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