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