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
  15         /**
  16          * Load a page revision from a given revision ID number.
  17          * Returns null if no such revision can be found.
  18          *
  19          * @param int $id
  20          * @access public
  21          * @static
  22          */
  23         public static function newFromId( $id ) {
  24                 return Revision::newFromConds(
  25                         array( 'page_id=rev_page',
  26                                'rev_id' => intval( $id ) ) );
  27         }
  28
  29         /**
  30          * Load either the current, or a specified, revision
  31          * that's attached to a given title. If not attached
  32          * to that title, will return null.
  33          *
  34          * @param Title $title
  35          * @param int $id
  36          * @return Revision
  37          * @access public
  38          * @static
  39          */
  40         public static function newFromTitle( &$title, $id = 0 ) {
  41                 if( $id ) {
  42                         $matchId = intval( $id );
  43                 } else {
  44                         $matchId = 'page_latest';
  45                 }
  46                 return Revision::newFromConds(
  47                         array( "rev_id=$matchId",
  48                                'page_id=rev_page',
  49                                'page_namespace' => $title->getNamespace(),
  50                                'page_title'     => $title->getDBkey() ) );
  51         }
  52
  53         /**
  54          * Load a page revision from a given revision ID number.
  55          * Returns null if no such revision can be found.
  56          *
  57          * @param Database $db
  58          * @param int $id
  59          * @access public
  60          * @static
  61          */
  62         public static function loadFromId( &$db, $id ) {
  63                 return Revision::loadFromConds( $db,
  64                         array( 'page_id=rev_page',
  65                                'rev_id' => intval( $id ) ) );
  66         }
  67
  68         /**
  69          * Load either the current, or a specified, revision
  70          * that's attached to a given page. If not attached
  71          * to that page, will return null.
  72          *
  73          * @param Database $db
  74          * @param int $pageid
  75          * @param int $id
  76          * @return Revision
  77          * @access public
  78          * @static
  79          */
  80         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
  81                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  82                 if( $id ) {
  83                         $conds['rev_id']=intval($id);
  84                 } else {
  85                         $conds[]='rev_id=page_latest';
  86                 }
  87                 return Revision::loadFromConds( $db, $conds );
  88         }
  89
  90         /**
  91          * Load either the current, or a specified, revision
  92          * that's attached to a given page. If not attached
  93          * to that page, will return null.
  94          *
  95          * @param Database $db
  96          * @param Title $title
  97          * @param int $id
  98          * @return Revision
  99          * @access public
 100          * @static
 101          */
 102         public static function loadFromTitle( &$db, $title, $id = 0 ) {
 103                 if( $id ) {
 104                         $matchId = intval( $id );
 105                 } else {
 106                         $matchId = 'page_latest';
 107                 }
 108                 return Revision::loadFromConds(
 109                         $db,
 110                         array( "rev_id=$matchId",
 111                                'page_id=rev_page',
 112                                'page_namespace' => $title->getNamespace(),
 113                                'page_title'     => $title->getDBkey() ) );
 114         }
 115
 116         /**
 117          * Load the revision for the given title with the given timestamp.
 118          * WARNING: Timestamps may in some circumstances not be unique,
 119          * so this isn't the best key to use.
 120          *
 121          * @param Database $db
 122          * @param Title $title
 123          * @param string $timestamp
 124          * @return Revision
 125          * @access public
 126          * @static
 127          */
 128         public static function loadFromTimestamp( &$db, &$title, $timestamp ) {
 129                 return Revision::loadFromConds(
 130                         $db,
 131                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 132                                'page_id=rev_page',
 133                                'page_namespace' => $title->getNamespace(),
 134                                'page_title'     => $title->getDBkey() ) );
 135         }
 136
 137         /**
 138          * Given a set of conditions, fetch a revision.
 139          *
 140          * @param array $conditions
 141          * @return Revision
 142          * @access private
 143          * @static
 144          */
 145         private static function newFromConds( $conditions ) {
 146                 $db = wfGetDB( DB_SLAVE );
 147                 $row = Revision::loadFromConds( $db, $conditions );
 148                 if( is_null( $row ) ) {
 149                         $dbw = wfGetDB( DB_MASTER );
 150                         $row = Revision::loadFromConds( $dbw, $conditions );
 151                 }
 152                 return $row;
 153         }
 154
 155         /**
 156          * Given a set of conditions, fetch a revision from
 157          * the given database connection.
 158          *
 159          * @param Database $db
 160          * @param array $conditions
 161          * @return Revision
 162          * @access private
 163          * @static
 164          */
 165         private static function loadFromConds( $db, $conditions ) {
 166                 $res = Revision::fetchFromConds( $db, $conditions );
 167                 if( $res ) {
 168                         $row = $res->fetchObject();
 169                         $res->free();
 170                         if( $row ) {
 171                                 $ret = new Revision( $row );
 172                                 return $ret;
 173                         }
 174                 }
 175                 $ret = null;
 176                 return $ret;
 177         }
 178
 179         /**
 180          * Return a wrapper for a series of database rows to
 181          * fetch all of a given page's revisions in turn.
 182          * Each row can be fed to the constructor to get objects.
 183          *
 184          * @param Title $title
 185          * @return ResultWrapper
 186          * @access public
 187          * @static
 188          */
 189         public static function fetchAllRevisions( &$title ) {
 190                 return Revision::fetchFromConds(
 191                         wfGetDB( DB_SLAVE ),
 192                         array( 'page_namespace' => $title->getNamespace(),
 193                                'page_title'     => $title->getDBkey(),
 194                                'page_id=rev_page' ) );
 195         }
 196
 197         /**
 198          * Return a wrapper for a series of database rows to
 199          * fetch all of a given page's revisions in turn.
 200          * Each row can be fed to the constructor to get objects.
 201          *
 202          * @param Title $title
 203          * @return ResultWrapper
 204          * @access public
 205          * @static
 206          */
 207         public static function fetchRevision( &$title ) {
 208                 return Revision::fetchFromConds(
 209                         wfGetDB( DB_SLAVE ),
 210                         array( 'rev_id=page_latest',
 211                                'page_namespace' => $title->getNamespace(),
 212                                'page_title'     => $title->getDBkey(),
 213                                'page_id=rev_page' ) );
 214         }
 215
 216         /**
 217          * Given a set of conditions, return a ResultWrapper
 218          * which will return matching database rows with the
 219          * fields necessary to build Revision objects.
 220          *
 221          * @param Database $db
 222          * @param array $conditions
 223          * @return ResultWrapper
 224          * @access private
 225          * @static
 226          */
 227         private static function fetchFromConds( $db, $conditions ) {
 228                 $fields = self::selectFields();
 229                 $fields[] = 'page_namespace';
 230                 $fields[] = 'page_title';
 231                 $fields[] = 'page_latest';
 232                 $res = $db->select(
 233                         array( 'page', 'revision' ),
 234                         $fields,
 235                         $conditions,
 236                         'Revision::fetchRow',
 237                         array( 'LIMIT' => 1 ) );
 238                 $ret = $db->resultObject( $res );
 239                 return $ret;
 240         }
 241
 242         /**
 243          * Return the list of revision fields that should be selected to create
 244          * a new revision.
 245          */
 246         static function selectFields() {
 247                 return array(
 248                         'rev_id',
 249                         'rev_page',
 250                         'rev_text_id',
 251                         'rev_timestamp',
 252                         'rev_comment',
 253                         'rev_user_text,'.
 254                         'rev_user',
 255                         'rev_minor_edit',
 256                         'rev_deleted',
 257                         'rev_len',
 258                         'rev_parent_id'
 259                 );
 260         }
 261
 262         /**
 263          * @param object $row
 264          * @access private
 265          */
 266         function Revision( $row ) {
 267                 if( is_object( $row ) ) {
 268                         $this->mId        = intval( $row->rev_id );
 269                         $this->mPage      = intval( $row->rev_page );
 270                         $this->mTextId    = intval( $row->rev_text_id );
 271                         $this->mComment   =         $row->rev_comment;
 272                         $this->mUserText  =         $row->rev_user_text;
 273                         $this->mUser      = intval( $row->rev_user );
 274                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 275                         $this->mTimestamp =         $row->rev_timestamp;
 276                         $this->mDeleted   = intval( $row->rev_deleted );
 277                         $this->mParentId  = intval( $row->rev_parent_id );
 278
 279                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 280                                 $this->mSize = null;
 281                         else
 282                                 $this->mSize = intval( $row->rev_len );
 283
 284                         if( isset( $row->page_latest ) ) {
 285                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 286                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 287                                                                       $row->page_title );
 288                         } else {
 289                                 $this->mCurrent = false;
 290                                 $this->mTitle = null;
 291                         }
 292
 293                         // Lazy extraction...
 294                         $this->mText      = null;
 295                         if( isset( $row->old_text ) ) {
 296                                 $this->mTextRow = $row;
 297                         } else {
 298                                 // 'text' table row entry will be lazy-loaded
 299                                 $this->mTextRow = null;
 300                         }
 301                 } elseif( is_array( $row ) ) {
 302                         // Build a new revision to be saved...
 303                         global $wgUser;
 304
 305                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 306                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 307                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 308                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 309                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 310                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 311                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 312                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 313                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 314                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : 0;
 315
 316                         // Enforce spacing trimming on supplied text
 317                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 318                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 319                         $this->mTextRow   = null;
 320
 321                         $this->mTitle     = null; # Load on demand if needed
 322                         $this->mCurrent   = false;
 323                         # If we still have no len_size, see it we have the text to figure it out
 324                         if ( !$this->mSize )
 325                                 $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 326                 } else {
 327                         throw new MWException( 'Revision constructor passed invalid row format.' );
 328                 }
 329         }
 330
 331         /**#@+
 332          * @access public
 333          */
 334
 335         /**
 336          * Get revision ID
 337          * @return int
 338          */
 339         public function getId() {
 340                 return $this->mId;
 341         }
 342
 343         /**
 344          * Get text row ID
 345          * @return int
 346          */
 347         public function getTextId() {
 348                 return $this->mTextId;
 349         }
 350
 351         /**
 352          * Get parent revision ID (the original previous page revision)
 353          * @return int
 354          */
 355         public function getParentId() {
 356                 return $this->mParentId;
 357         }
 358
 359         /**
 360          * Returns the length of the text in this revision, or null if unknown.
 361          * @return int
 362          */
 363         public function getSize() {
 364                 return $this->mSize;
 365         }
 366
 367         /**
 368          * Returns the title of the page associated with this entry.
 369          * @return Title
 370          */
 371         public function getTitle() {
 372                 if( isset( $this->mTitle ) ) {
 373                         return $this->mTitle;
 374                 }
 375                 $dbr = wfGetDB( DB_SLAVE );
 376                 $row = $dbr->selectRow(
 377                         array( 'page', 'revision' ),
 378                         array( 'page_namespace', 'page_title' ),
 379                         array( 'page_id=rev_page',
 380                                'rev_id' => $this->mId ),
 381                         'Revision::getTitle' );
 382                 if( $row ) {
 383                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 384                                                            $row->page_title );
 385                 }
 386                 return $this->mTitle;
 387         }
 388
 389         /**
 390          * Set the title of the revision
 391          * @param Title $title
 392          */
 393         public function setTitle( $title ) {
 394                 $this->mTitle = $title;
 395         }
 396
 397         /**
 398          * Get the page ID
 399          * @return int
 400          */
 401         public function getPage() {
 402                 return $this->mPage;
 403         }
 404
 405         /**
 406          * Fetch revision's user id if it's available to all users
 407          * @return int
 408          */
 409         public function getUser() {
 410                 if( $this->isDeleted( self::DELETED_USER ) ) {
 411                         return 0;
 412                 } else {
 413                         return $this->mUser;
 414                 }
 415         }
 416
 417         /**
 418          * Fetch revision's user id without regard for the current user's permissions
 419          * @return string
 420          */
 421         public function getRawUser() {
 422                 return $this->mUser;
 423         }
 424
 425         /**
 426          * Fetch revision's username if it's available to all users
 427          * @return string
 428          */
 429         public function getUserText() {
 430                 if( $this->isDeleted( self::DELETED_USER ) ) {
 431                         return "";
 432                 } else {
 433                         return $this->mUserText;
 434                 }
 435         }
 436
 437         /**
 438          * Fetch revision's username without regard for view restrictions
 439          * @return string
 440          */
 441         public function getRawUserText() {
 442                 return $this->mUserText;
 443         }
 444
 445         /**
 446          * Fetch revision comment if it's available to all users
 447          * @return string
 448          */
 449         function getComment() {
 450                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 451                         return "";
 452                 } else {
 453                         return $this->mComment;
 454                 }
 455         }
 456
 457         /**
 458          * Fetch revision comment without regard for the current user's permissions
 459          * @return string
 460          */
 461         public function getRawComment() {
 462                 return $this->mComment;
 463         }
 464
 465         /**
 466          * @return bool
 467          */
 468         public function isMinor() {
 469                 return (bool)$this->mMinorEdit;
 470         }
 471
 472         /**
 473          * int $field one of DELETED_* bitfield constants
 474          * @return bool
 475          */
 476         public function isDeleted( $field ) {
 477                 return ($this->mDeleted & $field) == $field;
 478         }
 479
 480         /**
 481          * Fetch revision text if it's available to all users
 482          * @return string
 483          */
 484         public function getText() {
 485                 if( $this->isDeleted( self::DELETED_TEXT ) ) {
 486                         return "";
 487                 } else {
 488                         return $this->getRawText();
 489                 }
 490         }
 491
 492         /**
 493          * Fetch revision text without regard for view restrictions
 494          * @return string
 495          */
 496         public function getRawText() {
 497                 if( is_null( $this->mText ) ) {
 498                         // Revision text is immutable. Load on demand:
 499                         $this->mText = $this->loadText();
 500                 }
 501                 return $this->mText;
 502         }
 503
 504         /**
 505          * Fetch revision text if it's available to THIS user
 506          * @return string
 507          */
 508         public function revText() {
 509                 if( !$this->userCan( self::DELETED_TEXT ) ) {
 510                         return "";
 511                 } else {
 512                         return $this->getRawText();
 513                 }
 514         }
 515
 516         /**
 517          * @return string
 518          */
 519         public function getTimestamp() {
 520                 return wfTimestamp(TS_MW, $this->mTimestamp);
 521         }
 522
 523         /**
 524          * @return bool
 525          */
 526         public function isCurrent() {
 527                 return $this->mCurrent;
 528         }
 529
 530         /**
 531          * Get previous revision for this title
 532          * @return Revision
 533          */
 534         public function getPrevious() {
 535                 $prev = $this->mTitle->getPreviousRevisionID( $this->mId );
 536                 if( $prev ) {
 537                         return Revision::newFromTitle( $this->mTitle, $prev );
 538                 } else {
 539                         return null;
 540                 }
 541         }
 542
 543         /**
 544          * @return Revision
 545          */
 546         public function getNext() {
 547                 $next = $this->mTitle->getNextRevisionID( $this->mId );
 548                 if ( $next ) {
 549                         return Revision::newFromTitle( $this->mTitle, $next );
 550                 } else {
 551                         return null;
 552                 }
 553         }
 554
 555         /**
 556          * Get previous revision Id for this page_id
 557          * This is used to populate rev_parent_id on save
 558          * @param Database $db
 559          * @return int
 560          */
 561         private function getPreviousRevisionId( $db ) {
 562                 if( is_null($this->mPage) ) {
 563                         return 0;
 564                 }
 565                 # Use page_latest if ID is not given
 566                 if( !$this->mId ) {
 567                         $revID = $db->selectField( 'page', 'page_latest',
 568                                 array( 'page_id' => $this->mPage ),
 569                                 __METHOD__ );
 570                 } else {
 571                         $revID = $this->mId;
 572                 }
 573                 if( !$revID ) {
 574                         return 0;
 575                 }
 576                 $prevId = $db->selectField( 'revision', 'rev_id',
 577                         array( 'rev_page' => $this->mPage, 'rev_id < ' . $revID ),
 578                         __METHOD__,
 579                         array( 'ORDER BY' => 'rev_id DESC' ) );
 580                 # Always return an integer
 581                 return intval($prevId);
 582         }
 583
 584         /**
 585           * Get revision text associated with an old or archive row
 586           * $row is usually an object from wfFetchRow(), both the flags and the text
 587           * field must be included
 588           *
 589           * @param integer $row Id of a row
 590           * @param string $prefix table prefix (default 'old_')
 591           * @return string $text|false the text requested
 592           */
 593         public static function getRevisionText( $row, $prefix = 'old_' ) {
 594                 wfProfileIn( __METHOD__ );
 595
 596                 # Get data
 597                 $textField = $prefix . 'text';
 598                 $flagsField = $prefix . 'flags';
 599
 600                 if( isset( $row->$flagsField ) ) {
 601                         $flags = explode( ',', $row->$flagsField );
 602                 } else {
 603                         $flags = array();
 604                 }
 605
 606                 if( isset( $row->$textField ) ) {
 607                         $text = $row->$textField;
 608                 } else {
 609                         wfProfileOut( __METHOD__ );
 610                         return false;
 611                 }
 612
 613                 # Use external methods for external objects, text in table is URL-only then
 614                 if ( in_array( 'external', $flags ) ) {
 615                         $url=$text;
 616                         @list(/* $proto */,$path)=explode('://',$url,2);
 617                         if ($path=="") {
 618                                 wfProfileOut( __METHOD__ );
 619                                 return false;
 620                         }
 621                         $text=ExternalStore::fetchFromURL($url);
 622                 }
 623
 624                 // If the text was fetched without an error, convert it
 625                 if ( $text !== false ) {
 626                         if( in_array( 'gzip', $flags ) ) {
 627                                 # Deal with optional compression of archived pages.
 628                                 # This can be done periodically via maintenance/compressOld.php, and
 629                                 # as pages are saved if $wgCompressRevisions is set.
 630                                 $text = gzinflate( $text );
 631                         }
 632
 633                         if( in_array( 'object', $flags ) ) {
 634                                 # Generic compressed storage
 635                                 $obj = unserialize( $text );
 636                                 if ( !is_object( $obj ) ) {
 637                                         // Invalid object
 638                                         wfProfileOut( __METHOD__ );
 639                                         return false;
 640                                 }
 641                                 $text = $obj->getText();
 642                         }
 643
 644                         global $wgLegacyEncoding;
 645                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 646                                 # Old revisions kept around in a legacy encoding?
 647                                 # Upconvert on demand.
 648                                 global $wgInputEncoding, $wgContLang;
 649                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 650                         }
 651                 }
 652                 wfProfileOut( __METHOD__ );
 653                 return $text;
 654         }
 655
 656         /**
 657          * If $wgCompressRevisions is enabled, we will compress data.
 658          * The input string is modified in place.
 659          * Return value is the flags field: contains 'gzip' if the
 660          * data is compressed, and 'utf-8' if we're saving in UTF-8
 661          * mode.
 662          *
 663          * @param mixed $text reference to a text
 664          * @return string
 665          */
 666         public static function compressRevisionText( &$text ) {
 667                 global $wgCompressRevisions;
 668                 $flags = array();
 669
 670                 # Revisions not marked this way will be converted
 671                 # on load if $wgLegacyCharset is set in the future.
 672                 $flags[] = 'utf-8';
 673
 674                 if( $wgCompressRevisions ) {
 675                         if( function_exists( 'gzdeflate' ) ) {
 676                                 $text = gzdeflate( $text );
 677                                 $flags[] = 'gzip';
 678                         } else {
 679                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 680                         }
 681                 }
 682                 return implode( ',', $flags );
 683         }
 684
 685         /**
 686          * Insert a new revision into the database, returning the new revision ID
 687          * number on success and dies horribly on failure.
 688          *
 689          * @param Database $dbw
 690          * @return int
 691          */
 692         public function insertOn( &$dbw ) {
 693                 global $wgDefaultExternalStore;
 694
 695                 wfProfileIn( __METHOD__ );
 696
 697                 $data = $this->mText;
 698                 $flags = Revision::compressRevisionText( $data );
 699
 700                 # Write to external storage if required
 701                 if ( $wgDefaultExternalStore ) {
 702                         if ( is_array( $wgDefaultExternalStore ) ) {
 703                                 // Distribute storage across multiple clusters
 704                                 $store = $wgDefaultExternalStore[mt_rand(0, count( $wgDefaultExternalStore ) - 1)];
 705                         } else {
 706                                 $store = $wgDefaultExternalStore;
 707                         }
 708                         // Store and get the URL
 709                         $data = ExternalStore::insert( $store, $data );
 710                         if ( !$data ) {
 711                                 # This should only happen in the case of a configuration error, where the external store is not valid
 712                                 throw new MWException( "Unable to store text to external storage $store" );
 713                         }
 714                         if ( $flags ) {
 715                                 $flags .= ',';
 716                         }
 717                         $flags .= 'external';
 718                 }
 719
 720                 # Record the text (or external storage URL) to the text table
 721                 if( !isset( $this->mTextId ) ) {
 722                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 723                         $dbw->insert( 'text',
 724                                 array(
 725                                         'old_id'    => $old_id,
 726                                         'old_text'  => $data,
 727                                         'old_flags' => $flags,
 728                                 ), __METHOD__
 729                         );
 730                         $this->mTextId = $dbw->insertId();
 731                 }
 732
 733                 # Record the edit in revisions
 734                 $rev_id = isset( $this->mId )
 735                         ? $this->mId
 736                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 737                 $dbw->insert( 'revision',
 738                         array(
 739                                 'rev_id'         => $rev_id,
 740                                 'rev_page'       => $this->mPage,
 741                                 'rev_text_id'    => $this->mTextId,
 742                                 'rev_comment'    => $this->mComment,
 743                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 744                                 'rev_user'       => $this->mUser,
 745                                 'rev_user_text'  => $this->mUserText,
 746                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 747                                 'rev_deleted'    => $this->mDeleted,
 748                                 'rev_len'            => $this->mSize,
 749                                 'rev_parent_id'  => $this->mParentId ? $this->mParentId : $this->getPreviousRevisionId( $dbw )
 750                         ), __METHOD__
 751                 );
 752
 753                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 754                 wfProfileOut( __METHOD__ );
 755                 return $this->mId;
 756         }
 757
 758         /**
 759          * Lazy-load the revision's text.
 760          * Currently hardcoded to the 'text' table storage engine.
 761          *
 762          * @return string
 763          */
 764         private function loadText() {
 765                 wfProfileIn( __METHOD__ );
 766
 767                 // Caching may be beneficial for massive use of external storage
 768                 global $wgRevisionCacheExpiry, $wgMemc;
 769                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 770                 if( $wgRevisionCacheExpiry ) {
 771                         $text = $wgMemc->get( $key );
 772                         if( is_string( $text ) ) {
 773                                 wfProfileOut( __METHOD__ );
 774                                 return $text;
 775                         }
 776                 }
 777
 778                 // If we kept data for lazy extraction, use it now...
 779                 if ( isset( $this->mTextRow ) ) {
 780                         $row = $this->mTextRow;
 781                         $this->mTextRow = null;
 782                 } else {
 783                         $row = null;
 784                 }
 785
 786                 if( !$row ) {
 787                         // Text data is immutable; check slaves first.
 788                         $dbr = wfGetDB( DB_SLAVE );
 789                         $row = $dbr->selectRow( 'text',
 790                                 array( 'old_text', 'old_flags' ),
 791                                 array( 'old_id' => $this->getTextId() ),
 792                                 __METHOD__ );
 793                 }
 794
 795                 if( !$row ) {
 796                         // Possible slave lag!
 797                         $dbw = wfGetDB( DB_MASTER );
 798                         $row = $dbw->selectRow( 'text',
 799                                 array( 'old_text', 'old_flags' ),
 800                                 array( 'old_id' => $this->getTextId() ),
 801                                 __METHOD__ );
 802                 }
 803
 804                 $text = self::getRevisionText( $row );
 805
 806                 if( $wgRevisionCacheExpiry ) {
 807                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 808                 }
 809
 810                 wfProfileOut( __METHOD__ );
 811
 812                 return $text;
 813         }
 814
 815         /**
 816          * Create a new null-revision for insertion into a page's
 817          * history. This will not re-save the text, but simply refer
 818          * to the text from the previous version.
 819          *
 820          * Such revisions can for instance identify page rename
 821          * operations and other such meta-modifications.
 822          *
 823          * @param Database $dbw
 824          * @param int      $pageId ID number of the page to read from
 825          * @param string   $summary
 826          * @param bool     $minor
 827          * @return Revision
 828          */
 829         public static function newNullRevision( &$dbw, $pageId, $summary, $minor ) {
 830                 wfProfileIn( __METHOD__ );
 831
 832                 $current = $dbw->selectRow(
 833                         array( 'page', 'revision' ),
 834                         array( 'page_latest', 'rev_text_id' ),
 835                         array(
 836                                 'page_id' => $pageId,
 837                                 'page_latest=rev_id',
 838                                 ),
 839                         __METHOD__ );
 840
 841                 if( $current ) {
 842                         $revision = new Revision( array(
 843                                 'page'       => $pageId,
 844                                 'comment'    => $summary,
 845                                 'minor_edit' => $minor,
 846                                 'text_id'    => $current->rev_text_id,
 847                                 'parent_id'  => $current->page_latest
 848                                 ) );
 849                 } else {
 850                         $revision = null;
 851                 }
 852
 853                 wfProfileOut( __METHOD__ );
 854                 return $revision;
 855         }
 856
 857         /**
 858          * Determine if the current user is allowed to view a particular
 859          * field of this revision, if it's marked as deleted.
 860          * @param int $field one of self::DELETED_TEXT,
 861          *                          self::DELETED_COMMENT,
 862          *                          self::DELETED_USER
 863          * @return bool
 864          */
 865         public function userCan( $field ) {
 866                 if( ( $this->mDeleted & $field ) == $field ) {
 867                         global $wgUser;
 868                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 869                                 ? 'hiderevision'
 870                                 : 'deleterevision';
 871                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 872                         return $wgUser->isAllowed( $permission );
 873                 } else {
 874                         return true;
 875                 }
 876         }
 877
 878
 879         /**
 880          * Get rev_timestamp from rev_id, without loading the rest of the row
 881          * @param integer $id
 882          */
 883         static function getTimestampFromID( $id ) {
 884                 $dbr = wfGetDB( DB_SLAVE );
 885                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp',
 886                         array( 'rev_id' => $id ), __METHOD__ );
 887                 if ( $timestamp === false ) {
 888                         # Not in slave, try master
 889                         $dbw = wfGetDB( DB_MASTER );
 890                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp',
 891                                 array( 'rev_id' => $id ), __METHOD__ );
 892                 }
 893                 return $timestamp;
 894         }
 895
 896         /**
 897          * Get count of revisions per page...not very efficient
 898          * @param Database $db
 899          * @param int $id, page id
 900          */
 901         static function countByPageId( $db, $id ) {
 902                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 903                         array( 'rev_page' => $id ), __METHOD__ );
 904                 if( $row ) {
 905                         return $row->revCount;
 906                 }
 907                 return 0;
 908         }
 909
 910         /**
 911          * Get count of revisions per page...not very efficient
 912          * @param Database $db
 913          * @param Title $title
 914          */
 915         static function countByTitle( $db, $title ) {
 916                 $id = $title->getArticleId();
 917                 if( $id ) {
 918                         return Revision::countByPageId( $db, $id );
 919                 }
 920                 return 0;
 921         }
 922 }
 923
 924 /**
 925  * Aliases for backwards compatibility with 1.6
 926  */
 927 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 928 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 929 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 930 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );
 931
 932
 933