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          * Do a batched query to get the parent revision lengths
 423          * @param $db DatabaseBase
 424          * @param $revIds Array
 425          * @return array
 426          */
 427         public static function getParentLengths( $db, array $revIds ) {
 428                 $revLens = array();
 429                 if ( !$revIds ) {
 430                         return $revLens; // empty
 431                 }
 432                 wfProfileIn( __METHOD__ );
 433                 $res = $db->select( 'revision',
 434                         array( 'rev_id', 'rev_len' ),
 435                         array( 'rev_id' => $revIds ),
 436                         __METHOD__ );
 437                 foreach ( $res as $row ) {
 438                         $revLens[$row->rev_id] = $row->rev_len;
 439                 }
 440                 wfProfileOut( __METHOD__ );
 441                 return $revLens;
 442         }
 443
 444         /**
 445          * Constructor
 446          *
 447          * @param $row Mixed: either a database row or an array
 448          * @access private
 449          */
 450         function __construct( $row ) {
 451                 if( is_object( $row ) ) {
 452                         $this->mId        = intval( $row->rev_id );
 453                         $this->mPage      = intval( $row->rev_page );
 454                         $this->mTextId    = intval( $row->rev_text_id );
 455                         $this->mComment   =         $row->rev_comment;
 456                         $this->mUser      = intval( $row->rev_user );
 457                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 458                         $this->mTimestamp =         $row->rev_timestamp;
 459                         $this->mDeleted   = intval( $row->rev_deleted );
 460
 461                         if( !isset( $row->rev_parent_id ) ) {
 462                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 463                         } else {
 464                                 $this->mParentId  = intval( $row->rev_parent_id );
 465                         }
 466
 467                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 468                                 $this->mSize = null;
 469                         } else {
 470                                 $this->mSize = intval( $row->rev_len );
 471                         }
 472
 473                         if ( !isset( $row->rev_sha1 ) ) {
 474                                 $this->mSha1 = null;
 475                         } else {
 476                                 $this->mSha1 = $row->rev_sha1;
 477                         }
 478
 479                         if( isset( $row->page_latest ) ) {
 480                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 481                                 $this->mTitle = Title::newFromRow( $row );
 482                         } else {
 483                                 $this->mCurrent = false;
 484                                 $this->mTitle = null;
 485                         }
 486
 487                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 488                                 $this->mContentModel = null; # determine on demand if needed
 489                         } else {
 490                                 $this->mContentModel = strval( $row->rev_content_model );
 491                         }
 492
 493                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 494                                 $this->mContentFormat = null; # determine on demand if needed
 495                         } else {
 496                                 $this->mContentFormat = strval( $row->rev_content_format );
 497                         }
 498
 499                         // Lazy extraction...
 500                         $this->mText      = null;
 501                         if( isset( $row->old_text ) ) {
 502                                 $this->mTextRow = $row;
 503                         } else {
 504                                 // 'text' table row entry will be lazy-loaded
 505                                 $this->mTextRow = null;
 506                         }
 507
 508                         // Use user_name for users and rev_user_text for IPs...
 509                         $this->mUserText = null; // lazy load if left null
 510                         if ( $this->mUser == 0 ) {
 511                                 $this->mUserText = $row->rev_user_text; // IP user
 512                         } elseif ( isset( $row->user_name ) ) {
 513                                 $this->mUserText = $row->user_name; // logged-in user
 514                         }
 515                         $this->mOrigUserText = $row->rev_user_text;
 516                 } elseif( is_array( $row ) ) {
 517                         // Build a new revision to be saved...
 518                         global $wgUser; // ugh
 519
 520
 521                         # if we have a content object, use it to set the model and type
 522                         if ( !empty( $row['content'] ) ) {
 523                                 if ( !empty( $row['text_id'] ) ) { //@todo: when is that set? test with external store setup! check out insertOn() [dk]
 524                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), can't serialize content object" );
 525                                 }
 526
 527                                 $row['content_model'] = $row['content']->getModel();
 528                                 # note: mContentFormat is initializes later accordingly
 529                                 # note: content is serialized later in this method!
 530                                 # also set text to null?
 531                         }
 532
 533                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 534                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 535                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 536                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 537                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 538                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 539                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 540                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 541                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 542                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 543                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 544
 545                         $this->mContentModel = isset( $row['content_model']  )  ? strval( $row['content_model'] )  : null;
 546                         $this->mContentFormat    = isset( $row['content_format']  ) ? strval( $row['content_format'] ) : null;
 547
 548                         // Enforce spacing trimming on supplied text
 549                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 550                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 551                         $this->mTextRow   = null;
 552
 553                         $this->mTitle     = isset( $row['title']      ) ? $row['title'] : null;
 554
 555                         // if we have a Content object, override mText and mContentModel
 556                         if ( !empty( $row['content'] ) ) {
 557                                 $handler = $this->getContentHandler();
 558                                 $this->mContent = $row['content'];
 559
 560                                 $this->mContentModel = $this->mContent->getModel();
 561                                 $this->mContentHandler = null;
 562
 563                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 564                         } elseif ( !is_null( $this->mText ) ) {
 565                                 $handler = $this->getContentHandler();
 566                                 $this->mContent = $handler->unserializeContent( $this->mText );
 567                         }
 568
 569                         // if we have a Title object, override mPage. Useful for testing and convenience.
 570                         if ( isset( $row['title'] ) ) {
 571                                 $this->mTitle     = $row['title'];
 572                                 $this->mPage      = $this->mTitle->getArticleID();
 573                         } else {
 574                                 $this->mTitle     = null; // Load on demand if needed
 575                         }
 576
 577                         $this->mCurrent   = false; // @todo: XXX: really? we are about to create a revision. it will usually then be the current one.
 578
 579                         // If we still have no length, see it we have the text to figure it out
 580                         if ( !$this->mSize ) {
 581                                 if ( !is_null( $this->mContent ) ) {
 582                                         $this->mSize = $this->mContent->getSize();
 583                                 } else {
 584                                         #NOTE: this should never happen if we have either text or content object!
 585                                         $this->mSize = null;
 586                                 }
 587                         }
 588
 589                         // Same for sha1
 590                         if ( $this->mSha1 === null ) {
 591                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 592                         }
 593
 594                         // force lazy init
 595                         $this->getContentModel();
 596                         $this->getContentFormat();
 597                 } else {
 598                         throw new MWException( 'Revision constructor passed invalid row format.' );
 599                 }
 600                 $this->mUnpatrolled = null;
 601         }
 602
 603         /**
 604          * Get revision ID
 605          *
 606          * @return Integer|null
 607          */
 608         public function getId() {
 609                 return $this->mId;
 610         }
 611
 612         /**
 613          * Set the revision ID
 614          *
 615          * @since 1.19
 616          * @param $id Integer
 617          */
 618         public function setId( $id ) {
 619                 $this->mId = $id;
 620         }
 621
 622         /**
 623          * Get text row ID
 624          *
 625          * @return Integer|null
 626          */
 627         public function getTextId() {
 628                 return $this->mTextId;
 629         }
 630
 631         /**
 632          * Get parent revision ID (the original previous page revision)
 633          *
 634          * @return Integer|null
 635          */
 636         public function getParentId() {
 637                 return $this->mParentId;
 638         }
 639
 640         /**
 641          * Returns the length of the text in this revision, or null if unknown.
 642          *
 643          * @return Integer|null
 644          */
 645         public function getSize() {
 646                 return $this->mSize;
 647         }
 648
 649         /**
 650          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 651          *
 652          * @return String|null
 653          */
 654         public function getSha1() {
 655                 return $this->mSha1;
 656         }
 657
 658         /**
 659          * Returns the title of the page associated with this entry or null.
 660          *
 661          * Will do a query, when title is not set and id is given.
 662          *
 663          * @return Title|null
 664          */
 665         public function getTitle() {
 666                 if( isset( $this->mTitle ) ) {
 667                         return $this->mTitle;
 668                 }
 669                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 670                         $dbr = wfGetDB( DB_SLAVE );
 671                         $row = $dbr->selectRow(
 672                                 array( 'page', 'revision' ),
 673                                 self::selectPageFields(),
 674                                 array( 'page_id=rev_page',
 675                                            'rev_id' => $this->mId ),
 676                                 __METHOD__ );
 677                         if ( $row ) {
 678                                 $this->mTitle = Title::newFromRow( $row );
 679                         }
 680                 }
 681
 682                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 683                         $this->mTitle = Title::newFromID( $this->mPage );
 684                 }
 685
 686                 return $this->mTitle;
 687         }
 688
 689         /**
 690          * Set the title of the revision
 691          *
 692          * @param $title Title
 693          */
 694         public function setTitle( $title ) {
 695                 $this->mTitle = $title;
 696         }
 697
 698         /**
 699          * Get the page ID
 700          *
 701          * @return Integer|null
 702          */
 703         public function getPage() {
 704                 return $this->mPage;
 705         }
 706
 707         /**
 708          * Fetch revision's user id if it's available to the specified audience.
 709          * If the specified audience does not have access to it, zero will be
 710          * returned.
 711          *
 712          * @param $audience Integer: one of:
 713          *      Revision::FOR_PUBLIC       to be displayed to all users
 714          *      Revision::FOR_THIS_USER    to be displayed to the given user
 715          *      Revision::RAW              get the ID regardless of permissions
 716          * @param $user User object to check for, only if FOR_THIS_USER is passed
 717          *              to the $audience parameter
 718          * @return Integer
 719          */
 720         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 721                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 722                         return 0;
 723                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 724                         return 0;
 725                 } else {
 726                         return $this->mUser;
 727                 }
 728         }
 729
 730         /**
 731          * Fetch revision's user id without regard for the current user's permissions
 732          *
 733          * @return String
 734          */
 735         public function getRawUser() {
 736                 return $this->mUser;
 737         }
 738
 739         /**
 740          * Fetch revision's username if it's available to the specified audience.
 741          * If the specified audience does not have access to the username, an
 742          * empty string will be returned.
 743          *
 744          * @param $audience Integer: one of:
 745          *      Revision::FOR_PUBLIC       to be displayed to all users
 746          *      Revision::FOR_THIS_USER    to be displayed to the given user
 747          *      Revision::RAW              get the text regardless of permissions
 748          * @param $user User object to check for, only if FOR_THIS_USER is passed
 749          *              to the $audience parameter
 750          * @return string
 751          */
 752         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 753                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 754                         return '';
 755                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 756                         return '';
 757                 } else {
 758                         return $this->getRawUserText();
 759                 }
 760         }
 761
 762         /**
 763          * Fetch revision's username without regard for view restrictions
 764          *
 765          * @return String
 766          */
 767         public function getRawUserText() {
 768                 if ( $this->mUserText === null ) {
 769                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 770                         if ( $this->mUserText === false ) {
 771                                 # This shouldn't happen, but it can if the wiki was recovered
 772                                 # via importing revs and there is no user table entry yet.
 773                                 $this->mUserText = $this->mOrigUserText;
 774                         }
 775                 }
 776                 return $this->mUserText;
 777         }
 778
 779         /**
 780          * Fetch revision comment if it's available to the specified audience.
 781          * If the specified audience does not have access to the comment, an
 782          * empty string will be returned.
 783          *
 784          * @param $audience Integer: one of:
 785          *      Revision::FOR_PUBLIC       to be displayed to all users
 786          *      Revision::FOR_THIS_USER    to be displayed to the given user
 787          *      Revision::RAW              get the text regardless of permissions
 788          * @param $user User object to check for, only if FOR_THIS_USER is passed
 789          *              to the $audience parameter
 790          * @return String
 791          */
 792         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 793                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 794                         return '';
 795                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 796                         return '';
 797                 } else {
 798                         return $this->mComment;
 799                 }
 800         }
 801
 802         /**
 803          * Fetch revision comment without regard for the current user's permissions
 804          *
 805          * @return String
 806          */
 807         public function getRawComment() {
 808                 return $this->mComment;
 809         }
 810
 811         /**
 812          * @return Boolean
 813          */
 814         public function isMinor() {
 815                 return (bool)$this->mMinorEdit;
 816         }
 817
 818         /**
 819          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 820          */
 821         public function isUnpatrolled() {
 822                 if( $this->mUnpatrolled !== null ) {
 823                         return $this->mUnpatrolled;
 824                 }
 825                 $dbr = wfGetDB( DB_SLAVE );
 826                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 827                         'rc_id',
 828                         array( // Add redundant user,timestamp condition so we can use the existing index
 829                                 'rc_user_text'  => $this->getRawUserText(),
 830                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 831                                 'rc_this_oldid' => $this->getId(),
 832                                 'rc_patrolled'  => 0
 833                         ),
 834                         __METHOD__
 835                 );
 836                 return (int)$this->mUnpatrolled;
 837         }
 838
 839         /**
 840          * @param $field int one of DELETED_* bitfield constants
 841          *
 842          * @return Boolean
 843          */
 844         public function isDeleted( $field ) {
 845                 return ( $this->mDeleted & $field ) == $field;
 846         }
 847
 848         /**
 849          * Get the deletion bitfield of the revision
 850          *
 851          * @return int
 852          */
 853         public function getVisibility() {
 854                 return (int)$this->mDeleted;
 855         }
 856
 857         /**
 858          * Fetch revision text if it's available to the specified audience.
 859          * If the specified audience does not have the ability to view this
 860          * revision, an empty string will be returned.
 861          *
 862          * @param $audience Integer: one of:
 863          *      Revision::FOR_PUBLIC       to be displayed to all users
 864          *      Revision::FOR_THIS_USER    to be displayed to the given user
 865          *      Revision::RAW              get the text regardless of permissions
 866          * @param $user User object to check for, only if FOR_THIS_USER is passed
 867          *              to the $audience parameter
 868          * @return String
 869          * @deprecated in 1.WD, use getContent() instead
 870          * @todo: replace usage in core
 871          */
 872         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 873                 wfDeprecated( __METHOD__, '1.WD' );
 874
 875                 $content = $this->getContent( $audience, $user );
 876                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 877         }
 878
 879         /**
 880          * Fetch revision content if it's available to the specified audience.
 881          * If the specified audience does not have the ability to view this
 882          * revision, null will be returned.
 883          *
 884          * @param $audience Integer: one of:
 885          *      Revision::FOR_PUBLIC       to be displayed to all users
 886          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 887          *      Revision::RAW              get the text regardless of permissions
 888          * @param $user User object to check for, only if FOR_THIS_USER is passed
 889          *              to the $audience parameter
 890          * @return Content
 891          *
 892          * @since 1.WD
 893          */
 894         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 895                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 896                         return null;
 897                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 898                         return null;
 899                 } else {
 900                         return $this->getContentInternal();
 901                 }
 902         }
 903
 904         /**
 905          * Alias for getText(Revision::FOR_THIS_USER)
 906          *
 907          * @deprecated since 1.17
 908          * @return String
 909          */
 910         public function revText() {
 911                 wfDeprecated( __METHOD__, '1.17' );
 912                 return $this->getText( self::FOR_THIS_USER );
 913         }
 914
 915         /**
 916          * Fetch revision text without regard for view restrictions
 917          *
 918          * @return String
 919          *
 920          * @deprecated since 1.WD. Instead, use Revision::getContent( Revision::RAW ) or Revision::getSerializedData() as appropriate.
 921          */
 922         public function getRawText() {
 923                 wfDeprecated( __METHOD__, "1.WD" );
 924
 925                 return $this->getText( self::RAW );
 926         }
 927
 928         /**
 929          * Fetch original serialized data without regard for view restrictions
 930          *
 931          * @return String
 932          *
 933          * @since 1.WD
 934          */
 935         public function getSerializedData() {
 936                 return $this->mText;
 937         }
 938
 939         protected function getContentInternal() {
 940                 if( is_null( $this->mContent ) ) {
 941                         // Revision is immutable. Load on demand:
 942
 943                         $handler = $this->getContentHandler();
 944                         $format = $this->getContentFormat();
 945                         $title = $this->getTitle();
 946
 947                         if( is_null( $this->mText ) ) {
 948                                 // Load text on demand:
 949                                 $this->mText = $this->loadText();
 950                         }
 951
 952                         $this->mContent = is_null( $this->mText ) ? null : $handler->unserializeContent( $this->mText, $format );
 953                 }
 954
 955                 return $this->mContent;
 956         }
 957
 958         /**
 959          * Returns the content model for this revision.
 960          *
 961          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
 962          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
 963          * is used as a last resort.
 964          *
 965          * @return String the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
 966          **/
 967         public function getContentModel() {
 968                 if ( !$this->mContentModel ) {
 969                         $title = $this->getTitle();
 970                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
 971
 972                         assert( !empty( $this->mContentModel ) );
 973                 }
 974
 975                 return $this->mContentModel;
 976         }
 977
 978         /**
 979          * Returns the content format for this revision.
 980          *
 981          * If no content format was stored in the database, the default format for this
 982          * revision's content model is returned.
 983          *
 984          * @return String the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
 985          **/
 986         public function getContentFormat() {
 987                 if ( !$this->mContentFormat ) {
 988                         $handler = $this->getContentHandler();
 989                         $this->mContentFormat = $handler->getDefaultFormat();
 990
 991                         assert( !empty( $this->mContentFormat ) );
 992                 }
 993
 994                 return $this->mContentFormat;
 995         }
 996
 997         /**
 998          * Returns the content handler appropriate for this revision's content model.
 999          *
1000          * @return ContentHandler
1001          */
1002         public function getContentHandler() {
1003                 if ( !$this->mContentHandler ) {
1004                         $model = $this->getContentModel();
1005                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1006
1007                         $format = $this->getContentFormat();
1008
1009                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1010                                 throw new MWException( "Oops, the content format $format is not supported for this content model, $model" );
1011                         }
1012                 }
1013
1014                 return $this->mContentHandler;
1015         }
1016
1017         /**
1018          * @return String
1019          */
1020         public function getTimestamp() {
1021                 return wfTimestamp( TS_MW, $this->mTimestamp );
1022         }
1023
1024         /**
1025          * @return Boolean
1026          */
1027         public function isCurrent() {
1028                 return $this->mCurrent;
1029         }
1030
1031         /**
1032          * Get previous revision for this title
1033          *
1034          * @return Revision or null
1035          */
1036         public function getPrevious() {
1037                 if( $this->getTitle() ) {
1038                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1039                         if( $prev ) {
1040                                 return Revision::newFromTitle( $this->getTitle(), $prev );
1041                         }
1042                 }
1043                 return null;
1044         }
1045
1046         /**
1047          * Get next revision for this title
1048          *
1049          * @return Revision or null
1050          */
1051         public function getNext() {
1052                 if( $this->getTitle() ) {
1053                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1054                         if ( $next ) {
1055                                 return Revision::newFromTitle( $this->getTitle(), $next );
1056                         }
1057                 }
1058                 return null;
1059         }
1060
1061         /**
1062          * Get previous revision Id for this page_id
1063          * This is used to populate rev_parent_id on save
1064          *
1065          * @param $db DatabaseBase
1066          * @return Integer
1067          */
1068         private function getPreviousRevisionId( $db ) {
1069                 if( is_null( $this->mPage ) ) {
1070                         return 0;
1071                 }
1072                 # Use page_latest if ID is not given
1073                 if( !$this->mId ) {
1074                         $prevId = $db->selectField( 'page', 'page_latest',
1075                                 array( 'page_id' => $this->mPage ),
1076                                 __METHOD__ );
1077                 } else {
1078                         $prevId = $db->selectField( 'revision', 'rev_id',
1079                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1080                                 __METHOD__,
1081                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1082                 }
1083                 return intval( $prevId );
1084         }
1085
1086         /**
1087           * Get revision text associated with an old or archive row
1088           * $row is usually an object from wfFetchRow(), both the flags and the text
1089           * field must be included
1090           *
1091           * @param $row Object: the text data
1092           * @param $prefix String: table prefix (default 'old_')
1093           * @return String: text the text requested or false on failure
1094           */
1095         public static function getRevisionText( $row, $prefix = 'old_' ) {
1096                 wfProfileIn( __METHOD__ );
1097
1098                 # Get data
1099                 $textField = $prefix . 'text';
1100                 $flagsField = $prefix . 'flags';
1101
1102                 if( isset( $row->$flagsField ) ) {
1103                         $flags = explode( ',', $row->$flagsField );
1104                 } else {
1105                         $flags = array();
1106                 }
1107
1108                 if( isset( $row->$textField ) ) {
1109                         $text = $row->$textField;
1110                 } else {
1111                         wfProfileOut( __METHOD__ );
1112                         return false;
1113                 }
1114
1115                 # Use external methods for external objects, text in table is URL-only then
1116                 if ( in_array( 'external', $flags ) ) {
1117                         $url = $text;
1118                         $parts = explode( '://', $url, 2 );
1119                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1120                                 wfProfileOut( __METHOD__ );
1121                                 return false;
1122                         }
1123                         $text = ExternalStore::fetchFromURL( $url );
1124                 }
1125
1126                 // If the text was fetched without an error, convert it
1127                 if ( $text !== false ) {
1128                         if( in_array( 'gzip', $flags ) ) {
1129                                 # Deal with optional compression of archived pages.
1130                                 # This can be done periodically via maintenance/compressOld.php, and
1131                                 # as pages are saved if $wgCompressRevisions is set.
1132                                 $text = gzinflate( $text );
1133                         }
1134
1135                         if( in_array( 'object', $flags ) ) {
1136                                 # Generic compressed storage
1137                                 $obj = unserialize( $text );
1138                                 if ( !is_object( $obj ) ) {
1139                                         // Invalid object
1140                                         wfProfileOut( __METHOD__ );
1141                                         return false;
1142                                 }
1143                                 $text = $obj->getText();
1144                         }
1145
1146                         global $wgLegacyEncoding;
1147                         if( $text !== false && $wgLegacyEncoding
1148                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1149                         {
1150                                 # Old revisions kept around in a legacy encoding?
1151                                 # Upconvert on demand.
1152                                 # ("utf8" checked for compatibility with some broken
1153                                 #  conversion scripts 2008-12-30)
1154                                 global $wgContLang;
1155                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1156                         }
1157                 }
1158                 wfProfileOut( __METHOD__ );
1159                 return $text;
1160         }
1161
1162         /**
1163          * If $wgCompressRevisions is enabled, we will compress data.
1164          * The input string is modified in place.
1165          * Return value is the flags field: contains 'gzip' if the
1166          * data is compressed, and 'utf-8' if we're saving in UTF-8
1167          * mode.
1168          *
1169          * @param $text Mixed: reference to a text
1170          * @return String
1171          */
1172         public static function compressRevisionText( &$text ) {
1173                 global $wgCompressRevisions;
1174                 $flags = array();
1175
1176                 # Revisions not marked this way will be converted
1177                 # on load if $wgLegacyCharset is set in the future.
1178                 $flags[] = 'utf-8';
1179
1180                 if( $wgCompressRevisions ) {
1181                         if( function_exists( 'gzdeflate' ) ) {
1182                                 $text = gzdeflate( $text );
1183                                 $flags[] = 'gzip';
1184                         } else {
1185                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
1186                         }
1187                 }
1188                 return implode( ',', $flags );
1189         }
1190
1191         /**
1192          * Insert a new revision into the database, returning the new revision ID
1193          * number on success and dies horribly on failure.
1194          *
1195          * @param $dbw DatabaseBase: (master connection)
1196          * @return Integer
1197          */
1198         public function insertOn( $dbw ) {
1199                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1200
1201                 wfProfileIn( __METHOD__ );
1202
1203                 $this->checkContentModel();
1204
1205                 $data = $this->mText;
1206                 $flags = Revision::compressRevisionText( $data );
1207
1208                 # Write to external storage if required
1209                 if( $wgDefaultExternalStore ) {
1210                         // Store and get the URL
1211                         $data = ExternalStore::insertToDefault( $data );
1212                         if( !$data ) {
1213                                 throw new MWException( "Unable to store text to external storage" );
1214                         }
1215                         if( $flags ) {
1216                                 $flags .= ',';
1217                         }
1218                         $flags .= 'external';
1219                 }
1220
1221                 # Record the text (or external storage URL) to the text table
1222                 if( !isset( $this->mTextId ) ) {
1223                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1224                         $dbw->insert( 'text',
1225                                 array(
1226                                         'old_id'    => $old_id,
1227                                         'old_text'  => $data,
1228                                         'old_flags' => $flags,
1229                                 ), __METHOD__
1230                         );
1231                         $this->mTextId = $dbw->insertId();
1232                 }
1233
1234                 if ( $this->mComment === null ) $this->mComment = "";
1235
1236                 # Record the edit in revisions
1237                 $rev_id = isset( $this->mId )
1238                         ? $this->mId
1239                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1240
1241                 $row = array(
1242                         'rev_id'         => $rev_id,
1243                         'rev_page'       => $this->mPage,
1244                         'rev_text_id'    => $this->mTextId,
1245                         'rev_comment'    => $this->mComment,
1246                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1247                         'rev_user'       => $this->mUser,
1248                         'rev_user_text'  => $this->mUserText,
1249                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1250                         'rev_deleted'    => $this->mDeleted,
1251                         'rev_len'        => $this->mSize,
1252                         'rev_parent_id'  => is_null( $this->mParentId )
1253                                 ? $this->getPreviousRevisionId( $dbw )
1254                                 : $this->mParentId,
1255                         'rev_sha1'       => is_null( $this->mSha1 )
1256                                 ? Revision::base36Sha1( $this->mText )
1257                                 : $this->mSha1,
1258                 );
1259
1260                 if ( $wgContentHandlerUseDB ) {
1261                         //NOTE: Store null for the default model and format, to save space.
1262                         //XXX: Makes the DB sensitive to changed defaults. Make this behaviour optional? Only in miser mode?
1263
1264                         $model = $this->getContentModel();
1265                         $format = $this->getContentFormat();
1266
1267                         $defaultModel = ContentHandler::getDefaultModelFor( $this->getTitle() );
1268                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1269
1270                         $row[ 'rev_content_model' ] = ( $model === $defaultModel ) ? null : $model;
1271                         $row[ 'rev_content_format' ] = ( $format === $defaultFormat ) ? null : $format;
1272                 }
1273
1274                 $dbw->insert( 'revision', $row, __METHOD__ );
1275
1276                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1277
1278                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1279
1280                 wfProfileOut( __METHOD__ );
1281                 return $this->mId;
1282         }
1283
1284         protected function checkContentModel() {
1285                 global $wgContentHandlerUseDB;
1286
1287                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1288
1289                 $model = $this->getContentModel();
1290                 $format = $this->getContentFormat();
1291                 $handler = $this->getContentHandler();
1292
1293                 if ( !$handler->isSupportedFormat( $format ) ) {
1294                         $t = $title->getPrefixedDBkey();
1295
1296                         throw new MWException( "Can't use format $format with content model $model on $t" );
1297                 }
1298
1299                 if ( !$wgContentHandlerUseDB && $title ) {
1300                         // if $wgContentHandlerUseDB is not set, all revisions must use the default content model and format.
1301
1302                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1303                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1304                         $defaultFormat = $defaultHandler->getDefaultFormat();
1305
1306                         if ( $this->getContentModel() != $defaultModel ) {
1307                                 $t = $title->getPrefixedDBkey();
1308
1309                                 throw new MWException( "Can't save non-default content model with \$wgContentHandlerUseDB disabled: model is $model , default for $t is $defaultModel" );
1310                         }
1311
1312                         if ( $this->getContentFormat() != $defaultFormat ) {
1313                                 $t = $title->getPrefixedDBkey();
1314
1315                                 throw new MWException( "Can't use non-default content format with \$wgContentHandlerUseDB disabled: format is $format, default for $t is $defaultFormat" );
1316                         }
1317                 }
1318
1319                 $content = $this->getContent( Revision::RAW );
1320
1321                 if ( !$content->isValid() ) {
1322                         $t = $title->getPrefixedDBkey();
1323
1324                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1325                 }
1326         }
1327
1328         /**
1329          * Get the base 36 SHA-1 value for a string of text
1330          * @param $text String
1331          * @return String
1332          */
1333         public static function base36Sha1( $text ) {
1334                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1335         }
1336
1337         /**
1338          * Lazy-load the revision's text.
1339          * Currently hardcoded to the 'text' table storage engine.
1340          *
1341          * @return String
1342          */
1343         protected function loadText() {
1344                 wfProfileIn( __METHOD__ );
1345
1346                 // Caching may be beneficial for massive use of external storage
1347                 global $wgRevisionCacheExpiry, $wgMemc;
1348                 $textId = $this->getTextId();
1349                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1350                 if( $wgRevisionCacheExpiry ) {
1351                         $text = $wgMemc->get( $key );
1352                         if( is_string( $text ) ) {
1353                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1354                                 wfProfileOut( __METHOD__ );
1355                                 return $text;
1356                         }
1357                 }
1358
1359                 // If we kept data for lazy extraction, use it now...
1360                 if ( isset( $this->mTextRow ) ) {
1361                         $row = $this->mTextRow;
1362                         $this->mTextRow = null;
1363                 } else {
1364                         $row = null;
1365                 }
1366
1367                 if( !$row ) {
1368                         // Text data is immutable; check slaves first.
1369                         $dbr = wfGetDB( DB_SLAVE );
1370                         $row = $dbr->selectRow( 'text',
1371                                 array( 'old_text', 'old_flags' ),
1372                                 array( 'old_id' => $this->getTextId() ),
1373                                 __METHOD__ );
1374                 }
1375
1376                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1377                         // Possible slave lag!
1378                         $dbw = wfGetDB( DB_MASTER );
1379                         $row = $dbw->selectRow( 'text',
1380                                 array( 'old_text', 'old_flags' ),
1381                                 array( 'old_id' => $this->getTextId() ),
1382                                 __METHOD__ );
1383                 }
1384
1385                 $text = self::getRevisionText( $row );
1386
1387                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1388                 if( $wgRevisionCacheExpiry && $text !== false ) {
1389                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1390                 }
1391
1392                 wfProfileOut( __METHOD__ );
1393
1394                 return $text;
1395         }
1396
1397         /**
1398          * Create a new null-revision for insertion into a page's
1399          * history. This will not re-save the text, but simply refer
1400          * to the text from the previous version.
1401          *
1402          * Such revisions can for instance identify page rename
1403          * operations and other such meta-modifications.
1404          *
1405          * @param $dbw DatabaseBase
1406          * @param $pageId Integer: ID number of the page to read from
1407          * @param $summary String: revision's summary
1408          * @param $minor Boolean: whether the revision should be considered as minor
1409          * @return Revision|null on error
1410          */
1411         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1412                 global $wgContentHandlerUseDB;
1413
1414                 wfProfileIn( __METHOD__ );
1415
1416                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1417                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1418
1419                 if ( $wgContentHandlerUseDB ) {
1420                         $fields[] = 'rev_content_model';
1421                         $fields[] = 'rev_content_format';
1422                 }
1423
1424                 $current = $dbw->selectRow(
1425                         array( 'page', 'revision' ),
1426                         $fields,
1427                         array(
1428                                 'page_id' => $pageId,
1429                                 'page_latest=rev_id',
1430                                 ),
1431                         __METHOD__ );
1432
1433                 if( $current ) {
1434                         $row = array(
1435                                 'page'       => $pageId,
1436                                 'comment'    => $summary,
1437                                 'minor_edit' => $minor,
1438                                 'text_id'    => $current->rev_text_id,
1439                                 'parent_id'  => $current->page_latest,
1440                                 'len'        => $current->rev_len,
1441                                 'sha1'       => $current->rev_sha1
1442                         );
1443
1444                         if ( $wgContentHandlerUseDB ) {
1445                                 $row[ 'content_model' ] = $current->rev_content_model;
1446                                 $row[ 'content_format' ] = $current->rev_content_format;
1447                         }
1448
1449                         $revision = new Revision( $row );
1450                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1451                 } else {
1452                         $revision = null;
1453                 }
1454
1455                 wfProfileOut( __METHOD__ );
1456                 return $revision;
1457         }
1458
1459         /**
1460          * Determine if the current user is allowed to view a particular
1461          * field of this revision, if it's marked as deleted.
1462          *
1463          * @param $field Integer:one of self::DELETED_TEXT,
1464          *                              self::DELETED_COMMENT,
1465          *                              self::DELETED_USER
1466          * @param $user User object to check, or null to use $wgUser
1467          * @return Boolean
1468          */
1469         public function userCan( $field, User $user = null ) {
1470                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1471         }
1472
1473         /**
1474          * Determine if the current user is allowed to view a particular
1475          * field of this revision, if it's marked as deleted. This is used
1476          * by various classes to avoid duplication.
1477          *
1478          * @param $bitfield Integer: current field
1479          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1480          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1481          *                               self::DELETED_USER = File::DELETED_USER
1482          * @param $user User object to check, or null to use $wgUser
1483          * @return Boolean
1484          */
1485         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1486                 if( $bitfield & $field ) { // aspect is deleted
1487                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1488                                 $permission = 'suppressrevision';
1489                         } elseif ( $field & self::DELETED_TEXT ) {
1490                                 $permission = 'deletedtext';
1491                         } else {
1492                                 $permission = 'deletedhistory';
1493                         }
1494                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1495                         if ( $user === null ) {
1496                                 global $wgUser;
1497                                 $user = $wgUser;
1498                         }
1499                         return $user->isAllowed( $permission );
1500                 } else {
1501                         return true;
1502                 }
1503         }
1504
1505         /**
1506          * Get rev_timestamp from rev_id, without loading the rest of the row
1507          *
1508          * @param $title Title
1509          * @param $id Integer
1510          * @return String
1511          */
1512         static function getTimestampFromId( $title, $id ) {
1513                 $dbr = wfGetDB( DB_SLAVE );
1514                 // Casting fix for DB2
1515                 if ( $id == '' ) {
1516                         $id = 0;
1517                 }
1518                 $conds = array( 'rev_id' => $id );
1519                 $conds['rev_page'] = $title->getArticleID();
1520                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1521                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1522                         # Not in slave, try master
1523                         $dbw = wfGetDB( DB_MASTER );
1524                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1525                 }
1526                 return wfTimestamp( TS_MW, $timestamp );
1527         }
1528
1529         /**
1530          * Get count of revisions per page...not very efficient
1531          *
1532          * @param $db DatabaseBase
1533          * @param $id Integer: page id
1534          * @return Integer
1535          */
1536         static function countByPageId( $db, $id ) {
1537                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1538                         array( 'rev_page' => $id ), __METHOD__ );
1539                 if( $row ) {
1540                         return $row->revCount;
1541                 }
1542                 return 0;
1543         }
1544
1545         /**
1546          * Get count of revisions per page...not very efficient
1547          *
1548          * @param $db DatabaseBase
1549          * @param $title Title
1550          * @return Integer
1551          */
1552         static function countByTitle( $db, $title ) {
1553                 $id = $title->getArticleID();
1554                 if( $id ) {
1555                         return Revision::countByPageId( $db, $id );
1556                 }
1557                 return 0;
1558         }
1559 }