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'] = $revId;
  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                 $conds[] = 'page_id=rev_page';
  89                 return Revision::newFromConds( $conds );
  90         }
  91
  92         /**
  93          * Make a fake revision object from an archive table row. This is queried
  94          * for permissions or even inserted (as in Special:Undelete)
  95          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
  96          *
  97          * @param $row
  98          * @param $overrides array
  99          *
 100          * @return Revision
 101          */
 102         public static function newFromArchiveRow( $row, $overrides = array() ) {
 103                 $attribs = $overrides + array(
 104                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 105                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 106                         'comment'    => $row->ar_comment,
 107                         'user'       => $row->ar_user,
 108                         'user_text'  => $row->ar_user_text,
 109                         'timestamp'  => $row->ar_timestamp,
 110                         'minor_edit' => $row->ar_minor_edit,
 111                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 112                         'deleted'    => $row->ar_deleted,
 113                         'len'        => $row->ar_len
 114                 );
 115                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 116                         // Pre-1.5 ar_text row
 117                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 118                         if ( $attribs['text'] === false ) {
 119                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 120                         }
 121                 }
 122                 return new self( $attribs );
 123         }
 124
 125         /**
 126          * @since 1.19
 127          *
 128          * @param $row
 129          * @return Revision
 130          */
 131         public static function newFromRow( $row ) {
 132                 return new self( $row );
 133         }
 134
 135         /**
 136          * Load a page revision from a given revision ID number.
 137          * Returns null if no such revision can be found.
 138          *
 139          * @param $db DatabaseBase
 140          * @param $id Integer
 141          * @return Revision or null
 142          */
 143         public static function loadFromId( $db, $id ) {
 144                 return Revision::loadFromConds( $db,
 145                         array( 'page_id=rev_page',
 146                                    'rev_id' => intval( $id ) ) );
 147         }
 148
 149         /**
 150          * Load either the current, or a specified, revision
 151          * that's attached to a given page. If not attached
 152          * to that page, will return null.
 153          *
 154          * @param $db DatabaseBase
 155          * @param $pageid Integer
 156          * @param $id Integer
 157          * @return Revision or null
 158          */
 159         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 160                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 161                 if( $id ) {
 162                         $conds['rev_id'] = intval( $id );
 163                 } else {
 164                         $conds[] = 'rev_id=page_latest';
 165                 }
 166                 return Revision::loadFromConds( $db, $conds );
 167         }
 168
 169         /**
 170          * Load either the current, or a specified, revision
 171          * that's attached to a given page. If not attached
 172          * to that page, will return null.
 173          *
 174          * @param $db DatabaseBase
 175          * @param $title Title
 176          * @param $id Integer
 177          * @return Revision or null
 178          */
 179         public static function loadFromTitle( $db, $title, $id = 0 ) {
 180                 if( $id ) {
 181                         $matchId = intval( $id );
 182                 } else {
 183                         $matchId = 'page_latest';
 184                 }
 185                 return Revision::loadFromConds(
 186                         $db,
 187                         array( "rev_id=$matchId",
 188                                    'page_id=rev_page',
 189                                    'page_namespace' => $title->getNamespace(),
 190                                    'page_title'     => $title->getDBkey() ) );
 191         }
 192
 193         /**
 194          * Load the revision for the given title with the given timestamp.
 195          * WARNING: Timestamps may in some circumstances not be unique,
 196          * so this isn't the best key to use.
 197          *
 198          * @param $db DatabaseBase
 199          * @param $title Title
 200          * @param $timestamp String
 201          * @return Revision or null
 202          */
 203         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 204                 return Revision::loadFromConds(
 205                         $db,
 206                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 207                                    'page_id=rev_page',
 208                                    'page_namespace' => $title->getNamespace(),
 209                                    'page_title'     => $title->getDBkey() ) );
 210         }
 211
 212         /**
 213          * Given a set of conditions, fetch a revision.
 214          *
 215          * @param $conditions Array
 216          * @return Revision or null
 217          */
 218         public static function newFromConds( $conditions ) {
 219                 $db = wfGetDB( DB_SLAVE );
 220                 $row = Revision::loadFromConds( $db, $conditions );
 221                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 222                         $dbw = wfGetDB( DB_MASTER );
 223                         $row = Revision::loadFromConds( $dbw, $conditions );
 224                 }
 225                 return $row;
 226         }
 227
 228         /**
 229          * Given a set of conditions, fetch a revision from
 230          * the given database connection.
 231          *
 232          * @param $db DatabaseBase
 233          * @param $conditions Array
 234          * @return Revision or null
 235          */
 236         private static function loadFromConds( $db, $conditions ) {
 237                 $res = Revision::fetchFromConds( $db, $conditions );
 238                 if( $res ) {
 239                         $row = $res->fetchObject();
 240                         $res->free();
 241                         if( $row ) {
 242                                 $ret = new Revision( $row );
 243                                 return $ret;
 244                         }
 245                 }
 246                 $ret = null;
 247                 return $ret;
 248         }
 249
 250         /**
 251          * Return a wrapper for a series of database rows to
 252          * fetch all of a given page's revisions in turn.
 253          * Each row can be fed to the constructor to get objects.
 254          *
 255          * @param $title Title
 256          * @return ResultWrapper
 257          */
 258         public static function fetchRevision( $title ) {
 259                 return Revision::fetchFromConds(
 260                         wfGetDB( DB_SLAVE ),
 261                         array( 'rev_id=page_latest',
 262                                    'page_namespace' => $title->getNamespace(),
 263                                    'page_title'     => $title->getDBkey(),
 264                                    'page_id=rev_page' ) );
 265         }
 266
 267         /**
 268          * Given a set of conditions, return a ResultWrapper
 269          * which will return matching database rows with the
 270          * fields necessary to build Revision objects.
 271          *
 272          * @param $db DatabaseBase
 273          * @param $conditions Array
 274          * @return ResultWrapper
 275          */
 276         private static function fetchFromConds( $db, $conditions ) {
 277                 $fields = self::selectFields();
 278                 $fields[] = 'page_namespace';
 279                 $fields[] = 'page_title';
 280                 $fields[] = 'page_latest';
 281                 return $db->select(
 282                         array( 'page', 'revision' ),
 283                         $fields,
 284                         $conditions,
 285                         __METHOD__,
 286                         array( 'LIMIT' => 1 ) );
 287         }
 288
 289         /**
 290          * Return the list of revision fields that should be selected to create
 291          * a new revision.
 292          */
 293         public static function selectFields() {
 294                 return array(
 295                         'rev_id',
 296                         'rev_page',
 297                         'rev_text_id',
 298                         'rev_timestamp',
 299                         'rev_comment',
 300                         'rev_user_text,'.
 301                         'rev_user',
 302                         'rev_minor_edit',
 303                         'rev_deleted',
 304                         'rev_len',
 305                         'rev_parent_id'
 306                 );
 307         }
 308
 309         /**
 310          * Return the list of text fields that should be selected to read the
 311          * revision text
 312          */
 313         static function selectTextFields() {
 314                 return array(
 315                         'old_text',
 316                         'old_flags'
 317                 );
 318         }
 319
 320         /**
 321          * Return the list of page fields that should be selected from page table
 322          */
 323         static function selectPageFields() {
 324                 return array(
 325                         'page_namespace',
 326                         'page_title',
 327                         'page_latest'
 328                 );
 329         }
 330
 331         /**
 332          * Constructor
 333          *
 334          * @param $row Mixed: either a database row or an array
 335          * @access private
 336          */
 337         function __construct( $row ) {
 338                 if( is_object( $row ) ) {
 339                         $this->mId        = intval( $row->rev_id );
 340                         $this->mPage      = intval( $row->rev_page );
 341                         $this->mTextId    = intval( $row->rev_text_id );
 342                         $this->mComment   =         $row->rev_comment;
 343                         $this->mUserText  =         $row->rev_user_text;
 344                         $this->mUser      = intval( $row->rev_user );
 345                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 346                         $this->mTimestamp =         $row->rev_timestamp;
 347                         $this->mDeleted   = intval( $row->rev_deleted );
 348
 349                         if( !isset( $row->rev_parent_id ) ) {
 350                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 351                         } else {
 352                                 $this->mParentId  = intval( $row->rev_parent_id );
 353                         }
 354
 355                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 356                                 $this->mSize = null;
 357                         } else {
 358                                 $this->mSize = intval( $row->rev_len );
 359                         }
 360
 361                         if( isset( $row->page_latest ) ) {
 362                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 363                                 $this->mTitle = Title::newFromRow( $row );
 364                         } else {
 365                                 $this->mCurrent = false;
 366                                 $this->mTitle = null;
 367                         }
 368
 369                         // Lazy extraction...
 370                         $this->mText      = null;
 371                         if( isset( $row->old_text ) ) {
 372                                 $this->mTextRow = $row;
 373                         } else {
 374                                 // 'text' table row entry will be lazy-loaded
 375                                 $this->mTextRow = null;
 376                         }
 377                 } elseif( is_array( $row ) ) {
 378                         // Build a new revision to be saved...
 379                         global $wgUser;
 380
 381                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 382                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 383                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 384                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 385                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 386                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 387                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 388                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 389                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 390                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 391
 392                         // Enforce spacing trimming on supplied text
 393                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 394                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 395                         $this->mTextRow   = null;
 396
 397                         $this->mTitle     = null; # Load on demand if needed
 398                         $this->mCurrent   = false;
 399                         # If we still have no len_size, see it we have the text to figure it out
 400                         if ( !$this->mSize )
 401                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 402                 } else {
 403                         throw new MWException( 'Revision constructor passed invalid row format.' );
 404                 }
 405                 $this->mUnpatrolled = null;
 406         }
 407
 408         /**
 409          * Get revision ID
 410          *
 411          * @return Integer
 412          */
 413         public function getId() {
 414                 return $this->mId;
 415         }
 416
 417         /**
 418          * Get text row ID
 419          *
 420          * @return Integer
 421          */
 422         public function getTextId() {
 423                 return $this->mTextId;
 424         }
 425
 426         /**
 427          * Get parent revision ID (the original previous page revision)
 428          *
 429          * @return Integer
 430          */
 431         public function getParentId() {
 432                 return $this->mParentId;
 433         }
 434
 435         /**
 436          * Returns the length of the text in this revision, or null if unknown.
 437          *
 438          * @return Integer
 439          */
 440         public function getSize() {
 441                 return $this->mSize;
 442         }
 443
 444         /**
 445          * Returns the title of the page associated with this entry.
 446          *
 447          * @return Title
 448          */
 449         public function getTitle() {
 450                 if( isset( $this->mTitle ) ) {
 451                         return $this->mTitle;
 452                 }
 453                 $dbr = wfGetDB( DB_SLAVE );
 454                 $row = $dbr->selectRow(
 455                         array( 'page', 'revision' ),
 456                         array( 'page_namespace', 'page_title' ),
 457                         array( 'page_id=rev_page',
 458                                    'rev_id' => $this->mId ),
 459                         'Revision::getTitle' );
 460                 if( $row ) {
 461                         $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 462                 }
 463                 return $this->mTitle;
 464         }
 465
 466         /**
 467          * Set the title of the revision
 468          *
 469          * @param $title Title
 470          */
 471         public function setTitle( $title ) {
 472                 $this->mTitle = $title;
 473         }
 474
 475         /**
 476          * Get the page ID
 477          *
 478          * @return Integer
 479          */
 480         public function getPage() {
 481                 return $this->mPage;
 482         }
 483
 484         /**
 485          * Fetch revision's user id if it's available to the specified audience.
 486          * If the specified audience does not have access to it, zero will be
 487          * returned.
 488          *
 489          * @param $audience Integer: one of:
 490          *      Revision::FOR_PUBLIC       to be displayed to all users
 491          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 492          *      Revision::RAW              get the ID regardless of permissions
 493          * @param $user User object to check for, only if FOR_THIS_USER is passed
 494          *              to the $audience parameter
 495          * @return Integer
 496          */
 497         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 498                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 499                         return 0;
 500                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 501                         return 0;
 502                 } else {
 503                         return $this->mUser;
 504                 }
 505         }
 506
 507         /**
 508          * Fetch revision's user id without regard for the current user's permissions
 509          *
 510          * @return String
 511          */
 512         public function getRawUser() {
 513                 return $this->mUser;
 514         }
 515
 516         /**
 517          * Fetch revision's username if it's available to the specified audience.
 518          * If the specified audience does not have access to the username, an
 519          * empty string will be returned.
 520          *
 521          * @param $audience Integer: one of:
 522          *      Revision::FOR_PUBLIC       to be displayed to all users
 523          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 524          *      Revision::RAW              get the text regardless of permissions
 525          * @param $user User object to check for, only if FOR_THIS_USER is passed
 526          *              to the $audience parameter
 527          * @return string
 528          */
 529         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 530                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 531                         return '';
 532                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 533                         return '';
 534                 } else {
 535                         return $this->mUserText;
 536                 }
 537         }
 538
 539         /**
 540          * Fetch revision's username without regard for view restrictions
 541          *
 542          * @return String
 543          */
 544         public function getRawUserText() {
 545                 return $this->mUserText;
 546         }
 547
 548         /**
 549          * Fetch revision comment if it's available to the specified audience.
 550          * If the specified audience does not have access to the comment, an
 551          * empty string will be returned.
 552          *
 553          * @param $audience Integer: one of:
 554          *      Revision::FOR_PUBLIC       to be displayed to all users
 555          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 556          *      Revision::RAW              get the text regardless of permissions
 557          * @param $user User object to check for, only if FOR_THIS_USER is passed
 558          *              to the $audience parameter
 559          * @return String
 560          */
 561         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 562                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 563                         return '';
 564                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 565                         return '';
 566                 } else {
 567                         return $this->mComment;
 568                 }
 569         }
 570
 571         /**
 572          * Fetch revision comment without regard for the current user's permissions
 573          *
 574          * @return String
 575          */
 576         public function getRawComment() {
 577                 return $this->mComment;
 578         }
 579
 580         /**
 581          * @return Boolean
 582          */
 583         public function isMinor() {
 584                 return (bool)$this->mMinorEdit;
 585         }
 586
 587         /**
 588          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 589          */
 590         public function isUnpatrolled() {
 591                 if( $this->mUnpatrolled !== null ) {
 592                         return $this->mUnpatrolled;
 593                 }
 594                 $dbr = wfGetDB( DB_SLAVE );
 595                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 596                         'rc_id',
 597                         array( // Add redundant user,timestamp condition so we can use the existing index
 598                                 'rc_user_text'  => $this->getRawUserText(),
 599                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 600                                 'rc_this_oldid' => $this->getId(),
 601                                 'rc_patrolled'  => 0
 602                         ),
 603                         __METHOD__
 604                 );
 605                 return (int)$this->mUnpatrolled;
 606         }
 607
 608         /**
 609          * @param $field int one of DELETED_* bitfield constants
 610          *
 611          * @return Boolean
 612          */
 613         public function isDeleted( $field ) {
 614                 return ( $this->mDeleted & $field ) == $field;
 615         }
 616
 617         /**
 618          * Get the deletion bitfield of the revision
 619          *
 620          * @return int
 621          */
 622         public function getVisibility() {
 623                 return (int)$this->mDeleted;
 624         }
 625
 626         /**
 627          * Fetch revision text if it's available to the specified audience.
 628          * If the specified audience does not have the ability to view this
 629          * revision, an empty string will be returned.
 630          *
 631          * @param $audience Integer: one of:
 632          *      Revision::FOR_PUBLIC       to be displayed to all users
 633          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 634          *      Revision::RAW              get the text regardless of permissions
 635          * @param $user User object to check for, only if FOR_THIS_USER is passed
 636          *              to the $audience parameter
 637          * @return String
 638          */
 639         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 640                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 641                         return '';
 642                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 643                         return '';
 644                 } else {
 645                         return $this->getRawText();
 646                 }
 647         }
 648
 649         /**
 650          * Alias for getText(Revision::FOR_THIS_USER)
 651          *
 652          * @deprecated since 1.17
 653          * @return String
 654          */
 655         public function revText() {
 656                 wfDeprecated( __METHOD__ );
 657                 return $this->getText( self::FOR_THIS_USER );
 658         }
 659
 660         /**
 661          * Fetch revision text without regard for view restrictions
 662          *
 663          * @return String
 664          */
 665         public function getRawText() {
 666                 if( is_null( $this->mText ) ) {
 667                         // Revision text is immutable. Load on demand:
 668                         $this->mText = $this->loadText();
 669                 }
 670                 return $this->mText;
 671         }
 672
 673         /**
 674          * @return String
 675          */
 676         public function getTimestamp() {
 677                 return wfTimestamp( TS_MW, $this->mTimestamp );
 678         }
 679
 680         /**
 681          * @return Boolean
 682          */
 683         public function isCurrent() {
 684                 return $this->mCurrent;
 685         }
 686
 687         /**
 688          * Get previous revision for this title
 689          *
 690          * @return Revision or null
 691          */
 692         public function getPrevious() {
 693                 if( $this->getTitle() ) {
 694                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 695                         if( $prev ) {
 696                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 697                         }
 698                 }
 699                 return null;
 700         }
 701
 702         /**
 703          * Get next revision for this title
 704          *
 705          * @return Revision or null
 706          */
 707         public function getNext() {
 708                 if( $this->getTitle() ) {
 709                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 710                         if ( $next ) {
 711                                 return Revision::newFromTitle( $this->getTitle(), $next );
 712                         }
 713                 }
 714                 return null;
 715         }
 716
 717         /**
 718          * Get previous revision Id for this page_id
 719          * This is used to populate rev_parent_id on save
 720          *
 721          * @param $db DatabaseBase
 722          * @return Integer
 723          */
 724         private function getPreviousRevisionId( $db ) {
 725                 if( is_null( $this->mPage ) ) {
 726                         return 0;
 727                 }
 728                 # Use page_latest if ID is not given
 729                 if( !$this->mId ) {
 730                         $prevId = $db->selectField( 'page', 'page_latest',
 731                                 array( 'page_id' => $this->mPage ),
 732                                 __METHOD__ );
 733                 } else {
 734                         $prevId = $db->selectField( 'revision', 'rev_id',
 735                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 736                                 __METHOD__,
 737                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 738                 }
 739                 return intval( $prevId );
 740         }
 741
 742         /**
 743           * Get revision text associated with an old or archive row
 744           * $row is usually an object from wfFetchRow(), both the flags and the text
 745           * field must be included
 746           *
 747           * @param $row Object: the text data
 748           * @param $prefix String: table prefix (default 'old_')
 749           * @return String: text the text requested or false on failure
 750           */
 751         public static function getRevisionText( $row, $prefix = 'old_' ) {
 752                 wfProfileIn( __METHOD__ );
 753
 754                 # Get data
 755                 $textField = $prefix . 'text';
 756                 $flagsField = $prefix . 'flags';
 757
 758                 if( isset( $row->$flagsField ) ) {
 759                         $flags = explode( ',', $row->$flagsField );
 760                 } else {
 761                         $flags = array();
 762                 }
 763
 764                 if( isset( $row->$textField ) ) {
 765                         $text = $row->$textField;
 766                 } else {
 767                         wfProfileOut( __METHOD__ );
 768                         return false;
 769                 }
 770
 771                 # Use external methods for external objects, text in table is URL-only then
 772                 if ( in_array( 'external', $flags ) ) {
 773                         $url = $text;
 774                         $parts = explode( '://', $url, 2 );
 775                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 776                                 wfProfileOut( __METHOD__ );
 777                                 return false;
 778                         }
 779                         $text = ExternalStore::fetchFromURL( $url );
 780                 }
 781
 782                 // If the text was fetched without an error, convert it
 783                 if ( $text !== false ) {
 784                         if( in_array( 'gzip', $flags ) ) {
 785                                 # Deal with optional compression of archived pages.
 786                                 # This can be done periodically via maintenance/compressOld.php, and
 787                                 # as pages are saved if $wgCompressRevisions is set.
 788                                 $text = gzinflate( $text );
 789                         }
 790
 791                         if( in_array( 'object', $flags ) ) {
 792                                 # Generic compressed storage
 793                                 $obj = unserialize( $text );
 794                                 if ( !is_object( $obj ) ) {
 795                                         // Invalid object
 796                                         wfProfileOut( __METHOD__ );
 797                                         return false;
 798                                 }
 799                                 $text = $obj->getText();
 800                         }
 801
 802                         global $wgLegacyEncoding;
 803                         if( $text !== false && $wgLegacyEncoding
 804                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 805                         {
 806                                 # Old revisions kept around in a legacy encoding?
 807                                 # Upconvert on demand.
 808                                 # ("utf8" checked for compatibility with some broken
 809                                 #  conversion scripts 2008-12-30)
 810                                 global $wgContLang;
 811                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 812                         }
 813                 }
 814                 wfProfileOut( __METHOD__ );
 815                 return $text;
 816         }
 817
 818         /**
 819          * If $wgCompressRevisions is enabled, we will compress data.
 820          * The input string is modified in place.
 821          * Return value is the flags field: contains 'gzip' if the
 822          * data is compressed, and 'utf-8' if we're saving in UTF-8
 823          * mode.
 824          *
 825          * @param $text Mixed: reference to a text
 826          * @return String
 827          */
 828         public static function compressRevisionText( &$text ) {
 829                 global $wgCompressRevisions;
 830                 $flags = array();
 831
 832                 # Revisions not marked this way will be converted
 833                 # on load if $wgLegacyCharset is set in the future.
 834                 $flags[] = 'utf-8';
 835
 836                 if( $wgCompressRevisions ) {
 837                         if( function_exists( 'gzdeflate' ) ) {
 838                                 $text = gzdeflate( $text );
 839                                 $flags[] = 'gzip';
 840                         } else {
 841                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 842                         }
 843                 }
 844                 return implode( ',', $flags );
 845         }
 846
 847         /**
 848          * Insert a new revision into the database, returning the new revision ID
 849          * number on success and dies horribly on failure.
 850          *
 851          * @param $dbw DatabaseBase: (master connection)
 852          * @return Integer
 853          */
 854         public function insertOn( $dbw ) {
 855                 global $wgDefaultExternalStore;
 856
 857                 wfProfileIn( __METHOD__ );
 858
 859                 $data = $this->mText;
 860                 $flags = Revision::compressRevisionText( $data );
 861
 862                 # Write to external storage if required
 863                 if( $wgDefaultExternalStore ) {
 864                         // Store and get the URL
 865                         $data = ExternalStore::insertToDefault( $data );
 866                         if( !$data ) {
 867                                 throw new MWException( "Unable to store text to external storage" );
 868                         }
 869                         if( $flags ) {
 870                                 $flags .= ',';
 871                         }
 872                         $flags .= 'external';
 873                 }
 874
 875                 # Record the text (or external storage URL) to the text table
 876                 if( !isset( $this->mTextId ) ) {
 877                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 878                         $dbw->insert( 'text',
 879                                 array(
 880                                         'old_id'    => $old_id,
 881                                         'old_text'  => $data,
 882                                         'old_flags' => $flags,
 883                                 ), __METHOD__
 884                         );
 885                         $this->mTextId = $dbw->insertId();
 886                 }
 887
 888                 if ( $this->mComment === null ) $this->mComment = "";
 889
 890                 # Record the edit in revisions
 891                 $rev_id = isset( $this->mId )
 892                         ? $this->mId
 893                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 894                 $dbw->insert( 'revision',
 895                         array(
 896                                 'rev_id'         => $rev_id,
 897                                 'rev_page'       => $this->mPage,
 898                                 'rev_text_id'    => $this->mTextId,
 899                                 'rev_comment'    => $this->mComment,
 900                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 901                                 'rev_user'       => $this->mUser,
 902                                 'rev_user_text'  => $this->mUserText,
 903                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 904                                 'rev_deleted'    => $this->mDeleted,
 905                                 'rev_len'        => $this->mSize,
 906                                 'rev_parent_id'  => is_null($this->mParentId) ?
 907                                         $this->getPreviousRevisionId( $dbw ) : $this->mParentId
 908                         ), __METHOD__
 909                 );
 910
 911                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 912
 913                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 914
 915                 wfProfileOut( __METHOD__ );
 916                 return $this->mId;
 917         }
 918
 919         /**
 920          * Lazy-load the revision's text.
 921          * Currently hardcoded to the 'text' table storage engine.
 922          *
 923          * @return String
 924          */
 925         protected function loadText() {
 926                 wfProfileIn( __METHOD__ );
 927
 928                 // Caching may be beneficial for massive use of external storage
 929                 global $wgRevisionCacheExpiry, $wgMemc;
 930                 $textId = $this->getTextId();
 931                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 932                 if( $wgRevisionCacheExpiry ) {
 933                         $text = $wgMemc->get( $key );
 934                         if( is_string( $text ) ) {
 935                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 936                                 wfProfileOut( __METHOD__ );
 937                                 return $text;
 938                         }
 939                 }
 940
 941                 // If we kept data for lazy extraction, use it now...
 942                 if ( isset( $this->mTextRow ) ) {
 943                         $row = $this->mTextRow;
 944                         $this->mTextRow = null;
 945                 } else {
 946                         $row = null;
 947                 }
 948
 949                 if( !$row ) {
 950                         // Text data is immutable; check slaves first.
 951                         $dbr = wfGetDB( DB_SLAVE );
 952                         $row = $dbr->selectRow( 'text',
 953                                 array( 'old_text', 'old_flags' ),
 954                                 array( 'old_id' => $this->getTextId() ),
 955                                 __METHOD__ );
 956                 }
 957
 958                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 959                         // Possible slave lag!
 960                         $dbw = wfGetDB( DB_MASTER );
 961                         $row = $dbw->selectRow( 'text',
 962                                 array( 'old_text', 'old_flags' ),
 963                                 array( 'old_id' => $this->getTextId() ),
 964                                 __METHOD__ );
 965                 }
 966
 967                 $text = self::getRevisionText( $row );
 968
 969                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 970                 if( $wgRevisionCacheExpiry && $text !== false ) {
 971                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 972                 }
 973
 974                 wfProfileOut( __METHOD__ );
 975
 976                 return $text;
 977         }
 978
 979         /**
 980          * Create a new null-revision for insertion into a page's
 981          * history. This will not re-save the text, but simply refer
 982          * to the text from the previous version.
 983          *
 984          * Such revisions can for instance identify page rename
 985          * operations and other such meta-modifications.
 986          *
 987          * @param $dbw DatabaseBase
 988          * @param $pageId Integer: ID number of the page to read from
 989          * @param $summary String: revision's summary
 990          * @param $minor Boolean: whether the revision should be considered as minor
 991          * @return Revision|null on error
 992          */
 993         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
 994                 wfProfileIn( __METHOD__ );
 995
 996                 $current = $dbw->selectRow(
 997                         array( 'page', 'revision' ),
 998                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
 999                         array(
1000                                 'page_id' => $pageId,
1001                                 'page_latest=rev_id',
1002                                 ),
1003                         __METHOD__ );
1004
1005                 if( $current ) {
1006                         $revision = new Revision( array(
1007                                 'page'       => $pageId,
1008                                 'comment'    => $summary,
1009                                 'minor_edit' => $minor,
1010                                 'text_id'    => $current->rev_text_id,
1011                                 'parent_id'  => $current->page_latest,
1012                                 'len'        => $current->rev_len
1013                                 ) );
1014                 } else {
1015                         $revision = null;
1016                 }
1017
1018                 wfProfileOut( __METHOD__ );
1019                 return $revision;
1020         }
1021
1022         /**
1023          * Determine if the current user is allowed to view a particular
1024          * field of this revision, if it's marked as deleted.
1025          *
1026          * @param $field Integer:one of self::DELETED_TEXT,
1027          *                              self::DELETED_COMMENT,
1028          *                              self::DELETED_USER
1029          * @param $user User object to check, or null to use $wgUser
1030          * @return Boolean
1031          */
1032         public function userCan( $field, User $user = null ) {
1033                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1034         }
1035
1036         /**
1037          * Determine if the current user is allowed to view a particular
1038          * field of this revision, if it's marked as deleted. This is used
1039          * by various classes to avoid duplication.
1040          *
1041          * @param $bitfield Integer: current field
1042          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1043          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1044          *                               self::DELETED_USER = File::DELETED_USER
1045          * @param $user User object to check, or null to use $wgUser
1046          * @return Boolean
1047          */
1048         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1049                 if( $bitfield & $field ) { // aspect is deleted
1050                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1051                                 $permission = 'suppressrevision';
1052                         } elseif ( $field & self::DELETED_TEXT ) {
1053                                 $permission = 'deletedtext';
1054                         } else {
1055                                 $permission = 'deletedhistory';
1056                         }
1057                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1058                         if ( $user === null ) {
1059                                 global $wgUser;
1060                                 $user = $wgUser;
1061                         }
1062                         return $user->isAllowed( $permission );
1063                 } else {
1064                         return true;
1065                 }
1066         }
1067
1068         /**
1069          * Get rev_timestamp from rev_id, without loading the rest of the row
1070          *
1071          * @param $title Title
1072          * @param $id Integer
1073          * @return String
1074          */
1075         static function getTimestampFromId( $title, $id ) {
1076                 $dbr = wfGetDB( DB_SLAVE );
1077                 // Casting fix for DB2
1078                 if ( $id == '' ) {
1079                         $id = 0;
1080                 }
1081                 $conds = array( 'rev_id' => $id );
1082                 $conds['rev_page'] = $title->getArticleId();
1083                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1084                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1085                         # Not in slave, try master
1086                         $dbw = wfGetDB( DB_MASTER );
1087                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1088                 }
1089                 return wfTimestamp( TS_MW, $timestamp );
1090         }
1091
1092         /**
1093          * Get count of revisions per page...not very efficient
1094          *
1095          * @param $db DatabaseBase
1096          * @param $id Integer: page id
1097          * @return Integer
1098          */
1099         static function countByPageId( $db, $id ) {
1100                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1101                         array( 'rev_page' => $id ), __METHOD__ );
1102                 if( $row ) {
1103                         return $row->revCount;
1104                 }
1105                 return 0;
1106         }
1107
1108         /**
1109          * Get count of revisions per page...not very efficient
1110          *
1111          * @param $db DatabaseBase
1112          * @param $title Title
1113          * @return Integer
1114          */
1115         static function countByTitle( $db, $title ) {
1116                 $id = $title->getArticleId();
1117                 if( $id ) {
1118                         return Revision::countByPageId( $db, $id );
1119                 }
1120                 return 0;
1121         }
1122 }