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,
 410                                                            $row->page_title );
 411                 }
 412                 return $this->mTitle;
 413         }
 414
 415         /**
 416          * Set the title of the revision
 417          * @param Title $title
 418          */
 419         public function setTitle( $title ) {
 420                 $this->mTitle = $title;
 421         }
 422
 423         /**
 424          * Get the page ID
 425          * @return int
 426          */
 427         public function getPage() {
 428                 return $this->mPage;
 429         }
 430
 431         /**
 432          * Fetch revision's user id if it's available to all users
 433          * @return int
 434          */
 435         public function getUser() {
 436                 if( $this->isDeleted( self::DELETED_USER ) ) {
 437                         return 0;
 438                 } else {
 439                         return $this->mUser;
 440                 }
 441         }
 442
 443         /**
 444          * Fetch revision's user id without regard for the current user's permissions
 445          * @return string
 446          */
 447         public function getRawUser() {
 448                 return $this->mUser;
 449         }
 450
 451         /**
 452          * Fetch revision's username if it's available to all users
 453          * @return string
 454          */
 455         public function getUserText() {
 456                 if( $this->isDeleted( self::DELETED_USER ) ) {
 457                         return "";
 458                 } else {
 459                         return $this->mUserText;
 460                 }
 461         }
 462
 463         /**
 464          * Fetch revision's username without regard for view restrictions
 465          * @return string
 466          */
 467         public function getRawUserText() {
 468                 return $this->mUserText;
 469         }
 470
 471         /**
 472          * Fetch revision comment if it's available to all users
 473          * @return string
 474          */
 475         function getComment() {
 476                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 477                         return "";
 478                 } else {
 479                         return $this->mComment;
 480                 }
 481         }
 482
 483         /**
 484          * Fetch revision comment without regard for the current user's permissions
 485          * @return string
 486          */
 487         public function getRawComment() {
 488                 return $this->mComment;
 489         }
 490
 491         /**
 492          * @return bool
 493          */
 494         public function isMinor() {
 495                 return (bool)$this->mMinorEdit;
 496         }
 497
 498         /**
 499          * int $field one of DELETED_* bitfield constants
 500          * @return bool
 501          */
 502         public function isDeleted( $field ) {
 503                 return ($this->mDeleted & $field) == $field;
 504         }
 505
 506         /**
 507          * Fetch revision text if it's available to all users
 508          * @return string
 509          */
 510         public function getText() {
 511                 if( $this->isDeleted( 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 $this->mText;
 528         }
 529
 530         /**
 531          * Fetch revision text if it's available to THIS user
 532          * @return string
 533          */
 534         public function revText() {
 535                 if( !$this->userCan( self::DELETED_TEXT ) ) {
 536                         return "";
 537                 } else {
 538                         return $this->getRawText();
 539                 }
 540         }
 541
 542         /**
 543          * @return string
 544          */
 545         public function getTimestamp() {
 546                 return wfTimestamp(TS_MW, $this->mTimestamp);
 547         }
 548
 549         /**
 550          * @return bool
 551          */
 552         public function isCurrent() {
 553                 return $this->mCurrent;
 554         }
 555
 556         /**
 557          * Get previous revision for this title
 558          * @return Revision
 559          */
 560         public function getPrevious() {
 561                 $prev = $this->getTitle()->getPreviousRevisionID( $this->mId );
 562                 if( $prev ) {
 563                         return Revision::newFromTitle( $this->mTitle, $prev );
 564                 } else {
 565                         return null;
 566                 }
 567         }
 568
 569         /**
 570          * @return Revision
 571          */
 572         public function getNext() {
 573                 $next = $this->getTitle()->getNextRevisionID( $this->mId );
 574                 if ( $next ) {
 575                         return Revision::newFromTitle( $this->mTitle, $next );
 576                 } else {
 577                         return null;
 578                 }
 579         }
 580
 581         /**
 582          * Get previous revision Id for this page_id
 583          * This is used to populate rev_parent_id on save
 584          * @param Database $db
 585          * @return int
 586          */
 587         private function getPreviousRevisionId( $db ) {
 588                 if( is_null($this->mPage) ) {
 589                         return 0;
 590                 }
 591                 # Use page_latest if ID is not given
 592                 if( !$this->mId ) {
 593                         $prevId = $db->selectField( 'page', 'page_latest',
 594                                 array( 'page_id' => $this->mPage ),
 595                                 __METHOD__ );
 596                 } else {
 597                         $prevId = $db->selectField( 'revision', 'rev_id',
 598                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 599                                 __METHOD__,
 600                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 601                 }
 602                 return intval($prevId);
 603         }
 604
 605         /**
 606           * Get revision text associated with an old or archive row
 607           * $row is usually an object from wfFetchRow(), both the flags and the text
 608           * field must be included
 609           *
 610           * @param integer $row Id of a row
 611           * @param string $prefix table prefix (default 'old_')
 612           * @return string $text|false the text requested
 613           */
 614         public static function getRevisionText( $row, $prefix = 'old_' ) {
 615                 wfProfileIn( __METHOD__ );
 616
 617                 # Get data
 618                 $textField = $prefix . 'text';
 619                 $flagsField = $prefix . 'flags';
 620
 621                 if( isset( $row->$flagsField ) ) {
 622                         $flags = explode( ',', $row->$flagsField );
 623                 } else {
 624                         $flags = array();
 625                 }
 626
 627                 if( isset( $row->$textField ) ) {
 628                         $text = $row->$textField;
 629                 } else {
 630                         wfProfileOut( __METHOD__ );
 631                         return false;
 632                 }
 633
 634                 # Use external methods for external objects, text in table is URL-only then
 635                 if ( in_array( 'external', $flags ) ) {
 636                         $url=$text;
 637                         @list(/* $proto */,$path)=explode('://',$url,2);
 638                         if ($path=="") {
 639                                 wfProfileOut( __METHOD__ );
 640                                 return false;
 641                         }
 642                         $text=ExternalStore::fetchFromURL($url);
 643                 }
 644
 645                 // If the text was fetched without an error, convert it
 646                 if ( $text !== false ) {
 647                         if( in_array( 'gzip', $flags ) ) {
 648                                 # Deal with optional compression of archived pages.
 649                                 # This can be done periodically via maintenance/compressOld.php, and
 650                                 # as pages are saved if $wgCompressRevisions is set.
 651                                 $text = gzinflate( $text );
 652                         }
 653
 654                         if( in_array( 'object', $flags ) ) {
 655                                 # Generic compressed storage
 656                                 $obj = unserialize( $text );
 657                                 if ( !is_object( $obj ) ) {
 658                                         // Invalid object
 659                                         wfProfileOut( __METHOD__ );
 660                                         return false;
 661                                 }
 662                                 $text = $obj->getText();
 663                         }
 664
 665                         global $wgLegacyEncoding;
 666                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 667                                 # Old revisions kept around in a legacy encoding?
 668                                 # Upconvert on demand.
 669                                 global $wgInputEncoding, $wgContLang;
 670                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 671                         }
 672                 }
 673                 wfProfileOut( __METHOD__ );
 674                 return $text;
 675         }
 676
 677         /**
 678          * If $wgCompressRevisions is enabled, we will compress data.
 679          * The input string is modified in place.
 680          * Return value is the flags field: contains 'gzip' if the
 681          * data is compressed, and 'utf-8' if we're saving in UTF-8
 682          * mode.
 683          *
 684          * @param mixed $text reference to a text
 685          * @return string
 686          */
 687         public static function compressRevisionText( &$text ) {
 688                 global $wgCompressRevisions;
 689                 $flags = array();
 690
 691                 # Revisions not marked this way will be converted
 692                 # on load if $wgLegacyCharset is set in the future.
 693                 $flags[] = 'utf-8';
 694
 695                 if( $wgCompressRevisions ) {
 696                         if( function_exists( 'gzdeflate' ) ) {
 697                                 $text = gzdeflate( $text );
 698                                 $flags[] = 'gzip';
 699                         } else {
 700                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 701                         }
 702                 }
 703                 return implode( ',', $flags );
 704         }
 705
 706         /**
 707          * Insert a new revision into the database, returning the new revision ID
 708          * number on success and dies horribly on failure.
 709          *
 710          * @param Database $dbw
 711          * @return int
 712          */
 713         public function insertOn( &$dbw ) {
 714                 global $wgDefaultExternalStore;
 715
 716                 wfProfileIn( __METHOD__ );
 717
 718                 $data = $this->mText;
 719                 $flags = Revision::compressRevisionText( $data );
 720
 721                 # Write to external storage if required
 722                 if ( $wgDefaultExternalStore ) {
 723                         if ( is_array( $wgDefaultExternalStore ) ) {
 724                                 // Distribute storage across multiple clusters
 725                                 $store = $wgDefaultExternalStore[mt_rand(0, count( $wgDefaultExternalStore ) - 1)];
 726                         } else {
 727                                 $store = $wgDefaultExternalStore;
 728                         }
 729                         // Store and get the URL
 730                         $data = ExternalStore::insert( $store, $data );
 731                         if ( !$data ) {
 732                                 # This should only happen in the case of a configuration error, where the external store is not valid
 733                                 throw new MWException( "Unable to store text to external storage $store" );
 734                         }
 735                         if ( $flags ) {
 736                                 $flags .= ',';
 737                         }
 738                         $flags .= 'external';
 739                 }
 740
 741                 # Record the text (or external storage URL) to the text table
 742                 if( !isset( $this->mTextId ) ) {
 743                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 744                         $dbw->insert( 'text',
 745                                 array(
 746                                         'old_id'    => $old_id,
 747                                         'old_text'  => $data,
 748                                         'old_flags' => $flags,
 749                                 ), __METHOD__
 750                         );
 751                         $this->mTextId = $dbw->insertId();
 752                 }
 753
 754                 # Record the edit in revisions
 755                 $rev_id = isset( $this->mId )
 756                         ? $this->mId
 757                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 758                 $dbw->insert( 'revision',
 759                         array(
 760                                 'rev_id'         => $rev_id,
 761                                 'rev_page'       => $this->mPage,
 762                                 'rev_text_id'    => $this->mTextId,
 763                                 'rev_comment'    => $this->mComment,
 764                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 765                                 'rev_user'       => $this->mUser,
 766                                 'rev_user_text'  => $this->mUserText,
 767                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 768                                 'rev_deleted'    => $this->mDeleted,
 769                                 'rev_len'            => $this->mSize,
 770                                 'rev_parent_id'  => $this->mParentId ? $this->mParentId : $this->getPreviousRevisionId( $dbw )
 771                         ), __METHOD__
 772                 );
 773
 774                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 775
 776                 wfRunHooks( 'RevisionInsertComplete', array( &$this ) );
 777
 778                 wfProfileOut( __METHOD__ );
 779                 return $this->mId;
 780         }
 781
 782         /**
 783          * Lazy-load the revision's text.
 784          * Currently hardcoded to the 'text' table storage engine.
 785          *
 786          * @return string
 787          */
 788         private function loadText() {
 789                 wfProfileIn( __METHOD__ );
 790
 791                 // Caching may be beneficial for massive use of external storage
 792                 global $wgRevisionCacheExpiry, $wgMemc;
 793                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 794                 if( $wgRevisionCacheExpiry ) {
 795                         $text = $wgMemc->get( $key );
 796                         if( is_string( $text ) ) {
 797                                 wfProfileOut( __METHOD__ );
 798                                 return $text;
 799                         }
 800                 }
 801
 802                 // If we kept data for lazy extraction, use it now...
 803                 if ( isset( $this->mTextRow ) ) {
 804                         $row = $this->mTextRow;
 805                         $this->mTextRow = null;
 806                 } else {
 807                         $row = null;
 808                 }
 809
 810                 if( !$row ) {
 811                         // Text data is immutable; check slaves first.
 812                         $dbr = wfGetDB( DB_SLAVE );
 813                         $row = $dbr->selectRow( 'text',
 814                                 array( 'old_text', 'old_flags' ),
 815                                 array( 'old_id' => $this->getTextId() ),
 816                                 __METHOD__ );
 817                 }
 818
 819                 if( !$row ) {
 820                         // Possible slave lag!
 821                         $dbw = wfGetDB( DB_MASTER );
 822                         $row = $dbw->selectRow( 'text',
 823                                 array( 'old_text', 'old_flags' ),
 824                                 array( 'old_id' => $this->getTextId() ),
 825                                 __METHOD__ );
 826                 }
 827
 828                 $text = self::getRevisionText( $row );
 829
 830                 if( $wgRevisionCacheExpiry ) {
 831                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 832                 }
 833
 834                 wfProfileOut( __METHOD__ );
 835
 836                 return $text;
 837         }
 838
 839         /**
 840          * Create a new null-revision for insertion into a page's
 841          * history. This will not re-save the text, but simply refer
 842          * to the text from the previous version.
 843          *
 844          * Such revisions can for instance identify page rename
 845          * operations and other such meta-modifications.
 846          *
 847          * @param Database $dbw
 848          * @param int      $pageId ID number of the page to read from
 849          * @param string   $summary
 850          * @param bool     $minor
 851          * @return Revision
 852          */
 853         public static function newNullRevision( &$dbw, $pageId, $summary, $minor ) {
 854                 wfProfileIn( __METHOD__ );
 855
 856                 $current = $dbw->selectRow(
 857                         array( 'page', 'revision' ),
 858                         array( 'page_latest', 'rev_text_id' ),
 859                         array(
 860                                 'page_id' => $pageId,
 861                                 'page_latest=rev_id',
 862                                 ),
 863                         __METHOD__ );
 864
 865                 if( $current ) {
 866                         $revision = new Revision( array(
 867                                 'page'       => $pageId,
 868                                 'comment'    => $summary,
 869                                 'minor_edit' => $minor,
 870                                 'text_id'    => $current->rev_text_id,
 871                                 'parent_id'  => $current->page_latest
 872                                 ) );
 873                 } else {
 874                         $revision = null;
 875                 }
 876
 877                 wfProfileOut( __METHOD__ );
 878                 return $revision;
 879         }
 880
 881         /**
 882          * Determine if the current user is allowed to view a particular
 883          * field of this revision, if it's marked as deleted.
 884          * @param int $field one of self::DELETED_TEXT,
 885          *                          self::DELETED_COMMENT,
 886          *                          self::DELETED_USER
 887          * @return bool
 888          */
 889         public function userCan( $field ) {
 890                 if( ( $this->mDeleted & $field ) == $field ) {
 891                         global $wgUser;
 892                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 893                                 ? 'hiderevision'
 894                                 : 'deleterevision';
 895                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 896                         return $wgUser->isAllowed( $permission );
 897                 } else {
 898                         return true;
 899                 }
 900         }
 901
 902
 903         /**
 904          * Get rev_timestamp from rev_id, without loading the rest of the row
 905          * @param integer $id
 906          */
 907         static function getTimestampFromID( $id ) {
 908                 $dbr = wfGetDB( DB_SLAVE );
 909                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp',
 910                         array( 'rev_id' => $id ), __METHOD__ );
 911                 if ( $timestamp === false ) {
 912                         # Not in slave, try master
 913                         $dbw = wfGetDB( DB_MASTER );
 914                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp',
 915                                 array( 'rev_id' => $id ), __METHOD__ );
 916                 }
 917                 return $timestamp;
 918         }
 919
 920         /**
 921          * Get count of revisions per page...not very efficient
 922          * @param Database $db
 923          * @param int $id, page id
 924          */
 925         static function countByPageId( $db, $id ) {
 926                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 927                         array( 'rev_page' => $id ), __METHOD__ );
 928                 if( $row ) {
 929                         return $row->revCount;
 930                 }
 931                 return 0;
 932         }
 933
 934         /**
 935          * Get count of revisions per page...not very efficient
 936          * @param Database $db
 937          * @param Title $title
 938          */
 939         static function countByTitle( $db, $title ) {
 940                 $id = $title->getArticleId();
 941                 if( $id ) {
 942                         return Revision::countByPageId( $db, $id );
 943                 }
 944                 return 0;
 945         }
 946 }
 947
 948 /**
 949  * Aliases for backwards compatibility with 1.6
 950  */
 951 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 952 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 953 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 954 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );