includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  * @package MediaWiki
   6  */
   7
   8 /** Number of times to re-try an operation in case of deadlock */
   9 define( 'DEADLOCK_TRIES', 4 );
  10 /** Minimum time to wait before retry, in microseconds */
  11 define( 'DEADLOCK_DELAY_MIN', 500000 );
  12 /** Maximum time to wait before retry */
  13 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  14
  15 /******************************************************************************
  16  * Utility classes
  17  *****************************************************************************/
  18
  19 class DBObject {
  20         public $mData;
  21
  22         function DBObject($data) {
  23                 $this->mData = $data;
  24         }
  25
  26         function isLOB() {
  27                 return false;
  28         }
  29
  30         function data() {
  31                 return $this->mData;
  32         }
  33 };
  34
  35 /******************************************************************************
  36  * Error classes
  37  *****************************************************************************/
  38
  39 /**
  40  * Database error base class
  41  */
  42 class DBError extends MWException {
  43         public $db;
  44
  45         /**
  46          * Construct a database error
  47          * @param Database $db The database object which threw the error
  48          * @param string $error A simple error message to be used for debugging
  49          */
  50         function __construct( Database &$db, $error ) {
  51                 $this->db =& $db;
  52                 parent::__construct( $error );
  53         }
  54 }
  55
  56 class DBConnectionError extends DBError {
  57         public $error;
  58
  59         function __construct( Database &$db, $error = 'unknown error' ) {
  60                 $msg = 'DB connection error';
  61                 if ( trim( $error ) != '' ) {
  62                         $msg .= ": $error";
  63                 }
  64                 $this->error = $error;
  65                 parent::__construct( $db, $msg );
  66         }
  67
  68         function useOutputPage() {
  69                 // Not likely to work
  70                 return false;
  71         }
  72
  73         function useMessageCache() {
  74                 // Not likely to work
  75                 return false;
  76         }
  77
  78         function getText() {
  79                 return $this->getMessage() . "\n";
  80         }
  81
  82         function getLogMessage() {
  83                 # Don't send to the exception log
  84                 return false;
  85         }
  86
  87         function getPageTitle() {
  88                 global $wgSitename;
  89                 return "$wgSitename has a problem";
  90         }
  91
  92         function getHTML() {
  93                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
  94                 global $wgSitename, $wgServer, $wgMessageCache;
  95
  96                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
  97                 # Hard coding strings instead.
  98
  99                 $noconnect = "<p><strong>Sorry! This site is experiencing technical difficulties.</strong></p><p>Try waiting a few minutes and reloading.</p><p><small>(Can't contact the database server: $1)</small></p>";
 100                 $mainpage = 'Main Page';
 101                 $searchdisabled = <<<EOT
 102 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
 103 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
 104 EOT;
 105
 106                 $googlesearch = "
 107 <!-- SiteSearch Google -->
 108 <FORM method=GET action=\"http://www.google.com/search\">
 109 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
 110 <A HREF=\"http://www.google.com/\">
 111 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
 112 border=\"0\" ALT=\"Google\"></A>
 113 </td>
 114 <td>
 115 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
 116 <INPUT type=submit name=btnG VALUE=\"Google Search\">
 117 <font size=-1>
 118 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
 119 <input type='hidden' name='ie' value='$2'>
 120 <input type='hidden' name='oe' value='$2'>
 121 </font>
 122 </td></tr></TABLE>
 123 </FORM>
 124 <!-- SiteSearch Google -->";
 125                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
 126
 127                 # No database access
 128                 if ( is_object( $wgMessageCache ) ) {
 129                         $wgMessageCache->disable();
 130                 }
 131
 132                 if ( trim( $this->error ) == '' ) {
 133                         $this->error = $this->db->getProperty('mServer');
 134                 }
 135
 136                 $text = str_replace( '$1', $this->error, $noconnect );
 137                 $text .= wfGetSiteNotice();
 138
 139                 if($wgUseFileCache) {
 140                         if($wgTitle) {
 141                                 $t =& $wgTitle;
 142                         } else {
 143                                 if($title) {
 144                                         $t = Title::newFromURL( $title );
 145                                 } elseif (@/**/$_REQUEST['search']) {
 146                                         $search = $_REQUEST['search'];
 147                                         return $searchdisabled .
 148                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
 149                                           $wgInputEncoding ), $googlesearch );
 150                                 } else {
 151                                         $t = Title::newFromText( $mainpage );
 152                                 }
 153                         }
 154
 155                         $cache = new HTMLFileCache( $t );
 156                         if( $cache->isFileCached() ) {
 157                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
 158                                         $cachederror . "</b></p>\n";
 159
 160                                 $tag = '<div id="article">';
 161                                 $text = str_replace(
 162                                         $tag,
 163                                         $tag . $msg,
 164                                         $cache->fetchPageText() );
 165                         }
 166                 }
 167
 168                 return $text;
 169         }
 170 }
 171
 172 class DBQueryError extends DBError {
 173         public $error, $errno, $sql, $fname;
 174
 175         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
 176                 $message = "A database error has occurred\n" .
 177                   "Query: $sql\n" .
 178                   "Function: $fname\n" .
 179                   "Error: $errno $error\n";
 180
 181                 parent::__construct( $db, $message );
 182                 $this->error = $error;
 183                 $this->errno = $errno;
 184                 $this->sql = $sql;
 185                 $this->fname = $fname;
 186         }
 187
 188         function getText() {
 189                 if ( $this->useMessageCache() ) {
 190                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
 191                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
 192                 } else {
 193                         return $this->getMessage();
 194                 }
 195         }
 196
 197         function getSQL() {
 198                 global $wgShowSQLErrors;
 199                 if( !$wgShowSQLErrors ) {
 200                         return $this->msg( 'sqlhidden', 'SQL hidden' );
 201                 } else {
 202                         return $this->sql;
 203                 }
 204         }
 205
 206         function getLogMessage() {
 207                 # Don't send to the exception log
 208                 return false;
 209         }
 210
 211         function getPageTitle() {
 212                 return $this->msg( 'databaseerror', 'Database error' );
 213         }
 214
 215         function getHTML() {
 216                 if ( $this->useMessageCache() ) {
 217                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
 218                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
 219                 } else {
 220                         return nl2br( htmlspecialchars( $this->getMessage() ) );
 221                 }
 222         }
 223 }
 224
 225 class DBUnexpectedError extends DBError {}
 226
 227 /******************************************************************************/
 228
 229 /**
 230  * Database abstraction object
 231  * @package MediaWiki
 232  */
 233 class Database {
 234
 235 #------------------------------------------------------------------------------
 236 # Variables
 237 #------------------------------------------------------------------------------
 238
 239         protected $mLastQuery = '';
 240
 241         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 242         protected $mOut, $mOpened = false;
 243
 244         protected $mFailFunction;
 245         protected $mTablePrefix;
 246         protected $mFlags;
 247         protected $mTrxLevel = 0;
 248         protected $mErrorCount = 0;
 249         protected $mLBInfo = array();
 250         protected $mCascadingDeletes = false;
 251         protected $mCleanupTriggers = false;
 252         protected $mStrictIPs = false;
 253
 254 #------------------------------------------------------------------------------
 255 # Accessors
 256 #------------------------------------------------------------------------------
 257         # These optionally set a variable and return the previous state
 258
 259         /**
 260          * Fail function, takes a Database as a parameter
 261          * Set to false for default, 1 for ignore errors
 262          */
 263         function failFunction( $function = NULL ) {
 264                 return wfSetVar( $this->mFailFunction, $function );
 265         }
 266
 267         /**
 268          * Output page, used for reporting errors
 269          * FALSE means discard output
 270          */
 271         function setOutputPage( $out ) {
 272                 $this->mOut = $out;
 273         }
 274
 275         /**
 276          * Boolean, controls output of large amounts of debug information
 277          */
 278         function debug( $debug = NULL ) {
 279                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
 280         }
 281
 282         /**
 283          * Turns buffering of SQL result sets on (true) or off (false).
 284          * Default is "on" and it should not be changed without good reasons.
 285          */
 286         function bufferResults( $buffer = NULL ) {
 287                 if ( is_null( $buffer ) ) {
 288                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 289                 } else {
 290                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 291                 }
 292         }
 293
 294         /**
 295          * Turns on (false) or off (true) the automatic generation and sending
 296          * of a "we're sorry, but there has been a database error" page on
 297          * database errors. Default is on (false). When turned off, the
 298          * code should use lastErrno() and lastError() to handle the
 299          * situation as appropriate.
 300          */
 301         function ignoreErrors( $ignoreErrors = NULL ) {
 302                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 303         }
 304
 305         /**
 306          * The current depth of nested transactions
 307          * @param $level Integer: , default NULL.
 308          */
 309         function trxLevel( $level = NULL ) {
 310                 return wfSetVar( $this->mTrxLevel, $level );
 311         }
 312
 313         /**
 314          * Number of errors logged, only useful when errors are ignored
 315          */
 316         function errorCount( $count = NULL ) {
 317                 return wfSetVar( $this->mErrorCount, $count );
 318         }
 319
 320         /**
 321          * Properties passed down from the server info array of the load balancer
 322          */
 323         function getLBInfo( $name = NULL ) {
 324                 if ( is_null( $name ) ) {
 325                         return $this->mLBInfo;
 326                 } else {
 327                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 328                                 return $this->mLBInfo[$name];
 329                         } else {
 330                                 return NULL;
 331                         }
 332                 }
 333         }
 334
 335         function setLBInfo( $name, $value = NULL ) {
 336                 if ( is_null( $value ) ) {
 337                         $this->mLBInfo = $name;
 338                 } else {
 339                         $this->mLBInfo[$name] = $value;
 340                 }
 341         }
 342
 343         /**
 344          * Returns true if this database supports (and uses) cascading deletes
 345          */
 346         function cascadingDeletes() {
 347                 return $this->mCascadingDeletes;
 348         }
 349
 350         /**
 351          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 352          */
 353         function cleanupTriggers() {
 354                 return $this->mCleanupTriggers;
 355         }
 356
 357         /**
 358          * Returns true if this database is strict about what can be put into an IP field.
 359          * Specifically, it uses a NULL value instead of an empty string.
 360          */
 361         function strictIPs() {
 362                 return $this->mStrictIPs;
 363         }
 364
 365         /**
 366          * Returns true if this database uses timestamps rather than integers
 367         */
 368         function realTimestamps() {
 369                 return false;
 370         }
 371
 372         /**#@+
 373          * Get function
 374          */
 375         function lastQuery() { return $this->mLastQuery; }
 376         function isOpen() { return $this->mOpened; }
 377         /**#@-*/
 378
 379         function setFlag( $flag ) {
 380                 $this->mFlags |= $flag;
 381         }
 382
 383         function clearFlag( $flag ) {
 384                 $this->mFlags &= ~$flag;
 385         }
 386
 387         function getFlag( $flag ) {
 388                 return !!($this->mFlags & $flag);
 389         }
 390
 391         /**
 392          * General read-only accessor
 393          */
 394         function getProperty( $name ) {
 395                 return $this->$name;
 396         }
 397
 398 #------------------------------------------------------------------------------
 399 # Other functions
 400 #------------------------------------------------------------------------------
 401
 402         /**@{{
 403          * @param string $server database server host
 404          * @param string $user database user name
 405          * @param string $password database user password
 406          * @param string $dbname database name
 407          */
 408
 409         /**
 410          * @param failFunction
 411          * @param $flags
 412          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 413          */
 414         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 415                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 416
 417                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 418                 # Can't get a reference if it hasn't been set yet
 419                 if ( !isset( $wgOut ) ) {
 420                         $wgOut = NULL;
 421                 }
 422                 $this->mOut =& $wgOut;
 423
 424                 $this->mFailFunction = $failFunction;
 425                 $this->mFlags = $flags;
 426
 427                 if ( $this->mFlags & DBO_DEFAULT ) {
 428                         if ( $wgCommandLineMode ) {
 429                                 $this->mFlags &= ~DBO_TRX;
 430                         } else {
 431                                 $this->mFlags |= DBO_TRX;
 432                         }
 433                 }
 434
 435                 /*
 436                 // Faster read-only access
 437                 if ( wfReadOnly() ) {
 438                         $this->mFlags |= DBO_PERSISTENT;
 439                         $this->mFlags &= ~DBO_TRX;
 440                 }*/
 441
 442                 /** Get the default table prefix*/
 443                 if ( $tablePrefix == 'get from global' ) {
 444                         $this->mTablePrefix = $wgDBprefix;
 445                 } else {
 446                         $this->mTablePrefix = $tablePrefix;
 447                 }
 448
 449                 if ( $server ) {
 450                         $this->open( $server, $user, $password, $dbName );
 451                 }
 452         }
 453
 454         /**
 455          * @static
 456          * @param failFunction
 457          * @param $flags
 458          */
 459         static function newFromParams( $server, $user, $password, $dbName,
 460                 $failFunction = false, $flags = 0 )
 461         {
 462                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 463         }
 464
 465         /**
 466          * Usually aborts on failure
 467          * If the failFunction is set to a non-zero integer, returns success
 468          */
 469         function open( $server, $user, $password, $dbName ) {
 470                 global $wguname;
 471                 wfProfileIn( __METHOD__ );
 472
 473                 # Test for missing mysql.so
 474                 # First try to load it
 475                 if (!@extension_loaded('mysql')) {
 476                         @dl('mysql.so');
 477                 }
 478
 479                 # Fail now
 480                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 481                 if ( !function_exists( 'mysql_connect' ) ) {
 482                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 483                 }
 484
 485                 $this->close();
 486                 $this->mServer = $server;
 487                 $this->mUser = $user;
 488                 $this->mPassword = $password;
 489                 $this->mDBname = $dbName;
 490
 491                 $success = false;
 492
 493                 wfProfileIn("dbconnect-$server");
 494
 495                 # LIVE PATCH by Tim, ask Domas for why: retry loop
 496                 $this->mConn = false;
 497                 $max = 3;
 498                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 499                         if ( $i > 1 ) {
 500                                 usleep( 1000 );
 501                         }
 502                         if ( $this->mFlags & DBO_PERSISTENT ) {
 503                                 @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 504                         } else {
 505                                 # Create a new connection...
 506                                 @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 507                         }
 508                         if ($this->mConn === false) {
 509                                 $iplus = $i + 1;
 510                                 wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 511                         }
 512                 }
 513
 514                 wfProfileOut("dbconnect-$server");
 515
 516                 if ( $dbName != '' ) {
 517                         if ( $this->mConn !== false ) {
 518                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 519                                 if ( !$success ) {
 520                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 521                                                 "from client host {$wguname['nodename']}\n";
 522                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 523                                         wfDebug( $error );
 524                                 }
 525                         } else {
 526                                 wfDebug( "DB connection error\n" );
 527                                 wfDebug( "Server: $server, User: $user, Password: " .
 528                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 529                                 $success = false;
 530                         }
 531                 } else {
 532                         # Delay USE query
 533                         $success = (bool)$this->mConn;
 534                 }
 535
 536                 if ( $success ) {
 537                         global $wgDBmysql5;
 538                         if( $wgDBmysql5 ) {
 539                                 // Tell the server we're communicating with it in UTF-8.
 540                                 // This may engage various charset conversions.
 541                                 $this->query( 'SET NAMES utf8' );
 542                         }
 543                 } else {
 544                         $this->reportConnectionError();
 545                 }
 546
 547                 $this->mOpened = $success;
 548                 wfProfileOut( __METHOD__ );
 549                 return $success;
 550         }
 551         /**@}}*/
 552
 553         /**
 554          * Closes a database connection.
 555          * if it is open : commits any open transactions
 556          *
 557          * @return bool operation success. true if already closed.
 558          */
 559         function close()
 560         {
 561                 $this->mOpened = false;
 562                 if ( $this->mConn ) {
 563                         if ( $this->trxLevel() ) {
 564                                 $this->immediateCommit();
 565                         }
 566                         return mysql_close( $this->mConn );
 567                 } else {
 568                         return true;
 569                 }
 570         }
 571
 572         /**
 573          * @param string $error fallback error message, used if none is given by MySQL
 574          */
 575         function reportConnectionError( $error = 'Unknown error' ) {
 576                 $myError = $this->lastError();
 577                 if ( $myError ) {
 578                         $error = $myError;
 579                 }
 580
 581                 if ( $this->mFailFunction ) {
 582                         # Legacy error handling method
 583                         if ( !is_int( $this->mFailFunction ) ) {
 584                                 $ff = $this->mFailFunction;
 585                                 $ff( $this, $error );
 586                         }
 587                 } else {
 588                         # New method
 589                         wfLogDBError( "Connection error: $error\n" );
 590                         throw new DBConnectionError( $this, $error );
 591                 }
 592         }
 593
 594         /**
 595          * Usually aborts on failure
 596          * If errors are explicitly ignored, returns success
 597          */
 598         function query( $sql, $fname = '', $tempIgnore = false ) {
 599                 global $wgProfiling;
 600
 601                 if ( $wgProfiling ) {
 602                         # generalizeSQL will probably cut down the query to reasonable
 603                         # logging size most of the time. The substr is really just a sanity check.
 604
 605                         # Who's been wasting my precious column space? -- TS
 606                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 607
 608                         if ( is_null( $this->getLBInfo( 'master' ) ) ) {
 609                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 610                                 $totalProf = 'Database::query';
 611                         } else {
 612                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 613                                 $totalProf = 'Database::query-master';
 614                         }
 615                         wfProfileIn( $totalProf );
 616                         wfProfileIn( $queryProf );
 617                 }
 618
 619                 $this->mLastQuery = $sql;
 620
 621                 # Add a comment for easy SHOW PROCESSLIST interpretation
 622                 if ( $fname ) {
 623                         $commentedSql = preg_replace('/\s/', " /* $fname */ ", $sql, 1);
 624                 } else {
 625                         $commentedSql = $sql;
 626                 }
 627
 628                 # If DBO_TRX is set, start a transaction
 629                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 630                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK'
 631                 ) {
 632                         $this->begin();
 633                 }
 634
 635                 if ( $this->debug() ) {
 636                         $sqlx = substr( $commentedSql, 0, 500 );
 637                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 638                         wfDebug( "SQL: $sqlx\n" );
 639                 }
 640
 641                 # Do the query and handle errors
 642                 $ret = $this->doQuery( $commentedSql );
 643
 644                 # Try reconnecting if the connection was lost
 645                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 646                         # Transaction is gone, like it or not
 647                         $this->mTrxLevel = 0;
 648                         wfDebug( "Connection lost, reconnecting...\n" );
 649                         if ( $this->ping() ) {
 650                                 wfDebug( "Reconnected\n" );
 651                                 $ret = $this->doQuery( $commentedSql );
 652                         } else {
 653                                 wfDebug( "Failed\n" );
 654                         }
 655                 }
 656
 657                 if ( false === $ret ) {
 658                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 659                 }
 660
 661                 if ( $wgProfiling ) {
 662                         wfProfileOut( $queryProf );
 663                         wfProfileOut( $totalProf );
 664                 }
 665                 return $ret;
 666         }
 667
 668         /**
 669          * The DBMS-dependent part of query()
 670          * @param string $sql SQL query.
 671          */
 672         function doQuery( $sql ) {
 673                 if( $this->bufferResults() ) {
 674                         $ret = mysql_query( $sql, $this->mConn );
 675                 } else {
 676                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 677                 }
 678                 return $ret;
 679         }
 680
 681         /**
 682          * @param $error
 683          * @param $errno
 684          * @param $sql
 685          * @param string $fname
 686          * @param bool $tempIgnore
 687          */
 688         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 689                 global $wgCommandLineMode;
 690                 # Ignore errors during error handling to avoid infinite recursion
 691                 $ignore = $this->ignoreErrors( true );
 692                 ++$this->mErrorCount;
 693
 694                 if( $ignore || $tempIgnore ) {
 695                         wfDebug("SQL ERROR (ignored): $error\n");
 696                         $this->ignoreErrors( $ignore );
 697                 } else {
 698                         $sql1line = str_replace( "\n", "\\n", $sql );
 699                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 700                         wfDebug("SQL ERROR: " . $error . "\n");
 701                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 702                 }
 703         }
 704
 705
 706         /**
 707          * Intended to be compatible with the PEAR::DB wrapper functions.
 708          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 709          *
 710          * ? = scalar value, quoted as necessary
 711          * ! = raw SQL bit (a function for instance)
 712          * & = filename; reads the file and inserts as a blob
 713          *     (we don't use this though...)
 714          */
 715         function prepare( $sql, $func = 'Database::prepare' ) {
 716                 /* MySQL doesn't support prepared statements (yet), so just
 717                    pack up the query for reference. We'll manually replace
 718                    the bits later. */
 719                 return array( 'query' => $sql, 'func' => $func );
 720         }
 721
 722         function freePrepared( $prepared ) {
 723                 /* No-op for MySQL */
 724         }
 725
 726         /**
 727          * Execute a prepared query with the various arguments
 728          * @param string $prepared the prepared sql
 729          * @param mixed $args Either an array here, or put scalars as varargs
 730          */
 731         function execute( $prepared, $args = null ) {
 732                 if( !is_array( $args ) ) {
 733                         # Pull the var args
 734                         $args = func_get_args();
 735                         array_shift( $args );
 736                 }
 737                 $sql = $this->fillPrepared( $prepared['query'], $args );
 738                 return $this->query( $sql, $prepared['func'] );
 739         }
 740
 741         /**
 742          * Prepare & execute an SQL statement, quoting and inserting arguments
 743          * in the appropriate places.
 744          * @param string $query
 745          * @param string $args ...
 746          */
 747         function safeQuery( $query, $args = null ) {
 748                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 749                 if( !is_array( $args ) ) {
 750                         # Pull the var args
 751                         $args = func_get_args();
 752                         array_shift( $args );
 753                 }
 754                 $retval = $this->execute( $prepared, $args );
 755                 $this->freePrepared( $prepared );
 756                 return $retval;
 757         }
 758
 759         /**
 760          * For faking prepared SQL statements on DBs that don't support
 761          * it directly.
 762          * @param string $preparedSql - a 'preparable' SQL statement
 763          * @param array $args - array of arguments to fill it with
 764          * @return string executable SQL
 765          */
 766         function fillPrepared( $preparedQuery, $args ) {
 767                 reset( $args );
 768                 $this->preparedArgs =& $args;
 769                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 770                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 771         }
 772
 773         /**
 774          * preg_callback func for fillPrepared()
 775          * The arguments should be in $this->preparedArgs and must not be touched
 776          * while we're doing this.
 777          *
 778          * @param array $matches
 779          * @return string
 780          * @private
 781          */
 782         function fillPreparedArg( $matches ) {
 783                 switch( $matches[1] ) {
 784                         case '\\?': return '?';
 785                         case '\\!': return '!';
 786                         case '\\&': return '&';
 787                 }
 788                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 789                 switch( $matches[1] ) {
 790                         case '?': return $this->addQuotes( $arg );
 791                         case '!': return $arg;
 792                         case '&':
 793                                 # return $this->addQuotes( file_get_contents( $arg ) );
 794                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 795                         default:
 796                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 797                 }
 798         }
 799
 800         /**#@+
 801          * @param mixed $res A SQL result
 802          */
 803         /**
 804          * Free a result object
 805          */
 806         function freeResult( $res ) {
 807                 if ( !@/**/mysql_free_result( $res ) ) {
 808                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 809                 }
 810         }
 811
 812         /**
 813          * Fetch the next row from the given result object, in object form
 814          */
 815         function fetchObject( $res ) {
 816                 @/**/$row = mysql_fetch_object( $res );
 817                 if( $this->lastErrno() ) {
 818                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 819                 }
 820                 return $row;
 821         }
 822
 823         /**
 824          * Fetch the next row from the given result object
 825          * Returns an array
 826          */
 827         function fetchRow( $res ) {
 828                 @/**/$row = mysql_fetch_array( $res );
 829                 if ( $this->lastErrno() ) {
 830                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 831                 }
 832                 return $row;
 833         }
 834
 835         /**
 836          * Get the number of rows in a result object
 837          */
 838         function numRows( $res ) {
 839                 @/**/$n = mysql_num_rows( $res );
 840                 if( $this->lastErrno() ) {
 841                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 842                 }
 843                 return $n;
 844         }
 845
 846         /**
 847          * Get the number of fields in a result object
 848          * See documentation for mysql_num_fields()
 849          */
 850         function numFields( $res ) { return mysql_num_fields( $res ); }
 851
 852         /**
 853          * Get a field name in a result object
 854          * See documentation for mysql_field_name():
 855          * http://www.php.net/mysql_field_name
 856          */
 857         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 858
 859         /**
 860          * Get the inserted value of an auto-increment row
 861          *
 862          * The value inserted should be fetched from nextSequenceValue()
 863          *
 864          * Example:
 865          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 866          * $dbw->insert('page',array('page_id' => $id));
 867          * $id = $dbw->insertId();
 868          */
 869         function insertId() { return mysql_insert_id( $this->mConn ); }
 870
 871         /**
 872          * Change the position of the cursor in a result object
 873          * See mysql_data_seek()
 874          */
 875         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 876
 877         /**
 878          * Get the last error number
 879          * See mysql_errno()
 880          */
 881         function lastErrno() {
 882                 if ( $this->mConn ) {
 883                         return mysql_errno( $this->mConn );
 884                 } else {
 885                         return mysql_errno();
 886                 }
 887         }
 888
 889         /**
 890          * Get a description of the last error
 891          * See mysql_error() for more details
 892          */
 893         function lastError() {
 894                 if ( $this->mConn ) {
 895                         # Even if it's non-zero, it can still be invalid
 896                         wfSuppressWarnings();
 897                         $error = mysql_error( $this->mConn );
 898                         if ( !$error ) {
 899                                 $error = mysql_error();
 900                         }
 901                         wfRestoreWarnings();
 902                 } else {
 903                         $error = mysql_error();
 904                 }
 905                 if( $error ) {
 906                         $error .= ' (' . $this->mServer . ')';
 907                 }
 908                 return $error;
 909         }
 910         /**
 911          * Get the number of rows affected by the last write query
 912          * See mysql_affected_rows() for more details
 913          */
 914         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 915         /**#@-*/ // end of template : @param $result
 916
 917         /**
 918          * Simple UPDATE wrapper
 919          * Usually aborts on failure
 920          * If errors are explicitly ignored, returns success
 921          *
 922          * This function exists for historical reasons, Database::update() has a more standard
 923          * calling convention and feature set
 924          */
 925         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 926         {
 927                 $table = $this->tableName( $table );
 928                 $sql = "UPDATE $table SET $var = '" .
 929                   $this->strencode( $value ) . "' WHERE ($cond)";
 930                 return (bool)$this->query( $sql, $fname );
 931         }
 932
 933         /**
 934          * Simple SELECT wrapper, returns a single field, input must be encoded
 935          * Usually aborts on failure
 936          * If errors are explicitly ignored, returns FALSE on failure
 937          */
 938         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 939                 if ( !is_array( $options ) ) {
 940                         $options = array( $options );
 941                 }
 942                 $options['LIMIT'] = 1;
 943
 944                 $res = $this->select( $table, $var, $cond, $fname, $options );
 945                 if ( $res === false || !$this->numRows( $res ) ) {
 946                         return false;
 947                 }
 948                 $row = $this->fetchRow( $res );
 949                 if ( $row !== false ) {
 950                         $this->freeResult( $res );
 951                         return $row[0];
 952                 } else {
 953                         return false;
 954                 }
 955         }
 956
 957         /**
 958          * Returns an optional USE INDEX clause to go after the table, and a
 959          * string to go at the end of the query
 960          *
 961          * @private
 962          *
 963          * @param array $options an associative array of options to be turned into
 964          *              an SQL query, valid keys are listed in the function.
 965          * @return array
 966          */
 967         function makeSelectOptions( $options ) {
 968                 $tailOpts = '';
 969                 $startOpts = '';
 970
 971                 $noKeyOptions = array();
 972                 foreach ( $options as $key => $option ) {
 973                         if ( is_numeric( $key ) ) {
 974                                 $noKeyOptions[$option] = true;
 975                         }
 976                 }
 977
 978                 if ( isset( $options['GROUP BY'] ) ) $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 979                 if ( isset( $options['ORDER BY'] ) ) $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 980
 981                 if (isset($options['LIMIT'])) {
 982                         $tailOpts .= $this->limitResult('', $options['LIMIT'],
 983                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 984                 }
 985
 986                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $tailOpts .= ' FOR UPDATE';
 987                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $tailOpts .= ' LOCK IN SHARE MODE';
 988                 if ( isset( $noKeyOptions['DISTINCT'] ) && isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 989
 990                 # Various MySQL extensions
 991                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 992                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 993                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 994                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 995                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 996                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 997                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 998                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 999
1000                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
1001                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1002                 } else {
1003                         $useIndex = '';
1004                 }
1005
1006                 return array( $startOpts, $useIndex, $tailOpts );
1007         }
1008
1009         /**
1010          * SELECT wrapper
1011          *
1012          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
1013          * @param mixed  $vars    Array or string, field name(s) to be retrieved
1014          * @param mixed  $conds   Array or string, condition(s) for WHERE
1015          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
1016          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1017          *                        see Database::makeSelectOptions code for list of supported stuff
1018          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
1019          */
1020         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
1021         {
1022                 if( is_array( $vars ) ) {
1023                         $vars = implode( ',', $vars );
1024                 }
1025                 if( !is_array( $options ) ) {
1026                         $options = array( $options );
1027                 }
1028                 if( is_array( $table ) ) {
1029                         if ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
1030                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
1031                         else
1032                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1033                 } elseif ($table!='') {
1034                         $from = ' FROM ' . $this->tableName( $table );
1035                 } else {
1036                         $from = '';
1037                 }
1038
1039                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $options );
1040
1041                 if( !empty( $conds ) ) {
1042                         if ( is_array( $conds ) ) {
1043                                 $conds = $this->makeList( $conds, LIST_AND );
1044                         }
1045                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $tailOpts";
1046                 } else {
1047                         $sql = "SELECT $startOpts $vars $from $useIndex $tailOpts";
1048                 }
1049
1050                 return $this->query( $sql, $fname );
1051         }
1052
1053         /**
1054          * Single row SELECT wrapper
1055          * Aborts or returns FALSE on error
1056          *
1057          * $vars: the selected variables
1058          * $conds: a condition map, terms are ANDed together.
1059          *   Items with numeric keys are taken to be literal conditions
1060          * Takes an array of selected variables, and a condition map, which is ANDed
1061          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1062          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1063          * $obj- >page_id is the ID of the Astronomy article
1064          *
1065          * @todo migrate documentation to phpdocumentor format
1066          */
1067         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
1068                 $options['LIMIT'] = 1;
1069                 $res = $this->select( $table, $vars, $conds, $fname, $options );
1070                 if ( $res === false )
1071                         return false;
1072                 if ( !$this->numRows($res) ) {
1073                         $this->freeResult($res);
1074                         return false;
1075                 }
1076                 $obj = $this->fetchObject( $res );
1077                 $this->freeResult( $res );
1078                 return $obj;
1079
1080         }
1081
1082         /**
1083          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1084          * It's only slightly flawed. Don't use for anything important.
1085          *
1086          * @param string $sql A SQL Query
1087          * @static
1088          */
1089         static function generalizeSQL( $sql ) {
1090                 # This does the same as the regexp below would do, but in such a way
1091                 # as to avoid crashing php on some large strings.
1092                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1093
1094                 $sql = str_replace ( "\\\\", '', $sql);
1095                 $sql = str_replace ( "\\'", '', $sql);
1096                 $sql = str_replace ( "\\\"", '', $sql);
1097                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1098                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1099
1100                 # All newlines, tabs, etc replaced by single space
1101                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1102
1103                 # All numbers => N
1104                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1105
1106                 return $sql;
1107         }
1108
1109         /**
1110          * Determines whether a field exists in a table
1111          * Usually aborts on failure
1112          * If errors are explicitly ignored, returns NULL on failure
1113          */
1114         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1115                 $table = $this->tableName( $table );
1116                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1117                 if ( !$res ) {
1118                         return NULL;
1119                 }
1120
1121                 $found = false;
1122
1123                 while ( $row = $this->fetchObject( $res ) ) {
1124                         if ( $row->Field == $field ) {
1125                                 $found = true;
1126                                 break;
1127                         }
1128                 }
1129                 return $found;
1130         }
1131
1132         /**
1133          * Determines whether an index exists
1134          * Usually aborts on failure
1135          * If errors are explicitly ignored, returns NULL on failure
1136          */
1137         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1138                 $info = $this->indexInfo( $table, $index, $fname );
1139                 if ( is_null( $info ) ) {
1140                         return NULL;
1141                 } else {
1142                         return $info !== false;
1143                 }
1144         }
1145
1146
1147         /**
1148          * Get information about an index into an object
1149          * Returns false if the index does not exist
1150          */
1151         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1152                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1153                 # SHOW INDEX should work for 3.x and up:
1154                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1155                 $table = $this->tableName( $table );
1156                 $sql = 'SHOW INDEX FROM '.$table;
1157                 $res = $this->query( $sql, $fname );
1158                 if ( !$res ) {
1159                         return NULL;
1160                 }
1161
1162                 $result = array();
1163                 while ( $row = $this->fetchObject( $res ) ) {
1164                         if ( $row->Key_name == $index ) {
1165                                 $result[] = $row;
1166                         }
1167                 }
1168                 $this->freeResult($res);
1169
1170                 return empty($result) ? false : $result;
1171         }
1172
1173         /**
1174          * Query whether a given table exists
1175          */
1176         function tableExists( $table ) {
1177                 $table = $this->tableName( $table );
1178                 $old = $this->ignoreErrors( true );
1179                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1180                 $this->ignoreErrors( $old );
1181                 if( $res ) {
1182                         $this->freeResult( $res );
1183                         return true;
1184                 } else {
1185                         return false;
1186                 }
1187         }
1188
1189         /**
1190          * mysql_fetch_field() wrapper
1191          * Returns false if the field doesn't exist
1192          *
1193          * @param $table
1194          * @param $field
1195          */
1196         function fieldInfo( $table, $field ) {
1197                 $table = $this->tableName( $table );
1198                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1199                 $n = mysql_num_fields( $res );
1200                 for( $i = 0; $i < $n; $i++ ) {
1201                         $meta = mysql_fetch_field( $res, $i );
1202                         if( $field == $meta->name ) {
1203                                 return $meta;
1204                         }
1205                 }
1206                 return false;
1207         }
1208
1209         /**
1210          * mysql_field_type() wrapper
1211          */
1212         function fieldType( $res, $index ) {
1213                 return mysql_field_type( $res, $index );
1214         }
1215
1216         /**
1217          * Determines if a given index is unique
1218          */
1219         function indexUnique( $table, $index ) {
1220                 $indexInfo = $this->indexInfo( $table, $index );
1221                 if ( !$indexInfo ) {
1222                         return NULL;
1223                 }
1224                 return !$indexInfo[0]->Non_unique;
1225         }
1226
1227         /**
1228          * INSERT wrapper, inserts an array into a table
1229          *
1230          * $a may be a single associative array, or an array of these with numeric keys, for
1231          * multi-row insert.
1232          *
1233          * Usually aborts on failure
1234          * If errors are explicitly ignored, returns success
1235          */
1236         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1237                 # No rows to insert, easy just return now
1238                 if ( !count( $a ) ) {
1239                         return true;
1240                 }
1241
1242                 $table = $this->tableName( $table );
1243                 if ( !is_array( $options ) ) {
1244                         $options = array( $options );
1245                 }
1246                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1247                         $multi = true;
1248                         $keys = array_keys( $a[0] );
1249                 } else {
1250                         $multi = false;
1251                         $keys = array_keys( $a );
1252                 }
1253
1254                 $sql = 'INSERT ' . implode( ' ', $options ) .
1255                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1256
1257                 if ( $multi ) {
1258                         $first = true;
1259                         foreach ( $a as $row ) {
1260                                 if ( $first ) {
1261                                         $first = false;
1262                                 } else {
1263                                         $sql .= ',';
1264                                 }
1265                                 $sql .= '(' . $this->makeList( $row ) . ')';
1266                         }
1267                 } else {
1268                         $sql .= '(' . $this->makeList( $a ) . ')';
1269                 }
1270                 return (bool)$this->query( $sql, $fname );
1271         }
1272
1273         /**
1274          * Make UPDATE options for the Database::update function
1275          *
1276          * @private
1277          * @param array $options The options passed to Database::update
1278          * @return string
1279          */
1280         function makeUpdateOptions( $options ) {
1281                 if( !is_array( $options ) ) {
1282                         $options = array( $options );
1283                 }
1284                 $opts = array();
1285                 if ( in_array( 'LOW_PRIORITY', $options ) )
1286                         $opts[] = $this->lowPriorityOption();
1287                 if ( in_array( 'IGNORE', $options ) )
1288                         $opts[] = 'IGNORE';
1289                 return implode(' ', $opts);
1290         }
1291
1292         /**
1293          * UPDATE wrapper, takes a condition array and a SET array
1294          *
1295          * @param string $table  The table to UPDATE
1296          * @param array  $values An array of values to SET
1297          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1298          * @param string $fname  The Class::Function calling this function
1299          *                       (for the log)
1300          * @param array  $options An array of UPDATE options, can be one or
1301          *                        more of IGNORE, LOW_PRIORITY
1302          */
1303         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1304                 $table = $this->tableName( $table );
1305                 $opts = $this->makeUpdateOptions( $options );
1306                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1307                 if ( $conds != '*' ) {
1308                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1309                 }
1310                 $this->query( $sql, $fname );
1311         }
1312
1313         /**
1314          * Makes an encoded list of strings from an array
1315          * $mode:
1316          *        LIST_COMMA         - comma separated, no field names
1317          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1318          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1319          *        LIST_SET           - comma separated with field names, like a SET clause
1320          *        LIST_NAMES         - comma separated field names
1321          */
1322         function makeList( $a, $mode = LIST_COMMA ) {
1323                 if ( !is_array( $a ) ) {
1324                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1325                 }
1326
1327                 $first = true;
1328                 $list = '';
1329                 foreach ( $a as $field => $value ) {
1330                         if ( !$first ) {
1331                                 if ( $mode == LIST_AND ) {
1332                                         $list .= ' AND ';
1333                                 } elseif($mode == LIST_OR) {
1334                                         $list .= ' OR ';
1335                                 } else {
1336                                         $list .= ',';
1337                                 }
1338                         } else {
1339                                 $first = false;
1340                         }
1341                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1342                                 $list .= "($value)";
1343                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1344                                 $list .= "$value";
1345                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array ($value) ) {
1346                                 $list .= $field." IN (".$this->makeList($value).") ";
1347                         } else {
1348                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1349                                         $list .= "$field = ";
1350                                 }
1351                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1352                         }
1353                 }
1354                 return $list;
1355         }
1356
1357         /**
1358          * Change the current database
1359          */
1360         function selectDB( $db ) {
1361                 $this->mDBname = $db;
1362                 return mysql_select_db( $db, $this->mConn );
1363         }
1364
1365         /**
1366          * Format a table name ready for use in constructing an SQL query
1367          *
1368          * This does two important things: it quotes table names which as necessary,
1369          * and it adds a table prefix if there is one.
1370          *
1371          * All functions of this object which require a table name call this function
1372          * themselves. Pass the canonical name to such functions. This is only needed
1373          * when calling query() directly.
1374          *
1375          * @param string $name database table name
1376          */
1377         function tableName( $name ) {
1378                 global $wgSharedDB;
1379                 # Skip quoted literals
1380                 if ( $name{0} != '`' ) {
1381                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1382                                 $name = "{$this->mTablePrefix}$name";
1383                         }
1384                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1385                                 $name = "`$wgSharedDB`.`$name`";
1386                         } else {
1387                                 # Standard quoting
1388                                 $name = "`$name`";
1389                         }
1390                 }
1391                 return $name;
1392         }
1393
1394         /**
1395          * Fetch a number of table names into an array
1396          * This is handy when you need to construct SQL for joins
1397          *
1398          * Example:
1399          * extract($dbr->tableNames('user','watchlist'));
1400          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1401          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1402          */
1403         public function tableNames() {
1404                 $inArray = func_get_args();
1405                 $retVal = array();
1406                 foreach ( $inArray as $name ) {
1407                         $retVal[$name] = $this->tableName( $name );
1408                 }
1409                 return $retVal;
1410         }
1411
1412         /**
1413          * @desc: Fetch a number of table names into an zero-indexed numerical array
1414          * This is handy when you need to construct SQL for joins
1415          *
1416          * Example:
1417          * list( $user, $watchlist ) = $dbr->tableNames('user','watchlist');
1418          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1419          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1420          */
1421         public function tableNamesN() {
1422                 $inArray = func_get_args();
1423                 $retVal = array();
1424                 foreach ( $inArray as $name ) {
1425                         $retVal[] = $this->tableName( $name );
1426                 }
1427                 return $retVal;
1428         }
1429
1430         /**
1431          * @private
1432          */
1433         function tableNamesWithUseIndex( $tables, $use_index ) {
1434                 $ret = array();
1435
1436                 foreach ( $tables as $table )
1437                         if ( @$use_index[$table] !== null )
1438                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1439                         else
1440                                 $ret[] = $this->tableName( $table );
1441
1442                 return implode( ',', $ret );
1443         }
1444
1445         /**
1446          * Wrapper for addslashes()
1447          * @param string $s String to be slashed.
1448          * @return string slashed string.
1449          */
1450         function strencode( $s ) {
1451                 return mysql_real_escape_string( $s, $this->mConn );
1452         }
1453
1454         /**
1455          * If it's a string, adds quotes and backslashes
1456          * Otherwise returns as-is
1457          */
1458         function addQuotes( $s ) {
1459                 if ( is_null( $s ) ) {
1460                         return 'NULL';
1461                 } else {
1462                         # This will also quote numeric values. This should be harmless,
1463                         # and protects against weird problems that occur when they really
1464                         # _are_ strings such as article titles and string->number->string
1465                         # conversion is not 1:1.
1466                         return "'" . $this->strencode( $s ) . "'";
1467                 }
1468         }
1469
1470         /**
1471          * Escape string for safe LIKE usage
1472          */
1473         function escapeLike( $s ) {
1474                 $s=$this->strencode( $s );
1475                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1476                 return $s;
1477         }
1478
1479         /**
1480          * Returns an appropriately quoted sequence value for inserting a new row.
1481          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1482          * subclass will return an integer, and save the value for insertId()
1483          */
1484         function nextSequenceValue( $seqName ) {
1485                 return NULL;
1486         }
1487
1488         /**
1489          * USE INDEX clause
1490          * PostgreSQL doesn't have them and returns ""
1491          */
1492         function useIndexClause( $index ) {
1493                 return "FORCE INDEX ($index)";
1494         }
1495
1496         /**
1497          * REPLACE query wrapper
1498          * PostgreSQL simulates this with a DELETE followed by INSERT
1499          * $row is the row to insert, an associative array
1500          * $uniqueIndexes is an array of indexes. Each element may be either a
1501          * field name or an array of field names
1502          *
1503          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1504          * However if you do this, you run the risk of encountering errors which wouldn't have
1505          * occurred in MySQL
1506          *
1507          * @todo migrate comment to phodocumentor format
1508          */
1509         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1510                 $table = $this->tableName( $table );
1511
1512                 # Single row case
1513                 if ( !is_array( reset( $rows ) ) ) {
1514                         $rows = array( $rows );
1515                 }
1516
1517                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1518                 $first = true;
1519                 foreach ( $rows as $row ) {
1520                         if ( $first ) {
1521                                 $first = false;
1522                         } else {
1523                                 $sql .= ',';
1524                         }
1525                         $sql .= '(' . $this->makeList( $row ) . ')';
1526                 }
1527                 return $this->query( $sql, $fname );
1528         }
1529
1530         /**
1531          * DELETE where the condition is a join
1532          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1533          *
1534          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1535          * join condition matches, set $conds='*'
1536          *
1537          * DO NOT put the join condition in $conds
1538          *
1539          * @param string $delTable The table to delete from.
1540          * @param string $joinTable The other table.
1541          * @param string $delVar The variable to join on, in the first table.
1542          * @param string $joinVar The variable to join on, in the second table.
1543          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1544          */
1545         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1546                 if ( !$conds ) {
1547                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1548                 }
1549
1550                 $delTable = $this->tableName( $delTable );
1551                 $joinTable = $this->tableName( $joinTable );
1552                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1553                 if ( $conds != '*' ) {
1554                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1555                 }
1556
1557                 return $this->query( $sql, $fname );
1558         }
1559
1560         /**
1561          * Returns the size of a text field, or -1 for "unlimited"
1562          */
1563         function textFieldSize( $table, $field ) {
1564                 $table = $this->tableName( $table );
1565                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1566                 $res = $this->query( $sql, 'Database::textFieldSize' );
1567                 $row = $this->fetchObject( $res );
1568                 $this->freeResult( $res );
1569
1570                 $m = array();
1571                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1572                         $size = $m[1];
1573                 } else {
1574                         $size = -1;
1575                 }
1576                 return $size;
1577         }
1578
1579         /**
1580          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1581          */
1582         function lowPriorityOption() {
1583                 return 'LOW_PRIORITY';
1584         }
1585
1586         /**
1587          * DELETE query wrapper
1588          *
1589          * Use $conds == "*" to delete all rows
1590          */
1591         function delete( $table, $conds, $fname = 'Database::delete' ) {
1592                 if ( !$conds ) {
1593                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1594                 }
1595                 $table = $this->tableName( $table );
1596                 $sql = "DELETE FROM $table";
1597                 if ( $conds != '*' ) {
1598                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1599                 }
1600                 return $this->query( $sql, $fname );
1601         }
1602
1603         /**
1604          * INSERT SELECT wrapper
1605          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1606          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1607          * $conds may be "*" to copy the whole table
1608          * srcTable may be an array of tables.
1609          */
1610         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1611                 $insertOptions = array(), $selectOptions = array() )
1612         {
1613                 $destTable = $this->tableName( $destTable );
1614                 if ( is_array( $insertOptions ) ) {
1615                         $insertOptions = implode( ' ', $insertOptions );
1616                 }
1617                 if( !is_array( $selectOptions ) ) {
1618                         $selectOptions = array( $selectOptions );
1619                 }
1620                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1621                 if( is_array( $srcTable ) ) {
1622                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1623                 } else {
1624                         $srcTable = $this->tableName( $srcTable );
1625                 }
1626                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1627                         " SELECT $startOpts " . implode( ',', $varMap ) .
1628                         " FROM $srcTable $useIndex ";
1629                 if ( $conds != '*' ) {
1630                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1631                 }
1632                 $sql .= " $tailOpts";
1633                 return $this->query( $sql, $fname );
1634         }
1635
1636         /**
1637          * Construct a LIMIT query with optional offset
1638          * This is used for query pages
1639          * $sql string SQL query we will append the limit too
1640          * $limit integer the SQL limit
1641          * $offset integer the SQL offset (default false)
1642          */
1643         function limitResult($sql, $limit, $offset=false) {
1644                 if( !is_numeric($limit) ) {
1645                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1646                 }
1647                 return " $sql LIMIT "
1648                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1649                                 . "{$limit} ";
1650         }
1651         function limitResultForUpdate($sql, $num) {
1652                 return $this->limitResult($sql, $num, 0);
1653         }
1654
1655         /**
1656          * Returns an SQL expression for a simple conditional.
1657          * Uses IF on MySQL.
1658          *
1659          * @param string $cond SQL expression which will result in a boolean value
1660          * @param string $trueVal SQL expression to return if true
1661          * @param string $falseVal SQL expression to return if false
1662          * @return string SQL fragment
1663          */
1664         function conditional( $cond, $trueVal, $falseVal ) {
1665                 return " IF($cond, $trueVal, $falseVal) ";
1666         }
1667
1668         /**
1669          * Determines if the last failure was due to a deadlock
1670          */
1671         function wasDeadlock() {
1672                 return $this->lastErrno() == 1213;
1673         }
1674
1675         /**
1676          * Perform a deadlock-prone transaction.
1677          *
1678          * This function invokes a callback function to perform a set of write
1679          * queries. If a deadlock occurs during the processing, the transaction
1680          * will be rolled back and the callback function will be called again.
1681          *
1682          * Usage:
1683          *   $dbw->deadlockLoop( callback, ... );
1684          *
1685          * Extra arguments are passed through to the specified callback function.
1686          *
1687          * Returns whatever the callback function returned on its successful,
1688          * iteration, or false on error, for example if the retry limit was
1689          * reached.
1690          */
1691         function deadlockLoop() {
1692                 $myFname = 'Database::deadlockLoop';
1693
1694                 $this->begin();
1695                 $args = func_get_args();
1696                 $function = array_shift( $args );
1697                 $oldIgnore = $this->ignoreErrors( true );
1698                 $tries = DEADLOCK_TRIES;
1699                 if ( is_array( $function ) ) {
1700                         $fname = $function[0];
1701                 } else {
1702                         $fname = $function;
1703                 }
1704                 do {
1705                         $retVal = call_user_func_array( $function, $args );
1706                         $error = $this->lastError();
1707                         $errno = $this->lastErrno();
1708                         $sql = $this->lastQuery();
1709
1710                         if ( $errno ) {
1711                                 if ( $this->wasDeadlock() ) {
1712                                         # Retry
1713                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1714                                 } else {
1715                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1716                                 }
1717                         }
1718                 } while( $this->wasDeadlock() && --$tries > 0 );
1719                 $this->ignoreErrors( $oldIgnore );
1720                 if ( $tries <= 0 ) {
1721                         $this->query( 'ROLLBACK', $myFname );
1722                         $this->reportQueryError( $error, $errno, $sql, $fname );
1723                         return false;
1724                 } else {
1725                         $this->query( 'COMMIT', $myFname );
1726                         return $retVal;
1727                 }
1728         }
1729
1730         /**
1731          * Do a SELECT MASTER_POS_WAIT()
1732          *
1733          * @param string $file the binlog file
1734          * @param string $pos the binlog position
1735          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1736          */
1737         function masterPosWait( $file, $pos, $timeout ) {
1738                 $fname = 'Database::masterPosWait';
1739                 wfProfileIn( $fname );
1740
1741
1742                 # Commit any open transactions
1743                 $this->immediateCommit();
1744
1745                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1746                 $encFile = $this->strencode( $file );
1747                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1748                 $res = $this->doQuery( $sql );
1749                 if ( $res && $row = $this->fetchRow( $res ) ) {
1750                         $this->freeResult( $res );
1751                         wfProfileOut( $fname );
1752                         return $row[0];
1753                 } else {
1754                         wfProfileOut( $fname );
1755                         return false;
1756                 }
1757         }
1758
1759         /**
1760          * Get the position of the master from SHOW SLAVE STATUS
1761          */
1762         function getSlavePos() {
1763                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1764                 $row = $this->fetchObject( $res );
1765                 if ( $row ) {
1766                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1767                 } else {
1768                         return array( false, false );
1769                 }
1770         }
1771
1772         /**
1773          * Get the position of the master from SHOW MASTER STATUS
1774          */
1775         function getMasterPos() {
1776                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1777                 $row = $this->fetchObject( $res );
1778                 if ( $row ) {
1779                         return array( $row->File, $row->Position );
1780                 } else {
1781                         return array( false, false );
1782                 }
1783         }
1784
1785         /**
1786          * Begin a transaction, committing any previously open transaction
1787          */
1788         function begin( $fname = 'Database::begin' ) {
1789                 $this->query( 'BEGIN', $fname );
1790                 $this->mTrxLevel = 1;
1791         }
1792
1793         /**
1794          * End a transaction
1795          */
1796         function commit( $fname = 'Database::commit' ) {
1797                 $this->query( 'COMMIT', $fname );
1798                 $this->mTrxLevel = 0;
1799         }
1800
1801         /**
1802          * Rollback a transaction
1803          */
1804         function rollback( $fname = 'Database::rollback' ) {
1805                 $this->query( 'ROLLBACK', $fname );
1806                 $this->mTrxLevel = 0;
1807         }
1808
1809         /**
1810          * Begin a transaction, committing any previously open transaction
1811          * @deprecated use begin()
1812          */
1813         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1814                 $this->begin();
1815         }
1816
1817         /**
1818          * Commit transaction, if one is open
1819          * @deprecated use commit()
1820          */
1821         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1822                 $this->commit();
1823         }
1824
1825         /**
1826          * Return MW-style timestamp used for MySQL schema
1827          */
1828         function timestamp( $ts=0 ) {
1829                 return wfTimestamp(TS_MW,$ts);
1830         }
1831
1832         /**
1833          * Local database timestamp format or null
1834          */
1835         function timestampOrNull( $ts = null ) {
1836                 if( is_null( $ts ) ) {
1837                         return null;
1838                 } else {
1839                         return $this->timestamp( $ts );
1840                 }
1841         }
1842
1843         /**
1844          * @todo document
1845          */
1846         function resultObject( $result ) {
1847                 if( empty( $result ) ) {
1848                         return NULL;
1849                 } else {
1850                         return new ResultWrapper( $this, $result );
1851                 }
1852         }
1853
1854         /**
1855          * Return aggregated value alias
1856          */
1857         function aggregateValue ($valuedata,$valuename='value') {
1858                 return $valuename;
1859         }
1860
1861         /**
1862          * @return string wikitext of a link to the server software's web site
1863          */
1864         function getSoftwareLink() {
1865                 return "[http://www.mysql.com/ MySQL]";
1866         }
1867
1868         /**
1869          * @return string Version information from the database
1870          */
1871         function getServerVersion() {
1872                 return mysql_get_server_info( $this->mConn );
1873         }
1874
1875         /**
1876          * Ping the server and try to reconnect if it there is no connection
1877          */
1878         function ping() {
1879                 if( function_exists( 'mysql_ping' ) ) {
1880                         return mysql_ping( $this->mConn );
1881                 } else {
1882                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1883                         return true;
1884                 }
1885         }
1886
1887         /**
1888          * Get slave lag.
1889          * At the moment, this will only work if the DB user has the PROCESS privilege
1890          */
1891         function getLag() {
1892                 $res = $this->query( 'SHOW PROCESSLIST' );
1893                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1894                 # dubious, but unfortunately there's no easy rigorous way
1895                 while ( $row = $this->fetchObject( $res ) ) {
1896                         /* This should work for most situations - when default db
1897                          * for thread is not specified, it had no events executed,
1898                          * and therefore it doesn't know yet how lagged it is.
1899                          *
1900                          * Relay log I/O thread does not select databases.
1901                          */
1902                         if ( $row->User == 'system user' &&
1903                                 $row->State != 'Waiting for master to send event' &&
1904                                 $row->State != 'Connecting to master' &&
1905                                 $row->State != 'Queueing master event to the relay log' &&
1906                                 $row->State != 'Waiting for master update' &&
1907                                 $row->State != 'Requesting binlog dump'
1908                                 ) {
1909                                 # This is it, return the time (except -ve)
1910                                 if ( $row->Time > 0x7fffffff ) {
1911                                         return false;
1912                                 } else {
1913                                         return $row->Time;
1914                                 }
1915                         }
1916                 }
1917                 return false;
1918         }
1919
1920         /**
1921          * Get status information from SHOW STATUS in an associative array
1922          */
1923         function getStatus($which="%") {
1924                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1925                 $status = array();
1926                 while ( $row = $this->fetchObject( $res ) ) {
1927                         $status[$row->Variable_name] = $row->Value;
1928                 }
1929                 return $status;
1930         }
1931
1932         /**
1933          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1934          */
1935         function maxListLen() {
1936                 return 0;
1937         }
1938
1939         function encodeBlob($b) {
1940                 return $b;
1941         }
1942
1943         function decodeBlob($b) {
1944                 return $b;
1945         }
1946
1947         /**
1948          * Read and execute SQL commands from a file.
1949          * Returns true on success, error string on failure
1950          */
1951         function sourceFile( $filename ) {
1952                 $fp = fopen( $filename, 'r' );
1953                 if ( false === $fp ) {
1954                         return "Could not open \"{$filename}\".\n";
1955                 }
1956
1957                 $cmd = "";
1958                 $done = false;
1959                 $dollarquote = false;
1960
1961                 while ( ! feof( $fp ) ) {
1962                         $line = trim( fgets( $fp, 1024 ) );
1963                         $sl = strlen( $line ) - 1;
1964
1965                         if ( $sl < 0 ) { continue; }
1966                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
1967
1968                         ## Allow dollar quoting for function declarations
1969                         if (substr($line,0,4) == '$mw$') {
1970                                 if ($dollarquote) {
1971                                         $dollarquote = false;
1972                                         $done = true;
1973                                 }
1974                                 else {
1975                                         $dollarquote = true;
1976                                 }
1977                         }
1978                         else if (!$dollarquote) {
1979                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
1980                                         $done = true;
1981                                         $line = substr( $line, 0, $sl );
1982                                 }
1983                         }
1984
1985                         if ( '' != $cmd ) { $cmd .= ' '; }
1986                         $cmd .= "$line\n";
1987
1988                         if ( $done ) {
1989                                 $cmd = str_replace(';;', ";", $cmd);
1990                                 $cmd = $this->replaceVars( $cmd );
1991                                 $res = $this->query( $cmd, 'dbsource', true );
1992
1993                                 if ( false === $res ) {
1994                                         $err = $this->lastError();
1995                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
1996                                 }
1997
1998                                 $cmd = '';
1999                                 $done = false;
2000                         }
2001                 }
2002                 fclose( $fp );
2003                 return true;
2004         }
2005
2006         /**
2007          * Replace variables in sourced SQL
2008          */
2009         protected function replaceVars( $ins ) {
2010                 $varnames = array(
2011                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2012                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2013                         'wgDBadminuser', 'wgDBadminpassword',
2014                 );
2015
2016                 // Ordinary variables
2017                 foreach ( $varnames as $var ) {
2018                         if( isset( $GLOBALS[$var] ) ) {
2019                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2020                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2021                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2022                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2023                         }
2024                 }
2025
2026                 // Table prefixes
2027                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
2028                         array( &$this, 'tableNameCallback' ), $ins );
2029                 return $ins;
2030         }
2031
2032         /**
2033          * Table name callback
2034          * @private
2035          */
2036         protected function tableNameCallback( $matches ) {
2037                 return $this->tableName( $matches[1] );
2038         }
2039
2040 }
2041
2042 /**
2043  * Database abstraction object for mySQL
2044  * Inherit all methods and properties of Database::Database()
2045  *
2046  * @package MediaWiki
2047  * @see Database
2048  */
2049 class DatabaseMysql extends Database {
2050         # Inherit all
2051 }
2052
2053
2054 /**
2055  * Result wrapper for grabbing data queried by someone else
2056  *
2057  * @package MediaWiki
2058  */
2059 class ResultWrapper {
2060         var $db, $result;
2061
2062         /**
2063          * @todo document
2064          */
2065         function ResultWrapper( &$database, $result ) {
2066                 $this->db =& $database;
2067                 $this->result =& $result;
2068         }
2069
2070         /**
2071          * @todo document
2072          */
2073         function numRows() {
2074                 return $this->db->numRows( $this->result );
2075         }
2076
2077         /**
2078          * @todo document
2079          */
2080         function fetchObject() {
2081                 return $this->db->fetchObject( $this->result );
2082         }
2083
2084         /**
2085          * @todo document
2086          */
2087         function fetchRow() {
2088                 return $this->db->fetchRow( $this->result );
2089         }
2090
2091         /**
2092          * @todo document
2093          */
2094         function free() {
2095                 $this->db->freeResult( $this->result );
2096                 unset( $this->result );
2097                 unset( $this->db );
2098         }
2099
2100         function seek( $row ) {
2101                 $this->db->dataSeek( $this->result, $row );
2102         }
2103
2104 }
2105
2106 ?>