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 $mTextRow;
  45
  46         /**
  47          * @var null|Title
  48          */
  49         protected $mTitle;
  50         protected $mCurrent;
  51         protected $mContentModel;
  52         protected $mContentFormat;
  53
  54         /**
  55          * @var Content|null|bool
  56          */
  57         protected $mContent;
  58
  59         /**
  60          * @var null|ContentHandler
  61          */
  62         protected $mContentHandler;
  63
  64         /**
  65          * @var int
  66          */
  67         protected $mQueryFlags = 0;
  68
  69         // Revision deletion constants
  70         const DELETED_TEXT = 1;
  71         const DELETED_COMMENT = 2;
  72         const DELETED_USER = 4;
  73         const DELETED_RESTRICTED = 8;
  74         const SUPPRESSED_USER = 12; // convenience
  75
  76         // Audience options for accessors
  77         const FOR_PUBLIC = 1;
  78         const FOR_THIS_USER = 2;
  79         const RAW = 3;
  80
  81         /**
  82          * Load a page revision from a given revision ID number.
  83          * Returns null if no such revision can be found.
  84          *
  85          * $flags include:
  86          *      Revision::READ_LATEST  : Select the data from the master
  87          *      Revision::READ_LOCKING : Select & lock the data from the master
  88          *
  89          * @param $id Integer
  90          * @param $flags Integer (optional)
  91          * @return Revision or null
  92          */
  93         public static function newFromId( $id, $flags = 0 ) {
  94                 return self::newFromConds( array( 'rev_id' => intval( $id ) ), $flags );
  95         }
  96
  97         /**
  98          * Load either the current, or a specified, revision
  99          * that's attached to a given title. If not attached
 100          * to that title, will return null.
 101          *
 102          * $flags include:
 103          *      Revision::READ_LATEST  : Select the data from the master
 104          *      Revision::READ_LOCKING : Select & lock the data from the master
 105          *
 106          * @param $title Title
 107          * @param $id Integer (optional)
 108          * @param $flags Integer Bitfield (optional)
 109          * @return Revision or null
 110          */
 111         public static function newFromTitle( $title, $id = 0, $flags = 0 ) {
 112                 $conds = array(
 113                         'page_namespace' => $title->getNamespace(),
 114                         'page_title' => $title->getDBkey()
 115                 );
 116                 if ( $id ) {
 117                         // Use the specified ID
 118                         $conds['rev_id'] = $id;
 119                         return self::newFromConds( $conds, (int)$flags );
 120                 } else {
 121                         // Use a join to get the latest revision
 122                         $conds[] = 'rev_id=page_latest';
 123                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 124                         return self::loadFromConds( $db, $conds, $flags );
 125                 }
 126         }
 127
 128         /**
 129          * Load either the current, or a specified, revision
 130          * that's attached to a given page ID.
 131          * Returns null if no such revision can be found.
 132          *
 133          * $flags include:
 134          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 135          *      Revision::READ_LOCKING : Select & lock the data from the master
 136          *
 137          * @param $revId Integer
 138          * @param $pageId Integer (optional)
 139          * @param $flags Integer Bitfield (optional)
 140          * @return Revision or null
 141          */
 142         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 143                 $conds = array( 'page_id' => $pageId );
 144                 if ( $revId ) {
 145                         $conds['rev_id'] = $revId;
 146                 } else {
 147                         // Use a join to get the latest revision
 148                         $conds[] = 'rev_id = page_latest';
 149                 }
 150                 return self::newFromConds( $conds, (int)$flags );
 151         }
 152
 153         /**
 154          * Make a fake revision object from an archive table row. This is queried
 155          * for permissions or even inserted (as in Special:Undelete)
 156          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 157          *
 158          * @param $row
 159          * @param $overrides array
 160          *
 161          * @throws MWException
 162          * @return Revision
 163          */
 164         public static function newFromArchiveRow( $row, $overrides = array() ) {
 165                 global $wgContentHandlerUseDB;
 166
 167                 $attribs = $overrides + array(
 168                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 169                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 170                         'comment'    => $row->ar_comment,
 171                         'user'       => $row->ar_user,
 172                         'user_text'  => $row->ar_user_text,
 173                         'timestamp'  => $row->ar_timestamp,
 174                         'minor_edit' => $row->ar_minor_edit,
 175                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 176                         'deleted'    => $row->ar_deleted,
 177                         'len'        => $row->ar_len,
 178                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 179                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 180                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 181                 );
 182
 183                 if ( !$wgContentHandlerUseDB ) {
 184                         unset( $attribs['content_model'] );
 185                         unset( $attribs['content_format'] );
 186                 }
 187
 188                 if ( !isset( $attribs['title'] )
 189                         && isset( $row->ar_namespace )
 190                         && isset( $row->ar_title ) ) {
 191
 192                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 193                 }
 194
 195                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 196                         // Pre-1.5 ar_text row
 197                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 198                         if ( $attribs['text'] === false ) {
 199                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 200                         }
 201                 }
 202                 return new self( $attribs );
 203         }
 204
 205         /**
 206          * @since 1.19
 207          *
 208          * @param $row
 209          * @return Revision
 210          */
 211         public static function newFromRow( $row ) {
 212                 return new self( $row );
 213         }
 214
 215         /**
 216          * Load a page revision from a given revision ID number.
 217          * Returns null if no such revision can be found.
 218          *
 219          * @param $db DatabaseBase
 220          * @param $id Integer
 221          * @return Revision or null
 222          */
 223         public static function loadFromId( $db, $id ) {
 224                 return self::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 225         }
 226
 227         /**
 228          * Load either the current, or a specified, revision
 229          * that's attached to a given page. If not attached
 230          * to that page, will return null.
 231          *
 232          * @param $db DatabaseBase
 233          * @param $pageid Integer
 234          * @param $id Integer
 235          * @return Revision or null
 236          */
 237         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 238                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) );
 239                 if ( $id ) {
 240                         $conds['rev_id'] = intval( $id );
 241                 } else {
 242                         $conds[] = 'rev_id=page_latest';
 243                 }
 244                 return self::loadFromConds( $db, $conds );
 245         }
 246
 247         /**
 248          * Load either the current, or a specified, revision
 249          * that's attached to a given page. If not attached
 250          * to that page, will return null.
 251          *
 252          * @param $db DatabaseBase
 253          * @param $title Title
 254          * @param $id Integer
 255          * @return Revision or null
 256          */
 257         public static function loadFromTitle( $db, $title, $id = 0 ) {
 258                 if ( $id ) {
 259                         $matchId = intval( $id );
 260                 } else {
 261                         $matchId = 'page_latest';
 262                 }
 263                 return self::loadFromConds( $db,
 264                         array(
 265                                 "rev_id=$matchId",
 266                                 'page_namespace' => $title->getNamespace(),
 267                                 'page_title' => $title->getDBkey()
 268                         )
 269                 );
 270         }
 271
 272         /**
 273          * Load the revision for the given title with the given timestamp.
 274          * WARNING: Timestamps may in some circumstances not be unique,
 275          * so this isn't the best key to use.
 276          *
 277          * @param $db DatabaseBase
 278          * @param $title Title
 279          * @param $timestamp String
 280          * @return Revision or null
 281          */
 282         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 283                 return self::loadFromConds( $db,
 284                         array(
 285                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 286                                 'page_namespace' => $title->getNamespace(),
 287                                 'page_title' => $title->getDBkey()
 288                         )
 289                 );
 290         }
 291
 292         /**
 293          * Given a set of conditions, fetch a revision.
 294          *
 295          * @param $conditions Array
 296          * @param $flags integer (optional)
 297          * @return Revision or null
 298          */
 299         private static function newFromConds( $conditions, $flags = 0 ) {
 300                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 301                 $rev = self::loadFromConds( $db, $conditions, $flags );
 302                 if ( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 303                         if ( !( $flags & self::READ_LATEST ) ) {
 304                                 $dbw = wfGetDB( DB_MASTER );
 305                                 $rev = self::loadFromConds( $dbw, $conditions, $flags );
 306                         }
 307                 }
 308                 if ( $rev ) {
 309                         $rev->mQueryFlags = $flags;
 310                 }
 311                 return $rev;
 312         }
 313
 314         /**
 315          * Given a set of conditions, fetch a revision from
 316          * the given database connection.
 317          *
 318          * @param $db DatabaseBase
 319          * @param $conditions Array
 320          * @param $flags integer (optional)
 321          * @return Revision or null
 322          */
 323         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 324                 $res = self::fetchFromConds( $db, $conditions, $flags );
 325                 if ( $res ) {
 326                         $row = $res->fetchObject();
 327                         if ( $row ) {
 328                                 $ret = new Revision( $row );
 329                                 return $ret;
 330                         }
 331                 }
 332                 $ret = null;
 333                 return $ret;
 334         }
 335
 336         /**
 337          * Return a wrapper for a series of database rows to
 338          * fetch all of a given page's revisions in turn.
 339          * Each row can be fed to the constructor to get objects.
 340          *
 341          * @param $title Title
 342          * @return ResultWrapper
 343          */
 344         public static function fetchRevision( $title ) {
 345                 return self::fetchFromConds(
 346                         wfGetDB( DB_SLAVE ),
 347                         array(
 348                                 'rev_id=page_latest',
 349                                 'page_namespace' => $title->getNamespace(),
 350                                 'page_title' => $title->getDBkey()
 351                         )
 352                 );
 353         }
 354
 355         /**
 356          * Given a set of conditions, return a ResultWrapper
 357          * which will return matching database rows with the
 358          * fields necessary to build Revision objects.
 359          *
 360          * @param $db DatabaseBase
 361          * @param $conditions Array
 362          * @param $flags integer (optional)
 363          * @return ResultWrapper
 364          */
 365         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 366                 $fields = array_merge(
 367                         self::selectFields(),
 368                         self::selectPageFields(),
 369                         self::selectUserFields()
 370                 );
 371                 $options = array( 'LIMIT' => 1 );
 372                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 373                         $options[] = 'FOR UPDATE';
 374                 }
 375                 return $db->select(
 376                         array( 'revision', 'page', 'user' ),
 377                         $fields,
 378                         $conditions,
 379                         __METHOD__,
 380                         $options,
 381                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 382                 );
 383         }
 384
 385         /**
 386          * Return the value of a select() JOIN conds array for the user table.
 387          * This will get user table rows for logged-in users.
 388          * @since 1.19
 389          * @return Array
 390          */
 391         public static function userJoinCond() {
 392                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 393         }
 394
 395         /**
 396          * Return the value of a select() page conds array for the page table.
 397          * This will assure that the revision(s) are not orphaned from live pages.
 398          * @since 1.19
 399          * @return Array
 400          */
 401         public static function pageJoinCond() {
 402                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 403         }
 404
 405         /**
 406          * Return the list of revision fields that should be selected to create
 407          * a new revision.
 408          * @return array
 409          */
 410         public static function selectFields() {
 411                 global $wgContentHandlerUseDB;
 412
 413                 $fields = array(
 414                         'rev_id',
 415                         'rev_page',
 416                         'rev_text_id',
 417                         'rev_timestamp',
 418                         'rev_comment',
 419                         'rev_user_text',
 420                         'rev_user',
 421                         'rev_minor_edit',
 422                         'rev_deleted',
 423                         'rev_len',
 424                         'rev_parent_id',
 425                         'rev_sha1',
 426                 );
 427
 428                 if ( $wgContentHandlerUseDB ) {
 429                         $fields[] = 'rev_content_format';
 430                         $fields[] = 'rev_content_model';
 431                 }
 432
 433                 return $fields;
 434         }
 435
 436         /**
 437          * Return the list of revision fields that should be selected to create
 438          * a new revision from an archive row.
 439          * @return array
 440          */
 441         public static function selectArchiveFields() {
 442                 global $wgContentHandlerUseDB;
 443                 $fields = array(
 444                         'ar_id',
 445                         'ar_page_id',
 446                         'ar_rev_id',
 447                         'ar_text_id',
 448                         'ar_timestamp',
 449                         'ar_comment',
 450                         'ar_user_text',
 451                         'ar_user',
 452                         'ar_minor_edit',
 453                         'ar_deleted',
 454                         'ar_len',
 455                         'ar_parent_id',
 456                         'ar_sha1',
 457                 );
 458
 459                 if ( $wgContentHandlerUseDB ) {
 460                         $fields[] = 'ar_content_format';
 461                         $fields[] = 'ar_content_model';
 462                 }
 463                 return $fields;
 464         }
 465
 466         /**
 467          * Return the list of text fields that should be selected to read the
 468          * revision text
 469          * @return array
 470          */
 471         public static function selectTextFields() {
 472                 return array(
 473                         'old_text',
 474                         'old_flags'
 475                 );
 476         }
 477
 478         /**
 479          * Return the list of page fields that should be selected from page table
 480          * @return array
 481          */
 482         public static function selectPageFields() {
 483                 return array(
 484                         'page_namespace',
 485                         'page_title',
 486                         'page_id',
 487                         'page_latest',
 488                         'page_is_redirect',
 489                         'page_len',
 490                 );
 491         }
 492
 493         /**
 494          * Return the list of user fields that should be selected from user table
 495          * @return array
 496          */
 497         public static function selectUserFields() {
 498                 return array( 'user_name' );
 499         }
 500
 501         /**
 502          * Do a batched query to get the parent revision lengths
 503          * @param $db DatabaseBase
 504          * @param $revIds Array
 505          * @return array
 506          */
 507         public static function getParentLengths( $db, array $revIds ) {
 508                 $revLens = array();
 509                 if ( !$revIds ) {
 510                         return $revLens; // empty
 511                 }
 512                 wfProfileIn( __METHOD__ );
 513                 $res = $db->select( 'revision',
 514                         array( 'rev_id', 'rev_len' ),
 515                         array( 'rev_id' => $revIds ),
 516                         __METHOD__ );
 517                 foreach ( $res as $row ) {
 518                         $revLens[$row->rev_id] = $row->rev_len;
 519                 }
 520                 wfProfileOut( __METHOD__ );
 521                 return $revLens;
 522         }
 523
 524         /**
 525          * Constructor
 526          *
 527          * @param $row Mixed: either a database row or an array
 528          * @throws MWException
 529          * @access private
 530          */
 531         function __construct( $row ) {
 532                 if ( is_object( $row ) ) {
 533                         $this->mId = intval( $row->rev_id );
 534                         $this->mPage = intval( $row->rev_page );
 535                         $this->mTextId = intval( $row->rev_text_id );
 536                         $this->mComment = $row->rev_comment;
 537                         $this->mUser = intval( $row->rev_user );
 538                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 539                         $this->mTimestamp = $row->rev_timestamp;
 540                         $this->mDeleted = intval( $row->rev_deleted );
 541
 542                         if ( !isset( $row->rev_parent_id ) ) {
 543                                 $this->mParentId = null;
 544                         } else {
 545                                 $this->mParentId = intval( $row->rev_parent_id );
 546                         }
 547
 548                         if ( !isset( $row->rev_len ) ) {
 549                                 $this->mSize = null;
 550                         } else {
 551                                 $this->mSize = intval( $row->rev_len );
 552                         }
 553
 554                         if ( !isset( $row->rev_sha1 ) ) {
 555                                 $this->mSha1 = null;
 556                         } else {
 557                                 $this->mSha1 = $row->rev_sha1;
 558                         }
 559
 560                         if ( isset( $row->page_latest ) ) {
 561                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 562                                 $this->mTitle = Title::newFromRow( $row );
 563                         } else {
 564                                 $this->mCurrent = false;
 565                                 $this->mTitle = null;
 566                         }
 567
 568                         if ( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 569                                 $this->mContentModel = null; # determine on demand if needed
 570                         } else {
 571                                 $this->mContentModel = strval( $row->rev_content_model );
 572                         }
 573
 574                         if ( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 575                                 $this->mContentFormat = null; # determine on demand if needed
 576                         } else {
 577                                 $this->mContentFormat = strval( $row->rev_content_format );
 578                         }
 579
 580                         // Lazy extraction...
 581                         $this->mText = null;
 582                         if ( isset( $row->old_text ) ) {
 583                                 $this->mTextRow = $row;
 584                         } else {
 585                                 // 'text' table row entry will be lazy-loaded
 586                                 $this->mTextRow = null;
 587                         }
 588
 589                         // Use user_name for users and rev_user_text for IPs...
 590                         $this->mUserText = null; // lazy load if left null
 591                         if ( $this->mUser == 0 ) {
 592                                 $this->mUserText = $row->rev_user_text; // IP user
 593                         } elseif ( isset( $row->user_name ) ) {
 594                                 $this->mUserText = $row->user_name; // logged-in user
 595                         }
 596                         $this->mOrigUserText = $row->rev_user_text;
 597                 } elseif ( is_array( $row ) ) {
 598                         // Build a new revision to be saved...
 599                         global $wgUser; // ugh
 600
 601                         # if we have a content object, use it to set the model and type
 602                         if ( !empty( $row['content'] ) ) {
 603                                 // @todo when is that set? test with external store setup! check out insertOn() [dk]
 604                                 if ( !empty( $row['text_id'] ) ) {
 605                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 606                                                 "can't serialize content object" );
 607                                 }
 608
 609                                 $row['content_model'] = $row['content']->getModel();
 610                                 # note: mContentFormat is initializes later accordingly
 611                                 # note: content is serialized later in this method!
 612                                 # also set text to null?
 613                         }
 614
 615                         $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 616                         $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 617                         $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 618                         $this->mUserText = isset( $row['user_text'] )
 619                                 ? strval( $row['user_text'] ) : $wgUser->getName();
 620                         $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 621                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 622                         $this->mTimestamp = isset( $row['timestamp'] )
 623                                 ? strval( $row['timestamp'] ) : wfTimestampNow();
 624                         $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 625                         $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 626                         $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 627                         $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 628
 629                         $this->mContentModel = isset( $row['content_model'] )
 630                                 ? strval( $row['content_model'] ) : null;
 631                         $this->mContentFormat = isset( $row['content_format'] )
 632                                 ? strval( $row['content_format'] ) : null;
 633
 634                         // Enforce spacing trimming on supplied text
 635                         $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 636                         $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 637                         $this->mTextRow = null;
 638
 639                         $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 640
 641                         // if we have a Content object, override mText and mContentModel
 642                         if ( !empty( $row['content'] ) ) {
 643                                 if ( !( $row['content'] instanceof Content ) ) {
 644                                         throw new MWException( '`content` field must contain a Content object.' );
 645                                 }
 646
 647                                 $handler = $this->getContentHandler();
 648                                 $this->mContent = $row['content'];
 649
 650                                 $this->mContentModel = $this->mContent->getModel();
 651                                 $this->mContentHandler = null;
 652
 653                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 654                         } elseif ( !is_null( $this->mText ) ) {
 655                                 $handler = $this->getContentHandler();
 656                                 $this->mContent = $handler->unserializeContent( $this->mText );
 657                         }
 658
 659                         // If we have a Title object, make sure it is consistent with mPage.
 660                         if ( $this->mTitle && $this->mTitle->exists() ) {
 661                                 if ( $this->mPage === null ) {
 662                                         // if the page ID wasn't known, set it now
 663                                         $this->mPage = $this->mTitle->getArticleID();
 664                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 665                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 666                                         // but it seems worth mentioning it in the log.
 667                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 668                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 669                                 }
 670                         }
 671
 672                         $this->mCurrent = false;
 673
 674                         // If we still have no length, see it we have the text to figure it out
 675                         if ( !$this->mSize ) {
 676                                 if ( !is_null( $this->mContent ) ) {
 677                                         $this->mSize = $this->mContent->getSize();
 678                                 } else {
 679                                         #NOTE: this should never happen if we have either text or content object!
 680                                         $this->mSize = null;
 681                                 }
 682                         }
 683
 684                         // Same for sha1
 685                         if ( $this->mSha1 === null ) {
 686                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 687                         }
 688
 689                         // force lazy init
 690                         $this->getContentModel();
 691                         $this->getContentFormat();
 692                 } else {
 693                         throw new MWException( 'Revision constructor passed invalid row format.' );
 694                 }
 695                 $this->mUnpatrolled = null;
 696         }
 697
 698         /**
 699          * Get revision ID
 700          *
 701          * @return Integer|null
 702          */
 703         public function getId() {
 704                 return $this->mId;
 705         }
 706
 707         /**
 708          * Set the revision ID
 709          *
 710          * @since 1.19
 711          * @param $id Integer
 712          */
 713         public function setId( $id ) {
 714                 $this->mId = $id;
 715         }
 716
 717         /**
 718          * Get text row ID
 719          *
 720          * @return Integer|null
 721          */
 722         public function getTextId() {
 723                 return $this->mTextId;
 724         }
 725
 726         /**
 727          * Get parent revision ID (the original previous page revision)
 728          *
 729          * @return Integer|null
 730          */
 731         public function getParentId() {
 732                 return $this->mParentId;
 733         }
 734
 735         /**
 736          * Returns the length of the text in this revision, or null if unknown.
 737          *
 738          * @return Integer|null
 739          */
 740         public function getSize() {
 741                 return $this->mSize;
 742         }
 743
 744         /**
 745          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 746          *
 747          * @return String|null
 748          */
 749         public function getSha1() {
 750                 return $this->mSha1;
 751         }
 752
 753         /**
 754          * Returns the title of the page associated with this entry or null.
 755          *
 756          * Will do a query, when title is not set and id is given.
 757          *
 758          * @return Title|null
 759          */
 760         public function getTitle() {
 761                 if ( isset( $this->mTitle ) ) {
 762                         return $this->mTitle;
 763                 }
 764                 //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 765                 if ( !is_null( $this->mId ) ) {
 766                         $dbr = wfGetDB( DB_SLAVE );
 767                         $row = $dbr->selectRow(
 768                                 array( 'page', 'revision' ),
 769                                 self::selectPageFields(),
 770                                 array( 'page_id=rev_page',
 771                                         'rev_id' => $this->mId ),
 772                                 __METHOD__ );
 773                         if ( $row ) {
 774                                 $this->mTitle = Title::newFromRow( $row );
 775                         }
 776                 }
 777
 778                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 779                         $this->mTitle = Title::newFromID( $this->mPage );
 780                 }
 781
 782                 return $this->mTitle;
 783         }
 784
 785         /**
 786          * Set the title of the revision
 787          *
 788          * @param $title Title
 789          */
 790         public function setTitle( $title ) {
 791                 $this->mTitle = $title;
 792         }
 793
 794         /**
 795          * Get the page ID
 796          *
 797          * @return Integer|null
 798          */
 799         public function getPage() {
 800                 return $this->mPage;
 801         }
 802
 803         /**
 804          * Fetch revision's user id if it's available to the specified audience.
 805          * If the specified audience does not have access to it, zero will be
 806          * returned.
 807          *
 808          * @param $audience Integer: one of:
 809          *      Revision::FOR_PUBLIC       to be displayed to all users
 810          *      Revision::FOR_THIS_USER    to be displayed to the given user
 811          *      Revision::RAW              get the ID regardless of permissions
 812          * @param $user User object to check for, only if FOR_THIS_USER is passed
 813          *              to the $audience parameter
 814          * @return Integer
 815          */
 816         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 817                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 818                         return 0;
 819                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 820                         return 0;
 821                 } else {
 822                         return $this->mUser;
 823                 }
 824         }
 825
 826         /**
 827          * Fetch revision's user id without regard for the current user's permissions
 828          *
 829          * @return String
 830          */
 831         public function getRawUser() {
 832                 return $this->mUser;
 833         }
 834
 835         /**
 836          * Fetch revision's username if it's available to the specified audience.
 837          * If the specified audience does not have access to the username, an
 838          * empty string will be returned.
 839          *
 840          * @param $audience Integer: one of:
 841          *      Revision::FOR_PUBLIC       to be displayed to all users
 842          *      Revision::FOR_THIS_USER    to be displayed to the given user
 843          *      Revision::RAW              get the text regardless of permissions
 844          * @param $user User object to check for, only if FOR_THIS_USER is passed
 845          *              to the $audience parameter
 846          * @return string
 847          */
 848         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 849                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 850                         return '';
 851                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 852                         return '';
 853                 } else {
 854                         return $this->getRawUserText();
 855                 }
 856         }
 857
 858         /**
 859          * Fetch revision's username without regard for view restrictions
 860          *
 861          * @return String
 862          */
 863         public function getRawUserText() {
 864                 if ( $this->mUserText === null ) {
 865                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 866                         if ( $this->mUserText === false ) {
 867                                 # This shouldn't happen, but it can if the wiki was recovered
 868                                 # via importing revs and there is no user table entry yet.
 869                                 $this->mUserText = $this->mOrigUserText;
 870                         }
 871                 }
 872                 return $this->mUserText;
 873         }
 874
 875         /**
 876          * Fetch revision comment if it's available to the specified audience.
 877          * If the specified audience does not have access to the comment, an
 878          * empty string will be returned.
 879          *
 880          * @param $audience Integer: one of:
 881          *      Revision::FOR_PUBLIC       to be displayed to all users
 882          *      Revision::FOR_THIS_USER    to be displayed to the given user
 883          *      Revision::RAW              get the text regardless of permissions
 884          * @param $user User object to check for, only if FOR_THIS_USER is passed
 885          *              to the $audience parameter
 886          * @return String
 887          */
 888         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 889                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 890                         return '';
 891                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 892                         return '';
 893                 } else {
 894                         return $this->mComment;
 895                 }
 896         }
 897
 898         /**
 899          * Fetch revision comment without regard for the current user's permissions
 900          *
 901          * @return String
 902          */
 903         public function getRawComment() {
 904                 return $this->mComment;
 905         }
 906
 907         /**
 908          * @return Boolean
 909          */
 910         public function isMinor() {
 911                 return (bool)$this->mMinorEdit;
 912         }
 913
 914         /**
 915          * @return integer rcid of the unpatrolled row, zero if there isn't one
 916          */
 917         public function isUnpatrolled() {
 918                 if ( $this->mUnpatrolled !== null ) {
 919                         return $this->mUnpatrolled;
 920                 }
 921                 $rc = $this->getRecentChange();
 922                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 923                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 924                 } else {
 925                         $this->mUnpatrolled = 0;
 926                 }
 927                 return $this->mUnpatrolled;
 928         }
 929
 930         /**
 931          * Get the RC object belonging to the current revision, if there's one
 932          *
 933          * @since 1.22
 934          * @return RecentChange|null
 935          */
 936         public function getRecentChange() {
 937                 $dbr = wfGetDB( DB_SLAVE );
 938                 return RecentChange::newFromConds(
 939                         array(
 940                                 'rc_user_text' => $this->getRawUserText(),
 941                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
 942                                 'rc_this_oldid' => $this->getId()
 943                         ),
 944                         __METHOD__
 945                 );
 946         }
 947
 948         /**
 949          * @param int $field one of DELETED_* bitfield constants
 950          *
 951          * @return Boolean
 952          */
 953         public function isDeleted( $field ) {
 954                 return ( $this->mDeleted & $field ) == $field;
 955         }
 956
 957         /**
 958          * Get the deletion bitfield of the revision
 959          *
 960          * @return int
 961          */
 962         public function getVisibility() {
 963                 return (int)$this->mDeleted;
 964         }
 965
 966         /**
 967          * Fetch revision text if it's available to the specified audience.
 968          * If the specified audience does not have the ability to view this
 969          * revision, an empty string will be returned.
 970          *
 971          * @param $audience Integer: one of:
 972          *      Revision::FOR_PUBLIC       to be displayed to all users
 973          *      Revision::FOR_THIS_USER    to be displayed to the given user
 974          *      Revision::RAW              get the text regardless of permissions
 975          * @param $user User object to check for, only if FOR_THIS_USER is passed
 976          *              to the $audience parameter
 977          *
 978          * @deprecated in 1.21, use getContent() instead
 979          * @todo Replace usage in core
 980          * @return String
 981          */
 982         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 983                 ContentHandler::deprecated( __METHOD__, '1.21' );
 984
 985                 $content = $this->getContent( $audience, $user );
 986                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 987         }
 988
 989         /**
 990          * Fetch revision content if it's available to the specified audience.
 991          * If the specified audience does not have the ability to view this
 992          * revision, null will be returned.
 993          *
 994          * @param $audience Integer: one of:
 995          *      Revision::FOR_PUBLIC       to be displayed to all users
 996          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 997          *      Revision::RAW              get the text regardless of permissions
 998          * @param $user User object to check for, only if FOR_THIS_USER is passed
 999          *              to the $audience parameter
1000          * @since 1.21
1001          * @return Content|null
1002          */
1003         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1004                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1005                         return null;
1006                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1007                         return null;
1008                 } else {
1009                         return $this->getContentInternal();
1010                 }
1011         }
1012
1013         /**
1014          * Alias for getText(Revision::FOR_THIS_USER)
1015          *
1016          * @deprecated since 1.17
1017          * @return String
1018          */
1019         public function revText() {
1020                 wfDeprecated( __METHOD__, '1.17' );
1021                 return $this->getText( self::FOR_THIS_USER );
1022         }
1023
1024         /**
1025          * Fetch revision text without regard for view restrictions
1026          *
1027          * @return String
1028          *
1029          * @deprecated since 1.21. Instead, use Revision::getContent( Revision::RAW )
1030          *                         or Revision::getSerializedData() as appropriate.
1031          */
1032         public function getRawText() {
1033                 ContentHandler::deprecated( __METHOD__, "1.21" );
1034                 return $this->getText( self::RAW );
1035         }
1036
1037         /**
1038          * Fetch original serialized data without regard for view restrictions
1039          *
1040          * @since 1.21
1041          * @return String
1042          */
1043         public function getSerializedData() {
1044                 if ( is_null( $this->mText ) ) {
1045                         $this->mText = $this->loadText();
1046                 }
1047
1048                 return $this->mText;
1049         }
1050
1051         /**
1052          * Gets the content object for the revision (or null on failure).
1053          *
1054          * Note that for mutable Content objects, each call to this method will return a
1055          * fresh clone.
1056          *
1057          * @since 1.21
1058          * @return Content|null the Revision's content, or null on failure.
1059          */
1060         protected function getContentInternal() {
1061                 if ( is_null( $this->mContent ) ) {
1062                         // Revision is immutable. Load on demand:
1063                         if ( is_null( $this->mText ) ) {
1064                                 $this->mText = $this->loadText();
1065                         }
1066
1067                         if ( $this->mText !== null && $this->mText !== false ) {
1068                                 // Unserialize content
1069                                 $handler = $this->getContentHandler();
1070                                 $format = $this->getContentFormat();
1071
1072                                 $this->mContent = $handler->unserializeContent( $this->mText, $format );
1073                         } else {
1074                                 $this->mContent = false; // negative caching!
1075                         }
1076                 }
1077
1078                 // NOTE: copy() will return $this for immutable content objects
1079                 return $this->mContent ? $this->mContent->copy() : null;
1080         }
1081
1082         /**
1083          * Returns the content model for this revision.
1084          *
1085          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
1086          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1087          * is used as a last resort.
1088          *
1089          * @return String the content model id associated with this revision,
1090          *     see the CONTENT_MODEL_XXX constants.
1091          **/
1092         public function getContentModel() {
1093                 if ( !$this->mContentModel ) {
1094                         $title = $this->getTitle();
1095                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
1096
1097                         assert( !empty( $this->mContentModel ) );
1098                 }
1099
1100                 return $this->mContentModel;
1101         }
1102
1103         /**
1104          * Returns the content format for this revision.
1105          *
1106          * If no content format was stored in the database, the default format for this
1107          * revision's content model is returned.
1108          *
1109          * @return String the content format id associated with this revision,
1110          *     see the CONTENT_FORMAT_XXX constants.
1111          **/
1112         public function getContentFormat() {
1113                 if ( !$this->mContentFormat ) {
1114                         $handler = $this->getContentHandler();
1115                         $this->mContentFormat = $handler->getDefaultFormat();
1116
1117                         assert( !empty( $this->mContentFormat ) );
1118                 }
1119
1120                 return $this->mContentFormat;
1121         }
1122
1123         /**
1124          * Returns the content handler appropriate for this revision's content model.
1125          *
1126          * @throws MWException
1127          * @return ContentHandler
1128          */
1129         public function getContentHandler() {
1130                 if ( !$this->mContentHandler ) {
1131                         $model = $this->getContentModel();
1132                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1133
1134                         $format = $this->getContentFormat();
1135
1136                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1137                                 throw new MWException( "Oops, the content format $format is not supported for "
1138                                         . "this content model, $model" );
1139                         }
1140                 }
1141
1142                 return $this->mContentHandler;
1143         }
1144
1145         /**
1146          * @return String
1147          */
1148         public function getTimestamp() {
1149                 return wfTimestamp( TS_MW, $this->mTimestamp );
1150         }
1151
1152         /**
1153          * @return Boolean
1154          */
1155         public function isCurrent() {
1156                 return $this->mCurrent;
1157         }
1158
1159         /**
1160          * Get previous revision for this title
1161          *
1162          * @return Revision|null
1163          */
1164         public function getPrevious() {
1165                 if ( $this->getTitle() ) {
1166                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1167                         if ( $prev ) {
1168                                 return self::newFromTitle( $this->getTitle(), $prev );
1169                         }
1170                 }
1171                 return null;
1172         }
1173
1174         /**
1175          * Get next revision for this title
1176          *
1177          * @return Revision or null
1178          */
1179         public function getNext() {
1180                 if ( $this->getTitle() ) {
1181                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1182                         if ( $next ) {
1183                                 return self::newFromTitle( $this->getTitle(), $next );
1184                         }
1185                 }
1186                 return null;
1187         }
1188
1189         /**
1190          * Get previous revision Id for this page_id
1191          * This is used to populate rev_parent_id on save
1192          *
1193          * @param $db DatabaseBase
1194          * @return Integer
1195          */
1196         private function getPreviousRevisionId( $db ) {
1197                 if ( is_null( $this->mPage ) ) {
1198                         return 0;
1199                 }
1200                 # Use page_latest if ID is not given
1201                 if ( !$this->mId ) {
1202                         $prevId = $db->selectField( 'page', 'page_latest',
1203                                 array( 'page_id' => $this->mPage ),
1204                                 __METHOD__ );
1205                 } else {
1206                         $prevId = $db->selectField( 'revision', 'rev_id',
1207                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1208                                 __METHOD__,
1209                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1210                 }
1211                 return intval( $prevId );
1212         }
1213
1214         /**
1215           * Get revision text associated with an old or archive row
1216           * $row is usually an object from wfFetchRow(), both the flags and the text
1217           * field must be included
1218           *
1219           * @param $row Object: the text data
1220           * @param string $prefix table prefix (default 'old_')
1221           * @param string|false $wiki the name of the wiki to load the revision text from
1222           *         (same as the the wiki $row was loaded from) or false to indicate the local
1223           *         wiki (this is the default). Otherwise, it must be a symbolic wiki database
1224           *         identifier as understood by the LoadBalancer class.
1225           * @return String: text the text requested or false on failure
1226           */
1227         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1228                 wfProfileIn( __METHOD__ );
1229
1230                 # Get data
1231                 $textField = $prefix . 'text';
1232                 $flagsField = $prefix . 'flags';
1233
1234                 if ( isset( $row->$flagsField ) ) {
1235                         $flags = explode( ',', $row->$flagsField );
1236                 } else {
1237                         $flags = array();
1238                 }
1239
1240                 if ( isset( $row->$textField ) ) {
1241                         $text = $row->$textField;
1242                 } else {
1243                         wfProfileOut( __METHOD__ );
1244                         return false;
1245                 }
1246
1247                 # Use external methods for external objects, text in table is URL-only then
1248                 if ( in_array( 'external', $flags ) ) {
1249                         $url = $text;
1250                         $parts = explode( '://', $url, 2 );
1251                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1252                                 wfProfileOut( __METHOD__ );
1253                                 return false;
1254                         }
1255                         $text = ExternalStore::fetchFromURL( $url, array( 'wiki' => $wiki ) );
1256                 }
1257
1258                 // If the text was fetched without an error, convert it
1259                 if ( $text !== false ) {
1260                         $text = self::decompressRevisionText( $text, $flags );
1261                 }
1262                 wfProfileOut( __METHOD__ );
1263                 return $text;
1264         }
1265
1266         /**
1267          * If $wgCompressRevisions is enabled, we will compress data.
1268          * The input string is modified in place.
1269          * Return value is the flags field: contains 'gzip' if the
1270          * data is compressed, and 'utf-8' if we're saving in UTF-8
1271          * mode.
1272          *
1273          * @param $text Mixed: reference to a text
1274          * @return String
1275          */
1276         public static function compressRevisionText( &$text ) {
1277                 global $wgCompressRevisions;
1278                 $flags = array();
1279
1280                 # Revisions not marked this way will be converted
1281                 # on load if $wgLegacyCharset is set in the future.
1282                 $flags[] = 'utf-8';
1283
1284                 if ( $wgCompressRevisions ) {
1285                         if ( function_exists( 'gzdeflate' ) ) {
1286                                 $text = gzdeflate( $text );
1287                                 $flags[] = 'gzip';
1288                         } else {
1289                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1290                         }
1291                 }
1292                 return implode( ',', $flags );
1293         }
1294
1295         /**
1296          * Re-converts revision text according to it's flags.
1297          *
1298          * @param $text Mixed: reference to a text
1299          * @param $flags array: compression flags
1300          * @return String|bool decompressed text, or false on failure
1301          */
1302         public static function decompressRevisionText( $text, $flags ) {
1303                 if ( in_array( 'gzip', $flags ) ) {
1304                         # Deal with optional compression of archived pages.
1305                         # This can be done periodically via maintenance/compressOld.php, and
1306                         # as pages are saved if $wgCompressRevisions is set.
1307                         $text = gzinflate( $text );
1308                 }
1309
1310                 if ( in_array( 'object', $flags ) ) {
1311                         # Generic compressed storage
1312                         $obj = unserialize( $text );
1313                         if ( !is_object( $obj ) ) {
1314                                 // Invalid object
1315                                 return false;
1316                         }
1317                         $text = $obj->getText();
1318                 }
1319
1320                 global $wgLegacyEncoding;
1321                 if ( $text !== false && $wgLegacyEncoding
1322                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1323                 ) {
1324                         # Old revisions kept around in a legacy encoding?
1325                         # Upconvert on demand.
1326                         # ("utf8" checked for compatibility with some broken
1327                         #  conversion scripts 2008-12-30)
1328                         global $wgContLang;
1329                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1330                 }
1331
1332                 return $text;
1333         }
1334
1335         /**
1336          * Insert a new revision into the database, returning the new revision ID
1337          * number on success and dies horribly on failure.
1338          *
1339          * @param $dbw DatabaseBase: (master connection)
1340          * @throws MWException
1341          * @return Integer
1342          */
1343         public function insertOn( $dbw ) {
1344                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1345
1346                 wfProfileIn( __METHOD__ );
1347
1348                 $this->checkContentModel();
1349
1350                 $data = $this->mText;
1351                 $flags = self::compressRevisionText( $data );
1352
1353                 # Write to external storage if required
1354                 if ( $wgDefaultExternalStore ) {
1355                         // Store and get the URL
1356                         $data = ExternalStore::insertToDefault( $data );
1357                         if ( !$data ) {
1358                                 wfProfileOut( __METHOD__ );
1359                                 throw new MWException( "Unable to store text to external storage" );
1360                         }
1361                         if ( $flags ) {
1362                                 $flags .= ',';
1363                         }
1364                         $flags .= 'external';
1365                 }
1366
1367                 # Record the text (or external storage URL) to the text table
1368                 if ( !isset( $this->mTextId ) ) {
1369                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1370                         $dbw->insert( 'text',
1371                                 array(
1372                                         'old_id' => $old_id,
1373                                         'old_text' => $data,
1374                                         'old_flags' => $flags,
1375                                 ), __METHOD__
1376                         );
1377                         $this->mTextId = $dbw->insertId();
1378                 }
1379
1380                 if ( $this->mComment === null ) {
1381                         $this->mComment = "";
1382                 }
1383
1384                 # Record the edit in revisions
1385                 $rev_id = isset( $this->mId )
1386                         ? $this->mId
1387                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1388                 $row = array(
1389                         'rev_id'         => $rev_id,
1390                         'rev_page'       => $this->mPage,
1391                         'rev_text_id'    => $this->mTextId,
1392                         'rev_comment'    => $this->mComment,
1393                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1394                         'rev_user'       => $this->mUser,
1395                         'rev_user_text'  => $this->mUserText,
1396                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1397                         'rev_deleted'    => $this->mDeleted,
1398                         'rev_len'        => $this->mSize,
1399                         'rev_parent_id'  => is_null( $this->mParentId )
1400                                 ? $this->getPreviousRevisionId( $dbw )
1401                                 : $this->mParentId,
1402                         'rev_sha1'       => is_null( $this->mSha1 )
1403                                 ? Revision::base36Sha1( $this->mText )
1404                                 : $this->mSha1,
1405                 );
1406
1407                 if ( $wgContentHandlerUseDB ) {
1408                         //NOTE: Store null for the default model and format, to save space.
1409                         //XXX: Makes the DB sensitive to changed defaults.
1410                         // Make this behavior optional? Only in miser mode?
1411
1412                         $model = $this->getContentModel();
1413                         $format = $this->getContentFormat();
1414
1415                         $title = $this->getTitle();
1416
1417                         if ( $title === null ) {
1418                                 wfProfileOut( __METHOD__ );
1419                                 throw new MWException( "Insufficient information to determine the title of the "
1420                                         . "revision's page!" );
1421                         }
1422
1423                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1424                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1425
1426                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1427                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1428                 }
1429
1430                 $dbw->insert( 'revision', $row, __METHOD__ );
1431
1432                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1433
1434                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1435
1436                 wfProfileOut( __METHOD__ );
1437                 return $this->mId;
1438         }
1439
1440         protected function checkContentModel() {
1441                 global $wgContentHandlerUseDB;
1442
1443                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1444
1445                 $model = $this->getContentModel();
1446                 $format = $this->getContentFormat();
1447                 $handler = $this->getContentHandler();
1448
1449                 if ( !$handler->isSupportedFormat( $format ) ) {
1450                         $t = $title->getPrefixedDBkey();
1451
1452                         throw new MWException( "Can't use format $format with content model $model on $t" );
1453                 }
1454
1455                 if ( !$wgContentHandlerUseDB && $title ) {
1456                         // if $wgContentHandlerUseDB is not set,
1457                         // all revisions must use the default content model and format.
1458
1459                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1460                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1461                         $defaultFormat = $defaultHandler->getDefaultFormat();
1462
1463                         if ( $this->getContentModel() != $defaultModel ) {
1464                                 $t = $title->getPrefixedDBkey();
1465
1466                                 throw new MWException( "Can't save non-default content model with "
1467                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1468                                         . "default for $t is $defaultModel" );
1469                         }
1470
1471                         if ( $this->getContentFormat() != $defaultFormat ) {
1472                                 $t = $title->getPrefixedDBkey();
1473
1474                                 throw new MWException( "Can't use non-default content format with "
1475                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1476                                         . "default for $t is $defaultFormat" );
1477                         }
1478                 }
1479
1480                 $content = $this->getContent( Revision::RAW );
1481
1482                 if ( !$content || !$content->isValid() ) {
1483                         $t = $title->getPrefixedDBkey();
1484
1485                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1486                 }
1487         }
1488
1489         /**
1490          * Get the base 36 SHA-1 value for a string of text
1491          * @param $text String
1492          * @return String
1493          */
1494         public static function base36Sha1( $text ) {
1495                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1496         }
1497
1498         /**
1499          * Lazy-load the revision's text.
1500          * Currently hardcoded to the 'text' table storage engine.
1501          *
1502          * @return String|bool the revision's text, or false on failure
1503          */
1504         protected function loadText() {
1505                 wfProfileIn( __METHOD__ );
1506
1507                 // Caching may be beneficial for massive use of external storage
1508                 global $wgRevisionCacheExpiry, $wgMemc;
1509                 $textId = $this->getTextId();
1510                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1511                 if ( $wgRevisionCacheExpiry ) {
1512                         $text = $wgMemc->get( $key );
1513                         if ( is_string( $text ) ) {
1514                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1515                                 wfProfileOut( __METHOD__ );
1516                                 return $text;
1517                         }
1518                 }
1519
1520                 // If we kept data for lazy extraction, use it now...
1521                 if ( isset( $this->mTextRow ) ) {
1522                         $row = $this->mTextRow;
1523                         $this->mTextRow = null;
1524                 } else {
1525                         $row = null;
1526                 }
1527
1528                 if ( !$row ) {
1529                         // Text data is immutable; check slaves first.
1530                         $dbr = wfGetDB( DB_SLAVE );
1531                         $row = $dbr->selectRow( 'text',
1532                                 array( 'old_text', 'old_flags' ),
1533                                 array( 'old_id' => $textId ),
1534                                 __METHOD__ );
1535                 }
1536
1537                 // Fallback to the master in case of slave lag. Also use FOR UPDATE if it was
1538                 // used to fetch this revision to avoid missing the row due to REPEATABLE-READ.
1539                 $forUpdate = ( $this->mQueryFlags & self::READ_LOCKING == self::READ_LOCKING );
1540                 if ( !$row && ( $forUpdate || wfGetLB()->getServerCount() > 1 ) ) {
1541                         $dbw = wfGetDB( DB_MASTER );
1542                         $row = $dbw->selectRow( 'text',
1543                                 array( 'old_text', 'old_flags' ),
1544                                 array( 'old_id' => $textId ),
1545                                 __METHOD__,
1546                                 $forUpdate ? array( 'FOR UPDATE' ) : array() );
1547                 }
1548
1549                 if ( !$row ) {
1550                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1551                 }
1552
1553                 $text = self::getRevisionText( $row );
1554                 if ( $row && $text === false ) {
1555                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1556                 }
1557
1558                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1559                 if ( $wgRevisionCacheExpiry && $text !== false ) {
1560                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1561                 }
1562
1563                 wfProfileOut( __METHOD__ );
1564
1565                 return $text;
1566         }
1567
1568         /**
1569          * Create a new null-revision for insertion into a page's
1570          * history. This will not re-save the text, but simply refer
1571          * to the text from the previous version.
1572          *
1573          * Such revisions can for instance identify page rename
1574          * operations and other such meta-modifications.
1575          *
1576          * @param $dbw DatabaseBase
1577          * @param $pageId Integer: ID number of the page to read from
1578          * @param string $summary revision's summary
1579          * @param $minor Boolean: whether the revision should be considered as minor
1580          * @return Revision|null on error
1581          */
1582         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1583                 global $wgContentHandlerUseDB;
1584
1585                 wfProfileIn( __METHOD__ );
1586
1587                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1588                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1589
1590                 if ( $wgContentHandlerUseDB ) {
1591                         $fields[] = 'rev_content_model';
1592                         $fields[] = 'rev_content_format';
1593                 }
1594
1595                 $current = $dbw->selectRow(
1596                         array( 'page', 'revision' ),
1597                         $fields,
1598                         array(
1599                                 'page_id' => $pageId,
1600                                 'page_latest=rev_id',
1601                                 ),
1602                         __METHOD__ );
1603
1604                 if ( $current ) {
1605                         $row = array(
1606                                 'page'       => $pageId,
1607                                 'comment'    => $summary,
1608                                 'minor_edit' => $minor,
1609                                 'text_id'    => $current->rev_text_id,
1610                                 'parent_id'  => $current->page_latest,
1611                                 'len'        => $current->rev_len,
1612                                 'sha1'       => $current->rev_sha1
1613                         );
1614
1615                         if ( $wgContentHandlerUseDB ) {
1616                                 $row['content_model'] = $current->rev_content_model;
1617                                 $row['content_format'] = $current->rev_content_format;
1618                         }
1619
1620                         $revision = new Revision( $row );
1621                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1622                 } else {
1623                         $revision = null;
1624                 }
1625
1626                 wfProfileOut( __METHOD__ );
1627                 return $revision;
1628         }
1629
1630         /**
1631          * Determine if the current user is allowed to view a particular
1632          * field of this revision, if it's marked as deleted.
1633          *
1634          * @param $field Integer:one of self::DELETED_TEXT,
1635          *                              self::DELETED_COMMENT,
1636          *                              self::DELETED_USER
1637          * @param $user User object to check, or null to use $wgUser
1638          * @return Boolean
1639          */
1640         public function userCan( $field, User $user = null ) {
1641                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1642         }
1643
1644         /**
1645          * Determine if the current user is allowed to view a particular
1646          * field of this revision, if it's marked as deleted. This is used
1647          * by various classes to avoid duplication.
1648          *
1649          * @param $bitfield Integer: current field
1650          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1651          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1652          *                               self::DELETED_USER = File::DELETED_USER
1653          * @param $user User object to check, or null to use $wgUser
1654          * @return Boolean
1655          */
1656         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1657                 if ( $bitfield & $field ) { // aspect is deleted
1658                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1659                                 $permission = 'suppressrevision';
1660                         } elseif ( $field & self::DELETED_TEXT ) {
1661                                 $permission = 'deletedtext';
1662                         } else {
1663                                 $permission = 'deletedhistory';
1664                         }
1665                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1666                         if ( $user === null ) {
1667                                 global $wgUser;
1668                                 $user = $wgUser;
1669                         }
1670                         return $user->isAllowed( $permission );
1671                 } else {
1672                         return true;
1673                 }
1674         }
1675
1676         /**
1677          * Get rev_timestamp from rev_id, without loading the rest of the row
1678          *
1679          * @param $title Title
1680          * @param $id Integer
1681          * @return String
1682          */
1683         static function getTimestampFromId( $title, $id ) {
1684                 $dbr = wfGetDB( DB_SLAVE );
1685                 // Casting fix for databases that can't take '' for rev_id
1686                 if ( $id == '' ) {
1687                         $id = 0;
1688                 }
1689                 $conds = array( 'rev_id' => $id );
1690                 $conds['rev_page'] = $title->getArticleID();
1691                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1692                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1693                         # Not in slave, try master
1694                         $dbw = wfGetDB( DB_MASTER );
1695                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1696                 }
1697                 return wfTimestamp( TS_MW, $timestamp );
1698         }
1699
1700         /**
1701          * Get count of revisions per page...not very efficient
1702          *
1703          * @param $db DatabaseBase
1704          * @param $id Integer: page id
1705          * @return Integer
1706          */
1707         static function countByPageId( $db, $id ) {
1708                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1709                         array( 'rev_page' => $id ), __METHOD__ );
1710                 if ( $row ) {
1711                         return $row->revCount;
1712                 }
1713                 return 0;
1714         }
1715
1716         /**
1717          * Get count of revisions per page...not very efficient
1718          *
1719          * @param $db DatabaseBase
1720          * @param $title Title
1721          * @return Integer
1722          */
1723         static function countByTitle( $db, $title ) {
1724                 $id = $title->getArticleID();
1725                 if ( $id ) {
1726                         return self::countByPageId( $db, $id );
1727                 }
1728                 return 0;
1729         }
1730
1731         /**
1732          * Check if no edits were made by other users since
1733          * the time a user started editing the page. Limit to
1734          * 50 revisions for the sake of performance.
1735          *
1736          * @since 1.20
1737          *
1738          * @param DatabaseBase|int $db the Database to perform the check on. May be given as a
1739          *        Database object or a database identifier usable with wfGetDB.
1740          * @param int $pageId the ID of the page in question
1741          * @param int $userId the ID of the user in question
1742          * @param string $since look at edits since this time
1743          *
1744          * @return bool True if the given user was the only one to edit since the given timestamp
1745          */
1746         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1747                 if ( !$userId ) {
1748                         return false;
1749                 }
1750
1751                 if ( is_int( $db ) ) {
1752                         $db = wfGetDB( $db );
1753                 }
1754
1755                 $res = $db->select( 'revision',
1756                         'rev_user',
1757                         array(
1758                                 'rev_page' => $pageId,
1759                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1760                         ),
1761                         __METHOD__,
1762                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1763                 foreach ( $res as $row ) {
1764                         if ( $row->rev_user != $userId ) {
1765                                 return false;
1766                         }
1767                 }
1768                 return true;
1769         }
1770 }