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 {
  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 Revision::getText()
  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          * @param $id Integer
  64          * @return Revision or null
  65          */
  66         public static function newFromId( $id ) {
  67                 return Revision::newFromConds( array( 'rev_id' => intval( $id ) ) );
  68         }
  69
  70         /**
  71          * Load either the current, or a specified, revision
  72          * that's attached to a given title. If not attached
  73          * to that title, will return null.
  74          *
  75          * @param $title Title
  76          * @param $id Integer (optional)
  77          * @return Revision or null
  78          */
  79         public static function newFromTitle( $title, $id = 0 ) {
  80                 $conds = array(
  81                         'page_namespace' => $title->getNamespace(),
  82                         'page_title'     => $title->getDBkey()
  83                 );
  84                 if ( $id ) {
  85                         // Use the specified ID
  86                         $conds['rev_id'] = $id;
  87                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  88                         // Get the latest revision ID from the master
  89                         $dbw = wfGetDB( DB_MASTER );
  90                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  91                         if ( $latest === false ) {
  92                                 return null; // page does not exist
  93                         }
  94                         $conds['rev_id'] = $latest;
  95                 } else {
  96                         // Use a join to get the latest revision
  97                         $conds[] = 'rev_id=page_latest';
  98                 }
  99                 return Revision::newFromConds( $conds );
 100         }
 101
 102         /**
 103          * Load either the current, or a specified, revision
 104          * that's attached to a given page ID.
 105          * Returns null if no such revision can be found.
 106          *
 107          * @param $revId Integer
 108          * @param $pageId Integer (optional)
 109          * @return Revision or null
 110          */
 111         public static function newFromPageId( $pageId, $revId = 0 ) {
 112                 $conds = array( 'page_id' => $pageId );
 113                 if ( $revId ) {
 114                         $conds['rev_id'] = $revId;
 115                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
 116                         // Get the latest revision ID from the master
 117                         $dbw = wfGetDB( DB_MASTER );
 118                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
 119                         if ( $latest === false ) {
 120                                 return null; // page does not exist
 121                         }
 122                         $conds['rev_id'] = $latest;
 123                 } else {
 124                         $conds[] = 'rev_id = page_latest';
 125                 }
 126                 return Revision::newFromConds( $conds );
 127         }
 128
 129         /**
 130          * Make a fake revision object from an archive table row. This is queried
 131          * for permissions or even inserted (as in Special:Undelete)
 132          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 133          *
 134          * @param $row
 135          * @param $overrides array
 136          *
 137          * @return Revision
 138          */
 139         public static function newFromArchiveRow( $row, $overrides = array() ) {
 140                 global $wgContentHandlerUseDB;
 141
 142                 $attribs = $overrides + array(
 143                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 144                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 145                         'comment'    => $row->ar_comment,
 146                         'user'       => $row->ar_user,
 147                         'user_text'  => $row->ar_user_text,
 148                         'timestamp'  => $row->ar_timestamp,
 149                         'minor_edit' => $row->ar_minor_edit,
 150                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 151                         'deleted'    => $row->ar_deleted,
 152                         'len'        => $row->ar_len,
 153                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 154                         'content_model' => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 155                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 156                 );
 157
 158                 if ( !$wgContentHandlerUseDB ) {
 159                         unset( $attribs['content_model'] );
 160                         unset( $attribs['content_format'] );
 161                 }
 162
 163                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 164                         // Pre-1.5 ar_text row
 165                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 166                         if ( $attribs['text'] === false ) {
 167                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 168                         }
 169                 }
 170                 return new self( $attribs );
 171         }
 172
 173         /**
 174          * @since 1.19
 175          *
 176          * @param $row
 177          * @return Revision
 178          */
 179         public static function newFromRow( $row ) {
 180                 return new self( $row );
 181         }
 182
 183         /**
 184          * Load a page revision from a given revision ID number.
 185          * Returns null if no such revision can be found.
 186          *
 187          * @param $db DatabaseBase
 188          * @param $id Integer
 189          * @return Revision or null
 190          */
 191         public static function loadFromId( $db, $id ) {
 192                 return Revision::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 193         }
 194
 195         /**
 196          * Load either the current, or a specified, revision
 197          * that's attached to a given page. If not attached
 198          * to that page, will return null.
 199          *
 200          * @param $db DatabaseBase
 201          * @param $pageid Integer
 202          * @param $id Integer
 203          * @return Revision or null
 204          */
 205         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 206                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 207                 if( $id ) {
 208                         $conds['rev_id'] = intval( $id );
 209                 } else {
 210                         $conds[] = 'rev_id=page_latest';
 211                 }
 212                 return Revision::loadFromConds( $db, $conds );
 213         }
 214
 215         /**
 216          * Load either the current, or a specified, revision
 217          * that's attached to a given page. If not attached
 218          * to that page, will return null.
 219          *
 220          * @param $db DatabaseBase
 221          * @param $title Title
 222          * @param $id Integer
 223          * @return Revision or null
 224          */
 225         public static function loadFromTitle( $db, $title, $id = 0 ) {
 226                 if( $id ) {
 227                         $matchId = intval( $id );
 228                 } else {
 229                         $matchId = 'page_latest';
 230                 }
 231                 return Revision::loadFromConds( $db,
 232                         array( "rev_id=$matchId",
 233                                    'page_namespace' => $title->getNamespace(),
 234                                    'page_title'     => $title->getDBkey() )
 235                 );
 236         }
 237
 238         /**
 239          * Load the revision for the given title with the given timestamp.
 240          * WARNING: Timestamps may in some circumstances not be unique,
 241          * so this isn't the best key to use.
 242          *
 243          * @param $db DatabaseBase
 244          * @param $title Title
 245          * @param $timestamp String
 246          * @return Revision or null
 247          */
 248         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 249                 return Revision::loadFromConds( $db,
 250                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 251                                    'page_namespace' => $title->getNamespace(),
 252                                    'page_title'     => $title->getDBkey() )
 253                 );
 254         }
 255
 256         /**
 257          * Given a set of conditions, fetch a revision.
 258          *
 259          * @param $conditions Array
 260          * @return Revision or null
 261          */
 262         public static function newFromConds( $conditions ) {
 263                 $db = wfGetDB( DB_SLAVE );
 264                 $rev = Revision::loadFromConds( $db, $conditions );
 265                 if( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 266                         $dbw = wfGetDB( DB_MASTER );
 267                         $rev = Revision::loadFromConds( $dbw, $conditions );
 268                 }
 269                 return $rev;
 270         }
 271
 272         /**
 273          * Given a set of conditions, fetch a revision from
 274          * the given database connection.
 275          *
 276          * @param $db DatabaseBase
 277          * @param $conditions Array
 278          * @return Revision or null
 279          */
 280         private static function loadFromConds( $db, $conditions ) {
 281                 $res = Revision::fetchFromConds( $db, $conditions );
 282                 if( $res ) {
 283                         $row = $res->fetchObject();
 284                         if( $row ) {
 285                                 $ret = new Revision( $row );
 286                                 return $ret;
 287                         }
 288                 }
 289                 $ret = null;
 290                 return $ret;
 291         }
 292
 293         /**
 294          * Return a wrapper for a series of database rows to
 295          * fetch all of a given page's revisions in turn.
 296          * Each row can be fed to the constructor to get objects.
 297          *
 298          * @param $title Title
 299          * @return ResultWrapper
 300          */
 301         public static function fetchRevision( $title ) {
 302                 return Revision::fetchFromConds(
 303                         wfGetDB( DB_SLAVE ),
 304                         array( 'rev_id=page_latest',
 305                                    'page_namespace' => $title->getNamespace(),
 306                                    'page_title'     => $title->getDBkey() )
 307                 );
 308         }
 309
 310         /**
 311          * Given a set of conditions, return a ResultWrapper
 312          * which will return matching database rows with the
 313          * fields necessary to build Revision objects.
 314          *
 315          * @param $db DatabaseBase
 316          * @param $conditions Array
 317          * @return ResultWrapper
 318          */
 319         private static function fetchFromConds( $db, $conditions ) {
 320                 $fields = array_merge(
 321                         self::selectFields(),
 322                         self::selectPageFields(),
 323                         self::selectUserFields()
 324                 );
 325                 return $db->select(
 326                         array( 'revision', 'page', 'user' ),
 327                         $fields,
 328                         $conditions,
 329                         __METHOD__,
 330                         array( 'LIMIT' => 1 ),
 331                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 332                 );
 333         }
 334
 335         /**
 336          * Return the value of a select() JOIN conds array for the user table.
 337          * This will get user table rows for logged-in users.
 338          * @since 1.19
 339          * @return Array
 340          */
 341         public static function userJoinCond() {
 342                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 343         }
 344
 345         /**
 346          * Return the value of a select() page conds array for the paeg table.
 347          * This will assure that the revision(s) are not orphaned from live pages.
 348          * @since 1.19
 349          * @return Array
 350          */
 351         public static function pageJoinCond() {
 352                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 353         }
 354
 355         /**
 356          * Return the list of revision fields that should be selected to create
 357          * a new revision.
 358          * @return array
 359          */
 360         public static function selectFields() {
 361                 global $wgContentHandlerUseDB;
 362
 363                 $fields = array(
 364                         'rev_id',
 365                         'rev_page',
 366                         'rev_text_id',
 367                         'rev_timestamp',
 368                         'rev_comment',
 369                         'rev_user_text',
 370                         'rev_user',
 371                         'rev_minor_edit',
 372                         'rev_deleted',
 373                         'rev_len',
 374                         'rev_parent_id',
 375                         'rev_sha1',
 376                 );
 377
 378                 if ( $wgContentHandlerUseDB ) {
 379                         $fields[] = 'rev_content_format';
 380                         $fields[] = 'rev_content_model';
 381                 }
 382
 383                 return $fields;
 384         }
 385
 386         /**
 387          * Return the list of text fields that should be selected to read the
 388          * revision text
 389          * @return array
 390          */
 391         public static function selectTextFields() {
 392                 return array(
 393                         'old_text',
 394                         'old_flags'
 395                 );
 396         }
 397
 398         /**
 399          * Return the list of page fields that should be selected from page table
 400          * @return array
 401          */
 402         public static function selectPageFields() {
 403                 return array(
 404                         'page_namespace',
 405                         'page_title',
 406                         'page_id',
 407                         'page_latest',
 408                         'page_is_redirect',
 409                         'page_len',
 410                 );
 411         }
 412
 413         /**
 414          * Return the list of user fields that should be selected from user table
 415          * @return array
 416          */
 417         public static function selectUserFields() {
 418                 return array( 'user_name' );
 419         }
 420
 421         /**
 422          * Constructor
 423          *
 424          * @param $row Mixed: either a database row or an array
 425          * @access private
 426          */
 427         function __construct( $row ) {
 428                 if( is_object( $row ) ) {
 429                         $this->mId        = intval( $row->rev_id );
 430                         $this->mPage      = intval( $row->rev_page );
 431                         $this->mTextId    = intval( $row->rev_text_id );
 432                         $this->mComment   =         $row->rev_comment;
 433                         $this->mUser      = intval( $row->rev_user );
 434                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 435                         $this->mTimestamp =         $row->rev_timestamp;
 436                         $this->mDeleted   = intval( $row->rev_deleted );
 437
 438                         if( !isset( $row->rev_parent_id ) ) {
 439                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 440                         } else {
 441                                 $this->mParentId  = intval( $row->rev_parent_id );
 442                         }
 443
 444                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 445                                 $this->mSize = null;
 446                         } else {
 447                                 $this->mSize = intval( $row->rev_len );
 448                         }
 449
 450                         if ( !isset( $row->rev_sha1 ) ) {
 451                                 $this->mSha1 = null;
 452                         } else {
 453                                 $this->mSha1 = $row->rev_sha1;
 454                         }
 455
 456                         if( isset( $row->page_latest ) ) {
 457                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 458                                 $this->mTitle = Title::newFromRow( $row );
 459                         } else {
 460                                 $this->mCurrent = false;
 461                                 $this->mTitle = null;
 462                         }
 463
 464                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 465                                 $this->mContentModel = null; # determine on demand if needed
 466                         } else {
 467                                 $this->mContentModel = intval( $row->rev_content_model );
 468                         }
 469
 470                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 471                                 $this->mContentFormat = null; # determine on demand if needed
 472                         } else {
 473                                 $this->mContentFormat = intval( $row->rev_content_format );
 474                         }
 475
 476                         // Lazy extraction...
 477                         $this->mText      = null;
 478                         if( isset( $row->old_text ) ) {
 479                                 $this->mTextRow = $row;
 480                         } else {
 481                                 // 'text' table row entry will be lazy-loaded
 482                                 $this->mTextRow = null;
 483                         }
 484
 485                         // Use user_name for users and rev_user_text for IPs...
 486                         $this->mUserText = null; // lazy load if left null
 487                         if ( $this->mUser == 0 ) {
 488                                 $this->mUserText = $row->rev_user_text; // IP user
 489                         } elseif ( isset( $row->user_name ) ) {
 490                                 $this->mUserText = $row->user_name; // logged-in user
 491                         }
 492                         $this->mOrigUserText = $row->rev_user_text;
 493                 } elseif( is_array( $row ) ) {
 494                         // Build a new revision to be saved...
 495                         global $wgUser; // ugh
 496
 497
 498                         # if we have a content object, use it to set the model and type
 499                         if ( !empty( $row['content'] ) ) {
 500                                 if ( !empty( $row['text_id'] ) ) { //@todo: when is that set? test with external store setup! check out insertOn() [dk]
 501                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), can't serialize content object" );
 502                                 }
 503
 504                                 $row['content_model'] = $row['content']->getModel();
 505                                 # note: mContentFormat is initializes later accordingly
 506                                 # note: content is serialized later in this method!
 507                                 # also set text to null?
 508                         }
 509
 510                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 511                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 512                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 513                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 514                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 515                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 516                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 517                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 518                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 519                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 520                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 521
 522                         $this->mContentModel = isset( $row['content_model']  )  ? intval( $row['content_model'] )  : null;
 523                         $this->mContentFormat    = isset( $row['content_format']  ) ? intval( $row['content_format'] ) : null;
 524
 525                         // Enforce spacing trimming on supplied text
 526                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 527                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 528                         $this->mTextRow   = null;
 529
 530                         # if we have a content object, override mText and mContentModel
 531                         if ( !empty( $row['content'] ) ) {
 532                                 $handler = $this->getContentHandler();
 533                                 $this->mContent = $row['content'];
 534
 535                                 $this->mContentModel = $this->mContent->getModel();
 536                                 $this->mContentHandler = null;
 537
 538                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 539                         } elseif ( !is_null( $this->mText ) ) {
 540                                 $handler = $this->getContentHandler();
 541                                 $this->mContent = $handler->unserializeContent( $this->mText );
 542                         }
 543
 544                         $this->mTitle     = null; # Load on demand if needed
 545                         $this->mCurrent   = false; # XXX: really? we are about to create a revision. it will usually then be the current one.
 546
 547                         # If we still have no length, see it we have the text to figure it out
 548                         if ( !$this->mSize ) {
 549                                 if ( !is_null( $this->mContent ) ) {
 550                                         $this->mSize = $this->mContent->getSize();
 551                                 } else {
 552                                         #XXX: my be inconsistent with the notion of "size" use for the present content model
 553                                         #NOTE: should never happen if we have either text or content object!
 554                                         $this->mSize = is_null( $this->mText ) ? null : strlen( $this->mText );
 555                                 }
 556                         }
 557
 558                         # Same for sha1
 559                         if ( $this->mSha1 === null ) {
 560                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 561                         }
 562
 563                         $this->getContentModel(); # force lazy init
 564                         $this->getContentFormat();    # force lazy init
 565                 } else {
 566                         throw new MWException( 'Revision constructor passed invalid row format.' );
 567                 }
 568                 $this->mUnpatrolled = null;
 569         }
 570
 571         /**
 572          * Get revision ID
 573          *
 574          * @return Integer|null
 575          */
 576         public function getId() {
 577                 return $this->mId;
 578         }
 579
 580         /**
 581          * Set the revision ID
 582          *
 583          * @since 1.19
 584          * @param $id Integer
 585          */
 586         public function setId( $id ) {
 587                 $this->mId = $id;
 588         }
 589
 590         /**
 591          * Get text row ID
 592          *
 593          * @return Integer|null
 594          */
 595         public function getTextId() {
 596                 return $this->mTextId;
 597         }
 598
 599         /**
 600          * Get parent revision ID (the original previous page revision)
 601          *
 602          * @return Integer|null
 603          */
 604         public function getParentId() {
 605                 return $this->mParentId;
 606         }
 607
 608         /**
 609          * Returns the length of the text in this revision, or null if unknown.
 610          *
 611          * @return Integer|null
 612          */
 613         public function getSize() {
 614                 return $this->mSize;
 615         }
 616
 617         /**
 618          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 619          *
 620          * @return String|null
 621          */
 622         public function getSha1() {
 623                 return $this->mSha1;
 624         }
 625
 626         /**
 627          * Returns the title of the page associated with this entry or null.
 628          *
 629          * Will do a query, when title is not set and id is given.
 630          *
 631          * @return Title|null
 632          */
 633         public function getTitle() {
 634                 if( isset( $this->mTitle ) ) {
 635                         return $this->mTitle;
 636                 }
 637                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL
 638                         $dbr = wfGetDB( DB_SLAVE );
 639                         $row = $dbr->selectRow(
 640                                 array( 'page', 'revision' ),
 641                                 self::selectPageFields(),
 642                                 array( 'page_id=rev_page',
 643                                            'rev_id' => $this->mId ),
 644                                 __METHOD__ );
 645                         if ( $row ) {
 646                                 $this->mTitle = Title::newFromRow( $row );
 647                         }
 648                 }
 649                 return $this->mTitle;
 650         }
 651
 652         /**
 653          * Set the title of the revision
 654          *
 655          * @param $title Title
 656          */
 657         public function setTitle( $title ) {
 658                 $this->mTitle = $title;
 659         }
 660
 661         /**
 662          * Get the page ID
 663          *
 664          * @return Integer|null
 665          */
 666         public function getPage() {
 667                 return $this->mPage;
 668         }
 669
 670         /**
 671          * Fetch revision's user id if it's available to the specified audience.
 672          * If the specified audience does not have access to it, zero will be
 673          * returned.
 674          *
 675          * @param $audience Integer: one of:
 676          *      Revision::FOR_PUBLIC       to be displayed to all users
 677          *      Revision::FOR_THIS_USER    to be displayed to the given user
 678          *      Revision::RAW              get the ID regardless of permissions
 679          * @param $user User object to check for, only if FOR_THIS_USER is passed
 680          *              to the $audience parameter
 681          * @return Integer
 682          */
 683         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 684                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 685                         return 0;
 686                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 687                         return 0;
 688                 } else {
 689                         return $this->mUser;
 690                 }
 691         }
 692
 693         /**
 694          * Fetch revision's user id without regard for the current user's permissions
 695          *
 696          * @return String
 697          */
 698         public function getRawUser() {
 699                 return $this->mUser;
 700         }
 701
 702         /**
 703          * Fetch revision's username if it's available to the specified audience.
 704          * If the specified audience does not have access to the username, an
 705          * empty string will be returned.
 706          *
 707          * @param $audience Integer: one of:
 708          *      Revision::FOR_PUBLIC       to be displayed to all users
 709          *      Revision::FOR_THIS_USER    to be displayed to the given user
 710          *      Revision::RAW              get the text regardless of permissions
 711          * @param $user User object to check for, only if FOR_THIS_USER is passed
 712          *              to the $audience parameter
 713          * @return string
 714          */
 715         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 716                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 717                         return '';
 718                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 719                         return '';
 720                 } else {
 721                         return $this->getRawUserText();
 722                 }
 723         }
 724
 725         /**
 726          * Fetch revision's username without regard for view restrictions
 727          *
 728          * @return String
 729          */
 730         public function getRawUserText() {
 731                 if ( $this->mUserText === null ) {
 732                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 733                         if ( $this->mUserText === false ) {
 734                                 # This shouldn't happen, but it can if the wiki was recovered
 735                                 # via importing revs and there is no user table entry yet.
 736                                 $this->mUserText = $this->mOrigUserText;
 737                         }
 738                 }
 739                 return $this->mUserText;
 740         }
 741
 742         /**
 743          * Fetch revision comment if it's available to the specified audience.
 744          * If the specified audience does not have access to the comment, an
 745          * empty string will be 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 text 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 String
 754          */
 755         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 756                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 757                         return '';
 758                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 759                         return '';
 760                 } else {
 761                         return $this->mComment;
 762                 }
 763         }
 764
 765         /**
 766          * Fetch revision comment without regard for the current user's permissions
 767          *
 768          * @return String
 769          */
 770         public function getRawComment() {
 771                 return $this->mComment;
 772         }
 773
 774         /**
 775          * @return Boolean
 776          */
 777         public function isMinor() {
 778                 return (bool)$this->mMinorEdit;
 779         }
 780
 781         /**
 782          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 783          */
 784         public function isUnpatrolled() {
 785                 if( $this->mUnpatrolled !== null ) {
 786                         return $this->mUnpatrolled;
 787                 }
 788                 $dbr = wfGetDB( DB_SLAVE );
 789                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 790                         'rc_id',
 791                         array( // Add redundant user,timestamp condition so we can use the existing index
 792                                 'rc_user_text'  => $this->getRawUserText(),
 793                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 794                                 'rc_this_oldid' => $this->getId(),
 795                                 'rc_patrolled'  => 0
 796                         ),
 797                         __METHOD__
 798                 );
 799                 return (int)$this->mUnpatrolled;
 800         }
 801
 802         /**
 803          * @param $field int one of DELETED_* bitfield constants
 804          *
 805          * @return Boolean
 806          */
 807         public function isDeleted( $field ) {
 808                 return ( $this->mDeleted & $field ) == $field;
 809         }
 810
 811         /**
 812          * Get the deletion bitfield of the revision
 813          *
 814          * @return int
 815          */
 816         public function getVisibility() {
 817                 return (int)$this->mDeleted;
 818         }
 819
 820         /**
 821          * Fetch revision text if it's available to the specified audience.
 822          * If the specified audience does not have the ability to view this
 823          * revision, an empty string will be returned.
 824          *
 825          * @param $audience Integer: one of:
 826          *      Revision::FOR_PUBLIC       to be displayed to all users
 827          *      Revision::FOR_THIS_USER    to be displayed to the given user
 828          *      Revision::RAW              get the text regardless of permissions
 829          * @param $user User object to check for, only if FOR_THIS_USER is passed
 830          *              to the $audience parameter
 831          * @return String
 832          * @deprecated in 1.WD, use getContent() instead
 833          */
 834         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) { #FIXME: deprecated, replace usage! #FIXME: used a LOT!
 835                 wfDeprecated( __METHOD__, '1.WD' );
 836
 837                 $content = $this->getContent( $audience, $user );
 838                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 839         }
 840
 841         /**
 842          * Fetch revision content if it's available to the specified audience.
 843          * If the specified audience does not have the ability to view this
 844          * revision, null will be returned.
 845          *
 846          * @param $audience Integer: one of:
 847          *      Revision::FOR_PUBLIC       to be displayed to all users
 848          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 849          *      Revision::RAW              get the text regardless of permissions
 850          * @param $user User object to check for, only if FOR_THIS_USER is passed
 851          *              to the $audience parameter
 852          * @return Content
 853          *
 854          * @since 1.WD
 855          */
 856         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 857                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 858                         return null;
 859                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 860                         return null;
 861                 } else {
 862                         return $this->getContentInternal();
 863                 }
 864         }
 865
 866         /**
 867          * Alias for getText(Revision::FOR_THIS_USER)
 868          *
 869          * @deprecated since 1.17
 870          * @return String
 871          */
 872         public function revText() {
 873                 wfDeprecated( __METHOD__, '1.17' );
 874                 return $this->getText( self::FOR_THIS_USER );
 875         }
 876
 877         /**
 878          * Fetch revision text without regard for view restrictions
 879          *
 880          * @return String
 881          *
 882          * @deprecated since 1.WD. Instead, use Revision::getContent( Revision::RAW ) or Revision::getSerializedData() as appropriate.
 883          */
 884         public function getRawText() { #FIXME: deprecated, replace usage!
 885                 wfDeprecated( __METHOD__, "1.WD" );
 886
 887                 return $this->getText( self::RAW );
 888         }
 889
 890         /**
 891          * Fetch original serialized data without regard for view restrictions
 892          *
 893          * @return String
 894          *
 895          * @since 1.WD
 896          */
 897         public function getSerializedData() {
 898                 return $this->mText;
 899         }
 900
 901         protected function getContentInternal() {
 902                 if( is_null( $this->mContent ) ) {
 903                         // Revision is immutable. Load on demand:
 904
 905                         $handler = $this->getContentHandler();
 906                         $format = $this->getContentFormat();
 907                         $title = $this->getTitle();
 908
 909                         if( is_null( $this->mText ) ) {
 910                                 // Load text on demand:
 911                                 $this->mText = $this->loadText();
 912                         }
 913
 914                         $this->mContent = is_null( $this->mText ) ? null : $handler->unserializeContent( $this->mText, $format );
 915                 }
 916
 917                 return $this->mContent;
 918         }
 919
 920         /**
 921          * Returns the content model for this revision.
 922          *
 923          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
 924          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
 925          * is used as a last resort.
 926          *
 927          * @return int the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
 928          **/
 929         public function getContentModel() {
 930                 if ( !$this->mContentModel ) {
 931                         $title = $this->getTitle();
 932                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
 933
 934                         assert( !empty( $this->mContentModel ) );
 935                 }
 936
 937                 return $this->mContentModel;
 938         }
 939
 940         /**
 941          * Returns the content format for this revision.
 942          *
 943          * If no content format was stored in the database, the default format for this
 944          * revision's content model is returned.
 945          *
 946          * @return int the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
 947          **/
 948         public function getContentFormat() {
 949                 if ( !$this->mContentFormat ) {
 950                         $handler = $this->getContentHandler();
 951                         $this->mContentFormat = $handler->getDefaultFormat();
 952
 953                         assert( !empty( $this->mContentFormat ) );
 954                 }
 955
 956                 return $this->mContentFormat;
 957         }
 958
 959         /**
 960          * Returns the content handler appropriate for this revision's content model.
 961          *
 962          * @return ContentHandler
 963          */
 964         public function getContentHandler() {
 965                 if ( !$this->mContentHandler ) {
 966                         $model = $this->getContentModel();
 967                         $this->mContentHandler = ContentHandler::getForModelID( $model );
 968
 969                         $format = $this->getContentFormat();
 970
 971                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
 972                                 $formatName = ContentHandler::getContentFormatMimeType( $format );
 973                                 $modelName = ContentHandler::getContentModelName( $model );
 974
 975                                 throw new MWException( "Oops, the content format #$format ($formatName) is not supported for this content model, #$model ($modelName)" );
 976                         }
 977                 }
 978
 979                 return $this->mContentHandler;
 980         }
 981
 982         /**
 983          * @return String
 984          */
 985         public function getTimestamp() {
 986                 return wfTimestamp( TS_MW, $this->mTimestamp );
 987         }
 988
 989         /**
 990          * @return Boolean
 991          */
 992         public function isCurrent() {
 993                 return $this->mCurrent;
 994         }
 995
 996         /**
 997          * Get previous revision for this title
 998          *
 999          * @return Revision or null
1000          */
1001         public function getPrevious() {
1002                 if( $this->getTitle() ) {
1003                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1004                         if( $prev ) {
1005                                 return Revision::newFromTitle( $this->getTitle(), $prev );
1006                         }
1007                 }
1008                 return null;
1009         }
1010
1011         /**
1012          * Get next revision for this title
1013          *
1014          * @return Revision or null
1015          */
1016         public function getNext() {
1017                 if( $this->getTitle() ) {
1018                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1019                         if ( $next ) {
1020                                 return Revision::newFromTitle( $this->getTitle(), $next );
1021                         }
1022                 }
1023                 return null;
1024         }
1025
1026         /**
1027          * Get previous revision Id for this page_id
1028          * This is used to populate rev_parent_id on save
1029          *
1030          * @param $db DatabaseBase
1031          * @return Integer
1032          */
1033         private function getPreviousRevisionId( $db ) {
1034                 if( is_null( $this->mPage ) ) {
1035                         return 0;
1036                 }
1037                 # Use page_latest if ID is not given
1038                 if( !$this->mId ) {
1039                         $prevId = $db->selectField( 'page', 'page_latest',
1040                                 array( 'page_id' => $this->mPage ),
1041                                 __METHOD__ );
1042                 } else {
1043                         $prevId = $db->selectField( 'revision', 'rev_id',
1044                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1045                                 __METHOD__,
1046                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1047                 }
1048                 return intval( $prevId );
1049         }
1050
1051         /**
1052           * Get revision text associated with an old or archive row
1053           * $row is usually an object from wfFetchRow(), both the flags and the text
1054           * field must be included
1055           *
1056           * @param $row Object: the text data
1057           * @param $prefix String: table prefix (default 'old_')
1058           * @return String: text the text requested or false on failure
1059           */
1060         public static function getRevisionText( $row, $prefix = 'old_' ) {
1061                 wfProfileIn( __METHOD__ );
1062
1063                 # Get data
1064                 $textField = $prefix . 'text';
1065                 $flagsField = $prefix . 'flags';
1066
1067                 if( isset( $row->$flagsField ) ) {
1068                         $flags = explode( ',', $row->$flagsField );
1069                 } else {
1070                         $flags = array();
1071                 }
1072
1073                 if( isset( $row->$textField ) ) {
1074                         $text = $row->$textField;
1075                 } else {
1076                         wfProfileOut( __METHOD__ );
1077                         return false;
1078                 }
1079
1080                 # Use external methods for external objects, text in table is URL-only then
1081                 if ( in_array( 'external', $flags ) ) {
1082                         $url = $text;
1083                         $parts = explode( '://', $url, 2 );
1084                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1085                                 wfProfileOut( __METHOD__ );
1086                                 return false;
1087                         }
1088                         $text = ExternalStore::fetchFromURL( $url );
1089                 }
1090
1091                 // If the text was fetched without an error, convert it
1092                 if ( $text !== false ) {
1093                         if( in_array( 'gzip', $flags ) ) {
1094                                 # Deal with optional compression of archived pages.
1095                                 # This can be done periodically via maintenance/compressOld.php, and
1096                                 # as pages are saved if $wgCompressRevisions is set.
1097                                 $text = gzinflate( $text );
1098                         }
1099
1100                         if( in_array( 'object', $flags ) ) {
1101                                 # Generic compressed storage
1102                                 $obj = unserialize( $text );
1103                                 if ( !is_object( $obj ) ) {
1104                                         // Invalid object
1105                                         wfProfileOut( __METHOD__ );
1106                                         return false;
1107                                 }
1108                                 $text = $obj->getText();
1109                         }
1110
1111                         global $wgLegacyEncoding;
1112                         if( $text !== false && $wgLegacyEncoding
1113                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1114                         {
1115                                 # Old revisions kept around in a legacy encoding?
1116                                 # Upconvert on demand.
1117                                 # ("utf8" checked for compatibility with some broken
1118                                 #  conversion scripts 2008-12-30)
1119                                 global $wgContLang;
1120                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1121                         }
1122                 }
1123                 wfProfileOut( __METHOD__ );
1124                 return $text;
1125         }
1126
1127         /**
1128          * If $wgCompressRevisions is enabled, we will compress data.
1129          * The input string is modified in place.
1130          * Return value is the flags field: contains 'gzip' if the
1131          * data is compressed, and 'utf-8' if we're saving in UTF-8
1132          * mode.
1133          *
1134          * @param $text Mixed: reference to a text
1135          * @return String
1136          */
1137         public static function compressRevisionText( &$text ) {
1138                 global $wgCompressRevisions;
1139                 $flags = array();
1140
1141                 # Revisions not marked this way will be converted
1142                 # on load if $wgLegacyCharset is set in the future.
1143                 $flags[] = 'utf-8';
1144
1145                 if( $wgCompressRevisions ) {
1146                         if( function_exists( 'gzdeflate' ) ) {
1147                                 $text = gzdeflate( $text );
1148                                 $flags[] = 'gzip';
1149                         } else {
1150                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
1151                         }
1152                 }
1153                 return implode( ',', $flags );
1154         }
1155
1156         /**
1157          * Insert a new revision into the database, returning the new revision ID
1158          * number on success and dies horribly on failure.
1159          *
1160          * @param $dbw DatabaseBase: (master connection)
1161          * @return Integer
1162          */
1163         public function insertOn( $dbw ) {
1164                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1165
1166                 wfProfileIn( __METHOD__ );
1167
1168                 $data = $this->mText;
1169                 $flags = Revision::compressRevisionText( $data );
1170
1171                 # Write to external storage if required
1172                 if( $wgDefaultExternalStore ) {
1173                         // Store and get the URL
1174                         $data = ExternalStore::insertToDefault( $data );
1175                         if( !$data ) {
1176                                 throw new MWException( "Unable to store text to external storage" );
1177                         }
1178                         if( $flags ) {
1179                                 $flags .= ',';
1180                         }
1181                         $flags .= 'external';
1182                 }
1183
1184                 # Record the text (or external storage URL) to the text table
1185                 if( !isset( $this->mTextId ) ) {
1186                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1187                         $dbw->insert( 'text',
1188                                 array(
1189                                         'old_id'    => $old_id,
1190                                         'old_text'  => $data,
1191                                         'old_flags' => $flags,
1192                                 ), __METHOD__
1193                         );
1194                         $this->mTextId = $dbw->insertId();
1195                 }
1196
1197                 if ( $this->mComment === null ) $this->mComment = "";
1198
1199                 # Record the edit in revisions
1200                 $rev_id = isset( $this->mId )
1201                         ? $this->mId
1202                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1203
1204                 $row = array(
1205                         'rev_id'         => $rev_id,
1206                         'rev_page'       => $this->mPage,
1207                         'rev_text_id'    => $this->mTextId,
1208                         'rev_comment'    => $this->mComment,
1209                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1210                         'rev_user'       => $this->mUser,
1211                         'rev_user_text'  => $this->mUserText,
1212                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1213                         'rev_deleted'    => $this->mDeleted,
1214                         'rev_len'        => $this->mSize,
1215                         'rev_parent_id'  => is_null( $this->mParentId )
1216                                 ? $this->getPreviousRevisionId( $dbw )
1217                                 : $this->mParentId,
1218                         'rev_sha1'       => is_null( $this->mSha1 )
1219                                 ? Revision::base36Sha1( $this->mText )
1220                                 : $this->mSha1,
1221                 );
1222
1223                 if ( $wgContentHandlerUseDB ) {
1224                         $row[ 'rev_content_model' ] = $this->getContentModel();
1225                         $row[ 'rev_content_format' ] = $this->getContentFormat();
1226                 }
1227
1228                 $dbw->insert( 'revision', $row, __METHOD__ );
1229
1230                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1231
1232                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1233
1234                 wfProfileOut( __METHOD__ );
1235                 return $this->mId;
1236         }
1237
1238         /**
1239          * Get the base 36 SHA-1 value for a string of text
1240          * @param $text String
1241          * @return String
1242          */
1243         public static function base36Sha1( $text ) {
1244                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1245         }
1246
1247         /**
1248          * Lazy-load the revision's text.
1249          * Currently hardcoded to the 'text' table storage engine.
1250          *
1251          * @return String
1252          */
1253         protected function loadText() {
1254                 wfProfileIn( __METHOD__ );
1255
1256                 // Caching may be beneficial for massive use of external storage
1257                 global $wgRevisionCacheExpiry, $wgMemc;
1258                 $textId = $this->getTextId();
1259                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1260                 if( $wgRevisionCacheExpiry ) {
1261                         $text = $wgMemc->get( $key );
1262                         if( is_string( $text ) ) {
1263                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1264                                 wfProfileOut( __METHOD__ );
1265                                 return $text;
1266                         }
1267                 }
1268
1269                 // If we kept data for lazy extraction, use it now...
1270                 if ( isset( $this->mTextRow ) ) {
1271                         $row = $this->mTextRow;
1272                         $this->mTextRow = null;
1273                 } else {
1274                         $row = null;
1275                 }
1276
1277                 if( !$row ) {
1278                         // Text data is immutable; check slaves first.
1279                         $dbr = wfGetDB( DB_SLAVE );
1280                         $row = $dbr->selectRow( 'text',
1281                                 array( 'old_text', 'old_flags' ),
1282                                 array( 'old_id' => $this->getTextId() ),
1283                                 __METHOD__ );
1284                 }
1285
1286                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1287                         // Possible slave lag!
1288                         $dbw = wfGetDB( DB_MASTER );
1289                         $row = $dbw->selectRow( 'text',
1290                                 array( 'old_text', 'old_flags' ),
1291                                 array( 'old_id' => $this->getTextId() ),
1292                                 __METHOD__ );
1293                 }
1294
1295                 $text = self::getRevisionText( $row );
1296
1297                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1298                 if( $wgRevisionCacheExpiry && $text !== false ) {
1299                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1300                 }
1301
1302                 wfProfileOut( __METHOD__ );
1303
1304                 return $text;
1305         }
1306
1307         /**
1308          * Create a new null-revision for insertion into a page's
1309          * history. This will not re-save the text, but simply refer
1310          * to the text from the previous version.
1311          *
1312          * Such revisions can for instance identify page rename
1313          * operations and other such meta-modifications.
1314          *
1315          * @param $dbw DatabaseBase
1316          * @param $pageId Integer: ID number of the page to read from
1317          * @param $summary String: revision's summary
1318          * @param $minor Boolean: whether the revision should be considered as minor
1319          * @return Revision|null on error
1320          */
1321         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1322                 global $wgContentHandlerUseDB;
1323
1324                 wfProfileIn( __METHOD__ );
1325
1326                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1327                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1328
1329                 if ( $wgContentHandlerUseDB ) {
1330                         $fields[] = 'rev_content_model';
1331                         $fields[] = 'rev_content_format';
1332                 }
1333
1334                 $current = $dbw->selectRow(
1335                         array( 'page', 'revision' ),
1336                         $fields,
1337                         array(
1338                                 'page_id' => $pageId,
1339                                 'page_latest=rev_id',
1340                                 ),
1341                         __METHOD__ );
1342
1343                 if( $current ) {
1344                         $row = array(
1345                                 'page'       => $pageId,
1346                                 'comment'    => $summary,
1347                                 'minor_edit' => $minor,
1348                                 'text_id'    => $current->rev_text_id,
1349                                 'parent_id'  => $current->page_latest,
1350                                 'len'        => $current->rev_len,
1351                                 'sha1'       => $current->rev_sha1
1352                         );
1353
1354                         if ( $wgContentHandlerUseDB ) {
1355                                 $row[ 'content_model' ] = $current->rev_content_model;
1356                                 $row[ 'content_format' ] = $current->rev_content_format;
1357                         }
1358
1359                         $revision = new Revision( $row );
1360                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1361                 } else {
1362                         $revision = null;
1363                 }
1364
1365                 wfProfileOut( __METHOD__ );
1366                 return $revision;
1367         }
1368
1369         /**
1370          * Determine if the current user is allowed to view a particular
1371          * field of this revision, if it's marked as deleted.
1372          *
1373          * @param $field Integer:one of self::DELETED_TEXT,
1374          *                              self::DELETED_COMMENT,
1375          *                              self::DELETED_USER
1376          * @param $user User object to check, or null to use $wgUser
1377          * @return Boolean
1378          */
1379         public function userCan( $field, User $user = null ) {
1380                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1381         }
1382
1383         /**
1384          * Determine if the current user is allowed to view a particular
1385          * field of this revision, if it's marked as deleted. This is used
1386          * by various classes to avoid duplication.
1387          *
1388          * @param $bitfield Integer: current field
1389          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1390          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1391          *                               self::DELETED_USER = File::DELETED_USER
1392          * @param $user User object to check, or null to use $wgUser
1393          * @return Boolean
1394          */
1395         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1396                 if( $bitfield & $field ) { // aspect is deleted
1397                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1398                                 $permission = 'suppressrevision';
1399                         } elseif ( $field & self::DELETED_TEXT ) {
1400                                 $permission = 'deletedtext';
1401                         } else {
1402                                 $permission = 'deletedhistory';
1403                         }
1404                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1405                         if ( $user === null ) {
1406                                 global $wgUser;
1407                                 $user = $wgUser;
1408                         }
1409                         return $user->isAllowed( $permission );
1410                 } else {
1411                         return true;
1412                 }
1413         }
1414
1415         /**
1416          * Get rev_timestamp from rev_id, without loading the rest of the row
1417          *
1418          * @param $title Title
1419          * @param $id Integer
1420          * @return String
1421          */
1422         static function getTimestampFromId( $title, $id ) {
1423                 $dbr = wfGetDB( DB_SLAVE );
1424                 // Casting fix for DB2
1425                 if ( $id == '' ) {
1426                         $id = 0;
1427                 }
1428                 $conds = array( 'rev_id' => $id );
1429                 $conds['rev_page'] = $title->getArticleID();
1430                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1431                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1432                         # Not in slave, try master
1433                         $dbw = wfGetDB( DB_MASTER );
1434                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1435                 }
1436                 return wfTimestamp( TS_MW, $timestamp );
1437         }
1438
1439         /**
1440          * Get count of revisions per page...not very efficient
1441          *
1442          * @param $db DatabaseBase
1443          * @param $id Integer: page id
1444          * @return Integer
1445          */
1446         static function countByPageId( $db, $id ) {
1447                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1448                         array( 'rev_page' => $id ), __METHOD__ );
1449                 if( $row ) {
1450                         return $row->revCount;
1451                 }
1452                 return 0;
1453         }
1454
1455         /**
1456          * Get count of revisions per page...not very efficient
1457          *
1458          * @param $db DatabaseBase
1459          * @param $title Title
1460          * @return Integer
1461          */
1462         static function countByTitle( $db, $title ) {
1463                 $id = $title->getArticleID();
1464                 if( $id ) {
1465                         return Revision::countByPageId( $db, $id );
1466                 }
1467                 return 0;
1468         }
1469 }