includes/Revision.php

   1 <?php
   2 /**
   3  * Representation of a page version.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * @todo document
  25  */
  26 class Revision implements IDBAccessObject {
  27         protected $mId;
  28
  29         /**
  30          * @var int|null
  31          */
  32         protected $mPage;
  33         protected $mUserText;
  34         protected $mOrigUserText;
  35         protected $mUser;
  36         protected $mMinorEdit;
  37         protected $mTimestamp;
  38         protected $mDeleted;
  39         protected $mSize;
  40         protected $mSha1;
  41         protected $mParentId;
  42         protected $mComment;
  43         protected $mText;
  44         protected $mTextRow;
  45
  46         /**
  47          * @var null|Title
  48          */
  49         protected $mTitle;
  50         protected $mCurrent;
  51         protected $mContentModel;
  52         protected $mContentFormat;
  53
  54         /**
  55          * @var Content|null|bool
  56          */
  57         protected $mContent;
  58
  59         /**
  60          * @var null|ContentHandler
  61          */
  62         protected $mContentHandler;
  63
  64         // Revision deletion constants
  65         const DELETED_TEXT = 1;
  66         const DELETED_COMMENT = 2;
  67         const DELETED_USER = 4;
  68         const DELETED_RESTRICTED = 8;
  69         const SUPPRESSED_USER = 12; // convenience
  70
  71         // Audience options for accessors
  72         const FOR_PUBLIC = 1;
  73         const FOR_THIS_USER = 2;
  74         const RAW = 3;
  75
  76         /**
  77          * Load a page revision from a given revision ID number.
  78          * Returns null if no such revision can be found.
  79          *
  80          * $flags include:
  81          *      Revision::READ_LATEST  : Select the data from the master
  82          *      Revision::READ_LOCKING : Select & lock the data from the master
  83          *
  84          * @param $id Integer
  85          * @param $flags Integer (optional)
  86          * @return Revision or null
  87          */
  88         public static function newFromId( $id, $flags = 0 ) {
  89                 return self::newFromConds( array( 'rev_id' => intval( $id ) ), $flags );
  90         }
  91
  92         /**
  93          * Load either the current, or a specified, revision
  94          * that's attached to a given title. If not attached
  95          * to that title, will return null.
  96          *
  97          * $flags include:
  98          *      Revision::READ_LATEST  : Select the data from the master
  99          *      Revision::READ_LOCKING : Select & lock the data from the master
 100          *
 101          * @param $title Title
 102          * @param $id Integer (optional)
 103          * @param $flags Integer Bitfield (optional)
 104          * @return Revision or null
 105          */
 106         public static function newFromTitle( $title, $id = 0, $flags = 0 ) {
 107                 $conds = array(
 108                         'page_namespace' => $title->getNamespace(),
 109                         'page_title'     => $title->getDBkey()
 110                 );
 111                 if ( $id ) {
 112                         // Use the specified ID
 113                         $conds['rev_id'] = $id;
 114                 } else {
 115                         // Use a join to get the latest revision
 116                         $conds[] = 'rev_id=page_latest';
 117                 }
 118                 return self::newFromConds( $conds, (int)$flags );
 119         }
 120
 121         /**
 122          * Load either the current, or a specified, revision
 123          * that's attached to a given page ID.
 124          * Returns null if no such revision can be found.
 125          *
 126          * $flags include:
 127          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 128          *      Revision::READ_LOCKING : Select & lock the data from the master
 129          *
 130          * @param $revId Integer
 131          * @param $pageId Integer (optional)
 132          * @param $flags Integer Bitfield (optional)
 133          * @return Revision or null
 134          */
 135         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 136                 $conds = array( 'page_id' => $pageId );
 137                 if ( $revId ) {
 138                         $conds['rev_id'] = $revId;
 139                 } else {
 140                         // Use a join to get the latest revision
 141                         $conds[] = 'rev_id = page_latest';
 142                 }
 143                 return self::newFromConds( $conds, (int)$flags );
 144         }
 145
 146         /**
 147          * Make a fake revision object from an archive table row. This is queried
 148          * for permissions or even inserted (as in Special:Undelete)
 149          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 150          *
 151          * @param $row
 152          * @param $overrides array
 153          *
 154          * @throws MWException
 155          * @return Revision
 156          */
 157         public static function newFromArchiveRow( $row, $overrides = array() ) {
 158                 global $wgContentHandlerUseDB;
 159
 160                 $attribs = $overrides + array(
 161                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 162                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 163                         'comment'    => $row->ar_comment,
 164                         'user'       => $row->ar_user,
 165                         'user_text'  => $row->ar_user_text,
 166                         'timestamp'  => $row->ar_timestamp,
 167                         'minor_edit' => $row->ar_minor_edit,
 168                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 169                         'deleted'    => $row->ar_deleted,
 170                         'len'        => $row->ar_len,
 171                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 172                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 173                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 174                 );
 175
 176                 if ( !$wgContentHandlerUseDB ) {
 177                         unset( $attribs['content_model'] );
 178                         unset( $attribs['content_format'] );
 179                 }
 180
 181                 if ( !isset( $attribs['title'] )
 182                         && isset( $row->ar_namespace )
 183                         && isset( $row->ar_title ) ) {
 184
 185                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 186                 }
 187
 188                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 189                         // Pre-1.5 ar_text row
 190                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 191                         if ( $attribs['text'] === false ) {
 192                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 193                         }
 194                 }
 195                 return new self( $attribs );
 196         }
 197
 198         /**
 199          * @since 1.19
 200          *
 201          * @param $row
 202          * @return Revision
 203          */
 204         public static function newFromRow( $row ) {
 205                 return new self( $row );
 206         }
 207
 208         /**
 209          * Load a page revision from a given revision ID number.
 210          * Returns null if no such revision can be found.
 211          *
 212          * @param $db DatabaseBase
 213          * @param $id Integer
 214          * @return Revision or null
 215          */
 216         public static function loadFromId( $db, $id ) {
 217                 return self::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 218         }
 219
 220         /**
 221          * Load either the current, or a specified, revision
 222          * that's attached to a given page. If not attached
 223          * to that page, will return null.
 224          *
 225          * @param $db DatabaseBase
 226          * @param $pageid Integer
 227          * @param $id Integer
 228          * @return Revision or null
 229          */
 230         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 231                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 232                 if( $id ) {
 233                         $conds['rev_id'] = intval( $id );
 234                 } else {
 235                         $conds[] = 'rev_id=page_latest';
 236                 }
 237                 return self::loadFromConds( $db, $conds );
 238         }
 239
 240         /**
 241          * Load either the current, or a specified, revision
 242          * that's attached to a given page. If not attached
 243          * to that page, will return null.
 244          *
 245          * @param $db DatabaseBase
 246          * @param $title Title
 247          * @param $id Integer
 248          * @return Revision or null
 249          */
 250         public static function loadFromTitle( $db, $title, $id = 0 ) {
 251                 if( $id ) {
 252                         $matchId = intval( $id );
 253                 } else {
 254                         $matchId = 'page_latest';
 255                 }
 256                 return self::loadFromConds( $db,
 257                         array(
 258                                 "rev_id=$matchId",
 259                                 'page_namespace' => $title->getNamespace(),
 260                                 'page_title'     => $title->getDBkey()
 261                         )
 262                 );
 263         }
 264
 265         /**
 266          * Load the revision for the given title with the given timestamp.
 267          * WARNING: Timestamps may in some circumstances not be unique,
 268          * so this isn't the best key to use.
 269          *
 270          * @param $db DatabaseBase
 271          * @param $title Title
 272          * @param $timestamp String
 273          * @return Revision or null
 274          */
 275         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 276                 return self::loadFromConds( $db,
 277                         array(
 278                                 'rev_timestamp'  => $db->timestamp( $timestamp ),
 279                                 'page_namespace' => $title->getNamespace(),
 280                                 'page_title'     => $title->getDBkey()
 281                         )
 282                 );
 283         }
 284
 285         /**
 286          * Given a set of conditions, fetch a revision.
 287          *
 288          * @param $conditions Array
 289          * @param $flags integer (optional)
 290          * @return Revision or null
 291          */
 292         private static function newFromConds( $conditions, $flags = 0 ) {
 293                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 294                 $rev = self::loadFromConds( $db, $conditions, $flags );
 295                 if ( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 296                         if ( !( $flags & self::READ_LATEST ) ) {
 297                                 $dbw = wfGetDB( DB_MASTER );
 298                                 $rev = self::loadFromConds( $dbw, $conditions, $flags );
 299                         }
 300                 }
 301                 return $rev;
 302         }
 303
 304         /**
 305          * Given a set of conditions, fetch a revision from
 306          * the given database connection.
 307          *
 308          * @param $db DatabaseBase
 309          * @param $conditions Array
 310          * @param $flags integer (optional)
 311          * @return Revision or null
 312          */
 313         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 314                 $res = self::fetchFromConds( $db, $conditions, $flags );
 315                 if( $res ) {
 316                         $row = $res->fetchObject();
 317                         if( $row ) {
 318                                 $ret = new Revision( $row );
 319                                 return $ret;
 320                         }
 321                 }
 322                 $ret = null;
 323                 return $ret;
 324         }
 325
 326         /**
 327          * Return a wrapper for a series of database rows to
 328          * fetch all of a given page's revisions in turn.
 329          * Each row can be fed to the constructor to get objects.
 330          *
 331          * @param $title Title
 332          * @return ResultWrapper
 333          */
 334         public static function fetchRevision( $title ) {
 335                 return self::fetchFromConds(
 336                         wfGetDB( DB_SLAVE ),
 337                         array(
 338                                 'rev_id=page_latest',
 339                                 'page_namespace' => $title->getNamespace(),
 340                                 'page_title'     => $title->getDBkey()
 341                         )
 342                 );
 343         }
 344
 345         /**
 346          * Given a set of conditions, return a ResultWrapper
 347          * which will return matching database rows with the
 348          * fields necessary to build Revision objects.
 349          *
 350          * @param $db DatabaseBase
 351          * @param $conditions Array
 352          * @param $flags integer (optional)
 353          * @return ResultWrapper
 354          */
 355         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 356                 $fields = array_merge(
 357                         self::selectFields(),
 358                         self::selectPageFields(),
 359                         self::selectUserFields()
 360                 );
 361                 $options = array( 'LIMIT' => 1 );
 362                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 363                         $options[] = 'FOR UPDATE';
 364                 }
 365                 return $db->select(
 366                         array( 'revision', 'page', 'user' ),
 367                         $fields,
 368                         $conditions,
 369                         __METHOD__,
 370                         $options,
 371                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 372                 );
 373         }
 374
 375         /**
 376          * Return the value of a select() JOIN conds array for the user table.
 377          * This will get user table rows for logged-in users.
 378          * @since 1.19
 379          * @return Array
 380          */
 381         public static function userJoinCond() {
 382                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 383         }
 384
 385         /**
 386          * Return the value of a select() page conds array for the page table.
 387          * This will assure that the revision(s) are not orphaned from live pages.
 388          * @since 1.19
 389          * @return Array
 390          */
 391         public static function pageJoinCond() {
 392                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 393         }
 394
 395         /**
 396          * Return the list of revision fields that should be selected to create
 397          * a new revision.
 398          * @return array
 399          */
 400         public static function selectFields() {
 401                 global $wgContentHandlerUseDB;
 402
 403                 $fields = array(
 404                         'rev_id',
 405                         'rev_page',
 406                         'rev_text_id',
 407                         'rev_timestamp',
 408                         'rev_comment',
 409                         'rev_user_text',
 410                         'rev_user',
 411                         'rev_minor_edit',
 412                         'rev_deleted',
 413                         'rev_len',
 414                         'rev_parent_id',
 415                         'rev_sha1',
 416                 );
 417
 418                 if ( $wgContentHandlerUseDB ) {
 419                         $fields[] = 'rev_content_format';
 420                         $fields[] = 'rev_content_model';
 421                 }
 422
 423                 return $fields;
 424         }
 425
 426         /**
 427          * Return the list of text fields that should be selected to read the
 428          * revision text
 429          * @return array
 430          */
 431         public static function selectTextFields() {
 432                 return array(
 433                         'old_text',
 434                         'old_flags'
 435                 );
 436         }
 437
 438         /**
 439          * Return the list of page fields that should be selected from page table
 440          * @return array
 441          */
 442         public static function selectPageFields() {
 443                 return array(
 444                         'page_namespace',
 445                         'page_title',
 446                         'page_id',
 447                         'page_latest',
 448                         'page_is_redirect',
 449                         'page_len',
 450                 );
 451         }
 452
 453         /**
 454          * Return the list of user fields that should be selected from user table
 455          * @return array
 456          */
 457         public static function selectUserFields() {
 458                 return array( 'user_name' );
 459         }
 460
 461         /**
 462          * Do a batched query to get the parent revision lengths
 463          * @param $db DatabaseBase
 464          * @param $revIds Array
 465          * @return array
 466          */
 467         public static function getParentLengths( $db, array $revIds ) {
 468                 $revLens = array();
 469                 if ( !$revIds ) {
 470                         return $revLens; // empty
 471                 }
 472                 wfProfileIn( __METHOD__ );
 473                 $res = $db->select( 'revision',
 474                         array( 'rev_id', 'rev_len' ),
 475                         array( 'rev_id' => $revIds ),
 476                         __METHOD__ );
 477                 foreach ( $res as $row ) {
 478                         $revLens[$row->rev_id] = $row->rev_len;
 479                 }
 480                 wfProfileOut( __METHOD__ );
 481                 return $revLens;
 482         }
 483
 484         /**
 485          * Constructor
 486          *
 487          * @param $row Mixed: either a database row or an array
 488          * @throws MWException
 489          * @access private
 490          */
 491         function __construct( $row ) {
 492                 if( is_object( $row ) ) {
 493                         $this->mId        = intval( $row->rev_id );
 494                         $this->mPage      = intval( $row->rev_page );
 495                         $this->mTextId    = intval( $row->rev_text_id );
 496                         $this->mComment   =         $row->rev_comment;
 497                         $this->mUser      = intval( $row->rev_user );
 498                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 499                         $this->mTimestamp =         $row->rev_timestamp;
 500                         $this->mDeleted   = intval( $row->rev_deleted );
 501
 502                         if ( !isset( $row->rev_parent_id ) ) {
 503                                 $this->mParentId = null;
 504                         } else {
 505                                 $this->mParentId = intval( $row->rev_parent_id );
 506                         }
 507
 508                         if ( !isset( $row->rev_len ) ) {
 509                                 $this->mSize = null;
 510                         } else {
 511                                 $this->mSize = intval( $row->rev_len );
 512                         }
 513
 514                         if ( !isset( $row->rev_sha1 ) ) {
 515                                 $this->mSha1 = null;
 516                         } else {
 517                                 $this->mSha1 = $row->rev_sha1;
 518                         }
 519
 520                         if( isset( $row->page_latest ) ) {
 521                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 522                                 $this->mTitle = Title::newFromRow( $row );
 523                         } else {
 524                                 $this->mCurrent = false;
 525                                 $this->mTitle = null;
 526                         }
 527
 528                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 529                                 $this->mContentModel = null; # determine on demand if needed
 530                         } else {
 531                                 $this->mContentModel = strval( $row->rev_content_model );
 532                         }
 533
 534                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 535                                 $this->mContentFormat = null; # determine on demand if needed
 536                         } else {
 537                                 $this->mContentFormat = strval( $row->rev_content_format );
 538                         }
 539
 540                         // Lazy extraction...
 541                         $this->mText = null;
 542                         if( isset( $row->old_text ) ) {
 543                                 $this->mTextRow = $row;
 544                         } else {
 545                                 // 'text' table row entry will be lazy-loaded
 546                                 $this->mTextRow = null;
 547                         }
 548
 549                         // Use user_name for users and rev_user_text for IPs...
 550                         $this->mUserText = null; // lazy load if left null
 551                         if ( $this->mUser == 0 ) {
 552                                 $this->mUserText = $row->rev_user_text; // IP user
 553                         } elseif ( isset( $row->user_name ) ) {
 554                                 $this->mUserText = $row->user_name; // logged-in user
 555                         }
 556                         $this->mOrigUserText = $row->rev_user_text;
 557                 } elseif( is_array( $row ) ) {
 558                         // Build a new revision to be saved...
 559                         global $wgUser; // ugh
 560
 561                         # if we have a content object, use it to set the model and type
 562                         if ( !empty( $row['content'] ) ) {
 563                                 //@todo: when is that set? test with external store setup! check out insertOn() [dk]
 564                                 if ( !empty( $row['text_id'] ) ) {
 565                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 566                                                 "can't serialize content object" );
 567                                 }
 568
 569                                 $row['content_model'] = $row['content']->getModel();
 570                                 # note: mContentFormat is initializes later accordingly
 571                                 # note: content is serialized later in this method!
 572                                 # also set text to null?
 573                         }
 574
 575                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 576                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 577                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 578                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 579                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 580                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 581                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 582                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 583                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 584                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 585                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 586
 587                         $this->mContentModel   = isset( $row['content_model']  )  ? strval( $row['content_model'] )  : null;
 588                         $this->mContentFormat  = isset( $row['content_format']  ) ? strval( $row['content_format'] ) : null;
 589
 590                         // Enforce spacing trimming on supplied text
 591                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 592                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 593                         $this->mTextRow   = null;
 594
 595                         $this->mTitle     = isset( $row['title']      ) ? $row['title'] : null;
 596
 597                         // if we have a Content object, override mText and mContentModel
 598                         if ( !empty( $row['content'] ) ) {
 599                                 if ( !( $row['content'] instanceof Content ) ) {
 600                                         throw new MWException( '`content` field must contain a Content object.' );
 601                                 }
 602
 603                                 $handler = $this->getContentHandler();
 604                                 $this->mContent = $row['content'];
 605
 606                                 $this->mContentModel = $this->mContent->getModel();
 607                                 $this->mContentHandler = null;
 608
 609                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 610                         } elseif ( !is_null( $this->mText ) ) {
 611                                 $handler = $this->getContentHandler();
 612                                 $this->mContent = $handler->unserializeContent( $this->mText );
 613                         }
 614
 615                         // If we have a Title object, make sure it is consistent with mPage.
 616                         if ( $this->mTitle && $this->mTitle->exists() ) {
 617                                 if ( $this->mPage === null ) {
 618                                         // if the page ID wasn't known, set it now
 619                                         $this->mPage = $this->mTitle->getArticleID();
 620                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 621                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 622                                         // but it seems worth mentioning it in the log.
 623                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 624                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 625                                 }
 626                         }
 627
 628                         $this->mCurrent = false;
 629
 630                         // If we still have no length, see it we have the text to figure it out
 631                         if ( !$this->mSize ) {
 632                                 if ( !is_null( $this->mContent ) ) {
 633                                         $this->mSize = $this->mContent->getSize();
 634                                 } else {
 635                                         #NOTE: this should never happen if we have either text or content object!
 636                                         $this->mSize = null;
 637                                 }
 638                         }
 639
 640                         // Same for sha1
 641                         if ( $this->mSha1 === null ) {
 642                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 643                         }
 644
 645                         // force lazy init
 646                         $this->getContentModel();
 647                         $this->getContentFormat();
 648                 } else {
 649                         throw new MWException( 'Revision constructor passed invalid row format.' );
 650                 }
 651                 $this->mUnpatrolled = null;
 652         }
 653
 654         /**
 655          * Get revision ID
 656          *
 657          * @return Integer|null
 658          */
 659         public function getId() {
 660                 return $this->mId;
 661         }
 662
 663         /**
 664          * Set the revision ID
 665          *
 666          * @since 1.19
 667          * @param $id Integer
 668          */
 669         public function setId( $id ) {
 670                 $this->mId = $id;
 671         }
 672
 673         /**
 674          * Get text row ID
 675          *
 676          * @return Integer|null
 677          */
 678         public function getTextId() {
 679                 return $this->mTextId;
 680         }
 681
 682         /**
 683          * Get parent revision ID (the original previous page revision)
 684          *
 685          * @return Integer|null
 686          */
 687         public function getParentId() {
 688                 return $this->mParentId;
 689         }
 690
 691         /**
 692          * Returns the length of the text in this revision, or null if unknown.
 693          *
 694          * @return Integer|null
 695          */
 696         public function getSize() {
 697                 return $this->mSize;
 698         }
 699
 700         /**
 701          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 702          *
 703          * @return String|null
 704          */
 705         public function getSha1() {
 706                 return $this->mSha1;
 707         }
 708
 709         /**
 710          * Returns the title of the page associated with this entry or null.
 711          *
 712          * Will do a query, when title is not set and id is given.
 713          *
 714          * @return Title|null
 715          */
 716         public function getTitle() {
 717                 if( isset( $this->mTitle ) ) {
 718                         return $this->mTitle;
 719                 }
 720                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 721                         $dbr = wfGetDB( DB_SLAVE );
 722                         $row = $dbr->selectRow(
 723                                 array( 'page', 'revision' ),
 724                                 self::selectPageFields(),
 725                                 array( 'page_id=rev_page',
 726                                         'rev_id' => $this->mId ),
 727                                 __METHOD__ );
 728                         if ( $row ) {
 729                                 $this->mTitle = Title::newFromRow( $row );
 730                         }
 731                 }
 732
 733                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 734                         $this->mTitle = Title::newFromID( $this->mPage );
 735                 }
 736
 737                 return $this->mTitle;
 738         }
 739
 740         /**
 741          * Set the title of the revision
 742          *
 743          * @param $title Title
 744          */
 745         public function setTitle( $title ) {
 746                 $this->mTitle = $title;
 747         }
 748
 749         /**
 750          * Get the page ID
 751          *
 752          * @return Integer|null
 753          */
 754         public function getPage() {
 755                 return $this->mPage;
 756         }
 757
 758         /**
 759          * Fetch revision's user id if it's available to the specified audience.
 760          * If the specified audience does not have access to it, zero will be
 761          * returned.
 762          *
 763          * @param $audience Integer: one of:
 764          *      Revision::FOR_PUBLIC       to be displayed to all users
 765          *      Revision::FOR_THIS_USER    to be displayed to the given user
 766          *      Revision::RAW              get the ID regardless of permissions
 767          * @param $user User object to check for, only if FOR_THIS_USER is passed
 768          *              to the $audience parameter
 769          * @return Integer
 770          */
 771         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 772                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 773                         return 0;
 774                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 775                         return 0;
 776                 } else {
 777                         return $this->mUser;
 778                 }
 779         }
 780
 781         /**
 782          * Fetch revision's user id without regard for the current user's permissions
 783          *
 784          * @return String
 785          */
 786         public function getRawUser() {
 787                 return $this->mUser;
 788         }
 789
 790         /**
 791          * Fetch revision's username if it's available to the specified audience.
 792          * If the specified audience does not have access to the username, an
 793          * empty string will be returned.
 794          *
 795          * @param $audience Integer: one of:
 796          *      Revision::FOR_PUBLIC       to be displayed to all users
 797          *      Revision::FOR_THIS_USER    to be displayed to the given user
 798          *      Revision::RAW              get the text regardless of permissions
 799          * @param $user User object to check for, only if FOR_THIS_USER is passed
 800          *              to the $audience parameter
 801          * @return string
 802          */
 803         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 804                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 805                         return '';
 806                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 807                         return '';
 808                 } else {
 809                         return $this->getRawUserText();
 810                 }
 811         }
 812
 813         /**
 814          * Fetch revision's username without regard for view restrictions
 815          *
 816          * @return String
 817          */
 818         public function getRawUserText() {
 819                 if ( $this->mUserText === null ) {
 820                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 821                         if ( $this->mUserText === false ) {
 822                                 # This shouldn't happen, but it can if the wiki was recovered
 823                                 # via importing revs and there is no user table entry yet.
 824                                 $this->mUserText = $this->mOrigUserText;
 825                         }
 826                 }
 827                 return $this->mUserText;
 828         }
 829
 830         /**
 831          * Fetch revision comment if it's available to the specified audience.
 832          * If the specified audience does not have access to the comment, an
 833          * empty string will be returned.
 834          *
 835          * @param $audience Integer: one of:
 836          *      Revision::FOR_PUBLIC       to be displayed to all users
 837          *      Revision::FOR_THIS_USER    to be displayed to the given user
 838          *      Revision::RAW              get the text regardless of permissions
 839          * @param $user User object to check for, only if FOR_THIS_USER is passed
 840          *              to the $audience parameter
 841          * @return String
 842          */
 843         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 844                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 845                         return '';
 846                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 847                         return '';
 848                 } else {
 849                         return $this->mComment;
 850                 }
 851         }
 852
 853         /**
 854          * Fetch revision comment without regard for the current user's permissions
 855          *
 856          * @return String
 857          */
 858         public function getRawComment() {
 859                 return $this->mComment;
 860         }
 861
 862         /**
 863          * @return Boolean
 864          */
 865         public function isMinor() {
 866                 return (bool)$this->mMinorEdit;
 867         }
 868
 869         /**
 870          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 871          */
 872         public function isUnpatrolled() {
 873                 if( $this->mUnpatrolled !== null ) {
 874                         return $this->mUnpatrolled;
 875                 }
 876                 $dbr = wfGetDB( DB_SLAVE );
 877                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 878                         'rc_id',
 879                         array( // Add redundant user,timestamp condition so we can use the existing index
 880                                 'rc_user_text'  => $this->getRawUserText(),
 881                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 882                                 'rc_this_oldid' => $this->getId(),
 883                                 'rc_patrolled'  => 0
 884                         ),
 885                         __METHOD__
 886                 );
 887                 return (int)$this->mUnpatrolled;
 888         }
 889
 890         /**
 891          * @param int $field one of DELETED_* bitfield constants
 892          *
 893          * @return Boolean
 894          */
 895         public function isDeleted( $field ) {
 896                 return ( $this->mDeleted & $field ) == $field;
 897         }
 898
 899         /**
 900          * Get the deletion bitfield of the revision
 901          *
 902          * @return int
 903          */
 904         public function getVisibility() {
 905                 return (int)$this->mDeleted;
 906         }
 907
 908         /**
 909          * Fetch revision text if it's available to the specified audience.
 910          * If the specified audience does not have the ability to view this
 911          * revision, an empty string will be returned.
 912          *
 913          * @param $audience Integer: one of:
 914          *      Revision::FOR_PUBLIC       to be displayed to all users
 915          *      Revision::FOR_THIS_USER    to be displayed to the given user
 916          *      Revision::RAW              get the text regardless of permissions
 917          * @param $user User object to check for, only if FOR_THIS_USER is passed
 918          *              to the $audience parameter
 919          *
 920          * @deprecated in 1.21, use getContent() instead
 921          * @todo: replace usage in core
 922          * @return String
 923          */
 924         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 925                 ContentHandler::deprecated( __METHOD__, '1.21' );
 926
 927                 $content = $this->getContent( $audience, $user );
 928                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 929         }
 930
 931         /**
 932          * Fetch revision content if it's available to the specified audience.
 933          * If the specified audience does not have the ability to view this
 934          * revision, null will be returned.
 935          *
 936          * @param $audience Integer: one of:
 937          *      Revision::FOR_PUBLIC       to be displayed to all users
 938          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 939          *      Revision::RAW              get the text regardless of permissions
 940          * @param $user User object to check for, only if FOR_THIS_USER is passed
 941          *              to the $audience parameter
 942          * @since 1.21
 943          * @return Content|null
 944          */
 945         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 946                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 947                         return null;
 948                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 949                         return null;
 950                 } else {
 951                         return $this->getContentInternal();
 952                 }
 953         }
 954
 955         /**
 956          * Alias for getText(Revision::FOR_THIS_USER)
 957          *
 958          * @deprecated since 1.17
 959          * @return String
 960          */
 961         public function revText() {
 962                 wfDeprecated( __METHOD__, '1.17' );
 963                 return $this->getText( self::FOR_THIS_USER );
 964         }
 965
 966         /**
 967          * Fetch revision text without regard for view restrictions
 968          *
 969          * @return String
 970          *
 971          * @deprecated since 1.21. Instead, use Revision::getContent( Revision::RAW )
 972          *                         or Revision::getSerializedData() as appropriate.
 973          */
 974         public function getRawText() {
 975                 ContentHandler::deprecated( __METHOD__, "1.21" );
 976                 return $this->getText( self::RAW );
 977         }
 978
 979         /**
 980          * Fetch original serialized data without regard for view restrictions
 981          *
 982          * @since 1.21
 983          * @return String
 984          */
 985         public function getSerializedData() {
 986                 return $this->mText;
 987         }
 988
 989         /**
 990          * Gets the content object for the revision (or null on failure).
 991          *
 992          * Note that for mutable Content objects, each call to this method will return a
 993          * fresh clone.
 994          *
 995          * @since 1.21
 996          * @return Content|null the Revision's content, or null on failure.
 997          */
 998         protected function getContentInternal() {
 999                 if( is_null( $this->mContent ) ) {
1000                         // Revision is immutable. Load on demand:
1001                         if( is_null( $this->mText ) ) {
1002                                 $this->mText = $this->loadText();
1003                         }
1004
1005                         if ( $this->mText !== null && $this->mText !== false ) {
1006                                 // Unserialize content
1007                                 $handler = $this->getContentHandler();
1008                                 $format = $this->getContentFormat();
1009
1010                                 $this->mContent = $handler->unserializeContent( $this->mText, $format );
1011                         } else {
1012                                 $this->mContent = false; // negative caching!
1013                         }
1014                 }
1015
1016                 // NOTE: copy() will return $this for immutable content objects
1017                 return $this->mContent ? $this->mContent->copy() : null;
1018         }
1019
1020         /**
1021          * Returns the content model for this revision.
1022          *
1023          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
1024          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1025          * is used as a last resort.
1026          *
1027          * @return String the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
1028          **/
1029         public function getContentModel() {
1030                 if ( !$this->mContentModel ) {
1031                         $title = $this->getTitle();
1032                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
1033
1034                         assert( !empty( $this->mContentModel ) );
1035                 }
1036
1037                 return $this->mContentModel;
1038         }
1039
1040         /**
1041          * Returns the content format for this revision.
1042          *
1043          * If no content format was stored in the database, the default format for this
1044          * revision's content model is returned.
1045          *
1046          * @return String the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
1047          **/
1048         public function getContentFormat() {
1049                 if ( !$this->mContentFormat ) {
1050                         $handler = $this->getContentHandler();
1051                         $this->mContentFormat = $handler->getDefaultFormat();
1052
1053                         assert( !empty( $this->mContentFormat ) );
1054                 }
1055
1056                 return $this->mContentFormat;
1057         }
1058
1059         /**
1060          * Returns the content handler appropriate for this revision's content model.
1061          *
1062          * @throws MWException
1063          * @return ContentHandler
1064          */
1065         public function getContentHandler() {
1066                 if ( !$this->mContentHandler ) {
1067                         $model = $this->getContentModel();
1068                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1069
1070                         $format = $this->getContentFormat();
1071
1072                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1073                                 throw new MWException( "Oops, the content format $format is not supported for this content model, $model" );
1074                         }
1075                 }
1076
1077                 return $this->mContentHandler;
1078         }
1079
1080         /**
1081          * @return String
1082          */
1083         public function getTimestamp() {
1084                 return wfTimestamp( TS_MW, $this->mTimestamp );
1085         }
1086
1087         /**
1088          * @return Boolean
1089          */
1090         public function isCurrent() {
1091                 return $this->mCurrent;
1092         }
1093
1094         /**
1095          * Get previous revision for this title
1096          *
1097          * @return Revision|null
1098          */
1099         public function getPrevious() {
1100                 if( $this->getTitle() ) {
1101                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1102                         if( $prev ) {
1103                                 return self::newFromTitle( $this->getTitle(), $prev );
1104                         }
1105                 }
1106                 return null;
1107         }
1108
1109         /**
1110          * Get next revision for this title
1111          *
1112          * @return Revision or null
1113          */
1114         public function getNext() {
1115                 if( $this->getTitle() ) {
1116                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1117                         if ( $next ) {
1118                                 return self::newFromTitle( $this->getTitle(), $next );
1119                         }
1120                 }
1121                 return null;
1122         }
1123
1124         /**
1125          * Get previous revision Id for this page_id
1126          * This is used to populate rev_parent_id on save
1127          *
1128          * @param $db DatabaseBase
1129          * @return Integer
1130          */
1131         private function getPreviousRevisionId( $db ) {
1132                 if( is_null( $this->mPage ) ) {
1133                         return 0;
1134                 }
1135                 # Use page_latest if ID is not given
1136                 if( !$this->mId ) {
1137                         $prevId = $db->selectField( 'page', 'page_latest',
1138                                 array( 'page_id' => $this->mPage ),
1139                                 __METHOD__ );
1140                 } else {
1141                         $prevId = $db->selectField( 'revision', 'rev_id',
1142                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1143                                 __METHOD__,
1144                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1145                 }
1146                 return intval( $prevId );
1147         }
1148
1149         /**
1150           * Get revision text associated with an old or archive row
1151           * $row is usually an object from wfFetchRow(), both the flags and the text
1152           * field must be included
1153           *
1154           * @param $row Object: the text data
1155           * @param string $prefix table prefix (default 'old_')
1156           * @param string|false $wiki the name of the wiki to load the revision text from
1157           *         (same as the the wiki $row was loaded from) or false to indicate the local
1158           *         wiki (this is the default). Otherwise, it must be a symbolic wiki database
1159           *         identifier as understood by the LoadBalancer class.
1160           * @return String: text the text requested or false on failure
1161           */
1162         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1163                 wfProfileIn( __METHOD__ );
1164
1165                 # Get data
1166                 $textField = $prefix . 'text';
1167                 $flagsField = $prefix . 'flags';
1168
1169                 if( isset( $row->$flagsField ) ) {
1170                         $flags = explode( ',', $row->$flagsField );
1171                 } else {
1172                         $flags = array();
1173                 }
1174
1175                 if( isset( $row->$textField ) ) {
1176                         $text = $row->$textField;
1177                 } else {
1178                         wfProfileOut( __METHOD__ );
1179                         return false;
1180                 }
1181
1182                 # Use external methods for external objects, text in table is URL-only then
1183                 if ( in_array( 'external', $flags ) ) {
1184                         $url = $text;
1185                         $parts = explode( '://', $url, 2 );
1186                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1187                                 wfProfileOut( __METHOD__ );
1188                                 return false;
1189                         }
1190                         $text = ExternalStore::fetchFromURL( $url, array( 'wiki' => $wiki ) );
1191                 }
1192
1193                 // If the text was fetched without an error, convert it
1194                 if ( $text !== false ) {
1195                         if( in_array( 'gzip', $flags ) ) {
1196                                 # Deal with optional compression of archived pages.
1197                                 # This can be done periodically via maintenance/compressOld.php, and
1198                                 # as pages are saved if $wgCompressRevisions is set.
1199                                 $text = gzinflate( $text );
1200                         }
1201
1202                         if( in_array( 'object', $flags ) ) {
1203                                 # Generic compressed storage
1204                                 $obj = unserialize( $text );
1205                                 if ( !is_object( $obj ) ) {
1206                                         // Invalid object
1207                                         wfProfileOut( __METHOD__ );
1208                                         return false;
1209                                 }
1210                                 $text = $obj->getText();
1211                         }
1212
1213                         global $wgLegacyEncoding;
1214                         if( $text !== false && $wgLegacyEncoding
1215                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1216                         {
1217                                 # Old revisions kept around in a legacy encoding?
1218                                 # Upconvert on demand.
1219                                 # ("utf8" checked for compatibility with some broken
1220                                 #  conversion scripts 2008-12-30)
1221                                 global $wgContLang;
1222                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1223                         }
1224                 }
1225                 wfProfileOut( __METHOD__ );
1226                 return $text;
1227         }
1228
1229         /**
1230          * If $wgCompressRevisions is enabled, we will compress data.
1231          * The input string is modified in place.
1232          * Return value is the flags field: contains 'gzip' if the
1233          * data is compressed, and 'utf-8' if we're saving in UTF-8
1234          * mode.
1235          *
1236          * @param $text Mixed: reference to a text
1237          * @return String
1238          */
1239         public static function compressRevisionText( &$text ) {
1240                 global $wgCompressRevisions;
1241                 $flags = array();
1242
1243                 # Revisions not marked this way will be converted
1244                 # on load if $wgLegacyCharset is set in the future.
1245                 $flags[] = 'utf-8';
1246
1247                 if( $wgCompressRevisions ) {
1248                         if( function_exists( 'gzdeflate' ) ) {
1249                                 $text = gzdeflate( $text );
1250                                 $flags[] = 'gzip';
1251                         } else {
1252                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1253                         }
1254                 }
1255                 return implode( ',', $flags );
1256         }
1257
1258         /**
1259          * Insert a new revision into the database, returning the new revision ID
1260          * number on success and dies horribly on failure.
1261          *
1262          * @param $dbw DatabaseBase: (master connection)
1263          * @throws MWException
1264          * @return Integer
1265          */
1266         public function insertOn( $dbw ) {
1267                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1268
1269                 wfProfileIn( __METHOD__ );
1270
1271                 $this->checkContentModel();
1272
1273                 $data = $this->mText;
1274                 $flags = self::compressRevisionText( $data );
1275
1276                 # Write to external storage if required
1277                 if( $wgDefaultExternalStore ) {
1278                         // Store and get the URL
1279                         $data = ExternalStore::insertToDefault( $data );
1280                         if( !$data ) {
1281                                 wfProfileOut( __METHOD__ );
1282                                 throw new MWException( "Unable to store text to external storage" );
1283                         }
1284                         if( $flags ) {
1285                                 $flags .= ',';
1286                         }
1287                         $flags .= 'external';
1288                 }
1289
1290                 # Record the text (or external storage URL) to the text table
1291                 if( !isset( $this->mTextId ) ) {
1292                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1293                         $dbw->insert( 'text',
1294                                 array(
1295                                         'old_id'    => $old_id,
1296                                         'old_text'  => $data,
1297                                         'old_flags' => $flags,
1298                                 ), __METHOD__
1299                         );
1300                         $this->mTextId = $dbw->insertId();
1301                 }
1302
1303                 if ( $this->mComment === null ) $this->mComment = "";
1304
1305                 # Record the edit in revisions
1306                 $rev_id = isset( $this->mId )
1307                         ? $this->mId
1308                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1309                 $row = array(
1310                         'rev_id'         => $rev_id,
1311                         'rev_page'       => $this->mPage,
1312                         'rev_text_id'    => $this->mTextId,
1313                         'rev_comment'    => $this->mComment,
1314                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1315                         'rev_user'       => $this->mUser,
1316                         'rev_user_text'  => $this->mUserText,
1317                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1318                         'rev_deleted'    => $this->mDeleted,
1319                         'rev_len'        => $this->mSize,
1320                         'rev_parent_id'  => is_null( $this->mParentId )
1321                                 ? $this->getPreviousRevisionId( $dbw )
1322                                 : $this->mParentId,
1323                         'rev_sha1'       => is_null( $this->mSha1 )
1324                                 ? Revision::base36Sha1( $this->mText )
1325                                 : $this->mSha1,
1326                 );
1327
1328                 if ( $wgContentHandlerUseDB ) {
1329                         //NOTE: Store null for the default model and format, to save space.
1330                         //XXX: Makes the DB sensitive to changed defaults. Make this behavior optional? Only in miser mode?
1331
1332                         $model = $this->getContentModel();
1333                         $format = $this->getContentFormat();
1334
1335                         $title = $this->getTitle();
1336
1337                         if ( $title === null ) {
1338                                 wfProfileOut( __METHOD__ );
1339                                 throw new MWException( "Insufficient information to determine the title of the revision's page!" );
1340                         }
1341
1342                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1343                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1344
1345                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1346                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1347                 }
1348
1349                 $dbw->insert( 'revision', $row, __METHOD__ );
1350
1351                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1352
1353                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1354
1355                 wfProfileOut( __METHOD__ );
1356                 return $this->mId;
1357         }
1358
1359         protected function checkContentModel() {
1360                 global $wgContentHandlerUseDB;
1361
1362                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1363
1364                 $model = $this->getContentModel();
1365                 $format = $this->getContentFormat();
1366                 $handler = $this->getContentHandler();
1367
1368                 if ( !$handler->isSupportedFormat( $format ) ) {
1369                         $t = $title->getPrefixedDBkey();
1370
1371                         throw new MWException( "Can't use format $format with content model $model on $t" );
1372                 }
1373
1374                 if ( !$wgContentHandlerUseDB && $title ) {
1375                         // if $wgContentHandlerUseDB is not set, all revisions must use the default content model and format.
1376
1377                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1378                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1379                         $defaultFormat = $defaultHandler->getDefaultFormat();
1380
1381                         if ( $this->getContentModel() != $defaultModel ) {
1382                                 $t = $title->getPrefixedDBkey();
1383
1384                                 throw new MWException( "Can't save non-default content model with \$wgContentHandlerUseDB disabled: "
1385                                                                                 . "model is $model , default for $t is $defaultModel" );
1386                         }
1387
1388                         if ( $this->getContentFormat() != $defaultFormat ) {
1389                                 $t = $title->getPrefixedDBkey();
1390
1391                                 throw new MWException( "Can't use non-default content format with \$wgContentHandlerUseDB disabled: "
1392                                                                                 . "format is $format, default for $t is $defaultFormat" );
1393                         }
1394                 }
1395
1396                 $content = $this->getContent( Revision::RAW );
1397
1398                 if ( !$content || !$content->isValid() ) {
1399                         $t = $title->getPrefixedDBkey();
1400
1401                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1402                 }
1403         }
1404
1405         /**
1406          * Get the base 36 SHA-1 value for a string of text
1407          * @param $text String
1408          * @return String
1409          */
1410         public static function base36Sha1( $text ) {
1411                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1412         }
1413
1414         /**
1415          * Lazy-load the revision's text.
1416          * Currently hardcoded to the 'text' table storage engine.
1417          *
1418          * @return String|bool the revision's text, or false on failure
1419          */
1420         protected function loadText() {
1421                 wfProfileIn( __METHOD__ );
1422
1423                 // Caching may be beneficial for massive use of external storage
1424                 global $wgRevisionCacheExpiry, $wgMemc;
1425                 $textId = $this->getTextId();
1426                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1427                 if( $wgRevisionCacheExpiry ) {
1428                         $text = $wgMemc->get( $key );
1429                         if( is_string( $text ) ) {
1430                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1431                                 wfProfileOut( __METHOD__ );
1432                                 return $text;
1433                         }
1434                 }
1435
1436                 // If we kept data for lazy extraction, use it now...
1437                 if ( isset( $this->mTextRow ) ) {
1438                         $row = $this->mTextRow;
1439                         $this->mTextRow = null;
1440                 } else {
1441                         $row = null;
1442                 }
1443
1444                 if( !$row ) {
1445                         // Text data is immutable; check slaves first.
1446                         $dbr = wfGetDB( DB_SLAVE );
1447                         $row = $dbr->selectRow( 'text',
1448                                 array( 'old_text', 'old_flags' ),
1449                                 array( 'old_id' => $this->getTextId() ),
1450                                 __METHOD__ );
1451                 }
1452
1453                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1454                         // Possible slave lag!
1455                         $dbw = wfGetDB( DB_MASTER );
1456                         $row = $dbw->selectRow( 'text',
1457                                 array( 'old_text', 'old_flags' ),
1458                                 array( 'old_id' => $this->getTextId() ),
1459                                 __METHOD__ );
1460                 }
1461
1462                 $text = self::getRevisionText( $row );
1463
1464                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1465                 if( $wgRevisionCacheExpiry && $text !== false ) {
1466                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1467                 }
1468
1469                 wfProfileOut( __METHOD__ );
1470
1471                 return $text;
1472         }
1473
1474         /**
1475          * Create a new null-revision for insertion into a page's
1476          * history. This will not re-save the text, but simply refer
1477          * to the text from the previous version.
1478          *
1479          * Such revisions can for instance identify page rename
1480          * operations and other such meta-modifications.
1481          *
1482          * @param $dbw DatabaseBase
1483          * @param $pageId Integer: ID number of the page to read from
1484          * @param string $summary revision's summary
1485          * @param $minor Boolean: whether the revision should be considered as minor
1486          * @return Revision|null on error
1487          */
1488         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1489                 global $wgContentHandlerUseDB;
1490
1491                 wfProfileIn( __METHOD__ );
1492
1493                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1494                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1495
1496                 if ( $wgContentHandlerUseDB ) {
1497                         $fields[] = 'rev_content_model';
1498                         $fields[] = 'rev_content_format';
1499                 }
1500
1501                 $current = $dbw->selectRow(
1502                         array( 'page', 'revision' ),
1503                         $fields,
1504                         array(
1505                                 'page_id' => $pageId,
1506                                 'page_latest=rev_id',
1507                                 ),
1508                         __METHOD__ );
1509
1510                 if( $current ) {
1511                         $row = array(
1512                                 'page'       => $pageId,
1513                                 'comment'    => $summary,
1514                                 'minor_edit' => $minor,
1515                                 'text_id'    => $current->rev_text_id,
1516                                 'parent_id'  => $current->page_latest,
1517                                 'len'        => $current->rev_len,
1518                                 'sha1'       => $current->rev_sha1
1519                         );
1520
1521                         if ( $wgContentHandlerUseDB ) {
1522                                 $row['content_model'] = $current->rev_content_model;
1523                                 $row['content_format'] = $current->rev_content_format;
1524                         }
1525
1526                         $revision = new Revision( $row );
1527                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1528                 } else {
1529                         $revision = null;
1530                 }
1531
1532                 wfProfileOut( __METHOD__ );
1533                 return $revision;
1534         }
1535
1536         /**
1537          * Determine if the current user is allowed to view a particular
1538          * field of this revision, if it's marked as deleted.
1539          *
1540          * @param $field Integer:one of self::DELETED_TEXT,
1541          *                              self::DELETED_COMMENT,
1542          *                              self::DELETED_USER
1543          * @param $user User object to check, or null to use $wgUser
1544          * @return Boolean
1545          */
1546         public function userCan( $field, User $user = null ) {
1547                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1548         }
1549
1550         /**
1551          * Determine if the current user is allowed to view a particular
1552          * field of this revision, if it's marked as deleted. This is used
1553          * by various classes to avoid duplication.
1554          *
1555          * @param $bitfield Integer: current field
1556          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1557          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1558          *                               self::DELETED_USER = File::DELETED_USER
1559          * @param $user User object to check, or null to use $wgUser
1560          * @return Boolean
1561          */
1562         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1563                 if( $bitfield & $field ) { // aspect is deleted
1564                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1565                                 $permission = 'suppressrevision';
1566                         } elseif ( $field & self::DELETED_TEXT ) {
1567                                 $permission = 'deletedtext';
1568                         } else {
1569                                 $permission = 'deletedhistory';
1570                         }
1571                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1572                         if ( $user === null ) {
1573                                 global $wgUser;
1574                                 $user = $wgUser;
1575                         }
1576                         return $user->isAllowed( $permission );
1577                 } else {
1578                         return true;
1579                 }
1580         }
1581
1582         /**
1583          * Get rev_timestamp from rev_id, without loading the rest of the row
1584          *
1585          * @param $title Title
1586          * @param $id Integer
1587          * @return String
1588          */
1589         static function getTimestampFromId( $title, $id ) {
1590                 $dbr = wfGetDB( DB_SLAVE );
1591                 // Casting fix for databases that can't take '' for rev_id
1592                 if ( $id == '' ) {
1593                         $id = 0;
1594                 }
1595                 $conds = array( 'rev_id' => $id );
1596                 $conds['rev_page'] = $title->getArticleID();
1597                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1598                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1599                         # Not in slave, try master
1600                         $dbw = wfGetDB( DB_MASTER );
1601                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1602                 }
1603                 return wfTimestamp( TS_MW, $timestamp );
1604         }
1605
1606         /**
1607          * Get count of revisions per page...not very efficient
1608          *
1609          * @param $db DatabaseBase
1610          * @param $id Integer: page id
1611          * @return Integer
1612          */
1613         static function countByPageId( $db, $id ) {
1614                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1615                         array( 'rev_page' => $id ), __METHOD__ );
1616                 if( $row ) {
1617                         return $row->revCount;
1618                 }
1619                 return 0;
1620         }
1621
1622         /**
1623          * Get count of revisions per page...not very efficient
1624          *
1625          * @param $db DatabaseBase
1626          * @param $title Title
1627          * @return Integer
1628          */
1629         static function countByTitle( $db, $title ) {
1630                 $id = $title->getArticleID();
1631                 if( $id ) {
1632                         return self::countByPageId( $db, $id );
1633                 }
1634                 return 0;
1635         }
1636
1637         /**
1638          * Check if no edits were made by other users since
1639          * the time a user started editing the page. Limit to
1640          * 50 revisions for the sake of performance.
1641          *
1642          * @since 1.20
1643          *
1644          * @param DatabaseBase|int $db the Database to perform the check on. May be given as a Database object or
1645          *        a database identifier usable with wfGetDB.
1646          * @param int $pageId the ID of the page in question
1647          * @param int $userId the ID of the user in question
1648          * @param string $since look at edits since this time
1649          *
1650          * @return bool True if the given user was the only one to edit since the given timestamp
1651          */
1652         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1653                 if ( !$userId ) return false;
1654
1655                 if ( is_int( $db ) ) {
1656                         $db = wfGetDB( $db );
1657                 }
1658
1659                 $res = $db->select( 'revision',
1660                         'rev_user',
1661                         array(
1662                                 'rev_page' => $pageId,
1663                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1664                         ),
1665                         __METHOD__,
1666                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1667                 foreach ( $res as $row ) {
1668                         if ( $row->rev_user != $userId ) {
1669                                 return false;
1670                         }
1671                 }
1672                 return true;
1673         }
1674 }