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 (optional)
  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                                 return null; // page does not exist
  54                         }
  55                         $conds['rev_id'] = $latest;
  56                 } else {
  57                         // Use a join to get the latest revision
  58                         $conds[] = 'rev_id=page_latest';
  59                 }
  60                 $conds[] = 'page_id=rev_page';
  61                 return Revision::newFromConds( $conds );
  62         }
  63
  64         /**
  65          * Load either the current, or a specified, revision
  66          * that's attached to a given page ID.
  67          * Returns null if no such revision can be found.
  68          *
  69          * @param $revId Integer
  70          * @param $pageId Integer (optional)
  71          * @return Revision or null
  72          */
  73         public static function newFromPageId( $pageId, $revId = 0 ) {
  74                 $conds = array( 'page_id' => $pageId );
  75                 if ( $revId ) {
  76                         $conds['rev_id'] = $pageId;
  77                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  78                         // Get the latest revision ID from the master
  79                         $dbw = wfGetDB( DB_MASTER );
  80                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  81                         if ( $latest === false ) {
  82                                 return null; // page does not exist
  83                         }
  84                         $conds['rev_id'] = $latest;
  85                 } else {
  86                         $conds[] = 'rev_id = page_latest';
  87                 }
  88                 return Revision::newFromConds( $conds );
  89         }
  90
  91         /**
  92          * Make a fake revision object from an archive table row. This is queried
  93          * for permissions or even inserted (as in Special:Undelete)
  94          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
  95          *
  96          * @param $row
  97          * @param $overrides array
  98          *
  99          * @return Revision
 100          */
 101         public static function newFromArchiveRow( $row, $overrides = array() ) {
 102                 $attribs = $overrides + array(
 103                         'page'       => isset( $row->page_id ) ? $row->page_id : null,
 104                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 105                         'comment'    => $row->ar_comment,
 106                         'user'       => $row->ar_user,
 107                         'user_text'  => $row->ar_user_text,
 108                         'timestamp'  => $row->ar_timestamp,
 109                         'minor_edit' => $row->ar_minor_edit,
 110                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 111                         'deleted'    => $row->ar_deleted,
 112                         'len'        => $row->ar_len);
 113                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 114                         // Pre-1.5 ar_text row
 115                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 116                         if ( $attribs['text'] === false ) {
 117                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 118                         }
 119                 }
 120                 return new self( $attribs );
 121         }
 122
 123         /**
 124          * Load a page revision from a given revision ID number.
 125          * Returns null if no such revision can be found.
 126          *
 127          * @param $db DatabaseBase
 128          * @param $id Integer
 129          * @return Revision or null
 130          */
 131         public static function loadFromId( $db, $id ) {
 132                 return Revision::loadFromConds( $db,
 133                         array( 'page_id=rev_page',
 134                                    'rev_id' => intval( $id ) ) );
 135         }
 136
 137         /**
 138          * Load either the current, or a specified, revision
 139          * that's attached to a given page. If not attached
 140          * to that page, will return null.
 141          *
 142          * @param $db DatabaseBase
 143          * @param $pageid Integer
 144          * @param $id Integer
 145          * @return Revision or null
 146          */
 147         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 148                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 149                 if( $id ) {
 150                         $conds['rev_id'] = intval( $id );
 151                 } else {
 152                         $conds[] = 'rev_id=page_latest';
 153                 }
 154                 return Revision::loadFromConds( $db, $conds );
 155         }
 156
 157         /**
 158          * Load either the current, or a specified, revision
 159          * that's attached to a given page. If not attached
 160          * to that page, will return null.
 161          *
 162          * @param $db DatabaseBase
 163          * @param $title Title
 164          * @param $id Integer
 165          * @return Revision or null
 166          */
 167         public static function loadFromTitle( $db, $title, $id = 0 ) {
 168                 if( $id ) {
 169                         $matchId = intval( $id );
 170                 } else {
 171                         $matchId = 'page_latest';
 172                 }
 173                 return Revision::loadFromConds(
 174                         $db,
 175                         array( "rev_id=$matchId",
 176                                    'page_id=rev_page',
 177                                    'page_namespace' => $title->getNamespace(),
 178                                    'page_title'     => $title->getDBkey() ) );
 179         }
 180
 181         /**
 182          * Load the revision for the given title with the given timestamp.
 183          * WARNING: Timestamps may in some circumstances not be unique,
 184          * so this isn't the best key to use.
 185          *
 186          * @param $db DatabaseBase
 187          * @param $title Title
 188          * @param $timestamp String
 189          * @return Revision or null
 190          */
 191         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 192                 return Revision::loadFromConds(
 193                         $db,
 194                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 195                                    'page_id=rev_page',
 196                                    'page_namespace' => $title->getNamespace(),
 197                                    'page_title'     => $title->getDBkey() ) );
 198         }
 199
 200         /**
 201          * Given a set of conditions, fetch a revision.
 202          *
 203          * @param $conditions Array
 204          * @return Revision or null
 205          */
 206         public static function newFromConds( $conditions ) {
 207                 $db = wfGetDB( DB_SLAVE );
 208                 $row = Revision::loadFromConds( $db, $conditions );
 209                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 210                         $dbw = wfGetDB( DB_MASTER );
 211                         $row = Revision::loadFromConds( $dbw, $conditions );
 212                 }
 213                 return $row;
 214         }
 215
 216         /**
 217          * Given a set of conditions, fetch a revision from
 218          * the given database connection.
 219          *
 220          * @param $db DatabaseBase
 221          * @param $conditions Array
 222          * @return Revision or null
 223          */
 224         private static function loadFromConds( $db, $conditions ) {
 225                 $res = Revision::fetchFromConds( $db, $conditions );
 226                 if( $res ) {
 227                         $row = $res->fetchObject();
 228                         $res->free();
 229                         if( $row ) {
 230                                 $ret = new Revision( $row );
 231                                 return $ret;
 232                         }
 233                 }
 234                 $ret = null;
 235                 return $ret;
 236         }
 237
 238         /**
 239          * Return a wrapper for a series of database rows to
 240          * fetch all of a given page's revisions in turn.
 241          * Each row can be fed to the constructor to get objects.
 242          *
 243          * @param $title Title
 244          * @return ResultWrapper
 245          */
 246         public static function fetchRevision( $title ) {
 247                 return Revision::fetchFromConds(
 248                         wfGetDB( DB_SLAVE ),
 249                         array( 'rev_id=page_latest',
 250                                    'page_namespace' => $title->getNamespace(),
 251                                    'page_title'     => $title->getDBkey(),
 252                                    'page_id=rev_page' ) );
 253         }
 254
 255         /**
 256          * Given a set of conditions, return a ResultWrapper
 257          * which will return matching database rows with the
 258          * fields necessary to build Revision objects.
 259          *
 260          * @param $db DatabaseBase
 261          * @param $conditions Array
 262          * @return ResultWrapper
 263          */
 264         private static function fetchFromConds( $db, $conditions ) {
 265                 $fields = self::selectFields();
 266                 $fields[] = 'page_namespace';
 267                 $fields[] = 'page_title';
 268                 $fields[] = 'page_latest';
 269                 return $db->select(
 270                         array( 'page', 'revision' ),
 271                         $fields,
 272                         $conditions,
 273                         __METHOD__,
 274                         array( 'LIMIT' => 1 ) );
 275         }
 276
 277         /**
 278          * Return the list of revision fields that should be selected to create
 279          * a new revision.
 280          */
 281         public static function selectFields() {
 282                 return array(
 283                         'rev_id',
 284                         'rev_page',
 285                         'rev_text_id',
 286                         'rev_timestamp',
 287                         'rev_comment',
 288                         'rev_user_text,'.
 289                         'rev_user',
 290                         'rev_minor_edit',
 291                         'rev_deleted',
 292                         'rev_len',
 293                         'rev_parent_id'
 294                 );
 295         }
 296
 297         /**
 298          * Return the list of text fields that should be selected to read the
 299          * revision text
 300          */
 301         static function selectTextFields() {
 302                 return array(
 303                         'old_text',
 304                         'old_flags'
 305                 );
 306         }
 307
 308         /**
 309          * Return the list of page fields that should be selected from page table
 310          */
 311         static function selectPageFields() {
 312                 return array(
 313                         'page_namespace',
 314                         'page_title',
 315                         'page_latest'
 316                 );
 317         }
 318
 319         /**
 320          * Constructor
 321          *
 322          * @param $row Mixed: either a database row or an array
 323          * @access private
 324          */
 325         function __construct( $row ) {
 326                 if( is_object( $row ) ) {
 327                         $this->mId        = intval( $row->rev_id );
 328                         $this->mPage      = intval( $row->rev_page );
 329                         $this->mTextId    = intval( $row->rev_text_id );
 330                         $this->mComment   =         $row->rev_comment;
 331                         $this->mUserText  =         $row->rev_user_text;
 332                         $this->mUser      = intval( $row->rev_user );
 333                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 334                         $this->mTimestamp =         $row->rev_timestamp;
 335                         $this->mDeleted   = intval( $row->rev_deleted );
 336
 337                         if( !isset( $row->rev_parent_id ) )
 338                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 339                         else
 340                                 $this->mParentId  = intval( $row->rev_parent_id );
 341
 342                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 343                                 $this->mSize = null;
 344                         else
 345                                 $this->mSize = intval( $row->rev_len );
 346
 347                         if( isset( $row->page_latest ) ) {
 348                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 349                                 $this->mTitle = Title::newFromRow( $row );
 350                         } else {
 351                                 $this->mCurrent = false;
 352                                 $this->mTitle = null;
 353                         }
 354
 355                         // Lazy extraction...
 356                         $this->mText      = null;
 357                         if( isset( $row->old_text ) ) {
 358                                 $this->mTextRow = $row;
 359                         } else {
 360                                 // 'text' table row entry will be lazy-loaded
 361                                 $this->mTextRow = null;
 362                         }
 363                 } elseif( is_array( $row ) ) {
 364                         // Build a new revision to be saved...
 365                         global $wgUser;
 366
 367                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 368                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 369                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 370                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 371                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 372                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 373                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 374                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 375                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 376                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 377
 378                         // Enforce spacing trimming on supplied text
 379                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 380                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 381                         $this->mTextRow   = null;
 382
 383                         $this->mTitle     = null; # Load on demand if needed
 384                         $this->mCurrent   = false;
 385                         # If we still have no len_size, see it we have the text to figure it out
 386                         if ( !$this->mSize )
 387                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 388                 } else {
 389                         throw new MWException( 'Revision constructor passed invalid row format.' );
 390                 }
 391                 $this->mUnpatrolled = null;
 392         }
 393
 394         /**
 395          * Get revision ID
 396          *
 397          * @return Integer
 398          */
 399         public function getId() {
 400                 return $this->mId;
 401         }
 402
 403         /**
 404          * Get text row ID
 405          *
 406          * @return Integer
 407          */
 408         public function getTextId() {
 409                 return $this->mTextId;
 410         }
 411
 412         /**
 413          * Get parent revision ID (the original previous page revision)
 414          *
 415          * @return Integer
 416          */
 417         public function getParentId() {
 418                 return $this->mParentId;
 419         }
 420
 421         /**
 422          * Returns the length of the text in this revision, or null if unknown.
 423          *
 424          * @return Integer
 425          */
 426         public function getSize() {
 427                 return $this->mSize;
 428         }
 429
 430         /**
 431          * Returns the title of the page associated with this entry.
 432          *
 433          * @return Title
 434          */
 435         public function getTitle() {
 436                 if( isset( $this->mTitle ) ) {
 437                         return $this->mTitle;
 438                 }
 439                 $dbr = wfGetDB( DB_SLAVE );
 440                 $row = $dbr->selectRow(
 441                         array( 'page', 'revision' ),
 442                         array( 'page_namespace', 'page_title' ),
 443                         array( 'page_id=rev_page',
 444                                    'rev_id' => $this->mId ),
 445                         'Revision::getTitle' );
 446                 if( $row ) {
 447                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 448                                                                                           $row->page_title );
 449                 }
 450                 return $this->mTitle;
 451         }
 452
 453         /**
 454          * Set the title of the revision
 455          *
 456          * @param $title Title
 457          */
 458         public function setTitle( $title ) {
 459                 $this->mTitle = $title;
 460         }
 461
 462         /**
 463          * Get the page ID
 464          *
 465          * @return Integer
 466          */
 467         public function getPage() {
 468                 return $this->mPage;
 469         }
 470
 471         /**
 472          * Fetch revision's user id if it's available to the specified audience.
 473          * If the specified audience does not have access to it, zero will be
 474          * returned.
 475          *
 476          * @param $audience Integer: one of:
 477          *      Revision::FOR_PUBLIC       to be displayed to all users
 478          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 479          *      Revision::RAW              get the ID regardless of permissions
 480          *
 481          *
 482          * @return Integer
 483          */
 484         public function getUser( $audience = self::FOR_PUBLIC ) {
 485                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 486                         return 0;
 487                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 488                         return 0;
 489                 } else {
 490                         return $this->mUser;
 491                 }
 492         }
 493
 494         /**
 495          * Fetch revision's user id without regard for the current user's permissions
 496          *
 497          * @return String
 498          */
 499         public function getRawUser() {
 500                 return $this->mUser;
 501         }
 502
 503         /**
 504          * Fetch revision's username if it's available to the specified audience.
 505          * If the specified audience does not have access to the username, an
 506          * empty string will be returned.
 507          *
 508          * @param $audience Integer: one of:
 509          *      Revision::FOR_PUBLIC       to be displayed to all users
 510          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 511          *      Revision::RAW              get the text regardless of permissions
 512          *
 513          * @return string
 514          */
 515         public function getUserText( $audience = self::FOR_PUBLIC ) {
 516                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 517                         return '';
 518                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 519                         return '';
 520                 } else {
 521                         return $this->mUserText;
 522                 }
 523         }
 524
 525         /**
 526          * Fetch revision's username without regard for view restrictions
 527          *
 528          * @return String
 529          */
 530         public function getRawUserText() {
 531                 return $this->mUserText;
 532         }
 533
 534         /**
 535          * Fetch revision comment if it's available to the specified audience.
 536          * If the specified audience does not have access to the comment, an
 537          * empty string will be returned.
 538          *
 539          * @param $audience Integer: one of:
 540          *      Revision::FOR_PUBLIC       to be displayed to all users
 541          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 542          *      Revision::RAW              get the text regardless of permissions
 543          *
 544          * @return String
 545          */
 546         function getComment( $audience = self::FOR_PUBLIC ) {
 547                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 548                         return '';
 549                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 550                         return '';
 551                 } else {
 552                         return $this->mComment;
 553                 }
 554         }
 555
 556         /**
 557          * Fetch revision comment without regard for the current user's permissions
 558          *
 559          * @return String
 560          */
 561         public function getRawComment() {
 562                 return $this->mComment;
 563         }
 564
 565         /**
 566          * @return Boolean
 567          */
 568         public function isMinor() {
 569                 return (bool)$this->mMinorEdit;
 570         }
 571
 572         /**
 573          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 574          */
 575         public function isUnpatrolled() {
 576                 if( $this->mUnpatrolled !== null ) {
 577                         return $this->mUnpatrolled;
 578                 }
 579                 $dbr = wfGetDB( DB_SLAVE );
 580                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 581                         'rc_id',
 582                         array( // Add redundant user,timestamp condition so we can use the existing index
 583                                 'rc_user_text'  => $this->getRawUserText(),
 584                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 585                                 'rc_this_oldid' => $this->getId(),
 586                                 'rc_patrolled'  => 0
 587                         ),
 588                         __METHOD__
 589                 );
 590                 return (int)$this->mUnpatrolled;
 591         }
 592
 593         /**
 594          * int $field one of DELETED_* bitfield constants
 595          *
 596          * @return Boolean
 597          */
 598         public function isDeleted( $field ) {
 599                 return ( $this->mDeleted & $field ) == $field;
 600         }
 601
 602         /**
 603          * Get the deletion bitfield of the revision
 604          */
 605         public function getVisibility() {
 606                 return (int)$this->mDeleted;
 607         }
 608
 609         /**
 610          * Fetch revision text if it's available to the specified audience.
 611          * If the specified audience does not have the ability to view this
 612          * revision, an empty string will be returned.
 613          *
 614          * @param $audience Integer: one of:
 615          *      Revision::FOR_PUBLIC       to be displayed to all users
 616          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 617          *      Revision::RAW              get the text regardless of permissions
 618          *
 619          * @return String
 620          */
 621         public function getText( $audience = self::FOR_PUBLIC ) {
 622                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 623                         return '';
 624                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 625                         return '';
 626                 } else {
 627                         return $this->getRawText();
 628                 }
 629         }
 630
 631         /**
 632          * Alias for getText(Revision::FOR_THIS_USER)
 633          *
 634          * @deprecated since 1.17
 635          * @return String
 636          */
 637         public function revText() {
 638                 wfDeprecated( __METHOD__ );
 639                 return $this->getText( self::FOR_THIS_USER );
 640         }
 641
 642         /**
 643          * Fetch revision text without regard for view restrictions
 644          *
 645          * @return String
 646          */
 647         public function getRawText() {
 648                 if( is_null( $this->mText ) ) {
 649                         // Revision text is immutable. Load on demand:
 650                         $this->mText = $this->loadText();
 651                 }
 652                 return $this->mText;
 653         }
 654
 655         /**
 656          * @return String
 657          */
 658         public function getTimestamp() {
 659                 return wfTimestamp( TS_MW, $this->mTimestamp );
 660         }
 661
 662         /**
 663          * @return Boolean
 664          */
 665         public function isCurrent() {
 666                 return $this->mCurrent;
 667         }
 668
 669         /**
 670          * Get previous revision for this title
 671          *
 672          * @return Revision or null
 673          */
 674         public function getPrevious() {
 675                 if( $this->getTitle() ) {
 676                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 677                         if( $prev ) {
 678                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 679                         }
 680                 }
 681                 return null;
 682         }
 683
 684         /**
 685          * Get next revision for this title
 686          *
 687          * @return Revision or null
 688          */
 689         public function getNext() {
 690                 if( $this->getTitle() ) {
 691                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 692                         if ( $next ) {
 693                                 return Revision::newFromTitle( $this->getTitle(), $next );
 694                         }
 695                 }
 696                 return null;
 697         }
 698
 699         /**
 700          * Get previous revision Id for this page_id
 701          * This is used to populate rev_parent_id on save
 702          *
 703          * @param $db DatabaseBase
 704          * @return Integer
 705          */
 706         private function getPreviousRevisionId( $db ) {
 707                 if( is_null( $this->mPage ) ) {
 708                         return 0;
 709                 }
 710                 # Use page_latest if ID is not given
 711                 if( !$this->mId ) {
 712                         $prevId = $db->selectField( 'page', 'page_latest',
 713                                 array( 'page_id' => $this->mPage ),
 714                                 __METHOD__ );
 715                 } else {
 716                         $prevId = $db->selectField( 'revision', 'rev_id',
 717                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 718                                 __METHOD__,
 719                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 720                 }
 721                 return intval( $prevId );
 722         }
 723
 724         /**
 725           * Get revision text associated with an old or archive row
 726           * $row is usually an object from wfFetchRow(), both the flags and the text
 727           * field must be included
 728           *
 729           * @param $row Object: the text data
 730           * @param $prefix String: table prefix (default 'old_')
 731           * @return String: text the text requested or false on failure
 732           */
 733         public static function getRevisionText( $row, $prefix = 'old_' ) {
 734                 wfProfileIn( __METHOD__ );
 735
 736                 # Get data
 737                 $textField = $prefix . 'text';
 738                 $flagsField = $prefix . 'flags';
 739
 740                 if( isset( $row->$flagsField ) ) {
 741                         $flags = explode( ',', $row->$flagsField );
 742                 } else {
 743                         $flags = array();
 744                 }
 745
 746                 if( isset( $row->$textField ) ) {
 747                         $text = $row->$textField;
 748                 } else {
 749                         wfProfileOut( __METHOD__ );
 750                         return false;
 751                 }
 752
 753                 # Use external methods for external objects, text in table is URL-only then
 754                 if ( in_array( 'external', $flags ) ) {
 755                         $url = $text;
 756                         @list(/* $proto */, $path ) = explode( '://', $url, 2 );
 757                         if( $path == '' ) {
 758                                 wfProfileOut( __METHOD__ );
 759                                 return false;
 760                         }
 761                         $text = ExternalStore::fetchFromURL( $url );
 762                 }
 763
 764                 // If the text was fetched without an error, convert it
 765                 if ( $text !== false ) {
 766                         if( in_array( 'gzip', $flags ) ) {
 767                                 # Deal with optional compression of archived pages.
 768                                 # This can be done periodically via maintenance/compressOld.php, and
 769                                 # as pages are saved if $wgCompressRevisions is set.
 770                                 $text = gzinflate( $text );
 771                         }
 772
 773                         if( in_array( 'object', $flags ) ) {
 774                                 # Generic compressed storage
 775                                 $obj = unserialize( $text );
 776                                 if ( !is_object( $obj ) ) {
 777                                         // Invalid object
 778                                         wfProfileOut( __METHOD__ );
 779                                         return false;
 780                                 }
 781                                 $text = $obj->getText();
 782                         }
 783
 784                         global $wgLegacyEncoding;
 785                         if( $text !== false && $wgLegacyEncoding
 786                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 787                         {
 788                                 # Old revisions kept around in a legacy encoding?
 789                                 # Upconvert on demand.
 790                                 # ("utf8" checked for compatibility with some broken
 791                                 #  conversion scripts 2008-12-30)
 792                                 global $wgContLang;
 793                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 794                         }
 795                 }
 796                 wfProfileOut( __METHOD__ );
 797                 return $text;
 798         }
 799
 800         /**
 801          * If $wgCompressRevisions is enabled, we will compress data.
 802          * The input string is modified in place.
 803          * Return value is the flags field: contains 'gzip' if the
 804          * data is compressed, and 'utf-8' if we're saving in UTF-8
 805          * mode.
 806          *
 807          * @param $text Mixed: reference to a text
 808          * @return String
 809          */
 810         public static function compressRevisionText( &$text ) {
 811                 global $wgCompressRevisions;
 812                 $flags = array();
 813
 814                 # Revisions not marked this way will be converted
 815                 # on load if $wgLegacyCharset is set in the future.
 816                 $flags[] = 'utf-8';
 817
 818                 if( $wgCompressRevisions ) {
 819                         if( function_exists( 'gzdeflate' ) ) {
 820                                 $text = gzdeflate( $text );
 821                                 $flags[] = 'gzip';
 822                         } else {
 823                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 824                         }
 825                 }
 826                 return implode( ',', $flags );
 827         }
 828
 829         /**
 830          * Insert a new revision into the database, returning the new revision ID
 831          * number on success and dies horribly on failure.
 832          *
 833          * @param $dbw DatabaseBase: (master connection)
 834          * @return Integer
 835          */
 836         public function insertOn( $dbw ) {
 837                 global $wgDefaultExternalStore;
 838
 839                 wfProfileIn( __METHOD__ );
 840
 841                 $data = $this->mText;
 842                 $flags = Revision::compressRevisionText( $data );
 843
 844                 # Write to external storage if required
 845                 if( $wgDefaultExternalStore ) {
 846                         // Store and get the URL
 847                         $data = ExternalStore::insertToDefault( $data );
 848                         if( !$data ) {
 849                                 throw new MWException( "Unable to store text to external storage" );
 850                         }
 851                         if( $flags ) {
 852                                 $flags .= ',';
 853                         }
 854                         $flags .= 'external';
 855                 }
 856
 857                 # Record the text (or external storage URL) to the text table
 858                 if( !isset( $this->mTextId ) ) {
 859                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 860                         $dbw->insert( 'text',
 861                                 array(
 862                                         'old_id'    => $old_id,
 863                                         'old_text'  => $data,
 864                                         'old_flags' => $flags,
 865                                 ), __METHOD__
 866                         );
 867                         $this->mTextId = $dbw->insertId();
 868                 }
 869
 870                 if ( $this->mComment === null ) $this->mComment = "";
 871
 872                 # Record the edit in revisions
 873                 $rev_id = isset( $this->mId )
 874                         ? $this->mId
 875                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 876                 $dbw->insert( 'revision',
 877                         array(
 878                                 'rev_id'         => $rev_id,
 879                                 'rev_page'       => $this->mPage,
 880                                 'rev_text_id'    => $this->mTextId,
 881                                 'rev_comment'    => $this->mComment,
 882                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 883                                 'rev_user'       => $this->mUser,
 884                                 'rev_user_text'  => $this->mUserText,
 885                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 886                                 'rev_deleted'    => $this->mDeleted,
 887                                 'rev_len'        => $this->mSize,
 888                                 'rev_parent_id'  => is_null($this->mParentId) ?
 889                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 890                         ), __METHOD__
 891                 );
 892
 893                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 894
 895                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 896
 897                 wfProfileOut( __METHOD__ );
 898                 return $this->mId;
 899         }
 900
 901         /**
 902          * Lazy-load the revision's text.
 903          * Currently hardcoded to the 'text' table storage engine.
 904          *
 905          * @return String
 906          */
 907         protected function loadText() {
 908                 wfProfileIn( __METHOD__ );
 909
 910                 // Caching may be beneficial for massive use of external storage
 911                 global $wgRevisionCacheExpiry, $wgMemc;
 912                 $textId = $this->getTextId();
 913                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 914                 if( $wgRevisionCacheExpiry ) {
 915                         $text = $wgMemc->get( $key );
 916                         if( is_string( $text ) ) {
 917                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 918                                 wfProfileOut( __METHOD__ );
 919                                 return $text;
 920                         }
 921                 }
 922
 923                 // If we kept data for lazy extraction, use it now...
 924                 if ( isset( $this->mTextRow ) ) {
 925                         $row = $this->mTextRow;
 926                         $this->mTextRow = null;
 927                 } else {
 928                         $row = null;
 929                 }
 930
 931                 if( !$row ) {
 932                         // Text data is immutable; check slaves first.
 933                         $dbr = wfGetDB( DB_SLAVE );
 934                         $row = $dbr->selectRow( 'text',
 935                                 array( 'old_text', 'old_flags' ),
 936                                 array( 'old_id' => $this->getTextId() ),
 937                                 __METHOD__ );
 938                 }
 939
 940                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 941                         // Possible slave lag!
 942                         $dbw = wfGetDB( DB_MASTER );
 943                         $row = $dbw->selectRow( 'text',
 944                                 array( 'old_text', 'old_flags' ),
 945                                 array( 'old_id' => $this->getTextId() ),
 946                                 __METHOD__ );
 947                 }
 948
 949                 $text = self::getRevisionText( $row );
 950
 951                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 952                 if( $wgRevisionCacheExpiry && $text !== false ) {
 953                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 954                 }
 955
 956                 wfProfileOut( __METHOD__ );
 957
 958                 return $text;
 959         }
 960
 961         /**
 962          * Create a new null-revision for insertion into a page's
 963          * history. This will not re-save the text, but simply refer
 964          * to the text from the previous version.
 965          *
 966          * Such revisions can for instance identify page rename
 967          * operations and other such meta-modifications.
 968          *
 969          * @param $dbw DatabaseBase
 970          * @param $pageId Integer: ID number of the page to read from
 971          * @param $summary String: revision's summary
 972          * @param $minor Boolean: whether the revision should be considered as minor
 973          * @return Revision|null on error
 974          */
 975         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 976                 wfProfileIn( __METHOD__ );
 977
 978                 $current = $dbw->selectRow(
 979                         array( 'page', 'revision' ),
 980                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 981                         array(
 982                                 'page_id' => $pageId,
 983                                 'page_latest=rev_id',
 984                                 ),
 985                         __METHOD__ );
 986
 987                 if( $current ) {
 988                         $revision = new Revision( array(
 989                                 'page'       => $pageId,
 990                                 'comment'    => $summary,
 991                                 'minor_edit' => $minor,
 992                                 'text_id'    => $current->rev_text_id,
 993                                 'parent_id'  => $current->page_latest,
 994                                 'len'        => $current->rev_len
 995                                 ) );
 996                 } else {
 997                         $revision = null;
 998                 }
 999
1000                 wfProfileOut( __METHOD__ );
1001                 return $revision;
1002         }
1003
1004         /**
1005          * Determine if the current user is allowed to view a particular
1006          * field of this revision, if it's marked as deleted.
1007          *
1008          * @param $field Integer:one of self::DELETED_TEXT,
1009          *                              self::DELETED_COMMENT,
1010          *                              self::DELETED_USER
1011          * @return Boolean
1012          */
1013         public function userCan( $field ) {
1014                 return self::userCanBitfield( $this->mDeleted, $field );
1015         }
1016
1017         /**
1018          * Determine if the current user is allowed to view a particular
1019          * field of this revision, if it's marked as deleted. This is used
1020          * by various classes to avoid duplication.
1021          *
1022          * @param $bitfield Integer: current field
1023          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1024          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1025          *                               self::DELETED_USER = File::DELETED_USER
1026          * @return Boolean
1027          */
1028         public static function userCanBitfield( $bitfield, $field ) {
1029                 if( $bitfield & $field ) { // aspect is deleted
1030                         global $wgUser;
1031                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1032                                 $permission = 'suppressrevision';
1033                         } elseif ( $field & self::DELETED_TEXT ) {
1034                                 $permission = 'deletedtext';
1035                         } else {
1036                                 $permission = 'deletedhistory';
1037                         }
1038                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1039                         return $wgUser->isAllowed( $permission );
1040                 } else {
1041                         return true;
1042                 }
1043         }
1044
1045         /**
1046          * Get rev_timestamp from rev_id, without loading the rest of the row
1047          *
1048          * @param $title Title
1049          * @param $id Integer
1050          * @return String
1051          */
1052         static function getTimestampFromId( $title, $id ) {
1053                 $dbr = wfGetDB( DB_SLAVE );
1054                 // Casting fix for DB2
1055                 if ( $id == '' ) {
1056                         $id = 0;
1057                 }
1058                 $conds = array( 'rev_id' => $id );
1059                 $conds['rev_page'] = $title->getArticleId();
1060                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1061                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1062                         # Not in slave, try master
1063                         $dbw = wfGetDB( DB_MASTER );
1064                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1065                 }
1066                 return wfTimestamp( TS_MW, $timestamp );
1067         }
1068
1069         /**
1070          * Get count of revisions per page...not very efficient
1071          *
1072          * @param $db DatabaseBase
1073          * @param $id Integer: page id
1074          * @return Integer
1075          */
1076         static function countByPageId( $db, $id ) {
1077                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1078                         array( 'rev_page' => $id ), __METHOD__ );
1079                 if( $row ) {
1080                         return $row->revCount;
1081                 }
1082                 return 0;
1083         }
1084
1085         /**
1086          * Get count of revisions per page...not very efficient
1087          *
1088          * @param $db DatabaseBase
1089          * @param $title Title
1090          * @return Integer
1091          */
1092         static function countByTitle( $db, $title ) {
1093                 $id = $title->getArticleId();
1094                 if( $id ) {
1095                         return Revision::countByPageId( $db, $id );
1096                 }
1097                 return 0;
1098         }
1099 }
1100
1101 /**
1102  * Aliases for backwards compatibility with 1.6
1103  */
1104 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
1105 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
1106 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
1107 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );