includes/Revision.php

   1 <?php
   2 /**
   3  * Representation of a page version.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 use Wikimedia\Rdbms\Database;
  24 use Wikimedia\Rdbms\IDatabase;
  25 use MediaWiki\Linker\LinkTarget;
  26 use MediaWiki\MediaWikiServices;
  27 use Wikimedia\Rdbms\ResultWrapper;
  28 use Wikimedia\Rdbms\FakeResultWrapper;
  29
  30 /**
  31  * @todo document
  32  */
  33 class Revision implements IDBAccessObject {
  34         /** @var int|null */
  35         protected $mId;
  36         /** @var int|null */
  37         protected $mPage;
  38         /** @var string */
  39         protected $mUserText;
  40         /** @var string */
  41         protected $mOrigUserText;
  42         /** @var int */
  43         protected $mUser;
  44         /** @var bool */
  45         protected $mMinorEdit;
  46         /** @var string */
  47         protected $mTimestamp;
  48         /** @var int */
  49         protected $mDeleted;
  50         /** @var int */
  51         protected $mSize;
  52         /** @var string */
  53         protected $mSha1;
  54         /** @var int */
  55         protected $mParentId;
  56         /** @var string */
  57         protected $mComment;
  58         /** @var string */
  59         protected $mText;
  60         /** @var int */
  61         protected $mTextId;
  62         /** @var int */
  63         protected $mUnpatrolled;
  64
  65         /** @var stdClass|null */
  66         protected $mTextRow;
  67
  68         /**  @var null|Title */
  69         protected $mTitle;
  70         /** @var bool */
  71         protected $mCurrent;
  72         /** @var string */
  73         protected $mContentModel;
  74         /** @var string */
  75         protected $mContentFormat;
  76
  77         /** @var Content|null|bool */
  78         protected $mContent;
  79         /** @var null|ContentHandler */
  80         protected $mContentHandler;
  81
  82         /** @var int */
  83         protected $mQueryFlags = 0;
  84         /** @var bool Used for cached values to reload user text and rev_deleted */
  85         protected $mRefreshMutableFields = false;
  86         /** @var string Wiki ID; false means the current wiki */
  87         protected $mWiki = false;
  88
  89         // Revision deletion constants
  90         const DELETED_TEXT = 1;
  91         const DELETED_COMMENT = 2;
  92         const DELETED_USER = 4;
  93         const DELETED_RESTRICTED = 8;
  94         const SUPPRESSED_USER = 12; // convenience
  95         const SUPPRESSED_ALL = 15; // convenience
  96
  97         // Audience options for accessors
  98         const FOR_PUBLIC = 1;
  99         const FOR_THIS_USER = 2;
 100         const RAW = 3;
 101
 102         const TEXT_CACHE_GROUP = 'revisiontext:10'; // process cache name and max key count
 103
 104         /**
 105          * Load a page revision from a given revision ID number.
 106          * Returns null if no such revision can be found.
 107          *
 108          * $flags include:
 109          *      Revision::READ_LATEST  : Select the data from the master
 110          *      Revision::READ_LOCKING : Select & lock the data from the master
 111          *
 112          * @param int $id
 113          * @param int $flags (optional)
 114          * @return Revision|null
 115          */
 116         public static function newFromId( $id, $flags = 0 ) {
 117                 return self::newFromConds( [ 'rev_id' => intval( $id ) ], $flags );
 118         }
 119
 120         /**
 121          * Load either the current, or a specified, revision
 122          * that's attached to a given link target. If not attached
 123          * to that link target, will return null.
 124          *
 125          * $flags include:
 126          *      Revision::READ_LATEST  : Select the data from the master
 127          *      Revision::READ_LOCKING : Select & lock the data from the master
 128          *
 129          * @param LinkTarget $linkTarget
 130          * @param int $id (optional)
 131          * @param int $flags Bitfield (optional)
 132          * @return Revision|null
 133          */
 134         public static function newFromTitle( LinkTarget $linkTarget, $id = 0, $flags = 0 ) {
 135                 $conds = [
 136                         'page_namespace' => $linkTarget->getNamespace(),
 137                         'page_title' => $linkTarget->getDBkey()
 138                 ];
 139                 if ( $id ) {
 140                         // Use the specified ID
 141                         $conds['rev_id'] = $id;
 142                         return self::newFromConds( $conds, $flags );
 143                 } else {
 144                         // Use a join to get the latest revision
 145                         $conds[] = 'rev_id=page_latest';
 146                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 147                         return self::loadFromConds( $db, $conds, $flags );
 148                 }
 149         }
 150
 151         /**
 152          * Load either the current, or a specified, revision
 153          * that's attached to a given page ID.
 154          * Returns null if no such revision can be found.
 155          *
 156          * $flags include:
 157          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 158          *      Revision::READ_LOCKING : Select & lock the data from the master
 159          *
 160          * @param int $pageId
 161          * @param int $revId (optional)
 162          * @param int $flags Bitfield (optional)
 163          * @return Revision|null
 164          */
 165         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 166                 $conds = [ 'page_id' => $pageId ];
 167                 if ( $revId ) {
 168                         $conds['rev_id'] = $revId;
 169                         return self::newFromConds( $conds, $flags );
 170                 } else {
 171                         // Use a join to get the latest revision
 172                         $conds[] = 'rev_id = page_latest';
 173                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 174                         return self::loadFromConds( $db, $conds, $flags );
 175                 }
 176         }
 177
 178         /**
 179          * Make a fake revision object from an archive table row. This is queried
 180          * for permissions or even inserted (as in Special:Undelete)
 181          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 182          *
 183          * @param object $row
 184          * @param array $overrides
 185          *
 186          * @throws MWException
 187          * @return Revision
 188          */
 189         public static function newFromArchiveRow( $row, $overrides = [] ) {
 190                 global $wgContentHandlerUseDB;
 191
 192                 $attribs = $overrides + [
 193                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 194                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 195                         'comment'    => CommentStore::newKey( 'ar_comment' )
 196                                 // Legacy because $row may have come from self::selectArchiveFields()
 197                                 ->getCommentLegacy( wfGetDB( DB_REPLICA ), $row, true )->text,
 198                         'user'       => $row->ar_user,
 199                         'user_text'  => $row->ar_user_text,
 200                         'timestamp'  => $row->ar_timestamp,
 201                         'minor_edit' => $row->ar_minor_edit,
 202                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 203                         'deleted'    => $row->ar_deleted,
 204                         'len'        => $row->ar_len,
 205                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 206                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 207                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 208                 ];
 209
 210                 if ( !$wgContentHandlerUseDB ) {
 211                         unset( $attribs['content_model'] );
 212                         unset( $attribs['content_format'] );
 213                 }
 214
 215                 if ( !isset( $attribs['title'] )
 216                         && isset( $row->ar_namespace )
 217                         && isset( $row->ar_title )
 218                 ) {
 219                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 220                 }
 221
 222                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 223                         // Pre-1.5 ar_text row
 224                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 225                         if ( $attribs['text'] === false ) {
 226                                 throw new MWException( 'Unable to load text from archive row (possibly T24624)' );
 227                         }
 228                 }
 229                 return new self( $attribs );
 230         }
 231
 232         /**
 233          * @since 1.19
 234          *
 235          * @param object $row
 236          * @return Revision
 237          */
 238         public static function newFromRow( $row ) {
 239                 return new self( $row );
 240         }
 241
 242         /**
 243          * Load a page revision from a given revision ID number.
 244          * Returns null if no such revision can be found.
 245          *
 246          * @param IDatabase $db
 247          * @param int $id
 248          * @return Revision|null
 249          */
 250         public static function loadFromId( $db, $id ) {
 251                 return self::loadFromConds( $db, [ 'rev_id' => intval( $id ) ] );
 252         }
 253
 254         /**
 255          * Load either the current, or a specified, revision
 256          * that's attached to a given page. If not attached
 257          * to that page, will return null.
 258          *
 259          * @param IDatabase $db
 260          * @param int $pageid
 261          * @param int $id
 262          * @return Revision|null
 263          */
 264         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 265                 $conds = [ 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) ];
 266                 if ( $id ) {
 267                         $conds['rev_id'] = intval( $id );
 268                 } else {
 269                         $conds[] = 'rev_id=page_latest';
 270                 }
 271                 return self::loadFromConds( $db, $conds );
 272         }
 273
 274         /**
 275          * Load either the current, or a specified, revision
 276          * that's attached to a given page. If not attached
 277          * to that page, will return null.
 278          *
 279          * @param IDatabase $db
 280          * @param Title $title
 281          * @param int $id
 282          * @return Revision|null
 283          */
 284         public static function loadFromTitle( $db, $title, $id = 0 ) {
 285                 if ( $id ) {
 286                         $matchId = intval( $id );
 287                 } else {
 288                         $matchId = 'page_latest';
 289                 }
 290                 return self::loadFromConds( $db,
 291                         [
 292                                 "rev_id=$matchId",
 293                                 'page_namespace' => $title->getNamespace(),
 294                                 'page_title' => $title->getDBkey()
 295                         ]
 296                 );
 297         }
 298
 299         /**
 300          * Load the revision for the given title with the given timestamp.
 301          * WARNING: Timestamps may in some circumstances not be unique,
 302          * so this isn't the best key to use.
 303          *
 304          * @param IDatabase $db
 305          * @param Title $title
 306          * @param string $timestamp
 307          * @return Revision|null
 308          */
 309         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 310                 return self::loadFromConds( $db,
 311                         [
 312                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 313                                 'page_namespace' => $title->getNamespace(),
 314                                 'page_title' => $title->getDBkey()
 315                         ]
 316                 );
 317         }
 318
 319         /**
 320          * Given a set of conditions, fetch a revision
 321          *
 322          * This method is used then a revision ID is qualified and
 323          * will incorporate some basic replica DB/master fallback logic
 324          *
 325          * @param array $conditions
 326          * @param int $flags (optional)
 327          * @return Revision|null
 328          */
 329         private static function newFromConds( $conditions, $flags = 0 ) {
 330                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 331
 332                 $rev = self::loadFromConds( $db, $conditions, $flags );
 333                 // Make sure new pending/committed revision are visibile later on
 334                 // within web requests to certain avoid bugs like T93866 and T94407.
 335                 if ( !$rev
 336                         && !( $flags & self::READ_LATEST )
 337                         && wfGetLB()->getServerCount() > 1
 338                         && wfGetLB()->hasOrMadeRecentMasterChanges()
 339                 ) {
 340                         $flags = self::READ_LATEST;
 341                         $db = wfGetDB( DB_MASTER );
 342                         $rev = self::loadFromConds( $db, $conditions, $flags );
 343                 }
 344
 345                 if ( $rev ) {
 346                         $rev->mQueryFlags = $flags;
 347                 }
 348
 349                 return $rev;
 350         }
 351
 352         /**
 353          * Given a set of conditions, fetch a revision from
 354          * the given database connection.
 355          *
 356          * @param IDatabase $db
 357          * @param array $conditions
 358          * @param int $flags (optional)
 359          * @return Revision|null
 360          */
 361         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 362                 $row = self::fetchFromConds( $db, $conditions, $flags );
 363                 if ( $row ) {
 364                         $rev = new Revision( $row );
 365                         $rev->mWiki = $db->getDomainID();
 366
 367                         return $rev;
 368                 }
 369
 370                 return null;
 371         }
 372
 373         /**
 374          * Return a wrapper for a series of database rows to
 375          * fetch all of a given page's revisions in turn.
 376          * Each row can be fed to the constructor to get objects.
 377          *
 378          * @param LinkTarget $title
 379          * @return ResultWrapper
 380          * @deprecated Since 1.28
 381          */
 382         public static function fetchRevision( LinkTarget $title ) {
 383                 $row = self::fetchFromConds(
 384                         wfGetDB( DB_REPLICA ),
 385                         [
 386                                 'rev_id=page_latest',
 387                                 'page_namespace' => $title->getNamespace(),
 388                                 'page_title' => $title->getDBkey()
 389                         ]
 390                 );
 391
 392                 return new FakeResultWrapper( $row ? [ $row ] : [] );
 393         }
 394
 395         /**
 396          * Given a set of conditions, return a ResultWrapper
 397          * which will return matching database rows with the
 398          * fields necessary to build Revision objects.
 399          *
 400          * @param IDatabase $db
 401          * @param array $conditions
 402          * @param int $flags (optional)
 403          * @return stdClass
 404          */
 405         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 406                 $revQuery = self::getQueryInfo( [ 'page', 'user' ] );
 407                 $options = [];
 408                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 409                         $options[] = 'FOR UPDATE';
 410                 }
 411                 return $db->selectRow(
 412                         $revQuery['tables'],
 413                         $revQuery['fields'],
 414                         $conditions,
 415                         __METHOD__,
 416                         $options,
 417                         $revQuery['joins']
 418                 );
 419         }
 420
 421         /**
 422          * Return the value of a select() JOIN conds array for the user table.
 423          * This will get user table rows for logged-in users.
 424          * @since 1.19
 425          * @deprecated since 1.31, use self::getQueryInfo( [ 'user' ] ) instead.
 426          * @return array
 427          */
 428         public static function userJoinCond() {
 429                 wfDeprecated( __METHOD__, '1.31' );
 430                 return [ 'LEFT JOIN', [ 'rev_user != 0', 'user_id = rev_user' ] ];
 431         }
 432
 433         /**
 434          * Return the value of a select() page conds array for the page table.
 435          * This will assure that the revision(s) are not orphaned from live pages.
 436          * @since 1.19
 437          * @deprecated since 1.31, use self::getQueryInfo( [ 'page' ] ) instead.
 438          * @return array
 439          */
 440         public static function pageJoinCond() {
 441                 wfDeprecated( __METHOD__, '1.31' );
 442                 return [ 'INNER JOIN', [ 'page_id = rev_page' ] ];
 443         }
 444
 445         /**
 446          * Return the list of revision fields that should be selected to create
 447          * a new revision.
 448          * @deprecated since 1.31, use self::getQueryInfo() instead.
 449          * @return array
 450          */
 451         public static function selectFields() {
 452                 global $wgContentHandlerUseDB;
 453
 454                 wfDeprecated( __METHOD__, '1.31' );
 455
 456                 $fields = [
 457                         'rev_id',
 458                         'rev_page',
 459                         'rev_text_id',
 460                         'rev_timestamp',
 461                         'rev_user_text',
 462                         'rev_user',
 463                         'rev_minor_edit',
 464                         'rev_deleted',
 465                         'rev_len',
 466                         'rev_parent_id',
 467                         'rev_sha1',
 468                 ];
 469
 470                 $fields += CommentStore::newKey( 'rev_comment' )->getFields();
 471
 472                 if ( $wgContentHandlerUseDB ) {
 473                         $fields[] = 'rev_content_format';
 474                         $fields[] = 'rev_content_model';
 475                 }
 476
 477                 return $fields;
 478         }
 479
 480         /**
 481          * Return the list of revision fields that should be selected to create
 482          * a new revision from an archive row.
 483          * @deprecated since 1.31, use self::getArchiveQueryInfo() instead.
 484          * @return array
 485          */
 486         public static function selectArchiveFields() {
 487                 global $wgContentHandlerUseDB;
 488
 489                 wfDeprecated( __METHOD__, '1.31' );
 490
 491                 $fields = [
 492                         'ar_id',
 493                         'ar_page_id',
 494                         'ar_rev_id',
 495                         'ar_text',
 496                         'ar_text_id',
 497                         'ar_timestamp',
 498                         'ar_user_text',
 499                         'ar_user',
 500                         'ar_minor_edit',
 501                         'ar_deleted',
 502                         'ar_len',
 503                         'ar_parent_id',
 504                         'ar_sha1',
 505                 ];
 506
 507                 $fields += CommentStore::newKey( 'ar_comment' )->getFields();
 508
 509                 if ( $wgContentHandlerUseDB ) {
 510                         $fields[] = 'ar_content_format';
 511                         $fields[] = 'ar_content_model';
 512                 }
 513                 return $fields;
 514         }
 515
 516         /**
 517          * Return the list of text fields that should be selected to read the
 518          * revision text
 519          * @deprecated since 1.31, use self::getQueryInfo( [ 'text' ] ) instead.
 520          * @return array
 521          */
 522         public static function selectTextFields() {
 523                 wfDeprecated( __METHOD__, '1.31' );
 524                 return [
 525                         'old_text',
 526                         'old_flags'
 527                 ];
 528         }
 529
 530         /**
 531          * Return the list of page fields that should be selected from page table
 532          * @deprecated since 1.31, use self::getQueryInfo( [ 'page' ] ) instead.
 533          * @return array
 534          */
 535         public static function selectPageFields() {
 536                 wfDeprecated( __METHOD__, '1.31' );
 537                 return [
 538                         'page_namespace',
 539                         'page_title',
 540                         'page_id',
 541                         'page_latest',
 542                         'page_is_redirect',
 543                         'page_len',
 544                 ];
 545         }
 546
 547         /**
 548          * Return the list of user fields that should be selected from user table
 549          * @deprecated since 1.31, use self::getQueryInfo( [ 'user' ] ) instead.
 550          * @return array
 551          */
 552         public static function selectUserFields() {
 553                 wfDeprecated( __METHOD__, '1.31' );
 554                 return [ 'user_name' ];
 555         }
 556
 557         /**
 558          * Return the tables, fields, and join conditions to be selected to create
 559          * a new revision object.
 560          * @since 1.31
 561          * @param array $options Any combination of the following strings
 562          *  - 'page': Join with the page table, and select fields to identify the page
 563          *  - 'user': Join with the user table, and select the user name
 564          *  - 'text': Join with the text table, and select fields to load page text
 565          * @return array With three keys:
 566          *   - tables: (string[]) to include in the `$table` to `IDatabase->select()`
 567          *   - fields: (string[]) to include in the `$vars` to `IDatabase->select()`
 568          *   - joins: (array) to include in the `$join_conds` to `IDatabase->select()`
 569          */
 570         public static function getQueryInfo( $options = [] ) {
 571                 global $wgContentHandlerUseDB;
 572
 573                 $commentQuery = CommentStore::newKey( 'rev_comment' )->getJoin();
 574                 $ret = [
 575                         'tables' => [ 'revision' ] + $commentQuery['tables'],
 576                         'fields' => [
 577                                 'rev_id',
 578                                 'rev_page',
 579                                 'rev_text_id',
 580                                 'rev_timestamp',
 581                                 'rev_user_text',
 582                                 'rev_user',
 583                                 'rev_minor_edit',
 584                                 'rev_deleted',
 585                                 'rev_len',
 586                                 'rev_parent_id',
 587                                 'rev_sha1',
 588                         ] + $commentQuery['fields'],
 589                         'joins' => $commentQuery['joins'],
 590                 ];
 591
 592                 if ( $wgContentHandlerUseDB ) {
 593                         $ret['fields'][] = 'rev_content_format';
 594                         $ret['fields'][] = 'rev_content_model';
 595                 }
 596
 597                 if ( in_array( 'page', $options, true ) ) {
 598                         $ret['tables'][] = 'page';
 599                         $ret['fields'] = array_merge( $ret['fields'], [
 600                                 'page_namespace',
 601                                 'page_title',
 602                                 'page_id',
 603                                 'page_latest',
 604                                 'page_is_redirect',
 605                                 'page_len',
 606                         ] );
 607                         $ret['joins']['page'] = [ 'INNER JOIN', [ 'page_id = rev_page' ] ];
 608                 }
 609
 610                 if ( in_array( 'user', $options, true ) ) {
 611                         $ret['tables'][] = 'user';
 612                         $ret['fields'] = array_merge( $ret['fields'], [
 613                                 'user_name',
 614                         ] );
 615                         $ret['joins']['user'] = [ 'LEFT JOIN', [ 'rev_user != 0', 'user_id = rev_user' ] ];
 616                 }
 617
 618                 if ( in_array( 'text', $options, true ) ) {
 619                         $ret['tables'][] = 'text';
 620                         $ret['fields'] = array_merge( $ret['fields'], [
 621                                 'old_text',
 622                                 'old_flags'
 623                         ] );
 624                         $ret['joins']['text'] = [ 'INNER JOIN', [ 'rev_text_id=old_id' ] ];
 625                 }
 626
 627                 return $ret;
 628         }
 629
 630         /**
 631          * Return the tables, fields, and join conditions to be selected to create
 632          * a new archived revision object.
 633          * @since 1.31
 634          * @return array With three keys:
 635          *   - tables: (string[]) to include in the `$table` to `IDatabase->select()`
 636          *   - fields: (string[]) to include in the `$vars` to `IDatabase->select()`
 637          *   - joins: (array) to include in the `$join_conds` to `IDatabase->select()`
 638          */
 639         public static function getArchiveQueryInfo() {
 640                 global $wgContentHandlerUseDB;
 641
 642                 $commentQuery = CommentStore::newKey( 'ar_comment' )->getJoin();
 643                 $ret = [
 644                         'tables' => [ 'archive' ] + $commentQuery['tables'],
 645                         'fields' => [
 646                                 'ar_id',
 647                                 'ar_page_id',
 648                                 'ar_rev_id',
 649                                 'ar_text',
 650                                 'ar_text_id',
 651                                 'ar_timestamp',
 652                                 'ar_user_text',
 653                                 'ar_user',
 654                                 'ar_minor_edit',
 655                                 'ar_deleted',
 656                                 'ar_len',
 657                                 'ar_parent_id',
 658                                 'ar_sha1',
 659                         ] + $commentQuery['fields'],
 660                         'joins' => $commentQuery['joins'],
 661                 ];
 662
 663                 if ( $wgContentHandlerUseDB ) {
 664                         $ret['fields'][] = 'ar_content_format';
 665                         $ret['fields'][] = 'ar_content_model';
 666                 }
 667
 668                 return $ret;
 669         }
 670
 671         /**
 672          * Do a batched query to get the parent revision lengths
 673          * @param IDatabase $db
 674          * @param array $revIds
 675          * @return array
 676          */
 677         public static function getParentLengths( $db, array $revIds ) {
 678                 $revLens = [];
 679                 if ( !$revIds ) {
 680                         return $revLens; // empty
 681                 }
 682                 $res = $db->select( 'revision',
 683                         [ 'rev_id', 'rev_len' ],
 684                         [ 'rev_id' => $revIds ],
 685                         __METHOD__ );
 686                 foreach ( $res as $row ) {
 687                         $revLens[$row->rev_id] = $row->rev_len;
 688                 }
 689                 return $revLens;
 690         }
 691
 692         /**
 693          * @param object|array $row Either a database row or an array
 694          * @throws MWException
 695          * @access private
 696          */
 697         public function __construct( $row ) {
 698                 if ( is_object( $row ) ) {
 699                         $this->constructFromDbRowObject( $row );
 700                 } elseif ( is_array( $row ) ) {
 701                         $this->constructFromRowArray( $row );
 702                 } else {
 703                         throw new MWException( 'Revision constructor passed invalid row format.' );
 704                 }
 705                 $this->mUnpatrolled = null;
 706         }
 707
 708         /**
 709          * @param object $row
 710          */
 711         private function constructFromDbRowObject( $row ) {
 712                 $this->mId = intval( $row->rev_id );
 713                 $this->mPage = intval( $row->rev_page );
 714                 $this->mTextId = intval( $row->rev_text_id );
 715                 $this->mComment = CommentStore::newKey( 'rev_comment' )
 716                         // Legacy because $row may have come from self::selectFields()
 717                         ->getCommentLegacy( wfGetDB( DB_REPLICA ), $row, true )->text;
 718                 $this->mUser = intval( $row->rev_user );
 719                 $this->mMinorEdit = intval( $row->rev_minor_edit );
 720                 $this->mTimestamp = $row->rev_timestamp;
 721                 $this->mDeleted = intval( $row->rev_deleted );
 722
 723                 if ( !isset( $row->rev_parent_id ) ) {
 724                         $this->mParentId = null;
 725                 } else {
 726                         $this->mParentId = intval( $row->rev_parent_id );
 727                 }
 728
 729                 if ( !isset( $row->rev_len ) ) {
 730                         $this->mSize = null;
 731                 } else {
 732                         $this->mSize = intval( $row->rev_len );
 733                 }
 734
 735                 if ( !isset( $row->rev_sha1 ) ) {
 736                         $this->mSha1 = null;
 737                 } else {
 738                         $this->mSha1 = $row->rev_sha1;
 739                 }
 740
 741                 if ( isset( $row->page_latest ) ) {
 742                         $this->mCurrent = ( $row->rev_id == $row->page_latest );
 743                         $this->mTitle = Title::newFromRow( $row );
 744                 } else {
 745                         $this->mCurrent = false;
 746                         $this->mTitle = null;
 747                 }
 748
 749                 if ( !isset( $row->rev_content_model ) ) {
 750                         $this->mContentModel = null; # determine on demand if needed
 751                 } else {
 752                         $this->mContentModel = strval( $row->rev_content_model );
 753                 }
 754
 755                 if ( !isset( $row->rev_content_format ) ) {
 756                         $this->mContentFormat = null; # determine on demand if needed
 757                 } else {
 758                         $this->mContentFormat = strval( $row->rev_content_format );
 759                 }
 760
 761                 // Lazy extraction...
 762                 $this->mText = null;
 763                 if ( isset( $row->old_text ) ) {
 764                         $this->mTextRow = $row;
 765                 } else {
 766                         // 'text' table row entry will be lazy-loaded
 767                         $this->mTextRow = null;
 768                 }
 769
 770                 // Use user_name for users and rev_user_text for IPs...
 771                 $this->mUserText = null; // lazy load if left null
 772                 if ( $this->mUser == 0 ) {
 773                         $this->mUserText = $row->rev_user_text; // IP user
 774                 } elseif ( isset( $row->user_name ) ) {
 775                         $this->mUserText = $row->user_name; // logged-in user
 776                 }
 777                 $this->mOrigUserText = $row->rev_user_text;
 778         }
 779
 780         /**
 781          * @param array $row
 782          *
 783          * @throws MWException
 784          */
 785         private function constructFromRowArray( array $row ) {
 786                 // Build a new revision to be saved...
 787                 global $wgUser; // ugh
 788
 789                 # if we have a content object, use it to set the model and type
 790                 if ( !empty( $row['content'] ) ) {
 791                         if ( !( $row['content'] instanceof Content ) ) {
 792                                 throw new MWException( '`content` field must contain a Content object.' );
 793                         }
 794
 795                         // @todo when is that set? test with external store setup! check out insertOn() [dk]
 796                         if ( !empty( $row['text_id'] ) ) {
 797                                 throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 798                                         "can't serialize content object" );
 799                         }
 800
 801                         $row['content_model'] = $row['content']->getModel();
 802                         # note: mContentFormat is initializes later accordingly
 803                         # note: content is serialized later in this method!
 804                         # also set text to null?
 805                 }
 806
 807                 $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 808                 $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 809                 $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 810                 $this->mUserText = isset( $row['user_text'] )
 811                         ? strval( $row['user_text'] ) : $wgUser->getName();
 812                 $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 813                 $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 814                 $this->mTimestamp = isset( $row['timestamp'] )
 815                         ? strval( $row['timestamp'] ) : wfTimestampNow();
 816                 $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 817                 $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 818                 $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 819                 $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 820
 821                 $this->mContentModel = isset( $row['content_model'] )
 822                         ? strval( $row['content_model'] ) : null;
 823                 $this->mContentFormat = isset( $row['content_format'] )
 824                         ? strval( $row['content_format'] ) : null;
 825
 826                 // Enforce spacing trimming on supplied text
 827                 $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 828                 $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 829                 $this->mTextRow = null;
 830
 831                 $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 832
 833                 // if we have a Content object, override mText and mContentModel
 834                 if ( !empty( $row['content'] ) ) {
 835                         $handler = $this->getContentHandler();
 836                         $this->mContent = $row['content'];
 837
 838                         $this->mContentModel = $this->mContent->getModel();
 839                         $this->mContentHandler = null;
 840
 841                         $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 842                 } elseif ( $this->mText !== null ) {
 843                         $handler = $this->getContentHandler();
 844                         $this->mContent = $handler->unserializeContent( $this->mText );
 845                 }
 846
 847                 // If we have a Title object, make sure it is consistent with mPage.
 848                 if ( $this->mTitle && $this->mTitle->exists() ) {
 849                         if ( $this->mPage === null ) {
 850                                 // if the page ID wasn't known, set it now
 851                                 $this->mPage = $this->mTitle->getArticleID();
 852                         } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 853                                 // Got different page IDs. This may be legit (e.g. during undeletion),
 854                                 // but it seems worth mentioning it in the log.
 855                                 wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 856                                         $this->mTitle->getArticleID() . " provided by the Title object." );
 857                         }
 858                 }
 859
 860                 $this->mCurrent = false;
 861
 862                 // If we still have no length, see it we have the text to figure it out
 863                 if ( !$this->mSize && $this->mContent !== null ) {
 864                         $this->mSize = $this->mContent->getSize();
 865                 }
 866
 867                 // Same for sha1
 868                 if ( $this->mSha1 === null ) {
 869                         $this->mSha1 = $this->mText === null ? null : self::base36Sha1( $this->mText );
 870                 }
 871
 872                 // force lazy init
 873                 $this->getContentModel();
 874                 $this->getContentFormat();
 875         }
 876
 877         /**
 878          * Get revision ID
 879          *
 880          * @return int|null
 881          */
 882         public function getId() {
 883                 return $this->mId;
 884         }
 885
 886         /**
 887          * Set the revision ID
 888          *
 889          * This should only be used for proposed revisions that turn out to be null edits
 890          *
 891          * @since 1.19
 892          * @param int $id
 893          */
 894         public function setId( $id ) {
 895                 $this->mId = (int)$id;
 896         }
 897
 898         /**
 899          * Set the user ID/name
 900          *
 901          * This should only be used for proposed revisions that turn out to be null edits
 902          *
 903          * @since 1.28
 904          * @deprecated since 1.31, please reuse old Revision object
 905          * @param int $id User ID
 906          * @param string $name User name
 907          */
 908         public function setUserIdAndName( $id, $name ) {
 909                 $this->mUser = (int)$id;
 910                 $this->mUserText = $name;
 911                 $this->mOrigUserText = $name;
 912         }
 913
 914         /**
 915          * Get text row ID
 916          *
 917          * @return int|null
 918          */
 919         public function getTextId() {
 920                 return $this->mTextId;
 921         }
 922
 923         /**
 924          * Get parent revision ID (the original previous page revision)
 925          *
 926          * @return int|null
 927          */
 928         public function getParentId() {
 929                 return $this->mParentId;
 930         }
 931
 932         /**
 933          * Returns the length of the text in this revision, or null if unknown.
 934          *
 935          * @return int|null
 936          */
 937         public function getSize() {
 938                 return $this->mSize;
 939         }
 940
 941         /**
 942          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 943          *
 944          * @return string|null
 945          */
 946         public function getSha1() {
 947                 return $this->mSha1;
 948         }
 949
 950         /**
 951          * Returns the title of the page associated with this entry or null.
 952          *
 953          * Will do a query, when title is not set and id is given.
 954          *
 955          * @return Title|null
 956          */
 957         public function getTitle() {
 958                 if ( $this->mTitle !== null ) {
 959                         return $this->mTitle;
 960                 }
 961                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 962                 if ( $this->mId !== null ) {
 963                         $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
 964                         // @todo: Title::getSelectFields(), or Title::getQueryInfo(), or something like that
 965                         $row = $dbr->selectRow(
 966                                 [ 'revision', 'page' ],
 967                                 [
 968                                         'page_namespace',
 969                                         'page_title',
 970                                         'page_id',
 971                                         'page_latest',
 972                                         'page_is_redirect',
 973                                         'page_len',
 974                                 ],
 975                                 [ 'rev_id' => $this->mId ],
 976                                 __METHOD__,
 977                                 [],
 978                                 [ 'page' => [ 'JOIN', 'page_id=rev_page' ] ]
 979                         );
 980                         if ( $row ) {
 981                                 // @TODO: better foreign title handling
 982                                 $this->mTitle = Title::newFromRow( $row );
 983                         }
 984                 }
 985
 986                 if ( $this->mWiki === false || $this->mWiki === wfWikiID() ) {
 987                         // Loading by ID is best, though not possible for foreign titles
 988                         if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 989                                 $this->mTitle = Title::newFromID( $this->mPage );
 990                         }
 991                 }
 992
 993                 return $this->mTitle;
 994         }
 995
 996         /**
 997          * Set the title of the revision
 998          *
 999          * @param Title $title
1000          */
1001         public function setTitle( $title ) {
1002                 $this->mTitle = $title;
1003         }
1004
1005         /**
1006          * Get the page ID
1007          *
1008          * @return int|null
1009          */
1010         public function getPage() {
1011                 return $this->mPage;
1012         }
1013
1014         /**
1015          * Fetch revision's user id if it's available to the specified audience.
1016          * If the specified audience does not have access to it, zero will be
1017          * returned.
1018          *
1019          * @param int $audience One of:
1020          *   Revision::FOR_PUBLIC       to be displayed to all users
1021          *   Revision::FOR_THIS_USER    to be displayed to the given user
1022          *   Revision::RAW              get the ID regardless of permissions
1023          * @param User|null $user User object to check for, only if FOR_THIS_USER is passed
1024          *   to the $audience parameter
1025          * @return int
1026          */
1027         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
1028                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
1029                         return 0;
1030                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
1031                         return 0;
1032                 } else {
1033                         return $this->mUser;
1034                 }
1035         }
1036
1037         /**
1038          * Fetch revision's user id without regard for the current user's permissions
1039          *
1040          * @return int
1041          * @deprecated since 1.25, use getUser( Revision::RAW )
1042          */
1043         public function getRawUser() {
1044                 wfDeprecated( __METHOD__, '1.25' );
1045                 return $this->getUser( self::RAW );
1046         }
1047
1048         /**
1049          * Fetch revision's username if it's available to the specified audience.
1050          * If the specified audience does not have access to the username, an
1051          * empty string will be returned.
1052          *
1053          * @param int $audience One of:
1054          *   Revision::FOR_PUBLIC       to be displayed to all users
1055          *   Revision::FOR_THIS_USER    to be displayed to the given user
1056          *   Revision::RAW              get the text regardless of permissions
1057          * @param User|null $user User object to check for, only if FOR_THIS_USER is passed
1058          *   to the $audience parameter
1059          * @return string
1060          */
1061         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
1062                 $this->loadMutableFields();
1063
1064                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
1065                         return '';
1066                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
1067                         return '';
1068                 } else {
1069                         if ( $this->mUserText === null ) {
1070                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
1071                                 if ( $this->mUserText === false ) {
1072                                         # This shouldn't happen, but it can if the wiki was recovered
1073                                         # via importing revs and there is no user table entry yet.
1074                                         $this->mUserText = $this->mOrigUserText;
1075                                 }
1076                         }
1077                         return $this->mUserText;
1078                 }
1079         }
1080
1081         /**
1082          * Fetch revision's username without regard for view restrictions
1083          *
1084          * @return string
1085          * @deprecated since 1.25, use getUserText( Revision::RAW )
1086          */
1087         public function getRawUserText() {
1088                 wfDeprecated( __METHOD__, '1.25' );
1089                 return $this->getUserText( self::RAW );
1090         }
1091
1092         /**
1093          * Fetch revision comment if it's available to the specified audience.
1094          * If the specified audience does not have access to the comment, an
1095          * empty string will be returned.
1096          *
1097          * @param int $audience One of:
1098          *   Revision::FOR_PUBLIC       to be displayed to all users
1099          *   Revision::FOR_THIS_USER    to be displayed to the given user
1100          *   Revision::RAW              get the text regardless of permissions
1101          * @param User|null $user User object to check for, only if FOR_THIS_USER is passed
1102          *   to the $audience parameter
1103          * @return string
1104          */
1105         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
1106                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
1107                         return '';
1108                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
1109                         return '';
1110                 } else {
1111                         return $this->mComment;
1112                 }
1113         }
1114
1115         /**
1116          * Fetch revision comment without regard for the current user's permissions
1117          *
1118          * @return string
1119          * @deprecated since 1.25, use getComment( Revision::RAW )
1120          */
1121         public function getRawComment() {
1122                 wfDeprecated( __METHOD__, '1.25' );
1123                 return $this->getComment( self::RAW );
1124         }
1125
1126         /**
1127          * @return bool
1128          */
1129         public function isMinor() {
1130                 return (bool)$this->mMinorEdit;
1131         }
1132
1133         /**
1134          * @return int Rcid of the unpatrolled row, zero if there isn't one
1135          */
1136         public function isUnpatrolled() {
1137                 if ( $this->mUnpatrolled !== null ) {
1138                         return $this->mUnpatrolled;
1139                 }
1140                 $rc = $this->getRecentChange();
1141                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
1142                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
1143                 } else {
1144                         $this->mUnpatrolled = 0;
1145                 }
1146                 return $this->mUnpatrolled;
1147         }
1148
1149         /**
1150          * Get the RC object belonging to the current revision, if there's one
1151          *
1152          * @param int $flags (optional) $flags include:
1153          *      Revision::READ_LATEST  : Select the data from the master
1154          *
1155          * @since 1.22
1156          * @return RecentChange|null
1157          */
1158         public function getRecentChange( $flags = 0 ) {
1159                 $dbr = wfGetDB( DB_REPLICA );
1160
1161                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
1162
1163                 return RecentChange::newFromConds(
1164                         [
1165                                 'rc_user_text' => $this->getUserText( self::RAW ),
1166                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
1167                                 'rc_this_oldid' => $this->getId()
1168                         ],
1169                         __METHOD__,
1170                         $dbType
1171                 );
1172         }
1173
1174         /**
1175          * @param int $field One of DELETED_* bitfield constants
1176          *
1177          * @return bool
1178          */
1179         public function isDeleted( $field ) {
1180                 if ( $this->isCurrent() && $field === self::DELETED_TEXT ) {
1181                         // Current revisions of pages cannot have the content hidden. Skipping this
1182                         // check is very useful for Parser as it fetches templates using newKnownCurrent().
1183                         // Calling getVisibility() in that case triggers a verification database query.
1184                         return false; // no need to check
1185                 }
1186
1187                 return ( $this->getVisibility() & $field ) == $field;
1188         }
1189
1190         /**
1191          * Get the deletion bitfield of the revision
1192          *
1193          * @return int
1194          */
1195         public function getVisibility() {
1196                 $this->loadMutableFields();
1197
1198                 return (int)$this->mDeleted;
1199         }
1200
1201         /**
1202          * Fetch revision content if it's available to the specified audience.
1203          * If the specified audience does not have the ability to view this
1204          * revision, null will be returned.
1205          *
1206          * @param int $audience One of:
1207          *   Revision::FOR_PUBLIC       to be displayed to all users
1208          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1209          *   Revision::RAW              get the text regardless of permissions
1210          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1211          *   to the $audience parameter
1212          * @since 1.21
1213          * @return Content|null
1214          */
1215         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1216                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1217                         return null;
1218                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1219                         return null;
1220                 } else {
1221                         return $this->getContentInternal();
1222                 }
1223         }
1224
1225         /**
1226          * Get original serialized data (without checking view restrictions)
1227          *
1228          * @since 1.21
1229          * @return string
1230          */
1231         public function getSerializedData() {
1232                 if ( $this->mText === null ) {
1233                         // Revision is immutable. Load on demand.
1234                         $this->mText = $this->loadText();
1235                 }
1236
1237                 return $this->mText;
1238         }
1239
1240         /**
1241          * Gets the content object for the revision (or null on failure).
1242          *
1243          * Note that for mutable Content objects, each call to this method will return a
1244          * fresh clone.
1245          *
1246          * @since 1.21
1247          * @return Content|null The Revision's content, or null on failure.
1248          */
1249         protected function getContentInternal() {
1250                 if ( $this->mContent === null ) {
1251                         $text = $this->getSerializedData();
1252
1253                         if ( $text !== null && $text !== false ) {
1254                                 // Unserialize content
1255                                 $handler = $this->getContentHandler();
1256                                 $format = $this->getContentFormat();
1257
1258                                 $this->mContent = $handler->unserializeContent( $text, $format );
1259                         }
1260                 }
1261
1262                 // NOTE: copy() will return $this for immutable content objects
1263                 return $this->mContent ? $this->mContent->copy() : null;
1264         }
1265
1266         /**
1267          * Returns the content model for this revision.
1268          *
1269          * If no content model was stored in the database, the default content model for the title is
1270          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1271          * is used as a last resort.
1272          *
1273          * @return string The content model id associated with this revision,
1274          *     see the CONTENT_MODEL_XXX constants.
1275          */
1276         public function getContentModel() {
1277                 if ( !$this->mContentModel ) {
1278                         $title = $this->getTitle();
1279                         if ( $title ) {
1280                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1281                         } else {
1282                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1283                         }
1284
1285                         assert( !empty( $this->mContentModel ) );
1286                 }
1287
1288                 return $this->mContentModel;
1289         }
1290
1291         /**
1292          * Returns the content format for this revision.
1293          *
1294          * If no content format was stored in the database, the default format for this
1295          * revision's content model is returned.
1296          *
1297          * @return string The content format id associated with this revision,
1298          *     see the CONTENT_FORMAT_XXX constants.
1299          */
1300         public function getContentFormat() {
1301                 if ( !$this->mContentFormat ) {
1302                         $handler = $this->getContentHandler();
1303                         $this->mContentFormat = $handler->getDefaultFormat();
1304
1305                         assert( !empty( $this->mContentFormat ) );
1306                 }
1307
1308                 return $this->mContentFormat;
1309         }
1310
1311         /**
1312          * Returns the content handler appropriate for this revision's content model.
1313          *
1314          * @throws MWException
1315          * @return ContentHandler
1316          */
1317         public function getContentHandler() {
1318                 if ( !$this->mContentHandler ) {
1319                         $model = $this->getContentModel();
1320                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1321
1322                         $format = $this->getContentFormat();
1323
1324                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1325                                 throw new MWException( "Oops, the content format $format is not supported for "
1326                                         . "this content model, $model" );
1327                         }
1328                 }
1329
1330                 return $this->mContentHandler;
1331         }
1332
1333         /**
1334          * @return string
1335          */
1336         public function getTimestamp() {
1337                 return wfTimestamp( TS_MW, $this->mTimestamp );
1338         }
1339
1340         /**
1341          * @return bool
1342          */
1343         public function isCurrent() {
1344                 return $this->mCurrent;
1345         }
1346
1347         /**
1348          * Get previous revision for this title
1349          *
1350          * @return Revision|null
1351          */
1352         public function getPrevious() {
1353                 if ( $this->getTitle() ) {
1354                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1355                         if ( $prev ) {
1356                                 return self::newFromTitle( $this->getTitle(), $prev );
1357                         }
1358                 }
1359                 return null;
1360         }
1361
1362         /**
1363          * Get next revision for this title
1364          *
1365          * @return Revision|null
1366          */
1367         public function getNext() {
1368                 if ( $this->getTitle() ) {
1369                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1370                         if ( $next ) {
1371                                 return self::newFromTitle( $this->getTitle(), $next );
1372                         }
1373                 }
1374                 return null;
1375         }
1376
1377         /**
1378          * Get previous revision Id for this page_id
1379          * This is used to populate rev_parent_id on save
1380          *
1381          * @param IDatabase $db
1382          * @return int
1383          */
1384         private function getPreviousRevisionId( $db ) {
1385                 if ( $this->mPage === null ) {
1386                         return 0;
1387                 }
1388                 # Use page_latest if ID is not given
1389                 if ( !$this->mId ) {
1390                         $prevId = $db->selectField( 'page', 'page_latest',
1391                                 [ 'page_id' => $this->mPage ],
1392                                 __METHOD__ );
1393                 } else {
1394                         $prevId = $db->selectField( 'revision', 'rev_id',
1395                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1396                                 __METHOD__,
1397                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1398                 }
1399                 return intval( $prevId );
1400         }
1401
1402         /**
1403          * Get revision text associated with an old or archive row
1404          *
1405          * Both the flags and the text field must be included. Including the old_id
1406          * field will activate cache usage as long as the $wiki parameter is not set.
1407          *
1408          * @param stdClass $row The text data
1409          * @param string $prefix Table prefix (default 'old_')
1410          * @param string|bool $wiki The name of the wiki to load the revision text from
1411          *   (same as the the wiki $row was loaded from) or false to indicate the local
1412          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1413          *   identifier as understood by the LoadBalancer class.
1414          * @return string|false Text the text requested or false on failure
1415          */
1416         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1417                 $textField = $prefix . 'text';
1418                 $flagsField = $prefix . 'flags';
1419
1420                 if ( isset( $row->$flagsField ) ) {
1421                         $flags = explode( ',', $row->$flagsField );
1422                 } else {
1423                         $flags = [];
1424                 }
1425
1426                 if ( isset( $row->$textField ) ) {
1427                         $text = $row->$textField;
1428                 } else {
1429                         return false;
1430                 }
1431
1432                 // Use external methods for external objects, text in table is URL-only then
1433                 if ( in_array( 'external', $flags ) ) {
1434                         $url = $text;
1435                         $parts = explode( '://', $url, 2 );
1436                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1437                                 return false;
1438                         }
1439
1440                         if ( isset( $row->old_id ) && $wiki === false ) {
1441                                 // Make use of the wiki-local revision text cache
1442                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1443                                 // The cached value should be decompressed, so handle that and return here
1444                                 return $cache->getWithSetCallback(
1445                                         $cache->makeKey( 'revisiontext', 'textid', $row->old_id ),
1446                                         self::getCacheTTL( $cache ),
1447                                         function () use ( $url, $wiki, $flags ) {
1448                                                 // No negative caching per Revision::loadText()
1449                                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1450
1451                                                 return self::decompressRevisionText( $text, $flags );
1452                                         },
1453                                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1454                                 );
1455                         } else {
1456                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1457                         }
1458                 }
1459
1460                 return self::decompressRevisionText( $text, $flags );
1461         }
1462
1463         /**
1464          * If $wgCompressRevisions is enabled, we will compress data.
1465          * The input string is modified in place.
1466          * Return value is the flags field: contains 'gzip' if the
1467          * data is compressed, and 'utf-8' if we're saving in UTF-8
1468          * mode.
1469          *
1470          * @param mixed &$text Reference to a text
1471          * @return string
1472          */
1473         public static function compressRevisionText( &$text ) {
1474                 global $wgCompressRevisions;
1475                 $flags = [];
1476
1477                 # Revisions not marked this way will be converted
1478                 # on load if $wgLegacyCharset is set in the future.
1479                 $flags[] = 'utf-8';
1480
1481                 if ( $wgCompressRevisions ) {
1482                         if ( function_exists( 'gzdeflate' ) ) {
1483                                 $deflated = gzdeflate( $text );
1484
1485                                 if ( $deflated === false ) {
1486                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1487                                 } else {
1488                                         $text = $deflated;
1489                                         $flags[] = 'gzip';
1490                                 }
1491                         } else {
1492                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1493                         }
1494                 }
1495                 return implode( ',', $flags );
1496         }
1497
1498         /**
1499          * Re-converts revision text according to it's flags.
1500          *
1501          * @param mixed $text Reference to a text
1502          * @param array $flags Compression flags
1503          * @return string|bool Decompressed text, or false on failure
1504          */
1505         public static function decompressRevisionText( $text, $flags ) {
1506                 global $wgLegacyEncoding, $wgContLang;
1507
1508                 if ( $text === false ) {
1509                         // Text failed to be fetched; nothing to do
1510                         return false;
1511                 }
1512
1513                 if ( in_array( 'gzip', $flags ) ) {
1514                         # Deal with optional compression of archived pages.
1515                         # This can be done periodically via maintenance/compressOld.php, and
1516                         # as pages are saved if $wgCompressRevisions is set.
1517                         $text = gzinflate( $text );
1518
1519                         if ( $text === false ) {
1520                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1521                                 return false;
1522                         }
1523                 }
1524
1525                 if ( in_array( 'object', $flags ) ) {
1526                         # Generic compressed storage
1527                         $obj = unserialize( $text );
1528                         if ( !is_object( $obj ) ) {
1529                                 // Invalid object
1530                                 return false;
1531                         }
1532                         $text = $obj->getText();
1533                 }
1534
1535                 if ( $text !== false && $wgLegacyEncoding
1536                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1537                 ) {
1538                         # Old revisions kept around in a legacy encoding?
1539                         # Upconvert on demand.
1540                         # ("utf8" checked for compatibility with some broken
1541                         #  conversion scripts 2008-12-30)
1542                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1543                 }
1544
1545                 return $text;
1546         }
1547
1548         /**
1549          * Insert a new revision into the database, returning the new revision ID
1550          * number on success and dies horribly on failure.
1551          *
1552          * @param IDatabase $dbw (master connection)
1553          * @throws MWException
1554          * @return int The revision ID
1555          */
1556         public function insertOn( $dbw ) {
1557                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1558
1559                 // We're inserting a new revision, so we have to use master anyway.
1560                 // If it's a null revision, it may have references to rows that
1561                 // are not in the replica yet (the text row).
1562                 $this->mQueryFlags |= self::READ_LATEST;
1563
1564                 // Not allowed to have rev_page equal to 0, false, etc.
1565                 if ( !$this->mPage ) {
1566                         $title = $this->getTitle();
1567                         if ( $title instanceof Title ) {
1568                                 $titleText = ' for page ' . $title->getPrefixedText();
1569                         } else {
1570                                 $titleText = '';
1571                         }
1572                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1573                 }
1574
1575                 $this->checkContentModel();
1576
1577                 $data = $this->mText;
1578                 $flags = self::compressRevisionText( $data );
1579
1580                 # Write to external storage if required
1581                 if ( $wgDefaultExternalStore ) {
1582                         // Store and get the URL
1583                         $data = ExternalStore::insertToDefault( $data );
1584                         if ( !$data ) {
1585                                 throw new MWException( "Unable to store text to external storage" );
1586                         }
1587                         if ( $flags ) {
1588                                 $flags .= ',';
1589                         }
1590                         $flags .= 'external';
1591                 }
1592
1593                 # Record the text (or external storage URL) to the text table
1594                 if ( $this->mTextId === null ) {
1595                         $dbw->insert( 'text',
1596                                 [
1597                                         'old_text' => $data,
1598                                         'old_flags' => $flags,
1599                                 ], __METHOD__
1600                         );
1601                         $this->mTextId = $dbw->insertId();
1602                 }
1603
1604                 if ( $this->mComment === null ) {
1605                         $this->mComment = "";
1606                 }
1607
1608                 # Record the edit in revisions
1609                 $row = [
1610                         'rev_page'       => $this->mPage,
1611                         'rev_text_id'    => $this->mTextId,
1612                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1613                         'rev_user'       => $this->mUser,
1614                         'rev_user_text'  => $this->mUserText,
1615                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1616                         'rev_deleted'    => $this->mDeleted,
1617                         'rev_len'        => $this->mSize,
1618                         'rev_parent_id'  => $this->mParentId === null
1619                                 ? $this->getPreviousRevisionId( $dbw )
1620                                 : $this->mParentId,
1621                         'rev_sha1'       => $this->mSha1 === null
1622                                 ? self::base36Sha1( $this->mText )
1623                                 : $this->mSha1,
1624                 ];
1625                 if ( $this->mId !== null ) {
1626                         $row['rev_id'] = $this->mId;
1627                 }
1628
1629                 list( $commentFields, $commentCallback ) =
1630                         CommentStore::newKey( 'rev_comment' )->insertWithTempTable( $dbw, $this->mComment );
1631                 $row += $commentFields;
1632
1633                 if ( $wgContentHandlerUseDB ) {
1634                         // NOTE: Store null for the default model and format, to save space.
1635                         // XXX: Makes the DB sensitive to changed defaults.
1636                         // Make this behavior optional? Only in miser mode?
1637
1638                         $model = $this->getContentModel();
1639                         $format = $this->getContentFormat();
1640
1641                         $title = $this->getTitle();
1642
1643                         if ( $title === null ) {
1644                                 throw new MWException( "Insufficient information to determine the title of the "
1645                                         . "revision's page!" );
1646                         }
1647
1648                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1649                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1650
1651                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1652                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1653                 }
1654
1655                 $dbw->insert( 'revision', $row, __METHOD__ );
1656
1657                 if ( $this->mId === null ) {
1658                         // Only if auto-increment was used
1659                         $this->mId = $dbw->insertId();
1660                 }
1661                 $commentCallback( $this->mId );
1662
1663                 // Assertion to try to catch T92046
1664                 if ( (int)$this->mId === 0 ) {
1665                         throw new UnexpectedValueException(
1666                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1667                                         var_export( $row, 1 )
1668                         );
1669                 }
1670
1671                 // Insert IP revision into ip_changes for use when querying for a range.
1672                 if ( $this->mUser === 0 && IP::isValid( $this->mUserText ) ) {
1673                         $ipcRow = [
1674                                 'ipc_rev_id'        => $this->mId,
1675                                 'ipc_rev_timestamp' => $row['rev_timestamp'],
1676                                 'ipc_hex'           => IP::toHex( $row['rev_user_text'] ),
1677                         ];
1678                         $dbw->insert( 'ip_changes', $ipcRow, __METHOD__ );
1679                 }
1680
1681                 // Avoid PHP 7.1 warning of passing $this by reference
1682                 $revision = $this;
1683                 Hooks::run( 'RevisionInsertComplete', [ &$revision, $data, $flags ] );
1684
1685                 return $this->mId;
1686         }
1687
1688         protected function checkContentModel() {
1689                 global $wgContentHandlerUseDB;
1690
1691                 // Note: may return null for revisions that have not yet been inserted
1692                 $title = $this->getTitle();
1693
1694                 $model = $this->getContentModel();
1695                 $format = $this->getContentFormat();
1696                 $handler = $this->getContentHandler();
1697
1698                 if ( !$handler->isSupportedFormat( $format ) ) {
1699                         $t = $title->getPrefixedDBkey();
1700
1701                         throw new MWException( "Can't use format $format with content model $model on $t" );
1702                 }
1703
1704                 if ( !$wgContentHandlerUseDB && $title ) {
1705                         // if $wgContentHandlerUseDB is not set,
1706                         // all revisions must use the default content model and format.
1707
1708                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1709                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1710                         $defaultFormat = $defaultHandler->getDefaultFormat();
1711
1712                         if ( $this->getContentModel() != $defaultModel ) {
1713                                 $t = $title->getPrefixedDBkey();
1714
1715                                 throw new MWException( "Can't save non-default content model with "
1716                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1717                                         . "default for $t is $defaultModel" );
1718                         }
1719
1720                         if ( $this->getContentFormat() != $defaultFormat ) {
1721                                 $t = $title->getPrefixedDBkey();
1722
1723                                 throw new MWException( "Can't use non-default content format with "
1724                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1725                                         . "default for $t is $defaultFormat" );
1726                         }
1727                 }
1728
1729                 $content = $this->getContent( self::RAW );
1730                 $prefixedDBkey = $title->getPrefixedDBkey();
1731                 $revId = $this->mId;
1732
1733                 if ( !$content ) {
1734                         throw new MWException(
1735                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1736                         );
1737                 }
1738                 if ( !$content->isValid() ) {
1739                         throw new MWException(
1740                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1741                         );
1742                 }
1743         }
1744
1745         /**
1746          * Get the base 36 SHA-1 value for a string of text
1747          * @param string $text
1748          * @return string
1749          */
1750         public static function base36Sha1( $text ) {
1751                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1752         }
1753
1754         /**
1755          * Get the text cache TTL
1756          *
1757          * @param WANObjectCache $cache
1758          * @return int
1759          */
1760         private static function getCacheTTL( WANObjectCache $cache ) {
1761                 global $wgRevisionCacheExpiry;
1762
1763                 if ( $cache->getQoS( $cache::ATTR_EMULATION ) <= $cache::QOS_EMULATION_SQL ) {
1764                         // Do not cache RDBMs blobs in...the RDBMs store
1765                         $ttl = $cache::TTL_UNCACHEABLE;
1766                 } else {
1767                         $ttl = $wgRevisionCacheExpiry ?: $cache::TTL_UNCACHEABLE;
1768                 }
1769
1770                 return $ttl;
1771         }
1772
1773         /**
1774          * Lazy-load the revision's text.
1775          * Currently hardcoded to the 'text' table storage engine.
1776          *
1777          * @return string|bool The revision's text, or false on failure
1778          */
1779         private function loadText() {
1780                 $cache = ObjectCache::getMainWANInstance();
1781
1782                 // No negative caching; negative hits on text rows may be due to corrupted replica DBs
1783                 return $cache->getWithSetCallback(
1784                         $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
1785                         self::getCacheTTL( $cache ),
1786                         function () {
1787                                 return $this->fetchText();
1788                         },
1789                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1790                 );
1791         }
1792
1793         private function fetchText() {
1794                 $textId = $this->getTextId();
1795
1796                 // If we kept data for lazy extraction, use it now...
1797                 if ( $this->mTextRow !== null ) {
1798                         $row = $this->mTextRow;
1799                         $this->mTextRow = null;
1800                 } else {
1801                         $row = null;
1802                 }
1803
1804                 // Callers doing updates will pass in READ_LATEST as usual. Since the text/blob tables
1805                 // do not normally get rows changed around, set READ_LATEST_IMMUTABLE in those cases.
1806                 $flags = $this->mQueryFlags;
1807                 $flags |= DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST )
1808                         ? self::READ_LATEST_IMMUTABLE
1809                         : 0;
1810
1811                 list( $index, $options, $fallbackIndex, $fallbackOptions ) =
1812                         DBAccessObjectUtils::getDBOptions( $flags );
1813
1814                 if ( !$row ) {
1815                         // Text data is immutable; check replica DBs first.
1816                         $row = wfGetDB( $index )->selectRow(
1817                                 'text',
1818                                 [ 'old_text', 'old_flags' ],
1819                                 [ 'old_id' => $textId ],
1820                                 __METHOD__,
1821                                 $options
1822                         );
1823                 }
1824
1825                 // Fallback to DB_MASTER in some cases if the row was not found
1826                 if ( !$row && $fallbackIndex !== null ) {
1827                         // Use FOR UPDATE if it was used to fetch this revision. This avoids missing the row
1828                         // due to REPEATABLE-READ. Also fallback to the master if READ_LATEST is provided.
1829                         $row = wfGetDB( $fallbackIndex )->selectRow(
1830                                 'text',
1831                                 [ 'old_text', 'old_flags' ],
1832                                 [ 'old_id' => $textId ],
1833                                 __METHOD__,
1834                                 $fallbackOptions
1835                         );
1836                 }
1837
1838                 if ( !$row ) {
1839                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1840                 }
1841
1842                 $text = self::getRevisionText( $row );
1843                 if ( $row && $text === false ) {
1844                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1845                 }
1846
1847                 return is_string( $text ) ? $text : false;
1848         }
1849
1850         /**
1851          * Create a new null-revision for insertion into a page's
1852          * history. This will not re-save the text, but simply refer
1853          * to the text from the previous version.
1854          *
1855          * Such revisions can for instance identify page rename
1856          * operations and other such meta-modifications.
1857          *
1858          * @param IDatabase $dbw
1859          * @param int $pageId ID number of the page to read from
1860          * @param string $summary Revision's summary
1861          * @param bool $minor Whether the revision should be considered as minor
1862          * @param User|null $user User object to use or null for $wgUser
1863          * @return Revision|null Revision or null on error
1864          */
1865         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1866                 global $wgContentHandlerUseDB;
1867
1868                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1869                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1870
1871                 if ( $wgContentHandlerUseDB ) {
1872                         $fields[] = 'rev_content_model';
1873                         $fields[] = 'rev_content_format';
1874                 }
1875
1876                 $current = $dbw->selectRow(
1877                         [ 'page', 'revision' ],
1878                         $fields,
1879                         [
1880                                 'page_id' => $pageId,
1881                                 'page_latest=rev_id',
1882                         ],
1883                         __METHOD__,
1884                         [ 'FOR UPDATE' ] // T51581
1885                 );
1886
1887                 if ( $current ) {
1888                         if ( !$user ) {
1889                                 global $wgUser;
1890                                 $user = $wgUser;
1891                         }
1892
1893                         $row = [
1894                                 'page'       => $pageId,
1895                                 'user_text'  => $user->getName(),
1896                                 'user'       => $user->getId(),
1897                                 'comment'    => $summary,
1898                                 'minor_edit' => $minor,
1899                                 'text_id'    => $current->rev_text_id,
1900                                 'parent_id'  => $current->page_latest,
1901                                 'len'        => $current->rev_len,
1902                                 'sha1'       => $current->rev_sha1
1903                         ];
1904
1905                         if ( $wgContentHandlerUseDB ) {
1906                                 $row['content_model'] = $current->rev_content_model;
1907                                 $row['content_format'] = $current->rev_content_format;
1908                         }
1909
1910                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1911
1912                         $revision = new Revision( $row );
1913                 } else {
1914                         $revision = null;
1915                 }
1916
1917                 return $revision;
1918         }
1919
1920         /**
1921          * Determine if the current user is allowed to view a particular
1922          * field of this revision, if it's marked as deleted.
1923          *
1924          * @param int $field One of self::DELETED_TEXT,
1925          *                              self::DELETED_COMMENT,
1926          *                              self::DELETED_USER
1927          * @param User|null $user User object to check, or null to use $wgUser
1928          * @return bool
1929          */
1930         public function userCan( $field, User $user = null ) {
1931                 return self::userCanBitfield( $this->getVisibility(), $field, $user );
1932         }
1933
1934         /**
1935          * Determine if the current user is allowed to view a particular
1936          * field of this revision, if it's marked as deleted. This is used
1937          * by various classes to avoid duplication.
1938          *
1939          * @param int $bitfield Current field
1940          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1941          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1942          *                               self::DELETED_USER = File::DELETED_USER
1943          * @param User|null $user User object to check, or null to use $wgUser
1944          * @param Title|null $title A Title object to check for per-page restrictions on,
1945          *                          instead of just plain userrights
1946          * @return bool
1947          */
1948         public static function userCanBitfield( $bitfield, $field, User $user = null,
1949                 Title $title = null
1950         ) {
1951                 if ( $bitfield & $field ) { // aspect is deleted
1952                         if ( $user === null ) {
1953                                 global $wgUser;
1954                                 $user = $wgUser;
1955                         }
1956                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1957                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1958                         } elseif ( $field & self::DELETED_TEXT ) {
1959                                 $permissions = [ 'deletedtext' ];
1960                         } else {
1961                                 $permissions = [ 'deletedhistory' ];
1962                         }
1963                         $permissionlist = implode( ', ', $permissions );
1964                         if ( $title === null ) {
1965                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1966                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1967                         } else {
1968                                 $text = $title->getPrefixedText();
1969                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1970                                 foreach ( $permissions as $perm ) {
1971                                         if ( $title->userCan( $perm, $user ) ) {
1972                                                 return true;
1973                                         }
1974                                 }
1975                                 return false;
1976                         }
1977                 } else {
1978                         return true;
1979                 }
1980         }
1981
1982         /**
1983          * Get rev_timestamp from rev_id, without loading the rest of the row
1984          *
1985          * @param Title $title
1986          * @param int $id
1987          * @param int $flags
1988          * @return string|bool False if not found
1989          */
1990         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1991                 $db = ( $flags & self::READ_LATEST )
1992                         ? wfGetDB( DB_MASTER )
1993                         : wfGetDB( DB_REPLICA );
1994                 // Casting fix for databases that can't take '' for rev_id
1995                 if ( $id == '' ) {
1996                         $id = 0;
1997                 }
1998                 $conds = [ 'rev_id' => $id ];
1999                 $conds['rev_page'] = $title->getArticleID();
2000                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
2001
2002                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
2003         }
2004
2005         /**
2006          * Get count of revisions per page...not very efficient
2007          *
2008          * @param IDatabase $db
2009          * @param int $id Page id
2010          * @return int
2011          */
2012         static function countByPageId( $db, $id ) {
2013                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
2014                         [ 'rev_page' => $id ], __METHOD__ );
2015                 if ( $row ) {
2016                         return $row->revCount;
2017                 }
2018                 return 0;
2019         }
2020
2021         /**
2022          * Get count of revisions per page...not very efficient
2023          *
2024          * @param IDatabase $db
2025          * @param Title $title
2026          * @return int
2027          */
2028         static function countByTitle( $db, $title ) {
2029                 $id = $title->getArticleID();
2030                 if ( $id ) {
2031                         return self::countByPageId( $db, $id );
2032                 }
2033                 return 0;
2034         }
2035
2036         /**
2037          * Check if no edits were made by other users since
2038          * the time a user started editing the page. Limit to
2039          * 50 revisions for the sake of performance.
2040          *
2041          * @since 1.20
2042          * @deprecated since 1.24
2043          *
2044          * @param IDatabase|int $db The Database to perform the check on. May be given as a
2045          *        Database object or a database identifier usable with wfGetDB.
2046          * @param int $pageId The ID of the page in question
2047          * @param int $userId The ID of the user in question
2048          * @param string $since Look at edits since this time
2049          *
2050          * @return bool True if the given user was the only one to edit since the given timestamp
2051          */
2052         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
2053                 if ( !$userId ) {
2054                         return false;
2055                 }
2056
2057                 if ( is_int( $db ) ) {
2058                         $db = wfGetDB( $db );
2059                 }
2060
2061                 $res = $db->select( 'revision',
2062                         'rev_user',
2063                         [
2064                                 'rev_page' => $pageId,
2065                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
2066                         ],
2067                         __METHOD__,
2068                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
2069                 foreach ( $res as $row ) {
2070                         if ( $row->rev_user != $userId ) {
2071                                 return false;
2072                         }
2073                 }
2074                 return true;
2075         }
2076
2077         /**
2078          * Load a revision based on a known page ID and current revision ID from the DB
2079          *
2080          * This method allows for the use of caching, though accessing anything that normally
2081          * requires permission checks (aside from the text) will trigger a small DB lookup.
2082          * The title will also be lazy loaded, though setTitle() can be used to preload it.
2083          *
2084          * @param IDatabase $db
2085          * @param int $pageId Page ID
2086          * @param int $revId Known current revision of this page
2087          * @return Revision|bool Returns false if missing
2088          * @since 1.28
2089          */
2090         public static function newKnownCurrent( IDatabase $db, $pageId, $revId ) {
2091                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
2092                 return $cache->getWithSetCallback(
2093                         // Page/rev IDs passed in from DB to reflect history merges
2094                         $cache->makeGlobalKey( 'revision', $db->getDomainID(), $pageId, $revId ),
2095                         $cache::TTL_WEEK,
2096                         function ( $curValue, &$ttl, array &$setOpts ) use ( $db, $pageId, $revId ) {
2097                                 $setOpts += Database::getCacheSetOptions( $db );
2098
2099                                 $rev = Revision::loadFromPageId( $db, $pageId, $revId );
2100                                 // Reflect revision deletion and user renames
2101                                 if ( $rev ) {
2102                                         $rev->mTitle = null; // mutable; lazy-load
2103                                         $rev->mRefreshMutableFields = true;
2104                                 }
2105
2106                                 return $rev ?: false; // don't cache negatives
2107                         }
2108                 );
2109         }
2110
2111         /**
2112          * For cached revisions, make sure the user name and rev_deleted is up-to-date
2113          */
2114         private function loadMutableFields() {
2115                 if ( !$this->mRefreshMutableFields ) {
2116                         return; // not needed
2117                 }
2118
2119                 $this->mRefreshMutableFields = false;
2120                 $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
2121                 $row = $dbr->selectRow(
2122                         [ 'revision', 'user' ],
2123                         [ 'rev_deleted', 'user_name' ],
2124                         [ 'rev_id' => $this->mId, 'user_id = rev_user' ],
2125                         __METHOD__
2126                 );
2127                 if ( $row ) { // update values
2128                         $this->mDeleted = (int)$row->rev_deleted;
2129                         $this->mUserText = $row->user_name;
2130                 }
2131         }
2132 }