includes/Revision.php

   1 <?php
   2 /**
   3  * @package MediaWiki
   4  * @todo document
   5  */
   6
   7 /**
   8  * @package MediaWiki
   9  * @todo document
  10  */
  11 class Revision {
  12         const DELETED_TEXT      = 1;
  13         const DELETED_COMMENT   = 2;
  14         const DELETED_USER      = 4;
  15         const DELETED_RESTRICTED = 8;
  16
  17         /**
  18          * Load a page revision from a given revision ID number.
  19          * Returns null if no such revision can be found.
  20          *
  21          * @param int $id
  22          * @access public
  23          * @static
  24          */
  25         public static function newFromId( $id ) {
  26                 return Revision::newFromConds(
  27                         array( 'page_id=rev_page',
  28                                'rev_id' => intval( $id ) ) );
  29         }
  30
  31         /**
  32          * Load either the current, or a specified, revision
  33          * that's attached to a given title. If not attached
  34          * to that title, will return null.
  35          *
  36          * @param Title $title
  37          * @param int $id
  38          * @return Revision
  39          * @access public
  40          * @static
  41          */
  42         public static function newFromTitle( &$title, $id = 0 ) {
  43                 if( $id ) {
  44                         $matchId = intval( $id );
  45                 } else {
  46                         $matchId = 'page_latest';
  47                 }
  48                 return Revision::newFromConds(
  49                         array( "rev_id=$matchId",
  50                                'page_id=rev_page',
  51                                'page_namespace' => $title->getNamespace(),
  52                                'page_title'     => $title->getDbkey() ) );
  53         }
  54
  55         /**
  56          * Load a page revision from a given revision ID number.
  57          * Returns null if no such revision can be found.
  58          *
  59          * @param Database $db
  60          * @param int $id
  61          * @access public
  62          * @static
  63          */
  64         public static function loadFromId( &$db, $id ) {
  65                 return Revision::loadFromConds( $db,
  66                         array( 'page_id=rev_page',
  67                                'rev_id' => intval( $id ) ) );
  68         }
  69
  70         /**
  71          * Load either the current, or a specified, revision
  72          * that's attached to a given page. If not attached
  73          * to that page, will return null.
  74          *
  75          * @param Database $db
  76          * @param int $pageid
  77          * @param int $id
  78          * @return Revision
  79          * @access public
  80          * @static
  81          */
  82         public static function loadFromPageId( &$db, $pageid, $id = 0 ) {
  83                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  84                 if( $id ) {
  85                         $conds['rev_id']=intval($id);
  86                 } else {
  87                         $conds[]='rev_id=page_latest';
  88                 }
  89                 return Revision::loadFromConds( $db, $conds );
  90         }
  91
  92         /**
  93          * Load either the current, or a specified, revision
  94          * that's attached to a given page. If not attached
  95          * to that page, will return null.
  96          *
  97          * @param Database $db
  98          * @param Title $title
  99          * @param int $id
 100          * @return Revision
 101          * @access public
 102          * @static
 103          */
 104         public static function loadFromTitle( &$db, $title, $id = 0 ) {
 105                 if( $id ) {
 106                         $matchId = intval( $id );
 107                 } else {
 108                         $matchId = 'page_latest';
 109                 }
 110                 return Revision::loadFromConds(
 111                         $db,
 112                         array( "rev_id=$matchId",
 113                                'page_id=rev_page',
 114                                'page_namespace' => $title->getNamespace(),
 115                                'page_title'     => $title->getDbkey() ) );
 116         }
 117
 118         /**
 119          * Load the revision for the given title with the given timestamp.
 120          * WARNING: Timestamps may in some circumstances not be unique,
 121          * so this isn't the best key to use.
 122          *
 123          * @param Database $db
 124          * @param Title $title
 125          * @param string $timestamp
 126          * @return Revision
 127          * @access public
 128          * @static
 129          */
 130         public static function loadFromTimestamp( &$db, &$title, $timestamp ) {
 131                 return Revision::loadFromConds(
 132                         $db,
 133                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 134                                'page_id=rev_page',
 135                                'page_namespace' => $title->getNamespace(),
 136                                'page_title'     => $title->getDbkey() ) );
 137         }
 138
 139         /**
 140          * Given a set of conditions, fetch a revision.
 141          *
 142          * @param array $conditions
 143          * @return Revision
 144          * @access private
 145          * @static
 146          */
 147         private static function newFromConds( $conditions ) {
 148                 $db =& wfGetDB( DB_SLAVE );
 149                 $row = Revision::loadFromConds( $db, $conditions );
 150                 if( is_null( $row ) ) {
 151                         $dbw =& wfGetDB( DB_MASTER );
 152                         $row = Revision::loadFromConds( $dbw, $conditions );
 153                 }
 154                 return $row;
 155         }
 156
 157         /**
 158          * Given a set of conditions, fetch a revision from
 159          * the given database connection.
 160          *
 161          * @param Database $db
 162          * @param array $conditions
 163          * @return Revision
 164          * @access private
 165          * @static
 166          */
 167         private static function loadFromConds( &$db, $conditions ) {
 168                 $res = Revision::fetchFromConds( $db, $conditions );
 169                 if( $res ) {
 170                         $row = $res->fetchObject();
 171                         $res->free();
 172                         if( $row ) {
 173                                 $ret = new Revision( $row );
 174                                 return $ret;
 175                         }
 176                 }
 177                 $ret = null;
 178                 return $ret;
 179         }
 180
 181         /**
 182          * Return a wrapper for a series of database rows to
 183          * fetch all of a given page's revisions in turn.
 184          * Each row can be fed to the constructor to get objects.
 185          *
 186          * @param Title $title
 187          * @return ResultWrapper
 188          * @access public
 189          * @static
 190          */
 191         public static function fetchAllRevisions( &$title ) {
 192                 return Revision::fetchFromConds(
 193                         wfGetDB( DB_SLAVE ),
 194                         array( 'page_namespace' => $title->getNamespace(),
 195                                'page_title'     => $title->getDbkey(),
 196                                'page_id=rev_page' ) );
 197         }
 198
 199         /**
 200          * Return a wrapper for a series of database rows to
 201          * fetch all of a given page's revisions in turn.
 202          * Each row can be fed to the constructor to get objects.
 203          *
 204          * @param Title $title
 205          * @return ResultWrapper
 206          * @access public
 207          * @static
 208          */
 209         public static function fetchRevision( &$title ) {
 210                 return Revision::fetchFromConds(
 211                         wfGetDB( DB_SLAVE ),
 212                         array( 'rev_id=page_latest',
 213                                'page_namespace' => $title->getNamespace(),
 214                                'page_title'     => $title->getDbkey(),
 215                                'page_id=rev_page' ) );
 216         }
 217
 218         /**
 219          * Given a set of conditions, return a ResultWrapper
 220          * which will return matching database rows with the
 221          * fields necessary to build Revision objects.
 222          *
 223          * @param Database $db
 224          * @param array $conditions
 225          * @return ResultWrapper
 226          * @access private
 227          * @static
 228          */
 229         private static function fetchFromConds( &$db, $conditions ) {
 230                 $res = $db->select(
 231                         array( 'page', 'revision' ),
 232                         array( 'page_namespace',
 233                                'page_title',
 234                                'page_latest',
 235                                'rev_id',
 236                                'rev_page',
 237                                'rev_text_id',
 238                                'rev_comment',
 239                                'rev_user_text',
 240                                'rev_user',
 241                                'rev_minor_edit',
 242                                'rev_timestamp',
 243                                'rev_deleted' ),
 244                         $conditions,
 245                         'Revision::fetchRow',
 246                         array( 'LIMIT' => 1 ) );
 247                 $ret = $db->resultObject( $res );
 248                 return $ret;
 249         }
 250
 251         /**
 252          * @param object $row
 253          * @access private
 254          */
 255         function Revision( $row ) {
 256                 if( is_object( $row ) ) {
 257                         $this->mId        = intval( $row->rev_id );
 258                         $this->mPage      = intval( $row->rev_page );
 259                         $this->mTextId    = intval( $row->rev_text_id );
 260                         $this->mComment   =         $row->rev_comment;
 261                         $this->mUserText  =         $row->rev_user_text;
 262                         $this->mUser      = intval( $row->rev_user );
 263                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 264                         $this->mTimestamp =         $row->rev_timestamp;
 265                         $this->mDeleted   = intval( $row->rev_deleted );
 266
 267                         if( isset( $row->page_latest ) ) {
 268                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 269                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 270                                                                       $row->page_title );
 271                         } else {
 272                                 $this->mCurrent = false;
 273                                 $this->mTitle = null;
 274                         }
 275
 276                         // Lazy extraction...
 277                         $this->mText      = null;
 278                         if( isset( $row->old_text ) ) {
 279                                 $this->mTextRow = $row;
 280                         } else {
 281                                 // 'text' table row entry will be lazy-loaded
 282                                 $this->mTextRow = null;
 283                         }
 284                 } elseif( is_array( $row ) ) {
 285                         // Build a new revision to be saved...
 286                         global $wgUser;
 287
 288                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 289                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 290                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 291                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 292                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 293                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 294                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 295                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 296
 297                         // Enforce spacing trimming on supplied text
 298                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 299                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 300                         $this->mTextRow   = null;
 301
 302                         $this->mTitle     = null; # Load on demand if needed
 303                         $this->mCurrent   = false;
 304                 } else {
 305                         throw new MWException( 'Revision constructor passed invalid row format.' );
 306                 }
 307         }
 308
 309         /**#@+
 310          * @access public
 311          */
 312
 313         /**
 314          * @return int
 315          */
 316         function getId() {
 317                 return $this->mId;
 318         }
 319
 320         /**
 321          * @return int
 322          */
 323         function getTextId() {
 324                 return $this->mTextId;
 325         }
 326
 327         /**
 328          * Returns the title of the page associated with this entry.
 329          * @return Title
 330          */
 331         function getTitle() {
 332                 if( isset( $this->mTitle ) ) {
 333                         return $this->mTitle;
 334                 }
 335                 $dbr =& wfGetDB( DB_SLAVE );
 336                 $row = $dbr->selectRow(
 337                         array( 'page', 'revision' ),
 338                         array( 'page_namespace', 'page_title' ),
 339                         array( 'page_id=rev_page',
 340                                'rev_id' => $this->mId ),
 341                         'Revision::getTitle' );
 342                 if( $row ) {
 343                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 344                                                            $row->page_title );
 345                 }
 346                 return $this->mTitle;
 347         }
 348
 349         /**
 350          * Set the title of the revision
 351          * @param Title $title
 352          */
 353         function setTitle( $title ) {
 354                 $this->mTitle = $title;
 355         }
 356
 357         /**
 358          * @return int
 359          */
 360         function getPage() {
 361                 return $this->mPage;
 362         }
 363
 364         /**
 365          * Fetch revision's user id if it's available to all users
 366          * @return int
 367          */
 368         function getUser() {
 369                 if( $this->isDeleted( self::DELETED_USER ) ) {
 370                         return 0;
 371                 } else {
 372                         return $this->mUser;
 373                 }
 374         }
 375
 376         /**
 377          * Fetch revision's user id without regard for the current user's permissions
 378          * @return string
 379          */
 380         function getRawUser() {
 381                 return $this->mUser;
 382         }
 383
 384         /**
 385          * Fetch revision's username if it's available to all users
 386          * @return string
 387          */
 388         function getUserText() {
 389                 if( $this->isDeleted( self::DELETED_USER ) ) {
 390                         return "";
 391                 } else {
 392                         return $this->mUserText;
 393                 }
 394         }
 395
 396         /**
 397          * Fetch revision's username without regard for view restrictions
 398          * @return string
 399          */
 400         function getRawUserText() {
 401                 return $this->mUserText;
 402         }
 403
 404         /**
 405          * Fetch revision comment if it's available to all users
 406          * @return string
 407          */
 408         function getComment() {
 409                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 410                         return "";
 411                 } else {
 412                         return $this->mComment;
 413                 }
 414         }
 415
 416         /**
 417          * Fetch revision comment without regard for the current user's permissions
 418          * @return string
 419          */
 420         function getRawComment() {
 421                 return $this->mComment;
 422         }
 423
 424         /**
 425          * @return bool
 426          */
 427         function isMinor() {
 428                 return (bool)$this->mMinorEdit;
 429         }
 430
 431         /**
 432          * int $field one of DELETED_* bitfield constants
 433          * @return bool
 434          */
 435         function isDeleted( $field ) {
 436                 return ($this->mDeleted & $field) == $field;
 437         }
 438
 439         /**
 440          * Fetch revision text if it's available to all users
 441          * @return string
 442          */
 443         function getText() {
 444                 if( $this->isDeleted( self::DELETED_TEXT ) ) {
 445                         return "";
 446                 } else {
 447                         return $this->getRawText();
 448                 }
 449         }
 450
 451         /**
 452          * Fetch revision text without regard for view restrictions
 453          * @return string
 454          */
 455         function getRawText() {
 456                 if( is_null( $this->mText ) ) {
 457                         // Revision text is immutable. Load on demand:
 458                         $this->mText = $this->loadText();
 459                 }
 460                 return $this->mText;
 461         }
 462
 463         /**
 464          * @return string
 465          */
 466         function getTimestamp() {
 467                 return wfTimestamp(TS_MW, $this->mTimestamp);
 468         }
 469
 470         /**
 471          * @return bool
 472          */
 473         function isCurrent() {
 474                 return $this->mCurrent;
 475         }
 476
 477         /**
 478          * @return Revision
 479          */
 480         function getPrevious() {
 481                 $prev = $this->mTitle->getPreviousRevisionID( $this->mId );
 482                 if ( $prev ) {
 483                         return Revision::newFromTitle( $this->mTitle, $prev );
 484                 } else {
 485                         return null;
 486                 }
 487         }
 488
 489         /**
 490          * @return Revision
 491          */
 492         function getNext() {
 493                 $next = $this->mTitle->getNextRevisionID( $this->mId );
 494                 if ( $next ) {
 495                         return Revision::newFromTitle( $this->mTitle, $next );
 496                 } else {
 497                         return null;
 498                 }
 499         }
 500         /**#@-*/
 501
 502         /**
 503           * Get revision text associated with an old or archive row
 504           * $row is usually an object from wfFetchRow(), both the flags and the text
 505           * field must be included
 506           * @static
 507           * @param integer $row Id of a row
 508           * @param string $prefix table prefix (default 'old_')
 509           * @return string $text|false the text requested
 510           */
 511         public static function getRevisionText( $row, $prefix = 'old_' ) {
 512                 $fname = 'Revision::getRevisionText';
 513                 wfProfileIn( $fname );
 514
 515                 # Get data
 516                 $textField = $prefix . 'text';
 517                 $flagsField = $prefix . 'flags';
 518
 519                 if( isset( $row->$flagsField ) ) {
 520                         $flags = explode( ',', $row->$flagsField );
 521                 } else {
 522                         $flags = array();
 523                 }
 524
 525                 if( isset( $row->$textField ) ) {
 526                         $text = $row->$textField;
 527                 } else {
 528                         wfProfileOut( $fname );
 529                         return false;
 530                 }
 531
 532                 # Use external methods for external objects, text in table is URL-only then
 533                 if ( in_array( 'external', $flags ) ) {
 534                         $url=$text;
 535                         @list(/* $proto */,$path)=explode('://',$url,2);
 536                         if ($path=="") {
 537                                 wfProfileOut( $fname );
 538                                 return false;
 539                         }
 540                         $text=ExternalStore::fetchFromURL($url);
 541                 }
 542
 543                 // If the text was fetched without an error, convert it
 544                 if ( $text !== false ) {
 545                         if( in_array( 'gzip', $flags ) ) {
 546                                 # Deal with optional compression of archived pages.
 547                                 # This can be done periodically via maintenance/compressOld.php, and
 548                                 # as pages are saved if $wgCompressRevisions is set.
 549                                 $text = gzinflate( $text );
 550                         }
 551
 552                         if( in_array( 'object', $flags ) ) {
 553                                 # Generic compressed storage
 554                                 $obj = unserialize( $text );
 555                                 if ( !is_object( $obj ) ) {
 556                                         // Invalid object
 557                                         wfProfileOut( $fname );
 558                                         return false;
 559                                 }
 560                                 $text = $obj->getText();
 561                         }
 562
 563                         global $wgLegacyEncoding;
 564                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 565                                 # Old revisions kept around in a legacy encoding?
 566                                 # Upconvert on demand.
 567                                 global $wgInputEncoding, $wgContLang;
 568                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding . '//IGNORE', $text );
 569                         }
 570                 }
 571                 wfProfileOut( $fname );
 572                 return $text;
 573         }
 574
 575         /**
 576          * If $wgCompressRevisions is enabled, we will compress data.
 577          * The input string is modified in place.
 578          * Return value is the flags field: contains 'gzip' if the
 579          * data is compressed, and 'utf-8' if we're saving in UTF-8
 580          * mode.
 581          *
 582          * @static
 583          * @param mixed $text reference to a text
 584          * @return string
 585          */
 586         function compressRevisionText( &$text ) {
 587                 global $wgCompressRevisions;
 588                 $flags = array();
 589
 590                 # Revisions not marked this way will be converted
 591                 # on load if $wgLegacyCharset is set in the future.
 592                 $flags[] = 'utf-8';
 593
 594                 if( $wgCompressRevisions ) {
 595                         if( function_exists( 'gzdeflate' ) ) {
 596                                 $text = gzdeflate( $text );
 597                                 $flags[] = 'gzip';
 598                         } else {
 599                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 600                         }
 601                 }
 602                 return implode( ',', $flags );
 603         }
 604
 605         /**
 606          * Insert a new revision into the database, returning the new revision ID
 607          * number on success and dies horribly on failure.
 608          *
 609          * @param Database $dbw
 610          * @return int
 611          */
 612         function insertOn( &$dbw ) {
 613                 global $wgDefaultExternalStore;
 614
 615                 $fname = 'Revision::insertOn';
 616                 wfProfileIn( $fname );
 617
 618                 $data = $this->mText;
 619                 $flags = Revision::compressRevisionText( $data );
 620
 621                 # Write to external storage if required
 622                 if ( $wgDefaultExternalStore ) {
 623                         if ( is_array( $wgDefaultExternalStore ) ) {
 624                                 // Distribute storage across multiple clusters
 625                                 $store = $wgDefaultExternalStore[mt_rand(0, count( $wgDefaultExternalStore ) - 1)];
 626                         } else {
 627                                 $store = $wgDefaultExternalStore;
 628                         }
 629                         // Store and get the URL
 630                         $data = ExternalStore::insert( $store, $data );
 631                         if ( !$data ) {
 632                                 # This should only happen in the case of a configuration error, where the external store is not valid
 633                                 throw new MWException( "Unable to store text to external storage $store" );
 634                         }
 635                         if ( $flags ) {
 636                                 $flags .= ',';
 637                         }
 638                         $flags .= 'external';
 639                 }
 640
 641                 # Record the text (or external storage URL) to the text table
 642                 if( !isset( $this->mTextId ) ) {
 643                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 644                         $dbw->insert( 'text',
 645                                 array(
 646                                         'old_id'    => $old_id,
 647                                         'old_text'  => $data,
 648                                         'old_flags' => $flags,
 649                                 ), $fname
 650                         );
 651                         $this->mTextId = $dbw->insertId();
 652                 }
 653
 654                 # Record the edit in revisions
 655                 $rev_id = isset( $this->mId )
 656                         ? $this->mId
 657                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 658                 $dbw->insert( 'revision',
 659                         array(
 660                                 'rev_id'         => $rev_id,
 661                                 'rev_page'       => $this->mPage,
 662                                 'rev_text_id'    => $this->mTextId,
 663                                 'rev_comment'    => $this->mComment,
 664                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 665                                 'rev_user'       => $this->mUser,
 666                                 'rev_user_text'  => $this->mUserText,
 667                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 668                                 'rev_deleted'    => $this->mDeleted,
 669                         ), $fname
 670                 );
 671
 672                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 673                 wfProfileOut( $fname );
 674                 return $this->mId;
 675         }
 676
 677         /**
 678          * Lazy-load the revision's text.
 679          * Currently hardcoded to the 'text' table storage engine.
 680          *
 681          * @return string
 682          * @access private
 683          */
 684         function loadText() {
 685                 $fname = 'Revision::loadText';
 686                 wfProfileIn( $fname );
 687
 688                 // Caching may be beneficial for massive use of external storage
 689                 global $wgRevisionCacheExpiry, $wgMemc;
 690                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 691                 if( $wgRevisionCacheExpiry ) {
 692                         $text = $wgMemc->get( $key );
 693                         if( is_string( $text ) ) {
 694                                 wfProfileOut( $fname );
 695                                 return $text;
 696                         }
 697                 }
 698
 699                 // If we kept data for lazy extraction, use it now...
 700                 if ( isset( $this->mTextRow ) ) {
 701                         $row = $this->mTextRow;
 702                         $this->mTextRow = null;
 703                 } else {
 704                         $row = null;
 705                 }
 706
 707                 if( !$row ) {
 708                         // Text data is immutable; check slaves first.
 709                         $dbr =& wfGetDB( DB_SLAVE );
 710                         $row = $dbr->selectRow( 'text',
 711                                 array( 'old_text', 'old_flags' ),
 712                                 array( 'old_id' => $this->getTextId() ),
 713                                 $fname);
 714                 }
 715
 716                 if( !$row ) {
 717                         // Possible slave lag!
 718                         $dbw =& wfGetDB( DB_MASTER );
 719                         $row = $dbw->selectRow( 'text',
 720                                 array( 'old_text', 'old_flags' ),
 721                                 array( 'old_id' => $this->getTextId() ),
 722                                 $fname);
 723                 }
 724
 725                 $text = Revision::getRevisionText( $row );
 726
 727                 if( $wgRevisionCacheExpiry ) {
 728                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 729                 }
 730
 731                 wfProfileOut( $fname );
 732
 733                 return $text;
 734         }
 735
 736         /**
 737          * Create a new null-revision for insertion into a page's
 738          * history. This will not re-save the text, but simply refer
 739          * to the text from the previous version.
 740          *
 741          * Such revisions can for instance identify page rename
 742          * operations and other such meta-modifications.
 743          *
 744          * @param Database $dbw
 745          * @param int      $pageId ID number of the page to read from
 746          * @param string   $summary
 747          * @param bool     $minor
 748          * @return Revision
 749          */
 750         function newNullRevision( &$dbw, $pageId, $summary, $minor ) {
 751                 $fname = 'Revision::newNullRevision';
 752                 wfProfileIn( $fname );
 753
 754                 $current = $dbw->selectRow(
 755                         array( 'page', 'revision' ),
 756                         array( 'page_latest', 'rev_text_id' ),
 757                         array(
 758                                 'page_id' => $pageId,
 759                                 'page_latest=rev_id',
 760                                 ),
 761                         $fname );
 762
 763                 if( $current ) {
 764                         $revision = new Revision( array(
 765                                 'page'       => $pageId,
 766                                 'comment'    => $summary,
 767                                 'minor_edit' => $minor,
 768                                 'text_id'    => $current->rev_text_id,
 769                                 ) );
 770                 } else {
 771                         $revision = null;
 772                 }
 773
 774                 wfProfileOut( $fname );
 775                 return $revision;
 776         }
 777
 778         /**
 779          * Determine if the current user is allowed to view a particular
 780          * field of this revision, if it's marked as deleted.
 781          * @param int $field one of self::DELETED_TEXT,
 782          *                          self::DELETED_COMMENT,
 783          *                          self::DELETED_USER
 784          * @return bool
 785          */
 786         function userCan( $field ) {
 787                 if( ( $this->mDeleted & $field ) == $field ) {
 788                         global $wgUser;
 789                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 790                                 ? 'hiderevision'
 791                                 : 'deleterevision';
 792                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 793                         return $wgUser->isAllowed( $permission );
 794                 } else {
 795                         return true;
 796                 }
 797         }
 798
 799
 800         /**
 801          * Get rev_timestamp from rev_id, without loading the rest of the row
 802          * @param integer $id
 803          */
 804         static function getTimestampFromID( $id ) {
 805                 $dbr =& wfGetDB( DB_SLAVE );
 806                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp',
 807                         array( 'rev_id' => $id ), __METHOD__ );
 808                 if ( $timestamp === false ) {
 809                         # Not in slave, try master
 810                         $dbw =& wfGetDB( DB_MASTER );
 811                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp',
 812                                 array( 'rev_id' => $id ), __METHOD__ );
 813                 }
 814                 return $timestamp;
 815         }
 816
 817         static function countByPageId( $db, $id ) {
 818                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 819                         array( 'rev_page' => $id ), __METHOD__ );
 820                 if( $row ) {
 821                         return $row->revCount;
 822                 }
 823                 return 0;
 824         }
 825
 826         static function countByTitle( $db, $title ) {
 827                 $id = $title->getArticleId();
 828                 if( $id ) {
 829                         return Revision::countByPageId( $db, $id );
 830                 }
 831                 return 0;
 832         }
 833 }
 834
 835 /**
 836  * Aliases for backwards compatibility with 1.6
 837  */
 838 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 839 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 840 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 841 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );
 842
 843
 844 ?>