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          * @since 1.19
 305          * @return Array
 306          */
 307         public static function userJoinCond() {
 308                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 309         }
 310
 311         /**
 312          * Return the value of a select() page conds array for the paeg table.
 313          * This will assure that the revision(s) are not orphaned from live pages.
 314          * @since 1.19
 315          * @return Array
 316          */
 317         public static function pageJoinCond() {
 318                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 319         }
 320
 321         /**
 322          * Return the list of revision fields that should be selected to create
 323          * a new revision.
 324          */
 325         public static function selectFields() {
 326                 return array(
 327                         'rev_id',
 328                         'rev_page',
 329                         'rev_text_id',
 330                         'rev_timestamp',
 331                         'rev_comment',
 332                         'rev_user_text',
 333                         'rev_user',
 334                         'rev_minor_edit',
 335                         'rev_deleted',
 336                         'rev_len',
 337                         'rev_parent_id',
 338                         'rev_sha1'
 339                 );
 340         }
 341
 342         /**
 343          * Return the list of text fields that should be selected to read the
 344          * revision text
 345          */
 346         public static function selectTextFields() {
 347                 return array(
 348                         'old_text',
 349                         'old_flags'
 350                 );
 351         }
 352
 353         /**
 354          * Return the list of page fields that should be selected from page table
 355          */
 356         public static function selectPageFields() {
 357                 return array(
 358                         'page_namespace',
 359                         'page_title',
 360                         'page_id',
 361                         'page_latest'
 362                 );
 363         }
 364
 365         /**
 366          * Return the list of user fields that should be selected from user table
 367          */
 368         public static function selectUserFields() {
 369                 return array( 'user_name' );
 370         }
 371
 372         /**
 373          * Constructor
 374          *
 375          * @param $row Mixed: either a database row or an array
 376          * @access private
 377          */
 378         function __construct( $row ) {
 379                 if( is_object( $row ) ) {
 380                         $this->mId        = intval( $row->rev_id );
 381                         $this->mPage      = intval( $row->rev_page );
 382                         $this->mTextId    = intval( $row->rev_text_id );
 383                         $this->mComment   =         $row->rev_comment;
 384                         $this->mUser      = intval( $row->rev_user );
 385                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 386                         $this->mTimestamp =         $row->rev_timestamp;
 387                         $this->mDeleted   = intval( $row->rev_deleted );
 388
 389                         if( !isset( $row->rev_parent_id ) ) {
 390                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 391                         } else {
 392                                 $this->mParentId  = intval( $row->rev_parent_id );
 393                         }
 394
 395                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 396                                 $this->mSize = null;
 397                         } else {
 398                                 $this->mSize = intval( $row->rev_len );
 399                         }
 400
 401                         if ( !isset( $row->rev_sha1 ) ) {
 402                                 $this->mSha1 = null;
 403                         } else {
 404                                 $this->mSha1 = $row->rev_sha1;
 405                         }
 406
 407                         if( isset( $row->page_latest ) ) {
 408                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 409                                 $this->mTitle = Title::newFromRow( $row );
 410                         } else {
 411                                 $this->mCurrent = false;
 412                                 $this->mTitle = null;
 413                         }
 414
 415                         // Lazy extraction...
 416                         $this->mText      = null;
 417                         if( isset( $row->old_text ) ) {
 418                                 $this->mTextRow = $row;
 419                         } else {
 420                                 // 'text' table row entry will be lazy-loaded
 421                                 $this->mTextRow = null;
 422                         }
 423
 424                         // Use user_name for users and rev_user_text for IPs...
 425                         $this->mUserText = null; // lazy load if left null
 426                         if ( $this->mUser == 0 ) {
 427                                 $this->mUserText = $row->rev_user_text; // IP user
 428                         } elseif ( isset( $row->user_name ) ) {
 429                                 $this->mUserText = $row->user_name; // logged-in user
 430                         }
 431                         $this->mOrigUserText = $row->rev_user_text;
 432                 } elseif( is_array( $row ) ) {
 433                         // Build a new revision to be saved...
 434                         global $wgUser; // ugh
 435
 436                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 437                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 438                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 439                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 440                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 441                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 442                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 443                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 444                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 445                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 446                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 447
 448                         // Enforce spacing trimming on supplied text
 449                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 450                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 451                         $this->mTextRow   = null;
 452
 453                         $this->mTitle     = null; # Load on demand if needed
 454                         $this->mCurrent   = false;
 455                         # If we still have no length, see it we have the text to figure it out
 456                         if ( !$this->mSize ) {
 457                                 $this->mSize = is_null( $this->mText ) ? null : strlen( $this->mText );
 458                         }
 459                         # Same for sha1
 460                         if ( $this->mSha1 === null ) {
 461                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 462                         }
 463                 } else {
 464                         throw new MWException( 'Revision constructor passed invalid row format.' );
 465                 }
 466                 $this->mUnpatrolled = null;
 467         }
 468
 469         /**
 470          * Get revision ID
 471          *
 472          * @return Integer
 473          */
 474         public function getId() {
 475                 return $this->mId;
 476         }
 477
 478         /**
 479          * Set the revision ID
 480          *
 481          * @since 1.19
 482          * @param $id Integer
 483          */
 484         public function setId( $id ) {
 485                 $this->mId = $id;
 486         }
 487
 488         /**
 489          * Get text row ID
 490          *
 491          * @return Integer
 492          */
 493         public function getTextId() {
 494                 return $this->mTextId;
 495         }
 496
 497         /**
 498          * Get parent revision ID (the original previous page revision)
 499          *
 500          * @return Integer
 501          */
 502         public function getParentId() {
 503                 return $this->mParentId;
 504         }
 505
 506         /**
 507          * Returns the length of the text in this revision, or null if unknown.
 508          *
 509          * @return Integer
 510          */
 511         public function getSize() {
 512                 return $this->mSize;
 513         }
 514
 515         /**
 516          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 517          *
 518          * @return String
 519          */
 520         public function getSha1() {
 521                 return $this->mSha1;
 522         }
 523
 524         /**
 525          * Returns the title of the page associated with this entry.
 526          *
 527          * @return Title
 528          */
 529         public function getTitle() {
 530                 if( isset( $this->mTitle ) ) {
 531                         return $this->mTitle;
 532                 }
 533                 $dbr = wfGetDB( DB_SLAVE );
 534                 $row = $dbr->selectRow(
 535                         array( 'page', 'revision' ),
 536                         self::selectPageFields(),
 537                         array( 'page_id=rev_page',
 538                                    'rev_id' => $this->mId ),
 539                         __METHOD__ );
 540                 if ( $row ) {
 541                         $this->mTitle = Title::newFromRow( $row );
 542                 }
 543                 return $this->mTitle;
 544         }
 545
 546         /**
 547          * Set the title of the revision
 548          *
 549          * @param $title Title
 550          */
 551         public function setTitle( $title ) {
 552                 $this->mTitle = $title;
 553         }
 554
 555         /**
 556          * Get the page ID
 557          *
 558          * @return Integer
 559          */
 560         public function getPage() {
 561                 return $this->mPage;
 562         }
 563
 564         /**
 565          * Fetch revision's user id if it's available to the specified audience.
 566          * If the specified audience does not have access to it, zero will be
 567          * returned.
 568          *
 569          * @param $audience Integer: one of:
 570          *      Revision::FOR_PUBLIC       to be displayed to all users
 571          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 572          *      Revision::RAW              get the ID regardless of permissions
 573          * @param $user User object to check for, only if FOR_THIS_USER is passed
 574          *              to the $audience parameter
 575          * @return Integer
 576          */
 577         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 578                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 579                         return 0;
 580                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 581                         return 0;
 582                 } else {
 583                         return $this->mUser;
 584                 }
 585         }
 586
 587         /**
 588          * Fetch revision's user id without regard for the current user's permissions
 589          *
 590          * @return String
 591          */
 592         public function getRawUser() {
 593                 return $this->mUser;
 594         }
 595
 596         /**
 597          * Fetch revision's username if it's available to the specified audience.
 598          * If the specified audience does not have access to the username, an
 599          * empty string will be returned.
 600          *
 601          * @param $audience Integer: one of:
 602          *      Revision::FOR_PUBLIC       to be displayed to all users
 603          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 604          *      Revision::RAW              get the text regardless of permissions
 605          * @param $user User object to check for, only if FOR_THIS_USER is passed
 606          *              to the $audience parameter
 607          * @return string
 608          */
 609         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 610                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 611                         return '';
 612                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 613                         return '';
 614                 } else {
 615                         return $this->getRawUserText();
 616                 }
 617         }
 618
 619         /**
 620          * Fetch revision's username without regard for view restrictions
 621          *
 622          * @return String
 623          */
 624         public function getRawUserText() {
 625                 if ( $this->mUserText === null ) {
 626                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 627                         if ( $this->mUserText === false ) {
 628                                 # This shouldn't happen, but it can if the wiki was recovered
 629                                 # via importing revs and there is no user table entry yet.
 630                                 $this->mUserText = $this->mOrigUserText;
 631                         }
 632                 }
 633                 return $this->mUserText;
 634         }
 635
 636         /**
 637          * Fetch revision comment if it's available to the specified audience.
 638          * If the specified audience does not have access to the comment, an
 639          * empty string will be returned.
 640          *
 641          * @param $audience Integer: one of:
 642          *      Revision::FOR_PUBLIC       to be displayed to all users
 643          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 644          *      Revision::RAW              get the text regardless of permissions
 645          * @param $user User object to check for, only if FOR_THIS_USER is passed
 646          *              to the $audience parameter
 647          * @return String
 648          */
 649         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 650                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 651                         return '';
 652                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 653                         return '';
 654                 } else {
 655                         return $this->mComment;
 656                 }
 657         }
 658
 659         /**
 660          * Fetch revision comment without regard for the current user's permissions
 661          *
 662          * @return String
 663          */
 664         public function getRawComment() {
 665                 return $this->mComment;
 666         }
 667
 668         /**
 669          * @return Boolean
 670          */
 671         public function isMinor() {
 672                 return (bool)$this->mMinorEdit;
 673         }
 674
 675         /**
 676          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 677          */
 678         public function isUnpatrolled() {
 679                 if( $this->mUnpatrolled !== null ) {
 680                         return $this->mUnpatrolled;
 681                 }
 682                 $dbr = wfGetDB( DB_SLAVE );
 683                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 684                         'rc_id',
 685                         array( // Add redundant user,timestamp condition so we can use the existing index
 686                                 'rc_user_text'  => $this->getRawUserText(),
 687                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 688                                 'rc_this_oldid' => $this->getId(),
 689                                 'rc_patrolled'  => 0
 690                         ),
 691                         __METHOD__
 692                 );
 693                 return (int)$this->mUnpatrolled;
 694         }
 695
 696         /**
 697          * @param $field int one of DELETED_* bitfield constants
 698          *
 699          * @return Boolean
 700          */
 701         public function isDeleted( $field ) {
 702                 return ( $this->mDeleted & $field ) == $field;
 703         }
 704
 705         /**
 706          * Get the deletion bitfield of the revision
 707          *
 708          * @return int
 709          */
 710         public function getVisibility() {
 711                 return (int)$this->mDeleted;
 712         }
 713
 714         /**
 715          * Fetch revision text if it's available to the specified audience.
 716          * If the specified audience does not have the ability to view this
 717          * revision, an empty string will be returned.
 718          *
 719          * @param $audience Integer: one of:
 720          *      Revision::FOR_PUBLIC       to be displayed to all users
 721          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 722          *      Revision::RAW              get the text regardless of permissions
 723          * @param $user User object to check for, only if FOR_THIS_USER is passed
 724          *              to the $audience parameter
 725          * @return String
 726          */
 727         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 728                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 729                         return '';
 730                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 731                         return '';
 732                 } else {
 733                         return $this->getRawText();
 734                 }
 735         }
 736
 737         /**
 738          * Alias for getText(Revision::FOR_THIS_USER)
 739          *
 740          * @deprecated since 1.17
 741          * @return String
 742          */
 743         public function revText() {
 744                 wfDeprecated( __METHOD__, '1.17' );
 745                 return $this->getText( self::FOR_THIS_USER );
 746         }
 747
 748         /**
 749          * Fetch revision text without regard for view restrictions
 750          *
 751          * @return String
 752          */
 753         public function getRawText() {
 754                 if( is_null( $this->mText ) ) {
 755                         // Revision text is immutable. Load on demand:
 756                         $this->mText = $this->loadText();
 757                 }
 758                 return $this->mText;
 759         }
 760
 761         /**
 762          * @return String
 763          */
 764         public function getTimestamp() {
 765                 return wfTimestamp( TS_MW, $this->mTimestamp );
 766         }
 767
 768         /**
 769          * @return Boolean
 770          */
 771         public function isCurrent() {
 772                 return $this->mCurrent;
 773         }
 774
 775         /**
 776          * Get previous revision for this title
 777          *
 778          * @return Revision or null
 779          */
 780         public function getPrevious() {
 781                 if( $this->getTitle() ) {
 782                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 783                         if( $prev ) {
 784                                 return Revision::newFromTitle( $this->getTitle(), $prev );
 785                         }
 786                 }
 787                 return null;
 788         }
 789
 790         /**
 791          * Get next revision for this title
 792          *
 793          * @return Revision or null
 794          */
 795         public function getNext() {
 796                 if( $this->getTitle() ) {
 797                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 798                         if ( $next ) {
 799                                 return Revision::newFromTitle( $this->getTitle(), $next );
 800                         }
 801                 }
 802                 return null;
 803         }
 804
 805         /**
 806          * Get previous revision Id for this page_id
 807          * This is used to populate rev_parent_id on save
 808          *
 809          * @param $db DatabaseBase
 810          * @return Integer
 811          */
 812         private function getPreviousRevisionId( $db ) {
 813                 if( is_null( $this->mPage ) ) {
 814                         return 0;
 815                 }
 816                 # Use page_latest if ID is not given
 817                 if( !$this->mId ) {
 818                         $prevId = $db->selectField( 'page', 'page_latest',
 819                                 array( 'page_id' => $this->mPage ),
 820                                 __METHOD__ );
 821                 } else {
 822                         $prevId = $db->selectField( 'revision', 'rev_id',
 823                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 824                                 __METHOD__,
 825                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 826                 }
 827                 return intval( $prevId );
 828         }
 829
 830         /**
 831           * Get revision text associated with an old or archive row
 832           * $row is usually an object from wfFetchRow(), both the flags and the text
 833           * field must be included
 834           *
 835           * @param $row Object: the text data
 836           * @param $prefix String: table prefix (default 'old_')
 837           * @return String: text the text requested or false on failure
 838           */
 839         public static function getRevisionText( $row, $prefix = 'old_' ) {
 840                 wfProfileIn( __METHOD__ );
 841
 842                 # Get data
 843                 $textField = $prefix . 'text';
 844                 $flagsField = $prefix . 'flags';
 845
 846                 if( isset( $row->$flagsField ) ) {
 847                         $flags = explode( ',', $row->$flagsField );
 848                 } else {
 849                         $flags = array();
 850                 }
 851
 852                 if( isset( $row->$textField ) ) {
 853                         $text = $row->$textField;
 854                 } else {
 855                         wfProfileOut( __METHOD__ );
 856                         return false;
 857                 }
 858
 859                 # Use external methods for external objects, text in table is URL-only then
 860                 if ( in_array( 'external', $flags ) ) {
 861                         $url = $text;
 862                         $parts = explode( '://', $url, 2 );
 863                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 864                                 wfProfileOut( __METHOD__ );
 865                                 return false;
 866                         }
 867                         $text = ExternalStore::fetchFromURL( $url );
 868                 }
 869
 870                 // If the text was fetched without an error, convert it
 871                 if ( $text !== false ) {
 872                         if( in_array( 'gzip', $flags ) ) {
 873                                 # Deal with optional compression of archived pages.
 874                                 # This can be done periodically via maintenance/compressOld.php, and
 875                                 # as pages are saved if $wgCompressRevisions is set.
 876                                 $text = gzinflate( $text );
 877                         }
 878
 879                         if( in_array( 'object', $flags ) ) {
 880                                 # Generic compressed storage
 881                                 $obj = unserialize( $text );
 882                                 if ( !is_object( $obj ) ) {
 883                                         // Invalid object
 884                                         wfProfileOut( __METHOD__ );
 885                                         return false;
 886                                 }
 887                                 $text = $obj->getText();
 888                         }
 889
 890                         global $wgLegacyEncoding;
 891                         if( $text !== false && $wgLegacyEncoding
 892                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 893                         {
 894                                 # Old revisions kept around in a legacy encoding?
 895                                 # Upconvert on demand.
 896                                 # ("utf8" checked for compatibility with some broken
 897                                 #  conversion scripts 2008-12-30)
 898                                 global $wgContLang;
 899                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 900                         }
 901                 }
 902                 wfProfileOut( __METHOD__ );
 903                 return $text;
 904         }
 905
 906         /**
 907          * If $wgCompressRevisions is enabled, we will compress data.
 908          * The input string is modified in place.
 909          * Return value is the flags field: contains 'gzip' if the
 910          * data is compressed, and 'utf-8' if we're saving in UTF-8
 911          * mode.
 912          *
 913          * @param $text Mixed: reference to a text
 914          * @return String
 915          */
 916         public static function compressRevisionText( &$text ) {
 917                 global $wgCompressRevisions;
 918                 $flags = array();
 919
 920                 # Revisions not marked this way will be converted
 921                 # on load if $wgLegacyCharset is set in the future.
 922                 $flags[] = 'utf-8';
 923
 924                 if( $wgCompressRevisions ) {
 925                         if( function_exists( 'gzdeflate' ) ) {
 926                                 $text = gzdeflate( $text );
 927                                 $flags[] = 'gzip';
 928                         } else {
 929                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 930                         }
 931                 }
 932                 return implode( ',', $flags );
 933         }
 934
 935         /**
 936          * Insert a new revision into the database, returning the new revision ID
 937          * number on success and dies horribly on failure.
 938          *
 939          * @param $dbw DatabaseBase: (master connection)
 940          * @return Integer
 941          */
 942         public function insertOn( $dbw ) {
 943                 global $wgDefaultExternalStore;
 944
 945                 wfProfileIn( __METHOD__ );
 946
 947                 $data = $this->mText;
 948                 $flags = Revision::compressRevisionText( $data );
 949
 950                 # Write to external storage if required
 951                 if( $wgDefaultExternalStore ) {
 952                         // Store and get the URL
 953                         $data = ExternalStore::insertToDefault( $data );
 954                         if( !$data ) {
 955                                 throw new MWException( "Unable to store text to external storage" );
 956                         }
 957                         if( $flags ) {
 958                                 $flags .= ',';
 959                         }
 960                         $flags .= 'external';
 961                 }
 962
 963                 # Record the text (or external storage URL) to the text table
 964                 if( !isset( $this->mTextId ) ) {
 965                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
 966                         $dbw->insert( 'text',
 967                                 array(
 968                                         'old_id'    => $old_id,
 969                                         'old_text'  => $data,
 970                                         'old_flags' => $flags,
 971                                 ), __METHOD__
 972                         );
 973                         $this->mTextId = $dbw->insertId();
 974                 }
 975
 976                 if ( $this->mComment === null ) $this->mComment = "";
 977
 978                 # Record the edit in revisions
 979                 $rev_id = isset( $this->mId )
 980                         ? $this->mId
 981                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
 982                 $dbw->insert( 'revision',
 983                         array(
 984                                 'rev_id'         => $rev_id,
 985                                 'rev_page'       => $this->mPage,
 986                                 'rev_text_id'    => $this->mTextId,
 987                                 'rev_comment'    => $this->mComment,
 988                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 989                                 'rev_user'       => $this->mUser,
 990                                 'rev_user_text'  => $this->mUserText,
 991                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 992                                 'rev_deleted'    => $this->mDeleted,
 993                                 'rev_len'        => $this->mSize,
 994                                 'rev_parent_id'  => is_null( $this->mParentId )
 995                                         ? $this->getPreviousRevisionId( $dbw )
 996                                         : $this->mParentId,
 997                                 'rev_sha1'       => is_null( $this->mSha1 )
 998                                         ? Revision::base36Sha1( $this->mText )
 999                                         : $this->mSha1
1000                         ), __METHOD__
1001                 );
1002
1003                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1004
1005                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1006
1007                 wfProfileOut( __METHOD__ );
1008                 return $this->mId;
1009         }
1010
1011         /**
1012          * Get the base 36 SHA-1 value for a string of text
1013          * @param $text String
1014          * @return String
1015          */
1016         public static function base36Sha1( $text ) {
1017                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1018         }
1019
1020         /**
1021          * Lazy-load the revision's text.
1022          * Currently hardcoded to the 'text' table storage engine.
1023          *
1024          * @return String
1025          */
1026         protected function loadText() {
1027                 wfProfileIn( __METHOD__ );
1028
1029                 // Caching may be beneficial for massive use of external storage
1030                 global $wgRevisionCacheExpiry, $wgMemc;
1031                 $textId = $this->getTextId();
1032                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1033                 if( $wgRevisionCacheExpiry ) {
1034                         $text = $wgMemc->get( $key );
1035                         if( is_string( $text ) ) {
1036                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1037                                 wfProfileOut( __METHOD__ );
1038                                 return $text;
1039                         }
1040                 }
1041
1042                 // If we kept data for lazy extraction, use it now...
1043                 if ( isset( $this->mTextRow ) ) {
1044                         $row = $this->mTextRow;
1045                         $this->mTextRow = null;
1046                 } else {
1047                         $row = null;
1048                 }
1049
1050                 if( !$row ) {
1051                         // Text data is immutable; check slaves first.
1052                         $dbr = wfGetDB( DB_SLAVE );
1053                         $row = $dbr->selectRow( 'text',
1054                                 array( 'old_text', 'old_flags' ),
1055                                 array( 'old_id' => $this->getTextId() ),
1056                                 __METHOD__ );
1057                 }
1058
1059                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1060                         // Possible slave lag!
1061                         $dbw = wfGetDB( DB_MASTER );
1062                         $row = $dbw->selectRow( 'text',
1063                                 array( 'old_text', 'old_flags' ),
1064                                 array( 'old_id' => $this->getTextId() ),
1065                                 __METHOD__ );
1066                 }
1067
1068                 $text = self::getRevisionText( $row );
1069
1070                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1071                 if( $wgRevisionCacheExpiry && $text !== false ) {
1072                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1073                 }
1074
1075                 wfProfileOut( __METHOD__ );
1076
1077                 return $text;
1078         }
1079
1080         /**
1081          * Create a new null-revision for insertion into a page's
1082          * history. This will not re-save the text, but simply refer
1083          * to the text from the previous version.
1084          *
1085          * Such revisions can for instance identify page rename
1086          * operations and other such meta-modifications.
1087          *
1088          * @param $dbw DatabaseBase
1089          * @param $pageId Integer: ID number of the page to read from
1090          * @param $summary String: revision's summary
1091          * @param $minor Boolean: whether the revision should be considered as minor
1092          * @return Revision|null on error
1093          */
1094         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1095                 wfProfileIn( __METHOD__ );
1096
1097                 $current = $dbw->selectRow(
1098                         array( 'page', 'revision' ),
1099                         array( 'page_latest', 'rev_text_id', 'rev_len', 'rev_sha1' ),
1100                         array(
1101                                 'page_id' => $pageId,
1102                                 'page_latest=rev_id',
1103                                 ),
1104                         __METHOD__ );
1105
1106                 if( $current ) {
1107                         $revision = new Revision( array(
1108                                 'page'       => $pageId,
1109                                 'comment'    => $summary,
1110                                 'minor_edit' => $minor,
1111                                 'text_id'    => $current->rev_text_id,
1112                                 'parent_id'  => $current->page_latest,
1113                                 'len'        => $current->rev_len,
1114                                 'sha1'       => $current->rev_sha1
1115                                 ) );
1116                 } else {
1117                         $revision = null;
1118                 }
1119
1120                 wfProfileOut( __METHOD__ );
1121                 return $revision;
1122         }
1123
1124         /**
1125          * Determine if the current user is allowed to view a particular
1126          * field of this revision, if it's marked as deleted.
1127          *
1128          * @param $field Integer:one of self::DELETED_TEXT,
1129          *                              self::DELETED_COMMENT,
1130          *                              self::DELETED_USER
1131          * @param $user User object to check, or null to use $wgUser
1132          * @return Boolean
1133          */
1134         public function userCan( $field, User $user = null ) {
1135                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1136         }
1137
1138         /**
1139          * Determine if the current user is allowed to view a particular
1140          * field of this revision, if it's marked as deleted. This is used
1141          * by various classes to avoid duplication.
1142          *
1143          * @param $bitfield Integer: current field
1144          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1145          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1146          *                               self::DELETED_USER = File::DELETED_USER
1147          * @param $user User object to check, or null to use $wgUser
1148          * @return Boolean
1149          */
1150         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1151                 if( $bitfield & $field ) { // aspect is deleted
1152                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1153                                 $permission = 'suppressrevision';
1154                         } elseif ( $field & self::DELETED_TEXT ) {
1155                                 $permission = 'deletedtext';
1156                         } else {
1157                                 $permission = 'deletedhistory';
1158                         }
1159                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1160                         if ( $user === null ) {
1161                                 global $wgUser;
1162                                 $user = $wgUser;
1163                         }
1164                         return $user->isAllowed( $permission );
1165                 } else {
1166                         return true;
1167                 }
1168         }
1169
1170         /**
1171          * Get rev_timestamp from rev_id, without loading the rest of the row
1172          *
1173          * @param $title Title
1174          * @param $id Integer
1175          * @return String
1176          */
1177         static function getTimestampFromId( $title, $id ) {
1178                 $dbr = wfGetDB( DB_SLAVE );
1179                 // Casting fix for DB2
1180                 if ( $id == '' ) {
1181                         $id = 0;
1182                 }
1183                 $conds = array( 'rev_id' => $id );
1184                 $conds['rev_page'] = $title->getArticleId();
1185                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1186                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1187                         # Not in slave, try master
1188                         $dbw = wfGetDB( DB_MASTER );
1189                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1190                 }
1191                 return wfTimestamp( TS_MW, $timestamp );
1192         }
1193
1194         /**
1195          * Get count of revisions per page...not very efficient
1196          *
1197          * @param $db DatabaseBase
1198          * @param $id Integer: page id
1199          * @return Integer
1200          */
1201         static function countByPageId( $db, $id ) {
1202                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
1203                         array( 'rev_page' => $id ), __METHOD__ );
1204                 if( $row ) {
1205                         return $row->revCount;
1206                 }
1207                 return 0;
1208         }
1209
1210         /**
1211          * Get count of revisions per page...not very efficient
1212          *
1213          * @param $db DatabaseBase
1214          * @param $title Title
1215          * @return Integer
1216          */
1217         static function countByTitle( $db, $title ) {
1218                 $id = $title->getArticleId();
1219                 if( $id ) {
1220                         return Revision::countByPageId( $db, $id );
1221                 }
1222                 return 0;
1223         }
1224 }