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 use MediaWiki\MediaWikiServices;
  24
  25 /**
  26  * @todo document
  27  */
  28 class Revision implements IDBAccessObject {
  29         /** @var int|null */
  30         protected $mId;
  31         /** @var int|null */
  32         protected $mPage;
  33         /** @var string */
  34         protected $mUserText;
  35         /** @var string */
  36         protected $mOrigUserText;
  37         /** @var int */
  38         protected $mUser;
  39         /** @var bool */
  40         protected $mMinorEdit;
  41         /** @var string */
  42         protected $mTimestamp;
  43         /** @var int */
  44         protected $mDeleted;
  45         /** @var int */
  46         protected $mSize;
  47         /** @var string */
  48         protected $mSha1;
  49         /** @var int */
  50         protected $mParentId;
  51         /** @var string */
  52         protected $mComment;
  53         /** @var string */
  54         protected $mText;
  55         /** @var int */
  56         protected $mTextId;
  57         /** @var int */
  58         protected $mUnpatrolled;
  59
  60         /** @var stdClass|null */
  61         protected $mTextRow;
  62
  63         /**  @var null|Title */
  64         protected $mTitle;
  65         /** @var bool */
  66         protected $mCurrent;
  67         /** @var string */
  68         protected $mContentModel;
  69         /** @var string */
  70         protected $mContentFormat;
  71
  72         /** @var Content|null|bool */
  73         protected $mContent;
  74         /** @var null|ContentHandler */
  75         protected $mContentHandler;
  76
  77         /** @var int */
  78         protected $mQueryFlags = 0;
  79         /** @var bool Used for cached values to reload user text and rev_deleted */
  80         protected $mRefreshMutableFields = false;
  81         /** @var string Wiki ID; false means the current wiki */
  82         protected $mWiki = false;
  83
  84         // Revision deletion constants
  85         const DELETED_TEXT = 1;
  86         const DELETED_COMMENT = 2;
  87         const DELETED_USER = 4;
  88         const DELETED_RESTRICTED = 8;
  89         const SUPPRESSED_USER = 12; // convenience
  90
  91         // Audience options for accessors
  92         const FOR_PUBLIC = 1;
  93         const FOR_THIS_USER = 2;
  94         const RAW = 3;
  95
  96         const TEXT_CACHE_GROUP = 'revisiontext:10'; // process cache name and max key count
  97
  98         /**
  99          * Load a page revision from a given revision ID number.
 100          * Returns null if no such revision can be found.
 101          *
 102          * $flags include:
 103          *      Revision::READ_LATEST  : Select the data from the master
 104          *      Revision::READ_LOCKING : Select & lock the data from the master
 105          *
 106          * @param int $id
 107          * @param int $flags (optional)
 108          * @return Revision|null
 109          */
 110         public static function newFromId( $id, $flags = 0 ) {
 111                 return self::newFromConds( [ 'rev_id' => intval( $id ) ], $flags );
 112         }
 113
 114         /**
 115          * Load either the current, or a specified, revision
 116          * that's attached to a given link target. If not attached
 117          * to that link target, will return null.
 118          *
 119          * $flags include:
 120          *      Revision::READ_LATEST  : Select the data from the master
 121          *      Revision::READ_LOCKING : Select & lock the data from the master
 122          *
 123          * @param LinkTarget $linkTarget
 124          * @param int $id (optional)
 125          * @param int $flags Bitfield (optional)
 126          * @return Revision|null
 127          */
 128         public static function newFromTitle( LinkTarget $linkTarget, $id = 0, $flags = 0 ) {
 129                 $conds = [
 130                         'page_namespace' => $linkTarget->getNamespace(),
 131                         'page_title' => $linkTarget->getDBkey()
 132                 ];
 133                 if ( $id ) {
 134                         // Use the specified ID
 135                         $conds['rev_id'] = $id;
 136                         return self::newFromConds( $conds, $flags );
 137                 } else {
 138                         // Use a join to get the latest revision
 139                         $conds[] = 'rev_id=page_latest';
 140                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 141                         return self::loadFromConds( $db, $conds, $flags );
 142                 }
 143         }
 144
 145         /**
 146          * Load either the current, or a specified, revision
 147          * that's attached to a given page ID.
 148          * Returns null if no such revision can be found.
 149          *
 150          * $flags include:
 151          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 152          *      Revision::READ_LOCKING : Select & lock the data from the master
 153          *
 154          * @param int $pageId
 155          * @param int $revId (optional)
 156          * @param int $flags Bitfield (optional)
 157          * @return Revision|null
 158          */
 159         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 160                 $conds = [ 'page_id' => $pageId ];
 161                 if ( $revId ) {
 162                         $conds['rev_id'] = $revId;
 163                         return self::newFromConds( $conds, $flags );
 164                 } else {
 165                         // Use a join to get the latest revision
 166                         $conds[] = 'rev_id = page_latest';
 167                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 168                         return self::loadFromConds( $db, $conds, $flags );
 169                 }
 170         }
 171
 172         /**
 173          * Make a fake revision object from an archive table row. This is queried
 174          * for permissions or even inserted (as in Special:Undelete)
 175          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 176          *
 177          * @param object $row
 178          * @param array $overrides
 179          *
 180          * @throws MWException
 181          * @return Revision
 182          */
 183         public static function newFromArchiveRow( $row, $overrides = [] ) {
 184                 global $wgContentHandlerUseDB;
 185
 186                 $attribs = $overrides + [
 187                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 188                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 189                         'comment'    => $row->ar_comment,
 190                         'user'       => $row->ar_user,
 191                         'user_text'  => $row->ar_user_text,
 192                         'timestamp'  => $row->ar_timestamp,
 193                         'minor_edit' => $row->ar_minor_edit,
 194                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 195                         'deleted'    => $row->ar_deleted,
 196                         'len'        => $row->ar_len,
 197                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 198                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 199                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 200                 ];
 201
 202                 if ( !$wgContentHandlerUseDB ) {
 203                         unset( $attribs['content_model'] );
 204                         unset( $attribs['content_format'] );
 205                 }
 206
 207                 if ( !isset( $attribs['title'] )
 208                         && isset( $row->ar_namespace )
 209                         && isset( $row->ar_title )
 210                 ) {
 211                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 212                 }
 213
 214                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 215                         // Pre-1.5 ar_text row
 216                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 217                         if ( $attribs['text'] === false ) {
 218                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 219                         }
 220                 }
 221                 return new self( $attribs );
 222         }
 223
 224         /**
 225          * @since 1.19
 226          *
 227          * @param object $row
 228          * @return Revision
 229          */
 230         public static function newFromRow( $row ) {
 231                 return new self( $row );
 232         }
 233
 234         /**
 235          * Load a page revision from a given revision ID number.
 236          * Returns null if no such revision can be found.
 237          *
 238          * @param IDatabase $db
 239          * @param int $id
 240          * @return Revision|null
 241          */
 242         public static function loadFromId( $db, $id ) {
 243                 return self::loadFromConds( $db, [ 'rev_id' => intval( $id ) ] );
 244         }
 245
 246         /**
 247          * Load either the current, or a specified, revision
 248          * that's attached to a given page. If not attached
 249          * to that page, will return null.
 250          *
 251          * @param IDatabase $db
 252          * @param int $pageid
 253          * @param int $id
 254          * @return Revision|null
 255          */
 256         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 257                 $conds = [ 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) ];
 258                 if ( $id ) {
 259                         $conds['rev_id'] = intval( $id );
 260                 } else {
 261                         $conds[] = 'rev_id=page_latest';
 262                 }
 263                 return self::loadFromConds( $db, $conds );
 264         }
 265
 266         /**
 267          * Load either the current, or a specified, revision
 268          * that's attached to a given page. If not attached
 269          * to that page, will return null.
 270          *
 271          * @param IDatabase $db
 272          * @param Title $title
 273          * @param int $id
 274          * @return Revision|null
 275          */
 276         public static function loadFromTitle( $db, $title, $id = 0 ) {
 277                 if ( $id ) {
 278                         $matchId = intval( $id );
 279                 } else {
 280                         $matchId = 'page_latest';
 281                 }
 282                 return self::loadFromConds( $db,
 283                         [
 284                                 "rev_id=$matchId",
 285                                 'page_namespace' => $title->getNamespace(),
 286                                 'page_title' => $title->getDBkey()
 287                         ]
 288                 );
 289         }
 290
 291         /**
 292          * Load the revision for the given title with the given timestamp.
 293          * WARNING: Timestamps may in some circumstances not be unique,
 294          * so this isn't the best key to use.
 295          *
 296          * @param IDatabase $db
 297          * @param Title $title
 298          * @param string $timestamp
 299          * @return Revision|null
 300          */
 301         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 302                 return self::loadFromConds( $db,
 303                         [
 304                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 305                                 'page_namespace' => $title->getNamespace(),
 306                                 'page_title' => $title->getDBkey()
 307                         ]
 308                 );
 309         }
 310
 311         /**
 312          * Given a set of conditions, fetch a revision
 313          *
 314          * This method is used then a revision ID is qualified and
 315          * will incorporate some basic replica DB/master fallback logic
 316          *
 317          * @param array $conditions
 318          * @param int $flags (optional)
 319          * @return Revision|null
 320          */
 321         private static function newFromConds( $conditions, $flags = 0 ) {
 322                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 323
 324                 $rev = self::loadFromConds( $db, $conditions, $flags );
 325                 // Make sure new pending/committed revision are visibile later on
 326                 // within web requests to certain avoid bugs like T93866 and T94407.
 327                 if ( !$rev
 328                         && !( $flags & self::READ_LATEST )
 329                         && wfGetLB()->getServerCount() > 1
 330                         && wfGetLB()->hasOrMadeRecentMasterChanges()
 331                 ) {
 332                         $flags = self::READ_LATEST;
 333                         $db = wfGetDB( DB_MASTER );
 334                         $rev = self::loadFromConds( $db, $conditions, $flags );
 335                 }
 336
 337                 if ( $rev ) {
 338                         $rev->mQueryFlags = $flags;
 339                 }
 340
 341                 return $rev;
 342         }
 343
 344         /**
 345          * Given a set of conditions, fetch a revision from
 346          * the given database connection.
 347          *
 348          * @param IDatabase $db
 349          * @param array $conditions
 350          * @param int $flags (optional)
 351          * @return Revision|null
 352          */
 353         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 354                 $row = self::fetchFromConds( $db, $conditions, $flags );
 355                 if ( $row ) {
 356                         $rev = new Revision( $row );
 357                         $rev->mWiki = $db->getWikiID();
 358
 359                         return $rev;
 360                 }
 361
 362                 return null;
 363         }
 364
 365         /**
 366          * Return a wrapper for a series of database rows to
 367          * fetch all of a given page's revisions in turn.
 368          * Each row can be fed to the constructor to get objects.
 369          *
 370          * @param LinkTarget $title
 371          * @return ResultWrapper
 372          * @deprecated Since 1.28
 373          */
 374         public static function fetchRevision( LinkTarget $title ) {
 375                 $row = self::fetchFromConds(
 376                         wfGetDB( DB_REPLICA ),
 377                         [
 378                                 'rev_id=page_latest',
 379                                 'page_namespace' => $title->getNamespace(),
 380                                 'page_title' => $title->getDBkey()
 381                         ]
 382                 );
 383
 384                 return new FakeResultWrapper( $row ? [ $row ] : [] );
 385         }
 386
 387         /**
 388          * Given a set of conditions, return a ResultWrapper
 389          * which will return matching database rows with the
 390          * fields necessary to build Revision objects.
 391          *
 392          * @param IDatabase $db
 393          * @param array $conditions
 394          * @param int $flags (optional)
 395          * @return stdClass
 396          */
 397         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 398                 $fields = array_merge(
 399                         self::selectFields(),
 400                         self::selectPageFields(),
 401                         self::selectUserFields()
 402                 );
 403                 $options = [];
 404                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 405                         $options[] = 'FOR UPDATE';
 406                 }
 407                 return $db->selectRow(
 408                         [ 'revision', 'page', 'user' ],
 409                         $fields,
 410                         $conditions,
 411                         __METHOD__,
 412                         $options,
 413                         [ 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() ]
 414                 );
 415         }
 416
 417         /**
 418          * Return the value of a select() JOIN conds array for the user table.
 419          * This will get user table rows for logged-in users.
 420          * @since 1.19
 421          * @return array
 422          */
 423         public static function userJoinCond() {
 424                 return [ 'LEFT JOIN', [ 'rev_user != 0', 'user_id = rev_user' ] ];
 425         }
 426
 427         /**
 428          * Return the value of a select() page conds array for the page table.
 429          * This will assure that the revision(s) are not orphaned from live pages.
 430          * @since 1.19
 431          * @return array
 432          */
 433         public static function pageJoinCond() {
 434                 return [ 'INNER JOIN', [ 'page_id = rev_page' ] ];
 435         }
 436
 437         /**
 438          * Return the list of revision fields that should be selected to create
 439          * a new revision.
 440          * @return array
 441          */
 442         public static function selectFields() {
 443                 global $wgContentHandlerUseDB;
 444
 445                 $fields = [
 446                         'rev_id',
 447                         'rev_page',
 448                         'rev_text_id',
 449                         'rev_timestamp',
 450                         'rev_comment',
 451                         'rev_user_text',
 452                         'rev_user',
 453                         'rev_minor_edit',
 454                         'rev_deleted',
 455                         'rev_len',
 456                         'rev_parent_id',
 457                         'rev_sha1',
 458                 ];
 459
 460                 if ( $wgContentHandlerUseDB ) {
 461                         $fields[] = 'rev_content_format';
 462                         $fields[] = 'rev_content_model';
 463                 }
 464
 465                 return $fields;
 466         }
 467
 468         /**
 469          * Return the list of revision fields that should be selected to create
 470          * a new revision from an archive row.
 471          * @return array
 472          */
 473         public static function selectArchiveFields() {
 474                 global $wgContentHandlerUseDB;
 475                 $fields = [
 476                         'ar_id',
 477                         'ar_page_id',
 478                         'ar_rev_id',
 479                         'ar_text',
 480                         'ar_text_id',
 481                         'ar_timestamp',
 482                         'ar_comment',
 483                         'ar_user_text',
 484                         'ar_user',
 485                         'ar_minor_edit',
 486                         'ar_deleted',
 487                         'ar_len',
 488                         'ar_parent_id',
 489                         'ar_sha1',
 490                 ];
 491
 492                 if ( $wgContentHandlerUseDB ) {
 493                         $fields[] = 'ar_content_format';
 494                         $fields[] = 'ar_content_model';
 495                 }
 496                 return $fields;
 497         }
 498
 499         /**
 500          * Return the list of text fields that should be selected to read the
 501          * revision text
 502          * @return array
 503          */
 504         public static function selectTextFields() {
 505                 return [
 506                         'old_text',
 507                         'old_flags'
 508                 ];
 509         }
 510
 511         /**
 512          * Return the list of page fields that should be selected from page table
 513          * @return array
 514          */
 515         public static function selectPageFields() {
 516                 return [
 517                         'page_namespace',
 518                         'page_title',
 519                         'page_id',
 520                         'page_latest',
 521                         'page_is_redirect',
 522                         'page_len',
 523                 ];
 524         }
 525
 526         /**
 527          * Return the list of user fields that should be selected from user table
 528          * @return array
 529          */
 530         public static function selectUserFields() {
 531                 return [ 'user_name' ];
 532         }
 533
 534         /**
 535          * Do a batched query to get the parent revision lengths
 536          * @param IDatabase $db
 537          * @param array $revIds
 538          * @return array
 539          */
 540         public static function getParentLengths( $db, array $revIds ) {
 541                 $revLens = [];
 542                 if ( !$revIds ) {
 543                         return $revLens; // empty
 544                 }
 545                 $res = $db->select( 'revision',
 546                         [ 'rev_id', 'rev_len' ],
 547                         [ 'rev_id' => $revIds ],
 548                         __METHOD__ );
 549                 foreach ( $res as $row ) {
 550                         $revLens[$row->rev_id] = $row->rev_len;
 551                 }
 552                 return $revLens;
 553         }
 554
 555         /**
 556          * Constructor
 557          *
 558          * @param object|array $row Either a database row or an array
 559          * @throws MWException
 560          * @access private
 561          */
 562         function __construct( $row ) {
 563                 if ( is_object( $row ) ) {
 564                         $this->mId = intval( $row->rev_id );
 565                         $this->mPage = intval( $row->rev_page );
 566                         $this->mTextId = intval( $row->rev_text_id );
 567                         $this->mComment = $row->rev_comment;
 568                         $this->mUser = intval( $row->rev_user );
 569                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 570                         $this->mTimestamp = $row->rev_timestamp;
 571                         $this->mDeleted = intval( $row->rev_deleted );
 572
 573                         if ( !isset( $row->rev_parent_id ) ) {
 574                                 $this->mParentId = null;
 575                         } else {
 576                                 $this->mParentId = intval( $row->rev_parent_id );
 577                         }
 578
 579                         if ( !isset( $row->rev_len ) ) {
 580                                 $this->mSize = null;
 581                         } else {
 582                                 $this->mSize = intval( $row->rev_len );
 583                         }
 584
 585                         if ( !isset( $row->rev_sha1 ) ) {
 586                                 $this->mSha1 = null;
 587                         } else {
 588                                 $this->mSha1 = $row->rev_sha1;
 589                         }
 590
 591                         if ( isset( $row->page_latest ) ) {
 592                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 593                                 $this->mTitle = Title::newFromRow( $row );
 594                         } else {
 595                                 $this->mCurrent = false;
 596                                 $this->mTitle = null;
 597                         }
 598
 599                         if ( !isset( $row->rev_content_model ) ) {
 600                                 $this->mContentModel = null; # determine on demand if needed
 601                         } else {
 602                                 $this->mContentModel = strval( $row->rev_content_model );
 603                         }
 604
 605                         if ( !isset( $row->rev_content_format ) ) {
 606                                 $this->mContentFormat = null; # determine on demand if needed
 607                         } else {
 608                                 $this->mContentFormat = strval( $row->rev_content_format );
 609                         }
 610
 611                         // Lazy extraction...
 612                         $this->mText = null;
 613                         if ( isset( $row->old_text ) ) {
 614                                 $this->mTextRow = $row;
 615                         } else {
 616                                 // 'text' table row entry will be lazy-loaded
 617                                 $this->mTextRow = null;
 618                         }
 619
 620                         // Use user_name for users and rev_user_text for IPs...
 621                         $this->mUserText = null; // lazy load if left null
 622                         if ( $this->mUser == 0 ) {
 623                                 $this->mUserText = $row->rev_user_text; // IP user
 624                         } elseif ( isset( $row->user_name ) ) {
 625                                 $this->mUserText = $row->user_name; // logged-in user
 626                         }
 627                         $this->mOrigUserText = $row->rev_user_text;
 628                 } elseif ( is_array( $row ) ) {
 629                         // Build a new revision to be saved...
 630                         global $wgUser; // ugh
 631
 632                         # if we have a content object, use it to set the model and type
 633                         if ( !empty( $row['content'] ) ) {
 634                                 // @todo when is that set? test with external store setup! check out insertOn() [dk]
 635                                 if ( !empty( $row['text_id'] ) ) {
 636                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 637                                                 "can't serialize content object" );
 638                                 }
 639
 640                                 $row['content_model'] = $row['content']->getModel();
 641                                 # note: mContentFormat is initializes later accordingly
 642                                 # note: content is serialized later in this method!
 643                                 # also set text to null?
 644                         }
 645
 646                         $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 647                         $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 648                         $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 649                         $this->mUserText = isset( $row['user_text'] )
 650                                 ? strval( $row['user_text'] ) : $wgUser->getName();
 651                         $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 652                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 653                         $this->mTimestamp = isset( $row['timestamp'] )
 654                                 ? strval( $row['timestamp'] ) : wfTimestampNow();
 655                         $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 656                         $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 657                         $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 658                         $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 659
 660                         $this->mContentModel = isset( $row['content_model'] )
 661                                 ? strval( $row['content_model'] ) : null;
 662                         $this->mContentFormat = isset( $row['content_format'] )
 663                                 ? strval( $row['content_format'] ) : null;
 664
 665                         // Enforce spacing trimming on supplied text
 666                         $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 667                         $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 668                         $this->mTextRow = null;
 669
 670                         $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 671
 672                         // if we have a Content object, override mText and mContentModel
 673                         if ( !empty( $row['content'] ) ) {
 674                                 if ( !( $row['content'] instanceof Content ) ) {
 675                                         throw new MWException( '`content` field must contain a Content object.' );
 676                                 }
 677
 678                                 $handler = $this->getContentHandler();
 679                                 $this->mContent = $row['content'];
 680
 681                                 $this->mContentModel = $this->mContent->getModel();
 682                                 $this->mContentHandler = null;
 683
 684                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 685                         } elseif ( $this->mText !== null ) {
 686                                 $handler = $this->getContentHandler();
 687                                 $this->mContent = $handler->unserializeContent( $this->mText );
 688                         }
 689
 690                         // If we have a Title object, make sure it is consistent with mPage.
 691                         if ( $this->mTitle && $this->mTitle->exists() ) {
 692                                 if ( $this->mPage === null ) {
 693                                         // if the page ID wasn't known, set it now
 694                                         $this->mPage = $this->mTitle->getArticleID();
 695                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 696                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 697                                         // but it seems worth mentioning it in the log.
 698                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 699                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 700                                 }
 701                         }
 702
 703                         $this->mCurrent = false;
 704
 705                         // If we still have no length, see it we have the text to figure it out
 706                         if ( !$this->mSize && $this->mContent !== null ) {
 707                                 $this->mSize = $this->mContent->getSize();
 708                         }
 709
 710                         // Same for sha1
 711                         if ( $this->mSha1 === null ) {
 712                                 $this->mSha1 = $this->mText === null ? null : self::base36Sha1( $this->mText );
 713                         }
 714
 715                         // force lazy init
 716                         $this->getContentModel();
 717                         $this->getContentFormat();
 718                 } else {
 719                         throw new MWException( 'Revision constructor passed invalid row format.' );
 720                 }
 721                 $this->mUnpatrolled = null;
 722         }
 723
 724         /**
 725          * Get revision ID
 726          *
 727          * @return int|null
 728          */
 729         public function getId() {
 730                 return $this->mId;
 731         }
 732
 733         /**
 734          * Set the revision ID
 735          *
 736          * This should only be used for proposed revisions that turn out to be null edits
 737          *
 738          * @since 1.19
 739          * @param int $id
 740          */
 741         public function setId( $id ) {
 742                 $this->mId = (int)$id;
 743         }
 744
 745         /**
 746          * Set the user ID/name
 747          *
 748          * This should only be used for proposed revisions that turn out to be null edits
 749          *
 750          * @since 1.28
 751          * @param integer $id User ID
 752          * @param string $name User name
 753          */
 754         public function setUserIdAndName( $id, $name ) {
 755                 $this->mUser = (int)$id;
 756                 $this->mUserText = $name;
 757                 $this->mOrigUserText = $name;
 758         }
 759
 760         /**
 761          * Get text row ID
 762          *
 763          * @return int|null
 764          */
 765         public function getTextId() {
 766                 return $this->mTextId;
 767         }
 768
 769         /**
 770          * Get parent revision ID (the original previous page revision)
 771          *
 772          * @return int|null
 773          */
 774         public function getParentId() {
 775                 return $this->mParentId;
 776         }
 777
 778         /**
 779          * Returns the length of the text in this revision, or null if unknown.
 780          *
 781          * @return int|null
 782          */
 783         public function getSize() {
 784                 return $this->mSize;
 785         }
 786
 787         /**
 788          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 789          *
 790          * @return string|null
 791          */
 792         public function getSha1() {
 793                 return $this->mSha1;
 794         }
 795
 796         /**
 797          * Returns the title of the page associated with this entry or null.
 798          *
 799          * Will do a query, when title is not set and id is given.
 800          *
 801          * @return Title|null
 802          */
 803         public function getTitle() {
 804                 if ( $this->mTitle !== null ) {
 805                         return $this->mTitle;
 806                 }
 807                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 808                 if ( $this->mId !== null ) {
 809                         $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
 810                         $row = $dbr->selectRow(
 811                                 [ 'page', 'revision' ],
 812                                 self::selectPageFields(),
 813                                 [ 'page_id=rev_page', 'rev_id' => $this->mId ],
 814                                 __METHOD__
 815                         );
 816                         if ( $row ) {
 817                                 // @TODO: better foreign title handling
 818                                 $this->mTitle = Title::newFromRow( $row );
 819                         }
 820                 }
 821
 822                 if ( $this->mWiki === false || $this->mWiki === wfWikiID() ) {
 823                         // Loading by ID is best, though not possible for foreign titles
 824                         if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 825                                 $this->mTitle = Title::newFromID( $this->mPage );
 826                         }
 827                 }
 828
 829                 return $this->mTitle;
 830         }
 831
 832         /**
 833          * Set the title of the revision
 834          *
 835          * @param Title $title
 836          */
 837         public function setTitle( $title ) {
 838                 $this->mTitle = $title;
 839         }
 840
 841         /**
 842          * Get the page ID
 843          *
 844          * @return int|null
 845          */
 846         public function getPage() {
 847                 return $this->mPage;
 848         }
 849
 850         /**
 851          * Fetch revision's user id if it's available to the specified audience.
 852          * If the specified audience does not have access to it, zero will be
 853          * 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 ID 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 int
 862          */
 863         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 864                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 865                         return 0;
 866                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 867                         return 0;
 868                 } else {
 869                         return $this->mUser;
 870                 }
 871         }
 872
 873         /**
 874          * Fetch revision's user id without regard for the current user's permissions
 875          *
 876          * @return string
 877          * @deprecated since 1.25, use getUser( Revision::RAW )
 878          */
 879         public function getRawUser() {
 880                 wfDeprecated( __METHOD__, '1.25' );
 881                 return $this->getUser( self::RAW );
 882         }
 883
 884         /**
 885          * Fetch revision's username if it's available to the specified audience.
 886          * If the specified audience does not have access to the username, an
 887          * empty string will be returned.
 888          *
 889          * @param int $audience One of:
 890          *   Revision::FOR_PUBLIC       to be displayed to all users
 891          *   Revision::FOR_THIS_USER    to be displayed to the given user
 892          *   Revision::RAW              get the text regardless of permissions
 893          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 894          *   to the $audience parameter
 895          * @return string
 896          */
 897         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 898                 $this->loadMutableFields();
 899
 900                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 901                         return '';
 902                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 903                         return '';
 904                 } else {
 905                         if ( $this->mUserText === null ) {
 906                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 907                                 if ( $this->mUserText === false ) {
 908                                         # This shouldn't happen, but it can if the wiki was recovered
 909                                         # via importing revs and there is no user table entry yet.
 910                                         $this->mUserText = $this->mOrigUserText;
 911                                 }
 912                         }
 913                         return $this->mUserText;
 914                 }
 915         }
 916
 917         /**
 918          * Fetch revision's username without regard for view restrictions
 919          *
 920          * @return string
 921          * @deprecated since 1.25, use getUserText( Revision::RAW )
 922          */
 923         public function getRawUserText() {
 924                 wfDeprecated( __METHOD__, '1.25' );
 925                 return $this->getUserText( self::RAW );
 926         }
 927
 928         /**
 929          * Fetch revision comment if it's available to the specified audience.
 930          * If the specified audience does not have access to the comment, an
 931          * empty string will be returned.
 932          *
 933          * @param int $audience One of:
 934          *   Revision::FOR_PUBLIC       to be displayed to all users
 935          *   Revision::FOR_THIS_USER    to be displayed to the given user
 936          *   Revision::RAW              get the text regardless of permissions
 937          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 938          *   to the $audience parameter
 939          * @return string
 940          */
 941         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 942                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 943                         return '';
 944                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 945                         return '';
 946                 } else {
 947                         return $this->mComment;
 948                 }
 949         }
 950
 951         /**
 952          * Fetch revision comment without regard for the current user's permissions
 953          *
 954          * @return string
 955          * @deprecated since 1.25, use getComment( Revision::RAW )
 956          */
 957         public function getRawComment() {
 958                 wfDeprecated( __METHOD__, '1.25' );
 959                 return $this->getComment( self::RAW );
 960         }
 961
 962         /**
 963          * @return bool
 964          */
 965         public function isMinor() {
 966                 return (bool)$this->mMinorEdit;
 967         }
 968
 969         /**
 970          * @return int Rcid of the unpatrolled row, zero if there isn't one
 971          */
 972         public function isUnpatrolled() {
 973                 if ( $this->mUnpatrolled !== null ) {
 974                         return $this->mUnpatrolled;
 975                 }
 976                 $rc = $this->getRecentChange();
 977                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 978                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 979                 } else {
 980                         $this->mUnpatrolled = 0;
 981                 }
 982                 return $this->mUnpatrolled;
 983         }
 984
 985         /**
 986          * Get the RC object belonging to the current revision, if there's one
 987          *
 988          * @param int $flags (optional) $flags include:
 989          *      Revision::READ_LATEST  : Select the data from the master
 990          *
 991          * @since 1.22
 992          * @return RecentChange|null
 993          */
 994         public function getRecentChange( $flags = 0 ) {
 995                 $dbr = wfGetDB( DB_REPLICA );
 996
 997                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
 998
 999                 return RecentChange::newFromConds(
1000                         [
1001                                 'rc_user_text' => $this->getUserText( Revision::RAW ),
1002                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
1003                                 'rc_this_oldid' => $this->getId()
1004                         ],
1005                         __METHOD__,
1006                         $dbType
1007                 );
1008         }
1009
1010         /**
1011          * @param int $field One of DELETED_* bitfield constants
1012          *
1013          * @return bool
1014          */
1015         public function isDeleted( $field ) {
1016                 if ( $this->isCurrent() && $field === self::DELETED_TEXT ) {
1017                         // Current revisions of pages cannot have the content hidden. Skipping this
1018                         // check is very useful for Parser as it fetches templates using newKnownCurrent().
1019                         // Calling getVisibility() in that case triggers a verification database query.
1020                         return false; // no need to check
1021                 }
1022
1023                 return ( $this->getVisibility() & $field ) == $field;
1024         }
1025
1026         /**
1027          * Get the deletion bitfield of the revision
1028          *
1029          * @return int
1030          */
1031         public function getVisibility() {
1032                 $this->loadMutableFields();
1033
1034                 return (int)$this->mDeleted;
1035         }
1036
1037         /**
1038          * Fetch revision text if it's available to the specified audience.
1039          * If the specified audience does not have the ability to view this
1040          * revision, an empty string will be returned.
1041          *
1042          * @param int $audience One of:
1043          *   Revision::FOR_PUBLIC       to be displayed to all users
1044          *   Revision::FOR_THIS_USER    to be displayed to the given user
1045          *   Revision::RAW              get the text regardless of permissions
1046          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1047          *   to the $audience parameter
1048          *
1049          * @deprecated since 1.21, use getContent() instead
1050          * @return string
1051          */
1052         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
1053                 wfDeprecated( __METHOD__, '1.21' );
1054
1055                 $content = $this->getContent( $audience, $user );
1056                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
1057         }
1058
1059         /**
1060          * Fetch revision content if it's available to the specified audience.
1061          * If the specified audience does not have the ability to view this
1062          * revision, null will be returned.
1063          *
1064          * @param int $audience One of:
1065          *   Revision::FOR_PUBLIC       to be displayed to all users
1066          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1067          *   Revision::RAW              get the text regardless of permissions
1068          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1069          *   to the $audience parameter
1070          * @since 1.21
1071          * @return Content|null
1072          */
1073         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1074                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1075                         return null;
1076                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1077                         return null;
1078                 } else {
1079                         return $this->getContentInternal();
1080                 }
1081         }
1082
1083         /**
1084          * Get original serialized data (without checking view restrictions)
1085          *
1086          * @since 1.21
1087          * @return string
1088          */
1089         public function getSerializedData() {
1090                 if ( $this->mText === null ) {
1091                         // Revision is immutable. Load on demand.
1092                         $this->mText = $this->loadText();
1093                 }
1094
1095                 return $this->mText;
1096         }
1097
1098         /**
1099          * Gets the content object for the revision (or null on failure).
1100          *
1101          * Note that for mutable Content objects, each call to this method will return a
1102          * fresh clone.
1103          *
1104          * @since 1.21
1105          * @return Content|null The Revision's content, or null on failure.
1106          */
1107         protected function getContentInternal() {
1108                 if ( $this->mContent === null ) {
1109                         $text = $this->getSerializedData();
1110
1111                         if ( $text !== null && $text !== false ) {
1112                                 // Unserialize content
1113                                 $handler = $this->getContentHandler();
1114                                 $format = $this->getContentFormat();
1115
1116                                 $this->mContent = $handler->unserializeContent( $text, $format );
1117                         }
1118                 }
1119
1120                 // NOTE: copy() will return $this for immutable content objects
1121                 return $this->mContent ? $this->mContent->copy() : null;
1122         }
1123
1124         /**
1125          * Returns the content model for this revision.
1126          *
1127          * If no content model was stored in the database, the default content model for the title is
1128          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1129          * is used as a last resort.
1130          *
1131          * @return string The content model id associated with this revision,
1132          *     see the CONTENT_MODEL_XXX constants.
1133          **/
1134         public function getContentModel() {
1135                 if ( !$this->mContentModel ) {
1136                         $title = $this->getTitle();
1137                         if ( $title ) {
1138                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1139                         } else {
1140                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1141                         }
1142
1143                         assert( !empty( $this->mContentModel ) );
1144                 }
1145
1146                 return $this->mContentModel;
1147         }
1148
1149         /**
1150          * Returns the content format for this revision.
1151          *
1152          * If no content format was stored in the database, the default format for this
1153          * revision's content model is returned.
1154          *
1155          * @return string The content format id associated with this revision,
1156          *     see the CONTENT_FORMAT_XXX constants.
1157          **/
1158         public function getContentFormat() {
1159                 if ( !$this->mContentFormat ) {
1160                         $handler = $this->getContentHandler();
1161                         $this->mContentFormat = $handler->getDefaultFormat();
1162
1163                         assert( !empty( $this->mContentFormat ) );
1164                 }
1165
1166                 return $this->mContentFormat;
1167         }
1168
1169         /**
1170          * Returns the content handler appropriate for this revision's content model.
1171          *
1172          * @throws MWException
1173          * @return ContentHandler
1174          */
1175         public function getContentHandler() {
1176                 if ( !$this->mContentHandler ) {
1177                         $model = $this->getContentModel();
1178                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1179
1180                         $format = $this->getContentFormat();
1181
1182                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1183                                 throw new MWException( "Oops, the content format $format is not supported for "
1184                                         . "this content model, $model" );
1185                         }
1186                 }
1187
1188                 return $this->mContentHandler;
1189         }
1190
1191         /**
1192          * @return string
1193          */
1194         public function getTimestamp() {
1195                 return wfTimestamp( TS_MW, $this->mTimestamp );
1196         }
1197
1198         /**
1199          * @return bool
1200          */
1201         public function isCurrent() {
1202                 return $this->mCurrent;
1203         }
1204
1205         /**
1206          * Get previous revision for this title
1207          *
1208          * @return Revision|null
1209          */
1210         public function getPrevious() {
1211                 if ( $this->getTitle() ) {
1212                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1213                         if ( $prev ) {
1214                                 return self::newFromTitle( $this->getTitle(), $prev );
1215                         }
1216                 }
1217                 return null;
1218         }
1219
1220         /**
1221          * Get next revision for this title
1222          *
1223          * @return Revision|null
1224          */
1225         public function getNext() {
1226                 if ( $this->getTitle() ) {
1227                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1228                         if ( $next ) {
1229                                 return self::newFromTitle( $this->getTitle(), $next );
1230                         }
1231                 }
1232                 return null;
1233         }
1234
1235         /**
1236          * Get previous revision Id for this page_id
1237          * This is used to populate rev_parent_id on save
1238          *
1239          * @param IDatabase $db
1240          * @return int
1241          */
1242         private function getPreviousRevisionId( $db ) {
1243                 if ( $this->mPage === null ) {
1244                         return 0;
1245                 }
1246                 # Use page_latest if ID is not given
1247                 if ( !$this->mId ) {
1248                         $prevId = $db->selectField( 'page', 'page_latest',
1249                                 [ 'page_id' => $this->mPage ],
1250                                 __METHOD__ );
1251                 } else {
1252                         $prevId = $db->selectField( 'revision', 'rev_id',
1253                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1254                                 __METHOD__,
1255                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1256                 }
1257                 return intval( $prevId );
1258         }
1259
1260         /**
1261          * Get revision text associated with an old or archive row
1262          * $row is usually an object from wfFetchRow(), both the flags and the text
1263          * field must be included.
1264          *
1265          * @param stdClass $row The text data
1266          * @param string $prefix Table prefix (default 'old_')
1267          * @param string|bool $wiki The name of the wiki to load the revision text from
1268          *   (same as the the wiki $row was loaded from) or false to indicate the local
1269          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1270          *   identifier as understood by the LoadBalancer class.
1271          * @return string Text the text requested or false on failure
1272          */
1273         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1274
1275                 # Get data
1276                 $textField = $prefix . 'text';
1277                 $flagsField = $prefix . 'flags';
1278
1279                 if ( isset( $row->$flagsField ) ) {
1280                         $flags = explode( ',', $row->$flagsField );
1281                 } else {
1282                         $flags = [];
1283                 }
1284
1285                 if ( isset( $row->$textField ) ) {
1286                         $text = $row->$textField;
1287                 } else {
1288                         return false;
1289                 }
1290
1291                 # Use external methods for external objects, text in table is URL-only then
1292                 if ( in_array( 'external', $flags ) ) {
1293                         $url = $text;
1294                         $parts = explode( '://', $url, 2 );
1295                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1296                                 return false;
1297                         }
1298                         $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1299                 }
1300
1301                 // If the text was fetched without an error, convert it
1302                 if ( $text !== false ) {
1303                         $text = self::decompressRevisionText( $text, $flags );
1304                 }
1305                 return $text;
1306         }
1307
1308         /**
1309          * If $wgCompressRevisions is enabled, we will compress data.
1310          * The input string is modified in place.
1311          * Return value is the flags field: contains 'gzip' if the
1312          * data is compressed, and 'utf-8' if we're saving in UTF-8
1313          * mode.
1314          *
1315          * @param mixed $text Reference to a text
1316          * @return string
1317          */
1318         public static function compressRevisionText( &$text ) {
1319                 global $wgCompressRevisions;
1320                 $flags = [];
1321
1322                 # Revisions not marked this way will be converted
1323                 # on load if $wgLegacyCharset is set in the future.
1324                 $flags[] = 'utf-8';
1325
1326                 if ( $wgCompressRevisions ) {
1327                         if ( function_exists( 'gzdeflate' ) ) {
1328                                 $deflated = gzdeflate( $text );
1329
1330                                 if ( $deflated === false ) {
1331                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1332                                 } else {
1333                                         $text = $deflated;
1334                                         $flags[] = 'gzip';
1335                                 }
1336                         } else {
1337                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1338                         }
1339                 }
1340                 return implode( ',', $flags );
1341         }
1342
1343         /**
1344          * Re-converts revision text according to it's flags.
1345          *
1346          * @param mixed $text Reference to a text
1347          * @param array $flags Compression flags
1348          * @return string|bool Decompressed text, or false on failure
1349          */
1350         public static function decompressRevisionText( $text, $flags ) {
1351                 if ( in_array( 'gzip', $flags ) ) {
1352                         # Deal with optional compression of archived pages.
1353                         # This can be done periodically via maintenance/compressOld.php, and
1354                         # as pages are saved if $wgCompressRevisions is set.
1355                         $text = gzinflate( $text );
1356
1357                         if ( $text === false ) {
1358                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1359                                 return false;
1360                         }
1361                 }
1362
1363                 if ( in_array( 'object', $flags ) ) {
1364                         # Generic compressed storage
1365                         $obj = unserialize( $text );
1366                         if ( !is_object( $obj ) ) {
1367                                 // Invalid object
1368                                 return false;
1369                         }
1370                         $text = $obj->getText();
1371                 }
1372
1373                 global $wgLegacyEncoding;
1374                 if ( $text !== false && $wgLegacyEncoding
1375                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1376                 ) {
1377                         # Old revisions kept around in a legacy encoding?
1378                         # Upconvert on demand.
1379                         # ("utf8" checked for compatibility with some broken
1380                         #  conversion scripts 2008-12-30)
1381                         global $wgContLang;
1382                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1383                 }
1384
1385                 return $text;
1386         }
1387
1388         /**
1389          * Insert a new revision into the database, returning the new revision ID
1390          * number on success and dies horribly on failure.
1391          *
1392          * @param IDatabase $dbw (master connection)
1393          * @throws MWException
1394          * @return int
1395          */
1396         public function insertOn( $dbw ) {
1397                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1398
1399                 // We're inserting a new revision, so we have to use master anyway.
1400                 // If it's a null revision, it may have references to rows that
1401                 // are not in the replica yet (the text row).
1402                 $this->mQueryFlags |= self::READ_LATEST;
1403
1404                 // Not allowed to have rev_page equal to 0, false, etc.
1405                 if ( !$this->mPage ) {
1406                         $title = $this->getTitle();
1407                         if ( $title instanceof Title ) {
1408                                 $titleText = ' for page ' . $title->getPrefixedText();
1409                         } else {
1410                                 $titleText = '';
1411                         }
1412                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1413                 }
1414
1415                 $this->checkContentModel();
1416
1417                 $data = $this->mText;
1418                 $flags = self::compressRevisionText( $data );
1419
1420                 # Write to external storage if required
1421                 if ( $wgDefaultExternalStore ) {
1422                         // Store and get the URL
1423                         $data = ExternalStore::insertToDefault( $data );
1424                         if ( !$data ) {
1425                                 throw new MWException( "Unable to store text to external storage" );
1426                         }
1427                         if ( $flags ) {
1428                                 $flags .= ',';
1429                         }
1430                         $flags .= 'external';
1431                 }
1432
1433                 # Record the text (or external storage URL) to the text table
1434                 if ( $this->mTextId === null ) {
1435                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1436                         $dbw->insert( 'text',
1437                                 [
1438                                         'old_id' => $old_id,
1439                                         'old_text' => $data,
1440                                         'old_flags' => $flags,
1441                                 ], __METHOD__
1442                         );
1443                         $this->mTextId = $dbw->insertId();
1444                 }
1445
1446                 if ( $this->mComment === null ) {
1447                         $this->mComment = "";
1448                 }
1449
1450                 # Record the edit in revisions
1451                 $rev_id = $this->mId !== null
1452                         ? $this->mId
1453                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1454                 $row = [
1455                         'rev_id'         => $rev_id,
1456                         'rev_page'       => $this->mPage,
1457                         'rev_text_id'    => $this->mTextId,
1458                         'rev_comment'    => $this->mComment,
1459                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1460                         'rev_user'       => $this->mUser,
1461                         'rev_user_text'  => $this->mUserText,
1462                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1463                         'rev_deleted'    => $this->mDeleted,
1464                         'rev_len'        => $this->mSize,
1465                         'rev_parent_id'  => $this->mParentId === null
1466                                 ? $this->getPreviousRevisionId( $dbw )
1467                                 : $this->mParentId,
1468                         'rev_sha1'       => $this->mSha1 === null
1469                                 ? Revision::base36Sha1( $this->mText )
1470                                 : $this->mSha1,
1471                 ];
1472
1473                 if ( $wgContentHandlerUseDB ) {
1474                         // NOTE: Store null for the default model and format, to save space.
1475                         // XXX: Makes the DB sensitive to changed defaults.
1476                         // Make this behavior optional? Only in miser mode?
1477
1478                         $model = $this->getContentModel();
1479                         $format = $this->getContentFormat();
1480
1481                         $title = $this->getTitle();
1482
1483                         if ( $title === null ) {
1484                                 throw new MWException( "Insufficient information to determine the title of the "
1485                                         . "revision's page!" );
1486                         }
1487
1488                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1489                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1490
1491                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1492                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1493                 }
1494
1495                 $dbw->insert( 'revision', $row, __METHOD__ );
1496
1497                 $this->mId = $rev_id !== null ? $rev_id : $dbw->insertId();
1498
1499                 // Assertion to try to catch T92046
1500                 if ( (int)$this->mId === 0 ) {
1501                         throw new UnexpectedValueException(
1502                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1503                                         var_export( $row, 1 )
1504                         );
1505                 }
1506
1507                 Hooks::run( 'RevisionInsertComplete', [ &$this, $data, $flags ] );
1508
1509                 return $this->mId;
1510         }
1511
1512         protected function checkContentModel() {
1513                 global $wgContentHandlerUseDB;
1514
1515                 // Note: may return null for revisions that have not yet been inserted
1516                 $title = $this->getTitle();
1517
1518                 $model = $this->getContentModel();
1519                 $format = $this->getContentFormat();
1520                 $handler = $this->getContentHandler();
1521
1522                 if ( !$handler->isSupportedFormat( $format ) ) {
1523                         $t = $title->getPrefixedDBkey();
1524
1525                         throw new MWException( "Can't use format $format with content model $model on $t" );
1526                 }
1527
1528                 if ( !$wgContentHandlerUseDB && $title ) {
1529                         // if $wgContentHandlerUseDB is not set,
1530                         // all revisions must use the default content model and format.
1531
1532                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1533                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1534                         $defaultFormat = $defaultHandler->getDefaultFormat();
1535
1536                         if ( $this->getContentModel() != $defaultModel ) {
1537                                 $t = $title->getPrefixedDBkey();
1538
1539                                 throw new MWException( "Can't save non-default content model with "
1540                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1541                                         . "default for $t is $defaultModel" );
1542                         }
1543
1544                         if ( $this->getContentFormat() != $defaultFormat ) {
1545                                 $t = $title->getPrefixedDBkey();
1546
1547                                 throw new MWException( "Can't use non-default content format with "
1548                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1549                                         . "default for $t is $defaultFormat" );
1550                         }
1551                 }
1552
1553                 $content = $this->getContent( Revision::RAW );
1554                 $prefixedDBkey = $title->getPrefixedDBkey();
1555                 $revId = $this->mId;
1556
1557                 if ( !$content ) {
1558                         throw new MWException(
1559                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1560                         );
1561                 }
1562                 if ( !$content->isValid() ) {
1563                         throw new MWException(
1564                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1565                         );
1566                 }
1567         }
1568
1569         /**
1570          * Get the base 36 SHA-1 value for a string of text
1571          * @param string $text
1572          * @return string
1573          */
1574         public static function base36Sha1( $text ) {
1575                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1576         }
1577
1578         /**
1579          * Lazy-load the revision's text.
1580          * Currently hardcoded to the 'text' table storage engine.
1581          *
1582          * @return string|bool The revision's text, or false on failure
1583          */
1584         private function loadText() {
1585                 global $wgRevisionCacheExpiry;
1586
1587                 $cache = ObjectCache::getMainWANInstance();
1588                 if ( $cache->getQoS( $cache::ATTR_EMULATION ) <= $cache::QOS_EMULATION_SQL ) {
1589                         // Do not cache RDBMs blobs in...the RDBMs store
1590                         $ttl = $cache::TTL_UNCACHEABLE;
1591                 } else {
1592                         $ttl = $wgRevisionCacheExpiry ?: $cache::TTL_UNCACHEABLE;
1593                 }
1594
1595                 // No negative caching; negative hits on text rows may be due to corrupted replica DBs
1596                 return $cache->getWithSetCallback(
1597                         $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
1598                         $ttl,
1599                         function () {
1600                                 return $this->fetchText();
1601                         },
1602                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1603                 );
1604         }
1605
1606         private function fetchText() {
1607                 $textId = $this->getTextId();
1608
1609                 // If we kept data for lazy extraction, use it now...
1610                 if ( $this->mTextRow !== null ) {
1611                         $row = $this->mTextRow;
1612                         $this->mTextRow = null;
1613                 } else {
1614                         $row = null;
1615                 }
1616
1617                 // Callers doing updates will pass in READ_LATEST as usual. Since the text/blob tables
1618                 // do not normally get rows changed around, set READ_LATEST_IMMUTABLE in those cases.
1619                 $flags = $this->mQueryFlags;
1620                 $flags |= DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST )
1621                         ? self::READ_LATEST_IMMUTABLE
1622                         : 0;
1623
1624                 list( $index, $options, $fallbackIndex, $fallbackOptions ) =
1625                         DBAccessObjectUtils::getDBOptions( $flags );
1626
1627                 if ( !$row ) {
1628                         // Text data is immutable; check replica DBs first.
1629                         $row = wfGetDB( $index )->selectRow(
1630                                 'text',
1631                                 [ 'old_text', 'old_flags' ],
1632                                 [ 'old_id' => $textId ],
1633                                 __METHOD__,
1634                                 $options
1635                         );
1636                 }
1637
1638                 // Fallback to DB_MASTER in some cases if the row was not found
1639                 if ( !$row && $fallbackIndex !== null ) {
1640                         // Use FOR UPDATE if it was used to fetch this revision. This avoids missing the row
1641                         // due to REPEATABLE-READ. Also fallback to the master if READ_LATEST is provided.
1642                         $row = wfGetDB( $fallbackIndex )->selectRow(
1643                                 'text',
1644                                 [ 'old_text', 'old_flags' ],
1645                                 [ 'old_id' => $textId ],
1646                                 __METHOD__,
1647                                 $fallbackOptions
1648                         );
1649                 }
1650
1651                 if ( !$row ) {
1652                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1653                 }
1654
1655                 $text = self::getRevisionText( $row );
1656                 if ( $row && $text === false ) {
1657                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1658                 }
1659
1660                 return is_string( $text ) ? $text : false;
1661         }
1662
1663         /**
1664          * Create a new null-revision for insertion into a page's
1665          * history. This will not re-save the text, but simply refer
1666          * to the text from the previous version.
1667          *
1668          * Such revisions can for instance identify page rename
1669          * operations and other such meta-modifications.
1670          *
1671          * @param IDatabase $dbw
1672          * @param int $pageId ID number of the page to read from
1673          * @param string $summary Revision's summary
1674          * @param bool $minor Whether the revision should be considered as minor
1675          * @param User|null $user User object to use or null for $wgUser
1676          * @return Revision|null Revision or null on error
1677          */
1678         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1679                 global $wgContentHandlerUseDB, $wgContLang;
1680
1681                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1682                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1683
1684                 if ( $wgContentHandlerUseDB ) {
1685                         $fields[] = 'rev_content_model';
1686                         $fields[] = 'rev_content_format';
1687                 }
1688
1689                 $current = $dbw->selectRow(
1690                         [ 'page', 'revision' ],
1691                         $fields,
1692                         [
1693                                 'page_id' => $pageId,
1694                                 'page_latest=rev_id',
1695                         ],
1696                         __METHOD__,
1697                         [ 'FOR UPDATE' ] // T51581
1698                 );
1699
1700                 if ( $current ) {
1701                         if ( !$user ) {
1702                                 global $wgUser;
1703                                 $user = $wgUser;
1704                         }
1705
1706                         // Truncate for whole multibyte characters
1707                         $summary = $wgContLang->truncate( $summary, 255 );
1708
1709                         $row = [
1710                                 'page'       => $pageId,
1711                                 'user_text'  => $user->getName(),
1712                                 'user'       => $user->getId(),
1713                                 'comment'    => $summary,
1714                                 'minor_edit' => $minor,
1715                                 'text_id'    => $current->rev_text_id,
1716                                 'parent_id'  => $current->page_latest,
1717                                 'len'        => $current->rev_len,
1718                                 'sha1'       => $current->rev_sha1
1719                         ];
1720
1721                         if ( $wgContentHandlerUseDB ) {
1722                                 $row['content_model'] = $current->rev_content_model;
1723                                 $row['content_format'] = $current->rev_content_format;
1724                         }
1725
1726                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1727
1728                         $revision = new Revision( $row );
1729                 } else {
1730                         $revision = null;
1731                 }
1732
1733                 return $revision;
1734         }
1735
1736         /**
1737          * Determine if the current user is allowed to view a particular
1738          * field of this revision, if it's marked as deleted.
1739          *
1740          * @param int $field One of self::DELETED_TEXT,
1741          *                              self::DELETED_COMMENT,
1742          *                              self::DELETED_USER
1743          * @param User|null $user User object to check, or null to use $wgUser
1744          * @return bool
1745          */
1746         public function userCan( $field, User $user = null ) {
1747                 return self::userCanBitfield( $this->getVisibility(), $field, $user );
1748         }
1749
1750         /**
1751          * Determine if the current user is allowed to view a particular
1752          * field of this revision, if it's marked as deleted. This is used
1753          * by various classes to avoid duplication.
1754          *
1755          * @param int $bitfield Current field
1756          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1757          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1758          *                               self::DELETED_USER = File::DELETED_USER
1759          * @param User|null $user User object to check, or null to use $wgUser
1760          * @param Title|null $title A Title object to check for per-page restrictions on,
1761          *                          instead of just plain userrights
1762          * @return bool
1763          */
1764         public static function userCanBitfield( $bitfield, $field, User $user = null,
1765                 Title $title = null
1766         ) {
1767                 if ( $bitfield & $field ) { // aspect is deleted
1768                         if ( $user === null ) {
1769                                 global $wgUser;
1770                                 $user = $wgUser;
1771                         }
1772                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1773                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1774                         } elseif ( $field & self::DELETED_TEXT ) {
1775                                 $permissions = [ 'deletedtext' ];
1776                         } else {
1777                                 $permissions = [ 'deletedhistory' ];
1778                         }
1779                         $permissionlist = implode( ', ', $permissions );
1780                         if ( $title === null ) {
1781                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1782                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1783                         } else {
1784                                 $text = $title->getPrefixedText();
1785                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1786                                 foreach ( $permissions as $perm ) {
1787                                         if ( $title->userCan( $perm, $user ) ) {
1788                                                 return true;
1789                                         }
1790                                 }
1791                                 return false;
1792                         }
1793                 } else {
1794                         return true;
1795                 }
1796         }
1797
1798         /**
1799          * Get rev_timestamp from rev_id, without loading the rest of the row
1800          *
1801          * @param Title $title
1802          * @param int $id
1803          * @return string|bool False if not found
1804          */
1805         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1806                 $db = ( $flags & self::READ_LATEST )
1807                         ? wfGetDB( DB_MASTER )
1808                         : wfGetDB( DB_REPLICA );
1809                 // Casting fix for databases that can't take '' for rev_id
1810                 if ( $id == '' ) {
1811                         $id = 0;
1812                 }
1813                 $conds = [ 'rev_id' => $id ];
1814                 $conds['rev_page'] = $title->getArticleID();
1815                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1816
1817                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
1818         }
1819
1820         /**
1821          * Get count of revisions per page...not very efficient
1822          *
1823          * @param IDatabase $db
1824          * @param int $id Page id
1825          * @return int
1826          */
1827         static function countByPageId( $db, $id ) {
1828                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
1829                         [ 'rev_page' => $id ], __METHOD__ );
1830                 if ( $row ) {
1831                         return $row->revCount;
1832                 }
1833                 return 0;
1834         }
1835
1836         /**
1837          * Get count of revisions per page...not very efficient
1838          *
1839          * @param IDatabase $db
1840          * @param Title $title
1841          * @return int
1842          */
1843         static function countByTitle( $db, $title ) {
1844                 $id = $title->getArticleID();
1845                 if ( $id ) {
1846                         return self::countByPageId( $db, $id );
1847                 }
1848                 return 0;
1849         }
1850
1851         /**
1852          * Check if no edits were made by other users since
1853          * the time a user started editing the page. Limit to
1854          * 50 revisions for the sake of performance.
1855          *
1856          * @since 1.20
1857          * @deprecated since 1.24
1858          *
1859          * @param IDatabase|int $db The Database to perform the check on. May be given as a
1860          *        Database object or a database identifier usable with wfGetDB.
1861          * @param int $pageId The ID of the page in question
1862          * @param int $userId The ID of the user in question
1863          * @param string $since Look at edits since this time
1864          *
1865          * @return bool True if the given user was the only one to edit since the given timestamp
1866          */
1867         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1868                 if ( !$userId ) {
1869                         return false;
1870                 }
1871
1872                 if ( is_int( $db ) ) {
1873                         $db = wfGetDB( $db );
1874                 }
1875
1876                 $res = $db->select( 'revision',
1877                         'rev_user',
1878                         [
1879                                 'rev_page' => $pageId,
1880                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1881                         ],
1882                         __METHOD__,
1883                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
1884                 foreach ( $res as $row ) {
1885                         if ( $row->rev_user != $userId ) {
1886                                 return false;
1887                         }
1888                 }
1889                 return true;
1890         }
1891
1892         /**
1893          * Load a revision based on a known page ID and current revision ID from the DB
1894          *
1895          * This method allows for the use of caching, though accessing anything that normally
1896          * requires permission checks (aside from the text) will trigger a small DB lookup.
1897          * The title will also be lazy loaded, though setTitle() can be used to preload it.
1898          *
1899          * @param IDatabase $db
1900          * @param int $pageId Page ID
1901          * @param int $revId Known current revision of this page
1902          * @return Revision|bool Returns false if missing
1903          * @since 1.28
1904          */
1905         public static function newKnownCurrent( IDatabase $db, $pageId, $revId ) {
1906                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1907                 return $cache->getWithSetCallback(
1908                         // Page/rev IDs passed in from DB to reflect history merges
1909                         $cache->makeGlobalKey( 'revision', $db->getWikiID(), $pageId, $revId ),
1910                         $cache::TTL_WEEK,
1911                         function ( $curValue, &$ttl, array &$setOpts ) use ( $db, $pageId, $revId ) {
1912                                 $setOpts += Database::getCacheSetOptions( $db );
1913
1914                                 $rev = Revision::loadFromPageId( $db, $pageId, $revId );
1915                                 // Reflect revision deletion and user renames
1916                                 if ( $rev ) {
1917                                         $rev->mTitle = null; // mutable; lazy-load
1918                                         $rev->mRefreshMutableFields = true;
1919                                 }
1920
1921                                 return $rev ?: false; // don't cache negatives
1922                         }
1923                 );
1924         }
1925
1926         /**
1927          * For cached revisions, make sure the user name and rev_deleted is up-to-date
1928          */
1929         private function loadMutableFields() {
1930                 if ( !$this->mRefreshMutableFields ) {
1931                         return; // not needed
1932                 }
1933
1934                 $this->mRefreshMutableFields = false;
1935                 $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
1936                 $row = $dbr->selectRow(
1937                         [ 'revision', 'user' ],
1938                         [ 'rev_deleted', 'user_name' ],
1939                         [ 'rev_id' => $this->mId, 'user_id = rev_user' ],
1940                         __METHOD__
1941                 );
1942                 if ( $row ) { // update values
1943                         $this->mDeleted = (int)$row->rev_deleted;
1944                         $this->mUserText = $row->user_name;
1945                 }
1946         }
1947 }