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         protected $mContentModel;
  44         protected $mContentFormat;
  45         protected $mContent;
  46         protected $mContentHandler;
  47
  48         // Revision deletion constants
  49         const DELETED_TEXT = 1;
  50         const DELETED_COMMENT = 2;
  51         const DELETED_USER = 4;
  52         const DELETED_RESTRICTED = 8;
  53         const SUPPRESSED_USER = 12; // convenience
  54
  55         // Audience options for accessors
  56         const FOR_PUBLIC = 1;
  57         const FOR_THIS_USER = 2;
  58         const RAW = 3;
  59
  60         /**
  61          * Load a page revision from a given revision ID number.
  62          * Returns null if no such revision can be found.
  63          *
  64          * $flags include:
  65          *      Revision::READ_LATEST  : Select the data from the master
  66          *      Revision::READ_LOCKING : Select & lock the data from the master
  67          *
  68          * @param $id Integer
  69          * @param $flags Integer (optional)
  70          * @return Revision or null
  71          */
  72         public static function newFromId( $id, $flags = 0 ) {
  73                 return self::newFromConds( array( 'rev_id' => intval( $id ) ), $flags );
  74         }
  75
  76         /**
  77          * Load either the current, or a specified, revision
  78          * that's attached to a given title. If not attached
  79          * to that title, will return null.
  80          *
  81          * $flags include:
  82          *      Revision::READ_LATEST  : Select the data from the master
  83          *      Revision::READ_LOCKING : Select & lock the data from the master
  84          *
  85          * @param $title Title
  86          * @param $id Integer (optional)
  87          * @param $flags Integer Bitfield (optional)
  88          * @return Revision or null
  89          */
  90         public static function newFromTitle( $title, $id = 0, $flags = null ) {
  91                 $conds = array(
  92                         'page_namespace' => $title->getNamespace(),
  93                         'page_title'     => $title->getDBkey()
  94                 );
  95                 if ( $id ) {
  96                         // Use the specified ID
  97                         $conds['rev_id'] = $id;
  98                 } else {
  99                         // Use a join to get the latest revision
 100                         $conds[] = 'rev_id=page_latest';
 101                         // Callers assume this will be up-to-date
 102                         $flags = is_int( $flags ) ? $flags : self::READ_LATEST; // b/c
 103                 }
 104                 return self::newFromConds( $conds, (int)$flags );
 105         }
 106
 107         /**
 108          * Load either the current, or a specified, revision
 109          * that's attached to a given page ID.
 110          * Returns null if no such revision can be found.
 111          *
 112          * $flags include:
 113          *      Revision::READ_LATEST  : Select the data from the master
 114          *      Revision::READ_LOCKING : Select & lock the data from the master
 115          *
 116          * @param $revId Integer
 117          * @param $pageId Integer (optional)
 118          * @param $flags Integer Bitfield (optional)
 119          * @return Revision or null
 120          */
 121         public static function newFromPageId( $pageId, $revId = 0, $flags = 0 ) {
 122                 $conds = array( 'page_id' => $pageId );
 123                 if ( $revId ) {
 124                         $conds['rev_id'] = $revId;
 125                 } else {
 126                         // Use a join to get the latest revision
 127                         $conds[] = 'rev_id = page_latest';
 128                 }
 129                 return self::newFromConds( $conds, (int)$flags );
 130         }
 131
 132         /**
 133          * Make a fake revision object from an archive table row. This is queried
 134          * for permissions or even inserted (as in Special:Undelete)
 135          * @todo FIXME: Should be a subclass for RevisionDelete. [TS]
 136          *
 137          * @param $row
 138          * @param $overrides array
 139          *
 140          * @throws MWException
 141          * @return Revision
 142          */
 143         public static function newFromArchiveRow( $row, $overrides = array() ) {
 144                 global $wgContentHandlerUseDB;
 145
 146                 $attribs = $overrides + array(
 147                         'page'       => isset( $row->ar_page_id ) ? $row->ar_page_id : null,
 148                         'id'         => isset( $row->ar_rev_id ) ? $row->ar_rev_id : null,
 149                         'comment'    => $row->ar_comment,
 150                         'user'       => $row->ar_user,
 151                         'user_text'  => $row->ar_user_text,
 152                         'timestamp'  => $row->ar_timestamp,
 153                         'minor_edit' => $row->ar_minor_edit,
 154                         'text_id'    => isset( $row->ar_text_id ) ? $row->ar_text_id : null,
 155                         'deleted'    => $row->ar_deleted,
 156                         'len'        => $row->ar_len,
 157                         'sha1'       => isset( $row->ar_sha1 ) ? $row->ar_sha1 : null,
 158                         'content_model'   => isset( $row->ar_content_model ) ? $row->ar_content_model : null,
 159                         'content_format'  => isset( $row->ar_content_format ) ? $row->ar_content_format : null,
 160                 );
 161
 162                 if ( !$wgContentHandlerUseDB ) {
 163                         unset( $attribs['content_model'] );
 164                         unset( $attribs['content_format'] );
 165                 }
 166
 167                 if ( isset( $row->ar_text ) && !$row->ar_text_id ) {
 168                         // Pre-1.5 ar_text row
 169                         $attribs['text'] = self::getRevisionText( $row, 'ar_' );
 170                         if ( $attribs['text'] === false ) {
 171                                 throw new MWException( 'Unable to load text from archive row (possibly bug 22624)' );
 172                         }
 173                 }
 174                 return new self( $attribs );
 175         }
 176
 177         /**
 178          * @since 1.19
 179          *
 180          * @param $row
 181          * @return Revision
 182          */
 183         public static function newFromRow( $row ) {
 184                 return new self( $row );
 185         }
 186
 187         /**
 188          * Load a page revision from a given revision ID number.
 189          * Returns null if no such revision can be found.
 190          *
 191          * @param $db DatabaseBase
 192          * @param $id Integer
 193          * @return Revision or null
 194          */
 195         public static function loadFromId( $db, $id ) {
 196                 return self::loadFromConds( $db, array( 'rev_id' => intval( $id ) ) );
 197         }
 198
 199         /**
 200          * Load either the current, or a specified, revision
 201          * that's attached to a given page. If not attached
 202          * to that page, will return null.
 203          *
 204          * @param $db DatabaseBase
 205          * @param $pageid Integer
 206          * @param $id Integer
 207          * @return Revision or null
 208          */
 209         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
 210                 $conds = array( 'rev_page' => intval( $pageid ), 'page_id'  => intval( $pageid ) );
 211                 if( $id ) {
 212                         $conds['rev_id'] = intval( $id );
 213                 } else {
 214                         $conds[] = 'rev_id=page_latest';
 215                 }
 216                 return self::loadFromConds( $db, $conds );
 217         }
 218
 219         /**
 220          * Load either the current, or a specified, revision
 221          * that's attached to a given page. If not attached
 222          * to that page, will return null.
 223          *
 224          * @param $db DatabaseBase
 225          * @param $title Title
 226          * @param $id Integer
 227          * @return Revision or null
 228          */
 229         public static function loadFromTitle( $db, $title, $id = 0 ) {
 230                 if( $id ) {
 231                         $matchId = intval( $id );
 232                 } else {
 233                         $matchId = 'page_latest';
 234                 }
 235                 return self::loadFromConds( $db,
 236                         array( "rev_id=$matchId",
 237                                    'page_namespace' => $title->getNamespace(),
 238                                    'page_title'     => $title->getDBkey() )
 239                 );
 240         }
 241
 242         /**
 243          * Load the revision for the given title with the given timestamp.
 244          * WARNING: Timestamps may in some circumstances not be unique,
 245          * so this isn't the best key to use.
 246          *
 247          * @param $db DatabaseBase
 248          * @param $title Title
 249          * @param $timestamp String
 250          * @return Revision or null
 251          */
 252         public static function loadFromTimestamp( $db, $title, $timestamp ) {
 253                 return self::loadFromConds( $db,
 254                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 255                                    'page_namespace' => $title->getNamespace(),
 256                                    'page_title'     => $title->getDBkey() )
 257                 );
 258         }
 259
 260         /**
 261          * Given a set of conditions, fetch a revision.
 262          *
 263          * @param $conditions Array
 264          * @param $flags integer (optional)
 265          * @return Revision or null
 266          */
 267         private static function newFromConds( $conditions, $flags = 0 ) {
 268                 $db = wfGetDB( ( $flags & self::READ_LATEST ) ? DB_MASTER : DB_SLAVE );
 269                 $rev = self::loadFromConds( $db, $conditions, $flags );
 270                 if ( is_null( $rev ) && wfGetLB()->getServerCount() > 1 ) {
 271                         if ( !( $flags & self::READ_LATEST ) ) {
 272                                 $dbw = wfGetDB( DB_MASTER );
 273                                 $rev = self::loadFromConds( $dbw, $conditions, $flags );
 274                         }
 275                 }
 276                 return $rev;
 277         }
 278
 279         /**
 280          * Given a set of conditions, fetch a revision from
 281          * the given database connection.
 282          *
 283          * @param $db DatabaseBase
 284          * @param $conditions Array
 285          * @param $flags integer (optional)
 286          * @return Revision or null
 287          */
 288         private static function loadFromConds( $db, $conditions, $flags = 0 ) {
 289                 $res = self::fetchFromConds( $db, $conditions, $flags );
 290                 if( $res ) {
 291                         $row = $res->fetchObject();
 292                         if( $row ) {
 293                                 $ret = new Revision( $row );
 294                                 return $ret;
 295                         }
 296                 }
 297                 $ret = null;
 298                 return $ret;
 299         }
 300
 301         /**
 302          * Return a wrapper for a series of database rows to
 303          * fetch all of a given page's revisions in turn.
 304          * Each row can be fed to the constructor to get objects.
 305          *
 306          * @param $title Title
 307          * @return ResultWrapper
 308          */
 309         public static function fetchRevision( $title ) {
 310                 return self::fetchFromConds(
 311                         wfGetDB( DB_SLAVE ),
 312                         array( 'rev_id=page_latest',
 313                                    'page_namespace' => $title->getNamespace(),
 314                                    'page_title'     => $title->getDBkey() )
 315                 );
 316         }
 317
 318         /**
 319          * Given a set of conditions, return a ResultWrapper
 320          * which will return matching database rows with the
 321          * fields necessary to build Revision objects.
 322          *
 323          * @param $db DatabaseBase
 324          * @param $conditions Array
 325          * @param $flags integer (optional)
 326          * @return ResultWrapper
 327          */
 328         private static function fetchFromConds( $db, $conditions, $flags = 0 ) {
 329                 $fields = array_merge(
 330                         self::selectFields(),
 331                         self::selectPageFields(),
 332                         self::selectUserFields()
 333                 );
 334                 $options = array( 'LIMIT' => 1 );
 335                 if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
 336                         $options[] = 'FOR UPDATE';
 337                 }
 338                 return $db->select(
 339                         array( 'revision', 'page', 'user' ),
 340                         $fields,
 341                         $conditions,
 342                         __METHOD__,
 343                         $options,
 344                         array( 'page' => self::pageJoinCond(), 'user' => self::userJoinCond() )
 345                 );
 346         }
 347
 348         /**
 349          * Return the value of a select() JOIN conds array for the user table.
 350          * This will get user table rows for logged-in users.
 351          * @since 1.19
 352          * @return Array
 353          */
 354         public static function userJoinCond() {
 355                 return array( 'LEFT JOIN', array( 'rev_user != 0', 'user_id = rev_user' ) );
 356         }
 357
 358         /**
 359          * Return the value of a select() page conds array for the paeg table.
 360          * This will assure that the revision(s) are not orphaned from live pages.
 361          * @since 1.19
 362          * @return Array
 363          */
 364         public static function pageJoinCond() {
 365                 return array( 'INNER JOIN', array( 'page_id = rev_page' ) );
 366         }
 367
 368         /**
 369          * Return the list of revision fields that should be selected to create
 370          * a new revision.
 371          * @return array
 372          */
 373         public static function selectFields() {
 374                 global $wgContentHandlerUseDB;
 375
 376                 $fields = array(
 377                         'rev_id',
 378                         'rev_page',
 379                         'rev_text_id',
 380                         'rev_timestamp',
 381                         'rev_comment',
 382                         'rev_user_text',
 383                         'rev_user',
 384                         'rev_minor_edit',
 385                         'rev_deleted',
 386                         'rev_len',
 387                         'rev_parent_id',
 388                         'rev_sha1',
 389                 );
 390
 391                 if ( $wgContentHandlerUseDB ) {
 392                         $fields[] = 'rev_content_format';
 393                         $fields[] = 'rev_content_model';
 394                 }
 395
 396                 return $fields;
 397         }
 398
 399         /**
 400          * Return the list of text fields that should be selected to read the
 401          * revision text
 402          * @return array
 403          */
 404         public static function selectTextFields() {
 405                 return array(
 406                         'old_text',
 407                         'old_flags'
 408                 );
 409         }
 410
 411         /**
 412          * Return the list of page fields that should be selected from page table
 413          * @return array
 414          */
 415         public static function selectPageFields() {
 416                 return array(
 417                         'page_namespace',
 418                         'page_title',
 419                         'page_id',
 420                         'page_latest',
 421                         'page_is_redirect',
 422                         'page_len',
 423                 );
 424         }
 425
 426         /**
 427          * Return the list of user fields that should be selected from user table
 428          * @return array
 429          */
 430         public static function selectUserFields() {
 431                 return array( 'user_name' );
 432         }
 433
 434         /**
 435          * Do a batched query to get the parent revision lengths
 436          * @param $db DatabaseBase
 437          * @param $revIds Array
 438          * @return array
 439          */
 440         public static function getParentLengths( $db, array $revIds ) {
 441                 $revLens = array();
 442                 if ( !$revIds ) {
 443                         return $revLens; // empty
 444                 }
 445                 wfProfileIn( __METHOD__ );
 446                 $res = $db->select( 'revision',
 447                         array( 'rev_id', 'rev_len' ),
 448                         array( 'rev_id' => $revIds ),
 449                         __METHOD__ );
 450                 foreach ( $res as $row ) {
 451                         $revLens[$row->rev_id] = $row->rev_len;
 452                 }
 453                 wfProfileOut( __METHOD__ );
 454                 return $revLens;
 455         }
 456
 457         /**
 458          * Constructor
 459          *
 460          * @param $row Mixed: either a database row or an array
 461          * @throws MWException
 462          * @access private
 463          */
 464         function __construct( $row ) {
 465                 if( is_object( $row ) ) {
 466                         $this->mId        = intval( $row->rev_id );
 467                         $this->mPage      = intval( $row->rev_page );
 468                         $this->mTextId    = intval( $row->rev_text_id );
 469                         $this->mComment   =         $row->rev_comment;
 470                         $this->mUser      = intval( $row->rev_user );
 471                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 472                         $this->mTimestamp =         $row->rev_timestamp;
 473                         $this->mDeleted   = intval( $row->rev_deleted );
 474
 475                         if( !isset( $row->rev_parent_id ) ) {
 476                                 $this->mParentId = is_null( $row->rev_parent_id ) ? null : 0;
 477                         } else {
 478                                 $this->mParentId  = intval( $row->rev_parent_id );
 479                         }
 480
 481                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) ) {
 482                                 $this->mSize = null;
 483                         } else {
 484                                 $this->mSize = intval( $row->rev_len );
 485                         }
 486
 487                         if ( !isset( $row->rev_sha1 ) ) {
 488                                 $this->mSha1 = null;
 489                         } else {
 490                                 $this->mSha1 = $row->rev_sha1;
 491                         }
 492
 493                         if( isset( $row->page_latest ) ) {
 494                                 $this->mCurrent = ( $row->rev_id == $row->page_latest );
 495                                 $this->mTitle = Title::newFromRow( $row );
 496                         } else {
 497                                 $this->mCurrent = false;
 498                                 $this->mTitle = null;
 499                         }
 500
 501                         if( !isset( $row->rev_content_model ) || is_null( $row->rev_content_model ) ) {
 502                                 $this->mContentModel = null; # determine on demand if needed
 503                         } else {
 504                                 $this->mContentModel = strval( $row->rev_content_model );
 505                         }
 506
 507                         if( !isset( $row->rev_content_format ) || is_null( $row->rev_content_format ) ) {
 508                                 $this->mContentFormat = null; # determine on demand if needed
 509                         } else {
 510                                 $this->mContentFormat = strval( $row->rev_content_format );
 511                         }
 512
 513                         // Lazy extraction...
 514                         $this->mText      = null;
 515                         if( isset( $row->old_text ) ) {
 516                                 $this->mTextRow = $row;
 517                         } else {
 518                                 // 'text' table row entry will be lazy-loaded
 519                                 $this->mTextRow = null;
 520                         }
 521
 522                         // Use user_name for users and rev_user_text for IPs...
 523                         $this->mUserText = null; // lazy load if left null
 524                         if ( $this->mUser == 0 ) {
 525                                 $this->mUserText = $row->rev_user_text; // IP user
 526                         } elseif ( isset( $row->user_name ) ) {
 527                                 $this->mUserText = $row->user_name; // logged-in user
 528                         }
 529                         $this->mOrigUserText = $row->rev_user_text;
 530                 } elseif( is_array( $row ) ) {
 531                         // Build a new revision to be saved...
 532                         global $wgUser; // ugh
 533
 534
 535                         # if we have a content object, use it to set the model and type
 536                         if ( !empty( $row['content'] ) ) {
 537                                 //@todo: when is that set? test with external store setup! check out insertOn() [dk]
 538                                 if ( !empty( $row['text_id'] ) ) {
 539                                         throw new MWException( "Text already stored in external store (id {$row['text_id']}), "
 540                                                                                         . "can't serialize content object" );
 541                                 }
 542
 543                                 $row['content_model'] = $row['content']->getModel();
 544                                 # note: mContentFormat is initializes later accordingly
 545                                 # note: content is serialized later in this method!
 546                                 # also set text to null?
 547                         }
 548
 549                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 550                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 551                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 552                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 553                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 554                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 555                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestampNow();
 556                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 557                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 558                         $this->mParentId  = isset( $row['parent_id']  ) ? intval( $row['parent_id']  ) : null;
 559                         $this->mSha1      = isset( $row['sha1']  )      ? strval( $row['sha1']  )      : null;
 560
 561                         $this->mContentModel   = isset( $row['content_model']  )  ? strval( $row['content_model'] )  : null;
 562                         $this->mContentFormat  = isset( $row['content_format']  ) ? strval( $row['content_format'] ) : null;
 563
 564                         // Enforce spacing trimming on supplied text
 565                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 566                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 567                         $this->mTextRow   = null;
 568
 569                         $this->mTitle     = isset( $row['title']      ) ? $row['title'] : null;
 570
 571                         // if we have a Content object, override mText and mContentModel
 572                         if ( !empty( $row['content'] ) ) {
 573                                 if ( !( $row['content'] instanceof Content ) ) {
 574                                         throw new MWException( '`content` field must contain a Content object.' );
 575                                 }
 576
 577                                 $handler = $this->getContentHandler();
 578                                 $this->mContent = $row['content'];
 579
 580                                 $this->mContentModel = $this->mContent->getModel();
 581                                 $this->mContentHandler = null;
 582
 583                                 $this->mText = $handler->serializeContent( $row['content'], $this->getContentFormat() );
 584                         } elseif ( !is_null( $this->mText ) ) {
 585                                 $handler = $this->getContentHandler();
 586                                 $this->mContent = $handler->unserializeContent( $this->mText );
 587                         }
 588
 589                         // if we have a Title object, override mPage. Useful for testing and convenience.
 590                         if ( isset( $row['title'] ) ) {
 591                                 $this->mTitle     = $row['title'];
 592                                 $this->mPage      = $this->mTitle->getArticleID();
 593                         } else {
 594                                 $this->mTitle     = null; // Load on demand if needed
 595                         }
 596
 597                         // @todo: XXX: really? we are about to create a revision. it will usually then be the current one.
 598                         $this->mCurrent   = false;
 599
 600                         // If we still have no length, see it we have the text to figure it out
 601                         if ( !$this->mSize ) {
 602                                 if ( !is_null( $this->mContent ) ) {
 603                                         $this->mSize = $this->mContent->getSize();
 604                                 } else {
 605                                         #NOTE: this should never happen if we have either text or content object!
 606                                         $this->mSize = null;
 607                                 }
 608                         }
 609
 610                         // Same for sha1
 611                         if ( $this->mSha1 === null ) {
 612                                 $this->mSha1 = is_null( $this->mText ) ? null : self::base36Sha1( $this->mText );
 613                         }
 614
 615                         // force lazy init
 616                         $this->getContentModel();
 617                         $this->getContentFormat();
 618                 } else {
 619                         throw new MWException( 'Revision constructor passed invalid row format.' );
 620                 }
 621                 $this->mUnpatrolled = null;
 622         }
 623
 624         /**
 625          * Get revision ID
 626          *
 627          * @return Integer|null
 628          */
 629         public function getId() {
 630                 return $this->mId;
 631         }
 632
 633         /**
 634          * Set the revision ID
 635          *
 636          * @since 1.19
 637          * @param $id Integer
 638          */
 639         public function setId( $id ) {
 640                 $this->mId = $id;
 641         }
 642
 643         /**
 644          * Get text row ID
 645          *
 646          * @return Integer|null
 647          */
 648         public function getTextId() {
 649                 return $this->mTextId;
 650         }
 651
 652         /**
 653          * Get parent revision ID (the original previous page revision)
 654          *
 655          * @return Integer|null
 656          */
 657         public function getParentId() {
 658                 return $this->mParentId;
 659         }
 660
 661         /**
 662          * Returns the length of the text in this revision, or null if unknown.
 663          *
 664          * @return Integer|null
 665          */
 666         public function getSize() {
 667                 return $this->mSize;
 668         }
 669
 670         /**
 671          * Returns the base36 sha1 of the text in this revision, or null if unknown.
 672          *
 673          * @return String|null
 674          */
 675         public function getSha1() {
 676                 return $this->mSha1;
 677         }
 678
 679         /**
 680          * Returns the title of the page associated with this entry or null.
 681          *
 682          * Will do a query, when title is not set and id is given.
 683          *
 684          * @return Title|null
 685          */
 686         public function getTitle() {
 687                 if( isset( $this->mTitle ) ) {
 688                         return $this->mTitle;
 689                 }
 690                 if( !is_null( $this->mId ) ) { //rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
 691                         $dbr = wfGetDB( DB_SLAVE );
 692                         $row = $dbr->selectRow(
 693                                 array( 'page', 'revision' ),
 694                                 self::selectPageFields(),
 695                                 array( 'page_id=rev_page',
 696                                            'rev_id' => $this->mId ),
 697                                 __METHOD__ );
 698                         if ( $row ) {
 699                                 $this->mTitle = Title::newFromRow( $row );
 700                         }
 701                 }
 702
 703                 if ( !$this->mTitle && !is_null( $this->mPage ) && $this->mPage > 0 ) {
 704                         $this->mTitle = Title::newFromID( $this->mPage );
 705                 }
 706
 707                 return $this->mTitle;
 708         }
 709
 710         /**
 711          * Set the title of the revision
 712          *
 713          * @param $title Title
 714          */
 715         public function setTitle( $title ) {
 716                 $this->mTitle = $title;
 717         }
 718
 719         /**
 720          * Get the page ID
 721          *
 722          * @return Integer|null
 723          */
 724         public function getPage() {
 725                 return $this->mPage;
 726         }
 727
 728         /**
 729          * Fetch revision's user id if it's available to the specified audience.
 730          * If the specified audience does not have access to it, zero will be
 731          * returned.
 732          *
 733          * @param $audience Integer: one of:
 734          *      Revision::FOR_PUBLIC       to be displayed to all users
 735          *      Revision::FOR_THIS_USER    to be displayed to the given user
 736          *      Revision::RAW              get the ID regardless of permissions
 737          * @param $user User object to check for, only if FOR_THIS_USER is passed
 738          *              to the $audience parameter
 739          * @return Integer
 740          */
 741         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
 742                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 743                         return 0;
 744                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 745                         return 0;
 746                 } else {
 747                         return $this->mUser;
 748                 }
 749         }
 750
 751         /**
 752          * Fetch revision's user id without regard for the current user's permissions
 753          *
 754          * @return String
 755          */
 756         public function getRawUser() {
 757                 return $this->mUser;
 758         }
 759
 760         /**
 761          * Fetch revision's username if it's available to the specified audience.
 762          * If the specified audience does not have access to the username, an
 763          * empty string will be returned.
 764          *
 765          * @param $audience Integer: one of:
 766          *      Revision::FOR_PUBLIC       to be displayed to all users
 767          *      Revision::FOR_THIS_USER    to be displayed to the given user
 768          *      Revision::RAW              get the text regardless of permissions
 769          * @param $user User object to check for, only if FOR_THIS_USER is passed
 770          *              to the $audience parameter
 771          * @return string
 772          */
 773         public function getUserText( $audience = self::FOR_PUBLIC, User $user = null ) {
 774                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_USER ) ) {
 775                         return '';
 776                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_USER, $user ) ) {
 777                         return '';
 778                 } else {
 779                         return $this->getRawUserText();
 780                 }
 781         }
 782
 783         /**
 784          * Fetch revision's username without regard for view restrictions
 785          *
 786          * @return String
 787          */
 788         public function getRawUserText() {
 789                 if ( $this->mUserText === null ) {
 790                         $this->mUserText = User::whoIs( $this->mUser ); // load on demand
 791                         if ( $this->mUserText === false ) {
 792                                 # This shouldn't happen, but it can if the wiki was recovered
 793                                 # via importing revs and there is no user table entry yet.
 794                                 $this->mUserText = $this->mOrigUserText;
 795                         }
 796                 }
 797                 return $this->mUserText;
 798         }
 799
 800         /**
 801          * Fetch revision comment if it's available to the specified audience.
 802          * If the specified audience does not have access to the comment, an
 803          * empty string will be returned.
 804          *
 805          * @param $audience Integer: one of:
 806          *      Revision::FOR_PUBLIC       to be displayed to all users
 807          *      Revision::FOR_THIS_USER    to be displayed to the given user
 808          *      Revision::RAW              get the text regardless of permissions
 809          * @param $user User object to check for, only if FOR_THIS_USER is passed
 810          *              to the $audience parameter
 811          * @return String
 812          */
 813         function getComment( $audience = self::FOR_PUBLIC, User $user = null ) {
 814                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_COMMENT ) ) {
 815                         return '';
 816                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_COMMENT, $user ) ) {
 817                         return '';
 818                 } else {
 819                         return $this->mComment;
 820                 }
 821         }
 822
 823         /**
 824          * Fetch revision comment without regard for the current user's permissions
 825          *
 826          * @return String
 827          */
 828         public function getRawComment() {
 829                 return $this->mComment;
 830         }
 831
 832         /**
 833          * @return Boolean
 834          */
 835         public function isMinor() {
 836                 return (bool)$this->mMinorEdit;
 837         }
 838
 839         /**
 840          * @return Integer rcid of the unpatrolled row, zero if there isn't one
 841          */
 842         public function isUnpatrolled() {
 843                 if( $this->mUnpatrolled !== null ) {
 844                         return $this->mUnpatrolled;
 845                 }
 846                 $dbr = wfGetDB( DB_SLAVE );
 847                 $this->mUnpatrolled = $dbr->selectField( 'recentchanges',
 848                         'rc_id',
 849                         array( // Add redundant user,timestamp condition so we can use the existing index
 850                                 'rc_user_text'  => $this->getRawUserText(),
 851                                 'rc_timestamp'  => $dbr->timestamp( $this->getTimestamp() ),
 852                                 'rc_this_oldid' => $this->getId(),
 853                                 'rc_patrolled'  => 0
 854                         ),
 855                         __METHOD__
 856                 );
 857                 return (int)$this->mUnpatrolled;
 858         }
 859
 860         /**
 861          * @param $field int one of DELETED_* bitfield constants
 862          *
 863          * @return Boolean
 864          */
 865         public function isDeleted( $field ) {
 866                 return ( $this->mDeleted & $field ) == $field;
 867         }
 868
 869         /**
 870          * Get the deletion bitfield of the revision
 871          *
 872          * @return int
 873          */
 874         public function getVisibility() {
 875                 return (int)$this->mDeleted;
 876         }
 877
 878         /**
 879          * Fetch revision text if it's available to the specified audience.
 880          * If the specified audience does not have the ability to view this
 881          * revision, an empty string will be returned.
 882          *
 883          * @param $audience Integer: one of:
 884          *      Revision::FOR_PUBLIC       to be displayed to all users
 885          *      Revision::FOR_THIS_USER    to be displayed to the given user
 886          *      Revision::RAW              get the text regardless of permissions
 887          * @param $user User object to check for, only if FOR_THIS_USER is passed
 888          *              to the $audience parameter
 889          *
 890          * @deprecated in 1.21, use getContent() instead
 891          * @todo: replace usage in core
 892          * @return String
 893          */
 894         public function getText( $audience = self::FOR_PUBLIC, User $user = null ) {
 895                 wfDeprecated( __METHOD__, '1.21' );
 896
 897                 $content = $this->getContent( $audience, $user );
 898                 return ContentHandler::getContentText( $content ); # returns the raw content text, if applicable
 899         }
 900
 901         /**
 902          * Fetch revision content if it's available to the specified audience.
 903          * If the specified audience does not have the ability to view this
 904          * revision, null will be returned.
 905          *
 906          * @param $audience Integer: one of:
 907          *      Revision::FOR_PUBLIC       to be displayed to all users
 908          *      Revision::FOR_THIS_USER    to be displayed to $wgUser
 909          *      Revision::RAW              get the text regardless of permissions
 910          * @param $user User object to check for, only if FOR_THIS_USER is passed
 911          *              to the $audience parameter
 912          * @since 1.21
 913          * @return Content
 914          */
 915         public function getContent( $audience = self::FOR_PUBLIC, User $user = null ) {
 916                 if( $audience == self::FOR_PUBLIC && $this->isDeleted( self::DELETED_TEXT ) ) {
 917                         return null;
 918                 } elseif( $audience == self::FOR_THIS_USER && !$this->userCan( self::DELETED_TEXT, $user ) ) {
 919                         return null;
 920                 } else {
 921                         return $this->getContentInternal();
 922                 }
 923         }
 924
 925         /**
 926          * Alias for getText(Revision::FOR_THIS_USER)
 927          *
 928          * @deprecated since 1.17
 929          * @return String
 930          */
 931         public function revText() {
 932                 wfDeprecated( __METHOD__, '1.17' );
 933                 return $this->getText( self::FOR_THIS_USER );
 934         }
 935
 936         /**
 937          * Fetch revision text without regard for view restrictions
 938          *
 939          * @return String
 940          *
 941          * @deprecated since 1.21. Instead, use Revision::getContent( Revision::RAW )
 942          *                         or Revision::getSerializedData() as appropriate.
 943          */
 944         public function getRawText() {
 945                 wfDeprecated( __METHOD__, "1.21" );
 946
 947                 return $this->getText( self::RAW );
 948         }
 949
 950         /**
 951          * Fetch original serialized data without regard for view restrictions
 952          *
 953          * @since 1.21
 954          * @return String
 955          */
 956         public function getSerializedData() {
 957                 return $this->mText;
 958         }
 959
 960         /**
 961          * Gets the content object for the revision
 962          *
 963          * @since 1.21
 964          * @return Content
 965          */
 966         protected function getContentInternal() {
 967                 if( is_null( $this->mContent ) ) {
 968                         // Revision is immutable. Load on demand:
 969
 970                         $handler = $this->getContentHandler();
 971                         $format = $this->getContentFormat();
 972                         $title = $this->getTitle();
 973
 974                         if( is_null( $this->mText ) ) {
 975                                 // Load text on demand:
 976                                 $this->mText = $this->loadText();
 977                         }
 978
 979                         $this->mContent = is_null( $this->mText ) ? null : $handler->unserializeContent( $this->mText, $format );
 980                 }
 981
 982                 return $this->mContent->copy(); // NOTE: copy() will return $this for immutable content objects
 983         }
 984
 985         /**
 986          * Returns the content model for this revision.
 987          *
 988          * If no content model was stored in the database, $this->getTitle()->getContentModel() is
 989          * used to determine the content model to use. If no title is know, CONTENT_MODEL_WIKITEXT
 990          * is used as a last resort.
 991          *
 992          * @return String the content model id associated with this revision, see the CONTENT_MODEL_XXX constants.
 993          **/
 994         public function getContentModel() {
 995                 if ( !$this->mContentModel ) {
 996                         $title = $this->getTitle();
 997                         $this->mContentModel = ( $title ? $title->getContentModel() : CONTENT_MODEL_WIKITEXT );
 998
 999                         assert( !empty( $this->mContentModel ) );
1000                 }
1001
1002                 return $this->mContentModel;
1003         }
1004
1005         /**
1006          * Returns the content format for this revision.
1007          *
1008          * If no content format was stored in the database, the default format for this
1009          * revision's content model is returned.
1010          *
1011          * @return String the content format id associated with this revision, see the CONTENT_FORMAT_XXX constants.
1012          **/
1013         public function getContentFormat() {
1014                 if ( !$this->mContentFormat ) {
1015                         $handler = $this->getContentHandler();
1016                         $this->mContentFormat = $handler->getDefaultFormat();
1017
1018                         assert( !empty( $this->mContentFormat ) );
1019                 }
1020
1021                 return $this->mContentFormat;
1022         }
1023
1024         /**
1025          * Returns the content handler appropriate for this revision's content model.
1026          *
1027          * @return ContentHandler
1028          */
1029         public function getContentHandler() {
1030                 if ( !$this->mContentHandler ) {
1031                         $model = $this->getContentModel();
1032                         $this->mContentHandler = ContentHandler::getForModelID( $model );
1033
1034                         $format = $this->getContentFormat();
1035
1036                         if ( !$this->mContentHandler->isSupportedFormat( $format ) ) {
1037                                 throw new MWException( "Oops, the content format $format is not supported for this content model, $model" );
1038                         }
1039                 }
1040
1041                 return $this->mContentHandler;
1042         }
1043
1044         /**
1045          * @return String
1046          */
1047         public function getTimestamp() {
1048                 return wfTimestamp( TS_MW, $this->mTimestamp );
1049         }
1050
1051         /**
1052          * @return Boolean
1053          */
1054         public function isCurrent() {
1055                 return $this->mCurrent;
1056         }
1057
1058         /**
1059          * Get previous revision for this title
1060          *
1061          * @return Revision or null
1062          */
1063         public function getPrevious() {
1064                 if( $this->getTitle() ) {
1065                         $prev = $this->getTitle()->getPreviousRevisionID( $this->getId() );
1066                         if( $prev ) {
1067                                 return self::newFromTitle( $this->getTitle(), $prev );
1068                         }
1069                 }
1070                 return null;
1071         }
1072
1073         /**
1074          * Get next revision for this title
1075          *
1076          * @return Revision or null
1077          */
1078         public function getNext() {
1079                 if( $this->getTitle() ) {
1080                         $next = $this->getTitle()->getNextRevisionID( $this->getId() );
1081                         if ( $next ) {
1082                                 return self::newFromTitle( $this->getTitle(), $next );
1083                         }
1084                 }
1085                 return null;
1086         }
1087
1088         /**
1089          * Get previous revision Id for this page_id
1090          * This is used to populate rev_parent_id on save
1091          *
1092          * @param $db DatabaseBase
1093          * @return Integer
1094          */
1095         private function getPreviousRevisionId( $db ) {
1096                 if( is_null( $this->mPage ) ) {
1097                         return 0;
1098                 }
1099                 # Use page_latest if ID is not given
1100                 if( !$this->mId ) {
1101                         $prevId = $db->selectField( 'page', 'page_latest',
1102                                 array( 'page_id' => $this->mPage ),
1103                                 __METHOD__ );
1104                 } else {
1105                         $prevId = $db->selectField( 'revision', 'rev_id',
1106                                 array( 'rev_page' => $this->mPage, 'rev_id < ' . $this->mId ),
1107                                 __METHOD__,
1108                                 array( 'ORDER BY' => 'rev_id DESC' ) );
1109                 }
1110                 return intval( $prevId );
1111         }
1112
1113         /**
1114           * Get revision text associated with an old or archive row
1115           * $row is usually an object from wfFetchRow(), both the flags and the text
1116           * field must be included
1117           *
1118           * @param $row Object: the text data
1119           * @param $prefix String: table prefix (default 'old_')
1120           * @return String: text the text requested or false on failure
1121           */
1122         public static function getRevisionText( $row, $prefix = 'old_' ) {
1123                 wfProfileIn( __METHOD__ );
1124
1125                 # Get data
1126                 $textField = $prefix . 'text';
1127                 $flagsField = $prefix . 'flags';
1128
1129                 if( isset( $row->$flagsField ) ) {
1130                         $flags = explode( ',', $row->$flagsField );
1131                 } else {
1132                         $flags = array();
1133                 }
1134
1135                 if( isset( $row->$textField ) ) {
1136                         $text = $row->$textField;
1137                 } else {
1138                         wfProfileOut( __METHOD__ );
1139                         return false;
1140                 }
1141
1142                 # Use external methods for external objects, text in table is URL-only then
1143                 if ( in_array( 'external', $flags ) ) {
1144                         $url = $text;
1145                         $parts = explode( '://', $url, 2 );
1146                         if( count( $parts ) == 1 || $parts[1] == '' ) {
1147                                 wfProfileOut( __METHOD__ );
1148                                 return false;
1149                         }
1150                         $text = ExternalStore::fetchFromURL( $url );
1151                 }
1152
1153                 // If the text was fetched without an error, convert it
1154                 if ( $text !== false ) {
1155                         if( in_array( 'gzip', $flags ) ) {
1156                                 # Deal with optional compression of archived pages.
1157                                 # This can be done periodically via maintenance/compressOld.php, and
1158                                 # as pages are saved if $wgCompressRevisions is set.
1159                                 $text = gzinflate( $text );
1160                         }
1161
1162                         if( in_array( 'object', $flags ) ) {
1163                                 # Generic compressed storage
1164                                 $obj = unserialize( $text );
1165                                 if ( !is_object( $obj ) ) {
1166                                         // Invalid object
1167                                         wfProfileOut( __METHOD__ );
1168                                         return false;
1169                                 }
1170                                 $text = $obj->getText();
1171                         }
1172
1173                         global $wgLegacyEncoding;
1174                         if( $text !== false && $wgLegacyEncoding
1175                                 && !in_array( 'utf-8', $flags ) && !in_array( 'utf8', $flags ) )
1176                         {
1177                                 # Old revisions kept around in a legacy encoding?
1178                                 # Upconvert on demand.
1179                                 # ("utf8" checked for compatibility with some broken
1180                                 #  conversion scripts 2008-12-30)
1181                                 global $wgContLang;
1182                                 $text = $wgContLang->iconv( $wgLegacyEncoding, 'UTF-8', $text );
1183                         }
1184                 }
1185                 wfProfileOut( __METHOD__ );
1186                 return $text;
1187         }
1188
1189         /**
1190          * If $wgCompressRevisions is enabled, we will compress data.
1191          * The input string is modified in place.
1192          * Return value is the flags field: contains 'gzip' if the
1193          * data is compressed, and 'utf-8' if we're saving in UTF-8
1194          * mode.
1195          *
1196          * @param $text Mixed: reference to a text
1197          * @return String
1198          */
1199         public static function compressRevisionText( &$text ) {
1200                 global $wgCompressRevisions;
1201                 $flags = array();
1202
1203                 # Revisions not marked this way will be converted
1204                 # on load if $wgLegacyCharset is set in the future.
1205                 $flags[] = 'utf-8';
1206
1207                 if( $wgCompressRevisions ) {
1208                         if( function_exists( 'gzdeflate' ) ) {
1209                                 $text = gzdeflate( $text );
1210                                 $flags[] = 'gzip';
1211                         } else {
1212                                 wfDebug( __METHOD__ . " -- no zlib support, not compressing\n" );
1213                         }
1214                 }
1215                 return implode( ',', $flags );
1216         }
1217
1218         /**
1219          * Insert a new revision into the database, returning the new revision ID
1220          * number on success and dies horribly on failure.
1221          *
1222          * @param $dbw DatabaseBase: (master connection)
1223          * @throws MWException
1224          * @return Integer
1225          */
1226         public function insertOn( $dbw ) {
1227                 global $wgDefaultExternalStore, $wgContentHandlerUseDB;
1228
1229                 wfProfileIn( __METHOD__ );
1230
1231                 $this->checkContentModel();
1232
1233                 $data = $this->mText;
1234                 $flags = self::compressRevisionText( $data );
1235
1236                 # Write to external storage if required
1237                 if( $wgDefaultExternalStore ) {
1238                         // Store and get the URL
1239                         $data = ExternalStore::insertToDefault( $data );
1240                         if( !$data ) {
1241                                 throw new MWException( "Unable to store text to external storage" );
1242                         }
1243                         if( $flags ) {
1244                                 $flags .= ',';
1245                         }
1246                         $flags .= 'external';
1247                 }
1248
1249                 # Record the text (or external storage URL) to the text table
1250                 if( !isset( $this->mTextId ) ) {
1251                         $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
1252                         $dbw->insert( 'text',
1253                                 array(
1254                                         'old_id'    => $old_id,
1255                                         'old_text'  => $data,
1256                                         'old_flags' => $flags,
1257                                 ), __METHOD__
1258                         );
1259                         $this->mTextId = $dbw->insertId();
1260                 }
1261
1262                 if ( $this->mComment === null ) $this->mComment = "";
1263
1264                 # Record the edit in revisions
1265                 $rev_id = isset( $this->mId )
1266                         ? $this->mId
1267                         : $dbw->nextSequenceValue( 'revision_rev_id_seq' );
1268                 $row = array(
1269                         'rev_id'         => $rev_id,
1270                         'rev_page'       => $this->mPage,
1271                         'rev_text_id'    => $this->mTextId,
1272                         'rev_comment'    => $this->mComment,
1273                         'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
1274                         'rev_user'       => $this->mUser,
1275                         'rev_user_text'  => $this->mUserText,
1276                         'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
1277                         'rev_deleted'    => $this->mDeleted,
1278                         'rev_len'        => $this->mSize,
1279                         'rev_parent_id'  => is_null( $this->mParentId )
1280                                 ? $this->getPreviousRevisionId( $dbw )
1281                                 : $this->mParentId,
1282                         'rev_sha1'       => is_null( $this->mSha1 )
1283                                 ? Revision::base36Sha1( $this->mText )
1284                                 : $this->mSha1,
1285                 );
1286
1287                 if ( $wgContentHandlerUseDB ) {
1288                         //NOTE: Store null for the default model and format, to save space.
1289                         //XXX: Makes the DB sensitive to changed defaults. Make this behaviour optional? Only in miser mode?
1290
1291                         $model = $this->getContentModel();
1292                         $format = $this->getContentFormat();
1293
1294                         $title = $this->getTitle();
1295
1296                         if ( $title === null ) {
1297                                 throw new MWException( "Insufficient information to determine the title of the revision's page!" );
1298                         }
1299
1300                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1301                         $defaultFormat = ContentHandler::getForModelID( $defaultModel )->getDefaultFormat();
1302
1303                         $row[ 'rev_content_model' ] = ( $model === $defaultModel ) ? null : $model;
1304                         $row[ 'rev_content_format' ] = ( $format === $defaultFormat ) ? null : $format;
1305                 }
1306
1307                 $dbw->insert( 'revision', $row, __METHOD__ );
1308
1309                 $this->mId = !is_null( $rev_id ) ? $rev_id : $dbw->insertId();
1310
1311                 wfRunHooks( 'RevisionInsertComplete', array( &$this, $data, $flags ) );
1312
1313                 wfProfileOut( __METHOD__ );
1314                 return $this->mId;
1315         }
1316
1317         protected function checkContentModel() {
1318                 global $wgContentHandlerUseDB;
1319
1320                 $title = $this->getTitle(); //note: may return null for revisions that have not yet been inserted.
1321
1322                 $model = $this->getContentModel();
1323                 $format = $this->getContentFormat();
1324                 $handler = $this->getContentHandler();
1325
1326                 if ( !$handler->isSupportedFormat( $format ) ) {
1327                         $t = $title->getPrefixedDBkey();
1328
1329                         throw new MWException( "Can't use format $format with content model $model on $t" );
1330                 }
1331
1332                 if ( !$wgContentHandlerUseDB && $title ) {
1333                         // if $wgContentHandlerUseDB is not set, all revisions must use the default content model and format.
1334
1335                         $defaultModel = ContentHandler::getDefaultModelFor( $title );
1336                         $defaultHandler = ContentHandler::getForModelID( $defaultModel );
1337                         $defaultFormat = $defaultHandler->getDefaultFormat();
1338
1339                         if ( $this->getContentModel() != $defaultModel ) {
1340                                 $t = $title->getPrefixedDBkey();
1341
1342                                 throw new MWException( "Can't save non-default content model with \$wgContentHandlerUseDB disabled: "
1343                                                                                 . "model is $model , default for $t is $defaultModel" );
1344                         }
1345
1346                         if ( $this->getContentFormat() != $defaultFormat ) {
1347                                 $t = $title->getPrefixedDBkey();
1348
1349                                 throw new MWException( "Can't use non-default content format with \$wgContentHandlerUseDB disabled: "
1350                                                                                 . "format is $format, default for $t is $defaultFormat" );
1351                         }
1352                 }
1353
1354                 $content = $this->getContent( Revision::RAW );
1355
1356                 if ( !$content->isValid() ) {
1357                         $t = $title->getPrefixedDBkey();
1358
1359                         throw new MWException( "Content of $t is not valid! Content model is $model" );
1360                 }
1361         }
1362
1363         /**
1364          * Get the base 36 SHA-1 value for a string of text
1365          * @param $text String
1366          * @return String
1367          */
1368         public static function base36Sha1( $text ) {
1369                 return wfBaseConvert( sha1( $text ), 16, 36, 31 );
1370         }
1371
1372         /**
1373          * Lazy-load the revision's text.
1374          * Currently hardcoded to the 'text' table storage engine.
1375          *
1376          * @return String
1377          */
1378         protected function loadText() {
1379                 wfProfileIn( __METHOD__ );
1380
1381                 // Caching may be beneficial for massive use of external storage
1382                 global $wgRevisionCacheExpiry, $wgMemc;
1383                 $textId = $this->getTextId();
1384                 $key = wfMemcKey( 'revisiontext', 'textid', $textId );
1385                 if( $wgRevisionCacheExpiry ) {
1386                         $text = $wgMemc->get( $key );
1387                         if( is_string( $text ) ) {
1388                                 wfDebug( __METHOD__ . ": got id $textId from cache\n" );
1389                                 wfProfileOut( __METHOD__ );
1390                                 return $text;
1391                         }
1392                 }
1393
1394                 // If we kept data for lazy extraction, use it now...
1395                 if ( isset( $this->mTextRow ) ) {
1396                         $row = $this->mTextRow;
1397                         $this->mTextRow = null;
1398                 } else {
1399                         $row = null;
1400                 }
1401
1402                 if( !$row ) {
1403                         // Text data is immutable; check slaves first.
1404                         $dbr = wfGetDB( DB_SLAVE );
1405                         $row = $dbr->selectRow( 'text',
1406                                 array( 'old_text', 'old_flags' ),
1407                                 array( 'old_id' => $this->getTextId() ),
1408                                 __METHOD__ );
1409                 }
1410
1411                 if( !$row && wfGetLB()->getServerCount() > 1 ) {
1412                         // Possible slave lag!
1413                         $dbw = wfGetDB( DB_MASTER );
1414                         $row = $dbw->selectRow( 'text',
1415                                 array( 'old_text', 'old_flags' ),
1416                                 array( 'old_id' => $this->getTextId() ),
1417                                 __METHOD__ );
1418                 }
1419
1420                 $text = self::getRevisionText( $row );
1421
1422                 # No negative caching -- negative hits on text rows may be due to corrupted slave servers
1423                 if( $wgRevisionCacheExpiry && $text !== false ) {
1424                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
1425                 }
1426
1427                 wfProfileOut( __METHOD__ );
1428
1429                 return $text;
1430         }
1431
1432         /**
1433          * Create a new null-revision for insertion into a page's
1434          * history. This will not re-save the text, but simply refer
1435          * to the text from the previous version.
1436          *
1437          * Such revisions can for instance identify page rename
1438          * operations and other such meta-modifications.
1439          *
1440          * @param $dbw DatabaseBase
1441          * @param $pageId Integer: ID number of the page to read from
1442          * @param $summary String: revision's summary
1443          * @param $minor Boolean: whether the revision should be considered as minor
1444          * @return Revision|null on error
1445          */
1446         public static function newNullRevision( $dbw, $pageId, $summary, $minor ) {
1447                 global $wgContentHandlerUseDB;
1448
1449                 wfProfileIn( __METHOD__ );
1450
1451                 $fields = array( 'page_latest', 'page_namespace', 'page_title',
1452                                                 'rev_text_id', 'rev_len', 'rev_sha1' );
1453
1454                 if ( $wgContentHandlerUseDB ) {
1455                         $fields[] = 'rev_content_model';
1456                         $fields[] = 'rev_content_format';
1457                 }
1458
1459                 $current = $dbw->selectRow(
1460                         array( 'page', 'revision' ),
1461                         $fields,
1462                         array(
1463                                 'page_id' => $pageId,
1464                                 'page_latest=rev_id',
1465                                 ),
1466                         __METHOD__ );
1467
1468                 if( $current ) {
1469                         $row = array(
1470                                 'page'       => $pageId,
1471                                 'comment'    => $summary,
1472                                 'minor_edit' => $minor,
1473                                 'text_id'    => $current->rev_text_id,
1474                                 'parent_id'  => $current->page_latest,
1475                                 'len'        => $current->rev_len,
1476                                 'sha1'       => $current->rev_sha1
1477                         );
1478
1479                         if ( $wgContentHandlerUseDB ) {
1480                                 $row[ 'content_model' ] = $current->rev_content_model;
1481                                 $row[ 'content_format' ] = $current->rev_content_format;
1482                         }
1483
1484                         $revision = new Revision( $row );
1485                         $revision->setTitle( Title::makeTitle( $current->page_namespace, $current->page_title ) );
1486                 } else {
1487                         $revision = null;
1488                 }
1489
1490                 wfProfileOut( __METHOD__ );
1491                 return $revision;
1492         }
1493
1494         /**
1495          * Determine if the current user is allowed to view a particular
1496          * field of this revision, if it's marked as deleted.
1497          *
1498          * @param $field Integer:one of self::DELETED_TEXT,
1499          *                              self::DELETED_COMMENT,
1500          *                              self::DELETED_USER
1501          * @param $user User object to check, or null to use $wgUser
1502          * @return Boolean
1503          */
1504         public function userCan( $field, User $user = null ) {
1505                 return self::userCanBitfield( $this->mDeleted, $field, $user );
1506         }
1507
1508         /**
1509          * Determine if the current user is allowed to view a particular
1510          * field of this revision, if it's marked as deleted. This is used
1511          * by various classes to avoid duplication.
1512          *
1513          * @param $bitfield Integer: current field
1514          * @param $field Integer: one of self::DELETED_TEXT = File::DELETED_FILE,
1515          *                               self::DELETED_COMMENT = File::DELETED_COMMENT,
1516          *                               self::DELETED_USER = File::DELETED_USER
1517          * @param $user User object to check, or null to use $wgUser
1518          * @return Boolean
1519          */
1520         public static function userCanBitfield( $bitfield, $field, User $user = null ) {
1521                 if( $bitfield & $field ) { // aspect is deleted
1522                         if ( $bitfield & self::DELETED_RESTRICTED ) {
1523                                 $permission = 'suppressrevision';
1524                         } elseif ( $field & self::DELETED_TEXT ) {
1525                                 $permission = 'deletedtext';
1526                         } else {
1527                                 $permission = 'deletedhistory';
1528                         }
1529                         wfDebug( "Checking for $permission due to $field match on $bitfield\n" );
1530                         if ( $user === null ) {
1531                                 global $wgUser;
1532                                 $user = $wgUser;
1533                         }
1534                         return $user->isAllowed( $permission );
1535                 } else {
1536                         return true;
1537                 }
1538         }
1539
1540         /**
1541          * Get rev_timestamp from rev_id, without loading the rest of the row
1542          *
1543          * @param $title Title
1544          * @param $id Integer
1545          * @return String
1546          */
1547         static function getTimestampFromId( $title, $id ) {
1548                 $dbr = wfGetDB( DB_SLAVE );
1549                 // Casting fix for DB2
1550                 if ( $id == '' ) {
1551                         $id = 0;
1552                 }
1553                 $conds = array( 'rev_id' => $id );
1554                 $conds['rev_page'] = $title->getArticleID();
1555                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1556                 if ( $timestamp === false && wfGetLB()->getServerCount() > 1 ) {
1557                         # Not in slave, try master
1558                         $dbw = wfGetDB( DB_MASTER );
1559                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp', $conds, __METHOD__ );
1560                 }
1561                 return wfTimestamp( TS_MW, $timestamp );
1562         }
1563
1564         /**
1565          * Get count of revisions per page...not very efficient
1566          *
1567          * @param $db DatabaseBase
1568          * @param $id Integer: page id
1569          * @return Integer
1570          */
1571         static function countByPageId( $db, $id ) {
1572                 $row = $db->selectRow( 'revision', array( 'revCount' => 'COUNT(*)' ),
1573                         array( 'rev_page' => $id ), __METHOD__ );
1574                 if( $row ) {
1575                         return $row->revCount;
1576                 }
1577                 return 0;
1578         }
1579
1580         /**
1581          * Get count of revisions per page...not very efficient
1582          *
1583          * @param $db DatabaseBase
1584          * @param $title Title
1585          * @return Integer
1586          */
1587         static function countByTitle( $db, $title ) {
1588                 $id = $title->getArticleID();
1589                 if( $id ) {
1590                         return self::countByPageId( $db, $id );
1591                 }
1592                 return 0;
1593         }
1594
1595         /**
1596          * Check if no edits were made by other users since
1597          * the time a user started editing the page. Limit to
1598          * 50 revisions for the sake of performance.
1599          *
1600          * @since 1.20
1601          *
1602          * @param DatabaseBase|int $db the Database to perform the check on. May be given as a Database object or
1603          *        a database identifier usable with wfGetDB.
1604          * @param int $pageId the ID of the page in question
1605          * @param int $userId the ID of the user in question
1606          * @param string $since look at edits since this time
1607          *
1608          * @return bool True if the given user was the only one to edit since the given timestamp
1609          */
1610         public static function userWasLastToEdit( $db, $pageId, $userId, $since ) {
1611                 if ( !$userId ) return false;
1612
1613                 if ( is_int( $db ) ) {
1614                         $db = wfGetDB( $db );
1615                 }
1616
1617                 $res = $db->select( 'revision',
1618                         'rev_user',
1619                         array(
1620                                 'rev_page' => $pageId,
1621                                 'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
1622                         ),
1623                         __METHOD__,
1624                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ) );
1625                 foreach ( $res as $row ) {
1626                         if ( $row->rev_user != $userId ) {
1627                                 return false;
1628                         }
1629                 }
1630                 return true;
1631         }
1632 }