includes/Revision.php

   1 <?php
   2 /**
   3  * @todo document
   4  * @file
   5  */
   6
   7 /**
   8  * @todo document
   9  */
  10 class Revision {
  11         const DELETED_TEXT = 1;
  12         const DELETED_COMMENT = 2;
  13         const DELETED_USER = 4;
  14         const DELETED_RESTRICTED = 8;
  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          */
  39         public static function newFromTitle( $title, $id = 0 ) {
  40                 if( $id ) {
  41                         $matchId = intval( $id );
  42                 } else {
  43                         $matchId = 'page_latest';
  44                 }
  45                 return Revision::newFromConds(
  46                         array( "rev_id=$matchId",
  47                                'page_id=rev_page',
  48                                'page_namespace' => $title->getNamespace(),
  49                                'page_title'     => $title->getDBkey() ) );
  50         }
  51
  52         /**
  53          * Load a page revision from a given revision ID number.
  54          * Returns null if no such revision can be found.
  55          *
  56          * @param Database $db
  57          * @param int $id
  58          * @access public
  59          * @static
  60          */
  61         public static function loadFromId( $db, $id ) {
  62                 return Revision::loadFromConds( $db,
  63                         array( 'page_id=rev_page',
  64                                'rev_id' => intval( $id ) ) );
  65         }
  66
  67         /**
  68          * Load either the current, or a specified, revision
  69          * that's attached to a given page. If not attached
  70          * to that page, will return null.
  71          *
  72          * @param Database $db
  73          * @param int $pageid
  74          * @param int $id
  75          * @return Revision
  76          * @access public
  77          * @static
  78          */
  79         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
  80                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  81                 if( $id ) {
  82                         $conds['rev_id']=intval($id);
  83                 } else {
  84                         $conds[]='rev_id=page_latest';
  85                 }
  86                 return Revision::loadFromConds( $db, $conds );
  87         }
  88
  89         /**
  90          * Load either the current, or a specified, revision
  91          * that's attached to a given page. If not attached
  92          * to that page, will return null.
  93          *
  94          * @param Database $db
  95          * @param Title $title
  96          * @param int $id
  97          * @return Revision
  98          * @access public
  99          * @static
 100          */
 101         public static function loadFromTitle( $db, $title, $id = 0 ) {
 102                 if( $id ) {
 103                         $matchId = intval( $id );
 104                 } else {
 105                         $matchId = 'page_latest';
 106                 }
 107                 return Revision::loadFromConds(
 108                         $db,
 109                         array( "rev_id=$matchId",
 110                                'page_id=rev_page',
 111                                'page_namespace' => $title->getNamespace(),
 112                                'page_title'     => $title->getDBkey() ) );
 113         }
 114
 115         /**
 116          * Load the revision for the given title with the given timestamp.
 117          * WARNING: Timestamps may in some circumstances not be unique,
 118          * so this isn't the best key to use.
 119          *
 120          * @param Database $db
 121          * @param Title $title
 122          * @param string $timestamp
 123          * @return Revision
 124          * @access public
 125          * @static
 126          */
 127         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 128                 return Revision::loadFromConds(
 129                         $db,
 130                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 131                                'page_id=rev_page',
 132                                'page_namespace' => $title->getNamespace(),
 133                                'page_title'     => $title->getDBkey() ) );
 134         }
 135
 136         /**
 137          * Given a set of conditions, fetch a revision.
 138          *
 139          * @param array $conditions
 140          * @return Revision
 141          * @access private
 142          * @static
 143          */
 144         private static function newFromConds( $conditions ) {
 145                 $db = wfGetDB( DB_SLAVE );
 146                 $row = Revision::loadFromConds( $db, $conditions );
 147                 if( is_null( $row ) ) {
 148                         $dbw = wfGetDB( DB_MASTER );
 149                         $row = Revision::loadFromConds( $dbw, $conditions );
 150                 }
 151                 return $row;
 152         }
 153
 154         /**
 155          * Given a set of conditions, fetch a revision from
 156          * the given database connection.
 157          *
 158          * @param Database $db
 159          * @param array $conditions
 160          * @return Revision
 161          * @access private
 162          * @static
 163          */
 164         private static function loadFromConds( $db, $conditions ) {
 165                 $res = Revision::fetchFromConds( $db, $conditions );
 166                 if( $res ) {
 167                         $row = $res->fetchObject();
 168                         $res->free();
 169                         if( $row ) {
 170                                 $ret = new Revision( $row );
 171                                 return $ret;
 172                         }
 173                 }
 174                 $ret = null;
 175                 return $ret;
 176         }
 177
 178         /**
 179          * Return a wrapper for a series of database rows to
 180          * fetch all of a given page's revisions in turn.
 181          * Each row can be fed to the constructor to get objects.
 182          *
 183          * @param Title $title
 184          * @return ResultWrapper
 185          * @access public
 186          * @static
 187          */
 188         public static function fetchAllRevisions( $title ) {
 189                 return Revision::fetchFromConds(
 190                         wfGetDB( DB_SLAVE ),
 191                         array( 'page_namespace' => $title->getNamespace(),
 192                                'page_title'     => $title->getDBkey(),
 193                                'page_id=rev_page' ) );
 194         }
 195
 196         /**
 197          * Return a wrapper for a series of database rows to
 198          * fetch all of a given page's revisions in turn.
 199          * Each row can be fed to the constructor to get objects.
 200          *
 201          * @param Title $title
 202          * @return ResultWrapper
 203          * @access public
 204          * @static
 205          */
 206         public static function fetchRevision( $title ) {
 207                 return Revision::fetchFromConds(
 208                         wfGetDB( DB_SLAVE ),
 209                         array( 'rev_id=page_latest',
 210                                'page_namespace' => $title->getNamespace(),
 211                                'page_title'     => $title->getDBkey(),
 212                                'page_id=rev_page' ) );
 213         }
 214
 215         /**
 216          * Given a set of conditions, return a ResultWrapper
 217          * which will return matching database rows with the
 218          * fields necessary to build Revision objects.
 219          *
 220          * @param Database $db
 221          * @param array $conditions
 222          * @return ResultWrapper
 223          * @access private
 224          * @static
 225          */
 226         private static function fetchFromConds( $db, $conditions ) {
 227                 $fields = self::selectFields();
 228                 $fields[] = 'page_namespace';
 229                 $fields[] = 'page_title';
 230                 $fields[] = 'page_latest';
 231                 $res = $db->select(
 232                         array( 'page', 'revision' ),
 233                         $fields,
 234                         $conditions,
 235                         'Revision::fetchRow',
 236                         array( 'LIMIT' => 1 ) );
 237                 $ret = $db->resultObject( $res );
 238                 return $ret;
 239         }
 240
 241         /**
 242          * Return the list of revision fields that should be selected to create
 243          * a new revision.
 244          */
 245         static function selectFields() {
 246                 return array(
 247                         'rev_id',
 248                         'rev_page',
 249                         'rev_text_id',
 250                         'rev_timestamp',
 251                         'rev_comment',
 252                         'rev_user_text,'.
 253                         'rev_user',
 254                         'rev_minor_edit',
 255                         'rev_deleted',
 256                         'rev_len',
 257                         'rev_parent_id'
 258                 );
 259         }
 260
 261         /**
 262          * Return the list of text fields that should be selected to read the
 263          * revision text
 264          */
 265         static function selectTextFields() {
 266                 return array(
 267                         'old_text',
 268                         'old_flags'
 269                 );
 270         }
 271         /**
 272          * Return the list of page fields that should be selected from page table
 273          */
 274         static function selectPageFields() {
 275                 return array(
 276                         'page_namespace',
 277                         'page_title',
 278                         'page_latest'
 279                 );
 280         }
 281
 282         /**
 283          * @param object $row
 284          * @access private
 285          */
 286         function Revision( $row ) {
 287                 if( is_object( $row ) ) {
 288                         $this->mId        = intval( $row->rev_id );
 289                         $this->mPage      = intval( $row->rev_page );
 290                         $this->mTextId    = intval( $row->rev_text_id );
 291                         $this->mComment   =         $row->rev_comment;
 292                         $this->mUserText  =         $row->rev_user_text;
 293                         $this->mUser      = intval( $row->rev_user );
 294                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 295                         $this->mTimestamp =         $row->rev_timestamp;
 296                         $this->mDeleted   = intval( $row->rev_deleted );
 297
 298                         if( !isset( $row->rev_parent_id ) )
 299                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 300                         else
 301                                 $this->mParentId  = intval( $row->rev_parent_id );
 302
 303                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 304                                 $this->mSize = null;
 305                         else
 306                                 $this->mSize = intval( $row->rev_len );
 307
 308                         if( isset( $row->page_latest ) ) {
 309                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 310                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 311                                                                       $row->page_title );
 312                         } else {
 313                                 $this->mCurrent = false;
 314                                 $this->mTitle = null;
 315                         }
 316
 317                         // Lazy extraction...
 318                         $this->mText      = null;
 319                         if( isset( $row->old_text ) ) {
 320                                 $this->mTextRow = $row;
 321                         } else {
 322                                 // 'text' table row entry will be lazy-loaded
 323                                 $this->mTextRow = null;
 324                         }
 325                 } elseif( is_array( $row ) ) {
 326                         // Build a new revision to be saved...
 327                         global $wgUser;
 328
 329                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 330                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 331                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 332                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 333                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 334                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 335                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 336                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 337                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 338                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 339
 340                         // Enforce spacing trimming on supplied text
 341                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 342                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 343                         $this->mTextRow   = null;
 344
 345                         $this->mTitle     = null; # Load on demand if needed
 346                         $this->mCurrent   = false;
 347                         # If we still have no len_size, see it we have the text to figure it out
 348                         if ( !$this->mSize )
 349                                 $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 350                 } else {
 351                         throw new MWException( 'Revision constructor passed invalid row format.' );
 352                 }
 353         }
 354
 355         /**#@+
 356          * @access public
 357          */
 358
 359         /**
 360          * Get revision ID
 361          * @return int
 362          */
 363         public function getId() {
 364                 return $this->mId;
 365         }
 366
 367         /**
 368          * Get text row ID
 369          * @return int
 370          */
 371         public function getTextId() {
 372                 return $this->mTextId;
 373         }
 374
 375         /**
 376          * Get parent revision ID (the original previous page revision)
 377          * @return int
 378          */
 379         public function getParentId() {
 380                 return $this->mParentId;
 381         }
 382
 383         /**
 384          * Returns the length of the text in this revision, or null if unknown.
 385          * @return int
 386          */
 387         public function getSize() {
 388                 return $this->mSize;
 389         }
 390
 391         /**
 392          * Returns the title of the page associated with this entry.
 393          * @return Title
 394          */
 395         public function getTitle() {
 396                 if( isset( $this->mTitle ) ) {
 397                         return $this->mTitle;
 398                 }
 399                 $dbr = wfGetDB( DB_SLAVE );
 400                 $row = $dbr->selectRow(
 401                         array( 'page', 'revision' ),
 402                         array( 'page_namespace', 'page_title' ),
 403                         array( 'page_id=rev_page',
 404                                'rev_id' => $this->mId ),
 405                         'Revision::getTitle' );
 406                 if( $row ) {
 407                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 408                                                           $row->page_title );
 409                 }
 410                 return $this->mTitle;
 411         }
 412
 413         /**
 414          * Set the title of the revision
 415          * @param Title $title
 416          */
 417         public function setTitle( $title ) {
 418                 $this->mTitle = $title;
 419         }
 420
 421         /**
 422          * Get the page ID
 423          * @return int
 424          */
 425         public function getPage() {
 426                 return $this->mPage;
 427         }
 428
 429         /**
 430          * Fetch revision's user id if it's available to all users
 431          * @return int
 432          */
 433         public function getUser() {
 434                 if( $this->isDeleted( self::DELETED_USER ) ) {
 435                         return 0;
 436                 } else {
 437                         return $this->mUser;
 438                 }
 439         }
 440
 441         /**
 442          * Fetch revision's user id without regard for the current user's permissions
 443          * @return string
 444          */
 445         public function getRawUser() {
 446                 return $this->mUser;
 447         }
 448
 449         /**
 450          * Fetch revision's username if it's available to all users
 451          * @return string
 452          */
 453         public function getUserText() {
 454                 if( $this->isDeleted( self::DELETED_USER ) ) {
 455                         return "";
 456                 } else {
 457                         return $this->mUserText;
 458                 }
 459         }
 460
 461         /**
 462          * Fetch revision's username without regard for view restrictions
 463          * @return string
 464          */
 465         public function getRawUserText() {
 466                 return $this->mUserText;
 467         }
 468
 469         /**
 470          * Fetch revision comment if it's available to all users
 471          * @return string
 472          */
 473         function getComment() {
 474                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 475                         return "";
 476                 } else {
 477                         return $this->mComment;
 478                 }
 479         }
 480
 481         /**
 482          * Fetch revision comment without regard for the current user's permissions
 483          * @return string
 484          */
 485         public function getRawComment() {
 486                 return $this->mComment;
 487         }
 488
 489         /**
 490          * @return bool
 491          */
 492         public function isMinor() {
 493                 return (bool)$this->mMinorEdit;
 494         }
 495
 496         /**
 497          * int $field one of DELETED_* bitfield constants
 498          * @return bool
 499          */
 500         public function isDeleted( $field ) {
 501                 return ($this->mDeleted & $field) == $field;
 502         }
 503
 504         /**
 505          * Fetch revision text if it's available to all users
 506          * @return string
 507          */
 508         public function getText( $isPublic = true ) {
 509                 if( $isPublic && $this->isDeleted( self::DELETED_TEXT ) ) {
 510                         return "";
 511                 } else if( !$this->userCan( self::DELETED_TEXT ) ) {
 512                         return "";
 513                 } else {
 514                         return $this->getRawText();
 515                 }
 516         }
 517
 518         /**
 519          * Fetch revision text without regard for view restrictions
 520          * @return string
 521          */
 522         public function getRawText() {
 523                 if( is_null( $this->mText ) ) {
 524                         // Revision text is immutable. Load on demand:
 525                         $this->mText = $this->loadText();
 526                 }
 527                 return $this->mText;
 528         }
 529
 530         /**
 531          * @return string
 532          */
 533         public function getTimestamp() {
 534                 return wfTimestamp(TS_MW, $this->mTimestamp);
 535         }
 536
 537         /**
 538          * @return bool
 539          */
 540         public function isCurrent() {
 541                 return $this->mCurrent;
 542         }
 543
 544         /**
 545          * Get previous revision for this title
 546          * @return Revision
 547          */
 548         public function getPrevious() {
 549                 if( $this->getTitle() ) {
 550                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 551                         if( $prev ) {
 552                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 553                         }
 554                 }
 555                 return null;
 556         }
 557
 558         /**
 559          * @return Revision
 560          */
 561         public function getNext() {
 562                 if( $this->getTitle() ) {
 563                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 564                         if ( $next ) {
 565                                 return Revision::newFromTitle( $this->getTitle(), $next );
 566                         }
 567                 }
 568                 return null;
 569         }
 570
 571         /**
 572          * Get previous revision Id for this page_id
 573          * This is used to populate rev_parent_id on save
 574          * @param Database $db
 575          * @return int
 576          */
 577         private function getPreviousRevisionId( $db ) {
 578                 if( is_null($this->mPage) ) {
 579                         return 0;
 580                 }
 581                 # Use page_latest if ID is not given
 582                 if( !$this->mId ) {
 583                         $prevId = $db->selectField( 'page', 'page_latest',
 584                                 array( 'page_id' => $this->mPage ),
 585                                 __METHOD__ );
 586                 } else {
 587                         $prevId = $db->selectField( 'revision', 'rev_id',
 588                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 589                                 __METHOD__,
 590                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 591                 }
 592                 return intval($prevId);
 593         }
 594
 595         /**
 596           * Get revision text associated with an old or archive row
 597           * $row is usually an object from wfFetchRow(), both the flags and the text
 598           * field must be included
 599           *
 600           * @param integer $row Id of a row
 601           * @param string $prefix table prefix (default 'old_')
 602           * @return string $text|false the text requested
 603           */
 604         public static function getRevisionText( $row, $prefix = 'old_' ) {
 605                 wfProfileIn( __METHOD__ );
 606
 607                 # Get data
 608                 $textField = $prefix . 'text';
 609                 $flagsField = $prefix . 'flags';
 610
 611                 if( isset( $row->$flagsField ) ) {
 612                         $flags = explode( ',', $row->$flagsField );
 613                 } else {
 614                         $flags = array();
 615                 }
 616
 617                 if( isset( $row->$textField ) ) {
 618                         $text = $row->$textField;
 619                 } else {
 620                         wfProfileOut( __METHOD__ );
 621                         return false;
 622                 }
 623
 624                 # Use external methods for external objects, text in table is URL-only then
 625                 if ( in_array( 'external', $flags ) ) {
 626                         $url=$text;
 627                         @list(/* $proto */,$path)=explode('://',$url,2);
 628                         if ($path=="") {
 629                                 wfProfileOut( __METHOD__ );
 630                                 return false;
 631                         }
 632                         $text=ExternalStore::fetchFromURL($url);
 633                 }
 634
 635                 // If the text was fetched without an error, convert it
 636                 if ( $text !== false ) {
 637                         if( in_array( 'gzip', $flags ) ) {
 638                                 # Deal with optional compression of archived pages.
 639                                 # This can be done periodically via maintenance/compressOld.php, and
 640                                 # as pages are saved if $wgCompressRevisions is set.
 641                                 $text = gzinflate( $text );
 642                         }
 643
 644                         if( in_array( 'object', $flags ) ) {
 645                                 # Generic compressed storage
 646                                 $obj = unserialize( $text );
 647                                 if ( !is_object( $obj ) ) {
 648                                         // Invalid object
 649                                         wfProfileOut( __METHOD__ );
 650                                         return false;
 651                                 }
 652                                 $text = $obj->getText();
 653                         }
 654
 655                         global $wgLegacyEncoding;
 656                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 657                                 # Old revisions kept around in a legacy encoding?
 658                                 # Upconvert on demand.
 659                                 global $wgInputEncoding, $wgContLang;
 660                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 661                         }
 662                 }
 663                 wfProfileOut( __METHOD__ );
 664                 return $text;
 665         }
 666
 667         /**
 668          * If $wgCompressRevisions is enabled, we will compress data.
 669          * The input string is modified in place.
 670          * Return value is the flags field: contains 'gzip' if the
 671          * data is compressed, and 'utf-8' if we're saving in UTF-8
 672          * mode.
 673          *
 674          * @param mixed $text reference to a text
 675          * @return string
 676          */
 677         public static function compressRevisionText( &$text ) {
 678                 global $wgCompressRevisions;
 679                 $flags = array();
 680
 681                 # Revisions not marked this way will be converted
 682                 # on load if $wgLegacyCharset is set in the future.
 683                 $flags[] = 'utf-8';
 684
 685                 if( $wgCompressRevisions ) {
 686                         if( function_exists( 'gzdeflate' ) ) {
 687                                 $text = gzdeflate( $text );
 688                                 $flags[] = 'gzip';
 689                         } else {
 690                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 691                         }
 692                 }
 693                 return implode( ',', $flags );
 694         }
 695
 696         /**
 697          * Insert a new revision into the database, returning the new revision ID
 698          * number on success and dies horribly on failure.
 699          *
 700          * @param Database $dbw
 701          * @return int
 702          */
 703         public function insertOn( $dbw ) {
 704                 global $wgDefaultExternalStore;
 705
 706                 wfProfileIn( __METHOD__ );
 707
 708                 $data = $this->mText;
 709                 $flags = Revision::compressRevisionText( $data );
 710
 711                 # Write to external storage if required
 712                 if( $wgDefaultExternalStore ) {
 713                         // Store and get the URL
 714                         $data = ExternalStore::randomInsert( $data );
 715                         if( !$data ) {
 716                                 throw new MWException( "Unable to store text to external storage" );
 717                         }
 718                         if( $flags ) {
 719                                 $flags .= ',';
 720                         }
 721                         $flags .= 'external';
 722                 }
 723
 724                 # Record the text (or external storage URL) to the text table
 725                 if( !isset( $this->mTextId ) ) {
 726                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 727                         $dbw->insert( 'text',
 728                                 array(
 729                                         'old_id'    => $old_id,
 730                                         'old_text'  => $data,
 731                                         'old_flags' => $flags,
 732                                 ), __METHOD__
 733                         );
 734                         $this->mTextId = $dbw->insertId();
 735                 }
 736
 737                 # Record the edit in revisions
 738                 $rev_id = isset( $this->mId )
 739                         ? $this->mId
 740                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 741                 $dbw->insert( 'revision',
 742                         array(
 743                                 'rev_id'         => $rev_id,
 744                                 'rev_page'       => $this->mPage,
 745                                 'rev_text_id'    => $this->mTextId,
 746                                 'rev_comment'    => $this->mComment,
 747                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 748                                 'rev_user'       => $this->mUser,
 749                                 'rev_user_text'  => $this->mUserText,
 750                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 751                                 'rev_deleted'    => $this->mDeleted,
 752                                 'rev_len'            => $this->mSize,
 753                                 'rev_parent_id'  => $this->mParentId ? $this->mParentId : $this->getPreviousRevisionId( $dbw )
 754                         ), __METHOD__
 755                 );
 756
 757                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 758
 759                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 760
 761                 wfProfileOut( __METHOD__ );
 762                 return $this->mId;
 763         }
 764
 765         /**
 766          * Lazy-load the revision's text.
 767          * Currently hardcoded to the 'text' table storage engine.
 768          *
 769          * @return string
 770          */
 771         private function loadText() {
 772                 wfProfileIn( __METHOD__ );
 773
 774                 // Caching may be beneficial for massive use of external storage
 775                 global $wgRevisionCacheExpiry, $wgMemc;
 776                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 777                 if( $wgRevisionCacheExpiry ) {
 778                         $text = $wgMemc->get( $key );
 779                         if( is_string( $text ) ) {
 780                                 wfProfileOut( __METHOD__ );
 781                                 return $text;
 782                         }
 783                 }
 784
 785                 // If we kept data for lazy extraction, use it now...
 786                 if ( isset( $this->mTextRow ) ) {
 787                         $row = $this->mTextRow;
 788                         $this->mTextRow = null;
 789                 } else {
 790                         $row = null;
 791                 }
 792
 793                 if( !$row ) {
 794                         // Text data is immutable; check slaves first.
 795                         $dbr = wfGetDB( DB_SLAVE );
 796                         $row = $dbr->selectRow( 'text',
 797                                 array( 'old_text', 'old_flags' ),
 798                                 array( 'old_id' => $this->getTextId() ),
 799                                 __METHOD__ );
 800                 }
 801
 802                 if( !$row ) {
 803                         // Possible slave lag!
 804                         $dbw = wfGetDB( DB_MASTER );
 805                         $row = $dbw->selectRow( 'text',
 806                                 array( 'old_text', 'old_flags' ),
 807                                 array( 'old_id' => $this->getTextId() ),
 808                                 __METHOD__ );
 809                 }
 810
 811                 $text = self::getRevisionText( $row );
 812
 813                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 814                 if( $wgRevisionCacheExpiry && $text !== false ) {
 815                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 816                 }
 817
 818                 wfProfileOut( __METHOD__ );
 819
 820                 return $text;
 821         }
 822
 823         /**
 824          * Create a new null-revision for insertion into a page's
 825          * history. This will not re-save the text, but simply refer
 826          * to the text from the previous version.
 827          *
 828          * Such revisions can for instance identify page rename
 829          * operations and other such meta-modifications.
 830          *
 831          * @param Database $dbw
 832          * @param int      $pageId ID number of the page to read from
 833          * @param string   $summary
 834          * @param bool     $minor
 835          * @return Revision
 836          */
 837         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 838                 wfProfileIn( __METHOD__ );
 839
 840                 $current = $dbw->selectRow(
 841                         array( 'page', 'revision' ),
 842                         array( 'page_latest', 'rev_text_id' ),
 843                         array(
 844                                 'page_id' => $pageId,
 845                                 'page_latest=rev_id',
 846                                 ),
 847                         __METHOD__ );
 848
 849                 if( $current ) {
 850                         $revision = new Revision( array(
 851                                 'page'       => $pageId,
 852                                 'comment'    => $summary,
 853                                 'minor_edit' => $minor,
 854                                 'text_id'    => $current->rev_text_id,
 855                                 'parent_id'  => $current->page_latest
 856                                 ) );
 857                 } else {
 858                         $revision = null;
 859                 }
 860
 861                 wfProfileOut( __METHOD__ );
 862                 return $revision;
 863         }
 864
 865         /**
 866          * Determine if the current user is allowed to view a particular
 867          * field of this revision, if it's marked as deleted.
 868          * @param int $field one of self::DELETED_TEXT,
 869          *                          self::DELETED_COMMENT,
 870          *                          self::DELETED_USER
 871          * @return bool
 872          */
 873         public function userCan( $field ) {
 874                 if( ( $this->mDeleted & $field ) == $field ) {
 875                         global $wgUser;
 876                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 877                                 ? 'suppressrevision'
 878                                 : 'deleterevision';
 879                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 880                         return $wgUser->isAllowed( $permission );
 881                 } else {
 882                         return true;
 883                 }
 884         }
 885
 886
 887         /**
 888          * Get rev_timestamp from rev_id, without loading the rest of the row
 889          * @param integer $id
 890          * @param integer $pageid, optional
 891          */
 892         static function getTimestampFromId( $id, $pageId = 0 ) {
 893                 $dbr = wfGetDB( DB_SLAVE );
 894                 $conds = array( 'rev_id' => $id );
 895                 if( $pageId ) {
 896                         $conds['rev_page'] = $pageId;
 897                 }
 898                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 899                 if ( $timestamp === false ) {
 900                         # Not in slave, try master
 901                         $dbw = wfGetDB( DB_MASTER );
 902                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 903                 }
 904                 return wfTimestamp( TS_MW, $timestamp );
 905         }
 906
 907         /**
 908          * Get count of revisions per page...not very efficient
 909          * @param Database $db
 910          * @param int $id, page id
 911          */
 912         static function countByPageId( $db, $id ) {
 913                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 914                         array( 'rev_page' => $id ), __METHOD__ );
 915                 if( $row ) {
 916                         return $row->revCount;
 917                 }
 918                 return 0;
 919         }
 920
 921         /**
 922          * Get count of revisions per page...not very efficient
 923          * @param Database $db
 924          * @param Title $title
 925          */
 926         static function countByTitle( $db, $title ) {
 927                 $id = $title->getArticleId();
 928                 if( $id ) {
 929                         return Revision::countByPageId( $db, $id );
 930                 }
 931                 return 0;
 932         }
 933 }
 934
 935 /**
 936  * Aliases for backwards compatibility with 1.6
 937  */
 938 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 939 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 940 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 941 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );