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
  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
 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( $row->ar_text ) && !$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::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 283                 $rev = self::loadFromConds( $db, $conditions, $flags );
 284                 if ( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 285                         if ( !( $flags & self::READ_LATEST ) ) {
 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::READ_LOCKING ) == self::READ_LOCKING ) {
 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          * @throws MWException
 476          * @access private
 477          */
 478         function __construct( $row ) {
 479                 if( is_object( $row ) ) {
 480                         $this->mId        = intval( $row->rev_id );
 481                         $this->mPage      = intval( $row->rev_page );
 482                         $this->mTextId    = intval( $row->rev_text_id );
 483                         $this->mComment   =         $row->rev_comment;
 484                         $this->mUser      = intval( $row->rev_user );
 485                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 486                         $this->mTimestamp =         $row->rev_timestamp;
 487                         $this->mDeleted   = intval( $row->rev_deleted );
 488
 489                         if( !isset( $row->rev_parent_id ) ) {
 490                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 491                         } else {
 492                                 $this->mParentId  = intval( $row->rev_parent_id );
 493                         }
 494
 495                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 496                                 $this->mSize = null;
 497                         } else {
 498                                 $this->mSize = intval( $row->rev_len );
 499                         }
 500
 501                         if ( !isset( $row->rev_sha1 ) ) {
 502                                 $this->mSha1 = null;
 503                         } else {
 504                                 $this->mSha1 = $row->rev_sha1;
 505                         }
 506
 507                         if( isset( $row->page_latest ) ) {
 508                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 509                                 $this->mTitle = Title::newFromRow( $row );
 510                         } else {
 511                                 $this->mCurrent = false;
 512                                 $this->mTitle = null;
 513                         }
 514
 515                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 516                                 $this->mContentModel = null; # determine on demand if needed
 517                         } else {
 518                                 $this->mContentModel = strval( $row->rev_content_model );
 519                         }
 520
 521                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 522                                 $this->mContentFormat = null; # determine on demand if needed
 523                         } else {
 524                                 $this->mContentFormat = strval( $row->rev_content_format );
 525                         }
 526
 527                         // Lazy extraction...
 528                         $this->mText      = null;
 529                         if( isset( $row->old_text ) ) {
 530                                 $this->mTextRow = $row;
 531                         } else {
 532                                 // 'text' table row entry will be lazy-loaded
 533                                 $this->mTextRow = null;
 534                         }
 535
 536                         // Use user_name for users and rev_user_text for IPs...
 537                         $this->mUserText = null; // lazy load if left null
 538                         if ( $this->mUser == 0 ) {
 539                                 $this->mUserText = $row->rev_user_text; // IP user
 540                         } elseif ( isset( $row->user_name ) ) {
 541                                 $this->mUserText = $row->user_name; // logged-in user
 542                         }
 543                         $this->mOrigUserText = $row->rev_user_text;
 544                 } elseif( is_array( $row ) ) {
 545                         // Build a new revision to be saved...
 546                         global $wgUser; // ugh
 547
 548
 549                         # if we have a content object, use it to set the model and type
 550                         if ( !empty( $row['content'] ) ) {
 551                                 //@todo: when is that set? test with external store setup! check out insertOn() [dk]
 552                                 if ( !empty( $row['text_id'] ) ) {
 553                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), "
 554                                                                                         . "can't serialize content object" );
 555                                 }
 556
 557                                 $row['content_model'] = $row['content']->getModel();
 558                                 # note: mContentFormat is initializes later accordingly
 559                                 # note: content is serialized later in this method!
 560                                 # also set text to null?
 561                         }
 562
 563                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 564                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 565                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 566                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 567                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 568                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 569                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 570                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 571                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 572                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 573                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 574
 575                         $this->mContentModel   = isset( $row['content_model']  )  ? strval( $row['content_model'] )  : null;
 576                         $this->mContentFormat  = isset( $row['content_format']  ) ? strval( $row['content_format'] ) : null;
 577
 578                         // Enforce spacing trimming on supplied text
 579                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 580                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 581                         $this->mTextRow   = null;
 582
 583                         $this->mTitle     = isset( $row['title']      ) ? $row['title'] : null;
 584
 585                         // if we have a Content object, override mText and mContentModel
 586                         if ( !empty( $row['content'] ) ) {
 587                                 if ( !( $row['content'] instanceof Content ) ) {
 588                                         throw new MWException( '`content` field must contain a Content object.' );
 589                                 }
 590
 591                                 $handler = $this->getContentHandler();
 592                                 $this->mContent = $row['content'];
 593
 594                                 $this->mContentModel = $this->mContent->getModel();
 595                                 $this->mContentHandler = null;
 596
 597                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 598                         } elseif ( !is_null( $this->mText ) ) {
 599                                 $handler = $this->getContentHandler();
 600                                 $this->mContent = $handler->unserializeContent( $this->mText );
 601                         }
 602
 603                         // if we have a Title object, override mPage. Useful for testing and convenience.
 604                         if ( isset( $row['title'] ) ) {
 605                                 $this->mTitle     = $row['title'];
 606                                 $this->mPage      = $this->mTitle->getArticleID();
 607                         } else {
 608                                 $this->mTitle     = null; // Load on demand if needed
 609                         }
 610
 611                         // @todo: XXX: really? we are about to create a revision. it will usually then be the current one.
 612                         $this->mCurrent   = false;
 613
 614                         // If we still have no length, see it we have the text to figure it out
 615                         if ( !$this->mSize ) {
 616                                 if ( !is_null( $this->mContent ) ) {
 617                                         $this->mSize = $this->mContent->getSize();
 618                                 } else {
 619                                         #NOTE: this should never happen if we have either text or content object!
 620                                         $this->mSize = null;
 621                                 }
 622                         }
 623
 624                         // Same for sha1
 625                         if ( $this->mSha1 === null ) {
 626                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 627                         }
 628
 629                         // force lazy init
 630                         $this->getContentModel();
 631                         $this->getContentFormat();
 632                 } else {
 633                         throw new MWException( 'Revision constructor passed invalid row format.' );
 634                 }
 635                 $this->mUnpatrolled = null;
 636         }
 637
 638         /**
 639          * Get revision ID
 640          *
 641          * @return Integer|null
 642          */
 643         public function getId() {
 644                 return $this->mId;
 645         }
 646
 647         /**
 648          * Set the revision ID
 649          *
 650          * @since 1.19
 651          * @param $id Integer
 652          */
 653         public function setId( $id ) {
 654                 $this->mId = $id;
 655         }
 656
 657         /**
 658          * Get text row ID
 659          *
 660          * @return Integer|null
 661          */
 662         public function getTextId() {
 663                 return $this->mTextId;
 664         }
 665
 666         /**
 667          * Get parent revision ID (the original previous page revision)
 668          *
 669          * @return Integer|null
 670          */
 671         public function getParentId() {
 672                 return $this->mParentId;
 673         }
 674
 675         /**
 676          * Returns the length of the text in this revision, or null if unknown.
 677          *
 678          * @return Integer|null
 679          */
 680         public function getSize() {
 681                 return $this->mSize;
 682         }
 683
 684         /**
 685          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 686          *
 687          * @return String|null
 688          */
 689         public function getSha1() {
 690                 return $this->mSha1;
 691         }
 692
 693         /**
 694          * Returns the title of the page associated with this entry or null.
 695          *
 696          * Will do a query, when title is not set and id is given.
 697          *
 698          * @return Title|null
 699          */
 700         public function getTitle() {
 701                 if( isset( $this->mTitle ) ) {
 702                         return $this->mTitle;
 703                 }
 704                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 705                         $dbr = wfGetDB( DB_SLAVE );
 706                         $row = $dbr->selectRow(
 707                                 array( 'page', 'revision' ),
 708                                 self::selectPageFields(),
 709                                 array( 'page_id=rev_page',
 710                                            'rev_id' => $this->mId ),
 711                                 __METHOD__ );
 712                         if ( $row ) {
 713                                 $this->mTitle = Title::newFromRow( $row );
 714                         }
 715                 }
 716
 717                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 718                         $this->mTitle = Title::newFromID( $this->mPage );
 719                 }
 720
 721                 return $this->mTitle;
 722         }
 723
 724         /**
 725          * Set the title of the revision
 726          *
 727          * @param $title Title
 728          */
 729         public function setTitle( $title ) {
 730                 $this->mTitle = $title;
 731         }
 732
 733         /**
 734          * Get the page ID
 735          *
 736          * @return Integer|null
 737          */
 738         public function getPage() {
 739                 return $this->mPage;
 740         }
 741
 742         /**
 743          * Fetch revision's user id if it's available to the specified audience.
 744          * If the specified audience does not have access to it, zero will be
 745          * returned.
 746          *
 747          * @param $audience Integer: one of:
 748          *      Revision::FOR_PUBLIC       to be displayed to all users
 749          *      Revision::FOR_THIS_USER    to be displayed to the given user
 750          *      Revision::RAW              get the ID regardless of permissions
 751          * @param $user User object to check for, only if FOR_THIS_USER is passed
 752          *              to the $audience parameter
 753          * @return Integer
 754          */
 755         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 756                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 757                         return 0;
 758                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 759                         return 0;
 760                 } else {
 761                         return $this->mUser;
 762                 }
 763         }
 764
 765         /**
 766          * Fetch revision's user id without regard for the current user's permissions
 767          *
 768          * @return String
 769          */
 770         public function getRawUser() {
 771                 return $this->mUser;
 772         }
 773
 774         /**
 775          * Fetch revision's username if it's available to the specified audience.
 776          * If the specified audience does not have access to the username, an
 777          * empty string will be returned.
 778          *
 779          * @param $audience Integer: one of:
 780          *      Revision::FOR_PUBLIC       to be displayed to all users
 781          *      Revision::FOR_THIS_USER    to be displayed to the given user
 782          *      Revision::RAW              get the text regardless of permissions
 783          * @param $user User object to check for, only if FOR_THIS_USER is passed
 784          *              to the $audience parameter
 785          * @return string
 786          */
 787         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 788                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 789                         return '';
 790                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 791                         return '';
 792                 } else {
 793                         return $this->getRawUserText();
 794                 }
 795         }
 796
 797         /**
 798          * Fetch revision's username without regard for view restrictions
 799          *
 800          * @return String
 801          */
 802         public function getRawUserText() {
 803                 if ( $this->mUserText === null ) {
 804                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 805                         if ( $this->mUserText === false ) {
 806                                 # This shouldn't happen, but it can if the wiki was recovered
 807                                 # via importing revs and there is no user table entry yet.
 808                                 $this->mUserText = $this->mOrigUserText;
 809                         }
 810                 }
 811                 return $this->mUserText;
 812         }
 813
 814         /**
 815          * Fetch revision comment if it's available to the specified audience.
 816          * If the specified audience does not have access to the comment, an
 817          * empty string will be returned.
 818          *
 819          * @param $audience Integer: one of:
 820          *      Revision::FOR_PUBLIC       to be displayed to all users
 821          *      Revision::FOR_THIS_USER    to be displayed to the given user
 822          *      Revision::RAW              get the text regardless of permissions
 823          * @param $user User object to check for, only if FOR_THIS_USER is passed
 824          *              to the $audience parameter
 825          * @return String
 826          */
 827         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 828                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 829                         return '';
 830                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 831                         return '';
 832                 } else {
 833                         return $this->mComment;
 834                 }
 835         }
 836
 837         /**
 838          * Fetch revision comment without regard for the current user's permissions
 839          *
 840          * @return String
 841          */
 842         public function getRawComment() {
 843                 return $this->mComment;
 844         }
 845
 846         /**
 847          * @return Boolean
 848          */
 849         public function isMinor() {
 850                 return (bool)$this->mMinorEdit;
 851         }
 852
 853         /**
 854          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 855          */
 856         public function isUnpatrolled() {
 857                 if( $this->mUnpatrolled !== null ) {
 858                         return $this->mUnpatrolled;
 859                 }
 860                 $dbr = wfGetDB( DB_SLAVE );
 861                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 862                         'rc_id',
 863                         array( // Add redundant user,timestamp condition so we can use the existing index
 864                                 'rc_user_text'  => $this->getRawUserText(),
 865                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 866                                 'rc_this_oldid' => $this->getId(),
 867                                 'rc_patrolled'  => 0
 868                         ),
 869                         __METHOD__
 870                 );
 871                 return (int)$this->mUnpatrolled;
 872         }
 873
 874         /**
 875          * @param $field int one of DELETED_* bitfield constants
 876          *
 877          * @return Boolean
 878          */
 879         public function isDeleted( $field ) {
 880                 return ( $this->mDeleted & $field ) == $field;
 881         }
 882
 883         /**
 884          * Get the deletion bitfield of the revision
 885          *
 886          * @return int
 887          */
 888         public function getVisibility() {
 889                 return (int)$this->mDeleted;
 890         }
 891
 892         /**
 893          * Fetch revision text if it's available to the specified audience.
 894          * If the specified audience does not have the ability to view this
 895          * revision, an empty string will be returned.
 896          *
 897          * @param $audience Integer: one of:
 898          *      Revision::FOR_PUBLIC       to be displayed to all users
 899          *      Revision::FOR_THIS_USER    to be displayed to the given user
 900          *      Revision::RAW              get the text regardless of permissions
 901          * @param $user User object to check for, only if FOR_THIS_USER is passed
 902          *              to the $audience parameter
 903          *
 904          * @deprecated in 1.21, use getContent() instead
 905          * @todo: replace usage in core
 906          * @return String
 907          */
 908         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 909                 ContentHandler::deprecated( __METHOD__, '1.21' );
 910
 911                 $content = $this->getContent( $audience, $user );
 912                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 913         }
 914
 915         /**
 916          * Fetch revision content if it's available to the specified audience.
 917          * If the specified audience does not have the ability to view this
 918          * revision, null will be returned.
 919          *
 920          * @param $audience Integer: one of:
 921          *      Revision::FOR_PUBLIC       to be displayed to all users
 922          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 923          *      Revision::RAW              get the text regardless of permissions
 924          * @param $user User object to check for, only if FOR_THIS_USER is passed
 925          *              to the $audience parameter
 926          * @since 1.21
 927          * @return Content|null
 928          */
 929         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 930                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 931                         return null;
 932                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 933                         return null;
 934                 } else {
 935                         return $this->getContentInternal();
 936                 }
 937         }
 938
 939         /**
 940          * Alias for getText(Revision::FOR_THIS_USER)
 941          *
 942          * @deprecated since 1.17
 943          * @return String
 944          */
 945         public function revText() {
 946                 wfDeprecated( __METHOD__, '1.17' );
 947                 return $this->getText( self::FOR_THIS_USER );
 948         }
 949
 950         /**
 951          * Fetch revision text without regard for view restrictions
 952          *
 953          * @return String
 954          *
 955          * @deprecated since 1.21. Instead, use Revision::getContent( Revision::RAW )
 956          *                         or Revision::getSerializedData() as appropriate.
 957          */
 958         public function getRawText() {
 959                 ContentHandler::deprecated( __METHOD__, "1.21" );
 960                 return $this->getText( self::RAW );
 961         }
 962
 963         /**
 964          * Fetch original serialized data without regard for view restrictions
 965          *
 966          * @since 1.21
 967          * @return String
 968          */
 969         public function getSerializedData() {
 970                 return $this->mText;
 971         }
 972
 973         /**
 974          * Gets the content object for the revision
 975          *
 976          * @since 1.21
 977          * @return Content
 978          */
 979         protected function getContentInternal() {
 980                 if( is_null( $this->mContent ) ) {
 981                         // Revision is immutable. Load on demand:
 982
 983                         $handler = $this->getContentHandler();
 984                         $format = $this->getContentFormat();
 985
 986                         if( is_null( $this->mText ) ) {
 987                                 // Load text on demand:
 988                                 $this->mText = $this->loadText();
 989                         }
 990
 991                         $this->mContent = is_null( $this->mText ) ? null : $handler->unserializeContent( $this->mText, $format );
 992                 }
 993
 994                 return $this->mContent->copy(); // NOTE: copy() will return $this for immutable content objects
 995         }
 996
 997         /**
 998          * Returns the content model for this revision.
 999          *
1000          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
1001          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1002          * is used as a last resort.
1003          *
1004          * @return String the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
1005          **/
1006         public function getContentModel() {
1007                 if ( !$this->mContentModel ) {
1008                         $title = $this->getTitle();
1009                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
1010
1011                         assert( !empty( $this->mContentModel ) );
1012                 }
1013
1014                 return $this->mContentModel;
1015         }
1016
1017         /**
1018          * Returns the content format for this revision.
1019          *
1020          * If no content format was stored in the database, the default format for this
1021          * revision's content model is returned.
1022          *
1023          * @return String the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
1024          **/
1025         public function getContentFormat() {
1026                 if ( !$this->mContentFormat ) {
1027                         $handler = $this->getContentHandler();
1028                         $this->mContentFormat = $handler->getDefaultFormat();
1029
1030                         assert( !empty( $this->mContentFormat ) );
1031                 }
1032
1033                 return $this->mContentFormat;
1034         }
1035
1036         /**
1037          * Returns the content handler appropriate for this revision's content model.
1038          *
1039          * @throws MWException
1040          * @return ContentHandler
1041          */
1042         public function getContentHandler() {
1043                 if ( !$this->mContentHandler ) {
1044                         $model = $this->getContentModel();
1045                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1046
1047                         $format = $this->getContentFormat();
1048
1049                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1050                                 throw new MWException( "Oops, the content format $format is not supported for this content model, $model" );
1051                         }
1052                 }
1053
1054                 return $this->mContentHandler;
1055         }
1056
1057         /**
1058          * @return String
1059          */
1060         public function getTimestamp() {
1061                 return wfTimestamp( TS_MW, $this->mTimestamp );
1062         }
1063
1064         /**
1065          * @return Boolean
1066          */
1067         public function isCurrent() {
1068                 return $this->mCurrent;
1069         }
1070
1071         /**
1072          * Get previous revision for this title
1073          *
1074          * @return Revision or null
1075          */
1076         public function getPrevious() {
1077                 if( $this->getTitle() ) {
1078                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1079                         if( $prev ) {
1080                                 return self::newFromTitle( $this->getTitle(), $prev );
1081                         }
1082                 }
1083                 return null;
1084         }
1085
1086         /**
1087          * Get next revision for this title
1088          *
1089          * @return Revision or null
1090          */
1091         public function getNext() {
1092                 if( $this->getTitle() ) {
1093                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1094                         if ( $next ) {
1095                                 return self::newFromTitle( $this->getTitle(), $next );
1096                         }
1097                 }
1098                 return null;
1099         }
1100
1101         /**
1102          * Get previous revision Id for this page_id
1103          * This is used to populate rev_parent_id on save
1104          *
1105          * @param $db DatabaseBase
1106          * @return Integer
1107          */
1108         private function getPreviousRevisionId( $db ) {
1109                 if( is_null( $this->mPage ) ) {
1110                         return 0;
1111                 }
1112                 # Use page_latest if ID is not given
1113                 if( !$this->mId ) {
1114                         $prevId = $db->selectField( 'page', 'page_latest',
1115                                 array( 'page_id' => $this->mPage ),
1116                                 __METHOD__ );
1117                 } else {
1118                         $prevId = $db->selectField( 'revision', 'rev_id',
1119                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1120                                 __METHOD__,
1121                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1122                 }
1123                 return intval( $prevId );
1124         }
1125
1126         /**
1127           * Get revision text associated with an old or archive row
1128           * $row is usually an object from wfFetchRow(), both the flags and the text
1129           * field must be included
1130           *
1131           * @param $row Object: the text data
1132           * @param $prefix String: table prefix (default 'old_')
1133           * @return String: text the text requested or false on failure
1134           */
1135         public static function getRevisionText( $row, $prefix = 'old_' ) {
1136                 wfProfileIn( __METHOD__ );
1137
1138                 # Get data
1139                 $textField = $prefix . 'text';
1140                 $flagsField = $prefix . 'flags';
1141
1142                 if( isset( $row->$flagsField ) ) {
1143                         $flags = explode( ',', $row->$flagsField );
1144                 } else {
1145                         $flags = array();
1146                 }
1147
1148                 if( isset( $row->$textField ) ) {
1149                         $text = $row->$textField;
1150                 } else {
1151                         wfProfileOut( __METHOD__ );
1152                         return false;
1153                 }
1154
1155                 # Use external methods for external objects, text in table is URL-only then
1156                 if ( in_array( 'external', $flags ) ) {
1157                         $url = $text;
1158                         $parts = explode( '://', $url, 2 );
1159                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1160                                 wfProfileOut( __METHOD__ );
1161                                 return false;
1162                         }
1163                         $text = ExternalStore::fetchFromURL( $url );
1164                 }
1165
1166                 // If the text was fetched without an error, convert it
1167                 if ( $text !== false ) {
1168                         if( in_array( 'gzip', $flags ) ) {
1169                                 # Deal with optional compression of archived pages.
1170                                 # This can be done periodically via maintenance/compressOld.php, and
1171                                 # as pages are saved if $wgCompressRevisions is set.
1172                                 $text = gzinflate( $text );
1173                         }
1174
1175                         if( in_array( 'object', $flags ) ) {
1176                                 # Generic compressed storage
1177                                 $obj = unserialize( $text );
1178                                 if ( !is_object( $obj ) ) {
1179                                         // Invalid object
1180                                         wfProfileOut( __METHOD__ );
1181                                         return false;
1182                                 }
1183                                 $text = $obj->getText();
1184                         }
1185
1186                         global $wgLegacyEncoding;
1187                         if( $text !== false && $wgLegacyEncoding
1188                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1189                         {
1190                                 # Old revisions kept around in a legacy encoding?
1191                                 # Upconvert on demand.
1192                                 # ("utf8" checked for compatibility with some broken
1193                                 #  conversion scripts 2008-12-30)
1194                                 global $wgContLang;
1195                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1196                         }
1197                 }
1198                 wfProfileOut( __METHOD__ );
1199                 return $text;
1200         }
1201
1202         /**
1203          * If $wgCompressRevisions is enabled, we will compress data.
1204          * The input string is modified in place.
1205          * Return value is the flags field: contains 'gzip' if the
1206          * data is compressed, and 'utf-8' if we're saving in UTF-8
1207          * mode.
1208          *
1209          * @param $text Mixed: reference to a text
1210          * @return String
1211          */
1212         public static function compressRevisionText( &$text ) {
1213                 global $wgCompressRevisions;
1214                 $flags = array();
1215
1216                 # Revisions not marked this way will be converted
1217                 # on load if $wgLegacyCharset is set in the future.
1218                 $flags[] = 'utf-8';
1219
1220                 if( $wgCompressRevisions ) {
1221                         if( function_exists( 'gzdeflate' ) ) {
1222                                 $text = gzdeflate( $text );
1223                                 $flags[] = 'gzip';
1224                         } else {
1225                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1226                         }
1227                 }
1228                 return implode( ',', $flags );
1229         }
1230
1231         /**
1232          * Insert a new revision into the database, returning the new revision ID
1233          * number on success and dies horribly on failure.
1234          *
1235          * @param $dbw DatabaseBase: (master connection)
1236          * @throws MWException
1237          * @return Integer
1238          */
1239         public function insertOn( $dbw ) {
1240                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1241
1242                 wfProfileIn( __METHOD__ );
1243
1244                 $this->checkContentModel();
1245
1246                 $data = $this->mText;
1247                 $flags = self::compressRevisionText( $data );
1248
1249                 # Write to external storage if required
1250                 if( $wgDefaultExternalStore ) {
1251                         // Store and get the URL
1252                         $data = ExternalStore::insertToDefault( $data );
1253                         if( !$data ) {
1254                                 throw new MWException( "Unable to store text to external storage" );
1255                         }
1256                         if( $flags ) {
1257                                 $flags .= ',';
1258                         }
1259                         $flags .= 'external';
1260                 }
1261
1262                 # Record the text (or external storage URL) to the text table
1263                 if( !isset( $this->mTextId ) ) {
1264                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1265                         $dbw->insert( 'text',
1266                                 array(
1267                                         'old_id'    => $old_id,
1268                                         'old_text'  => $data,
1269                                         'old_flags' => $flags,
1270                                 ), __METHOD__
1271                         );
1272                         $this->mTextId = $dbw->insertId();
1273                 }
1274
1275                 if ( $this->mComment === null ) $this->mComment = "";
1276
1277                 # Record the edit in revisions
1278                 $rev_id = isset( $this->mId )
1279                         ? $this->mId
1280                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1281                 $row = array(
1282                         'rev_id'         => $rev_id,
1283                         'rev_page'       => $this->mPage,
1284                         'rev_text_id'    => $this->mTextId,
1285                         'rev_comment'    => $this->mComment,
1286                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1287                         'rev_user'       => $this->mUser,
1288                         'rev_user_text'  => $this->mUserText,
1289                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1290                         'rev_deleted'    => $this->mDeleted,
1291                         'rev_len'        => $this->mSize,
1292                         'rev_parent_id'  => is_null( $this->mParentId )
1293                                 ? $this->getPreviousRevisionId( $dbw )
1294                                 : $this->mParentId,
1295                         'rev_sha1'       => is_null( $this->mSha1 )
1296                                 ? Revision::base36Sha1( $this->mText )
1297                                 : $this->mSha1,
1298                 );
1299
1300                 if ( $wgContentHandlerUseDB ) {
1301                         //NOTE: Store null for the default model and format, to save space.
1302                         //XXX: Makes the DB sensitive to changed defaults. Make this behaviour optional? Only in miser mode?
1303
1304                         $model = $this->getContentModel();
1305                         $format = $this->getContentFormat();
1306
1307                         $title = $this->getTitle();
1308
1309                         if ( $title === null ) {
1310                                 throw new MWException( "Insufficient information to determine the title of the revision's page!" );
1311                         }
1312
1313                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1314                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1315
1316                         $row[ 'rev_content_model' ] = ( $model === $defaultModel ) ? null : $model;
1317                         $row[ 'rev_content_format' ] = ( $format === $defaultFormat ) ? null : $format;
1318                 }
1319
1320                 $dbw->insert( 'revision', $row, __METHOD__ );
1321
1322                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1323
1324                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1325
1326                 wfProfileOut( __METHOD__ );
1327                 return $this->mId;
1328         }
1329
1330         protected function checkContentModel() {
1331                 global $wgContentHandlerUseDB;
1332
1333                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1334
1335                 $model = $this->getContentModel();
1336                 $format = $this->getContentFormat();
1337                 $handler = $this->getContentHandler();
1338
1339                 if ( !$handler->isSupportedFormat( $format ) ) {
1340                         $t = $title->getPrefixedDBkey();
1341
1342                         throw new MWException( "Can't use format $format with content model $model on $t" );
1343                 }
1344
1345                 if ( !$wgContentHandlerUseDB && $title ) {
1346                         // if $wgContentHandlerUseDB is not set, all revisions must use the default content model and format.
1347
1348                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1349                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1350                         $defaultFormat = $defaultHandler->getDefaultFormat();
1351
1352                         if ( $this->getContentModel() != $defaultModel ) {
1353                                 $t = $title->getPrefixedDBkey();
1354
1355                                 throw new MWException( "Can't save non-default content model with \$wgContentHandlerUseDB disabled: "
1356                                                                                 . "model is $model , default for $t is $defaultModel" );
1357                         }
1358
1359                         if ( $this->getContentFormat() != $defaultFormat ) {
1360                                 $t = $title->getPrefixedDBkey();
1361
1362                                 throw new MWException( "Can't use non-default content format with \$wgContentHandlerUseDB disabled: "
1363                                                                                 . "format is $format, default for $t is $defaultFormat" );
1364                         }
1365                 }
1366
1367                 $content = $this->getContent( Revision::RAW );
1368
1369                 if ( !$content->isValid() ) {
1370                         $t = $title->getPrefixedDBkey();
1371
1372                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1373                 }
1374         }
1375
1376         /**
1377          * Get the base 36 SHA-1 value for a string of text
1378          * @param $text String
1379          * @return String
1380          */
1381         public static function base36Sha1( $text ) {
1382                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1383         }
1384
1385         /**
1386          * Lazy-load the revision's text.
1387          * Currently hardcoded to the 'text' table storage engine.
1388          *
1389          * @return String
1390          */
1391         protected function loadText() {
1392                 wfProfileIn( __METHOD__ );
1393
1394                 // Caching may be beneficial for massive use of external storage
1395                 global $wgRevisionCacheExpiry, $wgMemc;
1396                 $textId = $this->getTextId();
1397                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1398                 if( $wgRevisionCacheExpiry ) {
1399                         $text = $wgMemc->get( $key );
1400                         if( is_string( $text ) ) {
1401                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1402                                 wfProfileOut( __METHOD__ );
1403                                 return $text;
1404                         }
1405                 }
1406
1407                 // If we kept data for lazy extraction, use it now...
1408                 if ( isset( $this->mTextRow ) ) {
1409                         $row = $this->mTextRow;
1410                         $this->mTextRow = null;
1411                 } else {
1412                         $row = null;
1413                 }
1414
1415                 if( !$row ) {
1416                         // Text data is immutable; check slaves first.
1417                         $dbr = wfGetDB( DB_SLAVE );
1418                         $row = $dbr->selectRow( 'text',
1419                                 array( 'old_text', 'old_flags' ),
1420                                 array( 'old_id' => $this->getTextId() ),
1421                                 __METHOD__ );
1422                 }
1423
1424                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1425                         // Possible slave lag!
1426                         $dbw = wfGetDB( DB_MASTER );
1427                         $row = $dbw->selectRow( 'text',
1428                                 array( 'old_text', 'old_flags' ),
1429                                 array( 'old_id' => $this->getTextId() ),
1430                                 __METHOD__ );
1431                 }
1432
1433                 $text = self::getRevisionText( $row );
1434
1435                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1436                 if( $wgRevisionCacheExpiry && $text !== false ) {
1437                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1438                 }
1439
1440                 wfProfileOut( __METHOD__ );
1441
1442                 return $text;
1443         }
1444
1445         /**
1446          * Create a new null-revision for insertion into a page's
1447          * history. This will not re-save the text, but simply refer
1448          * to the text from the previous version.
1449          *
1450          * Such revisions can for instance identify page rename
1451          * operations and other such meta-modifications.
1452          *
1453          * @param $dbw DatabaseBase
1454          * @param $pageId Integer: ID number of the page to read from
1455          * @param $summary String: revision's summary
1456          * @param $minor Boolean: whether the revision should be considered as minor
1457          * @return Revision|null on error
1458          */
1459         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1460                 global $wgContentHandlerUseDB;
1461
1462                 wfProfileIn( __METHOD__ );
1463
1464                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1465                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1466
1467                 if ( $wgContentHandlerUseDB ) {
1468                         $fields[] = 'rev_content_model';
1469                         $fields[] = 'rev_content_format';
1470                 }
1471
1472                 $current = $dbw->selectRow(
1473                         array( 'page', 'revision' ),
1474                         $fields,
1475                         array(
1476                                 'page_id' => $pageId,
1477                                 'page_latest=rev_id',
1478                                 ),
1479                         __METHOD__ );
1480
1481                 if( $current ) {
1482                         $row = array(
1483                                 'page'       => $pageId,
1484                                 'comment'    => $summary,
1485                                 'minor_edit' => $minor,
1486                                 'text_id'    => $current->rev_text_id,
1487                                 'parent_id'  => $current->page_latest,
1488                                 'len'        => $current->rev_len,
1489                                 'sha1'       => $current->rev_sha1
1490                         );
1491
1492                         if ( $wgContentHandlerUseDB ) {
1493                                 $row[ 'content_model' ] = $current->rev_content_model;
1494                                 $row[ 'content_format' ] = $current->rev_content_format;
1495                         }
1496
1497                         $revision = new Revision( $row );
1498                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1499                 } else {
1500                         $revision = null;
1501                 }
1502
1503                 wfProfileOut( __METHOD__ );
1504                 return $revision;
1505         }
1506
1507         /**
1508          * Determine if the current user is allowed to view a particular
1509          * field of this revision, if it's marked as deleted.
1510          *
1511          * @param $field Integer:one of self::DELETED_TEXT,
1512          *                              self::DELETED_COMMENT,
1513          *                              self::DELETED_USER
1514          * @param $user User object to check, or null to use $wgUser
1515          * @return Boolean
1516          */
1517         public function userCan( $field, User $user = null ) {
1518                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1519         }
1520
1521         /**
1522          * Determine if the current user is allowed to view a particular
1523          * field of this revision, if it's marked as deleted. This is used
1524          * by various classes to avoid duplication.
1525          *
1526          * @param $bitfield Integer: current field
1527          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1528          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1529          *                               self::DELETED_USER = File::DELETED_USER
1530          * @param $user User object to check, or null to use $wgUser
1531          * @return Boolean
1532          */
1533         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1534                 if( $bitfield & $field ) { // aspect is deleted
1535                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1536                                 $permission = 'suppressrevision';
1537                         } elseif ( $field & self::DELETED_TEXT ) {
1538                                 $permission = 'deletedtext';
1539                         } else {
1540                                 $permission = 'deletedhistory';
1541                         }
1542                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1543                         if ( $user === null ) {
1544                                 global $wgUser;
1545                                 $user = $wgUser;
1546                         }
1547                         return $user->isAllowed( $permission );
1548                 } else {
1549                         return true;
1550                 }
1551         }
1552
1553         /**
1554          * Get rev_timestamp from rev_id, without loading the rest of the row
1555          *
1556          * @param $title Title
1557          * @param $id Integer
1558          * @return String
1559          */
1560         static function getTimestampFromId( $title, $id ) {
1561                 $dbr = wfGetDB( DB_SLAVE );
1562                 // Casting fix for DB2
1563                 if ( $id == '' ) {
1564                         $id = 0;
1565                 }
1566                 $conds = array( 'rev_id' => $id );
1567                 $conds['rev_page'] = $title->getArticleID();
1568                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1569                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1570                         # Not in slave, try master
1571                         $dbw = wfGetDB( DB_MASTER );
1572                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1573                 }
1574                 return wfTimestamp( TS_MW, $timestamp );
1575         }
1576
1577         /**
1578          * Get count of revisions per page...not very efficient
1579          *
1580          * @param $db DatabaseBase
1581          * @param $id Integer: page id
1582          * @return Integer
1583          */
1584         static function countByPageId( $db, $id ) {
1585                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1586                         array( 'rev_page' => $id ), __METHOD__ );
1587                 if( $row ) {
1588                         return $row->revCount;
1589                 }
1590                 return 0;
1591         }
1592
1593         /**
1594          * Get count of revisions per page...not very efficient
1595          *
1596          * @param $db DatabaseBase
1597          * @param $title Title
1598          * @return Integer
1599          */
1600         static function countByTitle( $db, $title ) {
1601                 $id = $title->getArticleID();
1602                 if( $id ) {
1603                         return self::countByPageId( $db, $id );
1604                 }
1605                 return 0;
1606         }
1607
1608         /**
1609          * Check if no edits were made by other users since
1610          * the time a user started editing the page. Limit to
1611          * 50 revisions for the sake of performance.
1612          *
1613          * @since 1.20
1614          *
1615          * @param DatabaseBase|int $db the Database to perform the check on. May be given as a Database object or
1616          *        a database identifier usable with wfGetDB.
1617          * @param int $pageId the ID of the page in question
1618          * @param int $userId the ID of the user in question
1619          * @param string $since look at edits since this time
1620          *
1621          * @return bool True if the given user was the only one to edit since the given timestamp
1622          */
1623         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1624                 if ( !$userId ) return false;
1625
1626                 if ( is_int( $db ) ) {
1627                         $db = wfGetDB( $db );
1628                 }
1629
1630                 $res = $db->select( 'revision',
1631                         'rev_user',
1632                         array(
1633                                 'rev_page' => $pageId,
1634                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1635                         ),
1636                         __METHOD__,
1637                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1638                 foreach ( $res as $row ) {
1639                         if ( $row->rev_user != $userId ) {
1640                                 return false;
1641                         }
1642                 }
1643                 return true;
1644         }
1645 }