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