includes/Revision.php

   1 <?php
   2 /**
   3  * @todo document
   4  */
   5
   6 /**
   7  * @todo document
   8  */
   9 class Revision {
  10         const DELETED_TEXT = 1;
  11         const DELETED_COMMENT = 2;
  12         const DELETED_USER = 4;
  13     const DELETED_RESTRICTED = 8;
  14     const DELETED_NAME = 16;
  15
  16         /**
  17          * Load a page revision from a given revision ID number.
  18          * Returns null if no such revision can be found.
  19          *
  20          * @param int $id
  21          * @access public
  22          * @static
  23          */
  24         public static function newFromId( $id ) {
  25                 return Revision::newFromConds(
  26                         array( 'page_id=rev_page',
  27                                'rev_id' => intval( $id ) ) );
  28         }
  29
  30         /**
  31          * Load either the current, or a specified, revision
  32          * that's attached to a given title. If not attached
  33          * to that title, will return null.
  34          *
  35          * @param Title $title
  36          * @param int $id
  37          * @return Revision
  38          * @access public
  39          * @static
  40          */
  41         public static function newFromTitle( &$title, $id = 0 ) {
  42                 if( $id ) {
  43                         $matchId = intval( $id );
  44                 } else {
  45                         $matchId = 'page_latest';
  46                 }
  47                 return Revision::newFromConds(
  48                         array( "rev_id=$matchId",
  49                                'page_id=rev_page',
  50                                'page_namespace' => $title->getNamespace(),
  51                                'page_title'     => $title->getDbkey() ) );
  52         }
  53
  54         /**
  55          * Load a page revision from a given revision ID number.
  56          * Returns null if no such revision can be found.
  57          *
  58          * @param Database $db
  59          * @param int $id
  60          * @access public
  61          * @static
  62          */
  63         public static function loadFromId( &$db, $id ) {
  64                 return Revision::loadFromConds( $db,
  65                         array( 'page_id=rev_page',
  66                                'rev_id' => intval( $id ) ) );
  67         }
  68
  69         /**
  70          * Load either the current, or a specified, revision
  71          * that's attached to a given page. If not attached
  72          * to that page, will return null.
  73          *
  74          * @param Database $db
  75          * @param int $pageid
  76          * @param int $id
  77          * @return Revision
  78          * @access public
  79          * @static
  80          */
  81         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
  82                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  83                 if( $id ) {
  84                         $conds['rev_id']=intval($id);
  85                 } else {
  86                         $conds[]='rev_id=page_latest';
  87                 }
  88                 return Revision::loadFromConds( $db, $conds );
  89         }
  90
  91         /**
  92          * Load either the current, or a specified, revision
  93          * that's attached to a given page. If not attached
  94          * to that page, will return null.
  95          *
  96          * @param Database $db
  97          * @param Title $title
  98          * @param int $id
  99          * @return Revision
 100          * @access public
 101          * @static
 102          */
 103         public static function loadFromTitle( &$db, $title, $id = 0 ) {
 104                 if( $id ) {
 105                         $matchId = intval( $id );
 106                 } else {
 107                         $matchId = 'page_latest';
 108                 }
 109                 return Revision::loadFromConds(
 110                         $db,
 111                         array( "rev_id=$matchId",
 112                                'page_id=rev_page',
 113                                'page_namespace' => $title->getNamespace(),
 114                                'page_title'     => $title->getDbkey() ) );
 115         }
 116
 117         /**
 118          * Load the revision for the given title with the given timestamp.
 119          * WARNING: Timestamps may in some circumstances not be unique,
 120          * so this isn't the best key to use.
 121          *
 122          * @param Database $db
 123          * @param Title $title
 124          * @param string $timestamp
 125          * @return Revision
 126          * @access public
 127          * @static
 128          */
 129         public static function loadFromTimestamp( &$db, &$title, $timestamp ) {
 130                 return Revision::loadFromConds(
 131                         $db,
 132                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 133                                'page_id=rev_page',
 134                                'page_namespace' => $title->getNamespace(),
 135                                'page_title'     => $title->getDbkey() ) );
 136         }
 137
 138         /**
 139          * Given a set of conditions, fetch a revision.
 140          *
 141          * @param array $conditions
 142          * @return Revision
 143          * @access private
 144          * @static
 145          */
 146         private static function newFromConds( $conditions ) {
 147                 $db = wfGetDB( DB_SLAVE );
 148                 $row = Revision::loadFromConds( $db, $conditions );
 149                 if( is_null( $row ) ) {
 150                         $dbw = wfGetDB( DB_MASTER );
 151                         $row = Revision::loadFromConds( $dbw, $conditions );
 152                 }
 153                 return $row;
 154         }
 155
 156         /**
 157          * Given a set of conditions, fetch a revision from
 158          * the given database connection.
 159          *
 160          * @param Database $db
 161          * @param array $conditions
 162          * @return Revision
 163          * @access private
 164          * @static
 165          */
 166         private static function loadFromConds( $db, $conditions ) {
 167                 $res = Revision::fetchFromConds( $db, $conditions );
 168                 if( $res ) {
 169                         $row = $res->fetchObject();
 170                         $res->free();
 171                         if( $row ) {
 172                                 $ret = new Revision( $row );
 173                                 return $ret;
 174                         }
 175                 }
 176                 $ret = null;
 177                 return $ret;
 178         }
 179
 180         /**
 181          * Return a wrapper for a series of database rows to
 182          * fetch all of a given page's revisions in turn.
 183          * Each row can be fed to the constructor to get objects.
 184          *
 185          * @param Title $title
 186          * @return ResultWrapper
 187          * @access public
 188          * @static
 189          */
 190         public static function fetchAllRevisions( &$title ) {
 191                 return Revision::fetchFromConds(
 192                         wfGetDB( DB_SLAVE ),
 193                         array( 'page_namespace' => $title->getNamespace(),
 194                                'page_title'     => $title->getDbkey(),
 195                                'page_id=rev_page' ) );
 196         }
 197
 198         /**
 199          * Return a wrapper for a series of database rows to
 200          * fetch all of a given page's revisions in turn.
 201          * Each row can be fed to the constructor to get objects.
 202          *
 203          * @param Title $title
 204          * @return ResultWrapper
 205          * @access public
 206          * @static
 207          */
 208         public static function fetchRevision( &$title ) {
 209                 return Revision::fetchFromConds(
 210                         wfGetDB( DB_SLAVE ),
 211                         array( 'rev_id=page_latest',
 212                                'page_namespace' => $title->getNamespace(),
 213                                'page_title'     => $title->getDbkey(),
 214                                'page_id=rev_page' ) );
 215         }
 216
 217         /**
 218          * Given a set of conditions, return a ResultWrapper
 219          * which will return matching database rows with the
 220          * fields necessary to build Revision objects.
 221          *
 222          * @param Database $db
 223          * @param array $conditions
 224          * @return ResultWrapper
 225          * @access private
 226          * @static
 227          */
 228         private static function fetchFromConds( $db, $conditions ) {
 229                 $res = $db->select(
 230                         array( 'page', 'revision' ),
 231                         array( 'page_namespace',
 232                                'page_title',
 233                                'page_latest',
 234                                'rev_id',
 235                                'rev_page',
 236                                'rev_text_id',
 237                                'rev_comment',
 238                                'rev_user_text',
 239                                'rev_user',
 240                                'rev_minor_edit',
 241                                'rev_timestamp',
 242                                'rev_deleted',
 243                                'rev_len' ),
 244                         $conditions,
 245                         'Revision::fetchRow',
 246                         array( 'LIMIT' => 1 ) );
 247                 $ret = $db->resultObject( $res );
 248                 return $ret;
 249         }
 250
 251         /**
 252          * Return the list of revision fields that should be selected to create
 253          * a new revision.
 254          */
 255         static function selectFields() {
 256                 return array(
 257                         'rev_id',
 258                         'rev_page',
 259                         'rev_text_id',
 260                         'rev_timestamp',
 261                         'rev_comment',
 262                         'rev_minor_edit',
 263                         'rev_user',
 264                         'rev_user_text,'.
 265                         'rev_deleted',
 266                         'rev_len'
 267                 );
 268         }
 269
 270         /**
 271          * @param object $row
 272          * @access private
 273          */
 274         function Revision( $row ) {
 275                 if( is_object( $row ) ) {
 276                         $this->mId        = intval( $row->rev_id );
 277                         $this->mPage      = intval( $row->rev_page );
 278                         $this->mTextId    = intval( $row->rev_text_id );
 279                         $this->mComment   =         $row->rev_comment;
 280                         $this->mUserText  =         $row->rev_user_text;
 281                         $this->mUser      = intval( $row->rev_user );
 282                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 283                         $this->mTimestamp =         $row->rev_timestamp;
 284                         $this->mDeleted   = intval( $row->rev_deleted );
 285
 286                         if( is_null( $row->rev_len ) )
 287                                 $this->mSize = null;
 288                         else
 289                                 $this->mSize = intval( $row->rev_len );
 290
 291                         if( isset( $row->page_latest ) ) {
 292                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 293                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 294                                                                       $row->page_title );
 295                         } else {
 296                                 $this->mCurrent = false;
 297                                 $this->mTitle = null;
 298                         }
 299
 300                         // Lazy extraction...
 301                         $this->mText      = null;
 302                         if( isset( $row->old_text ) ) {
 303                                 $this->mTextRow = $row;
 304                         } else {
 305                                 // 'text' table row entry will be lazy-loaded
 306                                 $this->mTextRow = null;
 307                         }
 308                 } elseif( is_array( $row ) ) {
 309                         // Build a new revision to be saved...
 310                         global $wgUser;
 311
 312                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 313                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 314                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 315                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 316                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 317                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 318                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 319                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 320
 321                         // Enforce spacing trimming on supplied text
 322                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 323                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 324                         $this->mTextRow   = null;
 325
 326                         $this->mTitle     = null; # Load on demand if needed
 327                         $this->mCurrent   = false;
 328
 329                         $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 330                 } else {
 331                         throw new MWException( 'Revision constructor passed invalid row format.' );
 332                 }
 333         }
 334
 335         /**#@+
 336          * @access public
 337          */
 338
 339         /**
 340          * @return int
 341          */
 342         function getId() {
 343                 return $this->mId;
 344         }
 345
 346         /**
 347          * @return int
 348          */
 349         function getTextId() {
 350                 return $this->mTextId;
 351         }
 352
 353         /**
 354          * Returns the length of the text in this revision, or null if unknown.
 355          */
 356         function getSize() {
 357                 return $this->mSize;
 358         }
 359
 360         /**
 361          * Returns the title of the page associated with this entry.
 362          * @return Title
 363          */
 364         function getTitle() {
 365                 if( isset( $this->mTitle ) ) {
 366                         return $this->mTitle;
 367                 }
 368                 $dbr = wfGetDB( DB_SLAVE );
 369                 $row = $dbr->selectRow(
 370                         array( 'page', 'revision' ),
 371                         array( 'page_namespace', 'page_title' ),
 372                         array( 'page_id=rev_page',
 373                                'rev_id' => $this->mId ),
 374                         'Revision::getTitle' );
 375                 if( $row ) {
 376                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 377                                                            $row->page_title );
 378                 }
 379                 return $this->mTitle;
 380         }
 381
 382         /**
 383          * Set the title of the revision
 384          * @param Title $title
 385          */
 386         function setTitle( $title ) {
 387                 $this->mTitle = $title;
 388         }
 389
 390         /**
 391          * @return int
 392          */
 393         function getPage() {
 394                 return $this->mPage;
 395         }
 396
 397         /**
 398          * Fetch revision's user id if it's available to all users
 399          * @return int
 400          */
 401         function getUser() {
 402                 if( $this->isDeleted( self::DELETED_USER ) ) {
 403                         return 0;
 404                 } else {
 405                         return $this->mUser;
 406                 }
 407         }
 408
 409         /**
 410          * Fetch revision's user id without regard for the current user's permissions
 411          * @return string
 412          */
 413         function getRawUser() {
 414                 return $this->mUser;
 415         }
 416
 417         /**
 418          * Fetch revision's username if it's available to all users
 419          * @return string
 420          */
 421         function getUserText() {
 422                 if( $this->isDeleted( self::DELETED_USER ) ) {
 423                         return "";
 424                 } else {
 425                         return $this->mUserText;
 426                 }
 427         }
 428
 429         /**
 430          * Fetch revision's username without regard for view restrictions
 431          * @return string
 432          */
 433         function getRawUserText() {
 434                 return $this->mUserText;
 435         }
 436
 437         /**
 438          * Fetch revision comment if it's available to all users
 439          * @return string
 440          */
 441         function getComment() {
 442                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 443                         return "";
 444                 } else {
 445                         return $this->mComment;
 446                 }
 447         }
 448
 449         /**
 450          * Fetch revision comment without regard for the current user's permissions
 451          * @return string
 452          */
 453         function getRawComment() {
 454                 return $this->mComment;
 455         }
 456
 457         /**
 458          * @return bool
 459          */
 460         function isMinor() {
 461                 return (bool)$this->mMinorEdit;
 462         }
 463
 464         /**
 465          * int $field one of DELETED_* bitfield constants
 466          * @return bool
 467          */
 468         function isDeleted( $field ) {
 469                 return ($this->mDeleted & $field) == $field;
 470         }
 471
 472         /**
 473          * Fetch revision text if it's available to all users
 474          * @return string
 475          */
 476         function getText() {
 477                 if( $this->isDeleted( self::DELETED_TEXT ) ) {
 478                         return "";
 479                 } else {
 480                         return $this->getRawText();
 481                 }
 482         }
 483
 484         /**
 485          * Fetch revision text without regard for view restrictions
 486          * @return string
 487          */
 488         function getRawText() {
 489                 if( is_null( $this->mText ) ) {
 490                         // Revision text is immutable. Load on demand:
 491                         $this->mText = $this->loadText();
 492                 }
 493                 return $this->mText;
 494         }
 495
 496         /**
 497          * Fetch revision text if it's available to THIS user
 498          * @return string
 499          */
 500         function revText() {
 501                 if( !$this->userCan( self::DELETED_TEXT ) ) {
 502                         return "";
 503                 } else {
 504                         return $this->getRawText();
 505                 }
 506         }
 507
 508         /**
 509          * @return string
 510          */
 511         function getTimestamp() {
 512                 return wfTimestamp(TS_MW, $this->mTimestamp);
 513         }
 514
 515         /**
 516          * @return bool
 517          */
 518         function isCurrent() {
 519                 return $this->mCurrent;
 520         }
 521
 522         /**
 523          * @return Revision
 524          */
 525         function getPrevious() {
 526                 $prev = $this->mTitle->getPreviousRevisionID( $this->mId );
 527                 if ( $prev ) {
 528                         return Revision::newFromTitle( $this->mTitle, $prev );
 529                 } else {
 530                         return null;
 531                 }
 532         }
 533
 534         /**
 535          * @return Revision
 536          */
 537         function getNext() {
 538                 $next = $this->mTitle->getNextRevisionID( $this->mId );
 539                 if ( $next ) {
 540                         return Revision::newFromTitle( $this->mTitle, $next );
 541                 } else {
 542                         return null;
 543                 }
 544         }
 545         /**#@-*/
 546
 547         /**
 548           * Get revision text associated with an old or archive row
 549           * $row is usually an object from wfFetchRow(), both the flags and the text
 550           * field must be included
 551           * @static
 552           * @param integer $row Id of a row
 553           * @param string $prefix table prefix (default 'old_')
 554           * @return string $text|false the text requested
 555           */
 556         public static function getRevisionText( $row, $prefix = 'old_' ) {
 557                 $fname = 'Revision::getRevisionText';
 558                 wfProfileIn( $fname );
 559
 560                 # Get data
 561                 $textField = $prefix . 'text';
 562                 $flagsField = $prefix . 'flags';
 563
 564                 if( isset( $row->$flagsField ) ) {
 565                         $flags = explode( ',', $row->$flagsField );
 566                 } else {
 567                         $flags = array();
 568                 }
 569
 570                 if( isset( $row->$textField ) ) {
 571                         $text = $row->$textField;
 572                 } else {
 573                         wfProfileOut( $fname );
 574                         return false;
 575                 }
 576
 577                 # Use external methods for external objects, text in table is URL-only then
 578                 if ( in_array( 'external', $flags ) ) {
 579                         $url=$text;
 580                         @list(/* $proto */,$path)=explode('://',$url,2);
 581                         if ($path=="") {
 582                                 wfProfileOut( $fname );
 583                                 return false;
 584                         }
 585                         $text=ExternalStore::fetchFromURL($url);
 586                 }
 587
 588                 // If the text was fetched without an error, convert it
 589                 if ( $text !== false ) {
 590                         if( in_array( 'gzip', $flags ) ) {
 591                                 # Deal with optional compression of archived pages.
 592                                 # This can be done periodically via maintenance/compressOld.php, and
 593                                 # as pages are saved if $wgCompressRevisions is set.
 594                                 $text = gzinflate( $text );
 595                         }
 596
 597                         if( in_array( 'object', $flags ) ) {
 598                                 # Generic compressed storage
 599                                 $obj = unserialize( $text );
 600                                 if ( !is_object( $obj ) ) {
 601                                         // Invalid object
 602                                         wfProfileOut( $fname );
 603                                         return false;
 604                                 }
 605                                 $text = $obj->getText();
 606                         }
 607
 608                         global $wgLegacyEncoding;
 609                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 610                                 # Old revisions kept around in a legacy encoding?
 611                                 # Upconvert on demand.
 612                                 global $wgInputEncoding, $wgContLang;
 613                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding . '//IGNORE', $text );
 614                         }
 615                 }
 616                 wfProfileOut( $fname );
 617                 return $text;
 618         }
 619
 620         /**
 621          * If $wgCompressRevisions is enabled, we will compress data.
 622          * The input string is modified in place.
 623          * Return value is the flags field: contains 'gzip' if the
 624          * data is compressed, and 'utf-8' if we're saving in UTF-8
 625          * mode.
 626          *
 627          * @static
 628          * @param mixed $text reference to a text
 629          * @return string
 630          */
 631         function compressRevisionText( &$text ) {
 632                 global $wgCompressRevisions;
 633                 $flags = array();
 634
 635                 # Revisions not marked this way will be converted
 636                 # on load if $wgLegacyCharset is set in the future.
 637                 $flags[] = 'utf-8';
 638
 639                 if( $wgCompressRevisions ) {
 640                         if( function_exists( 'gzdeflate' ) ) {
 641                                 $text = gzdeflate( $text );
 642                                 $flags[] = 'gzip';
 643                         } else {
 644                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 645                         }
 646                 }
 647                 return implode( ',', $flags );
 648         }
 649
 650         /**
 651          * Insert a new revision into the database, returning the new revision ID
 652          * number on success and dies horribly on failure.
 653          *
 654          * @param Database $dbw
 655          * @return int
 656          */
 657         function insertOn( &$dbw ) {
 658                 global $wgDefaultExternalStore;
 659
 660                 $fname = 'Revision::insertOn';
 661                 wfProfileIn( $fname );
 662
 663                 $data = $this->mText;
 664                 $flags = Revision::compressRevisionText( $data );
 665
 666                 # Write to external storage if required
 667                 if ( $wgDefaultExternalStore ) {
 668                         if ( is_array( $wgDefaultExternalStore ) ) {
 669                                 // Distribute storage across multiple clusters
 670                                 $store = $wgDefaultExternalStore[mt_rand(0, count( $wgDefaultExternalStore ) - 1)];
 671                         } else {
 672                                 $store = $wgDefaultExternalStore;
 673                         }
 674                         // Store and get the URL
 675                         $data = ExternalStore::insert( $store, $data );
 676                         if ( !$data ) {
 677                                 # This should only happen in the case of a configuration error, where the external store is not valid
 678                                 throw new MWException( "Unable to store text to external storage $store" );
 679                         }
 680                         if ( $flags ) {
 681                                 $flags .= ',';
 682                         }
 683                         $flags .= 'external';
 684                 }
 685
 686                 # Record the text (or external storage URL) to the text table
 687                 if( !isset( $this->mTextId ) ) {
 688                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 689                         $dbw->insert( 'text',
 690                                 array(
 691                                         'old_id'    => $old_id,
 692                                         'old_text'  => $data,
 693                                         'old_flags' => $flags,
 694                                 ), $fname
 695                         );
 696                         $this->mTextId = $dbw->insertId();
 697                 }
 698
 699                 # Record the edit in revisions
 700                 $rev_id = isset( $this->mId )
 701                         ? $this->mId
 702                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 703                 $dbw->insert( 'revision',
 704                         array(
 705                                 'rev_id'         => $rev_id,
 706                                 'rev_page'       => $this->mPage,
 707                                 'rev_text_id'    => $this->mTextId,
 708                                 'rev_comment'    => $this->mComment,
 709                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 710                                 'rev_user'       => $this->mUser,
 711                                 'rev_user_text'  => $this->mUserText,
 712                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 713                                 'rev_deleted'    => $this->mDeleted,
 714                                 'rev_len'        => strlen($this->mText),
 715                         ), $fname
 716                 );
 717
 718                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 719                 wfProfileOut( $fname );
 720                 return $this->mId;
 721         }
 722
 723         /**
 724          * Lazy-load the revision's text.
 725          * Currently hardcoded to the 'text' table storage engine.
 726          *
 727          * @return string
 728          * @access private
 729          */
 730         function loadText() {
 731                 $fname = 'Revision::loadText';
 732                 wfProfileIn( $fname );
 733
 734                 // Caching may be beneficial for massive use of external storage
 735                 global $wgRevisionCacheExpiry, $wgMemc;
 736                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 737                 if( $wgRevisionCacheExpiry ) {
 738                         $text = $wgMemc->get( $key );
 739                         if( is_string( $text ) ) {
 740                                 wfProfileOut( $fname );
 741                                 return $text;
 742                         }
 743                 }
 744
 745                 // If we kept data for lazy extraction, use it now...
 746                 if ( isset( $this->mTextRow ) ) {
 747                         $row = $this->mTextRow;
 748                         $this->mTextRow = null;
 749                 } else {
 750                         $row = null;
 751                 }
 752
 753                 if( !$row ) {
 754                         // Text data is immutable; check slaves first.
 755                         $dbr = wfGetDB( DB_SLAVE );
 756                         $row = $dbr->selectRow( 'text',
 757                                 array( 'old_text', 'old_flags' ),
 758                                 array( 'old_id' => $this->getTextId() ),
 759                                 $fname);
 760                 }
 761
 762                 if( !$row ) {
 763                         // Possible slave lag!
 764                         $dbw = wfGetDB( DB_MASTER );
 765                         $row = $dbw->selectRow( 'text',
 766                                 array( 'old_text', 'old_flags' ),
 767                                 array( 'old_id' => $this->getTextId() ),
 768                                 $fname);
 769                 }
 770
 771                 $text = Revision::getRevisionText( $row );
 772
 773                 if( $wgRevisionCacheExpiry ) {
 774                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 775                 }
 776
 777                 wfProfileOut( $fname );
 778
 779                 return $text;
 780         }
 781
 782         /**
 783          * Create a new null-revision for insertion into a page's
 784          * history. This will not re-save the text, but simply refer
 785          * to the text from the previous version.
 786          *
 787          * Such revisions can for instance identify page rename
 788          * operations and other such meta-modifications.
 789          *
 790          * @param Database $dbw
 791          * @param int      $pageId ID number of the page to read from
 792          * @param string   $summary
 793          * @param bool     $minor
 794          * @return Revision
 795          */
 796         function newNullRevision( &$dbw, $pageId, $summary, $minor ) {
 797                 $fname = 'Revision::newNullRevision';
 798                 wfProfileIn( $fname );
 799
 800                 $current = $dbw->selectRow(
 801                         array( 'page', 'revision' ),
 802                         array( 'page_latest', 'rev_text_id' ),
 803                         array(
 804                                 'page_id' => $pageId,
 805                                 'page_latest=rev_id',
 806                                 ),
 807                         $fname );
 808
 809                 if( $current ) {
 810                         $revision = new Revision( array(
 811                                 'page'       => $pageId,
 812                                 'comment'    => $summary,
 813                                 'minor_edit' => $minor,
 814                                 'text_id'    => $current->rev_text_id,
 815                                 ) );
 816                 } else {
 817                         $revision = null;
 818                 }
 819
 820                 wfProfileOut( $fname );
 821                 return $revision;
 822         }
 823
 824         /**
 825          * Determine if the current user is allowed to view a particular
 826          * field of this revision, if it's marked as deleted.
 827          * @param int $field one of self::DELETED_TEXT,
 828          *                          self::DELETED_COMMENT,
 829          *                          self::DELETED_USER
 830          * @return bool
 831          */
 832         function userCan( $field ) {
 833                 if( ( $this->mDeleted & $field ) == $field ) {
 834                         global $wgUser;
 835                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 836                                 ? 'hiderevision'
 837                                 : 'deleterevision';
 838                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 839                         return $wgUser->isAllowed( $permission );
 840                 } else {
 841                         return true;
 842                 }
 843         }
 844
 845
 846         /**
 847          * Get rev_timestamp from rev_id, without loading the rest of the row
 848          * @param integer $id
 849          */
 850         static function getTimestampFromID( $id ) {
 851                 $dbr = wfGetDB( DB_SLAVE );
 852                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp',
 853                         array( 'rev_id' => $id ), __METHOD__ );
 854                 if ( $timestamp === false ) {
 855                         # Not in slave, try master
 856                         $dbw = wfGetDB( DB_MASTER );
 857                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp',
 858                                 array( 'rev_id' => $id ), __METHOD__ );
 859                 }
 860                 return $timestamp;
 861         }
 862
 863         static function countByPageId( $db, $id ) {
 864                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 865                         array( 'rev_page' => $id ), __METHOD__ );
 866                 if( $row ) {
 867                         return $row->revCount;
 868                 }
 869                 return 0;
 870         }
 871
 872         static function countByTitle( $db, $title ) {
 873                 $id = $title->getArticleId();
 874                 if( $id ) {
 875                         return Revision::countByPageId( $db, $id );
 876                 }
 877                 return 0;
 878         }
 879 }
 880
 881 /**
 882  * Aliases for backwards compatibility with 1.6
 883  */
 884 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 885 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 886 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 887 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );
 888
 889
 890 ?>