includes/Revision.php

   1 <?php
   2 /**
   3  * Representation of a page version.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * @todo document
  25  */
  26 class Revision implements IDBAccessObject {
  27         protected $mId;
  28         protected $mPage;
  29         protected $mUserText;
  30         protected $mOrigUserText;
  31         protected $mUser;
  32         protected $mMinorEdit;
  33         protected $mTimestamp;
  34         protected $mDeleted;
  35         protected $mSize;
  36         protected $mSha1;
  37         protected $mParentId;
  38         protected $mComment;
  39         protected $mText;
  40         protected $mTextRow;
  41         protected $mTitle;
  42         protected $mCurrent;
  43
  44         // Revision deletion constants
  45         const DELETED_TEXT = 1;
  46         const DELETED_COMMENT = 2;
  47         const DELETED_USER = 4;
  48         const DELETED_RESTRICTED = 8;
  49         const SUPPRESSED_USER = 12; // convenience
  50
  51         // Audience options for accessors
  52         const FOR_PUBLIC = 1;
  53         const FOR_THIS_USER = 2;
  54         const RAW = 3;
  55
  56         /**
  57          * Load a page revision from a given revision ID number.
  58          * Returns null if no such revision can be found.
  59          *
  60          * $flags include:
  61          *      Revision::READ_LATEST  : Select the data from the master
  62          *      Revision::READ_LOCKING : Select & lock the data from the master
  63          *
  64          * @param $id Integer
  65          * @param $flags Integer (optional)
  66          * @return Revision or null
  67          */
  68         public static function newFromId( $id, $flags = 0 ) {
  69                 return self::newFromConds( array( 'rev_id' => intval( $id ) ), $flags );
  70         }
  71
  72         /**
  73          * Load either the current, or a specified, revision
  74          * that's attached to a given title. If not attached
  75          * to that title, will return null.
  76          *
  77          * $flags include:
  78          *      Revision::READ_LATEST  : Select the data from the master
  79          *      Revision::READ_LOCKING : Select & lock the data from the master
  80          *
  81          * @param $title Title
  82          * @param $id Integer (optional)
  83          * @param $flags Integer Bitfield (optional)
  84          * @return Revision or null
  85          */
  86         public static function newFromTitle( $title, $id = 0, $flags = null ) {
  87                 $conds = array(
  88                         'page_namespace' => $title->getNamespace(),
  89                         'page_title'     => $title->getDBkey()
  90                 );
  91                 if ( $id ) {
  92                         // Use the specified ID
  93                         $conds['rev_id'] = $id;
  94                 } else {
  95                         // Use a join to get the latest revision
  96                         $conds[] = 'rev_id=page_latest';
  97                         // Callers assume this will be up-to-date
  98                         $flags = is_int( $flags ) ? $flags : self::READ_LATEST; // b/c
  99                 }
 100                 return self::newFromConds( $conds, (int)$flags );
 101         }
 102
 103         /**
 104          * Load either the current, or a specified, revision
 105          * that's attached to a given page ID.
 106          * Returns null if no such revision can be found.
 107          *
 108          * $flags include:
 109          *      Revision::READ_LATEST  : Select the data from the master
 110          *      Revision::READ_LOCKING : Select & lock the data from the master
 111          *
 112          * @param $revId Integer
 113          * @param $pageId Integer (optional)
 114          * @param $flags Integer Bitfield (optional)
 115          * @return Revision or null
 116          */
 117         public static function newFromPageId( $pageId, $revId = 0, $flags = null ) {
 118                 $conds = array( 'page_id' => $pageId );
 119                 if ( $revId ) {
 120                         $conds['rev_id'] = $revId;
 121                 } else {
 122                         // Use a join to get the latest revision
 123                         $conds[] = 'rev_id = page_latest';
 124                         // Callers assume this will be up-to-date
 125                         $flags = is_int( $flags ) ? $flags : self::READ_LATEST; // b/c
 126                 }
 127                 return self::newFromConds( $conds, (int)$flags );
 128         }
 129
 130         /**
 131          * Make a fake revision object from an archive table row. This is queried
 132          * for permissions or even inserted (as in Special:Undelete)
 133          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 134          *
 135          * @param $row
 136          * @param $overrides array
 137          *
 138          * @return Revision
 139          */
 140         public static function newFromArchiveRow( $row, $overrides = array() ) {
 141                 $attribs = $overrides + array(
 142                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 143                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 144                         'comment'    => $row->ar_comment,
 145                         'user'       => $row->ar_user,
 146                         'user_text'  => $row->ar_user_text,
 147                         'timestamp'  => $row->ar_timestamp,
 148                         'minor_edit' => $row->ar_minor_edit,
 149                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 150                         'deleted'    => $row->ar_deleted,
 151                         'len'        => $row->ar_len,
 152                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 153                 );
 154                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 155                         // Pre-1.5 ar_text row
 156                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 157                         if ( $attribs['text'] === false ) {
 158                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 159                         }
 160                 }
 161                 return new self( $attribs );
 162         }
 163
 164         /**
 165          * @since 1.19
 166          *
 167          * @param $row
 168          * @return Revision
 169          */
 170         public static function newFromRow( $row ) {
 171                 return new self( $row );
 172         }
 173
 174         /**
 175          * Load a page revision from a given revision ID number.
 176          * Returns null if no such revision can be found.
 177          *
 178          * @param $db DatabaseBase
 179          * @param $id Integer
 180          * @return Revision or null
 181          */
 182         public static function loadFromId( $db, $id ) {
 183                 return self::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 184         }
 185
 186         /**
 187          * Load either the current, or a specified, revision
 188          * that's attached to a given page. If not attached
 189          * to that page, will return null.
 190          *
 191          * @param $db DatabaseBase
 192          * @param $pageid Integer
 193          * @param $id Integer
 194          * @return Revision or null
 195          */
 196         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 197                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 198                 if( $id ) {
 199                         $conds['rev_id'] = intval( $id );
 200                 } else {
 201                         $conds[] = 'rev_id=page_latest';
 202                 }
 203                 return self::loadFromConds( $db, $conds );
 204         }
 205
 206         /**
 207          * Load either the current, or a specified, revision
 208          * that's attached to a given page. If not attached
 209          * to that page, will return null.
 210          *
 211          * @param $db DatabaseBase
 212          * @param $title Title
 213          * @param $id Integer
 214          * @return Revision or null
 215          */
 216         public static function loadFromTitle( $db, $title, $id = 0 ) {
 217                 if( $id ) {
 218                         $matchId = intval( $id );
 219                 } else {
 220                         $matchId = 'page_latest';
 221                 }
 222                 return self::loadFromConds( $db,
 223                         array( "rev_id=$matchId",
 224                                    'page_namespace' => $title->getNamespace(),
 225                                    'page_title'     => $title->getDBkey() )
 226                 );
 227         }
 228
 229         /**
 230          * Load the revision for the given title with the given timestamp.
 231          * WARNING: Timestamps may in some circumstances not be unique,
 232          * so this isn't the best key to use.
 233          *
 234          * @param $db DatabaseBase
 235          * @param $title Title
 236          * @param $timestamp String
 237          * @return Revision or null
 238          */
 239         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 240                 return self::loadFromConds( $db,
 241                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 242                                    'page_namespace' => $title->getNamespace(),
 243                                    'page_title'     => $title->getDBkey() )
 244                 );
 245         }
 246
 247         /**
 248          * Given a set of conditions, fetch a revision.
 249          *
 250          * @param $conditions Array
 251          * @param $flags integer (optional)
 252          * @return Revision or null
 253          */
 254         private static function newFromConds( $conditions, $flags = 0 ) {
 255                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 256                 $rev = self::loadFromConds( $db, $conditions, $flags );
 257                 if ( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 258                         if ( !( $flags & self::READ_LATEST ) ) {
 259                                 $dbw = wfGetDB( DB_MASTER );
 260                                 $rev = self::loadFromConds( $dbw, $conditions, $flags );
 261                         }
 262                 }
 263                 return $rev;
 264         }
 265
 266         /**
 267          * Given a set of conditions, fetch a revision from
 268          * the given database connection.
 269          *
 270          * @param $db DatabaseBase
 271          * @param $conditions Array
 272          * @param $flags integer (optional)
 273          * @return Revision or null
 274          */
 275         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 276                 $res = self::fetchFromConds( $db, $conditions, $flags );
 277                 if( $res ) {
 278                         $row = $res->fetchObject();
 279                         if( $row ) {
 280                                 $ret = new Revision( $row );
 281                                 return $ret;
 282                         }
 283                 }
 284                 $ret = null;
 285                 return $ret;
 286         }
 287
 288         /**
 289          * Return a wrapper for a series of database rows to
 290          * fetch all of a given page's revisions in turn.
 291          * Each row can be fed to the constructor to get objects.
 292          *
 293          * @param $title Title
 294          * @return ResultWrapper
 295          */
 296         public static function fetchRevision( $title ) {
 297                 return self::fetchFromConds(
 298                         wfGetDB( DB_SLAVE ),
 299                         array( 'rev_id=page_latest',
 300                                    'page_namespace' => $title->getNamespace(),
 301                                    'page_title'     => $title->getDBkey() )
 302                 );
 303         }
 304
 305         /**
 306          * Given a set of conditions, return a ResultWrapper
 307          * which will return matching database rows with the
 308          * fields necessary to build Revision objects.
 309          *
 310          * @param $db DatabaseBase
 311          * @param $conditions Array
 312          * @param $flags integer (optional)
 313          * @return ResultWrapper
 314          */
 315         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 316                 $fields = array_merge(
 317                         self::selectFields(),
 318                         self::selectPageFields(),
 319                         self::selectUserFields()
 320                 );
 321                 $options = array( 'LIMIT' => 1 );
 322                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 323                         $options[] = 'FOR UPDATE';
 324                 }
 325                 return $db->select(
 326                         array( 'revision', 'page', 'user' ),
 327                         $fields,
 328                         $conditions,
 329                         __METHOD__,
 330                         $options,
 331                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 332                 );
 333         }
 334
 335         /**
 336          * Return the value of a select() JOIN conds array for the user table.
 337          * This will get user table rows for logged-in users.
 338          * @since 1.19
 339          * @return Array
 340          */
 341         public static function userJoinCond() {
 342                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 343         }
 344
 345         /**
 346          * Return the value of a select() page conds array for the paeg table.
 347          * This will assure that the revision(s) are not orphaned from live pages.
 348          * @since 1.19
 349          * @return Array
 350          */
 351         public static function pageJoinCond() {
 352                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 353         }
 354
 355         /**
 356          * Return the list of revision fields that should be selected to create
 357          * a new revision.
 358          * @return array
 359          */
 360         public static function selectFields() {
 361                 return array(
 362                         'rev_id',
 363                         'rev_page',
 364                         'rev_text_id',
 365                         'rev_timestamp',
 366                         'rev_comment',
 367                         'rev_user_text',
 368                         'rev_user',
 369                         'rev_minor_edit',
 370                         'rev_deleted',
 371                         'rev_len',
 372                         'rev_parent_id',
 373                         'rev_sha1'
 374                 );
 375         }
 376
 377         /**
 378          * Return the list of text fields that should be selected to read the
 379          * revision text
 380          * @return array
 381          */
 382         public static function selectTextFields() {
 383                 return array(
 384                         'old_text',
 385                         'old_flags'
 386                 );
 387         }
 388
 389         /**
 390          * Return the list of page fields that should be selected from page table
 391          * @return array
 392          */
 393         public static function selectPageFields() {
 394                 return array(
 395                         'page_namespace',
 396                         'page_title',
 397                         'page_id',
 398                         'page_latest',
 399                         'page_is_redirect',
 400                         'page_len',
 401                 );
 402         }
 403
 404         /**
 405          * Return the list of user fields that should be selected from user table
 406          * @return array
 407          */
 408         public static function selectUserFields() {
 409                 return array( 'user_name' );
 410         }
 411
 412         /**
 413          * Do a batched query to get the parent revision lengths
 414          * @param $db DatabaseBase
 415          * @param $revIds Array
 416          * @return array
 417          */
 418         public static function getParentLengths( $db, array $revIds ) {
 419                 $revLens = array();
 420                 if ( !$revIds ) {
 421                         return $revLens; // empty
 422                 }
 423                 wfProfileIn( __METHOD__ );
 424                 $res = $db->select( 'revision',
 425                         array( 'rev_id', 'rev_len' ),
 426                         array( 'rev_id' => $revIds ),
 427                         __METHOD__ );
 428                 foreach ( $res as $row ) {
 429                         $revLens[$row->rev_id] = $row->rev_len;
 430                 }
 431                 wfProfileOut( __METHOD__ );
 432                 return $revLens;
 433         }
 434
 435         /**
 436          * Constructor
 437          *
 438          * @param $row Mixed: either a database row or an array
 439          * @access private
 440          */
 441         function __construct( $row ) {
 442                 if( is_object( $row ) ) {
 443                         $this->mId        = intval( $row->rev_id );
 444                         $this->mPage      = intval( $row->rev_page );
 445                         $this->mTextId    = intval( $row->rev_text_id );
 446                         $this->mComment   =         $row->rev_comment;
 447                         $this->mUser      = intval( $row->rev_user );
 448                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 449                         $this->mTimestamp =         $row->rev_timestamp;
 450                         $this->mDeleted   = intval( $row->rev_deleted );
 451
 452                         if( !isset( $row->rev_parent_id ) ) {
 453                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 454                         } else {
 455                                 $this->mParentId  = intval( $row->rev_parent_id );
 456                         }
 457
 458                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 459                                 $this->mSize = null;
 460                         } else {
 461                                 $this->mSize = intval( $row->rev_len );
 462                         }
 463
 464                         if ( !isset( $row->rev_sha1 ) ) {
 465                                 $this->mSha1 = null;
 466                         } else {
 467                                 $this->mSha1 = $row->rev_sha1;
 468                         }
 469
 470                         if( isset( $row->page_latest ) ) {
 471                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 472                                 $this->mTitle = Title::newFromRow( $row );
 473                         } else {
 474                                 $this->mCurrent = false;
 475                                 $this->mTitle = null;
 476                         }
 477
 478                         // Lazy extraction...
 479                         $this->mText      = null;
 480                         if( isset( $row->old_text ) ) {
 481                                 $this->mTextRow = $row;
 482                         } else {
 483                                 // 'text' table row entry will be lazy-loaded
 484                                 $this->mTextRow = null;
 485                         }
 486
 487                         // Use user_name for users and rev_user_text for IPs...
 488                         $this->mUserText = null; // lazy load if left null
 489                         if ( $this->mUser == 0 ) {
 490                                 $this->mUserText = $row->rev_user_text; // IP user
 491                         } elseif ( isset( $row->user_name ) ) {
 492                                 $this->mUserText = $row->user_name; // logged-in user
 493                         }
 494                         $this->mOrigUserText = $row->rev_user_text;
 495                 } elseif( is_array( $row ) ) {
 496                         // Build a new revision to be saved...
 497                         global $wgUser; // ugh
 498
 499                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 500                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 501                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 502                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 503                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 504                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 505                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 506                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 507                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 508                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 509                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 510
 511                         // Enforce spacing trimming on supplied text
 512                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 513                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 514                         $this->mTextRow   = null;
 515
 516                         $this->mTitle     = null; # Load on demand if needed
 517                         $this->mCurrent   = false;
 518                         # If we still have no length, see it we have the text to figure it out
 519                         if ( !$this->mSize ) {
 520                                 $this->mSize = is_null( $this->mText ) ? null : strlen( $this->mText );
 521                         }
 522                         # Same for sha1
 523                         if ( $this->mSha1 === null ) {
 524                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 525                         }
 526                 } else {
 527                         throw new MWException( 'Revision constructor passed invalid row format.' );
 528                 }
 529                 $this->mUnpatrolled = null;
 530         }
 531
 532         /**
 533          * Get revision ID
 534          *
 535          * @return Integer|null
 536          */
 537         public function getId() {
 538                 return $this->mId;
 539         }
 540
 541         /**
 542          * Set the revision ID
 543          *
 544          * @since 1.19
 545          * @param $id Integer
 546          */
 547         public function setId( $id ) {
 548                 $this->mId = $id;
 549         }
 550
 551         /**
 552          * Get text row ID
 553          *
 554          * @return Integer|null
 555          */
 556         public function getTextId() {
 557                 return $this->mTextId;
 558         }
 559
 560         /**
 561          * Get parent revision ID (the original previous page revision)
 562          *
 563          * @return Integer|null
 564          */
 565         public function getParentId() {
 566                 return $this->mParentId;
 567         }
 568
 569         /**
 570          * Returns the length of the text in this revision, or null if unknown.
 571          *
 572          * @return Integer|null
 573          */
 574         public function getSize() {
 575                 return $this->mSize;
 576         }
 577
 578         /**
 579          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 580          *
 581          * @return String|null
 582          */
 583         public function getSha1() {
 584                 return $this->mSha1;
 585         }
 586
 587         /**
 588          * Returns the title of the page associated with this entry or null.
 589          *
 590          * Will do a query, when title is not set and id is given.
 591          *
 592          * @return Title|null
 593          */
 594         public function getTitle() {
 595                 if( isset( $this->mTitle ) ) {
 596                         return $this->mTitle;
 597                 }
 598                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL
 599                         $dbr = wfGetDB( DB_SLAVE );
 600                         $row = $dbr->selectRow(
 601                                 array( 'page', 'revision' ),
 602                                 self::selectPageFields(),
 603                                 array( 'page_id=rev_page',
 604                                            'rev_id' => $this->mId ),
 605                                 __METHOD__ );
 606                         if ( $row ) {
 607                                 $this->mTitle = Title::newFromRow( $row );
 608                         }
 609                 }
 610                 return $this->mTitle;
 611         }
 612
 613         /**
 614          * Set the title of the revision
 615          *
 616          * @param $title Title
 617          */
 618         public function setTitle( $title ) {
 619                 $this->mTitle = $title;
 620         }
 621
 622         /**
 623          * Get the page ID
 624          *
 625          * @return Integer|null
 626          */
 627         public function getPage() {
 628                 return $this->mPage;
 629         }
 630
 631         /**
 632          * Fetch revision's user id if it's available to the specified audience.
 633          * If the specified audience does not have access to it, zero will be
 634          * returned.
 635          *
 636          * @param $audience Integer: one of:
 637          *      Revision::FOR_PUBLIC       to be displayed to all users
 638          *      Revision::FOR_THIS_USER    to be displayed to the given user
 639          *      Revision::RAW              get the ID regardless of permissions
 640          * @param $user User object to check for, only if FOR_THIS_USER is passed
 641          *              to the $audience parameter
 642          * @return Integer
 643          */
 644         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 645                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 646                         return 0;
 647                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 648                         return 0;
 649                 } else {
 650                         return $this->mUser;
 651                 }
 652         }
 653
 654         /**
 655          * Fetch revision's user id without regard for the current user's permissions
 656          *
 657          * @return String
 658          */
 659         public function getRawUser() {
 660                 return $this->mUser;
 661         }
 662
 663         /**
 664          * Fetch revision's username if it's available to the specified audience.
 665          * If the specified audience does not have access to the username, an
 666          * empty string will be returned.
 667          *
 668          * @param $audience Integer: one of:
 669          *      Revision::FOR_PUBLIC       to be displayed to all users
 670          *      Revision::FOR_THIS_USER    to be displayed to the given user
 671          *      Revision::RAW              get the text regardless of permissions
 672          * @param $user User object to check for, only if FOR_THIS_USER is passed
 673          *              to the $audience parameter
 674          * @return string
 675          */
 676         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 677                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 678                         return '';
 679                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 680                         return '';
 681                 } else {
 682                         return $this->getRawUserText();
 683                 }
 684         }
 685
 686         /**
 687          * Fetch revision's username without regard for view restrictions
 688          *
 689          * @return String
 690          */
 691         public function getRawUserText() {
 692                 if ( $this->mUserText === null ) {
 693                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 694                         if ( $this->mUserText === false ) {
 695                                 # This shouldn't happen, but it can if the wiki was recovered
 696                                 # via importing revs and there is no user table entry yet.
 697                                 $this->mUserText = $this->mOrigUserText;
 698                         }
 699                 }
 700                 return $this->mUserText;
 701         }
 702
 703         /**
 704          * Fetch revision comment if it's available to the specified audience.
 705          * If the specified audience does not have access to the comment, an
 706          * empty string will be returned.
 707          *
 708          * @param $audience Integer: one of:
 709          *      Revision::FOR_PUBLIC       to be displayed to all users
 710          *      Revision::FOR_THIS_USER    to be displayed to the given user
 711          *      Revision::RAW              get the text regardless of permissions
 712          * @param $user User object to check for, only if FOR_THIS_USER is passed
 713          *              to the $audience parameter
 714          * @return String
 715          */
 716         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 717                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 718                         return '';
 719                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 720                         return '';
 721                 } else {
 722                         return $this->mComment;
 723                 }
 724         }
 725
 726         /**
 727          * Fetch revision comment without regard for the current user's permissions
 728          *
 729          * @return String
 730          */
 731         public function getRawComment() {
 732                 return $this->mComment;
 733         }
 734
 735         /**
 736          * @return Boolean
 737          */
 738         public function isMinor() {
 739                 return (bool)$this->mMinorEdit;
 740         }
 741
 742         /**
 743          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 744          */
 745         public function isUnpatrolled() {
 746                 if( $this->mUnpatrolled !== null ) {
 747                         return $this->mUnpatrolled;
 748                 }
 749                 $dbr = wfGetDB( DB_SLAVE );
 750                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 751                         'rc_id',
 752                         array( // Add redundant user,timestamp condition so we can use the existing index
 753                                 'rc_user_text'  => $this->getRawUserText(),
 754                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 755                                 'rc_this_oldid' => $this->getId(),
 756                                 'rc_patrolled'  => 0
 757                         ),
 758                         __METHOD__
 759                 );
 760                 return (int)$this->mUnpatrolled;
 761         }
 762
 763         /**
 764          * @param $field int one of DELETED_* bitfield constants
 765          *
 766          * @return Boolean
 767          */
 768         public function isDeleted( $field ) {
 769                 return ( $this->mDeleted & $field ) == $field;
 770         }
 771
 772         /**
 773          * Get the deletion bitfield of the revision
 774          *
 775          * @return int
 776          */
 777         public function getVisibility() {
 778                 return (int)$this->mDeleted;
 779         }
 780
 781         /**
 782          * Fetch revision text if it's available to the specified audience.
 783          * If the specified audience does not have the ability to view this
 784          * revision, an empty string will be returned.
 785          *
 786          * @param $audience Integer: one of:
 787          *      Revision::FOR_PUBLIC       to be displayed to all users
 788          *      Revision::FOR_THIS_USER    to be displayed to the given user
 789          *      Revision::RAW              get the text regardless of permissions
 790          * @param $user User object to check for, only if FOR_THIS_USER is passed
 791          *              to the $audience parameter
 792          * @return String
 793          */
 794         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 795                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 796                         return '';
 797                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 798                         return '';
 799                 } else {
 800                         return $this->getRawText();
 801                 }
 802         }
 803
 804         /**
 805          * Alias for getText(Revision::FOR_THIS_USER)
 806          *
 807          * @deprecated since 1.17
 808          * @return String
 809          */
 810         public function revText() {
 811                 wfDeprecated( __METHOD__, '1.17' );
 812                 return $this->getText( self::FOR_THIS_USER );
 813         }
 814
 815         /**
 816          * Fetch revision text without regard for view restrictions
 817          *
 818          * @return String
 819          */
 820         public function getRawText() {
 821                 if( is_null( $this->mText ) ) {
 822                         // Revision text is immutable. Load on demand:
 823                         $this->mText = $this->loadText();
 824                 }
 825                 return $this->mText;
 826         }
 827
 828         /**
 829          * @return String
 830          */
 831         public function getTimestamp() {
 832                 return wfTimestamp( TS_MW, $this->mTimestamp );
 833         }
 834
 835         /**
 836          * @return Boolean
 837          */
 838         public function isCurrent() {
 839                 return $this->mCurrent;
 840         }
 841
 842         /**
 843          * Get previous revision for this title
 844          *
 845          * @return Revision or null
 846          */
 847         public function getPrevious() {
 848                 if( $this->getTitle() ) {
 849                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
 850                         if( $prev ) {
 851                                 return self::newFromTitle( $this->getTitle(), $prev );
 852                         }
 853                 }
 854                 return null;
 855         }
 856
 857         /**
 858          * Get next revision for this title
 859          *
 860          * @return Revision or null
 861          */
 862         public function getNext() {
 863                 if( $this->getTitle() ) {
 864                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
 865                         if ( $next ) {
 866                                 return self::newFromTitle( $this->getTitle(), $next );
 867                         }
 868                 }
 869                 return null;
 870         }
 871
 872         /**
 873          * Get previous revision Id for this page_id
 874          * This is used to populate rev_parent_id on save
 875          *
 876          * @param $db DatabaseBase
 877          * @return Integer
 878          */
 879         private function getPreviousRevisionId( $db ) {
 880                 if( is_null( $this->mPage ) ) {
 881                         return 0;
 882                 }
 883                 # Use page_latest if ID is not given
 884                 if( !$this->mId ) {
 885                         $prevId = $db->selectField( 'page', 'page_latest',
 886                                 array( 'page_id' => $this->mPage ),
 887                                 __METHOD__ );
 888                 } else {
 889                         $prevId = $db->selectField( 'revision', 'rev_id',
 890                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
 891                                 __METHOD__,
 892                                 array( 'ORDER BY' => 'rev_id DESC' ) );
 893                 }
 894                 return intval( $prevId );
 895         }
 896
 897         /**
 898           * Get revision text associated with an old or archive row
 899           * $row is usually an object from wfFetchRow(), both the flags and the text
 900           * field must be included
 901           *
 902           * @param $row Object: the text data
 903           * @param $prefix String: table prefix (default 'old_')
 904           * @return String: text the text requested or false on failure
 905           */
 906         public static function getRevisionText( $row, $prefix = 'old_' ) {
 907                 wfProfileIn( __METHOD__ );
 908
 909                 # Get data
 910                 $textField = $prefix . 'text';
 911                 $flagsField = $prefix . 'flags';
 912
 913                 if( isset( $row->$flagsField ) ) {
 914                         $flags = explode( ',', $row->$flagsField );
 915                 } else {
 916                         $flags = array();
 917                 }
 918
 919                 if( isset( $row->$textField ) ) {
 920                         $text = $row->$textField;
 921                 } else {
 922                         wfProfileOut( __METHOD__ );
 923                         return false;
 924                 }
 925
 926                 # Use external methods for external objects, text in table is URL-only then
 927                 if ( in_array( 'external', $flags ) ) {
 928                         $url = $text;
 929                         $parts = explode( '://', $url, 2 );
 930                         if( count( $parts ) == 1 || $parts[1] == '' ) {
 931                                 wfProfileOut( __METHOD__ );
 932                                 return false;
 933                         }
 934                         $text = ExternalStore::fetchFromURL( $url );
 935                 }
 936
 937                 // If the text was fetched without an error, convert it
 938                 if ( $text !== false ) {
 939                         if( in_array( 'gzip', $flags ) ) {
 940                                 # Deal with optional compression of archived pages.
 941                                 # This can be done periodically via maintenance/compressOld.php, and
 942                                 # as pages are saved if $wgCompressRevisions is set.
 943                                 $text = gzinflate( $text );
 944                         }
 945
 946                         if( in_array( 'object', $flags ) ) {
 947                                 # Generic compressed storage
 948                                 $obj = unserialize( $text );
 949                                 if ( !is_object( $obj ) ) {
 950                                         // Invalid object
 951                                         wfProfileOut( __METHOD__ );
 952                                         return false;
 953                                 }
 954                                 $text = $obj->getText();
 955                         }
 956
 957                         global $wgLegacyEncoding;
 958                         if( $text !== false && $wgLegacyEncoding
 959                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
 960                         {
 961                                 # Old revisions kept around in a legacy encoding?
 962                                 # Upconvert on demand.
 963                                 # ("utf8" checked for compatibility with some broken
 964                                 #  conversion scripts 2008-12-30)
 965                                 global $wgContLang;
 966                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
 967                         }
 968                 }
 969                 wfProfileOut( __METHOD__ );
 970                 return $text;
 971         }
 972
 973         /**
 974          * If $wgCompressRevisions is enabled, we will compress data.
 975          * The input string is modified in place.
 976          * Return value is the flags field: contains 'gzip' if the
 977          * data is compressed, and 'utf-8' if we're saving in UTF-8
 978          * mode.
 979          *
 980          * @param $text Mixed: reference to a text
 981          * @return String
 982          */
 983         public static function compressRevisionText( &$text ) {
 984                 global $wgCompressRevisions;
 985                 $flags = array();
 986
 987                 # Revisions not marked this way will be converted
 988                 # on load if $wgLegacyCharset is set in the future.
 989                 $flags[] = 'utf-8';
 990
 991                 if( $wgCompressRevisions ) {
 992                         if( function_exists( 'gzdeflate' ) ) {
 993                                 $text = gzdeflate( $text );
 994                                 $flags[] = 'gzip';
 995                         } else {
 996                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
 997                         }
 998                 }
 999                 return implode( ',', $flags );
1000         }
1001
1002         /**
1003          * Insert a new revision into the database, returning the new revision ID
1004          * number on success and dies horribly on failure.
1005          *
1006          * @param $dbw DatabaseBase: (master connection)
1007          * @return Integer
1008          */
1009         public function insertOn( $dbw ) {
1010                 global $wgDefaultExternalStore;
1011
1012                 wfProfileIn( __METHOD__ );
1013
1014                 $data = $this->mText;
1015                 $flags = self::compressRevisionText( $data );
1016
1017                 # Write to external storage if required
1018                 if( $wgDefaultExternalStore ) {
1019                         // Store and get the URL
1020                         $data = ExternalStore::insertToDefault( $data );
1021                         if( !$data ) {
1022                                 throw new MWException( "Unable to store text to external storage" );
1023                         }
1024                         if( $flags ) {
1025                                 $flags .= ',';
1026                         }
1027                         $flags .= 'external';
1028                 }
1029
1030                 # Record the text (or external storage URL) to the text table
1031                 if( !isset( $this->mTextId ) ) {
1032                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1033                         $dbw->insert( 'text',
1034                                 array(
1035                                         'old_id'    => $old_id,
1036                                         'old_text'  => $data,
1037                                         'old_flags' => $flags,
1038                                 ), __METHOD__
1039                         );
1040                         $this->mTextId = $dbw->insertId();
1041                 }
1042
1043                 if ( $this->mComment === null ) $this->mComment = "";
1044
1045                 # Record the edit in revisions
1046                 $rev_id = isset( $this->mId )
1047                         ? $this->mId
1048                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1049                 $dbw->insert( 'revision',
1050                         array(
1051                                 'rev_id'         => $rev_id,
1052                                 'rev_page'       => $this->mPage,
1053                                 'rev_text_id'    => $this->mTextId,
1054                                 'rev_comment'    => $this->mComment,
1055                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1056                                 'rev_user'       => $this->mUser,
1057                                 'rev_user_text'  => $this->mUserText,
1058                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1059                                 'rev_deleted'    => $this->mDeleted,
1060                                 'rev_len'        => $this->mSize,
1061                                 'rev_parent_id'  => is_null( $this->mParentId )
1062                                         ? $this->getPreviousRevisionId( $dbw )
1063                                         : $this->mParentId,
1064                                 'rev_sha1'       => is_null( $this->mSha1 )
1065                                         ? self::base36Sha1( $this->mText )
1066                                         : $this->mSha1
1067                         ), __METHOD__
1068                 );
1069
1070                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1071
1072                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1073
1074                 wfProfileOut( __METHOD__ );
1075                 return $this->mId;
1076         }
1077
1078         /**
1079          * Get the base 36 SHA-1 value for a string of text
1080          * @param $text String
1081          * @return String
1082          */
1083         public static function base36Sha1( $text ) {
1084                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1085         }
1086
1087         /**
1088          * Lazy-load the revision's text.
1089          * Currently hardcoded to the 'text' table storage engine.
1090          *
1091          * @return String
1092          */
1093         protected function loadText() {
1094                 wfProfileIn( __METHOD__ );
1095
1096                 // Caching may be beneficial for massive use of external storage
1097                 global $wgRevisionCacheExpiry, $wgMemc;
1098                 $textId = $this->getTextId();
1099                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1100                 if( $wgRevisionCacheExpiry ) {
1101                         $text = $wgMemc->get( $key );
1102                         if( is_string( $text ) ) {
1103                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1104                                 wfProfileOut( __METHOD__ );
1105                                 return $text;
1106                         }
1107                 }
1108
1109                 // If we kept data for lazy extraction, use it now...
1110                 if ( isset( $this->mTextRow ) ) {
1111                         $row = $this->mTextRow;
1112                         $this->mTextRow = null;
1113                 } else {
1114                         $row = null;
1115                 }
1116
1117                 if( !$row ) {
1118                         // Text data is immutable; check slaves first.
1119                         $dbr = wfGetDB( DB_SLAVE );
1120                         $row = $dbr->selectRow( 'text',
1121                                 array( 'old_text', 'old_flags' ),
1122                                 array( 'old_id' => $this->getTextId() ),
1123                                 __METHOD__ );
1124                 }
1125
1126                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1127                         // Possible slave lag!
1128                         $dbw = wfGetDB( DB_MASTER );
1129                         $row = $dbw->selectRow( 'text',
1130                                 array( 'old_text', 'old_flags' ),
1131                                 array( 'old_id' => $this->getTextId() ),
1132                                 __METHOD__ );
1133                 }
1134
1135                 $text = self::getRevisionText( $row );
1136
1137                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1138                 if( $wgRevisionCacheExpiry && $text !== false ) {
1139                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1140                 }
1141
1142                 wfProfileOut( __METHOD__ );
1143
1144                 return $text;
1145         }
1146
1147         /**
1148          * Create a new null-revision for insertion into a page's
1149          * history. This will not re-save the text, but simply refer
1150          * to the text from the previous version.
1151          *
1152          * Such revisions can for instance identify page rename
1153          * operations and other such meta-modifications.
1154          *
1155          * @param $dbw DatabaseBase
1156          * @param $pageId Integer: ID number of the page to read from
1157          * @param $summary String: revision's summary
1158          * @param $minor Boolean: whether the revision should be considered as minor
1159          * @return Revision|null on error
1160          */
1161         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1162                 wfProfileIn( __METHOD__ );
1163
1164                 $current = $dbw->selectRow(
1165                         array( 'page', 'revision' ),
1166                         array( 'page_latest', 'page_namespace', 'page_title',
1167                                 'rev_text_id', 'rev_len', 'rev_sha1' ),
1168                         array(
1169                                 'page_id' => $pageId,
1170                                 'page_latest=rev_id',
1171                                 ),
1172                         __METHOD__ );
1173
1174                 if( $current ) {
1175                         $revision = new Revision( array(
1176                                 'page'       => $pageId,
1177                                 'comment'    => $summary,
1178                                 'minor_edit' => $minor,
1179                                 'text_id'    => $current->rev_text_id,
1180                                 'parent_id'  => $current->page_latest,
1181                                 'len'        => $current->rev_len,
1182                                 'sha1'       => $current->rev_sha1
1183                                 ) );
1184                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1185                 } else {
1186                         $revision = null;
1187                 }
1188
1189                 wfProfileOut( __METHOD__ );
1190                 return $revision;
1191         }
1192
1193         /**
1194          * Determine if the current user is allowed to view a particular
1195          * field of this revision, if it's marked as deleted.
1196          *
1197          * @param $field Integer:one of self::DELETED_TEXT,
1198          *                              self::DELETED_COMMENT,
1199          *                              self::DELETED_USER
1200          * @param $user User object to check, or null to use $wgUser
1201          * @return Boolean
1202          */
1203         public function userCan( $field, User $user = null ) {
1204                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1205         }
1206
1207         /**
1208          * Determine if the current user is allowed to view a particular
1209          * field of this revision, if it's marked as deleted. This is used
1210          * by various classes to avoid duplication.
1211          *
1212          * @param $bitfield Integer: current field
1213          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1214          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1215          *                               self::DELETED_USER = File::DELETED_USER
1216          * @param $user User object to check, or null to use $wgUser
1217          * @return Boolean
1218          */
1219         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1220                 if( $bitfield & $field ) { // aspect is deleted
1221                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1222                                 $permission = 'suppressrevision';
1223                         } elseif ( $field & self::DELETED_TEXT ) {
1224                                 $permission = 'deletedtext';
1225                         } else {
1226                                 $permission = 'deletedhistory';
1227                         }
1228                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1229                         if ( $user === null ) {
1230                                 global $wgUser;
1231                                 $user = $wgUser;
1232                         }
1233                         return $user->isAllowed( $permission );
1234                 } else {
1235                         return true;
1236                 }
1237         }
1238
1239         /**
1240          * Get rev_timestamp from rev_id, without loading the rest of the row
1241          *
1242          * @param $title Title
1243          * @param $id Integer
1244          * @return String
1245          */
1246         static function getTimestampFromId( $title, $id ) {
1247                 $dbr = wfGetDB( DB_SLAVE );
1248                 // Casting fix for DB2
1249                 if ( $id == '' ) {
1250                         $id = 0;
1251                 }
1252                 $conds = array( 'rev_id' => $id );
1253                 $conds['rev_page'] = $title->getArticleID();
1254                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1255                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1256                         # Not in slave, try master
1257                         $dbw = wfGetDB( DB_MASTER );
1258                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1259                 }
1260                 return wfTimestamp( TS_MW, $timestamp );
1261         }
1262
1263         /**
1264          * Get count of revisions per page...not very efficient
1265          *
1266          * @param $db DatabaseBase
1267          * @param $id Integer: page id
1268          * @return Integer
1269          */
1270         static function countByPageId( $db, $id ) {
1271                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1272                         array( 'rev_page' => $id ), __METHOD__ );
1273                 if( $row ) {
1274                         return $row->revCount;
1275                 }
1276                 return 0;
1277         }
1278
1279         /**
1280          * Get count of revisions per page...not very efficient
1281          *
1282          * @param $db DatabaseBase
1283          * @param $title Title
1284          * @return Integer
1285          */
1286         static function countByTitle( $db, $title ) {
1287                 $id = $title->getArticleID();
1288                 if( $id ) {
1289                         return self::countByPageId( $db, $id );
1290                 }
1291                 return 0;
1292         }
1293
1294         /**
1295          * Check if no edits were made by other users since
1296          * the time a user started editing the page. Limit to
1297          * 50 revisions for the sake of performance.
1298          *
1299          * @since 1.20
1300          *
1301          * @param DatabaseBase|int $db the Database to perform the check on. May be given as a Database object or
1302          *        a database identifier usable with wfGetDB.
1303          * @param int $pageId the ID of the page in question
1304          * @param int $userId the ID of the user in question
1305          * @param string $since look at edits since this time
1306          *
1307          * @return bool True if the given user was the only one to edit since the given timestamp
1308          */
1309         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1310                 if ( !$userId ) return false;
1311
1312                 if ( is_int( $db ) ) {
1313                         $db = wfGetDB( $db );
1314                 }
1315
1316                 $res = $db->select( 'revision',
1317                         'rev_user',
1318                         array(
1319                                 'rev_page' => $pageId,
1320                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1321                         ),
1322                         __METHOD__,
1323                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1324                 foreach ( $res as $row ) {
1325                         if ( $row->rev_user != $userId ) {
1326                                 return false;
1327                         }
1328                 }
1329                 return true;
1330         }
1331 }