includes/Revision.php

   1 <?php
   2
   3 /**
   4  * @todo document
   5  */
   6 class Revision {
   7         const DELETED_TEXT = 1;
   8         const DELETED_COMMENT = 2;
   9         const DELETED_USER = 4;
  10         const DELETED_RESTRICTED = 8;
  11         // Convenience field
  12         const SUPPRESSED_USER = 12;
  13         // Audience options for Revision::getText()
  14         const FOR_PUBLIC = 1;
  15         const FOR_THIS_USER = 2;
  16         const RAW = 3;
  17
  18         /**
  19          * Load a page revision from a given revision ID number.
  20          * Returns null if no such revision can be found.
  21          *
  22          * @param $id Integer
  23          * @return Revision or null
  24          */
  25         public static function newFromId( $id ) {
  26                 return Revision::newFromConds(
  27                         array( 'page_id=rev_page',
  28                                'rev_id' => intval( $id ) ) );
  29         }
  30
  31         /**
  32          * Load either the current, or a specified, revision
  33          * that's attached to a given title. If not attached
  34          * to that title, will return null.
  35          *
  36          * @param $title Title
  37          * @param $id Integer
  38          * @return Revision or null
  39          */
  40         public static function newFromTitle( $title, $id = 0 ) {
  41                 $conds = array(
  42                         'page_namespace' => $title->getNamespace(),
  43                         'page_title' => $title->getDBkey()
  44                 );
  45                 if ( $id ) {
  46                         // Use the specified ID
  47                         $conds['rev_id'] = $id;
  48                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  49                         // Get the latest revision ID from the master
  50                         $dbw = wfGetDB( DB_MASTER );
  51                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  52                         if ( $latest === false ) {
  53                                 // Page does not exist
  54                                 return null;
  55                         }
  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          * Make a fake revision object from an archive table row. This is queried
  67          * for permissions or even inserted (as in Special:Undelete)
  68          * @todo Fixme: should be a subclass for RevisionDelete. [TS]
  69          */
  70         public static function newFromArchiveRow( $row, $overrides = array() ) {
  71                 $attribs = $overrides + array(
  72                         'page'       => isset( $row->page_id ) ? $row->page_id : null,
  73                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
  74                         'comment'    => $row->ar_comment,
  75                         'user'       => $row->ar_user,
  76                         'user_text'  => $row->ar_user_text,
  77                         'timestamp'  => $row->ar_timestamp,
  78                         'minor_edit' => $row->ar_minor_edit,
  79                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
  80                         'deleted'    => $row->ar_deleted,
  81                         'len'        => $row->ar_len);
  82                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
  83                         // Pre-1.5 ar_text row
  84                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
  85                 }
  86                 return new self( $attribs );
  87         }
  88
  89         /**
  90          * Load a page revision from a given revision ID number.
  91          * Returns null if no such revision can be found.
  92          *
  93          * @param $db DatabaseBase
  94          * @param $id Integer
  95          * @return Revision or null
  96          */
  97         public static function loadFromId( $db, $id ) {
  98                 return Revision::loadFromConds( $db,
  99                         array( 'page_id=rev_page',
 100                                'rev_id' => intval( $id ) ) );
 101         }
 102
 103         /**
 104          * Load either the current, or a specified, revision
 105          * that's attached to a given page. If not attached
 106          * to that page, will return null.
 107          *
 108          * @param $db DatabaseBase
 109          * @param $pageid Integer
 110          * @param $id Integer
 111          * @return Revision or null
 112          */
 113         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 114                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 115                 if( $id ) {
 116                         $conds['rev_id'] = intval( $id );
 117                 } else {
 118                         $conds[] = 'rev_id=page_latest';
 119                 }
 120                 return Revision::loadFromConds( $db, $conds );
 121         }
 122
 123         /**
 124          * Load either the current, or a specified, revision
 125          * that's attached to a given page. If not attached
 126          * to that page, will return null.
 127          *
 128          * @param $db DatabaseBase
 129          * @param $title Title
 130          * @param $id Integer
 131          * @return Revision or null
 132          */
 133         public static function loadFromTitle( $db, $title, $id = 0 ) {
 134                 if( $id ) {
 135                         $matchId = intval( $id );
 136                 } else {
 137                         $matchId = 'page_latest';
 138                 }
 139                 return Revision::loadFromConds(
 140                         $db,
 141                         array( "rev_id=$matchId",
 142                                'page_id=rev_page',
 143                                'page_namespace' => $title->getNamespace(),
 144                                'page_title'     => $title->getDBkey() ) );
 145         }
 146
 147         /**
 148          * Load the revision for the given title with the given timestamp.
 149          * WARNING: Timestamps may in some circumstances not be unique,
 150          * so this isn't the best key to use.
 151          *
 152          * @param $db Database
 153          * @param $title Title
 154          * @param $timestamp String
 155          * @return Revision or null
 156          */
 157         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 158                 return Revision::loadFromConds(
 159                         $db,
 160                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 161                                'page_id=rev_page',
 162                                'page_namespace' => $title->getNamespace(),
 163                                'page_title'     => $title->getDBkey() ) );
 164         }
 165
 166         /**
 167          * Given a set of conditions, fetch a revision.
 168          *
 169          * @param $conditions Array
 170          * @return Revision or null
 171          */
 172         public static function newFromConds( $conditions ) {
 173                 $db = wfGetDB( DB_SLAVE );
 174                 $row = Revision::loadFromConds( $db, $conditions );
 175                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 176                         $dbw = wfGetDB( DB_MASTER );
 177                         $row = Revision::loadFromConds( $dbw, $conditions );
 178                 }
 179                 return $row;
 180         }
 181
 182         /**
 183          * Given a set of conditions, fetch a revision from
 184          * the given database connection.
 185          *
 186          * @param $db Database
 187          * @param $conditions Array
 188          * @return Revision or null
 189          */
 190         private static function loadFromConds( $db, $conditions ) {
 191                 $res = Revision::fetchFromConds( $db, $conditions );
 192                 if( $res ) {
 193                         $row = $res->fetchObject();
 194                         $res->free();
 195                         if( $row ) {
 196                                 $ret = new Revision( $row );
 197                                 return $ret;
 198                         }
 199                 }
 200                 $ret = null;
 201                 return $ret;
 202         }
 203
 204         /**
 205          * Return a wrapper for a series of database rows to
 206          * fetch all of a given page's revisions in turn.
 207          * Each row can be fed to the constructor to get objects.
 208          *
 209          * @param $title Title
 210          * @return ResultWrapper
 211          */
 212         public static function fetchRevision( $title ) {
 213                 return Revision::fetchFromConds(
 214                         wfGetDB( DB_SLAVE ),
 215                         array( 'rev_id=page_latest',
 216                                'page_namespace' => $title->getNamespace(),
 217                                'page_title'     => $title->getDBkey(),
 218                                'page_id=rev_page' ) );
 219         }
 220
 221         /**
 222          * Given a set of conditions, return a ResultWrapper
 223          * which will return matching database rows with the
 224          * fields necessary to build Revision objects.
 225          *
 226          * @param $db Database
 227          * @param $conditions Array
 228          * @return ResultWrapper
 229          */
 230         private static function fetchFromConds( $db, $conditions ) {
 231                 $fields = self::selectFields();
 232                 $fields[] = 'page_namespace';
 233                 $fields[] = 'page_title';
 234                 $fields[] = 'page_latest';
 235                 $res = $db->select(
 236                         array( 'page', 'revision' ),
 237                         $fields,
 238                         $conditions,
 239                         __METHOD__,
 240                         array( 'LIMIT' => 1 ) );
 241                 $ret = $db->resultObject( $res );
 242                 return $ret;
 243         }
 244
 245         /**
 246          * Return the list of revision fields that should be selected to create
 247          * a new revision.
 248          */
 249         static function selectFields() {
 250                 return array(
 251                         'rev_id',
 252                         'rev_page',
 253                         'rev_text_id',
 254                         'rev_timestamp',
 255                         'rev_comment',
 256                         'rev_user_text,'.
 257                         'rev_user',
 258                         'rev_minor_edit',
 259                         'rev_deleted',
 260                         'rev_len',
 261                         'rev_parent_id'
 262                 );
 263         }
 264
 265         /**
 266          * Return the list of text fields that should be selected to read the
 267          * revision text
 268          */
 269         static function selectTextFields() {
 270                 return array(
 271                         'old_text',
 272                         'old_flags'
 273                 );
 274         }
 275
 276         /**
 277          * Return the list of page fields that should be selected from page table
 278          */
 279         static function selectPageFields() {
 280                 return array(
 281                         'page_namespace',
 282                         'page_title',
 283                         'page_latest'
 284                 );
 285         }
 286
 287         /**
 288          * Constructor
 289          *
 290          * @param $row Mixed: either a database row or an array
 291          * @access private
 292          */
 293         function __construct( $row ) {
 294                 if( is_object( $row ) ) {
 295                         $this->mId        = intval( $row->rev_id );
 296                         $this->mPage      = intval( $row->rev_page );
 297                         $this->mTextId    = intval( $row->rev_text_id );
 298                         $this->mComment   =         $row->rev_comment;
 299                         $this->mUserText  =         $row->rev_user_text;
 300                         $this->mUser      = intval( $row->rev_user );
 301                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 302                         $this->mTimestamp =         $row->rev_timestamp;
 303                         $this->mDeleted   = intval( $row->rev_deleted );
 304
 305                         if( !isset( $row->rev_parent_id ) )
 306                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 307                         else
 308                                 $this->mParentId  = intval( $row->rev_parent_id );
 309
 310                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 311                                 $this->mSize = null;
 312                         else
 313                                 $this->mSize = intval( $row->rev_len );
 314
 315                         if( isset( $row->page_latest ) ) {
 316                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 317                                 $this->mTitle = Title::newFromRow( $row );
 318                         } else {
 319                                 $this->mCurrent = false;
 320                                 $this->mTitle = null;
 321                         }
 322
 323                         // Lazy extraction...
 324                         $this->mText      = null;
 325                         if( isset( $row->old_text ) ) {
 326                                 $this->mTextRow = $row;
 327                         } else {
 328                                 // 'text' table row entry will be lazy-loaded
 329                                 $this->mTextRow = null;
 330                         }
 331                 } elseif( is_array( $row ) ) {
 332                         // Build a new revision to be saved...
 333                         global $wgUser;
 334
 335                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 336                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 337                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 338                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 339                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 340                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 341                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 342                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 343                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 344                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 345
 346                         // Enforce spacing trimming on supplied text
 347                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 348                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 349                         $this->mTextRow   = null;
 350
 351                         $this->mTitle     = null; # Load on demand if needed
 352                         $this->mCurrent   = false;
 353                         # If we still have no len_size, see it we have the text to figure it out
 354                         if ( !$this->mSize )
 355                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 356                 } else {
 357                         throw new MWException( 'Revision constructor passed invalid row format.' );
 358                 }
 359                 $this->mUnpatrolled = null;
 360         }
 361
 362         /**
 363          * Get revision ID
 364          *
 365          * @return Integer
 366          */
 367         public function getId() {
 368                 return $this->mId;
 369         }
 370
 371         /**
 372          * Get text row ID
 373          *
 374          * @return Integer
 375          */
 376         public function getTextId() {
 377                 return $this->mTextId;
 378         }
 379
 380         /**
 381          * Get parent revision ID (the original previous page revision)
 382          *
 383          * @return Integer
 384          */
 385         public function getParentId() {
 386                 return $this->mParentId;
 387         }
 388
 389         /**
 390          * Returns the length of the text in this revision, or null if unknown.
 391          *
 392          * @return Integer
 393          */
 394         public function getSize() {
 395                 return $this->mSize;
 396         }
 397
 398         /**
 399          * Returns the title of the page associated with this entry.
 400          *
 401          * @return Title
 402          */
 403         public function getTitle() {
 404                 if( isset( $this->mTitle ) ) {
 405                         return $this->mTitle;
 406                 }
 407                 $dbr = wfGetDB( DB_SLAVE );
 408                 $row = $dbr->selectRow(
 409                         array( 'page', 'revision' ),
 410                         array( 'page_namespace', 'page_title' ),
 411                         array( 'page_id=rev_page',
 412                                'rev_id' => $this->mId ),
 413                         'Revision::getTitle' );
 414                 if( $row ) {
 415                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 416                                                           $row->page_title );
 417                 }
 418                 return $this->mTitle;
 419         }
 420
 421         /**
 422          * Set the title of the revision
 423          *
 424          * @param $title Title
 425          */
 426         public function setTitle( $title ) {
 427                 $this->mTitle = $title;
 428         }
 429
 430         /**
 431          * Get the page ID
 432          *
 433          * @return Integer
 434          */
 435         public function getPage() {
 436                 return $this->mPage;
 437         }
 438
 439         /**
 440          * Fetch revision's user id if it's available to the specified audience.
 441          * If the specified audience does not have access to it, zero will be
 442          * returned.
 443          *
 444          * @param $audience Integer: one of:
 445          *      Revision::FOR_PUBLIC       to be displayed to all users
 446          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 447          *      Revision::RAW              get the ID regardless of permissions
 448          *
 449          *
 450          * @return Integer
 451          */
 452         public function getUser( $audience = self::FOR_PUBLIC ) {
 453                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 454                         return 0;
 455                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 456                         return 0;
 457                 } else {
 458                         return $this->mUser;
 459                 }
 460         }
 461
 462         /**
 463          * Fetch revision's user id without regard for the current user's permissions
 464          *
 465          * @return String
 466          */
 467         public function getRawUser() {
 468                 return $this->mUser;
 469         }
 470
 471         /**
 472          * Fetch revision's username if it's available to the specified audience.
 473          * If the specified audience does not have access to the username, an
 474          * empty string will be returned.
 475          *
 476          * @param $audience Integer: 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 text regardless of permissions
 480          *
 481          * @return string
 482          */
 483         public function getUserText( $audience = self::FOR_PUBLIC ) {
 484                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 485                         return '';
 486                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 487                         return '';
 488                 } else {
 489                         return $this->mUserText;
 490                 }
 491         }
 492
 493         /**
 494          * Fetch revision's username without regard for view restrictions
 495          *
 496          * @return String
 497          */
 498         public function getRawUserText() {
 499                 return $this->mUserText;
 500         }
 501
 502         /**
 503          * Fetch revision comment if it's available to the specified audience.
 504          * If the specified audience does not have access to the comment, an
 505          * empty string will be returned.
 506          *
 507          * @param $audience Integer: 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         function getComment( $audience = self::FOR_PUBLIC ) {
 515                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 516                         return '';
 517                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 518                         return '';
 519                 } else {
 520                         return $this->mComment;
 521                 }
 522         }
 523
 524         /**
 525          * Fetch revision comment without regard for the current user's permissions
 526          *
 527          * @return String
 528          */
 529         public function getRawComment() {
 530                 return $this->mComment;
 531         }
 532
 533         /**
 534          * @return Boolean
 535          */
 536         public function isMinor() {
 537                 return (bool)$this->mMinorEdit;
 538         }
 539
 540         /**
 541          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 542          */
 543         public function isUnpatrolled() {
 544                 if( $this->mUnpatrolled !== null ) {
 545                         return $this->mUnpatrolled;
 546                 }
 547                 $dbr = wfGetDB( DB_SLAVE );
 548                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 549                         'rc_id',
 550                         array( // Add redundant user,timestamp condition so we can use the existing index
 551                                 'rc_user_text'  => $this->getRawUserText(),
 552                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 553                                 'rc_this_oldid' => $this->getId(),
 554                                 'rc_patrolled'  => 0
 555                         ),
 556                         __METHOD__
 557                 );
 558                 return (int)$this->mUnpatrolled;
 559         }
 560
 561         /**
 562          * int $field one of DELETED_* bitfield constants
 563          *
 564          * @return Boolean
 565          */
 566         public function isDeleted( $field ) {
 567                 return ( $this->mDeleted & $field ) == $field;
 568         }
 569
 570         /**
 571          * Get the deletion bitfield of the revision
 572          */
 573         public function getVisibility() {
 574                 return (int)$this->mDeleted;
 575         }
 576
 577         /**
 578          * Fetch revision text if it's available to the specified audience.
 579          * If the specified audience does not have the ability to view this
 580          * revision, an empty string will be returned.
 581          *
 582          * @param $audience Integer: one of:
 583          *      Revision::FOR_PUBLIC       to be displayed to all users
 584          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 585          *      Revision::RAW              get the text regardless of permissions
 586          *
 587          *
 588          * @return String
 589          */
 590         public function getText( $audience = self::FOR_PUBLIC ) {
 591                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 592                         return '';
 593                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 594                         return '';
 595                 } else {
 596                         return $this->getRawText();
 597                 }
 598         }
 599
 600         /**
 601          * Alias for getText(Revision::FOR_THIS_USER)
 602          *
 603          * @deprecated
 604          * @return String
 605          */
 606         public function revText() {
 607                 return $this->getText( self::FOR_THIS_USER );
 608         }
 609
 610         /**
 611          * Fetch revision text without regard for view restrictions
 612          *
 613          * @return String
 614          */
 615         public function getRawText() {
 616                 if( is_null( $this->mText ) ) {
 617                         // Revision text is immutable. Load on demand:
 618                         $this->mText = $this->loadText();
 619                 }
 620                 return $this->mText;
 621         }
 622
 623         /**
 624          * @return String
 625          */
 626         public function getTimestamp() {
 627                 return wfTimestamp( TS_MW, $this->mTimestamp );
 628         }
 629
 630         /**
 631          * @return Boolean
 632          */
 633         public function isCurrent() {
 634                 return $this->mCurrent;
 635         }
 636
 637         /**
 638          * Get previous revision for this title
 639          *
 640          * @return Revision or null
 641          */
 642         public function getPrevious() {
 643                 if( $this->getTitle() ) {
 644                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 645                         if( $prev ) {
 646                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 647                         }
 648                 }
 649                 return null;
 650         }
 651
 652         /**
 653          * Get next revision for this title
 654          *
 655          * @return Revision or null
 656          */
 657         public function getNext() {
 658                 if( $this->getTitle() ) {
 659                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 660                         if ( $next ) {
 661                                 return Revision::newFromTitle( $this->getTitle(), $next );
 662                         }
 663                 }
 664                 return null;
 665         }
 666
 667         /**
 668          * Get previous revision Id for this page_id
 669          * This is used to populate rev_parent_id on save
 670          *
 671          * @param $db DatabaseBase
 672          * @return Integer
 673          */
 674         private function getPreviousRevisionId( $db ) {
 675                 if( is_null( $this->mPage ) ) {
 676                         return 0;
 677                 }
 678                 # Use page_latest if ID is not given
 679                 if( !$this->mId ) {
 680                         $prevId = $db->selectField( 'page', 'page_latest',
 681                                 array( 'page_id' => $this->mPage ),
 682                                 __METHOD__ );
 683                 } else {
 684                         $prevId = $db->selectField( 'revision', 'rev_id',
 685                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 686                                 __METHOD__,
 687                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 688                 }
 689                 return intval( $prevId );
 690         }
 691
 692         /**
 693           * Get revision text associated with an old or archive row
 694           * $row is usually an object from wfFetchRow(), both the flags and the text
 695           * field must be included
 696           *
 697           * @param $row Object: the text data
 698           * @param $prefix String: table prefix (default 'old_')
 699           * @return String: text the text requested or false on failure
 700           */
 701         public static function getRevisionText( $row, $prefix = 'old_' ) {
 702                 wfProfileIn( __METHOD__ );
 703
 704                 # Get data
 705                 $textField = $prefix . 'text';
 706                 $flagsField = $prefix . 'flags';
 707
 708                 if( isset( $row->$flagsField ) ) {
 709                         $flags = explode( ',', $row->$flagsField );
 710                 } else {
 711                         $flags = array();
 712                 }
 713
 714                 if( isset( $row->$textField ) ) {
 715                         $text = $row->$textField;
 716                 } else {
 717                         wfProfileOut( __METHOD__ );
 718                         return false;
 719                 }
 720
 721                 # Use external methods for external objects, text in table is URL-only then
 722                 if ( in_array( 'external', $flags ) ) {
 723                         $url = $text;
 724                         @list(/* $proto */, $path ) = explode( '://', $url, 2 );
 725                         if( $path == '' ) {
 726                                 wfProfileOut( __METHOD__ );
 727                                 return false;
 728                         }
 729                         $text = ExternalStore::fetchFromURL( $url );
 730                 }
 731
 732                 // If the text was fetched without an error, convert it
 733                 if ( $text !== false ) {
 734                         if( in_array( 'gzip', $flags ) ) {
 735                                 # Deal with optional compression of archived pages.
 736                                 # This can be done periodically via maintenance/compressOld.php, and
 737                                 # as pages are saved if $wgCompressRevisions is set.
 738                                 $text = gzinflate( $text );
 739                         }
 740
 741                         if( in_array( 'object', $flags ) ) {
 742                                 # Generic compressed storage
 743                                 $obj = unserialize( $text );
 744                                 if ( !is_object( $obj ) ) {
 745                                         // Invalid object
 746                                         wfProfileOut( __METHOD__ );
 747                                         return false;
 748                                 }
 749                                 $text = $obj->getText();
 750                         }
 751
 752                         global $wgLegacyEncoding;
 753                         if( $text !== false && $wgLegacyEncoding
 754                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 755                         {
 756                                 # Old revisions kept around in a legacy encoding?
 757                                 # Upconvert on demand.
 758                                 # ("utf8" checked for compatibility with some broken
 759                                 #  conversion scripts 2008-12-30)
 760                                 global $wgInputEncoding, $wgContLang;
 761                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 762                         }
 763                 }
 764                 wfProfileOut( __METHOD__ );
 765                 return $text;
 766         }
 767
 768         /**
 769          * If $wgCompressRevisions is enabled, we will compress data.
 770          * The input string is modified in place.
 771          * Return value is the flags field: contains 'gzip' if the
 772          * data is compressed, and 'utf-8' if we're saving in UTF-8
 773          * mode.
 774          *
 775          * @param $text Mixed: reference to a text
 776          * @return String
 777          */
 778         public static function compressRevisionText( &$text ) {
 779                 global $wgCompressRevisions;
 780                 $flags = array();
 781
 782                 # Revisions not marked this way will be converted
 783                 # on load if $wgLegacyCharset is set in the future.
 784                 $flags[] = 'utf-8';
 785
 786                 if( $wgCompressRevisions ) {
 787                         if( function_exists( 'gzdeflate' ) ) {
 788                                 $text = gzdeflate( $text );
 789                                 $flags[] = 'gzip';
 790                         } else {
 791                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 792                         }
 793                 }
 794                 return implode( ',', $flags );
 795         }
 796
 797         /**
 798          * Insert a new revision into the database, returning the new revision ID
 799          * number on success and dies horribly on failure.
 800          *
 801          * @param $dbw DatabaseBase: (master connection)
 802          * @return Integer
 803          */
 804         public function insertOn( $dbw ) {
 805                 global $wgDefaultExternalStore;
 806
 807                 wfProfileIn( __METHOD__ );
 808
 809                 $data = $this->mText;
 810                 $flags = Revision::compressRevisionText( $data );
 811
 812                 # Write to external storage if required
 813                 if( $wgDefaultExternalStore ) {
 814                         // Store and get the URL
 815                         $data = ExternalStore::insertToDefault( $data );
 816                         if( !$data ) {
 817                                 throw new MWException( "Unable to store text to external storage" );
 818                         }
 819                         if( $flags ) {
 820                                 $flags .= ',';
 821                         }
 822                         $flags .= 'external';
 823                 }
 824
 825                 # Record the text (or external storage URL) to the text table
 826                 if( !isset( $this->mTextId ) ) {
 827                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 828                         $dbw->insert( 'text',
 829                                 array(
 830                                         'old_id'    => $old_id,
 831                                         'old_text'  => $data,
 832                                         'old_flags' => $flags,
 833                                 ), __METHOD__
 834                         );
 835                         $this->mTextId = $dbw->insertId();
 836                 }
 837
 838                 if ( $this->mComment === null ) $this->mComment = "";
 839
 840                 # Record the edit in revisions
 841                 $rev_id = isset( $this->mId )
 842                         ? $this->mId
 843                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 844                 $dbw->insert( 'revision',
 845                         array(
 846                                 'rev_id'         => $rev_id,
 847                                 'rev_page'       => $this->mPage,
 848                                 'rev_text_id'    => $this->mTextId,
 849                                 'rev_comment'    => $this->mComment,
 850                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 851                                 'rev_user'       => $this->mUser,
 852                                 'rev_user_text'  => $this->mUserText,
 853                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 854                                 'rev_deleted'    => $this->mDeleted,
 855                                 'rev_len'        => $this->mSize,
 856                                 'rev_parent_id'  => is_null($this->mParentId) ?
 857                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 858                         ), __METHOD__
 859                 );
 860
 861                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 862
 863                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 864
 865                 wfProfileOut( __METHOD__ );
 866                 return $this->mId;
 867         }
 868
 869         /**
 870          * Lazy-load the revision's text.
 871          * Currently hardcoded to the 'text' table storage engine.
 872          *
 873          * @return String
 874          */
 875         protected function loadText() {
 876                 wfProfileIn( __METHOD__ );
 877
 878                 // Caching may be beneficial for massive use of external storage
 879                 global $wgRevisionCacheExpiry, $wgMemc;
 880                 $textId = $this->getTextId();
 881                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 882                 if( $wgRevisionCacheExpiry ) {
 883                         $text = $wgMemc->get( $key );
 884                         if( is_string( $text ) ) {
 885                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 886                                 wfProfileOut( __METHOD__ );
 887                                 return $text;
 888                         }
 889                 }
 890
 891                 // If we kept data for lazy extraction, use it now...
 892                 if ( isset( $this->mTextRow ) ) {
 893                         $row = $this->mTextRow;
 894                         $this->mTextRow = null;
 895                 } else {
 896                         $row = null;
 897                 }
 898
 899                 if( !$row ) {
 900                         // Text data is immutable; check slaves first.
 901                         $dbr = wfGetDB( DB_SLAVE );
 902                         $row = $dbr->selectRow( 'text',
 903                                 array( 'old_text', 'old_flags' ),
 904                                 array( 'old_id' => $this->getTextId() ),
 905                                 __METHOD__ );
 906                 }
 907
 908                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 909                         // Possible slave lag!
 910                         $dbw = wfGetDB( DB_MASTER );
 911                         $row = $dbw->selectRow( 'text',
 912                                 array( 'old_text', 'old_flags' ),
 913                                 array( 'old_id' => $this->getTextId() ),
 914                                 __METHOD__ );
 915                 }
 916
 917                 $text = self::getRevisionText( $row );
 918
 919                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 920                 if( $wgRevisionCacheExpiry && $text !== false ) {
 921                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 922                 }
 923
 924                 wfProfileOut( __METHOD__ );
 925
 926                 return $text;
 927         }
 928
 929         /**
 930          * Create a new null-revision for insertion into a page's
 931          * history. This will not re-save the text, but simply refer
 932          * to the text from the previous version.
 933          *
 934          * Such revisions can for instance identify page rename
 935          * operations and other such meta-modifications.
 936          *
 937          * @param $dbw DatabaseBase
 938          * @param $pageId Integer: ID number of the page to read from
 939          * @param $summary String: revision's summary
 940          * @param $minor Boolean: whether the revision should be considered as minor
 941          * @return Mixed: Revision, or null on error
 942          */
 943         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 944                 wfProfileIn( __METHOD__ );
 945
 946                 $current = $dbw->selectRow(
 947                         array( 'page', 'revision' ),
 948                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 949                         array(
 950                                 'page_id' => $pageId,
 951                                 'page_latest=rev_id',
 952                                 ),
 953                         __METHOD__ );
 954
 955                 if( $current ) {
 956                         $revision = new Revision( array(
 957                                 'page'       => $pageId,
 958                                 'comment'    => $summary,
 959                                 'minor_edit' => $minor,
 960                                 'text_id'    => $current->rev_text_id,
 961                                 'parent_id'  => $current->page_latest,
 962                                 'len'        => $current->rev_len
 963                                 ) );
 964                 } else {
 965                         $revision = null;
 966                 }
 967
 968                 wfProfileOut( __METHOD__ );
 969                 return $revision;
 970         }
 971
 972         /**
 973          * Determine if the current user is allowed to view a particular
 974          * field of this revision, if it's marked as deleted.
 975          *
 976          * @param $field Integer:one of self::DELETED_TEXT,
 977          *                              self::DELETED_COMMENT,
 978          *                              self::DELETED_USER
 979          * @return Boolean
 980          */
 981         public function userCan( $field ) {
 982                 return self::userCanBitfield( $this->mDeleted, $field );
 983         }
 984
 985         /**
 986          * Determine if the current user is allowed to view a particular
 987          * field of this revision, if it's marked as deleted. This is used
 988          * by various classes to avoid duplication.
 989          *
 990          * @param $bitfield Integer: current field
 991          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
 992          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
 993          *                               self::DELETED_USER = File::DELETED_USER
 994          * @return Boolean
 995          */
 996         public static function userCanBitfield( $bitfield, $field ) {
 997                 if( $bitfield & $field ) { // aspect is deleted
 998                         global $wgUser;
 999                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1000                                 $permission = 'suppressrevision';
1001                         } elseif ( $field & self::DELETED_TEXT ) {
1002                                 $permission = 'deletedtext';
1003                         } else {
1004                                 $permission = 'deletedhistory';
1005                         }
1006                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1007                         return $wgUser->isAllowed( $permission );
1008                 } else {
1009                         return true;
1010                 }
1011         }
1012
1013         /**
1014          * Get rev_timestamp from rev_id, without loading the rest of the row
1015          *
1016          * @param $title Title
1017          * @param $id Integer
1018          * @return String
1019          */
1020         static function getTimestampFromId( $title, $id ) {
1021                 $dbr = wfGetDB( DB_SLAVE );
1022                 // Casting fix for DB2
1023                 if ( $id == '' ) {
1024                         $id = 0;
1025                 }
1026                 $conds = array( 'rev_id' => $id );
1027                 $conds['rev_page'] = $title->getArticleId();
1028                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1029                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1030                         # Not in slave, try master
1031                         $dbw = wfGetDB( DB_MASTER );
1032                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1033                 }
1034                 return wfTimestamp( TS_MW, $timestamp );
1035         }
1036
1037         /**
1038          * Get count of revisions per page...not very efficient
1039          *
1040          * @param $db DatabaseBase
1041          * @param $id Integer: page id
1042          * @return Integer
1043          */
1044         static function countByPageId( $db, $id ) {
1045                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1046                         array( 'rev_page' => $id ), __METHOD__ );
1047                 if( $row ) {
1048                         return $row->revCount;
1049                 }
1050                 return 0;
1051         }
1052
1053         /**
1054          * Get count of revisions per page...not very efficient
1055          *
1056          * @param $db DatabaseBase
1057          * @param $title Title
1058          * @return Integer
1059          */
1060         static function countByTitle( $db, $title ) {
1061                 $id = $title->getArticleId();
1062                 if( $id ) {
1063                         return Revision::countByPageId( $db, $id );
1064                 }
1065                 return 0;
1066         }
1067 }
1068
1069 /**
1070  * Aliases for backwards compatibility with 1.6
1071  */
1072 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1073 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1074 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1075 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );