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         // Audience options for Revision::getText()
  17         const FOR_PUBLIC = 1;
  18         const FOR_THIS_USER = 2;
  19         const RAW = 3;
  20
  21         /**
  22          * Load a page revision from a given revision ID number.
  23          * Returns null if no such revision can be found.
  24          *
  25          * @param int $id
  26          * @access public
  27          * @static
  28          */
  29         public static function newFromId( $id ) {
  30                 return Revision::newFromConds(
  31                         array( 'page_id=rev_page',
  32                                'rev_id' => intval( $id ) ) );
  33         }
  34
  35         /**
  36          * Load either the current, or a specified, revision
  37          * that's attached to a given title. If not attached
  38          * to that title, will return null.
  39          *
  40          * @param Title $title
  41          * @param int $id
  42          * @return Revision
  43          */
  44         public static function newFromTitle( $title, $id = 0 ) {
  45                 if( $id ) {
  46                         $matchId = intval( $id );
  47                 } else {
  48                         $matchId = 'page_latest';
  49                 }
  50                 return Revision::newFromConds(
  51                         array( "rev_id=$matchId",
  52                                'page_id=rev_page',
  53                                'page_namespace' => $title->getNamespace(),
  54                                'page_title'     => $title->getDBkey() ) );
  55         }
  56
  57         /**
  58          * Load a page revision from a given revision ID number.
  59          * Returns null if no such revision can be found.
  60          *
  61          * @param Database $db
  62          * @param int $id
  63          * @access public
  64          * @static
  65          */
  66         public static function loadFromId( $db, $id ) {
  67                 return Revision::loadFromConds( $db,
  68                         array( 'page_id=rev_page',
  69                                'rev_id' => intval( $id ) ) );
  70         }
  71
  72         /**
  73          * Load either the current, or a specified, revision
  74          * that's attached to a given page. If not attached
  75          * to that page, will return null.
  76          *
  77          * @param Database $db
  78          * @param int $pageid
  79          * @param int $id
  80          * @return Revision
  81          * @access public
  82          * @static
  83          */
  84         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
  85                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  86                 if( $id ) {
  87                         $conds['rev_id']=intval($id);
  88                 } else {
  89                         $conds[]='rev_id=page_latest';
  90                 }
  91                 return Revision::loadFromConds( $db, $conds );
  92         }
  93
  94         /**
  95          * Load either the current, or a specified, revision
  96          * that's attached to a given page. If not attached
  97          * to that page, will return null.
  98          *
  99          * @param Database $db
 100          * @param Title $title
 101          * @param int $id
 102          * @return Revision
 103          * @access public
 104          * @static
 105          */
 106         public static function loadFromTitle( $db, $title, $id = 0 ) {
 107                 if( $id ) {
 108                         $matchId = intval( $id );
 109                 } else {
 110                         $matchId = 'page_latest';
 111                 }
 112                 return Revision::loadFromConds(
 113                         $db,
 114                         array( "rev_id=$matchId",
 115                                'page_id=rev_page',
 116                                'page_namespace' => $title->getNamespace(),
 117                                'page_title'     => $title->getDBkey() ) );
 118         }
 119
 120         /**
 121          * Load the revision for the given title with the given timestamp.
 122          * WARNING: Timestamps may in some circumstances not be unique,
 123          * so this isn't the best key to use.
 124          *
 125          * @param Database $db
 126          * @param Title $title
 127          * @param string $timestamp
 128          * @return Revision
 129          * @access public
 130          * @static
 131          */
 132         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 133                 return Revision::loadFromConds(
 134                         $db,
 135                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 136                                'page_id=rev_page',
 137                                'page_namespace' => $title->getNamespace(),
 138                                'page_title'     => $title->getDBkey() ) );
 139         }
 140
 141         /**
 142          * Given a set of conditions, fetch a revision.
 143          *
 144          * @param array $conditions
 145          * @return Revision
 146          * @access private
 147          * @static
 148          */
 149         private static function newFromConds( $conditions ) {
 150                 $db = wfGetDB( DB_SLAVE );
 151                 $row = Revision::loadFromConds( $db, $conditions );
 152                 if( is_null( $row ) ) {
 153                         $dbw = wfGetDB( DB_MASTER );
 154                         $row = Revision::loadFromConds( $dbw, $conditions );
 155                 }
 156                 return $row;
 157         }
 158
 159         /**
 160          * Given a set of conditions, fetch a revision from
 161          * the given database connection.
 162          *
 163          * @param Database $db
 164          * @param array $conditions
 165          * @return Revision
 166          * @access private
 167          * @static
 168          */
 169         private static function loadFromConds( $db, $conditions ) {
 170                 $res = Revision::fetchFromConds( $db, $conditions );
 171                 if( $res ) {
 172                         $row = $res->fetchObject();
 173                         $res->free();
 174                         if( $row ) {
 175                                 $ret = new Revision( $row );
 176                                 return $ret;
 177                         }
 178                 }
 179                 $ret = null;
 180                 return $ret;
 181         }
 182
 183         /**
 184          * Return a wrapper for a series of database rows to
 185          * fetch all of a given page's revisions in turn.
 186          * Each row can be fed to the constructor to get objects.
 187          *
 188          * @param Title $title
 189          * @return ResultWrapper
 190          * @access public
 191          * @static
 192          */
 193         public static function fetchAllRevisions( $title ) {
 194                 return Revision::fetchFromConds(
 195                         wfGetDB( DB_SLAVE ),
 196                         array( 'page_namespace' => $title->getNamespace(),
 197                                'page_title'     => $title->getDBkey(),
 198                                'page_id=rev_page' ) );
 199         }
 200
 201         /**
 202          * Return a wrapper for a series of database rows to
 203          * fetch all of a given page's revisions in turn.
 204          * Each row can be fed to the constructor to get objects.
 205          *
 206          * @param Title $title
 207          * @return ResultWrapper
 208          * @access public
 209          * @static
 210          */
 211         public static function fetchRevision( $title ) {
 212                 return Revision::fetchFromConds(
 213                         wfGetDB( DB_SLAVE ),
 214                         array( 'rev_id=page_latest',
 215                                'page_namespace' => $title->getNamespace(),
 216                                'page_title'     => $title->getDBkey(),
 217                                'page_id=rev_page' ) );
 218         }
 219
 220         /**
 221          * Given a set of conditions, return a ResultWrapper
 222          * which will return matching database rows with the
 223          * fields necessary to build Revision objects.
 224          *
 225          * @param Database $db
 226          * @param array $conditions
 227          * @return ResultWrapper
 228          * @access private
 229          * @static
 230          */
 231         private static function fetchFromConds( $db, $conditions ) {
 232                 $fields = self::selectFields();
 233                 $fields[] = 'page_namespace';
 234                 $fields[] = 'page_title';
 235                 $fields[] = 'page_latest';
 236                 $res = $db->select(
 237                         array( 'page', 'revision' ),
 238                         $fields,
 239                         $conditions,
 240                         'Revision::fetchRow',
 241                         array( 'LIMIT' => 1 ) );
 242                 $ret = $db->resultObject( $res );
 243                 return $ret;
 244         }
 245
 246         /**
 247          * Return the list of revision fields that should be selected to create
 248          * a new revision.
 249          */
 250         static function selectFields() {
 251                 return array(
 252                         'rev_id',
 253                         'rev_page',
 254                         'rev_text_id',
 255                         'rev_timestamp',
 256                         'rev_comment',
 257                         'rev_user_text,'.
 258                         'rev_user',
 259                         'rev_minor_edit',
 260                         'rev_deleted',
 261                         'rev_len',
 262                         'rev_parent_id'
 263                 );
 264         }
 265
 266         /**
 267          * Return the list of text fields that should be selected to read the
 268          * revision text
 269          */
 270         static function selectTextFields() {
 271                 return array(
 272                         'old_text',
 273                         'old_flags'
 274                 );
 275         }
 276         /**
 277          * Return the list of page fields that should be selected from page table
 278          */
 279         static function selectPageFields() {
 280                 return array(
 281                         'page_namespace',
 282                         'page_title',
 283                         'page_latest'
 284                 );
 285         }
 286
 287         /**
 288          * @param object $row
 289          * @access private
 290          */
 291         function Revision( $row ) {
 292                 if( is_object( $row ) ) {
 293                         $this->mId        = intval( $row->rev_id );
 294                         $this->mPage      = intval( $row->rev_page );
 295                         $this->mTextId    = intval( $row->rev_text_id );
 296                         $this->mComment   =         $row->rev_comment;
 297                         $this->mUserText  =         $row->rev_user_text;
 298                         $this->mUser      = intval( $row->rev_user );
 299                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 300                         $this->mTimestamp =         $row->rev_timestamp;
 301                         $this->mDeleted   = intval( $row->rev_deleted );
 302
 303                         if( !isset( $row->rev_parent_id ) )
 304                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 305                         else
 306                                 $this->mParentId  = intval( $row->rev_parent_id );
 307
 308                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 309                                 $this->mSize = null;
 310                         else
 311                                 $this->mSize = intval( $row->rev_len );
 312
 313                         if( isset( $row->page_latest ) ) {
 314                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 315                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 316                                                                       $row->page_title );
 317                         } else {
 318                                 $this->mCurrent = false;
 319                                 $this->mTitle = null;
 320                         }
 321
 322                         // Lazy extraction...
 323                         $this->mText      = null;
 324                         if( isset( $row->old_text ) ) {
 325                                 $this->mTextRow = $row;
 326                         } else {
 327                                 // 'text' table row entry will be lazy-loaded
 328                                 $this->mTextRow = null;
 329                         }
 330                 } elseif( is_array( $row ) ) {
 331                         // Build a new revision to be saved...
 332                         global $wgUser;
 333
 334                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 335                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 336                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 337                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 338                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 339                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 340                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 341                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 342                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 343                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 344
 345                         // Enforce spacing trimming on supplied text
 346                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 347                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 348                         $this->mTextRow   = null;
 349
 350                         $this->mTitle     = null; # Load on demand if needed
 351                         $this->mCurrent   = false;
 352                         # If we still have no len_size, see it we have the text to figure it out
 353                         if ( !$this->mSize )
 354                                 $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 355                 } else {
 356                         throw new MWException( 'Revision constructor passed invalid row format.' );
 357                 }
 358         }
 359
 360         /**#@+
 361          * @access public
 362          */
 363
 364         /**
 365          * Get revision ID
 366          * @return int
 367          */
 368         public function getId() {
 369                 return $this->mId;
 370         }
 371
 372         /**
 373          * Get text row ID
 374          * @return int
 375          */
 376         public function getTextId() {
 377                 return $this->mTextId;
 378         }
 379
 380         /**
 381          * Get parent revision ID (the original previous page revision)
 382          * @return int
 383          */
 384         public function getParentId() {
 385                 return $this->mParentId;
 386         }
 387
 388         /**
 389          * Returns the length of the text in this revision, or null if unknown.
 390          * @return int
 391          */
 392         public function getSize() {
 393                 return $this->mSize;
 394         }
 395
 396         /**
 397          * Returns the title of the page associated with this entry.
 398          * @return Title
 399          */
 400         public function getTitle() {
 401                 if( isset( $this->mTitle ) ) {
 402                         return $this->mTitle;
 403                 }
 404                 $dbr = wfGetDB( DB_SLAVE );
 405                 $row = $dbr->selectRow(
 406                         array( 'page', 'revision' ),
 407                         array( 'page_namespace', 'page_title' ),
 408                         array( 'page_id=rev_page',
 409                                'rev_id' => $this->mId ),
 410                         'Revision::getTitle' );
 411                 if( $row ) {
 412                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 413                                                           $row->page_title );
 414                 }
 415                 return $this->mTitle;
 416         }
 417
 418         /**
 419          * Set the title of the revision
 420          * @param Title $title
 421          */
 422         public function setTitle( $title ) {
 423                 $this->mTitle = $title;
 424         }
 425
 426         /**
 427          * Get the page ID
 428          * @return int
 429          */
 430         public function getPage() {
 431                 return $this->mPage;
 432         }
 433
 434         /**
 435          * Fetch revision's user id if it's available to the specified audience.
 436          * If the specified audience does not have access to it, zero will be
 437          * returned.
 438          *
 439          * @param integer $audience One of:
 440          *      Revision::FOR_PUBLIC       to be displayed to all users
 441          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 442          *      Revision::RAW              get the ID regardless of permissions
 443          *
 444          *
 445          * @return int
 446          */
 447         public function getUser( $audience = self::FOR_PUBLIC ) {
 448                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 449                         return 0;
 450                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 451                         return 0;
 452                 } else {
 453                         return $this->mUser;
 454                 }
 455         }
 456
 457         /**
 458          * Fetch revision's user id without regard for the current user's permissions
 459          * @return string
 460          */
 461         public function getRawUser() {
 462                 return $this->mUser;
 463         }
 464
 465         /**
 466          * Fetch revision's username if it's available to the specified audience.
 467          * If the specified audience does not have access to the username, an
 468          * empty string will be returned.
 469          *
 470          * @param integer $audience One of:
 471          *      Revision::FOR_PUBLIC       to be displayed to all users
 472          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 473          *      Revision::RAW              get the text regardless of permissions
 474          *
 475          * @return string
 476          */
 477         public function getUserText( $audience = self::FOR_PUBLIC ) {
 478                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 479                         return "";
 480                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 481                         return "";
 482                 } else {
 483                         return $this->mUserText;
 484                 }
 485         }
 486
 487         /**
 488          * Fetch revision's username without regard for view restrictions
 489          * @return string
 490          */
 491         public function getRawUserText() {
 492                 return $this->mUserText;
 493         }
 494
 495         /**
 496          * Fetch revision comment if it's available to the specified audience.
 497          * If the specified audience does not have access to the comment, an
 498          * empty string will be returned.
 499          *
 500          * @param integer $audience One of:
 501          *      Revision::FOR_PUBLIC       to be displayed to all users
 502          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 503          *      Revision::RAW              get the text regardless of permissions
 504          *
 505          * @return string
 506          */
 507         function getComment( $audience = self::FOR_PUBLIC ) {
 508                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 509                         return "";
 510                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 511                         return "";
 512                 } else {
 513                         return $this->mComment;
 514                 }
 515         }
 516
 517         /**
 518          * Fetch revision comment without regard for the current user's permissions
 519          * @return string
 520          */
 521         public function getRawComment() {
 522                 return $this->mComment;
 523         }
 524
 525         /**
 526          * @return bool
 527          */
 528         public function isMinor() {
 529                 return (bool)$this->mMinorEdit;
 530         }
 531
 532         /**
 533          * int $field one of DELETED_* bitfield constants
 534          * @return bool
 535          */
 536         public function isDeleted( $field ) {
 537                 return ($this->mDeleted & $field) == $field;
 538         }
 539
 540         /**
 541          * Fetch revision text if it's available to the specified audience.
 542          * If the specified audience does not have the ability to view this
 543          * revision, an empty string will be returned.
 544          *
 545          * @param integer $audience One of:
 546          *      Revision::FOR_PUBLIC       to be displayed to all users
 547          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 548          *      Revision::RAW              get the text regardless of permissions
 549          *
 550          *
 551          * @return string
 552          */
 553         public function getText( $audience = self::FOR_PUBLIC ) {
 554                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 555                         return "";
 556                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 557                         return "";
 558                 } else {
 559                         return $this->getRawText();
 560                 }
 561         }
 562
 563         /**
 564          * Alias for getText(Revision::FOR_THIS_USER)
 565          */
 566         public function revText() {
 567                 return $this->getText( self::FOR_THIS_USER );
 568         }
 569
 570         /**
 571          * Fetch revision text without regard for view restrictions
 572          * @return string
 573          */
 574         public function getRawText() {
 575                 if( is_null( $this->mText ) ) {
 576                         // Revision text is immutable. Load on demand:
 577                         $this->mText = $this->loadText();
 578                 }
 579                 return $this->mText;
 580         }
 581
 582         /**
 583          * @return string
 584          */
 585         public function getTimestamp() {
 586                 return wfTimestamp(TS_MW, $this->mTimestamp);
 587         }
 588
 589         /**
 590          * @return bool
 591          */
 592         public function isCurrent() {
 593                 return $this->mCurrent;
 594         }
 595
 596         /**
 597          * Get previous revision for this title
 598          * @return Revision
 599          */
 600         public function getPrevious() {
 601                 if( $this->getTitle() ) {
 602                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 603                         if( $prev ) {
 604                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 605                         }
 606                 }
 607                 return null;
 608         }
 609
 610         /**
 611          * @return Revision
 612          */
 613         public function getNext() {
 614                 if( $this->getTitle() ) {
 615                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 616                         if ( $next ) {
 617                                 return Revision::newFromTitle( $this->getTitle(), $next );
 618                         }
 619                 }
 620                 return null;
 621         }
 622
 623         /**
 624          * Get previous revision Id for this page_id
 625          * This is used to populate rev_parent_id on save
 626          * @param Database $db
 627          * @return int
 628          */
 629         private function getPreviousRevisionId( $db ) {
 630                 if( is_null($this->mPage) ) {
 631                         return 0;
 632                 }
 633                 # Use page_latest if ID is not given
 634                 if( !$this->mId ) {
 635                         $prevId = $db->selectField( 'page', 'page_latest',
 636                                 array( 'page_id' => $this->mPage ),
 637                                 __METHOD__ );
 638                 } else {
 639                         $prevId = $db->selectField( 'revision', 'rev_id',
 640                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 641                                 __METHOD__,
 642                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 643                 }
 644                 return intval($prevId);
 645         }
 646
 647         /**
 648           * Get revision text associated with an old or archive row
 649           * $row is usually an object from wfFetchRow(), both the flags and the text
 650           * field must be included
 651           *
 652           * @param integer $row Id of a row
 653           * @param string $prefix table prefix (default 'old_')
 654           * @return string $text|false the text requested
 655           */
 656         public static function getRevisionText( $row, $prefix = 'old_' ) {
 657                 wfProfileIn( __METHOD__ );
 658
 659                 # Get data
 660                 $textField = $prefix . 'text';
 661                 $flagsField = $prefix . 'flags';
 662
 663                 if( isset( $row->$flagsField ) ) {
 664                         $flags = explode( ',', $row->$flagsField );
 665                 } else {
 666                         $flags = array();
 667                 }
 668
 669                 if( isset( $row->$textField ) ) {
 670                         $text = $row->$textField;
 671                 } else {
 672                         wfProfileOut( __METHOD__ );
 673                         return false;
 674                 }
 675
 676                 # Use external methods for external objects, text in table is URL-only then
 677                 if ( in_array( 'external', $flags ) ) {
 678                         $url=$text;
 679                         @list(/* $proto */,$path)=explode('://',$url,2);
 680                         if ($path=="") {
 681                                 wfProfileOut( __METHOD__ );
 682                                 return false;
 683                         }
 684                         $text=ExternalStore::fetchFromURL($url);
 685                 }
 686
 687                 // If the text was fetched without an error, convert it
 688                 if ( $text !== false ) {
 689                         if( in_array( 'gzip', $flags ) ) {
 690                                 # Deal with optional compression of archived pages.
 691                                 # This can be done periodically via maintenance/compressOld.php, and
 692                                 # as pages are saved if $wgCompressRevisions is set.
 693                                 $text = gzinflate( $text );
 694                         }
 695
 696                         if( in_array( 'object', $flags ) ) {
 697                                 # Generic compressed storage
 698                                 $obj = unserialize( $text );
 699                                 if ( !is_object( $obj ) ) {
 700                                         // Invalid object
 701                                         wfProfileOut( __METHOD__ );
 702                                         return false;
 703                                 }
 704                                 $text = $obj->getText();
 705                         }
 706
 707                         global $wgLegacyEncoding;
 708                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 709                                 # Old revisions kept around in a legacy encoding?
 710                                 # Upconvert on demand.
 711                                 global $wgInputEncoding, $wgContLang;
 712                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 713                         }
 714                 }
 715                 wfProfileOut( __METHOD__ );
 716                 return $text;
 717         }
 718
 719         /**
 720          * If $wgCompressRevisions is enabled, we will compress data.
 721          * The input string is modified in place.
 722          * Return value is the flags field: contains 'gzip' if the
 723          * data is compressed, and 'utf-8' if we're saving in UTF-8
 724          * mode.
 725          *
 726          * @param mixed $text reference to a text
 727          * @return string
 728          */
 729         public static function compressRevisionText( &$text ) {
 730                 global $wgCompressRevisions;
 731                 $flags = array();
 732
 733                 # Revisions not marked this way will be converted
 734                 # on load if $wgLegacyCharset is set in the future.
 735                 $flags[] = 'utf-8';
 736
 737                 if( $wgCompressRevisions ) {
 738                         if( function_exists( 'gzdeflate' ) ) {
 739                                 $text = gzdeflate( $text );
 740                                 $flags[] = 'gzip';
 741                         } else {
 742                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 743                         }
 744                 }
 745                 return implode( ',', $flags );
 746         }
 747
 748         /**
 749          * Insert a new revision into the database, returning the new revision ID
 750          * number on success and dies horribly on failure.
 751          *
 752          * @param Database $dbw
 753          * @return int
 754          */
 755         public function insertOn( $dbw ) {
 756                 global $wgDefaultExternalStore;
 757
 758                 wfProfileIn( __METHOD__ );
 759
 760                 $data = $this->mText;
 761                 $flags = Revision::compressRevisionText( $data );
 762
 763                 # Write to external storage if required
 764                 if( $wgDefaultExternalStore ) {
 765                         // Store and get the URL
 766                         $data = ExternalStore::randomInsert( $data );
 767                         if( !$data ) {
 768                                 throw new MWException( "Unable to store text to external storage" );
 769                         }
 770                         if( $flags ) {
 771                                 $flags .= ',';
 772                         }
 773                         $flags .= 'external';
 774                 }
 775
 776                 # Record the text (or external storage URL) to the text table
 777                 if( !isset( $this->mTextId ) ) {
 778                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 779                         $dbw->insert( 'text',
 780                                 array(
 781                                         'old_id'    => $old_id,
 782                                         'old_text'  => $data,
 783                                         'old_flags' => $flags,
 784                                 ), __METHOD__
 785                         );
 786                         $this->mTextId = $dbw->insertId();
 787                 }
 788
 789                 # Record the edit in revisions
 790                 $rev_id = isset( $this->mId )
 791                         ? $this->mId
 792                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 793                 $dbw->insert( 'revision',
 794                         array(
 795                                 'rev_id'         => $rev_id,
 796                                 'rev_page'       => $this->mPage,
 797                                 'rev_text_id'    => $this->mTextId,
 798                                 'rev_comment'    => $this->mComment,
 799                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 800                                 'rev_user'       => $this->mUser,
 801                                 'rev_user_text'  => $this->mUserText,
 802                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 803                                 'rev_deleted'    => $this->mDeleted,
 804                                 'rev_len'            => $this->mSize,
 805                                 'rev_parent_id'  => $this->mParentId ? $this->mParentId : $this->getPreviousRevisionId( $dbw )
 806                         ), __METHOD__
 807                 );
 808
 809                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 810
 811                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 812
 813                 wfProfileOut( __METHOD__ );
 814                 return $this->mId;
 815         }
 816
 817         /**
 818          * Lazy-load the revision's text.
 819          * Currently hardcoded to the 'text' table storage engine.
 820          *
 821          * @return string
 822          */
 823         private function loadText() {
 824                 wfProfileIn( __METHOD__ );
 825
 826                 // Caching may be beneficial for massive use of external storage
 827                 global $wgRevisionCacheExpiry, $wgMemc;
 828                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 829                 if( $wgRevisionCacheExpiry ) {
 830                         $text = $wgMemc->get( $key );
 831                         if( is_string( $text ) ) {
 832                                 wfProfileOut( __METHOD__ );
 833                                 return $text;
 834                         }
 835                 }
 836
 837                 // If we kept data for lazy extraction, use it now...
 838                 if ( isset( $this->mTextRow ) ) {
 839                         $row = $this->mTextRow;
 840                         $this->mTextRow = null;
 841                 } else {
 842                         $row = null;
 843                 }
 844
 845                 if( !$row ) {
 846                         // Text data is immutable; check slaves first.
 847                         $dbr = wfGetDB( DB_SLAVE );
 848                         $row = $dbr->selectRow( 'text',
 849                                 array( 'old_text', 'old_flags' ),
 850                                 array( 'old_id' => $this->getTextId() ),
 851                                 __METHOD__ );
 852                 }
 853
 854                 if( !$row ) {
 855                         // Possible slave lag!
 856                         $dbw = wfGetDB( DB_MASTER );
 857                         $row = $dbw->selectRow( 'text',
 858                                 array( 'old_text', 'old_flags' ),
 859                                 array( 'old_id' => $this->getTextId() ),
 860                                 __METHOD__ );
 861                 }
 862
 863                 $text = self::getRevisionText( $row );
 864
 865                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 866                 if( $wgRevisionCacheExpiry && $text !== false ) {
 867                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 868                 }
 869
 870                 wfProfileOut( __METHOD__ );
 871
 872                 return $text;
 873         }
 874
 875         /**
 876          * Create a new null-revision for insertion into a page's
 877          * history. This will not re-save the text, but simply refer
 878          * to the text from the previous version.
 879          *
 880          * Such revisions can for instance identify page rename
 881          * operations and other such meta-modifications.
 882          *
 883          * @param Database $dbw
 884          * @param int      $pageId ID number of the page to read from
 885          * @param string   $summary
 886          * @param bool     $minor
 887          * @return Revision
 888          */
 889         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 890                 wfProfileIn( __METHOD__ );
 891
 892                 $current = $dbw->selectRow(
 893                         array( 'page', 'revision' ),
 894                         array( 'page_latest', 'rev_text_id' ),
 895                         array(
 896                                 'page_id' => $pageId,
 897                                 'page_latest=rev_id',
 898                                 ),
 899                         __METHOD__ );
 900
 901                 if( $current ) {
 902                         $revision = new Revision( array(
 903                                 'page'       => $pageId,
 904                                 'comment'    => $summary,
 905                                 'minor_edit' => $minor,
 906                                 'text_id'    => $current->rev_text_id,
 907                                 'parent_id'  => $current->page_latest
 908                                 ) );
 909                 } else {
 910                         $revision = null;
 911                 }
 912
 913                 wfProfileOut( __METHOD__ );
 914                 return $revision;
 915         }
 916
 917         /**
 918          * Determine if the current user is allowed to view a particular
 919          * field of this revision, if it's marked as deleted.
 920          * @param int $field one of self::DELETED_TEXT,
 921          *                          self::DELETED_COMMENT,
 922          *                          self::DELETED_USER
 923          * @return bool
 924          */
 925         public function userCan( $field ) {
 926                 if( ( $this->mDeleted & $field ) == $field ) {
 927                         global $wgUser;
 928                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 929                                 ? 'suppressrevision'
 930                                 : 'deleterevision';
 931                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 932                         return $wgUser->isAllowed( $permission );
 933                 } else {
 934                         return true;
 935                 }
 936         }
 937
 938
 939         /**
 940          * Get rev_timestamp from rev_id, without loading the rest of the row
 941          * @param integer $id
 942          * @param integer $pageid, optional
 943          */
 944         static function getTimestampFromId( $id, $pageId = 0 ) {
 945                 $dbr = wfGetDB( DB_SLAVE );
 946                 $conds = array( 'rev_id' => $id );
 947                 if( $pageId ) {
 948                         $conds['rev_page'] = $pageId;
 949                 }
 950                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 951                 if ( $timestamp === false ) {
 952                         # Not in slave, try master
 953                         $dbw = wfGetDB( DB_MASTER );
 954                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 955                 }
 956                 return wfTimestamp( TS_MW, $timestamp );
 957         }
 958
 959         /**
 960          * Get count of revisions per page...not very efficient
 961          * @param Database $db
 962          * @param int $id, page id
 963          */
 964         static function countByPageId( $db, $id ) {
 965                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 966                         array( 'rev_page' => $id ), __METHOD__ );
 967                 if( $row ) {
 968                         return $row->revCount;
 969                 }
 970                 return 0;
 971         }
 972
 973         /**
 974          * Get count of revisions per page...not very efficient
 975          * @param Database $db
 976          * @param Title $title
 977          */
 978         static function countByTitle( $db, $title ) {
 979                 $id = $title->getArticleId();
 980                 if( $id ) {
 981                         return Revision::countByPageId( $db, $id );
 982                 }
 983                 return 0;
 984         }
 985 }
 986
 987 /**
 988  * Aliases for backwards compatibility with 1.6
 989  */
 990 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 991 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 992 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 993 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );