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         // Convenience field
  16         const SUPPRESSED_USER = 12;
  17         // Audience options for Revision::getText()
  18         const FOR_PUBLIC = 1;
  19         const FOR_THIS_USER = 2;
  20         const RAW = 3;
  21
  22         /**
  23          * Load a page revision from a given revision ID number.
  24          * Returns null if no such revision can be found.
  25          *
  26          * @param int $id
  27          * @access public
  28          * @static
  29          */
  30         public static function newFromId( $id ) {
  31                 return Revision::newFromConds(
  32                         array( 'page_id=rev_page',
  33                                'rev_id' => intval( $id ) ) );
  34         }
  35
  36         /**
  37          * Load either the current, or a specified, revision
  38          * that's attached to a given title. If not attached
  39          * to that title, will return null.
  40          *
  41          * @param Title $title
  42          * @param int $id
  43          * @return Revision
  44          */
  45         public static function newFromTitle( $title, $id = 0 ) {
  46                 $conds = array(
  47                         'page_namespace' => $title->getNamespace(),
  48                         'page_title' => $title->getDBkey()
  49                 );
  50                 if ( $id ) {
  51                         // Use the specified ID
  52                         $conds['rev_id'] = $id;
  53                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  54                         // Get the latest revision ID from the master
  55                         $dbw = wfGetDB( DB_MASTER );
  56                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  57                         if ( $latest === false ) {
  58                                 // Page does not exist
  59                                 return null;
  60                         }
  61                         $conds['rev_id'] = $latest;
  62                 } else {
  63                         // Use a join to get the latest revision
  64                         $conds[] = 'rev_id=page_latest';
  65                 }
  66                 $conds[] = 'page_id=rev_page';
  67                 return Revision::newFromConds( $conds );
  68         }
  69
  70         /**
  71          * Make a fake revision object from an archive table row. This is queried
  72          * for permissions or even inserted (as in Special:Undelete)
  73          * @fixme: should be a subclass for RevisionDelete. [TS]
  74          */
  75         public static function newFromArchiveRow( $row, $overrides = array() ) {
  76                 $attribs = $overrides + array(
  77                         'page'       => isset( $row->page_id ) ? $row->page_id : null,
  78                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
  79                         'comment'    => $row->ar_comment,
  80                         'user'       => $row->ar_user,
  81                         'user_text'  => $row->ar_user_text,
  82                         'timestamp'  => $row->ar_timestamp,
  83                         'minor_edit' => $row->ar_minor_edit,
  84                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
  85                         'deleted'    => $row->ar_deleted,
  86                         'len'        => $row->ar_len);
  87                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
  88                         // Pre-1.5 ar_text row
  89                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
  90                 }
  91                 return new self( $attribs );
  92         }
  93
  94         /**
  95          * Load a page revision from a given revision ID number.
  96          * Returns null if no such revision can be found.
  97          *
  98          * @param Database $db
  99          * @param int $id
 100          * @access public
 101          * @static
 102          */
 103         public static function loadFromId( $db, $id ) {
 104                 return Revision::loadFromConds( $db,
 105                         array( 'page_id=rev_page',
 106                                'rev_id' => intval( $id ) ) );
 107         }
 108
 109         /**
 110          * Load either the current, or a specified, revision
 111          * that's attached to a given page. If not attached
 112          * to that page, will return null.
 113          *
 114          * @param Database $db
 115          * @param int $pageid
 116          * @param int $id
 117          * @return Revision
 118          * @access public
 119          * @static
 120          */
 121         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 122                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
 123                 if( $id ) {
 124                         $conds['rev_id']=intval($id);
 125                 } else {
 126                         $conds[]='rev_id=page_latest';
 127                 }
 128                 return Revision::loadFromConds( $db, $conds );
 129         }
 130
 131         /**
 132          * Load either the current, or a specified, revision
 133          * that's attached to a given page. If not attached
 134          * to that page, will return null.
 135          *
 136          * @param Database $db
 137          * @param Title $title
 138          * @param int $id
 139          * @return Revision
 140          * @access public
 141          * @static
 142          */
 143         public static function loadFromTitle( $db, $title, $id = 0 ) {
 144                 if( $id ) {
 145                         $matchId = intval( $id );
 146                 } else {
 147                         $matchId = 'page_latest';
 148                 }
 149                 return Revision::loadFromConds(
 150                         $db,
 151                         array( "rev_id=$matchId",
 152                                'page_id=rev_page',
 153                                'page_namespace' => $title->getNamespace(),
 154                                'page_title'     => $title->getDBkey() ) );
 155         }
 156
 157         /**
 158          * Load the revision for the given title with the given timestamp.
 159          * WARNING: Timestamps may in some circumstances not be unique,
 160          * so this isn't the best key to use.
 161          *
 162          * @param Database $db
 163          * @param Title $title
 164          * @param string $timestamp
 165          * @return Revision
 166          * @access public
 167          * @static
 168          */
 169         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 170                 return Revision::loadFromConds(
 171                         $db,
 172                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 173                                'page_id=rev_page',
 174                                'page_namespace' => $title->getNamespace(),
 175                                'page_title'     => $title->getDBkey() ) );
 176         }
 177
 178         /**
 179          * Given a set of conditions, fetch a revision.
 180          *
 181          * @param array $conditions
 182          * @return Revision
 183          * @access private
 184          * @static
 185          */
 186         public static function newFromConds( $conditions ) {
 187                 $db = wfGetDB( DB_SLAVE );
 188                 $row = Revision::loadFromConds( $db, $conditions );
 189                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 190                         $dbw = wfGetDB( DB_MASTER );
 191                         $row = Revision::loadFromConds( $dbw, $conditions );
 192                 }
 193                 return $row;
 194         }
 195
 196         /**
 197          * Given a set of conditions, fetch a revision from
 198          * the given database connection.
 199          *
 200          * @param Database $db
 201          * @param array $conditions
 202          * @return Revision
 203          * @access private
 204          * @static
 205          */
 206         private static function loadFromConds( $db, $conditions ) {
 207                 $res = Revision::fetchFromConds( $db, $conditions );
 208                 if( $res ) {
 209                         $row = $res->fetchObject();
 210                         $res->free();
 211                         if( $row ) {
 212                                 $ret = new Revision( $row );
 213                                 return $ret;
 214                         }
 215                 }
 216                 $ret = null;
 217                 return $ret;
 218         }
 219
 220         /**
 221          * Return a wrapper for a series of database rows to
 222          * fetch all of a given page's revisions in turn.
 223          * Each row can be fed to the constructor to get objects.
 224          *
 225          * @param Title $title
 226          * @return ResultWrapper
 227          * @access public
 228          * @static
 229          */
 230         public static function fetchRevision( $title ) {
 231                 return Revision::fetchFromConds(
 232                         wfGetDB( DB_SLAVE ),
 233                         array( 'rev_id=page_latest',
 234                                'page_namespace' => $title->getNamespace(),
 235                                'page_title'     => $title->getDBkey(),
 236                                'page_id=rev_page' ) );
 237         }
 238
 239         /**
 240          * Given a set of conditions, return a ResultWrapper
 241          * which will return matching database rows with the
 242          * fields necessary to build Revision objects.
 243          *
 244          * @param Database $db
 245          * @param array $conditions
 246          * @return ResultWrapper
 247          * @access private
 248          * @static
 249          */
 250         private static function fetchFromConds( $db, $conditions ) {
 251                 $fields = self::selectFields();
 252                 $fields[] = 'page_namespace';
 253                 $fields[] = 'page_title';
 254                 $fields[] = 'page_latest';
 255                 $res = $db->select(
 256                         array( 'page', 'revision' ),
 257                         $fields,
 258                         $conditions,
 259                         __METHOD__,
 260                         array( 'LIMIT' => 1 ) );
 261                 $ret = $db->resultObject( $res );
 262                 return $ret;
 263         }
 264
 265         /**
 266          * Return the list of revision fields that should be selected to create
 267          * a new revision.
 268          */
 269         static function selectFields() {
 270                 return array(
 271                         'rev_id',
 272                         'rev_page',
 273                         'rev_text_id',
 274                         'rev_timestamp',
 275                         'rev_comment',
 276                         'rev_user_text,'.
 277                         'rev_user',
 278                         'rev_minor_edit',
 279                         'rev_deleted',
 280                         'rev_len',
 281                         'rev_parent_id'
 282                 );
 283         }
 284
 285         /**
 286          * Return the list of text fields that should be selected to read the
 287          * revision text
 288          */
 289         static function selectTextFields() {
 290                 return array(
 291                         'old_text',
 292                         'old_flags'
 293                 );
 294         }
 295         /**
 296          * Return the list of page fields that should be selected from page table
 297          */
 298         static function selectPageFields() {
 299                 return array(
 300                         'page_namespace',
 301                         'page_title',
 302                         'page_latest'
 303                 );
 304         }
 305
 306         /**
 307          * @param object $row
 308          * @access private
 309          */
 310         function Revision( $row ) {
 311                 if( is_object( $row ) ) {
 312                         $this->mId        = intval( $row->rev_id );
 313                         $this->mPage      = intval( $row->rev_page );
 314                         $this->mTextId    = intval( $row->rev_text_id );
 315                         $this->mComment   =         $row->rev_comment;
 316                         $this->mUserText  =         $row->rev_user_text;
 317                         $this->mUser      = intval( $row->rev_user );
 318                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 319                         $this->mTimestamp =         $row->rev_timestamp;
 320                         $this->mDeleted   = intval( $row->rev_deleted );
 321
 322                         if( !isset( $row->rev_parent_id ) )
 323                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 324                         else
 325                                 $this->mParentId  = intval( $row->rev_parent_id );
 326
 327                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 328                                 $this->mSize = null;
 329                         else
 330                                 $this->mSize = intval( $row->rev_len );
 331
 332                         if( isset( $row->page_latest ) ) {
 333                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 334                                 $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 335                                 $this->mTitle->resetArticleID( $this->mPage );
 336                         } else {
 337                                 $this->mCurrent = false;
 338                                 $this->mTitle = null;
 339                         }
 340
 341                         // Lazy extraction...
 342                         $this->mText      = null;
 343                         if( isset( $row->old_text ) ) {
 344                                 $this->mTextRow = $row;
 345                         } else {
 346                                 // 'text' table row entry will be lazy-loaded
 347                                 $this->mTextRow = null;
 348                         }
 349                 } elseif( is_array( $row ) ) {
 350                         // Build a new revision to be saved...
 351                         global $wgUser;
 352
 353                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 354                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 355                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 356                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 357                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 358                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 359                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 360                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 361                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 362                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 363
 364                         // Enforce spacing trimming on supplied text
 365                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 366                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 367                         $this->mTextRow   = null;
 368
 369                         $this->mTitle     = null; # Load on demand if needed
 370                         $this->mCurrent   = false;
 371                         # If we still have no len_size, see it we have the text to figure it out
 372                         if ( !$this->mSize )
 373                                 $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 374                 } else {
 375                         throw new MWException( 'Revision constructor passed invalid row format.' );
 376                 }
 377                 $this->mUnpatrolled = NULL;
 378         }
 379
 380         /**#@+
 381          * @access public
 382          */
 383
 384         /**
 385          * Get revision ID
 386          * @return int
 387          */
 388         public function getId() {
 389                 return $this->mId;
 390         }
 391
 392         /**
 393          * Get text row ID
 394          * @return int
 395          */
 396         public function getTextId() {
 397                 return $this->mTextId;
 398         }
 399
 400         /**
 401          * Get parent revision ID (the original previous page revision)
 402          * @return int
 403          */
 404         public function getParentId() {
 405                 return $this->mParentId;
 406         }
 407
 408         /**
 409          * Returns the length of the text in this revision, or null if unknown.
 410          * @return int
 411          */
 412         public function getSize() {
 413                 return $this->mSize;
 414         }
 415
 416         /**
 417          * Returns the title of the page associated with this entry.
 418          * @return Title
 419          */
 420         public function getTitle() {
 421                 if( isset( $this->mTitle ) ) {
 422                         return $this->mTitle;
 423                 }
 424                 $dbr = wfGetDB( DB_SLAVE );
 425                 $row = $dbr->selectRow(
 426                         array( 'page', 'revision' ),
 427                         array( 'page_namespace', 'page_title' ),
 428                         array( 'page_id=rev_page',
 429                                'rev_id' => $this->mId ),
 430                         'Revision::getTitle' );
 431                 if( $row ) {
 432                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 433                                                           $row->page_title );
 434                 }
 435                 return $this->mTitle;
 436         }
 437
 438         /**
 439          * Set the title of the revision
 440          * @param Title $title
 441          */
 442         public function setTitle( $title ) {
 443                 $this->mTitle = $title;
 444         }
 445
 446         /**
 447          * Get the page ID
 448          * @return int
 449          */
 450         public function getPage() {
 451                 return $this->mPage;
 452         }
 453
 454         /**
 455          * Fetch revision's user id if it's available to the specified audience.
 456          * If the specified audience does not have access to it, zero will be
 457          * returned.
 458          *
 459          * @param integer $audience One of:
 460          *      Revision::FOR_PUBLIC       to be displayed to all users
 461          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 462          *      Revision::RAW              get the ID regardless of permissions
 463          *
 464          *
 465          * @return int
 466          */
 467         public function getUser( $audience = self::FOR_PUBLIC ) {
 468                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 469                         return 0;
 470                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 471                         return 0;
 472                 } else {
 473                         return $this->mUser;
 474                 }
 475         }
 476
 477         /**
 478          * Fetch revision's user id without regard for the current user's permissions
 479          * @return string
 480          */
 481         public function getRawUser() {
 482                 return $this->mUser;
 483         }
 484
 485         /**
 486          * Fetch revision's username if it's available to the specified audience.
 487          * If the specified audience does not have access to the username, an
 488          * empty string will be returned.
 489          *
 490          * @param integer $audience One of:
 491          *      Revision::FOR_PUBLIC       to be displayed to all users
 492          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 493          *      Revision::RAW              get the text regardless of permissions
 494          *
 495          * @return string
 496          */
 497         public function getUserText( $audience = self::FOR_PUBLIC ) {
 498                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 499                         return "";
 500                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 501                         return "";
 502                 } else {
 503                         return $this->mUserText;
 504                 }
 505         }
 506
 507         /**
 508          * Fetch revision's username without regard for view restrictions
 509          * @return string
 510          */
 511         public function getRawUserText() {
 512                 return $this->mUserText;
 513         }
 514
 515         /**
 516          * Fetch revision comment if it's available to the specified audience.
 517          * If the specified audience does not have access to the comment, an
 518          * empty string will be returned.
 519          *
 520          * @param integer $audience One of:
 521          *      Revision::FOR_PUBLIC       to be displayed to all users
 522          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 523          *      Revision::RAW              get the text regardless of permissions
 524          *
 525          * @return string
 526          */
 527         function getComment( $audience = self::FOR_PUBLIC ) {
 528                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 529                         return "";
 530                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 531                         return "";
 532                 } else {
 533                         return $this->mComment;
 534                 }
 535         }
 536
 537         /**
 538          * Fetch revision comment without regard for the current user's permissions
 539          * @return string
 540          */
 541         public function getRawComment() {
 542                 return $this->mComment;
 543         }
 544
 545         /**
 546          * @return bool
 547          */
 548         public function isMinor() {
 549                 return (bool)$this->mMinorEdit;
 550         }
 551
 552         /**
 553          * @return int rcid of the unpatrolled row, zero if there isn't one
 554          */
 555         public function isUnpatrolled() {
 556                 if( $this->mUnpatrolled !== NULL ) {
 557                         return $this->mUnpatrolled;
 558                 }
 559                 $dbr = wfGetDB( DB_SLAVE );
 560                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 561                         'rc_id',
 562                         array( // Add redundant user,timestamp condition so we can use the existing index
 563                                 'rc_user_text'  => $this->getRawUserText(),
 564                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 565                                 'rc_this_oldid' => $this->getId(),
 566                                 'rc_patrolled'  => 0
 567                         ),
 568                         __METHOD__
 569                 );
 570                 return (int)$this->mUnpatrolled;
 571         }
 572
 573         /**
 574          * int $field one of DELETED_* bitfield constants
 575          * @return bool
 576          */
 577         public function isDeleted( $field ) {
 578                 return ($this->mDeleted & $field) == $field;
 579         }
 580
 581         /**
 582          * Get the deletion bitfield of the revision
 583          */
 584         public function getVisibility() {
 585                 return (int)$this->mDeleted;
 586         }
 587
 588         /**
 589          * Fetch revision text if it's available to the specified audience.
 590          * If the specified audience does not have the ability to view this
 591          * revision, an empty string will be returned.
 592          *
 593          * @param integer $audience One of:
 594          *      Revision::FOR_PUBLIC       to be displayed to all users
 595          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 596          *      Revision::RAW              get the text regardless of permissions
 597          *
 598          *
 599          * @return string
 600          */
 601         public function getText( $audience = self::FOR_PUBLIC ) {
 602                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 603                         return "";
 604                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 605                         return "";
 606                 } else {
 607                         return $this->getRawText();
 608                 }
 609         }
 610
 611         /**
 612          * Alias for getText(Revision::FOR_THIS_USER)
 613          */
 614         public function revText() {
 615                 return $this->getText( self::FOR_THIS_USER );
 616         }
 617
 618         /**
 619          * Fetch revision text without regard for view restrictions
 620          * @return string
 621          */
 622         public function getRawText() {
 623                 if( is_null( $this->mText ) ) {
 624                         // Revision text is immutable. Load on demand:
 625                         $this->mText = $this->loadText();
 626                 }
 627                 return $this->mText;
 628         }
 629
 630         /**
 631          * @return string
 632          */
 633         public function getTimestamp() {
 634                 return wfTimestamp(TS_MW, $this->mTimestamp);
 635         }
 636
 637         /**
 638          * @return bool
 639          */
 640         public function isCurrent() {
 641                 return $this->mCurrent;
 642         }
 643
 644         /**
 645          * Get previous revision for this title
 646          * @return Revision
 647          */
 648         public function getPrevious() {
 649                 if( $this->getTitle() ) {
 650                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 651                         if( $prev ) {
 652                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 653                         }
 654                 }
 655                 return null;
 656         }
 657
 658         /**
 659          * @return Revision
 660          */
 661         public function getNext() {
 662                 if( $this->getTitle() ) {
 663                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 664                         if ( $next ) {
 665                                 return Revision::newFromTitle( $this->getTitle(), $next );
 666                         }
 667                 }
 668                 return null;
 669         }
 670
 671         /**
 672          * Get previous revision Id for this page_id
 673          * This is used to populate rev_parent_id on save
 674          * @param Database $db
 675          * @return int
 676          */
 677         private function getPreviousRevisionId( $db ) {
 678                 if( is_null($this->mPage) ) {
 679                         return 0;
 680                 }
 681                 # Use page_latest if ID is not given
 682                 if( !$this->mId ) {
 683                         $prevId = $db->selectField( 'page', 'page_latest',
 684                                 array( 'page_id' => $this->mPage ),
 685                                 __METHOD__ );
 686                 } else {
 687                         $prevId = $db->selectField( 'revision', 'rev_id',
 688                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 689                                 __METHOD__,
 690                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 691                 }
 692                 return intval($prevId);
 693         }
 694
 695         /**
 696           * Get revision text associated with an old or archive row
 697           * $row is usually an object from wfFetchRow(), both the flags and the text
 698           * field must be included
 699           *
 700           * @param object $row The text data
 701           * @param string $prefix table prefix (default 'old_')
 702           * @return string $text|false the text requested
 703           */
 704         public static function getRevisionText( $row, $prefix = 'old_' ) {
 705                 wfProfileIn( __METHOD__ );
 706
 707                 # Get data
 708                 $textField = $prefix . 'text';
 709                 $flagsField = $prefix . 'flags';
 710
 711                 if( isset( $row->$flagsField ) ) {
 712                         $flags = explode( ',', $row->$flagsField );
 713                 } else {
 714                         $flags = array();
 715                 }
 716
 717                 if( isset( $row->$textField ) ) {
 718                         $text = $row->$textField;
 719                 } else {
 720                         wfProfileOut( __METHOD__ );
 721                         return false;
 722                 }
 723
 724                 # Use external methods for external objects, text in table is URL-only then
 725                 if ( in_array( 'external', $flags ) ) {
 726                         $url=$text;
 727                         @list(/* $proto */,$path)=explode('://',$url,2);
 728                         if ($path=="") {
 729                                 wfProfileOut( __METHOD__ );
 730                                 return false;
 731                         }
 732                         $text=ExternalStore::fetchFromURL($url);
 733                 }
 734
 735                 // If the text was fetched without an error, convert it
 736                 if ( $text !== false ) {
 737                         if( in_array( 'gzip', $flags ) ) {
 738                                 # Deal with optional compression of archived pages.
 739                                 # This can be done periodically via maintenance/compressOld.php, and
 740                                 # as pages are saved if $wgCompressRevisions is set.
 741                                 $text = gzinflate( $text );
 742                         }
 743
 744                         if( in_array( 'object', $flags ) ) {
 745                                 # Generic compressed storage
 746                                 $obj = unserialize( $text );
 747                                 if ( !is_object( $obj ) ) {
 748                                         // Invalid object
 749                                         wfProfileOut( __METHOD__ );
 750                                         return false;
 751                                 }
 752                                 $text = $obj->getText();
 753                         }
 754
 755                         global $wgLegacyEncoding;
 756                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) ) {
 757                                 # Old revisions kept around in a legacy encoding?
 758                                 # Upconvert on demand.
 759                                 # ("utf8" checked for compatibility with some broken
 760                                 #  conversion scripts 2008-12-30)
 761                                 global $wgInputEncoding, $wgContLang;
 762                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 763                         }
 764                 }
 765                 wfProfileOut( __METHOD__ );
 766                 return $text;
 767         }
 768
 769         /**
 770          * If $wgCompressRevisions is enabled, we will compress data.
 771          * The input string is modified in place.
 772          * Return value is the flags field: contains 'gzip' if the
 773          * data is compressed, and 'utf-8' if we're saving in UTF-8
 774          * mode.
 775          *
 776          * @param mixed $text reference to a text
 777          * @return string
 778          */
 779         public static function compressRevisionText( &$text ) {
 780                 global $wgCompressRevisions;
 781                 $flags = array();
 782
 783                 # Revisions not marked this way will be converted
 784                 # on load if $wgLegacyCharset is set in the future.
 785                 $flags[] = 'utf-8';
 786
 787                 if( $wgCompressRevisions ) {
 788                         if( function_exists( 'gzdeflate' ) ) {
 789                                 $text = gzdeflate( $text );
 790                                 $flags[] = 'gzip';
 791                         } else {
 792                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 793                         }
 794                 }
 795                 return implode( ',', $flags );
 796         }
 797
 798         /**
 799          * Insert a new revision into the database, returning the new revision ID
 800          * number on success and dies horribly on failure.
 801          *
 802          * @param Database $dbw
 803          * @return int
 804          */
 805         public function insertOn( $dbw ) {
 806                 global $wgDefaultExternalStore;
 807
 808                 wfProfileIn( __METHOD__ );
 809
 810                 $data = $this->mText;
 811                 $flags = Revision::compressRevisionText( $data );
 812
 813                 # Write to external storage if required
 814                 if( $wgDefaultExternalStore ) {
 815                         // Store and get the URL
 816                         $data = ExternalStore::insertToDefault( $data );
 817                         if( !$data ) {
 818                                 throw new MWException( "Unable to store text to external storage" );
 819                         }
 820                         if( $flags ) {
 821                                 $flags .= ',';
 822                         }
 823                         $flags .= 'external';
 824                 }
 825
 826                 # Record the text (or external storage URL) to the text table
 827                 if( !isset( $this->mTextId ) ) {
 828                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 829                         $dbw->insert( 'text',
 830                                 array(
 831                                         'old_id'    => $old_id,
 832                                         'old_text'  => $data,
 833                                         'old_flags' => $flags,
 834                                 ), __METHOD__
 835                         );
 836                         $this->mTextId = $dbw->insertId();
 837                 }
 838
 839                 # Record the edit in revisions
 840                 $rev_id = isset( $this->mId )
 841                         ? $this->mId
 842                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 843                 $dbw->insert( 'revision',
 844                         array(
 845                                 'rev_id'         => $rev_id,
 846                                 'rev_page'       => $this->mPage,
 847                                 'rev_text_id'    => $this->mTextId,
 848                                 'rev_comment'    => $this->mComment,
 849                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 850                                 'rev_user'       => $this->mUser,
 851                                 'rev_user_text'  => $this->mUserText,
 852                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 853                                 'rev_deleted'    => $this->mDeleted,
 854                                 'rev_len'            => $this->mSize,
 855                                 'rev_parent_id'  => is_null($this->mParentId) ?
 856                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 857                         ), __METHOD__
 858                 );
 859
 860                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 861
 862                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 863
 864                 wfProfileOut( __METHOD__ );
 865                 return $this->mId;
 866         }
 867
 868         /**
 869          * Lazy-load the revision's text.
 870          * Currently hardcoded to the 'text' table storage engine.
 871          *
 872          * @return string
 873          */
 874         protected function loadText() {
 875                 wfProfileIn( __METHOD__ );
 876
 877                 // Caching may be beneficial for massive use of external storage
 878                 global $wgRevisionCacheExpiry, $wgMemc;
 879                 $textId = $this->getTextId();
 880                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 881                 if( $wgRevisionCacheExpiry ) {
 882                         $text = $wgMemc->get( $key );
 883                         if( is_string( $text ) ) {
 884                                 wfDebug( __METHOD__. ": got id $textId from cache\n" );
 885                                 wfProfileOut( __METHOD__ );
 886                                 return $text;
 887                         }
 888                 }
 889
 890                 // If we kept data for lazy extraction, use it now...
 891                 if ( isset( $this->mTextRow ) ) {
 892                         $row = $this->mTextRow;
 893                         $this->mTextRow = null;
 894                 } else {
 895                         $row = null;
 896                 }
 897
 898                 if( !$row ) {
 899                         // Text data is immutable; check slaves first.
 900                         $dbr = wfGetDB( DB_SLAVE );
 901                         $row = $dbr->selectRow( 'text',
 902                                 array( 'old_text', 'old_flags' ),
 903                                 array( 'old_id' => $this->getTextId() ),
 904                                 __METHOD__ );
 905                 }
 906
 907                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 908                         // Possible slave lag!
 909                         $dbw = wfGetDB( DB_MASTER );
 910                         $row = $dbw->selectRow( 'text',
 911                                 array( 'old_text', 'old_flags' ),
 912                                 array( 'old_id' => $this->getTextId() ),
 913                                 __METHOD__ );
 914                 }
 915
 916                 $text = self::getRevisionText( $row );
 917
 918                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 919                 if( $wgRevisionCacheExpiry && $text !== false ) {
 920                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 921                 }
 922
 923                 wfProfileOut( __METHOD__ );
 924
 925                 return $text;
 926         }
 927
 928         /**
 929          * Create a new null-revision for insertion into a page's
 930          * history. This will not re-save the text, but simply refer
 931          * to the text from the previous version.
 932          *
 933          * Such revisions can for instance identify page rename
 934          * operations and other such meta-modifications.
 935          *
 936          * @param Database $dbw
 937          * @param int      $pageId ID number of the page to read from
 938          * @param string   $summary
 939          * @param bool     $minor
 940          * @return mixed Revision, or null on error
 941          */
 942         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 943                 wfProfileIn( __METHOD__ );
 944
 945                 $current = $dbw->selectRow(
 946                         array( 'page', 'revision' ),
 947                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 948                         array(
 949                                 'page_id' => $pageId,
 950                                 'page_latest=rev_id',
 951                                 ),
 952                         __METHOD__ );
 953
 954                 if( $current ) {
 955                         $revision = new Revision( array(
 956                                 'page'       => $pageId,
 957                                 'comment'    => $summary,
 958                                 'minor_edit' => $minor,
 959                                 'text_id'    => $current->rev_text_id,
 960                                 'parent_id'  => $current->page_latest,
 961                                 'len'        => $current->rev_len
 962                                 ) );
 963                 } else {
 964                         $revision = null;
 965                 }
 966
 967                 wfProfileOut( __METHOD__ );
 968                 return $revision;
 969         }
 970
 971         /**
 972          * Determine if the current user is allowed to view a particular
 973          * field of this revision, if it's marked as deleted.
 974          * @param int $field one of self::DELETED_TEXT,
 975          *                          self::DELETED_COMMENT,
 976          *                          self::DELETED_USER
 977          * @return bool
 978          */
 979         public function userCan( $field ) {
 980                 if( ( $this->mDeleted & $field ) == $field ) {
 981                         global $wgUser;
 982                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 983                                 ? 'suppressrevision'
 984                                 : 'deletedrevision';
 985                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 986                         return $wgUser->isAllowed( $permission );
 987                 } else {
 988                         return true;
 989                 }
 990         }
 991
 992
 993         /**
 994          * Get rev_timestamp from rev_id, without loading the rest of the row
 995          * @param Title $title
 996          * @param integer $id
 997          */
 998         static function getTimestampFromId( $title, $id ) {
 999                 $dbr = wfGetDB( DB_SLAVE );
1000                 // Casting fix for DB2
1001                 if ($id == '') {
1002                         $id = 0;
1003                 }
1004                 $conds = array( 'rev_id' => $id );
1005                 $conds['rev_page'] = $title->getArticleId();
1006                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1007                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1008                         # Not in slave, try master
1009                         $dbw = wfGetDB( DB_MASTER );
1010                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1011                 }
1012                 return wfTimestamp( TS_MW, $timestamp );
1013         }
1014
1015         /**
1016          * Get count of revisions per page...not very efficient
1017          * @param Database $db
1018          * @param int $id, page id
1019          */
1020         static function countByPageId( $db, $id ) {
1021                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1022                         array( 'rev_page' => $id ), __METHOD__ );
1023                 if( $row ) {
1024                         return $row->revCount;
1025                 }
1026                 return 0;
1027         }
1028
1029         /**
1030          * Get count of revisions per page...not very efficient
1031          * @param Database $db
1032          * @param Title $title
1033          */
1034         static function countByTitle( $db, $title ) {
1035                 $id = $title->getArticleId();
1036                 if( $id ) {
1037                         return Revision::countByPageId( $db, $id );
1038                 }
1039                 return 0;
1040         }
1041 }
1042
1043 /**
1044  * Aliases for backwards compatibility with 1.6
1045  */
1046 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1047 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1048 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1049 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );