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          * @param int $id User ID
 905          * @param string $name User name
 906          */
 907         public function setUserIdAndName( $id, $name ) {
 908                 $this->mUser = (int)$id;
 909                 $this->mUserText = $name;
 910                 $this->mOrigUserText = $name;
 911         }
 912
 913         /**
 914          * Get text row ID
 915          *
 916          * @return int|null
 917          */
 918         public function getTextId() {
 919                 return $this->mTextId;
 920         }
 921
 922         /**
 923          * Get parent revision ID (the original previous page revision)
 924          *
 925          * @return int|null
 926          */
 927         public function getParentId() {
 928                 return $this->mParentId;
 929         }
 930
 931         /**
 932          * Returns the length of the text in this revision, or null if unknown.
 933          *
 934          * @return int|null
 935          */
 936         public function getSize() {
 937                 return $this->mSize;
 938         }
 939
 940         /**
 941          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 942          *
 943          * @return string|null
 944          */
 945         public function getSha1() {
 946                 return $this->mSha1;
 947         }
 948
 949         /**
 950          * Returns the title of the page associated with this entry or null.
 951          *
 952          * Will do a query, when title is not set and id is given.
 953          *
 954          * @return Title|null
 955          */
 956         public function getTitle() {
 957                 if ( $this->mTitle !== null ) {
 958                         return $this->mTitle;
 959                 }
 960                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 961                 if ( $this->mId !== null ) {
 962                         $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
 963                         // @todo: Title::getSelectFields(), or Title::getQueryInfo(), or something like that
 964                         $row = $dbr->selectRow(
 965                                 [ 'revision', 'page' ],
 966                                 [
 967                                         'page_namespace',
 968                                         'page_title',
 969                                         'page_id',
 970                                         'page_latest',
 971                                         'page_is_redirect',
 972                                         'page_len',
 973                                 ],
 974                                 [ 'rev_id' => $this->mId ],
 975                                 __METHOD__,
 976                                 [],
 977                                 [ 'page' => [ 'JOIN', 'page_id=rev_page' ] ]
 978                         );
 979                         if ( $row ) {
 980                                 // @TODO: better foreign title handling
 981                                 $this->mTitle = Title::newFromRow( $row );
 982                         }
 983                 }
 984
 985                 if ( $this->mWiki === false || $this->mWiki === wfWikiID() ) {
 986                         // Loading by ID is best, though not possible for foreign titles
 987                         if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 988                                 $this->mTitle = Title::newFromID( $this->mPage );
 989                         }
 990                 }
 991
 992                 return $this->mTitle;
 993         }
 994
 995         /**
 996          * Set the title of the revision
 997          *
 998          * @param Title $title
 999          */
1000         public function setTitle( $title ) {
1001                 $this->mTitle = $title;
1002         }
1003
1004         /**
1005          * Get the page ID
1006          *
1007          * @return int|null
1008          */
1009         public function getPage() {
1010                 return $this->mPage;
1011         }
1012
1013         /**
1014          * Fetch revision's user id if it's available to the specified audience.
1015          * If the specified audience does not have access to it, zero will be
1016          * returned.
1017          *
1018          * @param int $audience One of:
1019          *   Revision::FOR_PUBLIC       to be displayed to all users
1020          *   Revision::FOR_THIS_USER    to be displayed to the given user
1021          *   Revision::RAW              get the ID regardless of permissions
1022          * @param User|null $user User object to check for, only if FOR_THIS_USER is passed
1023          *   to the $audience parameter
1024          * @return int
1025          */
1026         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
1027                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
1028                         return 0;
1029                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
1030                         return 0;
1031                 } else {
1032                         return $this->mUser;
1033                 }
1034         }
1035
1036         /**
1037          * Fetch revision's user id without regard for the current user's permissions
1038          *
1039          * @return int
1040          * @deprecated since 1.25, use getUser( Revision::RAW )
1041          */
1042         public function getRawUser() {
1043                 wfDeprecated( __METHOD__, '1.25' );
1044                 return $this->getUser( self::RAW );
1045         }
1046
1047         /**
1048          * Fetch revision's username if it's available to the specified audience.
1049          * If the specified audience does not have access to the username, an
1050          * empty string will be returned.
1051          *
1052          * @param int $audience One of:
1053          *   Revision::FOR_PUBLIC       to be displayed to all users
1054          *   Revision::FOR_THIS_USER    to be displayed to the given user
1055          *   Revision::RAW              get the text regardless of permissions
1056          * @param User|null $user User object to check for, only if FOR_THIS_USER is passed
1057          *   to the $audience parameter
1058          * @return string
1059          */
1060         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
1061                 $this->loadMutableFields();
1062
1063                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
1064                         return '';
1065                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
1066                         return '';
1067                 } else {
1068                         if ( $this->mUserText === null ) {
1069                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
1070                                 if ( $this->mUserText === false ) {
1071                                         # This shouldn't happen, but it can if the wiki was recovered
1072                                         # via importing revs and there is no user table entry yet.
1073                                         $this->mUserText = $this->mOrigUserText;
1074                                 }
1075                         }
1076                         return $this->mUserText;
1077                 }
1078         }
1079
1080         /**
1081          * Fetch revision's username without regard for view restrictions
1082          *
1083          * @return string
1084          * @deprecated since 1.25, use getUserText( Revision::RAW )
1085          */
1086         public function getRawUserText() {
1087                 wfDeprecated( __METHOD__, '1.25' );
1088                 return $this->getUserText( self::RAW );
1089         }
1090
1091         /**
1092          * Fetch revision comment if it's available to the specified audience.
1093          * If the specified audience does not have access to the comment, an
1094          * empty string will be returned.
1095          *
1096          * @param int $audience One of:
1097          *   Revision::FOR_PUBLIC       to be displayed to all users
1098          *   Revision::FOR_THIS_USER    to be displayed to the given user
1099          *   Revision::RAW              get the text regardless of permissions
1100          * @param User|null $user User object to check for, only if FOR_THIS_USER is passed
1101          *   to the $audience parameter
1102          * @return string
1103          */
1104         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
1105                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
1106                         return '';
1107                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
1108                         return '';
1109                 } else {
1110                         return $this->mComment;
1111                 }
1112         }
1113
1114         /**
1115          * Fetch revision comment without regard for the current user's permissions
1116          *
1117          * @return string
1118          * @deprecated since 1.25, use getComment( Revision::RAW )
1119          */
1120         public function getRawComment() {
1121                 wfDeprecated( __METHOD__, '1.25' );
1122                 return $this->getComment( self::RAW );
1123         }
1124
1125         /**
1126          * @return bool
1127          */
1128         public function isMinor() {
1129                 return (bool)$this->mMinorEdit;
1130         }
1131
1132         /**
1133          * @return int Rcid of the unpatrolled row, zero if there isn't one
1134          */
1135         public function isUnpatrolled() {
1136                 if ( $this->mUnpatrolled !== null ) {
1137                         return $this->mUnpatrolled;
1138                 }
1139                 $rc = $this->getRecentChange();
1140                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
1141                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
1142                 } else {
1143                         $this->mUnpatrolled = 0;
1144                 }
1145                 return $this->mUnpatrolled;
1146         }
1147
1148         /**
1149          * Get the RC object belonging to the current revision, if there's one
1150          *
1151          * @param int $flags (optional) $flags include:
1152          *      Revision::READ_LATEST  : Select the data from the master
1153          *
1154          * @since 1.22
1155          * @return RecentChange|null
1156          */
1157         public function getRecentChange( $flags = 0 ) {
1158                 $dbr = wfGetDB( DB_REPLICA );
1159
1160                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
1161
1162                 return RecentChange::newFromConds(
1163                         [
1164                                 'rc_user_text' => $this->getUserText( self::RAW ),
1165                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
1166                                 'rc_this_oldid' => $this->getId()
1167                         ],
1168                         __METHOD__,
1169                         $dbType
1170                 );
1171         }
1172
1173         /**
1174          * @param int $field One of DELETED_* bitfield constants
1175          *
1176          * @return bool
1177          */
1178         public function isDeleted( $field ) {
1179                 if ( $this->isCurrent() && $field === self::DELETED_TEXT ) {
1180                         // Current revisions of pages cannot have the content hidden. Skipping this
1181                         // check is very useful for Parser as it fetches templates using newKnownCurrent().
1182                         // Calling getVisibility() in that case triggers a verification database query.
1183                         return false; // no need to check
1184                 }
1185
1186                 return ( $this->getVisibility() & $field ) == $field;
1187         }
1188
1189         /**
1190          * Get the deletion bitfield of the revision
1191          *
1192          * @return int
1193          */
1194         public function getVisibility() {
1195                 $this->loadMutableFields();
1196
1197                 return (int)$this->mDeleted;
1198         }
1199
1200         /**
1201          * Fetch revision content if it's available to the specified audience.
1202          * If the specified audience does not have the ability to view this
1203          * revision, null will be returned.
1204          *
1205          * @param int $audience One of:
1206          *   Revision::FOR_PUBLIC       to be displayed to all users
1207          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1208          *   Revision::RAW              get the text regardless of permissions
1209          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1210          *   to the $audience parameter
1211          * @since 1.21
1212          * @return Content|null
1213          */
1214         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1215                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1216                         return null;
1217                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1218                         return null;
1219                 } else {
1220                         return $this->getContentInternal();
1221                 }
1222         }
1223
1224         /**
1225          * Get original serialized data (without checking view restrictions)
1226          *
1227          * @since 1.21
1228          * @return string
1229          */
1230         public function getSerializedData() {
1231                 if ( $this->mText === null ) {
1232                         // Revision is immutable. Load on demand.
1233                         $this->mText = $this->loadText();
1234                 }
1235
1236                 return $this->mText;
1237         }
1238
1239         /**
1240          * Gets the content object for the revision (or null on failure).
1241          *
1242          * Note that for mutable Content objects, each call to this method will return a
1243          * fresh clone.
1244          *
1245          * @since 1.21
1246          * @return Content|null The Revision's content, or null on failure.
1247          */
1248         protected function getContentInternal() {
1249                 if ( $this->mContent === null ) {
1250                         $text = $this->getSerializedData();
1251
1252                         if ( $text !== null && $text !== false ) {
1253                                 // Unserialize content
1254                                 $handler = $this->getContentHandler();
1255                                 $format = $this->getContentFormat();
1256
1257                                 $this->mContent = $handler->unserializeContent( $text, $format );
1258                         }
1259                 }
1260
1261                 // NOTE: copy() will return $this for immutable content objects
1262                 return $this->mContent ? $this->mContent->copy() : null;
1263         }
1264
1265         /**
1266          * Returns the content model for this revision.
1267          *
1268          * If no content model was stored in the database, the default content model for the title is
1269          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1270          * is used as a last resort.
1271          *
1272          * @return string The content model id associated with this revision,
1273          *     see the CONTENT_MODEL_XXX constants.
1274          */
1275         public function getContentModel() {
1276                 if ( !$this->mContentModel ) {
1277                         $title = $this->getTitle();
1278                         if ( $title ) {
1279                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1280                         } else {
1281                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1282                         }
1283
1284                         assert( !empty( $this->mContentModel ) );
1285                 }
1286
1287                 return $this->mContentModel;
1288         }
1289
1290         /**
1291          * Returns the content format for this revision.
1292          *
1293          * If no content format was stored in the database, the default format for this
1294          * revision's content model is returned.
1295          *
1296          * @return string The content format id associated with this revision,
1297          *     see the CONTENT_FORMAT_XXX constants.
1298          */
1299         public function getContentFormat() {
1300                 if ( !$this->mContentFormat ) {
1301                         $handler = $this->getContentHandler();
1302                         $this->mContentFormat = $handler->getDefaultFormat();
1303
1304                         assert( !empty( $this->mContentFormat ) );
1305                 }
1306
1307                 return $this->mContentFormat;
1308         }
1309
1310         /**
1311          * Returns the content handler appropriate for this revision's content model.
1312          *
1313          * @throws MWException
1314          * @return ContentHandler
1315          */
1316         public function getContentHandler() {
1317                 if ( !$this->mContentHandler ) {
1318                         $model = $this->getContentModel();
1319                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1320
1321                         $format = $this->getContentFormat();
1322
1323                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1324                                 throw new MWException( "Oops, the content format $format is not supported for "
1325                                         . "this content model, $model" );
1326                         }
1327                 }
1328
1329                 return $this->mContentHandler;
1330         }
1331
1332         /**
1333          * @return string
1334          */
1335         public function getTimestamp() {
1336                 return wfTimestamp( TS_MW, $this->mTimestamp );
1337         }
1338
1339         /**
1340          * @return bool
1341          */
1342         public function isCurrent() {
1343                 return $this->mCurrent;
1344         }
1345
1346         /**
1347          * Get previous revision for this title
1348          *
1349          * @return Revision|null
1350          */
1351         public function getPrevious() {
1352                 if ( $this->getTitle() ) {
1353                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1354                         if ( $prev ) {
1355                                 return self::newFromTitle( $this->getTitle(), $prev );
1356                         }
1357                 }
1358                 return null;
1359         }
1360
1361         /**
1362          * Get next revision for this title
1363          *
1364          * @return Revision|null
1365          */
1366         public function getNext() {
1367                 if ( $this->getTitle() ) {
1368                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1369                         if ( $next ) {
1370                                 return self::newFromTitle( $this->getTitle(), $next );
1371                         }
1372                 }
1373                 return null;
1374         }
1375
1376         /**
1377          * Get previous revision Id for this page_id
1378          * This is used to populate rev_parent_id on save
1379          *
1380          * @param IDatabase $db
1381          * @return int
1382          */
1383         private function getPreviousRevisionId( $db ) {
1384                 if ( $this->mPage === null ) {
1385                         return 0;
1386                 }
1387                 # Use page_latest if ID is not given
1388                 if ( !$this->mId ) {
1389                         $prevId = $db->selectField( 'page', 'page_latest',
1390                                 [ 'page_id' => $this->mPage ],
1391                                 __METHOD__ );
1392                 } else {
1393                         $prevId = $db->selectField( 'revision', 'rev_id',
1394                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1395                                 __METHOD__,
1396                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1397                 }
1398                 return intval( $prevId );
1399         }
1400
1401         /**
1402          * Get revision text associated with an old or archive row
1403          *
1404          * Both the flags and the text field must be included. Including the old_id
1405          * field will activate cache usage as long as the $wiki parameter is not set.
1406          *
1407          * @param stdClass $row The text data
1408          * @param string $prefix Table prefix (default 'old_')
1409          * @param string|bool $wiki The name of the wiki to load the revision text from
1410          *   (same as the the wiki $row was loaded from) or false to indicate the local
1411          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1412          *   identifier as understood by the LoadBalancer class.
1413          * @return string|false Text the text requested or false on failure
1414          */
1415         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1416                 $textField = $prefix . 'text';
1417                 $flagsField = $prefix . 'flags';
1418
1419                 if ( isset( $row->$flagsField ) ) {
1420                         $flags = explode( ',', $row->$flagsField );
1421                 } else {
1422                         $flags = [];
1423                 }
1424
1425                 if ( isset( $row->$textField ) ) {
1426                         $text = $row->$textField;
1427                 } else {
1428                         return false;
1429                 }
1430
1431                 // Use external methods for external objects, text in table is URL-only then
1432                 if ( in_array( 'external', $flags ) ) {
1433                         $url = $text;
1434                         $parts = explode( '://', $url, 2 );
1435                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1436                                 return false;
1437                         }
1438
1439                         if ( isset( $row->old_id ) && $wiki === false ) {
1440                                 // Make use of the wiki-local revision text cache
1441                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1442                                 // The cached value should be decompressed, so handle that and return here
1443                                 return $cache->getWithSetCallback(
1444                                         $cache->makeKey( 'revisiontext', 'textid', $row->old_id ),
1445                                         self::getCacheTTL( $cache ),
1446                                         function () use ( $url, $wiki, $flags ) {
1447                                                 // No negative caching per Revision::loadText()
1448                                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1449
1450                                                 return self::decompressRevisionText( $text, $flags );
1451                                         },
1452                                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1453                                 );
1454                         } else {
1455                                 $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1456                         }
1457                 }
1458
1459                 return self::decompressRevisionText( $text, $flags );
1460         }
1461
1462         /**
1463          * If $wgCompressRevisions is enabled, we will compress data.
1464          * The input string is modified in place.
1465          * Return value is the flags field: contains 'gzip' if the
1466          * data is compressed, and 'utf-8' if we're saving in UTF-8
1467          * mode.
1468          *
1469          * @param mixed &$text Reference to a text
1470          * @return string
1471          */
1472         public static function compressRevisionText( &$text ) {
1473                 global $wgCompressRevisions;
1474                 $flags = [];
1475
1476                 # Revisions not marked this way will be converted
1477                 # on load if $wgLegacyCharset is set in the future.
1478                 $flags[] = 'utf-8';
1479
1480                 if ( $wgCompressRevisions ) {
1481                         if ( function_exists( 'gzdeflate' ) ) {
1482                                 $deflated = gzdeflate( $text );
1483
1484                                 if ( $deflated === false ) {
1485                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1486                                 } else {
1487                                         $text = $deflated;
1488                                         $flags[] = 'gzip';
1489                                 }
1490                         } else {
1491                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1492                         }
1493                 }
1494                 return implode( ',', $flags );
1495         }
1496
1497         /**
1498          * Re-converts revision text according to it's flags.
1499          *
1500          * @param mixed $text Reference to a text
1501          * @param array $flags Compression flags
1502          * @return string|bool Decompressed text, or false on failure
1503          */
1504         public static function decompressRevisionText( $text, $flags ) {
1505                 global $wgLegacyEncoding, $wgContLang;
1506
1507                 if ( $text === false ) {
1508                         // Text failed to be fetched; nothing to do
1509                         return false;
1510                 }
1511
1512                 if ( in_array( 'gzip', $flags ) ) {
1513                         # Deal with optional compression of archived pages.
1514                         # This can be done periodically via maintenance/compressOld.php, and
1515                         # as pages are saved if $wgCompressRevisions is set.
1516                         $text = gzinflate( $text );
1517
1518                         if ( $text === false ) {
1519                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1520                                 return false;
1521                         }
1522                 }
1523
1524                 if ( in_array( 'object', $flags ) ) {
1525                         # Generic compressed storage
1526                         $obj = unserialize( $text );
1527                         if ( !is_object( $obj ) ) {
1528                                 // Invalid object
1529                                 return false;
1530                         }
1531                         $text = $obj->getText();
1532                 }
1533
1534                 if ( $text !== false && $wgLegacyEncoding
1535                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1536                 ) {
1537                         # Old revisions kept around in a legacy encoding?
1538                         # Upconvert on demand.
1539                         # ("utf8" checked for compatibility with some broken
1540                         #  conversion scripts 2008-12-30)
1541                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1542                 }
1543
1544                 return $text;
1545         }
1546
1547         /**
1548          * Insert a new revision into the database, returning the new revision ID
1549          * number on success and dies horribly on failure.
1550          *
1551          * @param IDatabase $dbw (master connection)
1552          * @throws MWException
1553          * @return int The revision ID
1554          */
1555         public function insertOn( $dbw ) {
1556                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1557
1558                 // We're inserting a new revision, so we have to use master anyway.
1559                 // If it's a null revision, it may have references to rows that
1560                 // are not in the replica yet (the text row).
1561                 $this->mQueryFlags |= self::READ_LATEST;
1562
1563                 // Not allowed to have rev_page equal to 0, false, etc.
1564                 if ( !$this->mPage ) {
1565                         $title = $this->getTitle();
1566                         if ( $title instanceof Title ) {
1567                                 $titleText = ' for page ' . $title->getPrefixedText();
1568                         } else {
1569                                 $titleText = '';
1570                         }
1571                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1572                 }
1573
1574                 $this->checkContentModel();
1575
1576                 $data = $this->mText;
1577                 $flags = self::compressRevisionText( $data );
1578
1579                 # Write to external storage if required
1580                 if ( $wgDefaultExternalStore ) {
1581                         // Store and get the URL
1582                         $data = ExternalStore::insertToDefault( $data );
1583                         if ( !$data ) {
1584                                 throw new MWException( "Unable to store text to external storage" );
1585                         }
1586                         if ( $flags ) {
1587                                 $flags .= ',';
1588                         }
1589                         $flags .= 'external';
1590                 }
1591
1592                 # Record the text (or external storage URL) to the text table
1593                 if ( $this->mTextId === null ) {
1594                         $dbw->insert( 'text',
1595                                 [
1596                                         'old_text' => $data,
1597                                         'old_flags' => $flags,
1598                                 ], __METHOD__
1599                         );
1600                         $this->mTextId = $dbw->insertId();
1601                 }
1602
1603                 if ( $this->mComment === null ) {
1604                         $this->mComment = "";
1605                 }
1606
1607                 # Record the edit in revisions
1608                 $row = [
1609                         'rev_page'       => $this->mPage,
1610                         'rev_text_id'    => $this->mTextId,
1611                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1612                         'rev_user'       => $this->mUser,
1613                         'rev_user_text'  => $this->mUserText,
1614                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1615                         'rev_deleted'    => $this->mDeleted,
1616                         'rev_len'        => $this->mSize,
1617                         'rev_parent_id'  => $this->mParentId === null
1618                                 ? $this->getPreviousRevisionId( $dbw )
1619                                 : $this->mParentId,
1620                         'rev_sha1'       => $this->mSha1 === null
1621                                 ? self::base36Sha1( $this->mText )
1622                                 : $this->mSha1,
1623                 ];
1624                 if ( $this->mId !== null ) {
1625                         $row['rev_id'] = $this->mId;
1626                 }
1627
1628                 list( $commentFields, $commentCallback ) =
1629                         CommentStore::newKey( 'rev_comment' )->insertWithTempTable( $dbw, $this->mComment );
1630                 $row += $commentFields;
1631
1632                 if ( $wgContentHandlerUseDB ) {
1633                         // NOTE: Store null for the default model and format, to save space.
1634                         // XXX: Makes the DB sensitive to changed defaults.
1635                         // Make this behavior optional? Only in miser mode?
1636
1637                         $model = $this->getContentModel();
1638                         $format = $this->getContentFormat();
1639
1640                         $title = $this->getTitle();
1641
1642                         if ( $title === null ) {
1643                                 throw new MWException( "Insufficient information to determine the title of the "
1644                                         . "revision's page!" );
1645                         }
1646
1647                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1648                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1649
1650                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1651                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1652                 }
1653
1654                 $dbw->insert( 'revision', $row, __METHOD__ );
1655
1656                 if ( $this->mId === null ) {
1657                         // Only if auto-increment was used
1658                         $this->mId = $dbw->insertId();
1659                 }
1660                 $commentCallback( $this->mId );
1661
1662                 // Assertion to try to catch T92046
1663                 if ( (int)$this->mId === 0 ) {
1664                         throw new UnexpectedValueException(
1665                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1666                                         var_export( $row, 1 )
1667                         );
1668                 }
1669
1670                 // Insert IP revision into ip_changes for use when querying for a range.
1671                 if ( $this->mUser === 0 && IP::isValid( $this->mUserText ) ) {
1672                         $ipcRow = [
1673                                 'ipc_rev_id'        => $this->mId,
1674                                 'ipc_rev_timestamp' => $row['rev_timestamp'],
1675                                 'ipc_hex'           => IP::toHex( $row['rev_user_text'] ),
1676                         ];
1677                         $dbw->insert( 'ip_changes', $ipcRow, __METHOD__ );
1678                 }
1679
1680                 // Avoid PHP 7.1 warning of passing $this by reference
1681                 $revision = $this;
1682                 Hooks::run( 'RevisionInsertComplete', [ &$revision, $data, $flags ] );
1683
1684                 return $this->mId;
1685         }
1686
1687         protected function checkContentModel() {
1688                 global $wgContentHandlerUseDB;
1689
1690                 // Note: may return null for revisions that have not yet been inserted
1691                 $title = $this->getTitle();
1692
1693                 $model = $this->getContentModel();
1694                 $format = $this->getContentFormat();
1695                 $handler = $this->getContentHandler();
1696
1697                 if ( !$handler->isSupportedFormat( $format ) ) {
1698                         $t = $title->getPrefixedDBkey();
1699
1700                         throw new MWException( "Can't use format $format with content model $model on $t" );
1701                 }
1702
1703                 if ( !$wgContentHandlerUseDB && $title ) {
1704                         // if $wgContentHandlerUseDB is not set,
1705                         // all revisions must use the default content model and format.
1706
1707                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1708                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1709                         $defaultFormat = $defaultHandler->getDefaultFormat();
1710
1711                         if ( $this->getContentModel() != $defaultModel ) {
1712                                 $t = $title->getPrefixedDBkey();
1713
1714                                 throw new MWException( "Can't save non-default content model with "
1715                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1716                                         . "default for $t is $defaultModel" );
1717                         }
1718
1719                         if ( $this->getContentFormat() != $defaultFormat ) {
1720                                 $t = $title->getPrefixedDBkey();
1721
1722                                 throw new MWException( "Can't use non-default content format with "
1723                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1724                                         . "default for $t is $defaultFormat" );
1725                         }
1726                 }
1727
1728                 $content = $this->getContent( self::RAW );
1729                 $prefixedDBkey = $title->getPrefixedDBkey();
1730                 $revId = $this->mId;
1731
1732                 if ( !$content ) {
1733                         throw new MWException(
1734                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1735                         );
1736                 }
1737                 if ( !$content->isValid() ) {
1738                         throw new MWException(
1739                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1740                         );
1741                 }
1742         }
1743
1744         /**
1745          * Get the base 36 SHA-1 value for a string of text
1746          * @param string $text
1747          * @return string
1748          */
1749         public static function base36Sha1( $text ) {
1750                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1751         }
1752
1753         /**
1754          * Get the text cache TTL
1755          *
1756          * @param WANObjectCache $cache
1757          * @return int
1758          */
1759         private static function getCacheTTL( WANObjectCache $cache ) {
1760                 global $wgRevisionCacheExpiry;
1761
1762                 if ( $cache->getQoS( $cache::ATTR_EMULATION ) <= $cache::QOS_EMULATION_SQL ) {
1763                         // Do not cache RDBMs blobs in...the RDBMs store
1764                         $ttl = $cache::TTL_UNCACHEABLE;
1765                 } else {
1766                         $ttl = $wgRevisionCacheExpiry ?: $cache::TTL_UNCACHEABLE;
1767                 }
1768
1769                 return $ttl;
1770         }
1771
1772         /**
1773          * Lazy-load the revision's text.
1774          * Currently hardcoded to the 'text' table storage engine.
1775          *
1776          * @return string|bool The revision's text, or false on failure
1777          */
1778         private function loadText() {
1779                 $cache = ObjectCache::getMainWANInstance();
1780
1781                 // No negative caching; negative hits on text rows may be due to corrupted replica DBs
1782                 return $cache->getWithSetCallback(
1783                         $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
1784                         self::getCacheTTL( $cache ),
1785                         function () {
1786                                 return $this->fetchText();
1787                         },
1788                         [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
1789                 );
1790         }
1791
1792         private function fetchText() {
1793                 $textId = $this->getTextId();
1794
1795                 // If we kept data for lazy extraction, use it now...
1796                 if ( $this->mTextRow !== null ) {
1797                         $row = $this->mTextRow;
1798                         $this->mTextRow = null;
1799                 } else {
1800                         $row = null;
1801                 }
1802
1803                 // Callers doing updates will pass in READ_LATEST as usual. Since the text/blob tables
1804                 // do not normally get rows changed around, set READ_LATEST_IMMUTABLE in those cases.
1805                 $flags = $this->mQueryFlags;
1806                 $flags |= DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST )
1807                         ? self::READ_LATEST_IMMUTABLE
1808                         : 0;
1809
1810                 list( $index, $options, $fallbackIndex, $fallbackOptions ) =
1811                         DBAccessObjectUtils::getDBOptions( $flags );
1812
1813                 if ( !$row ) {
1814                         // Text data is immutable; check replica DBs first.
1815                         $row = wfGetDB( $index )->selectRow(
1816                                 'text',
1817                                 [ 'old_text', 'old_flags' ],
1818                                 [ 'old_id' => $textId ],
1819                                 __METHOD__,
1820                                 $options
1821                         );
1822                 }
1823
1824                 // Fallback to DB_MASTER in some cases if the row was not found
1825                 if ( !$row && $fallbackIndex !== null ) {
1826                         // Use FOR UPDATE if it was used to fetch this revision. This avoids missing the row
1827                         // due to REPEATABLE-READ. Also fallback to the master if READ_LATEST is provided.
1828                         $row = wfGetDB( $fallbackIndex )->selectRow(
1829                                 'text',
1830                                 [ 'old_text', 'old_flags' ],
1831                                 [ 'old_id' => $textId ],
1832                                 __METHOD__,
1833                                 $fallbackOptions
1834                         );
1835                 }
1836
1837                 if ( !$row ) {
1838                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1839                 }
1840
1841                 $text = self::getRevisionText( $row );
1842                 if ( $row && $text === false ) {
1843                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1844                 }
1845
1846                 return is_string( $text ) ? $text : false;
1847         }
1848
1849         /**
1850          * Create a new null-revision for insertion into a page's
1851          * history. This will not re-save the text, but simply refer
1852          * to the text from the previous version.
1853          *
1854          * Such revisions can for instance identify page rename
1855          * operations and other such meta-modifications.
1856          *
1857          * @param IDatabase $dbw
1858          * @param int $pageId ID number of the page to read from
1859          * @param string $summary Revision's summary
1860          * @param bool $minor Whether the revision should be considered as minor
1861          * @param User|null $user User object to use or null for $wgUser
1862          * @return Revision|null Revision or null on error
1863          */
1864         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1865                 global $wgContentHandlerUseDB;
1866
1867                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1868                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1869
1870                 if ( $wgContentHandlerUseDB ) {
1871                         $fields[] = 'rev_content_model';
1872                         $fields[] = 'rev_content_format';
1873                 }
1874
1875                 $current = $dbw->selectRow(
1876                         [ 'page', 'revision' ],
1877                         $fields,
1878                         [
1879                                 'page_id' => $pageId,
1880                                 'page_latest=rev_id',
1881                         ],
1882                         __METHOD__,
1883                         [ 'FOR UPDATE' ] // T51581
1884                 );
1885
1886                 if ( $current ) {
1887                         if ( !$user ) {
1888                                 global $wgUser;
1889                                 $user = $wgUser;
1890                         }
1891
1892                         $row = [
1893                                 'page'       => $pageId,
1894                                 'user_text'  => $user->getName(),
1895                                 'user'       => $user->getId(),
1896                                 'comment'    => $summary,
1897                                 'minor_edit' => $minor,
1898                                 'text_id'    => $current->rev_text_id,
1899                                 'parent_id'  => $current->page_latest,
1900                                 'len'        => $current->rev_len,
1901                                 'sha1'       => $current->rev_sha1
1902                         ];
1903
1904                         if ( $wgContentHandlerUseDB ) {
1905                                 $row['content_model'] = $current->rev_content_model;
1906                                 $row['content_format'] = $current->rev_content_format;
1907                         }
1908
1909                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1910
1911                         $revision = new Revision( $row );
1912                 } else {
1913                         $revision = null;
1914                 }
1915
1916                 return $revision;
1917         }
1918
1919         /**
1920          * Determine if the current user is allowed to view a particular
1921          * field of this revision, if it's marked as deleted.
1922          *
1923          * @param int $field One of self::DELETED_TEXT,
1924          *                              self::DELETED_COMMENT,
1925          *                              self::DELETED_USER
1926          * @param User|null $user User object to check, or null to use $wgUser
1927          * @return bool
1928          */
1929         public function userCan( $field, User $user = null ) {
1930                 return self::userCanBitfield( $this->getVisibility(), $field, $user );
1931         }
1932
1933         /**
1934          * Determine if the current user is allowed to view a particular
1935          * field of this revision, if it's marked as deleted. This is used
1936          * by various classes to avoid duplication.
1937          *
1938          * @param int $bitfield Current field
1939          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1940          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1941          *                               self::DELETED_USER = File::DELETED_USER
1942          * @param User|null $user User object to check, or null to use $wgUser
1943          * @param Title|null $title A Title object to check for per-page restrictions on,
1944          *                          instead of just plain userrights
1945          * @return bool
1946          */
1947         public static function userCanBitfield( $bitfield, $field, User $user = null,
1948                 Title $title = null
1949         ) {
1950                 if ( $bitfield & $field ) { // aspect is deleted
1951                         if ( $user === null ) {
1952                                 global $wgUser;
1953                                 $user = $wgUser;
1954                         }
1955                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1956                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1957                         } elseif ( $field & self::DELETED_TEXT ) {
1958                                 $permissions = [ 'deletedtext' ];
1959                         } else {
1960                                 $permissions = [ 'deletedhistory' ];
1961                         }
1962                         $permissionlist = implode( ', ', $permissions );
1963                         if ( $title === null ) {
1964                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1965                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1966                         } else {
1967                                 $text = $title->getPrefixedText();
1968                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1969                                 foreach ( $permissions as $perm ) {
1970                                         if ( $title->userCan( $perm, $user ) ) {
1971                                                 return true;
1972                                         }
1973                                 }
1974                                 return false;
1975                         }
1976                 } else {
1977                         return true;
1978                 }
1979         }
1980
1981         /**
1982          * Get rev_timestamp from rev_id, without loading the rest of the row
1983          *
1984          * @param Title $title
1985          * @param int $id
1986          * @param int $flags
1987          * @return string|bool False if not found
1988          */
1989         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1990                 $db = ( $flags & self::READ_LATEST )
1991                         ? wfGetDB( DB_MASTER )
1992                         : wfGetDB( DB_REPLICA );
1993                 // Casting fix for databases that can't take '' for rev_id
1994                 if ( $id == '' ) {
1995                         $id = 0;
1996                 }
1997                 $conds = [ 'rev_id' => $id ];
1998                 $conds['rev_page'] = $title->getArticleID();
1999                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
2000
2001                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
2002         }
2003
2004         /**
2005          * Get count of revisions per page...not very efficient
2006          *
2007          * @param IDatabase $db
2008          * @param int $id Page id
2009          * @return int
2010          */
2011         static function countByPageId( $db, $id ) {
2012                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
2013                         [ 'rev_page' => $id ], __METHOD__ );
2014                 if ( $row ) {
2015                         return $row->revCount;
2016                 }
2017                 return 0;
2018         }
2019
2020         /**
2021          * Get count of revisions per page...not very efficient
2022          *
2023          * @param IDatabase $db
2024          * @param Title $title
2025          * @return int
2026          */
2027         static function countByTitle( $db, $title ) {
2028                 $id = $title->getArticleID();
2029                 if ( $id ) {
2030                         return self::countByPageId( $db, $id );
2031                 }
2032                 return 0;
2033         }
2034
2035         /**
2036          * Check if no edits were made by other users since
2037          * the time a user started editing the page. Limit to
2038          * 50 revisions for the sake of performance.
2039          *
2040          * @since 1.20
2041          * @deprecated since 1.24
2042          *
2043          * @param IDatabase|int $db The Database to perform the check on. May be given as a
2044          *        Database object or a database identifier usable with wfGetDB.
2045          * @param int $pageId The ID of the page in question
2046          * @param int $userId The ID of the user in question
2047          * @param string $since Look at edits since this time
2048          *
2049          * @return bool True if the given user was the only one to edit since the given timestamp
2050          */
2051         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
2052                 if ( !$userId ) {
2053                         return false;
2054                 }
2055
2056                 if ( is_int( $db ) ) {
2057                         $db = wfGetDB( $db );
2058                 }
2059
2060                 $res = $db->select( 'revision',
2061                         'rev_user',
2062                         [
2063                                 'rev_page' => $pageId,
2064                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
2065                         ],
2066                         __METHOD__,
2067                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
2068                 foreach ( $res as $row ) {
2069                         if ( $row->rev_user != $userId ) {
2070                                 return false;
2071                         }
2072                 }
2073                 return true;
2074         }
2075
2076         /**
2077          * Load a revision based on a known page ID and current revision ID from the DB
2078          *
2079          * This method allows for the use of caching, though accessing anything that normally
2080          * requires permission checks (aside from the text) will trigger a small DB lookup.
2081          * The title will also be lazy loaded, though setTitle() can be used to preload it.
2082          *
2083          * @param IDatabase $db
2084          * @param int $pageId Page ID
2085          * @param int $revId Known current revision of this page
2086          * @return Revision|bool Returns false if missing
2087          * @since 1.28
2088          */
2089         public static function newKnownCurrent( IDatabase $db, $pageId, $revId ) {
2090                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
2091                 return $cache->getWithSetCallback(
2092                         // Page/rev IDs passed in from DB to reflect history merges
2093                         $cache->makeGlobalKey( 'revision', $db->getDomainID(), $pageId, $revId ),
2094                         $cache::TTL_WEEK,
2095                         function ( $curValue, &$ttl, array &$setOpts ) use ( $db, $pageId, $revId ) {
2096                                 $setOpts += Database::getCacheSetOptions( $db );
2097
2098                                 $rev = Revision::loadFromPageId( $db, $pageId, $revId );
2099                                 // Reflect revision deletion and user renames
2100                                 if ( $rev ) {
2101                                         $rev->mTitle = null; // mutable; lazy-load
2102                                         $rev->mRefreshMutableFields = true;
2103                                 }
2104
2105                                 return $rev ?: false; // don't cache negatives
2106                         }
2107                 );
2108         }
2109
2110         /**
2111          * For cached revisions, make sure the user name and rev_deleted is up-to-date
2112          */
2113         private function loadMutableFields() {
2114                 if ( !$this->mRefreshMutableFields ) {
2115                         return; // not needed
2116                 }
2117
2118                 $this->mRefreshMutableFields = false;
2119                 $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
2120                 $row = $dbr->selectRow(
2121                         [ 'revision', 'user' ],
2122                         [ 'rev_deleted', 'user_name' ],
2123                         [ 'rev_id' => $this->mId, 'user_id = rev_user' ],
2124                         __METHOD__
2125                 );
2126                 if ( $row ) { // update values
2127                         $this->mDeleted = (int)$row->rev_deleted;
2128                         $this->mUserText = $row->user_name;
2129                 }
2130         }
2131 }