponding talk page?
1060          *
1061          * @see MWNamespace::hasTalkNamespace
1062          * @since 1.30
1063          *
1064          * @return bool True if this title either is a talk page or can have a talk page associated.
1065          */
1066         public function canHaveTalkPage() {
1067                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1068         }
1069
1070         /**
1071          * Is this in a namespace that allows actual pages?
1072          *
1073          * @return bool
1074          */
1075         public function canExist() {
1076                 return $this->mNamespace >= NS_MAIN;
1077         }
1078
1079         /**
1080          * Can this title be added to a user's watchlist?
1081          *
1082          * @return bool
1083          */
1084         public function isWatchable() {
1085                 return !$this->isExternal() && MWNamespace::isWatchable( $this->mNamespace );
1086         }
1087
1088         /**
1089          * Returns true if this is a special page.
1090          *
1091          * @return bool
1092          */
1093         public function isSpecialPage() {
1094                 return $this->mNamespace == NS_SPECIAL;
1095         }
1096
1097         /**
1098          * Returns true if this title resolves to the named special page
1099          *
1100          * @param string $name The special page name
1101          * @return bool
1102          */
1103         public function isSpecial( $name ) {
1104                 if ( $this->isSpecialPage() ) {
1105                         list( $thisName, /* $subpage */ ) =
1106                                 MediaWikiServices::getInstance()->getSpecialPageFactory()->
1107                                         resolveAlias( $this->mDbkeyform );
1108                         if ( $name == $thisName ) {
1109                                 return true;
1110                         }
1111                 }
1112                 return false;
1113         }
1114
1115         /**
1116          * If the Title refers to a special page alias which is not the local default, resolve
1117          * the alias, and localise the name as necessary.  Otherwise, return $this
1118          *
1119          * @return Title
1120          */
1121         public function fixSpecialName() {
1122                 if ( $this->isSpecialPage() ) {
1123                         $spFactory = MediaWikiServices::getInstance()->getSpecialPageFactory();
1124                         list( $canonicalName, $par ) = $spFactory->resolveAlias( $this->mDbkeyform );
1125                         if ( $canonicalName ) {
1126                                 $localName = $spFactory->getLocalNameFor( $canonicalName, $par );
1127                                 if ( $localName != $this->mDbkeyform ) {
1128                                         return self::makeTitle( NS_SPECIAL, $localName );
1129                                 }
1130                         }
1131                 }
1132                 return $this;
1133         }
1134
1135         /**
1136          * Returns true if the title is inside the specified namespace.
1137          *
1138          * Please make use of this instead of comparing to getNamespace()
1139          * This function is much more resistant to changes we may make
1140          * to namespaces than code that makes direct comparisons.
1141          * @param int $ns The namespace
1142          * @return bool
1143          * @since 1.19
1144          */
1145         public function inNamespace( $ns ) {
1146                 return MWNamespace::equals( $this->mNamespace, $ns );
1147         }
1148
1149         /**
1150          * Returns true if the title is inside one of the specified namespaces.
1151          *
1152          * @param int|int[] $namespaces,... The namespaces to check for
1153          * @return bool
1154          * @since 1.19
1155          */
1156         public function inNamespaces( /* ... */ ) {
1157                 $namespaces = func_get_args();
1158                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1159                         $namespaces = $namespaces[0];
1160                 }
1161
1162                 foreach ( $namespaces as $ns ) {
1163                         if ( $this->inNamespace( $ns ) ) {
1164                                 return true;
1165                         }
1166                 }
1167
1168                 return false;
1169         }
1170
1171         /**
1172          * Returns true if the title has the same subject namespace as the
1173          * namespace specified.
1174          * For example this method will take NS_USER and return true if namespace
1175          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1176          * as their subject namespace.
1177          *
1178          * This is MUCH simpler than individually testing for equivalence
1179          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1180          * @since 1.19
1181          * @param int $ns
1182          * @return bool
1183          */
1184         public function hasSubjectNamespace( $ns ) {
1185                 return MWNamespace::subjectEquals( $this->mNamespace, $ns );
1186         }
1187
1188         /**
1189          * Is this Title in a namespace which contains content?
1190          * In other words, is this a content page, for the purposes of calculating
1191          * statistics, etc?
1192          *
1193          * @return bool
1194          */
1195         public function isContentPage() {
1196                 return MWNamespace::isContent( $this->mNamespace );
1197         }
1198
1199         /**
1200          * Would anybody with sufficient privileges be able to move this page?
1201          * Some pages just aren't movable.
1202          *
1203          * @return bool
1204          */
1205         public function isMovable() {
1206                 if ( !MWNamespace::isMovable( $this->mNamespace ) || $this->isExternal() ) {
1207                         // Interwiki title or immovable namespace. Hooks don't get to override here
1208                         return false;
1209                 }
1210
1211                 $result = true;
1212                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1213                 return $result;
1214         }
1215
1216         /**
1217          * Is this the mainpage?
1218          * @note Title::newFromText seems to be sufficiently optimized by the title
1219          * cache that we don't need to over-optimize by doing direct comparisons and
1220          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1221          * ends up reporting something differently than $title->isMainPage();
1222          *
1223          * @since 1.18
1224          * @return bool
1225          */
1226         public function isMainPage() {
1227                 return $this->equals( self::newMainPage() );
1228         }
1229
1230         /**
1231          * Is this a subpage?
1232          *
1233          * @return bool
1234          */
1235         public function isSubpage() {
1236                 return MWNamespace::hasSubpages( $this->mNamespace )
1237                         ? strpos( $this->getText(), '/' ) !== false
1238                         : false;
1239         }
1240
1241         /**
1242          * Is this a conversion table for the LanguageConverter?
1243          *
1244          * @return bool
1245          */
1246         public function isConversionTable() {
1247                 // @todo ConversionTable should become a separate content model.
1248
1249                 return $this->mNamespace == NS_MEDIAWIKI &&
1250                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1251         }
1252
1253         /**
1254          * Does that page contain wikitext, or it is JS, CSS or whatever?
1255          *
1256          * @return bool
1257          */
1258         public function isWikitextPage() {
1259                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1260         }
1261
1262         /**
1263          * Could this MediaWiki namespace page contain custom CSS, JSON, or JavaScript for the
1264          * global UI. This is generally true for pages in the MediaWiki namespace having
1265          * CONTENT_MODEL_CSS, CONTENT_MODEL_JSON, or CONTENT_MODEL_JAVASCRIPT.
1266          *
1267          * This method does *not* return true for per-user JS/JSON/CSS. Use isUserConfigPage()
1268          * for that!
1269          *
1270          * Note that this method should not return true for pages that contain and show
1271          * "inactive" CSS, JSON, or JS.
1272          *
1273          * @return bool
1274          * @since 1.31
1275          */
1276         public function isSiteConfigPage() {
1277                 return (
1278                         $this->isSiteCssConfigPage()
1279                         || $this->isSiteJsonConfigPage()
1280                         || $this->isSiteJsConfigPage()
1281                 );
1282         }
1283
1284         /**
1285          * Is this a "config" (.css, .json, or .js) sub-page of a user page?
1286          *
1287          * @return bool
1288          * @since 1.31
1289          */
1290         public function isUserConfigPage() {
1291                 return (
1292                         $this->isUserCssConfigPage()
1293                         || $this->isUserJsonConfigPage()
1294                         || $this->isUserJsConfigPage()
1295                 );
1296         }
1297
1298         /**
1299          * Trim down a .css, .json, or .js subpage title to get the corresponding skin name
1300          *
1301          * @return string Containing skin name from .css, .json, or .js subpage title
1302          * @since 1.31
1303          */
1304         public function getSkinFromConfigSubpage() {
1305                 $subpage = explode( '/', $this->mTextform );
1306                 $subpage = $subpage[count( $subpage ) - 1];
1307                 $lastdot = strrpos( $subpage, '.' );
1308                 if ( $lastdot === false ) {
1309                         return $subpage; # Never happens: only called for names ending in '.css'/'.json'/'.js'
1310                 }
1311                 return substr( $subpage, 0, $lastdot );
1312         }
1313
1314         /**
1315          * Is this a CSS "config" sub-page of a user page?
1316          *
1317          * @return bool
1318          * @since 1.31
1319          */
1320         public function isUserCssConfigPage() {
1321                 return (
1322                         NS_USER == $this->mNamespace
1323                         && $this->isSubpage()
1324                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1325                 );
1326         }
1327
1328         /**
1329          * Is this a JSON "config" sub-page of a user page?
1330          *
1331          * @return bool
1332          * @since 1.31
1333          */
1334         public function isUserJsonConfigPage() {
1335                 return (
1336                         NS_USER == $this->mNamespace
1337                         && $this->isSubpage()
1338                         && $this->hasContentModel( CONTENT_MODEL_JSON )
1339                 );
1340         }
1341
1342         /**
1343          * Is this a JS "config" sub-page of a user page?
1344          *
1345          * @return bool
1346          * @since 1.31
1347          */
1348         public function isUserJsConfigPage() {
1349                 return (
1350                         NS_USER == $this->mNamespace
1351                         && $this->isSubpage()
1352                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1353                 );
1354         }
1355
1356         /**
1357          * Is this a sitewide CSS "config" page?
1358          *
1359          * @return bool
1360          * @since 1.32
1361          */
1362         public function isSiteCssConfigPage() {
1363                 return (
1364                         NS_MEDIAWIKI == $this->mNamespace
1365                         && (
1366                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1367                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1368                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1369                                 || substr( $this->mDbkeyform, -4 ) === '.css'
1370                         )
1371                 );
1372         }
1373
1374         /**
1375          * Is this a sitewide JSON "config" page?
1376          *
1377          * @return bool
1378          * @since 1.32
1379          */
1380         public function isSiteJsonConfigPage() {
1381                 return (
1382                         NS_MEDIAWIKI == $this->mNamespace
1383                         && (
1384                                 $this->hasContentModel( CONTENT_MODEL_JSON )
1385                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1386                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1387                                 || substr( $this->mDbkeyform, -5 ) === '.json'
1388                         )
1389                 );
1390         }
1391
1392         /**
1393          * Is this a sitewide JS "config" page?
1394          *
1395          * @return bool
1396          * @since 1.31
1397          */
1398         public function isSiteJsConfigPage() {
1399                 return (
1400                         NS_MEDIAWIKI == $this->mNamespace
1401                         && (
1402                                 $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1403                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1404                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1405                                 || substr( $this->mDbkeyform, -3 ) === '.js'
1406                         )
1407                 );
1408         }
1409
1410         /**
1411          * Is this a message which can contain raw HTML?
1412          *
1413          * @return bool
1414          * @since 1.32
1415          */
1416         public function isRawHtmlMessage() {
1417                 global $wgRawHtmlMessages;
1418
1419                 if ( !$this->inNamespace( NS_MEDIAWIKI ) ) {
1420                         return false;
1421                 }
1422                 $message = lcfirst( $this->getRootTitle()->getDBkey() );
1423                 return in_array( $message, $wgRawHtmlMessages, true );
1424         }
1425
1426         /**
1427          * Is this a talk page of some sort?
1428          *
1429          * @return bool
1430          */
1431         public function isTalkPage() {
1432                 return MWNamespace::isTalk( $this->mNamespace );
1433         }
1434
1435         /**
1436          * Get a Title object associated with the talk page of this article
1437          *
1438          * @return Title The object for the talk page
1439          */
1440         public function getTalkPage() {
1441                 return self::makeTitle( MWNamespace::getTalk( $this->mNamespace ), $this->mDbkeyform );
1442         }
1443
1444         /**
1445          * Get a Title object associated with the talk page of this article,
1446          * if such a talk page can exist.
1447          *
1448          * @since 1.30
1449          *
1450          * @return Title|null The object for the talk page,
1451          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1452          */
1453         public function getTalkPageIfDefined() {
1454                 if ( !$this->canHaveTalkPage() ) {
1455                         return null;
1456                 }
1457
1458                 return $this->getTalkPage();
1459         }
1460
1461         /**
1462          * Get a title object associated with the subject page of this
1463          * talk page
1464          *
1465          * @return Title The object for the subject page
1466          */
1467         public function getSubjectPage() {
1468                 // Is this the same title?
1469                 $subjectNS = MWNamespace::getSubject( $this->mNamespace );
1470                 if ( $this->mNamespace == $subjectNS ) {
1471                         return $this;
1472                 }
1473                 return self::makeTitle( $subjectNS, $this->mDbkeyform );
1474         }
1475
1476         /**
1477          * Get the other title for this page, if this is a subject page
1478          * get the talk page, if it is a subject page get the talk page
1479          *
1480          * @since 1.25
1481          * @throws MWException If the page doesn't have an other page
1482          * @return Title
1483          */
1484         public function getOtherPage() {
1485                 if ( $this->isSpecialPage() ) {
1486                         throw new MWException( 'Special pages cannot have other pages' );
1487                 }
1488                 if ( $this->isTalkPage() ) {
1489                         return $this->getSubjectPage();
1490                 } else {
1491                         if ( !$this->canHaveTalkPage() ) {
1492                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1493                         }
1494                         return $this->getTalkPage();
1495                 }
1496         }
1497
1498         /**
1499          * Get the default namespace index, for when there is no namespace
1500          *
1501          * @return int Default namespace index
1502          */
1503         public function getDefaultNamespace() {
1504                 return $this->mDefaultNamespace;
1505         }
1506
1507         /**
1508          * Get the Title fragment (i.e.\ the bit after the #) in text form
1509          *
1510          * Use Title::hasFragment to check for a fragment
1511          *
1512          * @return string Title fragment
1513          */
1514         public function getFragment() {
1515                 return $this->mFragment;
1516         }
1517
1518         /**
1519          * Check if a Title fragment is set
1520          *
1521          * @return bool
1522          * @since 1.23
1523          */
1524         public function hasFragment() {
1525                 return $this->mFragment !== '';
1526         }
1527
1528         /**
1529          * Get the fragment in URL form, including the "#" character if there is one
1530          *
1531          * @return string Fragment in URL form
1532          */
1533         public function getFragmentForURL() {
1534                 if ( !$this->hasFragment() ) {
1535                         return '';
1536                 } elseif ( $this->isExternal() ) {
1537                         // Note: If the interwiki is unknown, it's treated as a namespace on the local wiki,
1538                         // so we treat it like a local interwiki.
1539                         $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1540                         if ( $interwiki && !$interwiki->isLocal() ) {
1541                                 return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->mFragment );
1542                         }
1543                 }
1544
1545                 return '#' . Sanitizer::escapeIdForLink( $this->mFragment );
1546         }
1547
1548         /**
1549          * Set the fragment for this title. Removes the first character from the
1550          * specified fragment before setting, so it assumes you're passing it with
1551          * an initial "#".
1552          *
1553          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1554          * or Title::createFragmentTarget().
1555          * Still in active use privately.
1556          *
1557          * @private
1558          * @param string $fragment Text
1559          */
1560         public function setFragment( $fragment ) {
1561                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1562         }
1563
1564         /**
1565          * Creates a new Title for a different fragment of the same page.
1566          *
1567          * @since 1.27
1568          * @param string $fragment
1569          * @return Title
1570          */
1571         public function createFragmentTarget( $fragment ) {
1572                 return self::makeTitle(
1573                         $this->mNamespace,
1574                         $this->getText(),
1575                         $fragment,
1576                         $this->mInterwiki
1577                 );
1578         }
1579
1580         /**
1581          * Prefix some arbitrary text with the namespace or interwiki prefix
1582          * of this object
1583          *
1584          * @param string $name The text
1585          * @return string The prefixed text
1586          */
1587         private function prefix( $name ) {
1588                 $p = '';
1589                 if ( $this->isExternal() ) {
1590                         $p = $this->mInterwiki . ':';
1591                 }
1592
1593                 if ( $this->mNamespace != 0 ) {
1594                         $nsText = $this->getNsText();
1595
1596                         if ( $nsText === false ) {
1597                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1598                                 $nsText = MediaWikiServices::getInstance()->getContentLanguage()->
1599                                         getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1600                         }
1601
1602                         $p .= $nsText . ':';
1603                 }
1604                 return $p . $name;
1605         }
1606
1607         /**
1608          * Get the prefixed database key form
1609          *
1610          * @return string The prefixed title, with underscores and
1611          *  any interwiki and namespace prefixes
1612          */
1613         public function getPrefixedDBkey() {
1614                 $s = $this->prefix( $this->mDbkeyform );
1615                 $s = strtr( $s, ' ', '_' );
1616                 return $s;
1617         }
1618
1619         /**
1620          * Get the prefixed title with spaces.
1621          * This is the form usually used for display
1622          *
1623          * @return string The prefixed title, with spaces
1624          */
1625         public function getPrefixedText() {
1626                 if ( $this->prefixedText === null ) {
1627                         $s = $this->prefix( $this->mTextform );
1628                         $s = strtr( $s, '_', ' ' );
1629                         $this->prefixedText = $s;
1630                 }
1631                 return $this->prefixedText;
1632         }
1633
1634         /**
1635          * Return a string representation of this title
1636          *
1637          * @return string Representation of this title
1638          */
1639         public function __toString() {
1640                 return $this->getPrefixedText();
1641         }
1642
1643         /**
1644          * Get the prefixed title with spaces, plus any fragment
1645          * (part beginning with '#')
1646          *
1647          * @return string The prefixed title, with spaces and the fragment, including '#'
1648          */
1649         public function getFullText() {
1650                 $text = $this->getPrefixedText();
1651                 if ( $this->hasFragment() ) {
1652                         $text .= '#' . $this->mFragment;
1653                 }
1654                 return $text;
1655         }
1656
1657         /**
1658          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1659          *
1660          * @par Example:
1661          * @code
1662          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1663          * # returns: 'Foo'
1664          * @endcode
1665          *
1666          * @return string Root name
1667          * @since 1.20
1668          */
1669         public function getRootText() {
1670                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1671                         return $this->getText();
1672                 }
1673
1674                 return strtok( $this->getText(), '/' );
1675         }
1676
1677         /**
1678          * Get the root page name title, i.e. the leftmost part before any slashes
1679          *
1680          * @par Example:
1681          * @code
1682          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1683          * # returns: Title{User:Foo}
1684          * @endcode
1685          *
1686          * @return Title Root title
1687          * @since 1.20
1688          */
1689         public function getRootTitle() {
1690                 return self::makeTitle( $this->mNamespace, $this->getRootText() );
1691         }
1692
1693         /**
1694          * Get the base page name without a namespace, i.e. the part before the subpage name
1695          *
1696          * @par Example:
1697          * @code
1698          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1699          * # returns: 'Foo/Bar'
1700          * @endcode
1701          *
1702          * @return string Base name
1703          */
1704         public function getBaseText() {
1705                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1706                         return $this->getText();
1707                 }
1708
1709                 $parts = explode( '/', $this->getText() );
1710                 # Don't discard the real title if there's no subpage involved
1711                 if ( count( $parts ) > 1 ) {
1712                         unset( $parts[count( $parts ) - 1] );
1713                 }
1714                 return implode( '/', $parts );
1715         }
1716
1717         /**
1718          * Get the base page name title, i.e. the part before the subpage name
1719          *
1720          * @par Example:
1721          * @code
1722          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1723          * # returns: Title{User:Foo/Bar}
1724          * @endcode
1725          *
1726          * @return Title Base title
1727          * @since 1.20
1728          */
1729         public function getBaseTitle() {
1730                 return self::makeTitle( $this->mNamespace, $this->getBaseText() );
1731         }
1732
1733         /**
1734          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1735          *
1736          * @par Example:
1737          * @code
1738          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1739          * # returns: "Baz"
1740          * @endcode
1741          *
1742          * @return string Subpage name
1743          */
1744         public function getSubpageText() {
1745                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1746                         return $this->mTextform;
1747                 }
1748                 $parts = explode( '/', $this->mTextform );
1749                 return $parts[count( $parts ) - 1];
1750         }
1751
1752         /**
1753          * Get the title for a subpage of the current page
1754          *
1755          * @par Example:
1756          * @code
1757          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1758          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1759          * @endcode
1760          *
1761          * @param string $text The subpage name to add to the title
1762          * @return Title|null Subpage title, or null on an error
1763          * @since 1.20
1764          */
1765         public function getSubpage( $text ) {
1766                 return self::makeTitleSafe( $this->mNamespace, $this->getText() . '/' . $text );
1767         }
1768
1769         /**
1770          * Get a URL-encoded form of the subpage text
1771          *
1772          * @return string URL-encoded subpage name
1773          */
1774         public function getSubpageUrlForm() {
1775                 $text = $this->getSubpageText();
1776                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1777                 return $text;
1778         }
1779
1780         /**
1781          * Get a URL-encoded title (not an actual URL) including interwiki
1782          *
1783          * @return string The URL-encoded form
1784          */
1785         public function getPrefixedURL() {
1786                 $s = $this->prefix( $this->mDbkeyform );
1787                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1788                 return $s;
1789         }
1790
1791         /**
1792          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1793          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1794          * second argument named variant. This was deprecated in favor
1795          * of passing an array of option with a "variant" key
1796          * Once $query2 is removed for good, this helper can be dropped
1797          * and the wfArrayToCgi moved to getLocalURL();
1798          *
1799          * @since 1.19 (r105919)
1800          * @param array|string $query
1801          * @param string|string[]|bool $query2
1802          * @return string
1803          */
1804         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1805                 if ( $query2 !== false ) {
1806                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1807                                 "method called with a second parameter is deprecated. Add your " .
1808                                 "parameter to an array passed as the first parameter.", "1.19" );
1809                 }
1810                 if ( is_array( $query ) ) {
1811                         $query = wfArrayToCgi( $query );
1812                 }
1813                 if ( $query2 ) {
1814                         if ( is_string( $query2 ) ) {
1815                                 // $query2 is a string, we will consider this to be
1816                                 // a deprecated $variant argument and add it to the query
1817                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1818                         } else {
1819                                 $query2 = wfArrayToCgi( $query2 );
1820                         }
1821                         // If we have $query content add a & to it first
1822                         if ( $query ) {
1823                                 $query .= '&';
1824                         }
1825                         // Now append the queries together
1826                         $query .= $query2;
1827                 }
1828                 return $query;
1829         }
1830
1831         /**
1832          * Get a real URL referring to this title, with interwiki link and
1833          * fragment
1834          *
1835          * @see self::getLocalURL for the arguments.
1836          * @see wfExpandUrl
1837          * @param string|string[] $query
1838          * @param string|string[]|bool $query2
1839          * @param string|int|null $proto Protocol type to use in URL
1840          * @return string The URL
1841          */
1842         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1843                 $query = self::fixUrlQueryArgs( $query, $query2 );
1844
1845                 # Hand off all the decisions on urls to getLocalURL
1846                 $url = $this->getLocalURL( $query );
1847
1848                 # Expand the url to make it a full url. Note that getLocalURL has the
1849                 # potential to output full urls for a variety of reasons, so we use
1850                 # wfExpandUrl instead of simply prepending $wgServer
1851                 $url = wfExpandUrl( $url, $proto );
1852
1853                 # Finally, add the fragment.
1854                 $url .= $this->getFragmentForURL();
1855                 // Avoid PHP 7.1 warning from passing $this by reference
1856                 $titleRef = $this;
1857                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1858                 return $url;
1859         }
1860
1861         /**
1862          * Get a url appropriate for making redirects based on an untrusted url arg
1863          *
1864          * This is basically the same as getFullUrl(), but in the case of external
1865          * interwikis, we send the user to a landing page, to prevent possible
1866          * phishing attacks and the like.
1867          *
1868          * @note Uses current protocol by default, since technically relative urls
1869          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1870          *   places where the url gets cached, as might pollute between
1871          *   https and non-https users.
1872          * @see self::getLocalURL for the arguments.
1873          * @param array|string $query
1874          * @param string $proto Protocol type to use in URL
1875          * @return string A url suitable to use in an HTTP location header.
1876          */
1877         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1878                 $target = $this;
1879                 if ( $this->isExternal() ) {
1880                         $target = SpecialPage::getTitleFor(
1881                                 'GoToInterwiki',
1882                                 $this->getPrefixedDBkey()
1883                         );
1884                 }
1885                 return $target->getFullURL( $query, false, $proto );
1886         }
1887
1888         /**
1889          * Get a URL with no fragment or server name (relative URL) from a Title object.
1890          * If this page is generated with action=render, however,
1891          * $wgServer is prepended to make an absolute URL.
1892          *
1893          * @see self::getFullURL to always get an absolute URL.
1894          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1895          *  valid to link, locally, to the current Title.
1896          * @see self::newFromText to produce a Title object.
1897          *
1898          * @param string|string[] $query An optional query string,
1899          *   not used for interwiki links. Can be specified as an associative array as well,
1900          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1901          *   Some query patterns will trigger various shorturl path replacements.
1902          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1903          *   be an array. If a string is passed it will be interpreted as a deprecated
1904          *   variant argument and urlencoded into a variant= argument.
1905          *   This second query argument will be added to the $query
1906          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1907          *   pair in the first parameter array instead.
1908          *
1909          * @return string String of the URL.
1910          */
1911         public function getLocalURL( $query = '', $query2 = false ) {
1912                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1913
1914                 $query = self::fixUrlQueryArgs( $query, $query2 );
1915
1916                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1917                 if ( $interwiki ) {
1918                         $namespace = $this->getNsText();
1919                         if ( $namespace != '' ) {
1920                                 # Can this actually happen? Interwikis shouldn't be parsed.
1921                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1922                                 $namespace .= ':';
1923                         }
1924                         $url = $interwiki->getURL( $namespace . $this->mDbkeyform );
1925                         $url = wfAppendQuery( $url, $query );
1926                 } else {
1927                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1928                         if ( $query == '' ) {
1929                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1930                                 // Avoid PHP 7.1 warning from passing $this by reference
1931                                 $titleRef = $this;
1932                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1933                         } else {
1934                                 global $wgVariantArticlePath, $wgActionPaths;
1935                                 $url = false;
1936                                 $matches = [];
1937
1938                                 if ( !empty( $wgActionPaths )
1939                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1940                                 ) {
1941                                         $action = urldecode( $matches[2] );
1942                                         if ( isset( $wgActionPaths[$action] ) ) {
1943                                                 $query = $matches[1];
1944                                                 if ( isset( $matches[4] ) ) {
1945                                                         $query .= $matches[4];
1946                                                 }
1947                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1948                                                 if ( $query != '' ) {
1949                                                         $url = wfAppendQuery( $url, $query );
1950                                                 }
1951                                         }
1952                                 }
1953
1954                                 if ( $url === false
1955                                         && $wgVariantArticlePath
1956                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1957                                         && $this->getPageLanguage()->equals(
1958                                                 MediaWikiServices::getInstance()->getContentLanguage() )
1959                                         && $this->getPageLanguage()->hasVariants()
1960                                 ) {
1961                                         $variant = urldecode( $matches[1] );
1962                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1963                                                 // Only do the variant replacement if the given variant is a valid
1964                                                 // variant for the page's language.
1965                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1966                                                 $url = str_replace( '$1', $dbkey, $url );
1967                                         }
1968                                 }
1969
1970                                 if ( $url === false ) {
1971                                         if ( $query == '-' ) {
1972                                                 $query = '';
1973                                         }
1974                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1975                                 }
1976                         }
1977                         // Avoid PHP 7.1 warning from passing $this by reference
1978                         $titleRef = $this;
1979                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1980
1981                         // @todo FIXME: This causes breakage in various places when we
1982                         // actually expected a local URL and end up with dupe prefixes.
1983                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1984                                 $url = $wgServer . $url;
1985                         }
1986                 }
1987                 // Avoid PHP 7.1 warning from passing $this by reference
1988                 $titleRef = $this;
1989                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1990                 return $url;
1991         }
1992
1993         /**
1994          * Get a URL that's the simplest URL that will be valid to link, locally,
1995          * to the current Title.  It includes the fragment, but does not include
1996          * the server unless action=render is used (or the link is external).  If
1997          * there's a fragment but the prefixed text is empty, we just return a link
1998          * to the fragment.
1999          *
2000          * The result obviously should not be URL-escaped, but does need to be
2001          * HTML-escaped if it's being output in HTML.
2002          *
2003          * @param string|string[] $query
2004          * @param bool $query2
2005          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2006          *                               or false (default) for no expansion
2007          * @see self::getLocalURL for the arguments.
2008          * @return string The URL
2009          */
2010         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2011                 if ( $this->isExternal() || $proto !== false ) {
2012                         $ret = $this->getFullURL( $query, $query2, $proto );
2013                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2014                         $ret = $this->getFragmentForURL();
2015                 } else {
2016                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2017                 }
2018                 return $ret;
2019         }
2020
2021         /**
2022          * Get the URL form for an internal link.
2023          * - Used in various CDN-related code, in case we have a different
2024          * internal hostname for the server from the exposed one.
2025          *
2026          * This uses $wgInternalServer to qualify the path, or $wgServer
2027          * if $wgInternalServer is not set. If the server variable used is
2028          * protocol-relative, the URL will be expanded to http://
2029          *
2030          * @see self::getLocalURL for the arguments.
2031          * @param string $query
2032          * @param string|bool $query2
2033          * @return string The URL
2034          */
2035         public function getInternalURL( $query = '', $query2 = false ) {
2036                 global $wgInternalServer, $wgServer;
2037                 $query = self::fixUrlQueryArgs( $query, $query2 );
2038                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2039                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2040                 // Avoid PHP 7.1 warning from passing $this by reference
2041                 $titleRef = $this;
2042                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2043                 return $url;
2044         }
2045
2046         /**
2047          * Get the URL for a canonical link, for use in things like IRC and
2048          * e-mail notifications. Uses $wgCanonicalServer and the
2049          * GetCanonicalURL hook.
2050          *
2051          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2052          *
2053          * @see self::getLocalURL for the arguments.
2054          * @param string $query
2055          * @param string|bool $query2
2056          * @return string The URL
2057          * @since 1.18
2058          */
2059         public function getCanonicalURL( $query = '', $query2 = false ) {
2060                 $query = self::fixUrlQueryArgs( $query, $query2 );
2061                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2062                 // Avoid PHP 7.1 warning from passing $this by reference
2063                 $titleRef = $this;
2064                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2065                 return $url;
2066         }
2067
2068         /**
2069          * Get the edit URL for this Title
2070          *
2071          * @return string The URL, or a null string if this is an interwiki link
2072          */
2073         public function getEditURL() {
2074                 if ( $this->isExternal() ) {
2075                         return '';
2076                 }
2077                 $s = $this->getLocalURL( 'action=edit' );
2078
2079                 return $s;
2080         }
2081
2082         /**
2083          * Can $user perform $action on this page?
2084          * This skips potentially expensive cascading permission checks
2085          * as well as avoids expensive error formatting
2086          *
2087          * Suitable for use for nonessential UI controls in common cases, but
2088          * _not_ for functional access control.
2089          *
2090          * May provide false positives, but should never provide a false negative.
2091          *
2092          * @param string $action Action that permission needs to be checked for
2093          * @param User|null $user User to check (since 1.19); $wgUser will be used if not provided.
2094          * @return bool
2095          */
2096         public function quickUserCan( $action, $user = null ) {
2097                 return $this->userCan( $action, $user, false );
2098         }
2099
2100         /**
2101          * Can $user perform $action on this page?
2102          *
2103          * @param string $action Action that permission needs to be checked for
2104          * @param User|null $user User to check (since 1.19); $wgUser will be used if not
2105          *   provided.
2106          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2107          * @return bool
2108          */
2109         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2110                 if ( !$user instanceof User ) {
2111                         global $wgUser;
2112                         $user = $wgUser;
2113                 }
2114
2115                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2116         }
2117
2118         /**
2119          * Can $user perform $action on this page?
2120          *
2121          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2122          *
2123          * @param string $action Action that permission needs to be checked for
2124          * @param User $user User to check
2125          * @param string $rigor One of (quick,full,secure)
2126          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2127          *   - full   : does cheap and expensive checks possibly from a replica DB
2128          *   - secure : does cheap and expensive checks, using the master as needed
2129          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2130          *   whose corresponding errors may be ignored.
2131          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2132          */
2133         public function getUserPermissionsErrors(
2134                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2135         ) {
2136                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2137
2138                 // Remove the errors being ignored.
2139                 foreach ( $errors as $index => $error ) {
2140                         $errKey = is_array( $error ) ? $error[0] : $error;
2141
2142                         if ( in_array( $errKey, $ignoreErrors ) ) {
2143                                 unset( $errors[$index] );
2144                         }
2145                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2146                                 unset( $errors[$index] );
2147                         }
2148                 }
2149
2150                 return $errors;
2151         }
2152
2153         /**
2154          * Permissions checks that fail most often, and which are easiest to test.
2155          *
2156          * @param string $action The action to check
2157          * @param User $user User to check
2158          * @param array $errors List of current errors
2159          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2160          * @param bool $short Short circuit on first error
2161          *
2162          * @return array List of errors
2163          */
2164         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2165                 if ( !Hooks::run( 'TitleQuickPermissions',
2166                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2167                 ) {
2168                         return $errors;
2169                 }
2170
2171                 if ( $action == 'create' ) {
2172                         if (
2173                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2174                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2175                         ) {
2176                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2177                         }
2178                 } elseif ( $action == 'move' ) {
2179                         if ( !$user->isAllowed( 'move-rootuserpages' )
2180                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2181                                 // Show user page-specific message only if the user can move other pages
2182                                 $errors[] = [ 'cant-move-user-page' ];
2183                         }
2184
2185                         // Check if user is allowed to move files if it's a file
2186                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2187                                 $errors[] = [ 'movenotallowedfile' ];
2188                         }
2189
2190                         // Check if user is allowed to move category pages if it's a category page
2191                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2192                                 $errors[] = [ 'cant-move-category-page' ];
2193                         }
2194
2195                         if ( !$user->isAllowed( 'move' ) ) {
2196                                 // User can't move anything
2197                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2198                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2199                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2200                                         // custom message if logged-in users without any special rights can move
2201                                         $errors[] = [ 'movenologintext' ];
2202                                 } else {
2203                                         $errors[] = [ 'movenotallowed' ];
2204                                 }
2205                         }
2206                 } elseif ( $action == 'move-target' ) {
2207                         if ( !$user->isAllowed( 'move' ) ) {
2208                                 // User can't move anything
2209                                 $errors[] = [ 'movenotallowed' ];
2210                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2211                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2212                                 // Show user page-specific message only if the user can move other pages
2213                                 $errors[] = [ 'cant-move-to-user-page' ];
2214                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2215                                         && $this->mNamespace == NS_CATEGORY ) {
2216                                 // Show category page-specific message only if the user can move other pages
2217                                 $errors[] = [ 'cant-move-to-category-page' ];
2218                         }
2219                 } elseif ( !$user->isAllowed( $action ) ) {
2220                         $errors[] = $this->missingPermissionError( $action, $short );
2221                 }
2222
2223                 return $errors;
2224         }
2225
2226         /**
2227          * Add the resulting error code to the errors array
2228          *
2229          * @param array $errors List of current errors
2230          * @param array $result Result of errors
2231          *
2232          * @return array List of errors
2233          */
2234         private function resultToError( $errors, $result ) {
2235                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2236                         // A single array representing an error
2237                         $errors[] = $result;
2238                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2239                         // A nested array representing multiple errors
2240                         $errors = array_merge( $errors, $result );
2241                 } elseif ( $result !== '' && is_string( $result ) ) {
2242                         // A string representing a message-id
2243                         $errors[] = [ $result ];
2244                 } elseif ( $result instanceof MessageSpecifier ) {
2245                         // A message specifier representing an error
2246                         $errors[] = [ $result ];
2247                 } elseif ( $result === false ) {
2248                         // a generic "We don't want them to do that"
2249                         $errors[] = [ 'badaccess-group0' ];
2250                 }
2251                 return $errors;
2252         }
2253
2254         /**
2255          * Check various permission hooks
2256          *
2257          * @param string $action The action to check
2258          * @param User $user User to check
2259          * @param array $errors List of current errors
2260          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2261          * @param bool $short Short circuit on first error
2262          *
2263          * @return array List of errors
2264          */
2265         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2266                 // Use getUserPermissionsErrors instead
2267                 $result = '';
2268                 // Avoid PHP 7.1 warning from passing $this by reference
2269                 $titleRef = $this;
2270                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2271                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2272                 }
2273                 // Check getUserPermissionsErrors hook
2274                 // Avoid PHP 7.1 warning from passing $this by reference
2275                 $titleRef = $this;
2276                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2277                         $errors = $this->resultToError( $errors, $result );
2278                 }
2279                 // Check getUserPermissionsErrorsExpensive hook
2280                 if (
2281                         $rigor !== 'quick'
2282                         && !( $short && count( $errors ) > 0 )
2283                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2284                 ) {
2285                         $errors = $this->resultToError( $errors, $result );
2286                 }
2287
2288                 return $errors;
2289         }
2290
2291         /**
2292          * Check permissions on special pages & namespaces
2293          *
2294          * @param string $action The action to check
2295          * @param User $user User to check
2296          * @param array $errors List of current errors
2297          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2298          * @param bool $short Short circuit on first error
2299          *
2300          * @return array List of errors
2301          */
2302         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2303                 # Only 'createaccount' can be performed on special pages,
2304                 # which don't actually exist in the DB.
2305                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2306                         $errors[] = [ 'ns-specialprotected' ];
2307                 }
2308
2309                 # Check $wgNamespaceProtection for restricted namespaces
2310                 if ( $this->isNamespaceProtected( $user ) ) {
2311                         $ns = $this->mNamespace == NS_MAIN ?
2312                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2313                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2314                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2315                 }
2316
2317                 return $errors;
2318         }
2319
2320         /**
2321          * Check sitewide CSS/JSON/JS permissions
2322          *
2323          * @param string $action The action to check
2324          * @param User $user User to check
2325          * @param array $errors List of current errors
2326          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2327          * @param bool $short Short circuit on first error
2328          *
2329          * @return array List of errors
2330          */
2331         private function checkSiteConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2332                 if ( $action != 'patrol' ) {
2333                         $error = null;
2334                         // Sitewide CSS/JSON/JS changes, like all NS_MEDIAWIKI changes, also require the
2335                         // editinterface right. That's implemented as a restriction so no check needed here.
2336                         if ( $this->isSiteCssConfigPage() && !$user->isAllowed( 'editsitecss' ) ) {
2337                                 $error = [ 'sitecssprotected', $action ];
2338                         } elseif ( $this->isSiteJsonConfigPage() && !$user->isAllowed( 'editsitejson' ) ) {
2339                                 $error = [ 'sitejsonprotected', $action ];
2340                         } elseif ( $this->isSiteJsConfigPage() && !$user->isAllowed( 'editsitejs' ) ) {
2341                                 $error = [ 'sitejsprotected', $action ];
2342                         } elseif ( $this->isRawHtmlMessage() ) {
2343                                 // Raw HTML can be used to deploy CSS or JS so require rights for both.
2344                                 if ( !$user->isAllowed( 'editsitejs' ) ) {
2345                                         $error = [ 'sitejsprotected', $action ];
2346                                 } elseif ( !$user->isAllowed( 'editsitecss' ) ) {
2347                                         $error = [ 'sitecssprotected', $action ];
2348                                 }
2349                         }
2350
2351                         if ( $error ) {
2352                                 if ( $user->isAllowed( 'editinterface' ) ) {
2353                                         // Most users / site admins will probably find out about the new, more restrictive
2354                                         // permissions by failing to edit something. Give them more info.
2355                                         // TODO remove this a few release cycles after 1.32
2356                                         $error = [ 'interfaceadmin-info', wfMessage( $error[0], $error[1] ) ];
2357                                 }
2358                                 $errors[] = $error;
2359                         }
2360                 }
2361
2362                 return $errors;
2363         }
2364
2365         /**
2366          * Check CSS/JSON/JS sub-page permissions
2367          *
2368          * @param string $action The action to check
2369          * @param User $user User to check
2370          * @param array $errors List of current errors
2371          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2372          * @param bool $short Short circuit on first error
2373          *
2374          * @return array List of errors
2375          */
2376         private function checkUserConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2377                 # Protect css/json/js subpages of user pages
2378                 # XXX: this might be better using restrictions
2379
2380                 if ( $action === 'patrol' ) {
2381                         return $errors;
2382                 }
2383
2384                 if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2385                         // Users need editmyuser* to edit their own CSS/JSON/JS subpages.
2386                         if (
2387                                 $this->isUserCssConfigPage()
2388                                 && !$user->isAllowedAny( 'editmyusercss', 'editusercss' )
2389                         ) {
2390                                 $errors[] = [ 'mycustomcssprotected', $action ];
2391                         } elseif (
2392                                 $this->isUserJsonConfigPage()
2393                                 && !$user->isAllowedAny( 'editmyuserjson', 'edituserjson' )
2394                         ) {
2395                                 $errors[] = [ 'mycustomjsonprotected', $action ];
2396                         } elseif (
2397                                 $this->isUserJsConfigPage()
2398                                 && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' )
2399                         ) {
2400                                 $errors[] = [ 'mycustomjsprotected', $action ];
2401                         }
2402                 } else {
2403                         // Users need editmyuser* to edit their own CSS/JSON/JS subpages, except for
2404                         // deletion/suppression which cannot be used for attacks and we want to avoid the
2405                         // situation where an unprivileged user can post abusive content on their subpages
2406                         // and only very highly privileged users could remove it.
2407                         if ( !in_array( $action, [ 'delete', 'deleterevision', 'suppressrevision' ], true ) ) {
2408                                 if (
2409                                         $this->isUserCssConfigPage()
2410                                         && !$user->isAllowed( 'editusercss' )
2411                                 ) {
2412                                         $errors[] = [ 'customcssprotected', $action ];
2413                                 } elseif (
2414                                         $this->isUserJsonConfigPage()
2415                                         && !$user->isAllowed( 'edituserjson' )
2416                                 ) {
2417                                         $errors[] = [ 'customjsonprotected', $action ];
2418                                 } elseif (
2419                                         $this->isUserJsConfigPage()
2420                                         && !$user->isAllowed( 'edituserjs' )
2421                                 ) {
2422                                         $errors[] = [ 'customjsprotected', $action ];
2423                                 }
2424                         }
2425                 }
2426
2427                 return $errors;
2428         }
2429
2430         /**
2431          * Check against page_restrictions table requirements on this
2432          * page. The user must possess all required rights for this
2433          * action.
2434          *
2435          * @param string $action The action to check
2436          * @param User $user User to check
2437          * @param array $errors List of current errors
2438          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2439          * @param bool $short Short circuit on first error
2440          *
2441          * @return array List of errors
2442          */
2443         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2444                 foreach ( $this->getRestrictions( $action ) as $right ) {
2445                         // Backwards compatibility, rewrite sysop -> editprotected
2446                         if ( $right == 'sysop' ) {
2447                                 $right = 'editprotected';
2448                         }
2449                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2450                         if ( $right == 'autoconfirmed' ) {
2451                                 $right = 'editsemiprotected';
2452                         }
2453                         if ( $right == '' ) {
2454                                 continue;
2455                         }
2456                         if ( !$user->isAllowed( $right ) ) {
2457                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2458                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2459                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2460                         }
2461                 }
2462
2463                 return $errors;
2464         }
2465
2466         /**
2467          * Check restrictions on cascading pages.
2468          *
2469          * @param string $action The action to check
2470          * @param User $user User to check
2471          * @param array $errors List of current errors
2472          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2473          * @param bool $short Short circuit on first error
2474          *
2475          * @return array List of errors
2476          */
2477         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2478                 if ( $rigor !== 'quick' && !$this->isUserConfigPage() ) {
2479                         # We /could/ use the protection level on the source page, but it's
2480                         # fairly ugly as we have to establish a precedence hierarchy for pages
2481                         # included by multiple cascade-protected pages. So just restrict
2482                         # it to people with 'protect' permission, as they could remove the
2483                         # protection anyway.
2484                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2485                         # Cascading protection depends on more than this page...
2486                         # Several cascading protected pages may include this page...
2487                         # Check each cascading level
2488                         # This is only for protection restrictions, not for all actions
2489                         if ( isset( $restrictions[$action] ) ) {
2490                                 foreach ( $restrictions[$action] as $right ) {
2491                                         // Backwards compatibility, rewrite sysop -> editprotected
2492                                         if ( $right == 'sysop' ) {
2493                                                 $right = 'editprotected';
2494                                         }
2495                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2496                                         if ( $right == 'autoconfirmed' ) {
2497                                                 $right = 'editsemiprotected';
2498                                         }
2499                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2500                                                 $pages = '';
2501                                                 foreach ( $cascadingSources as $page ) {
2502                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2503                                                 }
2504                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2505                                         }
2506                                 }
2507                         }
2508                 }
2509
2510                 return $errors;
2511         }
2512
2513         /**
2514          * Check action permissions not already checked in checkQuickPermissions
2515          *
2516          * @param string $action The action to check
2517          * @param User $user User to check
2518          * @param array $errors List of current errors
2519          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2520          * @param bool $short Short circuit on first error
2521          *
2522          * @return array List of errors
2523          */
2524         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2525                 global $wgDeleteRevisionsLimit, $wgLang;
2526
2527                 if ( $action == 'protect' ) {
2528                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2529                                 // If they can't edit, they shouldn't protect.
2530                                 $errors[] = [ 'protect-cantedit' ];
2531                         }
2532                 } elseif ( $action == 'create' ) {
2533                         $title_protection = $this->getTitleProtection();
2534                         if ( $title_protection ) {
2535                                 if ( $title_protection['permission'] == ''
2536                                         || !$user->isAllowed( $title_protection['permission'] )
2537                                 ) {
2538                                         $errors[] = [
2539                                                 'titleprotected',
2540                                                 User::whoIs( $title_protection['user'] ),
2541                                                 $title_protection['reason']
2542                                         ];
2543                                 }
2544                         }
2545                 } elseif ( $action == 'move' ) {
2546                         // Check for immobile pages
2547                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2548                                 // Specific message for this case
2549                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2550                         } elseif ( !$this->isMovable() ) {
2551                                 // Less specific message for rarer cases
2552                                 $errors[] = [ 'immobile-source-page' ];
2553                         }
2554                 } elseif ( $action == 'move-target' ) {
2555                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2556                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2557                         } elseif ( !$this->isMovable() ) {
2558                                 $errors[] = [ 'immobile-target-page' ];
2559                         }
2560                 } elseif ( $action == 'delete' ) {
2561                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2562                         if ( !$tempErrors ) {
2563                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2564                                         $user, $tempErrors, $rigor, true );
2565                         }
2566                         if ( $tempErrors ) {
2567                                 // If protection keeps them from editing, they shouldn't be able to delete.
2568                                 $errors[] = [ 'deleteprotected' ];
2569                         }
2570                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2571                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2572                         ) {
2573                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2574                         }
2575                 } elseif ( $action === 'undelete' ) {
2576                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2577                                 // Undeleting implies editing
2578                                 $errors[] = [ 'undelete-cantedit' ];
2579                         }
2580                         if ( !$this->exists()
2581                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2582                         ) {
2583                                 // Undeleting where nothing currently exists implies creating
2584                                 $errors[] = [ 'undelete-cantcreate' ];
2585                         }
2586                 }
2587                 return $errors;
2588         }
2589
2590         /**
2591          * Check that the user isn't blocked from editing.
2592          *
2593          * @param string $action The action to check
2594          * @param User $user User to check
2595          * @param array $errors List of current errors
2596          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2597          * @param bool $short Short circuit on first error
2598          *
2599          * @return array List of errors
2600          */
2601         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2602                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2603                 // Account creation blocks handled at userlogin.
2604                 // Unblocking handled in SpecialUnblock
2605                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2606                         return $errors;
2607                 }
2608
2609                 // Optimize for a very common case
2610                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2611                         return $errors;
2612                 }
2613
2614                 if ( $wgEmailConfirmToEdit
2615                         && !$user->isEmailConfirmed()
2616                         && $action === 'edit'
2617                 ) {
2618                         $errors[] = [ 'confirmedittext' ];
2619                 }
2620
2621                 $useReplica = ( $rigor !== 'secure' );
2622                 $block = $user->getBlock( $useReplica );
2623
2624                 // If the user does not have a block, or the block they do have explicitly
2625                 // allows the action (like "read" or "upload").
2626                 if ( !$block || $block->appliesToRight( $action ) === false ) {
2627                         return $errors;
2628                 }
2629
2630                 // Determine if the user is blocked from this action on this page.
2631                 // What gets passed into this method is a user right, not an action name.
2632                 // There is no way to instantiate an action by restriction. However, this
2633                 // will get the action where the restriction is the same. This may result
2634                 // in actions being blocked that shouldn't be.
2635                 $actionObj = null;
2636                 if ( Action::exists( $action ) ) {
2637                         // Clone the title to prevent mutations to this object which is done
2638                         // by Title::loadFromRow() in WikiPage::loadFromRow().
2639                         $page = WikiPage::factory( clone $this );
2640                         // Creating an action will perform several database queries to ensure that
2641                         // the action has not been overridden by the content type.
2642                         // @todo FIXME: Pass the relevant context into this function.
2643                         $actionObj = Action::factory( $action, $page, RequestContext::getMain() );
2644                         // Ensure that the retrieved action matches the restriction.
2645                         if ( $actionObj && $actionObj->getRestriction() !== $action ) {
2646                                 $actionObj = null;
2647                         }
2648                 }
2649
2650                 // If no action object is returned, assume that the action requires unblock
2651                 // which is the default.
2652                 if ( !$actionObj || $actionObj->requiresUnblock() ) {
2653                         if ( $user->isBlockedFrom( $this, $useReplica ) ) {
2654                                 // @todo FIXME: Pass the relevant context into this function.
2655                                 $errors[] = $block->getPermissionsError( RequestContext::getMain() );
2656                         }
2657                 }
2658
2659                 return $errors;
2660         }
2661
2662         /**
2663          * Check that the user is allowed to read this page.
2664          *
2665          * @param string $action The action to check
2666          * @param User $user User to check
2667          * @param array $errors List of current errors
2668          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2669          * @param bool $short Short circuit on first error
2670          *
2671          * @return array List of errors
2672          */
2673         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2674                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2675
2676                 $whitelisted = false;
2677                 if ( User::isEveryoneAllowed( 'read' ) ) {
2678                         # Shortcut for public wikis, allows skipping quite a bit of code
2679                         $whitelisted = true;
2680                 } elseif ( $user->isAllowed( 'read' ) ) {
2681                         # If the user is allowed to read pages, he is allowed to read all pages
2682                         $whitelisted = true;
2683                 } elseif ( $this->isSpecial( 'Userlogin' )
2684                         || $this->isSpecial( 'PasswordReset' )
2685                         || $this->isSpecial( 'Userlogout' )
2686                 ) {
2687                         # Always grant access to the login page.
2688                         # Even anons need to be able to log in.
2689                         $whitelisted = true;
2690                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2691                         # Time to check the whitelist
2692                         # Only do these checks is there's something to check against
2693                         $name = $this->getPrefixedText();
2694                         $dbName = $this->getPrefixedDBkey();
2695
2696                         // Check for explicit whitelisting with and without underscores
2697                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2698                                 $whitelisted = true;
2699                         } elseif ( $this->mNamespace == NS_MAIN ) {
2700                                 # Old settings might have the title prefixed with
2701                                 # a colon for main-namespace pages
2702                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2703                                         $whitelisted = true;
2704                                 }
2705                         } elseif ( $this->isSpecialPage() ) {
2706                                 # If it's a special page, ditch the subpage bit and check again
2707                                 $name = $this->mDbkeyform;
2708                                 list( $name, /* $subpage */ ) =
2709                                         MediaWikiServices::getInstance()->getSpecialPageFactory()->
2710                                                 resolveAlias( $name );
2711                                 if ( $name ) {
2712                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2713                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2714                                                 $whitelisted = true;
2715                                         }
2716                                 }
2717                         }
2718                 }
2719
2720                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2721                         $name = $this->getPrefixedText();
2722                         // Check for regex whitelisting
2723                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2724                                 if ( preg_match( $listItem, $name ) ) {
2725                                         $whitelisted = true;
2726                                         break;
2727                                 }
2728                         }
2729                 }
2730
2731                 if ( !$whitelisted ) {
2732                         # If the title is not whitelisted, give extensions a chance to do so...
2733                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2734                         if ( !$whitelisted ) {
2735                                 $errors[] = $this->missingPermissionError( $action, $short );
2736                         }
2737                 }
2738
2739                 return $errors;
2740         }
2741
2742         /**
2743          * Get a description array when the user doesn't have the right to perform
2744          * $action (i.e. when User::isAllowed() returns false)
2745          *
2746          * @param string $action The action to check
2747          * @param bool $short Short circuit on first error
2748          * @return array Array containing an error message key and any parameters
2749          */
2750         private function missingPermissionError( $action, $short ) {
2751                 // We avoid expensive display logic for quickUserCan's and such
2752                 if ( $short ) {
2753                         return [ 'badaccess-group0' ];
2754                 }
2755
2756                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2757         }
2758
2759         /**
2760          * Can $user perform $action on this page? This is an internal function,
2761          * with multiple levels of checks depending on performance needs; see $rigor below.
2762          * It does not check wfReadOnly().
2763          *
2764          * @param string $action Action that permission needs to be checked for
2765          * @param User $user User to check
2766          * @param string $rigor One of (quick,full,secure)
2767          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2768          *   - full   : does cheap and expensive checks possibly from a replica DB
2769          *   - secure : does cheap and expensive checks, using the master as needed
2770          * @param bool $short Set this to true to stop after the first permission error.
2771          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2772          */
2773         protected function getUserPermissionsErrorsInternal(
2774                 $action, $user, $rigor = 'secure', $short = false
2775         ) {
2776                 if ( $rigor === true ) {
2777                         $rigor = 'secure'; // b/c
2778                 } elseif ( $rigor === false ) {
2779                         $rigor = 'quick'; // b/c
2780                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2781                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2782                 }
2783
2784                 # Read has special handling
2785                 if ( $action == 'read' ) {
2786                         $checks = [
2787                                 'checkPermissionHooks',
2788                                 'checkReadPermissions',
2789                                 'checkUserBlock', // for wgBlockDisablesLogin
2790                         ];
2791                 # Don't call checkSpecialsAndNSPermissions, checkSiteConfigPermissions
2792                 # or checkUserConfigPermissions here as it will lead to duplicate
2793                 # error messages. This is okay to do since anywhere that checks for
2794                 # create will also check for edit, and those checks are called for edit.
2795                 } elseif ( $action == 'create' ) {
2796                         $checks = [
2797                                 'checkQuickPermissions',
2798                                 'checkPermissionHooks',
2799                                 'checkPageRestrictions',
2800                                 'checkCascadingSourcesRestrictions',
2801                                 'checkActionPermissions',
2802                                 'checkUserBlock'
2803                         ];
2804                 } else {
2805                         $checks = [
2806                                 'checkQuickPermissions',
2807                                 'checkPermissionHooks',
2808                                 'checkSpecialsAndNSPermissions',
2809                                 'checkSiteConfigPermissions',
2810                                 'checkUserConfigPermissions',
2811                                 'checkPageRestrictions',
2812                                 'checkCascadingSourcesRestrictions',
2813                                 'checkActionPermissions',
2814                                 'checkUserBlock'
2815                         ];
2816                 }
2817
2818                 $errors = [];
2819                 foreach ( $checks as $method ) {
2820                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2821
2822                         if ( $short && $errors !== [] ) {
2823                                 break;
2824                         }
2825                 }
2826
2827                 return $errors;
2828         }
2829
2830         /**
2831          * Get a filtered list of all restriction types supported by this wiki.
2832          * @param bool $exists True to get all restriction types that apply to
2833          * titles that do exist, False for all restriction types that apply to
2834          * titles that do not exist
2835          * @return array
2836          */
2837         public static function getFilteredRestrictionTypes( $exists = true ) {
2838                 global $wgRestrictionTypes;
2839                 $types = $wgRestrictionTypes;
2840                 if ( $exists ) {
2841                         # Remove the create restriction for existing titles
2842                         $types = array_diff( $types, [ 'create' ] );
2843                 } else {
2844                         # Only the create and upload restrictions apply to non-existing titles
2845                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2846                 }
2847                 return $types;
2848         }
2849
2850         /**
2851          * Returns restriction types for the current Title
2852          *
2853          * @return array Applicable restriction types
2854          */
2855         public function getRestrictionTypes() {
2856                 if ( $this->isSpecialPage() ) {
2857                         return [];
2858                 }
2859
2860                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2861
2862                 if ( $this->mNamespace != NS_FILE ) {
2863                         # Remove the upload restriction for non-file titles
2864                         $types = array_diff( $types, [ 'upload' ] );
2865                 }
2866
2867                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2868
2869                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2870                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2871
2872                 return $types;
2873         }
2874
2875         /**
2876          * Is this title subject to title protection?
2877          * Title protection is the one applied against creation of such title.
2878          *
2879          * @return array|bool An associative array representing any existent title
2880          *   protection, or false if there's none.
2881          */
2882         public function getTitleProtection() {
2883                 $protection = $this->getTitleProtectionInternal();
2884                 if ( $protection ) {
2885                         if ( $protection['permission'] == 'sysop' ) {
2886                                 $protection['permission'] = 'editprotected'; // B/C
2887                         }
2888                         if ( $protection['permission'] == 'autoconfirmed' ) {
2889                                 $protection['permission'] = 'editsemiprotected'; // B/C
2890                         }
2891                 }
2892                 return $protection;
2893         }
2894
2895         /**
2896          * Fetch title protection settings
2897          *
2898          * To work correctly, $this->loadRestrictions() needs to have access to the
2899          * actual protections in the database without munging 'sysop' =>
2900          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2901          * callers probably want $this->getTitleProtection() instead.
2902          *
2903          * @return array|bool
2904          */
2905         protected function getTitleProtectionInternal() {
2906                 // Can't protect pages in special namespaces
2907                 if ( $this->mNamespace < 0 ) {
2908                         return false;
2909                 }
2910
2911                 // Can't protect pages that exist.
2912                 if ( $this->exists() ) {
2913                         return false;
2914                 }
2915
2916                 if ( $this->mTitleProtection === null ) {
2917                         $dbr = wfGetDB( DB_REPLICA );
2918                         $commentStore = CommentStore::getStore();
2919                         $commentQuery = $commentStore->getJoin( 'pt_reason' );
2920                         $res = $dbr->select(
2921                                 [ 'protected_titles' ] + $commentQuery['tables'],
2922                                 [
2923                                         'user' => 'pt_user',
2924                                         'expiry' => 'pt_expiry',
2925                                         'permission' => 'pt_create_perm'
2926                                 ] + $commentQuery['fields'],
2927                                 [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2928                                 __METHOD__,
2929                                 [],
2930                                 $commentQuery['joins']
2931                         );
2932
2933                         // fetchRow returns false if there are no rows.
2934                         $row = $dbr->fetchRow( $res );
2935                         if ( $row ) {
2936                                 $this->mTitleProtection = [
2937                                         'user' => $row['user'],
2938                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2939                                         'permission' => $row['permission'],
2940                                         'reason' => $commentStore->getComment( 'pt_reason', $row )->text,
2941                                 ];
2942                         } else {
2943                                 $this->mTitleProtection = false;
2944                         }
2945                 }
2946                 return $this->mTitleProtection;
2947         }
2948
2949         /**
2950          * Remove any title protection due to page existing
2951          */
2952         public function deleteTitleProtection() {
2953                 $dbw = wfGetDB( DB_MASTER );
2954
2955                 $dbw->delete(
2956                         'protected_titles',
2957                         [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2958                         __METHOD__
2959                 );
2960                 $this->mTitleProtection = false;
2961         }
2962
2963         /**
2964          * Is this page "semi-protected" - the *only* protection levels are listed
2965          * in $wgSemiprotectedRestrictionLevels?
2966          *
2967          * @param string $action Action to check (default: edit)
2968          * @return bool
2969          */
2970         public function isSemiProtected( $action = 'edit' ) {
2971                 global $wgSemiprotectedRestrictionLevels;
2972
2973                 $restrictions = $this->getRestrictions( $action );
2974                 $semi = $wgSemiprotectedRestrictionLevels;
2975                 if ( !$restrictions || !$semi ) {
2976                         // Not protected, or all protection is full protection
2977                         return false;
2978                 }
2979
2980                 // Remap autoconfirmed to editsemiprotected for BC
2981                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2982                         $semi[$key] = 'editsemiprotected';
2983                 }
2984                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2985                         $restrictions[$key] = 'editsemiprotected';
2986                 }
2987
2988                 return !array_diff( $restrictions, $semi );
2989         }
2990
2991         /**
2992          * Does the title correspond to a protected article?
2993          *
2994          * @param string $action The action the page is protected from,
2995          * by default checks all actions.
2996          * @return bool
2997          */
2998         public function isProtected( $action = '' ) {
2999                 global $wgRestrictionLevels;
3000
3001                 $restrictionTypes = $this->getRestrictionTypes();
3002
3003                 # Special pages have inherent protection
3004                 if ( $this->isSpecialPage() ) {
3005                         return true;
3006                 }
3007
3008                 # Check regular protection levels
3009                 foreach ( $restrictionTypes as $type ) {
3010                         if ( $action == $type || $action == '' ) {
3011                                 $r = $this->getRestrictions( $type );
3012                                 foreach ( $wgRestrictionLevels as $level ) {
3013                                         if ( in_array( $level, $r ) && $level != '' ) {
3014                                                 return true;
3015                                         }
3016                                 }
3017                         }
3018                 }
3019
3020                 return false;
3021         }
3022
3023         /**
3024          * Determines if $user is unable to edit this page because it has been protected
3025          * by $wgNamespaceProtection.
3026          *
3027          * @param User $user User object to check permissions
3028          * @return bool
3029          */
3030         public function isNamespaceProtected( User $user ) {
3031                 global $wgNamespaceProtection;
3032
3033                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
3034                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
3035                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
3036                                         return true;
3037                                 }
3038                         }
3039                 }
3040                 return false;
3041         }
3042
3043         /**
3044          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
3045          *
3046          * @return bool If the page is subject to cascading restrictions.
3047          */
3048         public function isCascadeProtected() {
3049                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
3050                 return ( $sources > 0 );
3051         }
3052
3053         /**
3054          * Determines whether cascading protection sources have already been loaded from
3055          * the database.
3056          *
3057          * @param bool $getPages True to check if the pages are loaded, or false to check
3058          * if the status is loaded.
3059          * @return bool Whether or not the specified information has been loaded
3060          * @since 1.23
3061          */
3062         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
3063                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
3064         }
3065
3066         /**
3067          * Cascading protection: Get the source of any cascading restrictions on this page.
3068          *
3069          * @param bool $getPages Whether or not to retrieve the actual pages
3070          *        that the restrictions have come from and the actual restrictions
3071          *        themselves.
3072          * @return array Two elements: First is an array of Title objects of the
3073          *        pages from which cascading restrictions have come, false for
3074          *        none, or true if such restrictions exist but $getPages was not
3075          *        set. Second is an array like that returned by
3076          *        Title::getAllRestrictions(), or an empty array if $getPages is
3077          *        false.
3078          */
3079         public function getCascadeProtectionSources( $getPages = true ) {
3080                 $pagerestrictions = [];
3081
3082                 if ( $this->mCascadeSources !== null && $getPages ) {
3083                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
3084                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
3085                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
3086                 }
3087
3088                 $dbr = wfGetDB( DB_REPLICA );
3089
3090                 if ( $this->mNamespace == NS_FILE ) {
3091                         $tables = [ 'imagelinks', 'page_restrictions' ];
3092                         $where_clauses = [
3093                                 'il_to' => $this->mDbkeyform,
3094                                 'il_from=pr_page',
3095                                 'pr_cascade' => 1
3096                         ];
3097                 } else {
3098                         $tables = [ 'templatelinks', 'page_restrictions' ];
3099                         $where_clauses = [
3100                                 'tl_namespace' => $this->mNamespace,
3101                                 'tl_title' => $this->mDbkeyform,
3102                                 'tl_from=pr_page',
3103                                 'pr_cascade' => 1
3104                         ];
3105                 }
3106
3107                 if ( $getPages ) {
3108                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
3109                                 'pr_expiry', 'pr_type', 'pr_level' ];
3110                         $where_clauses[] = 'page_id=pr_page';
3111                         $tables[] = 'page';
3112                 } else {
3113                         $cols = [ 'pr_expiry' ];
3114                 }
3115
3116                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
3117
3118                 $sources = $getPages ? [] : false;
3119                 $now = wfTimestampNow();
3120
3121                 foreach ( $res as $row ) {
3122                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3123                         if ( $expiry > $now ) {
3124                                 if ( $getPages ) {
3125                                         $page_id = $row->pr_page;
3126                                         $page_ns = $row->page_namespace;
3127                                         $page_title = $row->page_title;
3128                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
3129                                         # Add groups needed for each restriction type if its not already there
3130                                         # Make sure this restriction type still exists
3131
3132                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
3133                                                 $pagerestrictions[$row->pr_type] = [];
3134                                         }
3135
3136                                         if (
3137                                                 isset( $pagerestrictions[$row->pr_type] )
3138                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
3139                                         ) {
3140                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
3141                                         }
3142                                 } else {
3143                                         $sources = true;
3144                                 }
3145                         }
3146                 }
3147
3148                 if ( $getPages ) {
3149                         $this->mCascadeSources = $sources;
3150                         $this->mCascadingRestrictions = $pagerestrictions;
3151                 } else {
3152                         $this->mHasCascadingRestrictions = $sources;
3153                 }
3154
3155                 return [ $sources, $pagerestrictions ];
3156         }
3157
3158         /**
3159          * Accessor for mRestrictionsLoaded
3160          *
3161          * @return bool Whether or not the page's restrictions have already been
3162          * loaded from the database
3163          * @since 1.23
3164          */
3165         public function areRestrictionsLoaded() {
3166                 return $this->mRestrictionsLoaded;
3167         }
3168
3169         /**
3170          * Accessor/initialisation for mRestrictions
3171          *
3172          * @param string $action Action that permission needs to be checked for
3173          * @return array Restriction levels needed to take the action. All levels are
3174          *     required. Note that restriction levels are normally user rights, but 'sysop'
3175          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
3176          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
3177          */
3178         public function getRestrictions( $action ) {
3179                 if ( !$this->mRestrictionsLoaded ) {
3180                         $this->loadRestrictions();
3181                 }
3182                 return $this->mRestrictions[$action] ?? [];
3183         }
3184
3185         /**
3186          * Accessor/initialisation for mRestrictions
3187          *
3188          * @return array Keys are actions, values are arrays as returned by
3189          *     Title::getRestrictions()
3190          * @since 1.23
3191          */
3192         public function getAllRestrictions() {
3193                 if ( !$this->mRestrictionsLoaded ) {
3194                         $this->loadRestrictions();
3195                 }
3196                 return $this->mRestrictions;
3197         }
3198
3199         /**
3200          * Get the expiry time for the restriction against a given action
3201          *
3202          * @param string $action
3203          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3204          *     or not protected at all, or false if the action is not recognised.
3205          */
3206         public function getRestrictionExpiry( $action ) {
3207                 if ( !$this->mRestrictionsLoaded ) {
3208                         $this->loadRestrictions();
3209                 }
3210                 return $this->mRestrictionsExpiry[$action] ?? false;
3211         }
3212
3213         /**
3214          * Returns cascading restrictions for the current article
3215          *
3216          * @return bool
3217          */
3218         function areRestrictionsCascading() {
3219                 if ( !$this->mRestrictionsLoaded ) {
3220                         $this->loadRestrictions();
3221                 }
3222
3223                 return $this->mCascadeRestriction;
3224         }
3225
3226         /**
3227          * Compiles list of active page restrictions from both page table (pre 1.10)
3228          * and page_restrictions table for this existing page.
3229          * Public for usage by LiquidThreads.
3230          *
3231          * @param array $rows Array of db result objects
3232          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
3233          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3234          * Edit and move sections are separated by a colon
3235          * Example: "edit=autoconfirmed,sysop:move=sysop"
3236          */
3237         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3238                 // This function will only read rows from a table that we migrated away
3239                 // from before adding READ_LATEST support to loadRestrictions, so we
3240                 // don't need to support reading from DB_MASTER here.
3241                 $dbr = wfGetDB( DB_REPLICA );
3242
3243                 $restrictionTypes = $this->getRestrictionTypes();
3244
3245                 foreach ( $restrictionTypes as $type ) {
3246                         $this->mRestrictions[$type] = [];
3247                         $this->mRestrictionsExpiry[$type] = 'infinity';
3248                 }
3249
3250                 $this->mCascadeRestriction = false;
3251
3252                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3253                 if ( $oldFashionedRestrictions !== null ) {
3254                         $this->mOldRestrictions = $oldFashionedRestrictions;
3255                 }
3256
3257                 if ( $this->mOldRestrictions === false ) {
3258                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3259                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
3260                         $this->mOldRestrictions = $linkCache->getGoodLinkFieldObj( $this, 'restrictions' );
3261                 }
3262
3263                 if ( $this->mOldRestrictions != '' ) {
3264                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3265                                 $temp = explode( '=', trim( $restrict ) );
3266                                 if ( count( $temp ) == 1 ) {
3267                                         // old old format should be treated as edit/move restriction
3268                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3269                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3270                                 } else {
3271                                         $restriction = trim( $temp[1] );
3272                                         if ( $restriction != '' ) { // some old entries are empty
3273                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3274                                         }
3275                                 }
3276                         }
3277                 }
3278
3279                 if ( count( $rows ) ) {
3280                         # Current system - load second to make them override.
3281                         $now = wfTimestampNow();
3282
3283                         # Cycle through all the restrictions.
3284                         foreach ( $rows as $row ) {
3285                                 // Don't take care of restrictions types that aren't allowed
3286                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3287                                         continue;
3288                                 }
3289
3290                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3291
3292                                 // Only apply the restrictions if they haven't expired!
3293                                 if ( !$expiry || $expiry > $now ) {
3294                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3295                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3296
3297                                         $this->mCascadeRestriction |= $row->pr_cascade;
3298                                 }
3299                         }
3300                 }
3301
3302                 $this->mRestrictionsLoaded = true;
3303         }
3304
3305         /**
3306          * Load restrictions from the page_restrictions table
3307          *
3308          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
3309          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3310          * Edit and move sections are separated by a colon
3311          * Example: "edit=autoconfirmed,sysop:move=sysop"
3312          * @param int $flags A bit field. If self::READ_LATEST is set, skip replicas and read
3313          *  from the master DB.
3314          */
3315         public function loadRestrictions( $oldFashionedRestrictions = null, $flags = 0 ) {
3316                 $readLatest = DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST );
3317                 if ( $this->mRestrictionsLoaded && !$readLatest ) {
3318                         return;
3319                 }
3320
3321                 // TODO: should probably pass $flags into getArticleID, but it seems hacky
3322                 // to mix READ_LATEST and GAID_FOR_UPDATE, even if they have the same value.
3323                 // Maybe deprecate GAID_FOR_UPDATE now that we implement IDBAccessObject?
3324                 $id = $this->getArticleID();
3325                 if ( $id ) {
3326                         $fname = __METHOD__;
3327                         $loadRestrictionsFromDb = function ( Database $dbr ) use ( $fname, $id ) {
3328                                 return iterator_to_array(
3329                                         $dbr->select(
3330                                                 'page_restrictions',
3331                                                 [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3332                                                 [ 'pr_page' => $id ],
3333                                                 $fname
3334                                         )
3335                                 );
3336                         };
3337
3338                         if ( $readLatest ) {
3339                                 $dbr = wfGetDB( DB_MASTER );
3340                                 $rows = $loadRestrictionsFromDb( $dbr );
3341                         } else {
3342                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
3343                                 $rows = $cache->getWithSetCallback(
3344                                         // Page protections always leave a new null revision
3345                                         $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3346                                         $cache::TTL_DAY,
3347                                         function ( $curValue, &$ttl, array &$setOpts ) use ( $loadRestrictionsFromDb ) {
3348                                                 $dbr = wfGetDB( DB_REPLICA );
3349
3350                                                 $setOpts += Database::getCacheSetOptions( $dbr );
3351
3352                                                 return $loadRestrictionsFromDb( $dbr );
3353                                         }
3354                                 );
3355                         }
3356
3357                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3358                 } else {
3359                         $title_protection = $this->getTitleProtectionInternal();
3360
3361                         if ( $title_protection ) {
3362                                 $now = wfTimestampNow();
3363                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3364
3365                                 if ( !$expiry || $expiry > $now ) {
3366                                         // Apply the restrictions
3367                                         $this->mRestrictionsExpiry['create'] = $expiry;
3368                                         $this->mRestrictions['create'] =
3369                                                 explode( ',', trim( $title_protection['permission'] ) );
3370                                 } else { // Get rid of the old restrictions
3371                                         $this->mTitleProtection = false;
3372                                 }
3373                         } else {
3374                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3375                         }
3376                         $this->mRestrictionsLoaded = true;
3377                 }
3378         }
3379
3380         /**
3381          * Flush the protection cache in this object and force reload from the database.
3382          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3383          */
3384         public function flushRestrictions() {
3385                 $this->mRestrictionsLoaded = false;
3386                 $this->mTitleProtection = null;
3387         }
3388
3389         /**
3390          * Purge expired restrictions from the page_restrictions table
3391          *
3392          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3393          */
3394         static function purgeExpiredRestrictions() {
3395                 if ( wfReadOnly() ) {
3396                         return;
3397                 }
3398
3399                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3400                         wfGetDB( DB_MASTER ),
3401                         __METHOD__,
3402                         function ( IDatabase $dbw, $fname ) {
3403                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3404                                 $ids = $dbw->selectFieldValues(
3405                                         'page_restrictions',
3406                                         'pr_id',
3407                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3408                                         $fname,
3409                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3410                                 );
3411                                 if ( $ids ) {
3412                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3413                                 }
3414                         }
3415                 ) );
3416
3417                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3418                         wfGetDB( DB_MASTER ),
3419                         __METHOD__,
3420                         function ( IDatabase $dbw, $fname ) {
3421                                 $dbw->delete(
3422                                         'protected_titles',
3423                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3424                                         $fname
3425                                 );
3426                         }
3427                 ) );
3428         }
3429
3430         /**
3431          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3432          *
3433          * @return bool
3434          */
3435         public function hasSubpages() {
3436                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3437                         # Duh
3438                         return false;
3439                 }
3440
3441                 # We dynamically add a member variable for the purpose of this method
3442                 # alone to cache the result.  There's no point in having it hanging
3443                 # around uninitialized in every Title object; therefore we only add it
3444                 # if needed and don't declare it statically.
3445                 if ( $this->mHasSubpages === null ) {
3446                         $this->mHasSubpages = false;
3447                         $subpages = $this->getSubpages( 1 );
3448                         if ( $subpages instanceof TitleArray ) {
3449                                 $this->mHasSubpages = (bool)$subpages->count();
3450                         }
3451                 }
3452
3453                 return $this->mHasSubpages;
3454         }
3455
3456         /**
3457          * Get all subpages of this page.
3458          *
3459          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3460          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3461          *  doesn't allow subpages
3462          */
3463         public function getSubpages( $limit = -1 ) {
3464                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3465                         return [];
3466                 }
3467
3468                 $dbr = wfGetDB( DB_REPLICA );
3469                 $conds['page_namespace'] = $this->mNamespace;
3470                 $conds[] = 'page_title ' . $dbr->buildLike( $this->mDbkeyform . '/', $dbr->anyString() );
3471                 $options = [];
3472                 if ( $limit > -1 ) {
3473                         $options['LIMIT'] = $limit;
3474                 }
3475                 return TitleArray::newFromResult(
3476                         $dbr->select( 'page',
3477                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3478                                 $conds,
3479                                 __METHOD__,
3480                                 $options
3481                         )
3482                 );
3483         }
3484
3485         /**
3486          * Is there a version of this page in the deletion archive?
3487          *
3488          * @return int The number of archived revisions
3489          */
3490         public function isDeleted() {
3491                 if ( $this->mNamespace < 0 ) {
3492                         $n = 0;
3493                 } else {
3494                         $dbr = wfGetDB( DB_REPLICA );
3495
3496                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3497                                 [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3498                                 __METHOD__
3499                         );
3500                         if ( $this->mNamespace == NS_FILE ) {
3501                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3502                                         [ 'fa_name' => $this->mDbkeyform ],
3503                                         __METHOD__
3504                                 );
3505                         }
3506                 }
3507                 return (int)$n;
3508         }
3509
3510         /**
3511          * Is there a version of this page in the deletion archive?
3512          *
3513          * @return bool
3514          */
3515         public function isDeletedQuick() {
3516                 if ( $this->mNamespace < 0 ) {
3517                         return false;
3518                 }
3519                 $dbr = wfGetDB( DB_REPLICA );
3520                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3521                         [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3522                         __METHOD__
3523                 );
3524                 if ( !$deleted && $this->mNamespace == NS_FILE ) {
3525                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3526                                 [ 'fa_name' => $this->mDbkeyform ],
3527                                 __METHOD__
3528                         );
3529                 }
3530                 return $deleted;
3531         }
3532
3533         /**
3534          * Get the article ID for this Title from the link cache,
3535          * adding it if necessary
3536          *
3537          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3538          *  for update
3539          * @return int The ID
3540          */
3541         public function getArticleID( $flags = 0 ) {
3542                 if ( $this->mNamespace < 0 ) {
3543                         $this->mArticleID = 0;
3544                         return $this->mArticleID;
3545                 }
3546                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3547                 if ( $flags & self::GAID_FOR_UPDATE ) {
3548                         $oldUpdate = $linkCache->forUpdate( true );
3549                         $linkCache->clearLink( $this );
3550                         $this->mArticleID = $linkCache->addLinkObj( $this );
3551                         $linkCache->forUpdate( $oldUpdate );
3552                 } else {
3553                         if ( $this->mArticleID == -1 ) {
3554                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3555                         }
3556                 }
3557                 return $this->mArticleID;
3558         }
3559
3560         /**
3561          * Is this an article that is a redirect page?
3562          * Uses link cache, adding it if necessary
3563          *
3564          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3565          * @return bool
3566          */
3567         public function isRedirect( $flags = 0 ) {
3568                 if ( !is_null( $this->mRedirect ) ) {
3569                         return $this->mRedirect;
3570                 }
3571                 if ( !$this->getArticleID( $flags ) ) {
3572                         $this->mRedirect = false;
3573                         return $this->mRedirect;
3574                 }
3575
3576                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3577                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3578                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3579                 if ( $cached === null ) {
3580                         # Trust LinkCache's state over our own
3581                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3582                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3583                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3584                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3585                         # LinkCache to refresh its data from the master.
3586                         $this->mRedirect = false;
3587                         return $this->mRedirect;
3588                 }
3589
3590                 $this->mRedirect = (bool)$cached;
3591
3592                 return $this->mRedirect;
3593         }
3594
3595         /**
3596          * What is the length of this page?
3597          * Uses link cache, adding it if necessary
3598          *
3599          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3600          * @return int
3601          */
3602         public function getLength( $flags = 0 ) {
3603                 if ( $this->mLength != -1 ) {
3604                         return $this->mLength;
3605                 }
3606                 if ( !$this->getArticleID( $flags ) ) {
3607                         $this->mLength = 0;
3608                         return $this->mLength;
3609                 }
3610                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3611                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3612                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3613                 if ( $cached === null ) {
3614                         # Trust LinkCache's state over our own, as for isRedirect()
3615                         $this->mLength = 0;
3616                         return $this->mLength;
3617                 }
3618
3619                 $this->mLength = intval( $cached );
3620
3621                 return $this->mLength;
3622         }
3623
3624         /**
3625          * What is the page_latest field for this page?
3626          *
3627          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3628          * @return int Int or 0 if the page doesn't exist
3629          */
3630         public function getLatestRevID( $flags = 0 ) {
3631                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3632                         return intval( $this->mLatestID );
3633                 }
3634                 if ( !$this->getArticleID( $flags ) ) {
3635                         $this->mLatestID = 0;
3636                         return $this->mLatestID;
3637                 }
3638                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3639                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3640                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3641                 if ( $cached === null ) {
3642                         # Trust LinkCache's state over our own, as for isRedirect()
3643                         $this->mLatestID = 0;
3644                         return $this->mLatestID;
3645                 }
3646
3647                 $this->mLatestID = intval( $cached );
3648
3649                 return $this->mLatestID;
3650         }
3651
3652         /**
3653          * This clears some fields in this object, and clears any associated
3654          * keys in the "bad links" section of the link cache.
3655          *
3656          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3657          * loading of the new page_id. It's also called from
3658          * WikiPage::doDeleteArticleReal()
3659          *
3660          * @param int $newid The new Article ID
3661          */
3662         public function resetArticleID( $newid ) {
3663                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3664                 $linkCache->clearLink( $this );
3665
3666                 if ( $newid === false ) {
3667                         $this->mArticleID = -1;
3668                 } else {
3669                         $this->mArticleID = intval( $newid );
3670                 }
3671                 $this->mRestrictionsLoaded = false;
3672                 $this->mRestrictions = [];
3673                 $this->mOldRestrictions = false;
3674                 $this->mRedirect = null;
3675                 $this->mLength = -1;
3676                 $this->mLatestID = false;
3677                 $this->mContentModel = false;
3678                 $this->mEstimateRevisions = null;
3679                 $this->mPageLanguage = false;
3680                 $this->mDbPageLanguage = false;
3681                 $this->mIsBigDeletion = null;
3682         }
3683
3684         public static function clearCaches() {
3685                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3686                 $linkCache->clear();
3687
3688                 $titleCache = self::getTitleCache();
3689                 $titleCache->clear();
3690         }
3691
3692         /**
3693          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3694          *
3695          * @param string $text Containing title to capitalize
3696          * @param int $ns Namespace index, defaults to NS_MAIN
3697          * @return string Containing capitalized title
3698          */
3699         public static function capitalize( $text, $ns = NS_MAIN ) {
3700                 if ( MWNamespace::isCapitalized( $ns ) ) {
3701                         return MediaWikiServices::getInstance()->getContentLanguage()->ucfirst( $text );
3702                 } else {
3703                         return $text;
3704                 }
3705         }
3706
3707         /**
3708          * Secure and split - main initialisation function for this object
3709          *
3710          * Assumes that mDbkeyform has been set, and is urldecoded
3711          * and uses underscores, but not otherwise munged.  This function
3712          * removes illegal characters, splits off the interwiki and
3713          * namespace prefixes, sets the other forms, and canonicalizes
3714          * everything.
3715          *
3716          * @throws MalformedTitleException On invalid titles
3717          * @return bool True on success
3718          */
3719         private function secureAndSplit() {
3720                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3721                 //        the parsing code with Title, while avoiding massive refactoring.
3722                 // @todo: get rid of secureAndSplit, refactor parsing code.
3723                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3724                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3725                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3726                 // MalformedTitleException can be thrown here
3727                 $parts = $titleCodec->splitTitleString( $this->mDbkeyform, $this->mDefaultNamespace );
3728
3729                 # Fill fields
3730                 $this->setFragment( '#' . $parts['fragment'] );
3731                 $this->mInterwiki = $parts['interwiki'];
3732                 $this->mLocalInterwiki = $parts['local_interwiki'];
3733                 $this->mNamespace = $parts['namespace'];
3734                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3735
3736                 $this->mDbkeyform = $parts['dbkey'];
3737                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3738                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3739
3740                 # We already know that some pages won't be in the database!
3741                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3742                         $this->mArticleID = 0;
3743                 }
3744
3745                 return true;
3746         }
3747
3748         /**
3749          * Get an array of Title objects linking to this Title
3750          * Also stores the IDs in the link cache.
3751          *
3752          * WARNING: do not use this function on arbitrary user-supplied titles!
3753          * On heavily-used templates it will max out the memory.
3754          *
3755          * @param array $options May be FOR UPDATE
3756          * @param string $table Table name
3757          * @param string $prefix Fields prefix
3758          * @return Title[] Array of Title objects linking here
3759          */
3760         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3761                 if ( count( $options ) > 0 ) {
3762                         $db = wfGetDB( DB_MASTER );
3763                 } else {
3764                         $db = wfGetDB( DB_REPLICA );
3765                 }
3766
3767                 $res = $db->select(
3768                         [ 'page', $table ],
3769                         self::getSelectFields(),
3770                         [
3771                                 "{$prefix}_from=page_id",
3772                                 "{$prefix}_namespace" => $this->mNamespace,
3773                                 "{$prefix}_title" => $this->mDbkeyform ],
3774                         __METHOD__,
3775                         $options
3776                 );
3777
3778                 $retVal = [];
3779                 if ( $res->numRows() ) {
3780                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3781                         foreach ( $res as $row ) {
3782                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3783                                 if ( $titleObj ) {
3784                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3785                                         $retVal[] = $titleObj;
3786                                 }
3787                         }
3788                 }
3789                 return $retVal;
3790         }
3791
3792         /**
3793          * Get an array of Title objects using this Title as a template
3794          * Also stores the IDs in the link cache.
3795          *
3796          * WARNING: do not use this function on arbitrary user-supplied titles!
3797          * On heavily-used templates it will max out the memory.
3798          *
3799          * @param array $options Query option to Database::select()
3800          * @return Title[] Array of Title the Title objects linking here
3801          */
3802         public function getTemplateLinksTo( $options = [] ) {
3803                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3804         }
3805
3806         /**
3807          * Get an array of Title objects linked from this Title
3808          * Also stores the IDs in the link cache.
3809          *
3810          * WARNING: do not use this function on arbitrary user-supplied titles!
3811          * On heavily-used templates it will max out the memory.
3812          *
3813          * @param array $options Query option to Database::select()
3814          * @param string $table Table name
3815          * @param string $prefix Fields prefix
3816          * @return array Array of Title objects linking here
3817          */
3818         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3819                 $id = $this->getArticleID();
3820
3821                 # If the page doesn't exist; there can't be any link from this page
3822                 if ( !$id ) {
3823                         return [];
3824                 }
3825
3826                 $db = wfGetDB( DB_REPLICA );
3827
3828                 $blNamespace = "{$prefix}_namespace";
3829                 $blTitle = "{$prefix}_title";
3830
3831                 $pageQuery = WikiPage::getQueryInfo();
3832                 $res = $db->select(
3833                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3834                         array_merge(
3835                                 [ $blNamespace, $blTitle ],
3836                                 $pageQuery['fields']
3837                         ),
3838                         [ "{$prefix}_from" => $id ],
3839                         __METHOD__,
3840                         $options,
3841                         [ 'nestpage' => [
3842                                 'LEFT JOIN',
3843                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3844                         ] ] + $pageQuery['joins']
3845                 );
3846
3847                 $retVal = [];
3848                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3849                 foreach ( $res as $row ) {
3850                         if ( $row->page_id ) {
3851                                 $titleObj = self::newFromRow( $row );
3852                         } else {
3853                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3854                                 $linkCache->addBadLinkObj( $titleObj );
3855                         }
3856                         $retVal[] = $titleObj;
3857                 }
3858
3859                 return $retVal;
3860         }
3861
3862         /**
3863          * Get an array of Title objects used on this Title as a template
3864          * Also stores the IDs in the link cache.
3865          *
3866          * WARNING: do not use this function on arbitrary user-supplied titles!
3867          * On heavily-used templates it will max out the memory.
3868          *
3869          * @param array $options May be FOR UPDATE
3870          * @return Title[] Array of Title the Title objects used here
3871          */
3872         public function getTemplateLinksFrom( $options = [] ) {
3873                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3874         }
3875
3876         /**
3877          * Get an array of Title objects referring to non-existent articles linked
3878          * from this page.
3879          *
3880          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3881          *   should use redirect table in this case).
3882          * @return Title[] Array of Title the Title objects
3883          */
3884         public function getBrokenLinksFrom() {
3885                 if ( $this->getArticleID() == 0 ) {
3886                         # All links from article ID 0 are false positives
3887                         return [];
3888                 }
3889
3890                 $dbr = wfGetDB( DB_REPLICA );
3891                 $res = $dbr->select(
3892                         [ 'page', 'pagelinks' ],
3893                         [ 'pl_namespace', 'pl_title' ],
3894                         [
3895                                 'pl_from' => $this->getArticleID(),
3896                                 'page_namespace IS NULL'
3897                         ],
3898                         __METHOD__, [],
3899                         [
3900                                 'page' => [
3901                                         'LEFT JOIN',
3902                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3903                                 ]
3904                         ]
3905                 );
3906
3907                 $retVal = [];
3908                 foreach ( $res as $row ) {
3909                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3910                 }
3911                 return $retVal;
3912         }
3913
3914         /**
3915          * Get a list of URLs to purge from the CDN cache when this
3916          * page changes
3917          *
3918          * @return string[] Array of String the URLs
3919          */
3920         public function getCdnUrls() {
3921                 $urls = [
3922                         $this->getInternalURL(),
3923                         $this->getInternalURL( 'action=history' )
3924                 ];
3925
3926                 $pageLang = $this->getPageLanguage();
3927                 if ( $pageLang->hasVariants() ) {
3928                         $variants = $pageLang->getVariants();
3929                         foreach ( $variants as $vCode ) {
3930                                 $urls[] = $this->getInternalURL( $vCode );
3931                         }
3932                 }
3933
3934                 // If we are looking at a css/js user subpage, purge the action=raw.
3935                 if ( $this->isUserJsConfigPage() ) {
3936                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3937                 } elseif ( $this->isUserJsonConfigPage() ) {
3938                         $urls[] = $this->getInternalURL( 'action=raw&ctype=application/json' );
3939                 } elseif ( $this->isUserCssConfigPage() ) {
3940                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3941                 }
3942
3943                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3944                 return $urls;
3945         }
3946
3947         /**
3948          * Purge all applicable CDN URLs
3949          */
3950         public function purgeSquid() {
3951                 DeferredUpdates::addUpdate(
3952                         new CdnCacheUpdate( $this->getCdnUrls() ),
3953                         DeferredUpdates::PRESEND
3954                 );
3955         }
3956
3957         /**
3958          * Check whether a given move operation would be valid.
3959          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3960          *
3961          * @deprecated since 1.25, use MovePage's methods instead
3962          * @param Title &$nt The new title
3963          * @param bool $auth Whether to check user permissions (uses $wgUser)
3964          * @param string $reason Is the log summary of the move, used for spam checking
3965          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3966          */
3967         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3968                 global $wgUser;
3969
3970                 if ( !( $nt instanceof Title ) ) {
3971                         // Normally we'd add this to $errors, but we'll get
3972                         // lots of syntax errors if $nt is not an object
3973                         return [ [ 'badtitletext' ] ];
3974                 }
3975
3976                 $mp = new MovePage( $this, $nt );
3977                 $errors = $mp->isValidMove()->getErrorsArray();
3978                 if ( $auth ) {
3979                         $errors = wfMergeErrorArrays(
3980                                 $errors,
3981                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3982                         );
3983                 }
3984
3985                 return $errors ?: true;
3986         }
3987
3988         /**
3989          * Move a title to a new location
3990          *
3991          * @deprecated since 1.25, use the MovePage class instead
3992          * @param Title &$nt The new title
3993          * @param bool $auth Indicates whether $wgUser's permissions
3994          *  should be checked
3995          * @param string $reason The reason for the move
3996          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3997          *  Ignored if the user doesn't have the suppressredirect right.
3998          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3999          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
4000          */
4001         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
4002                 array $changeTags = []
4003         ) {
4004                 global $wgUser;
4005                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
4006                 if ( is_array( $err ) ) {
4007                         // Auto-block user's IP if the account was "hard" blocked
4008                         $wgUser->spreadAnyEditBlock();
4009                         return $err;
4010                 }
4011                 // Check suppressredirect permission
4012                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
4013                         $createRedirect = true;
4014                 }
4015
4016                 $mp = new MovePage( $this, $nt );
4017                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
4018                 if ( $status->isOK() ) {
4019                         return true;
4020                 } else {
4021                         return $status->getErrorsArray();
4022                 }
4023         }
4024
4025         /**
4026          * Move this page's subpages to be subpages of $nt
4027          *
4028          * @param Title $nt Move target
4029          * @param bool $auth Whether $wgUser's permissions should be checked
4030          * @param string $reason The reason for the move
4031          * @param bool $createRedirect Whether to create redirects from the old subpages to
4032          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4033          * @param array $changeTags Applied to the entry in the move log and redirect page revision
4034          * @return array Array with old page titles as keys, and strings (new page titles) or
4035          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
4036          *     getUserPermissionsErrors()-like error array with numeric indices if
4037          *     no pages were moved
4038          */
4039         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
4040                 array $changeTags = []
4041         ) {
4042                 global $wgMaximumMovedPages;
4043                 // Check permissions
4044                 if ( !$this->userCan( 'move-subpages' ) ) {
4045                         return [
4046                                 [ 'cant-move-subpages' ],
4047                         ];
4048                 }
4049                 // Do the source and target namespaces support subpages?
4050                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
4051                         return [
4052                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->mNamespace ) ],
4053                         ];
4054                 }
4055                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4056                         return [
4057                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
4058                         ];
4059                 }
4060
4061                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4062                 $retval = [];
4063                 $count = 0;
4064                 foreach ( $subpages as $oldSubpage ) {
4065                         $count++;
4066                         if ( $count > $wgMaximumMovedPages ) {
4067                                 $retval[$oldSubpage->getPrefixedText()] = [
4068                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
4069                                 ];
4070                                 break;
4071                         }
4072
4073                         // We don't know whether this function was called before
4074                         // or after moving the root page, so check both
4075                         // $this and $nt
4076                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4077                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4078                         ) {
4079                                 // When moving a page to a subpage of itself,
4080                                 // don't move it twice
4081                                 continue;
4082                         }
4083                         $newPageName = preg_replace(
4084                                         '#^' . preg_quote( $this->mDbkeyform, '#' ) . '#',
4085                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
4086                                         $oldSubpage->getDBkey() );
4087                         if ( $oldSubpage->isTalkPage() ) {
4088                                 $newNs = $nt->getTalkPage()->getNamespace();
4089                         } else {
4090                                 $newNs = $nt->getSubjectPage()->getNamespace();
4091                         }
4092                         # T16385: we need makeTitleSafe because the new page names may
4093                         # be longer than 255 characters.
4094                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
4095
4096                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
4097                         if ( $success === true ) {
4098                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4099                         } else {
4100                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4101                         }
4102                 }
4103                 return $retval;
4104         }
4105
4106         /**
4107          * Checks if this page is just a one-rev redirect.
4108          * Adds lock, so don't use just for light purposes.
4109          *
4110          * @return bool
4111          */
4112         public function isSingleRevRedirect() {
4113                 global $wgContentHandlerUseDB;
4114
4115                 $dbw = wfGetDB( DB_MASTER );
4116
4117                 # Is it a redirect?
4118                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
4119                 if ( $wgContentHandlerUseDB ) {
4120                         $fields[] = 'page_content_model';
4121                 }
4122
4123                 $row = $dbw->selectRow( 'page',
4124                         $fields,
4125                         $this->pageCond(),
4126                         __METHOD__,
4127                         [ 'FOR UPDATE' ]
4128                 );
4129                 # Cache some fields we may want
4130                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4131                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4132                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4133                 $this->mContentModel = $row && isset( $row->page_content_model )
4134                         ? strval( $row->page_content_model )
4135                         : false;
4136
4137                 if ( !$this->mRedirect ) {
4138                         return false;
4139                 }
4140                 # Does the article have a history?
4141                 $row = $dbw->selectField( [ 'page', 'revision' ],
4142                         'rev_id',
4143                         [ 'page_namespace' => $this->mNamespace,
4144                                 'page_title' => $this->mDbkeyform,
4145                                 'page_id=rev_page',
4146                                 'page_latest != rev_id'
4147                         ],
4148                         __METHOD__,
4149                         [ 'FOR UPDATE' ]
4150                 );
4151                 # Return true if there was no history
4152                 return ( $row === false );
4153         }
4154
4155         /**
4156          * Checks if $this can be moved to a given Title
4157          * - Selects for update, so don't call it unless you mean business
4158          *
4159          * @deprecated since 1.25, use MovePage's methods instead
4160          * @param Title $nt The new title to check
4161          * @return bool
4162          */
4163         public function isValidMoveTarget( $nt ) {
4164                 # Is it an existing file?
4165                 if ( $nt->getNamespace() == NS_FILE ) {
4166                         $file = wfLocalFile( $nt );
4167                         $file->load( File::READ_LATEST );
4168                         if ( $file->exists() ) {
4169                                 wfDebug( __METHOD__ . ": file exists\n" );
4170                                 return false;
4171                         }
4172                 }
4173                 # Is it a redirect with no history?
4174                 if ( !$nt->isSingleRevRedirect() ) {
4175                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4176                         return false;
4177                 }
4178                 # Get the article text
4179                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4180                 if ( !is_object( $rev ) ) {
4181                         return false;
4182                 }
4183                 $content = $rev->getContent();
4184                 # Does the redirect point to the source?
4185                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4186                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4187
4188                 if ( $redirTitle ) {
4189                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4190                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4191                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4192                                 return false;
4193                         } else {
4194                                 return true;
4195                         }
4196                 } else {
4197                         # Fail safe (not a redirect after all. strange.)
4198                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4199                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4200                         return false;
4201                 }
4202         }
4203
4204         /**
4205          * Get categories to which this Title belongs and return an array of
4206          * categories' names.
4207          *
4208          * @return array Array of parents in the form:
4209          *     $parent => $currentarticle
4210          */
4211         public function getParentCategories() {
4212                 $data = [];
4213
4214                 $titleKey = $this->getArticleID();
4215
4216                 if ( $titleKey === 0 ) {
4217                         return $data;
4218                 }
4219
4220                 $dbr = wfGetDB( DB_REPLICA );
4221
4222                 $res = $dbr->select(
4223                         'categorylinks',
4224                         'cl_to',
4225                         [ 'cl_from' => $titleKey ],
4226                         __METHOD__
4227                 );
4228
4229                 if ( $res->numRows() > 0 ) {
4230                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4231                         foreach ( $res as $row ) {
4232                                 // $data[] = Title::newFromText( $contLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4233                                 $data[$contLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] =
4234                                         $this->getFullText();
4235                         }
4236                 }
4237                 return $data;
4238         }
4239
4240         /**
4241          * Get a tree of parent categories
4242          *
4243          * @param array $children Array with the children in the keys, to check for circular refs
4244          * @return array Tree of parent categories
4245          */
4246         public function getParentCategoryTree( $children = [] ) {
4247                 $stack = [];
4248                 $parents = $this->getParentCategories();
4249
4250                 if ( $parents ) {
4251                         foreach ( $parents as $parent => $current ) {
4252                                 if ( array_key_exists( $parent, $children ) ) {
4253                                         # Circular reference
4254                                         $stack[$parent] = [];
4255                                 } else {
4256                                         $nt = self::newFromText( $parent );
4257                                         if ( $nt ) {
4258                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4259                                         }
4260                                 }
4261                         }
4262                 }
4263
4264                 return $stack;
4265         }
4266
4267         /**
4268          * Get an associative array for selecting this title from
4269          * the "page" table
4270          *
4271          * @return array Array suitable for the $where parameter of DB::select()
4272          */
4273         public function pageCond() {
4274                 if ( $this->mArticleID > 0 ) {
4275                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4276                         return [ 'page_id' => $this->mArticleID ];
4277                 } else {
4278                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4279                 }
4280         }
4281
4282         /**
4283          * Get next/previous revision ID relative to another revision ID
4284          * @param int $revId Revision ID. Get the revision that was before this one.
4285          * @param int $flags Title::GAID_FOR_UPDATE
4286          * @param string $dir 'next' or 'prev'
4287          * @return int|bool New revision ID, or false if none exists
4288          */
4289         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4290                 $revId = (int)$revId;
4291                 if ( $dir === 'next' ) {
4292                         $op = '>';
4293                         $sort = 'ASC';
4294                 } elseif ( $dir === 'prev' ) {
4295                         $op = '<';
4296                         $sort = 'DESC';
4297                 } else {
4298                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4299                 }
4300
4301                 if ( $flags & self::GAID_FOR_UPDATE ) {
4302                         $db = wfGetDB( DB_MASTER );
4303                 } else {
4304                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4305                 }
4306
4307                 // Intentionally not caring if the specified revision belongs to this
4308                 // page. We only care about the timestamp.
4309                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4310                 if ( $ts === false ) {
4311                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4312                         if ( $ts === false ) {
4313                                 // Or should this throw an InvalidArgumentException or something?
4314                                 return false;
4315                         }
4316                 }
4317                 $ts = $db->addQuotes( $ts );
4318
4319                 $revId = $db->selectField( 'revision', 'rev_id',
4320                         [
4321                                 'rev_page' => $this->getArticleID( $flags ),
4322                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4323                         ],
4324                         __METHOD__,
4325                         [
4326                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4327                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4328                         ]
4329                 );
4330
4331                 if ( $revId === false ) {
4332                         return false;
4333                 } else {
4334                         return intval( $revId );
4335                 }
4336         }
4337
4338         /**
4339          * Get the revision ID of the previous revision
4340          *
4341          * @param int $revId Revision ID. Get the revision that was before this one.
4342          * @param int $flags Title::GAID_FOR_UPDATE
4343          * @return int|bool Old revision ID, or false if none exists
4344          */
4345         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4346                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4347         }
4348
4349         /**
4350          * Get the revision ID of the next revision
4351          *
4352          * @param int $revId Revision ID. Get the revision that was after this one.
4353          * @param int $flags Title::GAID_FOR_UPDATE
4354          * @return int|bool Next revision ID, or false if none exists
4355          */
4356         public function getNextRevisionID( $revId, $flags = 0 ) {
4357                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4358         }
4359
4360         /**
4361          * Get the first revision of the page
4362          *
4363          * @param int $flags Title::GAID_FOR_UPDATE
4364          * @return Revision|null If page doesn't exist
4365          */
4366         public function getFirstRevision( $flags = 0 ) {
4367                 $pageId = $this->getArticleID( $flags );
4368                 if ( $pageId ) {
4369                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4370                         $revQuery = Revision::getQueryInfo();
4371                         $row = $db->selectRow( $revQuery['tables'], $revQuery['fields'],
4372                                 [ 'rev_page' => $pageId ],
4373                                 __METHOD__,
4374                                 [
4375                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4376                                         'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
4377                                 ],
4378                                 $revQuery['joins']
4379                         );
4380                         if ( $row ) {
4381                                 return new Revision( $row, 0, $this );
4382                         }
4383                 }
4384                 return null;
4385         }
4386
4387         /**
4388          * Get the oldest revision timestamp of this page
4389          *
4390          * @param int $flags Title::GAID_FOR_UPDATE
4391          * @return string|null MW timestamp
4392          */
4393         public function getEarliestRevTime( $flags = 0 ) {
4394                 $rev = $this->getFirstRevision( $flags );
4395                 return $rev ? $rev->getTimestamp() : null;
4396         }
4397
4398         /**
4399          * Check if this is a new page
4400          *
4401          * @return bool
4402          */
4403         public function isNewPage() {
4404                 $dbr = wfGetDB( DB_REPLICA );
4405                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4406         }
4407
4408         /**
4409          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4410          *
4411          * @return bool
4412          */
4413         public function isBigDeletion() {
4414                 global $wgDeleteRevisionsLimit;
4415
4416                 if ( !$wgDeleteRevisionsLimit ) {
4417                         return false;
4418                 }
4419
4420                 if ( $this->mIsBigDeletion === null ) {
4421                         $dbr = wfGetDB( DB_REPLICA );
4422
4423                         $revCount = $dbr->selectRowCount(
4424                                 'revision',
4425                                 '1',
4426                                 [ 'rev_page' => $this->getArticleID() ],
4427                                 __METHOD__,
4428                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4429                         );
4430
4431                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4432                 }
4433
4434                 return $this->mIsBigDeletion;
4435         }
4436
4437         /**
4438          * Get the approximate revision count of this page.
4439          *
4440          * @return int
4441          */
4442         public function estimateRevisionCount() {
4443                 if ( !$this->exists() ) {
4444                         return 0;
4445                 }
4446
4447                 if ( $this->mEstimateRevisions === null ) {
4448                         $dbr = wfGetDB( DB_REPLICA );
4449                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4450                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4451                 }
4452
4453                 return $this->mEstimateRevisions;
4454         }
4455
4456         /**
4457          * Get the number of revisions between the given revision.
4458          * Used for diffs and other things that really need it.
4459          *
4460          * @param int|Revision $old Old revision or rev ID (first before range)
4461          * @param int|Revision $new New revision or rev ID (first after range)
4462          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4463          * @return int Number of revisions between these revisions.
4464          */
4465         public function countRevisionsBetween( $old, $new, $max = null ) {
4466                 if ( !( $old instanceof Revision ) ) {
4467                         $old = Revision::newFromTitle( $this, (int)$old );
4468                 }
4469                 if ( !( $new instanceof Revision ) ) {
4470                         $new = Revision::newFromTitle( $this, (int)$new );
4471                 }
4472                 if ( !$old || !$new ) {
4473                         return 0; // nothing to compare
4474                 }
4475                 $dbr = wfGetDB( DB_REPLICA );
4476                 $conds = [
4477                         'rev_page' => $this->getArticleID(),
4478                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4479                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4480                 ];
4481                 if ( $max !== null ) {
4482                         return $dbr->selectRowCount( 'revision', '1',
4483                                 $conds,
4484                                 __METHOD__,
4485                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4486                         );
4487                 } else {
4488                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4489                 }
4490         }
4491
4492         /**
4493          * Get the authors between the given revisions or revision IDs.
4494          * Used for diffs and other things that really need it.
4495          *
4496          * @since 1.23
4497          *
4498          * @param int|Revision $old Old revision or rev ID (first before range by default)
4499          * @param int|Revision $new New revision or rev ID (first after range by default)
4500          * @param int $limit Maximum number of authors
4501          * @param string|array $options (Optional): Single option, or an array of options:
4502          *     'include_old' Include $old in the range; $new is excluded.
4503          *     'include_new' Include $new in the range; $old is excluded.
4504          *     'include_both' Include both $old and $new in the range.
4505          *     Unknown option values are ignored.
4506          * @return array|null Names of revision authors in the range; null if not both revisions exist
4507          */
4508         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4509                 if ( !( $old instanceof Revision ) ) {
4510                         $old = Revision::newFromTitle( $this, (int)$old );
4511                 }
4512                 if ( !( $new instanceof Revision ) ) {
4513                         $new = Revision::newFromTitle( $this, (int)$new );
4514                 }
4515                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4516                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4517                 // in the sanity check below?
4518                 if ( !$old || !$new ) {
4519                         return null; // nothing to compare
4520                 }
4521                 $authors = [];
4522                 $old_cmp = '>';
4523                 $new_cmp = '<';
4524                 $options = (array)$options;
4525                 if ( in_array( 'include_old', $options ) ) {
4526                         $old_cmp = '>=';
4527                 }
4528                 if ( in_array( 'include_new', $options ) ) {
4529                         $new_cmp = '<=';
4530                 }
4531                 if ( in_array( 'include_both', $options ) ) {
4532                         $old_cmp = '>=';
4533                         $new_cmp = '<=';
4534                 }
4535                 // No DB query needed if $old and $new are the same or successive revisions:
4536                 if ( $old->getId() === $new->getId() ) {
4537                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4538                                 [] :
4539                                 [ $old->getUserText( Revision::RAW ) ];
4540                 } elseif ( $old->getId() === $new->getParentId() ) {
4541                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4542                                 $authors[] = $old->getUserText( Revision::RAW );
4543                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4544                                         $authors[] = $new->getUserText( Revision::RAW );
4545                                 }
4546                         } elseif ( $old_cmp === '>=' ) {
4547                                 $authors[] = $old->getUserText( Revision::RAW );
4548                         } elseif ( $new_cmp === '<=' ) {
4549                                 $authors[] = $new->getUserText( Revision::RAW );
4550                         }
4551                         return $authors;
4552                 }
4553                 $dbr = wfGetDB( DB_REPLICA );
4554                 $revQuery = Revision::getQueryInfo();
4555                 $authors = $dbr->selectFieldValues(
4556                         $revQuery['tables'],
4557                         $revQuery['fields']['rev_user_text'],
4558                         [
4559                                 'rev_page' => $this->getArticleID(),
4560                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4561                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4562                         ], __METHOD__,
4563                         [ 'DISTINCT', 'LIMIT' => $limit + 1 ], // add one so caller knows it was truncated
4564                         $revQuery['joins']
4565                 );
4566                 return $authors;
4567         }
4568
4569         /**
4570          * Get the number of authors between the given revisions or revision IDs.
4571          * Used for diffs and other things that really need it.
4572          *
4573          * @param int|Revision $old Old revision or rev ID (first before range by default)
4574          * @param int|Revision $new New revision or rev ID (first after range by default)
4575          * @param int $limit Maximum number of authors
4576          * @param string|array $options (Optional): Single option, or an array of options:
4577          *     'include_old' Include $old in the range; $new is excluded.
4578          *     'include_new' Include $new in the range; $old is excluded.
4579          *     'include_both' Include both $old and $new in the range.
4580          *     Unknown option values are ignored.
4581          * @return int Number of revision authors in the range; zero if not both revisions exist
4582          */
4583         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4584                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4585                 return $authors ? count( $authors ) : 0;
4586         }
4587
4588         /**
4589          * Compare with another title.
4590          *
4591          * @param Title $title
4592          * @return bool
4593          */
4594         public function equals( Title $title ) {
4595                 // Note: === is necessary for proper matching of number-like titles.
4596                 return $this->mInterwiki === $title->mInterwiki
4597                         && $this->mNamespace == $title->mNamespace
4598                         && $this->mDbkeyform === $title->mDbkeyform;
4599         }
4600
4601         /**
4602          * Check if this title is a subpage of another title
4603          *
4604          * @param Title $title
4605          * @return bool
4606          */
4607         public function isSubpageOf( Title $title ) {
4608                 return $this->mInterwiki === $title->mInterwiki
4609                         && $this->mNamespace == $title->mNamespace
4610                         && strpos( $this->mDbkeyform, $title->mDbkeyform . '/' ) === 0;
4611         }
4612
4613         /**
4614          * Check if page exists.  For historical reasons, this function simply
4615          * checks for the existence of the title in the page table, and will
4616          * thus return false for interwiki links, special pages and the like.
4617          * If you want to know if a title can be meaningfully viewed, you should
4618          * probably call the isKnown() method instead.
4619          *
4620          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4621          *   from master/for update
4622          * @return bool
4623          */
4624         public function exists( $flags = 0 ) {
4625                 $exists = $this->getArticleID( $flags ) != 0;
4626                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4627                 return $exists;
4628         }
4629
4630         /**
4631          * Should links to this title be shown as potentially viewable (i.e. as
4632          * "bluelinks"), even if there's no record by this title in the page
4633          * table?
4634          *
4635          * This function is semi-deprecated for public use, as well as somewhat
4636          * misleadingly named.  You probably just want to call isKnown(), which
4637          * calls this function internally.
4638          *
4639          * (ISSUE: Most of these checks are cheap, but the file existence check
4640          * can potentially be quite expensive.  Including it here fixes a lot of
4641          * existing code, but we might want to add an optional parameter to skip
4642          * it and any other expensive checks.)
4643          *
4644          * @return bool
4645          */
4646         public function isAlwaysKnown() {
4647                 $isKnown = null;
4648
4649                 /**
4650                  * Allows overriding default behavior for determining if a page exists.
4651                  * If $isKnown is kept as null, regular checks happen. If it's
4652                  * a boolean, this value is returned by the isKnown method.
4653                  *
4654                  * @since 1.20
4655                  *
4656                  * @param Title $title
4657                  * @param bool|null $isKnown
4658                  */
4659                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4660
4661                 if ( !is_null( $isKnown ) ) {
4662                         return $isKnown;
4663                 }
4664
4665                 if ( $this->isExternal() ) {
4666                         return true; // any interwiki link might be viewable, for all we know
4667                 }
4668
4669                 switch ( $this->mNamespace ) {
4670                         case NS_MEDIA:
4671                         case NS_FILE:
4672                                 // file exists, possibly in a foreign repo
4673                                 return (bool)wfFindFile( $this );
4674                         case NS_SPECIAL:
4675                                 // valid special page
4676                                 return MediaWikiServices::getInstance()->getSpecialPageFactory()->
4677                                         exists( $this->mDbkeyform );
4678                         case NS_MAIN:
4679                                 // selflink, possibly with fragment
4680                                 return $this->mDbkeyform == '';
4681                         case NS_MEDIAWIKI:
4682                                 // known system message
4683                                 return $this->hasSourceText() !== false;
4684                         default:
4685                                 return false;
4686                 }
4687         }
4688
4689         /**
4690          * Does this title refer to a page that can (or might) be meaningfully
4691          * viewed?  In particular, this function may be used to determine if
4692          * links to the title should be rendered as "bluelinks" (as opposed to
4693          * "redlinks" to non-existent pages).
4694          * Adding something else to this function will cause inconsistency
4695          * since LinkHolderArray calls isAlwaysKnown() and does its own
4696          * page existence check.
4697          *
4698          * @return bool
4699          */
4700         public function isKnown() {
4701                 return $this->isAlwaysKnown() || $this->exists();
4702         }
4703
4704         /**
4705          * Does this page have source text?
4706          *
4707          * @return bool
4708          */
4709         public function hasSourceText() {
4710                 if ( $this->exists() ) {
4711                         return true;
4712                 }
4713
4714                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4715                         // If the page doesn't exist but is a known system message, default
4716                         // message content will be displayed, same for language subpages-
4717                         // Use always content language to avoid loading hundreds of languages
4718                         // to get the link color.
4719                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4720                         list( $name, ) = MessageCache::singleton()->figureMessage(
4721                                 $contLang->lcfirst( $this->getText() )
4722                         );
4723                         $message = wfMessage( $name )->inLanguage( $contLang )->useDatabase( false );
4724                         return $message->exists();
4725                 }
4726
4727                 return false;
4728         }
4729
4730         /**
4731          * Get the default (plain) message contents for an page that overrides an
4732          * interface message key.
4733          *
4734          * Primary use cases:
4735          *
4736          * - Article:
4737          *    - Show default when viewing the page. The Article::getSubstituteContent
4738          *      method displays the default message content, instead of the
4739          *      'noarticletext' placeholder message normally used.
4740          *
4741          * - EditPage:
4742          *    - Title of edit page. When creating an interface message override,
4743          *      the editor is told they are "Editing the page", instead of
4744          *      "Creating the page". (EditPage::setHeaders)
4745          *    - Edit notice. The 'translateinterface' edit notice is shown when creating
4746          *      or editing a an interface message override. (EditPage::showIntro)
4747          *    - Opening the editor. The contents of the localisation message are used
4748          *      as contents of the editor when creating a new page in the MediaWiki
4749          *      namespace. This simplifies the process for editors when "changing"
4750          *      an interface message by creating an override. (EditPage::getContentObject)
4751          *    - Showing a diff. The left-hand side of a diff when an editor is
4752          *      previewing their changes before saving the creation of a page in the
4753          *      MediaWiki namespace. (EditPage::showDiff)
4754          *    - Disallowing a save. When attempting to create a a MediaWiki-namespace
4755          *      page with the proposed content matching the interface message default,
4756          *      the save is rejected, the same way we disallow blank pages from being
4757          *      created. (EditPage::internalAttemptSave)
4758          *
4759          * - ApiEditPage:
4760          *    - Default content, when using the 'prepend' or 'append' feature.
4761          *
4762          * - SkinTemplate:
4763          *    - Label the create action as "Edit", if the page can be an override.
4764          *
4765          * @return string|bool
4766          */
4767         public function getDefaultMessageText() {
4768                 if ( $this->mNamespace != NS_MEDIAWIKI ) { // Just in case
4769                         return false;
4770                 }
4771
4772                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4773                         MediaWikiServices::getInstance()->getContentLanguage()->lcfirst( $this->getText() )
4774                 );
4775                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4776
4777                 if ( $message->exists() ) {
4778                         return $message->plain();
4779                 } else {
4780                         return false;
4781                 }
4782         }
4783
4784         /**
4785          * Updates page_touched for this page; called from LinksUpdate.php
4786          *
4787          * @param string|null $purgeTime [optional] TS_MW timestamp
4788          * @return bool True if the update succeeded
4789          */
4790         public function invalidateCache( $purgeTime = null ) {
4791                 if ( wfReadOnly() ) {
4792                         return false;
4793                 } elseif ( $this->mArticleID === 0 ) {
4794                         return true; // avoid gap locking if we know it's not there
4795                 }
4796
4797                 $dbw = wfGetDB( DB_MASTER );
4798                 $dbw->onTransactionPreCommitOrIdle(
4799                         function () use ( $dbw ) {
4800                                 ResourceLoaderWikiModule::invalidateModuleCache(
4801                                         $this, null, null, $dbw->getDomainId() );
4802                         },
4803                         __METHOD__
4804                 );
4805
4806                 $conds = $this->pageCond();
4807                 DeferredUpdates::addUpdate(
4808                         new AutoCommitUpdate(
4809                                 $dbw,
4810                                 __METHOD__,
4811                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4812                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4813                                         $dbw->update(
4814                                                 'page',
4815                                                 [ 'page_touched' => $dbTimestamp ],
4816                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4817                                                 $fname
4818                                         );
4819                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4820                                 }
4821                         ),
4822                         DeferredUpdates::PRESEND
4823                 );
4824
4825                 return true;
4826         }
4827
4828         /**
4829          * Update page_touched timestamps and send CDN purge messages for
4830          * pages linking to this title. May be sent to the job queue depending
4831          * on the number of links. Typically called on create and delete.
4832          */
4833         public function touchLinks() {
4834                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4835                 if ( $this->mNamespace == NS_CATEGORY ) {
4836                         DeferredUpdates::addUpdate(
4837                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4838                         );
4839                 }
4840         }
4841
4842         /**
4843          * Get the last touched timestamp
4844          *
4845          * @param IDatabase|null $db
4846          * @return string|false Last-touched timestamp
4847          */
4848         public function getTouched( $db = null ) {
4849                 if ( $db === null ) {
4850                         $db = wfGetDB( DB_REPLICA );
4851                 }
4852                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4853                 return $touched;
4854         }
4855
4856         /**
4857          * Get the timestamp when this page was updated since the user last saw it.
4858          *
4859          * @param User|null $user
4860          * @return string|null
4861          */
4862         public function getNotificationTimestamp( $user = null ) {
4863                 global $wgUser;
4864
4865                 // Assume current user if none given
4866                 if ( !$user ) {
4867                         $user = $wgUser;
4868                 }
4869                 // Check cache first
4870                 $uid = $user->getId();
4871                 if ( !$uid ) {
4872                         return false;
4873                 }
4874                 // avoid isset here, as it'll return false for null entries
4875                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4876                         return $this->mNotificationTimestamp[$uid];
4877                 }
4878                 // Don't cache too much!
4879                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4880                         $this->mNotificationTimestamp = [];
4881                 }
4882
4883                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4884                 $watchedItem = $store->getWatchedItem( $user, $this );
4885                 if ( $watchedItem ) {
4886                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4887                 } else {
4888                         $this->mNotificationTimestamp[$uid] = false;
4889                 }
4890
4891                 return $this->mNotificationTimestamp[$uid];
4892         }
4893
4894         /**
4895          * Generate strings used for xml 'id' names in monobook tabs
4896          *
4897          * @param string $prepend Defaults to 'nstab-'
4898          * @return string XML 'id' name
4899          */
4900         public function getNamespaceKey( $prepend = 'nstab-' ) {
4901                 // Gets the subject namespace of this title
4902                 $subjectNS = MWNamespace::getSubject( $this->mNamespace );
4903                 // Prefer canonical namespace name for HTML IDs
4904                 $namespaceKey = MWNamespace::getCanonicalName( $subjectNS );
4905                 if ( $namespaceKey === false ) {
4906                         // Fallback to localised text
4907                         $namespaceKey = $this->getSubjectNsText();
4908                 }
4909                 // Makes namespace key lowercase
4910                 $namespaceKey = MediaWikiServices::getInstance()->getContentLanguage()->lc( $namespaceKey );
4911                 // Uses main
4912                 if ( $namespaceKey == '' ) {
4913                         $namespaceKey = 'main';
4914                 }
4915                 // Changes file to image for backwards compatibility
4916                 if ( $namespaceKey == 'file' ) {
4917                         $namespaceKey = 'image';
4918                 }
4919                 return $prepend . $namespaceKey;
4920         }
4921
4922         /**
4923          * Get all extant redirects to this Title
4924          *
4925          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4926          * @return Title[] Array of Title redirects to this title
4927          */
4928         public function getRedirectsHere( $ns = null ) {
4929                 $redirs = [];
4930
4931                 $dbr = wfGetDB( DB_REPLICA );
4932                 $where = [
4933                         'rd_namespace' => $this->mNamespace,
4934                         'rd_title' => $this->mDbkeyform,
4935                         'rd_from = page_id'
4936                 ];
4937                 if ( $this->isExternal() ) {
4938                         $where['rd_interwiki'] = $this->mInterwiki;
4939                 } else {
4940                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4941                 }
4942                 if ( !is_null( $ns ) ) {
4943                         $where['page_namespace'] = $ns;
4944                 }
4945
4946                 $res = $dbr->select(
4947                         [ 'redirect', 'page' ],
4948                         [ 'page_namespace', 'page_title' ],
4949                         $where,
4950                         __METHOD__
4951                 );
4952
4953                 foreach ( $res as $row ) {
4954                         $redirs[] = self::newFromRow( $row );
4955                 }
4956                 return $redirs;
4957         }
4958
4959         /**
4960          * Check if this Title is a valid redirect target
4961          *
4962          * @return bool
4963          */
4964         public function isValidRedirectTarget() {
4965                 global $wgInvalidRedirectTargets;
4966
4967                 if ( $this->isSpecialPage() ) {
4968                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4969                         if ( $this->isSpecial( 'Userlogout' ) ) {
4970                                 return false;
4971                         }
4972
4973                         foreach ( $wgInvalidRedirectTargets as $target ) {
4974                                 if ( $this->isSpecial( $target ) ) {
4975                                         return false;
4976                                 }
4977                         }
4978                 }
4979
4980                 return true;
4981         }
4982
4983         /**
4984          * Get a backlink cache object
4985          *
4986          * @return BacklinkCache
4987          */
4988         public function getBacklinkCache() {
4989                 return BacklinkCache::get( $this );
4990         }
4991
4992         /**
4993          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4994          *
4995          * @return bool
4996          */
4997         public function canUseNoindex() {
4998                 global $wgExemptFromUserRobotsControl;
4999
5000                 $bannedNamespaces = $wgExemptFromUserRobotsControl ?? MWNamespace::getContentNamespaces();
5001
5002                 return !in_array( $this->mNamespace, $bannedNamespaces );
5003         }
5004
5005         /**
5006          * Returns the raw sort key to be used for categories, with the specified
5007          * prefix.  This will be fed to Collation::getSortKey() to get a
5008          * binary sortkey that can be used for actual sorting.
5009          *
5010          * @param string $prefix The prefix to be used, specified using
5011          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
5012          *   prefix.
5013          * @return string
5014          */
5015         public function getCategorySortkey( $prefix = '' ) {
5016                 $unprefixed = $this->getText();
5017
5018                 // Anything that uses this hook should only depend
5019                 // on the Title object passed in, and should probably
5020                 // tell the users to run updateCollations.php --force
5021                 // in order to re-sort existing category relations.
5022                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
5023                 if ( $prefix !== '' ) {
5024                         # Separate with a line feed, so the unprefixed part is only used as
5025                         # a tiebreaker when two pages have the exact same prefix.
5026                         # In UCA, tab is the only character that can sort above LF
5027                         # so we strip both of them from the original prefix.
5028                         $prefix = strtr( $prefix, "\n\t", '  ' );
5029                         return "$prefix\n$unprefixed";
5030                 }
5031                 return $unprefixed;
5032         }
5033
5034         /**
5035          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
5036          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
5037          * the db, it will return NULL.
5038          *
5039          * @return string|null|bool
5040          */
5041         private function getDbPageLanguageCode() {
5042                 global $wgPageLanguageUseDB;
5043
5044                 // check, if the page language could be saved in the database, and if so and
5045                 // the value is not requested already, lookup the page language using LinkCache
5046                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
5047                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
5048                         $linkCache->addLinkObj( $this );
5049                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
5050                 }
5051
5052                 return $this->mDbPageLanguage;
5053         }
5054
5055         /**
5056          * Get the language in which the content of this page is written in
5057          * wikitext. Defaults to content language, but in certain cases it can be
5058          * e.g. $wgLang (such as special pages, which are in the user language).
5059          *
5060          * @since 1.18
5061          * @return Language
5062          */
5063         public function getPageLanguage() {
5064                 global $wgLang, $wgLanguageCode;
5065                 if ( $this->isSpecialPage() ) {
5066                         // special pages are in the user language
5067                         return $wgLang;
5068                 }
5069
5070                 // Checking if DB language is set
5071                 $dbPageLanguage = $this->getDbPageLanguageCode();
5072                 if ( $dbPageLanguage ) {
5073                         return wfGetLangObj( $dbPageLanguage );
5074                 }
5075
5076                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
5077                         // Note that this may depend on user settings, so the cache should
5078                         // be only per-request.
5079                         // NOTE: ContentHandler::getPageLanguage() may need to load the
5080                         // content to determine the page language!
5081                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
5082                         // tests.
5083                         $contentHandler = ContentHandler::getForTitle( $this );
5084                         $langObj = $contentHandler->getPageLanguage( $this );
5085                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
5086                 } else {
5087                         $langObj = Language::factory( $this->mPageLanguage[0] );
5088                 }
5089
5090                 return $langObj;
5091         }
5092
5093         /**
5094          * Get the language in which the content of this page is written when
5095          * viewed by user. Defaults to content language, but in certain cases it can be
5096          * e.g. $wgLang (such as special pages, which are in the user language).
5097          *
5098          * @since 1.20
5099          * @return Language
5100          */
5101         public function getPageViewLanguage() {
5102                 global $wgLang;
5103
5104                 if ( $this->isSpecialPage() ) {
5105                         // If the user chooses a variant, the content is actually
5106                         // in a language whose code is the variant code.
5107                         $variant = $wgLang->getPreferredVariant();
5108                         if ( $wgLang->getCode() !== $variant ) {
5109                                 return Language::factory( $variant );
5110                         }
5111
5112                         return $wgLang;
5113                 }
5114
5115                 // Checking if DB language is set
5116                 $dbPageLanguage = $this->getDbPageLanguageCode();
5117                 if ( $dbPageLanguage ) {
5118                         $pageLang = wfGetLangObj( $dbPageLanguage );
5119                         $variant = $pageLang->getPreferredVariant();
5120                         if ( $pageLang->getCode() !== $variant ) {
5121                                 $pageLang = Language::factory( $variant );
5122                         }
5123
5124                         return $pageLang;
5125                 }
5126
5127                 // @note Can't be cached persistently, depends on user settings.
5128                 // @note ContentHandler::getPageViewLanguage() may need to load the
5129                 //   content to determine the page language!
5130                 $contentHandler = ContentHandler::getForTitle( $this );
5131                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5132                 return $pageLang;
5133         }
5134
5135         /**
5136          * Get a list of rendered edit notices for this page.
5137          *
5138          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5139          * they will already be wrapped in paragraphs.
5140          *
5141          * @since 1.21
5142          * @param int $oldid Revision ID that's being edited
5143          * @return array
5144          */
5145         public function getEditNotices( $oldid = 0 ) {
5146                 $notices = [];
5147
5148                 // Optional notice for the entire namespace
5149                 $editnotice_ns = 'editnotice-' . $this->mNamespace;
5150                 $msg = wfMessage( $editnotice_ns );
5151                 if ( $msg->exists() ) {
5152                         $html = $msg->parseAsBlock();
5153                         // Edit notices may have complex logic, but output nothing (T91715)
5154                         if ( trim( $html ) !== '' ) {
5155                                 $notices[$editnotice_ns] = Html::rawElement(
5156                                         'div',
5157                                         [ 'class' => [
5158                                                 'mw-editnotice',
5159                                                 'mw-editnotice-namespace',
5160                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
5161                                         ] ],
5162                                         $html
5163                                 );
5164                         }
5165                 }
5166
5167                 if ( MWNamespace::hasSubpages( $this->mNamespace ) ) {
5168                         // Optional notice for page itself and any parent page
5169                         $editnotice_base = $editnotice_ns;
5170                         foreach ( explode( '/', $this->mDbkeyform ) as $part ) {
5171                                 $editnotice_base .= '-' . $part;
5172                                 $msg = wfMessage( $editnotice_base );
5173                                 if ( $msg->exists() ) {
5174                                         $html = $msg->parseAsBlock();
5175                                         if ( trim( $html ) !== '' ) {
5176                                                 $notices[$editnotice_base] = Html::rawElement(
5177                                                         'div',
5178                                                         [ 'class' => [
5179                                                                 'mw-editnotice',
5180                                                                 'mw-editnotice-base',
5181                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
5182                                                         ] ],
5183                                                         $html
5184                                                 );
5185                                         }
5186                                 }
5187                         }
5188                 } else {
5189                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
5190                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->mDbkeyform, '/', '-' );
5191                         $msg = wfMessage( $editnoticeText );
5192                         if ( $msg->exists() ) {
5193                                 $html = $msg->parseAsBlock();
5194                                 if ( trim( $html ) !== '' ) {
5195                                         $notices[$editnoticeText] = Html::rawElement(
5196                                                 'div',
5197                                                 [ 'class' => [
5198                                                         'mw-editnotice',
5199                                                         'mw-editnotice-page',
5200                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
5201                                                 ] ],
5202                                                 $html
5203                                         );
5204                                 }
5205                         }
5206                 }
5207
5208                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
5209                 return $notices;
5210         }
5211
5212         /**
5213          * @return array
5214          */
5215         public function __sleep() {
5216                 return [
5217                         'mNamespace',
5218                         'mDbkeyform',
5219                         'mFragment',
5220                         'mInterwiki',
5221                         'mLocalInterwiki',
5222                         'mUserCaseDBKey',
5223                         'mDefaultNamespace',
5224                 ];
5225         }
5226
5227         public function __wakeup() {
5228                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5229                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5230                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5231         }
5232
5233 }