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