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         // Revision deletion constants
  65         const DELETED_TEXT = 1;
  66         const DELETED_COMMENT = 2;
  67         const DELETED_USER = 4;
  68         const DELETED_RESTRICTED = 8;
  69         const SUPPRESSED_USER = 12; // convenience
  70
  71         // Audience options for accessors
  72         const FOR_PUBLIC = 1;
  73         const FOR_THIS_USER = 2;
  74         const RAW = 3;
  75
  76         /**
  77          * Load a page revision from a given revision ID number.
  78          * Returns null if no such revision can be found.
  79          *
  80          * $flags include:
  81          *      Revision::READ_LATEST  : Select the data from the master
  82          *      Revision::READ_LOCKING : Select & lock the data from the master
  83          *
  84          * @param $id Integer
  85          * @param $flags Integer (optional)
  86          * @return Revision or null
  87          */
  88         public static function newFromId( $id, $flags = 0 ) {
  89                 return self::newFromConds( array( 'rev_id' => intval( $id ) ), $flags );
  90         }
  91
  92         /**
  93          * Load either the current, or a specified, revision
  94          * that's attached to a given title. If not attached
  95          * to that title, will return null.
  96          *
  97          * $flags include:
  98          *      Revision::READ_LATEST  : Select the data from the master
  99          *      Revision::READ_LOCKING : Select & lock the data from the master
 100          *
 101          * @param $title Title
 102          * @param $id Integer (optional)
 103          * @param $flags Integer Bitfield (optional)
 104          * @return Revision or null
 105          */
 106         public static function newFromTitle( $title, $id = 0, $flags = 0 ) {
 107                 $conds = array(
 108                         'page_namespace' => $title->getNamespace(),
 109                         'page_title'     => $title->getDBkey()
 110                 );
 111                 if ( $id ) {
 112                         // Use the specified ID
 113                         $conds['rev_id'] = $id;
 114                 } else {
 115                         // Use a join to get the latest revision
 116                         $conds[] = 'rev_id=page_latest';
 117                 }
 118                 return self::newFromConds( $conds, (int)$flags );
 119         }
 120
 121         /**
 122          * Load either the current, or a specified, revision
 123          * that's attached to a given page ID.
 124          * Returns null if no such revision can be found.
 125          *
 126          * $flags include:
 127          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 128          *      Revision::READ_LOCKING : Select & lock the data from the master
 129          *
 130          * @param $revId Integer
 131          * @param $pageId Integer (optional)
 132          * @param $flags Integer Bitfield (optional)
 133          * @return Revision or null
 134          */
 135         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 136                 $conds = array( 'page_id' => $pageId );
 137                 if ( $revId ) {
 138                         $conds['rev_id'] = $revId;
 139                 } else {
 140                         // Use a join to get the latest revision
 141                         $conds[] = 'rev_id = page_latest';
 142                 }
 143                 return self::newFromConds( $conds, (int)$flags );
 144         }
 145
 146         /**
 147          * Make a fake revision object from an archive table row. This is queried
 148          * for permissions or even inserted (as in Special:Undelete)
 149          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 150          *
 151          * @param $row
 152          * @param $overrides array
 153          *
 154          * @throws MWException
 155          * @return Revision
 156          */
 157         public static function newFromArchiveRow( $row, $overrides = array() ) {
 158                 global $wgContentHandlerUseDB;
 159
 160                 $attribs = $overrides + array(
 161                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 162                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 163                         'comment'    => $row->ar_comment,
 164                         'user'       => $row->ar_user,
 165                         'user_text'  => $row->ar_user_text,
 166                         'timestamp'  => $row->ar_timestamp,
 167                         'minor_edit' => $row->ar_minor_edit,
 168                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 169                         'deleted'    => $row->ar_deleted,
 170                         'len'        => $row->ar_len,
 171                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 172                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 173                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 174                 );
 175
 176                 if ( !$wgContentHandlerUseDB ) {
 177                         unset( $attribs['content_model'] );
 178                         unset( $attribs['content_format'] );
 179                 }
 180
 181                 if ( !isset( $attribs['title'] )
 182                         && isset( $row->ar_namespace )
 183                         && isset( $row->ar_title ) ) {
 184
 185                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 186                 }
 187
 188                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 189                         // Pre-1.5 ar_text row
 190                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 191                         if ( $attribs['text'] === false ) {
 192                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 193                         }
 194                 }
 195                 return new self( $attribs );
 196         }
 197
 198         /**
 199          * @since 1.19
 200          *
 201          * @param $row
 202          * @return Revision
 203          */
 204         public static function newFromRow( $row ) {
 205                 return new self( $row );
 206         }
 207
 208         /**
 209          * Load a page revision from a given revision ID number.
 210          * Returns null if no such revision can be found.
 211          *
 212          * @param $db DatabaseBase
 213          * @param $id Integer
 214          * @return Revision or null
 215          */
 216         public static function loadFromId( $db, $id ) {
 217                 return self::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 218         }
 219
 220         /**
 221          * Load either the current, or a specified, revision
 222          * that's attached to a given page. If not attached
 223          * to that page, will return null.
 224          *
 225          * @param $db DatabaseBase
 226          * @param $pageid Integer
 227          * @param $id Integer
 228          * @return Revision or null
 229          */
 230         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 231                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 232                 if( $id ) {
 233                         $conds['rev_id'] = intval( $id );
 234                 } else {
 235                         $conds[] = 'rev_id=page_latest';
 236                 }
 237                 return self::loadFromConds( $db, $conds );
 238         }
 239
 240         /**
 241          * Load either the current, or a specified, revision
 242          * that's attached to a given page. If not attached
 243          * to that page, will return null.
 244          *
 245          * @param $db DatabaseBase
 246          * @param $title Title
 247          * @param $id Integer
 248          * @return Revision or null
 249          */
 250         public static function loadFromTitle( $db, $title, $id = 0 ) {
 251                 if( $id ) {
 252                         $matchId = intval( $id );
 253                 } else {
 254                         $matchId = 'page_latest';
 255                 }
 256                 return self::loadFromConds( $db,
 257                         array( "rev_id=$matchId",
 258                                    'page_namespace' => $title->getNamespace(),
 259                                    'page_title'     => $title->getDBkey() )
 260                 );
 261         }
 262
 263         /**
 264          * Load the revision for the given title with the given timestamp.
 265          * WARNING: Timestamps may in some circumstances not be unique,
 266          * so this isn't the best key to use.
 267          *
 268          * @param $db DatabaseBase
 269          * @param $title Title
 270          * @param $timestamp String
 271          * @return Revision or null
 272          */
 273         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 274                 return self::loadFromConds( $db,
 275                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 276                                    'page_namespace' => $title->getNamespace(),
 277                                    'page_title'     => $title->getDBkey() )
 278                 );
 279         }
 280
 281         /**
 282          * Given a set of conditions, fetch a revision.
 283          *
 284          * @param $conditions Array
 285          * @param $flags integer (optional)
 286          * @return Revision or null
 287          */
 288         private static function newFromConds( $conditions, $flags = 0 ) {
 289                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 290                 $rev = self::loadFromConds( $db, $conditions, $flags );
 291                 if ( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 292                         if ( !( $flags & self::READ_LATEST ) ) {
 293                                 $dbw = wfGetDB( DB_MASTER );
 294                                 $rev = self::loadFromConds( $dbw, $conditions, $flags );
 295                         }
 296                 }
 297                 return $rev;
 298         }
 299
 300         /**
 301          * Given a set of conditions, fetch a revision from
 302          * the given database connection.
 303          *
 304          * @param $db DatabaseBase
 305          * @param $conditions Array
 306          * @param $flags integer (optional)
 307          * @return Revision or null
 308          */
 309         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 310                 $res = self::fetchFromConds( $db, $conditions, $flags );
 311                 if( $res ) {
 312                         $row = $res->fetchObject();
 313                         if( $row ) {
 314                                 $ret = new Revision( $row );
 315                                 return $ret;
 316                         }
 317                 }
 318                 $ret = null;
 319                 return $ret;
 320         }
 321
 322         /**
 323          * Return a wrapper for a series of database rows to
 324          * fetch all of a given page's revisions in turn.
 325          * Each row can be fed to the constructor to get objects.
 326          *
 327          * @param $title Title
 328          * @return ResultWrapper
 329          */
 330         public static function fetchRevision( $title ) {
 331                 return self::fetchFromConds(
 332                         wfGetDB( DB_SLAVE ),
 333                         array( 'rev_id=page_latest',
 334                                    'page_namespace' => $title->getNamespace(),
 335                                    'page_title'     => $title->getDBkey() )
 336                 );
 337         }
 338
 339         /**
 340          * Given a set of conditions, return a ResultWrapper
 341          * which will return matching database rows with the
 342          * fields necessary to build Revision objects.
 343          *
 344          * @param $db DatabaseBase
 345          * @param $conditions Array
 346          * @param $flags integer (optional)
 347          * @return ResultWrapper
 348          */
 349         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 350                 $fields = array_merge(
 351                         self::selectFields(),
 352                         self::selectPageFields(),
 353                         self::selectUserFields()
 354                 );
 355                 $options = array( 'LIMIT' => 1 );
 356                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 357                         $options[] = 'FOR UPDATE';
 358                 }
 359                 return $db->select(
 360                         array( 'revision', 'page', 'user' ),
 361                         $fields,
 362                         $conditions,
 363                         __METHOD__,
 364                         $options,
 365                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 366                 );
 367         }
 368
 369         /**
 370          * Return the value of a select() JOIN conds array for the user table.
 371          * This will get user table rows for logged-in users.
 372          * @since 1.19
 373          * @return Array
 374          */
 375         public static function userJoinCond() {
 376                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 377         }
 378
 379         /**
 380          * Return the value of a select() page conds array for the paeg table.
 381          * This will assure that the revision(s) are not orphaned from live pages.
 382          * @since 1.19
 383          * @return Array
 384          */
 385         public static function pageJoinCond() {
 386                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 387         }
 388
 389         /**
 390          * Return the list of revision fields that should be selected to create
 391          * a new revision.
 392          * @return array
 393          */
 394         public static function selectFields() {
 395                 global $wgContentHandlerUseDB;
 396
 397                 $fields = array(
 398                         'rev_id',
 399                         'rev_page',
 400                         'rev_text_id',
 401                         'rev_timestamp',
 402                         'rev_comment',
 403                         'rev_user_text',
 404                         'rev_user',
 405                         'rev_minor_edit',
 406                         'rev_deleted',
 407                         'rev_len',
 408                         'rev_parent_id',
 409                         'rev_sha1',
 410                 );
 411
 412                 if ( $wgContentHandlerUseDB ) {
 413                         $fields[] = 'rev_content_format';
 414                         $fields[] = 'rev_content_model';
 415                 }
 416
 417                 return $fields;
 418         }
 419
 420         /**
 421          * Return the list of text fields that should be selected to read the
 422          * revision text
 423          * @return array
 424          */
 425         public static function selectTextFields() {
 426                 return array(
 427                         'old_text',
 428                         'old_flags'
 429                 );
 430         }
 431
 432         /**
 433          * Return the list of page fields that should be selected from page table
 434          * @return array
 435          */
 436         public static function selectPageFields() {
 437                 return array(
 438                         'page_namespace',
 439                         'page_title',
 440                         'page_id',
 441                         'page_latest',
 442                         'page_is_redirect',
 443                         'page_len',
 444                 );
 445         }
 446
 447         /**
 448          * Return the list of user fields that should be selected from user table
 449          * @return array
 450          */
 451         public static function selectUserFields() {
 452                 return array( 'user_name' );
 453         }
 454
 455         /**
 456          * Do a batched query to get the parent revision lengths
 457          * @param $db DatabaseBase
 458          * @param $revIds Array
 459          * @return array
 460          */
 461         public static function getParentLengths( $db, array $revIds ) {
 462                 $revLens = array();
 463                 if ( !$revIds ) {
 464                         return $revLens; // empty
 465                 }
 466                 wfProfileIn( __METHOD__ );
 467                 $res = $db->select( 'revision',
 468                         array( 'rev_id', 'rev_len' ),
 469                         array( 'rev_id' => $revIds ),
 470                         __METHOD__ );
 471                 foreach ( $res as $row ) {
 472                         $revLens[$row->rev_id] = $row->rev_len;
 473                 }
 474                 wfProfileOut( __METHOD__ );
 475                 return $revLens;
 476         }
 477
 478         /**
 479          * Constructor
 480          *
 481          * @param $row Mixed: either a database row or an array
 482          * @throws MWException
 483          * @access private
 484          */
 485         function __construct( $row ) {
 486                 if( is_object( $row ) ) {
 487                         $this->mId        = intval( $row->rev_id );
 488                         $this->mPage      = intval( $row->rev_page );
 489                         $this->mTextId    = intval( $row->rev_text_id );
 490                         $this->mComment   =         $row->rev_comment;
 491                         $this->mUser      = intval( $row->rev_user );
 492                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 493                         $this->mTimestamp =         $row->rev_timestamp;
 494                         $this->mDeleted   = intval( $row->rev_deleted );
 495
 496                         if( !isset( $row->rev_parent_id ) ) {
 497                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 498                         } else {
 499                                 $this->mParentId  = intval( $row->rev_parent_id );
 500                         }
 501
 502                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 503                                 $this->mSize = null;
 504                         } else {
 505                                 $this->mSize = intval( $row->rev_len );
 506                         }
 507
 508                         if ( !isset( $row->rev_sha1 ) ) {
 509                                 $this->mSha1 = null;
 510                         } else {
 511                                 $this->mSha1 = $row->rev_sha1;
 512                         }
 513
 514                         if( isset( $row->page_latest ) ) {
 515                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 516                                 $this->mTitle = Title::newFromRow( $row );
 517                         } else {
 518                                 $this->mCurrent = false;
 519                                 $this->mTitle = null;
 520                         }
 521
 522                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 523                                 $this->mContentModel = null; # determine on demand if needed
 524                         } else {
 525                                 $this->mContentModel = strval( $row->rev_content_model );
 526                         }
 527
 528                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 529                                 $this->mContentFormat = null; # determine on demand if needed
 530                         } else {
 531                                 $this->mContentFormat = strval( $row->rev_content_format );
 532                         }
 533
 534                         // Lazy extraction...
 535                         $this->mText      = null;
 536                         if( isset( $row->old_text ) ) {
 537                                 $this->mTextRow = $row;
 538                         } else {
 539                                 // 'text' table row entry will be lazy-loaded
 540                                 $this->mTextRow = null;
 541                         }
 542
 543                         // Use user_name for users and rev_user_text for IPs...
 544                         $this->mUserText = null; // lazy load if left null
 545                         if ( $this->mUser == 0 ) {
 546                                 $this->mUserText = $row->rev_user_text; // IP user
 547                         } elseif ( isset( $row->user_name ) ) {
 548                                 $this->mUserText = $row->user_name; // logged-in user
 549                         }
 550                         $this->mOrigUserText = $row->rev_user_text;
 551                 } elseif( is_array( $row ) ) {
 552                         // Build a new revision to be saved...
 553                         global $wgUser; // ugh
 554
 555
 556                         # if we have a content object, use it to set the model and type
 557                         if ( !empty( $row['content'] ) ) {
 558                                 //@todo: when is that set? test with external store setup! check out insertOn() [dk]
 559                                 if ( !empty( $row['text_id'] ) ) {
 560                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), "
 561                                                                                         . "can't serialize content object" );
 562                                 }
 563
 564                                 $row['content_model'] = $row['content']->getModel();
 565                                 # note: mContentFormat is initializes later accordingly
 566                                 # note: content is serialized later in this method!
 567                                 # also set text to null?
 568                         }
 569
 570                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 571                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 572                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 573                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 574                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 575                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 576                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 577                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 578                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 579                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 580                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 581
 582                         $this->mContentModel   = isset( $row['content_model']  )  ? strval( $row['content_model'] )  : null;
 583                         $this->mContentFormat  = isset( $row['content_format']  ) ? strval( $row['content_format'] ) : null;
 584
 585                         // Enforce spacing trimming on supplied text
 586                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 587                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 588                         $this->mTextRow   = null;
 589
 590                         $this->mTitle     = isset( $row['title']      ) ? $row['title'] : null;
 591
 592                         // if we have a Content object, override mText and mContentModel
 593                         if ( !empty( $row['content'] ) ) {
 594                                 if ( !( $row['content'] instanceof Content ) ) {
 595                                         throw new MWException( '`content` field must contain a Content object.' );
 596                                 }
 597
 598                                 $handler = $this->getContentHandler();
 599                                 $this->mContent = $row['content'];
 600
 601                                 $this->mContentModel = $this->mContent->getModel();
 602                                 $this->mContentHandler = null;
 603
 604                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 605                         } elseif ( !is_null( $this->mText ) ) {
 606                                 $handler = $this->getContentHandler();
 607                                 $this->mContent = $handler->unserializeContent( $this->mText );
 608                         }
 609
 610                         // If we have a Title object, make sure it is consistent with mPage.
 611                         if ( $this->mTitle && $this->mTitle->exists() ) {
 612                                 if ( $this->mPage === null ) {
 613                                         // if the page ID wasn't known, set it now
 614                                         $this->mPage = $this->mTitle->getArticleID();
 615                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 616                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 617                                         // but it seems worth mentioning it in the log.
 618                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID "
 619                                                         . $this->mTitle->getArticleID() . " provided by the Title object." );
 620                                 }
 621                         }
 622
 623                         $this->mCurrent   = false;
 624
 625                         // If we still have no length, see it we have the text to figure it out
 626                         if ( !$this->mSize ) {
 627                                 if ( !is_null( $this->mContent ) ) {
 628                                         $this->mSize = $this->mContent->getSize();
 629                                 } else {
 630                                         #NOTE: this should never happen if we have either text or content object!
 631                                         $this->mSize = null;
 632                                 }
 633                         }
 634
 635                         // Same for sha1
 636                         if ( $this->mSha1 === null ) {
 637                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 638                         }
 639
 640                         // force lazy init
 641                         $this->getContentModel();
 642                         $this->getContentFormat();
 643                 } else {
 644                         throw new MWException( 'Revision constructor passed invalid row format.' );
 645                 }
 646                 $this->mUnpatrolled = null;
 647         }
 648
 649         /**
 650          * Get revision ID
 651          *
 652          * @return Integer|null
 653          */
 654         public function getId() {
 655                 return $this->mId;
 656         }
 657
 658         /**
 659          * Set the revision ID
 660          *
 661          * @since 1.19
 662          * @param $id Integer
 663          */
 664         public function setId( $id ) {
 665                 $this->mId = $id;
 666         }
 667
 668         /**
 669          * Get text row ID
 670          *
 671          * @return Integer|null
 672          */
 673         public function getTextId() {
 674                 return $this->mTextId;
 675         }
 676
 677         /**
 678          * Get parent revision ID (the original previous page revision)
 679          *
 680          * @return Integer|null
 681          */
 682         public function getParentId() {
 683                 return $this->mParentId;
 684         }
 685
 686         /**
 687          * Returns the length of the text in this revision, or null if unknown.
 688          *
 689          * @return Integer|null
 690          */
 691         public function getSize() {
 692                 return $this->mSize;
 693         }
 694
 695         /**
 696          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 697          *
 698          * @return String|null
 699          */
 700         public function getSha1() {
 701                 return $this->mSha1;
 702         }
 703
 704         /**
 705          * Returns the title of the page associated with this entry or null.
 706          *
 707          * Will do a query, when title is not set and id is given.
 708          *
 709          * @return Title|null
 710          */
 711         public function getTitle() {
 712                 if( isset( $this->mTitle ) ) {
 713                         return $this->mTitle;
 714                 }
 715                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 716                         $dbr = wfGetDB( DB_SLAVE );
 717                         $row = $dbr->selectRow(
 718                                 array( 'page', 'revision' ),
 719                                 self::selectPageFields(),
 720                                 array( 'page_id=rev_page',
 721                                            'rev_id' => $this->mId ),
 722                                 __METHOD__ );
 723                         if ( $row ) {
 724                                 $this->mTitle = Title::newFromRow( $row );
 725                         }
 726                 }
 727
 728                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 729                         $this->mTitle = Title::newFromID( $this->mPage );
 730                 }
 731
 732                 return $this->mTitle;
 733         }
 734
 735         /**
 736          * Set the title of the revision
 737          *
 738          * @param $title Title
 739          */
 740         public function setTitle( $title ) {
 741                 $this->mTitle = $title;
 742         }
 743
 744         /**
 745          * Get the page ID
 746          *
 747          * @return Integer|null
 748          */
 749         public function getPage() {
 750                 return $this->mPage;
 751         }
 752
 753         /**
 754          * Fetch revision's user id if it's available to the specified audience.
 755          * If the specified audience does not have access to it, zero will be
 756          * returned.
 757          *
 758          * @param $audience Integer: one of:
 759          *      Revision::FOR_PUBLIC       to be displayed to all users
 760          *      Revision::FOR_THIS_USER    to be displayed to the given user
 761          *      Revision::RAW              get the ID regardless of permissions
 762          * @param $user User object to check for, only if FOR_THIS_USER is passed
 763          *              to the $audience parameter
 764          * @return Integer
 765          */
 766         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 767                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 768                         return 0;
 769                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 770                         return 0;
 771                 } else {
 772                         return $this->mUser;
 773                 }
 774         }
 775
 776         /**
 777          * Fetch revision's user id without regard for the current user's permissions
 778          *
 779          * @return String
 780          */
 781         public function getRawUser() {
 782                 return $this->mUser;
 783         }
 784
 785         /**
 786          * Fetch revision's username if it's available to the specified audience.
 787          * If the specified audience does not have access to the username, an
 788          * empty string will be returned.
 789          *
 790          * @param $audience Integer: one of:
 791          *      Revision::FOR_PUBLIC       to be displayed to all users
 792          *      Revision::FOR_THIS_USER    to be displayed to the given user
 793          *      Revision::RAW              get the text regardless of permissions
 794          * @param $user User object to check for, only if FOR_THIS_USER is passed
 795          *              to the $audience parameter
 796          * @return string
 797          */
 798         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 799                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 800                         return '';
 801                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 802                         return '';
 803                 } else {
 804                         return $this->getRawUserText();
 805                 }
 806         }
 807
 808         /**
 809          * Fetch revision's username without regard for view restrictions
 810          *
 811          * @return String
 812          */
 813         public function getRawUserText() {
 814                 if ( $this->mUserText === null ) {
 815                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 816                         if ( $this->mUserText === false ) {
 817                                 # This shouldn't happen, but it can if the wiki was recovered
 818                                 # via importing revs and there is no user table entry yet.
 819                                 $this->mUserText = $this->mOrigUserText;
 820                         }
 821                 }
 822                 return $this->mUserText;
 823         }
 824
 825         /**
 826          * Fetch revision comment if it's available to the specified audience.
 827          * If the specified audience does not have access to the comment, an
 828          * empty string will be returned.
 829          *
 830          * @param $audience Integer: one of:
 831          *      Revision::FOR_PUBLIC       to be displayed to all users
 832          *      Revision::FOR_THIS_USER    to be displayed to the given user
 833          *      Revision::RAW              get the text regardless of permissions
 834          * @param $user User object to check for, only if FOR_THIS_USER is passed
 835          *              to the $audience parameter
 836          * @return String
 837          */
 838         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 839                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 840                         return '';
 841                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 842                         return '';
 843                 } else {
 844                         return $this->mComment;
 845                 }
 846         }
 847
 848         /**
 849          * Fetch revision comment without regard for the current user's permissions
 850          *
 851          * @return String
 852          */
 853         public function getRawComment() {
 854                 return $this->mComment;
 855         }
 856
 857         /**
 858          * @return Boolean
 859          */
 860         public function isMinor() {
 861                 return (bool)$this->mMinorEdit;
 862         }
 863
 864         /**
 865          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 866          */
 867         public function isUnpatrolled() {
 868                 if( $this->mUnpatrolled !== null ) {
 869                         return $this->mUnpatrolled;
 870                 }
 871                 $dbr = wfGetDB( DB_SLAVE );
 872                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 873                         'rc_id',
 874                         array( // Add redundant user,timestamp condition so we can use the existing index
 875                                 'rc_user_text'  => $this->getRawUserText(),
 876                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 877                                 'rc_this_oldid' => $this->getId(),
 878                                 'rc_patrolled'  => 0
 879                         ),
 880                         __METHOD__
 881                 );
 882                 return (int)$this->mUnpatrolled;
 883         }
 884
 885         /**
 886          * @param $field int one of DELETED_* bitfield constants
 887          *
 888          * @return Boolean
 889          */
 890         public function isDeleted( $field ) {
 891                 return ( $this->mDeleted & $field ) == $field;
 892         }
 893
 894         /**
 895          * Get the deletion bitfield of the revision
 896          *
 897          * @return int
 898          */
 899         public function getVisibility() {
 900                 return (int)$this->mDeleted;
 901         }
 902
 903         /**
 904          * Fetch revision text if it's available to the specified audience.
 905          * If the specified audience does not have the ability to view this
 906          * revision, an empty string will be returned.
 907          *
 908          * @param $audience Integer: one of:
 909          *      Revision::FOR_PUBLIC       to be displayed to all users
 910          *      Revision::FOR_THIS_USER    to be displayed to the given user
 911          *      Revision::RAW              get the text regardless of permissions
 912          * @param $user User object to check for, only if FOR_THIS_USER is passed
 913          *              to the $audience parameter
 914          *
 915          * @deprecated in 1.21, use getContent() instead
 916          * @todo: replace usage in core
 917          * @return String
 918          */
 919         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 920                 ContentHandler::deprecated( __METHOD__, '1.21' );
 921
 922                 $content = $this->getContent( $audience, $user );
 923                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 924         }
 925
 926         /**
 927          * Fetch revision content if it's available to the specified audience.
 928          * If the specified audience does not have the ability to view this
 929          * revision, null will be returned.
 930          *
 931          * @param $audience Integer: one of:
 932          *      Revision::FOR_PUBLIC       to be displayed to all users
 933          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 934          *      Revision::RAW              get the text regardless of permissions
 935          * @param $user User object to check for, only if FOR_THIS_USER is passed
 936          *              to the $audience parameter
 937          * @since 1.21
 938          * @return Content|null
 939          */
 940         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 941                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 942                         return null;
 943                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 944                         return null;
 945                 } else {
 946                         return $this->getContentInternal();
 947                 }
 948         }
 949
 950         /**
 951          * Alias for getText(Revision::FOR_THIS_USER)
 952          *
 953          * @deprecated since 1.17
 954          * @return String
 955          */
 956         public function revText() {
 957                 wfDeprecated( __METHOD__, '1.17' );
 958                 return $this->getText( self::FOR_THIS_USER );
 959         }
 960
 961         /**
 962          * Fetch revision text without regard for view restrictions
 963          *
 964          * @return String
 965          *
 966          * @deprecated since 1.21. Instead, use Revision::getContent( Revision::RAW )
 967          *                         or Revision::getSerializedData() as appropriate.
 968          */
 969         public function getRawText() {
 970                 ContentHandler::deprecated( __METHOD__, "1.21" );
 971                 return $this->getText( self::RAW );
 972         }
 973
 974         /**
 975          * Fetch original serialized data without regard for view restrictions
 976          *
 977          * @since 1.21
 978          * @return String
 979          */
 980         public function getSerializedData() {
 981                 return $this->mText;
 982         }
 983
 984         /**
 985          * Gets the content object for the revision (or null on failure).
 986          *
 987          * Note that for mutable Content objects, each call to this method will return a
 988          * fresh clone.
 989          *
 990          * @since 1.21
 991          * @return Content|null the Revision's content, or null on failure.
 992          */
 993         protected function getContentInternal() {
 994                 if( is_null( $this->mContent ) ) {
 995                         // Revision is immutable. Load on demand:
 996                         if( is_null( $this->mText ) ) {
 997                                 $this->mText = $this->loadText();
 998                         }
 999
1000                         if ( $this->mText !== null && $this->mText !== false ) {
1001                                 // Unserialize content
1002                                 $handler = $this->getContentHandler();
1003                                 $format = $this->getContentFormat();
1004
1005                                 $this->mContent = $handler->unserializeContent( $this->mText, $format );
1006                         } else {
1007                                 $this->mContent = false; // negative caching!
1008                         }
1009                 }
1010
1011                 // NOTE: copy() will return $this for immutable content objects
1012                 return $this->mContent ? $this->mContent->copy() : null;
1013         }
1014
1015         /**
1016          * Returns the content model for this revision.
1017          *
1018          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
1019          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1020          * is used as a last resort.
1021          *
1022          * @return String the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
1023          **/
1024         public function getContentModel() {
1025                 if ( !$this->mContentModel ) {
1026                         $title = $this->getTitle();
1027                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
1028
1029                         assert( !empty( $this->mContentModel ) );
1030                 }
1031
1032                 return $this->mContentModel;
1033         }
1034
1035         /**
1036          * Returns the content format for this revision.
1037          *
1038          * If no content format was stored in the database, the default format for this
1039          * revision's content model is returned.
1040          *
1041          * @return String the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
1042          **/
1043         public function getContentFormat() {
1044                 if ( !$this->mContentFormat ) {
1045                         $handler = $this->getContentHandler();
1046                         $this->mContentFormat = $handler->getDefaultFormat();
1047
1048                         assert( !empty( $this->mContentFormat ) );
1049                 }
1050
1051                 return $this->mContentFormat;
1052         }
1053
1054         /**
1055          * Returns the content handler appropriate for this revision's content model.
1056          *
1057          * @throws MWException
1058          * @return ContentHandler
1059          */
1060         public function getContentHandler() {
1061                 if ( !$this->mContentHandler ) {
1062                         $model = $this->getContentModel();
1063                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1064
1065                         $format = $this->getContentFormat();
1066
1067                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1068                                 throw new MWException( "Oops, the content format $format is not supported for this content model, $model" );
1069                         }
1070                 }
1071
1072                 return $this->mContentHandler;
1073         }
1074
1075         /**
1076          * @return String
1077          */
1078         public function getTimestamp() {
1079                 return wfTimestamp( TS_MW, $this->mTimestamp );
1080         }
1081
1082         /**
1083          * @return Boolean
1084          */
1085         public function isCurrent() {
1086                 return $this->mCurrent;
1087         }
1088
1089         /**
1090          * Get previous revision for this title
1091          *
1092          * @return Revision or null
1093          */
1094         public function getPrevious() {
1095                 if( $this->getTitle() ) {
1096                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1097                         if( $prev ) {
1098                                 return self::newFromTitle( $this->getTitle(), $prev );
1099                         }
1100                 }
1101                 return null;
1102         }
1103
1104         /**
1105          * Get next revision for this title
1106          *
1107          * @return Revision or null
1108          */
1109         public function getNext() {
1110                 if( $this->getTitle() ) {
1111                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1112                         if ( $next ) {
1113                                 return self::newFromTitle( $this->getTitle(), $next );
1114                         }
1115                 }
1116                 return null;
1117         }
1118
1119         /**
1120          * Get previous revision Id for this page_id
1121          * This is used to populate rev_parent_id on save
1122          *
1123          * @param $db DatabaseBase
1124          * @return Integer
1125          */
1126         private function getPreviousRevisionId( $db ) {
1127                 if( is_null( $this->mPage ) ) {
1128                         return 0;
1129                 }
1130                 # Use page_latest if ID is not given
1131                 if( !$this->mId ) {
1132                         $prevId = $db->selectField( 'page', 'page_latest',
1133                                 array( 'page_id' => $this->mPage ),
1134                                 __METHOD__ );
1135                 } else {
1136                         $prevId = $db->selectField( 'revision', 'rev_id',
1137                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1138                                 __METHOD__,
1139                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1140                 }
1141                 return intval( $prevId );
1142         }
1143
1144         /**
1145           * Get revision text associated with an old or archive row
1146           * $row is usually an object from wfFetchRow(), both the flags and the text
1147           * field must be included
1148           *
1149           * @param $row Object: the text data
1150           * @param $prefix String: table prefix (default 'old_')
1151           * @return String: text the text requested or false on failure
1152           */
1153         public static function getRevisionText( $row, $prefix = 'old_' ) {
1154                 wfProfileIn( __METHOD__ );
1155
1156                 # Get data
1157                 $textField = $prefix . 'text';
1158                 $flagsField = $prefix . 'flags';
1159
1160                 if( isset( $row->$flagsField ) ) {
1161                         $flags = explode( ',', $row->$flagsField );
1162                 } else {
1163                         $flags = array();
1164                 }
1165
1166                 if( isset( $row->$textField ) ) {
1167                         $text = $row->$textField;
1168                 } else {
1169                         wfProfileOut( __METHOD__ );
1170                         return false;
1171                 }
1172
1173                 # Use external methods for external objects, text in table is URL-only then
1174                 if ( in_array( 'external', $flags ) ) {
1175                         $url = $text;
1176                         $parts = explode( '://', $url, 2 );
1177                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1178                                 wfProfileOut( __METHOD__ );
1179                                 return false;
1180                         }
1181                         $text = ExternalStore::fetchFromURL( $url );
1182                 }
1183
1184                 // If the text was fetched without an error, convert it
1185                 if ( $text !== false ) {
1186                         if( in_array( 'gzip', $flags ) ) {
1187                                 # Deal with optional compression of archived pages.
1188                                 # This can be done periodically via maintenance/compressOld.php, and
1189                                 # as pages are saved if $wgCompressRevisions is set.
1190                                 $text = gzinflate( $text );
1191                         }
1192
1193                         if( in_array( 'object', $flags ) ) {
1194                                 # Generic compressed storage
1195                                 $obj = unserialize( $text );
1196                                 if ( !is_object( $obj ) ) {
1197                                         // Invalid object
1198                                         wfProfileOut( __METHOD__ );
1199                                         return false;
1200                                 }
1201                                 $text = $obj->getText();
1202                         }
1203
1204                         global $wgLegacyEncoding;
1205                         if( $text !== false && $wgLegacyEncoding
1206                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1207                         {
1208                                 # Old revisions kept around in a legacy encoding?
1209                                 # Upconvert on demand.
1210                                 # ("utf8" checked for compatibility with some broken
1211                                 #  conversion scripts 2008-12-30)
1212                                 global $wgContLang;
1213                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1214                         }
1215                 }
1216                 wfProfileOut( __METHOD__ );
1217                 return $text;
1218         }
1219
1220         /**
1221          * If $wgCompressRevisions is enabled, we will compress data.
1222          * The input string is modified in place.
1223          * Return value is the flags field: contains 'gzip' if the
1224          * data is compressed, and 'utf-8' if we're saving in UTF-8
1225          * mode.
1226          *
1227          * @param $text Mixed: reference to a text
1228          * @return String
1229          */
1230         public static function compressRevisionText( &$text ) {
1231                 global $wgCompressRevisions;
1232                 $flags = array();
1233
1234                 # Revisions not marked this way will be converted
1235                 # on load if $wgLegacyCharset is set in the future.
1236                 $flags[] = 'utf-8';
1237
1238                 if( $wgCompressRevisions ) {
1239                         if( function_exists( 'gzdeflate' ) ) {
1240                                 $text = gzdeflate( $text );
1241                                 $flags[] = 'gzip';
1242                         } else {
1243                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1244                         }
1245                 }
1246                 return implode( ',', $flags );
1247         }
1248
1249         /**
1250          * Insert a new revision into the database, returning the new revision ID
1251          * number on success and dies horribly on failure.
1252          *
1253          * @param $dbw DatabaseBase: (master connection)
1254          * @throws MWException
1255          * @return Integer
1256          */
1257         public function insertOn( $dbw ) {
1258                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1259
1260                 wfProfileIn( __METHOD__ );
1261
1262                 $this->checkContentModel();
1263
1264                 $data = $this->mText;
1265                 $flags = self::compressRevisionText( $data );
1266
1267                 # Write to external storage if required
1268                 if( $wgDefaultExternalStore ) {
1269                         // Store and get the URL
1270                         $data = ExternalStore::insertToDefault( $data );
1271                         if( !$data ) {
1272                                 throw new MWException( "Unable to store text to external storage" );
1273                         }
1274                         if( $flags ) {
1275                                 $flags .= ',';
1276                         }
1277                         $flags .= 'external';
1278                 }
1279
1280                 # Record the text (or external storage URL) to the text table
1281                 if( !isset( $this->mTextId ) ) {
1282                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1283                         $dbw->insert( 'text',
1284                                 array(
1285                                         'old_id'    => $old_id,
1286                                         'old_text'  => $data,
1287                                         'old_flags' => $flags,
1288                                 ), __METHOD__
1289                         );
1290                         $this->mTextId = $dbw->insertId();
1291                 }
1292
1293                 if ( $this->mComment === null ) $this->mComment = "";
1294
1295                 # Record the edit in revisions
1296                 $rev_id = isset( $this->mId )
1297                         ? $this->mId
1298                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1299                 $row = array(
1300                         'rev_id'         => $rev_id,
1301                         'rev_page'       => $this->mPage,
1302                         'rev_text_id'    => $this->mTextId,
1303                         'rev_comment'    => $this->mComment,
1304                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1305                         'rev_user'       => $this->mUser,
1306                         'rev_user_text'  => $this->mUserText,
1307                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1308                         'rev_deleted'    => $this->mDeleted,
1309                         'rev_len'        => $this->mSize,
1310                         'rev_parent_id'  => is_null( $this->mParentId )
1311                                 ? $this->getPreviousRevisionId( $dbw )
1312                                 : $this->mParentId,
1313                         'rev_sha1'       => is_null( $this->mSha1 )
1314                                 ? Revision::base36Sha1( $this->mText )
1315                                 : $this->mSha1,
1316                 );
1317
1318                 if ( $wgContentHandlerUseDB ) {
1319                         //NOTE: Store null for the default model and format, to save space.
1320                         //XXX: Makes the DB sensitive to changed defaults. Make this behaviour optional? Only in miser mode?
1321
1322                         $model = $this->getContentModel();
1323                         $format = $this->getContentFormat();
1324
1325                         $title = $this->getTitle();
1326
1327                         if ( $title === null ) {
1328                                 throw new MWException( "Insufficient information to determine the title of the revision's page!" );
1329                         }
1330
1331                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1332                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1333
1334                         $row[ 'rev_content_model' ] = ( $model === $defaultModel ) ? null : $model;
1335                         $row[ 'rev_content_format' ] = ( $format === $defaultFormat ) ? null : $format;
1336                 }
1337
1338                 $dbw->insert( 'revision', $row, __METHOD__ );
1339
1340                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1341
1342                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1343
1344                 wfProfileOut( __METHOD__ );
1345                 return $this->mId;
1346         }
1347
1348         protected function checkContentModel() {
1349                 global $wgContentHandlerUseDB;
1350
1351                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1352
1353                 $model = $this->getContentModel();
1354                 $format = $this->getContentFormat();
1355                 $handler = $this->getContentHandler();
1356
1357                 if ( !$handler->isSupportedFormat( $format ) ) {
1358                         $t = $title->getPrefixedDBkey();
1359
1360                         throw new MWException( "Can't use format $format with content model $model on $t" );
1361                 }
1362
1363                 if ( !$wgContentHandlerUseDB && $title ) {
1364                         // if $wgContentHandlerUseDB is not set, all revisions must use the default content model and format.
1365
1366                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1367                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1368                         $defaultFormat = $defaultHandler->getDefaultFormat();
1369
1370                         if ( $this->getContentModel() != $defaultModel ) {
1371                                 $t = $title->getPrefixedDBkey();
1372
1373                                 throw new MWException( "Can't save non-default content model with \$wgContentHandlerUseDB disabled: "
1374                                                                                 . "model is $model , default for $t is $defaultModel" );
1375                         }
1376
1377                         if ( $this->getContentFormat() != $defaultFormat ) {
1378                                 $t = $title->getPrefixedDBkey();
1379
1380                                 throw new MWException( "Can't use non-default content format with \$wgContentHandlerUseDB disabled: "
1381                                                                                 . "format is $format, default for $t is $defaultFormat" );
1382                         }
1383                 }
1384
1385                 $content = $this->getContent( Revision::RAW );
1386
1387                 if ( !$content || !$content->isValid() ) {
1388                         $t = $title->getPrefixedDBkey();
1389
1390                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1391                 }
1392         }
1393
1394         /**
1395          * Get the base 36 SHA-1 value for a string of text
1396          * @param $text String
1397          * @return String
1398          */
1399         public static function base36Sha1( $text ) {
1400                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1401         }
1402
1403         /**
1404          * Lazy-load the revision's text.
1405          * Currently hardcoded to the 'text' table storage engine.
1406          *
1407          * @return String|bool the revision's text, or false on failure
1408          */
1409         protected function loadText() {
1410                 wfProfileIn( __METHOD__ );
1411
1412                 // Caching may be beneficial for massive use of external storage
1413                 global $wgRevisionCacheExpiry, $wgMemc;
1414                 $textId = $this->getTextId();
1415                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1416                 if( $wgRevisionCacheExpiry ) {
1417                         $text = $wgMemc->get( $key );
1418                         if( is_string( $text ) ) {
1419                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1420                                 wfProfileOut( __METHOD__ );
1421                                 return $text;
1422                         }
1423                 }
1424
1425                 // If we kept data for lazy extraction, use it now...
1426                 if ( isset( $this->mTextRow ) ) {
1427                         $row = $this->mTextRow;
1428                         $this->mTextRow = null;
1429                 } else {
1430                         $row = null;
1431                 }
1432
1433                 if( !$row ) {
1434                         // Text data is immutable; check slaves first.
1435                         $dbr = wfGetDB( DB_SLAVE );
1436                         $row = $dbr->selectRow( 'text',
1437                                 array( 'old_text', 'old_flags' ),
1438                                 array( 'old_id' => $this->getTextId() ),
1439                                 __METHOD__ );
1440                 }
1441
1442                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1443                         // Possible slave lag!
1444                         $dbw = wfGetDB( DB_MASTER );
1445                         $row = $dbw->selectRow( 'text',
1446                                 array( 'old_text', 'old_flags' ),
1447                                 array( 'old_id' => $this->getTextId() ),
1448                                 __METHOD__ );
1449                 }
1450
1451                 $text = self::getRevisionText( $row );
1452
1453                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1454                 if( $wgRevisionCacheExpiry && $text !== false ) {
1455                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1456                 }
1457
1458                 wfProfileOut( __METHOD__ );
1459
1460                 return $text;
1461         }
1462
1463         /**
1464          * Create a new null-revision for insertion into a page's
1465          * history. This will not re-save the text, but simply refer
1466          * to the text from the previous version.
1467          *
1468          * Such revisions can for instance identify page rename
1469          * operations and other such meta-modifications.
1470          *
1471          * @param $dbw DatabaseBase
1472          * @param $pageId Integer: ID number of the page to read from
1473          * @param $summary String: revision's summary
1474          * @param $minor Boolean: whether the revision should be considered as minor
1475          * @return Revision|null on error
1476          */
1477         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1478                 global $wgContentHandlerUseDB;
1479
1480                 wfProfileIn( __METHOD__ );
1481
1482                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1483                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1484
1485                 if ( $wgContentHandlerUseDB ) {
1486                         $fields[] = 'rev_content_model';
1487                         $fields[] = 'rev_content_format';
1488                 }
1489
1490                 $current = $dbw->selectRow(
1491                         array( 'page', 'revision' ),
1492                         $fields,
1493                         array(
1494                                 'page_id' => $pageId,
1495                                 'page_latest=rev_id',
1496                                 ),
1497                         __METHOD__ );
1498
1499                 if( $current ) {
1500                         $row = array(
1501                                 'page'       => $pageId,
1502                                 'comment'    => $summary,
1503                                 'minor_edit' => $minor,
1504                                 'text_id'    => $current->rev_text_id,
1505                                 'parent_id'  => $current->page_latest,
1506                                 'len'        => $current->rev_len,
1507                                 'sha1'       => $current->rev_sha1
1508                         );
1509
1510                         if ( $wgContentHandlerUseDB ) {
1511                                 $row[ 'content_model' ] = $current->rev_content_model;
1512                                 $row[ 'content_format' ] = $current->rev_content_format;
1513                         }
1514
1515                         $revision = new Revision( $row );
1516                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1517                 } else {
1518                         $revision = null;
1519                 }
1520
1521                 wfProfileOut( __METHOD__ );
1522                 return $revision;
1523         }
1524
1525         /**
1526          * Determine if the current user is allowed to view a particular
1527          * field of this revision, if it's marked as deleted.
1528          *
1529          * @param $field Integer:one of self::DELETED_TEXT,
1530          *                              self::DELETED_COMMENT,
1531          *                              self::DELETED_USER
1532          * @param $user User object to check, or null to use $wgUser
1533          * @return Boolean
1534          */
1535         public function userCan( $field, User $user = null ) {
1536                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1537         }
1538
1539         /**
1540          * Determine if the current user is allowed to view a particular
1541          * field of this revision, if it's marked as deleted. This is used
1542          * by various classes to avoid duplication.
1543          *
1544          * @param $bitfield Integer: current field
1545          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1546          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1547          *                               self::DELETED_USER = File::DELETED_USER
1548          * @param $user User object to check, or null to use $wgUser
1549          * @return Boolean
1550          */
1551         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1552                 if( $bitfield & $field ) { // aspect is deleted
1553                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1554                                 $permission = 'suppressrevision';
1555                         } elseif ( $field & self::DELETED_TEXT ) {
1556                                 $permission = 'deletedtext';
1557                         } else {
1558                                 $permission = 'deletedhistory';
1559                         }
1560                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1561                         if ( $user === null ) {
1562                                 global $wgUser;
1563                                 $user = $wgUser;
1564                         }
1565                         return $user->isAllowed( $permission );
1566                 } else {
1567                         return true;
1568                 }
1569         }
1570
1571         /**
1572          * Get rev_timestamp from rev_id, without loading the rest of the row
1573          *
1574          * @param $title Title
1575          * @param $id Integer
1576          * @return String
1577          */
1578         static function getTimestampFromId( $title, $id ) {
1579                 $dbr = wfGetDB( DB_SLAVE );
1580                 // Casting fix for DB2
1581                 if ( $id == '' ) {
1582                         $id = 0;
1583                 }
1584                 $conds = array( 'rev_id' => $id );
1585                 $conds['rev_page'] = $title->getArticleID();
1586                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1587                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1588                         # Not in slave, try master
1589                         $dbw = wfGetDB( DB_MASTER );
1590                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1591                 }
1592                 return wfTimestamp( TS_MW, $timestamp );
1593         }
1594
1595         /**
1596          * Get count of revisions per page...not very efficient
1597          *
1598          * @param $db DatabaseBase
1599          * @param $id Integer: page id
1600          * @return Integer
1601          */
1602         static function countByPageId( $db, $id ) {
1603                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1604                         array( 'rev_page' => $id ), __METHOD__ );
1605                 if( $row ) {
1606                         return $row->revCount;
1607                 }
1608                 return 0;
1609         }
1610
1611         /**
1612          * Get count of revisions per page...not very efficient
1613          *
1614          * @param $db DatabaseBase
1615          * @param $title Title
1616          * @return Integer
1617          */
1618         static function countByTitle( $db, $title ) {
1619                 $id = $title->getArticleID();
1620                 if( $id ) {
1621                         return self::countByPageId( $db, $id );
1622                 }
1623                 return 0;
1624         }
1625
1626         /**
1627          * Check if no edits were made by other users since
1628          * the time a user started editing the page. Limit to
1629          * 50 revisions for the sake of performance.
1630          *
1631          * @since 1.20
1632          *
1633          * @param DatabaseBase|int $db the Database to perform the check on. May be given as a Database object or
1634          *        a database identifier usable with wfGetDB.
1635          * @param int $pageId the ID of the page in question
1636          * @param int $userId the ID of the user in question
1637          * @param string $since look at edits since this time
1638          *
1639          * @return bool True if the given user was the only one to edit since the given timestamp
1640          */
1641         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1642                 if ( !$userId ) return false;
1643
1644                 if ( is_int( $db ) ) {
1645                         $db = wfGetDB( $db );
1646                 }
1647
1648                 $res = $db->select( 'revision',
1649                         'rev_user',
1650                         array(
1651                                 'rev_page' => $pageId,
1652                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1653                         ),
1654                         __METHOD__,
1655                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1656                 foreach ( $res as $row ) {
1657                         if ( $row->rev_user != $userId ) {
1658                                 return false;
1659                         }
1660                 }
1661                 return true;
1662         }
1663 }