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