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