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']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 619                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 620                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 621                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 622                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 623                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 624                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 625                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 626
 627                         $this->mContentModel   = isset( $row['content_model']  )  ? strval( $row['content_model'] )  : null;
 628                         $this->mContentFormat  = isset( $row['content_format']  ) ? strval( $row['content_format'] ) : null;
 629
 630                         // Enforce spacing trimming on supplied text
 631                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 632                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 633                         $this->mTextRow   = null;
 634
 635                         $this->mTitle     = isset( $row['title']      ) ? $row['title'] : null;
 636
 637                         // if we have a Content object, override mText and mContentModel
 638                         if ( !empty( $row['content'] ) ) {
 639                                 if ( !( $row['content'] instanceof Content ) ) {
 640                                         throw new MWException( '`content` field must contain a Content object.' );
 641                                 }
 642
 643                                 $handler = $this->getContentHandler();
 644                                 $this->mContent = $row['content'];
 645
 646                                 $this->mContentModel = $this->mContent->getModel();
 647                                 $this->mContentHandler = null;
 648
 649                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 650                         } elseif ( !is_null( $this->mText ) ) {
 651                                 $handler = $this->getContentHandler();
 652                                 $this->mContent = $handler->unserializeContent( $this->mText );
 653                         }
 654
 655                         // If we have a Title object, make sure it is consistent with mPage.
 656                         if ( $this->mTitle && $this->mTitle->exists() ) {
 657                                 if ( $this->mPage === null ) {
 658                                         // if the page ID wasn't known, set it now
 659                                         $this->mPage = $this->mTitle->getArticleID();
 660                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 661                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 662                                         // but it seems worth mentioning it in the log.
 663                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 664                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 665                                 }
 666                         }
 667
 668                         $this->mCurrent = false;
 669
 670                         // If we still have no length, see it we have the text to figure it out
 671                         if ( !$this->mSize ) {
 672                                 if ( !is_null( $this->mContent ) ) {
 673                                         $this->mSize = $this->mContent->getSize();
 674                                 } else {
 675                                         #NOTE: this should never happen if we have either text or content object!
 676                                         $this->mSize = null;
 677                                 }
 678                         }
 679
 680                         // Same for sha1
 681                         if ( $this->mSha1 === null ) {
 682                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 683                         }
 684
 685                         // force lazy init
 686                         $this->getContentModel();
 687                         $this->getContentFormat();
 688                 } else {
 689                         throw new MWException( 'Revision constructor passed invalid row format.' );
 690                 }
 691                 $this->mUnpatrolled = null;
 692         }
 693
 694         /**
 695          * Get revision ID
 696          *
 697          * @return Integer|null
 698          */
 699         public function getId() {
 700                 return $this->mId;
 701         }
 702
 703         /**
 704          * Set the revision ID
 705          *
 706          * @since 1.19
 707          * @param $id Integer
 708          */
 709         public function setId( $id ) {
 710                 $this->mId = $id;
 711         }
 712
 713         /**
 714          * Get text row ID
 715          *
 716          * @return Integer|null
 717          */
 718         public function getTextId() {
 719                 return $this->mTextId;
 720         }
 721
 722         /**
 723          * Get parent revision ID (the original previous page revision)
 724          *
 725          * @return Integer|null
 726          */
 727         public function getParentId() {
 728                 return $this->mParentId;
 729         }
 730
 731         /**
 732          * Returns the length of the text in this revision, or null if unknown.
 733          *
 734          * @return Integer|null
 735          */
 736         public function getSize() {
 737                 return $this->mSize;
 738         }
 739
 740         /**
 741          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 742          *
 743          * @return String|null
 744          */
 745         public function getSha1() {
 746                 return $this->mSha1;
 747         }
 748
 749         /**
 750          * Returns the title of the page associated with this entry or null.
 751          *
 752          * Will do a query, when title is not set and id is given.
 753          *
 754          * @return Title|null
 755          */
 756         public function getTitle() {
 757                 if ( isset( $this->mTitle ) ) {
 758                         return $this->mTitle;
 759                 }
 760                 if ( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 761                         $dbr = wfGetDB( DB_SLAVE );
 762                         $row = $dbr->selectRow(
 763                                 array( 'page', 'revision' ),
 764                                 self::selectPageFields(),
 765                                 array( 'page_id=rev_page',
 766                                         'rev_id' => $this->mId ),
 767                                 __METHOD__ );
 768                         if ( $row ) {
 769                                 $this->mTitle = Title::newFromRow( $row );
 770                         }
 771                 }
 772
 773                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 774                         $this->mTitle = Title::newFromID( $this->mPage );
 775                 }
 776
 777                 return $this->mTitle;
 778         }
 779
 780         /**
 781          * Set the title of the revision
 782          *
 783          * @param $title Title
 784          */
 785         public function setTitle( $title ) {
 786                 $this->mTitle = $title;
 787         }
 788
 789         /**
 790          * Get the page ID
 791          *
 792          * @return Integer|null
 793          */
 794         public function getPage() {
 795                 return $this->mPage;
 796         }
 797
 798         /**
 799          * Fetch revision's user id if it's available to the specified audience.
 800          * If the specified audience does not have access to it, zero will be
 801          * returned.
 802          *
 803          * @param $audience Integer: one of:
 804          *      Revision::FOR_PUBLIC       to be displayed to all users
 805          *      Revision::FOR_THIS_USER    to be displayed to the given user
 806          *      Revision::RAW              get the ID regardless of permissions
 807          * @param $user User object to check for, only if FOR_THIS_USER is passed
 808          *              to the $audience parameter
 809          * @return Integer
 810          */
 811         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 812                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 813                         return 0;
 814                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 815                         return 0;
 816                 } else {
 817                         return $this->mUser;
 818                 }
 819         }
 820
 821         /**
 822          * Fetch revision's user id without regard for the current user's permissions
 823          *
 824          * @return String
 825          */
 826         public function getRawUser() {
 827                 return $this->mUser;
 828         }
 829
 830         /**
 831          * Fetch revision's username if it's available to the specified audience.
 832          * If the specified audience does not have access to the username, an
 833          * empty string will be returned.
 834          *
 835          * @param $audience Integer: one of:
 836          *      Revision::FOR_PUBLIC       to be displayed to all users
 837          *      Revision::FOR_THIS_USER    to be displayed to the given user
 838          *      Revision::RAW              get the text regardless of permissions
 839          * @param $user User object to check for, only if FOR_THIS_USER is passed
 840          *              to the $audience parameter
 841          * @return string
 842          */
 843         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 844                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 845                         return '';
 846                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 847                         return '';
 848                 } else {
 849                         return $this->getRawUserText();
 850                 }
 851         }
 852
 853         /**
 854          * Fetch revision's username without regard for view restrictions
 855          *
 856          * @return String
 857          */
 858         public function getRawUserText() {
 859                 if ( $this->mUserText === null ) {
 860                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 861                         if ( $this->mUserText === false ) {
 862                                 # This shouldn't happen, but it can if the wiki was recovered
 863                                 # via importing revs and there is no user table entry yet.
 864                                 $this->mUserText = $this->mOrigUserText;
 865                         }
 866                 }
 867                 return $this->mUserText;
 868         }
 869
 870         /**
 871          * Fetch revision comment if it's available to the specified audience.
 872          * If the specified audience does not have access to the comment, an
 873          * empty string will be returned.
 874          *
 875          * @param $audience Integer: one of:
 876          *      Revision::FOR_PUBLIC       to be displayed to all users
 877          *      Revision::FOR_THIS_USER    to be displayed to the given user
 878          *      Revision::RAW              get the text regardless of permissions
 879          * @param $user User object to check for, only if FOR_THIS_USER is passed
 880          *              to the $audience parameter
 881          * @return String
 882          */
 883         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 884                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 885                         return '';
 886                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 887                         return '';
 888                 } else {
 889                         return $this->mComment;
 890                 }
 891         }
 892
 893         /**
 894          * Fetch revision comment without regard for the current user's permissions
 895          *
 896          * @return String
 897          */
 898         public function getRawComment() {
 899                 return $this->mComment;
 900         }
 901
 902         /**
 903          * @return Boolean
 904          */
 905         public function isMinor() {
 906                 return (bool)$this->mMinorEdit;
 907         }
 908
 909         /**
 910          * @return integer rcid of the unpatrolled row, zero if there isn't one
 911          */
 912         public function isUnpatrolled() {
 913                 if ( $this->mUnpatrolled !== null ) {
 914                         return $this->mUnpatrolled;
 915                 }
 916                 $rc = $this->getRecentChange();
 917                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 918                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 919                 } else {
 920                         $this->mUnpatrolled = 0;
 921                 }
 922                 return $this->mUnpatrolled;
 923         }
 924
 925         /**
 926          * Get the RC object belonging to the current revision, if there's one
 927          *
 928          * @since 1.22
 929          * @return RecentChange|null
 930          */
 931         public function getRecentChange() {
 932                 $dbr = wfGetDB( DB_SLAVE );
 933                 return RecentChange::newFromConds(
 934                         array(
 935                                 'rc_user_text' => $this->getRawUserText(),
 936                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
 937                                 'rc_this_oldid' => $this->getId()
 938                         ),
 939                         __METHOD__
 940                 );
 941         }
 942
 943         /**
 944          * @param int $field one of DELETED_* bitfield constants
 945          *
 946          * @return Boolean
 947          */
 948         public function isDeleted( $field ) {
 949                 return ( $this->mDeleted & $field ) == $field;
 950         }
 951
 952         /**
 953          * Get the deletion bitfield of the revision
 954          *
 955          * @return int
 956          */
 957         public function getVisibility() {
 958                 return (int)$this->mDeleted;
 959         }
 960
 961         /**
 962          * Fetch revision text if it's available to the specified audience.
 963          * If the specified audience does not have the ability to view this
 964          * revision, an empty string will be returned.
 965          *
 966          * @param $audience Integer: one of:
 967          *      Revision::FOR_PUBLIC       to be displayed to all users
 968          *      Revision::FOR_THIS_USER    to be displayed to the given user
 969          *      Revision::RAW              get the text regardless of permissions
 970          * @param $user User object to check for, only if FOR_THIS_USER is passed
 971          *              to the $audience parameter
 972          *
 973          * @deprecated in 1.21, use getContent() instead
 974          * @todo Replace usage in core
 975          * @return String
 976          */
 977         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 978                 ContentHandler::deprecated( __METHOD__, '1.21' );
 979
 980                 $content = $this->getContent( $audience, $user );
 981                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 982         }
 983
 984         /**
 985          * Fetch revision content if it's available to the specified audience.
 986          * If the specified audience does not have the ability to view this
 987          * revision, null will be returned.
 988          *
 989          * @param $audience Integer: one of:
 990          *      Revision::FOR_PUBLIC       to be displayed to all users
 991          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 992          *      Revision::RAW              get the text regardless of permissions
 993          * @param $user User object to check for, only if FOR_THIS_USER is passed
 994          *              to the $audience parameter
 995          * @since 1.21
 996          * @return Content|null
 997          */
 998         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 999                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1000                         return null;
1001                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1002                         return null;
1003                 } else {
1004                         return $this->getContentInternal();
1005                 }
1006         }
1007
1008         /**
1009          * Alias for getText(Revision::FOR_THIS_USER)
1010          *
1011          * @deprecated since 1.17
1012          * @return String
1013          */
1014         public function revText() {
1015                 wfDeprecated( __METHOD__, '1.17' );
1016                 return $this->getText( self::FOR_THIS_USER );
1017         }
1018
1019         /**
1020          * Fetch revision text without regard for view restrictions
1021          *
1022          * @return String
1023          *
1024          * @deprecated since 1.21. Instead, use Revision::getContent( Revision::RAW )
1025          *                         or Revision::getSerializedData() as appropriate.
1026          */
1027         public function getRawText() {
1028                 ContentHandler::deprecated( __METHOD__, "1.21" );
1029                 return $this->getText( self::RAW );
1030         }
1031
1032         /**
1033          * Fetch original serialized data without regard for view restrictions
1034          *
1035          * @since 1.21
1036          * @return String
1037          */
1038         public function getSerializedData() {
1039                 if ( is_null( $this->mText ) ) {
1040                         $this->mText = $this->loadText();
1041                 }
1042
1043                 return $this->mText;
1044         }
1045
1046         /**
1047          * Gets the content object for the revision (or null on failure).
1048          *
1049          * Note that for mutable Content objects, each call to this method will return a
1050          * fresh clone.
1051          *
1052          * @since 1.21
1053          * @return Content|null the Revision's content, or null on failure.
1054          */
1055         protected function getContentInternal() {
1056                 if ( is_null( $this->mContent ) ) {
1057                         // Revision is immutable. Load on demand:
1058                         if ( is_null( $this->mText ) ) {
1059                                 $this->mText = $this->loadText();
1060                         }
1061
1062                         if ( $this->mText !== null && $this->mText !== false ) {
1063                                 // Unserialize content
1064                                 $handler = $this->getContentHandler();
1065                                 $format = $this->getContentFormat();
1066
1067                                 $this->mContent = $handler->unserializeContent( $this->mText, $format );
1068                         } else {
1069                                 $this->mContent = false; // negative caching!
1070                         }
1071                 }
1072
1073                 // NOTE: copy() will return $this for immutable content objects
1074                 return $this->mContent ? $this->mContent->copy() : null;
1075         }
1076
1077         /**
1078          * Returns the content model for this revision.
1079          *
1080          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
1081          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1082          * is used as a last resort.
1083          *
1084          * @return String the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
1085          **/
1086         public function getContentModel() {
1087                 if ( !$this->mContentModel ) {
1088                         $title = $this->getTitle();
1089                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
1090
1091                         assert( !empty( $this->mContentModel ) );
1092                 }
1093
1094                 return $this->mContentModel;
1095         }
1096
1097         /**
1098          * Returns the content format for this revision.
1099          *
1100          * If no content format was stored in the database, the default format for this
1101          * revision's content model is returned.
1102          *
1103          * @return String the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
1104          **/
1105         public function getContentFormat() {
1106                 if ( !$this->mContentFormat ) {
1107                         $handler = $this->getContentHandler();
1108                         $this->mContentFormat = $handler->getDefaultFormat();
1109
1110                         assert( !empty( $this->mContentFormat ) );
1111                 }
1112
1113                 return $this->mContentFormat;
1114         }
1115
1116         /**
1117          * Returns the content handler appropriate for this revision's content model.
1118          *
1119          * @throws MWException
1120          * @return ContentHandler
1121          */
1122         public function getContentHandler() {
1123                 if ( !$this->mContentHandler ) {
1124                         $model = $this->getContentModel();
1125                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1126
1127                         $format = $this->getContentFormat();
1128
1129                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1130                                 throw new MWException( "Oops, the content format $format is not supported for this content model, $model" );
1131                         }
1132                 }
1133
1134                 return $this->mContentHandler;
1135         }
1136
1137         /**
1138          * @return String
1139          */
1140         public function getTimestamp() {
1141                 return wfTimestamp( TS_MW, $this->mTimestamp );
1142         }
1143
1144         /**
1145          * @return Boolean
1146          */
1147         public function isCurrent() {
1148                 return $this->mCurrent;
1149         }
1150
1151         /**
1152          * Get previous revision for this title
1153          *
1154          * @return Revision|null
1155          */
1156         public function getPrevious() {
1157                 if ( $this->getTitle() ) {
1158                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1159                         if ( $prev ) {
1160                                 return self::newFromTitle( $this->getTitle(), $prev );
1161                         }
1162                 }
1163                 return null;
1164         }
1165
1166         /**
1167          * Get next revision for this title
1168          *
1169          * @return Revision or null
1170          */
1171         public function getNext() {
1172                 if ( $this->getTitle() ) {
1173                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1174                         if ( $next ) {
1175                                 return self::newFromTitle( $this->getTitle(), $next );
1176                         }
1177                 }
1178                 return null;
1179         }
1180
1181         /**
1182          * Get previous revision Id for this page_id
1183          * This is used to populate rev_parent_id on save
1184          *
1185          * @param $db DatabaseBase
1186          * @return Integer
1187          */
1188         private function getPreviousRevisionId( $db ) {
1189                 if ( is_null( $this->mPage ) ) {
1190                         return 0;
1191                 }
1192                 # Use page_latest if ID is not given
1193                 if ( !$this->mId ) {
1194                         $prevId = $db->selectField( 'page', 'page_latest',
1195                                 array( 'page_id' => $this->mPage ),
1196                                 __METHOD__ );
1197                 } else {
1198                         $prevId = $db->selectField( 'revision', 'rev_id',
1199                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1200                                 __METHOD__,
1201                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1202                 }
1203                 return intval( $prevId );
1204         }
1205
1206         /**
1207           * Get revision text associated with an old or archive row
1208           * $row is usually an object from wfFetchRow(), both the flags and the text
1209           * field must be included
1210           *
1211           * @param $row Object: the text data
1212           * @param string $prefix table prefix (default 'old_')
1213           * @param string|false $wiki the name of the wiki to load the revision text from
1214           *         (same as the the wiki $row was loaded from) or false to indicate the local
1215           *         wiki (this is the default). Otherwise, it must be a symbolic wiki database
1216           *         identifier as understood by the LoadBalancer class.
1217           * @return String: text the text requested or false on failure
1218           */
1219         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1220                 wfProfileIn( __METHOD__ );
1221
1222                 # Get data
1223                 $textField = $prefix . 'text';
1224                 $flagsField = $prefix . 'flags';
1225
1226                 if ( isset( $row->$flagsField ) ) {
1227                         $flags = explode( ',', $row->$flagsField );
1228                 } else {
1229                         $flags = array();
1230                 }
1231
1232                 if ( isset( $row->$textField ) ) {
1233                         $text = $row->$textField;
1234                 } else {
1235                         wfProfileOut( __METHOD__ );
1236                         return false;
1237                 }
1238
1239                 # Use external methods for external objects, text in table is URL-only then
1240                 if ( in_array( 'external', $flags ) ) {
1241                         $url = $text;
1242                         $parts = explode( '://', $url, 2 );
1243                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1244                                 wfProfileOut( __METHOD__ );
1245                                 return false;
1246                         }
1247                         $text = ExternalStore::fetchFromURL( $url, array( 'wiki' => $wiki ) );
1248                 }
1249
1250                 // If the text was fetched without an error, convert it
1251                 if ( $text !== false ) {
1252                         $text = self::decompressRevisionText( $text, $flags );
1253                 }
1254                 wfProfileOut( __METHOD__ );
1255                 return $text;
1256         }
1257
1258         /**
1259          * If $wgCompressRevisions is enabled, we will compress data.
1260          * The input string is modified in place.
1261          * Return value is the flags field: contains 'gzip' if the
1262          * data is compressed, and 'utf-8' if we're saving in UTF-8
1263          * mode.
1264          *
1265          * @param $text Mixed: reference to a text
1266          * @return String
1267          */
1268         public static function compressRevisionText( &$text ) {
1269                 global $wgCompressRevisions;
1270                 $flags = array();
1271
1272                 # Revisions not marked this way will be converted
1273                 # on load if $wgLegacyCharset is set in the future.
1274                 $flags[] = 'utf-8';
1275
1276                 if ( $wgCompressRevisions ) {
1277                         if ( function_exists( 'gzdeflate' ) ) {
1278                                 $text = gzdeflate( $text );
1279                                 $flags[] = 'gzip';
1280                         } else {
1281                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1282                         }
1283                 }
1284                 return implode( ',', $flags );
1285         }
1286
1287         /**
1288          * Re-converts revision text according to it's flags.
1289          *
1290          * @param $text Mixed: reference to a text
1291          * @param $flags array: compression flags
1292          * @return String|bool decompressed text, or false on failure
1293          */
1294         public static function decompressRevisionText( $text, $flags ) {
1295                 if ( in_array( 'gzip', $flags ) ) {
1296                         # Deal with optional compression of archived pages.
1297                         # This can be done periodically via maintenance/compressOld.php, and
1298                         # as pages are saved if $wgCompressRevisions is set.
1299                         $text = gzinflate( $text );
1300                 }
1301
1302                 if ( in_array( 'object', $flags ) ) {
1303                         # Generic compressed storage
1304                         $obj = unserialize( $text );
1305                         if ( !is_object( $obj ) ) {
1306                                 // Invalid object
1307                                 return false;
1308                         }
1309                         $text = $obj->getText();
1310                 }
1311
1312                 global $wgLegacyEncoding;
1313                 if ( $text !== false && $wgLegacyEncoding
1314                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1315                 {
1316                         # Old revisions kept around in a legacy encoding?
1317                         # Upconvert on demand.
1318                         # ("utf8" checked for compatibility with some broken
1319                         #  conversion scripts 2008-12-30)
1320                         global $wgContLang;
1321                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1322                 }
1323
1324                 return $text;
1325         }
1326
1327         /**
1328          * Insert a new revision into the database, returning the new revision ID
1329          * number on success and dies horribly on failure.
1330          *
1331          * @param $dbw DatabaseBase: (master connection)
1332          * @throws MWException
1333          * @return Integer
1334          */
1335         public function insertOn( $dbw ) {
1336                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1337
1338                 wfProfileIn( __METHOD__ );
1339
1340                 $this->checkContentModel();
1341
1342                 $data = $this->mText;
1343                 $flags = self::compressRevisionText( $data );
1344
1345                 # Write to external storage if required
1346                 if ( $wgDefaultExternalStore ) {
1347                         // Store and get the URL
1348                         $data = ExternalStore::insertToDefault( $data );
1349                         if ( !$data ) {
1350                                 wfProfileOut( __METHOD__ );
1351                                 throw new MWException( "Unable to store text to external storage" );
1352                         }
1353                         if ( $flags ) {
1354                                 $flags .= ',';
1355                         }
1356                         $flags .= 'external';
1357                 }
1358
1359                 # Record the text (or external storage URL) to the text table
1360                 if ( !isset( $this->mTextId ) ) {
1361                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1362                         $dbw->insert( 'text',
1363                                 array(
1364                                         'old_id' => $old_id,
1365                                         'old_text' => $data,
1366                                         'old_flags' => $flags,
1367                                 ), __METHOD__
1368                         );
1369                         $this->mTextId = $dbw->insertId();
1370                 }
1371
1372                 if ( $this->mComment === null ) {
1373                         $this->mComment = "";
1374                 }
1375
1376                 # Record the edit in revisions
1377                 $rev_id = isset( $this->mId )
1378                         ? $this->mId
1379                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1380                 $row = array(
1381                         'rev_id'         => $rev_id,
1382                         'rev_page'       => $this->mPage,
1383                         'rev_text_id'    => $this->mTextId,
1384                         'rev_comment'    => $this->mComment,
1385                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1386                         'rev_user'       => $this->mUser,
1387                         'rev_user_text'  => $this->mUserText,
1388                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1389                         'rev_deleted'    => $this->mDeleted,
1390                         'rev_len'        => $this->mSize,
1391                         'rev_parent_id'  => is_null( $this->mParentId )
1392                                 ? $this->getPreviousRevisionId( $dbw )
1393                                 : $this->mParentId,
1394                         'rev_sha1'       => is_null( $this->mSha1 )
1395                                 ? Revision::base36Sha1( $this->mText )
1396                                 : $this->mSha1,
1397                 );
1398
1399                 if ( $wgContentHandlerUseDB ) {
1400                         //NOTE: Store null for the default model and format, to save space.
1401                         //XXX: Makes the DB sensitive to changed defaults. Make this behavior optional? Only in miser mode?
1402
1403                         $model = $this->getContentModel();
1404                         $format = $this->getContentFormat();
1405
1406                         $title = $this->getTitle();
1407
1408                         if ( $title === null ) {
1409                                 wfProfileOut( __METHOD__ );
1410                                 throw new MWException( "Insufficient information to determine the title of the 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 = !is_null( $rev_id ) ? $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, all revisions must use the default content model and format.
1447
1448                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1449                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1450                         $defaultFormat = $defaultHandler->getDefaultFormat();
1451
1452                         if ( $this->getContentModel() != $defaultModel ) {
1453                                 $t = $title->getPrefixedDBkey();
1454
1455                                 throw new MWException( "Can't save non-default content model with \$wgContentHandlerUseDB disabled: "
1456                                                                                 . "model is $model , default for $t is $defaultModel" );
1457                         }
1458
1459                         if ( $this->getContentFormat() != $defaultFormat ) {
1460                                 $t = $title->getPrefixedDBkey();
1461
1462                                 throw new MWException( "Can't use non-default content format with \$wgContentHandlerUseDB disabled: "
1463                                                                                 . "format is $format, default for $t is $defaultFormat" );
1464                         }
1465                 }
1466
1467                 $content = $this->getContent( Revision::RAW );
1468
1469                 if ( !$content || !$content->isValid() ) {
1470                         $t = $title->getPrefixedDBkey();
1471
1472                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1473                 }
1474         }
1475
1476         /**
1477          * Get the base 36 SHA-1 value for a string of text
1478          * @param $text String
1479          * @return String
1480          */
1481         public static function base36Sha1( $text ) {
1482                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1483         }
1484
1485         /**
1486          * Lazy-load the revision's text.
1487          * Currently hardcoded to the 'text' table storage engine.
1488          *
1489          * @return String|bool the revision's text, or false on failure
1490          */
1491         protected function loadText() {
1492                 wfProfileIn( __METHOD__ );
1493
1494                 // Caching may be beneficial for massive use of external storage
1495                 global $wgRevisionCacheExpiry, $wgMemc;
1496                 $textId = $this->getTextId();
1497                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1498                 if ( $wgRevisionCacheExpiry ) {
1499                         $text = $wgMemc->get( $key );
1500                         if ( is_string( $text ) ) {
1501                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1502                                 wfProfileOut( __METHOD__ );
1503                                 return $text;
1504                         }
1505                 }
1506
1507                 // If we kept data for lazy extraction, use it now...
1508                 if ( isset( $this->mTextRow ) ) {
1509                         $row = $this->mTextRow;
1510                         $this->mTextRow = null;
1511                 } else {
1512                         $row = null;
1513                 }
1514
1515                 if ( !$row ) {
1516                         // Text data is immutable; check slaves first.
1517                         $dbr = wfGetDB( DB_SLAVE );
1518                         $row = $dbr->selectRow( 'text',
1519                                 array( 'old_text', 'old_flags' ),
1520                                 array( 'old_id' => $textId ),
1521                                 __METHOD__ );
1522                 }
1523
1524                 // Fallback to the master in case of slave lag. Also use FOR UPDATE if it was
1525                 // used to fetch this revision to avoid missing the row due to REPEATABLE-READ.
1526                 $forUpdate = ( $this->mQueryFlags & self::READ_LOCKING == self::READ_LOCKING );
1527                 if ( !$row && ( $forUpdate || wfGetLB()->getServerCount() > 1 ) ) {
1528                         $dbw = wfGetDB( DB_MASTER );
1529                         $row = $dbw->selectRow( 'text',
1530                                 array( 'old_text', 'old_flags' ),
1531                                 array( 'old_id' => $textId ),
1532                                 __METHOD__,
1533                                 $forUpdate ? array( 'FOR UPDATE' ) : array() );
1534                 }
1535
1536                 if ( !$row ) {
1537                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1538                 }
1539
1540                 $text = self::getRevisionText( $row );
1541                 if ( $row && $text === false ) {
1542                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1543                 }
1544
1545                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1546                 if ( $wgRevisionCacheExpiry && $text !== false ) {
1547                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1548                 }
1549
1550                 wfProfileOut( __METHOD__ );
1551
1552                 return $text;
1553         }
1554
1555         /**
1556          * Create a new null-revision for insertion into a page's
1557          * history. This will not re-save the text, but simply refer
1558          * to the text from the previous version.
1559          *
1560          * Such revisions can for instance identify page rename
1561          * operations and other such meta-modifications.
1562          *
1563          * @param $dbw DatabaseBase
1564          * @param $pageId Integer: ID number of the page to read from
1565          * @param string $summary revision's summary
1566          * @param $minor Boolean: whether the revision should be considered as minor
1567          * @return Revision|null on error
1568          */
1569         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1570                 global $wgContentHandlerUseDB;
1571
1572                 wfProfileIn( __METHOD__ );
1573
1574                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1575                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1576
1577                 if ( $wgContentHandlerUseDB ) {
1578                         $fields[] = 'rev_content_model';
1579                         $fields[] = 'rev_content_format';
1580                 }
1581
1582                 $current = $dbw->selectRow(
1583                         array( 'page', 'revision' ),
1584                         $fields,
1585                         array(
1586                                 'page_id' => $pageId,
1587                                 'page_latest=rev_id',
1588                                 ),
1589                         __METHOD__ );
1590
1591                 if ( $current ) {
1592                         $row = array(
1593                                 'page'       => $pageId,
1594                                 'comment'    => $summary,
1595                                 'minor_edit' => $minor,
1596                                 'text_id'    => $current->rev_text_id,
1597                                 'parent_id'  => $current->page_latest,
1598                                 'len'        => $current->rev_len,
1599                                 'sha1'       => $current->rev_sha1
1600                         );
1601
1602                         if ( $wgContentHandlerUseDB ) {
1603                                 $row['content_model'] = $current->rev_content_model;
1604                                 $row['content_format'] = $current->rev_content_format;
1605                         }
1606
1607                         $revision = new Revision( $row );
1608                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1609                 } else {
1610                         $revision = null;
1611                 }
1612
1613                 wfProfileOut( __METHOD__ );
1614                 return $revision;
1615         }
1616
1617         /**
1618          * Determine if the current user is allowed to view a particular
1619          * field of this revision, if it's marked as deleted.
1620          *
1621          * @param $field Integer:one of self::DELETED_TEXT,
1622          *                              self::DELETED_COMMENT,
1623          *                              self::DELETED_USER
1624          * @param $user User object to check, or null to use $wgUser
1625          * @return Boolean
1626          */
1627         public function userCan( $field, User $user = null ) {
1628                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1629         }
1630
1631         /**
1632          * Determine if the current user is allowed to view a particular
1633          * field of this revision, if it's marked as deleted. This is used
1634          * by various classes to avoid duplication.
1635          *
1636          * @param $bitfield Integer: current field
1637          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1638          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1639          *                               self::DELETED_USER = File::DELETED_USER
1640          * @param $user User object to check, or null to use $wgUser
1641          * @return Boolean
1642          */
1643         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1644                 if ( $bitfield & $field ) { // aspect is deleted
1645                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1646                                 $permission = 'suppressrevision';
1647                         } elseif ( $field & self::DELETED_TEXT ) {
1648                                 $permission = 'deletedtext';
1649                         } else {
1650                                 $permission = 'deletedhistory';
1651                         }
1652                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1653                         if ( $user === null ) {
1654                                 global $wgUser;
1655                                 $user = $wgUser;
1656                         }
1657                         return $user->isAllowed( $permission );
1658                 } else {
1659                         return true;
1660                 }
1661         }
1662
1663         /**
1664          * Get rev_timestamp from rev_id, without loading the rest of the row
1665          *
1666          * @param $title Title
1667          * @param $id Integer
1668          * @return String
1669          */
1670         static function getTimestampFromId( $title, $id ) {
1671                 $dbr = wfGetDB( DB_SLAVE );
1672                 // Casting fix for databases that can't take '' for rev_id
1673                 if ( $id == '' ) {
1674                         $id = 0;
1675                 }
1676                 $conds = array( 'rev_id' => $id );
1677                 $conds['rev_page'] = $title->getArticleID();
1678                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1679                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1680                         # Not in slave, try master
1681                         $dbw = wfGetDB( DB_MASTER );
1682                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1683                 }
1684                 return wfTimestamp( TS_MW, $timestamp );
1685         }
1686
1687         /**
1688          * Get count of revisions per page...not very efficient
1689          *
1690          * @param $db DatabaseBase
1691          * @param $id Integer: page id
1692          * @return Integer
1693          */
1694         static function countByPageId( $db, $id ) {
1695                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1696                         array( 'rev_page' => $id ), __METHOD__ );
1697                 if ( $row ) {
1698                         return $row->revCount;
1699                 }
1700                 return 0;
1701         }
1702
1703         /**
1704          * Get count of revisions per page...not very efficient
1705          *
1706          * @param $db DatabaseBase
1707          * @param $title Title
1708          * @return Integer
1709          */
1710         static function countByTitle( $db, $title ) {
1711                 $id = $title->getArticleID();
1712                 if ( $id ) {
1713                         return self::countByPageId( $db, $id );
1714                 }
1715                 return 0;
1716         }
1717
1718         /**
1719          * Check if no edits were made by other users since
1720          * the time a user started editing the page. Limit to
1721          * 50 revisions for the sake of performance.
1722          *
1723          * @since 1.20
1724          *
1725          * @param DatabaseBase|int $db the Database to perform the check on. May be given as a Database object or
1726          *        a database identifier usable with wfGetDB.
1727          * @param int $pageId the ID of the page in question
1728          * @param int $userId the ID of the user in question
1729          * @param string $since look at edits since this time
1730          *
1731          * @return bool True if the given user was the only one to edit since the given timestamp
1732          */
1733         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1734                 if ( !$userId ) {
1735                         return false;
1736                 }
1737
1738                 if ( is_int( $db ) ) {
1739                         $db = wfGetDB( $db );
1740                 }
1741
1742                 $res = $db->select( 'revision',
1743                         'rev_user',
1744                         array(
1745                                 'rev_page' => $pageId,
1746                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1747                         ),
1748                         __METHOD__,
1749                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1750                 foreach ( $res as $row ) {
1751                         if ( $row->rev_user != $userId ) {
1752                                 return false;
1753                         }
1754                 }
1755                 return true;
1756         }
1757 }