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\Database;
  24 use Wikimedia\Rdbms\IDatabase;
  25 use MediaWiki\Linker\LinkTarget;
  26 use MediaWiki\MediaWikiServices;
  27 use Wikimedia\Rdbms\ResultWrapper;
  28 use Wikimedia\Rdbms\FakeResultWrapper;
  29
  30 /**
  31  * @todo document
  32  */
  33 class Revision implements IDBAccessObject {
  34         /** @var int|null */
  35         protected $mId;
  36         /** @var int|null */
  37         protected $mPage;
  38         /** @var string */
  39         protected $mUserText;
  40         /** @var string */
  41         protected $mOrigUserText;
  42         /** @var int */
  43         protected $mUser;
  44         /** @var bool */
  45         protected $mMinorEdit;
  46         /** @var string */
  47         protected $mTimestamp;
  48         /** @var int */
  49         protected $mDeleted;
  50         /** @var int */
  51         protected $mSize;
  52         /** @var string */
  53         protected $mSha1;
  54         /** @var int */
  55         protected $mParentId;
  56         /** @var string */
  57         protected $mComment;
  58         /** @var string */
  59         protected $mText;
  60         /** @var int */
  61         protected $mTextId;
  62         /** @var int */
  63         protected $mUnpatrolled;
  64
  65         /** @var stdClass|null */
  66         protected $mTextRow;
  67
  68         /**  @var null|Title */
  69         protected $mTitle;
  70         /** @var bool */
  71         protected $mCurrent;
  72         /** @var string */
  73         protected $mContentModel;
  74         /** @var string */
  75         protected $mContentFormat;
  76
  77         /** @var Content|null|bool */
  78         protected $mContent;
  79         /** @var null|ContentHandler */
  80         protected $mContentHandler;
  81
  82         /** @var int */
  83         protected $mQueryFlags = 0;
  84         /** @var bool Used for cached values to reload user text and rev_deleted */
  85         protected $mRefreshMutableFields = false;
  86         /** @var string Wiki ID; false means the current wiki */
  87         protected $mWiki = false;
  88
  89         // Revision deletion constants
  90         const DELETED_TEXT = 1;
  91         const DELETED_COMMENT = 2;
  92         const DELETED_USER = 4;
  93         const DELETED_RESTRICTED = 8;
  94         const SUPPRESSED_USER = 12; // convenience
  95         const SUPPRESSED_ALL = 15; // convenience
  96
  97         // Audience options for accessors
  98         const FOR_PUBLIC = 1;
  99         const FOR_THIS_USER = 2;
 100         const RAW = 3;
 101
 102         const TEXT_CACHE_GROUP = 'revisiontext:10'; // process cache name and max key count
 103
 104         /**
 105          * Load a page revision from a given revision ID number.
 106          * Returns null if no such revision can be found.
 107          *
 108          * $flags include:
 109          *      Revision::READ_LATEST  : Select the data from the master
 110          *      Revision::READ_LOCKING : Select & lock the data from the master
 111          *
 112          * @param int $id
 113          * @param int $flags (optional)
 114          * @return Revision|null
 115          */
 116         public static function newFromId( $id, $flags = 0 ) {
 117                 return self::newFromConds( [ 'rev_id' => intval( $id ) ], $flags );
 118         }
 119
 120         /**
 121          * Load either the current, or a specified, revision
 122          * that's attached to a given link target. If not attached
 123          * to that link target, will return null.
 124          *
 125          * $flags include:
 126          *      Revision::READ_LATEST  : Select the data from the master
 127          *      Revision::READ_LOCKING : Select & lock the data from the master
 128          *
 129          * @param LinkTarget $linkTarget
 130          * @param int $id (optional)
 131          * @param int $flags Bitfield (optional)
 132          * @return Revision|null
 133          */
 134         public static function newFromTitle( LinkTarget $linkTarget, $id = 0, $flags = 0 ) {
 135                 $conds = [
 136                         'page_namespace' => $linkTarget->getNamespace(),
 137                         'page_title' => $linkTarget->getDBkey()
 138                 ];
 139                 if ( $id ) {
 140                         // Use the specified ID
 141                         $conds['rev_id'] = $id;
 142                         return self::newFromConds( $conds, $flags );
 143                 } else {
 144                         // Use a join to get the latest revision
 145                         $conds[] = 'rev_id=page_latest';
 146                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 147                         return self::loadFromConds( $db, $conds, $flags );
 148                 }
 149         }
 150
 151         /**
 152          * Load either the current, or a specified, revision
 153          * that's attached to a given page ID.
 154          * Returns null if no such revision can be found.
 155          *
 156          * $flags include:
 157          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 158          *      Revision::READ_LOCKING : Select & lock the data from the master
 159          *
 160          * @param int $pageId
 161          * @param int $revId (optional)
 162          * @param int $flags Bitfield (optional)
 163          * @return Revision|null
 164          */
 165         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 166                 $conds = [ 'page_id' => $pageId ];
 167                 if ( $revId ) {
 168                         $conds['rev_id'] = $revId;
 169                         return self::newFromConds( $conds, $flags );
 170                 } else {
 171                         // Use a join to get the latest revision
 172                         $conds[] = 'rev_id = page_latest';
 173                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 174                         return self::loadFromConds( $db, $conds, $flags );
 175                 }
 176         }
 177
 178         /**
 179          * Make a fake revision object from an archive table row. This is queried
 180          * for permissions or even inserted (as in Special:Undelete)
 181          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 182          *
 183          * @param object $row
 184          * @param array $overrides
 185          *
 186          * @throws MWException
 187          * @return Revision
 188          */
 189         public static function newFromArchiveRow( $row, $overrides = [] ) {
 190                 global $wgContentHandlerUseDB;
 191
 192                 $attribs = $overrides + [
 193                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 194                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 195                         'comment'    => $row->ar_comment,
 196                         'user'       => $row->ar_user,
 197                         'user_text'  => $row->ar_user_text,
 198                         'timestamp'  => $row->ar_timestamp,
 199                         'minor_edit' => $row->ar_minor_edit,
 200                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 201                         'deleted'    => $row->ar_deleted,
 202                         'len'        => $row->ar_len,
 203                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 204                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 205                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 206                 ];
 207
 208                 if ( !$wgContentHandlerUseDB ) {
 209                         unset( $attribs['content_model'] );
 210                         unset( $attribs['content_format'] );
 211                 }
 212
 213                 if ( !isset( $attribs['title'] )
 214                         && isset( $row->ar_namespace )
 215                         && isset( $row->ar_title )
 216                 ) {
 217                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 218                 }
 219
 220                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 221                         // Pre-1.5 ar_text row
 222                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 223                         if ( $attribs['text'] === false ) {
 224                                 throw new MWException( 'Unable to load text from archive row (possibly T24624)' );
 225                         }
 226                 }
 227                 return new self( $attribs );
 228         }
 229
 230         /**
 231          * @since 1.19
 232          *
 233          * @param object $row
 234          * @return Revision
 235          */
 236         public static function newFromRow( $row ) {
 237                 return new self( $row );
 238         }
 239
 240         /**
 241          * Load a page revision from a given revision ID number.
 242          * Returns null if no such revision can be found.
 243          *
 244          * @param IDatabase $db
 245          * @param int $id
 246          * @return Revision|null
 247          */
 248         public static function loadFromId( $db, $id ) {
 249                 return self::loadFromConds( $db, [ 'rev_id' => intval( $id ) ] );
 250         }
 251
 252         /**
 253          * Load either the current, or a specified, revision
 254          * that's attached to a given page. If not attached
 255          * to that page, will return null.
 256          *
 257          * @param IDatabase $db
 258          * @param int $pageid
 259          * @param int $id
 260          * @return Revision|null
 261          */
 262         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 263                 $conds = [ 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) ];
 264                 if ( $id ) {
 265                         $conds['rev_id'] = intval( $id );
 266                 } else {
 267                         $conds[] = 'rev_id=page_latest';
 268                 }
 269                 return self::loadFromConds( $db, $conds );
 270         }
 271
 272         /**
 273          * Load either the current, or a specified, revision
 274          * that's attached to a given page. If not attached
 275          * to that page, will return null.
 276          *
 277          * @param IDatabase $db
 278          * @param Title $title
 279          * @param int $id
 280          * @return Revision|null
 281          */
 282         public static function loadFromTitle( $db, $title, $id = 0 ) {
 283                 if ( $id ) {
 284                         $matchId = intval( $id );
 285                 } else {
 286                         $matchId = 'page_latest';
 287                 }
 288                 return self::loadFromConds( $db,
 289                         [
 290                                 "rev_id=$matchId",
 291                                 'page_namespace' => $title->getNamespace(),
 292                                 'page_title' => $title->getDBkey()
 293                         ]
 294                 );
 295         }
 296
 297         /**
 298          * Load the revision for the given title with the given timestamp.
 299          * WARNING: Timestamps may in some circumstances not be unique,
 300          * so this isn't the best key to use.
 301          *
 302          * @param IDatabase $db
 303          * @param Title $title
 304          * @param string $timestamp
 305          * @return Revision|null
 306          */
 307         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 308                 return self::loadFromConds( $db,
 309                         [
 310                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 311                                 'page_namespace' => $title->getNamespace(),
 312                                 'page_title' => $title->getDBkey()
 313                         ]
 314                 );
 315         }
 316
 317         /**
 318          * Given a set of conditions, fetch a revision
 319          *
 320          * This method is used then a revision ID is qualified and
 321          * will incorporate some basic replica DB/master fallback logic
 322          *
 323          * @param array $conditions
 324          * @param int $flags (optional)
 325          * @return Revision|null
 326          */
 327         private static function newFromConds( $conditions, $flags = 0 ) {
 328                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 329
 330                 $rev = self::loadFromConds( $db, $conditions, $flags );
 331                 // Make sure new pending/committed revision are visibile later on
 332                 // within web requests to certain avoid bugs like T93866 and T94407.
 333                 if ( !$rev
 334                         && !( $flags & self::READ_LATEST )
 335                         && wfGetLB()->getServerCount() > 1
 336                         && wfGetLB()->hasOrMadeRecentMasterChanges()
 337                 ) {
 338                         $flags = self::READ_LATEST;
 339                         $db = wfGetDB( DB_MASTER );
 340                         $rev = self::loadFromConds( $db, $conditions, $flags );
 341                 }
 342
 343                 if ( $rev ) {
 344                         $rev->mQueryFlags = $flags;
 345                 }
 346
 347                 return $rev;
 348         }
 349
 350         /**
 351          * Given a set of conditions, fetch a revision from
 352          * the given database connection.
 353          *
 354          * @param IDatabase $db
 355          * @param array $conditions
 356          * @param int $flags (optional)
 357          * @return Revision|null
 358          */
 359         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 360                 $row = self::fetchFromConds( $db, $conditions, $flags );
 361                 if ( $row ) {
 362                         $rev = new Revision( $row );
 363                         $rev->mWiki = $db->getWikiID();
 364
 365                         return $rev;
 366                 }
 367
 368                 return null;
 369         }
 370
 371         /**
 372          * Return a wrapper for a series of database rows to
 373          * fetch all of a given page's revisions in turn.
 374          * Each row can be fed to the constructor to get objects.
 375          *
 376          * @param LinkTarget $title
 377          * @return ResultWrapper
 378          * @deprecated Since 1.28
 379          */
 380         public static function fetchRevision( LinkTarget $title ) {
 381                 $row = self::fetchFromConds(
 382                         wfGetDB( DB_REPLICA ),
 383                         [
 384                                 'rev_id=page_latest',
 385                                 'page_namespace' => $title->getNamespace(),
 386                                 'page_title' => $title->getDBkey()
 387                         ]
 388                 );
 389
 390                 return new FakeResultWrapper( $row ? [ $row ] : [] );
 391         }
 392
 393         /**
 394          * Given a set of conditions, return a ResultWrapper
 395          * which will return matching database rows with the
 396          * fields necessary to build Revision objects.
 397          *
 398          * @param IDatabase $db
 399          * @param array $conditions
 400          * @param int $flags (optional)
 401          * @return stdClass
 402          */
 403         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 404                 $fields = array_merge(
 405                         self::selectFields(),
 406                         self::selectPageFields(),
 407                         self::selectUserFields()
 408                 );
 409                 $options = [];
 410                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 411                         $options[] = 'FOR UPDATE';
 412                 }
 413                 return $db->selectRow(
 414                         [ 'revision', 'page', 'user' ],
 415                         $fields,
 416                         $conditions,
 417                         __METHOD__,
 418                         $options,
 419                         [ 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() ]
 420                 );
 421         }
 422
 423         /**
 424          * Return the value of a select() JOIN conds array for the user table.
 425          * This will get user table rows for logged-in users.
 426          * @since 1.19
 427          * @return array
 428          */
 429         public static function userJoinCond() {
 430                 return [ 'LEFT JOIN', [ 'rev_user != 0', 'user_id = rev_user' ] ];
 431         }
 432
 433         /**
 434          * Return the value of a select() page conds array for the page table.
 435          * This will assure that the revision(s) are not orphaned from live pages.
 436          * @since 1.19
 437          * @return array
 438          */
 439         public static function pageJoinCond() {
 440                 return [ 'INNER JOIN', [ 'page_id = rev_page' ] ];
 441         }
 442
 443         /**
 444          * Return the list of revision fields that should be selected to create
 445          * a new revision.
 446          * @return array
 447          */
 448         public static function selectFields() {
 449                 global $wgContentHandlerUseDB;
 450
 451                 $fields = [
 452                         'rev_id',
 453                         'rev_page',
 454                         'rev_text_id',
 455                         'rev_timestamp',
 456                         'rev_comment',
 457                         'rev_user_text',
 458                         'rev_user',
 459                         'rev_minor_edit',
 460                         'rev_deleted',
 461                         'rev_len',
 462                         'rev_parent_id',
 463                         'rev_sha1',
 464                 ];
 465
 466                 if ( $wgContentHandlerUseDB ) {
 467                         $fields[] = 'rev_content_format';
 468                         $fields[] = 'rev_content_model';
 469                 }
 470
 471                 return $fields;
 472         }
 473
 474         /**
 475          * Return the list of revision fields that should be selected to create
 476          * a new revision from an archive row.
 477          * @return array
 478          */
 479         public static function selectArchiveFields() {
 480                 global $wgContentHandlerUseDB;
 481                 $fields = [
 482                         'ar_id',
 483                         'ar_page_id',
 484                         'ar_rev_id',
 485                         'ar_text',
 486                         'ar_text_id',
 487                         'ar_timestamp',
 488                         'ar_comment',
 489                         'ar_user_text',
 490                         'ar_user',
 491                         'ar_minor_edit',
 492                         'ar_deleted',
 493                         'ar_len',
 494                         'ar_parent_id',
 495                         'ar_sha1',
 496                 ];
 497
 498                 if ( $wgContentHandlerUseDB ) {
 499                         $fields[] = 'ar_content_format';
 500                         $fields[] = 'ar_content_model';
 501                 }
 502                 return $fields;
 503         }
 504
 505         /**
 506          * Return the list of text fields that should be selected to read the
 507          * revision text
 508          * @return array
 509          */
 510         public static function selectTextFields() {
 511                 return [
 512                         'old_text',
 513                         'old_flags'
 514                 ];
 515         }
 516
 517         /**
 518          * Return the list of page fields that should be selected from page table
 519          * @return array
 520          */
 521         public static function selectPageFields() {
 522                 return [
 523                         'page_namespace',
 524                         'page_title',
 525                         'page_id',
 526                         'page_latest',
 527                         'page_is_redirect',
 528                         'page_len',
 529                 ];
 530         }
 531
 532         /**
 533          * Return the list of user fields that should be selected from user table
 534          * @return array
 535          */
 536         public static function selectUserFields() {
 537                 return [ 'user_name' ];
 538         }
 539
 540         /**
 541          * Do a batched query to get the parent revision lengths
 542          * @param IDatabase $db
 543          * @param array $revIds
 544          * @return array
 545          */
 546         public static function getParentLengths( $db, array $revIds ) {
 547                 $revLens = [];
 548                 if ( !$revIds ) {
 549                         return $revLens; // empty
 550                 }
 551                 $res = $db->select( 'revision',
 552                         [ 'rev_id', 'rev_len' ],
 553                         [ 'rev_id' => $revIds ],
 554                         __METHOD__ );
 555                 foreach ( $res as $row ) {
 556                         $revLens[$row->rev_id] = $row->rev_len;
 557                 }
 558                 return $revLens;
 559         }
 560
 561         /**
 562          * Constructor
 563          *
 564          * @param object|array $row Either a database row or an array
 565          * @throws MWException
 566          * @access private
 567          */
 568         function __construct( $row ) {
 569                 if ( is_object( $row ) ) {
 570                         $this->mId = intval( $row->rev_id );
 571                         $this->mPage = intval( $row->rev_page );
 572                         $this->mTextId = intval( $row->rev_text_id );
 573                         $this->mComment = $row->rev_comment;
 574                         $this->mUser = intval( $row->rev_user );
 575                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 576                         $this->mTimestamp = $row->rev_timestamp;
 577                         $this->mDeleted = intval( $row->rev_deleted );
 578
 579                         if ( !isset( $row->rev_parent_id ) ) {
 580                                 $this->mParentId = null;
 581                         } else {
 582                                 $this->mParentId = intval( $row->rev_parent_id );
 583                         }
 584
 585                         if ( !isset( $row->rev_len ) ) {
 586                                 $this->mSize = null;
 587                         } else {
 588                                 $this->mSize = intval( $row->rev_len );
 589                         }
 590
 591                         if ( !isset( $row->rev_sha1 ) ) {
 592                                 $this->mSha1 = null;
 593                         } else {
 594                                 $this->mSha1 = $row->rev_sha1;
 595                         }
 596
 597                         if ( isset( $row->page_latest ) ) {
 598                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 599                                 $this->mTitle = Title::newFromRow( $row );
 600                         } else {
 601                                 $this->mCurrent = false;
 602                                 $this->mTitle = null;
 603                         }
 604
 605                         if ( !isset( $row->rev_content_model ) ) {
 606                                 $this->mContentModel = null; # determine on demand if needed
 607                         } else {
 608                                 $this->mContentModel = strval( $row->rev_content_model );
 609                         }
 610
 611                         if ( !isset( $row->rev_content_format ) ) {
 612                                 $this->mContentFormat = null; # determine on demand if needed
 613                         } else {
 614                                 $this->mContentFormat = strval( $row->rev_content_format );
 615                         }
 616
 617                         // Lazy extraction...
 618                         $this->mText = null;
 619                         if ( isset( $row->old_text ) ) {
 620                                 $this->mTextRow = $row;
 621                         } else {
 622                                 // 'text' table row entry will be lazy-loaded
 623                                 $this->mTextRow = null;
 624                         }
 625
 626                         // Use user_name for users and rev_user_text for IPs...
 627                         $this->mUserText = null; // lazy load if left null
 628                         if ( $this->mUser == 0 ) {
 629                                 $this->mUserText = $row->rev_user_text; // IP user
 630                         } elseif ( isset( $row->user_name ) ) {
 631                                 $this->mUserText = $row->user_name; // logged-in user
 632                         }
 633                         $this->mOrigUserText = $row->rev_user_text;
 634                 } elseif ( is_array( $row ) ) {
 635                         // Build a new revision to be saved...
 636                         global $wgUser; // ugh
 637
 638                         # if we have a content object, use it to set the model and type
 639                         if ( !empty( $row['content'] ) ) {
 640                                 // @todo when is that set? test with external store setup! check out insertOn() [dk]
 641                                 if ( !empty( $row['text_id'] ) ) {
 642                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 643                                                 "can't serialize content object" );
 644                                 }
 645
 646                                 $row['content_model'] = $row['content']->getModel();
 647                                 # note: mContentFormat is initializes later accordingly
 648                                 # note: content is serialized later in this method!
 649                                 # also set text to null?
 650                         }
 651
 652                         $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 653                         $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 654                         $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 655                         $this->mUserText = isset( $row['user_text'] )
 656                                 ? strval( $row['user_text'] ) : $wgUser->getName();
 657                         $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 658                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 659                         $this->mTimestamp = isset( $row['timestamp'] )
 660                                 ? strval( $row['timestamp'] ) : wfTimestampNow();
 661                         $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 662                         $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 663                         $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 664                         $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 665
 666                         $this->mContentModel = isset( $row['content_model'] )
 667                                 ? strval( $row['content_model'] ) : null;
 668                         $this->mContentFormat = isset( $row['content_format'] )
 669                                 ? strval( $row['content_format'] ) : null;
 670
 671                         // Enforce spacing trimming on supplied text
 672                         $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 673                         $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 674                         $this->mTextRow = null;
 675
 676                         $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 677
 678                         // if we have a Content object, override mText and mContentModel
 679                         if ( !empty( $row['content'] ) ) {
 680                                 if ( !( $row['content'] instanceof Content ) ) {
 681                                         throw new MWException( '`content` field must contain a Content object.' );
 682                                 }
 683
 684                                 $handler = $this->getContentHandler();
 685                                 $this->mContent = $row['content'];
 686
 687                                 $this->mContentModel = $this->mContent->getModel();
 688                                 $this->mContentHandler = null;
 689
 690                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 691                         } elseif ( $this->mText !== null ) {
 692                                 $handler = $this->getContentHandler();
 693                                 $this->mContent = $handler->unserializeContent( $this->mText );
 694                         }
 695
 696                         // If we have a Title object, make sure it is consistent with mPage.
 697                         if ( $this->mTitle && $this->mTitle->exists() ) {
 698                                 if ( $this->mPage === null ) {
 699                                         // if the page ID wasn't known, set it now
 700                                         $this->mPage = $this->mTitle->getArticleID();
 701                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 702                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 703                                         // but it seems worth mentioning it in the log.
 704                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 705                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 706                                 }
 707                         }
 708
 709                         $this->mCurrent = false;
 710
 711                         // If we still have no length, see it we have the text to figure it out
 712                         if ( !$this->mSize && $this->mContent !== null ) {
 713                                 $this->mSize = $this->mContent->getSize();
 714                         }
 715
 716                         // Same for sha1
 717                         if ( $this->mSha1 === null ) {
 718                                 $this->mSha1 = $this->mText === null ? null : self::base36Sha1( $this->mText );
 719                         }
 720
 721                         // force lazy init
 722                         $this->getContentModel();
 723                         $this->getContentFormat();
 724                 } else {
 725                         throw new MWException( 'Revision constructor passed invalid row format.' );
 726                 }
 727                 $this->mUnpatrolled = null;
 728         }
 729
 730         /**
 731          * Get revision ID
 732          *
 733          * @return int|null
 734          */
 735         public function getId() {
 736                 return $this->mId;
 737         }
 738
 739         /**
 740          * Set the revision ID
 741          *
 742          * This should only be used for proposed revisions that turn out to be null edits
 743          *
 744          * @since 1.19
 745          * @param int $id
 746          */
 747         public function setId( $id ) {
 748                 $this->mId = (int)$id;
 749         }
 750
 751         /**
 752          * Set the user ID/name
 753          *
 754          * This should only be used for proposed revisions that turn out to be null edits
 755          *
 756          * @since 1.28
 757          * @param integer $id User ID
 758          * @param string $name User name
 759          */
 760         public function setUserIdAndName( $id, $name ) {
 761                 $this->mUser = (int)$id;
 762                 $this->mUserText = $name;
 763                 $this->mOrigUserText = $name;
 764         }
 765
 766         /**
 767          * Get text row ID
 768          *
 769          * @return int|null
 770          */
 771         public function getTextId() {
 772                 return $this->mTextId;
 773         }
 774
 775         /**
 776          * Get parent revision ID (the original previous page revision)
 777          *
 778          * @return int|null
 779          */
 780         public function getParentId() {
 781                 return $this->mParentId;
 782         }
 783
 784         /**
 785          * Returns the length of the text in this revision, or null if unknown.
 786          *
 787          * @return int|null
 788          */
 789         public function getSize() {
 790                 return $this->mSize;
 791         }
 792
 793         /**
 794          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 795          *
 796          * @return string|null
 797          */
 798         public function getSha1() {
 799                 return $this->mSha1;
 800         }
 801
 802         /**
 803          * Returns the title of the page associated with this entry or null.
 804          *
 805          * Will do a query, when title is not set and id is given.
 806          *
 807          * @return Title|null
 808          */
 809         public function getTitle() {
 810                 if ( $this->mTitle !== null ) {
 811                         return $this->mTitle;
 812                 }
 813                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 814                 if ( $this->mId !== null ) {
 815                         $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
 816                         $row = $dbr->selectRow(
 817                                 [ 'page', 'revision' ],
 818                                 self::selectPageFields(),
 819                                 [ 'page_id=rev_page', 'rev_id' => $this->mId ],
 820                                 __METHOD__
 821                         );
 822                         if ( $row ) {
 823                                 // @TODO: better foreign title handling
 824                                 $this->mTitle = Title::newFromRow( $row );
 825                         }
 826                 }
 827
 828                 if ( $this->mWiki === false || $this->mWiki === wfWikiID() ) {
 829                         // Loading by ID is best, though not possible for foreign titles
 830                         if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 831                                 $this->mTitle = Title::newFromID( $this->mPage );
 832                         }
 833                 }
 834
 835                 return $this->mTitle;
 836         }
 837
 838         /**
 839          * Set the title of the revision
 840          *
 841          * @param Title $title
 842          */
 843         public function setTitle( $title ) {
 844                 $this->mTitle = $title;
 845         }
 846
 847         /**
 848          * Get the page ID
 849          *
 850          * @return int|null
 851          */
 852         public function getPage() {
 853                 return $this->mPage;
 854         }
 855
 856         /**
 857          * Fetch revision's user id if it's available to the specified audience.
 858          * If the specified audience does not have access to it, zero will be
 859          * returned.
 860          *
 861          * @param int $audience One of:
 862          *   Revision::FOR_PUBLIC       to be displayed to all users
 863          *   Revision::FOR_THIS_USER    to be displayed to the given user
 864          *   Revision::RAW              get the ID regardless of permissions
 865          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 866          *   to the $audience parameter
 867          * @return int
 868          */
 869         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 870                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 871                         return 0;
 872                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 873                         return 0;
 874                 } else {
 875                         return $this->mUser;
 876                 }
 877         }
 878
 879         /**
 880          * Fetch revision's user id without regard for the current user's permissions
 881          *
 882          * @return int
 883          * @deprecated since 1.25, use getUser( Revision::RAW )
 884          */
 885         public function getRawUser() {
 886                 wfDeprecated( __METHOD__, '1.25' );
 887                 return $this->getUser( self::RAW );
 888         }
 889
 890         /**
 891          * Fetch revision's username if it's available to the specified audience.
 892          * If the specified audience does not have access to the username, an
 893          * empty string will be returned.
 894          *
 895          * @param int $audience One of:
 896          *   Revision::FOR_PUBLIC       to be displayed to all users
 897          *   Revision::FOR_THIS_USER    to be displayed to the given user
 898          *   Revision::RAW              get the text regardless of permissions
 899          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 900          *   to the $audience parameter
 901          * @return string
 902          */
 903         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 904                 $this->loadMutableFields();
 905
 906                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 907                         return '';
 908                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 909                         return '';
 910                 } else {
 911                         if ( $this->mUserText === null ) {
 912                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 913                                 if ( $this->mUserText === false ) {
 914                                         # This shouldn't happen, but it can if the wiki was recovered
 915                                         # via importing revs and there is no user table entry yet.
 916                                         $this->mUserText = $this->mOrigUserText;
 917                                 }
 918                         }
 919                         return $this->mUserText;
 920                 }
 921         }
 922
 923         /**
 924          * Fetch revision's username without regard for view restrictions
 925          *
 926          * @return string
 927          * @deprecated since 1.25, use getUserText( Revision::RAW )
 928          */
 929         public function getRawUserText() {
 930                 wfDeprecated( __METHOD__, '1.25' );
 931                 return $this->getUserText( self::RAW );
 932         }
 933
 934         /**
 935          * Fetch revision comment if it's available to the specified audience.
 936          * If the specified audience does not have access to the comment, an
 937          * empty string will be returned.
 938          *
 939          * @param int $audience One of:
 940          *   Revision::FOR_PUBLIC       to be displayed to all users
 941          *   Revision::FOR_THIS_USER    to be displayed to the given user
 942          *   Revision::RAW              get the text regardless of permissions
 943          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 944          *   to the $audience parameter
 945          * @return string
 946          */
 947         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 948                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 949                         return '';
 950                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 951                         return '';
 952                 } else {
 953                         return $this->mComment;
 954                 }
 955         }
 956
 957         /**
 958          * Fetch revision comment without regard for the current user's permissions
 959          *
 960          * @return string
 961          * @deprecated since 1.25, use getComment( Revision::RAW )
 962          */
 963         public function getRawComment() {
 964                 wfDeprecated( __METHOD__, '1.25' );
 965                 return $this->getComment( self::RAW );
 966         }
 967
 968         /**
 969          * @return bool
 970          */
 971         public function isMinor() {
 972                 return (bool)$this->mMinorEdit;
 973         }
 974
 975         /**
 976          * @return int Rcid of the unpatrolled row, zero if there isn't one
 977          */
 978         public function isUnpatrolled() {
 979                 if ( $this->mUnpatrolled !== null ) {
 980                         return $this->mUnpatrolled;
 981                 }
 982                 $rc = $this->getRecentChange();
 983                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 984                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 985                 } else {
 986                         $this->mUnpatrolled = 0;
 987                 }
 988                 return $this->mUnpatrolled;
 989         }
 990
 991         /**
 992          * Get the RC object belonging to the current revision, if there's one
 993          *
 994          * @param int $flags (optional) $flags include:
 995          *      Revision::READ_LATEST  : Select the data from the master
 996          *
 997          * @since 1.22
 998          * @return RecentChange|null
 999          */
1000         public function getRecentChange( $flags = 0 ) {
1001                 $dbr = wfGetDB( DB_REPLICA );
1002
1003                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
1004
1005                 return RecentChange::newFromConds(
1006                         [
1007                                 'rc_user_text' => $this->getUserText( Revision::RAW ),
1008                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
1009                                 'rc_this_oldid' => $this->getId()
1010                         ],
1011                         __METHOD__,
1012                         $dbType
1013                 );
1014         }
1015
1016         /**
1017          * @param int $field One of DELETED_* bitfield constants
1018          *
1019          * @return bool
1020          */
1021         public function isDeleted( $field ) {
1022                 if ( $this->isCurrent() && $field === self::DELETED_TEXT ) {
1023                         // Current revisions of pages cannot have the content hidden. Skipping this
1024                         // check is very useful for Parser as it fetches templates using newKnownCurrent().
1025                         // Calling getVisibility() in that case triggers a verification database query.
1026                         return false; // no need to check
1027                 }
1028
1029                 return ( $this->getVisibility() & $field ) == $field;
1030         }
1031
1032         /**
1033          * Get the deletion bitfield of the revision
1034          *
1035          * @return int
1036          */
1037         public function getVisibility() {
1038                 $this->loadMutableFields();
1039
1040                 return (int)$this->mDeleted;
1041         }
1042
1043         /**
1044          * Fetch revision content if it's available to the specified audience.
1045          * If the specified audience does not have the ability to view this
1046          * revision, null will be returned.
1047          *
1048          * @param int $audience One of:
1049          *   Revision::FOR_PUBLIC       to be displayed to all users
1050          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1051          *   Revision::RAW              get the text regardless of permissions
1052          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1053          *   to the $audience parameter
1054          * @since 1.21
1055          * @return Content|null
1056          */
1057         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1058                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1059                         return null;
1060                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1061                         return null;
1062                 } else {
1063                         return $this->getContentInternal();
1064                 }
1065         }
1066
1067         /**
1068          * Get original serialized data (without checking view restrictions)
1069          *
1070          * @since 1.21
1071          * @return string
1072          */
1073         public function getSerializedData() {
1074                 if ( $this->mText === null ) {
1075                         // Revision is immutable. Load on demand.
1076                         $this->mText = $this->loadText();
1077                 }
1078
1079                 return $this->mText;
1080         }
1081
1082         /**
1083          * Gets the content object for the revision (or null on failure).
1084          *
1085          * Note that for mutable Content objects, each call to this method will return a
1086          * fresh clone.
1087          *
1088          * @since 1.21
1089          * @return Content|null The Revision's content, or null on failure.
1090          */
1091         protected function getContentInternal() {
1092                 if ( $this->mContent === null ) {
1093                         $text = $this->getSerializedData();
1094
1095                         if ( $text !== null && $text !== false ) {
1096                                 // Unserialize content
1097                                 $handler = $this->getContentHandler();
1098                                 $format = $this->getContentFormat();
1099
1100                                 $this->mContent = $handler->unserializeContent( $text, $format );
1101                         }
1102                 }
1103
1104                 // NOTE: copy() will return $this for immutable content objects
1105                 return $this->mContent ? $this->mContent->copy() : null;
1106         }
1107
1108         /**
1109          * Returns the content model for this revision.
1110          *
1111          * If no content model was stored in the database, the default content model for the title is
1112          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1113          * is used as a last resort.
1114          *
1115          * @return string The content model id associated with this revision,
1116          *     see the CONTENT_MODEL_XXX constants.
1117          */
1118         public function getContentModel() {
1119                 if ( !$this->mContentModel ) {
1120                         $title = $this->getTitle();
1121                         if ( $title ) {
1122                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1123                         } else {
1124                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1125                         }
1126
1127                         assert( !empty( $this->mContentModel ) );
1128                 }
1129
1130                 return $this->mContentModel;
1131         }
1132
1133         /**
1134          * Returns the content format for this revision.
1135          *
1136          * If no content format was stored in the database, the default format for this
1137          * revision's content model is returned.
1138          *
1139          * @return string The content format id associated with this revision,
1140          *     see the CONTENT_FORMAT_XXX constants.
1141          */
1142         public function getContentFormat() {
1143                 if ( !$this->mContentFormat ) {
1144                         $handler = $this->getContentHandler();
1145                         $this->mContentFormat = $handler->getDefaultFormat();
1146
1147                         assert( !empty( $this->mContentFormat ) );
1148                 }
1149
1150                 return $this->mContentFormat;
1151         }
1152
1153         /**
1154          * Returns the content handler appropriate for this revision's content model.
1155          *
1156          * @throws MWException
1157          * @return ContentHandler
1158          */
1159         public function getContentHandler() {
1160                 if ( !$this->mContentHandler ) {
1161                         $model = $this->getContentModel();
1162                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1163
1164                         $format = $this->getContentFormat();
1165
1166                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1167                                 throw new MWException( "Oops, the content format $format is not supported for "
1168                                         . "this content model, $model" );
1169                         }
1170                 }
1171
1172                 return $this->mContentHandler;
1173         }
1174
1175         /**
1176          * @return string
1177          */
1178         public function getTimestamp() {
1179                 return wfTimestamp( TS_MW, $this->mTimestamp );
1180         }
1181
1182         /**
1183          * @return bool
1184          */
1185         public function isCurrent() {
1186                 return $this->mCurrent;
1187         }
1188
1189         /**
1190          * Get previous revision for this title
1191          *
1192          * @return Revision|null
1193          */
1194         public function getPrevious() {
1195                 if ( $this->getTitle() ) {
1196                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1197                         if ( $prev ) {
1198                                 return self::newFromTitle( $this->getTitle(), $prev );
1199                         }
1200                 }
1201                 return null;
1202         }
1203
1204         /**
1205          * Get next revision for this title
1206          *
1207          * @return Revision|null
1208          */
1209         public function getNext() {
1210                 if ( $this->getTitle() ) {
1211                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1212                         if ( $next ) {
1213                                 return self::newFromTitle( $this->getTitle(), $next );
1214                         }
1215                 }
1216                 return null;
1217         }
1218
1219         /**
1220          * Get previous revision Id for this page_id
1221          * This is used to populate rev_parent_id on save
1222          *
1223          * @param IDatabase $db
1224          * @return int
1225          */
1226         private function getPreviousRevisionId( $db ) {
1227                 if ( $this->mPage === null ) {
1228                         return 0;
1229                 }
1230                 # Use page_latest if ID is not given
1231                 if ( !$this->mId ) {
1232                         $prevId = $db->selectField( 'page', 'page_latest',
1233                                 [ 'page_id' => $this->mPage ],
1234                                 __METHOD__ );
1235                 } else {
1236                         $prevId = $db->selectField( 'revision', 'rev_id',
1237                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1238                                 __METHOD__,
1239                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1240                 }
1241                 return intval( $prevId );
1242         }
1243
1244         /**
1245          * Get revision text associated with an old or archive row
1246          *
1247          * Both the flags and the text field must be included. Including the old_id
1248          * field will activate cache usage as long as the $wiki parameter is not set.
1249          *
1250          * @param stdClass $row The text data
1251          * @param string $prefix Table prefix (default 'old_')
1252          * @param string|bool $wiki The name of the wiki to load the revision text from
1253          *   (same as the the wiki $row was loaded from) or false to indicate the local
1254          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1255          *   identifier as understood by the LoadBalancer class.
1256          * @return string|false Text the text requested or false on failure
1257          */
1258         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1259                 $textField = $prefix . 'text';
1260                 $flagsField = $prefix . 'flags';
1261
1262                 if ( isset( $row->$flagsField ) ) {
1263                         $flags = explode( ',', $row->$flagsField );
1264                 } else {
1265                         $flags = [];
1266                 }
1267
1268                 if ( isset( $row->$textField ) ) {
1269                         $text = $row->$textField;
1270                 } else {
1271                         return false;
1272                 }
1273
1274                 // Use external methods for external objects, text in table is URL-only then
1275                 if ( in_array( 'external', $flags ) ) {
1276                         $url = $text;
1277                         $parts = explode( '://', $url, 2 );
1278                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1279                                 return false;
1280                         }
1281
1282                         if ( isset( $row->old_id ) && $wiki === false ) {
1283                                 // Make use of the wiki-local revision text cache
1284                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1285                                 // The cached value should be decompressed, so handle that and return here
1286                                 return $cache->getWithSetCallback(
1287                                         $cache->makeKey( 'revisiontext', 'textid', $row->old_id ),
1288                                         self::getCacheTTL( $cache ),
1289                                         function () use ( $url, $wiki, $flags ) {
1290                                                 // No negative caching per Revision::loadText()
1291                                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1292
1293                                                 return self::decompressRevisionText( $text, $flags );
1294                                         },
1295                                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1296                                 );
1297                         } else {
1298                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1299                         }
1300                 }
1301
1302                 return self::decompressRevisionText( $text, $flags );
1303         }
1304
1305         /**
1306          * If $wgCompressRevisions is enabled, we will compress data.
1307          * The input string is modified in place.
1308          * Return value is the flags field: contains 'gzip' if the
1309          * data is compressed, and 'utf-8' if we're saving in UTF-8
1310          * mode.
1311          *
1312          * @param mixed $text Reference to a text
1313          * @return string
1314          */
1315         public static function compressRevisionText( &$text ) {
1316                 global $wgCompressRevisions;
1317                 $flags = [];
1318
1319                 # Revisions not marked this way will be converted
1320                 # on load if $wgLegacyCharset is set in the future.
1321                 $flags[] = 'utf-8';
1322
1323                 if ( $wgCompressRevisions ) {
1324                         if ( function_exists( 'gzdeflate' ) ) {
1325                                 $deflated = gzdeflate( $text );
1326
1327                                 if ( $deflated === false ) {
1328                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1329                                 } else {
1330                                         $text = $deflated;
1331                                         $flags[] = 'gzip';
1332                                 }
1333                         } else {
1334                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1335                         }
1336                 }
1337                 return implode( ',', $flags );
1338         }
1339
1340         /**
1341          * Re-converts revision text according to it's flags.
1342          *
1343          * @param mixed $text Reference to a text
1344          * @param array $flags Compression flags
1345          * @return string|bool Decompressed text, or false on failure
1346          */
1347         public static function decompressRevisionText( $text, $flags ) {
1348                 global $wgLegacyEncoding, $wgContLang;
1349
1350                 if ( $text === false ) {
1351                         // Text failed to be fetched; nothing to do
1352                         return false;
1353                 }
1354
1355                 if ( in_array( 'gzip', $flags ) ) {
1356                         # Deal with optional compression of archived pages.
1357                         # This can be done periodically via maintenance/compressOld.php, and
1358                         # as pages are saved if $wgCompressRevisions is set.
1359                         $text = gzinflate( $text );
1360
1361                         if ( $text === false ) {
1362                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1363                                 return false;
1364                         }
1365                 }
1366
1367                 if ( in_array( 'object', $flags ) ) {
1368                         # Generic compressed storage
1369                         $obj = unserialize( $text );
1370                         if ( !is_object( $obj ) ) {
1371                                 // Invalid object
1372                                 return false;
1373                         }
1374                         $text = $obj->getText();
1375                 }
1376
1377                 if ( $text !== false && $wgLegacyEncoding
1378                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1379                 ) {
1380                         # Old revisions kept around in a legacy encoding?
1381                         # Upconvert on demand.
1382                         # ("utf8" checked for compatibility with some broken
1383                         #  conversion scripts 2008-12-30)
1384                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1385                 }
1386
1387                 return $text;
1388         }
1389
1390         /**
1391          * Insert a new revision into the database, returning the new revision ID
1392          * number on success and dies horribly on failure.
1393          *
1394          * @param IDatabase $dbw (master connection)
1395          * @throws MWException
1396          * @return int
1397          */
1398         public function insertOn( $dbw ) {
1399                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1400
1401                 // We're inserting a new revision, so we have to use master anyway.
1402                 // If it's a null revision, it may have references to rows that
1403                 // are not in the replica yet (the text row).
1404                 $this->mQueryFlags |= self::READ_LATEST;
1405
1406                 // Not allowed to have rev_page equal to 0, false, etc.
1407                 if ( !$this->mPage ) {
1408                         $title = $this->getTitle();
1409                         if ( $title instanceof Title ) {
1410                                 $titleText = ' for page ' . $title->getPrefixedText();
1411                         } else {
1412                                 $titleText = '';
1413                         }
1414                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1415                 }
1416
1417                 $this->checkContentModel();
1418
1419                 $data = $this->mText;
1420                 $flags = self::compressRevisionText( $data );
1421
1422                 # Write to external storage if required
1423                 if ( $wgDefaultExternalStore ) {
1424                         // Store and get the URL
1425                         $data = ExternalStore::insertToDefault( $data );
1426                         if ( !$data ) {
1427                                 throw new MWException( "Unable to store text to external storage" );
1428                         }
1429                         if ( $flags ) {
1430                                 $flags .= ',';
1431                         }
1432                         $flags .= 'external';
1433                 }
1434
1435                 # Record the text (or external storage URL) to the text table
1436                 if ( $this->mTextId === null ) {
1437                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1438                         $dbw->insert( 'text',
1439                                 [
1440                                         'old_id' => $old_id,
1441                                         'old_text' => $data,
1442                                         'old_flags' => $flags,
1443                                 ], __METHOD__
1444                         );
1445                         $this->mTextId = $dbw->insertId();
1446                 }
1447
1448                 if ( $this->mComment === null ) {
1449                         $this->mComment = "";
1450                 }
1451
1452                 # Record the edit in revisions
1453                 $rev_id = $this->mId !== null
1454                         ? $this->mId
1455                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1456                 $row = [
1457                         'rev_id'         => $rev_id,
1458                         'rev_page'       => $this->mPage,
1459                         'rev_text_id'    => $this->mTextId,
1460                         'rev_comment'    => $this->mComment,
1461                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1462                         'rev_user'       => $this->mUser,
1463                         'rev_user_text'  => $this->mUserText,
1464                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1465                         'rev_deleted'    => $this->mDeleted,
1466                         'rev_len'        => $this->mSize,
1467                         'rev_parent_id'  => $this->mParentId === null
1468                                 ? $this->getPreviousRevisionId( $dbw )
1469                                 : $this->mParentId,
1470                         'rev_sha1'       => $this->mSha1 === null
1471                                 ? Revision::base36Sha1( $this->mText )
1472                                 : $this->mSha1,
1473                 ];
1474
1475                 if ( $wgContentHandlerUseDB ) {
1476                         // NOTE: Store null for the default model and format, to save space.
1477                         // XXX: Makes the DB sensitive to changed defaults.
1478                         // Make this behavior optional? Only in miser mode?
1479
1480                         $model = $this->getContentModel();
1481                         $format = $this->getContentFormat();
1482
1483                         $title = $this->getTitle();
1484
1485                         if ( $title === null ) {
1486                                 throw new MWException( "Insufficient information to determine the title of the "
1487                                         . "revision's page!" );
1488                         }
1489
1490                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1491                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1492
1493                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1494                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1495                 }
1496
1497                 $dbw->insert( 'revision', $row, __METHOD__ );
1498
1499                 if ( $this->mId === null ) {
1500                         // Only if nextSequenceValue() was called
1501                         $this->mId = $dbw->insertId();
1502                 }
1503
1504                 // Assertion to try to catch T92046
1505                 if ( (int)$this->mId === 0 ) {
1506                         throw new UnexpectedValueException(
1507                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1508                                         var_export( $row, 1 )
1509                         );
1510                 }
1511
1512                 // Avoid PHP 7.1 warning of passing $this by reference
1513                 $revision = $this;
1514                 Hooks::run( 'RevisionInsertComplete', [ &$revision, $data, $flags ] );
1515
1516                 return $this->mId;
1517         }
1518
1519         protected function checkContentModel() {
1520                 global $wgContentHandlerUseDB;
1521
1522                 // Note: may return null for revisions that have not yet been inserted
1523                 $title = $this->getTitle();
1524
1525                 $model = $this->getContentModel();
1526                 $format = $this->getContentFormat();
1527                 $handler = $this->getContentHandler();
1528
1529                 if ( !$handler->isSupportedFormat( $format ) ) {
1530                         $t = $title->getPrefixedDBkey();
1531
1532                         throw new MWException( "Can't use format $format with content model $model on $t" );
1533                 }
1534
1535                 if ( !$wgContentHandlerUseDB && $title ) {
1536                         // if $wgContentHandlerUseDB is not set,
1537                         // all revisions must use the default content model and format.
1538
1539                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1540                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1541                         $defaultFormat = $defaultHandler->getDefaultFormat();
1542
1543                         if ( $this->getContentModel() != $defaultModel ) {
1544                                 $t = $title->getPrefixedDBkey();
1545
1546                                 throw new MWException( "Can't save non-default content model with "
1547                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1548                                         . "default for $t is $defaultModel" );
1549                         }
1550
1551                         if ( $this->getContentFormat() != $defaultFormat ) {
1552                                 $t = $title->getPrefixedDBkey();
1553
1554                                 throw new MWException( "Can't use non-default content format with "
1555                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1556                                         . "default for $t is $defaultFormat" );
1557                         }
1558                 }
1559
1560                 $content = $this->getContent( Revision::RAW );
1561                 $prefixedDBkey = $title->getPrefixedDBkey();
1562                 $revId = $this->mId;
1563
1564                 if ( !$content ) {
1565                         throw new MWException(
1566                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1567                         );
1568                 }
1569                 if ( !$content->isValid() ) {
1570                         throw new MWException(
1571                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1572                         );
1573                 }
1574         }
1575
1576         /**
1577          * Get the base 36 SHA-1 value for a string of text
1578          * @param string $text
1579          * @return string
1580          */
1581         public static function base36Sha1( $text ) {
1582                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1583         }
1584
1585         /**
1586          * Get the text cache TTL
1587          *
1588          * @param WANObjectCache $cache
1589          * @return integer
1590          */
1591         private static function getCacheTTL( WANObjectCache $cache ) {
1592                 global $wgRevisionCacheExpiry;
1593
1594                 if ( $cache->getQoS( $cache::ATTR_EMULATION ) <= $cache::QOS_EMULATION_SQL ) {
1595                         // Do not cache RDBMs blobs in...the RDBMs store
1596                         $ttl = $cache::TTL_UNCACHEABLE;
1597                 } else {
1598                         $ttl = $wgRevisionCacheExpiry ?: $cache::TTL_UNCACHEABLE;
1599                 }
1600
1601                 return $ttl;
1602         }
1603
1604         /**
1605          * Lazy-load the revision's text.
1606          * Currently hardcoded to the 'text' table storage engine.
1607          *
1608          * @return string|bool The revision's text, or false on failure
1609          */
1610         private function loadText() {
1611                 $cache = ObjectCache::getMainWANInstance();
1612
1613                 // No negative caching; negative hits on text rows may be due to corrupted replica DBs
1614                 return $cache->getWithSetCallback(
1615                         $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
1616                         self::getCacheTTL( $cache ),
1617                         function () {
1618                                 return $this->fetchText();
1619                         },
1620                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1621                 );
1622         }
1623
1624         private function fetchText() {
1625                 $textId = $this->getTextId();
1626
1627                 // If we kept data for lazy extraction, use it now...
1628                 if ( $this->mTextRow !== null ) {
1629                         $row = $this->mTextRow;
1630                         $this->mTextRow = null;
1631                 } else {
1632                         $row = null;
1633                 }
1634
1635                 // Callers doing updates will pass in READ_LATEST as usual. Since the text/blob tables
1636                 // do not normally get rows changed around, set READ_LATEST_IMMUTABLE in those cases.
1637                 $flags = $this->mQueryFlags;
1638                 $flags |= DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST )
1639                         ? self::READ_LATEST_IMMUTABLE
1640                         : 0;
1641
1642                 list( $index, $options, $fallbackIndex, $fallbackOptions ) =
1643                         DBAccessObjectUtils::getDBOptions( $flags );
1644
1645                 if ( !$row ) {
1646                         // Text data is immutable; check replica DBs first.
1647                         $row = wfGetDB( $index )->selectRow(
1648                                 'text',
1649                                 [ 'old_text', 'old_flags' ],
1650                                 [ 'old_id' => $textId ],
1651                                 __METHOD__,
1652                                 $options
1653                         );
1654                 }
1655
1656                 // Fallback to DB_MASTER in some cases if the row was not found
1657                 if ( !$row && $fallbackIndex !== null ) {
1658                         // Use FOR UPDATE if it was used to fetch this revision. This avoids missing the row
1659                         // due to REPEATABLE-READ. Also fallback to the master if READ_LATEST is provided.
1660                         $row = wfGetDB( $fallbackIndex )->selectRow(
1661                                 'text',
1662                                 [ 'old_text', 'old_flags' ],
1663                                 [ 'old_id' => $textId ],
1664                                 __METHOD__,
1665                                 $fallbackOptions
1666                         );
1667                 }
1668
1669                 if ( !$row ) {
1670                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1671                 }
1672
1673                 $text = self::getRevisionText( $row );
1674                 if ( $row && $text === false ) {
1675                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1676                 }
1677
1678                 return is_string( $text ) ? $text : false;
1679         }
1680
1681         /**
1682          * Create a new null-revision for insertion into a page's
1683          * history. This will not re-save the text, but simply refer
1684          * to the text from the previous version.
1685          *
1686          * Such revisions can for instance identify page rename
1687          * operations and other such meta-modifications.
1688          *
1689          * @param IDatabase $dbw
1690          * @param int $pageId ID number of the page to read from
1691          * @param string $summary Revision's summary
1692          * @param bool $minor Whether the revision should be considered as minor
1693          * @param User|null $user User object to use or null for $wgUser
1694          * @return Revision|null Revision or null on error
1695          */
1696         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1697                 global $wgContentHandlerUseDB, $wgContLang;
1698
1699                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1700                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1701
1702                 if ( $wgContentHandlerUseDB ) {
1703                         $fields[] = 'rev_content_model';
1704                         $fields[] = 'rev_content_format';
1705                 }
1706
1707                 $current = $dbw->selectRow(
1708                         [ 'page', 'revision' ],
1709                         $fields,
1710                         [
1711                                 'page_id' => $pageId,
1712                                 'page_latest=rev_id',
1713                         ],
1714                         __METHOD__,
1715                         [ 'FOR UPDATE' ] // T51581
1716                 );
1717
1718                 if ( $current ) {
1719                         if ( !$user ) {
1720                                 global $wgUser;
1721                                 $user = $wgUser;
1722                         }
1723
1724                         // Truncate for whole multibyte characters
1725                         $summary = $wgContLang->truncate( $summary, 255 );
1726
1727                         $row = [
1728                                 'page'       => $pageId,
1729                                 'user_text'  => $user->getName(),
1730                                 'user'       => $user->getId(),
1731                                 'comment'    => $summary,
1732                                 'minor_edit' => $minor,
1733                                 'text_id'    => $current->rev_text_id,
1734                                 'parent_id'  => $current->page_latest,
1735                                 'len'        => $current->rev_len,
1736                                 'sha1'       => $current->rev_sha1
1737                         ];
1738
1739                         if ( $wgContentHandlerUseDB ) {
1740                                 $row['content_model'] = $current->rev_content_model;
1741                                 $row['content_format'] = $current->rev_content_format;
1742                         }
1743
1744                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1745
1746                         $revision = new Revision( $row );
1747                 } else {
1748                         $revision = null;
1749                 }
1750
1751                 return $revision;
1752         }
1753
1754         /**
1755          * Determine if the current user is allowed to view a particular
1756          * field of this revision, if it's marked as deleted.
1757          *
1758          * @param int $field One of self::DELETED_TEXT,
1759          *                              self::DELETED_COMMENT,
1760          *                              self::DELETED_USER
1761          * @param User|null $user User object to check, or null to use $wgUser
1762          * @return bool
1763          */
1764         public function userCan( $field, User $user = null ) {
1765                 return self::userCanBitfield( $this->getVisibility(), $field, $user );
1766         }
1767
1768         /**
1769          * Determine if the current user is allowed to view a particular
1770          * field of this revision, if it's marked as deleted. This is used
1771          * by various classes to avoid duplication.
1772          *
1773          * @param int $bitfield Current field
1774          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1775          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1776          *                               self::DELETED_USER = File::DELETED_USER
1777          * @param User|null $user User object to check, or null to use $wgUser
1778          * @param Title|null $title A Title object to check for per-page restrictions on,
1779          *                          instead of just plain userrights
1780          * @return bool
1781          */
1782         public static function userCanBitfield( $bitfield, $field, User $user = null,
1783                 Title $title = null
1784         ) {
1785                 if ( $bitfield & $field ) { // aspect is deleted
1786                         if ( $user === null ) {
1787                                 global $wgUser;
1788                                 $user = $wgUser;
1789                         }
1790                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1791                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1792                         } elseif ( $field & self::DELETED_TEXT ) {
1793                                 $permissions = [ 'deletedtext' ];
1794                         } else {
1795                                 $permissions = [ 'deletedhistory' ];
1796                         }
1797                         $permissionlist = implode( ', ', $permissions );
1798                         if ( $title === null ) {
1799                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1800                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1801                         } else {
1802                                 $text = $title->getPrefixedText();
1803                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1804                                 foreach ( $permissions as $perm ) {
1805                                         if ( $title->userCan( $perm, $user ) ) {
1806                                                 return true;
1807                                         }
1808                                 }
1809                                 return false;
1810                         }
1811                 } else {
1812                         return true;
1813                 }
1814         }
1815
1816         /**
1817          * Get rev_timestamp from rev_id, without loading the rest of the row
1818          *
1819          * @param Title $title
1820          * @param int $id
1821          * @param int $flags
1822          * @return string|bool False if not found
1823          */
1824         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1825                 $db = ( $flags & self::READ_LATEST )
1826                         ? wfGetDB( DB_MASTER )
1827                         : wfGetDB( DB_REPLICA );
1828                 // Casting fix for databases that can't take '' for rev_id
1829                 if ( $id == '' ) {
1830                         $id = 0;
1831                 }
1832                 $conds = [ 'rev_id' => $id ];
1833                 $conds['rev_page'] = $title->getArticleID();
1834                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1835
1836                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
1837         }
1838
1839         /**
1840          * Get count of revisions per page...not very efficient
1841          *
1842          * @param IDatabase $db
1843          * @param int $id Page id
1844          * @return int
1845          */
1846         static function countByPageId( $db, $id ) {
1847                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
1848                         [ 'rev_page' => $id ], __METHOD__ );
1849                 if ( $row ) {
1850                         return $row->revCount;
1851                 }
1852                 return 0;
1853         }
1854
1855         /**
1856          * Get count of revisions per page...not very efficient
1857          *
1858          * @param IDatabase $db
1859          * @param Title $title
1860          * @return int
1861          */
1862         static function countByTitle( $db, $title ) {
1863                 $id = $title->getArticleID();
1864                 if ( $id ) {
1865                         return self::countByPageId( $db, $id );
1866                 }
1867                 return 0;
1868         }
1869
1870         /**
1871          * Check if no edits were made by other users since
1872          * the time a user started editing the page. Limit to
1873          * 50 revisions for the sake of performance.
1874          *
1875          * @since 1.20
1876          * @deprecated since 1.24
1877          *
1878          * @param IDatabase|int $db The Database to perform the check on. May be given as a
1879          *        Database object or a database identifier usable with wfGetDB.
1880          * @param int $pageId The ID of the page in question
1881          * @param int $userId The ID of the user in question
1882          * @param string $since Look at edits since this time
1883          *
1884          * @return bool True if the given user was the only one to edit since the given timestamp
1885          */
1886         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1887                 if ( !$userId ) {
1888                         return false;
1889                 }
1890
1891                 if ( is_int( $db ) ) {
1892                         $db = wfGetDB( $db );
1893                 }
1894
1895                 $res = $db->select( 'revision',
1896                         'rev_user',
1897                         [
1898                                 'rev_page' => $pageId,
1899                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1900                         ],
1901                         __METHOD__,
1902                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
1903                 foreach ( $res as $row ) {
1904                         if ( $row->rev_user != $userId ) {
1905                                 return false;
1906                         }
1907                 }
1908                 return true;
1909         }
1910
1911         /**
1912          * Load a revision based on a known page ID and current revision ID from the DB
1913          *
1914          * This method allows for the use of caching, though accessing anything that normally
1915          * requires permission checks (aside from the text) will trigger a small DB lookup.
1916          * The title will also be lazy loaded, though setTitle() can be used to preload it.
1917          *
1918          * @param IDatabase $db
1919          * @param int $pageId Page ID
1920          * @param int $revId Known current revision of this page
1921          * @return Revision|bool Returns false if missing
1922          * @since 1.28
1923          */
1924         public static function newKnownCurrent( IDatabase $db, $pageId, $revId ) {
1925                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1926                 return $cache->getWithSetCallback(
1927                         // Page/rev IDs passed in from DB to reflect history merges
1928                         $cache->makeGlobalKey( 'revision', $db->getWikiID(), $pageId, $revId ),
1929                         $cache::TTL_WEEK,
1930                         function ( $curValue, &$ttl, array &$setOpts ) use ( $db, $pageId, $revId ) {
1931                                 $setOpts += Database::getCacheSetOptions( $db );
1932
1933                                 $rev = Revision::loadFromPageId( $db, $pageId, $revId );
1934                                 // Reflect revision deletion and user renames
1935                                 if ( $rev ) {
1936                                         $rev->mTitle = null; // mutable; lazy-load
1937                                         $rev->mRefreshMutableFields = true;
1938                                 }
1939
1940                                 return $rev ?: false; // don't cache negatives
1941                         }
1942                 );
1943         }
1944
1945         /**
1946          * For cached revisions, make sure the user name and rev_deleted is up-to-date
1947          */
1948         private function loadMutableFields() {
1949                 if ( !$this->mRefreshMutableFields ) {
1950                         return; // not needed
1951                 }
1952
1953                 $this->mRefreshMutableFields = false;
1954                 $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
1955                 $row = $dbr->selectRow(
1956                         [ 'revision', 'user' ],
1957                         [ 'rev_deleted', 'user_name' ],
1958                         [ 'rev_id' => $this->mId, 'user_id = rev_user' ],
1959                         __METHOD__
1960                 );
1961                 if ( $row ) { // update values
1962                         $this->mDeleted = (int)$row->rev_deleted;
1963                         $this->mUserText = $row->user_name;
1964                 }
1965         }
1966 }