includes/Revision.php

   1 <?php
   2 /**
   3  * @package MediaWiki
   4  * @todo document
   5  */
   6
   7 /** */
   8 require_once( 'Database.php' );
   9
  10 /**
  11  * @package MediaWiki
  12  * @todo document
  13  */
  14 class Revision {
  15         const DELETED_TEXT      = 1;
  16         const DELETED_COMMENT   = 2;
  17         const DELETED_USER      = 4;
  18         const DELETED_RESTRICTED = 8;
  19
  20         /**
  21          * Load a page revision from a given revision ID number.
  22          * Returns null if no such revision can be found.
  23          *
  24          * @param int $id
  25          * @static
  26          * @access public
  27          */
  28         public static function newFromId( $id ) {
  29                 return Revision::newFromConds(
  30                         array( 'page_id=rev_page',
  31                                'rev_id' => intval( $id ) ) );
  32         }
  33
  34         /**
  35          * Load either the current, or a specified, revision
  36          * that's attached to a given title. If not attached
  37          * to that title, will return null.
  38          *
  39          * @param Title $title
  40          * @param int $id
  41          * @return Revision
  42          * @access public
  43          * @static
  44          */
  45         public static function newFromTitle( &$title, $id = 0 ) {
  46                 if( $id ) {
  47                         $matchId = intval( $id );
  48                 } else {
  49                         $matchId = 'page_latest';
  50                 }
  51                 return Revision::newFromConds(
  52                         array( "rev_id=$matchId",
  53                                'page_id=rev_page',
  54                                'page_namespace' => $title->getNamespace(),
  55                                'page_title'     => $title->getDbkey() ) );
  56         }
  57
  58         /**
  59          * Load either the current, or a specified, revision
  60          * that's attached to a given page. If not attached
  61          * to that page, will return null.
  62          *
  63          * @param Database $db
  64          * @param int $pageid
  65          * @param int $id
  66          * @return Revision
  67          * @access public
  68          */
  69         public static function loadFromPageId( &$db, $pageid, $id = 0 ) {
  70                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  71                 if( $id ) {
  72                         $conds['rev_id']=intval($id);
  73                 } else {
  74                         $conds[]='rev_id=page_latest';
  75                 }
  76                 return Revision::loadFromConds( $db, $conds );
  77         }
  78
  79         /**
  80          * Load either the current, or a specified, revision
  81          * that's attached to a given page. If not attached
  82          * to that page, will return null.
  83          *
  84          * @param Database $db
  85          * @param Title $title
  86          * @param int $id
  87          * @return Revision
  88          * @access public
  89          */
  90         function loadFromTitle( &$db, $title, $id = 0 ) {
  91                 if( $id ) {
  92                         $matchId = intval( $id );
  93                 } else {
  94                         $matchId = 'page_latest';
  95                 }
  96                 return Revision::loadFromConds(
  97                         $db,
  98                         array( "rev_id=$matchId",
  99                                'page_id=rev_page',
 100                                'page_namespace' => $title->getNamespace(),
 101                                'page_title'     => $title->getDbkey() ) );
 102         }
 103
 104         /**
 105          * Load the revision for the given title with the given timestamp.
 106          * WARNING: Timestamps may in some circumstances not be unique,
 107          * so this isn't the best key to use.
 108          *
 109          * @param Database $db
 110          * @param Title $title
 111          * @param string $timestamp
 112          * @return Revision
 113          * @access public
 114          * @static
 115          */
 116         function loadFromTimestamp( &$db, &$title, $timestamp ) {
 117                 return Revision::loadFromConds(
 118                         $db,
 119                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 120                                'page_id=rev_page',
 121                                'page_namespace' => $title->getNamespace(),
 122                                'page_title'     => $title->getDbkey() ) );
 123         }
 124
 125         /**
 126          * Given a set of conditions, fetch a revision.
 127          *
 128          * @param array $conditions
 129          * @return Revision
 130          * @static
 131          * @access private
 132          */
 133         private static function newFromConds( $conditions ) {
 134                 $db =& wfGetDB( DB_SLAVE );
 135                 $row = Revision::loadFromConds( $db, $conditions );
 136                 if( is_null( $row ) ) {
 137                         $dbw =& wfGetDB( DB_MASTER );
 138                         $row = Revision::loadFromConds( $dbw, $conditions );
 139                 }
 140                 return $row;
 141         }
 142
 143         /**
 144          * Given a set of conditions, fetch a revision from
 145          * the given database connection.
 146          *
 147          * @param Database $db
 148          * @param array $conditions
 149          * @return Revision
 150          * @static
 151          * @access private
 152          */
 153         private static function loadFromConds( &$db, $conditions ) {
 154                 $res = Revision::fetchFromConds( $db, $conditions );
 155                 if( $res ) {
 156                         $row = $res->fetchObject();
 157                         $res->free();
 158                         if( $row ) {
 159                                 $ret = new Revision( $row );
 160                                 return $ret;
 161                         }
 162                 }
 163                 $ret = null;
 164                 return $ret;
 165         }
 166
 167         /**
 168          * Return a wrapper for a series of database rows to
 169          * fetch all of a given page's revisions in turn.
 170          * Each row can be fed to the constructor to get objects.
 171          *
 172          * @param Title $title
 173          * @return ResultWrapper
 174          * @static
 175          * @access public
 176          */
 177         function fetchAllRevisions( &$title ) {
 178                 return Revision::fetchFromConds(
 179                         wfGetDB( DB_SLAVE ),
 180                         array( 'page_namespace' => $title->getNamespace(),
 181                                'page_title'     => $title->getDbkey(),
 182                                'page_id=rev_page' ) );
 183         }
 184
 185         /**
 186          * Return a wrapper for a series of database rows to
 187          * fetch all of a given page's revisions in turn.
 188          * Each row can be fed to the constructor to get objects.
 189          *
 190          * @param Title $title
 191          * @return ResultWrapper
 192          * @static
 193          * @access public
 194          */
 195         public static function fetchRevision( &$title ) {
 196                 return Revision::fetchFromConds(
 197                         wfGetDB( DB_SLAVE ),
 198                         array( 'rev_id=page_latest',
 199                                'page_namespace' => $title->getNamespace(),
 200                                'page_title'     => $title->getDbkey(),
 201                                'page_id=rev_page' ) );
 202         }
 203
 204         /**
 205          * Given a set of conditions, return a ResultWrapper
 206          * which will return matching database rows with the
 207          * fields necessary to build Revision objects.
 208          *
 209          * @param Database $db
 210          * @param array $conditions
 211          * @return ResultWrapper
 212          * @static
 213          * @access private
 214          */
 215         private static function fetchFromConds( &$db, $conditions ) {
 216                 $res = $db->select(
 217                         array( 'page', 'revision' ),
 218                         array( 'page_namespace',
 219                                'page_title',
 220                                'page_latest',
 221                                'rev_id',
 222                                'rev_page',
 223                                'rev_text_id',
 224                                'rev_comment',
 225                                'rev_user_text',
 226                                'rev_user',
 227                                'rev_minor_edit',
 228                                'rev_timestamp',
 229                                'rev_deleted' ),
 230                         $conditions,
 231                         'Revision::fetchRow',
 232                         array( 'LIMIT' => 1 ) );
 233                 $ret = $db->resultObject( $res );
 234                 return $ret;
 235         }
 236
 237         /**
 238          * @param object $row
 239          * @access private
 240          */
 241         function Revision( $row ) {
 242                 if( is_object( $row ) ) {
 243                         $this->mId        = intval( $row->rev_id );
 244                         $this->mPage      = intval( $row->rev_page );
 245                         $this->mTextId    = intval( $row->rev_text_id );
 246                         $this->mComment   =         $row->rev_comment;
 247                         $this->mUserText  =         $row->rev_user_text;
 248                         $this->mUser      = intval( $row->rev_user );
 249                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 250                         $this->mTimestamp =         $row->rev_timestamp;
 251                         $this->mDeleted   = intval( $row->rev_deleted );
 252
 253                         if( isset( $row->page_latest ) ) {
 254                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 255                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 256                                                                       $row->page_title );
 257                         } else {
 258                                 $this->mCurrent = false;
 259                                 $this->mTitle = null;
 260                         }
 261
 262                         // Lazy extraction...
 263                         $this->mText      = null;
 264                         if( isset( $row->old_text ) ) {
 265                                 $this->mTextRow = $row;
 266                         } else {
 267                                 // 'text' table row entry will be lazy-loaded
 268                                 $this->mTextRow = null;
 269                         }
 270                 } elseif( is_array( $row ) ) {
 271                         // Build a new revision to be saved...
 272                         global $wgUser;
 273
 274                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 275                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 276                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 277                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 278                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 279                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 280                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 281                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 282
 283                         // Enforce spacing trimming on supplied text
 284                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 285                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 286
 287                         $this->mTitle     = null; # Load on demand if needed
 288                         $this->mCurrent   = false;
 289                 } else {
 290                         throw new MWException( 'Revision constructor passed invalid row format.' );
 291                 }
 292         }
 293
 294         /**#@+
 295          * @access public
 296          */
 297
 298         /**
 299          * @return int
 300          */
 301         function getId() {
 302                 return $this->mId;
 303         }
 304
 305         /**
 306          * @return int
 307          */
 308         function getTextId() {
 309                 return $this->mTextId;
 310         }
 311
 312         /**
 313          * Returns the title of the page associated with this entry.
 314          * @return Title
 315          */
 316         function getTitle() {
 317                 if( isset( $this->mTitle ) ) {
 318                         return $this->mTitle;
 319                 }
 320                 $dbr =& wfGetDB( DB_SLAVE );
 321                 $row = $dbr->selectRow(
 322                         array( 'page', 'revision' ),
 323                         array( 'page_namespace', 'page_title' ),
 324                         array( 'page_id=rev_page',
 325                                'rev_id' => $this->mId ),
 326                         'Revision::getTitle' );
 327                 if( $row ) {
 328                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 329                                                            $row->page_title );
 330                 }
 331                 return $this->mTitle;
 332         }
 333
 334         /**
 335          * Set the title of the revision
 336          * @param Title $title
 337          */
 338         function setTitle( $title ) {
 339                 $this->mTitle = $title;
 340         }
 341
 342         /**
 343          * @return int
 344          */
 345         function getPage() {
 346                 return $this->mPage;
 347         }
 348
 349         /**
 350          * Fetch revision's user id if it's available to all users
 351          * @return int
 352          */
 353         function getUser() {
 354                 if( $this->isDeleted( self::DELETED_USER ) ) {
 355                         return 0;
 356                 } else {
 357                         return $this->mUser;
 358                 }
 359         }
 360
 361         /**
 362          * Fetch revision's user id without regard for the current user's permissions
 363          * @return string
 364          */
 365         function getRawUser() {
 366                 return $this->mUser;
 367         }
 368
 369         /**
 370          * Fetch revision's username if it's available to all users
 371          * @return string
 372          */
 373         function getUserText() {
 374                 if( $this->isDeleted( self::DELETED_USER ) ) {
 375                         return "";
 376                 } else {
 377                         return $this->mUserText;
 378                 }
 379         }
 380
 381         /**
 382          * Fetch revision's username without regard for view restrictions
 383          * @return string
 384          */
 385         function getRawUserText() {
 386                 return $this->mUserText;
 387         }
 388
 389         /**
 390          * Fetch revision comment if it's available to all users
 391          * @return string
 392          */
 393         function getComment() {
 394                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 395                         return "";
 396                 } else {
 397                         return $this->mComment;
 398                 }
 399         }
 400
 401         /**
 402          * Fetch revision comment without regard for the current user's permissions
 403          * @return string
 404          */
 405         function getRawComment() {
 406                 return $this->mComment;
 407         }
 408
 409         /**
 410          * @return bool
 411          */
 412         function isMinor() {
 413                 return (bool)$this->mMinorEdit;
 414         }
 415
 416         /**
 417          * int $field one of DELETED_* bitfield constants
 418          * @return bool
 419          */
 420         function isDeleted( $field ) {
 421                 return ($this->mDeleted & $field) == $field;
 422         }
 423
 424         /**
 425          * Fetch revision text if it's available to all users
 426          * @return string
 427          */
 428         function getText() {
 429                 if( $this->isDeleted( self::DELETED_TEXT ) ) {
 430                         return "";
 431                 } else {
 432                         return $this->getRawText();
 433                 }
 434         }
 435
 436         /**
 437          * Fetch revision text without regard for view restrictions
 438          * @return string
 439          */
 440         function getRawText() {
 441                 if( is_null( $this->mText ) ) {
 442                         // Revision text is immutable. Load on demand:
 443                         $this->mText = $this->loadText();
 444                 }
 445                 return $this->mText;
 446         }
 447
 448         /**
 449          * @return string
 450          */
 451         function getTimestamp() {
 452                 return wfTimestamp(TS_MW, $this->mTimestamp);
 453         }
 454
 455         /**
 456          * @return bool
 457          */
 458         function isCurrent() {
 459                 return $this->mCurrent;
 460         }
 461
 462         /**
 463          * @return Revision
 464          */
 465         function getPrevious() {
 466                 $prev = $this->mTitle->getPreviousRevisionID( $this->mId );
 467                 if ( $prev ) {
 468                         return Revision::newFromTitle( $this->mTitle, $prev );
 469                 } else {
 470                         return null;
 471                 }
 472         }
 473
 474         /**
 475          * @return Revision
 476          */
 477         function getNext() {
 478                 $next = $this->mTitle->getNextRevisionID( $this->mId );
 479                 if ( $next ) {
 480                         return Revision::newFromTitle( $this->mTitle, $next );
 481                 } else {
 482                         return null;
 483                 }
 484         }
 485         /**#@-*/
 486
 487         /**
 488           * Get revision text associated with an old or archive row
 489           * $row is usually an object from wfFetchRow(), both the flags and the text
 490           * field must be included
 491           * @static
 492           * @param integer $row Id of a row
 493           * @param string $prefix table prefix (default 'old_')
 494           * @return string $text|false the text requested
 495           */
 496         function getRevisionText( $row, $prefix = 'old_' ) {
 497                 $fname = 'Revision::getRevisionText';
 498                 wfProfileIn( $fname );
 499
 500                 # Get data
 501                 $textField = $prefix . 'text';
 502                 $flagsField = $prefix . 'flags';
 503
 504                 if( isset( $row->$flagsField ) ) {
 505                         $flags = explode( ',', $row->$flagsField );
 506                 } else {
 507                         $flags = array();
 508                 }
 509
 510                 if( isset( $row->$textField ) ) {
 511                         $text = $row->$textField;
 512                 } else {
 513                         wfProfileOut( $fname );
 514                         return false;
 515                 }
 516
 517                 # Use external methods for external objects, text in table is URL-only then
 518                 if ( in_array( 'external', $flags ) ) {
 519                         $url=$text;
 520                         @list($proto,$path)=explode('://',$url,2);
 521                         if ($path=="") {
 522                                 wfProfileOut( $fname );
 523                                 return false;
 524                         }
 525                         require_once('ExternalStore.php');
 526                         $text=ExternalStore::fetchFromURL($url);
 527                 }
 528
 529                 // If the text was fetched without an error, convert it
 530                 if ( $text !== false ) {
 531                         if( in_array( 'gzip', $flags ) ) {
 532                                 # Deal with optional compression of archived pages.
 533                                 # This can be done periodically via maintenance/compressOld.php, and
 534                                 # as pages are saved if $wgCompressRevisions is set.
 535                                 $text = gzinflate( $text );
 536                         }
 537
 538                         if( in_array( 'object', $flags ) ) {
 539                                 # Generic compressed storage
 540                                 $obj = unserialize( $text );
 541                                 if ( !is_object( $obj ) ) {
 542                                         // Invalid object
 543                                         wfProfileOut( $fname );
 544                                         return false;
 545                                 }
 546                                 $text = $obj->getText();
 547                         }
 548
 549                         global $wgLegacyEncoding;
 550                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 551                                 # Old revisions kept around in a legacy encoding?
 552                                 # Upconvert on demand.
 553                                 global $wgInputEncoding, $wgContLang;
 554                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding . '//IGNORE', $text );
 555                         }
 556                 }
 557                 wfProfileOut( $fname );
 558                 return $text;
 559         }
 560
 561         /**
 562          * If $wgCompressRevisions is enabled, we will compress data.
 563          * The input string is modified in place.
 564          * Return value is the flags field: contains 'gzip' if the
 565          * data is compressed, and 'utf-8' if we're saving in UTF-8
 566          * mode.
 567          *
 568          * @static
 569          * @param mixed $text reference to a text
 570          * @return string
 571          */
 572         function compressRevisionText( &$text ) {
 573                 global $wgCompressRevisions;
 574                 $flags = array();
 575
 576                 # Revisions not marked this way will be converted
 577                 # on load if $wgLegacyCharset is set in the future.
 578                 $flags[] = 'utf-8';
 579
 580                 if( $wgCompressRevisions ) {
 581                         if( function_exists( 'gzdeflate' ) ) {
 582                                 $text = gzdeflate( $text );
 583                                 $flags[] = 'gzip';
 584                         } else {
 585                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 586                         }
 587                 }
 588                 return implode( ',', $flags );
 589         }
 590
 591         /**
 592          * Insert a new revision into the database, returning the new revision ID
 593          * number on success and dies horribly on failure.
 594          *
 595          * @param Database $dbw
 596          * @return int
 597          */
 598         function insertOn( &$dbw ) {
 599                 global $wgDefaultExternalStore;
 600
 601                 $fname = 'Revision::insertOn';
 602                 wfProfileIn( $fname );
 603
 604                 $data = $this->mText;
 605                 $flags = Revision::compressRevisionText( $data );
 606
 607                 # Write to external storage if required
 608                 if ( $wgDefaultExternalStore ) {
 609                         if ( is_array( $wgDefaultExternalStore ) ) {
 610                                 // Distribute storage across multiple clusters
 611                                 $store = $wgDefaultExternalStore[mt_rand(0, count( $wgDefaultExternalStore ) - 1)];
 612                         } else {
 613                                 $store = $wgDefaultExternalStore;
 614                         }
 615                         require_once('ExternalStore.php');
 616                         // Store and get the URL
 617                         $data = ExternalStore::insert( $store, $data );
 618                         if ( !$data ) {
 619                                 # This should only happen in the case of a configuration error, where the external store is not valid
 620                                 throw new MWException( "Unable to store text to external storage $store" );
 621                         }
 622                         if ( $flags ) {
 623                                 $flags .= ',';
 624                         }
 625                         $flags .= 'external';
 626                 }
 627
 628                 # Record the text (or external storage URL) to the text table
 629                 if( !isset( $this->mTextId ) ) {
 630                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 631                         $dbw->insert( 'text',
 632                                 array(
 633                                         'old_id'    => $old_id,
 634                                         'old_text'  => $data,
 635                                         'old_flags' => $flags,
 636                                 ), $fname
 637                         );
 638                         $this->mTextId = $dbw->insertId();
 639                 }
 640
 641                 # Record the edit in revisions
 642                 $rev_id = isset( $this->mId )
 643                         ? $this->mId
 644                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 645                 $dbw->insert( 'revision',
 646                         array(
 647                                 'rev_id'         => $rev_id,
 648                                 'rev_page'       => $this->mPage,
 649                                 'rev_text_id'    => $this->mTextId,
 650                                 'rev_comment'    => $this->mComment,
 651                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 652                                 'rev_user'       => $this->mUser,
 653                                 'rev_user_text'  => $this->mUserText,
 654                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 655                                 'rev_deleted'    => $this->mDeleted,
 656                         ), $fname
 657                 );
 658
 659                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 660                 wfProfileOut( $fname );
 661                 return $this->mId;
 662         }
 663
 664         /**
 665          * Lazy-load the revision's text.
 666          * Currently hardcoded to the 'text' table storage engine.
 667          *
 668          * @return string
 669          * @access private
 670          */
 671         function loadText() {
 672                 $fname = 'Revision::loadText';
 673                 wfProfileIn( $fname );
 674
 675                 // Caching may be beneficial for massive use of external storage
 676                 global $wgRevisionCacheExpiry, $wgMemc, $wgDBname;
 677                 $key = "$wgDBname:revisiontext:textid:" . $this->getTextId();
 678                 if( $wgRevisionCacheExpiry ) {
 679                         $text = $wgMemc->get( $key );
 680                         if( is_string( $text ) ) {
 681                                 wfProfileOut( $fname );
 682                                 return $text;
 683                         }
 684                 }
 685
 686                 // If we kept data for lazy extraction, use it now...
 687                 $row = $this->mTextRow;
 688                 $this->mTextRow = null;
 689
 690                 if( !$row ) {
 691                         // Text data is immutable; check slaves first.
 692                         $dbr =& wfGetDB( DB_SLAVE );
 693                         $row = $dbr->selectRow( 'text',
 694                                 array( 'old_text', 'old_flags' ),
 695                                 array( 'old_id' => $this->getTextId() ),
 696                                 $fname);
 697                 }
 698
 699                 if( !$row ) {
 700                         // Possible slave lag!
 701                         $dbw =& wfGetDB( DB_MASTER );
 702                         $row = $dbw->selectRow( 'text',
 703                                 array( 'old_text', 'old_flags' ),
 704                                 array( 'old_id' => $this->getTextId() ),
 705                                 $fname);
 706                 }
 707
 708                 $text = Revision::getRevisionText( $row );
 709
 710                 if( $wgRevisionCacheExpiry ) {
 711                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 712                 }
 713
 714                 wfProfileOut( $fname );
 715
 716                 return $text;
 717         }
 718
 719         /**
 720          * Create a new null-revision for insertion into a page's
 721          * history. This will not re-save the text, but simply refer
 722          * to the text from the previous version.
 723          *
 724          * Such revisions can for instance identify page rename
 725          * operations and other such meta-modifications.
 726          *
 727          * @param Database $dbw
 728          * @param int      $pageId ID number of the page to read from
 729          * @param string   $summary
 730          * @param bool     $minor
 731          * @return Revision
 732          */
 733         function newNullRevision( &$dbw, $pageId, $summary, $minor ) {
 734                 $fname = 'Revision::newNullRevision';
 735                 wfProfileIn( $fname );
 736
 737                 $current = $dbw->selectRow(
 738                         array( 'page', 'revision' ),
 739                         array( 'page_latest', 'rev_text_id' ),
 740                         array(
 741                                 'page_id' => $pageId,
 742                                 'page_latest=rev_id',
 743                                 ),
 744                         $fname );
 745
 746                 if( $current ) {
 747                         $revision = new Revision( array(
 748                                 'page'       => $pageId,
 749                                 'comment'    => $summary,
 750                                 'minor_edit' => $minor,
 751                                 'text_id'    => $current->rev_text_id,
 752                                 ) );
 753                 } else {
 754                         $revision = null;
 755                 }
 756
 757                 wfProfileOut( $fname );
 758                 return $revision;
 759         }
 760
 761         /**
 762          * Determine if the current user is allowed to view a particular
 763          * field of this revision, if it's marked as deleted.
 764          * @param int $field one of self::DELETED_TEXT,
 765          *                          self::DELETED_COMMENT,
 766          *                          self::DELETED_USER
 767          * @return bool
 768          */
 769         function userCan( $field ) {
 770                 if( ( $this->mDeleted & $field ) == $field ) {
 771                         global $wgUser;
 772                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 773                                 ? 'hiderevision'
 774                                 : 'deleterevision';
 775                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 776                         return $wgUser->isAllowed( $permission );
 777                 } else {
 778                         return true;
 779                 }
 780         }
 781
 782
 783         /**
 784          * Get rev_timestamp from rev_id, without loading the rest of the row
 785          * @param integer $id
 786          */
 787         static function getTimestampFromID( $id ) {
 788                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp',
 789                         array( 'rev_id' => $id ), __METHOD__ );
 790                 if ( $timestamp === false ) {
 791                         # Not in slave, try master
 792                         $dbw =& wfGetDB( DB_MASTER );
 793                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp',
 794                                 array( 'rev_id' => $id ), __METHOD__ );
 795                 }
 796                 return $timestamp;
 797         }
 798
 799         static function countByPageId( $db, $id ) {
 800                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 801                         array( 'rev_page' => $id ), __METHOD__ );
 802                 if( $row ) {
 803                         return $row->revCount;
 804                 }
 805                 return 0;
 806         }
 807
 808         static function countByTitle( $db, $title ) {
 809                 $id = $title->getArticleId();
 810                 if( $id ) {
 811                         return Revision::countByPageId( $db, $id );
 812                 }
 813                 return 0;
 814         }
 815 }
 816
 817 /**
 818  * Aliases for backwards compatibility with 1.6
 819  */
 820 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 821 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 822 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 823 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );
 824
 825
 826 ?>