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
  29         /**
  30          * @var int|null
  31          */
  32         protected $mPage;
  33         protected $mUserText;
  34         protected $mOrigUserText;
  35         protected $mUser;
  36         protected $mMinorEdit;
  37         protected $mTimestamp;
  38         protected $mDeleted;
  39         protected $mSize;
  40         protected $mSha1;
  41         protected $mParentId;
  42         protected $mComment;
  43         protected $mText;
  44         protected $mTextId;
  45
  46         /**
  47          * @var stdClass|null
  48          */
  49         protected $mTextRow;
  50
  51         /**
  52          * @var null|Title
  53          */
  54         protected $mTitle;
  55         protected $mCurrent;
  56         protected $mContentModel;
  57         protected $mContentFormat;
  58
  59         /**
  60          * @var Content|null|bool
  61          */
  62         protected $mContent;
  63
  64         /**
  65          * @var null|ContentHandler
  66          */
  67         protected $mContentHandler;
  68
  69         /**
  70          * @var int
  71          */
  72         protected $mQueryFlags = 0;
  73
  74         // Revision deletion constants
  75         const DELETED_TEXT = 1;
  76         const DELETED_COMMENT = 2;
  77         const DELETED_USER = 4;
  78         const DELETED_RESTRICTED = 8;
  79         const SUPPRESSED_USER = 12; // convenience
  80
  81         // Audience options for accessors
  82         const FOR_PUBLIC = 1;
  83         const FOR_THIS_USER = 2;
  84         const RAW = 3;
  85
  86         /**
  87          * Load a page revision from a given revision ID number.
  88          * Returns null if no such revision can be found.
  89          *
  90          * $flags include:
  91          *      Revision::READ_LATEST  : Select the data from the master
  92          *      Revision::READ_LOCKING : Select & lock the data from the master
  93          *
  94          * @param int $id
  95          * @param int $flags (optional)
  96          * @return Revision|null
  97          */
  98         public static function newFromId( $id, $flags = 0 ) {
  99                 return self::newFromConds( array( 'rev_id' => intval( $id ) ), $flags );
 100         }
 101
 102         /**
 103          * Load either the current, or a specified, revision
 104          * that's attached to a given title. If not attached
 105          * to that title, will return null.
 106          *
 107          * $flags include:
 108          *      Revision::READ_LATEST  : Select the data from the master
 109          *      Revision::READ_LOCKING : Select & lock the data from the master
 110          *
 111          * @param Title $title
 112          * @param int $id (optional)
 113          * @param int $flags Bitfield (optional)
 114          * @return Revision|null
 115          */
 116         public static function newFromTitle( $title, $id = 0, $flags = 0 ) {
 117                 $conds = array(
 118                         'page_namespace' => $title->getNamespace(),
 119                         'page_title' => $title->getDBkey()
 120                 );
 121                 if ( $id ) {
 122                         // Use the specified ID
 123                         $conds['rev_id'] = $id;
 124                         // This uses slave->master fallback with READ_NORMAL. Assuming revdelete,
 125                         // moves, and merges are rare, callers can use this to reduce master queries.
 126                         return self::newFromConds( $conds, $flags );
 127                 } else {
 128                         // Use a join to get the latest revision
 129                         $conds[] = 'rev_id=page_latest';
 130                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 131                         return self::loadFromConds( $db, $conds, $flags );
 132                 }
 133         }
 134
 135         /**
 136          * Load either the current, or a specified, revision
 137          * that's attached to a given page ID.
 138          * Returns null if no such revision can be found.
 139          *
 140          * $flags include:
 141          *      Revision::READ_LATEST  : Select the data from the master (since 1.20)
 142          *      Revision::READ_LOCKING : Select & lock the data from the master
 143          *
 144          * @param int $pageId
 145          * @param int $revId (optional)
 146          * @param int $flags Bitfield (optional)
 147          * @return Revision|null
 148          */
 149         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 150                 $conds = array( 'page_id' => $pageId );
 151                 if ( $revId ) {
 152                         $conds['rev_id'] = $revId;
 153                         // This uses slave->master fallback with READ_NORMAL. Assuming revdelete
 154                         // and merges are rare, callers can use this to reduce master queries.
 155                         return self::newFromConds( $conds, $flags );
 156                 } else {
 157                         // Use a join to get the latest revision
 158                         $conds[] = 'rev_id = page_latest';
 159                         $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 160                         return self::loadFromConds( $db, $conds, $flags );
 161                 }
 162         }
 163
 164         /**
 165          * Make a fake revision object from an archive table row. This is queried
 166          * for permissions or even inserted (as in Special:Undelete)
 167          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 168          *
 169          * @param object $row
 170          * @param array $overrides
 171          *
 172          * @throws MWException
 173          * @return Revision
 174          */
 175         public static function newFromArchiveRow( $row, $overrides = array() ) {
 176                 global $wgContentHandlerUseDB;
 177
 178                 $attribs = $overrides + array(
 179                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 180                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 181                         'comment'    => $row->ar_comment,
 182                         'user'       => $row->ar_user,
 183                         'user_text'  => $row->ar_user_text,
 184                         'timestamp'  => $row->ar_timestamp,
 185                         'minor_edit' => $row->ar_minor_edit,
 186                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 187                         'deleted'    => $row->ar_deleted,
 188                         'len'        => $row->ar_len,
 189                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 190                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 191                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 192                 );
 193
 194                 if ( !$wgContentHandlerUseDB ) {
 195                         unset( $attribs['content_model'] );
 196                         unset( $attribs['content_format'] );
 197                 }
 198
 199                 if ( !isset( $attribs['title'] )
 200                         && isset( $row->ar_namespace )
 201                         && isset( $row->ar_title ) ) {
 202
 203                         $attribs['title'] = Title::makeTitle( $row->ar_namespace, $row->ar_title );
 204                 }
 205
 206                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 207                         // Pre-1.5 ar_text row
 208                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 209                         if ( $attribs['text'] === false ) {
 210                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 211                         }
 212                 }
 213                 return new self( $attribs );
 214         }
 215
 216         /**
 217          * @since 1.19
 218          *
 219          * @param object $row
 220          * @return Revision
 221          */
 222         public static function newFromRow( $row ) {
 223                 return new self( $row );
 224         }
 225
 226         /**
 227          * Load a page revision from a given revision ID number.
 228          * Returns null if no such revision can be found.
 229          *
 230          * @param DatabaseBase $db
 231          * @param int $id
 232          * @return Revision|null
 233          */
 234         public static function loadFromId( $db, $id ) {
 235                 return self::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 236         }
 237
 238         /**
 239          * Load either the current, or a specified, revision
 240          * that's attached to a given page. If not attached
 241          * to that page, will return null.
 242          *
 243          * @param DatabaseBase $db
 244          * @param int $pageid
 245          * @param int $id
 246          * @return Revision|null
 247          */
 248         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 249                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) );
 250                 if ( $id ) {
 251                         $conds['rev_id'] = intval( $id );
 252                 } else {
 253                         $conds[] = 'rev_id=page_latest';
 254                 }
 255                 return self::loadFromConds( $db, $conds );
 256         }
 257
 258         /**
 259          * Load either the current, or a specified, revision
 260          * that's attached to a given page. If not attached
 261          * to that page, will return null.
 262          *
 263          * @param DatabaseBase $db
 264          * @param Title $title
 265          * @param int $id
 266          * @return Revision|null
 267          */
 268         public static function loadFromTitle( $db, $title, $id = 0 ) {
 269                 if ( $id ) {
 270                         $matchId = intval( $id );
 271                 } else {
 272                         $matchId = 'page_latest';
 273                 }
 274                 return self::loadFromConds( $db,
 275                         array(
 276                                 "rev_id=$matchId",
 277                                 'page_namespace' => $title->getNamespace(),
 278                                 'page_title' => $title->getDBkey()
 279                         )
 280                 );
 281         }
 282
 283         /**
 284          * Load the revision for the given title with the given timestamp.
 285          * WARNING: Timestamps may in some circumstances not be unique,
 286          * so this isn't the best key to use.
 287          *
 288          * @param DatabaseBase $db
 289          * @param Title $title
 290          * @param string $timestamp
 291          * @return Revision|null
 292          */
 293         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 294                 return self::loadFromConds( $db,
 295                         array(
 296                                 'rev_timestamp' => $db->timestamp( $timestamp ),
 297                                 'page_namespace' => $title->getNamespace(),
 298                                 'page_title' => $title->getDBkey()
 299                         )
 300                 );
 301         }
 302
 303         /**
 304          * Given a set of conditions, fetch a revision.
 305          *
 306          * @param array $conditions
 307          * @param int $flags (optional)
 308          * @return Revision|null
 309          */
 310         private static function newFromConds( $conditions, $flags = 0 ) {
 311                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 312                 $rev = self::loadFromConds( $db, $conditions, $flags );
 313                 if ( $rev === null && wfGetLB()->getServerCount() > 1 ) {
 314                         if ( !( $flags & self::READ_LATEST ) ) {
 315                                 $dbw = wfGetDB( DB_MASTER );
 316                                 $rev = self::loadFromConds( $dbw, $conditions, $flags );
 317                         }
 318                 }
 319                 if ( $rev ) {
 320                         $rev->mQueryFlags = $flags;
 321                 }
 322                 return $rev;
 323         }
 324
 325         /**
 326          * Given a set of conditions, fetch a revision from
 327          * the given database connection.
 328          *
 329          * @param DatabaseBase $db
 330          * @param array $conditions
 331          * @param int $flags (optional)
 332          * @return Revision|null
 333          */
 334         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 335                 $res = self::fetchFromConds( $db, $conditions, $flags );
 336                 if ( $res ) {
 337                         $row = $res->fetchObject();
 338                         if ( $row ) {
 339                                 $ret = new Revision( $row );
 340                                 return $ret;
 341                         }
 342                 }
 343                 $ret = null;
 344                 return $ret;
 345         }
 346
 347         /**
 348          * Return a wrapper for a series of database rows to
 349          * fetch all of a given page's revisions in turn.
 350          * Each row can be fed to the constructor to get objects.
 351          *
 352          * @param Title $title
 353          * @return ResultWrapper
 354          */
 355         public static function fetchRevision( $title ) {
 356                 return self::fetchFromConds(
 357                         wfGetDB( DB_SLAVE ),
 358                         array(
 359                                 'rev_id=page_latest',
 360                                 'page_namespace' => $title->getNamespace(),
 361                                 'page_title' => $title->getDBkey()
 362                         )
 363                 );
 364         }
 365
 366         /**
 367          * Given a set of conditions, return a ResultWrapper
 368          * which will return matching database rows with the
 369          * fields necessary to build Revision objects.
 370          *
 371          * @param DatabaseBase $db
 372          * @param array $conditions
 373          * @param int $flags (optional)
 374          * @return ResultWrapper
 375          */
 376         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 377                 $fields = array_merge(
 378                         self::selectFields(),
 379                         self::selectPageFields(),
 380                         self::selectUserFields()
 381                 );
 382                 $options = array( 'LIMIT' => 1 );
 383                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 384                         $options[] = 'FOR UPDATE';
 385                 }
 386                 return $db->select(
 387                         array( 'revision', 'page', 'user' ),
 388                         $fields,
 389                         $conditions,
 390                         __METHOD__,
 391                         $options,
 392                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 393                 );
 394         }
 395
 396         /**
 397          * Return the value of a select() JOIN conds array for the user table.
 398          * This will get user table rows for logged-in users.
 399          * @since 1.19
 400          * @return array
 401          */
 402         public static function userJoinCond() {
 403                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 404         }
 405
 406         /**
 407          * Return the value of a select() page conds array for the page table.
 408          * This will assure that the revision(s) are not orphaned from live pages.
 409          * @since 1.19
 410          * @return array
 411          */
 412         public static function pageJoinCond() {
 413                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 414         }
 415
 416         /**
 417          * Return the list of revision fields that should be selected to create
 418          * a new revision.
 419          * @return array
 420          */
 421         public static function selectFields() {
 422                 global $wgContentHandlerUseDB;
 423
 424                 $fields = array(
 425                         'rev_id',
 426                         'rev_page',
 427                         'rev_text_id',
 428                         'rev_timestamp',
 429                         'rev_comment',
 430                         'rev_user_text',
 431                         'rev_user',
 432                         'rev_minor_edit',
 433                         'rev_deleted',
 434                         'rev_len',
 435                         'rev_parent_id',
 436                         'rev_sha1',
 437                 );
 438
 439                 if ( $wgContentHandlerUseDB ) {
 440                         $fields[] = 'rev_content_format';
 441                         $fields[] = 'rev_content_model';
 442                 }
 443
 444                 return $fields;
 445         }
 446
 447         /**
 448          * Return the list of revision fields that should be selected to create
 449          * a new revision from an archive row.
 450          * @return array
 451          */
 452         public static function selectArchiveFields() {
 453                 global $wgContentHandlerUseDB;
 454                 $fields = array(
 455                         'ar_id',
 456                         'ar_page_id',
 457                         'ar_rev_id',
 458                         'ar_text',
 459                         'ar_text_id',
 460                         'ar_timestamp',
 461                         'ar_comment',
 462                         'ar_user_text',
 463                         'ar_user',
 464                         'ar_minor_edit',
 465                         'ar_deleted',
 466                         'ar_len',
 467                         'ar_parent_id',
 468                         'ar_sha1',
 469                 );
 470
 471                 if ( $wgContentHandlerUseDB ) {
 472                         $fields[] = 'ar_content_format';
 473                         $fields[] = 'ar_content_model';
 474                 }
 475                 return $fields;
 476         }
 477
 478         /**
 479          * Return the list of text fields that should be selected to read the
 480          * revision text
 481          * @return array
 482          */
 483         public static function selectTextFields() {
 484                 return array(
 485                         'old_text',
 486                         'old_flags'
 487                 );
 488         }
 489
 490         /**
 491          * Return the list of page fields that should be selected from page table
 492          * @return array
 493          */
 494         public static function selectPageFields() {
 495                 return array(
 496                         'page_namespace',
 497                         'page_title',
 498                         'page_id',
 499                         'page_latest',
 500                         'page_is_redirect',
 501                         'page_len',
 502                 );
 503         }
 504
 505         /**
 506          * Return the list of user fields that should be selected from user table
 507          * @return array
 508          */
 509         public static function selectUserFields() {
 510                 return array( 'user_name' );
 511         }
 512
 513         /**
 514          * Do a batched query to get the parent revision lengths
 515          * @param DatabaseBase $db
 516          * @param array $revIds
 517          * @return array
 518          */
 519         public static function getParentLengths( $db, array $revIds ) {
 520                 $revLens = array();
 521                 if ( !$revIds ) {
 522                         return $revLens; // empty
 523                 }
 524                 $res = $db->select( 'revision',
 525                         array( 'rev_id', 'rev_len' ),
 526                         array( 'rev_id' => $revIds ),
 527                         __METHOD__ );
 528                 foreach ( $res as $row ) {
 529                         $revLens[$row->rev_id] = $row->rev_len;
 530                 }
 531                 return $revLens;
 532         }
 533
 534         /**
 535          * Constructor
 536          *
 537          * @param object|array $row Either a database row or an array
 538          * @throws MWException
 539          * @access private
 540          */
 541         function __construct( $row ) {
 542                 if ( is_object( $row ) ) {
 543                         $this->mId = intval( $row->rev_id );
 544                         $this->mPage = intval( $row->rev_page );
 545                         $this->mTextId = intval( $row->rev_text_id );
 546                         $this->mComment = $row->rev_comment;
 547                         $this->mUser = intval( $row->rev_user );
 548                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 549                         $this->mTimestamp = $row->rev_timestamp;
 550                         $this->mDeleted = intval( $row->rev_deleted );
 551
 552                         if ( !isset( $row->rev_parent_id ) ) {
 553                                 $this->mParentId = null;
 554                         } else {
 555                                 $this->mParentId = intval( $row->rev_parent_id );
 556                         }
 557
 558                         if ( !isset( $row->rev_len ) ) {
 559                                 $this->mSize = null;
 560                         } else {
 561                                 $this->mSize = intval( $row->rev_len );
 562                         }
 563
 564                         if ( !isset( $row->rev_sha1 ) ) {
 565                                 $this->mSha1 = null;
 566                         } else {
 567                                 $this->mSha1 = $row->rev_sha1;
 568                         }
 569
 570                         if ( isset( $row->page_latest ) ) {
 571                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 572                                 $this->mTitle = Title::newFromRow( $row );
 573                         } else {
 574                                 $this->mCurrent = false;
 575                                 $this->mTitle = null;
 576                         }
 577
 578                         if ( !isset( $row->rev_content_model ) ) {
 579                                 $this->mContentModel = null; # determine on demand if needed
 580                         } else {
 581                                 $this->mContentModel = strval( $row->rev_content_model );
 582                         }
 583
 584                         if ( !isset( $row->rev_content_format ) ) {
 585                                 $this->mContentFormat = null; # determine on demand if needed
 586                         } else {
 587                                 $this->mContentFormat = strval( $row->rev_content_format );
 588                         }
 589
 590                         // Lazy extraction...
 591                         $this->mText = null;
 592                         if ( isset( $row->old_text ) ) {
 593                                 $this->mTextRow = $row;
 594                         } else {
 595                                 // 'text' table row entry will be lazy-loaded
 596                                 $this->mTextRow = null;
 597                         }
 598
 599                         // Use user_name for users and rev_user_text for IPs...
 600                         $this->mUserText = null; // lazy load if left null
 601                         if ( $this->mUser == 0 ) {
 602                                 $this->mUserText = $row->rev_user_text; // IP user
 603                         } elseif ( isset( $row->user_name ) ) {
 604                                 $this->mUserText = $row->user_name; // logged-in user
 605                         }
 606                         $this->mOrigUserText = $row->rev_user_text;
 607                 } elseif ( is_array( $row ) ) {
 608                         // Build a new revision to be saved...
 609                         global $wgUser; // ugh
 610
 611                         # if we have a content object, use it to set the model and type
 612                         if ( !empty( $row['content'] ) ) {
 613                                 // @todo when is that set? test with external store setup! check out insertOn() [dk]
 614                                 if ( !empty( $row['text_id'] ) ) {
 615                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), " .
 616                                                 "can't serialize content object" );
 617                                 }
 618
 619                                 $row['content_model'] = $row['content']->getModel();
 620                                 # note: mContentFormat is initializes later accordingly
 621                                 # note: content is serialized later in this method!
 622                                 # also set text to null?
 623                         }
 624
 625                         $this->mId = isset( $row['id'] ) ? intval( $row['id'] ) : null;
 626                         $this->mPage = isset( $row['page'] ) ? intval( $row['page'] ) : null;
 627                         $this->mTextId = isset( $row['text_id'] ) ? intval( $row['text_id'] ) : null;
 628                         $this->mUserText = isset( $row['user_text'] )
 629                                 ? strval( $row['user_text'] ) : $wgUser->getName();
 630                         $this->mUser = isset( $row['user'] ) ? intval( $row['user'] ) : $wgUser->getId();
 631                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 632                         $this->mTimestamp = isset( $row['timestamp'] )
 633                                 ? strval( $row['timestamp'] ) : wfTimestampNow();
 634                         $this->mDeleted = isset( $row['deleted'] ) ? intval( $row['deleted'] ) : 0;
 635                         $this->mSize = isset( $row['len'] ) ? intval( $row['len'] ) : null;
 636                         $this->mParentId = isset( $row['parent_id'] ) ? intval( $row['parent_id'] ) : null;
 637                         $this->mSha1 = isset( $row['sha1'] ) ? strval( $row['sha1'] ) : null;
 638
 639                         $this->mContentModel = isset( $row['content_model'] )
 640                                 ? strval( $row['content_model'] ) : null;
 641                         $this->mContentFormat = isset( $row['content_format'] )
 642                                 ? strval( $row['content_format'] ) : null;
 643
 644                         // Enforce spacing trimming on supplied text
 645                         $this->mComment = isset( $row['comment'] ) ? trim( strval( $row['comment'] ) ) : null;
 646                         $this->mText = isset( $row['text'] ) ? rtrim( strval( $row['text'] ) ) : null;
 647                         $this->mTextRow = null;
 648
 649                         $this->mTitle = isset( $row['title'] ) ? $row['title'] : null;
 650
 651                         // if we have a Content object, override mText and mContentModel
 652                         if ( !empty( $row['content'] ) ) {
 653                                 if ( !( $row['content'] instanceof Content ) ) {
 654                                         throw new MWException( '`content` field must contain a Content object.' );
 655                                 }
 656
 657                                 $handler = $this->getContentHandler();
 658                                 $this->mContent = $row['content'];
 659
 660                                 $this->mContentModel = $this->mContent->getModel();
 661                                 $this->mContentHandler = null;
 662
 663                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 664                         } elseif ( $this->mText !== null ) {
 665                                 $handler = $this->getContentHandler();
 666                                 $this->mContent = $handler->unserializeContent( $this->mText );
 667                         }
 668
 669                         // If we have a Title object, make sure it is consistent with mPage.
 670                         if ( $this->mTitle && $this->mTitle->exists() ) {
 671                                 if ( $this->mPage === null ) {
 672                                         // if the page ID wasn't known, set it now
 673                                         $this->mPage = $this->mTitle->getArticleID();
 674                                 } elseif ( $this->mTitle->getArticleID() !== $this->mPage ) {
 675                                         // Got different page IDs. This may be legit (e.g. during undeletion),
 676                                         // but it seems worth mentioning it in the log.
 677                                         wfDebug( "Page ID " . $this->mPage . " mismatches the ID " .
 678                                                 $this->mTitle->getArticleID() . " provided by the Title object." );
 679                                 }
 680                         }
 681
 682                         $this->mCurrent = false;
 683
 684                         // If we still have no length, see it we have the text to figure it out
 685                         if ( !$this->mSize && $this->mContent !== null ) {
 686                                 $this->mSize = $this->mContent->getSize();
 687                         }
 688
 689                         // Same for sha1
 690                         if ( $this->mSha1 === null ) {
 691                                 $this->mSha1 = $this->mText === null ? null : self::base36Sha1( $this->mText );
 692                         }
 693
 694                         // force lazy init
 695                         $this->getContentModel();
 696                         $this->getContentFormat();
 697                 } else {
 698                         throw new MWException( 'Revision constructor passed invalid row format.' );
 699                 }
 700                 $this->mUnpatrolled = null;
 701         }
 702
 703         /**
 704          * Get revision ID
 705          *
 706          * @return int|null
 707          */
 708         public function getId() {
 709                 return $this->mId;
 710         }
 711
 712         /**
 713          * Set the revision ID
 714          *
 715          * @since 1.19
 716          * @param int $id
 717          */
 718         public function setId( $id ) {
 719                 $this->mId = $id;
 720         }
 721
 722         /**
 723          * Get text row ID
 724          *
 725          * @return int|null
 726          */
 727         public function getTextId() {
 728                 return $this->mTextId;
 729         }
 730
 731         /**
 732          * Get parent revision ID (the original previous page revision)
 733          *
 734          * @return int|null
 735          */
 736         public function getParentId() {
 737                 return $this->mParentId;
 738         }
 739
 740         /**
 741          * Returns the length of the text in this revision, or null if unknown.
 742          *
 743          * @return int|null
 744          */
 745         public function getSize() {
 746                 return $this->mSize;
 747         }
 748
 749         /**
 750          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 751          *
 752          * @return string|null
 753          */
 754         public function getSha1() {
 755                 return $this->mSha1;
 756         }
 757
 758         /**
 759          * Returns the title of the page associated with this entry or null.
 760          *
 761          * Will do a query, when title is not set and id is given.
 762          *
 763          * @return Title|null
 764          */
 765         public function getTitle() {
 766                 if ( $this->mTitle !== null ) {
 767                         return $this->mTitle;
 768                 }
 769                 //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 770                 if ( $this->mId !== null ) {
 771                         $dbr = wfGetDB( DB_SLAVE );
 772                         $row = $dbr->selectRow(
 773                                 array( 'page', 'revision' ),
 774                                 self::selectPageFields(),
 775                                 array( 'page_id=rev_page',
 776                                         'rev_id' => $this->mId ),
 777                                 __METHOD__ );
 778                         if ( $row ) {
 779                                 $this->mTitle = Title::newFromRow( $row );
 780                         }
 781                 }
 782
 783                 if ( !$this->mTitle && $this->mPage !== null && $this->mPage > 0 ) {
 784                         $this->mTitle = Title::newFromID( $this->mPage );
 785                 }
 786
 787                 return $this->mTitle;
 788         }
 789
 790         /**
 791          * Set the title of the revision
 792          *
 793          * @param Title $title
 794          */
 795         public function setTitle( $title ) {
 796                 $this->mTitle = $title;
 797         }
 798
 799         /**
 800          * Get the page ID
 801          *
 802          * @return int|null
 803          */
 804         public function getPage() {
 805                 return $this->mPage;
 806         }
 807
 808         /**
 809          * Fetch revision's user id if it's available to the specified audience.
 810          * If the specified audience does not have access to it, zero will be
 811          * returned.
 812          *
 813          * @param int $audience One of:
 814          *   Revision::FOR_PUBLIC       to be displayed to all users
 815          *   Revision::FOR_THIS_USER    to be displayed to the given user
 816          *   Revision::RAW              get the ID regardless of permissions
 817          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 818          *   to the $audience parameter
 819          * @return int
 820          */
 821         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 822                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 823                         return 0;
 824                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 825                         return 0;
 826                 } else {
 827                         return $this->mUser;
 828                 }
 829         }
 830
 831         /**
 832          * Fetch revision's user id without regard for the current user's permissions
 833          *
 834          * @return string
 835          * @deprecated since 1.25, use getUser( Revision::RAW )
 836          */
 837         public function getRawUser() {
 838                 wfDeprecated( __METHOD__, '1.25' );
 839                 return $this->getUser( self::RAW );
 840         }
 841
 842         /**
 843          * Fetch revision's username if it's available to the specified audience.
 844          * If the specified audience does not have access to the username, an
 845          * empty string will be returned.
 846          *
 847          * @param int $audience One of:
 848          *   Revision::FOR_PUBLIC       to be displayed to all users
 849          *   Revision::FOR_THIS_USER    to be displayed to the given user
 850          *   Revision::RAW              get the text regardless of permissions
 851          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 852          *   to the $audience parameter
 853          * @return string
 854          */
 855         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 856                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 857                         return '';
 858                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 859                         return '';
 860                 } else {
 861                         if ( $this->mUserText === null ) {
 862                                 $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 863                                 if ( $this->mUserText === false ) {
 864                                         # This shouldn't happen, but it can if the wiki was recovered
 865                                         # via importing revs and there is no user table entry yet.
 866                                         $this->mUserText = $this->mOrigUserText;
 867                                 }
 868                         }
 869                         return $this->mUserText;
 870                 }
 871         }
 872
 873         /**
 874          * Fetch revision's username without regard for view restrictions
 875          *
 876          * @return string
 877          * @deprecated since 1.25, use getUserText( Revision::RAW )
 878          */
 879         public function getRawUserText() {
 880                 wfDeprecated( __METHOD__, '1.25' );
 881                 return $this->getUserText( self::RAW );
 882         }
 883
 884         /**
 885          * Fetch revision comment if it's available to the specified audience.
 886          * If the specified audience does not have access to the comment, an
 887          * empty string will be returned.
 888          *
 889          * @param int $audience One of:
 890          *   Revision::FOR_PUBLIC       to be displayed to all users
 891          *   Revision::FOR_THIS_USER    to be displayed to the given user
 892          *   Revision::RAW              get the text regardless of permissions
 893          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 894          *   to the $audience parameter
 895          * @return string
 896          */
 897         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 898                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 899                         return '';
 900                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 901                         return '';
 902                 } else {
 903                         return $this->mComment;
 904                 }
 905         }
 906
 907         /**
 908          * Fetch revision comment without regard for the current user's permissions
 909          *
 910          * @return string
 911          * @deprecated since 1.25, use getComment( Revision::RAW )
 912          */
 913         public function getRawComment() {
 914                 wfDeprecated( __METHOD__, '1.25' );
 915                 return $this->getComment( self::RAW );
 916         }
 917
 918         /**
 919          * @return bool
 920          */
 921         public function isMinor() {
 922                 return (bool)$this->mMinorEdit;
 923         }
 924
 925         /**
 926          * @return int Rcid of the unpatrolled row, zero if there isn't one
 927          */
 928         public function isUnpatrolled() {
 929                 if ( $this->mUnpatrolled !== null ) {
 930                         return $this->mUnpatrolled;
 931                 }
 932                 $rc = $this->getRecentChange();
 933                 if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == 0 ) {
 934                         $this->mUnpatrolled = $rc->getAttribute( 'rc_id' );
 935                 } else {
 936                         $this->mUnpatrolled = 0;
 937                 }
 938                 return $this->mUnpatrolled;
 939         }
 940
 941         /**
 942          * Get the RC object belonging to the current revision, if there's one
 943          *
 944          * @since 1.22
 945          * @return RecentChange|null
 946          */
 947         public function getRecentChange() {
 948                 $dbr = wfGetDB( DB_SLAVE );
 949                 return RecentChange::newFromConds(
 950                         array(
 951                                 'rc_user_text' => $this->getUserText( Revision::RAW ),
 952                                 'rc_timestamp' => $dbr->timestamp( $this->getTimestamp() ),
 953                                 'rc_this_oldid' => $this->getId()
 954                         ),
 955                         __METHOD__
 956                 );
 957         }
 958
 959         /**
 960          * @param int $field One of DELETED_* bitfield constants
 961          *
 962          * @return bool
 963          */
 964         public function isDeleted( $field ) {
 965                 return ( $this->mDeleted & $field ) == $field;
 966         }
 967
 968         /**
 969          * Get the deletion bitfield of the revision
 970          *
 971          * @return int
 972          */
 973         public function getVisibility() {
 974                 return (int)$this->mDeleted;
 975         }
 976
 977         /**
 978          * Fetch revision text if it's available to the specified audience.
 979          * If the specified audience does not have the ability to view this
 980          * revision, an empty string will be returned.
 981          *
 982          * @param int $audience One of:
 983          *   Revision::FOR_PUBLIC       to be displayed to all users
 984          *   Revision::FOR_THIS_USER    to be displayed to the given user
 985          *   Revision::RAW              get the text regardless of permissions
 986          * @param User $user User object to check for, only if FOR_THIS_USER is passed
 987          *   to the $audience parameter
 988          *
 989          * @deprecated since 1.21, use getContent() instead
 990          * @todo Replace usage in core
 991          * @return string
 992          */
 993         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 994                 ContentHandler::deprecated( __METHOD__, '1.21' );
 995
 996                 $content = $this->getContent( $audience, $user );
 997                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 998         }
 999
1000         /**
1001          * Fetch revision content if it's available to the specified audience.
1002          * If the specified audience does not have the ability to view this
1003          * revision, null will be returned.
1004          *
1005          * @param int $audience One of:
1006          *   Revision::FOR_PUBLIC       to be displayed to all users
1007          *   Revision::FOR_THIS_USER    to be displayed to $wgUser
1008          *   Revision::RAW              get the text regardless of permissions
1009          * @param User $user User object to check for, only if FOR_THIS_USER is passed
1010          *   to the $audience parameter
1011          * @since 1.21
1012          * @return Content|null
1013          */
1014         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
1015                 if ( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
1016                         return null;
1017                 } elseif ( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
1018                         return null;
1019                 } else {
1020                         return $this->getContentInternal();
1021                 }
1022         }
1023
1024         /**
1025          * Fetch revision text without regard for view restrictions
1026          *
1027          * @return string
1028          *
1029          * @deprecated since 1.21. Instead, use Revision::getContent( Revision::RAW )
1030          *                         or Revision::getSerializedData() as appropriate.
1031          */
1032         public function getRawText() {
1033                 ContentHandler::deprecated( __METHOD__, "1.21" );
1034                 return $this->getText( self::RAW );
1035         }
1036
1037         /**
1038          * Fetch original serialized data without regard for view restrictions
1039          *
1040          * @since 1.21
1041          * @return string
1042          */
1043         public function getSerializedData() {
1044                 if ( $this->mText === null ) {
1045                         $this->mText = $this->loadText();
1046                 }
1047
1048                 return $this->mText;
1049         }
1050
1051         /**
1052          * Gets the content object for the revision (or null on failure).
1053          *
1054          * Note that for mutable Content objects, each call to this method will return a
1055          * fresh clone.
1056          *
1057          * @since 1.21
1058          * @return Content|null The Revision's content, or null on failure.
1059          */
1060         protected function getContentInternal() {
1061                 if ( $this->mContent === null ) {
1062                         // Revision is immutable. Load on demand:
1063                         if ( $this->mText === null ) {
1064                                 $this->mText = $this->loadText();
1065                         }
1066
1067                         if ( $this->mText !== null && $this->mText !== false ) {
1068                                 // Unserialize content
1069                                 $handler = $this->getContentHandler();
1070                                 $format = $this->getContentFormat();
1071
1072                                 $this->mContent = $handler->unserializeContent( $this->mText, $format );
1073                         }
1074                 }
1075
1076                 // NOTE: copy() will return $this for immutable content objects
1077                 return $this->mContent ? $this->mContent->copy() : null;
1078         }
1079
1080         /**
1081          * Returns the content model for this revision.
1082          *
1083          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
1084          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
1085          * is used as a last resort.
1086          *
1087          * @return string The content model id associated with this revision,
1088          *     see the CONTENT_MODEL_XXX constants.
1089          **/
1090         public function getContentModel() {
1091                 if ( !$this->mContentModel ) {
1092                         $title = $this->getTitle();
1093                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
1094
1095                         assert( !empty( $this->mContentModel ) );
1096                 }
1097
1098                 return $this->mContentModel;
1099         }
1100
1101         /**
1102          * Returns the content format for this revision.
1103          *
1104          * If no content format was stored in the database, the default format for this
1105          * revision's content model is returned.
1106          *
1107          * @return string The content format id associated with this revision,
1108          *     see the CONTENT_FORMAT_XXX constants.
1109          **/
1110         public function getContentFormat() {
1111                 if ( !$this->mContentFormat ) {
1112                         $handler = $this->getContentHandler();
1113                         $this->mContentFormat = $handler->getDefaultFormat();
1114
1115                         assert( !empty( $this->mContentFormat ) );
1116                 }
1117
1118                 return $this->mContentFormat;
1119         }
1120
1121         /**
1122          * Returns the content handler appropriate for this revision's content model.
1123          *
1124          * @throws MWException
1125          * @return ContentHandler
1126          */
1127         public function getContentHandler() {
1128                 if ( !$this->mContentHandler ) {
1129                         $model = $this->getContentModel();
1130                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1131
1132                         $format = $this->getContentFormat();
1133
1134                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1135                                 throw new MWException( "Oops, the content format $format is not supported for "
1136                                         . "this content model, $model" );
1137                         }
1138                 }
1139
1140                 return $this->mContentHandler;
1141         }
1142
1143         /**
1144          * @return string
1145          */
1146         public function getTimestamp() {
1147                 return wfTimestamp( TS_MW, $this->mTimestamp );
1148         }
1149
1150         /**
1151          * @return bool
1152          */
1153         public function isCurrent() {
1154                 return $this->mCurrent;
1155         }
1156
1157         /**
1158          * Get previous revision for this title
1159          *
1160          * @return Revision|null
1161          */
1162         public function getPrevious() {
1163                 if ( $this->getTitle() ) {
1164                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1165                         if ( $prev ) {
1166                                 return self::newFromTitle( $this->getTitle(), $prev );
1167                         }
1168                 }
1169                 return null;
1170         }
1171
1172         /**
1173          * Get next revision for this title
1174          *
1175          * @return Revision|null
1176          */
1177         public function getNext() {
1178                 if ( $this->getTitle() ) {
1179                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1180                         if ( $next ) {
1181                                 return self::newFromTitle( $this->getTitle(), $next );
1182                         }
1183                 }
1184                 return null;
1185         }
1186
1187         /**
1188          * Get previous revision Id for this page_id
1189          * This is used to populate rev_parent_id on save
1190          *
1191          * @param DatabaseBase $db
1192          * @return int
1193          */
1194         private function getPreviousRevisionId( $db ) {
1195                 if ( $this->mPage === null ) {
1196                         return 0;
1197                 }
1198                 # Use page_latest if ID is not given
1199                 if ( !$this->mId ) {
1200                         $prevId = $db->selectField( 'page', 'page_latest',
1201                                 array( 'page_id' => $this->mPage ),
1202                                 __METHOD__ );
1203                 } else {
1204                         $prevId = $db->selectField( 'revision', 'rev_id',
1205                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1206                                 __METHOD__,
1207                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1208                 }
1209                 return intval( $prevId );
1210         }
1211
1212         /**
1213          * Get revision text associated with an old or archive row
1214          * $row is usually an object from wfFetchRow(), both the flags and the text
1215          * field must be included.
1216          *
1217          * @param stdClass $row The text data
1218          * @param string $prefix Table prefix (default 'old_')
1219          * @param string|bool $wiki The name of the wiki to load the revision text from
1220          *   (same as the the wiki $row was loaded from) or false to indicate the local
1221          *   wiki (this is the default). Otherwise, it must be a symbolic wiki database
1222          *   identifier as understood by the LoadBalancer class.
1223          * @return string Text the text requested or false on failure
1224          */
1225         public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
1226
1227                 # Get data
1228                 $textField = $prefix . 'text';
1229                 $flagsField = $prefix . 'flags';
1230
1231                 if ( isset( $row->$flagsField ) ) {
1232                         $flags = explode( ',', $row->$flagsField );
1233                 } else {
1234                         $flags = array();
1235                 }
1236
1237                 if ( isset( $row->$textField ) ) {
1238                         $text = $row->$textField;
1239                 } else {
1240                         return false;
1241                 }
1242
1243                 # Use external methods for external objects, text in table is URL-only then
1244                 if ( in_array( 'external', $flags ) ) {
1245                         $url = $text;
1246                         $parts = explode( '://', $url, 2 );
1247                         if ( count( $parts ) == 1 || $parts[1] == '' ) {
1248                                 return false;
1249                         }
1250                         $text = ExternalStore::fetchFromURL( $url, array( 'wiki' => $wiki ) );
1251                 }
1252
1253                 // If the text was fetched without an error, convert it
1254                 if ( $text !== false ) {
1255                         $text = self::decompressRevisionText( $text, $flags );
1256                 }
1257                 return $text;
1258         }
1259
1260         /**
1261          * If $wgCompressRevisions is enabled, we will compress data.
1262          * The input string is modified in place.
1263          * Return value is the flags field: contains 'gzip' if the
1264          * data is compressed, and 'utf-8' if we're saving in UTF-8
1265          * mode.
1266          *
1267          * @param mixed $text Reference to a text
1268          * @return string
1269          */
1270         public static function compressRevisionText( &$text ) {
1271                 global $wgCompressRevisions;
1272                 $flags = array();
1273
1274                 # Revisions not marked this way will be converted
1275                 # on load if $wgLegacyCharset is set in the future.
1276                 $flags[] = 'utf-8';
1277
1278                 if ( $wgCompressRevisions ) {
1279                         if ( function_exists( 'gzdeflate' ) ) {
1280                                 $text = gzdeflate( $text );
1281                                 $flags[] = 'gzip';
1282                         } else {
1283                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1284                         }
1285                 }
1286                 return implode( ',', $flags );
1287         }
1288
1289         /**
1290          * Re-converts revision text according to it's flags.
1291          *
1292          * @param mixed $text Reference to a text
1293          * @param array $flags Compression flags
1294          * @return string|bool Decompressed text, or false on failure
1295          */
1296         public static function decompressRevisionText( $text, $flags ) {
1297                 if ( in_array( 'gzip', $flags ) ) {
1298                         # Deal with optional compression of archived pages.
1299                         # This can be done periodically via maintenance/compressOld.php, and
1300                         # as pages are saved if $wgCompressRevisions is set.
1301                         $text = gzinflate( $text );
1302                 }
1303
1304                 if ( in_array( 'object', $flags ) ) {
1305                         # Generic compressed storage
1306                         $obj = unserialize( $text );
1307                         if ( !is_object( $obj ) ) {
1308                                 // Invalid object
1309                                 return false;
1310                         }
1311                         $text = $obj->getText();
1312                 }
1313
1314                 global $wgLegacyEncoding;
1315                 if ( $text !== false && $wgLegacyEncoding
1316                         && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags )
1317                 ) {
1318                         # Old revisions kept around in a legacy encoding?
1319                         # Upconvert on demand.
1320                         # ("utf8" checked for compatibility with some broken
1321                         #  conversion scripts 2008-12-30)
1322                         global $wgContLang;
1323                         $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1324                 }
1325
1326                 return $text;
1327         }
1328
1329         /**
1330          * Insert a new revision into the database, returning the new revision ID
1331          * number on success and dies horribly on failure.
1332          *
1333          * @param DatabaseBase $dbw (master connection)
1334          * @throws MWException
1335          * @return int
1336          */
1337         public function insertOn( $dbw ) {
1338                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1339
1340                 $this->checkContentModel();
1341
1342                 $data = $this->mText;
1343                 $flags = self::compressRevisionText( $data );
1344
1345                 # Write to external storage if required
1346                 if ( $wgDefaultExternalStore ) {
1347                         // Store and get the URL
1348                         $data = ExternalStore::insertToDefault( $data );
1349                         if ( !$data ) {
1350                                 throw new MWException( "Unable to store text to external storage" );
1351                         }
1352                         if ( $flags ) {
1353                                 $flags .= ',';
1354                         }
1355                         $flags .= 'external';
1356                 }
1357
1358                 # Record the text (or external storage URL) to the text table
1359                 if ( $this->mTextId === null ) {
1360                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1361                         $dbw->insert( 'text',
1362                                 array(
1363                                         'old_id' => $old_id,
1364                                         'old_text' => $data,
1365                                         'old_flags' => $flags,
1366                                 ), __METHOD__
1367                         );
1368                         $this->mTextId = $dbw->insertId();
1369                 }
1370
1371                 if ( $this->mComment === null ) {
1372                         $this->mComment = "";
1373                 }
1374
1375                 # Record the edit in revisions
1376                 $rev_id = $this->mId !== null
1377                         ? $this->mId
1378                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1379                 $row = array(
1380                         'rev_id'         => $rev_id,
1381                         'rev_page'       => $this->mPage,
1382                         'rev_text_id'    => $this->mTextId,
1383                         'rev_comment'    => $this->mComment,
1384                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1385                         'rev_user'       => $this->mUser,
1386                         'rev_user_text'  => $this->mUserText,
1387                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1388                         'rev_deleted'    => $this->mDeleted,
1389                         'rev_len'        => $this->mSize,
1390                         'rev_parent_id'  => $this->mParentId === null
1391                                 ? $this->getPreviousRevisionId( $dbw )
1392                                 : $this->mParentId,
1393                         'rev_sha1'       => $this->mSha1 === null
1394                                 ? Revision::base36Sha1( $this->mText )
1395                                 : $this->mSha1,
1396                 );
1397
1398                 if ( $wgContentHandlerUseDB ) {
1399                         //NOTE: Store null for the default model and format, to save space.
1400                         //XXX: Makes the DB sensitive to changed defaults.
1401                         // Make this behavior optional? Only in miser mode?
1402
1403                         $model = $this->getContentModel();
1404                         $format = $this->getContentFormat();
1405
1406                         $title = $this->getTitle();
1407
1408                         if ( $title === null ) {
1409                                 throw new MWException( "Insufficient information to determine the title of the "
1410                                         . "revision's page!" );
1411                         }
1412
1413                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1414                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1415
1416                         $row['rev_content_model'] = ( $model === $defaultModel ) ? null : $model;
1417                         $row['rev_content_format'] = ( $format === $defaultFormat ) ? null : $format;
1418                 }
1419
1420                 $dbw->insert( 'revision', $row, __METHOD__ );
1421
1422                 $this->mId = $rev_id !== null ? $rev_id : $dbw->insertId();
1423
1424                 Hooks::run( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1425
1426                 return $this->mId;
1427         }
1428
1429         protected function checkContentModel() {
1430                 global $wgContentHandlerUseDB;
1431
1432                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1433
1434                 $model = $this->getContentModel();
1435                 $format = $this->getContentFormat();
1436                 $handler = $this->getContentHandler();
1437
1438                 if ( !$handler->isSupportedFormat( $format ) ) {
1439                         $t = $title->getPrefixedDBkey();
1440
1441                         throw new MWException( "Can't use format $format with content model $model on $t" );
1442                 }
1443
1444                 if ( !$wgContentHandlerUseDB && $title ) {
1445                         // if $wgContentHandlerUseDB is not set,
1446                         // all revisions must use the default content model and format.
1447
1448                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1449                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1450                         $defaultFormat = $defaultHandler->getDefaultFormat();
1451
1452                         if ( $this->getContentModel() != $defaultModel ) {
1453                                 $t = $title->getPrefixedDBkey();
1454
1455                                 throw new MWException( "Can't save non-default content model with "
1456                                         . "\$wgContentHandlerUseDB disabled: model is $model, "
1457                                         . "default for $t is $defaultModel" );
1458                         }
1459
1460                         if ( $this->getContentFormat() != $defaultFormat ) {
1461                                 $t = $title->getPrefixedDBkey();
1462
1463                                 throw new MWException( "Can't use non-default content format with "
1464                                         . "\$wgContentHandlerUseDB disabled: format is $format, "
1465                                         . "default for $t is $defaultFormat" );
1466                         }
1467                 }
1468
1469                 $content = $this->getContent( Revision::RAW );
1470
1471                 if ( !$content || !$content->isValid() ) {
1472                         $t = $title->getPrefixedDBkey();
1473
1474                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1475                 }
1476         }
1477
1478         /**
1479          * Get the base 36 SHA-1 value for a string of text
1480          * @param string $text
1481          * @return string
1482          */
1483         public static function base36Sha1( $text ) {
1484                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1485         }
1486
1487         /**
1488          * Lazy-load the revision's text.
1489          * Currently hardcoded to the 'text' table storage engine.
1490          *
1491          * @return string|bool The revision's text, or false on failure
1492          */
1493         protected function loadText() {
1494
1495                 // Caching may be beneficial for massive use of external storage
1496                 global $wgRevisionCacheExpiry, $wgMemc;
1497                 $textId = $this->getTextId();
1498                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1499                 if ( $wgRevisionCacheExpiry ) {
1500                         $text = $wgMemc->get( $key );
1501                         if ( is_string( $text ) ) {
1502                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1503                                 return $text;
1504                         }
1505                 }
1506
1507                 // If we kept data for lazy extraction, use it now...
1508                 if ( $this->mTextRow !== null ) {
1509                         $row = $this->mTextRow;
1510                         $this->mTextRow = null;
1511                 } else {
1512                         $row = null;
1513                 }
1514
1515                 if ( !$row ) {
1516                         // Text data is immutable; check slaves first.
1517                         $dbr = wfGetDB( DB_SLAVE );
1518                         $row = $dbr->selectRow( 'text',
1519                                 array( 'old_text', 'old_flags' ),
1520                                 array( 'old_id' => $textId ),
1521                                 __METHOD__ );
1522                 }
1523
1524                 // Fallback to the master in case of slave lag. Also use FOR UPDATE if it was
1525                 // used to fetch this revision to avoid missing the row due to REPEATABLE-READ.
1526                 $forUpdate = ( $this->mQueryFlags & self::READ_LOCKING == self::READ_LOCKING );
1527                 if ( !$row && ( $forUpdate || wfGetLB()->getServerCount() > 1 ) ) {
1528                         $dbw = wfGetDB( DB_MASTER );
1529                         $row = $dbw->selectRow( 'text',
1530                                 array( 'old_text', 'old_flags' ),
1531                                 array( 'old_id' => $textId ),
1532                                 __METHOD__,
1533                                 $forUpdate ? array( 'FOR UPDATE' ) : array() );
1534                 }
1535
1536                 if ( !$row ) {
1537                         wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );
1538                 }
1539
1540                 $text = self::getRevisionText( $row );
1541                 if ( $row && $text === false ) {
1542                         wfDebugLog( 'Revision', "No blob for text row '$textId' (revision {$this->getId()})." );
1543                 }
1544
1545                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1546                 if ( $wgRevisionCacheExpiry && $text !== false ) {
1547                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1548                 }
1549
1550                 return $text;
1551         }
1552
1553         /**
1554          * Create a new null-revision for insertion into a page's
1555          * history. This will not re-save the text, but simply refer
1556          * to the text from the previous version.
1557          *
1558          * Such revisions can for instance identify page rename
1559          * operations and other such meta-modifications.
1560          *
1561          * @param DatabaseBase $dbw
1562          * @param int $pageId ID number of the page to read from
1563          * @param string $summary Revision's summary
1564          * @param bool $minor Whether the revision should be considered as minor
1565          * @param User|null $user User object to use or null for $wgUser
1566          * @return Revision|null Revision or null on error
1567          */
1568         public static function newNullRevision( $dbw, $pageId, $summary, $minor, $user = null ) {
1569                 global $wgContentHandlerUseDB;
1570
1571                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1572                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1573
1574                 if ( $wgContentHandlerUseDB ) {
1575                         $fields[] = 'rev_content_model';
1576                         $fields[] = 'rev_content_format';
1577                 }
1578
1579                 $current = $dbw->selectRow(
1580                         array( 'page', 'revision' ),
1581                         $fields,
1582                         array(
1583                                 'page_id' => $pageId,
1584                                 'page_latest=rev_id',
1585                                 ),
1586                         __METHOD__ );
1587
1588                 if ( $current ) {
1589                         if ( !$user ) {
1590                                 global $wgUser;
1591                                 $user = $wgUser;
1592                         }
1593
1594                         $row = array(
1595                                 'page'       => $pageId,
1596                                 'user_text'  => $user->getName(),
1597                                 'user'       => $user->getId(),
1598                                 'comment'    => $summary,
1599                                 'minor_edit' => $minor,
1600                                 'text_id'    => $current->rev_text_id,
1601                                 'parent_id'  => $current->page_latest,
1602                                 'len'        => $current->rev_len,
1603                                 'sha1'       => $current->rev_sha1
1604                         );
1605
1606                         if ( $wgContentHandlerUseDB ) {
1607                                 $row['content_model'] = $current->rev_content_model;
1608                                 $row['content_format'] = $current->rev_content_format;
1609                         }
1610
1611                         $revision = new Revision( $row );
1612                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1613                 } else {
1614                         $revision = null;
1615                 }
1616
1617                 return $revision;
1618         }
1619
1620         /**
1621          * Determine if the current user is allowed to view a particular
1622          * field of this revision, if it's marked as deleted.
1623          *
1624          * @param int $field One of self::DELETED_TEXT,
1625          *                              self::DELETED_COMMENT,
1626          *                              self::DELETED_USER
1627          * @param User|null $user User object to check, or null to use $wgUser
1628          * @return bool
1629          */
1630         public function userCan( $field, User $user = null ) {
1631                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1632         }
1633
1634         /**
1635          * Determine if the current user is allowed to view a particular
1636          * field of this revision, if it's marked as deleted. This is used
1637          * by various classes to avoid duplication.
1638          *
1639          * @param int $bitfield Current field
1640          * @param int $field One of self::DELETED_TEXT = File::DELETED_FILE,
1641          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1642          *                               self::DELETED_USER = File::DELETED_USER
1643          * @param User|null $user User object to check, or null to use $wgUser
1644          * @param Title|null $title A Title object to check for per-page restrictions on,
1645          *                          instead of just plain userrights
1646          * @return bool
1647          */
1648         public static function userCanBitfield( $bitfield, $field, User $user = null,
1649                 Title $title = null
1650         ) {
1651                 if ( $bitfield & $field ) { // aspect is deleted
1652                         if ( $user === null ) {
1653                                 global $wgUser;
1654                                 $user = $wgUser;
1655                         }
1656                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1657                                 $permissions = array( 'suppressrevision', 'viewsuppressed' );
1658                         } elseif ( $field & self::DELETED_TEXT ) {
1659                                 $permissions = array( 'deletedtext' );
1660                         } else {
1661                                 $permissions = array( 'deletedhistory' );
1662                         }
1663                         $permissionlist = implode( ', ', $permissions );
1664                         if ( $title === null ) {
1665                                 wfDebug( "Checking for $permissionlist due to $field match on $bitfield\n" );
1666                                 return call_user_func_array( array( $user, 'isAllowedAny' ), $permissions );
1667                         } else {
1668                                 $text = $title->getPrefixedText();
1669                                 wfDebug( "Checking for $permissionlist on $text due to $field match on $bitfield\n" );
1670                                 foreach ( $permissions as $perm ) {
1671                                         if ( $title->userCan( $perm, $user ) ) {
1672                                                 return true;
1673                                         }
1674                                 }
1675                                 return false;
1676                         }
1677                 } else {
1678                         return true;
1679                 }
1680         }
1681
1682         /**
1683          * Get rev_timestamp from rev_id, without loading the rest of the row
1684          *
1685          * @param Title $title
1686          * @param int $id
1687          * @return string
1688          */
1689         static function getTimestampFromId( $title, $id ) {
1690                 $dbr = wfGetDB( DB_SLAVE );
1691                 // Casting fix for databases that can't take '' for rev_id
1692                 if ( $id == '' ) {
1693                         $id = 0;
1694                 }
1695                 $conds = array( 'rev_id' => $id );
1696                 $conds['rev_page'] = $title->getArticleID();
1697                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1698                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1699                         # Not in slave, try master
1700                         $dbw = wfGetDB( DB_MASTER );
1701                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1702                 }
1703                 return wfTimestamp( TS_MW, $timestamp );
1704         }
1705
1706         /**
1707          * Get count of revisions per page...not very efficient
1708          *
1709          * @param DatabaseBase $db
1710          * @param int $id Page id
1711          * @return int
1712          */
1713         static function countByPageId( $db, $id ) {
1714                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1715                         array( 'rev_page' => $id ), __METHOD__ );
1716                 if ( $row ) {
1717                         return $row->revCount;
1718                 }
1719                 return 0;
1720         }
1721
1722         /**
1723          * Get count of revisions per page...not very efficient
1724          *
1725          * @param DatabaseBase $db
1726          * @param Title $title
1727          * @return int
1728          */
1729         static function countByTitle( $db, $title ) {
1730                 $id = $title->getArticleID();
1731                 if ( $id ) {
1732                         return self::countByPageId( $db, $id );
1733                 }
1734                 return 0;
1735         }
1736
1737         /**
1738          * Check if no edits were made by other users since
1739          * the time a user started editing the page. Limit to
1740          * 50 revisions for the sake of performance.
1741          *
1742          * @since 1.20
1743          * @deprecated since 1.24
1744          *
1745          * @param DatabaseBase|int $db The Database to perform the check on. May be given as a
1746          *        Database object or a database identifier usable with wfGetDB.
1747          * @param int $pageId The ID of the page in question
1748          * @param int $userId The ID of the user in question
1749          * @param string $since Look at edits since this time
1750          *
1751          * @return bool True if the given user was the only one to edit since the given timestamp
1752          */
1753         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1754                 if ( !$userId ) {
1755                         return false;
1756                 }
1757
1758                 if ( is_int( $db ) ) {
1759                         $db = wfGetDB( $db );
1760                 }
1761
1762                 $res = $db->select( 'revision',
1763                         'rev_user',
1764                         array(
1765                                 'rev_page' => $pageId,
1766                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1767                         ),
1768                         __METHOD__,
1769                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1770                 foreach ( $res as $row ) {
1771                         if ( $row->rev_user != $userId ) {
1772                                 return false;
1773                         }
1774                 }
1775                 return true;
1776         }
1777 }