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          * @return Revision
  71          */
  72         public static function newFromArchiveRow( $row, $overrides = array() ) {
  73                 $attribs = $overrides + array(
  74                         'page'       => isset( $row->page_id ) ? $row->page_id : null,
  75                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
  76                         'comment'    => $row->ar_comment,
  77                         'user'       => $row->ar_user,
  78                         'user_text'  => $row->ar_user_text,
  79                         'timestamp'  => $row->ar_timestamp,
  80                         'minor_edit' => $row->ar_minor_edit,
  81                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
  82                         'deleted'    => $row->ar_deleted,
  83                         'len'        => $row->ar_len);
  84                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
  85                         // Pre-1.5 ar_text row
  86                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
  87                         if ( $attribs['text'] === false ) {
  88                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
  89                         }
  90                 }
  91                 return new self( $attribs );
  92         }
  93
  94         /**
  95          * Load a page revision from a given revision ID number.
  96          * Returns null if no such revision can be found.
  97          *
  98          * @param $db DatabaseBase
  99          * @param $id Integer
 100          * @return Revision or null
 101          */
 102         public static function loadFromId( $db, $id ) {
 103                 return Revision::loadFromConds( $db,
 104                         array( 'page_id=rev_page',
 105                                    'rev_id' => intval( $id ) ) );
 106         }
 107
 108         /**
 109          * Load either the current, or a specified, revision
 110          * that's attached to a given page. If not attached
 111          * to that page, will return null.
 112          *
 113          * @param $db DatabaseBase
 114          * @param $pageid Integer
 115          * @param $id Integer
 116          * @return Revision or null
 117          */
 118         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 119                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 120                 if( $id ) {
 121                         $conds['rev_id'] = intval( $id );
 122                 } else {
 123                         $conds[] = 'rev_id=page_latest';
 124                 }
 125                 return Revision::loadFromConds( $db, $conds );
 126         }
 127
 128         /**
 129          * Load either the current, or a specified, revision
 130          * that's attached to a given page. If not attached
 131          * to that page, will return null.
 132          *
 133          * @param $db DatabaseBase
 134          * @param $title Title
 135          * @param $id Integer
 136          * @return Revision or null
 137          */
 138         public static function loadFromTitle( $db, $title, $id = 0 ) {
 139                 if( $id ) {
 140                         $matchId = intval( $id );
 141                 } else {
 142                         $matchId = 'page_latest';
 143                 }
 144                 return Revision::loadFromConds(
 145                         $db,
 146                         array( "rev_id=$matchId",
 147                                    'page_id=rev_page',
 148                                    'page_namespace' => $title->getNamespace(),
 149                                    'page_title'     => $title->getDBkey() ) );
 150         }
 151
 152         /**
 153          * Load the revision for the given title with the given timestamp.
 154          * WARNING: Timestamps may in some circumstances not be unique,
 155          * so this isn't the best key to use.
 156          *
 157          * @param $db DatabaseBase
 158          * @param $title Title
 159          * @param $timestamp String
 160          * @return Revision or null
 161          */
 162         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 163                 return Revision::loadFromConds(
 164                         $db,
 165                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 166                                    'page_id=rev_page',
 167                                    'page_namespace' => $title->getNamespace(),
 168                                    'page_title'     => $title->getDBkey() ) );
 169         }
 170
 171         /**
 172          * Given a set of conditions, fetch a revision.
 173          *
 174          * @param $conditions Array
 175          * @return Revision or null
 176          */
 177         public static function newFromConds( $conditions ) {
 178                 $db = wfGetDB( DB_SLAVE );
 179                 $row = Revision::loadFromConds( $db, $conditions );
 180                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 181                         $dbw = wfGetDB( DB_MASTER );
 182                         $row = Revision::loadFromConds( $dbw, $conditions );
 183                 }
 184                 return $row;
 185         }
 186
 187         /**
 188          * Given a set of conditions, fetch a revision from
 189          * the given database connection.
 190          *
 191          * @param $db DatabaseBase
 192          * @param $conditions Array
 193          * @return Revision or null
 194          */
 195         private static function loadFromConds( $db, $conditions ) {
 196                 $res = Revision::fetchFromConds( $db, $conditions );
 197                 if( $res ) {
 198                         $row = $res->fetchObject();
 199                         $res->free();
 200                         if( $row ) {
 201                                 $ret = new Revision( $row );
 202                                 return $ret;
 203                         }
 204                 }
 205                 $ret = null;
 206                 return $ret;
 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          */
 217         public static function fetchRevision( $title ) {
 218                 return Revision::fetchFromConds(
 219                         wfGetDB( DB_SLAVE ),
 220                         array( 'rev_id=page_latest',
 221                                    'page_namespace' => $title->getNamespace(),
 222                                    'page_title'     => $title->getDBkey(),
 223                                    'page_id=rev_page' ) );
 224         }
 225
 226         /**
 227          * Given a set of conditions, return a ResultWrapper
 228          * which will return matching database rows with the
 229          * fields necessary to build Revision objects.
 230          *
 231          * @param $db DatabaseBase
 232          * @param $conditions Array
 233          * @return ResultWrapper
 234          */
 235         private static function fetchFromConds( $db, $conditions ) {
 236                 $fields = self::selectFields();
 237                 $fields[] = 'page_namespace';
 238                 $fields[] = 'page_title';
 239                 $fields[] = 'page_latest';
 240                 $res = $db->select(
 241                         array( 'page', 'revision' ),
 242                         $fields,
 243                         $conditions,
 244                         __METHOD__,
 245                         array( 'LIMIT' => 1 ) );
 246                 $ret = $db->resultObject( $res );
 247                 return $ret;
 248         }
 249
 250         /**
 251          * Return the list of revision fields that should be selected to create
 252          * a new revision.
 253          */
 254         public static function selectFields() {
 255                 return array(
 256                         'rev_id',
 257                         'rev_page',
 258                         'rev_text_id',
 259                         'rev_timestamp',
 260                         'rev_comment',
 261                         'rev_user_text,'.
 262                         'rev_user',
 263                         'rev_minor_edit',
 264                         'rev_deleted',
 265                         'rev_len',
 266                         'rev_parent_id'
 267                 );
 268         }
 269
 270         /**
 271          * Return the list of text fields that should be selected to read the
 272          * revision text
 273          */
 274         static function selectTextFields() {
 275                 return array(
 276                         'old_text',
 277                         'old_flags'
 278                 );
 279         }
 280
 281         /**
 282          * Return the list of page fields that should be selected from page table
 283          */
 284         static function selectPageFields() {
 285                 return array(
 286                         'page_namespace',
 287                         'page_title',
 288                         'page_latest'
 289                 );
 290         }
 291
 292         /**
 293          * Constructor
 294          *
 295          * @param $row Mixed: either a database row or an array
 296          * @access private
 297          */
 298         function __construct( $row ) {
 299                 if( is_object( $row ) ) {
 300                         $this->mId        = intval( $row->rev_id );
 301                         $this->mPage      = intval( $row->rev_page );
 302                         $this->mTextId    = intval( $row->rev_text_id );
 303                         $this->mComment   =         $row->rev_comment;
 304                         $this->mUserText  =         $row->rev_user_text;
 305                         $this->mUser      = intval( $row->rev_user );
 306                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 307                         $this->mTimestamp =         $row->rev_timestamp;
 308                         $this->mDeleted   = intval( $row->rev_deleted );
 309
 310                         if( !isset( $row->rev_parent_id ) )
 311                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 312                         else
 313                                 $this->mParentId  = intval( $row->rev_parent_id );
 314
 315                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 316                                 $this->mSize = null;
 317                         else
 318                                 $this->mSize = intval( $row->rev_len );
 319
 320                         if( isset( $row->page_latest ) ) {
 321                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 322                                 $this->mTitle = Title::newFromRow( $row );
 323                         } else {
 324                                 $this->mCurrent = false;
 325                                 $this->mTitle = null;
 326                         }
 327
 328                         // Lazy extraction...
 329                         $this->mText      = null;
 330                         if( isset( $row->old_text ) ) {
 331                                 $this->mTextRow = $row;
 332                         } else {
 333                                 // 'text' table row entry will be lazy-loaded
 334                                 $this->mTextRow = null;
 335                         }
 336                 } elseif( is_array( $row ) ) {
 337                         // Build a new revision to be saved...
 338                         global $wgUser;
 339
 340                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 341                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 342                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 343                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 344                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 345                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 346                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 347                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 348                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 349                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 350
 351                         // Enforce spacing trimming on supplied text
 352                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 353                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 354                         $this->mTextRow   = null;
 355
 356                         $this->mTitle     = null; # Load on demand if needed
 357                         $this->mCurrent   = false;
 358                         # If we still have no len_size, see it we have the text to figure it out
 359                         if ( !$this->mSize )
 360                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 361                 } else {
 362                         throw new MWException( 'Revision constructor passed invalid row format.' );
 363                 }
 364                 $this->mUnpatrolled = null;
 365         }
 366
 367         /**
 368          * Get revision ID
 369          *
 370          * @return Integer
 371          */
 372         public function getId() {
 373                 return $this->mId;
 374         }
 375
 376         /**
 377          * Get text row ID
 378          *
 379          * @return Integer
 380          */
 381         public function getTextId() {
 382                 return $this->mTextId;
 383         }
 384
 385         /**
 386          * Get parent revision ID (the original previous page revision)
 387          *
 388          * @return Integer
 389          */
 390         public function getParentId() {
 391                 return $this->mParentId;
 392         }
 393
 394         /**
 395          * Returns the length of the text in this revision, or null if unknown.
 396          *
 397          * @return Integer
 398          */
 399         public function getSize() {
 400                 return $this->mSize;
 401         }
 402
 403         /**
 404          * Returns the title of the page associated with this entry.
 405          *
 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          *
 429          * @param $title Title
 430          */
 431         public function setTitle( $title ) {
 432                 $this->mTitle = $title;
 433         }
 434
 435         /**
 436          * Get the page ID
 437          *
 438          * @return Integer
 439          */
 440         public function getPage() {
 441                 return $this->mPage;
 442         }
 443
 444         /**
 445          * Fetch revision's user id if it's available to the specified audience.
 446          * If the specified audience does not have access to it, zero will be
 447          * returned.
 448          *
 449          * @param $audience Integer: one of:
 450          *      Revision::FOR_PUBLIC       to be displayed to all users
 451          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 452          *      Revision::RAW              get the ID regardless of permissions
 453          *
 454          *
 455          * @return Integer
 456          */
 457         public function getUser( $audience = self::FOR_PUBLIC ) {
 458                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 459                         return 0;
 460                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 461                         return 0;
 462                 } else {
 463                         return $this->mUser;
 464                 }
 465         }
 466
 467         /**
 468          * Fetch revision's user id without regard for the current user's permissions
 469          *
 470          * @return String
 471          */
 472         public function getRawUser() {
 473                 return $this->mUser;
 474         }
 475
 476         /**
 477          * Fetch revision's username if it's available to the specified audience.
 478          * If the specified audience does not have access to the username, an
 479          * empty string will be returned.
 480          *
 481          * @param $audience Integer: one of:
 482          *      Revision::FOR_PUBLIC       to be displayed to all users
 483          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 484          *      Revision::RAW              get the text regardless of permissions
 485          *
 486          * @return string
 487          */
 488         public function getUserText( $audience = self::FOR_PUBLIC ) {
 489                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 490                         return '';
 491                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 492                         return '';
 493                 } else {
 494                         return $this->mUserText;
 495                 }
 496         }
 497
 498         /**
 499          * Fetch revision's username without regard for view restrictions
 500          *
 501          * @return String
 502          */
 503         public function getRawUserText() {
 504                 return $this->mUserText;
 505         }
 506
 507         /**
 508          * Fetch revision comment if it's available to the specified audience.
 509          * If the specified audience does not have access to the comment, an
 510          * empty string will be returned.
 511          *
 512          * @param $audience Integer: one of:
 513          *      Revision::FOR_PUBLIC       to be displayed to all users
 514          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 515          *      Revision::RAW              get the text regardless of permissions
 516          *
 517          * @return String
 518          */
 519         function getComment( $audience = self::FOR_PUBLIC ) {
 520                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 521                         return '';
 522                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 523                         return '';
 524                 } else {
 525                         return $this->mComment;
 526                 }
 527         }
 528
 529         /**
 530          * Fetch revision comment without regard for the current user's permissions
 531          *
 532          * @return String
 533          */
 534         public function getRawComment() {
 535                 return $this->mComment;
 536         }
 537
 538         /**
 539          * @return Boolean
 540          */
 541         public function isMinor() {
 542                 return (bool)$this->mMinorEdit;
 543         }
 544
 545         /**
 546          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 547          */
 548         public function isUnpatrolled() {
 549                 if( $this->mUnpatrolled !== null ) {
 550                         return $this->mUnpatrolled;
 551                 }
 552                 $dbr = wfGetDB( DB_SLAVE );
 553                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 554                         'rc_id',
 555                         array( // Add redundant user,timestamp condition so we can use the existing index
 556                                 'rc_user_text'  => $this->getRawUserText(),
 557                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 558                                 'rc_this_oldid' => $this->getId(),
 559                                 'rc_patrolled'  => 0
 560                         ),
 561                         __METHOD__
 562                 );
 563                 return (int)$this->mUnpatrolled;
 564         }
 565
 566         /**
 567          * int $field one of DELETED_* bitfield constants
 568          *
 569          * @return Boolean
 570          */
 571         public function isDeleted( $field ) {
 572                 return ( $this->mDeleted & $field ) == $field;
 573         }
 574
 575         /**
 576          * Get the deletion bitfield of the revision
 577          */
 578         public function getVisibility() {
 579                 return (int)$this->mDeleted;
 580         }
 581
 582         /**
 583          * Fetch revision text if it's available to the specified audience.
 584          * If the specified audience does not have the ability to view this
 585          * revision, an empty string will be returned.
 586          *
 587          * @param $audience Integer: one of:
 588          *      Revision::FOR_PUBLIC       to be displayed to all users
 589          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 590          *      Revision::RAW              get the text regardless of permissions
 591          *
 592          * @return String
 593          */
 594         public function getText( $audience = self::FOR_PUBLIC ) {
 595                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 596                         return '';
 597                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 598                         return '';
 599                 } else {
 600                         return $this->getRawText();
 601                 }
 602         }
 603
 604         /**
 605          * Alias for getText(Revision::FOR_THIS_USER)
 606          *
 607          * @deprecated since 1.17
 608          * @return String
 609          */
 610         public function revText() {
 611                 wfDeprecated( __METHOD__ );
 612                 return $this->getText( self::FOR_THIS_USER );
 613         }
 614
 615         /**
 616          * Fetch revision text without regard for view restrictions
 617          *
 618          * @return String
 619          */
 620         public function getRawText() {
 621                 if( is_null( $this->mText ) ) {
 622                         // Revision text is immutable. Load on demand:
 623                         $this->mText = $this->loadText();
 624                 }
 625                 return $this->mText;
 626         }
 627
 628         /**
 629          * @return String
 630          */
 631         public function getTimestamp() {
 632                 return wfTimestamp( TS_MW, $this->mTimestamp );
 633         }
 634
 635         /**
 636          * @return Boolean
 637          */
 638         public function isCurrent() {
 639                 return $this->mCurrent;
 640         }
 641
 642         /**
 643          * Get previous revision for this title
 644          *
 645          * @return Revision or null
 646          */
 647         public function getPrevious() {
 648                 if( $this->getTitle() ) {
 649                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 650                         if( $prev ) {
 651                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 652                         }
 653                 }
 654                 return null;
 655         }
 656
 657         /**
 658          * Get next revision for this title
 659          *
 660          * @return Revision or null
 661          */
 662         public function getNext() {
 663                 if( $this->getTitle() ) {
 664                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 665                         if ( $next ) {
 666                                 return Revision::newFromTitle( $this->getTitle(), $next );
 667                         }
 668                 }
 669                 return null;
 670         }
 671
 672         /**
 673          * Get previous revision Id for this page_id
 674          * This is used to populate rev_parent_id on save
 675          *
 676          * @param $db DatabaseBase
 677          * @return Integer
 678          */
 679         private function getPreviousRevisionId( $db ) {
 680                 if( is_null( $this->mPage ) ) {
 681                         return 0;
 682                 }
 683                 # Use page_latest if ID is not given
 684                 if( !$this->mId ) {
 685                         $prevId = $db->selectField( 'page', 'page_latest',
 686                                 array( 'page_id' => $this->mPage ),
 687                                 __METHOD__ );
 688                 } else {
 689                         $prevId = $db->selectField( 'revision', 'rev_id',
 690                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 691                                 __METHOD__,
 692                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 693                 }
 694                 return intval( $prevId );
 695         }
 696
 697         /**
 698           * Get revision text associated with an old or archive row
 699           * $row is usually an object from wfFetchRow(), both the flags and the text
 700           * field must be included
 701           *
 702           * @param $row Object: the text data
 703           * @param $prefix String: table prefix (default 'old_')
 704           * @return String: text the text requested or false on failure
 705           */
 706         public static function getRevisionText( $row, $prefix = 'old_' ) {
 707                 wfProfileIn( __METHOD__ );
 708
 709                 # Get data
 710                 $textField = $prefix . 'text';
 711                 $flagsField = $prefix . 'flags';
 712
 713                 if( isset( $row->$flagsField ) ) {
 714                         $flags = explode( ',', $row->$flagsField );
 715                 } else {
 716                         $flags = array();
 717                 }
 718
 719                 if( isset( $row->$textField ) ) {
 720                         $text = $row->$textField;
 721                 } else {
 722                         wfProfileOut( __METHOD__ );
 723                         return false;
 724                 }
 725
 726                 # Use external methods for external objects, text in table is URL-only then
 727                 if ( in_array( 'external', $flags ) ) {
 728                         $url = $text;
 729                         @list(/* $proto */, $path ) = explode( '://', $url, 2 );
 730                         if( $path == '' ) {
 731                                 wfProfileOut( __METHOD__ );
 732                                 return false;
 733                         }
 734                         $text = ExternalStore::fetchFromURL( $url );
 735                 }
 736
 737                 // If the text was fetched without an error, convert it
 738                 if ( $text !== false ) {
 739                         if( in_array( 'gzip', $flags ) ) {
 740                                 # Deal with optional compression of archived pages.
 741                                 # This can be done periodically via maintenance/compressOld.php, and
 742                                 # as pages are saved if $wgCompressRevisions is set.
 743                                 $text = gzinflate( $text );
 744                         }
 745
 746                         if( in_array( 'object', $flags ) ) {
 747                                 # Generic compressed storage
 748                                 $obj = unserialize( $text );
 749                                 if ( !is_object( $obj ) ) {
 750                                         // Invalid object
 751                                         wfProfileOut( __METHOD__ );
 752                                         return false;
 753                                 }
 754                                 $text = $obj->getText();
 755                         }
 756
 757                         global $wgLegacyEncoding;
 758                         if( $text !== false && $wgLegacyEncoding
 759                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 760                         {
 761                                 # Old revisions kept around in a legacy encoding?
 762                                 # Upconvert on demand.
 763                                 # ("utf8" checked for compatibility with some broken
 764                                 #  conversion scripts 2008-12-30)
 765                                 global $wgContLang;
 766                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 767                         }
 768                 }
 769                 wfProfileOut( __METHOD__ );
 770                 return $text;
 771         }
 772
 773         /**
 774          * If $wgCompressRevisions is enabled, we will compress data.
 775          * The input string is modified in place.
 776          * Return value is the flags field: contains 'gzip' if the
 777          * data is compressed, and 'utf-8' if we're saving in UTF-8
 778          * mode.
 779          *
 780          * @param $text Mixed: reference to a text
 781          * @return String
 782          */
 783         public static function compressRevisionText( &$text ) {
 784                 global $wgCompressRevisions;
 785                 $flags = array();
 786
 787                 # Revisions not marked this way will be converted
 788                 # on load if $wgLegacyCharset is set in the future.
 789                 $flags[] = 'utf-8';
 790
 791                 if( $wgCompressRevisions ) {
 792                         if( function_exists( 'gzdeflate' ) ) {
 793                                 $text = gzdeflate( $text );
 794                                 $flags[] = 'gzip';
 795                         } else {
 796                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 797                         }
 798                 }
 799                 return implode( ',', $flags );
 800         }
 801
 802         /**
 803          * Insert a new revision into the database, returning the new revision ID
 804          * number on success and dies horribly on failure.
 805          *
 806          * @param $dbw DatabaseBase: (master connection)
 807          * @return Integer
 808          */
 809         public function insertOn( $dbw ) {
 810                 global $wgDefaultExternalStore;
 811
 812                 wfProfileIn( __METHOD__ );
 813
 814                 $data = $this->mText;
 815                 $flags = Revision::compressRevisionText( $data );
 816
 817                 # Write to external storage if required
 818                 if( $wgDefaultExternalStore ) {
 819                         // Store and get the URL
 820                         $data = ExternalStore::insertToDefault( $data );
 821                         if( !$data ) {
 822                                 throw new MWException( "Unable to store text to external storage" );
 823                         }
 824                         if( $flags ) {
 825                                 $flags .= ',';
 826                         }
 827                         $flags .= 'external';
 828                 }
 829
 830                 # Record the text (or external storage URL) to the text table
 831                 if( !isset( $this->mTextId ) ) {
 832                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 833                         $dbw->insert( 'text',
 834                                 array(
 835                                         'old_id'    => $old_id,
 836                                         'old_text'  => $data,
 837                                         'old_flags' => $flags,
 838                                 ), __METHOD__
 839                         );
 840                         $this->mTextId = $dbw->insertId();
 841                 }
 842
 843                 if ( $this->mComment === null ) $this->mComment = "";
 844
 845                 # Record the edit in revisions
 846                 $rev_id = isset( $this->mId )
 847                         ? $this->mId
 848                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 849                 $dbw->insert( 'revision',
 850                         array(
 851                                 'rev_id'         => $rev_id,
 852                                 'rev_page'       => $this->mPage,
 853                                 'rev_text_id'    => $this->mTextId,
 854                                 'rev_comment'    => $this->mComment,
 855                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 856                                 'rev_user'       => $this->mUser,
 857                                 'rev_user_text'  => $this->mUserText,
 858                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 859                                 'rev_deleted'    => $this->mDeleted,
 860                                 'rev_len'        => $this->mSize,
 861                                 'rev_parent_id'  => is_null($this->mParentId) ?
 862                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 863                         ), __METHOD__
 864                 );
 865
 866                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 867
 868                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 869
 870                 wfProfileOut( __METHOD__ );
 871                 return $this->mId;
 872         }
 873
 874         /**
 875          * Lazy-load the revision's text.
 876          * Currently hardcoded to the 'text' table storage engine.
 877          *
 878          * @return String
 879          */
 880         protected function loadText() {
 881                 wfProfileIn( __METHOD__ );
 882
 883                 // Caching may be beneficial for massive use of external storage
 884                 global $wgRevisionCacheExpiry, $wgMemc;
 885                 $textId = $this->getTextId();
 886                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 887                 if( $wgRevisionCacheExpiry ) {
 888                         $text = $wgMemc->get( $key );
 889                         if( is_string( $text ) ) {
 890                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 891                                 wfProfileOut( __METHOD__ );
 892                                 return $text;
 893                         }
 894                 }
 895
 896                 // If we kept data for lazy extraction, use it now...
 897                 if ( isset( $this->mTextRow ) ) {
 898                         $row = $this->mTextRow;
 899                         $this->mTextRow = null;
 900                 } else {
 901                         $row = null;
 902                 }
 903
 904                 if( !$row ) {
 905                         // Text data is immutable; check slaves first.
 906                         $dbr = wfGetDB( DB_SLAVE );
 907                         $row = $dbr->selectRow( 'text',
 908                                 array( 'old_text', 'old_flags' ),
 909                                 array( 'old_id' => $this->getTextId() ),
 910                                 __METHOD__ );
 911                 }
 912
 913                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 914                         // Possible slave lag!
 915                         $dbw = wfGetDB( DB_MASTER );
 916                         $row = $dbw->selectRow( 'text',
 917                                 array( 'old_text', 'old_flags' ),
 918                                 array( 'old_id' => $this->getTextId() ),
 919                                 __METHOD__ );
 920                 }
 921
 922                 $text = self::getRevisionText( $row );
 923
 924                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 925                 if( $wgRevisionCacheExpiry && $text !== false ) {
 926                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 927                 }
 928
 929                 wfProfileOut( __METHOD__ );
 930
 931                 return $text;
 932         }
 933
 934         /**
 935          * Create a new null-revision for insertion into a page's
 936          * history. This will not re-save the text, but simply refer
 937          * to the text from the previous version.
 938          *
 939          * Such revisions can for instance identify page rename
 940          * operations and other such meta-modifications.
 941          *
 942          * @param $dbw DatabaseBase
 943          * @param $pageId Integer: ID number of the page to read from
 944          * @param $summary String: revision's summary
 945          * @param $minor Boolean: whether the revision should be considered as minor
 946          * @return Revision|null on error
 947          */
 948         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 949                 wfProfileIn( __METHOD__ );
 950
 951                 $current = $dbw->selectRow(
 952                         array( 'page', 'revision' ),
 953                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 954                         array(
 955                                 'page_id' => $pageId,
 956                                 'page_latest=rev_id',
 957                                 ),
 958                         __METHOD__ );
 959
 960                 if( $current ) {
 961                         $revision = new Revision( array(
 962                                 'page'       => $pageId,
 963                                 'comment'    => $summary,
 964                                 'minor_edit' => $minor,
 965                                 'text_id'    => $current->rev_text_id,
 966                                 'parent_id'  => $current->page_latest,
 967                                 'len'        => $current->rev_len
 968                                 ) );
 969                 } else {
 970                         $revision = null;
 971                 }
 972
 973                 wfProfileOut( __METHOD__ );
 974                 return $revision;
 975         }
 976
 977         /**
 978          * Determine if the current user is allowed to view a particular
 979          * field of this revision, if it's marked as deleted.
 980          *
 981          * @param $field Integer:one of self::DELETED_TEXT,
 982          *                              self::DELETED_COMMENT,
 983          *                              self::DELETED_USER
 984          * @return Boolean
 985          */
 986         public function userCan( $field ) {
 987                 return self::userCanBitfield( $this->mDeleted, $field );
 988         }
 989
 990         /**
 991          * Determine if the current user is allowed to view a particular
 992          * field of this revision, if it's marked as deleted. This is used
 993          * by various classes to avoid duplication.
 994          *
 995          * @param $bitfield Integer: current field
 996          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
 997          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
 998          *                               self::DELETED_USER = File::DELETED_USER
 999          * @return Boolean
1000          */
1001         public static function userCanBitfield( $bitfield, $field ) {
1002                 if( $bitfield & $field ) { // aspect is deleted
1003                         global $wgUser;
1004                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1005                                 $permission = 'suppressrevision';
1006                         } elseif ( $field & self::DELETED_TEXT ) {
1007                                 $permission = 'deletedtext';
1008                         } else {
1009                                 $permission = 'deletedhistory';
1010                         }
1011                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1012                         return $wgUser->isAllowed( $permission );
1013                 } else {
1014                         return true;
1015                 }
1016         }
1017
1018         /**
1019          * Get rev_timestamp from rev_id, without loading the rest of the row
1020          *
1021          * @param $title Title
1022          * @param $id Integer
1023          * @return String
1024          */
1025         static function getTimestampFromId( $title, $id ) {
1026                 $dbr = wfGetDB( DB_SLAVE );
1027                 // Casting fix for DB2
1028                 if ( $id == '' ) {
1029                         $id = 0;
1030                 }
1031                 $conds = array( 'rev_id' => $id );
1032                 $conds['rev_page'] = $title->getArticleId();
1033                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1034                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1035                         # Not in slave, try master
1036                         $dbw = wfGetDB( DB_MASTER );
1037                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1038                 }
1039                 return wfTimestamp( TS_MW, $timestamp );
1040         }
1041
1042         /**
1043          * Get count of revisions per page...not very efficient
1044          *
1045          * @param $db DatabaseBase
1046          * @param $id Integer: page id
1047          * @return Integer
1048          */
1049         static function countByPageId( $db, $id ) {
1050                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1051                         array( 'rev_page' => $id ), __METHOD__ );
1052                 if( $row ) {
1053                         return $row->revCount;
1054                 }
1055                 return 0;
1056         }
1057
1058         /**
1059          * Get count of revisions per page...not very efficient
1060          *
1061          * @param $db DatabaseBase
1062          * @param $title Title
1063          * @return Integer
1064          */
1065         static function countByTitle( $db, $title ) {
1066                 $id = $title->getArticleId();
1067                 if( $id ) {
1068                         return Revision::countByPageId( $db, $id );
1069                 }
1070                 return 0;
1071         }
1072 }
1073
1074 /**
1075  * Aliases for backwards compatibility with 1.6
1076  */
1077 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1078 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1079 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1080 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );