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