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 $id
  37          * @return Revision
  38          * @access public
  39          * @static
  40          */
  41         public static function newFromTitle( &$title, $id = 0 ) {
  42                 if( $id ) {
  43                         $matchId = intval( $id );
  44                 } else {
  45                         $matchId = 'page_latest';
  46                 }
  47                 return Revision::newFromConds(
  48                         array( "rev_id=$matchId",
  49                                'page_id=rev_page',
  50                                'page_namespace' => $title->getNamespace(),
  51                                'page_title'     => $title->getDBkey() ) );
  52         }
  53
  54         /**
  55          * Load a page revision from a given revision ID number.
  56          * Returns null if no such revision can be found.
  57          *
  58          * @param Database $db
  59          * @param int $id
  60          * @access public
  61          * @static
  62          */
  63         public static function loadFromId( &$db, $id ) {
  64                 return Revision::loadFromConds( $db,
  65                         array( 'page_id=rev_page',
  66                                'rev_id' => intval( $id ) ) );
  67         }
  68
  69         /**
  70          * Load either the current, or a specified, revision
  71          * that's attached to a given page. If not attached
  72          * to that page, will return null.
  73          *
  74          * @param Database $db
  75          * @param int $pageid
  76          * @param int $id
  77          * @return Revision
  78          * @access public
  79          * @static
  80          */
  81         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
  82                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  83                 if( $id ) {
  84                         $conds['rev_id']=intval($id);
  85                 } else {
  86                         $conds[]='rev_id=page_latest';
  87                 }
  88                 return Revision::loadFromConds( $db, $conds );
  89         }
  90
  91         /**
  92          * Load either the current, or a specified, revision
  93          * that's attached to a given page. If not attached
  94          * to that page, will return null.
  95          *
  96          * @param Database $db
  97          * @param Title $title
  98          * @param int $id
  99          * @return Revision
 100          * @access public
 101          * @static
 102          */
 103         public static function loadFromTitle( &$db, $title, $id = 0 ) {
 104                 if( $id ) {
 105                         $matchId = intval( $id );
 106                 } else {
 107                         $matchId = 'page_latest';
 108                 }
 109                 return Revision::loadFromConds(
 110                         $db,
 111                         array( "rev_id=$matchId",
 112                                'page_id=rev_page',
 113                                'page_namespace' => $title->getNamespace(),
 114                                'page_title'     => $title->getDBkey() ) );
 115         }
 116
 117         /**
 118          * Load the revision for the given title with the given timestamp.
 119          * WARNING: Timestamps may in some circumstances not be unique,
 120          * so this isn't the best key to use.
 121          *
 122          * @param Database $db
 123          * @param Title $title
 124          * @param string $timestamp
 125          * @return Revision
 126          * @access public
 127          * @static
 128          */
 129         public static function loadFromTimestamp( &$db, &$title, $timestamp ) {
 130                 return Revision::loadFromConds(
 131                         $db,
 132                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 133                                'page_id=rev_page',
 134                                'page_namespace' => $title->getNamespace(),
 135                                'page_title'     => $title->getDBkey() ) );
 136         }
 137
 138         /**
 139          * Given a set of conditions, fetch a revision.
 140          *
 141          * @param array $conditions
 142          * @return Revision
 143          * @access private
 144          * @static
 145          */
 146         private static function newFromConds( $conditions ) {
 147                 $db = wfGetDB( DB_SLAVE );
 148                 $row = Revision::loadFromConds( $db, $conditions );
 149                 if( is_null( $row ) ) {
 150                         $dbw = wfGetDB( DB_MASTER );
 151                         $row = Revision::loadFromConds( $dbw, $conditions );
 152                 }
 153                 return $row;
 154         }
 155
 156         /**
 157          * Given a set of conditions, fetch a revision from
 158          * the given database connection.
 159          *
 160          * @param Database $db
 161          * @param array $conditions
 162          * @return Revision
 163          * @access private
 164          * @static
 165          */
 166         private static function loadFromConds( $db, $conditions ) {
 167                 $res = Revision::fetchFromConds( $db, $conditions );
 168                 if( $res ) {
 169                         $row = $res->fetchObject();
 170                         $res->free();
 171                         if( $row ) {
 172                                 $ret = new Revision( $row );
 173                                 return $ret;
 174                         }
 175                 }
 176                 $ret = null;
 177                 return $ret;
 178         }
 179
 180         /**
 181          * Return a wrapper for a series of database rows to
 182          * fetch all of a given page's revisions in turn.
 183          * Each row can be fed to the constructor to get objects.
 184          *
 185          * @param Title $title
 186          * @return ResultWrapper
 187          * @access public
 188          * @static
 189          */
 190         public static function fetchAllRevisions( &$title ) {
 191                 return Revision::fetchFromConds(
 192                         wfGetDB( DB_SLAVE ),
 193                         array( 'page_namespace' => $title->getNamespace(),
 194                                'page_title'     => $title->getDBkey(),
 195                                'page_id=rev_page' ) );
 196         }
 197
 198         /**
 199          * Return a wrapper for a series of database rows to
 200          * fetch all of a given page's revisions in turn.
 201          * Each row can be fed to the constructor to get objects.
 202          *
 203          * @param Title $title
 204          * @return ResultWrapper
 205          * @access public
 206          * @static
 207          */
 208         public static function fetchRevision( &$title ) {
 209                 return Revision::fetchFromConds(
 210                         wfGetDB( DB_SLAVE ),
 211                         array( 'rev_id=page_latest',
 212                                'page_namespace' => $title->getNamespace(),
 213                                'page_title'     => $title->getDBkey(),
 214                                'page_id=rev_page' ) );
 215         }
 216
 217         /**
 218          * Given a set of conditions, return a ResultWrapper
 219          * which will return matching database rows with the
 220          * fields necessary to build Revision objects.
 221          *
 222          * @param Database $db
 223          * @param array $conditions
 224          * @return ResultWrapper
 225          * @access private
 226          * @static
 227          */
 228         private static function fetchFromConds( $db, $conditions ) {
 229                 $fields = self::selectFields();
 230                 $fields[] = 'page_namespace';
 231                 $fields[] = 'page_title';
 232                 $fields[] = 'page_latest';
 233                 $res = $db->select(
 234                         array( 'page', 'revision' ),
 235                         $fields,
 236                         $conditions,
 237                         'Revision::fetchRow',
 238                         array( 'LIMIT' => 1 ) );
 239                 $ret = $db->resultObject( $res );
 240                 return $ret;
 241         }
 242
 243         /**
 244          * Return the list of revision fields that should be selected to create
 245          * a new revision.
 246          */
 247         static function selectFields() {
 248                 return array(
 249                         'rev_id',
 250                         'rev_page',
 251                         'rev_text_id',
 252                         'rev_timestamp',
 253                         'rev_comment',
 254                         'rev_user_text,'.
 255                         'rev_user',
 256                         'rev_minor_edit',
 257                         'rev_deleted',
 258                         'rev_len',
 259                         'rev_parent_id'
 260                 );
 261         }
 262
 263         /**
 264          * Return the list of text fields that should be selected to read the
 265          * revision text
 266          */
 267         static function selectTextFields() {
 268                 return array(
 269                         'old_text',
 270                         'old_flags'
 271                 );
 272         }
 273         /**
 274          * Return the list of page fields that should be selected from page table
 275          */
 276         static function selectPageFields() {
 277                 return array(
 278                         'page_namespace',
 279                         'page_title',
 280                         'page_latest'
 281                 );
 282         }
 283
 284         /**
 285          * @param object $row
 286          * @access private
 287          */
 288         function Revision( $row ) {
 289                 if( is_object( $row ) ) {
 290                         $this->mId        = intval( $row->rev_id );
 291                         $this->mPage      = intval( $row->rev_page );
 292                         $this->mTextId    = intval( $row->rev_text_id );
 293                         $this->mComment   =         $row->rev_comment;
 294                         $this->mUserText  =         $row->rev_user_text;
 295                         $this->mUser      = intval( $row->rev_user );
 296                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 297                         $this->mTimestamp =         $row->rev_timestamp;
 298                         $this->mDeleted   = intval( $row->rev_deleted );
 299
 300                         if( !isset( $row->rev_parent_id ) )
 301                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 302                         else
 303                                 $this->mParentId  = intval( $row->rev_parent_id );
 304
 305                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 306                                 $this->mSize = null;
 307                         else
 308                                 $this->mSize = intval( $row->rev_len );
 309
 310                         if( isset( $row->page_latest ) ) {
 311                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 312                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 313                                                                       $row->page_title );
 314                         } else {
 315                                 $this->mCurrent = false;
 316                                 $this->mTitle = null;
 317                         }
 318
 319                         // Lazy extraction...
 320                         $this->mText      = null;
 321                         if( isset( $row->old_text ) ) {
 322                                 $this->mTextRow = $row;
 323                         } else {
 324                                 // 'text' table row entry will be lazy-loaded
 325                                 $this->mTextRow = null;
 326                         }
 327                 } elseif( is_array( $row ) ) {
 328                         // Build a new revision to be saved...
 329                         global $wgUser;
 330
 331                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 332                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 333                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 334                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 335                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 336                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 337                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 338                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 339                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 340                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 341
 342                         // Enforce spacing trimming on supplied text
 343                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 344                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 345                         $this->mTextRow   = null;
 346
 347                         $this->mTitle     = null; # Load on demand if needed
 348                         $this->mCurrent   = false;
 349                         # If we still have no len_size, see it we have the text to figure it out
 350                         if ( !$this->mSize )
 351                                 $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 352                 } else {
 353                         throw new MWException( 'Revision constructor passed invalid row format.' );
 354                 }
 355         }
 356
 357         /**#@+
 358          * @access public
 359          */
 360
 361         /**
 362          * Get revision ID
 363          * @return int
 364          */
 365         public function getId() {
 366                 return $this->mId;
 367         }
 368
 369         /**
 370          * Get text row ID
 371          * @return int
 372          */
 373         public function getTextId() {
 374                 return $this->mTextId;
 375         }
 376
 377         /**
 378          * Get parent revision ID (the original previous page revision)
 379          * @return int
 380          */
 381         public function getParentId() {
 382                 return $this->mParentId;
 383         }
 384
 385         /**
 386          * Returns the length of the text in this revision, or null if unknown.
 387          * @return int
 388          */
 389         public function getSize() {
 390                 return $this->mSize;
 391         }
 392
 393         /**
 394          * Returns the title of the page associated with this entry.
 395          * @return Title
 396          */
 397         public function getTitle() {
 398                 if( isset( $this->mTitle ) ) {
 399                         return $this->mTitle;
 400                 }
 401                 $dbr = wfGetDB( DB_SLAVE );
 402                 $row = $dbr->selectRow(
 403                         array( 'page', 'revision' ),
 404                         array( 'page_namespace', 'page_title' ),
 405                         array( 'page_id=rev_page',
 406                                'rev_id' => $this->mId ),
 407                         'Revision::getTitle' );
 408                 if( $row ) {
 409                         $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 410                 }
 411                 return $this->mTitle;
 412         }
 413
 414         /**
 415          * Set the title of the revision
 416          * @param Title $title
 417          */
 418         public function setTitle( $title ) {
 419                 $this->mTitle = $title;
 420         }
 421
 422         /**
 423          * Get the page ID
 424          * @return int
 425          */
 426         public function getPage() {
 427                 return $this->mPage;
 428         }
 429
 430         /**
 431          * Fetch revision's user id if it's available to all users
 432          * @return int
 433          */
 434         public function getUser() {
 435                 if( $this->isDeleted( self::DELETED_USER ) ) {
 436                         return 0;
 437                 } else {
 438                         return $this->mUser;
 439                 }
 440         }
 441
 442         /**
 443          * Fetch revision's user id without regard for the current user's permissions
 444          * @return string
 445          */
 446         public function getRawUser() {
 447                 return $this->mUser;
 448         }
 449
 450         /**
 451          * Fetch revision's username if it's available to all users
 452          * @return string
 453          */
 454         public function getUserText() {
 455                 if( $this->isDeleted( self::DELETED_USER ) ) {
 456                         return "";
 457                 } else {
 458                         return $this->mUserText;
 459                 }
 460         }
 461
 462         /**
 463          * Fetch revision's username without regard for view restrictions
 464          * @return string
 465          */
 466         public function getRawUserText() {
 467                 return $this->mUserText;
 468         }
 469
 470         /**
 471          * Fetch revision comment if it's available to all users
 472          * @return string
 473          */
 474         function getComment() {
 475                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 476                         return "";
 477                 } else {
 478                         return $this->mComment;
 479                 }
 480         }
 481
 482         /**
 483          * Fetch revision comment without regard for the current user's permissions
 484          * @return string
 485          */
 486         public function getRawComment() {
 487                 return $this->mComment;
 488         }
 489
 490         /**
 491          * @return bool
 492          */
 493         public function isMinor() {
 494                 return (bool)$this->mMinorEdit;
 495         }
 496
 497         /**
 498          * int $field one of DELETED_* bitfield constants
 499          * @return bool
 500          */
 501         public function isDeleted( $field ) {
 502                 return ($this->mDeleted & $field) == $field;
 503         }
 504
 505         /**
 506          * Fetch revision text if it's available to all users
 507          * @return string
 508          */
 509         public function getText() {
 510                 if( $this->isDeleted( self::DELETED_TEXT ) ) {
 511                         return "";
 512                 } else {
 513                         return $this->getRawText();
 514                 }
 515         }
 516
 517         /**
 518          * Fetch revision text without regard for view restrictions
 519          * @return string
 520          */
 521         public function getRawText() {
 522                 if( is_null( $this->mText ) ) {
 523                         // Revision text is immutable. Load on demand:
 524                         $this->mText = $this->loadText();
 525                 }
 526                 return $this->mText;
 527         }
 528
 529         /**
 530          * Fetch revision text if it's available to THIS user
 531          * @return string
 532          */
 533         public function revText() {
 534                 if( !$this->userCan( self::DELETED_TEXT ) ) {
 535                         return "";
 536                 } else {
 537                         return $this->getRawText();
 538                 }
 539         }
 540
 541         /**
 542          * @return string
 543          */
 544         public function getTimestamp() {
 545                 return wfTimestamp(TS_MW, $this->mTimestamp);
 546         }
 547
 548         /**
 549          * @return bool
 550          */
 551         public function isCurrent() {
 552                 return $this->mCurrent;
 553         }
 554
 555         /**
 556          * Get previous revision for this title
 557          * @return Revision
 558          */
 559         public function getPrevious() {
 560                 $prev = $this->getTitle() ? $this->getTitle()->getPreviousRevisionID( $this->mId ) : null;
 561                 if( $prev ) {
 562                         return Revision::newFromTitle( $this->mTitle, $prev );
 563                 } else {
 564                         return null;
 565                 }
 566         }
 567
 568         /**
 569          * @return Revision
 570          */
 571         public function getNext() {
 572                 $next = $this->getTitle() ? $this->getTitle()->getNextRevisionID( $this->mId ) : null;
 573                 if ( $next ) {
 574                         return Revision::newFromTitle( $this->mTitle, $next );
 575                 } else {
 576                         return null;
 577                 }
 578         }
 579
 580         /**
 581          * Get previous revision Id for this page_id
 582          * This is used to populate rev_parent_id on save
 583          * @param Database $db
 584          * @return int
 585          */
 586         private function getPreviousRevisionId( $db ) {
 587                 if( is_null($this->mPage) ) {
 588                         return 0;
 589                 }
 590                 # Use page_latest if ID is not given
 591                 if( !$this->mId ) {
 592                         $prevId = $db->selectField( 'page', 'page_latest',
 593                                 array( 'page_id' => $this->mPage ),
 594                                 __METHOD__ );
 595                 } else {
 596                         $prevId = $db->selectField( 'revision', 'rev_id',
 597                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 598                                 __METHOD__,
 599                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 600                 }
 601                 return intval($prevId);
 602         }
 603
 604         /**
 605           * Get revision text associated with an old or archive row
 606           * $row is usually an object from wfFetchRow(), both the flags and the text
 607           * field must be included
 608           *
 609           * @param integer $row Id of a row
 610           * @param string $prefix table prefix (default 'old_')
 611           * @return string $text|false the text requested
 612           */
 613         public static function getRevisionText( $row, $prefix = 'old_' ) {
 614                 wfProfileIn( __METHOD__ );
 615
 616                 # Get data
 617                 $textField = $prefix . 'text';
 618                 $flagsField = $prefix . 'flags';
 619
 620                 if( isset( $row->$flagsField ) ) {
 621                         $flags = explode( ',', $row->$flagsField );
 622                 } else {
 623                         $flags = array();
 624                 }
 625
 626                 if( isset( $row->$textField ) ) {
 627                         $text = $row->$textField;
 628                 } else {
 629                         wfProfileOut( __METHOD__ );
 630                         return false;
 631                 }
 632
 633                 # Use external methods for external objects, text in table is URL-only then
 634                 if ( in_array( 'external', $flags ) ) {
 635                         $url=$text;
 636                         @list(/* $proto */,$path)=explode('://',$url,2);
 637                         if ($path=="") {
 638                                 wfProfileOut( __METHOD__ );
 639                                 return false;
 640                         }
 641                         $text=ExternalStore::fetchFromURL($url);
 642                 }
 643
 644                 // If the text was fetched without an error, convert it
 645                 if ( $text !== false ) {
 646                         if( in_array( 'gzip', $flags ) ) {
 647                                 # Deal with optional compression of archived pages.
 648                                 # This can be done periodically via maintenance/compressOld.php, and
 649                                 # as pages are saved if $wgCompressRevisions is set.
 650                                 $text = gzinflate( $text );
 651                         }
 652
 653                         if( in_array( 'object', $flags ) ) {
 654                                 # Generic compressed storage
 655                                 $obj = unserialize( $text );
 656                                 if ( !is_object( $obj ) ) {
 657                                         // Invalid object
 658                                         wfProfileOut( __METHOD__ );
 659                                         return false;
 660                                 }
 661                                 $text = $obj->getText();
 662                         }
 663
 664                         global $wgLegacyEncoding;
 665                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 666                                 # Old revisions kept around in a legacy encoding?
 667                                 # Upconvert on demand.
 668                                 global $wgInputEncoding, $wgContLang;
 669                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 670                         }
 671                 }
 672                 wfProfileOut( __METHOD__ );
 673                 return $text;
 674         }
 675
 676         /**
 677          * If $wgCompressRevisions is enabled, we will compress data.
 678          * The input string is modified in place.
 679          * Return value is the flags field: contains 'gzip' if the
 680          * data is compressed, and 'utf-8' if we're saving in UTF-8
 681          * mode.
 682          *
 683          * @param mixed $text reference to a text
 684          * @return string
 685          */
 686         public static function compressRevisionText( &$text ) {
 687                 global $wgCompressRevisions;
 688                 $flags = array();
 689
 690                 # Revisions not marked this way will be converted
 691                 # on load if $wgLegacyCharset is set in the future.
 692                 $flags[] = 'utf-8';
 693
 694                 if( $wgCompressRevisions ) {
 695                         if( function_exists( 'gzdeflate' ) ) {
 696                                 $text = gzdeflate( $text );
 697                                 $flags[] = 'gzip';
 698                         } else {
 699                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 700                         }
 701                 }
 702                 return implode( ',', $flags );
 703         }
 704
 705         /**
 706          * Insert a new revision into the database, returning the new revision ID
 707          * number on success and dies horribly on failure.
 708          *
 709          * @param Database $dbw
 710          * @return int
 711          */
 712         public function insertOn( &$dbw ) {
 713                 global $wgDefaultExternalStore;
 714
 715                 wfProfileIn( __METHOD__ );
 716
 717                 $data = $this->mText;
 718                 $flags = Revision::compressRevisionText( $data );
 719
 720                 # Write to external storage if required
 721                 if ( $wgDefaultExternalStore ) {
 722                         if ( is_array( $wgDefaultExternalStore ) ) {
 723                                 // Distribute storage across multiple clusters
 724                                 $store = $wgDefaultExternalStore[mt_rand(0, count( $wgDefaultExternalStore ) - 1)];
 725                         } else {
 726                                 $store = $wgDefaultExternalStore;
 727                         }
 728                         // Store and get the URL
 729                         $data = ExternalStore::insert( $store, $data );
 730                         if ( !$data ) {
 731                                 # This should only happen in the case of a configuration error, where the external store is not valid
 732                                 throw new MWException( "Unable to store text to external storage $store" );
 733                         }
 734                         if ( $flags ) {
 735                                 $flags .= ',';
 736                         }
 737                         $flags .= 'external';
 738                 }
 739
 740                 # Record the text (or external storage URL) to the text table
 741                 if( !isset( $this->mTextId ) ) {
 742                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 743                         $dbw->insert( 'text',
 744                                 array(
 745                                         'old_id'    => $old_id,
 746                                         'old_text'  => $data,
 747                                         'old_flags' => $flags,
 748                                 ), __METHOD__
 749                         );
 750                         $this->mTextId = $dbw->insertId();
 751                 }
 752
 753                 # Record the edit in revisions
 754                 $rev_id = isset( $this->mId )
 755                         ? $this->mId
 756                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 757                 $dbw->insert( 'revision',
 758                         array(
 759                                 'rev_id'         => $rev_id,
 760                                 'rev_page'       => $this->mPage,
 761                                 'rev_text_id'    => $this->mTextId,
 762                                 'rev_comment'    => $this->mComment,
 763                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 764                                 'rev_user'       => $this->mUser,
 765                                 'rev_user_text'  => $this->mUserText,
 766                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 767                                 'rev_deleted'    => $this->mDeleted,
 768                                 'rev_len'            => $this->mSize,
 769                                 'rev_parent_id'  => $this->mParentId ? $this->mParentId : $this->getPreviousRevisionId( $dbw )
 770                         ), __METHOD__
 771                 );
 772
 773                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 774
 775                 wfRunHooks( 'RevisionInsertComplete', array( &$this ) );
 776
 777                 wfProfileOut( __METHOD__ );
 778                 return $this->mId;
 779         }
 780
 781         /**
 782          * Lazy-load the revision's text.
 783          * Currently hardcoded to the 'text' table storage engine.
 784          *
 785          * @return string
 786          */
 787         private function loadText() {
 788                 wfProfileIn( __METHOD__ );
 789
 790                 // Caching may be beneficial for massive use of external storage
 791                 global $wgRevisionCacheExpiry, $wgMemc;
 792                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 793                 if( $wgRevisionCacheExpiry ) {
 794                         $text = $wgMemc->get( $key );
 795                         if( is_string( $text ) ) {
 796                                 wfProfileOut( __METHOD__ );
 797                                 return $text;
 798                         }
 799                 }
 800
 801                 // If we kept data for lazy extraction, use it now...
 802                 if ( isset( $this->mTextRow ) ) {
 803                         $row = $this->mTextRow;
 804                         $this->mTextRow = null;
 805                 } else {
 806                         $row = null;
 807                 }
 808
 809                 if( !$row ) {
 810                         // Text data is immutable; check slaves first.
 811                         $dbr = wfGetDB( DB_SLAVE );
 812                         $row = $dbr->selectRow( 'text',
 813                                 array( 'old_text', 'old_flags' ),
 814                                 array( 'old_id' => $this->getTextId() ),
 815                                 __METHOD__ );
 816                 }
 817
 818                 if( !$row ) {
 819                         // Possible slave lag!
 820                         $dbw = wfGetDB( DB_MASTER );
 821                         $row = $dbw->selectRow( 'text',
 822                                 array( 'old_text', 'old_flags' ),
 823                                 array( 'old_id' => $this->getTextId() ),
 824                                 __METHOD__ );
 825                 }
 826
 827                 $text = self::getRevisionText( $row );
 828
 829                 if( $wgRevisionCacheExpiry ) {
 830                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 831                 }
 832
 833                 wfProfileOut( __METHOD__ );
 834
 835                 return $text;
 836         }
 837
 838         /**
 839          * Create a new null-revision for insertion into a page's
 840          * history. This will not re-save the text, but simply refer
 841          * to the text from the previous version.
 842          *
 843          * Such revisions can for instance identify page rename
 844          * operations and other such meta-modifications.
 845          *
 846          * @param Database $dbw
 847          * @param int      $pageId ID number of the page to read from
 848          * @param string   $summary
 849          * @param bool     $minor
 850          * @return Revision
 851          */
 852         public static function newNullRevision( &$dbw, $pageId, $summary, $minor ) {
 853                 wfProfileIn( __METHOD__ );
 854
 855                 $current = $dbw->selectRow(
 856                         array( 'page', 'revision' ),
 857                         array( 'page_latest', 'rev_text_id' ),
 858                         array(
 859                                 'page_id' => $pageId,
 860                                 'page_latest=rev_id',
 861                                 ),
 862                         __METHOD__ );
 863
 864                 if( $current ) {
 865                         $revision = new Revision( array(
 866                                 'page'       => $pageId,
 867                                 'comment'    => $summary,
 868                                 'minor_edit' => $minor,
 869                                 'text_id'    => $current->rev_text_id,
 870                                 'parent_id'  => $current->page_latest
 871                                 ) );
 872                 } else {
 873                         $revision = null;
 874                 }
 875
 876                 wfProfileOut( __METHOD__ );
 877                 return $revision;
 878         }
 879
 880         /**
 881          * Determine if the current user is allowed to view a particular
 882          * field of this revision, if it's marked as deleted.
 883          * @param int $field one of self::DELETED_TEXT,
 884          *                          self::DELETED_COMMENT,
 885          *                          self::DELETED_USER
 886          * @return bool
 887          */
 888         public function userCan( $field ) {
 889                 if( ( $this->mDeleted & $field ) == $field ) {
 890                         global $wgUser;
 891                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 892                                 ? 'hiderevision'
 893                                 : 'deleterevision';
 894                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 895                         return $wgUser->isAllowed( $permission );
 896                 } else {
 897                         return true;
 898                 }
 899         }
 900
 901
 902         /**
 903          * Get rev_timestamp from rev_id, without loading the rest of the row
 904          * @param integer $id
 905          * @param integer $pageid, optional
 906          */
 907         static function getTimestampFromID( $id, $pageId = 0 ) {
 908                 $dbr = wfGetDB( DB_SLAVE );
 909                 $conds = array( 'rev_id' => $id );
 910                 if( $pageId ) {
 911                         $conds['rev_page'] = $pageId;
 912                 }
 913                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 914                 if ( $timestamp === false ) {
 915                         # Not in slave, try master
 916                         $dbw = wfGetDB( DB_MASTER );
 917                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 918                 }
 919                 return $timestamp;
 920         }
 921
 922         /**
 923          * Get count of revisions per page...not very efficient
 924          * @param Database $db
 925          * @param int $id, page id
 926          */
 927         static function countByPageId( $db, $id ) {
 928                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 929                         array( 'rev_page' => $id ), __METHOD__ );
 930                 if( $row ) {
 931                         return $row->revCount;
 932                 }
 933                 return 0;
 934         }
 935
 936         /**
 937          * Get count of revisions per page...not very efficient
 938          * @param Database $db
 939          * @param Title $title
 940          */
 941         static function countByTitle( $db, $title ) {
 942                 $id = $title->getArticleId();
 943                 if( $id ) {
 944                         return Revision::countByPageId( $db, $id );
 945                 }
 946                 return 0;
 947         }
 948 }
 949
 950 /**
 951  * Aliases for backwards compatibility with 1.6
 952  */
 953 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 954 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 955 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 956 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );