includes/Revision.php

   1 <?php
   2 /**
   3  * @todo document
   4  * @file
   5  */
   6
   7 /**
   8  * @todo document
   9  */
  10 class Revision {
  11         const DELETED_TEXT = 1;
  12         const DELETED_COMMENT = 2;
  13         const DELETED_USER = 4;
  14         const DELETED_RESTRICTED = 8;
  15
  16         // Audience options for Revision::getText()
  17         const FOR_PUBLIC = 1;
  18         const FOR_THIS_USER = 2;
  19         const RAW = 3;
  20
  21         /**
  22          * Load a page revision from a given revision ID number.
  23          * Returns null if no such revision can be found.
  24          *
  25          * @param int $id
  26          * @access public
  27          * @static
  28          */
  29         public static function newFromId( $id ) {
  30                 return Revision::newFromConds(
  31                         array( 'page_id=rev_page',
  32                                'rev_id' => intval( $id ) ) );
  33         }
  34
  35         /**
  36          * Load either the current, or a specified, revision
  37          * that's attached to a given title. If not attached
  38          * to that title, will return null.
  39          *
  40          * @param Title $title
  41          * @param int $id
  42          * @return Revision
  43          */
  44         public static function newFromTitle( $title, $id = 0 ) {
  45                 $conds = array(
  46                         'page_namespace' => $title->getNamespace(),
  47                         'page_title' => $title->getDBkey()
  48                 );
  49                 if ( $id ) {
  50                         // Use the specified ID
  51                         $conds['rev_id'] = $id;
  52                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  53                         // Get the latest revision ID from the master
  54                         $dbw = wfGetDB( DB_MASTER );
  55                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  56                         if ( $latest === false ) {
  57                                 // Page does not exist
  58                                 return null;
  59                         }
  60                         $conds['rev_id'] = $latest;
  61                 } else {
  62                         // Use a join to get the latest revision
  63                         $conds[] = 'rev_id=page_latest';
  64                 }
  65                 $conds[] = 'page_id=rev_page';
  66                 return Revision::newFromConds( $conds );
  67         }
  68
  69         /**
  70          * Make a fake revision object from an archive table row. This is queried
  71          * for permissions or even inserted (as in Special:Undelete)
  72          * @fixme: should be a subclass for RevisionDelete. [TS]
  73          */
  74         public static function newFromArchiveRow( $row, $overrides = array() ) {
  75                 $attribs = $overrides + array(
  76                         'page'       => isset( $row->page_id ) ? $row->page_id : null,
  77                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
  78                         'comment'    => $row->ar_comment,
  79                         'user'       => $row->ar_user,
  80                         'user_text'  => $row->ar_user_text,
  81                         'timestamp'  => $row->ar_timestamp,
  82                         'minor_edit' => $row->ar_minor_edit,
  83                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
  84                         'deleted'    => $row->ar_deleted,
  85                         'len'        => $row->ar_len);
  86                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
  87                         // Pre-1.5 ar_text row
  88                         $attribs['text'] = $row->ar_text;
  89                 }
  90                 return new self( $attribs );
  91         }
  92
  93         /**
  94          * Load a page revision from a given revision ID number.
  95          * Returns null if no such revision can be found.
  96          *
  97          * @param Database $db
  98          * @param int $id
  99          * @access public
 100          * @static
 101          */
 102         public static function loadFromId( $db, $id ) {
 103                 return Revision::loadFromConds( $db,
 104                         array( 'page_id=rev_page',
 105                                'rev_id' => intval( $id ) ) );
 106         }
 107
 108         /**
 109          * Load either the current, or a specified, revision
 110          * that's attached to a given page. If not attached
 111          * to that page, will return null.
 112          *
 113          * @param Database $db
 114          * @param int $pageid
 115          * @param int $id
 116          * @return Revision
 117          * @access public
 118          * @static
 119          */
 120         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 121                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
 122                 if( $id ) {
 123                         $conds['rev_id']=intval($id);
 124                 } else {
 125                         $conds[]='rev_id=page_latest';
 126                 }
 127                 return Revision::loadFromConds( $db, $conds );
 128         }
 129
 130         /**
 131          * Load either the current, or a specified, revision
 132          * that's attached to a given page. If not attached
 133          * to that page, will return null.
 134          *
 135          * @param Database $db
 136          * @param Title $title
 137          * @param int $id
 138          * @return Revision
 139          * @access public
 140          * @static
 141          */
 142         public static function loadFromTitle( $db, $title, $id = 0 ) {
 143                 if( $id ) {
 144                         $matchId = intval( $id );
 145                 } else {
 146                         $matchId = 'page_latest';
 147                 }
 148                 return Revision::loadFromConds(
 149                         $db,
 150                         array( "rev_id=$matchId",
 151                                'page_id=rev_page',
 152                                'page_namespace' => $title->getNamespace(),
 153                                'page_title'     => $title->getDBkey() ) );
 154         }
 155
 156         /**
 157          * Load the revision for the given title with the given timestamp.
 158          * WARNING: Timestamps may in some circumstances not be unique,
 159          * so this isn't the best key to use.
 160          *
 161          * @param Database $db
 162          * @param Title $title
 163          * @param string $timestamp
 164          * @return Revision
 165          * @access public
 166          * @static
 167          */
 168         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 169                 return Revision::loadFromConds(
 170                         $db,
 171                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 172                                'page_id=rev_page',
 173                                'page_namespace' => $title->getNamespace(),
 174                                'page_title'     => $title->getDBkey() ) );
 175         }
 176
 177         /**
 178          * Given a set of conditions, fetch a revision.
 179          *
 180          * @param array $conditions
 181          * @return Revision
 182          * @access private
 183          * @static
 184          */
 185         private static function newFromConds( $conditions ) {
 186                 $db = wfGetDB( DB_SLAVE );
 187                 $row = Revision::loadFromConds( $db, $conditions );
 188                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 189                         $dbw = wfGetDB( DB_MASTER );
 190                         $row = Revision::loadFromConds( $dbw, $conditions );
 191                 }
 192                 return $row;
 193         }
 194
 195         /**
 196          * Given a set of conditions, fetch a revision from
 197          * the given database connection.
 198          *
 199          * @param Database $db
 200          * @param array $conditions
 201          * @return Revision
 202          * @access private
 203          * @static
 204          */
 205         private static function loadFromConds( $db, $conditions ) {
 206                 $res = Revision::fetchFromConds( $db, $conditions );
 207                 if( $res ) {
 208                         $row = $res->fetchObject();
 209                         $res->free();
 210                         if( $row ) {
 211                                 $ret = new Revision( $row );
 212                                 return $ret;
 213                         }
 214                 }
 215                 $ret = null;
 216                 return $ret;
 217         }
 218
 219         /**
 220          * Return a wrapper for a series of database rows to
 221          * fetch all of a given page's revisions in turn.
 222          * Each row can be fed to the constructor to get objects.
 223          *
 224          * @param Title $title
 225          * @return ResultWrapper
 226          * @access public
 227          * @static
 228          */
 229         public static function fetchAllRevisions( $title ) {
 230                 return Revision::fetchFromConds(
 231                         wfGetDB( DB_SLAVE ),
 232                         array( 'page_namespace' => $title->getNamespace(),
 233                                'page_title'     => $title->getDBkey(),
 234                                'page_id=rev_page' ) );
 235         }
 236
 237         /**
 238          * Return a wrapper for a series of database rows to
 239          * fetch all of a given page's revisions in turn.
 240          * Each row can be fed to the constructor to get objects.
 241          *
 242          * @param Title $title
 243          * @return ResultWrapper
 244          * @access public
 245          * @static
 246          */
 247         public static function fetchRevision( $title ) {
 248                 return Revision::fetchFromConds(
 249                         wfGetDB( DB_SLAVE ),
 250                         array( 'rev_id=page_latest',
 251                                'page_namespace' => $title->getNamespace(),
 252                                'page_title'     => $title->getDBkey(),
 253                                'page_id=rev_page' ) );
 254         }
 255
 256         /**
 257          * Given a set of conditions, return a ResultWrapper
 258          * which will return matching database rows with the
 259          * fields necessary to build Revision objects.
 260          *
 261          * @param Database $db
 262          * @param array $conditions
 263          * @return ResultWrapper
 264          * @access private
 265          * @static
 266          */
 267         private static function fetchFromConds( $db, $conditions ) {
 268                 $fields = self::selectFields();
 269                 $fields[] = 'page_namespace';
 270                 $fields[] = 'page_title';
 271                 $fields[] = 'page_latest';
 272                 $res = $db->select(
 273                         array( 'page', 'revision' ),
 274                         $fields,
 275                         $conditions,
 276                         __METHOD__,
 277                         array( 'LIMIT' => 1 ) );
 278                 $ret = $db->resultObject( $res );
 279                 return $ret;
 280         }
 281
 282         /**
 283          * Return the list of revision fields that should be selected to create
 284          * a new revision.
 285          */
 286         static function selectFields() {
 287                 return array(
 288                         'rev_id',
 289                         'rev_page',
 290                         'rev_text_id',
 291                         'rev_timestamp',
 292                         'rev_comment',
 293                         'rev_user_text,'.
 294                         'rev_user',
 295                         'rev_minor_edit',
 296                         'rev_deleted',
 297                         'rev_len',
 298                         'rev_parent_id'
 299                 );
 300         }
 301
 302         /**
 303          * Return the list of text fields that should be selected to read the
 304          * revision text
 305          */
 306         static function selectTextFields() {
 307                 return array(
 308                         'old_text',
 309                         'old_flags'
 310                 );
 311         }
 312         /**
 313          * Return the list of page fields that should be selected from page table
 314          */
 315         static function selectPageFields() {
 316                 return array(
 317                         'page_namespace',
 318                         'page_title',
 319                         'page_latest'
 320                 );
 321         }
 322
 323         /**
 324          * @param object $row
 325          * @access private
 326          */
 327         function Revision( $row ) {
 328                 if( is_object( $row ) ) {
 329                         $this->mId        = intval( $row->rev_id );
 330                         $this->mPage      = intval( $row->rev_page );
 331                         $this->mTextId    = intval( $row->rev_text_id );
 332                         $this->mComment   =         $row->rev_comment;
 333                         $this->mUserText  =         $row->rev_user_text;
 334                         $this->mUser      = intval( $row->rev_user );
 335                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 336                         $this->mTimestamp =         $row->rev_timestamp;
 337                         $this->mDeleted   = intval( $row->rev_deleted );
 338
 339                         if( !isset( $row->rev_parent_id ) )
 340                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 341                         else
 342                                 $this->mParentId  = intval( $row->rev_parent_id );
 343
 344                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 345                                 $this->mSize = null;
 346                         else
 347                                 $this->mSize = intval( $row->rev_len );
 348
 349                         if( isset( $row->page_latest ) ) {
 350                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 351                                 $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 352                                 $this->mTitle->resetArticleID( $this->mPage );
 353                         } else {
 354                                 $this->mCurrent = false;
 355                                 $this->mTitle = null;
 356                         }
 357
 358                         // Lazy extraction...
 359                         $this->mText      = null;
 360                         if( isset( $row->old_text ) ) {
 361                                 $this->mTextRow = $row;
 362                         } else {
 363                                 // 'text' table row entry will be lazy-loaded
 364                                 $this->mTextRow = null;
 365                         }
 366                 } elseif( is_array( $row ) ) {
 367                         // Build a new revision to be saved...
 368                         global $wgUser;
 369
 370                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 371                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 372                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 373                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 374                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 375                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 376                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 377                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 378                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 379                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 380
 381                         // Enforce spacing trimming on supplied text
 382                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 383                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 384                         $this->mTextRow   = null;
 385
 386                         $this->mTitle     = null; # Load on demand if needed
 387                         $this->mCurrent   = false;
 388                         # If we still have no len_size, see it we have the text to figure it out
 389                         if ( !$this->mSize )
 390                                 $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 391                 } else {
 392                         throw new MWException( 'Revision constructor passed invalid row format.' );
 393                 }
 394                 $this->mUnpatrolled = NULL;
 395         }
 396
 397         /**#@+
 398          * @access public
 399          */
 400
 401         /**
 402          * Get revision ID
 403          * @return int
 404          */
 405         public function getId() {
 406                 return $this->mId;
 407         }
 408
 409         /**
 410          * Get text row ID
 411          * @return int
 412          */
 413         public function getTextId() {
 414                 return $this->mTextId;
 415         }
 416
 417         /**
 418          * Get parent revision ID (the original previous page revision)
 419          * @return int
 420          */
 421         public function getParentId() {
 422                 return $this->mParentId;
 423         }
 424
 425         /**
 426          * Returns the length of the text in this revision, or null if unknown.
 427          * @return int
 428          */
 429         public function getSize() {
 430                 return $this->mSize;
 431         }
 432
 433         /**
 434          * Returns the title of the page associated with this entry.
 435          * @return Title
 436          */
 437         public function getTitle() {
 438                 if( isset( $this->mTitle ) ) {
 439                         return $this->mTitle;
 440                 }
 441                 $dbr = wfGetDB( DB_SLAVE );
 442                 $row = $dbr->selectRow(
 443                         array( 'page', 'revision' ),
 444                         array( 'page_namespace', 'page_title' ),
 445                         array( 'page_id=rev_page',
 446                                'rev_id' => $this->mId ),
 447                         'Revision::getTitle' );
 448                 if( $row ) {
 449                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 450                                                           $row->page_title );
 451                 }
 452                 return $this->mTitle;
 453         }
 454
 455         /**
 456          * Set the title of the revision
 457          * @param Title $title
 458          */
 459         public function setTitle( $title ) {
 460                 $this->mTitle = $title;
 461         }
 462
 463         /**
 464          * Get the page ID
 465          * @return int
 466          */
 467         public function getPage() {
 468                 return $this->mPage;
 469         }
 470
 471         /**
 472          * Fetch revision's user id if it's available to the specified audience.
 473          * If the specified audience does not have access to it, zero will be
 474          * returned.
 475          *
 476          * @param integer $audience One of:
 477          *      Revision::FOR_PUBLIC       to be displayed to all users
 478          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 479          *      Revision::RAW              get the ID regardless of permissions
 480          *
 481          *
 482          * @return int
 483          */
 484         public function getUser( $audience = self::FOR_PUBLIC ) {
 485                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 486                         return 0;
 487                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 488                         return 0;
 489                 } else {
 490                         return $this->mUser;
 491                 }
 492         }
 493
 494         /**
 495          * Fetch revision's user id without regard for the current user's permissions
 496          * @return string
 497          */
 498         public function getRawUser() {
 499                 return $this->mUser;
 500         }
 501
 502         /**
 503          * Fetch revision's username if it's available to the specified audience.
 504          * If the specified audience does not have access to the username, an
 505          * empty string will be returned.
 506          *
 507          * @param integer $audience One of:
 508          *      Revision::FOR_PUBLIC       to be displayed to all users
 509          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 510          *      Revision::RAW              get the text regardless of permissions
 511          *
 512          * @return string
 513          */
 514         public function getUserText( $audience = self::FOR_PUBLIC ) {
 515                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 516                         return "";
 517                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 518                         return "";
 519                 } else {
 520                         return $this->mUserText;
 521                 }
 522         }
 523
 524         /**
 525          * Fetch revision's username without regard for view restrictions
 526          * @return string
 527          */
 528         public function getRawUserText() {
 529                 return $this->mUserText;
 530         }
 531
 532         /**
 533          * Fetch revision comment if it's available to the specified audience.
 534          * If the specified audience does not have access to the comment, an
 535          * empty string will be returned.
 536          *
 537          * @param integer $audience One of:
 538          *      Revision::FOR_PUBLIC       to be displayed to all users
 539          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 540          *      Revision::RAW              get the text regardless of permissions
 541          *
 542          * @return string
 543          */
 544         function getComment( $audience = self::FOR_PUBLIC ) {
 545                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 546                         return "";
 547                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 548                         return "";
 549                 } else {
 550                         return $this->mComment;
 551                 }
 552         }
 553
 554         /**
 555          * Fetch revision comment without regard for the current user's permissions
 556          * @return string
 557          */
 558         public function getRawComment() {
 559                 return $this->mComment;
 560         }
 561
 562         /**
 563          * @return bool
 564          */
 565         public function isMinor() {
 566                 return (bool)$this->mMinorEdit;
 567         }
 568
 569         /**
 570          * @return int rcid of the unpatrolled row, zero if there isn't one
 571          */
 572         public function isUnpatrolled() {
 573                 if( $this->mUnpatrolled !== NULL ) {
 574                         return $this->mUnpatrolled;
 575                 }
 576                 $dbr = wfGetDB( DB_SLAVE );
 577                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 578                         'rc_id',
 579                         array( // Add redundant user,timestamp condition so we can use the existing index
 580                                 'rc_user_text'  => $this->getRawUserText(),
 581                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 582                                 'rc_this_oldid' => $this->getId(),
 583                                 'rc_patrolled'  => 0
 584                         ),
 585                         __METHOD__
 586                 );
 587                 return (int)$this->mUnpatrolled;
 588         }
 589
 590         /**
 591          * int $field one of DELETED_* bitfield constants
 592          * @return bool
 593          */
 594         public function isDeleted( $field ) {
 595                 return ($this->mDeleted & $field) == $field;
 596         }
 597
 598         /**
 599          * Get the deletion bitfield of the revision
 600          */
 601         public function getVisibility() {
 602                 return (int)$this->mDeleted;
 603         }
 604
 605         /**
 606          * Fetch revision text if it's available to the specified audience.
 607          * If the specified audience does not have the ability to view this
 608          * revision, an empty string will be returned.
 609          *
 610          * @param integer $audience One of:
 611          *      Revision::FOR_PUBLIC       to be displayed to all users
 612          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 613          *      Revision::RAW              get the text regardless of permissions
 614          *
 615          *
 616          * @return string
 617          */
 618         public function getText( $audience = self::FOR_PUBLIC ) {
 619                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 620                         return "";
 621                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 622                         return "";
 623                 } else {
 624                         return $this->getRawText();
 625                 }
 626         }
 627
 628         /**
 629          * Alias for getText(Revision::FOR_THIS_USER)
 630          */
 631         public function revText() {
 632                 return $this->getText( self::FOR_THIS_USER );
 633         }
 634
 635         /**
 636          * Fetch revision text without regard for view restrictions
 637          * @return string
 638          */
 639         public function getRawText() {
 640                 if( is_null( $this->mText ) ) {
 641                         // Revision text is immutable. Load on demand:
 642                         $this->mText = $this->loadText();
 643                 }
 644                 return $this->mText;
 645         }
 646
 647         /**
 648          * @return string
 649          */
 650         public function getTimestamp() {
 651                 return wfTimestamp(TS_MW, $this->mTimestamp);
 652         }
 653
 654         /**
 655          * @return bool
 656          */
 657         public function isCurrent() {
 658                 return $this->mCurrent;
 659         }
 660
 661         /**
 662          * Get previous revision for this title
 663          * @return Revision
 664          */
 665         public function getPrevious() {
 666                 if( $this->getTitle() ) {
 667                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 668                         if( $prev ) {
 669                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 670                         }
 671                 }
 672                 return null;
 673         }
 674
 675         /**
 676          * @return Revision
 677          */
 678         public function getNext() {
 679                 if( $this->getTitle() ) {
 680                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 681                         if ( $next ) {
 682                                 return Revision::newFromTitle( $this->getTitle(), $next );
 683                         }
 684                 }
 685                 return null;
 686         }
 687
 688         /**
 689          * Get previous revision Id for this page_id
 690          * This is used to populate rev_parent_id on save
 691          * @param Database $db
 692          * @return int
 693          */
 694         private function getPreviousRevisionId( $db ) {
 695                 if( is_null($this->mPage) ) {
 696                         return 0;
 697                 }
 698                 # Use page_latest if ID is not given
 699                 if( !$this->mId ) {
 700                         $prevId = $db->selectField( 'page', 'page_latest',
 701                                 array( 'page_id' => $this->mPage ),
 702                                 __METHOD__ );
 703                 } else {
 704                         $prevId = $db->selectField( 'revision', 'rev_id',
 705                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 706                                 __METHOD__,
 707                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 708                 }
 709                 return intval($prevId);
 710         }
 711
 712         /**
 713           * Get revision text associated with an old or archive row
 714           * $row is usually an object from wfFetchRow(), both the flags and the text
 715           * field must be included
 716           *
 717           * @param object $row The text data
 718           * @param string $prefix table prefix (default 'old_')
 719           * @return string $text|false the text requested
 720           */
 721         public static function getRevisionText( $row, $prefix = 'old_' ) {
 722                 wfProfileIn( __METHOD__ );
 723
 724                 # Get data
 725                 $textField = $prefix . 'text';
 726                 $flagsField = $prefix . 'flags';
 727
 728                 if( isset( $row->$flagsField ) ) {
 729                         $flags = explode( ',', $row->$flagsField );
 730                 } else {
 731                         $flags = array();
 732                 }
 733
 734                 if( isset( $row->$textField ) ) {
 735                         $text = $row->$textField;
 736                 } else {
 737                         wfProfileOut( __METHOD__ );
 738                         return false;
 739                 }
 740
 741                 # Use external methods for external objects, text in table is URL-only then
 742                 if ( in_array( 'external', $flags ) ) {
 743                         $url=$text;
 744                         @list(/* $proto */,$path)=explode('://',$url,2);
 745                         if ($path=="") {
 746                                 wfProfileOut( __METHOD__ );
 747                                 return false;
 748                         }
 749                         $text=ExternalStore::fetchFromURL($url);
 750                 }
 751
 752                 // If the text was fetched without an error, convert it
 753                 if ( $text !== false ) {
 754                         if( in_array( 'gzip', $flags ) ) {
 755                                 # Deal with optional compression of archived pages.
 756                                 # This can be done periodically via maintenance/compressOld.php, and
 757                                 # as pages are saved if $wgCompressRevisions is set.
 758                                 $text = gzinflate( $text );
 759                         }
 760
 761                         if( in_array( 'object', $flags ) ) {
 762                                 # Generic compressed storage
 763                                 $obj = unserialize( $text );
 764                                 if ( !is_object( $obj ) ) {
 765                                         // Invalid object
 766                                         wfProfileOut( __METHOD__ );
 767                                         return false;
 768                                 }
 769                                 $text = $obj->getText();
 770                         }
 771
 772                         global $wgLegacyEncoding;
 773                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) ) {
 774                                 # Old revisions kept around in a legacy encoding?
 775                                 # Upconvert on demand.
 776                                 # ("utf8" checked for compatibility with some broken
 777                                 #  conversion scripts 2008-12-30)
 778                                 global $wgInputEncoding, $wgContLang;
 779                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 780                         }
 781                 }
 782                 wfProfileOut( __METHOD__ );
 783                 return $text;
 784         }
 785
 786         /**
 787          * If $wgCompressRevisions is enabled, we will compress data.
 788          * The input string is modified in place.
 789          * Return value is the flags field: contains 'gzip' if the
 790          * data is compressed, and 'utf-8' if we're saving in UTF-8
 791          * mode.
 792          *
 793          * @param mixed $text reference to a text
 794          * @return string
 795          */
 796         public static function compressRevisionText( &$text ) {
 797                 global $wgCompressRevisions;
 798                 $flags = array();
 799
 800                 # Revisions not marked this way will be converted
 801                 # on load if $wgLegacyCharset is set in the future.
 802                 $flags[] = 'utf-8';
 803
 804                 if( $wgCompressRevisions ) {
 805                         if( function_exists( 'gzdeflate' ) ) {
 806                                 $text = gzdeflate( $text );
 807                                 $flags[] = 'gzip';
 808                         } else {
 809                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 810                         }
 811                 }
 812                 return implode( ',', $flags );
 813         }
 814
 815         /**
 816          * Insert a new revision into the database, returning the new revision ID
 817          * number on success and dies horribly on failure.
 818          *
 819          * @param Database $dbw
 820          * @return int
 821          */
 822         public function insertOn( $dbw ) {
 823                 global $wgDefaultExternalStore;
 824
 825                 wfProfileIn( __METHOD__ );
 826
 827                 $data = $this->mText;
 828                 $flags = Revision::compressRevisionText( $data );
 829
 830                 # Write to external storage if required
 831                 if( $wgDefaultExternalStore ) {
 832                         // Store and get the URL
 833                         $data = ExternalStore::insertToDefault( $data );
 834                         if( !$data ) {
 835                                 throw new MWException( "Unable to store text to external storage" );
 836                         }
 837                         if( $flags ) {
 838                                 $flags .= ',';
 839                         }
 840                         $flags .= 'external';
 841                 }
 842
 843                 # Record the text (or external storage URL) to the text table
 844                 if( !isset( $this->mTextId ) ) {
 845                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 846                         $dbw->insert( 'text',
 847                                 array(
 848                                         'old_id'    => $old_id,
 849                                         'old_text'  => $data,
 850                                         'old_flags' => $flags,
 851                                 ), __METHOD__
 852                         );
 853                         $this->mTextId = $dbw->insertId();
 854                 }
 855
 856                 # Record the edit in revisions
 857                 $rev_id = isset( $this->mId )
 858                         ? $this->mId
 859                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 860                 $dbw->insert( 'revision',
 861                         array(
 862                                 'rev_id'         => $rev_id,
 863                                 'rev_page'       => $this->mPage,
 864                                 'rev_text_id'    => $this->mTextId,
 865                                 'rev_comment'    => $this->mComment,
 866                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 867                                 'rev_user'       => $this->mUser,
 868                                 'rev_user_text'  => $this->mUserText,
 869                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 870                                 'rev_deleted'    => $this->mDeleted,
 871                                 'rev_len'            => $this->mSize,
 872                                 'rev_parent_id'  => is_null($this->mParentId) ?
 873                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 874                         ), __METHOD__
 875                 );
 876
 877                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 878
 879                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 880
 881                 wfProfileOut( __METHOD__ );
 882                 return $this->mId;
 883         }
 884
 885         /**
 886          * Lazy-load the revision's text.
 887          * Currently hardcoded to the 'text' table storage engine.
 888          *
 889          * @return string
 890          */
 891         protected function loadText() {
 892                 wfProfileIn( __METHOD__ );
 893
 894                 // Caching may be beneficial for massive use of external storage
 895                 global $wgRevisionCacheExpiry, $wgMemc;
 896                 $textId = $this->getTextId();
 897                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 898                 if( $wgRevisionCacheExpiry ) {
 899                         $text = $wgMemc->get( $key );
 900                         if( is_string( $text ) ) {
 901                                 wfDebug( __METHOD__. ": got id $textId from cache\n" );
 902                                 wfProfileOut( __METHOD__ );
 903                                 return $text;
 904                         }
 905                 }
 906
 907                 // If we kept data for lazy extraction, use it now...
 908                 if ( isset( $this->mTextRow ) ) {
 909                         $row = $this->mTextRow;
 910                         $this->mTextRow = null;
 911                 } else {
 912                         $row = null;
 913                 }
 914
 915                 if( !$row ) {
 916                         // Text data is immutable; check slaves first.
 917                         $dbr = wfGetDB( DB_SLAVE );
 918                         $row = $dbr->selectRow( 'text',
 919                                 array( 'old_text', 'old_flags' ),
 920                                 array( 'old_id' => $this->getTextId() ),
 921                                 __METHOD__ );
 922                 }
 923
 924                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 925                         // Possible slave lag!
 926                         $dbw = wfGetDB( DB_MASTER );
 927                         $row = $dbw->selectRow( 'text',
 928                                 array( 'old_text', 'old_flags' ),
 929                                 array( 'old_id' => $this->getTextId() ),
 930                                 __METHOD__ );
 931                 }
 932
 933                 $text = self::getRevisionText( $row );
 934
 935                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 936                 if( $wgRevisionCacheExpiry && $text !== false ) {
 937                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 938                 }
 939
 940                 wfProfileOut( __METHOD__ );
 941
 942                 return $text;
 943         }
 944
 945         /**
 946          * Create a new null-revision for insertion into a page's
 947          * history. This will not re-save the text, but simply refer
 948          * to the text from the previous version.
 949          *
 950          * Such revisions can for instance identify page rename
 951          * operations and other such meta-modifications.
 952          *
 953          * @param Database $dbw
 954          * @param int      $pageId ID number of the page to read from
 955          * @param string   $summary
 956          * @param bool     $minor
 957          * @return Revision
 958          */
 959         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 960                 wfProfileIn( __METHOD__ );
 961
 962                 $current = $dbw->selectRow(
 963                         array( 'page', 'revision' ),
 964                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 965                         array(
 966                                 'page_id' => $pageId,
 967                                 'page_latest=rev_id',
 968                                 ),
 969                         __METHOD__ );
 970
 971                 if( $current ) {
 972                         $revision = new Revision( array(
 973                                 'page'       => $pageId,
 974                                 'comment'    => $summary,
 975                                 'minor_edit' => $minor,
 976                                 'text_id'    => $current->rev_text_id,
 977                                 'parent_id'  => $current->page_latest,
 978                                 'len'        => $current->rev_len
 979                                 ) );
 980                 } else {
 981                         $revision = null;
 982                 }
 983
 984                 wfProfileOut( __METHOD__ );
 985                 return $revision;
 986         }
 987
 988         /**
 989          * Determine if the current user is allowed to view a particular
 990          * field of this revision, if it's marked as deleted.
 991          * @param int $field one of self::DELETED_TEXT,
 992          *                          self::DELETED_COMMENT,
 993          *                          self::DELETED_USER
 994          * @return bool
 995          */
 996         public function userCan( $field ) {
 997                 if( ( $this->mDeleted & $field ) == $field ) {
 998                         global $wgUser;
 999                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
1000                                 ? 'suppressrevision'
1001                                 : 'deleterevision';
1002                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
1003                         return $wgUser->isAllowed( $permission );
1004                 } else {
1005                         return true;
1006                 }
1007         }
1008
1009
1010         /**
1011          * Get rev_timestamp from rev_id, without loading the rest of the row
1012          * @param Title $title
1013          * @param integer $id
1014          */
1015         static function getTimestampFromId( $title, $id ) {
1016                 $dbr = wfGetDB( DB_SLAVE );
1017                 // Casting fix for DB2
1018                 if ($id == '') {
1019                         $id = 0;
1020                 }
1021                 $conds = array( 'rev_id' => $id );
1022                 $conds['rev_page'] = $title->getArticleId();
1023                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1024                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1025                         # Not in slave, try master
1026                         $dbw = wfGetDB( DB_MASTER );
1027                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1028                 }
1029                 return wfTimestamp( TS_MW, $timestamp );
1030         }
1031
1032         /**
1033          * Get count of revisions per page...not very efficient
1034          * @param Database $db
1035          * @param int $id, page id
1036          */
1037         static function countByPageId( $db, $id ) {
1038                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1039                         array( 'rev_page' => $id ), __METHOD__ );
1040                 if( $row ) {
1041                         return $row->revCount;
1042                 }
1043                 return 0;
1044         }
1045
1046         /**
1047          * Get count of revisions per page...not very efficient
1048          * @param Database $db
1049          * @param Title $title
1050          */
1051         static function countByTitle( $db, $title ) {
1052                 $id = $title->getArticleId();
1053                 if( $id ) {
1054                         return Revision::countByPageId( $db, $id );
1055                 }
1056                 return 0;
1057         }
1058 }
1059
1060 /**
1061  * Aliases for backwards compatibility with 1.6
1062  */
1063 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1064 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1065 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1066 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );