includes/Revision.php

   1 <?php
   2
   3 /**
   4  * @todo document
   5  */
   6 class Revision {
   7         protected $mId;
   8         protected $mPage;
   9         protected $mUserText;
  10         protected $mOrigUserText;
  11         protected $mUser;
  12         protected $mMinorEdit;
  13         protected $mTimestamp;
  14         protected $mDeleted;
  15         protected $mSize;
  16         protected $mSha1;
  17         protected $mParentId;
  18         protected $mComment;
  19         protected $mText;
  20         protected $mTextRow;
  21         protected $mTitle;
  22         protected $mCurrent;
  23
  24         const DELETED_TEXT = 1;
  25         const DELETED_COMMENT = 2;
  26         const DELETED_USER = 4;
  27         const DELETED_RESTRICTED = 8;
  28         // Convenience field
  29         const SUPPRESSED_USER = 12;
  30         // Audience options for Revision::getText()
  31         const FOR_PUBLIC = 1;
  32         const FOR_THIS_USER = 2;
  33         const RAW = 3;
  34
  35         /**
  36          * Load a page revision from a given revision ID number.
  37          * Returns null if no such revision can be found.
  38          *
  39          * @param $id Integer
  40          * @return Revision or null
  41          */
  42         public static function newFromId( $id ) {
  43                 return Revision::newFromConds( array( 'rev_id' => intval( $id ) ) );
  44         }
  45
  46         /**
  47          * Load either the current, or a specified, revision
  48          * that's attached to a given title. If not attached
  49          * to that title, will return null.
  50          *
  51          * @param $title Title
  52          * @param $id Integer (optional)
  53          * @return Revision or null
  54          */
  55         public static function newFromTitle( $title, $id = 0 ) {
  56                 $conds = array(
  57                         'page_namespace' => $title->getNamespace(),
  58                         'page_title'     => $title->getDBkey()
  59                 );
  60                 if ( $id ) {
  61                         // Use the specified ID
  62                         $conds['rev_id'] = $id;
  63                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  64                         // Get the latest revision ID from the master
  65                         $dbw = wfGetDB( DB_MASTER );
  66                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  67                         if ( $latest === false ) {
  68                                 return null; // page does not exist
  69                         }
  70                         $conds['rev_id'] = $latest;
  71                 } else {
  72                         // Use a join to get the latest revision
  73                         $conds[] = 'rev_id=page_latest';
  74                 }
  75                 return Revision::newFromConds( $conds );
  76         }
  77
  78         /**
  79          * Load either the current, or a specified, revision
  80          * that's attached to a given page ID.
  81          * Returns null if no such revision can be found.
  82          *
  83          * @param $revId Integer
  84          * @param $pageId Integer (optional)
  85          * @return Revision or null
  86          */
  87         public static function newFromPageId( $pageId, $revId = 0 ) {
  88                 $conds = array( 'page_id' => $pageId );
  89                 if ( $revId ) {
  90                         $conds['rev_id'] = $revId;
  91                 } elseif ( wfGetLB()->getServerCount() > 1 ) {
  92                         // Get the latest revision ID from the master
  93                         $dbw = wfGetDB( DB_MASTER );
  94                         $latest = $dbw->selectField( 'page', 'page_latest', $conds, __METHOD__ );
  95                         if ( $latest === false ) {
  96                                 return null; // page does not exist
  97                         }
  98                         $conds['rev_id'] = $latest;
  99                 } else {
 100                         $conds[] = 'rev_id = page_latest';
 101                 }
 102                 return Revision::newFromConds( $conds );
 103         }
 104
 105         /**
 106          * Make a fake revision object from an archive table row. This is queried
 107          * for permissions or even inserted (as in Special:Undelete)
 108          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 109          *
 110          * @param $row
 111          * @param $overrides array
 112          *
 113          * @return Revision
 114          */
 115         public static function newFromArchiveRow( $row, $overrides = array() ) {
 116                 $attribs = $overrides + array(
 117                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 118                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 119                         'comment'    => $row->ar_comment,
 120                         'user'       => $row->ar_user,
 121                         'user_text'  => $row->ar_user_text,
 122                         'timestamp'  => $row->ar_timestamp,
 123                         'minor_edit' => $row->ar_minor_edit,
 124                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 125                         'deleted'    => $row->ar_deleted,
 126                         'len'        => $row->ar_len,
 127                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 128                 );
 129                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 130                         // Pre-1.5 ar_text row
 131                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 132                         if ( $attribs['text'] === false ) {
 133                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 134                         }
 135                 }
 136                 return new self( $attribs );
 137         }
 138
 139         /**
 140          * @since 1.19
 141          *
 142          * @param $row
 143          * @return Revision
 144          */
 145         public static function newFromRow( $row ) {
 146                 return new self( $row );
 147         }
 148
 149         /**
 150          * Load a page revision from a given revision ID number.
 151          * Returns null if no such revision can be found.
 152          *
 153          * @param $db DatabaseBase
 154          * @param $id Integer
 155          * @return Revision or null
 156          */
 157         public static function loadFromId( $db, $id ) {
 158                 return Revision::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 159         }
 160
 161         /**
 162          * Load either the current, or a specified, revision
 163          * that's attached to a given page. If not attached
 164          * to that page, will return null.
 165          *
 166          * @param $db DatabaseBase
 167          * @param $pageid Integer
 168          * @param $id Integer
 169          * @return Revision or null
 170          */
 171         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 172                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 173                 if( $id ) {
 174                         $conds['rev_id'] = intval( $id );
 175                 } else {
 176                         $conds[] = 'rev_id=page_latest';
 177                 }
 178                 return Revision::loadFromConds( $db, $conds );
 179         }
 180
 181         /**
 182          * Load either the current, or a specified, revision
 183          * that's attached to a given page. If not attached
 184          * to that page, will return null.
 185          *
 186          * @param $db DatabaseBase
 187          * @param $title Title
 188          * @param $id Integer
 189          * @return Revision or null
 190          */
 191         public static function loadFromTitle( $db, $title, $id = 0 ) {
 192                 if( $id ) {
 193                         $matchId = intval( $id );
 194                 } else {
 195                         $matchId = 'page_latest';
 196                 }
 197                 return Revision::loadFromConds( $db,
 198                         array( "rev_id=$matchId",
 199                                    'page_namespace' => $title->getNamespace(),
 200                                    'page_title'     => $title->getDBkey() )
 201                 );
 202         }
 203
 204         /**
 205          * Load the revision for the given title with the given timestamp.
 206          * WARNING: Timestamps may in some circumstances not be unique,
 207          * so this isn't the best key to use.
 208          *
 209          * @param $db DatabaseBase
 210          * @param $title Title
 211          * @param $timestamp String
 212          * @return Revision or null
 213          */
 214         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 215                 return Revision::loadFromConds( $db,
 216                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 217                                    'page_namespace' => $title->getNamespace(),
 218                                    'page_title'     => $title->getDBkey() )
 219                 );
 220         }
 221
 222         /**
 223          * Given a set of conditions, fetch a revision.
 224          *
 225          * @param $conditions Array
 226          * @return Revision or null
 227          */
 228         public static function newFromConds( $conditions ) {
 229                 $db = wfGetDB( DB_SLAVE );
 230                 $rev = Revision::loadFromConds( $db, $conditions );
 231                 if( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 232                         $dbw = wfGetDB( DB_MASTER );
 233                         $rev = Revision::loadFromConds( $dbw, $conditions );
 234                 }
 235                 return $rev;
 236         }
 237
 238         /**
 239          * Given a set of conditions, fetch a revision from
 240          * the given database connection.
 241          *
 242          * @param $db DatabaseBase
 243          * @param $conditions Array
 244          * @return Revision or null
 245          */
 246         private static function loadFromConds( $db, $conditions ) {
 247                 $res = Revision::fetchFromConds( $db, $conditions );
 248                 if( $res ) {
 249                         $row = $res->fetchObject();
 250                         if( $row ) {
 251                                 $ret = new Revision( $row );
 252                                 return $ret;
 253                         }
 254                 }
 255                 $ret = null;
 256                 return $ret;
 257         }
 258
 259         /**
 260          * Return a wrapper for a series of database rows to
 261          * fetch all of a given page's revisions in turn.
 262          * Each row can be fed to the constructor to get objects.
 263          *
 264          * @param $title Title
 265          * @return ResultWrapper
 266          */
 267         public static function fetchRevision( $title ) {
 268                 return Revision::fetchFromConds(
 269                         wfGetDB( DB_SLAVE ),
 270                         array( 'rev_id=page_latest',
 271                                    'page_namespace' => $title->getNamespace(),
 272                                    'page_title'     => $title->getDBkey() )
 273                 );
 274         }
 275
 276         /**
 277          * Given a set of conditions, return a ResultWrapper
 278          * which will return matching database rows with the
 279          * fields necessary to build Revision objects.
 280          *
 281          * @param $db DatabaseBase
 282          * @param $conditions Array
 283          * @return ResultWrapper
 284          */
 285         private static function fetchFromConds( $db, $conditions ) {
 286                 $fields = array_merge(
 287                         self::selectFields(),
 288                         self::selectPageFields(),
 289                         self::selectUserFields()
 290                 );
 291                 return $db->select(
 292                         array( 'revision', 'page', 'user' ),
 293                         $fields,
 294                         $conditions,
 295                         __METHOD__,
 296                         array( 'LIMIT' => 1 ),
 297                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 298                 );
 299         }
 300
 301         /**
 302          * Return the value of a select() JOIN conds array for the user table.
 303          * This will get user table rows for logged-in users.
 304          * @return Array
 305          */
 306         public static function userJoinCond() {
 307                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 308         }
 309
 310         /**
 311          * Return the value of a select() page conds array for the paeg table.
 312          * This will assure that the revision(s) are not orphaned from live pages.
 313          * @return Array
 314          */
 315         public static function pageJoinCond() {
 316                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 317         }
 318
 319         /**
 320          * Return the list of revision fields that should be selected to create
 321          * a new revision.
 322          */
 323         public static function selectFields() {
 324                 return array(
 325                         'rev_id',
 326                         'rev_page',
 327                         'rev_text_id',
 328                         'rev_timestamp',
 329                         'rev_comment',
 330                         'rev_user_text',
 331                         'rev_user',
 332                         'rev_minor_edit',
 333                         'rev_deleted',
 334                         'rev_len',
 335                         'rev_parent_id',
 336                         'rev_sha1'
 337                 );
 338         }
 339
 340         /**
 341          * Return the list of text fields that should be selected to read the
 342          * revision text
 343          */
 344         public static function selectTextFields() {
 345                 return array(
 346                         'old_text',
 347                         'old_flags'
 348                 );
 349         }
 350
 351         /**
 352          * Return the list of page fields that should be selected from page table
 353          */
 354         public static function selectPageFields() {
 355                 return array(
 356                         'page_namespace',
 357                         'page_title',
 358                         'page_latest'
 359                 );
 360         }
 361
 362         /**
 363          * Return the list of user fields that should be selected from user table
 364          */
 365         public static function selectUserFields() {
 366                 return array( 'user_name' );
 367         }
 368
 369         /**
 370          * Constructor
 371          *
 372          * @param $row Mixed: either a database row or an array
 373          * @access private
 374          */
 375         function __construct( $row ) {
 376                 if( is_object( $row ) ) {
 377                         $this->mId        = intval( $row->rev_id );
 378                         $this->mPage      = intval( $row->rev_page );
 379                         $this->mTextId    = intval( $row->rev_text_id );
 380                         $this->mComment   =         $row->rev_comment;
 381                         $this->mUser      = intval( $row->rev_user );
 382                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 383                         $this->mTimestamp =         $row->rev_timestamp;
 384                         $this->mDeleted   = intval( $row->rev_deleted );
 385
 386                         if( !isset( $row->rev_parent_id ) ) {
 387                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 388                         } else {
 389                                 $this->mParentId  = intval( $row->rev_parent_id );
 390                         }
 391
 392                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 393                                 $this->mSize = null;
 394                         } else {
 395                                 $this->mSize = intval( $row->rev_len );
 396                         }
 397
 398                         if ( !isset( $row->rev_sha1 ) ) {
 399                                 $this->mSha1 = null;
 400                         } else {
 401                                 $this->mSha1 = $row->rev_sha1;
 402                         }
 403
 404                         if( isset( $row->page_latest ) ) {
 405                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 406                                 $this->mTitle = Title::newFromRow( $row );
 407                         } else {
 408                                 $this->mCurrent = false;
 409                                 $this->mTitle = null;
 410                         }
 411
 412                         // Lazy extraction...
 413                         $this->mText      = null;
 414                         if( isset( $row->old_text ) ) {
 415                                 $this->mTextRow = $row;
 416                         } else {
 417                                 // 'text' table row entry will be lazy-loaded
 418                                 $this->mTextRow = null;
 419                         }
 420
 421                         // Use user_name for users and rev_user_text for IPs...
 422                         $this->mUserText = null; // lazy load if left null
 423                         if ( $this->mUser == 0 ) {
 424                                 $this->mUserText = $row->rev_user_text; // IP user
 425                         } elseif ( isset( $row->user_name ) ) {
 426                                 $this->mUserText = $row->user_name; // logged-in user
 427                         }
 428                         $this->mOrigUserText = $row->rev_user_text;
 429                 } elseif( is_array( $row ) ) {
 430                         // Build a new revision to be saved...
 431                         global $wgUser; // ugh
 432
 433                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 434                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 435                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 436                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 437                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 438                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 439                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 440                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 441                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 442                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 443                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 444
 445                         // Enforce spacing trimming on supplied text
 446                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 447                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 448                         $this->mTextRow   = null;
 449
 450                         $this->mTitle     = null; # Load on demand if needed
 451                         $this->mCurrent   = false;
 452                         # If we still have no length, see it we have the text to figure it out
 453                         if ( !$this->mSize ) {
 454                                 $this->mSize = is_null( $this->mText ) ? null : strlen( $this->mText );
 455                         }
 456                         # Same for sha1
 457                         if ( $this->mSha1 === null ) {
 458                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 459                         }
 460                 } else {
 461                         throw new MWException( 'Revision constructor passed invalid row format.' );
 462                 }
 463                 $this->mUnpatrolled = null;
 464         }
 465
 466         /**
 467          * Get revision ID
 468          *
 469          * @return Integer
 470          */
 471         public function getId() {
 472                 return $this->mId;
 473         }
 474
 475         /**
 476          * Get text row ID
 477          *
 478          * @return Integer
 479          */
 480         public function getTextId() {
 481                 return $this->mTextId;
 482         }
 483
 484         /**
 485          * Get parent revision ID (the original previous page revision)
 486          *
 487          * @return Integer
 488          */
 489         public function getParentId() {
 490                 return $this->mParentId;
 491         }
 492
 493         /**
 494          * Returns the length of the text in this revision, or null if unknown.
 495          *
 496          * @return Integer
 497          */
 498         public function getSize() {
 499                 return $this->mSize;
 500         }
 501
 502         /**
 503          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 504          *
 505          * @return String
 506          */
 507         public function getSha1() {
 508                 return $this->mSha1;
 509         }
 510
 511         /**
 512          * Returns the title of the page associated with this entry.
 513          *
 514          * @return Title
 515          */
 516         public function getTitle() {
 517                 if( isset( $this->mTitle ) ) {
 518                         return $this->mTitle;
 519                 }
 520                 $dbr = wfGetDB( DB_SLAVE );
 521                 $row = $dbr->selectRow(
 522                         array( 'page', 'revision' ),
 523                         array( 'page_namespace', 'page_title' ),
 524                         array( 'page_id=rev_page',
 525                                    'rev_id' => $this->mId ),
 526                         'Revision::getTitle' );
 527                 if( $row ) {
 528                         $this->mTitle = Title::makeTitle( $row->page_namespace, $row->page_title );
 529                 }
 530                 return $this->mTitle;
 531         }
 532
 533         /**
 534          * Set the title of the revision
 535          *
 536          * @param $title Title
 537          */
 538         public function setTitle( $title ) {
 539                 $this->mTitle = $title;
 540         }
 541
 542         /**
 543          * Get the page ID
 544          *
 545          * @return Integer
 546          */
 547         public function getPage() {
 548                 return $this->mPage;
 549         }
 550
 551         /**
 552          * Fetch revision's user id if it's available to the specified audience.
 553          * If the specified audience does not have access to it, zero will be
 554          * returned.
 555          *
 556          * @param $audience Integer: one of:
 557          *      Revision::FOR_PUBLIC       to be displayed to all users
 558          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 559          *      Revision::RAW              get the ID regardless of permissions
 560          * @param $user User object to check for, only if FOR_THIS_USER is passed
 561          *              to the $audience parameter
 562          * @return Integer
 563          */
 564         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 565                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 566                         return 0;
 567                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 568                         return 0;
 569                 } else {
 570                         return $this->mUser;
 571                 }
 572         }
 573
 574         /**
 575          * Fetch revision's user id without regard for the current user's permissions
 576          *
 577          * @return String
 578          */
 579         public function getRawUser() {
 580                 return $this->mUser;
 581         }
 582
 583         /**
 584          * Fetch revision's username if it's available to the specified audience.
 585          * If the specified audience does not have access to the username, an
 586          * empty string will be returned.
 587          *
 588          * @param $audience Integer: one of:
 589          *      Revision::FOR_PUBLIC       to be displayed to all users
 590          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 591          *      Revision::RAW              get the text regardless of permissions
 592          * @param $user User object to check for, only if FOR_THIS_USER is passed
 593          *              to the $audience parameter
 594          * @return string
 595          */
 596         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 597                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 598                         return '';
 599                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 600                         return '';
 601                 } else {
 602                         return $this->getRawUserText();
 603                 }
 604         }
 605
 606         /**
 607          * Fetch revision's username without regard for view restrictions
 608          *
 609          * @return String
 610          */
 611         public function getRawUserText() {
 612                 if ( $this->mUserText === null ) {
 613                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 614                         if ( $this->mUserText === false ) {
 615                                 # This shouldn't happen, but it can if the wiki was recovered
 616                                 # via importing revs and there is no user table entry yet.
 617                                 $this->mUserText = $this->mOrigUserText;
 618                         }
 619                 }
 620                 return $this->mUserText;
 621         }
 622
 623         /**
 624          * Fetch revision comment if it's available to the specified audience.
 625          * If the specified audience does not have access to the comment, an
 626          * empty string will be returned.
 627          *
 628          * @param $audience Integer: one of:
 629          *      Revision::FOR_PUBLIC       to be displayed to all users
 630          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 631          *      Revision::RAW              get the text regardless of permissions
 632          * @param $user User object to check for, only if FOR_THIS_USER is passed
 633          *              to the $audience parameter
 634          * @return String
 635          */
 636         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 637                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 638                         return '';
 639                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 640                         return '';
 641                 } else {
 642                         return $this->mComment;
 643                 }
 644         }
 645
 646         /**
 647          * Fetch revision comment without regard for the current user's permissions
 648          *
 649          * @return String
 650          */
 651         public function getRawComment() {
 652                 return $this->mComment;
 653         }
 654
 655         /**
 656          * @return Boolean
 657          */
 658         public function isMinor() {
 659                 return (bool)$this->mMinorEdit;
 660         }
 661
 662         /**
 663          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 664          */
 665         public function isUnpatrolled() {
 666                 if( $this->mUnpatrolled !== null ) {
 667                         return $this->mUnpatrolled;
 668                 }
 669                 $dbr = wfGetDB( DB_SLAVE );
 670                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 671                         'rc_id',
 672                         array( // Add redundant user,timestamp condition so we can use the existing index
 673                                 'rc_user_text'  => $this->getRawUserText(),
 674                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 675                                 'rc_this_oldid' => $this->getId(),
 676                                 'rc_patrolled'  => 0
 677                         ),
 678                         __METHOD__
 679                 );
 680                 return (int)$this->mUnpatrolled;
 681         }
 682
 683         /**
 684          * @param $field int one of DELETED_* bitfield constants
 685          *
 686          * @return Boolean
 687          */
 688         public function isDeleted( $field ) {
 689                 return ( $this->mDeleted & $field ) == $field;
 690         }
 691
 692         /**
 693          * Get the deletion bitfield of the revision
 694          *
 695          * @return int
 696          */
 697         public function getVisibility() {
 698                 return (int)$this->mDeleted;
 699         }
 700
 701         /**
 702          * Fetch revision text if it's available to the specified audience.
 703          * If the specified audience does not have the ability to view this
 704          * revision, an empty string will be returned.
 705          *
 706          * @param $audience Integer: one of:
 707          *      Revision::FOR_PUBLIC       to be displayed to all users
 708          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 709          *      Revision::RAW              get the text regardless of permissions
 710          * @param $user User object to check for, only if FOR_THIS_USER is passed
 711          *              to the $audience parameter
 712          * @return String
 713          */
 714         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 715                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 716                         return '';
 717                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 718                         return '';
 719                 } else {
 720                         return $this->getRawText();
 721                 }
 722         }
 723
 724         /**
 725          * Alias for getText(Revision::FOR_THIS_USER)
 726          *
 727          * @deprecated since 1.17
 728          * @return String
 729          */
 730         public function revText() {
 731                 wfDeprecated( __METHOD__ );
 732                 return $this->getText( self::FOR_THIS_USER );
 733         }
 734
 735         /**
 736          * Fetch revision text without regard for view restrictions
 737          *
 738          * @return String
 739          */
 740         public function getRawText() {
 741                 if( is_null( $this->mText ) ) {
 742                         // Revision text is immutable. Load on demand:
 743                         $this->mText = $this->loadText();
 744                 }
 745                 return $this->mText;
 746         }
 747
 748         /**
 749          * @return String
 750          */
 751         public function getTimestamp() {
 752                 return wfTimestamp( TS_MW, $this->mTimestamp );
 753         }
 754
 755         /**
 756          * @return Boolean
 757          */
 758         public function isCurrent() {
 759                 return $this->mCurrent;
 760         }
 761
 762         /**
 763          * Get previous revision for this title
 764          *
 765          * @return Revision or null
 766          */
 767         public function getPrevious() {
 768                 if( $this->getTitle() ) {
 769                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 770                         if( $prev ) {
 771                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 772                         }
 773                 }
 774                 return null;
 775         }
 776
 777         /**
 778          * Get next revision for this title
 779          *
 780          * @return Revision or null
 781          */
 782         public function getNext() {
 783                 if( $this->getTitle() ) {
 784                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 785                         if ( $next ) {
 786                                 return Revision::newFromTitle( $this->getTitle(), $next );
 787                         }
 788                 }
 789                 return null;
 790         }
 791
 792         /**
 793          * Get previous revision Id for this page_id
 794          * This is used to populate rev_parent_id on save
 795          *
 796          * @param $db DatabaseBase
 797          * @return Integer
 798          */
 799         private function getPreviousRevisionId( $db ) {
 800                 if( is_null( $this->mPage ) ) {
 801                         return 0;
 802                 }
 803                 # Use page_latest if ID is not given
 804                 if( !$this->mId ) {
 805                         $prevId = $db->selectField( 'page', 'page_latest',
 806                                 array( 'page_id' => $this->mPage ),
 807                                 __METHOD__ );
 808                 } else {
 809                         $prevId = $db->selectField( 'revision', 'rev_id',
 810                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 811                                 __METHOD__,
 812                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 813                 }
 814                 return intval( $prevId );
 815         }
 816
 817         /**
 818           * Get revision text associated with an old or archive row
 819           * $row is usually an object from wfFetchRow(), both the flags and the text
 820           * field must be included
 821           *
 822           * @param $row Object: the text data
 823           * @param $prefix String: table prefix (default 'old_')
 824           * @return String: text the text requested or false on failure
 825           */
 826         public static function getRevisionText( $row, $prefix = 'old_' ) {
 827                 wfProfileIn( __METHOD__ );
 828
 829                 # Get data
 830                 $textField = $prefix . 'text';
 831                 $flagsField = $prefix . 'flags';
 832
 833                 if( isset( $row->$flagsField ) ) {
 834                         $flags = explode( ',', $row->$flagsField );
 835                 } else {
 836                         $flags = array();
 837                 }
 838
 839                 if( isset( $row->$textField ) ) {
 840                         $text = $row->$textField;
 841                 } else {
 842                         wfProfileOut( __METHOD__ );
 843                         return false;
 844                 }
 845
 846                 # Use external methods for external objects, text in table is URL-only then
 847                 if ( in_array( 'external', $flags ) ) {
 848                         $url = $text;
 849                         $parts = explode( '://', $url, 2 );
 850                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 851                                 wfProfileOut( __METHOD__ );
 852                                 return false;
 853                         }
 854                         $text = ExternalStore::fetchFromURL( $url );
 855                 }
 856
 857                 // If the text was fetched without an error, convert it
 858                 if ( $text !== false ) {
 859                         if( in_array( 'gzip', $flags ) ) {
 860                                 # Deal with optional compression of archived pages.
 861                                 # This can be done periodically via maintenance/compressOld.php, and
 862                                 # as pages are saved if $wgCompressRevisions is set.
 863                                 $text = gzinflate( $text );
 864                         }
 865
 866                         if( in_array( 'object', $flags ) ) {
 867                                 # Generic compressed storage
 868                                 $obj = unserialize( $text );
 869                                 if ( !is_object( $obj ) ) {
 870                                         // Invalid object
 871                                         wfProfileOut( __METHOD__ );
 872                                         return false;
 873                                 }
 874                                 $text = $obj->getText();
 875                         }
 876
 877                         global $wgLegacyEncoding;
 878                         if( $text !== false && $wgLegacyEncoding
 879                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 880                         {
 881                                 # Old revisions kept around in a legacy encoding?
 882                                 # Upconvert on demand.
 883                                 # ("utf8" checked for compatibility with some broken
 884                                 #  conversion scripts 2008-12-30)
 885                                 global $wgContLang;
 886                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 887                         }
 888                 }
 889                 wfProfileOut( __METHOD__ );
 890                 return $text;
 891         }
 892
 893         /**
 894          * If $wgCompressRevisions is enabled, we will compress data.
 895          * The input string is modified in place.
 896          * Return value is the flags field: contains 'gzip' if the
 897          * data is compressed, and 'utf-8' if we're saving in UTF-8
 898          * mode.
 899          *
 900          * @param $text Mixed: reference to a text
 901          * @return String
 902          */
 903         public static function compressRevisionText( &$text ) {
 904                 global $wgCompressRevisions;
 905                 $flags = array();
 906
 907                 # Revisions not marked this way will be converted
 908                 # on load if $wgLegacyCharset is set in the future.
 909                 $flags[] = 'utf-8';
 910
 911                 if( $wgCompressRevisions ) {
 912                         if( function_exists( 'gzdeflate' ) ) {
 913                                 $text = gzdeflate( $text );
 914                                 $flags[] = 'gzip';
 915                         } else {
 916                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 917                         }
 918                 }
 919                 return implode( ',', $flags );
 920         }
 921
 922         /**
 923          * Insert a new revision into the database, returning the new revision ID
 924          * number on success and dies horribly on failure.
 925          *
 926          * @param $dbw DatabaseBase: (master connection)
 927          * @return Integer
 928          */
 929         public function insertOn( $dbw ) {
 930                 global $wgDefaultExternalStore;
 931
 932                 wfProfileIn( __METHOD__ );
 933
 934                 $data = $this->mText;
 935                 $flags = Revision::compressRevisionText( $data );
 936
 937                 # Write to external storage if required
 938                 if( $wgDefaultExternalStore ) {
 939                         // Store and get the URL
 940                         $data = ExternalStore::insertToDefault( $data );
 941                         if( !$data ) {
 942                                 throw new MWException( "Unable to store text to external storage" );
 943                         }
 944                         if( $flags ) {
 945                                 $flags .= ',';
 946                         }
 947                         $flags .= 'external';
 948                 }
 949
 950                 # Record the text (or external storage URL) to the text table
 951                 if( !isset( $this->mTextId ) ) {
 952                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 953                         $dbw->insert( 'text',
 954                                 array(
 955                                         'old_id'    => $old_id,
 956                                         'old_text'  => $data,
 957                                         'old_flags' => $flags,
 958                                 ), __METHOD__
 959                         );
 960                         $this->mTextId = $dbw->insertId();
 961                 }
 962
 963                 if ( $this->mComment === null ) $this->mComment = "";
 964
 965                 # Record the edit in revisions
 966                 $rev_id = isset( $this->mId )
 967                         ? $this->mId
 968                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 969                 $dbw->insert( 'revision',
 970                         array(
 971                                 'rev_id'         => $rev_id,
 972                                 'rev_page'       => $this->mPage,
 973                                 'rev_text_id'    => $this->mTextId,
 974                                 'rev_comment'    => $this->mComment,
 975                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 976                                 'rev_user'       => $this->mUser,
 977                                 'rev_user_text'  => $this->mUserText,
 978                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 979                                 'rev_deleted'    => $this->mDeleted,
 980                                 'rev_len'        => $this->mSize,
 981                                 'rev_parent_id'  => is_null( $this->mParentId )
 982                                         ? $this->getPreviousRevisionId( $dbw )
 983                                         : $this->mParentId,
 984                                 'rev_sha1'       => is_null( $this->mSha1 )
 985                                         ? Revision::base36Sha1( $this->mText )
 986                                         : $this->mSha1
 987                         ), __METHOD__
 988                 );
 989
 990                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
 991
 992                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
 993
 994                 wfProfileOut( __METHOD__ );
 995                 return $this->mId;
 996         }
 997
 998         /**
 999          * Get the base 36 SHA-1 value for a string of text
1000          * @param $text String
1001          * @return String
1002          */
1003         public static function base36Sha1( $text ) {
1004                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1005         }
1006
1007         /**
1008          * Lazy-load the revision's text.
1009          * Currently hardcoded to the 'text' table storage engine.
1010          *
1011          * @return String
1012          */
1013         protected function loadText() {
1014                 wfProfileIn( __METHOD__ );
1015
1016                 // Caching may be beneficial for massive use of external storage
1017                 global $wgRevisionCacheExpiry, $wgMemc;
1018                 $textId = $this->getTextId();
1019                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1020                 if( $wgRevisionCacheExpiry ) {
1021                         $text = $wgMemc->get( $key );
1022                         if( is_string( $text ) ) {
1023                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1024                                 wfProfileOut( __METHOD__ );
1025                                 return $text;
1026                         }
1027                 }
1028
1029                 // If we kept data for lazy extraction, use it now...
1030                 if ( isset( $this->mTextRow ) ) {
1031                         $row = $this->mTextRow;
1032                         $this->mTextRow = null;
1033                 } else {
1034                         $row = null;
1035                 }
1036
1037                 if( !$row ) {
1038                         // Text data is immutable; check slaves first.
1039                         $dbr = wfGetDB( DB_SLAVE );
1040                         $row = $dbr->selectRow( 'text',
1041                                 array( 'old_text', 'old_flags' ),
1042                                 array( 'old_id' => $this->getTextId() ),
1043                                 __METHOD__ );
1044                 }
1045
1046                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1047                         // Possible slave lag!
1048                         $dbw = wfGetDB( DB_MASTER );
1049                         $row = $dbw->selectRow( 'text',
1050                                 array( 'old_text', 'old_flags' ),
1051                                 array( 'old_id' => $this->getTextId() ),
1052                                 __METHOD__ );
1053                 }
1054
1055                 $text = self::getRevisionText( $row );
1056
1057                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1058                 if( $wgRevisionCacheExpiry && $text !== false ) {
1059                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1060                 }
1061
1062                 wfProfileOut( __METHOD__ );
1063
1064                 return $text;
1065         }
1066
1067         /**
1068          * Create a new null-revision for insertion into a page's
1069          * history. This will not re-save the text, but simply refer
1070          * to the text from the previous version.
1071          *
1072          * Such revisions can for instance identify page rename
1073          * operations and other such meta-modifications.
1074          *
1075          * @param $dbw DatabaseBase
1076          * @param $pageId Integer: ID number of the page to read from
1077          * @param $summary String: revision's summary
1078          * @param $minor Boolean: whether the revision should be considered as minor
1079          * @return Revision|null on error
1080          */
1081         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1082                 wfProfileIn( __METHOD__ );
1083
1084                 $current = $dbw->selectRow(
1085                         array( 'page', 'revision' ),
1086                         array( 'page_latest', 'rev_text_id', 'rev_len', 'rev_sha1' ),
1087                         array(
1088                                 'page_id' => $pageId,
1089                                 'page_latest=rev_id',
1090                                 ),
1091                         __METHOD__ );
1092
1093                 if( $current ) {
1094                         $revision = new Revision( array(
1095                                 'page'       => $pageId,
1096                                 'comment'    => $summary,
1097                                 'minor_edit' => $minor,
1098                                 'text_id'    => $current->rev_text_id,
1099                                 'parent_id'  => $current->page_latest,
1100                                 'len'        => $current->rev_len,
1101                                 'sha1'       => $current->rev_sha1
1102                                 ) );
1103                 } else {
1104                         $revision = null;
1105                 }
1106
1107                 wfProfileOut( __METHOD__ );
1108                 return $revision;
1109         }
1110
1111         /**
1112          * Determine if the current user is allowed to view a particular
1113          * field of this revision, if it's marked as deleted.
1114          *
1115          * @param $field Integer:one of self::DELETED_TEXT,
1116          *                              self::DELETED_COMMENT,
1117          *                              self::DELETED_USER
1118          * @param $user User object to check, or null to use $wgUser
1119          * @return Boolean
1120          */
1121         public function userCan( $field, User $user = null ) {
1122                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1123         }
1124
1125         /**
1126          * Determine if the current user is allowed to view a particular
1127          * field of this revision, if it's marked as deleted. This is used
1128          * by various classes to avoid duplication.
1129          *
1130          * @param $bitfield Integer: current field
1131          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1132          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1133          *                               self::DELETED_USER = File::DELETED_USER
1134          * @param $user User object to check, or null to use $wgUser
1135          * @return Boolean
1136          */
1137         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1138                 if( $bitfield & $field ) { // aspect is deleted
1139                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1140                                 $permission = 'suppressrevision';
1141                         } elseif ( $field & self::DELETED_TEXT ) {
1142                                 $permission = 'deletedtext';
1143                         } else {
1144                                 $permission = 'deletedhistory';
1145                         }
1146                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1147                         if ( $user === null ) {
1148                                 global $wgUser;
1149                                 $user = $wgUser;
1150                         }
1151                         return $user->isAllowed( $permission );
1152                 } else {
1153                         return true;
1154                 }
1155         }
1156
1157         /**
1158          * Get rev_timestamp from rev_id, without loading the rest of the row
1159          *
1160          * @param $title Title
1161          * @param $id Integer
1162          * @return String
1163          */
1164         static function getTimestampFromId( $title, $id ) {
1165                 $dbr = wfGetDB( DB_SLAVE );
1166                 // Casting fix for DB2
1167                 if ( $id == '' ) {
1168                         $id = 0;
1169                 }
1170                 $conds = array( 'rev_id' => $id );
1171                 $conds['rev_page'] = $title->getArticleId();
1172                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1173                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1174                         # Not in slave, try master
1175                         $dbw = wfGetDB( DB_MASTER );
1176                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1177                 }
1178                 return wfTimestamp( TS_MW, $timestamp );
1179         }
1180
1181         /**
1182          * Get count of revisions per page...not very efficient
1183          *
1184          * @param $db DatabaseBase
1185          * @param $id Integer: page id
1186          * @return Integer
1187          */
1188         static function countByPageId( $db, $id ) {
1189                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1190                         array( 'rev_page' => $id ), __METHOD__ );
1191                 if( $row ) {
1192                         return $row->revCount;
1193                 }
1194                 return 0;
1195         }
1196
1197         /**
1198          * Get count of revisions per page...not very efficient
1199          *
1200          * @param $db DatabaseBase
1201          * @param $title Title
1202          * @return Integer
1203          */
1204         static function countByTitle( $db, $title ) {
1205                 $id = $title->getArticleId();
1206                 if( $id ) {
1207                         return Revision::countByPageId( $db, $id );
1208                 }
1209                 return 0;
1210         }
1211 }