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