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) == $field;
 546         }
 547
 548         /**
 549          * Get the deletion bitfield of the revision
 550          */
 551         public function getVisibility() {
 552                 return (int)$this->mDeleted;
 553         }
 554
 555         /**
 556          * Fetch revision text if it's available to the specified audience.
 557          * If the specified audience does not have the ability to view this
 558          * revision, an empty string will be returned.
 559          *
 560          * @param integer $audience One of:
 561          *      Revision::FOR_PUBLIC       to be displayed to all users
 562          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 563          *      Revision::RAW              get the text regardless of permissions
 564          *
 565          *
 566          * @return string
 567          */
 568         public function getText( $audience = self::FOR_PUBLIC ) {
 569                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 570                         return "";
 571                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 572                         return "";
 573                 } else {
 574                         return $this->getRawText();
 575                 }
 576         }
 577
 578         /**
 579          * Alias for getText(Revision::FOR_THIS_USER)
 580          */
 581         public function revText() {
 582                 return $this->getText( self::FOR_THIS_USER );
 583         }
 584
 585         /**
 586          * Fetch revision text without regard for view restrictions
 587          * @return string
 588          */
 589         public function getRawText() {
 590                 if( is_null( $this->mText ) ) {
 591                         // Revision text is immutable. Load on demand:
 592                         $this->mText = $this->loadText();
 593                 }
 594                 return $this->mText;
 595         }
 596
 597         /**
 598          * @return string
 599          */
 600         public function getTimestamp() {
 601                 return wfTimestamp(TS_MW, $this->mTimestamp);
 602         }
 603
 604         /**
 605          * @return bool
 606          */
 607         public function isCurrent() {
 608                 return $this->mCurrent;
 609         }
 610
 611         /**
 612          * Get previous revision for this title
 613          * @return Revision
 614          */
 615         public function getPrevious() {
 616                 if( $this->getTitle() ) {
 617                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 618                         if( $prev ) {
 619                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 620                         }
 621                 }
 622                 return null;
 623         }
 624
 625         /**
 626          * @return Revision
 627          */
 628         public function getNext() {
 629                 if( $this->getTitle() ) {
 630                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 631                         if ( $next ) {
 632                                 return Revision::newFromTitle( $this->getTitle(), $next );
 633                         }
 634                 }
 635                 return null;
 636         }
 637
 638         /**
 639          * Get previous revision Id for this page_id
 640          * This is used to populate rev_parent_id on save
 641          * @param Database $db
 642          * @return int
 643          */
 644         private function getPreviousRevisionId( $db ) {
 645                 if( is_null($this->mPage) ) {
 646                         return 0;
 647                 }
 648                 # Use page_latest if ID is not given
 649                 if( !$this->mId ) {
 650                         $prevId = $db->selectField( 'page', 'page_latest',
 651                                 array( 'page_id' => $this->mPage ),
 652                                 __METHOD__ );
 653                 } else {
 654                         $prevId = $db->selectField( 'revision', 'rev_id',
 655                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 656                                 __METHOD__,
 657                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 658                 }
 659                 return intval($prevId);
 660         }
 661
 662         /**
 663           * Get revision text associated with an old or archive row
 664           * $row is usually an object from wfFetchRow(), both the flags and the text
 665           * field must be included
 666           *
 667           * @param object $row The text data
 668           * @param string $prefix table prefix (default 'old_')
 669           * @return string $text|false the text requested
 670           */
 671         public static function getRevisionText( $row, $prefix = 'old_' ) {
 672                 wfProfileIn( __METHOD__ );
 673
 674                 # Get data
 675                 $textField = $prefix . 'text';
 676                 $flagsField = $prefix . 'flags';
 677
 678                 if( isset( $row->$flagsField ) ) {
 679                         $flags = explode( ',', $row->$flagsField );
 680                 } else {
 681                         $flags = array();
 682                 }
 683
 684                 if( isset( $row->$textField ) ) {
 685                         $text = $row->$textField;
 686                 } else {
 687                         wfProfileOut( __METHOD__ );
 688                         return false;
 689                 }
 690
 691                 # Use external methods for external objects, text in table is URL-only then
 692                 if ( in_array( 'external', $flags ) ) {
 693                         $url=$text;
 694                         @list(/* $proto */,$path)=explode('://',$url,2);
 695                         if ($path=="") {
 696                                 wfProfileOut( __METHOD__ );
 697                                 return false;
 698                         }
 699                         $text=ExternalStore::fetchFromURL($url);
 700                 }
 701
 702                 // If the text was fetched without an error, convert it
 703                 if ( $text !== false ) {
 704                         if( in_array( 'gzip', $flags ) ) {
 705                                 # Deal with optional compression of archived pages.
 706                                 # This can be done periodically via maintenance/compressOld.php, and
 707                                 # as pages are saved if $wgCompressRevisions is set.
 708                                 $text = gzinflate( $text );
 709                         }
 710
 711                         if( in_array( 'object', $flags ) ) {
 712                                 # Generic compressed storage
 713                                 $obj = unserialize( $text );
 714                                 if ( !is_object( $obj ) ) {
 715                                         // Invalid object
 716                                         wfProfileOut( __METHOD__ );
 717                                         return false;
 718                                 }
 719                                 $text = $obj->getText();
 720                         }
 721
 722                         global $wgLegacyEncoding;
 723                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 724                                 # Old revisions kept around in a legacy encoding?
 725                                 # Upconvert on demand.
 726                                 global $wgInputEncoding, $wgContLang;
 727                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 728                         }
 729                 }
 730                 wfProfileOut( __METHOD__ );
 731                 return $text;
 732         }
 733
 734         /**
 735          * If $wgCompressRevisions is enabled, we will compress data.
 736          * The input string is modified in place.
 737          * Return value is the flags field: contains 'gzip' if the
 738          * data is compressed, and 'utf-8' if we're saving in UTF-8
 739          * mode.
 740          *
 741          * @param mixed $text reference to a text
 742          * @return string
 743          */
 744         public static function compressRevisionText( &$text ) {
 745                 global $wgCompressRevisions;
 746                 $flags = array();
 747
 748                 # Revisions not marked this way will be converted
 749                 # on load if $wgLegacyCharset is set in the future.
 750                 $flags[] = 'utf-8';
 751
 752                 if( $wgCompressRevisions ) {
 753                         if( function_exists( 'gzdeflate' ) ) {
 754                                 $text = gzdeflate( $text );
 755                                 $flags[] = 'gzip';
 756                         } else {
 757                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 758                         }
 759                 }
 760                 return implode( ',', $flags );
 761         }
 762
 763         /**
 764          * Insert a new revision into the database, returning the new revision ID
 765          * number on success and dies horribly on failure.
 766          *
 767          * @param Database $dbw
 768          * @return int
 769          */
 770         public function insertOn( $dbw ) {
 771                 global $wgDefaultExternalStore;
 772
 773                 wfProfileIn( __METHOD__ );
 774
 775                 $data = $this->mText;
 776                 $flags = Revision::compressRevisionText( $data );
 777
 778                 # Write to external storage if required
 779                 if( $wgDefaultExternalStore ) {
 780                         // Store and get the URL
 781                         $data = ExternalStore::insertToDefault( $data );
 782                         if( !$data ) {
 783                                 throw new MWException( "Unable to store text to external storage" );
 784                         }
 785                         if( $flags ) {
 786                                 $flags .= ',';
 787                         }
 788                         $flags .= 'external';
 789                 }
 790
 791                 # Record the text (or external storage URL) to the text table
 792                 if( !isset( $this->mTextId ) ) {
 793                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 794                         $dbw->insert( 'text',
 795                                 array(
 796                                         'old_id'    => $old_id,
 797                                         'old_text'  => $data,
 798                                         'old_flags' => $flags,
 799                                 ), __METHOD__
 800                         );
 801                         $this->mTextId = $dbw->insertId();
 802                 }
 803
 804                 # Record the edit in revisions
 805                 $rev_id = isset( $this->mId )
 806                         ? $this->mId
 807                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 808                 $dbw->insert( 'revision',
 809                         array(
 810                                 'rev_id'         => $rev_id,
 811                                 'rev_page'       => $this->mPage,
 812                                 'rev_text_id'    => $this->mTextId,
 813                                 'rev_comment'    => $this->mComment,
 814                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 815                                 'rev_user'       => $this->mUser,
 816                                 'rev_user_text'  => $this->mUserText,
 817                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 818                                 'rev_deleted'    => $this->mDeleted,
 819                                 'rev_len'            => $this->mSize,
 820                                 'rev_parent_id'  => $this->mParentId ? $this->mParentId : $this->getPreviousRevisionId( $dbw )
 821                         ), __METHOD__
 822                 );
 823
 824                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 825
 826                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 827
 828                 wfProfileOut( __METHOD__ );
 829                 return $this->mId;
 830         }
 831
 832         /**
 833          * Lazy-load the revision's text.
 834          * Currently hardcoded to the 'text' table storage engine.
 835          *
 836          * @return string
 837          */
 838         private function loadText() {
 839                 wfProfileIn( __METHOD__ );
 840
 841                 // Caching may be beneficial for massive use of external storage
 842                 global $wgRevisionCacheExpiry, $wgMemc;
 843                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 844                 if( $wgRevisionCacheExpiry ) {
 845                         $text = $wgMemc->get( $key );
 846                         if( is_string( $text ) ) {
 847                                 wfProfileOut( __METHOD__ );
 848                                 return $text;
 849                         }
 850                 }
 851
 852                 // If we kept data for lazy extraction, use it now...
 853                 if ( isset( $this->mTextRow ) ) {
 854                         $row = $this->mTextRow;
 855                         $this->mTextRow = null;
 856                 } else {
 857                         $row = null;
 858                 }
 859
 860                 if( !$row ) {
 861                         // Text data is immutable; check slaves first.
 862                         $dbr = wfGetDB( DB_SLAVE );
 863                         $row = $dbr->selectRow( 'text',
 864                                 array( 'old_text', 'old_flags' ),
 865                                 array( 'old_id' => $this->getTextId() ),
 866                                 __METHOD__ );
 867                 }
 868
 869                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 870                         // Possible slave lag!
 871                         $dbw = wfGetDB( DB_MASTER );
 872                         $row = $dbw->selectRow( 'text',
 873                                 array( 'old_text', 'old_flags' ),
 874                                 array( 'old_id' => $this->getTextId() ),
 875                                 __METHOD__ );
 876                 }
 877
 878                 $text = self::getRevisionText( $row );
 879
 880                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 881                 if( $wgRevisionCacheExpiry && $text !== false ) {
 882                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 883                 }
 884
 885                 wfProfileOut( __METHOD__ );
 886
 887                 return $text;
 888         }
 889
 890         /**
 891          * Create a new null-revision for insertion into a page's
 892          * history. This will not re-save the text, but simply refer
 893          * to the text from the previous version.
 894          *
 895          * Such revisions can for instance identify page rename
 896          * operations and other such meta-modifications.
 897          *
 898          * @param Database $dbw
 899          * @param int      $pageId ID number of the page to read from
 900          * @param string   $summary
 901          * @param bool     $minor
 902          * @return Revision
 903          */
 904         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 905                 wfProfileIn( __METHOD__ );
 906
 907                 $current = $dbw->selectRow(
 908                         array( 'page', 'revision' ),
 909                         array( 'page_latest', 'rev_text_id' ),
 910                         array(
 911                                 'page_id' => $pageId,
 912                                 'page_latest=rev_id',
 913                                 ),
 914                         __METHOD__ );
 915
 916                 if( $current ) {
 917                         $revision = new Revision( array(
 918                                 'page'       => $pageId,
 919                                 'comment'    => $summary,
 920                                 'minor_edit' => $minor,
 921                                 'text_id'    => $current->rev_text_id,
 922                                 'parent_id'  => $current->page_latest
 923                                 ) );
 924                 } else {
 925                         $revision = null;
 926                 }
 927
 928                 wfProfileOut( __METHOD__ );
 929                 return $revision;
 930         }
 931
 932         /**
 933          * Determine if the current user is allowed to view a particular
 934          * field of this revision, if it's marked as deleted.
 935          * @param int $field one of self::DELETED_TEXT,
 936          *                          self::DELETED_COMMENT,
 937          *                          self::DELETED_USER
 938          * @return bool
 939          */
 940         public function userCan( $field ) {
 941                 if( ( $this->mDeleted & $field ) == $field ) {
 942                         global $wgUser;
 943                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 944                                 ? 'suppressrevision'
 945                                 : 'deleterevision';
 946                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 947                         return $wgUser->isAllowed( $permission );
 948                 } else {
 949                         return true;
 950                 }
 951         }
 952
 953
 954         /**
 955          * Get rev_timestamp from rev_id, without loading the rest of the row
 956          * @param Title $title
 957          * @param integer $id
 958          */
 959         static function getTimestampFromId( $title, $id ) {
 960                 $dbr = wfGetDB( DB_SLAVE );
 961                 $conds = array( 'rev_id' => $id );
 962                 $conds['rev_page'] = $title->getArticleId();
 963                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 964                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
 965                         # Not in slave, try master
 966                         $dbw = wfGetDB( DB_MASTER );
 967                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
 968                 }
 969                 return wfTimestamp( TS_MW, $timestamp );
 970         }
 971
 972         /**
 973          * Get count of revisions per page...not very efficient
 974          * @param Database $db
 975          * @param int $id, page id
 976          */
 977         static function countByPageId( $db, $id ) {
 978                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 979                         array( 'rev_page' => $id ), __METHOD__ );
 980                 if( $row ) {
 981                         return $row->revCount;
 982                 }
 983                 return 0;
 984         }
 985
 986         /**
 987          * Get count of revisions per page...not very efficient
 988          * @param Database $db
 989          * @param Title $title
 990          */
 991         static function countByTitle( $db, $title ) {
 992                 $id = $title->getArticleId();
 993                 if( $id ) {
 994                         return Revision::countByPageId( $db, $id );
 995                 }
 996                 return 0;
 997         }
 998 }
 999
1000 /**
1001  * Aliases for backwards compatibility with 1.6
1002  */
1003 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1004 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1005 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1006 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );