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          * @since 1.19
 724          * @param int $id
 725          */
 726         public function setId( $id ) {
 727                 $this->mId = $id;
 728         }
 729
 730         /**
 731          * Get text row ID
 732          *
 733          * @return int|null
 734          */
 735         public function getTextId() {
 736                 return $this->mTextId;
 737         }
 738
 739         /**
 740          * Get parent revision ID (the original previous page revision)
 741          *
 742          * @return int|null
 743          */
 744         public function getParentId() {
 745                 return $this->mParentId;
 746         }
 747
 748         /**
 749          * Returns the length of the text in this revision, or null if unknown.
 750          *
 751          * @return int|null
 752          */
 753         public function getSize() {
 754                 return $this->mSize;
 755         }
 756
 757         /**
 758          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 759          *
 760          * @return string|null
 761          */
 762         public function getSha1() {
 763                 return $this->mSha1;
 764         }
 765
 766         /**
 767          * Returns the title of the page associated with this entry or null.
 768          *
 769          * Will do a query, when title is not set and id is given.
 770          *
 771          * @return Title|null
 772          */
 773         public function getTitle() {
 774                 if ( $this->mTitle !== null ) {
 775                         return $this->mTitle;
 776                 }
 777                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 778                 if ( $this->mId !== null ) {
 779                         $dbr = wfGetDB( DB_SLAVE );
 780                         $row = $dbr->selectRow(
 781                                 [ 'page', 'revision' ],
 782                                 self::selectPageFields(),
 783                                 [ 'page_id=rev_page',
 784                                         'rev_id' => $this->mId ],
 785                                 __METHOD__ );
 786                         if ( $row ) {
 787                                 $this->mTitle = Title::newFromRow( $row );
 788                         }
 789                 }
 790
 791                 if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 792                         $this->mTitle = Title::newFromID( $this->mPage );
 793                 }
 794
 795                 return $this->mTitle;
 796         }
 797
 798         /**
 799          * Set the title of the revision
 800          *
 801          * @param Title $title
 802          */
 803         public function setTitle( $title ) {
 804                 $this->mTitle = $title;
 805         }
 806
 807         /**
 808          * Get the page ID
 809          *
 810          * @return int|null
 811          */
 812         public function getPage() {
 813                 return $this->mPage;
 814         }
 815
 816         /**
 817          * Fetch revision's user id if it's available to the specified audience.
 818          * If the specified audience does not have access to it, zero will be
 819          * returned.
 820          *
 821          * @param int $audience One of:
 822          *   Revision::FOR_PUBLIC       to be displayed to all users
 823          *   Revision::FOR_THIS_USER    to be displayed to the given user
 824          *   Revision::RAW              get the ID regardless of permissions
 825          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 826          *   to the $audience parameter
 827          * @return int
 828          */
 829         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 830                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 831                         return 0;
 832                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 833                         return 0;
 834                 } else {
 835                         return $this->mUser;
 836                 }
 837         }
 838
 839         /**
 840          * Fetch revision's user id without regard for the current user's permissions
 841          *
 842          * @return string
 843          * @deprecated since 1.25, use getUser( Revision::RAW )
 844          */
 845         public function getRawUser() {
 846                 wfDeprecated( __METHOD__, '1.25' );
 847                 return $this->getUser( self::RAW );
 848         }
 849
 850         /**
 851          * Fetch revision's username if it's available to the specified audience.
 852          * If the specified audience does not have access to the username, an
 853          * empty string will be returned.
 854          *
 855          * @param int $audience One of:
 856          *   Revision::FOR_PUBLIC       to be displayed to all users
 857          *   Revision::FOR_THIS_USER    to be displayed to the given user
 858          *   Revision::RAW              get the text regardless of permissions
 859          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 860          *   to the $audience parameter
 861          * @return string
 862          */
 863         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 864                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 865                         return '';
 866                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 867                         return '';
 868                 } else {
 869                         if ( $this->mUserText === null ) {
 870                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 871                                 if ( $this->mUserText === false ) {
 872                                         # This shouldn't happen, but it can if the wiki was recovered
 873                                         # via importing revs and there is no user table entry yet.
 874                                         $this->mUserText = $this->mOrigUserText;
 875                                 }
 876                         }
 877                         return $this->mUserText;
 878                 }
 879         }
 880
 881         /**
 882          * Fetch revision's username without regard for view restrictions
 883          *
 884          * @return string
 885          * @deprecated since 1.25, use getUserText( Revision::RAW )
 886          */
 887         public function getRawUserText() {
 888                 wfDeprecated( __METHOD__, '1.25' );
 889                 return $this->getUserText( self::RAW );
 890         }
 891
 892         /**
 893          * Fetch revision comment if it's available to the specified audience.
 894          * If the specified audience does not have access to the comment, an
 895          * empty string will be returned.
 896          *
 897          * @param int $audience One of:
 898          *   Revision::FOR_PUBLIC       to be displayed to all users
 899          *   Revision::FOR_THIS_USER    to be displayed to the given user
 900          *   Revision::RAW              get the text regardless of permissions
 901          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 902          *   to the $audience parameter
 903          * @return string
 904          */
 905         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 906                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 907                         return '';
 908                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 909                         return '';
 910                 } else {
 911                         return $this->mComment;
 912                 }
 913         }
 914
 915         /**
 916          * Fetch revision comment without regard for the current user's permissions
 917          *
 918          * @return string
 919          * @deprecated since 1.25, use getComment( Revision::RAW )
 920          */
 921         public function getRawComment() {
 922                 wfDeprecated( __METHOD__, '1.25' );
 923                 return $this->getComment( self::RAW );
 924         }
 925
 926         /**
 927          * @return bool
 928          */
 929         public function isMinor() {
 930                 return (bool)$this->mMinorEdit;
 931         }
 932
 933         /**
 934          * @return int Rcid of the unpatrolled row, zero if there isn't one
 935          */
 936         public function isUnpatrolled() {
 937                 if ( $this->mUnpatrolled !== null ) {
 938                         return $this->mUnpatrolled;
 939                 }
 940                 $rc = $this->getRecentChange();
 941                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 942                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 943                 } else {
 944                         $this->mUnpatrolled = 0;
 945                 }
 946                 return $this->mUnpatrolled;
 947         }
 948
 949         /**
 950          * Get the RC object belonging to the current revision, if there's one
 951          *
 952          * @param int $flags (optional) $flags include:
 953          *      Revision::READ_LATEST  : Select the data from the master
 954          *
 955          * @since 1.22
 956          * @return RecentChange|null
 957          */
 958         public function getRecentChange( $flags = 0 ) {
 959                 $dbr = wfGetDB( DB_SLAVE );
 960
 961                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
 962
 963                 return RecentChange::newFromConds(
 964                         [
 965                                 'rc_user_text' => $this->getUserText( Revision::RAW ),
 966                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
 967                                 'rc_this_oldid' => $this->getId()
 968                         ],
 969                         __METHOD__,
 970                         $dbType
 971                 );
 972         }
 973
 974         /**
 975          * @param int $field One of DELETED_* bitfield constants
 976          *
 977          * @return bool
 978          */
 979         public function isDeleted( $field ) {
 980                 return ( $this->mDeleted & $field ) == $field;
 981         }
 982
 983         /**
 984          * Get the deletion bitfield of the revision
 985          *
 986          * @return int
 987          */
 988         public function getVisibility() {
 989                 return (int)$this->mDeleted;
 990         }
 991
 992         /**
 993          * Fetch revision text if it's available to the specified audience.
 994          * If the specified audience does not have the ability to view this
 995          * revision, an empty string will be returned.
 996          *
 997          * @param int $audience One of:
 998          *   Revision::FOR_PUBLIC       to be displayed to all users
 999          *   Revision::FOR_THIS_USER    to be displayed to the given user
1000          *   Revision::RAW              get the text regardless of permissions
1001          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1002          *   to the $audience parameter
1003          *
1004          * @deprecated since 1.21, use getContent() instead
1005          * @todo Replace usage in core
1006          * @return string
1007          */
1008         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
1009                 ContentHandler::deprecated( __METHOD__, '1.21' );
1010
1011                 $content = $this->getContent( $audience, $user );
1012                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
1013         }
1014
1015         /**
1016          * Fetch revision content if it's available to the specified audience.
1017          * If the specified audience does not have the ability to view this
1018          * revision, null will be returned.
1019          *
1020          * @param int $audience One of:
1021          *   Revision::FOR_PUBLIC       to be displayed to all users
1022          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1023          *   Revision::RAW              get the text regardless of permissions
1024          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1025          *   to the $audience parameter
1026          * @since 1.21
1027          * @return Content|null
1028          */
1029         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1030                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1031                         return null;
1032                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1033                         return null;
1034                 } else {
1035                         return $this->getContentInternal();
1036                 }
1037         }
1038
1039         /**
1040          * Fetch original serialized data without regard for view restrictions
1041          *
1042          * @since 1.21
1043          * @return string
1044          */
1045         public function getSerializedData() {
1046                 if ( $this->mText === null ) {
1047                         $this->mText = $this->loadText();
1048                 }
1049
1050                 return $this->mText;
1051         }
1052
1053         /**
1054          * Gets the content object for the revision (or null on failure).
1055          *
1056          * Note that for mutable Content objects, each call to this method will return a
1057          * fresh clone.
1058          *
1059          * @since 1.21
1060          * @return Content|null The Revision's content, or null on failure.
1061          */
1062         protected function getContentInternal() {
1063                 if ( $this->mContent === null ) {
1064                         // Revision is immutable. Load on demand:
1065                         if ( $this->mText === null ) {
1066                                 $this->mText = $this->loadText();
1067                         }
1068
1069                         if ( $this->mText !== null && $this->mText !== false ) {
1070                                 // Unserialize content
1071                                 $handler = $this->getContentHandler();
1072                                 $format = $this->getContentFormat();
1073
1074                                 $this->mContent = $handler->unserializeContent( $this->mText, $format );
1075                         }
1076                 }
1077
1078                 // NOTE: copy() will return $this for immutable content objects
1079                 return $this->mContent ? $this->mContent->copy() : null;
1080         }
1081
1082         /**
1083          * Returns the content model for this revision.
1084          *
1085          * If no content model was stored in the database, the default content model for the title is
1086          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1087          * is used as a last resort.
1088          *
1089          * @return string The content model id associated with this revision,
1090          *     see the CONTENT_MODEL_XXX constants.
1091          **/
1092         public function getContentModel() {
1093                 if ( !$this->mContentModel ) {
1094                         $title = $this->getTitle();
1095                         if ( $title ) {
1096                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1097                         } else {
1098                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1099                         }
1100
1101                         assert( !empty( $this->mContentModel ) );
1102                 }
1103
1104                 return $this->mContentModel;
1105         }
1106
1107         /**
1108          * Returns the content format for this revision.
1109          *
1110          * If no content format was stored in the database, the default format for this
1111          * revision's content model is returned.
1112          *
1113          * @return string The content format id associated with this revision,
1114          *     see the CONTENT_FORMAT_XXX constants.
1115          **/
1116         public function getContentFormat() {
1117                 if ( !$this->mContentFormat ) {
1118                         $handler = $this->getContentHandler();
1119                         $this->mContentFormat = $handler->getDefaultFormat();
1120
1121                         assert( !empty( $this->mContentFormat ) );
1122                 }
1123
1124                 return $this->mContentFormat;
1125         }
1126
1127         /**
1128          * Returns the content handler appropriate for this revision's content model.
1129          *
1130          * @throws MWException
1131          * @return ContentHandler
1132          */
1133         public function getContentHandler() {
1134                 if ( !$this->mContentHandler ) {
1135                         $model = $this->getContentModel();
1136                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1137
1138                         $format = $this->getContentFormat();
1139
1140                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1141                                 throw new MWException( "Oops, the content format $format is not supported for "
1142                                         . "this content model, $model" );
1143                         }
1144                 }
1145
1146                 return $this->mContentHandler;
1147         }
1148
1149         /**
1150          * @return string
1151          */
1152         public function getTimestamp() {
1153                 return wfTimestamp( TS_MW, $this->mTimestamp );
1154         }
1155
1156         /**
1157          * @return bool
1158          */
1159         public function isCurrent() {
1160                 return $this->mCurrent;
1161         }
1162
1163         /**
1164          * Get previous revision for this title
1165          *
1166          * @return Revision|null
1167          */
1168         public function getPrevious() {
1169                 if ( $this->getTitle() ) {
1170                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1171                         if ( $prev ) {
1172                                 return self::newFromTitle( $this->getTitle(), $prev );
1173                         }
1174                 }
1175                 return null;
1176         }
1177
1178         /**
1179          * Get next revision for this title
1180          *
1181          * @return Revision|null
1182          */
1183         public function getNext() {
1184                 if ( $this->getTitle() ) {
1185                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1186                         if ( $next ) {
1187                                 return self::newFromTitle( $this->getTitle(), $next );
1188                         }
1189                 }
1190                 return null;
1191         }
1192
1193         /**
1194          * Get previous revision Id for this page_id
1195          * This is used to populate rev_parent_id on save
1196          *
1197          * @param IDatabase $db
1198          * @return int
1199          */
1200         private function getPreviousRevisionId( $db ) {
1201                 if ( $this->mPage === null ) {
1202                         return 0;
1203                 }
1204                 # Use page_latest if ID is not given
1205                 if ( !$this->mId ) {
1206                         $prevId = $db->selectField( 'page', 'page_latest',
1207                                 [ 'page_id' => $this->mPage ],
1208                                 __METHOD__ );
1209                 } else {
1210                         $prevId = $db->selectField( 'revision', 'rev_id',
1211                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1212                                 __METHOD__,
1213                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1214                 }
1215                 return intval( $prevId );
1216         }
1217
1218         /**
1219          * Get revision text associated with an old or archive row
1220          * $row is usually an object from wfFetchRow(), both the flags and the text
1221          * field must be included.
1222          *
1223          * @param stdClass $row The text data
1224          * @param string $prefix Table prefix (default 'old_')
1225          * @param string|bool $wiki The name of the wiki to load the revision text from
1226          *   (same as the the wiki $row was loaded from) or false to indicate the local
1227          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1228          *   identifier as understood by the LoadBalancer class.
1229          * @return string Text the text requested or false on failure
1230          */
1231         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1232
1233                 # Get data
1234                 $textField = $prefix . 'text';
1235                 $flagsField = $prefix . 'flags';
1236
1237                 if ( isset( $row->$flagsField ) ) {
1238                         $flags = explode( ',', $row->$flagsField );
1239                 } else {
1240                         $flags = [];
1241                 }
1242
1243                 if ( isset( $row->$textField ) ) {
1244                         $text = $row->$textField;
1245                 } else {
1246                         return false;
1247                 }
1248
1249                 # Use external methods for external objects, text in table is URL-only then
1250                 if ( in_array( 'external', $flags ) ) {
1251                         $url = $text;
1252                         $parts = explode( '://', $url, 2 );
1253                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1254                                 return false;
1255                         }
1256                         $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1257                 }
1258
1259                 // If the text was fetched without an error, convert it
1260                 if ( $text !== false ) {
1261                         $text = self::decompressRevisionText( $text, $flags );
1262                 }
1263                 return $text;
1264         }
1265
1266         /**
1267          * If $wgCompressRevisions is enabled, we will compress data.
1268          * The input string is modified in place.
1269          * Return value is the flags field: contains 'gzip' if the
1270          * data is compressed, and 'utf-8' if we're saving in UTF-8
1271          * mode.
1272          *
1273          * @param mixed $text Reference to a text
1274          * @return string
1275          */
1276         public static function compressRevisionText( &$text ) {
1277                 global $wgCompressRevisions;
1278                 $flags = [];
1279
1280                 # Revisions not marked this way will be converted
1281                 # on load if $wgLegacyCharset is set in the future.
1282                 $flags[] = 'utf-8';
1283
1284                 if ( $wgCompressRevisions ) {
1285                         if ( function_exists( 'gzdeflate' ) ) {
1286                                 $deflated = gzdeflate( $text );
1287
1288                                 if ( $deflated === false ) {
1289                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1290                                 } else {
1291                                         $text = $deflated;
1292                                         $flags[] = 'gzip';
1293                                 }
1294                         } else {
1295                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1296                         }
1297                 }
1298                 return implode( ',', $flags );
1299         }
1300
1301         /**
1302          * Re-converts revision text according to it's flags.
1303          *
1304          * @param mixed $text Reference to a text
1305          * @param array $flags Compression flags
1306          * @return string|bool Decompressed text, or false on failure
1307          */
1308         public static function decompressRevisionText( $text, $flags ) {
1309                 if ( in_array( 'gzip', $flags ) ) {
1310                         # Deal with optional compression of archived pages.
1311                         # This can be done periodically via maintenance/compressOld.php, and
1312                         # as pages are saved if $wgCompressRevisions is set.
1313                         $text = gzinflate( $text );
1314
1315                         if ( $text === false ) {
1316                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1317                                 return false;
1318                         }
1319                 }
1320
1321                 if ( in_array( 'object', $flags ) ) {
1322                         # Generic compressed storage
1323                         $obj = unserialize( $text );
1324                         if ( !is_object( $obj ) ) {
1325                                 // Invalid object
1326                                 return false;
1327                         }
1328                         $text = $obj->getText();
1329                 }
1330
1331                 global $wgLegacyEncoding;
1332                 if ( $text !== false && $wgLegacyEncoding
1333                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1334                 ) {
1335                         # Old revisions kept around in a legacy encoding?
1336                         # Upconvert on demand.
1337                         # ("utf8" checked for compatibility with some broken
1338                         #  conversion scripts 2008-12-30)
1339                         global $wgContLang;
1340                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1341                 }
1342
1343                 return $text;
1344         }
1345
1346         /**
1347          * Insert a new revision into the database, returning the new revision ID
1348          * number on success and dies horribly on failure.
1349          *
1350          * @param IDatabase $dbw (master connection)
1351          * @throws MWException
1352          * @return int
1353          */
1354         public function insertOn( $dbw ) {
1355                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1356
1357                 // Not allowed to have rev_page equal to 0, false, etc.
1358                 if ( !$this->mPage ) {
1359                         $title = $this->getTitle();
1360                         if ( $title instanceof Title ) {
1361                                 $titleText = ' for page ' . $title->getPrefixedText();
1362                         } else {
1363                                 $titleText = '';
1364                         }
1365                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1366                 }
1367
1368                 $this->checkContentModel();
1369
1370                 $data = $this->mText;
1371                 $flags = self::compressRevisionText( $data );
1372
1373                 # Write to external storage if required
1374                 if ( $wgDefaultExternalStore ) {
1375                         // Store and get the URL
1376                         $data = ExternalStore::insertToDefault( $data );
1377                         if ( !$data ) {
1378                                 throw new MWException( "Unable to store text to external storage" );
1379                         }
1380                         if ( $flags ) {
1381                                 $flags .= ',';
1382                         }
1383                         $flags .= 'external';
1384                 }
1385
1386                 # Record the text (or external storage URL) to the text table
1387                 if ( $this->mTextId === null ) {
1388                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1389                         $dbw->insert( 'text',
1390                                 [
1391                                         'old_id' => $old_id,
1392                                         'old_text' => $data,
1393                                         'old_flags' => $flags,
1394                                 ], __METHOD__
1395                         );
1396                         $this->mTextId = $dbw->insertId();
1397                 }
1398
1399                 if ( $this->mComment === null ) {
1400                         $this->mComment = "";
1401                 }
1402
1403                 # Record the edit in revisions
1404                 $rev_id = $this->mId !== null
1405                         ? $this->mId
1406                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1407                 $row = [
1408                         'rev_id'         => $rev_id,
1409                         'rev_page'       => $this->mPage,
1410                         'rev_text_id'    => $this->mTextId,
1411                         'rev_comment'    => $this->mComment,
1412                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1413                         'rev_user'       => $this->mUser,
1414                         'rev_user_text'  => $this->mUserText,
1415                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1416                         'rev_deleted'    => $this->mDeleted,
1417                         'rev_len'        => $this->mSize,
1418                         'rev_parent_id'  => $this->mParentId === null
1419                                 ? $this->getPreviousRevisionId( $dbw )
1420                                 : $this->mParentId,
1421                         'rev_sha1'       => $this->mSha1 === null
1422                                 ? Revision::base36Sha1( $this->mText )
1423                                 : $this->mSha1,
1424                 ];
1425
1426                 if ( $wgContentHandlerUseDB ) {
1427                         // NOTE: Store null for the default model and format, to save space.
1428                         // XXX: Makes the DB sensitive to changed defaults.
1429                         // Make this behavior optional? Only in miser mode?
1430
1431                         $model = $this->getContentModel();
1432                         $format = $this->getContentFormat();
1433
1434                         $title = $this->getTitle();
1435
1436                         if ( $title === null ) {
1437                                 throw new MWException( "Insufficient information to determine the title of the "
1438                                         . "revision's page!" );
1439                         }
1440
1441                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1442                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1443
1444                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1445                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1446                 }
1447
1448                 $dbw->insert( 'revision', $row, __METHOD__ );
1449
1450                 $this->mId = $rev_id !== null ? $rev_id : $dbw->insertId();
1451
1452                 // Assertion to try to catch T92046
1453                 if ( (int)$this->mId === 0 ) {
1454                         throw new UnexpectedValueException(
1455                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1456                                         var_export( $row, 1 )
1457                         );
1458                 }
1459
1460                 Hooks::run( 'RevisionInsertComplete', [ &$this, $data, $flags ] );
1461
1462                 return $this->mId;
1463         }
1464
1465         protected function checkContentModel() {
1466                 global $wgContentHandlerUseDB;
1467
1468                 // Note: may return null for revisions that have not yet been inserted
1469                 $title = $this->getTitle();
1470
1471                 $model = $this->getContentModel();
1472                 $format = $this->getContentFormat();
1473                 $handler = $this->getContentHandler();
1474
1475                 if ( !$handler->isSupportedFormat( $format ) ) {
1476                         $t = $title->getPrefixedDBkey();
1477
1478                         throw new MWException( "Can't use format $format with content model $model on $t" );
1479                 }
1480
1481                 if ( !$wgContentHandlerUseDB && $title ) {
1482                         // if $wgContentHandlerUseDB is not set,
1483                         // all revisions must use the default content model and format.
1484
1485                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1486                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1487                         $defaultFormat = $defaultHandler->getDefaultFormat();
1488
1489                         if ( $this->getContentModel() != $defaultModel ) {
1490                                 $t = $title->getPrefixedDBkey();
1491
1492                                 throw new MWException( "Can't save non-default content model with "
1493                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1494                                         . "default for $t is $defaultModel" );
1495                         }
1496
1497                         if ( $this->getContentFormat() != $defaultFormat ) {
1498                                 $t = $title->getPrefixedDBkey();
1499
1500                                 throw new MWException( "Can't use non-default content format with "
1501                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1502                                         . "default for $t is $defaultFormat" );
1503                         }
1504                 }
1505
1506                 $content = $this->getContent( Revision::RAW );
1507                 $prefixedDBkey = $title->getPrefixedDBkey();
1508                 $revId = $this->mId;
1509
1510                 if ( !$content ) {
1511                         throw new MWException(
1512                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1513                         );
1514                 }
1515                 if ( !$content->isValid() ) {
1516                         throw new MWException(
1517                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1518                         );
1519                 }
1520         }
1521
1522         /**
1523          * Get the base 36 SHA-1 value for a string of text
1524          * @param string $text
1525          * @return string
1526          */
1527         public static function base36Sha1( $text ) {
1528                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1529         }
1530
1531         /**
1532          * Lazy-load the revision's text.
1533          * Currently hardcoded to the 'text' table storage engine.
1534          *
1535          * @return string|bool The revision's text, or false on failure
1536          */
1537         protected function loadText() {
1538                 // Caching may be beneficial for massive use of external storage
1539                 global $wgRevisionCacheExpiry;
1540                 static $processCache = null;
1541
1542                 if ( !$processCache ) {
1543                         $processCache = new MapCacheLRU( 10 );
1544                 }
1545
1546                 $cache = ObjectCache::getMainWANInstance();
1547                 $textId = $this->getTextId();
1548                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1549
1550                 if ( $wgRevisionCacheExpiry ) {
1551                         if ( $processCache->has( $key ) ) {
1552                                 return $processCache->get( $key );
1553                         }
1554                         $text = $cache->get( $key );
1555                         if ( is_string( $text ) ) {
1556                                 $processCache->set( $key, $text );
1557                                 return $text;
1558                         }
1559                 }
1560
1561                 // If we kept data for lazy extraction, use it now...
1562                 if ( $this->mTextRow !== null ) {
1563                         $row = $this->mTextRow;
1564                         $this->mTextRow = null;
1565                 } else {
1566                         $row = null;
1567                 }
1568
1569                 if ( !$row ) {
1570                         // Text data is immutable; check slaves first.
1571                         $dbr = wfGetDB( DB_SLAVE );
1572                         $row = $dbr->selectRow( 'text',
1573                                 [ 'old_text', 'old_flags' ],
1574                                 [ 'old_id' => $textId ],
1575                                 __METHOD__ );
1576                 }
1577
1578                 // Fallback to the master in case of slave lag. Also use FOR UPDATE if it was
1579                 // used to fetch this revision to avoid missing the row due to REPEATABLE-READ.
1580                 $forUpdate = ( $this->mQueryFlags & self::READ_LOCKING == self::READ_LOCKING );
1581                 if ( !$row && ( $forUpdate || wfGetLB()->getServerCount() > 1 ) ) {
1582                         $dbw = wfGetDB( DB_MASTER );
1583                         $row = $dbw->selectRow( 'text',
1584                                 [ 'old_text', 'old_flags' ],
1585                                 [ 'old_id' => $textId ],
1586                                 __METHOD__,
1587                                 $forUpdate ? [ 'FOR UPDATE' ] : [] );
1588                 }
1589
1590                 if ( !$row ) {
1591                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1592                 }
1593
1594                 $text = self::getRevisionText( $row );
1595                 if ( $row && $text === false ) {
1596                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1597                 }
1598
1599                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1600                 if ( $wgRevisionCacheExpiry && $text !== false ) {
1601                         $processCache->set( $key, $text );
1602                         $cache->set( $key, $text, $wgRevisionCacheExpiry );
1603                 }
1604
1605                 return $text;
1606         }
1607
1608         /**
1609          * Create a new null-revision for insertion into a page's
1610          * history. This will not re-save the text, but simply refer
1611          * to the text from the previous version.
1612          *
1613          * Such revisions can for instance identify page rename
1614          * operations and other such meta-modifications.
1615          *
1616          * @param IDatabase $dbw
1617          * @param int $pageId ID number of the page to read from
1618          * @param string $summary Revision's summary
1619          * @param bool $minor Whether the revision should be considered as minor
1620          * @param User|null $user User object to use or null for $wgUser
1621          * @return Revision|null Revision or null on error
1622          */
1623         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1624                 global $wgContentHandlerUseDB, $wgContLang;
1625
1626                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1627                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1628
1629                 if ( $wgContentHandlerUseDB ) {
1630                         $fields[] = 'rev_content_model';
1631                         $fields[] = 'rev_content_format';
1632                 }
1633
1634                 $current = $dbw->selectRow(
1635                         [ 'page', 'revision' ],
1636                         $fields,
1637                         [
1638                                 'page_id' => $pageId,
1639                                 'page_latest=rev_id',
1640                         ],
1641                         __METHOD__,
1642                         [ 'FOR UPDATE' ] // T51581
1643                 );
1644
1645                 if ( $current ) {
1646                         if ( !$user ) {
1647                                 global $wgUser;
1648                                 $user = $wgUser;
1649                         }
1650
1651                         // Truncate for whole multibyte characters
1652                         $summary = $wgContLang->truncate( $summary, 255 );
1653
1654                         $row = [
1655                                 'page'       => $pageId,
1656                                 'user_text'  => $user->getName(),
1657                                 'user'       => $user->getId(),
1658                                 'comment'    => $summary,
1659                                 'minor_edit' => $minor,
1660                                 'text_id'    => $current->rev_text_id,
1661                                 'parent_id'  => $current->page_latest,
1662                                 'len'        => $current->rev_len,
1663                                 'sha1'       => $current->rev_sha1
1664                         ];
1665
1666                         if ( $wgContentHandlerUseDB ) {
1667                                 $row['content_model'] = $current->rev_content_model;
1668                                 $row['content_format'] = $current->rev_content_format;
1669                         }
1670
1671                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1672
1673                         $revision = new Revision( $row );
1674                 } else {
1675                         $revision = null;
1676                 }
1677
1678                 return $revision;
1679         }
1680
1681         /**
1682          * Determine if the current user is allowed to view a particular
1683          * field of this revision, if it's marked as deleted.
1684          *
1685          * @param int $field One of self::DELETED_TEXT,
1686          *                              self::DELETED_COMMENT,
1687          *                              self::DELETED_USER
1688          * @param User|null $user User object to check, or null to use $wgUser
1689          * @return bool
1690          */
1691         public function userCan( $field, User $user = null ) {
1692                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1693         }
1694
1695         /**
1696          * Determine if the current user is allowed to view a particular
1697          * field of this revision, if it's marked as deleted. This is used
1698          * by various classes to avoid duplication.
1699          *
1700          * @param int $bitfield Current field
1701          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1702          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1703          *                               self::DELETED_USER = File::DELETED_USER
1704          * @param User|null $user User object to check, or null to use $wgUser
1705          * @param Title|null $title A Title object to check for per-page restrictions on,
1706          *                          instead of just plain userrights
1707          * @return bool
1708          */
1709         public static function userCanBitfield( $bitfield, $field, User $user = null,
1710                 Title $title = null
1711         ) {
1712                 if ( $bitfield & $field ) { // aspect is deleted
1713                         if ( $user === null ) {
1714                                 global $wgUser;
1715                                 $user = $wgUser;
1716                         }
1717                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1718                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1719                         } elseif ( $field & self::DELETED_TEXT ) {
1720                                 $permissions = [ 'deletedtext' ];
1721                         } else {
1722                                 $permissions = [ 'deletedhistory' ];
1723                         }
1724                         $permissionlist = implode( ', ', $permissions );
1725                         if ( $title === null ) {
1726                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1727                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1728                         } else {
1729                                 $text = $title->getPrefixedText();
1730                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1731                                 foreach ( $permissions as $perm ) {
1732                                         if ( $title->userCan( $perm, $user ) ) {
1733                                                 return true;
1734                                         }
1735                                 }
1736                                 return false;
1737                         }
1738                 } else {
1739                         return true;
1740                 }
1741         }
1742
1743         /**
1744          * Get rev_timestamp from rev_id, without loading the rest of the row
1745          *
1746          * @param Title $title
1747          * @param int $id
1748          * @return string|bool False if not found
1749          */
1750         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1751                 $db = ( $flags & self::READ_LATEST )
1752                         ? wfGetDB( DB_MASTER )
1753                         : wfGetDB( DB_SLAVE );
1754                 // Casting fix for databases that can't take '' for rev_id
1755                 if ( $id == '' ) {
1756                         $id = 0;
1757                 }
1758                 $conds = [ 'rev_id' => $id ];
1759                 $conds['rev_page'] = $title->getArticleID();
1760                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1761
1762                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
1763         }
1764
1765         /**
1766          * Get count of revisions per page...not very efficient
1767          *
1768          * @param IDatabase $db
1769          * @param int $id Page id
1770          * @return int
1771          */
1772         static function countByPageId( $db, $id ) {
1773                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
1774                         [ 'rev_page' => $id ], __METHOD__ );
1775                 if ( $row ) {
1776                         return $row->revCount;
1777                 }
1778                 return 0;
1779         }
1780
1781         /**
1782          * Get count of revisions per page...not very efficient
1783          *
1784          * @param IDatabase $db
1785          * @param Title $title
1786          * @return int
1787          */
1788         static function countByTitle( $db, $title ) {
1789                 $id = $title->getArticleID();
1790                 if ( $id ) {
1791                         return self::countByPageId( $db, $id );
1792                 }
1793                 return 0;
1794         }
1795
1796         /**
1797          * Check if no edits were made by other users since
1798          * the time a user started editing the page. Limit to
1799          * 50 revisions for the sake of performance.
1800          *
1801          * @since 1.20
1802          * @deprecated since 1.24
1803          *
1804          * @param IDatabase|int $db The Database to perform the check on. May be given as a
1805          *        Database object or a database identifier usable with wfGetDB.
1806          * @param int $pageId The ID of the page in question
1807          * @param int $userId The ID of the user in question
1808          * @param string $since Look at edits since this time
1809          *
1810          * @return bool True if the given user was the only one to edit since the given timestamp
1811          */
1812         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1813                 if ( !$userId ) {
1814                         return false;
1815                 }
1816
1817                 if ( is_int( $db ) ) {
1818                         $db = wfGetDB( $db );
1819                 }
1820
1821                 $res = $db->select( 'revision',
1822                         'rev_user',
1823                         [
1824                                 'rev_page' => $pageId,
1825                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1826                         ],
1827                         __METHOD__,
1828                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
1829                 foreach ( $res as $row ) {
1830                         if ( $row->rev_user != $userId ) {
1831                                 return false;
1832                         }
1833                 }
1834                 return true;
1835         }
1836 }