includes/Revision.php

   1 <?php
   2 /**
   3  * Representation of a page version.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22 use MediaWiki\Linker\LinkTarget;
  23
  24 /**
  25  * @todo document
  26  */
  27 class Revision implements IDBAccessObject {
  28         /** @var int|null */
  29         protected $mId;
  30         /** @var int|null */
  31         protected $mPage;
  32         /** @var string */
  33         protected $mUserText;
  34         /** @var string */
  35         protected $mOrigUserText;
  36         /** @var int */
  37         protected $mUser;
  38         /** @var bool */
  39         protected $mMinorEdit;
  40         /** @var string */
  41         protected $mTimestamp;
  42         /** @var int */
  43         protected $mDeleted;
  44         /** @var int */
  45         protected $mSize;
  46         /** @var string */
  47         protected $mSha1;
  48         /** @var int */
  49         protected $mParentId;
  50         /** @var string */
  51         protected $mComment;
  52         /** @var string */
  53         protected $mText;
  54         /** @var int */
  55         protected $mTextId;
  56         /** @var int */
  57         protected $mUnpatrolled;
  58
  59         /** @var stdClass|null */
  60         protected $mTextRow;
  61
  62         /**  @var null|Title */
  63         protected $mTitle;
  64         /** @var bool */
  65         protected $mCurrent;
  66         /** @var string */
  67         protected $mContentModel;
  68         /** @var string */
  69         protected $mContentFormat;
  70
  71         /** @var Content|null|bool */
  72         protected $mContent;
  73         /** @var null|ContentHandler */
  74         protected $mContentHandler;
  75
  76         /** @var int */
  77         protected $mQueryFlags = 0;
  78         /** @var bool Used for cached values to reload user text and rev_deleted */
  79         protected $mRefreshMutableFields = false;
  80         /** @var string Wiki ID; false means the current wiki */
  81         protected $mWiki = false;
  82
  83         // Revision deletion constants
  84         const DELETED_TEXT = 1;
  85         const DELETED_COMMENT = 2;
  86         const DELETED_USER = 4;
  87         const DELETED_RESTRICTED = 8;
  88         const SUPPRESSED_USER = 12; // convenience
  89
  90         // Audience options for accessors
  91         const FOR_PUBLIC = 1;
  92         const FOR_THIS_USER = 2;
  93         const RAW = 3;
  94
  95         /**
  96          * Load a page revision from a given revision ID number.
  97          * Returns null if no such revision can be found.
  98          *
  99          * $flags include:
 100          *      Revision::READ_LATEST  : Select the data from the master
 101          *      Revision::READ_LOCKING : Select & lock the data from the master
 102          *
 103          * @param int $id
 104          * @param int $flags (optional)
 105          * @return Revision|null
 106          */
 107         public static function newFromId( $id, $flags = 0 ) {
 108                 return self::newFromConds( [ 'rev_id' => intval( $id ) ], $flags );
 109         }
 110
 111         /**
 112          * Load either the current, or a specified, revision
 113          * that's attached to a given link target. If not attached
 114          * to that link target, will return null.
 115          *
 116          * $flags include:
 117          *      Revision::READ_LATEST  : Select the data from the master
 118          *      Revision::READ_LOCKING : Select & lock the data from the master
 119          *
 120          * @param LinkTarget $linkTarget
 121          * @param int $id (optional)
 122          * @param int $flags Bitfield (optional)
 123          * @return Revision|null
 124          */
 125         public static function newFromTitle( LinkTarget $linkTarget, $id = 0, $flags = 0 ) {
 126                 $conds = [
 127                         'page_namespace' => $linkTarget->getNamespace(),
 128                         'page_title' => $linkTarget->getDBkey()
 129                 ];
 130                 if ( $id ) {
 131                         // Use the specified ID
 132                         $conds['rev_id'] = $id;
 133                         return self::newFromConds( $conds, $flags );
 134                 } else {
 135                         // Use a join to get the latest revision
 136                         $conds[] = 'rev_id=page_latest';
 137                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 138                         return self::loadFromConds( $db, $conds, $flags );
 139                 }
 140         }
 141
 142         /**
 143          * Load either the current, or a specified, revision
 144          * that's attached to a given page ID.
 145          * Returns null if no such revision can be found.
 146          *
 147          * $flags include:
 148          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 149          *      Revision::READ_LOCKING : Select & lock the data from the master
 150          *
 151          * @param int $pageId
 152          * @param int $revId (optional)
 153          * @param int $flags Bitfield (optional)
 154          * @return Revision|null
 155          */
 156         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 157                 $conds = [ 'page_id' => $pageId ];
 158                 if ( $revId ) {
 159                         $conds['rev_id'] = $revId;
 160                         return self::newFromConds( $conds, $flags );
 161                 } else {
 162                         // Use a join to get the latest revision
 163                         $conds[] = 'rev_id = page_latest';
 164                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 165                         return self::loadFromConds( $db, $conds, $flags );
 166                 }
 167         }
 168
 169         /**
 170          * Make a fake revision object from an archive table row. This is queried
 171          * for permissions or even inserted (as in Special:Undelete)
 172          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 173          *
 174          * @param object $row
 175          * @param array $overrides
 176          *
 177          * @throws MWException
 178          * @return Revision
 179          */
 180         public static function newFromArchiveRow( $row, $overrides = [] ) {
 181                 global $wgContentHandlerUseDB;
 182
 183                 $attribs = $overrides + [
 184                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 185                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 186                         'comment'    => $row->ar_comment,
 187                         'user'       => $row->ar_user,
 188                         'user_text'  => $row->ar_user_text,
 189                         'timestamp'  => $row->ar_timestamp,
 190                         'minor_edit' => $row->ar_minor_edit,
 191                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 192                         'deleted'    => $row->ar_deleted,
 193                         'len'        => $row->ar_len,
 194                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 195                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 196                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 197                 ];
 198
 199                 if ( !$wgContentHandlerUseDB ) {
 200                         unset( $attribs['content_model'] );
 201                         unset( $attribs['content_format'] );
 202                 }
 203
 204                 if ( !isset( $attribs['title'] )
 205                         && isset( $row->ar_namespace )
 206                         && isset( $row->ar_title )
 207                 ) {
 208                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 209                 }
 210
 211                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 212                         // Pre-1.5 ar_text row
 213                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 214                         if ( $attribs['text'] === false ) {
 215                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 216                         }
 217                 }
 218                 return new self( $attribs );
 219         }
 220
 221         /**
 222          * @since 1.19
 223          *
 224          * @param object $row
 225          * @return Revision
 226          */
 227         public static function newFromRow( $row ) {
 228                 return new self( $row );
 229         }
 230
 231         /**
 232          * Load a page revision from a given revision ID number.
 233          * Returns null if no such revision can be found.
 234          *
 235          * @param IDatabase $db
 236          * @param int $id
 237          * @return Revision|null
 238          */
 239         public static function loadFromId( $db, $id ) {
 240                 return self::loadFromConds( $db, [ 'rev_id' => intval( $id ) ] );
 241         }
 242
 243         /**
 244          * Load either the current, or a specified, revision
 245          * that's attached to a given page. If not attached
 246          * to that page, will return null.
 247          *
 248          * @param IDatabase $db
 249          * @param int $pageid
 250          * @param int $id
 251          * @return Revision|null
 252          */
 253         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 254                 $conds = [ 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) ];
 255                 if ( $id ) {
 256                         $conds['rev_id'] = intval( $id );
 257                 } else {
 258                         $conds[] = 'rev_id=page_latest';
 259                 }
 260                 return self::loadFromConds( $db, $conds );
 261         }
 262
 263         /**
 264          * Load either the current, or a specified, revision
 265          * that's attached to a given page. If not attached
 266          * to that page, will return null.
 267          *
 268          * @param IDatabase $db
 269          * @param Title $title
 270          * @param int $id
 271          * @return Revision|null
 272          */
 273         public static function loadFromTitle( $db, $title, $id = 0 ) {
 274                 if ( $id ) {
 275                         $matchId = intval( $id );
 276                 } else {
 277                         $matchId = 'page_latest';
 278                 }
 279                 return self::loadFromConds( $db,
 280                         [
 281                                 "rev_id=$matchId",
 282                                 'page_namespace' => $title->getNamespace(),
 283                                 'page_title' => $title->getDBkey()
 284                         ]
 285                 );
 286         }
 287
 288         /**
 289          * Load the revision for the given title with the given timestamp.
 290          * WARNING: Timestamps may in some circumstances not be unique,
 291          * so this isn't the best key to use.
 292          *
 293          * @param IDatabase $db
 294          * @param Title $title
 295          * @param string $timestamp
 296          * @return Revision|null
 297          */
 298         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 299                 return self::loadFromConds( $db,
 300                         [
 301                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 302                                 'page_namespace' => $title->getNamespace(),
 303                                 'page_title' => $title->getDBkey()
 304                         ]
 305                 );
 306         }
 307
 308         /**
 309          * Given a set of conditions, fetch a revision
 310          *
 311          * This method is used then a revision ID is qualified and
 312          * will incorporate some basic replica DB/master fallback logic
 313          *
 314          * @param array $conditions
 315          * @param int $flags (optional)
 316          * @return Revision|null
 317          */
 318         private static function newFromConds( $conditions, $flags = 0 ) {
 319                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_REPLICA );
 320
 321                 $rev = self::loadFromConds( $db, $conditions, $flags );
 322                 // Make sure new pending/committed revision are visibile later on
 323                 // within web requests to certain avoid bugs like T93866 and T94407.
 324                 if ( !$rev
 325                         && !( $flags & self::READ_LATEST )
 326                         && wfGetLB()->getServerCount() > 1
 327                         && wfGetLB()->hasOrMadeRecentMasterChanges()
 328                 ) {
 329                         $flags = self::READ_LATEST;
 330                         $db = wfGetDB( DB_MASTER );
 331                         $rev = self::loadFromConds( $db, $conditions, $flags );
 332                 }
 333
 334                 if ( $rev ) {
 335                         $rev->mQueryFlags = $flags;
 336                 }
 337
 338                 return $rev;
 339         }
 340
 341         /**
 342          * Given a set of conditions, fetch a revision from
 343          * the given database connection.
 344          *
 345          * @param IDatabase $db
 346          * @param array $conditions
 347          * @param int $flags (optional)
 348          * @return Revision|null
 349          */
 350         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 351                 $row = self::fetchFromConds( $db, $conditions, $flags );
 352                 if ( $row ) {
 353                         $rev = new Revision( $row );
 354                         $rev->mWiki = $db->getWikiID();
 355
 356                         return $rev;
 357                 }
 358
 359                 return null;
 360         }
 361
 362         /**
 363          * Return a wrapper for a series of database rows to
 364          * fetch all of a given page's revisions in turn.
 365          * Each row can be fed to the constructor to get objects.
 366          *
 367          * @param LinkTarget $title
 368          * @return ResultWrapper
 369          * @deprecated Since 1.28
 370          */
 371         public static function fetchRevision( LinkTarget $title ) {
 372                 $row = self::fetchFromConds(
 373                         wfGetDB( DB_REPLICA ),
 374                         [
 375                                 'rev_id=page_latest',
 376                                 'page_namespace' => $title->getNamespace(),
 377                                 'page_title' => $title->getDBkey()
 378                         ]
 379                 );
 380
 381                 return new FakeResultWrapper( $row ? [ $row ] : [] );
 382         }
 383
 384         /**
 385          * Given a set of conditions, return a ResultWrapper
 386          * which will return matching database rows with the
 387          * fields necessary to build Revision objects.
 388          *
 389          * @param IDatabase $db
 390          * @param array $conditions
 391          * @param int $flags (optional)
 392          * @return stdClass
 393          */
 394         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 395                 $fields = array_merge(
 396                         self::selectFields(),
 397                         self::selectPageFields(),
 398                         self::selectUserFields()
 399                 );
 400                 $options = [];
 401                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 402                         $options[] = 'FOR UPDATE';
 403                 }
 404                 return $db->selectRow(
 405                         [ 'revision', 'page', 'user' ],
 406                         $fields,
 407                         $conditions,
 408                         __METHOD__,
 409                         $options,
 410                         [ 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() ]
 411                 );
 412         }
 413
 414         /**
 415          * Return the value of a select() JOIN conds array for the user table.
 416          * This will get user table rows for logged-in users.
 417          * @since 1.19
 418          * @return array
 419          */
 420         public static function userJoinCond() {
 421                 return [ 'LEFT JOIN', [ 'rev_user != 0', 'user_id = rev_user' ] ];
 422         }
 423
 424         /**
 425          * Return the value of a select() page conds array for the page table.
 426          * This will assure that the revision(s) are not orphaned from live pages.
 427          * @since 1.19
 428          * @return array
 429          */
 430         public static function pageJoinCond() {
 431                 return [ 'INNER JOIN', [ 'page_id = rev_page' ] ];
 432         }
 433
 434         /**
 435          * Return the list of revision fields that should be selected to create
 436          * a new revision.
 437          * @return array
 438          */
 439         public static function selectFields() {
 440                 global $wgContentHandlerUseDB;
 441
 442                 $fields = [
 443                         'rev_id',
 444                         'rev_page',
 445                         'rev_text_id',
 446                         'rev_timestamp',
 447                         'rev_comment',
 448                         'rev_user_text',
 449                         'rev_user',
 450                         'rev_minor_edit',
 451                         'rev_deleted',
 452                         'rev_len',
 453                         'rev_parent_id',
 454                         'rev_sha1',
 455                 ];
 456
 457                 if ( $wgContentHandlerUseDB ) {
 458                         $fields[] = 'rev_content_format';
 459                         $fields[] = 'rev_content_model';
 460                 }
 461
 462                 return $fields;
 463         }
 464
 465         /**
 466          * Return the list of revision fields that should be selected to create
 467          * a new revision from an archive row.
 468          * @return array
 469          */
 470         public static function selectArchiveFields() {
 471                 global $wgContentHandlerUseDB;
 472                 $fields = [
 473                         'ar_id',
 474                         'ar_page_id',
 475                         'ar_rev_id',
 476                         'ar_text',
 477                         'ar_text_id',
 478                         'ar_timestamp',
 479                         'ar_comment',
 480                         'ar_user_text',
 481                         'ar_user',
 482                         'ar_minor_edit',
 483                         'ar_deleted',
 484                         'ar_len',
 485                         'ar_parent_id',
 486                         'ar_sha1',
 487                 ];
 488
 489                 if ( $wgContentHandlerUseDB ) {
 490                         $fields[] = 'ar_content_format';
 491                         $fields[] = 'ar_content_model';
 492                 }
 493                 return $fields;
 494         }
 495
 496         /**
 497          * Return the list of text fields that should be selected to read the
 498          * revision text
 499          * @return array
 500          */
 501         public static function selectTextFields() {
 502                 return [
 503                         'old_text',
 504                         'old_flags'
 505                 ];
 506         }
 507
 508         /**
 509          * Return the list of page fields that should be selected from page table
 510          * @return array
 511          */
 512         public static function selectPageFields() {
 513                 return [
 514                         'page_namespace',
 515                         'page_title',
 516                         'page_id',
 517                         'page_latest',
 518                         'page_is_redirect',
 519                         'page_len',
 520                 ];
 521         }
 522
 523         /**
 524          * Return the list of user fields that should be selected from user table
 525          * @return array
 526          */
 527         public static function selectUserFields() {
 528                 return [ 'user_name' ];
 529         }
 530
 531         /**
 532          * Do a batched query to get the parent revision lengths
 533          * @param IDatabase $db
 534          * @param array $revIds
 535          * @return array
 536          */
 537         public static function getParentLengths( $db, array $revIds ) {
 538                 $revLens = [];
 539                 if ( !$revIds ) {
 540                         return $revLens; // empty
 541                 }
 542                 $res = $db->select( 'revision',
 543                         [ 'rev_id', 'rev_len' ],
 544                         [ 'rev_id' => $revIds ],
 545                         __METHOD__ );
 546                 foreach ( $res as $row ) {
 547                         $revLens[$row->rev_id] = $row->rev_len;
 548                 }
 549                 return $revLens;
 550         }
 551
 552         /**
 553          * Constructor
 554          *
 555          * @param object|array $row Either a database row or an array
 556          * @throws MWException
 557          * @access private
 558          */
 559         function __construct( $row ) {
 560                 if ( is_object( $row ) ) {
 561                         $this->mId = intval( $row->rev_id );
 562                         $this->mPage = intval( $row->rev_page );
 563                         $this->mTextId = intval( $row->rev_text_id );
 564                         $this->mComment = $row->rev_comment;
 565                         $this->mUser = intval( $row->rev_user );
 566                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 567                         $this->mTimestamp = $row->rev_timestamp;
 568                         $this->mDeleted = intval( $row->rev_deleted );
 569
 570                         if ( !isset( $row->rev_parent_id ) ) {
 571                                 $this->mParentId = null;
 572                         } else {
 573                                 $this->mParentId = intval( $row->rev_parent_id );
 574                         }
 575
 576                         if ( !isset( $row->rev_len ) ) {
 577                                 $this->mSize = null;
 578                         } else {
 579                                 $this->mSize = intval( $row->rev_len );
 580                         }
 581
 582                         if ( !isset( $row->rev_sha1 ) ) {
 583                                 $this->mSha1 = null;
 584                         } else {
 585                                 $this->mSha1 = $row->rev_sha1;
 586                         }
 587
 588                         if ( isset( $row->page_latest ) ) {
 589                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 590                                 $this->mTitle = Title::newFromRow( $row );
 591                         } else {
 592                                 $this->mCurrent = false;
 593                                 $this->mTitle = null;
 594                         }
 595
 596                         if ( !isset( $row->rev_content_model ) ) {
 597                                 $this->mContentModel = null; # determine on demand if needed
 598                         } else {
 599                                 $this->mContentModel = strval( $row->rev_content_model );
 600                         }
 601
 602                         if ( !isset( $row->rev_content_format ) ) {
 603                                 $this->mContentFormat = null; # determine on demand if needed
 604                         } else {
 605                                 $this->mContentFormat = strval( $row->rev_content_format );
 606                         }
 607
 608                         // Lazy extraction...
 609                         $this->mText = null;
 610                         if ( isset( $row->old_text ) ) {
 611                                 $this->mTextRow = $row;
 612                         } else {
 613                                 // 'text' table row entry will be lazy-loaded
 614                                 $this->mTextRow = null;
 615                         }
 616
 617                         // Use user_name for users and rev_user_text for IPs...
 618                         $this->mUserText = null; // lazy load if left null
 619                         if ( $this->mUser == 0 ) {
 620                                 $this->mUserText = $row->rev_user_text; // IP user
 621                         } elseif ( isset( $row->user_name ) ) {
 622                                 $this->mUserText = $row->user_name; // logged-in user
 623                         }
 624                         $this->mOrigUserText = $row->rev_user_text;
 625                 } elseif ( is_array( $row ) ) {
 626                         // Build a new revision to be saved...
 627                         global $wgUser; // ugh
 628
 629                         # if we have a content object, use it to set the model and type
 630                         if ( !empty( $row['content'] ) ) {
 631                                 // @todo when is that set? test with external store setup! check out insertOn() [dk]
 632                                 if ( !empty( $row['text_id'] ) ) {
 633                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 634                                                 "can't serialize content object" );
 635                                 }
 636
 637                                 $row['content_model'] = $row['content']->getModel();
 638                                 # note: mContentFormat is initializes later accordingly
 639                                 # note: content is serialized later in this method!
 640                                 # also set text to null?
 641                         }
 642
 643                         $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 644                         $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 645                         $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 646                         $this->mUserText = isset( $row['user_text'] )
 647                                 ? strval( $row['user_text'] ) : $wgUser->getName();
 648                         $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 649                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 650                         $this->mTimestamp = isset( $row['timestamp'] )
 651                                 ? strval( $row['timestamp'] ) : wfTimestampNow();
 652                         $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 653                         $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 654                         $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 655                         $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 656
 657                         $this->mContentModel = isset( $row['content_model'] )
 658                                 ? strval( $row['content_model'] ) : null;
 659                         $this->mContentFormat = isset( $row['content_format'] )
 660                                 ? strval( $row['content_format'] ) : null;
 661
 662                         // Enforce spacing trimming on supplied text
 663                         $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 664                         $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 665                         $this->mTextRow = null;
 666
 667                         $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 668
 669                         // if we have a Content object, override mText and mContentModel
 670                         if ( !empty( $row['content'] ) ) {
 671                                 if ( !( $row['content'] instanceof Content ) ) {
 672                                         throw new MWException( '`content` field must contain a Content object.' );
 673                                 }
 674
 675                                 $handler = $this->getContentHandler();
 676                                 $this->mContent = $row['content'];
 677
 678                                 $this->mContentModel = $this->mContent->getModel();
 679                                 $this->mContentHandler = null;
 680
 681                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 682                         } elseif ( $this->mText !== null ) {
 683                                 $handler = $this->getContentHandler();
 684                                 $this->mContent = $handler->unserializeContent( $this->mText );
 685                         }
 686
 687                         // If we have a Title object, make sure it is consistent with mPage.
 688                         if ( $this->mTitle && $this->mTitle->exists() ) {
 689                                 if ( $this->mPage === null ) {
 690                                         // if the page ID wasn't known, set it now
 691                                         $this->mPage = $this->mTitle->getArticleID();
 692                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 693                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 694                                         // but it seems worth mentioning it in the log.
 695                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 696                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 697                                 }
 698                         }
 699
 700                         $this->mCurrent = false;
 701
 702                         // If we still have no length, see it we have the text to figure it out
 703                         if ( !$this->mSize && $this->mContent !== null ) {
 704                                 $this->mSize = $this->mContent->getSize();
 705                         }
 706
 707                         // Same for sha1
 708                         if ( $this->mSha1 === null ) {
 709                                 $this->mSha1 = $this->mText === null ? null : self::base36Sha1( $this->mText );
 710                         }
 711
 712                         // force lazy init
 713                         $this->getContentModel();
 714                         $this->getContentFormat();
 715                 } else {
 716                         throw new MWException( 'Revision constructor passed invalid row format.' );
 717                 }
 718                 $this->mUnpatrolled = null;
 719         }
 720
 721         /**
 722          * Get revision ID
 723          *
 724          * @return int|null
 725          */
 726         public function getId() {
 727                 return $this->mId;
 728         }
 729
 730         /**
 731          * Set the revision ID
 732          *
 733          * This should only be used for proposed revisions that turn out to be null edits
 734          *
 735          * @since 1.19
 736          * @param int $id
 737          */
 738         public function setId( $id ) {
 739                 $this->mId = (int)$id;
 740         }
 741
 742         /**
 743          * Set the user ID/name
 744          *
 745          * This should only be used for proposed revisions that turn out to be null edits
 746          *
 747          * @since 1.28
 748          * @param integer $id User ID
 749          * @param string $name User name
 750          */
 751         public function setUserIdAndName( $id, $name ) {
 752                 $this->mUser = (int)$id;
 753                 $this->mUserText = $name;
 754                 $this->mOrigUserText = $name;
 755         }
 756
 757         /**
 758          * Get text row ID
 759          *
 760          * @return int|null
 761          */
 762         public function getTextId() {
 763                 return $this->mTextId;
 764         }
 765
 766         /**
 767          * Get parent revision ID (the original previous page revision)
 768          *
 769          * @return int|null
 770          */
 771         public function getParentId() {
 772                 return $this->mParentId;
 773         }
 774
 775         /**
 776          * Returns the length of the text in this revision, or null if unknown.
 777          *
 778          * @return int|null
 779          */
 780         public function getSize() {
 781                 return $this->mSize;
 782         }
 783
 784         /**
 785          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 786          *
 787          * @return string|null
 788          */
 789         public function getSha1() {
 790                 return $this->mSha1;
 791         }
 792
 793         /**
 794          * Returns the title of the page associated with this entry or null.
 795          *
 796          * Will do a query, when title is not set and id is given.
 797          *
 798          * @return Title|null
 799          */
 800         public function getTitle() {
 801                 if ( $this->mTitle !== null ) {
 802                         return $this->mTitle;
 803                 }
 804                 // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 805                 if ( $this->mId !== null ) {
 806                         $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
 807                         $row = $dbr->selectRow(
 808                                 [ 'page', 'revision' ],
 809                                 self::selectPageFields(),
 810                                 [ 'page_id=rev_page', 'rev_id' => $this->mId ],
 811                                 __METHOD__
 812                         );
 813                         if ( $row ) {
 814                                 // @TODO: better foreign title handling
 815                                 $this->mTitle = Title::newFromRow( $row );
 816                         }
 817                 }
 818
 819                 if ( $this->mWiki === false || $this->mWiki === wfWikiID() ) {
 820                         // Loading by ID is best, though not possible for foreign titles
 821                         if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 822                                 $this->mTitle = Title::newFromID( $this->mPage );
 823                         }
 824                 }
 825
 826                 return $this->mTitle;
 827         }
 828
 829         /**
 830          * Set the title of the revision
 831          *
 832          * @param Title $title
 833          */
 834         public function setTitle( $title ) {
 835                 $this->mTitle = $title;
 836         }
 837
 838         /**
 839          * Get the page ID
 840          *
 841          * @return int|null
 842          */
 843         public function getPage() {
 844                 return $this->mPage;
 845         }
 846
 847         /**
 848          * Fetch revision's user id if it's available to the specified audience.
 849          * If the specified audience does not have access to it, zero will be
 850          * returned.
 851          *
 852          * @param int $audience One of:
 853          *   Revision::FOR_PUBLIC       to be displayed to all users
 854          *   Revision::FOR_THIS_USER    to be displayed to the given user
 855          *   Revision::RAW              get the ID regardless of permissions
 856          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 857          *   to the $audience parameter
 858          * @return int
 859          */
 860         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 861                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 862                         return 0;
 863                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 864                         return 0;
 865                 } else {
 866                         return $this->mUser;
 867                 }
 868         }
 869
 870         /**
 871          * Fetch revision's user id without regard for the current user's permissions
 872          *
 873          * @return string
 874          * @deprecated since 1.25, use getUser( Revision::RAW )
 875          */
 876         public function getRawUser() {
 877                 wfDeprecated( __METHOD__, '1.25' );
 878                 return $this->getUser( self::RAW );
 879         }
 880
 881         /**
 882          * Fetch revision's username if it's available to the specified audience.
 883          * If the specified audience does not have access to the username, an
 884          * empty string will be returned.
 885          *
 886          * @param int $audience One of:
 887          *   Revision::FOR_PUBLIC       to be displayed to all users
 888          *   Revision::FOR_THIS_USER    to be displayed to the given user
 889          *   Revision::RAW              get the text regardless of permissions
 890          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 891          *   to the $audience parameter
 892          * @return string
 893          */
 894         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 895                 $this->loadMutableFields();
 896
 897                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 898                         return '';
 899                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 900                         return '';
 901                 } else {
 902                         if ( $this->mUserText === null ) {
 903                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 904                                 if ( $this->mUserText === false ) {
 905                                         # This shouldn't happen, but it can if the wiki was recovered
 906                                         # via importing revs and there is no user table entry yet.
 907                                         $this->mUserText = $this->mOrigUserText;
 908                                 }
 909                         }
 910                         return $this->mUserText;
 911                 }
 912         }
 913
 914         /**
 915          * Fetch revision's username without regard for view restrictions
 916          *
 917          * @return string
 918          * @deprecated since 1.25, use getUserText( Revision::RAW )
 919          */
 920         public function getRawUserText() {
 921                 wfDeprecated( __METHOD__, '1.25' );
 922                 return $this->getUserText( self::RAW );
 923         }
 924
 925         /**
 926          * Fetch revision comment if it's available to the specified audience.
 927          * If the specified audience does not have access to the comment, an
 928          * empty string will be returned.
 929          *
 930          * @param int $audience One of:
 931          *   Revision::FOR_PUBLIC       to be displayed to all users
 932          *   Revision::FOR_THIS_USER    to be displayed to the given user
 933          *   Revision::RAW              get the text regardless of permissions
 934          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 935          *   to the $audience parameter
 936          * @return string
 937          */
 938         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 939                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 940                         return '';
 941                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 942                         return '';
 943                 } else {
 944                         return $this->mComment;
 945                 }
 946         }
 947
 948         /**
 949          * Fetch revision comment without regard for the current user's permissions
 950          *
 951          * @return string
 952          * @deprecated since 1.25, use getComment( Revision::RAW )
 953          */
 954         public function getRawComment() {
 955                 wfDeprecated( __METHOD__, '1.25' );
 956                 return $this->getComment( self::RAW );
 957         }
 958
 959         /**
 960          * @return bool
 961          */
 962         public function isMinor() {
 963                 return (bool)$this->mMinorEdit;
 964         }
 965
 966         /**
 967          * @return int Rcid of the unpatrolled row, zero if there isn't one
 968          */
 969         public function isUnpatrolled() {
 970                 if ( $this->mUnpatrolled !== null ) {
 971                         return $this->mUnpatrolled;
 972                 }
 973                 $rc = $this->getRecentChange();
 974                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 975                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 976                 } else {
 977                         $this->mUnpatrolled = 0;
 978                 }
 979                 return $this->mUnpatrolled;
 980         }
 981
 982         /**
 983          * Get the RC object belonging to the current revision, if there's one
 984          *
 985          * @param int $flags (optional) $flags include:
 986          *      Revision::READ_LATEST  : Select the data from the master
 987          *
 988          * @since 1.22
 989          * @return RecentChange|null
 990          */
 991         public function getRecentChange( $flags = 0 ) {
 992                 $dbr = wfGetDB( DB_REPLICA );
 993
 994                 list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
 995
 996                 return RecentChange::newFromConds(
 997                         [
 998                                 'rc_user_text' => $this->getUserText( Revision::RAW ),
 999                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
1000                                 'rc_this_oldid' => $this->getId()
1001                         ],
1002                         __METHOD__,
1003                         $dbType
1004                 );
1005         }
1006
1007         /**
1008          * @param int $field One of DELETED_* bitfield constants
1009          *
1010          * @return bool
1011          */
1012         public function isDeleted( $field ) {
1013                 if ( $this->isCurrent() && $field === self::DELETED_TEXT ) {
1014                         // Current revisions of pages cannot have the content hidden. Skipping this
1015                         // check is very useful for Parser as it fetches templates using newKnownCurrent().
1016                         // Calling getVisibility() in that case triggers a verification database query.
1017                         return false; // no need to check
1018                 }
1019
1020                 return ( $this->getVisibility() & $field ) == $field;
1021         }
1022
1023         /**
1024          * Get the deletion bitfield of the revision
1025          *
1026          * @return int
1027          */
1028         public function getVisibility() {
1029                 $this->loadMutableFields();
1030
1031                 return (int)$this->mDeleted;
1032         }
1033
1034         /**
1035          * Fetch revision text if it's available to the specified audience.
1036          * If the specified audience does not have the ability to view this
1037          * revision, an empty string will be returned.
1038          *
1039          * @param int $audience One of:
1040          *   Revision::FOR_PUBLIC       to be displayed to all users
1041          *   Revision::FOR_THIS_USER    to be displayed to the given user
1042          *   Revision::RAW              get the text regardless of permissions
1043          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1044          *   to the $audience parameter
1045          *
1046          * @deprecated since 1.21, use getContent() instead
1047          * @todo Replace usage in core
1048          * @return string
1049          */
1050         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
1051                 ContentHandler::deprecated( __METHOD__, '1.21' );
1052
1053                 $content = $this->getContent( $audience, $user );
1054                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
1055         }
1056
1057         /**
1058          * Fetch revision content if it's available to the specified audience.
1059          * If the specified audience does not have the ability to view this
1060          * revision, null will be returned.
1061          *
1062          * @param int $audience One of:
1063          *   Revision::FOR_PUBLIC       to be displayed to all users
1064          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1065          *   Revision::RAW              get the text regardless of permissions
1066          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1067          *   to the $audience parameter
1068          * @since 1.21
1069          * @return Content|null
1070          */
1071         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1072                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1073                         return null;
1074                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1075                         return null;
1076                 } else {
1077                         return $this->getContentInternal();
1078                 }
1079         }
1080
1081         /**
1082          * Get original serialized data (without checking view restrictions)
1083          *
1084          * @since 1.21
1085          * @return string
1086          */
1087         public function getSerializedData() {
1088                 if ( $this->mText === null ) {
1089                         // Revision is immutable. Load on demand.
1090                         $this->mText = $this->loadText();
1091                 }
1092
1093                 return $this->mText;
1094         }
1095
1096         /**
1097          * Gets the content object for the revision (or null on failure).
1098          *
1099          * Note that for mutable Content objects, each call to this method will return a
1100          * fresh clone.
1101          *
1102          * @since 1.21
1103          * @return Content|null The Revision's content, or null on failure.
1104          */
1105         protected function getContentInternal() {
1106                 if ( $this->mContent === null ) {
1107                         $text = $this->getSerializedData();
1108
1109                         if ( $text !== null && $text !== false ) {
1110                                 // Unserialize content
1111                                 $handler = $this->getContentHandler();
1112                                 $format = $this->getContentFormat();
1113
1114                                 $this->mContent = $handler->unserializeContent( $text, $format );
1115                         }
1116                 }
1117
1118                 // NOTE: copy() will return $this for immutable content objects
1119                 return $this->mContent ? $this->mContent->copy() : null;
1120         }
1121
1122         /**
1123          * Returns the content model for this revision.
1124          *
1125          * If no content model was stored in the database, the default content model for the title is
1126          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1127          * is used as a last resort.
1128          *
1129          * @return string The content model id associated with this revision,
1130          *     see the CONTENT_MODEL_XXX constants.
1131          **/
1132         public function getContentModel() {
1133                 if ( !$this->mContentModel ) {
1134                         $title = $this->getTitle();
1135                         if ( $title ) {
1136                                 $this->mContentModel = ContentHandler::getDefaultModelFor( $title );
1137                         } else {
1138                                 $this->mContentModel = CONTENT_MODEL_WIKITEXT;
1139                         }
1140
1141                         assert( !empty( $this->mContentModel ) );
1142                 }
1143
1144                 return $this->mContentModel;
1145         }
1146
1147         /**
1148          * Returns the content format for this revision.
1149          *
1150          * If no content format was stored in the database, the default format for this
1151          * revision's content model is returned.
1152          *
1153          * @return string The content format id associated with this revision,
1154          *     see the CONTENT_FORMAT_XXX constants.
1155          **/
1156         public function getContentFormat() {
1157                 if ( !$this->mContentFormat ) {
1158                         $handler = $this->getContentHandler();
1159                         $this->mContentFormat = $handler->getDefaultFormat();
1160
1161                         assert( !empty( $this->mContentFormat ) );
1162                 }
1163
1164                 return $this->mContentFormat;
1165         }
1166
1167         /**
1168          * Returns the content handler appropriate for this revision's content model.
1169          *
1170          * @throws MWException
1171          * @return ContentHandler
1172          */
1173         public function getContentHandler() {
1174                 if ( !$this->mContentHandler ) {
1175                         $model = $this->getContentModel();
1176                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1177
1178                         $format = $this->getContentFormat();
1179
1180                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1181                                 throw new MWException( "Oops, the content format $format is not supported for "
1182                                         . "this content model, $model" );
1183                         }
1184                 }
1185
1186                 return $this->mContentHandler;
1187         }
1188
1189         /**
1190          * @return string
1191          */
1192         public function getTimestamp() {
1193                 return wfTimestamp( TS_MW, $this->mTimestamp );
1194         }
1195
1196         /**
1197          * @return bool
1198          */
1199         public function isCurrent() {
1200                 return $this->mCurrent;
1201         }
1202
1203         /**
1204          * Get previous revision for this title
1205          *
1206          * @return Revision|null
1207          */
1208         public function getPrevious() {
1209                 if ( $this->getTitle() ) {
1210                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1211                         if ( $prev ) {
1212                                 return self::newFromTitle( $this->getTitle(), $prev );
1213                         }
1214                 }
1215                 return null;
1216         }
1217
1218         /**
1219          * Get next revision for this title
1220          *
1221          * @return Revision|null
1222          */
1223         public function getNext() {
1224                 if ( $this->getTitle() ) {
1225                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1226                         if ( $next ) {
1227                                 return self::newFromTitle( $this->getTitle(), $next );
1228                         }
1229                 }
1230                 return null;
1231         }
1232
1233         /**
1234          * Get previous revision Id for this page_id
1235          * This is used to populate rev_parent_id on save
1236          *
1237          * @param IDatabase $db
1238          * @return int
1239          */
1240         private function getPreviousRevisionId( $db ) {
1241                 if ( $this->mPage === null ) {
1242                         return 0;
1243                 }
1244                 # Use page_latest if ID is not given
1245                 if ( !$this->mId ) {
1246                         $prevId = $db->selectField( 'page', 'page_latest',
1247                                 [ 'page_id' => $this->mPage ],
1248                                 __METHOD__ );
1249                 } else {
1250                         $prevId = $db->selectField( 'revision', 'rev_id',
1251                                 [ 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ],
1252                                 __METHOD__,
1253                                 [ 'ORDER BY' => 'rev_id DESC' ] );
1254                 }
1255                 return intval( $prevId );
1256         }
1257
1258         /**
1259          * Get revision text associated with an old or archive row
1260          * $row is usually an object from wfFetchRow(), both the flags and the text
1261          * field must be included.
1262          *
1263          * @param stdClass $row The text data
1264          * @param string $prefix Table prefix (default 'old_')
1265          * @param string|bool $wiki The name of the wiki to load the revision text from
1266          *   (same as the the wiki $row was loaded from) or false to indicate the local
1267          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1268          *   identifier as understood by the LoadBalancer class.
1269          * @return string Text the text requested or false on failure
1270          */
1271         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1272
1273                 # Get data
1274                 $textField = $prefix . 'text';
1275                 $flagsField = $prefix . 'flags';
1276
1277                 if ( isset( $row->$flagsField ) ) {
1278                         $flags = explode( ',', $row->$flagsField );
1279                 } else {
1280                         $flags = [];
1281                 }
1282
1283                 if ( isset( $row->$textField ) ) {
1284                         $text = $row->$textField;
1285                 } else {
1286                         return false;
1287                 }
1288
1289                 # Use external methods for external objects, text in table is URL-only then
1290                 if ( in_array( 'external', $flags ) ) {
1291                         $url = $text;
1292                         $parts = explode( '://', $url, 2 );
1293                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1294                                 return false;
1295                         }
1296                         $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
1297                 }
1298
1299                 // If the text was fetched without an error, convert it
1300                 if ( $text !== false ) {
1301                         $text = self::decompressRevisionText( $text, $flags );
1302                 }
1303                 return $text;
1304         }
1305
1306         /**
1307          * If $wgCompressRevisions is enabled, we will compress data.
1308          * The input string is modified in place.
1309          * Return value is the flags field: contains 'gzip' if the
1310          * data is compressed, and 'utf-8' if we're saving in UTF-8
1311          * mode.
1312          *
1313          * @param mixed $text Reference to a text
1314          * @return string
1315          */
1316         public static function compressRevisionText( &$text ) {
1317                 global $wgCompressRevisions;
1318                 $flags = [];
1319
1320                 # Revisions not marked this way will be converted
1321                 # on load if $wgLegacyCharset is set in the future.
1322                 $flags[] = 'utf-8';
1323
1324                 if ( $wgCompressRevisions ) {
1325                         if ( function_exists( 'gzdeflate' ) ) {
1326                                 $deflated = gzdeflate( $text );
1327
1328                                 if ( $deflated === false ) {
1329                                         wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
1330                                 } else {
1331                                         $text = $deflated;
1332                                         $flags[] = 'gzip';
1333                                 }
1334                         } else {
1335                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1336                         }
1337                 }
1338                 return implode( ',', $flags );
1339         }
1340
1341         /**
1342          * Re-converts revision text according to it's flags.
1343          *
1344          * @param mixed $text Reference to a text
1345          * @param array $flags Compression flags
1346          * @return string|bool Decompressed text, or false on failure
1347          */
1348         public static function decompressRevisionText( $text, $flags ) {
1349                 if ( in_array( 'gzip', $flags ) ) {
1350                         # Deal with optional compression of archived pages.
1351                         # This can be done periodically via maintenance/compressOld.php, and
1352                         # as pages are saved if $wgCompressRevisions is set.
1353                         $text = gzinflate( $text );
1354
1355                         if ( $text === false ) {
1356                                 wfLogWarning( __METHOD__ . ': gzinflate() failed' );
1357                                 return false;
1358                         }
1359                 }
1360
1361                 if ( in_array( 'object', $flags ) ) {
1362                         # Generic compressed storage
1363                         $obj = unserialize( $text );
1364                         if ( !is_object( $obj ) ) {
1365                                 // Invalid object
1366                                 return false;
1367                         }
1368                         $text = $obj->getText();
1369                 }
1370
1371                 global $wgLegacyEncoding;
1372                 if ( $text !== false && $wgLegacyEncoding
1373                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1374                 ) {
1375                         # Old revisions kept around in a legacy encoding?
1376                         # Upconvert on demand.
1377                         # ("utf8" checked for compatibility with some broken
1378                         #  conversion scripts 2008-12-30)
1379                         global $wgContLang;
1380                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1381                 }
1382
1383                 return $text;
1384         }
1385
1386         /**
1387          * Insert a new revision into the database, returning the new revision ID
1388          * number on success and dies horribly on failure.
1389          *
1390          * @param IDatabase $dbw (master connection)
1391          * @throws MWException
1392          * @return int
1393          */
1394         public function insertOn( $dbw ) {
1395                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1396
1397                 // Not allowed to have rev_page equal to 0, false, etc.
1398                 if ( !$this->mPage ) {
1399                         $title = $this->getTitle();
1400                         if ( $title instanceof Title ) {
1401                                 $titleText = ' for page ' . $title->getPrefixedText();
1402                         } else {
1403                                 $titleText = '';
1404                         }
1405                         throw new MWException( "Cannot insert revision$titleText: page ID must be nonzero" );
1406                 }
1407
1408                 $this->checkContentModel();
1409
1410                 $data = $this->mText;
1411                 $flags = self::compressRevisionText( $data );
1412
1413                 # Write to external storage if required
1414                 if ( $wgDefaultExternalStore ) {
1415                         // Store and get the URL
1416                         $data = ExternalStore::insertToDefault( $data );
1417                         if ( !$data ) {
1418                                 throw new MWException( "Unable to store text to external storage" );
1419                         }
1420                         if ( $flags ) {
1421                                 $flags .= ',';
1422                         }
1423                         $flags .= 'external';
1424                 }
1425
1426                 # Record the text (or external storage URL) to the text table
1427                 if ( $this->mTextId === null ) {
1428                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1429                         $dbw->insert( 'text',
1430                                 [
1431                                         'old_id' => $old_id,
1432                                         'old_text' => $data,
1433                                         'old_flags' => $flags,
1434                                 ], __METHOD__
1435                         );
1436                         $this->mTextId = $dbw->insertId();
1437                 }
1438
1439                 if ( $this->mComment === null ) {
1440                         $this->mComment = "";
1441                 }
1442
1443                 # Record the edit in revisions
1444                 $rev_id = $this->mId !== null
1445                         ? $this->mId
1446                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1447                 $row = [
1448                         'rev_id'         => $rev_id,
1449                         'rev_page'       => $this->mPage,
1450                         'rev_text_id'    => $this->mTextId,
1451                         'rev_comment'    => $this->mComment,
1452                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1453                         'rev_user'       => $this->mUser,
1454                         'rev_user_text'  => $this->mUserText,
1455                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1456                         'rev_deleted'    => $this->mDeleted,
1457                         'rev_len'        => $this->mSize,
1458                         'rev_parent_id'  => $this->mParentId === null
1459                                 ? $this->getPreviousRevisionId( $dbw )
1460                                 : $this->mParentId,
1461                         'rev_sha1'       => $this->mSha1 === null
1462                                 ? Revision::base36Sha1( $this->mText )
1463                                 : $this->mSha1,
1464                 ];
1465
1466                 if ( $wgContentHandlerUseDB ) {
1467                         // NOTE: Store null for the default model and format, to save space.
1468                         // XXX: Makes the DB sensitive to changed defaults.
1469                         // Make this behavior optional? Only in miser mode?
1470
1471                         $model = $this->getContentModel();
1472                         $format = $this->getContentFormat();
1473
1474                         $title = $this->getTitle();
1475
1476                         if ( $title === null ) {
1477                                 throw new MWException( "Insufficient information to determine the title of the "
1478                                         . "revision's page!" );
1479                         }
1480
1481                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1482                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1483
1484                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1485                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1486                 }
1487
1488                 $dbw->insert( 'revision', $row, __METHOD__ );
1489
1490                 $this->mId = $rev_id !== null ? $rev_id : $dbw->insertId();
1491
1492                 // Assertion to try to catch T92046
1493                 if ( (int)$this->mId === 0 ) {
1494                         throw new UnexpectedValueException(
1495                                 'After insert, Revision mId is ' . var_export( $this->mId, 1 ) . ': ' .
1496                                         var_export( $row, 1 )
1497                         );
1498                 }
1499
1500                 Hooks::run( 'RevisionInsertComplete', [ &$this, $data, $flags ] );
1501
1502                 return $this->mId;
1503         }
1504
1505         protected function checkContentModel() {
1506                 global $wgContentHandlerUseDB;
1507
1508                 // Note: may return null for revisions that have not yet been inserted
1509                 $title = $this->getTitle();
1510
1511                 $model = $this->getContentModel();
1512                 $format = $this->getContentFormat();
1513                 $handler = $this->getContentHandler();
1514
1515                 if ( !$handler->isSupportedFormat( $format ) ) {
1516                         $t = $title->getPrefixedDBkey();
1517
1518                         throw new MWException( "Can't use format $format with content model $model on $t" );
1519                 }
1520
1521                 if ( !$wgContentHandlerUseDB && $title ) {
1522                         // if $wgContentHandlerUseDB is not set,
1523                         // all revisions must use the default content model and format.
1524
1525                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1526                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1527                         $defaultFormat = $defaultHandler->getDefaultFormat();
1528
1529                         if ( $this->getContentModel() != $defaultModel ) {
1530                                 $t = $title->getPrefixedDBkey();
1531
1532                                 throw new MWException( "Can't save non-default content model with "
1533                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1534                                         . "default for $t is $defaultModel" );
1535                         }
1536
1537                         if ( $this->getContentFormat() != $defaultFormat ) {
1538                                 $t = $title->getPrefixedDBkey();
1539
1540                                 throw new MWException( "Can't use non-default content format with "
1541                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1542                                         . "default for $t is $defaultFormat" );
1543                         }
1544                 }
1545
1546                 $content = $this->getContent( Revision::RAW );
1547                 $prefixedDBkey = $title->getPrefixedDBkey();
1548                 $revId = $this->mId;
1549
1550                 if ( !$content ) {
1551                         throw new MWException(
1552                                 "Content of revision $revId ($prefixedDBkey) could not be loaded for validation!"
1553                         );
1554                 }
1555                 if ( !$content->isValid() ) {
1556                         throw new MWException(
1557                                 "Content of revision $revId ($prefixedDBkey) is not valid! Content model is $model"
1558                         );
1559                 }
1560         }
1561
1562         /**
1563          * Get the base 36 SHA-1 value for a string of text
1564          * @param string $text
1565          * @return string
1566          */
1567         public static function base36Sha1( $text ) {
1568                 return Wikimedia\base_convert( sha1( $text ), 16, 36, 31 );
1569         }
1570
1571         /**
1572          * Lazy-load the revision's text.
1573          * Currently hardcoded to the 'text' table storage engine.
1574          *
1575          * @return string|bool The revision's text, or false on failure
1576          */
1577         private function loadText() {
1578                 // Caching may be beneficial for massive use of external storage
1579                 global $wgRevisionCacheExpiry;
1580                 static $processCache = null;
1581
1582                 if ( !$wgRevisionCacheExpiry ) {
1583                         return $this->fetchText();
1584                 }
1585
1586                 if ( !$processCache ) {
1587                         $processCache = new MapCacheLRU( 10 );
1588                 }
1589
1590                 $cache = ObjectCache::getMainWANInstance();
1591                 $key = $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() );
1592
1593                 // No negative caching; negative hits on text rows may be due to corrupted replica DBs
1594                 return $processCache->getWithSetCallback( $key, function () use ( $cache, $key ) {
1595                         global $wgRevisionCacheExpiry;
1596
1597                         return $cache->getWithSetCallback(
1598                                 $key,
1599                                 $wgRevisionCacheExpiry,
1600                                 function () {
1601                                         return $this->fetchText();
1602                                 }
1603                         );
1604                 } );
1605         }
1606
1607         private function fetchText() {
1608                 $textId = $this->getTextId();
1609
1610                 // If we kept data for lazy extraction, use it now...
1611                 if ( $this->mTextRow !== null ) {
1612                         $row = $this->mTextRow;
1613                         $this->mTextRow = null;
1614                 } else {
1615                         $row = null;
1616                 }
1617
1618                 if ( !$row ) {
1619                         // Text data is immutable; check replica DBs first.
1620                         $dbr = wfGetDB( DB_REPLICA );
1621                         $row = $dbr->selectRow( 'text',
1622                                 [ 'old_text', 'old_flags' ],
1623                                 [ 'old_id' => $textId ],
1624                                 __METHOD__ );
1625                 }
1626
1627                 // Fallback to the master in case of replica DB lag. Also use FOR UPDATE if it was
1628                 // used to fetch this revision to avoid missing the row due to REPEATABLE-READ.
1629                 $forUpdate = ( $this->mQueryFlags & self::READ_LOCKING == self::READ_LOCKING );
1630                 if ( !$row && ( $forUpdate || wfGetLB()->getServerCount() > 1 ) ) {
1631                         $dbw = wfGetDB( DB_MASTER );
1632                         $row = $dbw->selectRow( 'text',
1633                                 [ 'old_text', 'old_flags' ],
1634                                 [ 'old_id' => $textId ],
1635                                 __METHOD__,
1636                                 $forUpdate ? [ 'FOR UPDATE' ] : [] );
1637                 }
1638
1639                 if ( !$row ) {
1640                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1641                 }
1642
1643                 $text = self::getRevisionText( $row );
1644                 if ( $row && $text === false ) {
1645                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1646                 }
1647
1648                 return is_string( $text ) ? $text : false;
1649         }
1650
1651         /**
1652          * Create a new null-revision for insertion into a page's
1653          * history. This will not re-save the text, but simply refer
1654          * to the text from the previous version.
1655          *
1656          * Such revisions can for instance identify page rename
1657          * operations and other such meta-modifications.
1658          *
1659          * @param IDatabase $dbw
1660          * @param int $pageId ID number of the page to read from
1661          * @param string $summary Revision's summary
1662          * @param bool $minor Whether the revision should be considered as minor
1663          * @param User|null $user User object to use or null for $wgUser
1664          * @return Revision|null Revision or null on error
1665          */
1666         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1667                 global $wgContentHandlerUseDB, $wgContLang;
1668
1669                 $fields = [ 'page_latest', 'page_namespace', 'page_title',
1670                                                 'rev_text_id', 'rev_len', 'rev_sha1' ];
1671
1672                 if ( $wgContentHandlerUseDB ) {
1673                         $fields[] = 'rev_content_model';
1674                         $fields[] = 'rev_content_format';
1675                 }
1676
1677                 $current = $dbw->selectRow(
1678                         [ 'page', 'revision' ],
1679                         $fields,
1680                         [
1681                                 'page_id' => $pageId,
1682                                 'page_latest=rev_id',
1683                         ],
1684                         __METHOD__,
1685                         [ 'FOR UPDATE' ] // T51581
1686                 );
1687
1688                 if ( $current ) {
1689                         if ( !$user ) {
1690                                 global $wgUser;
1691                                 $user = $wgUser;
1692                         }
1693
1694                         // Truncate for whole multibyte characters
1695                         $summary = $wgContLang->truncate( $summary, 255 );
1696
1697                         $row = [
1698                                 'page'       => $pageId,
1699                                 'user_text'  => $user->getName(),
1700                                 'user'       => $user->getId(),
1701                                 'comment'    => $summary,
1702                                 'minor_edit' => $minor,
1703                                 'text_id'    => $current->rev_text_id,
1704                                 'parent_id'  => $current->page_latest,
1705                                 'len'        => $current->rev_len,
1706                                 'sha1'       => $current->rev_sha1
1707                         ];
1708
1709                         if ( $wgContentHandlerUseDB ) {
1710                                 $row['content_model'] = $current->rev_content_model;
1711                                 $row['content_format'] = $current->rev_content_format;
1712                         }
1713
1714                         $row['title'] = Title::makeTitle( $current->page_namespace, $current->page_title );
1715
1716                         $revision = new Revision( $row );
1717                 } else {
1718                         $revision = null;
1719                 }
1720
1721                 return $revision;
1722         }
1723
1724         /**
1725          * Determine if the current user is allowed to view a particular
1726          * field of this revision, if it's marked as deleted.
1727          *
1728          * @param int $field One of self::DELETED_TEXT,
1729          *                              self::DELETED_COMMENT,
1730          *                              self::DELETED_USER
1731          * @param User|null $user User object to check, or null to use $wgUser
1732          * @return bool
1733          */
1734         public function userCan( $field, User $user = null ) {
1735                 return self::userCanBitfield( $this->getVisibility(), $field, $user );
1736         }
1737
1738         /**
1739          * Determine if the current user is allowed to view a particular
1740          * field of this revision, if it's marked as deleted. This is used
1741          * by various classes to avoid duplication.
1742          *
1743          * @param int $bitfield Current field
1744          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1745          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1746          *                               self::DELETED_USER = File::DELETED_USER
1747          * @param User|null $user User object to check, or null to use $wgUser
1748          * @param Title|null $title A Title object to check for per-page restrictions on,
1749          *                          instead of just plain userrights
1750          * @return bool
1751          */
1752         public static function userCanBitfield( $bitfield, $field, User $user = null,
1753                 Title $title = null
1754         ) {
1755                 if ( $bitfield & $field ) { // aspect is deleted
1756                         if ( $user === null ) {
1757                                 global $wgUser;
1758                                 $user = $wgUser;
1759                         }
1760                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1761                                 $permissions = [ 'suppressrevision', 'viewsuppressed' ];
1762                         } elseif ( $field & self::DELETED_TEXT ) {
1763                                 $permissions = [ 'deletedtext' ];
1764                         } else {
1765                                 $permissions = [ 'deletedhistory' ];
1766                         }
1767                         $permissionlist = implode( ', ', $permissions );
1768                         if ( $title === null ) {
1769                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1770                                 return call_user_func_array( [ $user, 'isAllowedAny' ], $permissions );
1771                         } else {
1772                                 $text = $title->getPrefixedText();
1773                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1774                                 foreach ( $permissions as $perm ) {
1775                                         if ( $title->userCan( $perm, $user ) ) {
1776                                                 return true;
1777                                         }
1778                                 }
1779                                 return false;
1780                         }
1781                 } else {
1782                         return true;
1783                 }
1784         }
1785
1786         /**
1787          * Get rev_timestamp from rev_id, without loading the rest of the row
1788          *
1789          * @param Title $title
1790          * @param int $id
1791          * @return string|bool False if not found
1792          */
1793         static function getTimestampFromId( $title, $id, $flags = 0 ) {
1794                 $db = ( $flags & self::READ_LATEST )
1795                         ? wfGetDB( DB_MASTER )
1796                         : wfGetDB( DB_REPLICA );
1797                 // Casting fix for databases that can't take '' for rev_id
1798                 if ( $id == '' ) {
1799                         $id = 0;
1800                 }
1801                 $conds = [ 'rev_id' => $id ];
1802                 $conds['rev_page'] = $title->getArticleID();
1803                 $timestamp = $db->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1804
1805                 return ( $timestamp !== false ) ? wfTimestamp( TS_MW, $timestamp ) : false;
1806         }
1807
1808         /**
1809          * Get count of revisions per page...not very efficient
1810          *
1811          * @param IDatabase $db
1812          * @param int $id Page id
1813          * @return int
1814          */
1815         static function countByPageId( $db, $id ) {
1816                 $row = $db->selectRow( 'revision', [ 'revCount' => 'COUNT(*)' ],
1817                         [ 'rev_page' => $id ], __METHOD__ );
1818                 if ( $row ) {
1819                         return $row->revCount;
1820                 }
1821                 return 0;
1822         }
1823
1824         /**
1825          * Get count of revisions per page...not very efficient
1826          *
1827          * @param IDatabase $db
1828          * @param Title $title
1829          * @return int
1830          */
1831         static function countByTitle( $db, $title ) {
1832                 $id = $title->getArticleID();
1833                 if ( $id ) {
1834                         return self::countByPageId( $db, $id );
1835                 }
1836                 return 0;
1837         }
1838
1839         /**
1840          * Check if no edits were made by other users since
1841          * the time a user started editing the page. Limit to
1842          * 50 revisions for the sake of performance.
1843          *
1844          * @since 1.20
1845          * @deprecated since 1.24
1846          *
1847          * @param IDatabase|int $db The Database to perform the check on. May be given as a
1848          *        Database object or a database identifier usable with wfGetDB.
1849          * @param int $pageId The ID of the page in question
1850          * @param int $userId The ID of the user in question
1851          * @param string $since Look at edits since this time
1852          *
1853          * @return bool True if the given user was the only one to edit since the given timestamp
1854          */
1855         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1856                 if ( !$userId ) {
1857                         return false;
1858                 }
1859
1860                 if ( is_int( $db ) ) {
1861                         $db = wfGetDB( $db );
1862                 }
1863
1864                 $res = $db->select( 'revision',
1865                         'rev_user',
1866                         [
1867                                 'rev_page' => $pageId,
1868                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1869                         ],
1870                         __METHOD__,
1871                         [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ] );
1872                 foreach ( $res as $row ) {
1873                         if ( $row->rev_user != $userId ) {
1874                                 return false;
1875                         }
1876                 }
1877                 return true;
1878         }
1879
1880         /**
1881          * Load a revision based on a known page ID and current revision ID from the DB
1882          *
1883          * This method allows for the use of caching, though accessing anything that normally
1884          * requires permission checks (aside from the text) will trigger a small DB lookup.
1885          * The title will also be lazy loaded, though setTitle() can be used to preload it.
1886          *
1887          * @param IDatabase $db
1888          * @param int $pageId Page ID
1889          * @param int $revId Known current revision of this page
1890          * @return Revision|bool Returns false if missing
1891          * @since 1.28
1892          */
1893         public static function newKnownCurrent( IDatabase $db, $pageId, $revId ) {
1894                 $cache = ObjectCache::getMainWANInstance();
1895                 return $cache->getWithSetCallback(
1896                         // Page/rev IDs passed in from DB to reflect history merges
1897                         $cache->makeGlobalKey( 'revision', $db->getWikiID(), $pageId, $revId ),
1898                         $cache::TTL_WEEK,
1899                         function ( $curValue, &$ttl, array &$setOpts ) use ( $db, $pageId, $revId ) {
1900                                 $setOpts += Database::getCacheSetOptions( $db );
1901
1902                                 $rev = Revision::loadFromPageId( $db, $pageId, $revId );
1903                                 // Reflect revision deletion and user renames
1904                                 if ( $rev ) {
1905                                         $rev->mTitle = null; // mutable; lazy-load
1906                                         $rev->mRefreshMutableFields = true;
1907                                 }
1908
1909                                 return $rev ?: false; // don't cache negatives
1910                         }
1911                 );
1912         }
1913
1914         /**
1915          * For cached revisions, make sure the user name and rev_deleted is up-to-date
1916          */
1917         private function loadMutableFields() {
1918                 if ( !$this->mRefreshMutableFields ) {
1919                         return; // not needed
1920                 }
1921
1922                 $this->mRefreshMutableFields = false;
1923                 $dbr = wfGetLB( $this->mWiki )->getConnectionRef( DB_REPLICA, [], $this->mWiki );
1924                 $row = $dbr->selectRow(
1925                         [ 'revision', 'user' ],
1926                         [ 'rev_deleted', 'user_name' ],
1927                         [ 'rev_id' => $this->mId, 'user_id = rev_user' ],
1928                         __METHOD__
1929                 );
1930                 if ( $row ) { // update values
1931                         $this->mDeleted = (int)$row->rev_deleted;
1932                         $this->mUserText = $row->user_name;
1933                 }
1934         }
1935 }