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                         if ( $attribs['text'] === false ) {
  86                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
  87                         }
  88                 }
  89                 return new self( $attribs );
  90         }
  91
  92         /**
  93          * Load a page revision from a given revision ID number.
  94          * Returns null if no such revision can be found.
  95          *
  96          * @param $db DatabaseBase
  97          * @param $id Integer
  98          * @return Revision or null
  99          */
 100         public static function loadFromId( $db, $id ) {
 101                 return Revision::loadFromConds( $db,
 102                         array( 'page_id=rev_page',
 103                                'rev_id' => intval( $id ) ) );
 104         }
 105
 106         /**
 107          * Load either the current, or a specified, revision
 108          * that's attached to a given page. If not attached
 109          * to that page, will return null.
 110          *
 111          * @param $db DatabaseBase
 112          * @param $pageid Integer
 113          * @param $id Integer
 114          * @return Revision or null
 115          */
 116         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 117                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 118                 if( $id ) {
 119                         $conds['rev_id'] = intval( $id );
 120                 } else {
 121                         $conds[] = 'rev_id=page_latest';
 122                 }
 123                 return Revision::loadFromConds( $db, $conds );
 124         }
 125
 126         /**
 127          * Load either the current, or a specified, revision
 128          * that's attached to a given page. If not attached
 129          * to that page, will return null.
 130          *
 131          * @param $db DatabaseBase
 132          * @param $title Title
 133          * @param $id Integer
 134          * @return Revision or null
 135          */
 136         public static function loadFromTitle( $db, $title, $id = 0 ) {
 137                 if( $id ) {
 138                         $matchId = intval( $id );
 139                 } else {
 140                         $matchId = 'page_latest';
 141                 }
 142                 return Revision::loadFromConds(
 143                         $db,
 144                         array( "rev_id=$matchId",
 145                                'page_id=rev_page',
 146                                'page_namespace' => $title->getNamespace(),
 147                                'page_title'     => $title->getDBkey() ) );
 148         }
 149
 150         /**
 151          * Load the revision for the given title with the given timestamp.
 152          * WARNING: Timestamps may in some circumstances not be unique,
 153          * so this isn't the best key to use.
 154          *
 155          * @param $db DatabaseBase
 156          * @param $title Title
 157          * @param $timestamp String
 158          * @return Revision or null
 159          */
 160         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 161                 return Revision::loadFromConds(
 162                         $db,
 163                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 164                                'page_id=rev_page',
 165                                'page_namespace' => $title->getNamespace(),
 166                                'page_title'     => $title->getDBkey() ) );
 167         }
 168
 169         /**
 170          * Given a set of conditions, fetch a revision.
 171          *
 172          * @param $conditions Array
 173          * @return Revision or null
 174          */
 175         public static function newFromConds( $conditions ) {
 176                 $db = wfGetDB( DB_SLAVE );
 177                 $row = Revision::loadFromConds( $db, $conditions );
 178                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 179                         $dbw = wfGetDB( DB_MASTER );
 180                         $row = Revision::loadFromConds( $dbw, $conditions );
 181                 }
 182                 return $row;
 183         }
 184
 185         /**
 186          * Given a set of conditions, fetch a revision from
 187          * the given database connection.
 188          *
 189          * @param $db Database
 190          * @param $conditions Array
 191          * @return Revision or null
 192          */
 193         private static function loadFromConds( $db, $conditions ) {
 194                 $res = Revision::fetchFromConds( $db, $conditions );
 195                 if( $res ) {
 196                         $row = $res->fetchObject();
 197                         $res->free();
 198                         if( $row ) {
 199                                 $ret = new Revision( $row );
 200                                 return $ret;
 201                         }
 202                 }
 203                 $ret = null;
 204                 return $ret;
 205         }
 206
 207         /**
 208          * Return a wrapper for a series of database rows to
 209          * fetch all of a given page's revisions in turn.
 210          * Each row can be fed to the constructor to get objects.
 211          *
 212          * @param $title Title
 213          * @return ResultWrapper
 214          */
 215         public static function fetchRevision( $title ) {
 216                 return Revision::fetchFromConds(
 217                         wfGetDB( DB_SLAVE ),
 218                         array( 'rev_id=page_latest',
 219                                'page_namespace' => $title->getNamespace(),
 220                                'page_title'     => $title->getDBkey(),
 221                                'page_id=rev_page' ) );
 222         }
 223
 224         /**
 225          * Given a set of conditions, return a ResultWrapper
 226          * which will return matching database rows with the
 227          * fields necessary to build Revision objects.
 228          *
 229          * @param $db Database
 230          * @param $conditions Array
 231          * @return ResultWrapper
 232          */
 233         private static function fetchFromConds( $db, $conditions ) {
 234                 $fields = self::selectFields();
 235                 $fields[] = 'page_namespace';
 236                 $fields[] = 'page_title';
 237                 $fields[] = 'page_latest';
 238                 $res = $db->select(
 239                         array( 'page', 'revision' ),
 240                         $fields,
 241                         $conditions,
 242                         __METHOD__,
 243                         array( 'LIMIT' => 1 ) );
 244                 $ret = $db->resultObject( $res );
 245                 return $ret;
 246         }
 247
 248         /**
 249          * Return the list of revision fields that should be selected to create
 250          * a new revision.
 251          */
 252         public static function selectFields() {
 253                 return array(
 254                         'rev_id',
 255                         'rev_page',
 256                         'rev_text_id',
 257                         'rev_timestamp',
 258                         'rev_comment',
 259                         'rev_user_text,'.
 260                         'rev_user',
 261                         'rev_minor_edit',
 262                         'rev_deleted',
 263                         'rev_len',
 264                         'rev_parent_id'
 265                 );
 266         }
 267
 268         /**
 269          * Return the list of text fields that should be selected to read the
 270          * revision text
 271          */
 272         static function selectTextFields() {
 273                 return array(
 274                         'old_text',
 275                         'old_flags'
 276                 );
 277         }
 278
 279         /**
 280          * Return the list of page fields that should be selected from page table
 281          */
 282         static function selectPageFields() {
 283                 return array(
 284                         'page_namespace',
 285                         'page_title',
 286                         'page_latest'
 287                 );
 288         }
 289
 290         /**
 291          * Constructor
 292          *
 293          * @param $row Mixed: either a database row or an array
 294          * @access private
 295          */
 296         function __construct( $row ) {
 297                 if( is_object( $row ) ) {
 298                         $this->mId        = intval( $row->rev_id );
 299                         $this->mPage      = intval( $row->rev_page );
 300                         $this->mTextId    = intval( $row->rev_text_id );
 301                         $this->mComment   =         $row->rev_comment;
 302                         $this->mUserText  =         $row->rev_user_text;
 303                         $this->mUser      = intval( $row->rev_user );
 304                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 305                         $this->mTimestamp =         $row->rev_timestamp;
 306                         $this->mDeleted   = intval( $row->rev_deleted );
 307
 308                         if( !isset( $row->rev_parent_id ) )
 309                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 310                         else
 311                                 $this->mParentId  = intval( $row->rev_parent_id );
 312
 313                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 314                                 $this->mSize = null;
 315                         else
 316                                 $this->mSize = intval( $row->rev_len );
 317
 318                         if( isset( $row->page_latest ) ) {
 319                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 320                                 $this->mTitle = Title::newFromRow( $row );
 321                         } else {
 322                                 $this->mCurrent = false;
 323                                 $this->mTitle = null;
 324                         }
 325
 326                         // Lazy extraction...
 327                         $this->mText      = null;
 328                         if( isset( $row->old_text ) ) {
 329                                 $this->mTextRow = $row;
 330                         } else {
 331                                 // 'text' table row entry will be lazy-loaded
 332                                 $this->mTextRow = null;
 333                         }
 334                 } elseif( is_array( $row ) ) {
 335                         // Build a new revision to be saved...
 336                         global $wgUser;
 337
 338                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 339                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 340                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 341                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 342                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 343                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 344                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 345                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 346                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 347                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 348
 349                         // Enforce spacing trimming on supplied text
 350                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 351                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 352                         $this->mTextRow   = null;
 353
 354                         $this->mTitle     = null; # Load on demand if needed
 355                         $this->mCurrent   = false;
 356                         # If we still have no len_size, see it we have the text to figure it out
 357                         if ( !$this->mSize )
 358                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 359                 } else {
 360                         throw new MWException( 'Revision constructor passed invalid row format.' );
 361                 }
 362                 $this->mUnpatrolled = null;
 363         }
 364
 365         /**
 366          * Get revision ID
 367          *
 368          * @return Integer
 369          */
 370         public function getId() {
 371                 return $this->mId;
 372         }
 373
 374         /**
 375          * Get text row ID
 376          *
 377          * @return Integer
 378          */
 379         public function getTextId() {
 380                 return $this->mTextId;
 381         }
 382
 383         /**
 384          * Get parent revision ID (the original previous page revision)
 385          *
 386          * @return Integer
 387          */
 388         public function getParentId() {
 389                 return $this->mParentId;
 390         }
 391
 392         /**
 393          * Returns the length of the text in this revision, or null if unknown.
 394          *
 395          * @return Integer
 396          */
 397         public function getSize() {
 398                 return $this->mSize;
 399         }
 400
 401         /**
 402          * Returns the title of the page associated with this entry.
 403          *
 404          * @return Title
 405          */
 406         public function getTitle() {
 407                 if( isset( $this->mTitle ) ) {
 408                         return $this->mTitle;
 409                 }
 410                 $dbr = wfGetDB( DB_SLAVE );
 411                 $row = $dbr->selectRow(
 412                         array( 'page', 'revision' ),
 413                         array( 'page_namespace', 'page_title' ),
 414                         array( 'page_id=rev_page',
 415                                'rev_id' => $this->mId ),
 416                         'Revision::getTitle' );
 417                 if( $row ) {
 418                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 419                                                           $row->page_title );
 420                 }
 421                 return $this->mTitle;
 422         }
 423
 424         /**
 425          * Set the title of the revision
 426          *
 427          * @param $title Title
 428          */
 429         public function setTitle( $title ) {
 430                 $this->mTitle = $title;
 431         }
 432
 433         /**
 434          * Get the page ID
 435          *
 436          * @return Integer
 437          */
 438         public function getPage() {
 439                 return $this->mPage;
 440         }
 441
 442         /**
 443          * Fetch revision's user id if it's available to the specified audience.
 444          * If the specified audience does not have access to it, zero will be
 445          * returned.
 446          *
 447          * @param $audience Integer: one of:
 448          *      Revision::FOR_PUBLIC       to be displayed to all users
 449          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 450          *      Revision::RAW              get the ID regardless of permissions
 451          *
 452          *
 453          * @return Integer
 454          */
 455         public function getUser( $audience = self::FOR_PUBLIC ) {
 456                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 457                         return 0;
 458                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 459                         return 0;
 460                 } else {
 461                         return $this->mUser;
 462                 }
 463         }
 464
 465         /**
 466          * Fetch revision's user id without regard for the current user's permissions
 467          *
 468          * @return String
 469          */
 470         public function getRawUser() {
 471                 return $this->mUser;
 472         }
 473
 474         /**
 475          * Fetch revision's username if it's available to the specified audience.
 476          * If the specified audience does not have access to the username, an
 477          * empty string will be returned.
 478          *
 479          * @param $audience Integer: one of:
 480          *      Revision::FOR_PUBLIC       to be displayed to all users
 481          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 482          *      Revision::RAW              get the text regardless of permissions
 483          *
 484          * @return string
 485          */
 486         public function getUserText( $audience = self::FOR_PUBLIC ) {
 487                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 488                         return '';
 489                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 490                         return '';
 491                 } else {
 492                         return $this->mUserText;
 493                 }
 494         }
 495
 496         /**
 497          * Fetch revision's username without regard for view restrictions
 498          *
 499          * @return String
 500          */
 501         public function getRawUserText() {
 502                 return $this->mUserText;
 503         }
 504
 505         /**
 506          * Fetch revision comment if it's available to the specified audience.
 507          * If the specified audience does not have access to the comment, an
 508          * empty string will be returned.
 509          *
 510          * @param $audience Integer: one of:
 511          *      Revision::FOR_PUBLIC       to be displayed to all users
 512          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 513          *      Revision::RAW              get the text regardless of permissions
 514          *
 515          * @return String
 516          */
 517         function getComment( $audience = self::FOR_PUBLIC ) {
 518                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 519                         return '';
 520                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 521                         return '';
 522                 } else {
 523                         return $this->mComment;
 524                 }
 525         }
 526
 527         /**
 528          * Fetch revision comment without regard for the current user's permissions
 529          *
 530          * @return String
 531          */
 532         public function getRawComment() {
 533                 return $this->mComment;
 534         }
 535
 536         /**
 537          * @return Boolean
 538          */
 539         public function isMinor() {
 540                 return (bool)$this->mMinorEdit;
 541         }
 542
 543         /**
 544          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 545          */
 546         public function isUnpatrolled() {
 547                 if( $this->mUnpatrolled !== null ) {
 548                         return $this->mUnpatrolled;
 549                 }
 550                 $dbr = wfGetDB( DB_SLAVE );
 551                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 552                         'rc_id',
 553                         array( // Add redundant user,timestamp condition so we can use the existing index
 554                                 'rc_user_text'  => $this->getRawUserText(),
 555                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 556                                 'rc_this_oldid' => $this->getId(),
 557                                 'rc_patrolled'  => 0
 558                         ),
 559                         __METHOD__
 560                 );
 561                 return (int)$this->mUnpatrolled;
 562         }
 563
 564         /**
 565          * int $field one of DELETED_* bitfield constants
 566          *
 567          * @return Boolean
 568          */
 569         public function isDeleted( $field ) {
 570                 return ( $this->mDeleted & $field ) == $field;
 571         }
 572
 573         /**
 574          * Get the deletion bitfield of the revision
 575          */
 576         public function getVisibility() {
 577                 return (int)$this->mDeleted;
 578         }
 579
 580         /**
 581          * Fetch revision text if it's available to the specified audience.
 582          * If the specified audience does not have the ability to view this
 583          * revision, an empty string will be returned.
 584          *
 585          * @param $audience Integer: one of:
 586          *      Revision::FOR_PUBLIC       to be displayed to all users
 587          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 588          *      Revision::RAW              get the text regardless of permissions
 589          *
 590          *
 591          * @return String
 592          */
 593         public function getText( $audience = self::FOR_PUBLIC ) {
 594                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 595                         return '';
 596                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 597                         return '';
 598                 } else {
 599                         return $this->getRawText();
 600                 }
 601         }
 602
 603         /**
 604          * Alias for getText(Revision::FOR_THIS_USER)
 605          *
 606          * @deprecated
 607          * @return String
 608          */
 609         public function revText() {
 610                 wfDeprecated();
 611                 return $this->getText( self::FOR_THIS_USER );
 612         }
 613
 614         /**
 615          * Fetch revision text without regard for view restrictions
 616          *
 617          * @return String
 618          */
 619         public function getRawText() {
 620                 if( is_null( $this->mText ) ) {
 621                         // Revision text is immutable. Load on demand:
 622                         $this->mText = $this->loadText();
 623                 }
 624                 return $this->mText;
 625         }
 626
 627         /**
 628          * @return String
 629          */
 630         public function getTimestamp() {
 631                 return wfTimestamp( TS_MW, $this->mTimestamp );
 632         }
 633
 634         /**
 635          * @return Boolean
 636          */
 637         public function isCurrent() {
 638                 return $this->mCurrent;
 639         }
 640
 641         /**
 642          * Get previous revision for this title
 643          *
 644          * @return Revision or null
 645          */
 646         public function getPrevious() {
 647                 if( $this->getTitle() ) {
 648                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 649                         if( $prev ) {
 650                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 651                         }
 652                 }
 653                 return null;
 654         }
 655
 656         /**
 657          * Get next revision for this title
 658          *
 659          * @return Revision or null
 660          */
 661         public function getNext() {
 662                 if( $this->getTitle() ) {
 663                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 664                         if ( $next ) {
 665                                 return Revision::newFromTitle( $this->getTitle(), $next );
 666                         }
 667                 }
 668                 return null;
 669         }
 670
 671         /**
 672          * Get previous revision Id for this page_id
 673          * This is used to populate rev_parent_id on save
 674          *
 675          * @param $db DatabaseBase
 676          * @return Integer
 677          */
 678         private function getPreviousRevisionId( $db ) {
 679                 if( is_null( $this->mPage ) ) {
 680                         return 0;
 681                 }
 682                 # Use page_latest if ID is not given
 683                 if( !$this->mId ) {
 684                         $prevId = $db->selectField( 'page', 'page_latest',
 685                                 array( 'page_id' => $this->mPage ),
 686                                 __METHOD__ );
 687                 } else {
 688                         $prevId = $db->selectField( 'revision', 'rev_id',
 689                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 690                                 __METHOD__,
 691                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 692                 }
 693                 return intval( $prevId );
 694         }
 695
 696         /**
 697           * Get revision text associated with an old or archive row
 698           * $row is usually an object from wfFetchRow(), both the flags and the text
 699           * field must be included
 700           *
 701           * @param $row Object: the text data
 702           * @param $prefix String: table prefix (default 'old_')
 703           * @return String: text the text requested or false on failure
 704           */
 705         public static function getRevisionText( $row, $prefix = 'old_' ) {
 706                 wfProfileIn( __METHOD__ );
 707
 708                 # Get data
 709                 $textField = $prefix . 'text';
 710                 $flagsField = $prefix . 'flags';
 711
 712                 if( isset( $row->$flagsField ) ) {
 713                         $flags = explode( ',', $row->$flagsField );
 714                 } else {
 715                         $flags = array();
 716                 }
 717
 718                 if( isset( $row->$textField ) ) {
 719                         $text = $row->$textField;
 720                 } else {
 721                         wfProfileOut( __METHOD__ );
 722                         return false;
 723                 }
 724
 725                 # Use external methods for external objects, text in table is URL-only then
 726                 if ( in_array( 'external', $flags ) ) {
 727                         $url = $text;
 728                         @list(/* $proto */, $path ) = explode( '://', $url, 2 );
 729                         if( $path == '' ) {
 730                                 wfProfileOut( __METHOD__ );
 731                                 return false;
 732                         }
 733                         $text = ExternalStore::fetchFromURL( $url );
 734                 }
 735
 736                 // If the text was fetched without an error, convert it
 737                 if ( $text !== false ) {
 738                         if( in_array( 'gzip', $flags ) ) {
 739                                 # Deal with optional compression of archived pages.
 740                                 # This can be done periodically via maintenance/compressOld.php, and
 741                                 # as pages are saved if $wgCompressRevisions is set.
 742                                 $text = gzinflate( $text );
 743                         }
 744
 745                         if( in_array( 'object', $flags ) ) {
 746                                 # Generic compressed storage
 747                                 $obj = unserialize( $text );
 748                                 if ( !is_object( $obj ) ) {
 749                                         // Invalid object
 750                                         wfProfileOut( __METHOD__ );
 751                                         return false;
 752                                 }
 753                                 $text = $obj->getText();
 754                         }
 755
 756                         global $wgLegacyEncoding;
 757                         if( $text !== false && $wgLegacyEncoding
 758                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 759                         {
 760                                 # Old revisions kept around in a legacy encoding?
 761                                 # Upconvert on demand.
 762                                 # ("utf8" checked for compatibility with some broken
 763                                 #  conversion scripts 2008-12-30)
 764                                 global $wgInputEncoding, $wgContLang;
 765                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 766                         }
 767                 }
 768                 wfProfileOut( __METHOD__ );
 769                 return $text;
 770         }
 771
 772         /**
 773          * If $wgCompressRevisions is enabled, we will compress data.
 774          * The input string is modified in place.
 775          * Return value is the flags field: contains 'gzip' if the
 776          * data is compressed, and 'utf-8' if we're saving in UTF-8
 777          * mode.
 778          *
 779          * @param $text Mixed: reference to a text
 780          * @return String
 781          */
 782         public static function compressRevisionText( &$text ) {
 783                 global $wgCompressRevisions;
 784                 $flags = array();
 785
 786                 # Revisions not marked this way will be converted
 787                 # on load if $wgLegacyCharset is set in the future.
 788                 $flags[] = 'utf-8';
 789
 790                 if( $wgCompressRevisions ) {
 791                         if( function_exists( 'gzdeflate' ) ) {
 792                                 $text = gzdeflate( $text );
 793                                 $flags[] = 'gzip';
 794                         } else {
 795                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 796                         }
 797                 }
 798                 return implode( ',', $flags );
 799         }
 800
 801         /**
 802          * Insert a new revision into the database, returning the new revision ID
 803          * number on success and dies horribly on failure.
 804          *
 805          * @param $dbw DatabaseBase: (master connection)
 806          * @return Integer
 807          */
 808         public function insertOn( $dbw ) {
 809                 global $wgDefaultExternalStore;
 810
 811                 wfProfileIn( __METHOD__ );
 812
 813                 $data = $this->mText;
 814                 $flags = Revision::compressRevisionText( $data );
 815
 816                 # Write to external storage if required
 817                 if( $wgDefaultExternalStore ) {
 818                         // Store and get the URL
 819                         $data = ExternalStore::insertToDefault( $data );
 820                         if( !$data ) {
 821                                 throw new MWException( "Unable to store text to external storage" );
 822                         }
 823                         if( $flags ) {
 824                                 $flags .= ',';
 825                         }
 826                         $flags .= 'external';
 827                 }
 828
 829                 # Record the text (or external storage URL) to the text table
 830                 if( !isset( $this->mTextId ) ) {
 831                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 832                         $dbw->insert( 'text',
 833                                 array(
 834                                         'old_id'    => $old_id,
 835                                         'old_text'  => $data,
 836                                         'old_flags' => $flags,
 837                                 ), __METHOD__
 838                         );
 839                         $this->mTextId = $dbw->insertId();
 840                 }
 841
 842                 if ( $this->mComment === null ) $this->mComment = "";
 843
 844                 # Record the edit in revisions
 845                 $rev_id = isset( $this->mId )
 846                         ? $this->mId
 847                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 848                 $dbw->insert( 'revision',
 849                         array(
 850                                 'rev_id'         => $rev_id,
 851                                 'rev_page'       => $this->mPage,
 852                                 'rev_text_id'    => $this->mTextId,
 853                                 'rev_comment'    => $this->mComment,
 854                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 855                                 'rev_user'       => $this->mUser,
 856                                 'rev_user_text'  => $this->mUserText,
 857                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 858                                 'rev_deleted'    => $this->mDeleted,
 859                                 'rev_len'        => $this->mSize,
 860                                 'rev_parent_id'  => is_null($this->mParentId) ?
 861                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 862                         ), __METHOD__
 863                 );
 864
 865                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 866
 867                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 868
 869                 wfProfileOut( __METHOD__ );
 870                 return $this->mId;
 871         }
 872
 873         /**
 874          * Lazy-load the revision's text.
 875          * Currently hardcoded to the 'text' table storage engine.
 876          *
 877          * @return String
 878          */
 879         protected function loadText() {
 880                 wfProfileIn( __METHOD__ );
 881
 882                 // Caching may be beneficial for massive use of external storage
 883                 global $wgRevisionCacheExpiry, $wgMemc;
 884                 $textId = $this->getTextId();
 885                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 886                 if( $wgRevisionCacheExpiry ) {
 887                         $text = $wgMemc->get( $key );
 888                         if( is_string( $text ) ) {
 889                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 890                                 wfProfileOut( __METHOD__ );
 891                                 return $text;
 892                         }
 893                 }
 894
 895                 // If we kept data for lazy extraction, use it now...
 896                 if ( isset( $this->mTextRow ) ) {
 897                         $row = $this->mTextRow;
 898                         $this->mTextRow = null;
 899                 } else {
 900                         $row = null;
 901                 }
 902
 903                 if( !$row ) {
 904                         // Text data is immutable; check slaves first.
 905                         $dbr = wfGetDB( DB_SLAVE );
 906                         $row = $dbr->selectRow( 'text',
 907                                 array( 'old_text', 'old_flags' ),
 908                                 array( 'old_id' => $this->getTextId() ),
 909                                 __METHOD__ );
 910                 }
 911
 912                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 913                         // Possible slave lag!
 914                         $dbw = wfGetDB( DB_MASTER );
 915                         $row = $dbw->selectRow( 'text',
 916                                 array( 'old_text', 'old_flags' ),
 917                                 array( 'old_id' => $this->getTextId() ),
 918                                 __METHOD__ );
 919                 }
 920
 921                 $text = self::getRevisionText( $row );
 922
 923                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 924                 if( $wgRevisionCacheExpiry && $text !== false ) {
 925                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 926                 }
 927
 928                 wfProfileOut( __METHOD__ );
 929
 930                 return $text;
 931         }
 932
 933         /**
 934          * Create a new null-revision for insertion into a page's
 935          * history. This will not re-save the text, but simply refer
 936          * to the text from the previous version.
 937          *
 938          * Such revisions can for instance identify page rename
 939          * operations and other such meta-modifications.
 940          *
 941          * @param $dbw DatabaseBase
 942          * @param $pageId Integer: ID number of the page to read from
 943          * @param $summary String: revision's summary
 944          * @param $minor Boolean: whether the revision should be considered as minor
 945          * @return Mixed: Revision, or null on error
 946          */
 947         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 948                 wfProfileIn( __METHOD__ );
 949
 950                 $current = $dbw->selectRow(
 951                         array( 'page', 'revision' ),
 952                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 953                         array(
 954                                 'page_id' => $pageId,
 955                                 'page_latest=rev_id',
 956                                 ),
 957                         __METHOD__ );
 958
 959                 if( $current ) {
 960                         $revision = new Revision( array(
 961                                 'page'       => $pageId,
 962                                 'comment'    => $summary,
 963                                 'minor_edit' => $minor,
 964                                 'text_id'    => $current->rev_text_id,
 965                                 'parent_id'  => $current->page_latest,
 966                                 'len'        => $current->rev_len
 967                                 ) );
 968                 } else {
 969                         $revision = null;
 970                 }
 971
 972                 wfProfileOut( __METHOD__ );
 973                 return $revision;
 974         }
 975
 976         /**
 977          * Determine if the current user is allowed to view a particular
 978          * field of this revision, if it's marked as deleted.
 979          *
 980          * @param $field Integer:one of self::DELETED_TEXT,
 981          *                              self::DELETED_COMMENT,
 982          *                              self::DELETED_USER
 983          * @return Boolean
 984          */
 985         public function userCan( $field ) {
 986                 return self::userCanBitfield( $this->mDeleted, $field );
 987         }
 988
 989         /**
 990          * Determine if the current user is allowed to view a particular
 991          * field of this revision, if it's marked as deleted. This is used
 992          * by various classes to avoid duplication.
 993          *
 994          * @param $bitfield Integer: current field
 995          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
 996          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
 997          *                               self::DELETED_USER = File::DELETED_USER
 998          * @return Boolean
 999          */
1000         public static function userCanBitfield( $bitfield, $field ) {
1001                 if( $bitfield & $field ) { // aspect is deleted
1002                         global $wgUser;
1003                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1004                                 $permission = 'suppressrevision';
1005                         } elseif ( $field & self::DELETED_TEXT ) {
1006                                 $permission = 'deletedtext';
1007                         } else {
1008                                 $permission = 'deletedhistory';
1009                         }
1010                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1011                         return $wgUser->isAllowed( $permission );
1012                 } else {
1013                         return true;
1014                 }
1015         }
1016
1017         /**
1018          * Get rev_timestamp from rev_id, without loading the rest of the row
1019          *
1020          * @param $title Title
1021          * @param $id Integer
1022          * @return String
1023          */
1024         static function getTimestampFromId( $title, $id ) {
1025                 $dbr = wfGetDB( DB_SLAVE );
1026                 // Casting fix for DB2
1027                 if ( $id == '' ) {
1028                         $id = 0;
1029                 }
1030                 $conds = array( 'rev_id' => $id );
1031                 $conds['rev_page'] = $title->getArticleId();
1032                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1033                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1034                         # Not in slave, try master
1035                         $dbw = wfGetDB( DB_MASTER );
1036                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1037                 }
1038                 return wfTimestamp( TS_MW, $timestamp );
1039         }
1040
1041         /**
1042          * Get count of revisions per page...not very efficient
1043          *
1044          * @param $db DatabaseBase
1045          * @param $id Integer: page id
1046          * @return Integer
1047          */
1048         static function countByPageId( $db, $id ) {
1049                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1050                         array( 'rev_page' => $id ), __METHOD__ );
1051                 if( $row ) {
1052                         return $row->revCount;
1053                 }
1054                 return 0;
1055         }
1056
1057         /**
1058          * Get count of revisions per page...not very efficient
1059          *
1060          * @param $db DatabaseBase
1061          * @param $title Title
1062          * @return Integer
1063          */
1064         static function countByTitle( $db, $title ) {
1065                 $id = $title->getArticleId();
1066                 if( $id ) {
1067                         return Revision::countByPageId( $db, $id );
1068                 }
1069                 return 0;
1070         }
1071 }
1072
1073 /**
1074  * Aliases for backwards compatibility with 1.6
1075  */
1076 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1077 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1078 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1079 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );