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 use MediaWiki\Linker\LinkTarget;
  23
  24 /**
  25  * @todo document
  26  */
  27 class Revision implements IDBAccessObject {
  28         protected $mId;
  29
  30         /**
  31          * @var int|null
  32          */
  33         protected $mPage;
  34         protected $mUserText;
  35         protected $mOrigUserText;
  36         protected $mUser;
  37         protected $mMinorEdit;
  38         protected $mTimestamp;
  39         protected $mDeleted;
  40         protected $mSize;
  41         protected $mSha1;
  42         protected $mParentId;
  43         protected $mComment;
  44         protected $mText;
  45         protected $mTextId;
  46
  47         /**
  48          * @var stdClass|null
  49          */
  50         protected $mTextRow;
  51
  52         /**
  53          * @var null|Title
  54          */
  55         protected $mTitle;
  56         protected $mCurrent;
  57         protected $mContentModel;
  58         protected $mContentFormat;
  59
  60         /**
  61          * @var Content|null|bool
  62          */
  63         protected $mContent;
  64
  65         /**
  66          * @var null|ContentHandler
  67          */
  68         protected $mContentHandler;
  69
  70         /**
  71          * @var int
  72          */
  73         protected $mQueryFlags = 0;
  74
  75         // Revision deletion constants
  76         const DELETED_TEXT = 1;
  77         const DELETED_COMMENT = 2;
  78         const DELETED_USER = 4;
  79         const DELETED_RESTRICTED = 8;
  80         const SUPPRESSED_USER = 12; // convenience
  81
  82         // Audience options for accessors
  83         const FOR_PUBLIC = 1;
  84         const FOR_THIS_USER = 2;
  85         const RAW = 3;
  86
  87         /**
  88          * Load a page revision from a given revision ID number.
  89          * Returns null if no such revision can be found.
  90          *
  91          * $flags include:
  92          *      Revision::READ_LATEST  : Select the data from the master
  93          *      Revision::READ_LOCKING : Select & lock the data from the master
  94          *
  95          * @param int $id
  96          * @param int $flags (optional)
  97          * @return Revision|null
  98          */
  99         public static function newFromId( $id, $flags = 0 ) {
 100                 return self::newFromConds( [ 'rev_id' => intval( $id ) ], $flags );
 101         }
 102
 103         /**
 104          * Load either the current, or a specified, revision
 105          * that's attached to a given link target. If not attached
 106          * to that link target, will return null.
 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 LinkTarget $linkTarget
 113          * @param int $id (optional)
 114          * @param int $flags Bitfield (optional)
 115          * @return Revision|null
 116          */
 117         public static function newFromTitle( LinkTarget $linkTarget, $id = 0, $flags = 0 ) {
 118                 $conds = [
 119                         'page_namespace' => $linkTarget->getNamespace(),
 120                         'page_title' => $linkTarget->getDBkey()
 121                 ];
 122                 if ( $id ) {
 123                         // Use the specified ID
 124                         $conds['rev_id'] = $id;
 125                         return self::newFromConds( $conds, $flags );
 126                 } else {
 127                         // Use a join to get the latest revision
 128                         $conds[] = 'rev_id=page_latest';
 129                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 130                         return self::loadFromConds( $db, $conds, $flags );
 131                 }
 132         }
 133
 134         /**
 135          * Load either the current, or a specified, revision
 136          * that's attached to a given page ID.
 137          * Returns null if no such revision can be found.
 138          *
 139          * $flags include:
 140          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 141          *      Revision::READ_LOCKING : Select & lock the data from the master
 142          *
 143          * @param int $pageId
 144          * @param int $revId (optional)
 145          * @param int $flags Bitfield (optional)
 146          * @return Revision|null
 147          */
 148         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 149                 $conds = [ 'page_id' => $pageId ];
 150                 if ( $revId ) {
 151                         $conds['rev_id'] = $revId;
 152                         return self::newFromConds( $conds, $flags );
 153                 } else {
 154                         // Use a join to get the latest revision
 155                         $conds[] = 'rev_id = page_latest';
 156                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 157                         return self::loadFromConds( $db, $conds, $flags );
 158                 }
 159         }
 160
 161         /**
 162          * Make a fake revision object from an archive table row. This is queried
 163          * for permissions or even inserted (as in Special:Undelete)
 164          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 165          *
 166          * @param object $row
 167          * @param array $overrides
 168          *
 169          * @throws MWException
 170          * @return Revision
 171          */
 172         public static function newFromArchiveRow( $row, $overrides = [] ) {
 173                 global $wgContentHandlerUseDB;
 174
 175                 $attribs = $overrides + [
 176                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 177                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 178                         'comment'    => $row->ar_comment,
 179                         'user'       => $row->ar_user,
 180                         'user_text'  => $row->ar_user_text,
 181                         'timestamp'  => $row->ar_timestamp,
 182                         'minor_edit' => $row->ar_minor_edit,
 183                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 184                         'deleted'    => $row->ar_deleted,
 185                         'len'        => $row->ar_len,
 186                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 187                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 188                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 189                 ];
 190
 191                 if ( !$wgContentHandlerUseDB ) {
 192                         unset( $attribs['content_model'] );
 193                         unset( $attribs['content_format'] );
 194                 }
 195
 196                 if ( !isset( $attribs['title'] )
 197                         && isset( $row->ar_namespace )
 198                         && isset( $row->ar_title )
 199                 ) {
 200                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 201                 }
 202
 203                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 204                         // Pre-1.5 ar_text row
 205                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 206                         if ( $attribs['text'] === false ) {
 207                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 208                         }
 209                 }
 210                 return new self( $attribs );
 211         }
 212
 213         /**
 214          * @since 1.19
 215          *
 216          * @param object $row
 217          * @return Revision
 218          */
 219         public static function newFromRow( $row ) {
 220                 return new self( $row );
 221         }
 222
 223         /**
 224          * Load a page revision from a given revision ID number.
 225          * Returns null if no such revision can be found.
 226          *
 227          * @param IDatabase $db
 228          * @param int $id
 229          * @return Revision|null
 230          */
 231         public static function loadFromId( $db, $id ) {
 232                 return self::loadFromConds( $db, [ 'rev_id' => intval( $id ) ] );
 233         }
 234
 235         /**
 236          * Load either the current, or a specified, revision
 237          * that's attached to a given page. If not attached
 238          * to that page, will return null.
 239          *
 240          * @param IDatabase $db
 241          * @param int $pageid
 242          * @param int $id
 243          * @return Revision|null
 244          */
 245         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 246                 $conds = [ 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) ];
 247                 if ( $id ) {
 248                         $conds['rev_id'] = intval( $id );
 249                 } else {
 250                         $conds[] = 'rev_id=page_latest';
 251                 }
 252                 return self::loadFromConds( $db, $conds );
 253         }
 254
 255         /**
 256          * Load either the current, or a specified, revision
 257          * that's attached to a given page. If not attached
 258          * to that page, will return null.
 259          *
 260          * @param IDatabase $db
 261          * @param Title $title
 262          * @param int $id
 263          * @return Revision|null
 264          */
 265         public static function loadFromTitle( $db, $title, $id = 0 ) {
 266                 if ( $id ) {
 267                         $matchId = intval( $id );
 268                 } else {
 269                         $matchId = 'page_latest';
 270                 }
 271                 return self::loadFromConds( $db,
 272                         [
 273                                 "rev_id=$matchId",
 274                                 'page_namespace' => $title->getNamespace(),
 275                                 'page_title' => $title->getDBkey()
 276                         ]
 277                 );
 278         }
 279
 280         /**
 281          * Load the revision for the given title with the given timestamp.
 282          * WARNING: Timestamps may in some circumstances not be unique,
 283          * so this isn't the best key to use.
 284          *
 285          * @param IDatabase $db
 286          * @param Title $title
 287          * @param string $timestamp
 288          * @return Revision|null
 289          */
 290         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 291                 return self::loadFromConds( $db,
 292                         [
 293                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 294                                 'page_namespace' => $title->getNamespace(),
 295                                 'page_title' => $title->getDBkey()
 296                         ]
 297                 );
 298         }
 299
 300         /**
 301          * Given a set of conditions, fetch a revision
 302          *
 303          * This method is used then a revision ID is qualified and
 304          * will incorporate some basic slave/master fallback logic
 305          *
 306          * @param array $conditions
 307          * @param int $flags (optional)
 308          * @return Revision|null
 309          */
 310         private static function newFromConds( $conditions, $flags = 0 ) {
 311                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 312
 313                 $rev = self::loadFromConds( $db, $conditions, $flags );
 314                 // Make sure new pending/committed revision are visibile later on
 315                 // within web requests to certain avoid bugs like T93866 and T94407.
 316                 if ( !$rev
 317                         && !( $flags & self::READ_LATEST )
 318                         && wfGetLB()->getServerCount() > 1
 319                         && wfGetLB()->hasOrMadeRecentMasterChanges()
 320                 ) {
 321                         $flags = self::READ_LATEST;
 322                         $db = wfGetDB( DB_MASTER );
 323                         $rev = self::loadFromConds( $db, $conditions, $flags );
 324                 }
 325
 326                 if ( $rev ) {
 327                         $rev->mQueryFlags = $flags;
 328                 }
 329
 330                 return $rev;
 331         }
 332
 333         /**
 334          * Given a set of conditions, fetch a revision from
 335          * the given database connection.
 336          *
 337          * @param IDatabase $db
 338          * @param array $conditions
 339          * @param int $flags (optional)
 340          * @return Revision|null
 341          */
 342         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 343                 $res = self::fetchFromConds( $db, $conditions, $flags );
 344                 if ( $res ) {
 345                         $row = $res->fetchObject();
 346                         if ( $row ) {
 347                                 $ret = new Revision( $row );
 348                                 return $ret;
 349                         }
 350                 }
 351                 $ret = null;
 352                 return $ret;
 353         }
 354
 355         /**
 356          * Return a wrapper for a series of database rows to
 357          * fetch all of a given page's revisions in turn.
 358          * Each row can be fed to the constructor to get objects.
 359          *
 360          * @param Title $title
 361          * @return ResultWrapper
 362          */
 363         public static function fetchRevision( $title ) {
 364                 return self::fetchFromConds(
 365                         wfGetDB( DB_SLAVE ),
 366                         [
 367                                 'rev_id=page_latest',
 368                                 'page_namespace' => $title->getNamespace(),
 369                                 'page_title' => $title->getDBkey()
 370                         ]
 371                 );
 372         }
 373
 374         /**
 375          * Given a set of conditions, return a ResultWrapper
 376          * which will return matching database rows with the
 377          * fields necessary to build Revision objects.
 378          *
 379          * @param IDatabase $db
 380          * @param array $conditions
 381          * @param int $flags (optional)
 382          * @return ResultWrapper
 383          */
 384         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 385                 $fields = array_merge(
 386                         self::selectFields(),
 387                         self::selectPageFields(),
 388                         self::selectUserFields()
 389                 );
 390                 $options = [ 'LIMIT' => 1 ];
 391                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 392                         $options[] = 'FOR UPDATE';
 393                 }
 394                 return $db->select(
 395                         [ 'revision', 'page', 'user' ],
 396                         $fields,
 397                         $conditions,
 398                         __METHOD__,
 399                         $options,
 400                         [ 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() ]
 401                 );
 402         }
 403
 404         /**
 405          * Return the value of a select() JOIN conds array for the user table.
 406          * This will get user table rows for logged-in users.
 407          * @since 1.19
 408          * @return array
 409          */
 410         public static function userJoinCond() {
 411                 return [ 'LEFT JOIN', [ 'rev_user != 0', 'user_id = rev_user' ] ];
 412         }
 413
 414         /**
 415          * Return the value of a select() page conds array for the page table.
 416          * This will assure that the revision(s) are not orphaned from live pages.
 417          * @since 1.19
 418          * @return array
 419          */
 420         public static function pageJoinCond() {
 421                 return [ 'INNER JOIN', [ 'page_id = rev_page' ] ];
 422         }
 423
 424         /**
 425          * Return the list of revision fields that should be selected to create
 426          * a new revision.
 427          * @return array
 428          */
 429         public static function selectFields() {
 430                 global $wgContentHandlerUseDB;
 431
 432                 $fields = [
 433                         'rev_id',
 434                         'rev_page',
 435                         'rev_text_id',
 436                         'rev_timestamp',
 437                         'rev_comment',
 438                         'rev_user_text',
 439                         'rev_user',
 440                         'rev_minor_edit',
 441                         'rev_deleted',
 442                         'rev_len',
 443                         'rev_parent_id',
 444                         'rev_sha1',
 445                 ];
 446
 447                 if ( $wgContentHandlerUseDB ) {
 448                         $fields[] = 'rev_content_format';
 449                         $fields[] = 'rev_content_model';
 450                 }
 451
 452                 return $fields;
 453         }
 454
 455         /**
 456          * Return the list of revision fields that should be selected to create
 457          * a new revision from an archive row.
 458          * @return array
 459          */
 460         public static function selectArchiveFields() {
 461                 global $wgContentHandlerUseDB;
 462                 $fields = [
 463                         'ar_id',
 464                         'ar_page_id',
 465                         'ar_rev_id',
 466                         'ar_text',
 467                         'ar_text_id',
 468                         'ar_timestamp',
 469                         'ar_comment',
 470                         'ar_user_text',
 471                         'ar_user',
 472                         'ar_minor_edit',
 473                         'ar_deleted',
 474                         'ar_len',
 475                         'ar_parent_id',
 476                         'ar_sha1',
 477                 ];
 478
 479                 if ( $wgContentHandlerUseDB ) {
 480                         $fields[] = 'ar_content_format';
 481                         $fields[] = 'ar_content_model';
 482                 }
 483                 return $fields;
 484         }
 485
 486         /**
 487          * Return the list of text fields that should be selected to read the
 488          * revision text
 489          * @return array
 490          */
 491         public static function selectTextFields() {
 492                 return [
 493                         'old_text',
 494                         'old_flags'
 495                 ];
 496         }
 497
 498         /**
 499          * Return the list of page fields that should be selected from page table
 500          * @return array
 501          */
 502         public static function selectPageFields() {
 503                 return [
 504                         'page_namespace',
 505                         'page_title',
 506                         'page_id',
 507                         'page_latest',
 508                         'page_is_redirect',
 509                         'page_len',
 510                 ];
 511         }
 512
 513         /**
 514          * Return the list of user fields that should be selected from user table
 515          * @return array
 516          */
 517         public static function selectUserFields() {
 518                 return [ 'user_name' ];
 519         }
 520
 521         /**
 522          * Do a batched query to get the parent revision lengths
 523          * @param IDatabase $db
 524          * @param array $revIds
 525          * @return array
 526          */
 527         public static function getParentLengths( $db, array $revIds ) {
 528                 $revLens = [];
 529                 if ( !$revIds ) {
 530                         return $revLens; // empty
 531                 }
 532                 $res = $db->select( 'revision',
 533                         [ 'rev_id', 'rev_len' ],
 534                         [ 'rev_id' => $revIds ],
 535                         __METHOD__ );
 536                 foreach ( $res as $row ) {
 537                         $revLens[$row->rev_id] = $row->rev_len;
 538                 }
 539                 return $revLens;
 540         }
 541
 542         /**
 543          * Constructor
 544          *
 545          * @param object|array $row Either a database row or an array
 546          * @throws MWException
 547          * @access private
 548          */
 549         function __construct( $row ) {
 550                 if ( is_object( $row ) ) {
 551                         $this->mId = intval( $row->rev_id );
 552                         $this->mPage = intval( $row->rev_page );
 553                         $this->mTextId = intval( $row->rev_text_id );
 554                         $this->mComment = $row->rev_comment;
 555                         $this->mUser = intval( $row->rev_user );
 556                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 557                         $this->mTimestamp = $row->rev_timestamp;
 558                         $this->mDeleted = intval( $row->rev_deleted );
 559
 560                         if ( !isset( $row->rev_parent_id ) ) {
 561                                 $this->mParentId = null;
 562                         } else {
 563                                 $this->mParentId = intval( $row->rev_parent_id );
 564                         }
 565
 566                         if ( !isset( $row->rev_len ) ) {
 567                                 $this->mSize = null;
 568                         } else {
 569                                 $this->mSize = intval( $row->rev_len );
 570                         }
 571
 572                         if ( !isset( $row->rev_sha1 ) ) {
 573                                 $this->mSha1 = null;
 574                         } else {
 575                                 $this->mSha1 = $row->rev_sha1;
 576                         }
 577
 578                         if ( isset( $row->page_latest ) ) {
 579                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 580                                 $this->mTitle = Title::newFromRow( $row );
 581                         } else {
 582                                 $this->mCurrent = false;
 583                                 $this->mTitle = null;
 584                         }
 585
 586                         if ( !isset( $row->rev_content_model ) ) {
 587                                 $this->mContentModel = null; # determine on demand if needed
 588                         } else {
 589                                 $this->mContentModel = strval( $row->rev_content_model );
 590                         }
 591
 592                         if ( !isset( $row->rev_content_format ) ) {
 593                                 $this->mContentFormat = null; # determine on demand if needed
 594                         } else {
 595                                 $this->mContentFormat = strval( $row->rev_content_format );
 596                         }
 597
 598                         // Lazy extraction...
 599                         $this->mText = null;
 600                         if ( isset( $row->old_text ) ) {
 601                                 $this->mTextRow = $row;
 602                         } else {
 603                                 // 'text' table row entry will be lazy-loaded
 604                                 $this->mTextRow = null;
 605                         }
 606
 607                         // Use user_name for users and rev_user_text for IPs...
 608                         $this->mUserText = null; // lazy load if left null
 609                         if ( $this->mUser == 0 ) {
 610                                 $this->mUserText = $row->rev_user_text; // IP user
 611                         } elseif ( isset( $row->user_name ) ) {
 612                                 $this->mUserText = $row->user_name; // logged-in user
 613                         }
 614                         $this->mOrigUserText = $row->rev_user_text;
 615                 } elseif ( is_array( $row ) ) {
 616                         // Build a new revision to be saved...
 617                         global $wgUser; // ugh
 618
 619                         # if we have a content object, use it to set the model and type
 620                         if ( !empty( $row['content'] ) ) {
 621                                 // @todo when is that set? test with external store setup! check out insertOn() [dk]
 622                                 if ( !empty( $row['text_id'] ) ) {
 623                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 624                                                 "can't serialize content object" );
 625                                 }
 626
 627                                 $row['content_model'] = $row['content']->getModel();
 628                                 # note: mContentFormat is initializes later accordingly
 629                                 # note: content is serialized later in this method!
 630                                 # also set text to null?
 631                         }
 632
 633                         $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 634                         $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 635                         $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 636                         $this->mUserText = isset( $row['user_text'] )
 637                                 ? strval( $row['user_text'] ) : $wgUser->getName();
 638                         $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 639                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 640                         $this->mTimestamp = isset( $row['timestamp'] )
 641                                 ? strval( $row['timestamp'] ) : wfTimestampNow();
 642                         $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 643                         $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 644                         $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 645                         $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 646
 647                         $this->mContentModel = isset( $row['content_model'] )
 648                                 ? strval( $row['content_model'] ) : null;
 649                         $this->mContentFormat = isset( $row['content_format'] )
 650                                 ? strval( $row['content_format'] ) : null;
 651
 652                         // Enforce spacing trimming on supplied text
 653                         $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 654                         $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 655                         $this->mTextRow = null;
 656
 657                         $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 658
 659                         // if we have a Content object, override mText and mContentModel
 660                         if ( !empty( $row['content'] ) ) {
 661                                 if ( !( $row['content'] instanceof Content ) ) {
 662                                         throw new MWException( '`content` field must contain a Content object.' );
 663                                 }
 664
 665                                 $handler = $this->getContentHandler();
 666                                 $this->mContent = $row['content'];
 667
 668                                 $this->mContentModel = $this->mContent->getModel();
 669                                 $this->mContentHandler = null;
 670
 671                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 672                         } elseif ( $this->mText !== null ) {
 673                                 $handler = $this->getContentHandler();
 674                                 $this->mContent = $handler->unserializeContent( $this->mText );
 675                         }
 676
 677                         // If we have a Title object, make sure it is consistent with mPage.
 678                         if ( $this->mTitle && $this->mTitle->exists() ) {
 679                                 if ( $this->mPage === null ) {
 680                                         // if the page ID wasn't known, set it now
 681                                         $this->mPage = $this->mTitle->getArticleID();
 682                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 683                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 684                                         // but it seems worth mentioning it in the log.
 685                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 686                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 687                                 }
 688                         }
 689
 690                         $this->mCurrent = false;
 691
 692                         // If we still have no length, see it we have the text to figure it out
 693                         if ( !$this->mSize && $this->mContent !== null ) {
 694                                 $this->mSize = $this->mContent->getSize();
 695                         }
 696
 697                         // Same for sha1
 698                         if ( $this->mSha1 === null ) {
 699                                 $this->mSha1 = $this->mText === null ? null : self::base36Sha1( $this->mText );
 700                         }
 701
 702                         // force lazy init
 703                         $this->getContentModel();
 704                         $this->getContentFormat();
 705                 } else {
 706                         throw new MWException( 'Revision constructor passed invalid row format.' );
 707                 }
 708                 $this->mUnpatrolled = null;
 709         }
 710
 711         /**
 712          * Get revision ID
 713          *
 714          * @return int|null
 715          */
 716         public function getId() {
 717                 return $this->mId;
 718         }
 719
 720         /**
 721          * Set the revision ID
 722          *
 723          * This should only be used for proposed revisions that turn out to be null edits
 724          *
 725          * @since 1.19
 726          * @param int $id
 727          */
 728         public function setId( $id ) {
 729                 $this->mId = (int)$id;
 730         }
 731
 732         /**
 733          * Set the user ID/name
 734          *
 735          * This should only be used for proposed revisions that turn out to be null edits
 736          *
 737          * @since 1.28
 738          * @param integer $id User ID
 739          * @param string $name User name
 740          */
 741         public function setUserIdAndName( $id, $name ) {
 742                 $this->mUser = (int)$id;
 743                 $this->mUserText = $name;
 744                 $this->mOrigUserText = $name;
 745         }
 746
 747         /**
 748          * Get text row ID
 749          *
 750          * @return int|null
 751          */
 752         public function getTextId() {
 753                 return $this->mTextId;
 754         }
 755
 756         /**
 757          * Get parent revision ID (the original previous page revision)
 758          *
 759          * @return int|null
 760          */
 761         public function getParentId() {
 762                 return $this->mParentId;
 763         }
 764
 765         /**
 766          * Returns the length of the text in this revision, or null if unknown.
 767          *
 768          * @return int|null
 769          */
 770         public function getSize() {
 771                 return $this->mSize;
 772         }
 773
 774         /**
 775          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 776          *
 777          * @return string|null
 778          */
 779         public function getSha1() {
 780                 return $this->mSha1;
 781         }
 782
 783         /**
 784          * Returns the title of the page associated with this entry or null.
 785          *
 786          * Will do a query, when title is not set and id is given.
 787          *
 788          * @return Title|null
 789          */
 790         public function getTitle() {
 791                 if ( $this->mTitle !== null ) {
 792                         return $this->mTitle;
 793                 }
 794                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 795                 if ( $this->mId !== null ) {
 796                         $dbr = wfGetDB( DB_SLAVE );
 797                         $row = $dbr->selectRow(
 798                                 [ 'page', 'revision' ],
 799                                 self::selectPageFields(),
 800                                 [ 'page_id=rev_page',
 801                                         'rev_id' => $this->mId ],
 802                                 __METHOD__ );
 803                         if ( $row ) {
 804                                 $this->mTitle = Title::newFromRow( $row );
 805                         }
 806                 }
 807
 808                 if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 809                         $this->mTitle = Title::newFromID( $this->mPage );
 810                 }
 811
 812                 return $this->mTitle;
 813         }
 814
 815         /**
 816          * Set the title of the revision
 817          *
 818          * @param Title $title
 819          */
 820         public function setTitle( $title ) {
 821                 $this->mTitle = $title;
 822         }
 823
 824         /**
 825          * Get the page ID
 826          *
 827          * @return int|null
 828          */
 829         public function getPage() {
 830                 return $this->mPage;
 831         }
 832
 833         /**
 834          * Fetch revision's user id if it's available to the specified audience.
 835          * If the specified audience does not have access to it, zero will be
 836          * returned.
 837          *
 838          * @param int $audience One of:
 839          *   Revision::FOR_PUBLIC       to be displayed to all users
 840          *   Revision::FOR_THIS_USER    to be displayed to the given user
 841          *   Revision::RAW              get the ID regardless of permissions
 842          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 843          *   to the $audience parameter
 844          * @return int
 845          */
 846         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 847                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 848                         return 0;
 849                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 850                         return 0;
 851                 } else {
 852                         return $this->mUser;
 853                 }
 854         }
 855
 856         /**
 857          * Fetch revision's user id without regard for the current user's permissions
 858          *
 859          * @return string
 860          * @deprecated since 1.25, use getUser( Revision::RAW )
 861          */
 862         public function getRawUser() {
 863                 wfDeprecated( __METHOD__, '1.25' );
 864                 return $this->getUser( self::RAW );
 865         }
 866
 867         /**
 868          * Fetch revision's username if it's available to the specified audience.
 869          * If the specified audience does not have access to the username, an
 870          * empty string will be returned.
 871          *
 872          * @param int $audience One of:
 873          *   Revision::FOR_PUBLIC       to be displayed to all users
 874          *   Revision::FOR_THIS_USER    to be displayed to the given user
 875          *   Revision::RAW              get the text regardless of permissions
 876          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 877          *   to the $audience parameter
 878          * @return string
 879          */
 880         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 881                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 882                         return '';
 883                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 884                         return '';
 885                 } else {
 886                         if ( $this->mUserText === null ) {
 887                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 888                                 if ( $this->mUserText === false ) {
 889                                         # This shouldn't happen, but it can if the wiki was recovered
 890                                         # via importing revs and there is no user table entry yet.
 891                                         $this->mUserText = $this->mOrigUserText;
 892                                 }
 893                         }
 894                         return $this->mUserText;
 895                 }
 896         }
 897
 898         /**
 899          * Fetch revision's username without regard for view restrictions
 900          *
 901          * @return string
 902          * @deprecated since 1.25, use getUserText( Revision::RAW )
 903          */
 904         public function getRawUserText() {
 905                 wfDeprecated( __METHOD__, '1.25' );
 906                 return $this->getUserText( self::RAW );
 907         }
 908
 909         /**
 910          * Fetch revision comment if it's available to the specified audience.
 911          * If the specified audience does not have access to the comment, an
 912          * empty string will be returned.
 913          *
 914          * @param int $audience One of:
 915          *   Revision::FOR_PUBLIC       to be displayed to all users
 916          *   Revision::FOR_THIS_USER    to be displayed to the given user
 917          *   Revision::RAW              get the text regardless of permissions
 918          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 919          *   to the $audience parameter
 920          * @return string
 921          */
 922         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 923                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 924                         return '';
 925                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 926                         return '';
 927                 } else {
 928                         return $this->mComment;
 929                 }
 930         }
 931
 932         /**
 933          * Fetch revision comment without regard for the current user's permissions
 934          *
 935          * @return string
 936          * @deprecated since 1.25, use getComment( Revision::RAW )
 937          */
 938         public function getRawComment() {
 939                 wfDeprecated( __METHOD__, '1.25' );
 940                 return $this->getComment( self::RAW );
 941         }
 942
 943         /**
 944          * @return bool
 945          */
 946         public function isMinor() {
 947                 return (bool)$this->mMinorEdit;
 948         }
 949
 950         /**
 951          * @return int Rcid of the unpatrolled row, zero if there isn't one
 952          */
 953         public function isUnpatrolled() {
 954                 if ( $this->mUnpatrolled !== null ) {
 955                         return $this->mUnpatrolled;
 956                 }
 957                 $rc = $this->getRecentChange();
 958                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 959                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 960                 } else {
 961                         $this->mUnpatrolled = 0;
 962                 }
 963                 return $this->mUnpatrolled;
 964         }
 965
 966         /**
 967          * Get the RC object belonging to the current revision, if there's one
 968          *
 969          * @param int $flags (optional) $flags include:
 970          *      Revision::READ_LATEST  : Select the data from the master
 971          *
 972          * @since 1.22
 973          * @return RecentChange|null
 974          */
 975         public function getRecentChange( $flags = 0 ) {
 976                 $dbr = wfGetDB( DB_SLAVE );
 977
 978                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
 979
 980                 return RecentChange::newFromConds(
 981                         [
 982                                 'rc_user_text' => $this->getUserText( Revision::RAW ),
 983                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
 984                                 'rc_this_oldid' => $this->getId()
 985                         ],
 986                         __METHOD__,
 987                         $dbType
 988                 );
 989         }
 990
 991         /**
 992          * @param int $field One of DELETED_* bitfield constants
 993          *
 994          * @return bool
 995          */
 996         public function isDeleted( $field ) {
 997                 return ( $this->mDeleted & $field ) == $field;
 998         }
 999
1000         /**
1001          * Get the deletion bitfield of the revision
1002          *
1003          * @return int
1004          */
1005         public function getVisibility() {
1006                 return (int)$this->mDeleted;
1007         }
1008
1009         /**
1010          * Fetch revision text if it's available to the specified audience.
1011          * If the specified audience does not have the ability to view this
1012          * revision, an empty string will be returned.
1013          *
1014          * @param int $audience One of:
1015          *   Revision::FOR_PUBLIC       to be displayed to all users
1016          *   Revision::FOR_THIS_USER    to be displayed to the given user
1017          *   Revision::RAW              get the text regardless of permissions
1018          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1019          *   to the $audience parameter
1020          *
1021          * @deprecated since 1.21, use getContent() instead
1022          * @todo Replace usage in core
1023          * @return string
1024          */
1025         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
1026                 ContentHandler::deprecated( __METHOD__, '1.21' );
1027
1028                 $content = $this->getContent( $audience, $user );
1029                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
1030         }
1031
1032         /**
1033          * Fetch revision content if it's available to the specified audience.
1034          * If the specified audience does not have the ability to view this
1035          * revision, null will be returned.
1036          *
1037          * @param int $audience One of:
1038          *   Revision::FOR_PUBLIC       to be displayed to all users
1039          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1040          *   Revision::RAW              get the text regardless of permissions
1041          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1042          *   to the $audience parameter
1043          * @since 1.21
1044          * @return Content|null
1045          */
1046         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1047                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1048                         return null;
1049                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1050                         return null;
1051                 } else {
1052                         return $this->getContentInternal();
1053                 }
1054         }
1055
1056         /**
1057          * Fetch original serialized data without regard for view restrictions
1058          *
1059          * @since 1.21
1060          * @return string
1061          */
1062         public function getSerializedData() {
1063                 if ( $this->mText === null ) {
1064                         $this->mText = $this->loadText();
1065                 }
1066
1067                 return $this->mText;
1068         }
1069
1070         /**
1071          * Gets the content object for the revision (or null on failure).
1072          *
1073          * Note that for mutable Content objects, each call to this method will return a
1074          * fresh clone.
1075          *
1076          * @since 1.21
1077          * @return Content|null The Revision's content, or null on failure.
1078          */
1079         protected function getContentInternal() {
1080                 if ( $this->mContent === null ) {
1081                         // Revision is immutable. Load on demand:
1082                         if ( $this->mText === null ) {
1083                                 $this->mText = $this->loadText();
1084                         }
1085
1086                         if ( $this->mText !== null && $this->mText !== false ) {
1087                                 // Unserialize content
1088                                 $handler = $this->getContentHandler();
1089                                 $format = $this->getContentFormat();
1090
1091                                 $this->mContent = $handler->unserializeContent( $this->mText, $format );
1092                         }
1093                 }
1094
1095                 // NOTE: copy() will return $this for immutable content objects
1096                 return $this->mContent ? $this->mContent->copy() : null;
1097         }
1098
1099         /**
1100          * Returns the content model for this revision.
1101          *
1102          * If no content model was stored in the database, the default content model for the title is
1103          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1104          * is used as a last resort.
1105          *
1106          * @return string The content model id associated with this revision,
1107          *     see the CONTENT_MODEL_XXX constants.
1108          **/
1109         public function getContentModel() {
1110                 if ( !$this->mContentModel ) {
1111                         $title = $this->getTitle();
1112                         if ( $title ) {
1113                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1114                         } else {
1115                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1116                         }
1117
1118                         assert( !empty( $this->mContentModel ) );
1119                 }
1120
1121                 return $this->mContentModel;
1122         }
1123
1124         /**
1125          * Returns the content format for this revision.
1126          *
1127          * If no content format was stored in the database, the default format for this
1128          * revision's content model is returned.
1129          *
1130          * @return string The content format id associated with this revision,
1131          *     see the CONTENT_FORMAT_XXX constants.
1132          **/
1133         public function getContentFormat() {
1134                 if ( !$this->mContentFormat ) {
1135                         $handler = $this->getContentHandler();
1136                         $this->mContentFormat = $handler->getDefaultFormat();
1137
1138                         assert( !empty( $this->mContentFormat ) );
1139                 }
1140
1141                 return $this->mContentFormat;
1142         }
1143
1144         /**
1145          * Returns the content handler appropriate for this revision's content model.
1146          *
1147          * @throws MWException
1148          * @return ContentHandler
1149          */
1150         public function getContentHandler() {
1151                 if ( !$this->mContentHandler ) {
1152                         $model = $this->getContentModel();
1153                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1154
1155                         $format = $this->getContentFormat();
1156
1157                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1158                                 throw new MWException( "Oops, the content format $format is not supported for "
1159                                         . "this content model, $model" );
1160                         }
1161                 }
1162
1163                 return $this->mContentHandler;
1164         }
1165
1166         /**
1167          * @return string
1168          */
1169         public function getTimestamp() {
1170                 return wfTimestamp( TS_MW, $this->mTimestamp );
1171         }
1172
1173         /**
1174          * @return bool
1175          */
1176         public function isCurrent() {
1177                 return $this->mCurrent;
1178         }
1179
1180         /**
1181          * Get previous revision for this title
1182          *
1183          * @return Revision|null
1184          */
1185         public function getPrevious() {
1186                 if ( $this->getTitle() ) {
1187                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1188                         if ( $prev ) {
1189                                 return self::newFromTitle( $this->getTitle(), $prev );
1190                         }
1191                 }
1192                 return null;
1193         }
1194
1195         /**
1196          * Get next revision for this title
1197          *
1198          * @return Revision|null
1199          */
1200         public function getNext() {
1201                 if ( $this->getTitle() ) {
1202                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1203                         if ( $next ) {
1204                                 return self::newFromTitle( $this->getTitle(), $next );
1205                         }
1206                 }
1207                 return null;
1208         }
1209
1210         /**
1211          * Get previous revision Id for this page_id
1212          * This is used to populate rev_parent_id on save
1213          *
1214          * @param IDatabase $db
1215          * @return int
1216          */
1217         private function getPreviousRevisionId( $db ) {
1218                 if ( $this->mPage === null ) {
1219                         return 0;
1220                 }
1221                 # Use page_latest if ID is not given
1222                 if ( !$this->mId ) {
1223                         $prevId = $db->selectField( 'page', 'page_latest',
1224                                 [ 'page_id' => $this->mPage ],
1225                                 __METHOD__ );
1226                 } else {
1227                         $prevId = $db->selectField( 'revision', 'rev_id',
1228                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1229                                 __METHOD__,
1230                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1231                 }
1232                 return intval( $prevId );
1233         }
1234
1235         /**
1236          * Get revision text associated with an old or archive row
1237          * $row is usually an object from wfFetchRow(), both the flags and the text
1238          * field must be included.
1239          *
1240          * @param stdClass $row The text data
1241          * @param string $prefix Table prefix (default 'old_')
1242          * @param string|bool $wiki The name of the wiki to load the revision text from
1243          *   (same as the the wiki $row was loaded from) or false to indicate the local
1244          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1245          *   identifier as understood by the LoadBalancer class.
1246          * @return string Text the text requested or false on failure
1247          */
1248         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1249
1250                 # Get data
1251                 $textField = $prefix . 'text';
1252                 $flagsField = $prefix . 'flags';
1253
1254                 if ( isset( $row->$flagsField ) ) {
1255                         $flags = explode( ',', $row->$flagsField );
1256                 } else {
1257                         $flags = [];
1258                 }
1259
1260                 if ( isset( $row->$textField ) ) {
1261                         $text = $row->$textField;
1262                 } else {
1263                         return false;
1264                 }
1265
1266                 # Use external methods for external objects, text in table is URL-only then
1267                 if ( in_array( 'external', $flags ) ) {
1268                         $url = $text;
1269                         $parts = explode( '://', $url, 2 );
1270                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1271                                 return false;
1272                         }
1273                         $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1274                 }
1275
1276                 // If the text was fetched without an error, convert it
1277                 if ( $text !== false ) {
1278                         $text = self::decompressRevisionText( $text, $flags );
1279                 }
1280                 return $text;
1281         }
1282
1283         /**
1284          * If $wgCompressRevisions is enabled, we will compress data.
1285          * The input string is modified in place.
1286          * Return value is the flags field: contains 'gzip' if the
1287          * data is compressed, and 'utf-8' if we're saving in UTF-8
1288          * mode.
1289          *
1290          * @param mixed $text Reference to a text
1291          * @return string
1292          */
1293         public static function compressRevisionText( &$text ) {
1294                 global $wgCompressRevisions;
1295                 $flags = [];
1296
1297                 # Revisions not marked this way will be converted
1298                 # on load if $wgLegacyCharset is set in the future.
1299                 $flags[] = 'utf-8';
1300
1301                 if ( $wgCompressRevisions ) {
1302                         if ( function_exists( 'gzdeflate' ) ) {
1303                                 $deflated = gzdeflate( $text );
1304
1305                                 if ( $deflated === false ) {
1306                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1307                                 } else {
1308                                         $text = $deflated;
1309                                         $flags[] = 'gzip';
1310                                 }
1311                         } else {
1312                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1313                         }
1314                 }
1315                 return implode( ',', $flags );
1316         }
1317
1318         /**
1319          * Re-converts revision text according to it's flags.
1320          *
1321          * @param mixed $text Reference to a text
1322          * @param array $flags Compression flags
1323          * @return string|bool Decompressed text, or false on failure
1324          */
1325         public static function decompressRevisionText( $text, $flags ) {
1326                 if ( in_array( 'gzip', $flags ) ) {
1327                         # Deal with optional compression of archived pages.
1328                         # This can be done periodically via maintenance/compressOld.php, and
1329                         # as pages are saved if $wgCompressRevisions is set.
1330                         $text = gzinflate( $text );
1331
1332                         if ( $text === false ) {
1333                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1334                                 return false;
1335                         }
1336                 }
1337
1338                 if ( in_array( 'object', $flags ) ) {
1339                         # Generic compressed storage
1340                         $obj = unserialize( $text );
1341                         if ( !is_object( $obj ) ) {
1342                                 // Invalid object
1343                                 return false;
1344                         }
1345                         $text = $obj->getText();
1346                 }
1347
1348                 global $wgLegacyEncoding;
1349                 if ( $text !== false && $wgLegacyEncoding
1350                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1351                 ) {
1352                         # Old revisions kept around in a legacy encoding?
1353                         # Upconvert on demand.
1354                         # ("utf8" checked for compatibility with some broken
1355                         #  conversion scripts 2008-12-30)
1356                         global $wgContLang;
1357                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1358                 }
1359
1360                 return $text;
1361         }
1362
1363         /**
1364          * Insert a new revision into the database, returning the new revision ID
1365          * number on success and dies horribly on failure.
1366          *
1367          * @param IDatabase $dbw (master connection)
1368          * @throws MWException
1369          * @return int
1370          */
1371         public function insertOn( $dbw ) {
1372                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1373
1374                 // Not allowed to have rev_page equal to 0, false, etc.
1375                 if ( !$this->mPage ) {
1376                         $title = $this->getTitle();
1377                         if ( $title instanceof Title ) {
1378                                 $titleText = ' for page ' . $title->getPrefixedText();
1379                         } else {
1380                                 $titleText = '';
1381                         }
1382                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1383                 }
1384
1385                 $this->checkContentModel();
1386
1387                 $data = $this->mText;
1388                 $flags = self::compressRevisionText( $data );
1389
1390                 # Write to external storage if required
1391                 if ( $wgDefaultExternalStore ) {
1392                         // Store and get the URL
1393                         $data = ExternalStore::insertToDefault( $data );
1394                         if ( !$data ) {
1395                                 throw new MWException( "Unable to store text to external storage" );
1396                         }
1397                         if ( $flags ) {
1398                                 $flags .= ',';
1399                         }
1400                         $flags .= 'external';
1401                 }
1402
1403                 # Record the text (or external storage URL) to the text table
1404                 if ( $this->mTextId === null ) {
1405                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1406                         $dbw->insert( 'text',
1407                                 [
1408                                         'old_id' => $old_id,
1409                                         'old_text' => $data,
1410                                         'old_flags' => $flags,
1411                                 ], __METHOD__
1412                         );
1413                         $this->mTextId = $dbw->insertId();
1414                 }
1415
1416                 if ( $this->mComment === null ) {
1417                         $this->mComment = "";
1418                 }
1419
1420                 # Record the edit in revisions
1421                 $rev_id = $this->mId !== null
1422                         ? $this->mId
1423                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1424                 $row = [
1425                         'rev_id'         => $rev_id,
1426                         'rev_page'       => $this->mPage,
1427                         'rev_text_id'    => $this->mTextId,
1428                         'rev_comment'    => $this->mComment,
1429                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1430                         'rev_user'       => $this->mUser,
1431                         'rev_user_text'  => $this->mUserText,
1432                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1433                         'rev_deleted'    => $this->mDeleted,
1434                         'rev_len'        => $this->mSize,
1435                         'rev_parent_id'  => $this->mParentId === null
1436                                 ? $this->getPreviousRevisionId( $dbw )
1437                                 : $this->mParentId,
1438                         'rev_sha1'       => $this->mSha1 === null
1439                                 ? Revision::base36Sha1( $this->mText )
1440                                 : $this->mSha1,
1441                 ];
1442
1443                 if ( $wgContentHandlerUseDB ) {
1444                         // NOTE: Store null for the default model and format, to save space.
1445                         // XXX: Makes the DB sensitive to changed defaults.
1446                         // Make this behavior optional? Only in miser mode?
1447
1448                         $model = $this->getContentModel();
1449                         $format = $this->getContentFormat();
1450
1451                         $title = $this->getTitle();
1452
1453                         if ( $title === null ) {
1454                                 throw new MWException( "Insufficient information to determine the title of the "
1455                                         . "revision's page!" );
1456                         }
1457
1458                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1459                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1460
1461                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1462                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1463                 }
1464
1465                 $dbw->insert( 'revision', $row, __METHOD__ );
1466
1467                 $this->mId = $rev_id !== null ? $rev_id : $dbw->insertId();
1468
1469                 // Assertion to try to catch T92046
1470                 if ( (int)$this->mId === 0 ) {
1471                         throw new UnexpectedValueException(
1472                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1473                                         var_export( $row, 1 )
1474                         );
1475                 }
1476
1477                 Hooks::run( 'RevisionInsertComplete', [ &$this, $data, $flags ] );
1478
1479                 return $this->mId;
1480         }
1481
1482         protected function checkContentModel() {
1483                 global $wgContentHandlerUseDB;
1484
1485                 // Note: may return null for revisions that have not yet been inserted
1486                 $title = $this->getTitle();
1487
1488                 $model = $this->getContentModel();
1489                 $format = $this->getContentFormat();
1490                 $handler = $this->getContentHandler();
1491
1492                 if ( !$handler->isSupportedFormat( $format ) ) {
1493                         $t = $title->getPrefixedDBkey();
1494
1495                         throw new MWException( "Can't use format $format with content model $model on $t" );
1496                 }
1497
1498                 if ( !$wgContentHandlerUseDB && $title ) {
1499                         // if $wgContentHandlerUseDB is not set,
1500                         // all revisions must use the default content model and format.
1501
1502                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1503                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1504                         $defaultFormat = $defaultHandler->getDefaultFormat();
1505
1506                         if ( $this->getContentModel() != $defaultModel ) {
1507                                 $t = $title->getPrefixedDBkey();
1508
1509                                 throw new MWException( "Can't save non-default content model with "
1510                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1511                                         . "default for $t is $defaultModel" );
1512                         }
1513
1514                         if ( $this->getContentFormat() != $defaultFormat ) {
1515                                 $t = $title->getPrefixedDBkey();
1516
1517                                 throw new MWException( "Can't use non-default content format with "
1518                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1519                                         . "default for $t is $defaultFormat" );
1520                         }
1521                 }
1522
1523                 $content = $this->getContent( Revision::RAW );
1524                 $prefixedDBkey = $title->getPrefixedDBkey();
1525                 $revId = $this->mId;
1526
1527                 if ( !$content ) {
1528                         throw new MWException(
1529                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1530                         );
1531                 }
1532                 if ( !$content->isValid() ) {
1533                         throw new MWException(
1534                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1535                         );
1536                 }
1537         }
1538
1539         /**
1540          * Get the base 36 SHA-1 value for a string of text
1541          * @param string $text
1542          * @return string
1543          */
1544         public static function base36Sha1( $text ) {
1545                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1546         }
1547
1548         /**
1549          * Lazy-load the revision's text.
1550          * Currently hardcoded to the 'text' table storage engine.
1551          *
1552          * @return string|bool The revision's text, or false on failure
1553          */
1554         protected function loadText() {
1555                 // Caching may be beneficial for massive use of external storage
1556                 global $wgRevisionCacheExpiry;
1557                 static $processCache = null;
1558
1559                 if ( !$processCache ) {
1560                         $processCache = new MapCacheLRU( 10 );
1561                 }
1562
1563                 $cache = ObjectCache::getMainWANInstance();
1564                 $textId = $this->getTextId();
1565                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1566
1567                 if ( $wgRevisionCacheExpiry ) {
1568                         if ( $processCache->has( $key ) ) {
1569                                 return $processCache->get( $key );
1570                         }
1571                         $text = $cache->get( $key );
1572                         if ( is_string( $text ) ) {
1573                                 $processCache->set( $key, $text );
1574                                 return $text;
1575                         }
1576                 }
1577
1578                 // If we kept data for lazy extraction, use it now...
1579                 if ( $this->mTextRow !== null ) {
1580                         $row = $this->mTextRow;
1581                         $this->mTextRow = null;
1582                 } else {
1583                         $row = null;
1584                 }
1585
1586                 if ( !$row ) {
1587                         // Text data is immutable; check slaves first.
1588                         $dbr = wfGetDB( DB_SLAVE );
1589                         $row = $dbr->selectRow( 'text',
1590                                 [ 'old_text', 'old_flags' ],
1591                                 [ 'old_id' => $textId ],
1592                                 __METHOD__ );
1593                 }
1594
1595                 // Fallback to the master in case of slave lag. Also use FOR UPDATE if it was
1596                 // used to fetch this revision to avoid missing the row due to REPEATABLE-READ.
1597                 $forUpdate = ( $this->mQueryFlags & self::READ_LOCKING == self::READ_LOCKING );
1598                 if ( !$row && ( $forUpdate || wfGetLB()->getServerCount() > 1 ) ) {
1599                         $dbw = wfGetDB( DB_MASTER );
1600                         $row = $dbw->selectRow( 'text',
1601                                 [ 'old_text', 'old_flags' ],
1602                                 [ 'old_id' => $textId ],
1603                                 __METHOD__,
1604                                 $forUpdate ? [ 'FOR UPDATE' ] : [] );
1605                 }
1606
1607                 if ( !$row ) {
1608                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1609                 }
1610
1611                 $text = self::getRevisionText( $row );
1612                 if ( $row && $text === false ) {
1613                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1614                 }
1615
1616                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1617                 if ( $wgRevisionCacheExpiry && $text !== false ) {
1618                         $processCache->set( $key, $text );
1619                         $cache->set( $key, $text, $wgRevisionCacheExpiry );
1620                 }
1621
1622                 return $text;
1623         }
1624
1625         /**
1626          * Create a new null-revision for insertion into a page's
1627          * history. This will not re-save the text, but simply refer
1628          * to the text from the previous version.
1629          *
1630          * Such revisions can for instance identify page rename
1631          * operations and other such meta-modifications.
1632          *
1633          * @param IDatabase $dbw
1634          * @param int $pageId ID number of the page to read from
1635          * @param string $summary Revision's summary
1636          * @param bool $minor Whether the revision should be considered as minor
1637          * @param User|null $user User object to use or null for $wgUser
1638          * @return Revision|null Revision or null on error
1639          */
1640         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1641                 global $wgContentHandlerUseDB, $wgContLang;
1642
1643                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1644                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1645
1646                 if ( $wgContentHandlerUseDB ) {
1647                         $fields[] = 'rev_content_model';
1648                         $fields[] = 'rev_content_format';
1649                 }
1650
1651                 $current = $dbw->selectRow(
1652                         [ 'page', 'revision' ],
1653                         $fields,
1654                         [
1655                                 'page_id' => $pageId,
1656                                 'page_latest=rev_id',
1657                         ],
1658                         __METHOD__,
1659                         [ 'FOR UPDATE' ] // T51581
1660                 );
1661
1662                 if ( $current ) {
1663                         if ( !$user ) {
1664                                 global $wgUser;
1665                                 $user = $wgUser;
1666                         }
1667
1668                         // Truncate for whole multibyte characters
1669                         $summary = $wgContLang->truncate( $summary, 255 );
1670
1671                         $row = [
1672                                 'page'       => $pageId,
1673                                 'user_text'  => $user->getName(),
1674                                 'user'       => $user->getId(),
1675                                 'comment'    => $summary,
1676                                 'minor_edit' => $minor,
1677                                 'text_id'    => $current->rev_text_id,
1678                                 'parent_id'  => $current->page_latest,
1679                                 'len'        => $current->rev_len,
1680                                 'sha1'       => $current->rev_sha1
1681                         ];
1682
1683                         if ( $wgContentHandlerUseDB ) {
1684                                 $row['content_model'] = $current->rev_content_model;
1685                                 $row['content_format'] = $current->rev_content_format;
1686                         }
1687
1688                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1689
1690                         $revision = new Revision( $row );
1691                 } else {
1692                         $revision = null;
1693                 }
1694
1695                 return $revision;
1696         }
1697
1698         /**
1699          * Determine if the current user is allowed to view a particular
1700          * field of this revision, if it's marked as deleted.
1701          *
1702          * @param int $field One of self::DELETED_TEXT,
1703          *                              self::DELETED_COMMENT,
1704          *                              self::DELETED_USER
1705          * @param User|null $user User object to check, or null to use $wgUser
1706          * @return bool
1707          */
1708         public function userCan( $field, User $user = null ) {
1709                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1710         }
1711
1712         /**
1713          * Determine if the current user is allowed to view a particular
1714          * field of this revision, if it's marked as deleted. This is used
1715          * by various classes to avoid duplication.
1716          *
1717          * @param int $bitfield Current field
1718          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1719          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1720          *                               self::DELETED_USER = File::DELETED_USER
1721          * @param User|null $user User object to check, or null to use $wgUser
1722          * @param Title|null $title A Title object to check for per-page restrictions on,
1723          *                          instead of just plain userrights
1724          * @return bool
1725          */
1726         public static function userCanBitfield( $bitfield, $field, User $user = null,
1727                 Title $title = null
1728         ) {
1729                 if ( $bitfield & $field ) { // aspect is deleted
1730                         if ( $user === null ) {
1731                                 global $wgUser;
1732                                 $user = $wgUser;
1733                         }
1734                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1735                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1736                         } elseif ( $field & self::DELETED_TEXT ) {
1737                                 $permissions = [ 'deletedtext' ];
1738                         } else {
1739                                 $permissions = [ 'deletedhistory' ];
1740                         }
1741                         $permissionlist = implode( ', ', $permissions );
1742                         if ( $title === null ) {
1743                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1744                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1745                         } else {
1746                                 $text = $title->getPrefixedText();
1747                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1748                                 foreach ( $permissions as $perm ) {
1749                                         if ( $title->userCan( $perm, $user ) ) {
1750                                                 return true;
1751                                         }
1752                                 }
1753                                 return false;
1754                         }
1755                 } else {
1756                         return true;
1757                 }
1758         }
1759
1760         /**
1761          * Get rev_timestamp from rev_id, without loading the rest of the row
1762          *
1763          * @param Title $title
1764          * @param int $id
1765          * @return string|bool False if not found
1766          */
1767         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1768                 $db = ( $flags & self::READ_LATEST )
1769                         ? wfGetDB( DB_MASTER )
1770                         : wfGetDB( DB_SLAVE );
1771                 // Casting fix for databases that can't take '' for rev_id
1772                 if ( $id == '' ) {
1773                         $id = 0;
1774                 }
1775                 $conds = [ 'rev_id' => $id ];
1776                 $conds['rev_page'] = $title->getArticleID();
1777                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1778
1779                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
1780         }
1781
1782         /**
1783          * Get count of revisions per page...not very efficient
1784          *
1785          * @param IDatabase $db
1786          * @param int $id Page id
1787          * @return int
1788          */
1789         static function countByPageId( $db, $id ) {
1790                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
1791                         [ 'rev_page' => $id ], __METHOD__ );
1792                 if ( $row ) {
1793                         return $row->revCount;
1794                 }
1795                 return 0;
1796         }
1797
1798         /**
1799          * Get count of revisions per page...not very efficient
1800          *
1801          * @param IDatabase $db
1802          * @param Title $title
1803          * @return int
1804          */
1805         static function countByTitle( $db, $title ) {
1806                 $id = $title->getArticleID();
1807                 if ( $id ) {
1808                         return self::countByPageId( $db, $id );
1809                 }
1810                 return 0;
1811         }
1812
1813         /**
1814          * Check if no edits were made by other users since
1815          * the time a user started editing the page. Limit to
1816          * 50 revisions for the sake of performance.
1817          *
1818          * @since 1.20
1819          * @deprecated since 1.24
1820          *
1821          * @param IDatabase|int $db The Database to perform the check on. May be given as a
1822          *        Database object or a database identifier usable with wfGetDB.
1823          * @param int $pageId The ID of the page in question
1824          * @param int $userId The ID of the user in question
1825          * @param string $since Look at edits since this time
1826          *
1827          * @return bool True if the given user was the only one to edit since the given timestamp
1828          */
1829         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1830                 if ( !$userId ) {
1831                         return false;
1832                 }
1833
1834                 if ( is_int( $db ) ) {
1835                         $db = wfGetDB( $db );
1836                 }
1837
1838                 $res = $db->select( 'revision',
1839                         'rev_user',
1840                         [
1841                                 'rev_page' => $pageId,
1842                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1843                         ],
1844                         __METHOD__,
1845                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
1846                 foreach ( $res as $row ) {
1847                         if ( $row->rev_user != $userId ) {
1848                                 return false;
1849                         }
1850                 }
1851                 return true;
1852         }
1853 }