includes/Revision.php

   1 <?php
   2
   3 /**
   4  * @todo document
   5  */
   6 class Revision {
   7         const DELETED_TEXT = 1;
   8         const DELETED_COMMENT = 2;
   9         const DELETED_USER = 4;
  10         const DELETED_RESTRICTED = 8;
  11         // Convenience field
  12         const SUPPRESSED_USER = 12;
  13         // Audience options for Revision::getText()
  14         const FOR_PUBLIC = 1;
  15         const FOR_THIS_USER = 2;
  16         const RAW = 3;
  17
  18         /**
  19          * Load a page revision from a given revision ID number.
  20          * Returns null if no such revision can be found.
  21          *
  22          * @param $id Integer
  23          * @return Revision or null
  24          */
  25         public static function newFromId( $id ) {
  26                 return Revision::newFromConds(
  27                         array( 'page_id=rev_page',
  28                                'rev_id' => intval( $id ) ) );
  29         }
  30
  31         /**
  32          * Load either the current, or a specified, revision
  33          * that's attached to a given title. If not attached
  34          * to that title, will return null.
  35          *
  36          * @param $title Title
  37          * @param $id Integer
  38          * @return Revision or null
  39          */
  40         public static function newFromTitle( $title, $id = 0 ) {
  41                 $conds = array(
  42                         'page_namespace' => $title->getNamespace(),
  43                         'page_title' => $title->getDBkey()
  44                 );
  45                 if ( $id ) {
  46                         // Use the specified ID
  47                         $conds['rev_id'] = $id;
  48                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  49                         // Get the latest revision ID from the master
  50                         $dbw = wfGetDB( DB_MASTER );
  51                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  52                         if ( $latest === false ) {
  53                                 // Page does not exist
  54                                 return null;
  55                         }
  56                         $conds['rev_id'] = $latest;
  57                 } else {
  58                         // Use a join to get the latest revision
  59                         $conds[] = 'rev_id=page_latest';
  60                 }
  61                 $conds[] = 'page_id=rev_page';
  62                 return Revision::newFromConds( $conds );
  63         }
  64
  65         /**
  66          * Make a fake revision object from an archive table row. This is queried
  67          * for permissions or even inserted (as in Special:Undelete)
  68          * @todo Fixme: should be a subclass for RevisionDelete. [TS]
  69          */
  70         public static function newFromArchiveRow( $row, $overrides = array() ) {
  71                 $attribs = $overrides + array(
  72                         'page'       => isset( $row->page_id ) ? $row->page_id : null,
  73                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
  74                         'comment'    => $row->ar_comment,
  75                         'user'       => $row->ar_user,
  76                         'user_text'  => $row->ar_user_text,
  77                         'timestamp'  => $row->ar_timestamp,
  78                         'minor_edit' => $row->ar_minor_edit,
  79                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
  80                         'deleted'    => $row->ar_deleted,
  81                         'len'        => $row->ar_len);
  82                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
  83                         // Pre-1.5 ar_text row
  84                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
  85                 }
  86                 return new self( $attribs );
  87         }
  88
  89         /**
  90          * Load a page revision from a given revision ID number.
  91          * Returns null if no such revision can be found.
  92          *
  93          * @param $db DatabaseBase
  94          * @param $id Integer
  95          * @return Revision or null
  96          */
  97         public static function loadFromId( $db, $id ) {
  98                 return Revision::loadFromConds( $db,
  99                         array( 'page_id=rev_page',
 100                                'rev_id' => intval( $id ) ) );
 101         }
 102
 103         /**
 104          * Load either the current, or a specified, revision
 105          * that's attached to a given page. If not attached
 106          * to that page, will return null.
 107          *
 108          * @param $db DatabaseBase
 109          * @param $pageid Integer
 110          * @param $id Integer
 111          * @return Revision or null
 112          */
 113         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 114                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 115                 if( $id ) {
 116                         $conds['rev_id'] = intval( $id );
 117                 } else {
 118                         $conds[] = 'rev_id=page_latest';
 119                 }
 120                 return Revision::loadFromConds( $db, $conds );
 121         }
 122
 123         /**
 124          * Load either the current, or a specified, revision
 125          * that's attached to a given page. If not attached
 126          * to that page, will return null.
 127          *
 128          * @param $db DatabaseBase
 129          * @param $title Title
 130          * @param $id Integer
 131          * @return Revision or null
 132          */
 133         public static function loadFromTitle( $db, $title, $id = 0 ) {
 134                 if( $id ) {
 135                         $matchId = intval( $id );
 136                 } else {
 137                         $matchId = 'page_latest';
 138                 }
 139                 return Revision::loadFromConds(
 140                         $db,
 141                         array( "rev_id=$matchId",
 142                                'page_id=rev_page',
 143                                'page_namespace' => $title->getNamespace(),
 144                                'page_title'     => $title->getDBkey() ) );
 145         }
 146
 147         /**
 148          * Load the revision for the given title with the given timestamp.
 149          * WARNING: Timestamps may in some circumstances not be unique,
 150          * so this isn't the best key to use.
 151          *
 152          * @param $db Database
 153          * @param $title Title
 154          * @param $timestamp String
 155          * @return Revision or null
 156          */
 157         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 158                 return Revision::loadFromConds(
 159                         $db,
 160                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 161                                'page_id=rev_page',
 162                                'page_namespace' => $title->getNamespace(),
 163                                'page_title'     => $title->getDBkey() ) );
 164         }
 165
 166         /**
 167          * Given a set of conditions, fetch a revision.
 168          *
 169          * @param $conditions Array
 170          * @return Revision or null
 171          */
 172         public static function newFromConds( $conditions ) {
 173                 $db = wfGetDB( DB_SLAVE );
 174                 $row = Revision::loadFromConds( $db, $conditions );
 175                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 176                         $dbw = wfGetDB( DB_MASTER );
 177                         $row = Revision::loadFromConds( $dbw, $conditions );
 178                 }
 179                 return $row;
 180         }
 181
 182         /**
 183          * Given a set of conditions, fetch a revision from
 184          * the given database connection.
 185          *
 186          * @param $db Database
 187          * @param $conditions Array
 188          * @return Revision or null
 189          */
 190         private static function loadFromConds( $db, $conditions ) {
 191                 $res = Revision::fetchFromConds( $db, $conditions );
 192                 if( $res ) {
 193                         $row = $res->fetchObject();
 194                         $res->free();
 195                         if( $row ) {
 196                                 $ret = new Revision( $row );
 197                                 return $ret;
 198                         }
 199                 }
 200                 $ret = null;
 201                 return $ret;
 202         }
 203
 204         /**
 205          * Return a wrapper for a series of database rows to
 206          * fetch all of a given page's revisions in turn.
 207          * Each row can be fed to the constructor to get objects.
 208          *
 209          * @param $title Title
 210          * @return ResultWrapper
 211          */
 212         public static function fetchRevision( $title ) {
 213                 return Revision::fetchFromConds(
 214                         wfGetDB( DB_SLAVE ),
 215                         array( 'rev_id=page_latest',
 216                                'page_namespace' => $title->getNamespace(),
 217                                'page_title'     => $title->getDBkey(),
 218                                'page_id=rev_page' ) );
 219         }
 220
 221         /**
 222          * Given a set of conditions, return a ResultWrapper
 223          * which will return matching database rows with the
 224          * fields necessary to build Revision objects.
 225          *
 226          * @param $db Database
 227          * @param $conditions Array
 228          * @return ResultWrapper
 229          */
 230         private static function fetchFromConds( $db, $conditions ) {
 231                 $fields = self::selectFields();
 232                 $fields[] = 'page_namespace';
 233                 $fields[] = 'page_title';
 234                 $fields[] = 'page_latest';
 235                 $res = $db->select(
 236                         array( 'page', 'revision' ),
 237                         $fields,
 238                         $conditions,
 239                         __METHOD__,
 240                         array( 'LIMIT' => 1 ) );
 241                 $ret = $db->resultObject( $res );
 242                 return $ret;
 243         }
 244
 245         /**
 246          * Return the list of revision fields that should be selected to create
 247          * a new revision.
 248          */
 249         static function selectFields() {
 250                 return array(
 251                         'rev_id',
 252                         'rev_page',
 253                         'rev_text_id',
 254                         'rev_timestamp',
 255                         'rev_comment',
 256                         'rev_user_text,'.
 257                         'rev_user',
 258                         'rev_minor_edit',
 259                         'rev_deleted',
 260                         'rev_len',
 261                         'rev_parent_id'
 262                 );
 263         }
 264
 265         /**
 266          * Return the list of text fields that should be selected to read the
 267          * revision text
 268          */
 269         static function selectTextFields() {
 270                 return array(
 271                         'old_text',
 272                         'old_flags'
 273                 );
 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          * Constructor
 289          *
 290          * @param $row Mixed: either a database row or an array
 291          * @access private
 292          */
 293         function Revision( $row ) {
 294                 if( is_object( $row ) ) {
 295                         $this->mId        = intval( $row->rev_id );
 296                         $this->mPage      = intval( $row->rev_page );
 297                         $this->mTextId    = intval( $row->rev_text_id );
 298                         $this->mComment   =         $row->rev_comment;
 299                         $this->mUserText  =         $row->rev_user_text;
 300                         $this->mUser      = intval( $row->rev_user );
 301                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 302                         $this->mTimestamp =         $row->rev_timestamp;
 303                         $this->mDeleted   = intval( $row->rev_deleted );
 304
 305                         if( !isset( $row->rev_parent_id ) )
 306                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 307                         else
 308                                 $this->mParentId  = intval( $row->rev_parent_id );
 309
 310                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 311                                 $this->mSize = null;
 312                         else
 313                                 $this->mSize = intval( $row->rev_len );
 314
 315                         if( isset( $row->page_latest ) ) {
 316                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 317                                 $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 318                                 $this->mTitle->resetArticleID( $this->mPage );
 319                         } else {
 320                                 $this->mCurrent = false;
 321                                 $this->mTitle = null;
 322                         }
 323
 324                         // Lazy extraction...
 325                         $this->mText      = null;
 326                         if( isset( $row->old_text ) ) {
 327                                 $this->mTextRow = $row;
 328                         } else {
 329                                 // 'text' table row entry will be lazy-loaded
 330                                 $this->mTextRow = null;
 331                         }
 332                 } elseif( is_array( $row ) ) {
 333                         // Build a new revision to be saved...
 334                         global $wgUser;
 335
 336                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 337                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 338                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 339                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 340                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 341                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 342                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 343                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 344                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 345                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 346
 347                         // Enforce spacing trimming on supplied text
 348                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 349                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 350                         $this->mTextRow   = null;
 351
 352                         $this->mTitle     = null; # Load on demand if needed
 353                         $this->mCurrent   = false;
 354                         # If we still have no len_size, see it we have the text to figure it out
 355                         if ( !$this->mSize )
 356                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 357                 } else {
 358                         throw new MWException( 'Revision constructor passed invalid row format.' );
 359                 }
 360                 $this->mUnpatrolled = null;
 361         }
 362
 363         /**
 364          * Get revision ID
 365          *
 366          * @return Integer
 367          */
 368         public function getId() {
 369                 return $this->mId;
 370         }
 371
 372         /**
 373          * Get text row ID
 374          *
 375          * @return Integer
 376          */
 377         public function getTextId() {
 378                 return $this->mTextId;
 379         }
 380
 381         /**
 382          * Get parent revision ID (the original previous page revision)
 383          *
 384          * @return Integer
 385          */
 386         public function getParentId() {
 387                 return $this->mParentId;
 388         }
 389
 390         /**
 391          * Returns the length of the text in this revision, or null if unknown.
 392          *
 393          * @return Integer
 394          */
 395         public function getSize() {
 396                 return $this->mSize;
 397         }
 398
 399         /**
 400          * Returns the title of the page associated with this entry.
 401          *
 402          * @return Title
 403          */
 404         public function getTitle() {
 405                 if( isset( $this->mTitle ) ) {
 406                         return $this->mTitle;
 407                 }
 408                 $dbr = wfGetDB( DB_SLAVE );
 409                 $row = $dbr->selectRow(
 410                         array( 'page', 'revision' ),
 411                         array( 'page_namespace', 'page_title' ),
 412                         array( 'page_id=rev_page',
 413                                'rev_id' => $this->mId ),
 414                         'Revision::getTitle' );
 415                 if( $row ) {
 416                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 417                                                           $row->page_title );
 418                 }
 419                 return $this->mTitle;
 420         }
 421
 422         /**
 423          * Set the title of the revision
 424          *
 425          * @param $title Title
 426          */
 427         public function setTitle( $title ) {
 428                 $this->mTitle = $title;
 429         }
 430
 431         /**
 432          * Get the page ID
 433          *
 434          * @return Integer
 435          */
 436         public function getPage() {
 437                 return $this->mPage;
 438         }
 439
 440         /**
 441          * Fetch revision's user id if it's available to the specified audience.
 442          * If the specified audience does not have access to it, zero will be
 443          * returned.
 444          *
 445          * @param $audience Integer: one of:
 446          *      Revision::FOR_PUBLIC       to be displayed to all users
 447          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 448          *      Revision::RAW              get the ID regardless of permissions
 449          *
 450          *
 451          * @return Integer
 452          */
 453         public function getUser( $audience = self::FOR_PUBLIC ) {
 454                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 455                         return 0;
 456                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 457                         return 0;
 458                 } else {
 459                         return $this->mUser;
 460                 }
 461         }
 462
 463         /**
 464          * Fetch revision's user id without regard for the current user's permissions
 465          *
 466          * @return String
 467          */
 468         public function getRawUser() {
 469                 return $this->mUser;
 470         }
 471
 472         /**
 473          * Fetch revision's username if it's available to the specified audience.
 474          * If the specified audience does not have access to the username, an
 475          * empty string will be returned.
 476          *
 477          * @param $audience Integer: one of:
 478          *      Revision::FOR_PUBLIC       to be displayed to all users
 479          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 480          *      Revision::RAW              get the text regardless of permissions
 481          *
 482          * @return string
 483          */
 484         public function getUserText( $audience = self::FOR_PUBLIC ) {
 485                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 486                         return '';
 487                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 488                         return '';
 489                 } else {
 490                         return $this->mUserText;
 491                 }
 492         }
 493
 494         /**
 495          * Fetch revision's username without regard for view restrictions
 496          *
 497          * @return String
 498          */
 499         public function getRawUserText() {
 500                 return $this->mUserText;
 501         }
 502
 503         /**
 504          * Fetch revision comment if it's available to the specified audience.
 505          * If the specified audience does not have access to the comment, an
 506          * empty string will be returned.
 507          *
 508          * @param $audience Integer: one of:
 509          *      Revision::FOR_PUBLIC       to be displayed to all users
 510          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 511          *      Revision::RAW              get the text regardless of permissions
 512          *
 513          * @return String
 514          */
 515         function getComment( $audience = self::FOR_PUBLIC ) {
 516                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 517                         return '';
 518                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 519                         return '';
 520                 } else {
 521                         return $this->mComment;
 522                 }
 523         }
 524
 525         /**
 526          * Fetch revision comment without regard for the current user's permissions
 527          *
 528          * @return String
 529          */
 530         public function getRawComment() {
 531                 return $this->mComment;
 532         }
 533
 534         /**
 535          * @return Boolean
 536          */
 537         public function isMinor() {
 538                 return (bool)$this->mMinorEdit;
 539         }
 540
 541         /**
 542          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 543          */
 544         public function isUnpatrolled() {
 545                 if( $this->mUnpatrolled !== null ) {
 546                         return $this->mUnpatrolled;
 547                 }
 548                 $dbr = wfGetDB( DB_SLAVE );
 549                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 550                         'rc_id',
 551                         array( // Add redundant user,timestamp condition so we can use the existing index
 552                                 'rc_user_text'  => $this->getRawUserText(),
 553                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 554                                 'rc_this_oldid' => $this->getId(),
 555                                 'rc_patrolled'  => 0
 556                         ),
 557                         __METHOD__
 558                 );
 559                 return (int)$this->mUnpatrolled;
 560         }
 561
 562         /**
 563          * int $field one of DELETED_* bitfield constants
 564          *
 565          * @return Boolean
 566          */
 567         public function isDeleted( $field ) {
 568                 return ( $this->mDeleted & $field ) == $field;
 569         }
 570
 571         /**
 572          * Get the deletion bitfield of the revision
 573          */
 574         public function getVisibility() {
 575                 return (int)$this->mDeleted;
 576         }
 577
 578         /**
 579          * Fetch revision text if it's available to the specified audience.
 580          * If the specified audience does not have the ability to view this
 581          * revision, an empty string will be returned.
 582          *
 583          * @param $audience Integer: one of:
 584          *      Revision::FOR_PUBLIC       to be displayed to all users
 585          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 586          *      Revision::RAW              get the text regardless of permissions
 587          *
 588          *
 589          * @return String
 590          */
 591         public function getText( $audience = self::FOR_PUBLIC ) {
 592                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 593                         return '';
 594                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 595                         return '';
 596                 } else {
 597                         return $this->getRawText();
 598                 }
 599         }
 600
 601         /**
 602          * Alias for getText(Revision::FOR_THIS_USER)
 603          *
 604          * @return String
 605          */
 606         public function revText() {
 607                 return $this->getText( self::FOR_THIS_USER );
 608         }
 609
 610         /**
 611          * Fetch revision text without regard for view restrictions
 612          *
 613          * @return String
 614          */
 615         public function getRawText() {
 616                 if( is_null( $this->mText ) ) {
 617                         // Revision text is immutable. Load on demand:
 618                         $this->mText = $this->loadText();
 619                 }
 620                 return $this->mText;
 621         }
 622
 623         /**
 624          * @return String
 625          */
 626         public function getTimestamp() {
 627                 return wfTimestamp( TS_MW, $this->mTimestamp );
 628         }
 629
 630         /**
 631          * @return Boolean
 632          */
 633         public function isCurrent() {
 634                 return $this->mCurrent;
 635         }
 636
 637         /**
 638          * Get previous revision for this title
 639          *
 640          * @return Revision or null
 641          */
 642         public function getPrevious() {
 643                 if( $this->getTitle() ) {
 644                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 645                         if( $prev ) {
 646                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 647                         }
 648                 }
 649                 return null;
 650         }
 651
 652         /**
 653          * Get next revision for this title
 654          *
 655          * @return Revision or null
 656          */
 657         public function getNext() {
 658                 if( $this->getTitle() ) {
 659                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 660                         if ( $next ) {
 661                                 return Revision::newFromTitle( $this->getTitle(), $next );
 662                         }
 663                 }
 664                 return null;
 665         }
 666
 667         /**
 668          * Get previous revision Id for this page_id
 669          * This is used to populate rev_parent_id on save
 670          *
 671          * @param $db DatabaseBase
 672          * @return Integer
 673          */
 674         private function getPreviousRevisionId( $db ) {
 675                 if( is_null( $this->mPage ) ) {
 676                         return 0;
 677                 }
 678                 # Use page_latest if ID is not given
 679                 if( !$this->mId ) {
 680                         $prevId = $db->selectField( 'page', 'page_latest',
 681                                 array( 'page_id' => $this->mPage ),
 682                                 __METHOD__ );
 683                 } else {
 684                         $prevId = $db->selectField( 'revision', 'rev_id',
 685                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 686                                 __METHOD__,
 687                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 688                 }
 689                 return intval( $prevId );
 690         }
 691
 692         /**
 693           * Get revision text associated with an old or archive row
 694           * $row is usually an object from wfFetchRow(), both the flags and the text
 695           * field must be included
 696           *
 697           * @param $row Object: the text data
 698           * @param $prefix String: table prefix (default 'old_')
 699           * @return String: text the text requested or false on failure
 700           */
 701         public static function getRevisionText( $row, $prefix = 'old_' ) {
 702                 wfProfileIn( __METHOD__ );
 703
 704                 # Get data
 705                 $textField = $prefix . 'text';
 706                 $flagsField = $prefix . 'flags';
 707
 708                 if( isset( $row->$flagsField ) ) {
 709                         $flags = explode( ',', $row->$flagsField );
 710                 } else {
 711                         $flags = array();
 712                 }
 713
 714                 if( isset( $row->$textField ) ) {
 715                         $text = $row->$textField;
 716                 } else {
 717                         wfProfileOut( __METHOD__ );
 718                         return false;
 719                 }
 720
 721                 # Use external methods for external objects, text in table is URL-only then
 722                 if ( in_array( 'external', $flags ) ) {
 723                         $url = $text;
 724                         @list(/* $proto */, $path ) = explode( '://', $url, 2 );
 725                         if( $path == '' ) {
 726                                 wfProfileOut( __METHOD__ );
 727                                 return false;
 728                         }
 729                         $text = ExternalStore::fetchFromURL( $url );
 730                 }
 731
 732                 // If the text was fetched without an error, convert it
 733                 if ( $text !== false ) {
 734                         if( in_array( 'gzip', $flags ) ) {
 735                                 # Deal with optional compression of archived pages.
 736                                 # This can be done periodically via maintenance/compressOld.php, and
 737                                 # as pages are saved if $wgCompressRevisions is set.
 738                                 $text = gzinflate( $text );
 739                         }
 740
 741                         if( in_array( 'object', $flags ) ) {
 742                                 # Generic compressed storage
 743                                 $obj = unserialize( $text );
 744                                 if ( !is_object( $obj ) ) {
 745                                         // Invalid object
 746                                         wfProfileOut( __METHOD__ );
 747                                         return false;
 748                                 }
 749                                 $text = $obj->getText();
 750                         }
 751
 752                         global $wgLegacyEncoding;
 753                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) ) {
 754                                 # Old revisions kept around in a legacy encoding?
 755                                 # Upconvert on demand.
 756                                 # ("utf8" checked for compatibility with some broken
 757                                 #  conversion scripts 2008-12-30)
 758                                 global $wgInputEncoding, $wgContLang;
 759                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 760                         }
 761                 }
 762                 wfProfileOut( __METHOD__ );
 763                 return $text;
 764         }
 765
 766         /**
 767          * If $wgCompressRevisions is enabled, we will compress data.
 768          * The input string is modified in place.
 769          * Return value is the flags field: contains 'gzip' if the
 770          * data is compressed, and 'utf-8' if we're saving in UTF-8
 771          * mode.
 772          *
 773          * @param $text Mixed: reference to a text
 774          * @return String
 775          */
 776         public static function compressRevisionText( &$text ) {
 777                 global $wgCompressRevisions;
 778                 $flags = array();
 779
 780                 # Revisions not marked this way will be converted
 781                 # on load if $wgLegacyCharset is set in the future.
 782                 $flags[] = 'utf-8';
 783
 784                 if( $wgCompressRevisions ) {
 785                         if( function_exists( 'gzdeflate' ) ) {
 786                                 $text = gzdeflate( $text );
 787                                 $flags[] = 'gzip';
 788                         } else {
 789                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 790                         }
 791                 }
 792                 return implode( ',', $flags );
 793         }
 794
 795         /**
 796          * Insert a new revision into the database, returning the new revision ID
 797          * number on success and dies horribly on failure.
 798          *
 799          * @param $dbw DatabaseBase (master connection)
 800          * @return Integer
 801          */
 802         public function insertOn( $dbw ) {
 803                 global $wgDefaultExternalStore;
 804
 805                 wfProfileIn( __METHOD__ );
 806
 807                 $data = $this->mText;
 808                 $flags = Revision::compressRevisionText( $data );
 809
 810                 # Write to external storage if required
 811                 if( $wgDefaultExternalStore ) {
 812                         // Store and get the URL
 813                         $data = ExternalStore::insertToDefault( $data );
 814                         if( !$data ) {
 815                                 throw new MWException( "Unable to store text to external storage" );
 816                         }
 817                         if( $flags ) {
 818                                 $flags .= ',';
 819                         }
 820                         $flags .= 'external';
 821                 }
 822
 823                 # Record the text (or external storage URL) to the text table
 824                 if( !isset( $this->mTextId ) ) {
 825                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 826                         $dbw->insert( 'text',
 827                                 array(
 828                                         'old_id'    => $old_id,
 829                                         'old_text'  => $data,
 830                                         'old_flags' => $flags,
 831                                 ), __METHOD__
 832                         );
 833                         $this->mTextId = $dbw->insertId();
 834                 }
 835
 836                 # Record the edit in revisions
 837                 $rev_id = isset( $this->mId )
 838                         ? $this->mId
 839                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 840                 $dbw->insert( 'revision',
 841                         array(
 842                                 'rev_id'         => $rev_id,
 843                                 'rev_page'       => $this->mPage,
 844                                 'rev_text_id'    => $this->mTextId,
 845                                 'rev_comment'    => $this->mComment,
 846                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 847                                 'rev_user'       => $this->mUser,
 848                                 'rev_user_text'  => $this->mUserText,
 849                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 850                                 'rev_deleted'    => $this->mDeleted,
 851                                 'rev_len'        => $this->mSize,
 852                                 'rev_parent_id'  => is_null($this->mParentId) ?
 853                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 854                         ), __METHOD__
 855                 );
 856
 857                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 858
 859                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 860
 861                 wfProfileOut( __METHOD__ );
 862                 return $this->mId;
 863         }
 864
 865         /**
 866          * Lazy-load the revision's text.
 867          * Currently hardcoded to the 'text' table storage engine.
 868          *
 869          * @return String
 870          */
 871         protected function loadText() {
 872                 wfProfileIn( __METHOD__ );
 873
 874                 // Caching may be beneficial for massive use of external storage
 875                 global $wgRevisionCacheExpiry, $wgMemc;
 876                 $textId = $this->getTextId();
 877                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 878                 if( $wgRevisionCacheExpiry ) {
 879                         $text = $wgMemc->get( $key );
 880                         if( is_string( $text ) ) {
 881                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 882                                 wfProfileOut( __METHOD__ );
 883                                 return $text;
 884                         }
 885                 }
 886
 887                 // If we kept data for lazy extraction, use it now...
 888                 if ( isset( $this->mTextRow ) ) {
 889                         $row = $this->mTextRow;
 890                         $this->mTextRow = null;
 891                 } else {
 892                         $row = null;
 893                 }
 894
 895                 if( !$row ) {
 896                         // Text data is immutable; check slaves first.
 897                         $dbr = wfGetDB( DB_SLAVE );
 898                         $row = $dbr->selectRow( 'text',
 899                                 array( 'old_text', 'old_flags' ),
 900                                 array( 'old_id' => $this->getTextId() ),
 901                                 __METHOD__ );
 902                 }
 903
 904                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 905                         // Possible slave lag!
 906                         $dbw = wfGetDB( DB_MASTER );
 907                         $row = $dbw->selectRow( 'text',
 908                                 array( 'old_text', 'old_flags' ),
 909                                 array( 'old_id' => $this->getTextId() ),
 910                                 __METHOD__ );
 911                 }
 912
 913                 $text = self::getRevisionText( $row );
 914
 915                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 916                 if( $wgRevisionCacheExpiry && $text !== false ) {
 917                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 918                 }
 919
 920                 wfProfileOut( __METHOD__ );
 921
 922                 return $text;
 923         }
 924
 925         /**
 926          * Create a new null-revision for insertion into a page's
 927          * history. This will not re-save the text, but simply refer
 928          * to the text from the previous version.
 929          *
 930          * Such revisions can for instance identify page rename
 931          * operations and other such meta-modifications.
 932          *
 933          * @param $dbw DatabaseBase
 934          * @param $pageId Integer: ID number of the page to read from
 935          * @param $summary String: revision's summary
 936          * @param $minor Boolean: whether the revision should be considered as minor
 937          * @return Mixed: Revision, or null on error
 938          */
 939         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 940                 wfProfileIn( __METHOD__ );
 941
 942                 $current = $dbw->selectRow(
 943                         array( 'page', 'revision' ),
 944                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 945                         array(
 946                                 'page_id' => $pageId,
 947                                 'page_latest=rev_id',
 948                                 ),
 949                         __METHOD__ );
 950
 951                 if( $current ) {
 952                         $revision = new Revision( array(
 953                                 'page'       => $pageId,
 954                                 'comment'    => $summary,
 955                                 'minor_edit' => $minor,
 956                                 'text_id'    => $current->rev_text_id,
 957                                 'parent_id'  => $current->page_latest,
 958                                 'len'        => $current->rev_len
 959                                 ) );
 960                 } else {
 961                         $revision = null;
 962                 }
 963
 964                 wfProfileOut( __METHOD__ );
 965                 return $revision;
 966         }
 967
 968         /**
 969          * Determine if the current user is allowed to view a particular
 970          * field of this revision, if it's marked as deleted.
 971          *
 972          * @param $field Integer:one of self::DELETED_TEXT,
 973          *                              self::DELETED_COMMENT,
 974          *                              self::DELETED_USER
 975          * @return Boolean
 976          */
 977         public function userCan( $field ) {
 978                 return self::userCanBitfield( $this->mDeleted, $field );
 979         }
 980
 981         /**
 982          * Determine if the current user is allowed to view a particular
 983          * field of this revision, if it's marked as deleted. This is used
 984          * by various classes to avoid duplication.
 985          *
 986          * @param $bitfield Integer: current field
 987          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
 988          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
 989          *                               self::DELETED_USER = File::DELETED_USER
 990          * @return Boolean
 991          */
 992         public static function userCanBitfield( $bitfield, $field ) {
 993                 if( $bitfield & $field ) { // aspect is deleted
 994                         global $wgUser;
 995                         $permission = '';
 996                         if ( $bitfield & self::DELETED_RESTRICTED ) {
 997                                 $permission = 'suppressrevision';
 998                         } elseif ( $field & self::DELETED_TEXT ) {
 999                                 $permission = 'deletedtext';
1000                         } else {
1001                                 $permission = 'deletedhistory';
1002                         }
1003                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1004                         return $wgUser->isAllowed( $permission );
1005                 } else {
1006                         return true;
1007                 }
1008         }
1009
1010         /**
1011          * Get rev_timestamp from rev_id, without loading the rest of the row
1012          *
1013          * @param $title Title
1014          * @param $id Integer
1015          * @return String
1016          */
1017         static function getTimestampFromId( $title, $id ) {
1018                 $dbr = wfGetDB( DB_SLAVE );
1019                 // Casting fix for DB2
1020                 if ( $id == '' ) {
1021                         $id = 0;
1022                 }
1023                 $conds = array( 'rev_id' => $id );
1024                 $conds['rev_page'] = $title->getArticleId();
1025                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1026                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1027                         # Not in slave, try master
1028                         $dbw = wfGetDB( DB_MASTER );
1029                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1030                 }
1031                 return wfTimestamp( TS_MW, $timestamp );
1032         }
1033
1034         /**
1035          * Get count of revisions per page...not very efficient
1036          *
1037          * @param $db DatabaseBase
1038          * @param $id Integer: page id
1039          * @return Integer
1040          */
1041         static function countByPageId( $db, $id ) {
1042                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1043                         array( 'rev_page' => $id ), __METHOD__ );
1044                 if( $row ) {
1045                         return $row->revCount;
1046                 }
1047                 return 0;
1048         }
1049
1050         /**
1051          * Get count of revisions per page...not very efficient
1052          *
1053          * @param $db DatabaseBase
1054          * @param $title Title
1055          * @return Integer
1056          */
1057         static function countByTitle( $db, $title ) {
1058                 $id = $title->getArticleId();
1059                 if( $id ) {
1060                         return Revision::countByPageId( $db, $id );
1061                 }
1062                 return 0;
1063         }
1064 }
1065
1066 /**
1067  * Aliases for backwards compatibility with 1.6
1068  */
1069 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1070 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1071 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1072 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );