includes/Revision.php

   1 <?php
   2
   3 /**
   4  * @todo document
   5  */
   6 class Revision {
   7         protected $mId;
   8         protected $mPage;
   9         protected $mUserText;
  10         protected $mOrigUserText;
  11         protected $mUser;
  12         protected $mMinorEdit;
  13         protected $mTimestamp;
  14         protected $mDeleted;
  15         protected $mSize;
  16         protected $mSha1;
  17         protected $mParentId;
  18         protected $mComment;
  19         protected $mText;
  20         protected $mTextRow;
  21         protected $mTitle;
  22         protected $mCurrent;
  23         protected $mContentModel;
  24         protected $mContentFormat;
  25         protected $mContent;
  26         protected $mContentHandler;
  27
  28         const DELETED_TEXT = 1;
  29         const DELETED_COMMENT = 2;
  30         const DELETED_USER = 4;
  31         const DELETED_RESTRICTED = 8;
  32         // Convenience field
  33         const SUPPRESSED_USER = 12;
  34         // Audience options for Revision::getText()
  35         const FOR_PUBLIC = 1;
  36         const FOR_THIS_USER = 2;
  37         const RAW = 3;
  38
  39         /**
  40          * Load a page revision from a given revision ID number.
  41          * Returns null if no such revision can be found.
  42          *
  43          * @param $id Integer
  44          * @return Revision or null
  45          */
  46         public static function newFromId( $id ) {
  47                 return Revision::newFromConds( array( 'rev_id' => intval( $id ) ) );
  48         }
  49
  50         /**
  51          * Load either the current, or a specified, revision
  52          * that's attached to a given title. If not attached
  53          * to that title, will return null.
  54          *
  55          * @param $title Title
  56          * @param $id Integer (optional)
  57          * @return Revision or null
  58          */
  59         public static function newFromTitle( $title, $id = 0 ) {
  60                 $conds = array(
  61                         'page_namespace' => $title->getNamespace(),
  62                         'page_title'     => $title->getDBkey()
  63                 );
  64                 if ( $id ) {
  65                         // Use the specified ID
  66                         $conds['rev_id'] = $id;
  67                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  68                         // Get the latest revision ID from the master
  69                         $dbw = wfGetDB( DB_MASTER );
  70                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  71                         if ( $latest === false ) {
  72                                 return null; // page does not exist
  73                         }
  74                         $conds['rev_id'] = $latest;
  75                 } else {
  76                         // Use a join to get the latest revision
  77                         $conds[] = 'rev_id=page_latest';
  78                 }
  79                 return Revision::newFromConds( $conds );
  80         }
  81
  82         /**
  83          * Load either the current, or a specified, revision
  84          * that's attached to a given page ID.
  85          * Returns null if no such revision can be found.
  86          *
  87          * @param $revId Integer
  88          * @param $pageId Integer (optional)
  89          * @return Revision or null
  90          */
  91         public static function newFromPageId( $pageId, $revId = 0 ) {
  92                 $conds = array( 'page_id' => $pageId );
  93                 if ( $revId ) {
  94                         $conds['rev_id'] = $revId;
  95                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  96                         // Get the latest revision ID from the master
  97                         $dbw = wfGetDB( DB_MASTER );
  98                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  99                         if ( $latest === false ) {
 100                                 return null; // page does not exist
 101                         }
 102                         $conds['rev_id'] = $latest;
 103                 } else {
 104                         $conds[] = 'rev_id = page_latest';
 105                 }
 106                 return Revision::newFromConds( $conds );
 107         }
 108
 109         /**
 110          * Make a fake revision object from an archive table row. This is queried
 111          * for permissions or even inserted (as in Special:Undelete)
 112          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 113          *
 114          * @param $row
 115          * @param $overrides array
 116          *
 117          * @return Revision
 118          */
 119         public static function newFromArchiveRow( $row, $overrides = array() ) {
 120                 global $wgContentHandlerUseDB;
 121
 122                 $attribs = $overrides + array(
 123                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 124                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 125                         'comment'    => $row->ar_comment,
 126                         'user'       => $row->ar_user,
 127                         'user_text'  => $row->ar_user_text,
 128                         'timestamp'  => $row->ar_timestamp,
 129                         'minor_edit' => $row->ar_minor_edit,
 130                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 131                         'deleted'    => $row->ar_deleted,
 132                         'len'        => $row->ar_len,
 133                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 134                         'content_model' => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 135                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 136                 );
 137
 138                 if ( !$wgContentHandlerUseDB ) {
 139                         unset( $attribs['content_model'] );
 140                         unset( $attribs['content_format'] );
 141                 }
 142
 143                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 144                         // Pre-1.5 ar_text row
 145                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 146                         if ( $attribs['text'] === false ) {
 147                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 148                         }
 149                 }
 150                 return new self( $attribs );
 151         }
 152
 153         /**
 154          * @since 1.19
 155          *
 156          * @param $row
 157          * @return Revision
 158          */
 159         public static function newFromRow( $row ) {
 160                 return new self( $row );
 161         }
 162
 163         /**
 164          * Load a page revision from a given revision ID number.
 165          * Returns null if no such revision can be found.
 166          *
 167          * @param $db DatabaseBase
 168          * @param $id Integer
 169          * @return Revision or null
 170          */
 171         public static function loadFromId( $db, $id ) {
 172                 return Revision::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 173         }
 174
 175         /**
 176          * Load either the current, or a specified, revision
 177          * that's attached to a given page. If not attached
 178          * to that page, will return null.
 179          *
 180          * @param $db DatabaseBase
 181          * @param $pageid Integer
 182          * @param $id Integer
 183          * @return Revision or null
 184          */
 185         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 186                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 187                 if( $id ) {
 188                         $conds['rev_id'] = intval( $id );
 189                 } else {
 190                         $conds[] = 'rev_id=page_latest';
 191                 }
 192                 return Revision::loadFromConds( $db, $conds );
 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 $title Title
 202          * @param $id Integer
 203          * @return Revision or null
 204          */
 205         public static function loadFromTitle( $db, $title, $id = 0 ) {
 206                 if( $id ) {
 207                         $matchId = intval( $id );
 208                 } else {
 209                         $matchId = 'page_latest';
 210                 }
 211                 return Revision::loadFromConds( $db,
 212                         array( "rev_id=$matchId",
 213                                    'page_namespace' => $title->getNamespace(),
 214                                    'page_title'     => $title->getDBkey() )
 215                 );
 216         }
 217
 218         /**
 219          * Load the revision for the given title with the given timestamp.
 220          * WARNING: Timestamps may in some circumstances not be unique,
 221          * so this isn't the best key to use.
 222          *
 223          * @param $db DatabaseBase
 224          * @param $title Title
 225          * @param $timestamp String
 226          * @return Revision or null
 227          */
 228         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 229                 return Revision::loadFromConds( $db,
 230                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 231                                    'page_namespace' => $title->getNamespace(),
 232                                    'page_title'     => $title->getDBkey() )
 233                 );
 234         }
 235
 236         /**
 237          * Given a set of conditions, fetch a revision.
 238          *
 239          * @param $conditions Array
 240          * @return Revision or null
 241          */
 242         public static function newFromConds( $conditions ) {
 243                 $db = wfGetDB( DB_SLAVE );
 244                 $rev = Revision::loadFromConds( $db, $conditions );
 245                 if( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 246                         $dbw = wfGetDB( DB_MASTER );
 247                         $rev = Revision::loadFromConds( $dbw, $conditions );
 248                 }
 249                 return $rev;
 250         }
 251
 252         /**
 253          * Given a set of conditions, fetch a revision from
 254          * the given database connection.
 255          *
 256          * @param $db DatabaseBase
 257          * @param $conditions Array
 258          * @return Revision or null
 259          */
 260         private static function loadFromConds( $db, $conditions ) {
 261                 $res = Revision::fetchFromConds( $db, $conditions );
 262                 if( $res ) {
 263                         $row = $res->fetchObject();
 264                         if( $row ) {
 265                                 $ret = new Revision( $row );
 266                                 return $ret;
 267                         }
 268                 }
 269                 $ret = null;
 270                 return $ret;
 271         }
 272
 273         /**
 274          * Return a wrapper for a series of database rows to
 275          * fetch all of a given page's revisions in turn.
 276          * Each row can be fed to the constructor to get objects.
 277          *
 278          * @param $title Title
 279          * @return ResultWrapper
 280          */
 281         public static function fetchRevision( $title ) {
 282                 return Revision::fetchFromConds(
 283                         wfGetDB( DB_SLAVE ),
 284                         array( 'rev_id=page_latest',
 285                                    'page_namespace' => $title->getNamespace(),
 286                                    'page_title'     => $title->getDBkey() )
 287                 );
 288         }
 289
 290         /**
 291          * Given a set of conditions, return a ResultWrapper
 292          * which will return matching database rows with the
 293          * fields necessary to build Revision objects.
 294          *
 295          * @param $db DatabaseBase
 296          * @param $conditions Array
 297          * @return ResultWrapper
 298          */
 299         private static function fetchFromConds( $db, $conditions ) {
 300                 $fields = array_merge(
 301                         self::selectFields(),
 302                         self::selectPageFields(),
 303                         self::selectUserFields()
 304                 );
 305                 return $db->select(
 306                         array( 'revision', 'page', 'user' ),
 307                         $fields,
 308                         $conditions,
 309                         __METHOD__,
 310                         array( 'LIMIT' => 1 ),
 311                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 312                 );
 313         }
 314
 315         /**
 316          * Return the value of a select() JOIN conds array for the user table.
 317          * This will get user table rows for logged-in users.
 318          * @since 1.19
 319          * @return Array
 320          */
 321         public static function userJoinCond() {
 322                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 323         }
 324
 325         /**
 326          * Return the value of a select() page conds array for the paeg table.
 327          * This will assure that the revision(s) are not orphaned from live pages.
 328          * @since 1.19
 329          * @return Array
 330          */
 331         public static function pageJoinCond() {
 332                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 333         }
 334
 335         /**
 336          * Return the list of revision fields that should be selected to create
 337          * a new revision.
 338          * @return array
 339          */
 340         public static function selectFields() {
 341                 global $wgContentHandlerUseDB;
 342
 343                 $fields = array(
 344                         'rev_id',
 345                         'rev_page',
 346                         'rev_text_id',
 347                         'rev_timestamp',
 348                         'rev_comment',
 349                         'rev_user_text',
 350                         'rev_user',
 351                         'rev_minor_edit',
 352                         'rev_deleted',
 353                         'rev_len',
 354                         'rev_parent_id',
 355                         'rev_sha1',
 356                 );
 357
 358                 if ( $wgContentHandlerUseDB ) {
 359                         $fields[] = 'rev_content_format';
 360                         $fields[] = 'rev_content_model';
 361                 }
 362
 363                 return $fields;
 364         }
 365
 366         /**
 367          * Return the list of text fields that should be selected to read the
 368          * revision text
 369          * @return array
 370          */
 371         public static function selectTextFields() {
 372                 return array(
 373                         'old_text',
 374                         'old_flags'
 375                 );
 376         }
 377
 378         /**
 379          * Return the list of page fields that should be selected from page table
 380          * @return array
 381          */
 382         public static function selectPageFields() {
 383                 return array(
 384                         'page_namespace',
 385                         'page_title',
 386                         'page_id',
 387                         'page_latest'
 388                 );
 389         }
 390
 391         /**
 392          * Return the list of user fields that should be selected from user table
 393          * @return array
 394          */
 395         public static function selectUserFields() {
 396                 return array( 'user_name' );
 397         }
 398
 399         /**
 400          * Constructor
 401          *
 402          * @param $row Mixed: either a database row or an array
 403          * @access private
 404          */
 405         function __construct( $row ) {
 406                 if( is_object( $row ) ) {
 407                         $this->mId        = intval( $row->rev_id );
 408                         $this->mPage      = intval( $row->rev_page );
 409                         $this->mTextId    = intval( $row->rev_text_id );
 410                         $this->mComment   =         $row->rev_comment;
 411                         $this->mUser      = intval( $row->rev_user );
 412                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 413                         $this->mTimestamp =         $row->rev_timestamp;
 414                         $this->mDeleted   = intval( $row->rev_deleted );
 415
 416                         if( !isset( $row->rev_parent_id ) ) {
 417                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 418                         } else {
 419                                 $this->mParentId  = intval( $row->rev_parent_id );
 420                         }
 421
 422                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 423                                 $this->mSize = null;
 424                         } else {
 425                                 $this->mSize = intval( $row->rev_len );
 426                         }
 427
 428                         if ( !isset( $row->rev_sha1 ) ) {
 429                                 $this->mSha1 = null;
 430                         } else {
 431                                 $this->mSha1 = $row->rev_sha1;
 432                         }
 433
 434                         if( isset( $row->page_latest ) ) {
 435                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 436                                 $this->mTitle = Title::newFromRow( $row );
 437                         } else {
 438                                 $this->mCurrent = false;
 439                                 $this->mTitle = null;
 440                         }
 441
 442                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 443                                 $this->mContentModel = null; # determine on demand if needed
 444                         } else {
 445                                 $this->mContentModel = intval( $row->rev_content_model );
 446                         }
 447
 448                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 449                                 $this->mContentFormat = null; # determine on demand if needed
 450                         } else {
 451                                 $this->mContentFormat = intval( $row->rev_content_format );
 452                         }
 453
 454                         // Lazy extraction...
 455                         $this->mText      = null;
 456                         if( isset( $row->old_text ) ) {
 457                                 $this->mTextRow = $row;
 458                         } else {
 459                                 // 'text' table row entry will be lazy-loaded
 460                                 $this->mTextRow = null;
 461                         }
 462
 463                         // Use user_name for users and rev_user_text for IPs...
 464                         $this->mUserText = null; // lazy load if left null
 465                         if ( $this->mUser == 0 ) {
 466                                 $this->mUserText = $row->rev_user_text; // IP user
 467                         } elseif ( isset( $row->user_name ) ) {
 468                                 $this->mUserText = $row->user_name; // logged-in user
 469                         }
 470                         $this->mOrigUserText = $row->rev_user_text;
 471                 } elseif( is_array( $row ) ) {
 472                         // Build a new revision to be saved...
 473                         global $wgUser; // ugh
 474
 475
 476                         # if we have a content object, use it to set the model and type
 477                         if ( !empty( $row['content'] ) ) {
 478                                 if ( !empty( $row['text_id'] ) ) { #FIXME: when is that set? test with external store setup! check out insertOn()
 479                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), can't serialize content object" );
 480                                 }
 481
 482                                 $row['content_model'] = $row['content']->getModel();
 483                                 # note: mContentFormat is initializes later accordingly
 484                                 # note: content is serialized later in this method!
 485                                 # also set text to null?
 486                         }
 487
 488                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 489                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 490                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 491                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 492                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 493                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 494                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 495                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 496                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 497                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 498                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 499
 500                         $this->mContentModel = isset( $row['content_model']  )  ? intval( $row['content_model'] )  : null;
 501                         $this->mContentFormat    = isset( $row['content_format']  ) ? intval( $row['content_format'] ) : null;
 502
 503                         // Enforce spacing trimming on supplied text
 504                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 505                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 506                         $this->mTextRow   = null;
 507
 508                         # if we have a content object, override mText and mContentModel
 509                         if ( !empty( $row['content'] ) ) {
 510                                 $handler = $this->getContentHandler();
 511                                 $this->mContent = $row['content'];
 512
 513                                 $this->mContentModel = $this->mContent->getModel();
 514                                 $this->mContentHandler = null;
 515
 516                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 517                         } elseif ( !is_null( $this->mText ) ) {
 518                                 $handler = $this->getContentHandler();
 519                                 $this->mContent = $handler->unserializeContent( $this->mText );
 520                         }
 521
 522                         $this->mTitle     = null; # Load on demand if needed
 523                         $this->mCurrent   = false; #XXX: really? we are about to create a revision. it will usually then be the current one.
 524
 525                         # If we still have no length, see it we have the text to figure it out
 526                         if ( !$this->mSize ) {
 527                                 if ( !is_null( $this->mContent ) ) {
 528                                         $this->mSize = $this->mContent->getSize();
 529                                 } else {
 530                                         #XXX: my be inconsistent with the notion of "size" use for the present content model
 531                                         #NOTE: should never happen if we have either text or content object!
 532                                         $this->mSize = is_null( $this->mText ) ? null : strlen( $this->mText );
 533                                 }
 534                         }
 535
 536                         # Same for sha1
 537                         if ( $this->mSha1 === null ) {
 538                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 539                         }
 540
 541                         $this->getContentModel(); # force lazy init
 542                         $this->getContentFormat();    # force lazy init
 543                 } else {
 544                         throw new MWException( 'Revision constructor passed invalid row format.' );
 545                 }
 546                 $this->mUnpatrolled = null;
 547
 548                 // @TODO: add support for ar_content_format, ar_content_model, rev_content_format, rev_content_model to API
 549                 // @TODO: get rid of $mText
 550         }
 551
 552         /**
 553          * Get revision ID
 554          *
 555          * @return Integer
 556          */
 557         public function getId() {
 558                 return $this->mId;
 559         }
 560
 561         /**
 562          * Set the revision ID
 563          *
 564          * @since 1.19
 565          * @param $id Integer
 566          */
 567         public function setId( $id ) {
 568                 $this->mId = $id;
 569         }
 570
 571         /**
 572          * Get text row ID
 573          *
 574          * @return Integer
 575          */
 576         public function getTextId() {
 577                 return $this->mTextId;
 578         }
 579
 580         /**
 581          * Get parent revision ID (the original previous page revision)
 582          *
 583          * @return Integer|null
 584          */
 585         public function getParentId() {
 586                 return $this->mParentId;
 587         }
 588
 589         /**
 590          * Returns the length of the text in this revision, or null if unknown.
 591          *
 592          * @return Integer
 593          */
 594         public function getSize() {
 595                 return $this->mSize;
 596         }
 597
 598         /**
 599          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 600          *
 601          * @return String
 602          */
 603         public function getSha1() {
 604                 return $this->mSha1;
 605         }
 606
 607         /**
 608          * Returns the title of the page associated with this entry.
 609          *
 610          * @return Title
 611          */
 612         public function getTitle() {
 613                 if( isset( $this->mTitle ) ) {
 614                         return $this->mTitle;
 615                 }
 616                 $dbr = wfGetDB( DB_SLAVE );
 617                 $row = $dbr->selectRow(
 618                         array( 'page', 'revision' ),
 619                         self::selectPageFields(),
 620                         array( 'page_id=rev_page',
 621                                    'rev_id' => $this->mId ),
 622                         __METHOD__ );
 623                 if ( $row ) {
 624                         $this->mTitle = Title::newFromRow( $row );
 625                 }
 626                 return $this->mTitle;
 627         }
 628
 629         /**
 630          * Set the title of the revision
 631          *
 632          * @param $title Title
 633          */
 634         public function setTitle( $title ) {
 635                 $this->mTitle = $title;
 636         }
 637
 638         /**
 639          * Get the page ID
 640          *
 641          * @return Integer
 642          */
 643         public function getPage() {
 644                 return $this->mPage;
 645         }
 646
 647         /**
 648          * Fetch revision's user id if it's available to the specified audience.
 649          * If the specified audience does not have access to it, zero will be
 650          * returned.
 651          *
 652          * @param $audience Integer: one of:
 653          *      Revision::FOR_PUBLIC       to be displayed to all users
 654          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 655          *      Revision::RAW              get the ID regardless of permissions
 656          * @param $user User object to check for, only if FOR_THIS_USER is passed
 657          *              to the $audience parameter
 658          * @return Integer
 659          */
 660         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 661                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 662                         return 0;
 663                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 664                         return 0;
 665                 } else {
 666                         return $this->mUser;
 667                 }
 668         }
 669
 670         /**
 671          * Fetch revision's user id without regard for the current user's permissions
 672          *
 673          * @return String
 674          */
 675         public function getRawUser() {
 676                 return $this->mUser;
 677         }
 678
 679         /**
 680          * Fetch revision's username if it's available to the specified audience.
 681          * If the specified audience does not have access to the username, an
 682          * empty string will be returned.
 683          *
 684          * @param $audience Integer: one of:
 685          *      Revision::FOR_PUBLIC       to be displayed to all users
 686          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 687          *      Revision::RAW              get the text regardless of permissions
 688          * @param $user User object to check for, only if FOR_THIS_USER is passed
 689          *              to the $audience parameter
 690          * @return string
 691          */
 692         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 693                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 694                         return '';
 695                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 696                         return '';
 697                 } else {
 698                         return $this->getRawUserText();
 699                 }
 700         }
 701
 702         /**
 703          * Fetch revision's username without regard for view restrictions
 704          *
 705          * @return String
 706          */
 707         public function getRawUserText() {
 708                 if ( $this->mUserText === null ) {
 709                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 710                         if ( $this->mUserText === false ) {
 711                                 # This shouldn't happen, but it can if the wiki was recovered
 712                                 # via importing revs and there is no user table entry yet.
 713                                 $this->mUserText = $this->mOrigUserText;
 714                         }
 715                 }
 716                 return $this->mUserText;
 717         }
 718
 719         /**
 720          * Fetch revision comment if it's available to the specified audience.
 721          * If the specified audience does not have access to the comment, an
 722          * empty string will be returned.
 723          *
 724          * @param $audience Integer: one of:
 725          *      Revision::FOR_PUBLIC       to be displayed to all users
 726          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 727          *      Revision::RAW              get the text regardless of permissions
 728          * @param $user User object to check for, only if FOR_THIS_USER is passed
 729          *              to the $audience parameter
 730          * @return String
 731          */
 732         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 733                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 734                         return '';
 735                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 736                         return '';
 737                 } else {
 738                         return $this->mComment;
 739                 }
 740         }
 741
 742         /**
 743          * Fetch revision comment without regard for the current user's permissions
 744          *
 745          * @return String
 746          */
 747         public function getRawComment() {
 748                 return $this->mComment;
 749         }
 750
 751         /**
 752          * @return Boolean
 753          */
 754         public function isMinor() {
 755                 return (bool)$this->mMinorEdit;
 756         }
 757
 758         /**
 759          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 760          */
 761         public function isUnpatrolled() {
 762                 if( $this->mUnpatrolled !== null ) {
 763                         return $this->mUnpatrolled;
 764                 }
 765                 $dbr = wfGetDB( DB_SLAVE );
 766                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 767                         'rc_id',
 768                         array( // Add redundant user,timestamp condition so we can use the existing index
 769                                 'rc_user_text'  => $this->getRawUserText(),
 770                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 771                                 'rc_this_oldid' => $this->getId(),
 772                                 'rc_patrolled'  => 0
 773                         ),
 774                         __METHOD__
 775                 );
 776                 return (int)$this->mUnpatrolled;
 777         }
 778
 779         /**
 780          * @param $field int one of DELETED_* bitfield constants
 781          *
 782          * @return Boolean
 783          */
 784         public function isDeleted( $field ) {
 785                 return ( $this->mDeleted & $field ) == $field;
 786         }
 787
 788         /**
 789          * Get the deletion bitfield of the revision
 790          *
 791          * @return int
 792          */
 793         public function getVisibility() {
 794                 return (int)$this->mDeleted;
 795         }
 796
 797         /**
 798          * Fetch revision text if it's available to the specified audience.
 799          * If the specified audience does not have the ability to view this
 800          * revision, an empty string will be returned.
 801          *
 802          * @param $audience Integer: one of:
 803          *      Revision::FOR_PUBLIC       to be displayed to all users
 804          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 805          *      Revision::RAW              get the text regardless of permissions
 806          * @param $user User object to check for, only if FOR_THIS_USER is passed
 807          *              to the $audience parameter
 808          * @return String
 809          * @deprecated in 1.WD, use getContent() instead
 810          */
 811         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) { #FIXME: deprecated, replace usage! #FIXME: used a LOT!
 812                 wfDeprecated( __METHOD__, '1.WD' );
 813
 814                 $content = $this->getContent();
 815                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 816         }
 817
 818         /**
 819          * Fetch revision content if it's available to the specified audience.
 820          * If the specified audience does not have the ability to view this
 821          * revision, null will be returned.
 822          *
 823          * @param $audience Integer: one of:
 824          *      Revision::FOR_PUBLIC       to be displayed to all users
 825          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 826          *      Revision::RAW              get the text regardless of permissions
 827          * @param $user User object to check for, only if FOR_THIS_USER is passed
 828          *              to the $audience parameter
 829          * @return Content
 830          *
 831          * @since 1.WD
 832          */
 833         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 834                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 835                         return null;
 836                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 837                         return null;
 838                 } else {
 839                         return $this->getContentInternal();
 840                 }
 841         }
 842
 843         /**
 844          * Alias for getText(Revision::FOR_THIS_USER)
 845          *
 846          * @deprecated since 1.17
 847          * @return String
 848          */
 849         public function revText() {
 850                 wfDeprecated( __METHOD__, '1.17' );
 851                 return $this->getText( self::FOR_THIS_USER );
 852         }
 853
 854         /**
 855          * Fetch revision text without regard for view restrictions
 856          *
 857          * @return String
 858          */
 859         public function getRawText() { #FIXME: deprecated, replace usage!
 860                 return $this->getText( self::RAW );
 861         }
 862
 863         protected function getContentInternal() {
 864                 if( is_null( $this->mContent ) ) {
 865                         // Revision is immutable. Load on demand:
 866
 867                         $handler = $this->getContentHandler();
 868                         $format = $this->getContentFormat();
 869                         $title = $this->getTitle();
 870
 871                         if( is_null( $this->mText ) ) {
 872                                 // Load text on demand:
 873                                 $this->mText = $this->loadText();
 874                         }
 875
 876                         $this->mContent = is_null( $this->mText ) ? null : $handler->unserializeContent( $this->mText, $format );
 877                 }
 878
 879                 return $this->mContent;
 880         }
 881
 882         /**
 883          * Returns the content model for this revision.
 884          *
 885          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
 886          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
 887          * is used as a last resort.
 888          *
 889          * @return int the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
 890          **/
 891         public function getContentModel() {
 892                 if ( !$this->mContentModel ) {
 893                         $title = $this->getTitle();
 894                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
 895
 896                         assert( !empty( $this->mContentModel ) );
 897                 }
 898
 899                 return $this->mContentModel;
 900         }
 901
 902         /**
 903          * Returns the content format for this revision.
 904          *
 905          * If no content format was stored in the database, the default format for this
 906          * revision's content model is returned.
 907          *
 908          * @return int the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
 909          **/
 910         public function getContentFormat() {
 911                 if ( !$this->mContentFormat ) {
 912                         $handler = $this->getContentHandler();
 913                         $this->mContentFormat = $handler->getDefaultFormat();
 914
 915                         assert( !empty( $this->mContentFormat ) );
 916                 }
 917
 918                 return $this->mContentFormat;
 919         }
 920
 921         /**
 922          * Returns the content handler appropriate for this revision's content model.
 923          *
 924          * @return ContentHandler
 925          */
 926         public function getContentHandler() {
 927                 if ( !$this->mContentHandler ) {
 928                         $model = $this->getContentModel();
 929                         $this->mContentHandler = ContentHandler::getForModelID( $model );
 930
 931                         assert( $this->mContentHandler->isSupportedFormat( $this->getContentFormat() ) );
 932                 }
 933
 934                 return $this->mContentHandler;
 935         }
 936
 937         /**
 938          * @return String
 939          */
 940         public function getTimestamp() {
 941                 return wfTimestamp( TS_MW, $this->mTimestamp );
 942         }
 943
 944         /**
 945          * @return Boolean
 946          */
 947         public function isCurrent() {
 948                 return $this->mCurrent;
 949         }
 950
 951         /**
 952          * Get previous revision for this title
 953          *
 954          * @return Revision or null
 955          */
 956         public function getPrevious() {
 957                 if( $this->getTitle() ) {
 958                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 959                         if( $prev ) {
 960                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 961                         }
 962                 }
 963                 return null;
 964         }
 965
 966         /**
 967          * Get next revision for this title
 968          *
 969          * @return Revision or null
 970          */
 971         public function getNext() {
 972                 if( $this->getTitle() ) {
 973                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 974                         if ( $next ) {
 975                                 return Revision::newFromTitle( $this->getTitle(), $next );
 976                         }
 977                 }
 978                 return null;
 979         }
 980
 981         /**
 982          * Get previous revision Id for this page_id
 983          * This is used to populate rev_parent_id on save
 984          *
 985          * @param $db DatabaseBase
 986          * @return Integer
 987          */
 988         private function getPreviousRevisionId( $db ) {
 989                 if( is_null( $this->mPage ) ) {
 990                         return 0;
 991                 }
 992                 # Use page_latest if ID is not given
 993                 if( !$this->mId ) {
 994                         $prevId = $db->selectField( 'page', 'page_latest',
 995                                 array( 'page_id' => $this->mPage ),
 996                                 __METHOD__ );
 997                 } else {
 998                         $prevId = $db->selectField( 'revision', 'rev_id',
 999                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1000                                 __METHOD__,
1001                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1002                 }
1003                 return intval( $prevId );
1004         }
1005
1006         /**
1007           * Get revision text associated with an old or archive row
1008           * $row is usually an object from wfFetchRow(), both the flags and the text
1009           * field must be included
1010           *
1011           * @param $row Object: the text data
1012           * @param $prefix String: table prefix (default 'old_')
1013           * @return String: text the text requested or false on failure
1014           */
1015         public static function getRevisionText( $row, $prefix = 'old_' ) {
1016                 wfProfileIn( __METHOD__ );
1017
1018                 # Get data
1019                 $textField = $prefix . 'text';
1020                 $flagsField = $prefix . 'flags';
1021
1022                 if( isset( $row->$flagsField ) ) {
1023                         $flags = explode( ',', $row->$flagsField );
1024                 } else {
1025                         $flags = array();
1026                 }
1027
1028                 if( isset( $row->$textField ) ) {
1029                         $text = $row->$textField;
1030                 } else {
1031                         wfProfileOut( __METHOD__ );
1032                         return false;
1033                 }
1034
1035                 # Use external methods for external objects, text in table is URL-only then
1036                 if ( in_array( 'external', $flags ) ) {
1037                         $url = $text;
1038                         $parts = explode( '://', $url, 2 );
1039                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1040                                 wfProfileOut( __METHOD__ );
1041                                 return false;
1042                         }
1043                         $text = ExternalStore::fetchFromURL( $url );
1044                 }
1045
1046                 // If the text was fetched without an error, convert it
1047                 if ( $text !== false ) {
1048                         if( in_array( 'gzip', $flags ) ) {
1049                                 # Deal with optional compression of archived pages.
1050                                 # This can be done periodically via maintenance/compressOld.php, and
1051                                 # as pages are saved if $wgCompressRevisions is set.
1052                                 $text = gzinflate( $text );
1053                         }
1054
1055                         if( in_array( 'object', $flags ) ) {
1056                                 # Generic compressed storage
1057                                 $obj = unserialize( $text );
1058                                 if ( !is_object( $obj ) ) {
1059                                         // Invalid object
1060                                         wfProfileOut( __METHOD__ );
1061                                         return false;
1062                                 }
1063                                 $text = $obj->getText();
1064                         }
1065
1066                         global $wgLegacyEncoding;
1067                         if( $text !== false && $wgLegacyEncoding
1068                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1069                         {
1070                                 # Old revisions kept around in a legacy encoding?
1071                                 # Upconvert on demand.
1072                                 # ("utf8" checked for compatibility with some broken
1073                                 #  conversion scripts 2008-12-30)
1074                                 global $wgContLang;
1075                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1076                         }
1077                 }
1078                 wfProfileOut( __METHOD__ );
1079                 return $text;
1080         }
1081
1082         /**
1083          * If $wgCompressRevisions is enabled, we will compress data.
1084          * The input string is modified in place.
1085          * Return value is the flags field: contains 'gzip' if the
1086          * data is compressed, and 'utf-8' if we're saving in UTF-8
1087          * mode.
1088          *
1089          * @param $text Mixed: reference to a text
1090          * @return String
1091          */
1092         public static function compressRevisionText( &$text ) {
1093                 global $wgCompressRevisions;
1094                 $flags = array();
1095
1096                 # Revisions not marked this way will be converted
1097                 # on load if $wgLegacyCharset is set in the future.
1098                 $flags[] = 'utf-8';
1099
1100                 if( $wgCompressRevisions ) {
1101                         if( function_exists( 'gzdeflate' ) ) {
1102                                 $text = gzdeflate( $text );
1103                                 $flags[] = 'gzip';
1104                         } else {
1105                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
1106                         }
1107                 }
1108                 return implode( ',', $flags );
1109         }
1110
1111         /**
1112          * Insert a new revision into the database, returning the new revision ID
1113          * number on success and dies horribly on failure.
1114          *
1115          * @param $dbw DatabaseBase: (master connection)
1116          * @return Integer
1117          */
1118         public function insertOn( $dbw ) {
1119                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1120
1121                 wfProfileIn( __METHOD__ );
1122
1123                 $data = $this->mText;
1124                 $flags = Revision::compressRevisionText( $data );
1125
1126                 # Write to external storage if required
1127                 if( $wgDefaultExternalStore ) {
1128                         // Store and get the URL
1129                         $data = ExternalStore::insertToDefault( $data );
1130                         if( !$data ) {
1131                                 throw new MWException( "Unable to store text to external storage" );
1132                         }
1133                         if( $flags ) {
1134                                 $flags .= ',';
1135                         }
1136                         $flags .= 'external';
1137                 }
1138
1139                 # Record the text (or external storage URL) to the text table
1140                 if( !isset( $this->mTextId ) ) {
1141                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1142                         $dbw->insert( 'text',
1143                                 array(
1144                                         'old_id'    => $old_id,
1145                                         'old_text'  => $data,
1146                                         'old_flags' => $flags,
1147                                 ), __METHOD__
1148                         );
1149                         $this->mTextId = $dbw->insertId();
1150                 }
1151
1152                 if ( $this->mComment === null ) $this->mComment = "";
1153
1154                 # Record the edit in revisions
1155                 $rev_id = isset( $this->mId )
1156                         ? $this->mId
1157                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1158
1159                 $row = array(
1160                         'rev_id'         => $rev_id,
1161                         'rev_page'       => $this->mPage,
1162                         'rev_text_id'    => $this->mTextId,
1163                         'rev_comment'    => $this->mComment,
1164                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1165                         'rev_user'       => $this->mUser,
1166                         'rev_user_text'  => $this->mUserText,
1167                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1168                         'rev_deleted'    => $this->mDeleted,
1169                         'rev_len'        => $this->mSize,
1170                         'rev_parent_id'  => is_null( $this->mParentId )
1171                                 ? $this->getPreviousRevisionId( $dbw )
1172                                 : $this->mParentId,
1173                         'rev_sha1'       => is_null( $this->mSha1 )
1174                                 ? Revision::base36Sha1( $this->mText )
1175                                 : $this->mSha1,
1176                 );
1177
1178                 if ( $wgContentHandlerUseDB ) {
1179                         $row[ 'rev_content_model' ] = $this->getContentModel();
1180                         $row[ 'rev_content_format' ] = $this->getContentFormat();
1181                 }
1182
1183                 $dbw->insert( 'revision', $row, __METHOD__ );
1184
1185                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1186
1187                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1188
1189                 wfProfileOut( __METHOD__ );
1190                 return $this->mId;
1191         }
1192
1193         /**
1194          * Get the base 36 SHA-1 value for a string of text
1195          * @param $text String
1196          * @return String
1197          */
1198         public static function base36Sha1( $text ) {
1199                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1200         }
1201
1202         /**
1203          * Lazy-load the revision's text.
1204          * Currently hardcoded to the 'text' table storage engine.
1205          *
1206          * @return String
1207          */
1208         protected function loadText() {
1209                 wfProfileIn( __METHOD__ );
1210
1211                 // Caching may be beneficial for massive use of external storage
1212                 global $wgRevisionCacheExpiry, $wgMemc;
1213                 $textId = $this->getTextId();
1214                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1215                 if( $wgRevisionCacheExpiry ) {
1216                         $text = $wgMemc->get( $key );
1217                         if( is_string( $text ) ) {
1218                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1219                                 wfProfileOut( __METHOD__ );
1220                                 return $text;
1221                         }
1222                 }
1223
1224                 // If we kept data for lazy extraction, use it now...
1225                 if ( isset( $this->mTextRow ) ) {
1226                         $row = $this->mTextRow;
1227                         $this->mTextRow = null;
1228                 } else {
1229                         $row = null;
1230                 }
1231
1232                 if( !$row ) {
1233                         // Text data is immutable; check slaves first.
1234                         $dbr = wfGetDB( DB_SLAVE );
1235                         $row = $dbr->selectRow( 'text',
1236                                 array( 'old_text', 'old_flags' ),
1237                                 array( 'old_id' => $this->getTextId() ),
1238                                 __METHOD__ );
1239                 }
1240
1241                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1242                         // Possible slave lag!
1243                         $dbw = wfGetDB( DB_MASTER );
1244                         $row = $dbw->selectRow( 'text',
1245                                 array( 'old_text', 'old_flags' ),
1246                                 array( 'old_id' => $this->getTextId() ),
1247                                 __METHOD__ );
1248                 }
1249
1250                 $text = self::getRevisionText( $row );
1251
1252                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1253                 if( $wgRevisionCacheExpiry && $text !== false ) {
1254                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1255                 }
1256
1257                 wfProfileOut( __METHOD__ );
1258
1259                 return $text;
1260         }
1261
1262         /**
1263          * Create a new null-revision for insertion into a page's
1264          * history. This will not re-save the text, but simply refer
1265          * to the text from the previous version.
1266          *
1267          * Such revisions can for instance identify page rename
1268          * operations and other such meta-modifications.
1269          *
1270          * @param $dbw DatabaseBase
1271          * @param $pageId Integer: ID number of the page to read from
1272          * @param $summary String: revision's summary
1273          * @param $minor Boolean: whether the revision should be considered as minor
1274          * @return Revision|null on error
1275          */
1276         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1277                 global $wgContentHandlerUseDB;
1278
1279                 wfProfileIn( __METHOD__ );
1280
1281                 $fields = array( 'page_latest', 'rev_text_id', 'rev_len', 'rev_sha1' );
1282
1283                 if ( $wgContentHandlerUseDB ) {
1284                         $fields[] = 'rev_content_model';
1285                         $fields[] = 'rev_content_format';
1286                 }
1287
1288                 $current = $dbw->selectRow(
1289                         array( 'page', 'revision' ),
1290                         $fields,
1291                         array(
1292                                 'page_id' => $pageId,
1293                                 'page_latest=rev_id',
1294                                 ),
1295                         __METHOD__ );
1296
1297                 if( $current ) {
1298                         $row = array(
1299                                 'page'       => $pageId,
1300                                 'comment'    => $summary,
1301                                 'minor_edit' => $minor,
1302                                 'text_id'    => $current->rev_text_id,
1303                                 'parent_id'  => $current->page_latest,
1304                                 'len'        => $current->rev_len,
1305                                 'sha1'       => $current->rev_sha1,
1306                         );
1307
1308                         if ( $wgContentHandlerUseDB ) {
1309                                 $row[ 'content_model' ] = $current->rev_content_model;
1310                                 $row[ 'content_format' ] = $current->rev_content_format;
1311                         }
1312
1313                         $revision = new Revision( $row );
1314                 } else {
1315                         $revision = null;
1316                 }
1317
1318                 wfProfileOut( __METHOD__ );
1319                 return $revision;
1320         }
1321
1322         /**
1323          * Determine if the current user is allowed to view a particular
1324          * field of this revision, if it's marked as deleted.
1325          *
1326          * @param $field Integer:one of self::DELETED_TEXT,
1327          *                              self::DELETED_COMMENT,
1328          *                              self::DELETED_USER
1329          * @param $user User object to check, or null to use $wgUser
1330          * @return Boolean
1331          */
1332         public function userCan( $field, User $user = null ) {
1333                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1334         }
1335
1336         /**
1337          * Determine if the current user is allowed to view a particular
1338          * field of this revision, if it's marked as deleted. This is used
1339          * by various classes to avoid duplication.
1340          *
1341          * @param $bitfield Integer: current field
1342          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1343          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1344          *                               self::DELETED_USER = File::DELETED_USER
1345          * @param $user User object to check, or null to use $wgUser
1346          * @return Boolean
1347          */
1348         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1349                 if( $bitfield & $field ) { // aspect is deleted
1350                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1351                                 $permission = 'suppressrevision';
1352                         } elseif ( $field & self::DELETED_TEXT ) {
1353                                 $permission = 'deletedtext';
1354                         } else {
1355                                 $permission = 'deletedhistory';
1356                         }
1357                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1358                         if ( $user === null ) {
1359                                 global $wgUser;
1360                                 $user = $wgUser;
1361                         }
1362                         return $user->isAllowed( $permission );
1363                 } else {
1364                         return true;
1365                 }
1366         }
1367
1368         /**
1369          * Get rev_timestamp from rev_id, without loading the rest of the row
1370          *
1371          * @param $title Title
1372          * @param $id Integer
1373          * @return String
1374          */
1375         static function getTimestampFromId( $title, $id ) {
1376                 $dbr = wfGetDB( DB_SLAVE );
1377                 // Casting fix for DB2
1378                 if ( $id == '' ) {
1379                         $id = 0;
1380                 }
1381                 $conds = array( 'rev_id' => $id );
1382                 $conds['rev_page'] = $title->getArticleID();
1383                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1384                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1385                         # Not in slave, try master
1386                         $dbw = wfGetDB( DB_MASTER );
1387                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1388                 }
1389                 return wfTimestamp( TS_MW, $timestamp );
1390         }
1391
1392         /**
1393          * Get count of revisions per page...not very efficient
1394          *
1395          * @param $db DatabaseBase
1396          * @param $id Integer: page id
1397          * @return Integer
1398          */
1399         static function countByPageId( $db, $id ) {
1400                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1401                         array( 'rev_page' => $id ), __METHOD__ );
1402                 if( $row ) {
1403                         return $row->revCount;
1404                 }
1405                 return 0;
1406         }
1407
1408         /**
1409          * Get count of revisions per page...not very efficient
1410          *
1411          * @param $db DatabaseBase
1412          * @param $title Title
1413          * @return Integer
1414          */
1415         static function countByTitle( $db, $title ) {
1416                 $id = $title->getArticleID();
1417                 if( $id ) {
1418                         return Revision::countByPageId( $db, $id );
1419                 }
1420                 return 0;
1421         }
1422 }