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         protected $mPage;
  29         protected $mUserText;
  30         protected $mOrigUserText;
  31         protected $mUser;
  32         protected $mMinorEdit;
  33         protected $mTimestamp;
  34         protected $mDeleted;
  35         protected $mSize;
  36         protected $mSha1;
  37         protected $mParentId;
  38         protected $mComment;
  39         protected $mText;
  40         protected $mTextRow;
  41         protected $mTitle;
  42         protected $mCurrent;
  43         protected $mContentModel;
  44         protected $mContentFormat;
  45         protected $mContent;
  46         protected $mContentHandler;
  47
  48         const DELETED_TEXT = 1;
  49         const DELETED_COMMENT = 2;
  50         const DELETED_USER = 4;
  51         const DELETED_RESTRICTED = 8;
  52         // Convenience field
  53         const SUPPRESSED_USER = 12;
  54         // Audience options for accessors
  55         const FOR_PUBLIC = 1;
  56         const FOR_THIS_USER = 2;
  57         const RAW = 3;
  58
  59         /**
  60          * Load a page revision from a given revision ID number.
  61          * Returns null if no such revision can be found.
  62          *
  63          * $flags include:
  64          *      IDBAccessObject::LATEST_READ  : Select the data from the master
  65          *      IDBAccessObject::LOCKING_READ : Select & lock the data from the master
  66          *      IDBAccessObject::AVOID_MASTER : Avoid master queries; data may be stale
  67          *
  68          * @param $id Integer
  69          * @param $flags Integer (optional)
  70          * @return Revision or null
  71          */
  72         public static function newFromId( $id, $flags = 0 ) {
  73                 return self::newFromConds( array( 'rev_id' => intval( $id ) ), $flags );
  74         }
  75
  76         /**
  77          * Load either the current, or a specified, revision
  78          * that's attached to a given title. If not attached
  79          * to that title, will return null.
  80          *
  81          * $flags include:
  82          *      IDBAccessObject::LATEST_READ  : Select the data from the master
  83          *      IDBAccessObject::LOCKING_READ : Select & lock the data from the master
  84          *      IDBAccessObject::AVOID_MASTER : Avoid master queries; data may be stale
  85          *
  86          * @param $title Title
  87          * @param $id Integer (optional)
  88          * @param $flags Integer Bitfield (optional)
  89          * @return Revision or null
  90          */
  91         public static function newFromTitle( $title, $id = 0, $flags = 0 ) {
  92                 $conds = array(
  93                         'page_namespace' => $title->getNamespace(),
  94                         'page_title'     => $title->getDBkey()
  95                 );
  96                 if ( $id ) {
  97                         // Use the specified ID
  98                         $conds['rev_id'] = $id;
  99                 } elseif ( !( $flags & self::AVOID_MASTER ) && wfGetLB()->getServerCount() > 1 ) {
 100                         // Get the latest revision ID from the master
 101                         $dbw = wfGetDB( DB_MASTER );
 102                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
 103                         if ( $latest === false ) {
 104                                 return null; // page does not exist
 105                         }
 106                         $conds['rev_id'] = $latest;
 107                 } else {
 108                         // Use a join to get the latest revision
 109                         $conds[] = 'rev_id=page_latest';
 110                 }
 111                 return self::newFromConds( $conds, $flags );
 112         }
 113
 114         /**
 115          * Load either the current, or a specified, revision
 116          * that's attached to a given page ID.
 117          * Returns null if no such revision can be found.
 118          *
 119          * $flags include:
 120          *      IDBAccessObject::LATEST_READ  : Select the data from the master
 121          *      IDBAccessObject::LOCKING_READ : Select & lock the data from the master
 122          *      IDBAccessObject::AVOID_MASTER : Avoid master queries; data may be stale
 123          *
 124          * @param $revId Integer
 125          * @param $pageId Integer (optional)
 126          * @param $flags Integer Bitfield (optional)
 127          * @return Revision or null
 128          */
 129         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 130                 $conds = array( 'page_id' => $pageId );
 131                 if ( $revId ) {
 132                         $conds['rev_id'] = $revId;
 133                 } elseif ( !( $flags & self::AVOID_MASTER ) && wfGetLB()->getServerCount() > 1 ) {
 134                         // Get the latest revision ID from the master
 135                         $dbw = wfGetDB( DB_MASTER );
 136                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
 137                         if ( $latest === false ) {
 138                                 return null; // page does not exist
 139                         }
 140                         $conds['rev_id'] = $latest;
 141                 } else {
 142                         $conds[] = 'rev_id = page_latest';
 143                 }
 144                 return self::newFromConds( $conds, $flags );
 145         }
 146
 147         /**
 148          * Make a fake revision object from an archive table row. This is queried
 149          * for permissions or even inserted (as in Special:Undelete)
 150          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 151          *
 152          * @param $row
 153          * @param $overrides array
 154          *
 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( $row->ar_text ) && !$row->ar_text_id ) {
 182                         // Pre-1.5 ar_text row
 183                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 184                         if ( $attribs['text'] === false ) {
 185                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 186                         }
 187                 }
 188                 return new self( $attribs );
 189         }
 190
 191         /**
 192          * @since 1.19
 193          *
 194          * @param $row
 195          * @return Revision
 196          */
 197         public static function newFromRow( $row ) {
 198                 return new self( $row );
 199         }
 200
 201         /**
 202          * Load a page revision from a given revision ID number.
 203          * Returns null if no such revision can be found.
 204          *
 205          * @param $db DatabaseBase
 206          * @param $id Integer
 207          * @return Revision or null
 208          */
 209         public static function loadFromId( $db, $id ) {
 210                 return self::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 211         }
 212
 213         /**
 214          * Load either the current, or a specified, revision
 215          * that's attached to a given page. If not attached
 216          * to that page, will return null.
 217          *
 218          * @param $db DatabaseBase
 219          * @param $pageid Integer
 220          * @param $id Integer
 221          * @return Revision or null
 222          */
 223         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 224                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 225                 if( $id ) {
 226                         $conds['rev_id'] = intval( $id );
 227                 } else {
 228                         $conds[] = 'rev_id=page_latest';
 229                 }
 230                 return self::loadFromConds( $db, $conds );
 231         }
 232
 233         /**
 234          * Load either the current, or a specified, revision
 235          * that's attached to a given page. If not attached
 236          * to that page, will return null.
 237          *
 238          * @param $db DatabaseBase
 239          * @param $title Title
 240          * @param $id Integer
 241          * @return Revision or null
 242          */
 243         public static function loadFromTitle( $db, $title, $id = 0 ) {
 244                 if( $id ) {
 245                         $matchId = intval( $id );
 246                 } else {
 247                         $matchId = 'page_latest';
 248                 }
 249                 return self::loadFromConds( $db,
 250                         array( "rev_id=$matchId",
 251                                    'page_namespace' => $title->getNamespace(),
 252                                    'page_title'     => $title->getDBkey() )
 253                 );
 254         }
 255
 256         /**
 257          * Load the revision for the given title with the given timestamp.
 258          * WARNING: Timestamps may in some circumstances not be unique,
 259          * so this isn't the best key to use.
 260          *
 261          * @param $db DatabaseBase
 262          * @param $title Title
 263          * @param $timestamp String
 264          * @return Revision or null
 265          */
 266         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 267                 return self::loadFromConds( $db,
 268                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 269                                    'page_namespace' => $title->getNamespace(),
 270                                    'page_title'     => $title->getDBkey() )
 271                 );
 272         }
 273
 274         /**
 275          * Given a set of conditions, fetch a revision.
 276          *
 277          * @param $conditions Array
 278          * @param $flags integer (optional)
 279          * @return Revision or null
 280          */
 281         private static function newFromConds( $conditions, $flags = 0 ) {
 282                 $db = wfGetDB( ( $flags & self::LATEST_READ ) ? DB_MASTER : DB_SLAVE );
 283                 $rev = self::loadFromConds( $db, $conditions, $flags );
 284                 if ( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 285                         if ( !( $flags & self::LATEST_READ ) && !( $flags & self::AVOID_MASTER ) ) {
 286                                 $dbw = wfGetDB( DB_MASTER );
 287                                 $rev = self::loadFromConds( $dbw, $conditions, $flags );
 288                         }
 289                 }
 290                 return $rev;
 291         }
 292
 293         /**
 294          * Given a set of conditions, fetch a revision from
 295          * the given database connection.
 296          *
 297          * @param $db DatabaseBase
 298          * @param $conditions Array
 299          * @param $flags integer (optional)
 300          * @return Revision or null
 301          */
 302         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 303                 $res = self::fetchFromConds( $db, $conditions, $flags );
 304                 if( $res ) {
 305                         $row = $res->fetchObject();
 306                         if( $row ) {
 307                                 $ret = new Revision( $row );
 308                                 return $ret;
 309                         }
 310                 }
 311                 $ret = null;
 312                 return $ret;
 313         }
 314
 315         /**
 316          * Return a wrapper for a series of database rows to
 317          * fetch all of a given page's revisions in turn.
 318          * Each row can be fed to the constructor to get objects.
 319          *
 320          * @param $title Title
 321          * @return ResultWrapper
 322          */
 323         public static function fetchRevision( $title ) {
 324                 return self::fetchFromConds(
 325                         wfGetDB( DB_SLAVE ),
 326                         array( 'rev_id=page_latest',
 327                                    'page_namespace' => $title->getNamespace(),
 328                                    'page_title'     => $title->getDBkey() )
 329                 );
 330         }
 331
 332         /**
 333          * Given a set of conditions, return a ResultWrapper
 334          * which will return matching database rows with the
 335          * fields necessary to build Revision objects.
 336          *
 337          * @param $db DatabaseBase
 338          * @param $conditions Array
 339          * @param $flags integer (optional)
 340          * @return ResultWrapper
 341          */
 342         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 343                 $fields = array_merge(
 344                         self::selectFields(),
 345                         self::selectPageFields(),
 346                         self::selectUserFields()
 347                 );
 348                 $options = array( 'LIMIT' => 1 );
 349                 if ( $flags & self::FOR_UPDATE ) {
 350                         $options[] = 'FOR UPDATE';
 351                 }
 352                 return $db->select(
 353                         array( 'revision', 'page', 'user' ),
 354                         $fields,
 355                         $conditions,
 356                         __METHOD__,
 357                         $options,
 358                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 359                 );
 360         }
 361
 362         /**
 363          * Return the value of a select() JOIN conds array for the user table.
 364          * This will get user table rows for logged-in users.
 365          * @since 1.19
 366          * @return Array
 367          */
 368         public static function userJoinCond() {
 369                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 370         }
 371
 372         /**
 373          * Return the value of a select() page conds array for the paeg table.
 374          * This will assure that the revision(s) are not orphaned from live pages.
 375          * @since 1.19
 376          * @return Array
 377          */
 378         public static function pageJoinCond() {
 379                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 380         }
 381
 382         /**
 383          * Return the list of revision fields that should be selected to create
 384          * a new revision.
 385          * @return array
 386          */
 387         public static function selectFields() {
 388                 global $wgContentHandlerUseDB;
 389
 390                 $fields = array(
 391                         'rev_id',
 392                         'rev_page',
 393                         'rev_text_id',
 394                         'rev_timestamp',
 395                         'rev_comment',
 396                         'rev_user_text',
 397                         'rev_user',
 398                         'rev_minor_edit',
 399                         'rev_deleted',
 400                         'rev_len',
 401                         'rev_parent_id',
 402                         'rev_sha1',
 403                 );
 404
 405                 if ( $wgContentHandlerUseDB ) {
 406                         $fields[] = 'rev_content_format';
 407                         $fields[] = 'rev_content_model';
 408                 }
 409
 410                 return $fields;
 411         }
 412
 413         /**
 414          * Return the list of text fields that should be selected to read the
 415          * revision text
 416          * @return array
 417          */
 418         public static function selectTextFields() {
 419                 return array(
 420                         'old_text',
 421                         'old_flags'
 422                 );
 423         }
 424
 425         /**
 426          * Return the list of page fields that should be selected from page table
 427          * @return array
 428          */
 429         public static function selectPageFields() {
 430                 return array(
 431                         'page_namespace',
 432                         'page_title',
 433                         'page_id',
 434                         'page_latest',
 435                         'page_is_redirect',
 436                         'page_len',
 437                 );
 438         }
 439
 440         /**
 441          * Return the list of user fields that should be selected from user table
 442          * @return array
 443          */
 444         public static function selectUserFields() {
 445                 return array( 'user_name' );
 446         }
 447
 448         /**
 449          * Do a batched query to get the parent revision lengths
 450          * @param $db DatabaseBase
 451          * @param $revIds Array
 452          * @return array
 453          */
 454         public static function getParentLengths( $db, array $revIds ) {
 455                 $revLens = array();
 456                 if ( !$revIds ) {
 457                         return $revLens; // empty
 458                 }
 459                 wfProfileIn( __METHOD__ );
 460                 $res = $db->select( 'revision',
 461                         array( 'rev_id', 'rev_len' ),
 462                         array( 'rev_id' => $revIds ),
 463                         __METHOD__ );
 464                 foreach ( $res as $row ) {
 465                         $revLens[$row->rev_id] = $row->rev_len;
 466                 }
 467                 wfProfileOut( __METHOD__ );
 468                 return $revLens;
 469         }
 470
 471         /**
 472          * Constructor
 473          *
 474          * @param $row Mixed: either a database row or an array
 475          * @access private
 476          */
 477         function __construct( $row ) {
 478                 if( is_object( $row ) ) {
 479                         $this->mId        = intval( $row->rev_id );
 480                         $this->mPage      = intval( $row->rev_page );
 481                         $this->mTextId    = intval( $row->rev_text_id );
 482                         $this->mComment   =         $row->rev_comment;
 483                         $this->mUser      = intval( $row->rev_user );
 484                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 485                         $this->mTimestamp =         $row->rev_timestamp;
 486                         $this->mDeleted   = intval( $row->rev_deleted );
 487
 488                         if( !isset( $row->rev_parent_id ) ) {
 489                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 490                         } else {
 491                                 $this->mParentId  = intval( $row->rev_parent_id );
 492                         }
 493
 494                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 495                                 $this->mSize = null;
 496                         } else {
 497                                 $this->mSize = intval( $row->rev_len );
 498                         }
 499
 500                         if ( !isset( $row->rev_sha1 ) ) {
 501                                 $this->mSha1 = null;
 502                         } else {
 503                                 $this->mSha1 = $row->rev_sha1;
 504                         }
 505
 506                         if( isset( $row->page_latest ) ) {
 507                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 508                                 $this->mTitle = Title::newFromRow( $row );
 509                         } else {
 510                                 $this->mCurrent = false;
 511                                 $this->mTitle = null;
 512                         }
 513
 514                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 515                                 $this->mContentModel = null; # determine on demand if needed
 516                         } else {
 517                                 $this->mContentModel = strval( $row->rev_content_model );
 518                         }
 519
 520                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 521                                 $this->mContentFormat = null; # determine on demand if needed
 522                         } else {
 523                                 $this->mContentFormat = strval( $row->rev_content_format );
 524                         }
 525
 526                         // Lazy extraction...
 527                         $this->mText      = null;
 528                         if( isset( $row->old_text ) ) {
 529                                 $this->mTextRow = $row;
 530                         } else {
 531                                 // 'text' table row entry will be lazy-loaded
 532                                 $this->mTextRow = null;
 533                         }
 534
 535                         // Use user_name for users and rev_user_text for IPs...
 536                         $this->mUserText = null; // lazy load if left null
 537                         if ( $this->mUser == 0 ) {
 538                                 $this->mUserText = $row->rev_user_text; // IP user
 539                         } elseif ( isset( $row->user_name ) ) {
 540                                 $this->mUserText = $row->user_name; // logged-in user
 541                         }
 542                         $this->mOrigUserText = $row->rev_user_text;
 543                 } elseif( is_array( $row ) ) {
 544                         // Build a new revision to be saved...
 545                         global $wgUser; // ugh
 546
 547
 548                         # if we have a content object, use it to set the model and type
 549                         if ( !empty( $row['content'] ) ) {
 550                                 if ( !empty( $row['text_id'] ) ) { //@todo: when is that set? test with external store setup! check out insertOn() [dk]
 551                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), can't serialize content object" );
 552                                 }
 553
 554                                 $row['content_model'] = $row['content']->getModel();
 555                                 # note: mContentFormat is initializes later accordingly
 556                                 # note: content is serialized later in this method!
 557                                 # also set text to null?
 558                         }
 559
 560                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 561                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 562                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 563                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 564                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 565                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 566                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 567                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 568                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 569                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 570                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 571
 572                         $this->mContentModel = isset( $row['content_model']  )  ? strval( $row['content_model'] )  : null;
 573                         $this->mContentFormat    = isset( $row['content_format']  ) ? strval( $row['content_format'] ) : null;
 574
 575                         // Enforce spacing trimming on supplied text
 576                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 577                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 578                         $this->mTextRow   = null;
 579
 580                         $this->mTitle     = isset( $row['title']      ) ? $row['title'] : null;
 581
 582                         // if we have a Content object, override mText and mContentModel
 583                         if ( !empty( $row['content'] ) ) {
 584                                 $handler = $this->getContentHandler();
 585                                 $this->mContent = $row['content'];
 586
 587                                 $this->mContentModel = $this->mContent->getModel();
 588                                 $this->mContentHandler = null;
 589
 590                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 591                         } elseif ( !is_null( $this->mText ) ) {
 592                                 $handler = $this->getContentHandler();
 593                                 $this->mContent = $handler->unserializeContent( $this->mText );
 594                         }
 595
 596                         // if we have a Title object, override mPage. Useful for testing and convenience.
 597                         if ( isset( $row['title'] ) ) {
 598                                 $this->mTitle     = $row['title'];
 599                                 $this->mPage      = $this->mTitle->getArticleID();
 600                         } else {
 601                                 $this->mTitle     = null; // Load on demand if needed
 602                         }
 603
 604                         $this->mCurrent   = false; // @todo: XXX: really? we are about to create a revision. it will usually then be the current one.
 605
 606                         // If we still have no length, see it we have the text to figure it out
 607                         if ( !$this->mSize ) {
 608                                 if ( !is_null( $this->mContent ) ) {
 609                                         $this->mSize = $this->mContent->getSize();
 610                                 } else {
 611                                         #NOTE: this should never happen if we have either text or content object!
 612                                         $this->mSize = null;
 613                                 }
 614                         }
 615
 616                         // Same for sha1
 617                         if ( $this->mSha1 === null ) {
 618                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 619                         }
 620
 621                         // force lazy init
 622                         $this->getContentModel();
 623                         $this->getContentFormat();
 624                 } else {
 625                         throw new MWException( 'Revision constructor passed invalid row format.' );
 626                 }
 627                 $this->mUnpatrolled = null;
 628         }
 629
 630         /**
 631          * Get revision ID
 632          *
 633          * @return Integer|null
 634          */
 635         public function getId() {
 636                 return $this->mId;
 637         }
 638
 639         /**
 640          * Set the revision ID
 641          *
 642          * @since 1.19
 643          * @param $id Integer
 644          */
 645         public function setId( $id ) {
 646                 $this->mId = $id;
 647         }
 648
 649         /**
 650          * Get text row ID
 651          *
 652          * @return Integer|null
 653          */
 654         public function getTextId() {
 655                 return $this->mTextId;
 656         }
 657
 658         /**
 659          * Get parent revision ID (the original previous page revision)
 660          *
 661          * @return Integer|null
 662          */
 663         public function getParentId() {
 664                 return $this->mParentId;
 665         }
 666
 667         /**
 668          * Returns the length of the text in this revision, or null if unknown.
 669          *
 670          * @return Integer|null
 671          */
 672         public function getSize() {
 673                 return $this->mSize;
 674         }
 675
 676         /**
 677          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 678          *
 679          * @return String|null
 680          */
 681         public function getSha1() {
 682                 return $this->mSha1;
 683         }
 684
 685         /**
 686          * Returns the title of the page associated with this entry or null.
 687          *
 688          * Will do a query, when title is not set and id is given.
 689          *
 690          * @return Title|null
 691          */
 692         public function getTitle() {
 693                 if( isset( $this->mTitle ) ) {
 694                         return $this->mTitle;
 695                 }
 696                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 697                         $dbr = wfGetDB( DB_SLAVE );
 698                         $row = $dbr->selectRow(
 699                                 array( 'page', 'revision' ),
 700                                 self::selectPageFields(),
 701                                 array( 'page_id=rev_page',
 702                                            'rev_id' => $this->mId ),
 703                                 __METHOD__ );
 704                         if ( $row ) {
 705                                 $this->mTitle = Title::newFromRow( $row );
 706                         }
 707                 }
 708
 709                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 710                         $this->mTitle = Title::newFromID( $this->mPage );
 711                 }
 712
 713                 return $this->mTitle;
 714         }
 715
 716         /**
 717          * Set the title of the revision
 718          *
 719          * @param $title Title
 720          */
 721         public function setTitle( $title ) {
 722                 $this->mTitle = $title;
 723         }
 724
 725         /**
 726          * Get the page ID
 727          *
 728          * @return Integer|null
 729          */
 730         public function getPage() {
 731                 return $this->mPage;
 732         }
 733
 734         /**
 735          * Fetch revision's user id if it's available to the specified audience.
 736          * If the specified audience does not have access to it, zero will be
 737          * returned.
 738          *
 739          * @param $audience Integer: one of:
 740          *      Revision::FOR_PUBLIC       to be displayed to all users
 741          *      Revision::FOR_THIS_USER    to be displayed to the given user
 742          *      Revision::RAW              get the ID regardless of permissions
 743          * @param $user User object to check for, only if FOR_THIS_USER is passed
 744          *              to the $audience parameter
 745          * @return Integer
 746          */
 747         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 748                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 749                         return 0;
 750                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 751                         return 0;
 752                 } else {
 753                         return $this->mUser;
 754                 }
 755         }
 756
 757         /**
 758          * Fetch revision's user id without regard for the current user's permissions
 759          *
 760          * @return String
 761          */
 762         public function getRawUser() {
 763                 return $this->mUser;
 764         }
 765
 766         /**
 767          * Fetch revision's username if it's available to the specified audience.
 768          * If the specified audience does not have access to the username, an
 769          * empty string will be returned.
 770          *
 771          * @param $audience Integer: one of:
 772          *      Revision::FOR_PUBLIC       to be displayed to all users
 773          *      Revision::FOR_THIS_USER    to be displayed to the given user
 774          *      Revision::RAW              get the text regardless of permissions
 775          * @param $user User object to check for, only if FOR_THIS_USER is passed
 776          *              to the $audience parameter
 777          * @return string
 778          */
 779         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 780                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 781                         return '';
 782                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 783                         return '';
 784                 } else {
 785                         return $this->getRawUserText();
 786                 }
 787         }
 788
 789         /**
 790          * Fetch revision's username without regard for view restrictions
 791          *
 792          * @return String
 793          */
 794         public function getRawUserText() {
 795                 if ( $this->mUserText === null ) {
 796                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 797                         if ( $this->mUserText === false ) {
 798                                 # This shouldn't happen, but it can if the wiki was recovered
 799                                 # via importing revs and there is no user table entry yet.
 800                                 $this->mUserText = $this->mOrigUserText;
 801                         }
 802                 }
 803                 return $this->mUserText;
 804         }
 805
 806         /**
 807          * Fetch revision comment if it's available to the specified audience.
 808          * If the specified audience does not have access to the comment, an
 809          * empty string will be returned.
 810          *
 811          * @param $audience Integer: one of:
 812          *      Revision::FOR_PUBLIC       to be displayed to all users
 813          *      Revision::FOR_THIS_USER    to be displayed to the given user
 814          *      Revision::RAW              get the text regardless of permissions
 815          * @param $user User object to check for, only if FOR_THIS_USER is passed
 816          *              to the $audience parameter
 817          * @return String
 818          */
 819         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 820                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 821                         return '';
 822                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 823                         return '';
 824                 } else {
 825                         return $this->mComment;
 826                 }
 827         }
 828
 829         /**
 830          * Fetch revision comment without regard for the current user's permissions
 831          *
 832          * @return String
 833          */
 834         public function getRawComment() {
 835                 return $this->mComment;
 836         }
 837
 838         /**
 839          * @return Boolean
 840          */
 841         public function isMinor() {
 842                 return (bool)$this->mMinorEdit;
 843         }
 844
 845         /**
 846          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 847          */
 848         public function isUnpatrolled() {
 849                 if( $this->mUnpatrolled !== null ) {
 850                         return $this->mUnpatrolled;
 851                 }
 852                 $dbr = wfGetDB( DB_SLAVE );
 853                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 854                         'rc_id',
 855                         array( // Add redundant user,timestamp condition so we can use the existing index
 856                                 'rc_user_text'  => $this->getRawUserText(),
 857                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 858                                 'rc_this_oldid' => $this->getId(),
 859                                 'rc_patrolled'  => 0
 860                         ),
 861                         __METHOD__
 862                 );
 863                 return (int)$this->mUnpatrolled;
 864         }
 865
 866         /**
 867          * @param $field int one of DELETED_* bitfield constants
 868          *
 869          * @return Boolean
 870          */
 871         public function isDeleted( $field ) {
 872                 return ( $this->mDeleted & $field ) == $field;
 873         }
 874
 875         /**
 876          * Get the deletion bitfield of the revision
 877          *
 878          * @return int
 879          */
 880         public function getVisibility() {
 881                 return (int)$this->mDeleted;
 882         }
 883
 884         /**
 885          * Fetch revision text if it's available to the specified audience.
 886          * If the specified audience does not have the ability to view this
 887          * revision, an empty string will be returned.
 888          *
 889          * @param $audience Integer: one of:
 890          *      Revision::FOR_PUBLIC       to be displayed to all users
 891          *      Revision::FOR_THIS_USER    to be displayed to the given user
 892          *      Revision::RAW              get the text regardless of permissions
 893          * @param $user User object to check for, only if FOR_THIS_USER is passed
 894          *              to the $audience parameter
 895          * @return String
 896          * @deprecated in 1.WD, use getContent() instead
 897          * @todo: replace usage in core
 898          */
 899         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 900                 wfDeprecated( __METHOD__, '1.WD' );
 901
 902                 $content = $this->getContent( $audience, $user );
 903                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 904         }
 905
 906         /**
 907          * Fetch revision content if it's available to the specified audience.
 908          * If the specified audience does not have the ability to view this
 909          * revision, null will be returned.
 910          *
 911          * @param $audience Integer: one of:
 912          *      Revision::FOR_PUBLIC       to be displayed to all users
 913          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 914          *      Revision::RAW              get the text regardless of permissions
 915          * @param $user User object to check for, only if FOR_THIS_USER is passed
 916          *              to the $audience parameter
 917          * @return Content
 918          *
 919          * @since 1.WD
 920          */
 921         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 922                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 923                         return null;
 924                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 925                         return null;
 926                 } else {
 927                         return $this->getContentInternal();
 928                 }
 929         }
 930
 931         /**
 932          * Alias for getText(Revision::FOR_THIS_USER)
 933          *
 934          * @deprecated since 1.17
 935          * @return String
 936          */
 937         public function revText() {
 938                 wfDeprecated( __METHOD__, '1.17' );
 939                 return $this->getText( self::FOR_THIS_USER );
 940         }
 941
 942         /**
 943          * Fetch revision text without regard for view restrictions
 944          *
 945          * @return String
 946          *
 947          * @deprecated since 1.WD. Instead, use Revision::getContent( Revision::RAW ) or Revision::getSerializedData() as appropriate.
 948          */
 949         public function getRawText() {
 950                 wfDeprecated( __METHOD__, "1.WD" );
 951
 952                 return $this->getText( self::RAW );
 953         }
 954
 955         /**
 956          * Fetch original serialized data without regard for view restrictions
 957          *
 958          * @return String
 959          *
 960          * @since 1.WD
 961          */
 962         public function getSerializedData() {
 963                 return $this->mText;
 964         }
 965
 966         protected function getContentInternal() {
 967                 if( is_null( $this->mContent ) ) {
 968                         // Revision is immutable. Load on demand:
 969
 970                         $handler = $this->getContentHandler();
 971                         $format = $this->getContentFormat();
 972                         $title = $this->getTitle();
 973
 974                         if( is_null( $this->mText ) ) {
 975                                 // Load text on demand:
 976                                 $this->mText = $this->loadText();
 977                         }
 978
 979                         $this->mContent = is_null( $this->mText ) ? null : $handler->unserializeContent( $this->mText, $format );
 980                 }
 981
 982                 return $this->mContent;
 983         }
 984
 985         /**
 986          * Returns the content model for this revision.
 987          *
 988          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
 989          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
 990          * is used as a last resort.
 991          *
 992          * @return String the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
 993          **/
 994         public function getContentModel() {
 995                 if ( !$this->mContentModel ) {
 996                         $title = $this->getTitle();
 997                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
 998
 999                         assert( !empty( $this->mContentModel ) );
1000                 }
1001
1002                 return $this->mContentModel;
1003         }
1004
1005         /**
1006          * Returns the content format for this revision.
1007          *
1008          * If no content format was stored in the database, the default format for this
1009          * revision's content model is returned.
1010          *
1011          * @return String the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
1012          **/
1013         public function getContentFormat() {
1014                 if ( !$this->mContentFormat ) {
1015                         $handler = $this->getContentHandler();
1016                         $this->mContentFormat = $handler->getDefaultFormat();
1017
1018                         assert( !empty( $this->mContentFormat ) );
1019                 }
1020
1021                 return $this->mContentFormat;
1022         }
1023
1024         /**
1025          * Returns the content handler appropriate for this revision's content model.
1026          *
1027          * @return ContentHandler
1028          */
1029         public function getContentHandler() {
1030                 if ( !$this->mContentHandler ) {
1031                         $model = $this->getContentModel();
1032                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1033
1034                         $format = $this->getContentFormat();
1035
1036                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1037                                 throw new MWException( "Oops, the content format $format is not supported for this content model, $model" );
1038                         }
1039                 }
1040
1041                 return $this->mContentHandler;
1042         }
1043
1044         /**
1045          * @return String
1046          */
1047         public function getTimestamp() {
1048                 return wfTimestamp( TS_MW, $this->mTimestamp );
1049         }
1050
1051         /**
1052          * @return Boolean
1053          */
1054         public function isCurrent() {
1055                 return $this->mCurrent;
1056         }
1057
1058         /**
1059          * Get previous revision for this title
1060          *
1061          * @return Revision or null
1062          */
1063         public function getPrevious() {
1064                 if( $this->getTitle() ) {
1065                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1066                         if( $prev ) {
1067                                 return self::newFromTitle( $this->getTitle(), $prev );
1068                         }
1069                 }
1070                 return null;
1071         }
1072
1073         /**
1074          * Get next revision for this title
1075          *
1076          * @return Revision or null
1077          */
1078         public function getNext() {
1079                 if( $this->getTitle() ) {
1080                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1081                         if ( $next ) {
1082                                 return self::newFromTitle( $this->getTitle(), $next );
1083                         }
1084                 }
1085                 return null;
1086         }
1087
1088         /**
1089          * Get previous revision Id for this page_id
1090          * This is used to populate rev_parent_id on save
1091          *
1092          * @param $db DatabaseBase
1093          * @return Integer
1094          */
1095         private function getPreviousRevisionId( $db ) {
1096                 if( is_null( $this->mPage ) ) {
1097                         return 0;
1098                 }
1099                 # Use page_latest if ID is not given
1100                 if( !$this->mId ) {
1101                         $prevId = $db->selectField( 'page', 'page_latest',
1102                                 array( 'page_id' => $this->mPage ),
1103                                 __METHOD__ );
1104                 } else {
1105                         $prevId = $db->selectField( 'revision', 'rev_id',
1106                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1107                                 __METHOD__,
1108                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1109                 }
1110                 return intval( $prevId );
1111         }
1112
1113         /**
1114           * Get revision text associated with an old or archive row
1115           * $row is usually an object from wfFetchRow(), both the flags and the text
1116           * field must be included
1117           *
1118           * @param $row Object: the text data
1119           * @param $prefix String: table prefix (default 'old_')
1120           * @return String: text the text requested or false on failure
1121           */
1122         public static function getRevisionText( $row, $prefix = 'old_' ) {
1123                 wfProfileIn( __METHOD__ );
1124
1125                 # Get data
1126                 $textField = $prefix . 'text';
1127                 $flagsField = $prefix . 'flags';
1128
1129                 if( isset( $row->$flagsField ) ) {
1130                         $flags = explode( ',', $row->$flagsField );
1131                 } else {
1132                         $flags = array();
1133                 }
1134
1135                 if( isset( $row->$textField ) ) {
1136                         $text = $row->$textField;
1137                 } else {
1138                         wfProfileOut( __METHOD__ );
1139                         return false;
1140                 }
1141
1142                 # Use external methods for external objects, text in table is URL-only then
1143                 if ( in_array( 'external', $flags ) ) {
1144                         $url = $text;
1145                         $parts = explode( '://', $url, 2 );
1146                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1147                                 wfProfileOut( __METHOD__ );
1148                                 return false;
1149                         }
1150                         $text = ExternalStore::fetchFromURL( $url );
1151                 }
1152
1153                 // If the text was fetched without an error, convert it
1154                 if ( $text !== false ) {
1155                         if( in_array( 'gzip', $flags ) ) {
1156                                 # Deal with optional compression of archived pages.
1157                                 # This can be done periodically via maintenance/compressOld.php, and
1158                                 # as pages are saved if $wgCompressRevisions is set.
1159                                 $text = gzinflate( $text );
1160                         }
1161
1162                         if( in_array( 'object', $flags ) ) {
1163                                 # Generic compressed storage
1164                                 $obj = unserialize( $text );
1165                                 if ( !is_object( $obj ) ) {
1166                                         // Invalid object
1167                                         wfProfileOut( __METHOD__ );
1168                                         return false;
1169                                 }
1170                                 $text = $obj->getText();
1171                         }
1172
1173                         global $wgLegacyEncoding;
1174                         if( $text !== false && $wgLegacyEncoding
1175                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1176                         {
1177                                 # Old revisions kept around in a legacy encoding?
1178                                 # Upconvert on demand.
1179                                 # ("utf8" checked for compatibility with some broken
1180                                 #  conversion scripts 2008-12-30)
1181                                 global $wgContLang;
1182                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1183                         }
1184                 }
1185                 wfProfileOut( __METHOD__ );
1186                 return $text;
1187         }
1188
1189         /**
1190          * If $wgCompressRevisions is enabled, we will compress data.
1191          * The input string is modified in place.
1192          * Return value is the flags field: contains 'gzip' if the
1193          * data is compressed, and 'utf-8' if we're saving in UTF-8
1194          * mode.
1195          *
1196          * @param $text Mixed: reference to a text
1197          * @return String
1198          */
1199         public static function compressRevisionText( &$text ) {
1200                 global $wgCompressRevisions;
1201                 $flags = array();
1202
1203                 # Revisions not marked this way will be converted
1204                 # on load if $wgLegacyCharset is set in the future.
1205                 $flags[] = 'utf-8';
1206
1207                 if( $wgCompressRevisions ) {
1208                         if( function_exists( 'gzdeflate' ) ) {
1209                                 $text = gzdeflate( $text );
1210                                 $flags[] = 'gzip';
1211                         } else {
1212                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1213                         }
1214                 }
1215                 return implode( ',', $flags );
1216         }
1217
1218         /**
1219          * Insert a new revision into the database, returning the new revision ID
1220          * number on success and dies horribly on failure.
1221          *
1222          * @param $dbw DatabaseBase: (master connection)
1223          * @return Integer
1224          */
1225         public function insertOn( $dbw ) {
1226                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1227
1228                 wfProfileIn( __METHOD__ );
1229
1230                 $this->checkContentModel();
1231
1232                 $data = $this->mText;
1233                 $flags = self::compressRevisionText( $data );
1234
1235                 # Write to external storage if required
1236                 if( $wgDefaultExternalStore ) {
1237                         // Store and get the URL
1238                         $data = ExternalStore::insertToDefault( $data );
1239                         if( !$data ) {
1240                                 throw new MWException( "Unable to store text to external storage" );
1241                         }
1242                         if( $flags ) {
1243                                 $flags .= ',';
1244                         }
1245                         $flags .= 'external';
1246                 }
1247
1248                 # Record the text (or external storage URL) to the text table
1249                 if( !isset( $this->mTextId ) ) {
1250                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1251                         $dbw->insert( 'text',
1252                                 array(
1253                                         'old_id'    => $old_id,
1254                                         'old_text'  => $data,
1255                                         'old_flags' => $flags,
1256                                 ), __METHOD__
1257                         );
1258                         $this->mTextId = $dbw->insertId();
1259                 }
1260
1261                 if ( $this->mComment === null ) $this->mComment = "";
1262
1263                 # Record the edit in revisions
1264                 $rev_id = isset( $this->mId )
1265                         ? $this->mId
1266                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1267                 $row = array(
1268                         'rev_id'         => $rev_id,
1269                         'rev_page'       => $this->mPage,
1270                         'rev_text_id'    => $this->mTextId,
1271                         'rev_comment'    => $this->mComment,
1272                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1273                         'rev_user'       => $this->mUser,
1274                         'rev_user_text'  => $this->mUserText,
1275                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1276                         'rev_deleted'    => $this->mDeleted,
1277                         'rev_len'        => $this->mSize,
1278                         'rev_parent_id'  => is_null( $this->mParentId )
1279                                 ? $this->getPreviousRevisionId( $dbw )
1280                                 : $this->mParentId,
1281                         'rev_sha1'       => is_null( $this->mSha1 )
1282                                 ? Revision::base36Sha1( $this->mText )
1283                                 : $this->mSha1,
1284                 );
1285
1286                 if ( $wgContentHandlerUseDB ) {
1287                         //NOTE: Store null for the default model and format, to save space.
1288                         //XXX: Makes the DB sensitive to changed defaults. Make this behaviour optional? Only in miser mode?
1289
1290                         $model = $this->getContentModel();
1291                         $format = $this->getContentFormat();
1292
1293                         $defaultModel = ContentHandler::getDefaultModelFor( $this->getTitle() );
1294                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1295
1296                         $row[ 'rev_content_model' ] = ( $model === $defaultModel ) ? null : $model;
1297                         $row[ 'rev_content_format' ] = ( $format === $defaultFormat ) ? null : $format;
1298                 }
1299
1300                 $dbw->insert( 'revision', $row, __METHOD__ );
1301
1302                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1303
1304                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1305
1306                 wfProfileOut( __METHOD__ );
1307                 return $this->mId;
1308         }
1309
1310         protected function checkContentModel() {
1311                 global $wgContentHandlerUseDB;
1312
1313                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1314
1315                 $model = $this->getContentModel();
1316                 $format = $this->getContentFormat();
1317                 $handler = $this->getContentHandler();
1318
1319                 if ( !$handler->isSupportedFormat( $format ) ) {
1320                         $t = $title->getPrefixedDBkey();
1321
1322                         throw new MWException( "Can't use format $format with content model $model on $t" );
1323                 }
1324
1325                 if ( !$wgContentHandlerUseDB && $title ) {
1326                         // if $wgContentHandlerUseDB is not set, all revisions must use the default content model and format.
1327
1328                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1329                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1330                         $defaultFormat = $defaultHandler->getDefaultFormat();
1331
1332                         if ( $this->getContentModel() != $defaultModel ) {
1333                                 $t = $title->getPrefixedDBkey();
1334
1335                                 throw new MWException( "Can't save non-default content model with \$wgContentHandlerUseDB disabled: model is $model , default for $t is $defaultModel" );
1336                         }
1337
1338                         if ( $this->getContentFormat() != $defaultFormat ) {
1339                                 $t = $title->getPrefixedDBkey();
1340
1341                                 throw new MWException( "Can't use non-default content format with \$wgContentHandlerUseDB disabled: format is $format, default for $t is $defaultFormat" );
1342                         }
1343                 }
1344
1345                 $content = $this->getContent( Revision::RAW );
1346
1347                 if ( !$content->isValid() ) {
1348                         $t = $title->getPrefixedDBkey();
1349
1350                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1351                 }
1352         }
1353
1354         /**
1355          * Get the base 36 SHA-1 value for a string of text
1356          * @param $text String
1357          * @return String
1358          */
1359         public static function base36Sha1( $text ) {
1360                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1361         }
1362
1363         /**
1364          * Lazy-load the revision's text.
1365          * Currently hardcoded to the 'text' table storage engine.
1366          *
1367          * @return String
1368          */
1369         protected function loadText() {
1370                 wfProfileIn( __METHOD__ );
1371
1372                 // Caching may be beneficial for massive use of external storage
1373                 global $wgRevisionCacheExpiry, $wgMemc;
1374                 $textId = $this->getTextId();
1375                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1376                 if( $wgRevisionCacheExpiry ) {
1377                         $text = $wgMemc->get( $key );
1378                         if( is_string( $text ) ) {
1379                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1380                                 wfProfileOut( __METHOD__ );
1381                                 return $text;
1382                         }
1383                 }
1384
1385                 // If we kept data for lazy extraction, use it now...
1386                 if ( isset( $this->mTextRow ) ) {
1387                         $row = $this->mTextRow;
1388                         $this->mTextRow = null;
1389                 } else {
1390                         $row = null;
1391                 }
1392
1393                 if( !$row ) {
1394                         // Text data is immutable; check slaves first.
1395                         $dbr = wfGetDB( DB_SLAVE );
1396                         $row = $dbr->selectRow( 'text',
1397                                 array( 'old_text', 'old_flags' ),
1398                                 array( 'old_id' => $this->getTextId() ),
1399                                 __METHOD__ );
1400                 }
1401
1402                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1403                         // Possible slave lag!
1404                         $dbw = wfGetDB( DB_MASTER );
1405                         $row = $dbw->selectRow( 'text',
1406                                 array( 'old_text', 'old_flags' ),
1407                                 array( 'old_id' => $this->getTextId() ),
1408                                 __METHOD__ );
1409                 }
1410
1411                 $text = self::getRevisionText( $row );
1412
1413                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1414                 if( $wgRevisionCacheExpiry && $text !== false ) {
1415                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1416                 }
1417
1418                 wfProfileOut( __METHOD__ );
1419
1420                 return $text;
1421         }
1422
1423         /**
1424          * Create a new null-revision for insertion into a page's
1425          * history. This will not re-save the text, but simply refer
1426          * to the text from the previous version.
1427          *
1428          * Such revisions can for instance identify page rename
1429          * operations and other such meta-modifications.
1430          *
1431          * @param $dbw DatabaseBase
1432          * @param $pageId Integer: ID number of the page to read from
1433          * @param $summary String: revision's summary
1434          * @param $minor Boolean: whether the revision should be considered as minor
1435          * @return Revision|null on error
1436          */
1437         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1438                 global $wgContentHandlerUseDB;
1439
1440                 wfProfileIn( __METHOD__ );
1441
1442                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1443                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1444
1445                 if ( $wgContentHandlerUseDB ) {
1446                         $fields[] = 'rev_content_model';
1447                         $fields[] = 'rev_content_format';
1448                 }
1449
1450                 $current = $dbw->selectRow(
1451                         array( 'page', 'revision' ),
1452                         $fields,
1453                         array(
1454                                 'page_id' => $pageId,
1455                                 'page_latest=rev_id',
1456                                 ),
1457                         __METHOD__ );
1458
1459                 if( $current ) {
1460                         $row = array(
1461                                 'page'       => $pageId,
1462                                 'comment'    => $summary,
1463                                 'minor_edit' => $minor,
1464                                 'text_id'    => $current->rev_text_id,
1465                                 'parent_id'  => $current->page_latest,
1466                                 'len'        => $current->rev_len,
1467                                 'sha1'       => $current->rev_sha1
1468                         );
1469
1470                         if ( $wgContentHandlerUseDB ) {
1471                                 $row[ 'content_model' ] = $current->rev_content_model;
1472                                 $row[ 'content_format' ] = $current->rev_content_format;
1473                         }
1474
1475                         $revision = new Revision( $row );
1476                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1477                 } else {
1478                         $revision = null;
1479                 }
1480
1481                 wfProfileOut( __METHOD__ );
1482                 return $revision;
1483         }
1484
1485         /**
1486          * Determine if the current user is allowed to view a particular
1487          * field of this revision, if it's marked as deleted.
1488          *
1489          * @param $field Integer:one of self::DELETED_TEXT,
1490          *                              self::DELETED_COMMENT,
1491          *                              self::DELETED_USER
1492          * @param $user User object to check, or null to use $wgUser
1493          * @return Boolean
1494          */
1495         public function userCan( $field, User $user = null ) {
1496                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1497         }
1498
1499         /**
1500          * Determine if the current user is allowed to view a particular
1501          * field of this revision, if it's marked as deleted. This is used
1502          * by various classes to avoid duplication.
1503          *
1504          * @param $bitfield Integer: current field
1505          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1506          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1507          *                               self::DELETED_USER = File::DELETED_USER
1508          * @param $user User object to check, or null to use $wgUser
1509          * @return Boolean
1510          */
1511         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1512                 if( $bitfield & $field ) { // aspect is deleted
1513                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1514                                 $permission = 'suppressrevision';
1515                         } elseif ( $field & self::DELETED_TEXT ) {
1516                                 $permission = 'deletedtext';
1517                         } else {
1518                                 $permission = 'deletedhistory';
1519                         }
1520                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1521                         if ( $user === null ) {
1522                                 global $wgUser;
1523                                 $user = $wgUser;
1524                         }
1525                         return $user->isAllowed( $permission );
1526                 } else {
1527                         return true;
1528                 }
1529         }
1530
1531         /**
1532          * Get rev_timestamp from rev_id, without loading the rest of the row
1533          *
1534          * @param $title Title
1535          * @param $id Integer
1536          * @return String
1537          */
1538         static function getTimestampFromId( $title, $id ) {
1539                 $dbr = wfGetDB( DB_SLAVE );
1540                 // Casting fix for DB2
1541                 if ( $id == '' ) {
1542                         $id = 0;
1543                 }
1544                 $conds = array( 'rev_id' => $id );
1545                 $conds['rev_page'] = $title->getArticleID();
1546                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1547                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1548                         # Not in slave, try master
1549                         $dbw = wfGetDB( DB_MASTER );
1550                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1551                 }
1552                 return wfTimestamp( TS_MW, $timestamp );
1553         }
1554
1555         /**
1556          * Get count of revisions per page...not very efficient
1557          *
1558          * @param $db DatabaseBase
1559          * @param $id Integer: page id
1560          * @return Integer
1561          */
1562         static function countByPageId( $db, $id ) {
1563                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1564                         array( 'rev_page' => $id ), __METHOD__ );
1565                 if( $row ) {
1566                         return $row->revCount;
1567                 }
1568                 return 0;
1569         }
1570
1571         /**
1572          * Get count of revisions per page...not very efficient
1573          *
1574          * @param $db DatabaseBase
1575          * @param $title Title
1576          * @return Integer
1577          */
1578         static function countByTitle( $db, $title ) {
1579                 $id = $title->getArticleID();
1580                 if( $id ) {
1581                         return self::countByPageId( $db, $id );
1582                 }
1583                 return 0;
1584         }
1585 }