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                         'sha1'       => $row->ar_sha1
 115                 );
 116                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 117                         // Pre-1.5 ar_text row
 118                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 119                         if ( $attribs['text'] === false ) {
 120                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 121                         }
 122                 }
 123                 return new self( $attribs );
 124         }
 125
 126         /**
 127          * @since 1.19
 128          *
 129          * @param $row
 130          * @return Revision
 131          */
 132         public static function newFromRow( $row ) {
 133                 return new self( $row );
 134         }
 135
 136         /**
 137          * Load a page revision from a given revision ID number.
 138          * Returns null if no such revision can be found.
 139          *
 140          * @param $db DatabaseBase
 141          * @param $id Integer
 142          * @return Revision or null
 143          */
 144         public static function loadFromId( $db, $id ) {
 145                 return Revision::loadFromConds( $db,
 146                         array( 'page_id=rev_page',
 147                                    'rev_id' => intval( $id ) ) );
 148         }
 149
 150         /**
 151          * Load either the current, or a specified, revision
 152          * that's attached to a given page. If not attached
 153          * to that page, will return null.
 154          *
 155          * @param $db DatabaseBase
 156          * @param $pageid Integer
 157          * @param $id Integer
 158          * @return Revision or null
 159          */
 160         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 161                 $conds = array( 'page_id=rev_page','rev_page' => intval( $pageid ), 'page_id'=>intval( $pageid ) );
 162                 if( $id ) {
 163                         $conds['rev_id'] = intval( $id );
 164                 } else {
 165                         $conds[] = 'rev_id=page_latest';
 166                 }
 167                 return Revision::loadFromConds( $db, $conds );
 168         }
 169
 170         /**
 171          * Load either the current, or a specified, revision
 172          * that's attached to a given page. If not attached
 173          * to that page, will return null.
 174          *
 175          * @param $db DatabaseBase
 176          * @param $title Title
 177          * @param $id Integer
 178          * @return Revision or null
 179          */
 180         public static function loadFromTitle( $db, $title, $id = 0 ) {
 181                 if( $id ) {
 182                         $matchId = intval( $id );
 183                 } else {
 184                         $matchId = 'page_latest';
 185                 }
 186                 return Revision::loadFromConds(
 187                         $db,
 188                         array( "rev_id=$matchId",
 189                                    'page_id=rev_page',
 190                                    'page_namespace' => $title->getNamespace(),
 191                                    'page_title'     => $title->getDBkey() ) );
 192         }
 193
 194         /**
 195          * Load the revision for the given title with the given timestamp.
 196          * WARNING: Timestamps may in some circumstances not be unique,
 197          * so this isn't the best key to use.
 198          *
 199          * @param $db DatabaseBase
 200          * @param $title Title
 201          * @param $timestamp String
 202          * @return Revision or null
 203          */
 204         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 205                 return Revision::loadFromConds(
 206                         $db,
 207                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 208                                    'page_id=rev_page',
 209                                    'page_namespace' => $title->getNamespace(),
 210                                    'page_title'     => $title->getDBkey() ) );
 211         }
 212
 213         /**
 214          * Given a set of conditions, fetch a revision.
 215          *
 216          * @param $conditions Array
 217          * @return Revision or null
 218          */
 219         public static function newFromConds( $conditions ) {
 220                 $db = wfGetDB( DB_SLAVE );
 221                 $row = Revision::loadFromConds( $db, $conditions );
 222                 if( is_null( $row ) && wfGetLB()->getServerCount() > 1 ) {
 223                         $dbw = wfGetDB( DB_MASTER );
 224                         $row = Revision::loadFromConds( $dbw, $conditions );
 225                 }
 226                 return $row;
 227         }
 228
 229         /**
 230          * Given a set of conditions, fetch a revision from
 231          * the given database connection.
 232          *
 233          * @param $db DatabaseBase
 234          * @param $conditions Array
 235          * @return Revision or null
 236          */
 237         private static function loadFromConds( $db, $conditions ) {
 238                 $res = Revision::fetchFromConds( $db, $conditions );
 239                 if( $res ) {
 240                         $row = $res->fetchObject();
 241                         $res->free();
 242                         if( $row ) {
 243                                 $ret = new Revision( $row );
 244                                 return $ret;
 245                         }
 246                 }
 247                 $ret = null;
 248                 return $ret;
 249         }
 250
 251         /**
 252          * Return a wrapper for a series of database rows to
 253          * fetch all of a given page's revisions in turn.
 254          * Each row can be fed to the constructor to get objects.
 255          *
 256          * @param $title Title
 257          * @return ResultWrapper
 258          */
 259         public static function fetchRevision( $title ) {
 260                 return Revision::fetchFromConds(
 261                         wfGetDB( DB_SLAVE ),
 262                         array( 'rev_id=page_latest',
 263                                    'page_namespace' => $title->getNamespace(),
 264                                    'page_title'     => $title->getDBkey(),
 265                                    'page_id=rev_page' ) );
 266         }
 267
 268         /**
 269          * Given a set of conditions, return a ResultWrapper
 270          * which will return matching database rows with the
 271          * fields necessary to build Revision objects.
 272          *
 273          * @param $db DatabaseBase
 274          * @param $conditions Array
 275          * @return ResultWrapper
 276          */
 277         private static function fetchFromConds( $db, $conditions ) {
 278                 $fields = self::selectFields();
 279                 $fields[] = 'page_namespace';
 280                 $fields[] = 'page_title';
 281                 $fields[] = 'page_latest';
 282                 return $db->select(
 283                         array( 'page', 'revision' ),
 284                         $fields,
 285                         $conditions,
 286                         __METHOD__,
 287                         array( 'LIMIT' => 1 ) );
 288         }
 289
 290         /**
 291          * Return the list of revision fields that should be selected to create
 292          * a new revision.
 293          */
 294         public static function selectFields() {
 295                 return array(
 296                         'rev_id',
 297                         'rev_page',
 298                         'rev_text_id',
 299                         'rev_timestamp',
 300                         'rev_comment',
 301                         'rev_user_text,'.
 302                         'rev_user',
 303                         'rev_minor_edit',
 304                         'rev_deleted',
 305                         'rev_len',
 306                         'rev_parent_id',
 307                         'rev_sha1'
 308                 );
 309         }
 310
 311         /**
 312          * Return the list of text fields that should be selected to read the
 313          * revision text
 314          */
 315         static function selectTextFields() {
 316                 return array(
 317                         'old_text',
 318                         'old_flags'
 319                 );
 320         }
 321
 322         /**
 323          * Return the list of page fields that should be selected from page table
 324          */
 325         static function selectPageFields() {
 326                 return array(
 327                         'page_namespace',
 328                         'page_title',
 329                         'page_latest'
 330                 );
 331         }
 332
 333         /**
 334          * Constructor
 335          *
 336          * @param $row Mixed: either a database row or an array
 337          * @access private
 338          */
 339         function __construct( $row ) {
 340                 if( is_object( $row ) ) {
 341                         $this->mId        = intval( $row->rev_id );
 342                         $this->mPage      = intval( $row->rev_page );
 343                         $this->mTextId    = intval( $row->rev_text_id );
 344                         $this->mComment   =         $row->rev_comment;
 345                         $this->mUserText  =         $row->rev_user_text;
 346                         $this->mUser      = intval( $row->rev_user );
 347                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 348                         $this->mTimestamp =         $row->rev_timestamp;
 349                         $this->mDeleted   = intval( $row->rev_deleted );
 350
 351                         if( !isset( $row->rev_parent_id ) ) {
 352                                 $this->mParentId = is_null($row->rev_parent_id) ? null : 0;
 353                         } else {
 354                                 $this->mParentId  = intval( $row->rev_parent_id );
 355                         }
 356
 357                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 358                                 $this->mSize = null;
 359                         } else {
 360                                 $this->mSize = intval( $row->rev_len );
 361                         }
 362
 363                         if ( !isset( $row->rev_sha1 ) ) {
 364                                 $this->mSha1 = null;
 365                         } else {
 366                                 $this->mSha1 = $row->rev_sha1;
 367                         }
 368
 369                         if( isset( $row->page_latest ) ) {
 370                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 371                                 $this->mTitle = Title::newFromRow( $row );
 372                         } else {
 373                                 $this->mCurrent = false;
 374                                 $this->mTitle = null;
 375                         }
 376
 377                         // Lazy extraction...
 378                         $this->mText      = null;
 379                         if( isset( $row->old_text ) ) {
 380                                 $this->mTextRow = $row;
 381                         } else {
 382                                 // 'text' table row entry will be lazy-loaded
 383                                 $this->mTextRow = null;
 384                         }
 385                 } elseif( is_array( $row ) ) {
 386                         // Build a new revision to be saved...
 387                         global $wgUser; // ugh
 388
 389                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 390                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 391                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 392                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 393                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 394                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 395                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 396                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 397                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 398                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 399                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 400
 401                         // Enforce spacing trimming on supplied text
 402                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 403                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 404                         $this->mTextRow   = null;
 405
 406                         $this->mTitle     = null; # Load on demand if needed
 407                         $this->mCurrent   = false;
 408                         # If we still have no len_size, see it we have the text to figure it out
 409                         if ( !$this->mSize )
 410                                 $this->mSize      = is_null( $this->mText ) ? null : strlen( $this->mText );
 411                 } else {
 412                         throw new MWException( 'Revision constructor passed invalid row format.' );
 413                 }
 414                 $this->mUnpatrolled = null;
 415         }
 416
 417         /**
 418          * Get revision ID
 419          *
 420          * @return Integer
 421          */
 422         public function getId() {
 423                 return $this->mId;
 424         }
 425
 426         /**
 427          * Get text row ID
 428          *
 429          * @return Integer
 430          */
 431         public function getTextId() {
 432                 return $this->mTextId;
 433         }
 434
 435         /**
 436          * Get parent revision ID (the original previous page revision)
 437          *
 438          * @return Integer
 439          */
 440         public function getParentId() {
 441                 return $this->mParentId;
 442         }
 443
 444         /**
 445          * Returns the length of the text in this revision, or null if unknown.
 446          *
 447          * @return Integer
 448          */
 449         public function getSize() {
 450                 return $this->mSize;
 451         }
 452
 453         /**
 454          * Returns the title of the page associated with this entry.
 455          *
 456          * @return Title
 457          */
 458         public function getTitle() {
 459                 if( isset( $this->mTitle ) ) {
 460                         return $this->mTitle;
 461                 }
 462                 $dbr = wfGetDB( DB_SLAVE );
 463                 $row = $dbr->selectRow(
 464                         array( 'page', 'revision' ),
 465                         array( 'page_namespace', 'page_title' ),
 466                         array( 'page_id=rev_page',
 467                                    'rev_id' => $this->mId ),
 468                         'Revision::getTitle' );
 469                 if( $row ) {
 470                         $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 471                 }
 472                 return $this->mTitle;
 473         }
 474
 475         /**
 476          * Set the title of the revision
 477          *
 478          * @param $title Title
 479          */
 480         public function setTitle( $title ) {
 481                 $this->mTitle = $title;
 482         }
 483
 484         /**
 485          * Get the page ID
 486          *
 487          * @return Integer
 488          */
 489         public function getPage() {
 490                 return $this->mPage;
 491         }
 492
 493         /**
 494          * Fetch revision's user id if it's available to the specified audience.
 495          * If the specified audience does not have access to it, zero will be
 496          * returned.
 497          *
 498          * @param $audience Integer: one of:
 499          *      Revision::FOR_PUBLIC       to be displayed to all users
 500          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 501          *      Revision::RAW              get the ID regardless of permissions
 502          *
 503          *
 504          * @return Integer
 505          */
 506         public function getUser( $audience = self::FOR_PUBLIC ) {
 507                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 508                         return 0;
 509                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 510                         return 0;
 511                 } else {
 512                         return $this->mUser;
 513                 }
 514         }
 515
 516         /**
 517          * Fetch revision's user id without regard for the current user's permissions
 518          *
 519          * @return String
 520          */
 521         public function getRawUser() {
 522                 return $this->mUser;
 523         }
 524
 525         /**
 526          * Fetch revision's username if it's available to the specified audience.
 527          * If the specified audience does not have access to the username, an
 528          * empty string will be returned.
 529          *
 530          * @param $audience Integer: one of:
 531          *      Revision::FOR_PUBLIC       to be displayed to all users
 532          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 533          *      Revision::RAW              get the text regardless of permissions
 534          *
 535          * @return string
 536          */
 537         public function getUserText( $audience = self::FOR_PUBLIC ) {
 538                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 539                         return '';
 540                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER ) ) {
 541                         return '';
 542                 } else {
 543                         return $this->mUserText;
 544                 }
 545         }
 546
 547         /**
 548          * Fetch revision's username without regard for view restrictions
 549          *
 550          * @return String
 551          */
 552         public function getRawUserText() {
 553                 return $this->mUserText;
 554         }
 555
 556         /**
 557          * Fetch revision comment if it's available to the specified audience.
 558          * If the specified audience does not have access to the comment, an
 559          * empty string will be returned.
 560          *
 561          * @param $audience Integer: one of:
 562          *      Revision::FOR_PUBLIC       to be displayed to all users
 563          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 564          *      Revision::RAW              get the text regardless of permissions
 565          *
 566          * @return String
 567          */
 568         function getComment( $audience = self::FOR_PUBLIC ) {
 569                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 570                         return '';
 571                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT ) ) {
 572                         return '';
 573                 } else {
 574                         return $this->mComment;
 575                 }
 576         }
 577
 578         /**
 579          * Fetch revision comment without regard for the current user's permissions
 580          *
 581          * @return String
 582          */
 583         public function getRawComment() {
 584                 return $this->mComment;
 585         }
 586
 587         /**
 588          * @return Boolean
 589          */
 590         public function isMinor() {
 591                 return (bool)$this->mMinorEdit;
 592         }
 593
 594         /**
 595          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 596          */
 597         public function isUnpatrolled() {
 598                 if( $this->mUnpatrolled !== null ) {
 599                         return $this->mUnpatrolled;
 600                 }
 601                 $dbr = wfGetDB( DB_SLAVE );
 602                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 603                         'rc_id',
 604                         array( // Add redundant user,timestamp condition so we can use the existing index
 605                                 'rc_user_text'  => $this->getRawUserText(),
 606                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 607                                 'rc_this_oldid' => $this->getId(),
 608                                 'rc_patrolled'  => 0
 609                         ),
 610                         __METHOD__
 611                 );
 612                 return (int)$this->mUnpatrolled;
 613         }
 614
 615         /**
 616          * @param $field int one of DELETED_* bitfield constants
 617          *
 618          * @return Boolean
 619          */
 620         public function isDeleted( $field ) {
 621                 return ( $this->mDeleted & $field ) == $field;
 622         }
 623
 624         /**
 625          * Get the deletion bitfield of the revision
 626          *
 627          * @return int
 628          */
 629         public function getVisibility() {
 630                 return (int)$this->mDeleted;
 631         }
 632
 633         /**
 634          * Fetch revision text if it's available to the specified audience.
 635          * If the specified audience does not have the ability to view this
 636          * revision, an empty string will be returned.
 637          *
 638          * @param $audience Integer: one of:
 639          *      Revision::FOR_PUBLIC       to be displayed to all users
 640          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 641          *      Revision::RAW              get the text regardless of permissions
 642          *
 643          * @return String
 644          */
 645         public function getText( $audience = self::FOR_PUBLIC ) {
 646                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 647                         return '';
 648                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT ) ) {
 649                         return '';
 650                 } else {
 651                         return $this->getRawText();
 652                 }
 653         }
 654
 655         /**
 656          * Alias for getText(Revision::FOR_THIS_USER)
 657          *
 658          * @deprecated since 1.17
 659          * @return String
 660          */
 661         public function revText() {
 662                 wfDeprecated( __METHOD__ );
 663                 return $this->getText( self::FOR_THIS_USER );
 664         }
 665
 666         /**
 667          * Fetch revision text without regard for view restrictions
 668          *
 669          * @return String
 670          */
 671         public function getRawText() {
 672                 if( is_null( $this->mText ) ) {
 673                         // Revision text is immutable. Load on demand:
 674                         $this->mText = $this->loadText();
 675                 }
 676                 return $this->mText;
 677         }
 678
 679         /**
 680          * @return String
 681          */
 682         public function getTimestamp() {
 683                 return wfTimestamp( TS_MW, $this->mTimestamp );
 684         }
 685
 686         /**
 687          * @return Boolean
 688          */
 689         public function isCurrent() {
 690                 return $this->mCurrent;
 691         }
 692
 693         /**
 694          * Get previous revision for this title
 695          *
 696          * @return Revision or null
 697          */
 698         public function getPrevious() {
 699                 if( $this->getTitle() ) {
 700                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 701                         if( $prev ) {
 702                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 703                         }
 704                 }
 705                 return null;
 706         }
 707
 708         /**
 709          * Get next revision for this title
 710          *
 711          * @return Revision or null
 712          */
 713         public function getNext() {
 714                 if( $this->getTitle() ) {
 715                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 716                         if ( $next ) {
 717                                 return Revision::newFromTitle( $this->getTitle(), $next );
 718                         }
 719                 }
 720                 return null;
 721         }
 722
 723         /**
 724          * Get previous revision Id for this page_id
 725          * This is used to populate rev_parent_id on save
 726          *
 727          * @param $db DatabaseBase
 728          * @return Integer
 729          */
 730         private function getPreviousRevisionId( $db ) {
 731                 if( is_null( $this->mPage ) ) {
 732                         return 0;
 733                 }
 734                 # Use page_latest if ID is not given
 735                 if( !$this->mId ) {
 736                         $prevId = $db->selectField( 'page', 'page_latest',
 737                                 array( 'page_id' => $this->mPage ),
 738                                 __METHOD__ );
 739                 } else {
 740                         $prevId = $db->selectField( 'revision', 'rev_id',
 741                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 742                                 __METHOD__,
 743                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 744                 }
 745                 return intval( $prevId );
 746         }
 747
 748         /**
 749           * Get revision text associated with an old or archive row
 750           * $row is usually an object from wfFetchRow(), both the flags and the text
 751           * field must be included
 752           *
 753           * @param $row Object: the text data
 754           * @param $prefix String: table prefix (default 'old_')
 755           * @return String: text the text requested or false on failure
 756           */
 757         public static function getRevisionText( $row, $prefix = 'old_' ) {
 758                 wfProfileIn( __METHOD__ );
 759
 760                 # Get data
 761                 $textField = $prefix . 'text';
 762                 $flagsField = $prefix . 'flags';
 763
 764                 if( isset( $row->$flagsField ) ) {
 765                         $flags = explode( ',', $row->$flagsField );
 766                 } else {
 767                         $flags = array();
 768                 }
 769
 770                 if( isset( $row->$textField ) ) {
 771                         $text = $row->$textField;
 772                 } else {
 773                         wfProfileOut( __METHOD__ );
 774                         return false;
 775                 }
 776
 777                 # Use external methods for external objects, text in table is URL-only then
 778                 if ( in_array( 'external', $flags ) ) {
 779                         $url = $text;
 780                         $parts = explode( '://', $url, 2 );
 781                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 782                                 wfProfileOut( __METHOD__ );
 783                                 return false;
 784                         }
 785                         $text = ExternalStore::fetchFromURL( $url );
 786                 }
 787
 788                 // If the text was fetched without an error, convert it
 789                 if ( $text !== false ) {
 790                         if( in_array( 'gzip', $flags ) ) {
 791                                 # Deal with optional compression of archived pages.
 792                                 # This can be done periodically via maintenance/compressOld.php, and
 793                                 # as pages are saved if $wgCompressRevisions is set.
 794                                 $text = gzinflate( $text );
 795                         }
 796
 797                         if( in_array( 'object', $flags ) ) {
 798                                 # Generic compressed storage
 799                                 $obj = unserialize( $text );
 800                                 if ( !is_object( $obj ) ) {
 801                                         // Invalid object
 802                                         wfProfileOut( __METHOD__ );
 803                                         return false;
 804                                 }
 805                                 $text = $obj->getText();
 806                         }
 807
 808                         global $wgLegacyEncoding;
 809                         if( $text !== false && $wgLegacyEncoding
 810                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 811                         {
 812                                 # Old revisions kept around in a legacy encoding?
 813                                 # Upconvert on demand.
 814                                 # ("utf8" checked for compatibility with some broken
 815                                 #  conversion scripts 2008-12-30)
 816                                 global $wgContLang;
 817                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 818                         }
 819                 }
 820                 wfProfileOut( __METHOD__ );
 821                 return $text;
 822         }
 823
 824         /**
 825          * If $wgCompressRevisions is enabled, we will compress data.
 826          * The input string is modified in place.
 827          * Return value is the flags field: contains 'gzip' if the
 828          * data is compressed, and 'utf-8' if we're saving in UTF-8
 829          * mode.
 830          *
 831          * @param $text Mixed: reference to a text
 832          * @return String
 833          */
 834         public static function compressRevisionText( &$text ) {
 835                 global $wgCompressRevisions;
 836                 $flags = array();
 837
 838                 # Revisions not marked this way will be converted
 839                 # on load if $wgLegacyCharset is set in the future.
 840                 $flags[] = 'utf-8';
 841
 842                 if( $wgCompressRevisions ) {
 843                         if( function_exists( 'gzdeflate' ) ) {
 844                                 $text = gzdeflate( $text );
 845                                 $flags[] = 'gzip';
 846                         } else {
 847                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 848                         }
 849                 }
 850                 return implode( ',', $flags );
 851         }
 852
 853         /**
 854          * Insert a new revision into the database, returning the new revision ID
 855          * number on success and dies horribly on failure.
 856          *
 857          * @param $dbw DatabaseBase: (master connection)
 858          * @return Integer
 859          */
 860         public function insertOn( $dbw ) {
 861                 global $wgDefaultExternalStore;
 862
 863                 wfProfileIn( __METHOD__ );
 864
 865                 $data = $this->mText;
 866                 $flags = Revision::compressRevisionText( $data );
 867
 868                 # Write to external storage if required
 869                 if( $wgDefaultExternalStore ) {
 870                         // Store and get the URL
 871                         $data = ExternalStore::insertToDefault( $data );
 872                         if( !$data ) {
 873                                 throw new MWException( "Unable to store text to external storage" );
 874                         }
 875                         if( $flags ) {
 876                                 $flags .= ',';
 877                         }
 878                         $flags .= 'external';
 879                 }
 880
 881                 # Record the text (or external storage URL) to the text table
 882                 if( !isset( $this->mTextId ) ) {
 883                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 884                         $dbw->insert( 'text',
 885                                 array(
 886                                         'old_id'    => $old_id,
 887                                         'old_text'  => $data,
 888                                         'old_flags' => $flags,
 889                                 ), __METHOD__
 890                         );
 891                         $this->mTextId = $dbw->insertId();
 892                 }
 893
 894                 if ( $this->mComment === null ) $this->mComment = "";
 895
 896                 # Record the edit in revisions
 897                 $rev_id = isset( $this->mId )
 898                         ? $this->mId
 899                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 900                 $dbw->insert( 'revision',
 901                         array(
 902                                 'rev_id'         => $rev_id,
 903                                 'rev_page'       => $this->mPage,
 904                                 'rev_text_id'    => $this->mTextId,
 905                                 'rev_comment'    => $this->mComment,
 906                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 907                                 'rev_user'       => $this->mUser,
 908                                 'rev_user_text'  => $this->mUserText,
 909                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 910                                 'rev_deleted'    => $this->mDeleted,
 911                                 'rev_len'        => $this->mSize,
 912                                 'rev_parent_id'  => is_null( $this->mParentId )
 913                                         ? $this->getPreviousRevisionId( $dbw )
 914                                         : $this->mParentId,
 915                                 'rev_sha1'       => is_null( $this->mSha1 )
 916                                         ? Revision::base36Sha1( $this->mText )
 917                                         : $this->mSha1
 918                         ), __METHOD__
 919                 );
 920
 921                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 922
 923                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 924
 925                 wfProfileOut( __METHOD__ );
 926                 return $this->mId;
 927         }
 928
 929         /**
 930          * Get the base 36 SHA-1 value for a string of text
 931          * @param $text String
 932          * @return String
 933          */
 934         public static function base36Sha1( $text ) {
 935                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
 936         }
 937
 938         /**
 939          * Lazy-load the revision's text.
 940          * Currently hardcoded to the 'text' table storage engine.
 941          *
 942          * @return String
 943          */
 944         protected function loadText() {
 945                 wfProfileIn( __METHOD__ );
 946
 947                 // Caching may be beneficial for massive use of external storage
 948                 global $wgRevisionCacheExpiry, $wgMemc;
 949                 $textId = $this->getTextId();
 950                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
 951                 if( $wgRevisionCacheExpiry ) {
 952                         $text = $wgMemc->get( $key );
 953                         if( is_string( $text ) ) {
 954                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
 955                                 wfProfileOut( __METHOD__ );
 956                                 return $text;
 957                         }
 958                 }
 959
 960                 // If we kept data for lazy extraction, use it now...
 961                 if ( isset( $this->mTextRow ) ) {
 962                         $row = $this->mTextRow;
 963                         $this->mTextRow = null;
 964                 } else {
 965                         $row = null;
 966                 }
 967
 968                 if( !$row ) {
 969                         // Text data is immutable; check slaves first.
 970                         $dbr = wfGetDB( DB_SLAVE );
 971                         $row = $dbr->selectRow( 'text',
 972                                 array( 'old_text', 'old_flags' ),
 973                                 array( 'old_id' => $this->getTextId() ),
 974                                 __METHOD__ );
 975                 }
 976
 977                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
 978                         // Possible slave lag!
 979                         $dbw = wfGetDB( DB_MASTER );
 980                         $row = $dbw->selectRow( 'text',
 981                                 array( 'old_text', 'old_flags' ),
 982                                 array( 'old_id' => $this->getTextId() ),
 983                                 __METHOD__ );
 984                 }
 985
 986                 $text = self::getRevisionText( $row );
 987
 988                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
 989                 if( $wgRevisionCacheExpiry && $text !== false ) {
 990                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 991                 }
 992
 993                 wfProfileOut( __METHOD__ );
 994
 995                 return $text;
 996         }
 997
 998         /**
 999          * Create a new null-revision for insertion into a page's
1000          * history. This will not re-save the text, but simply refer
1001          * to the text from the previous version.
1002          *
1003          * Such revisions can for instance identify page rename
1004          * operations and other such meta-modifications.
1005          *
1006          * @param $dbw DatabaseBase
1007          * @param $pageId Integer: ID number of the page to read from
1008          * @param $summary String: revision's summary
1009          * @param $minor Boolean: whether the revision should be considered as minor
1010          * @return Revision|null on error
1011          */
1012         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1013                 wfProfileIn( __METHOD__ );
1014
1015                 $current = $dbw->selectRow(
1016                         array( 'page', 'revision' ),
1017                         array( 'page_latest', 'rev_text_id', 'rev_len' ),
1018                         array(
1019                                 'page_id' => $pageId,
1020                                 'page_latest=rev_id',
1021                                 ),
1022                         __METHOD__ );
1023
1024                 if( $current ) {
1025                         $revision = new Revision( array(
1026                                 'page'       => $pageId,
1027                                 'comment'    => $summary,
1028                                 'minor_edit' => $minor,
1029                                 'text_id'    => $current->rev_text_id,
1030                                 'parent_id'  => $current->page_latest,
1031                                 'len'        => $current->rev_len
1032                                 ) );
1033                 } else {
1034                         $revision = null;
1035                 }
1036
1037                 wfProfileOut( __METHOD__ );
1038                 return $revision;
1039         }
1040
1041         /**
1042          * Determine if the current user is allowed to view a particular
1043          * field of this revision, if it's marked as deleted.
1044          *
1045          * @param $field Integer:one of self::DELETED_TEXT,
1046          *                              self::DELETED_COMMENT,
1047          *                              self::DELETED_USER
1048          * @return Boolean
1049          */
1050         public function userCan( $field ) {
1051                 return self::userCanBitfield( $this->mDeleted, $field );
1052         }
1053
1054         /**
1055          * Determine if the current user is allowed to view a particular
1056          * field of this revision, if it's marked as deleted. This is used
1057          * by various classes to avoid duplication.
1058          *
1059          * @param $bitfield Integer: current field
1060          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1061          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1062          *                               self::DELETED_USER = File::DELETED_USER
1063          * @return Boolean
1064          */
1065         public static function userCanBitfield( $bitfield, $field ) {
1066                 if( $bitfield & $field ) { // aspect is deleted
1067                         global $wgUser;
1068                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1069                                 $permission = 'suppressrevision';
1070                         } elseif ( $field & self::DELETED_TEXT ) {
1071                                 $permission = 'deletedtext';
1072                         } else {
1073                                 $permission = 'deletedhistory';
1074                         }
1075                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1076                         return $wgUser->isAllowed( $permission );
1077                 } else {
1078                         return true;
1079                 }
1080         }
1081
1082         /**
1083          * Get rev_timestamp from rev_id, without loading the rest of the row
1084          *
1085          * @param $title Title
1086          * @param $id Integer
1087          * @return String
1088          */
1089         static function getTimestampFromId( $title, $id ) {
1090                 $dbr = wfGetDB( DB_SLAVE );
1091                 // Casting fix for DB2
1092                 if ( $id == '' ) {
1093                         $id = 0;
1094                 }
1095                 $conds = array( 'rev_id' => $id );
1096                 $conds['rev_page'] = $title->getArticleId();
1097                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1098                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1099                         # Not in slave, try master
1100                         $dbw = wfGetDB( DB_MASTER );
1101                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1102                 }
1103                 return wfTimestamp( TS_MW, $timestamp );
1104         }
1105
1106         /**
1107          * Get count of revisions per page...not very efficient
1108          *
1109          * @param $db DatabaseBase
1110          * @param $id Integer: page id
1111          * @return Integer
1112          */
1113         static function countByPageId( $db, $id ) {
1114                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1115                         array( 'rev_page' => $id ), __METHOD__ );
1116                 if( $row ) {
1117                         return $row->revCount;
1118                 }
1119                 return 0;
1120         }
1121
1122         /**
1123          * Get count of revisions per page...not very efficient
1124          *
1125          * @param $db DatabaseBase
1126          * @param $title Title
1127          * @return Integer
1128          */
1129         static function countByTitle( $db, $title ) {
1130                 $id = $title->getArticleId();
1131                 if( $id ) {
1132                         return Revision::countByPageId( $db, $id );
1133                 }
1134                 return 0;
1135         }
1136 }