includes/Revision.php

   1 <?php
   2 /**
   3  * Representation of a page version.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 use Wikimedia\Rdbms\IDatabase;
  24 use MediaWiki\Linker\LinkTarget;
  25 use MediaWiki\MediaWikiServices;
  26 use Wikimedia\Rdbms\ResultWrapper;
  27 use Wikimedia\Rdbms\FakeResultWrapper;
  28
  29 /**
  30  * @todo document
  31  */
  32 class Revision implements IDBAccessObject {
  33         /** @var int|null */
  34         protected $mId;
  35         /** @var int|null */
  36         protected $mPage;
  37         /** @var string */
  38         protected $mUserText;
  39         /** @var string */
  40         protected $mOrigUserText;
  41         /** @var int */
  42         protected $mUser;
  43         /** @var bool */
  44         protected $mMinorEdit;
  45         /** @var string */
  46         protected $mTimestamp;
  47         /** @var int */
  48         protected $mDeleted;
  49         /** @var int */
  50         protected $mSize;
  51         /** @var string */
  52         protected $mSha1;
  53         /** @var int */
  54         protected $mParentId;
  55         /** @var string */
  56         protected $mComment;
  57         /** @var string */
  58         protected $mText;
  59         /** @var int */
  60         protected $mTextId;
  61         /** @var int */
  62         protected $mUnpatrolled;
  63
  64         /** @var stdClass|null */
  65         protected $mTextRow;
  66
  67         /**  @var null|Title */
  68         protected $mTitle;
  69         /** @var bool */
  70         protected $mCurrent;
  71         /** @var string */
  72         protected $mContentModel;
  73         /** @var string */
  74         protected $mContentFormat;
  75
  76         /** @var Content|null|bool */
  77         protected $mContent;
  78         /** @var null|ContentHandler */
  79         protected $mContentHandler;
  80
  81         /** @var int */
  82         protected $mQueryFlags = 0;
  83         /** @var bool Used for cached values to reload user text and rev_deleted */
  84         protected $mRefreshMutableFields = false;
  85         /** @var string Wiki ID; false means the current wiki */
  86         protected $mWiki = false;
  87
  88         // Revision deletion constants
  89         const DELETED_TEXT = 1;
  90         const DELETED_COMMENT = 2;
  91         const DELETED_USER = 4;
  92         const DELETED_RESTRICTED = 8;
  93         const SUPPRESSED_USER = 12; // convenience
  94         const SUPPRESSED_ALL = 15; // convenience
  95
  96         // Audience options for accessors
  97         const FOR_PUBLIC = 1;
  98         const FOR_THIS_USER = 2;
  99         const RAW = 3;
 100
 101         const TEXT_CACHE_GROUP = 'revisiontext:10'; // process cache name and max key count
 102
 103         /**
 104          * Load a page revision from a given revision ID number.
 105          * Returns null if no such revision can be found.
 106          *
 107          * $flags include:
 108          *      Revision::READ_LATEST  : Select the data from the master
 109          *      Revision::READ_LOCKING : Select & lock the data from the master
 110          *
 111          * @param int $id
 112          * @param int $flags (optional)
 113          * @return Revision|null
 114          */
 115         public static function newFromId( $id, $flags = 0 ) {
 116                 return self::newFromConds( [ 'rev_id' => intval( $id ) ], $flags );
 117         }
 118
 119         /**
 120          * Load either the current, or a specified, revision
 121          * that's attached to a given link target. If not attached
 122          * to that link target, will return null.
 123          *
 124          * $flags include:
 125          *      Revision::READ_LATEST  : Select the data from the master
 126          *      Revision::READ_LOCKING : Select & lock the data from the master
 127          *
 128          * @param LinkTarget $linkTarget
 129          * @param int $id (optional)
 130          * @param int $flags Bitfield (optional)
 131          * @return Revision|null
 132          */
 133         public static function newFromTitle( LinkTarget $linkTarget, $id = 0, $flags = 0 ) {
 134                 $conds = [
 135                         'page_namespace' => $linkTarget->getNamespace(),
 136                         'page_title' => $linkTarget->getDBkey()
 137                 ];
 138                 if ( $id ) {
 139                         // Use the specified ID
 140                         $conds['rev_id'] = $id;
 141                         return self::newFromConds( $conds, $flags );
 142                 } else {
 143                         // Use a join to get the latest revision
 144                         $conds[] = 'rev_id=page_latest';
 145                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 146                         return self::loadFromConds( $db, $conds, $flags );
 147                 }
 148         }
 149
 150         /**
 151          * Load either the current, or a specified, revision
 152          * that's attached to a given page ID.
 153          * Returns null if no such revision can be found.
 154          *
 155          * $flags include:
 156          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 157          *      Revision::READ_LOCKING : Select & lock the data from the master
 158          *
 159          * @param int $pageId
 160          * @param int $revId (optional)
 161          * @param int $flags Bitfield (optional)
 162          * @return Revision|null
 163          */
 164         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 165                 $conds = [ 'page_id' => $pageId ];
 166                 if ( $revId ) {
 167                         $conds['rev_id'] = $revId;
 168                         return self::newFromConds( $conds, $flags );
 169                 } else {
 170                         // Use a join to get the latest revision
 171                         $conds[] = 'rev_id = page_latest';
 172                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 173                         return self::loadFromConds( $db, $conds, $flags );
 174                 }
 175         }
 176
 177         /**
 178          * Make a fake revision object from an archive table row. This is queried
 179          * for permissions or even inserted (as in Special:Undelete)
 180          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 181          *
 182          * @param object $row
 183          * @param array $overrides
 184          *
 185          * @throws MWException
 186          * @return Revision
 187          */
 188         public static function newFromArchiveRow( $row, $overrides = [] ) {
 189                 global $wgContentHandlerUseDB;
 190
 191                 $attribs = $overrides + [
 192                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 193                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 194                         'comment'    => $row->ar_comment,
 195                         'user'       => $row->ar_user,
 196                         'user_text'  => $row->ar_user_text,
 197                         'timestamp'  => $row->ar_timestamp,
 198                         'minor_edit' => $row->ar_minor_edit,
 199                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 200                         'deleted'    => $row->ar_deleted,
 201                         'len'        => $row->ar_len,
 202                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 203                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 204                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 205                 ];
 206
 207                 if ( !$wgContentHandlerUseDB ) {
 208                         unset( $attribs['content_model'] );
 209                         unset( $attribs['content_format'] );
 210                 }
 211
 212                 if ( !isset( $attribs['title'] )
 213                         && isset( $row->ar_namespace )
 214                         && isset( $row->ar_title )
 215                 ) {
 216                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 217                 }
 218
 219                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 220                         // Pre-1.5 ar_text row
 221                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 222                         if ( $attribs['text'] === false ) {
 223                                 throw new MWException( 'Unable to load text from archive row (possibly T24624)' );
 224                         }
 225                 }
 226                 return new self( $attribs );
 227         }
 228
 229         /**
 230          * @since 1.19
 231          *
 232          * @param object $row
 233          * @return Revision
 234          */
 235         public static function newFromRow( $row ) {
 236                 return new self( $row );
 237         }
 238
 239         /**
 240          * Load a page revision from a given revision ID number.
 241          * Returns null if no such revision can be found.
 242          *
 243          * @param IDatabase $db
 244          * @param int $id
 245          * @return Revision|null
 246          */
 247         public static function loadFromId( $db, $id ) {
 248                 return self::loadFromConds( $db, [ 'rev_id' => intval( $id ) ] );
 249         }
 250
 251         /**
 252          * Load either the current, or a specified, revision
 253          * that's attached to a given page. If not attached
 254          * to that page, will return null.
 255          *
 256          * @param IDatabase $db
 257          * @param int $pageid
 258          * @param int $id
 259          * @return Revision|null
 260          */
 261         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 262                 $conds = [ 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) ];
 263                 if ( $id ) {
 264                         $conds['rev_id'] = intval( $id );
 265                 } else {
 266                         $conds[] = 'rev_id=page_latest';
 267                 }
 268                 return self::loadFromConds( $db, $conds );
 269         }
 270
 271         /**
 272          * Load either the current, or a specified, revision
 273          * that's attached to a given page. If not attached
 274          * to that page, will return null.
 275          *
 276          * @param IDatabase $db
 277          * @param Title $title
 278          * @param int $id
 279          * @return Revision|null
 280          */
 281         public static function loadFromTitle( $db, $title, $id = 0 ) {
 282                 if ( $id ) {
 283                         $matchId = intval( $id );
 284                 } else {
 285                         $matchId = 'page_latest';
 286                 }
 287                 return self::loadFromConds( $db,
 288                         [
 289                                 "rev_id=$matchId",
 290                                 'page_namespace' => $title->getNamespace(),
 291                                 'page_title' => $title->getDBkey()
 292                         ]
 293                 );
 294         }
 295
 296         /**
 297          * Load the revision for the given title with the given timestamp.
 298          * WARNING: Timestamps may in some circumstances not be unique,
 299          * so this isn't the best key to use.
 300          *
 301          * @param IDatabase $db
 302          * @param Title $title
 303          * @param string $timestamp
 304          * @return Revision|null
 305          */
 306         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 307                 return self::loadFromConds( $db,
 308                         [
 309                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 310                                 'page_namespace' => $title->getNamespace(),
 311                                 'page_title' => $title->getDBkey()
 312                         ]
 313                 );
 314         }
 315
 316         /**
 317          * Given a set of conditions, fetch a revision
 318          *
 319          * This method is used then a revision ID is qualified and
 320          * will incorporate some basic replica DB/master fallback logic
 321          *
 322          * @param array $conditions
 323          * @param int $flags (optional)
 324          * @return Revision|null
 325          */
 326         private static function newFromConds( $conditions, $flags = 0 ) {
 327                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 328
 329                 $rev = self::loadFromConds( $db, $conditions, $flags );
 330                 // Make sure new pending/committed revision are visibile later on
 331                 // within web requests to certain avoid bugs like T93866 and T94407.
 332                 if ( !$rev
 333                         && !( $flags & self::READ_LATEST )
 334                         && wfGetLB()->getServerCount() > 1
 335                         && wfGetLB()->hasOrMadeRecentMasterChanges()
 336                 ) {
 337                         $flags = self::READ_LATEST;
 338                         $db = wfGetDB( DB_MASTER );
 339                         $rev = self::loadFromConds( $db, $conditions, $flags );
 340                 }
 341
 342                 if ( $rev ) {
 343                         $rev->mQueryFlags = $flags;
 344                 }
 345
 346                 return $rev;
 347         }
 348
 349         /**
 350          * Given a set of conditions, fetch a revision from
 351          * the given database connection.
 352          *
 353          * @param IDatabase $db
 354          * @param array $conditions
 355          * @param int $flags (optional)
 356          * @return Revision|null
 357          */
 358         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 359                 $row = self::fetchFromConds( $db, $conditions, $flags );
 360                 if ( $row ) {
 361                         $rev = new Revision( $row );
 362                         $rev->mWiki = $db->getWikiID();
 363
 364                         return $rev;
 365                 }
 366
 367                 return null;
 368         }
 369
 370         /**
 371          * Return a wrapper for a series of database rows to
 372          * fetch all of a given page's revisions in turn.
 373          * Each row can be fed to the constructor to get objects.
 374          *
 375          * @param LinkTarget $title
 376          * @return ResultWrapper
 377          * @deprecated Since 1.28
 378          */
 379         public static function fetchRevision( LinkTarget $title ) {
 380                 $row = self::fetchFromConds(
 381                         wfGetDB( DB_REPLICA ),
 382                         [
 383                                 'rev_id=page_latest',
 384                                 'page_namespace' => $title->getNamespace(),
 385                                 'page_title' => $title->getDBkey()
 386                         ]
 387                 );
 388
 389                 return new FakeResultWrapper( $row ? [ $row ] : [] );
 390         }
 391
 392         /**
 393          * Given a set of conditions, return a ResultWrapper
 394          * which will return matching database rows with the
 395          * fields necessary to build Revision objects.
 396          *
 397          * @param IDatabase $db
 398          * @param array $conditions
 399          * @param int $flags (optional)
 400          * @return stdClass
 401          */
 402         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 403                 $fields = array_merge(
 404                         self::selectFields(),
 405                         self::selectPageFields(),
 406                         self::selectUserFields()
 407                 );
 408                 $options = [];
 409                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 410                         $options[] = 'FOR UPDATE';
 411                 }
 412                 return $db->selectRow(
 413                         [ 'revision', 'page', 'user' ],
 414                         $fields,
 415                         $conditions,
 416                         __METHOD__,
 417                         $options,
 418                         [ 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() ]
 419                 );
 420         }
 421
 422         /**
 423          * Return the value of a select() JOIN conds array for the user table.
 424          * This will get user table rows for logged-in users.
 425          * @since 1.19
 426          * @return array
 427          */
 428         public static function userJoinCond() {
 429                 return [ 'LEFT JOIN', [ 'rev_user != 0', 'user_id = rev_user' ] ];
 430         }
 431
 432         /**
 433          * Return the value of a select() page conds array for the page table.
 434          * This will assure that the revision(s) are not orphaned from live pages.
 435          * @since 1.19
 436          * @return array
 437          */
 438         public static function pageJoinCond() {
 439                 return [ 'INNER JOIN', [ 'page_id = rev_page' ] ];
 440         }
 441
 442         /**
 443          * Return the list of revision fields that should be selected to create
 444          * a new revision.
 445          * @return array
 446          */
 447         public static function selectFields() {
 448                 global $wgContentHandlerUseDB;
 449
 450                 $fields = [
 451                         'rev_id',
 452                         'rev_page',
 453                         'rev_text_id',
 454                         'rev_timestamp',
 455                         'rev_comment',
 456                         'rev_user_text',
 457                         'rev_user',
 458                         'rev_minor_edit',
 459                         'rev_deleted',
 460                         'rev_len',
 461                         'rev_parent_id',
 462                         'rev_sha1',
 463                 ];
 464
 465                 if ( $wgContentHandlerUseDB ) {
 466                         $fields[] = 'rev_content_format';
 467                         $fields[] = 'rev_content_model';
 468                 }
 469
 470                 return $fields;
 471         }
 472
 473         /**
 474          * Return the list of revision fields that should be selected to create
 475          * a new revision from an archive row.
 476          * @return array
 477          */
 478         public static function selectArchiveFields() {
 479                 global $wgContentHandlerUseDB;
 480                 $fields = [
 481                         'ar_id',
 482                         'ar_page_id',
 483                         'ar_rev_id',
 484                         'ar_text',
 485                         'ar_text_id',
 486                         'ar_timestamp',
 487                         'ar_comment',
 488                         'ar_user_text',
 489                         'ar_user',
 490                         'ar_minor_edit',
 491                         'ar_deleted',
 492                         'ar_len',
 493                         'ar_parent_id',
 494                         'ar_sha1',
 495                 ];
 496
 497                 if ( $wgContentHandlerUseDB ) {
 498                         $fields[] = 'ar_content_format';
 499                         $fields[] = 'ar_content_model';
 500                 }
 501                 return $fields;
 502         }
 503
 504         /**
 505          * Return the list of text fields that should be selected to read the
 506          * revision text
 507          * @return array
 508          */
 509         public static function selectTextFields() {
 510                 return [
 511                         'old_text',
 512                         'old_flags'
 513                 ];
 514         }
 515
 516         /**
 517          * Return the list of page fields that should be selected from page table
 518          * @return array
 519          */
 520         public static function selectPageFields() {
 521                 return [
 522                         'page_namespace',
 523                         'page_title',
 524                         'page_id',
 525                         'page_latest',
 526                         'page_is_redirect',
 527                         'page_len',
 528                 ];
 529         }
 530
 531         /**
 532          * Return the list of user fields that should be selected from user table
 533          * @return array
 534          */
 535         public static function selectUserFields() {
 536                 return [ 'user_name' ];
 537         }
 538
 539         /**
 540          * Do a batched query to get the parent revision lengths
 541          * @param IDatabase $db
 542          * @param array $revIds
 543          * @return array
 544          */
 545         public static function getParentLengths( $db, array $revIds ) {
 546                 $revLens = [];
 547                 if ( !$revIds ) {
 548                         return $revLens; // empty
 549                 }
 550                 $res = $db->select( 'revision',
 551                         [ 'rev_id', 'rev_len' ],
 552                         [ 'rev_id' => $revIds ],
 553                         __METHOD__ );
 554                 foreach ( $res as $row ) {
 555                         $revLens[$row->rev_id] = $row->rev_len;
 556                 }
 557                 return $revLens;
 558         }
 559
 560         /**
 561          * Constructor
 562          *
 563          * @param object|array $row Either a database row or an array
 564          * @throws MWException
 565          * @access private
 566          */
 567         function __construct( $row ) {
 568                 if ( is_object( $row ) ) {
 569                         $this->mId = intval( $row->rev_id );
 570                         $this->mPage = intval( $row->rev_page );
 571                         $this->mTextId = intval( $row->rev_text_id );
 572                         $this->mComment = $row->rev_comment;
 573                         $this->mUser = intval( $row->rev_user );
 574                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 575                         $this->mTimestamp = $row->rev_timestamp;
 576                         $this->mDeleted = intval( $row->rev_deleted );
 577
 578                         if ( !isset( $row->rev_parent_id ) ) {
 579                                 $this->mParentId = null;
 580                         } else {
 581                                 $this->mParentId = intval( $row->rev_parent_id );
 582                         }
 583
 584                         if ( !isset( $row->rev_len ) ) {
 585                                 $this->mSize = null;
 586                         } else {
 587                                 $this->mSize = intval( $row->rev_len );
 588                         }
 589
 590                         if ( !isset( $row->rev_sha1 ) ) {
 591                                 $this->mSha1 = null;
 592                         } else {
 593                                 $this->mSha1 = $row->rev_sha1;
 594                         }
 595
 596                         if ( isset( $row->page_latest ) ) {
 597                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 598                                 $this->mTitle = Title::newFromRow( $row );
 599                         } else {
 600                                 $this->mCurrent = false;
 601                                 $this->mTitle = null;
 602                         }
 603
 604                         if ( !isset( $row->rev_content_model ) ) {
 605                                 $this->mContentModel = null; # determine on demand if needed
 606                         } else {
 607                                 $this->mContentModel = strval( $row->rev_content_model );
 608                         }
 609
 610                         if ( !isset( $row->rev_content_format ) ) {
 611                                 $this->mContentFormat = null; # determine on demand if needed
 612                         } else {
 613                                 $this->mContentFormat = strval( $row->rev_content_format );
 614                         }
 615
 616                         // Lazy extraction...
 617                         $this->mText = null;
 618                         if ( isset( $row->old_text ) ) {
 619                                 $this->mTextRow = $row;
 620                         } else {
 621                                 // 'text' table row entry will be lazy-loaded
 622                                 $this->mTextRow = null;
 623                         }
 624
 625                         // Use user_name for users and rev_user_text for IPs...
 626                         $this->mUserText = null; // lazy load if left null
 627                         if ( $this->mUser == 0 ) {
 628                                 $this->mUserText = $row->rev_user_text; // IP user
 629                         } elseif ( isset( $row->user_name ) ) {
 630                                 $this->mUserText = $row->user_name; // logged-in user
 631                         }
 632                         $this->mOrigUserText = $row->rev_user_text;
 633                 } elseif ( is_array( $row ) ) {
 634                         // Build a new revision to be saved...
 635                         global $wgUser; // ugh
 636
 637                         # if we have a content object, use it to set the model and type
 638                         if ( !empty( $row['content'] ) ) {
 639                                 // @todo when is that set? test with external store setup! check out insertOn() [dk]
 640                                 if ( !empty( $row['text_id'] ) ) {
 641                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 642                                                 "can't serialize content object" );
 643                                 }
 644
 645                                 $row['content_model'] = $row['content']->getModel();
 646                                 # note: mContentFormat is initializes later accordingly
 647                                 # note: content is serialized later in this method!
 648                                 # also set text to null?
 649                         }
 650
 651                         $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 652                         $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 653                         $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 654                         $this->mUserText = isset( $row['user_text'] )
 655                                 ? strval( $row['user_text'] ) : $wgUser->getName();
 656                         $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 657                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 658                         $this->mTimestamp = isset( $row['timestamp'] )
 659                                 ? strval( $row['timestamp'] ) : wfTimestampNow();
 660                         $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 661                         $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 662                         $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 663                         $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 664
 665                         $this->mContentModel = isset( $row['content_model'] )
 666                                 ? strval( $row['content_model'] ) : null;
 667                         $this->mContentFormat = isset( $row['content_format'] )
 668                                 ? strval( $row['content_format'] ) : null;
 669
 670                         // Enforce spacing trimming on supplied text
 671                         $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 672                         $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 673                         $this->mTextRow = null;
 674
 675                         $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 676
 677                         // if we have a Content object, override mText and mContentModel
 678                         if ( !empty( $row['content'] ) ) {
 679                                 if ( !( $row['content'] instanceof Content ) ) {
 680                                         throw new MWException( '`content` field must contain a Content object.' );
 681                                 }
 682
 683                                 $handler = $this->getContentHandler();
 684                                 $this->mContent = $row['content'];
 685
 686                                 $this->mContentModel = $this->mContent->getModel();
 687                                 $this->mContentHandler = null;
 688
 689                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 690                         } elseif ( $this->mText !== null ) {
 691                                 $handler = $this->getContentHandler();
 692                                 $this->mContent = $handler->unserializeContent( $this->mText );
 693                         }
 694
 695                         // If we have a Title object, make sure it is consistent with mPage.
 696                         if ( $this->mTitle && $this->mTitle->exists() ) {
 697                                 if ( $this->mPage === null ) {
 698                                         // if the page ID wasn't known, set it now
 699                                         $this->mPage = $this->mTitle->getArticleID();
 700                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 701                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 702                                         // but it seems worth mentioning it in the log.
 703                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 704                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 705                                 }
 706                         }
 707
 708                         $this->mCurrent = false;
 709
 710                         // If we still have no length, see it we have the text to figure it out
 711                         if ( !$this->mSize && $this->mContent !== null ) {
 712                                 $this->mSize = $this->mContent->getSize();
 713                         }
 714
 715                         // Same for sha1
 716                         if ( $this->mSha1 === null ) {
 717                                 $this->mSha1 = $this->mText === null ? null : self::base36Sha1( $this->mText );
 718                         }
 719
 720                         // force lazy init
 721                         $this->getContentModel();
 722                         $this->getContentFormat();
 723                 } else {
 724                         throw new MWException( 'Revision constructor passed invalid row format.' );
 725                 }
 726                 $this->mUnpatrolled = null;
 727         }
 728
 729         /**
 730          * Get revision ID
 731          *
 732          * @return int|null
 733          */
 734         public function getId() {
 735                 return $this->mId;
 736         }
 737
 738         /**
 739          * Set the revision ID
 740          *
 741          * This should only be used for proposed revisions that turn out to be null edits
 742          *
 743          * @since 1.19
 744          * @param int $id
 745          */
 746         public function setId( $id ) {
 747                 $this->mId = (int)$id;
 748         }
 749
 750         /**
 751          * Set the user ID/name
 752          *
 753          * This should only be used for proposed revisions that turn out to be null edits
 754          *
 755          * @since 1.28
 756          * @param integer $id User ID
 757          * @param string $name User name
 758          */
 759         public function setUserIdAndName( $id, $name ) {
 760                 $this->mUser = (int)$id;
 761                 $this->mUserText = $name;
 762                 $this->mOrigUserText = $name;
 763         }
 764
 765         /**
 766          * Get text row ID
 767          *
 768          * @return int|null
 769          */
 770         public function getTextId() {
 771                 return $this->mTextId;
 772         }
 773
 774         /**
 775          * Get parent revision ID (the original previous page revision)
 776          *
 777          * @return int|null
 778          */
 779         public function getParentId() {
 780                 return $this->mParentId;
 781         }
 782
 783         /**
 784          * Returns the length of the text in this revision, or null if unknown.
 785          *
 786          * @return int|null
 787          */
 788         public function getSize() {
 789                 return $this->mSize;
 790         }
 791
 792         /**
 793          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 794          *
 795          * @return string|null
 796          */
 797         public function getSha1() {
 798                 return $this->mSha1;
 799         }
 800
 801         /**
 802          * Returns the title of the page associated with this entry or null.
 803          *
 804          * Will do a query, when title is not set and id is given.
 805          *
 806          * @return Title|null
 807          */
 808         public function getTitle() {
 809                 if ( $this->mTitle !== null ) {
 810                         return $this->mTitle;
 811                 }
 812                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 813                 if ( $this->mId !== null ) {
 814                         $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
 815                         $row = $dbr->selectRow(
 816                                 [ 'page', 'revision' ],
 817                                 self::selectPageFields(),
 818                                 [ 'page_id=rev_page', 'rev_id' => $this->mId ],
 819                                 __METHOD__
 820                         );
 821                         if ( $row ) {
 822                                 // @TODO: better foreign title handling
 823                                 $this->mTitle = Title::newFromRow( $row );
 824                         }
 825                 }
 826
 827                 if ( $this->mWiki === false || $this->mWiki === wfWikiID() ) {
 828                         // Loading by ID is best, though not possible for foreign titles
 829                         if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 830                                 $this->mTitle = Title::newFromID( $this->mPage );
 831                         }
 832                 }
 833
 834                 return $this->mTitle;
 835         }
 836
 837         /**
 838          * Set the title of the revision
 839          *
 840          * @param Title $title
 841          */
 842         public function setTitle( $title ) {
 843                 $this->mTitle = $title;
 844         }
 845
 846         /**
 847          * Get the page ID
 848          *
 849          * @return int|null
 850          */
 851         public function getPage() {
 852                 return $this->mPage;
 853         }
 854
 855         /**
 856          * Fetch revision's user id if it's available to the specified audience.
 857          * If the specified audience does not have access to it, zero will be
 858          * returned.
 859          *
 860          * @param int $audience One of:
 861          *   Revision::FOR_PUBLIC       to be displayed to all users
 862          *   Revision::FOR_THIS_USER    to be displayed to the given user
 863          *   Revision::RAW              get the ID regardless of permissions
 864          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 865          *   to the $audience parameter
 866          * @return int
 867          */
 868         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 869                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 870                         return 0;
 871                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 872                         return 0;
 873                 } else {
 874                         return $this->mUser;
 875                 }
 876         }
 877
 878         /**
 879          * Fetch revision's user id without regard for the current user's permissions
 880          *
 881          * @return int
 882          * @deprecated since 1.25, use getUser( Revision::RAW )
 883          */
 884         public function getRawUser() {
 885                 wfDeprecated( __METHOD__, '1.25' );
 886                 return $this->getUser( self::RAW );
 887         }
 888
 889         /**
 890          * Fetch revision's username if it's available to the specified audience.
 891          * If the specified audience does not have access to the username, an
 892          * empty string will be returned.
 893          *
 894          * @param int $audience One of:
 895          *   Revision::FOR_PUBLIC       to be displayed to all users
 896          *   Revision::FOR_THIS_USER    to be displayed to the given user
 897          *   Revision::RAW              get the text regardless of permissions
 898          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 899          *   to the $audience parameter
 900          * @return string
 901          */
 902         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 903                 $this->loadMutableFields();
 904
 905                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 906                         return '';
 907                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 908                         return '';
 909                 } else {
 910                         if ( $this->mUserText === null ) {
 911                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 912                                 if ( $this->mUserText === false ) {
 913                                         # This shouldn't happen, but it can if the wiki was recovered
 914                                         # via importing revs and there is no user table entry yet.
 915                                         $this->mUserText = $this->mOrigUserText;
 916                                 }
 917                         }
 918                         return $this->mUserText;
 919                 }
 920         }
 921
 922         /**
 923          * Fetch revision's username without regard for view restrictions
 924          *
 925          * @return string
 926          * @deprecated since 1.25, use getUserText( Revision::RAW )
 927          */
 928         public function getRawUserText() {
 929                 wfDeprecated( __METHOD__, '1.25' );
 930                 return $this->getUserText( self::RAW );
 931         }
 932
 933         /**
 934          * Fetch revision comment if it's available to the specified audience.
 935          * If the specified audience does not have access to the comment, an
 936          * empty string will be returned.
 937          *
 938          * @param int $audience One of:
 939          *   Revision::FOR_PUBLIC       to be displayed to all users
 940          *   Revision::FOR_THIS_USER    to be displayed to the given user
 941          *   Revision::RAW              get the text regardless of permissions
 942          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 943          *   to the $audience parameter
 944          * @return string
 945          */
 946         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 947                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 948                         return '';
 949                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 950                         return '';
 951                 } else {
 952                         return $this->mComment;
 953                 }
 954         }
 955
 956         /**
 957          * Fetch revision comment without regard for the current user's permissions
 958          *
 959          * @return string
 960          * @deprecated since 1.25, use getComment( Revision::RAW )
 961          */
 962         public function getRawComment() {
 963                 wfDeprecated( __METHOD__, '1.25' );
 964                 return $this->getComment( self::RAW );
 965         }
 966
 967         /**
 968          * @return bool
 969          */
 970         public function isMinor() {
 971                 return (bool)$this->mMinorEdit;
 972         }
 973
 974         /**
 975          * @return int Rcid of the unpatrolled row, zero if there isn't one
 976          */
 977         public function isUnpatrolled() {
 978                 if ( $this->mUnpatrolled !== null ) {
 979                         return $this->mUnpatrolled;
 980                 }
 981                 $rc = $this->getRecentChange();
 982                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 983                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 984                 } else {
 985                         $this->mUnpatrolled = 0;
 986                 }
 987                 return $this->mUnpatrolled;
 988         }
 989
 990         /**
 991          * Get the RC object belonging to the current revision, if there's one
 992          *
 993          * @param int $flags (optional) $flags include:
 994          *      Revision::READ_LATEST  : Select the data from the master
 995          *
 996          * @since 1.22
 997          * @return RecentChange|null
 998          */
 999         public function getRecentChange( $flags = 0 ) {
1000                 $dbr = wfGetDB( DB_REPLICA );
1001
1002                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
1003
1004                 return RecentChange::newFromConds(
1005                         [
1006                                 'rc_user_text' => $this->getUserText( Revision::RAW ),
1007                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
1008                                 'rc_this_oldid' => $this->getId()
1009                         ],
1010                         __METHOD__,
1011                         $dbType
1012                 );
1013         }
1014
1015         /**
1016          * @param int $field One of DELETED_* bitfield constants
1017          *
1018          * @return bool
1019          */
1020         public function isDeleted( $field ) {
1021                 if ( $this->isCurrent() && $field === self::DELETED_TEXT ) {
1022                         // Current revisions of pages cannot have the content hidden. Skipping this
1023                         // check is very useful for Parser as it fetches templates using newKnownCurrent().
1024                         // Calling getVisibility() in that case triggers a verification database query.
1025                         return false; // no need to check
1026                 }
1027
1028                 return ( $this->getVisibility() & $field ) == $field;
1029         }
1030
1031         /**
1032          * Get the deletion bitfield of the revision
1033          *
1034          * @return int
1035          */
1036         public function getVisibility() {
1037                 $this->loadMutableFields();
1038
1039                 return (int)$this->mDeleted;
1040         }
1041
1042         /**
1043          * Fetch revision content if it's available to the specified audience.
1044          * If the specified audience does not have the ability to view this
1045          * revision, null will be returned.
1046          *
1047          * @param int $audience One of:
1048          *   Revision::FOR_PUBLIC       to be displayed to all users
1049          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1050          *   Revision::RAW              get the text regardless of permissions
1051          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1052          *   to the $audience parameter
1053          * @since 1.21
1054          * @return Content|null
1055          */
1056         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1057                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1058                         return null;
1059                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1060                         return null;
1061                 } else {
1062                         return $this->getContentInternal();
1063                 }
1064         }
1065
1066         /**
1067          * Get original serialized data (without checking view restrictions)
1068          *
1069          * @since 1.21
1070          * @return string
1071          */
1072         public function getSerializedData() {
1073                 if ( $this->mText === null ) {
1074                         // Revision is immutable. Load on demand.
1075                         $this->mText = $this->loadText();
1076                 }
1077
1078                 return $this->mText;
1079         }
1080
1081         /**
1082          * Gets the content object for the revision (or null on failure).
1083          *
1084          * Note that for mutable Content objects, each call to this method will return a
1085          * fresh clone.
1086          *
1087          * @since 1.21
1088          * @return Content|null The Revision's content, or null on failure.
1089          */
1090         protected function getContentInternal() {
1091                 if ( $this->mContent === null ) {
1092                         $text = $this->getSerializedData();
1093
1094                         if ( $text !== null && $text !== false ) {
1095                                 // Unserialize content
1096                                 $handler = $this->getContentHandler();
1097                                 $format = $this->getContentFormat();
1098
1099                                 $this->mContent = $handler->unserializeContent( $text, $format );
1100                         }
1101                 }
1102
1103                 // NOTE: copy() will return $this for immutable content objects
1104                 return $this->mContent ? $this->mContent->copy() : null;
1105         }
1106
1107         /**
1108          * Returns the content model for this revision.
1109          *
1110          * If no content model was stored in the database, the default content model for the title is
1111          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1112          * is used as a last resort.
1113          *
1114          * @return string The content model id associated with this revision,
1115          *     see the CONTENT_MODEL_XXX constants.
1116          */
1117         public function getContentModel() {
1118                 if ( !$this->mContentModel ) {
1119                         $title = $this->getTitle();
1120                         if ( $title ) {
1121                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1122                         } else {
1123                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1124                         }
1125
1126                         assert( !empty( $this->mContentModel ) );
1127                 }
1128
1129                 return $this->mContentModel;
1130         }
1131
1132         /**
1133          * Returns the content format for this revision.
1134          *
1135          * If no content format was stored in the database, the default format for this
1136          * revision's content model is returned.
1137          *
1138          * @return string The content format id associated with this revision,
1139          *     see the CONTENT_FORMAT_XXX constants.
1140          */
1141         public function getContentFormat() {
1142                 if ( !$this->mContentFormat ) {
1143                         $handler = $this->getContentHandler();
1144                         $this->mContentFormat = $handler->getDefaultFormat();
1145
1146                         assert( !empty( $this->mContentFormat ) );
1147                 }
1148
1149                 return $this->mContentFormat;
1150         }
1151
1152         /**
1153          * Returns the content handler appropriate for this revision's content model.
1154          *
1155          * @throws MWException
1156          * @return ContentHandler
1157          */
1158         public function getContentHandler() {
1159                 if ( !$this->mContentHandler ) {
1160                         $model = $this->getContentModel();
1161                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1162
1163                         $format = $this->getContentFormat();
1164
1165                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1166                                 throw new MWException( "Oops, the content format $format is not supported for "
1167                                         . "this content model, $model" );
1168                         }
1169                 }
1170
1171                 return $this->mContentHandler;
1172         }
1173
1174         /**
1175          * @return string
1176          */
1177         public function getTimestamp() {
1178                 return wfTimestamp( TS_MW, $this->mTimestamp );
1179         }
1180
1181         /**
1182          * @return bool
1183          */
1184         public function isCurrent() {
1185                 return $this->mCurrent;
1186         }
1187
1188         /**
1189          * Get previous revision for this title
1190          *
1191          * @return Revision|null
1192          */
1193         public function getPrevious() {
1194                 if ( $this->getTitle() ) {
1195                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1196                         if ( $prev ) {
1197                                 return self::newFromTitle( $this->getTitle(), $prev );
1198                         }
1199                 }
1200                 return null;
1201         }
1202
1203         /**
1204          * Get next revision for this title
1205          *
1206          * @return Revision|null
1207          */
1208         public function getNext() {
1209                 if ( $this->getTitle() ) {
1210                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1211                         if ( $next ) {
1212                                 return self::newFromTitle( $this->getTitle(), $next );
1213                         }
1214                 }
1215                 return null;
1216         }
1217
1218         /**
1219          * Get previous revision Id for this page_id
1220          * This is used to populate rev_parent_id on save
1221          *
1222          * @param IDatabase $db
1223          * @return int
1224          */
1225         private function getPreviousRevisionId( $db ) {
1226                 if ( $this->mPage === null ) {
1227                         return 0;
1228                 }
1229                 # Use page_latest if ID is not given
1230                 if ( !$this->mId ) {
1231                         $prevId = $db->selectField( 'page', 'page_latest',
1232                                 [ 'page_id' => $this->mPage ],
1233                                 __METHOD__ );
1234                 } else {
1235                         $prevId = $db->selectField( 'revision', 'rev_id',
1236                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1237                                 __METHOD__,
1238                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1239                 }
1240                 return intval( $prevId );
1241         }
1242
1243         /**
1244          * Get revision text associated with an old or archive row
1245          *
1246          * Both the flags and the text field must be included. Including the old_id
1247          * field will activate cache usage as long as the $wiki parameter is not set.
1248          *
1249          * @param stdClass $row The text data
1250          * @param string $prefix Table prefix (default 'old_')
1251          * @param string|bool $wiki The name of the wiki to load the revision text from
1252          *   (same as the the wiki $row was loaded from) or false to indicate the local
1253          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1254          *   identifier as understood by the LoadBalancer class.
1255          * @return string|false Text the text requested or false on failure
1256          */
1257         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1258                 $textField = $prefix . 'text';
1259                 $flagsField = $prefix . 'flags';
1260
1261                 if ( isset( $row->$flagsField ) ) {
1262                         $flags = explode( ',', $row->$flagsField );
1263                 } else {
1264                         $flags = [];
1265                 }
1266
1267                 if ( isset( $row->$textField ) ) {
1268                         $text = $row->$textField;
1269                 } else {
1270                         return false;
1271                 }
1272
1273                 // Use external methods for external objects, text in table is URL-only then
1274                 if ( in_array( 'external', $flags ) ) {
1275                         $url = $text;
1276                         $parts = explode( '://', $url, 2 );
1277                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1278                                 return false;
1279                         }
1280
1281                         if ( isset( $row->old_id ) && $wiki === false ) {
1282                                 // Make use of the wiki-local revision text cache
1283                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1284                                 // The cached value should be decompressed, so handle that and return here
1285                                 return $cache->getWithSetCallback(
1286                                         $cache->makeKey( 'revisiontext', 'textid', $row->old_id ),
1287                                         self::getCacheTTL( $cache ),
1288                                         function () use ( $url, $wiki, $flags ) {
1289                                                 // No negative caching per Revision::loadText()
1290                                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1291
1292                                                 return self::decompressRevisionText( $text, $flags );
1293                                         },
1294                                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1295                                 );
1296                         } else {
1297                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1298                         }
1299                 }
1300
1301                 return self::decompressRevisionText( $text, $flags );
1302         }
1303
1304         /**
1305          * If $wgCompressRevisions is enabled, we will compress data.
1306          * The input string is modified in place.
1307          * Return value is the flags field: contains 'gzip' if the
1308          * data is compressed, and 'utf-8' if we're saving in UTF-8
1309          * mode.
1310          *
1311          * @param mixed $text Reference to a text
1312          * @return string
1313          */
1314         public static function compressRevisionText( &$text ) {
1315                 global $wgCompressRevisions;
1316                 $flags = [];
1317
1318                 # Revisions not marked this way will be converted
1319                 # on load if $wgLegacyCharset is set in the future.
1320                 $flags[] = 'utf-8';
1321
1322                 if ( $wgCompressRevisions ) {
1323                         if ( function_exists( 'gzdeflate' ) ) {
1324                                 $deflated = gzdeflate( $text );
1325
1326                                 if ( $deflated === false ) {
1327                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1328                                 } else {
1329                                         $text = $deflated;
1330                                         $flags[] = 'gzip';
1331                                 }
1332                         } else {
1333                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1334                         }
1335                 }
1336                 return implode( ',', $flags );
1337         }
1338
1339         /**
1340          * Re-converts revision text according to it's flags.
1341          *
1342          * @param mixed $text Reference to a text
1343          * @param array $flags Compression flags
1344          * @return string|bool Decompressed text, or false on failure
1345          */
1346         public static function decompressRevisionText( $text, $flags ) {
1347                 global $wgLegacyEncoding, $wgContLang;
1348
1349                 if ( $text === false ) {
1350                         // Text failed to be fetched; nothing to do
1351                         return false;
1352                 }
1353
1354                 if ( in_array( 'gzip', $flags ) ) {
1355                         # Deal with optional compression of archived pages.
1356                         # This can be done periodically via maintenance/compressOld.php, and
1357                         # as pages are saved if $wgCompressRevisions is set.
1358                         $text = gzinflate( $text );
1359
1360                         if ( $text === false ) {
1361                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1362                                 return false;
1363                         }
1364                 }
1365
1366                 if ( in_array( 'object', $flags ) ) {
1367                         # Generic compressed storage
1368                         $obj = unserialize( $text );
1369                         if ( !is_object( $obj ) ) {
1370                                 // Invalid object
1371                                 return false;
1372                         }
1373                         $text = $obj->getText();
1374                 }
1375
1376                 if ( $text !== false && $wgLegacyEncoding
1377                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1378                 ) {
1379                         # Old revisions kept around in a legacy encoding?
1380                         # Upconvert on demand.
1381                         # ("utf8" checked for compatibility with some broken
1382                         #  conversion scripts 2008-12-30)
1383                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1384                 }
1385
1386                 return $text;
1387         }
1388
1389         /**
1390          * Insert a new revision into the database, returning the new revision ID
1391          * number on success and dies horribly on failure.
1392          *
1393          * @param IDatabase $dbw (master connection)
1394          * @throws MWException
1395          * @return int
1396          */
1397         public function insertOn( $dbw ) {
1398                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1399
1400                 // We're inserting a new revision, so we have to use master anyway.
1401                 // If it's a null revision, it may have references to rows that
1402                 // are not in the replica yet (the text row).
1403                 $this->mQueryFlags |= self::READ_LATEST;
1404
1405                 // Not allowed to have rev_page equal to 0, false, etc.
1406                 if ( !$this->mPage ) {
1407                         $title = $this->getTitle();
1408                         if ( $title instanceof Title ) {
1409                                 $titleText = ' for page ' . $title->getPrefixedText();
1410                         } else {
1411                                 $titleText = '';
1412                         }
1413                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1414                 }
1415
1416                 $this->checkContentModel();
1417
1418                 $data = $this->mText;
1419                 $flags = self::compressRevisionText( $data );
1420
1421                 # Write to external storage if required
1422                 if ( $wgDefaultExternalStore ) {
1423                         // Store and get the URL
1424                         $data = ExternalStore::insertToDefault( $data );
1425                         if ( !$data ) {
1426                                 throw new MWException( "Unable to store text to external storage" );
1427                         }
1428                         if ( $flags ) {
1429                                 $flags .= ',';
1430                         }
1431                         $flags .= 'external';
1432                 }
1433
1434                 # Record the text (or external storage URL) to the text table
1435                 if ( $this->mTextId === null ) {
1436                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1437                         $dbw->insert( 'text',
1438                                 [
1439                                         'old_id' => $old_id,
1440                                         'old_text' => $data,
1441                                         'old_flags' => $flags,
1442                                 ], __METHOD__
1443                         );
1444                         $this->mTextId = $dbw->insertId();
1445                 }
1446
1447                 if ( $this->mComment === null ) {
1448                         $this->mComment = "";
1449                 }
1450
1451                 # Record the edit in revisions
1452                 $rev_id = $this->mId !== null
1453                         ? $this->mId
1454                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1455                 $row = [
1456                         'rev_id'         => $rev_id,
1457                         'rev_page'       => $this->mPage,
1458                         'rev_text_id'    => $this->mTextId,
1459                         'rev_comment'    => $this->mComment,
1460                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1461                         'rev_user'       => $this->mUser,
1462                         'rev_user_text'  => $this->mUserText,
1463                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1464                         'rev_deleted'    => $this->mDeleted,
1465                         'rev_len'        => $this->mSize,
1466                         'rev_parent_id'  => $this->mParentId === null
1467                                 ? $this->getPreviousRevisionId( $dbw )
1468                                 : $this->mParentId,
1469                         'rev_sha1'       => $this->mSha1 === null
1470                                 ? Revision::base36Sha1( $this->mText )
1471                                 : $this->mSha1,
1472                 ];
1473
1474                 if ( $wgContentHandlerUseDB ) {
1475                         // NOTE: Store null for the default model and format, to save space.
1476                         // XXX: Makes the DB sensitive to changed defaults.
1477                         // Make this behavior optional? Only in miser mode?
1478
1479                         $model = $this->getContentModel();
1480                         $format = $this->getContentFormat();
1481
1482                         $title = $this->getTitle();
1483
1484                         if ( $title === null ) {
1485                                 throw new MWException( "Insufficient information to determine the title of the "
1486                                         . "revision's page!" );
1487                         }
1488
1489                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1490                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1491
1492                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1493                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1494                 }
1495
1496                 $dbw->insert( 'revision', $row, __METHOD__ );
1497
1498                 $this->mId = $rev_id !== null ? $rev_id : $dbw->insertId();
1499
1500                 // Assertion to try to catch T92046
1501                 if ( (int)$this->mId === 0 ) {
1502                         throw new UnexpectedValueException(
1503                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1504                                         var_export( $row, 1 )
1505                         );
1506                 }
1507
1508                 // Avoid PHP 7.1 warning of passing $this by reference
1509                 $revision = $this;
1510                 Hooks::run( 'RevisionInsertComplete', [ &$revision, $data, $flags ] );
1511
1512                 return $this->mId;
1513         }
1514
1515         protected function checkContentModel() {
1516                 global $wgContentHandlerUseDB;
1517
1518                 // Note: may return null for revisions that have not yet been inserted
1519                 $title = $this->getTitle();
1520
1521                 $model = $this->getContentModel();
1522                 $format = $this->getContentFormat();
1523                 $handler = $this->getContentHandler();
1524
1525                 if ( !$handler->isSupportedFormat( $format ) ) {
1526                         $t = $title->getPrefixedDBkey();
1527
1528                         throw new MWException( "Can't use format $format with content model $model on $t" );
1529                 }
1530
1531                 if ( !$wgContentHandlerUseDB && $title ) {
1532                         // if $wgContentHandlerUseDB is not set,
1533                         // all revisions must use the default content model and format.
1534
1535                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1536                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1537                         $defaultFormat = $defaultHandler->getDefaultFormat();
1538
1539                         if ( $this->getContentModel() != $defaultModel ) {
1540                                 $t = $title->getPrefixedDBkey();
1541
1542                                 throw new MWException( "Can't save non-default content model with "
1543                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1544                                         . "default for $t is $defaultModel" );
1545                         }
1546
1547                         if ( $this->getContentFormat() != $defaultFormat ) {
1548                                 $t = $title->getPrefixedDBkey();
1549
1550                                 throw new MWException( "Can't use non-default content format with "
1551                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1552                                         . "default for $t is $defaultFormat" );
1553                         }
1554                 }
1555
1556                 $content = $this->getContent( Revision::RAW );
1557                 $prefixedDBkey = $title->getPrefixedDBkey();
1558                 $revId = $this->mId;
1559
1560                 if ( !$content ) {
1561                         throw new MWException(
1562                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1563                         );
1564                 }
1565                 if ( !$content->isValid() ) {
1566                         throw new MWException(
1567                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1568                         );
1569                 }
1570         }
1571
1572         /**
1573          * Get the base 36 SHA-1 value for a string of text
1574          * @param string $text
1575          * @return string
1576          */
1577         public static function base36Sha1( $text ) {
1578                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1579         }
1580
1581         /**
1582          * Get the text cache TTL
1583          *
1584          * @param WANObjectCache $cache
1585          * @return integer
1586          */
1587         private static function getCacheTTL( WANObjectCache $cache ) {
1588                 global $wgRevisionCacheExpiry;
1589
1590                 if ( $cache->getQoS( $cache::ATTR_EMULATION ) <= $cache::QOS_EMULATION_SQL ) {
1591                         // Do not cache RDBMs blobs in...the RDBMs store
1592                         $ttl = $cache::TTL_UNCACHEABLE;
1593                 } else {
1594                         $ttl = $wgRevisionCacheExpiry ?: $cache::TTL_UNCACHEABLE;
1595                 }
1596
1597                 return $ttl;
1598         }
1599
1600         /**
1601          * Lazy-load the revision's text.
1602          * Currently hardcoded to the 'text' table storage engine.
1603          *
1604          * @return string|bool The revision's text, or false on failure
1605          */
1606         private function loadText() {
1607                 $cache = ObjectCache::getMainWANInstance();
1608
1609                 // No negative caching; negative hits on text rows may be due to corrupted replica DBs
1610                 return $cache->getWithSetCallback(
1611                         $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
1612                         self::getCacheTTL( $cache ),
1613                         function () {
1614                                 return $this->fetchText();
1615                         },
1616                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1617                 );
1618         }
1619
1620         private function fetchText() {
1621                 $textId = $this->getTextId();
1622
1623                 // If we kept data for lazy extraction, use it now...
1624                 if ( $this->mTextRow !== null ) {
1625                         $row = $this->mTextRow;
1626                         $this->mTextRow = null;
1627                 } else {
1628                         $row = null;
1629                 }
1630
1631                 // Callers doing updates will pass in READ_LATEST as usual. Since the text/blob tables
1632                 // do not normally get rows changed around, set READ_LATEST_IMMUTABLE in those cases.
1633                 $flags = $this->mQueryFlags;
1634                 $flags |= DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST )
1635                         ? self::READ_LATEST_IMMUTABLE
1636                         : 0;
1637
1638                 list( $index, $options, $fallbackIndex, $fallbackOptions ) =
1639                         DBAccessObjectUtils::getDBOptions( $flags );
1640
1641                 if ( !$row ) {
1642                         // Text data is immutable; check replica DBs first.
1643                         $row = wfGetDB( $index )->selectRow(
1644                                 'text',
1645                                 [ 'old_text', 'old_flags' ],
1646                                 [ 'old_id' => $textId ],
1647                                 __METHOD__,
1648                                 $options
1649                         );
1650                 }
1651
1652                 // Fallback to DB_MASTER in some cases if the row was not found
1653                 if ( !$row && $fallbackIndex !== null ) {
1654                         // Use FOR UPDATE if it was used to fetch this revision. This avoids missing the row
1655                         // due to REPEATABLE-READ. Also fallback to the master if READ_LATEST is provided.
1656                         $row = wfGetDB( $fallbackIndex )->selectRow(
1657                                 'text',
1658                                 [ 'old_text', 'old_flags' ],
1659                                 [ 'old_id' => $textId ],
1660                                 __METHOD__,
1661                                 $fallbackOptions
1662                         );
1663                 }
1664
1665                 if ( !$row ) {
1666                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1667                 }
1668
1669                 $text = self::getRevisionText( $row );
1670                 if ( $row && $text === false ) {
1671                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1672                 }
1673
1674                 return is_string( $text ) ? $text : false;
1675         }
1676
1677         /**
1678          * Create a new null-revision for insertion into a page's
1679          * history. This will not re-save the text, but simply refer
1680          * to the text from the previous version.
1681          *
1682          * Such revisions can for instance identify page rename
1683          * operations and other such meta-modifications.
1684          *
1685          * @param IDatabase $dbw
1686          * @param int $pageId ID number of the page to read from
1687          * @param string $summary Revision's summary
1688          * @param bool $minor Whether the revision should be considered as minor
1689          * @param User|null $user User object to use or null for $wgUser
1690          * @return Revision|null Revision or null on error
1691          */
1692         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1693                 global $wgContentHandlerUseDB, $wgContLang;
1694
1695                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1696                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1697
1698                 if ( $wgContentHandlerUseDB ) {
1699                         $fields[] = 'rev_content_model';
1700                         $fields[] = 'rev_content_format';
1701                 }
1702
1703                 $current = $dbw->selectRow(
1704                         [ 'page', 'revision' ],
1705                         $fields,
1706                         [
1707                                 'page_id' => $pageId,
1708                                 'page_latest=rev_id',
1709                         ],
1710                         __METHOD__,
1711                         [ 'FOR UPDATE' ] // T51581
1712                 );
1713
1714                 if ( $current ) {
1715                         if ( !$user ) {
1716                                 global $wgUser;
1717                                 $user = $wgUser;
1718                         }
1719
1720                         // Truncate for whole multibyte characters
1721                         $summary = $wgContLang->truncate( $summary, 255 );
1722
1723                         $row = [
1724                                 'page'       => $pageId,
1725                                 'user_text'  => $user->getName(),
1726                                 'user'       => $user->getId(),
1727                                 'comment'    => $summary,
1728                                 'minor_edit' => $minor,
1729                                 'text_id'    => $current->rev_text_id,
1730                                 'parent_id'  => $current->page_latest,
1731                                 'len'        => $current->rev_len,
1732                                 'sha1'       => $current->rev_sha1
1733                         ];
1734
1735                         if ( $wgContentHandlerUseDB ) {
1736                                 $row['content_model'] = $current->rev_content_model;
1737                                 $row['content_format'] = $current->rev_content_format;
1738                         }
1739
1740                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1741
1742                         $revision = new Revision( $row );
1743                 } else {
1744                         $revision = null;
1745                 }
1746
1747                 return $revision;
1748         }
1749
1750         /**
1751          * Determine if the current user is allowed to view a particular
1752          * field of this revision, if it's marked as deleted.
1753          *
1754          * @param int $field One of self::DELETED_TEXT,
1755          *                              self::DELETED_COMMENT,
1756          *                              self::DELETED_USER
1757          * @param User|null $user User object to check, or null to use $wgUser
1758          * @return bool
1759          */
1760         public function userCan( $field, User $user = null ) {
1761                 return self::userCanBitfield( $this->getVisibility(), $field, $user );
1762         }
1763
1764         /**
1765          * Determine if the current user is allowed to view a particular
1766          * field of this revision, if it's marked as deleted. This is used
1767          * by various classes to avoid duplication.
1768          *
1769          * @param int $bitfield Current field
1770          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1771          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1772          *                               self::DELETED_USER = File::DELETED_USER
1773          * @param User|null $user User object to check, or null to use $wgUser
1774          * @param Title|null $title A Title object to check for per-page restrictions on,
1775          *                          instead of just plain userrights
1776          * @return bool
1777          */
1778         public static function userCanBitfield( $bitfield, $field, User $user = null,
1779                 Title $title = null
1780         ) {
1781                 if ( $bitfield & $field ) { // aspect is deleted
1782                         if ( $user === null ) {
1783                                 global $wgUser;
1784                                 $user = $wgUser;
1785                         }
1786                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1787                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1788                         } elseif ( $field & self::DELETED_TEXT ) {
1789                                 $permissions = [ 'deletedtext' ];
1790                         } else {
1791                                 $permissions = [ 'deletedhistory' ];
1792                         }
1793                         $permissionlist = implode( ', ', $permissions );
1794                         if ( $title === null ) {
1795                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1796                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1797                         } else {
1798                                 $text = $title->getPrefixedText();
1799                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1800                                 foreach ( $permissions as $perm ) {
1801                                         if ( $title->userCan( $perm, $user ) ) {
1802                                                 return true;
1803                                         }
1804                                 }
1805                                 return false;
1806                         }
1807                 } else {
1808                         return true;
1809                 }
1810         }
1811
1812         /**
1813          * Get rev_timestamp from rev_id, without loading the rest of the row
1814          *
1815          * @param Title $title
1816          * @param int $id
1817          * @param int $flags
1818          * @return string|bool False if not found
1819          */
1820         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1821                 $db = ( $flags & self::READ_LATEST )
1822                         ? wfGetDB( DB_MASTER )
1823                         : wfGetDB( DB_REPLICA );
1824                 // Casting fix for databases that can't take '' for rev_id
1825                 if ( $id == '' ) {
1826                         $id = 0;
1827                 }
1828                 $conds = [ 'rev_id' => $id ];
1829                 $conds['rev_page'] = $title->getArticleID();
1830                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1831
1832                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
1833         }
1834
1835         /**
1836          * Get count of revisions per page...not very efficient
1837          *
1838          * @param IDatabase $db
1839          * @param int $id Page id
1840          * @return int
1841          */
1842         static function countByPageId( $db, $id ) {
1843                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
1844                         [ 'rev_page' => $id ], __METHOD__ );
1845                 if ( $row ) {
1846                         return $row->revCount;
1847                 }
1848                 return 0;
1849         }
1850
1851         /**
1852          * Get count of revisions per page...not very efficient
1853          *
1854          * @param IDatabase $db
1855          * @param Title $title
1856          * @return int
1857          */
1858         static function countByTitle( $db, $title ) {
1859                 $id = $title->getArticleID();
1860                 if ( $id ) {
1861                         return self::countByPageId( $db, $id );
1862                 }
1863                 return 0;
1864         }
1865
1866         /**
1867          * Check if no edits were made by other users since
1868          * the time a user started editing the page. Limit to
1869          * 50 revisions for the sake of performance.
1870          *
1871          * @since 1.20
1872          * @deprecated since 1.24
1873          *
1874          * @param IDatabase|int $db The Database to perform the check on. May be given as a
1875          *        Database object or a database identifier usable with wfGetDB.
1876          * @param int $pageId The ID of the page in question
1877          * @param int $userId The ID of the user in question
1878          * @param string $since Look at edits since this time
1879          *
1880          * @return bool True if the given user was the only one to edit since the given timestamp
1881          */
1882         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1883                 if ( !$userId ) {
1884                         return false;
1885                 }
1886
1887                 if ( is_int( $db ) ) {
1888                         $db = wfGetDB( $db );
1889                 }
1890
1891                 $res = $db->select( 'revision',
1892                         'rev_user',
1893                         [
1894                                 'rev_page' => $pageId,
1895                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1896                         ],
1897                         __METHOD__,
1898                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
1899                 foreach ( $res as $row ) {
1900                         if ( $row->rev_user != $userId ) {
1901                                 return false;
1902                         }
1903                 }
1904                 return true;
1905         }
1906
1907         /**
1908          * Load a revision based on a known page ID and current revision ID from the DB
1909          *
1910          * This method allows for the use of caching, though accessing anything that normally
1911          * requires permission checks (aside from the text) will trigger a small DB lookup.
1912          * The title will also be lazy loaded, though setTitle() can be used to preload it.
1913          *
1914          * @param IDatabase $db
1915          * @param int $pageId Page ID
1916          * @param int $revId Known current revision of this page
1917          * @return Revision|bool Returns false if missing
1918          * @since 1.28
1919          */
1920         public static function newKnownCurrent( IDatabase $db, $pageId, $revId ) {
1921                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1922                 return $cache->getWithSetCallback(
1923                         // Page/rev IDs passed in from DB to reflect history merges
1924                         $cache->makeGlobalKey( 'revision', $db->getWikiID(), $pageId, $revId ),
1925                         $cache::TTL_WEEK,
1926                         function ( $curValue, &$ttl, array &$setOpts ) use ( $db, $pageId, $revId ) {
1927                                 $setOpts += Database::getCacheSetOptions( $db );
1928
1929                                 $rev = Revision::loadFromPageId( $db, $pageId, $revId );
1930                                 // Reflect revision deletion and user renames
1931                                 if ( $rev ) {
1932                                         $rev->mTitle = null; // mutable; lazy-load
1933                                         $rev->mRefreshMutableFields = true;
1934                                 }
1935
1936                                 return $rev ?: false; // don't cache negatives
1937                         }
1938                 );
1939         }
1940
1941         /**
1942          * For cached revisions, make sure the user name and rev_deleted is up-to-date
1943          */
1944         private function loadMutableFields() {
1945                 if ( !$this->mRefreshMutableFields ) {
1946                         return; // not needed
1947                 }
1948
1949                 $this->mRefreshMutableFields = false;
1950                 $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
1951                 $row = $dbr->selectRow(
1952                         [ 'revision', 'user' ],
1953                         [ 'rev_deleted', 'user_name' ],
1954                         [ 'rev_id' => $this->mId, 'user_id = rev_user' ],
1955                         __METHOD__
1956                 );
1957                 if ( $row ) { // update values
1958                         $this->mDeleted = (int)$row->rev_deleted;
1959                         $this->mUserText = $row->user_name;
1960                 }
1961         }
1962 }