includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  */
   6
   7 /** Number of times to re-try an operation in case of deadlock */
   8 define( 'DEADLOCK_TRIES', 4 );
   9 /** Minimum time to wait before retry, in microseconds */
  10 define( 'DEADLOCK_DELAY_MIN', 500000 );
  11 /** Maximum time to wait before retry */
  12 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  13
  14 /**
  15  * Database abstraction object
  16  * @addtogroup Database
  17  */
  18 class Database {
  19
  20 #------------------------------------------------------------------------------
  21 # Variables
  22 #------------------------------------------------------------------------------
  23
  24         protected $mLastQuery = '';
  25
  26         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  27         protected $mOut, $mOpened = false;
  28
  29         protected $mFailFunction;
  30         protected $mTablePrefix;
  31         protected $mFlags;
  32         protected $mTrxLevel = 0;
  33         protected $mErrorCount = 0;
  34         protected $mLBInfo = array();
  35         protected $mFakeSlaveLag = null, $mFakeMaster = false;
  36
  37 #------------------------------------------------------------------------------
  38 # Accessors
  39 #------------------------------------------------------------------------------
  40         # These optionally set a variable and return the previous state
  41
  42         /**
  43          * Fail function, takes a Database as a parameter
  44          * Set to false for default, 1 for ignore errors
  45          */
  46         function failFunction( $function = NULL ) {
  47                 return wfSetVar( $this->mFailFunction, $function );
  48         }
  49
  50         /**
  51          * Output page, used for reporting errors
  52          * FALSE means discard output
  53          */
  54         function setOutputPage( $out ) {
  55                 $this->mOut = $out;
  56         }
  57
  58         /**
  59          * Boolean, controls output of large amounts of debug information
  60          */
  61         function debug( $debug = NULL ) {
  62                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  63         }
  64
  65         /**
  66          * Turns buffering of SQL result sets on (true) or off (false).
  67          * Default is "on" and it should not be changed without good reasons.
  68          */
  69         function bufferResults( $buffer = NULL ) {
  70                 if ( is_null( $buffer ) ) {
  71                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  72                 } else {
  73                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  74                 }
  75         }
  76
  77         /**
  78          * Turns on (false) or off (true) the automatic generation and sending
  79          * of a "we're sorry, but there has been a database error" page on
  80          * database errors. Default is on (false). When turned off, the
  81          * code should use lastErrno() and lastError() to handle the
  82          * situation as appropriate.
  83          */
  84         function ignoreErrors( $ignoreErrors = NULL ) {
  85                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  86         }
  87
  88         /**
  89          * The current depth of nested transactions
  90          * @param $level Integer: , default NULL.
  91          */
  92         function trxLevel( $level = NULL ) {
  93                 return wfSetVar( $this->mTrxLevel, $level );
  94         }
  95
  96         /**
  97          * Number of errors logged, only useful when errors are ignored
  98          */
  99         function errorCount( $count = NULL ) {
 100                 return wfSetVar( $this->mErrorCount, $count );
 101         }
 102
 103         function tablePrefix( $prefix = null ) {
 104                 return wfSetVar( $this->mTablePrefix, $prefix );
 105         }
 106
 107         /**
 108          * Properties passed down from the server info array of the load balancer
 109          */
 110         function getLBInfo( $name = NULL ) {
 111                 if ( is_null( $name ) ) {
 112                         return $this->mLBInfo;
 113                 } else {
 114                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 115                                 return $this->mLBInfo[$name];
 116                         } else {
 117                                 return NULL;
 118                         }
 119                 }
 120         }
 121
 122         function setLBInfo( $name, $value = NULL ) {
 123                 if ( is_null( $value ) ) {
 124                         $this->mLBInfo = $name;
 125                 } else {
 126                         $this->mLBInfo[$name] = $value;
 127                 }
 128         }
 129
 130         /**
 131          * Set lag time in seconds for a fake slave
 132          */
 133         function setFakeSlaveLag( $lag ) {
 134                 $this->mFakeSlaveLag = $lag;
 135         }
 136
 137         /**
 138          * Make this connection a fake master
 139          */
 140         function setFakeMaster( $enabled = true ) {
 141                 $this->mFakeMaster = $enabled;
 142         }
 143
 144         /**
 145          * Returns true if this database supports (and uses) cascading deletes
 146          */
 147         function cascadingDeletes() {
 148                 return false;
 149         }
 150
 151         /**
 152          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 153          */
 154         function cleanupTriggers() {
 155                 return false;
 156         }
 157
 158         /**
 159          * Returns true if this database is strict about what can be put into an IP field.
 160          * Specifically, it uses a NULL value instead of an empty string.
 161          */
 162         function strictIPs() {
 163                 return false;
 164         }
 165
 166         /**
 167          * Returns true if this database uses timestamps rather than integers
 168         */
 169         function realTimestamps() {
 170                 return false;
 171         }
 172
 173         /**
 174          * Returns true if this database does an implicit sort when doing GROUP BY
 175          */
 176         function implicitGroupby() {
 177                 return true;
 178         }
 179
 180         /**
 181          * Returns true if this database does an implicit order by when the column has an index
 182          * For example: SELECT page_title FROM page LIMIT 1
 183          */
 184         function implicitOrderby() {
 185                 return true;
 186         }
 187
 188         /**
 189          * Returns true if this database can do a native search on IP columns
 190          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 191          */
 192         function searchableIPs() {
 193                 return false;
 194         }
 195
 196         /**
 197          * Returns true if this database can use functional indexes
 198          */
 199         function functionalIndexes() {
 200                 return false;
 201         }
 202
 203         /**#@+
 204          * Get function
 205          */
 206         function lastQuery() { return $this->mLastQuery; }
 207         function isOpen() { return $this->mOpened; }
 208         /**#@-*/
 209
 210         function setFlag( $flag ) {
 211                 $this->mFlags |= $flag;
 212         }
 213
 214         function clearFlag( $flag ) {
 215                 $this->mFlags &= ~$flag;
 216         }
 217
 218         function getFlag( $flag ) {
 219                 return !!($this->mFlags & $flag);
 220         }
 221
 222         /**
 223          * General read-only accessor
 224          */
 225         function getProperty( $name ) {
 226                 return $this->$name;
 227         }
 228
 229 #------------------------------------------------------------------------------
 230 # Other functions
 231 #------------------------------------------------------------------------------
 232
 233         /**@{{
 234          * Constructor.
 235          * @param string $server database server host
 236          * @param string $user database user name
 237          * @param string $password database user password
 238          * @param string $dbname database name
 239          * @param failFunction
 240          * @param $flags
 241          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 242          */
 243         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 244                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 245
 246                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 247                 # Can't get a reference if it hasn't been set yet
 248                 if ( !isset( $wgOut ) ) {
 249                         $wgOut = NULL;
 250                 }
 251                 $this->mOut =& $wgOut;
 252
 253                 $this->mFailFunction = $failFunction;
 254                 $this->mFlags = $flags;
 255
 256                 if ( $this->mFlags & DBO_DEFAULT ) {
 257                         if ( $wgCommandLineMode ) {
 258                                 $this->mFlags &= ~DBO_TRX;
 259                         } else {
 260                                 $this->mFlags |= DBO_TRX;
 261                         }
 262                 }
 263
 264                 /*
 265                 // Faster read-only access
 266                 if ( wfReadOnly() ) {
 267                         $this->mFlags |= DBO_PERSISTENT;
 268                         $this->mFlags &= ~DBO_TRX;
 269                 }*/
 270
 271                 /** Get the default table prefix*/
 272                 if ( $tablePrefix == 'get from global' ) {
 273                         $this->mTablePrefix = $wgDBprefix;
 274                 } else {
 275                         $this->mTablePrefix = $tablePrefix;
 276                 }
 277
 278                 if ( $server ) {
 279                         $this->open( $server, $user, $password, $dbName );
 280                 }
 281         }
 282
 283         /**
 284          * @static
 285          * @param failFunction
 286          * @param $flags
 287          */
 288         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 289         {
 290                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 291         }
 292
 293         /**
 294          * Usually aborts on failure
 295          * If the failFunction is set to a non-zero integer, returns success
 296          */
 297         function open( $server, $user, $password, $dbName ) {
 298                 global $wguname, $wgAllDBsAreLocalhost;
 299                 wfProfileIn( __METHOD__ );
 300
 301                 # Test for missing mysql.so
 302                 # First try to load it
 303                 if (!@extension_loaded('mysql')) {
 304                         @dl('mysql.so');
 305                 }
 306
 307                 # Fail now
 308                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 309                 if ( !function_exists( 'mysql_connect' ) ) {
 310                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 311                 }
 312
 313                 # Debugging hack -- fake cluster
 314                 if ( $wgAllDBsAreLocalhost ) {
 315                         $realServer = 'localhost';
 316                 } else {
 317                         $realServer = $server;
 318                 }
 319                 $this->close();
 320                 $this->mServer = $server;
 321                 $this->mUser = $user;
 322                 $this->mPassword = $password;
 323                 $this->mDBname = $dbName;
 324
 325                 $success = false;
 326
 327                 wfProfileIn("dbconnect-$server");
 328
 329                 # Try to connect up to three times
 330                 # The kernel's default SYN retransmission period is far too slow for us,
 331                 # so we use a short timeout plus a manual retry.
 332                 $this->mConn = false;
 333                 $max = 3;
 334                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 335                         if ( $i > 1 ) {
 336                                 usleep( 1000 );
 337                         }
 338                         if ( $this->mFlags & DBO_PERSISTENT ) {
 339                                 @/**/$this->mConn = mysql_pconnect( $realServer, $user, $password );
 340                         } else {
 341                                 # Create a new connection...
 342                                 @/**/$this->mConn = mysql_connect( $realServer, $user, $password, true );
 343                         }
 344                         if ($this->mConn === false) {
 345                                 #$iplus = $i + 1;
 346                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 347                         }
 348                 }
 349
 350                 wfProfileOut("dbconnect-$server");
 351
 352                 if ( $dbName != '' ) {
 353                         if ( $this->mConn !== false ) {
 354                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 355                                 if ( !$success ) {
 356                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 357                                                 "from client host {$wguname['nodename']}\n";
 358                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 359                                         wfDebug( $error );
 360                                 }
 361                         } else {
 362                                 wfDebug( "DB connection error\n" );
 363                                 wfDebug( "Server: $server, User: $user, Password: " .
 364                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 365                                 $success = false;
 366                         }
 367                 } else {
 368                         # Delay USE query
 369                         $success = (bool)$this->mConn;
 370                 }
 371
 372                 if ( $success ) {
 373                         $version = $this->getServerVersion();
 374                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 375                                 // Tell the server we're communicating with it in UTF-8.
 376                                 // This may engage various charset conversions.
 377                                 global $wgDBmysql5;
 378                                 if( $wgDBmysql5 ) {
 379                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 380                                 }
 381                                 // Turn off strict mode
 382                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 383                         }
 384
 385                         // Turn off strict mode if it is on
 386                 } else {
 387                         $this->reportConnectionError();
 388                 }
 389
 390                 $this->mOpened = $success;
 391                 wfProfileOut( __METHOD__ );
 392                 return $success;
 393         }
 394         /**@}}*/
 395
 396         /**
 397          * Closes a database connection.
 398          * if it is open : commits any open transactions
 399          *
 400          * @return bool operation success. true if already closed.
 401          */
 402         function close()
 403         {
 404                 $this->mOpened = false;
 405                 if ( $this->mConn ) {
 406                         if ( $this->trxLevel() ) {
 407                                 $this->immediateCommit();
 408                         }
 409                         return mysql_close( $this->mConn );
 410                 } else {
 411                         return true;
 412                 }
 413         }
 414
 415         /**
 416          * @param string $error fallback error message, used if none is given by MySQL
 417          */
 418         function reportConnectionError( $error = 'Unknown error' ) {
 419                 $myError = $this->lastError();
 420                 if ( $myError ) {
 421                         $error = $myError;
 422                 }
 423
 424                 if ( $this->mFailFunction ) {
 425                         # Legacy error handling method
 426                         if ( !is_int( $this->mFailFunction ) ) {
 427                                 $ff = $this->mFailFunction;
 428                                 $ff( $this, $error );
 429                         }
 430                 } else {
 431                         # New method
 432                         wfLogDBError( "Connection error: $error\n" );
 433                         throw new DBConnectionError( $this, $error );
 434                 }
 435         }
 436
 437         /**
 438          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 439          *
 440          * @param  $sql        String: SQL query
 441          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 442          *     comment (you can use __METHOD__ or add some extra info)
 443          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 444          *     maybe best to catch the exception instead?
 445          * @return true for a successful write query, ResultWrapper object for a successful read query,
 446          *     or false on failure if $tempIgnore set
 447          * @throws DBQueryError Thrown when the database returns an error of any kind
 448          */
 449         public function query( $sql, $fname = '', $tempIgnore = false ) {
 450                 global $wgProfiler;
 451
 452                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 453                 if ( isset( $wgProfiler ) ) {
 454                         # generalizeSQL will probably cut down the query to reasonable
 455                         # logging size most of the time. The substr is really just a sanity check.
 456
 457                         # Who's been wasting my precious column space? -- TS
 458                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 459
 460                         if ( $isMaster ) {
 461                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 462                                 $totalProf = 'Database::query-master';
 463                         } else {
 464                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 465                                 $totalProf = 'Database::query';
 466                         }
 467                         wfProfileIn( $totalProf );
 468                         wfProfileIn( $queryProf );
 469                 }
 470
 471                 $this->mLastQuery = $sql;
 472
 473                 # Add a comment for easy SHOW PROCESSLIST interpretation
 474                 #if ( $fname ) {
 475                         global $wgUser;
 476                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 477                                 $userName = $wgUser->getName();
 478                                 if ( mb_strlen( $userName ) > 15 ) {
 479                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 480                                 }
 481                                 $userName = str_replace( '/', '', $userName );
 482                         } else {
 483                                 $userName = '';
 484                         }
 485                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 486                 #} else {
 487                 #       $commentedSql = $sql;
 488                 #}
 489
 490                 # If DBO_TRX is set, start a transaction
 491                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 492                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 493                         // avoid establishing transactions for SHOW and SET statements too -
 494                         // that would delay transaction initializations to once connection
 495                         // is really used by application
 496                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 497                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 498                                 $this->begin();
 499                 }
 500
 501                 if ( $this->debug() ) {
 502                         $sqlx = substr( $commentedSql, 0, 500 );
 503                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 504                         if ( $isMaster ) {
 505                                 wfDebug( "SQL-master: $sqlx\n" );
 506                         } else {
 507                                 wfDebug( "SQL: $sqlx\n" );
 508                         }
 509                 }
 510
 511                 # Do the query and handle errors
 512                 $ret = $this->doQuery( $commentedSql );
 513
 514                 # Try reconnecting if the connection was lost
 515                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 516                         # Transaction is gone, like it or not
 517                         $this->mTrxLevel = 0;
 518                         wfDebug( "Connection lost, reconnecting...\n" );
 519                         if ( $this->ping() ) {
 520                                 wfDebug( "Reconnected\n" );
 521                                 $sqlx = substr( $commentedSql, 0, 500 );
 522                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 523                                 global $wgRequestTime;
 524                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 525                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 526                                 $ret = $this->doQuery( $commentedSql );
 527                         } else {
 528                                 wfDebug( "Failed\n" );
 529                         }
 530                 }
 531
 532                 if ( false === $ret ) {
 533                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 534                 }
 535
 536                 if ( isset( $wgProfiler ) ) {
 537                         wfProfileOut( $queryProf );
 538                         wfProfileOut( $totalProf );
 539                 }
 540                 return $this->resultObject( $ret );
 541         }
 542
 543         /**
 544          * The DBMS-dependent part of query()
 545          * @param  $sql String: SQL query.
 546          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 547          * @access private
 548          */
 549         /*private*/ function doQuery( $sql ) {
 550                 if( $this->bufferResults() ) {
 551                         $ret = mysql_query( $sql, $this->mConn );
 552                 } else {
 553                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 554                 }
 555                 return $ret;
 556         }
 557
 558         /**
 559          * @param $error
 560          * @param $errno
 561          * @param $sql
 562          * @param string $fname
 563          * @param bool $tempIgnore
 564          */
 565         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 566                 global $wgCommandLineMode;
 567                 # Ignore errors during error handling to avoid infinite recursion
 568                 $ignore = $this->ignoreErrors( true );
 569                 ++$this->mErrorCount;
 570
 571                 if( $ignore || $tempIgnore ) {
 572                         wfDebug("SQL ERROR (ignored): $error\n");
 573                         $this->ignoreErrors( $ignore );
 574                 } else {
 575                         $sql1line = str_replace( "\n", "\\n", $sql );
 576                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 577                         wfDebug("SQL ERROR: " . $error . "\n");
 578                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 579                 }
 580         }
 581
 582
 583         /**
 584          * Intended to be compatible with the PEAR::DB wrapper functions.
 585          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 586          *
 587          * ? = scalar value, quoted as necessary
 588          * ! = raw SQL bit (a function for instance)
 589          * & = filename; reads the file and inserts as a blob
 590          *     (we don't use this though...)
 591          */
 592         function prepare( $sql, $func = 'Database::prepare' ) {
 593                 /* MySQL doesn't support prepared statements (yet), so just
 594                    pack up the query for reference. We'll manually replace
 595                    the bits later. */
 596                 return array( 'query' => $sql, 'func' => $func );
 597         }
 598
 599         function freePrepared( $prepared ) {
 600                 /* No-op for MySQL */
 601         }
 602
 603         /**
 604          * Execute a prepared query with the various arguments
 605          * @param string $prepared the prepared sql
 606          * @param mixed $args Either an array here, or put scalars as varargs
 607          */
 608         function execute( $prepared, $args = null ) {
 609                 if( !is_array( $args ) ) {
 610                         # Pull the var args
 611                         $args = func_get_args();
 612                         array_shift( $args );
 613                 }
 614                 $sql = $this->fillPrepared( $prepared['query'], $args );
 615                 return $this->query( $sql, $prepared['func'] );
 616         }
 617
 618         /**
 619          * Prepare & execute an SQL statement, quoting and inserting arguments
 620          * in the appropriate places.
 621          * @param string $query
 622          * @param string $args ...
 623          */
 624         function safeQuery( $query, $args = null ) {
 625                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 626                 if( !is_array( $args ) ) {
 627                         # Pull the var args
 628                         $args = func_get_args();
 629                         array_shift( $args );
 630                 }
 631                 $retval = $this->execute( $prepared, $args );
 632                 $this->freePrepared( $prepared );
 633                 return $retval;
 634         }
 635
 636         /**
 637          * For faking prepared SQL statements on DBs that don't support
 638          * it directly.
 639          * @param string $preparedSql - a 'preparable' SQL statement
 640          * @param array $args - array of arguments to fill it with
 641          * @return string executable SQL
 642          */
 643         function fillPrepared( $preparedQuery, $args ) {
 644                 reset( $args );
 645                 $this->preparedArgs =& $args;
 646                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 647                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 648         }
 649
 650         /**
 651          * preg_callback func for fillPrepared()
 652          * The arguments should be in $this->preparedArgs and must not be touched
 653          * while we're doing this.
 654          *
 655          * @param array $matches
 656          * @return string
 657          * @private
 658          */
 659         function fillPreparedArg( $matches ) {
 660                 switch( $matches[1] ) {
 661                         case '\\?': return '?';
 662                         case '\\!': return '!';
 663                         case '\\&': return '&';
 664                 }
 665                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 666                 switch( $matches[1] ) {
 667                         case '?': return $this->addQuotes( $arg );
 668                         case '!': return $arg;
 669                         case '&':
 670                                 # return $this->addQuotes( file_get_contents( $arg ) );
 671                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 672                         default:
 673                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 674                 }
 675         }
 676
 677         /**#@+
 678          * @param mixed $res A SQL result
 679          */
 680         /**
 681          * Free a result object
 682          */
 683         function freeResult( $res ) {
 684                 if ( $res instanceof ResultWrapper ) {
 685                         $res = $res->result;
 686                 }
 687                 if ( !@/**/mysql_free_result( $res ) ) {
 688                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 689                 }
 690         }
 691
 692         /**
 693          * Fetch the next row from the given result object, in object form.
 694          * Fields can be retrieved with $row->fieldname, with fields acting like
 695          * member variables.
 696          *
 697          * @param $res SQL result object as returned from Database::query(), etc.
 698          * @return MySQL row object
 699          * @throws DBUnexpectedError Thrown if the database returns an error
 700          */
 701         function fetchObject( $res ) {
 702                 if ( $res instanceof ResultWrapper ) {
 703                         $res = $res->result;
 704                 }
 705                 @/**/$row = mysql_fetch_object( $res );
 706                 if( $this->lastErrno() ) {
 707                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 708                 }
 709                 return $row;
 710         }
 711
 712         /**
 713          * Fetch the next row from the given result object, in associative array
 714          * form.  Fields are retrieved with $row['fieldname'].
 715          *
 716          * @param $res SQL result object as returned from Database::query(), etc.
 717          * @return MySQL row object
 718          * @throws DBUnexpectedError Thrown if the database returns an error
 719          */
 720         function fetchRow( $res ) {
 721                 if ( $res instanceof ResultWrapper ) {
 722                         $res = $res->result;
 723                 }
 724                 @/**/$row = mysql_fetch_array( $res );
 725                 if ( $this->lastErrno() ) {
 726                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 727                 }
 728                 return $row;
 729         }
 730
 731         /**
 732          * Get the number of rows in a result object
 733          */
 734         function numRows( $res ) {
 735                 if ( $res instanceof ResultWrapper ) {
 736                         $res = $res->result;
 737                 }
 738                 @/**/$n = mysql_num_rows( $res );
 739                 if( $this->lastErrno() ) {
 740                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 741                 }
 742                 return $n;
 743         }
 744
 745         /**
 746          * Get the number of fields in a result object
 747          * See documentation for mysql_num_fields()
 748          */
 749         function numFields( $res ) {
 750                 if ( $res instanceof ResultWrapper ) {
 751                         $res = $res->result;
 752                 }
 753                 return mysql_num_fields( $res );
 754         }
 755
 756         /**
 757          * Get a field name in a result object
 758          * See documentation for mysql_field_name():
 759          * http://www.php.net/mysql_field_name
 760          */
 761         function fieldName( $res, $n ) {
 762                 if ( $res instanceof ResultWrapper ) {
 763                         $res = $res->result;
 764                 }
 765                 return mysql_field_name( $res, $n );
 766         }
 767
 768         /**
 769          * Get the inserted value of an auto-increment row
 770          *
 771          * The value inserted should be fetched from nextSequenceValue()
 772          *
 773          * Example:
 774          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 775          * $dbw->insert('page',array('page_id' => $id));
 776          * $id = $dbw->insertId();
 777          */
 778         function insertId() { return mysql_insert_id( $this->mConn ); }
 779
 780         /**
 781          * Change the position of the cursor in a result object
 782          * See mysql_data_seek()
 783          */
 784         function dataSeek( $res, $row ) {
 785                 if ( $res instanceof ResultWrapper ) {
 786                         $res = $res->result;
 787                 }
 788                 return mysql_data_seek( $res, $row );
 789         }
 790
 791         /**
 792          * Get the last error number
 793          * See mysql_errno()
 794          */
 795         function lastErrno() {
 796                 if ( $this->mConn ) {
 797                         return mysql_errno( $this->mConn );
 798                 } else {
 799                         return mysql_errno();
 800                 }
 801         }
 802
 803         /**
 804          * Get a description of the last error
 805          * See mysql_error() for more details
 806          */
 807         function lastError() {
 808                 if ( $this->mConn ) {
 809                         # Even if it's non-zero, it can still be invalid
 810                         wfSuppressWarnings();
 811                         $error = mysql_error( $this->mConn );
 812                         if ( !$error ) {
 813                                 $error = mysql_error();
 814                         }
 815                         wfRestoreWarnings();
 816                 } else {
 817                         $error = mysql_error();
 818                 }
 819                 if( $error ) {
 820                         $error .= ' (' . $this->mServer . ')';
 821                 }
 822                 return $error;
 823         }
 824         /**
 825          * Get the number of rows affected by the last write query
 826          * See mysql_affected_rows() for more details
 827          */
 828         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 829         /**#@-*/ // end of template : @param $result
 830
 831         /**
 832          * Simple UPDATE wrapper
 833          * Usually aborts on failure
 834          * If errors are explicitly ignored, returns success
 835          *
 836          * This function exists for historical reasons, Database::update() has a more standard
 837          * calling convention and feature set
 838          */
 839         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 840         {
 841                 $table = $this->tableName( $table );
 842                 $sql = "UPDATE $table SET $var = '" .
 843                   $this->strencode( $value ) . "' WHERE ($cond)";
 844                 return (bool)$this->query( $sql, $fname );
 845         }
 846
 847         /**
 848          * Simple SELECT wrapper, returns a single field, input must be encoded
 849          * Usually aborts on failure
 850          * If errors are explicitly ignored, returns FALSE on failure
 851          */
 852         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 853                 if ( !is_array( $options ) ) {
 854                         $options = array( $options );
 855                 }
 856                 $options['LIMIT'] = 1;
 857
 858                 $res = $this->select( $table, $var, $cond, $fname, $options );
 859                 if ( $res === false || !$this->numRows( $res ) ) {
 860                         return false;
 861                 }
 862                 $row = $this->fetchRow( $res );
 863                 if ( $row !== false ) {
 864                         $this->freeResult( $res );
 865                         return $row[0];
 866                 } else {
 867                         return false;
 868                 }
 869         }
 870
 871         /**
 872          * Returns an optional USE INDEX clause to go after the table, and a
 873          * string to go at the end of the query
 874          *
 875          * @private
 876          *
 877          * @param array $options an associative array of options to be turned into
 878          *              an SQL query, valid keys are listed in the function.
 879          * @return array
 880          */
 881         function makeSelectOptions( $options ) {
 882                 $preLimitTail = $postLimitTail = '';
 883                 $startOpts = '';
 884
 885                 $noKeyOptions = array();
 886                 foreach ( $options as $key => $option ) {
 887                         if ( is_numeric( $key ) ) {
 888                                 $noKeyOptions[$option] = true;
 889                         }
 890                 }
 891
 892                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 893                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 894                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 895
 896                 //if (isset($options['LIMIT'])) {
 897                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 898                 //              isset($options['OFFSET']) ? $options['OFFSET']
 899                 //              : false);
 900                 //}
 901
 902                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 903                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 904                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 905
 906                 # Various MySQL extensions
 907                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 908                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 909                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 910                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 911                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 912                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 913                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 914                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 915
 916                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 917                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 918                 } else {
 919                         $useIndex = '';
 920                 }
 921
 922                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 923         }
 924
 925         /**
 926          * SELECT wrapper
 927          *
 928          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 929          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 930          * @param mixed  $conds   Array or string, condition(s) for WHERE
 931          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 932          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 933          *                        see Database::makeSelectOptions code for list of supported stuff
 934          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
 935          */
 936         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
 937         {
 938                 if( is_array( $vars ) ) {
 939                         $vars = implode( ',', $vars );
 940                 }
 941                 if( !is_array( $options ) ) {
 942                         $options = array( $options );
 943                 }
 944                 if( is_array( $table ) ) {
 945                         if ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
 946                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
 947                         else
 948                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 949                 } elseif ($table!='') {
 950                         if ($table{0}==' ') {
 951                                 $from = ' FROM ' . $table;
 952                         } else {
 953                                 $from = ' FROM ' . $this->tableName( $table );
 954                         }
 955                 } else {
 956                         $from = '';
 957                 }
 958
 959                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
 960
 961                 if( !empty( $conds ) ) {
 962                         if ( is_array( $conds ) ) {
 963                                 $conds = $this->makeList( $conds, LIST_AND );
 964                         }
 965                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
 966                 } else {
 967                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
 968                 }
 969
 970                 if (isset($options['LIMIT']))
 971                         $sql = $this->limitResult($sql, $options['LIMIT'],
 972                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 973                 $sql = "$sql $postLimitTail";
 974
 975                 if (isset($options['EXPLAIN'])) {
 976                         $sql = 'EXPLAIN ' . $sql;
 977                 }
 978                 return $this->query( $sql, $fname );
 979         }
 980
 981         /**
 982          * Single row SELECT wrapper
 983          * Aborts or returns FALSE on error
 984          *
 985          * $vars: the selected variables
 986          * $conds: a condition map, terms are ANDed together.
 987          *   Items with numeric keys are taken to be literal conditions
 988          * Takes an array of selected variables, and a condition map, which is ANDed
 989          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 990          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 991          * $obj- >page_id is the ID of the Astronomy article
 992          *
 993          * @todo migrate documentation to phpdocumentor format
 994          */
 995         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
 996                 $options['LIMIT'] = 1;
 997                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 998                 if ( $res === false )
 999                         return false;
1000                 if ( !$this->numRows($res) ) {
1001                         $this->freeResult($res);
1002                         return false;
1003                 }
1004                 $obj = $this->fetchObject( $res );
1005                 $this->freeResult( $res );
1006                 return $obj;
1007
1008         }
1009
1010         /**
1011          * Estimate rows in dataset
1012          * Returns estimated count, based on EXPLAIN output
1013          * Takes same arguments as Database::select()
1014          */
1015
1016         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1017                 $options['EXPLAIN']=true;
1018                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1019                 if ( $res === false )
1020                         return false;
1021                 if (!$this->numRows($res)) {
1022                         $this->freeResult($res);
1023                         return 0;
1024                 }
1025
1026                 $rows=1;
1027
1028                 while( $plan = $this->fetchObject( $res ) ) {
1029                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1030                 }
1031
1032                 $this->freeResult($res);
1033                 return $rows;
1034         }
1035
1036
1037         /**
1038          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1039          * It's only slightly flawed. Don't use for anything important.
1040          *
1041          * @param string $sql A SQL Query
1042          * @static
1043          */
1044         static function generalizeSQL( $sql ) {
1045                 # This does the same as the regexp below would do, but in such a way
1046                 # as to avoid crashing php on some large strings.
1047                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1048
1049                 $sql = str_replace ( "\\\\", '', $sql);
1050                 $sql = str_replace ( "\\'", '', $sql);
1051                 $sql = str_replace ( "\\\"", '', $sql);
1052                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1053                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1054
1055                 # All newlines, tabs, etc replaced by single space
1056                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1057
1058                 # All numbers => N
1059                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1060
1061                 return $sql;
1062         }
1063
1064         /**
1065          * Determines whether a field exists in a table
1066          * Usually aborts on failure
1067          * If errors are explicitly ignored, returns NULL on failure
1068          */
1069         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1070                 $table = $this->tableName( $table );
1071                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1072                 if ( !$res ) {
1073                         return NULL;
1074                 }
1075
1076                 $found = false;
1077
1078                 while ( $row = $this->fetchObject( $res ) ) {
1079                         if ( $row->Field == $field ) {
1080                                 $found = true;
1081                                 break;
1082                         }
1083                 }
1084                 return $found;
1085         }
1086
1087         /**
1088          * Determines whether an index exists
1089          * Usually aborts on failure
1090          * If errors are explicitly ignored, returns NULL on failure
1091          */
1092         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1093                 $info = $this->indexInfo( $table, $index, $fname );
1094                 if ( is_null( $info ) ) {
1095                         return NULL;
1096                 } else {
1097                         return $info !== false;
1098                 }
1099         }
1100
1101
1102         /**
1103          * Get information about an index into an object
1104          * Returns false if the index does not exist
1105          */
1106         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1107                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1108                 # SHOW INDEX should work for 3.x and up:
1109                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1110                 $table = $this->tableName( $table );
1111                 $sql = 'SHOW INDEX FROM '.$table;
1112                 $res = $this->query( $sql, $fname );
1113                 if ( !$res ) {
1114                         return NULL;
1115                 }
1116
1117                 $result = array();
1118                 while ( $row = $this->fetchObject( $res ) ) {
1119                         if ( $row->Key_name == $index ) {
1120                                 $result[] = $row;
1121                         }
1122                 }
1123                 $this->freeResult($res);
1124
1125                 return empty($result) ? false : $result;
1126         }
1127
1128         /**
1129          * Query whether a given table exists
1130          */
1131         function tableExists( $table ) {
1132                 $table = $this->tableName( $table );
1133                 $old = $this->ignoreErrors( true );
1134                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1135                 $this->ignoreErrors( $old );
1136                 if( $res ) {
1137                         $this->freeResult( $res );
1138                         return true;
1139                 } else {
1140                         return false;
1141                 }
1142         }
1143
1144         /**
1145          * mysql_fetch_field() wrapper
1146          * Returns false if the field doesn't exist
1147          *
1148          * @param $table
1149          * @param $field
1150          */
1151         function fieldInfo( $table, $field ) {
1152                 $table = $this->tableName( $table );
1153                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1154                 $n = mysql_num_fields( $res->result );
1155                 for( $i = 0; $i < $n; $i++ ) {
1156                         $meta = mysql_fetch_field( $res->result, $i );
1157                         if( $field == $meta->name ) {
1158                                 return new MySQLField($meta);
1159                         }
1160                 }
1161                 return false;
1162         }
1163
1164         /**
1165          * mysql_field_type() wrapper
1166          */
1167         function fieldType( $res, $index ) {
1168                 if ( $res instanceof ResultWrapper ) {
1169                         $res = $res->result;
1170                 }
1171                 return mysql_field_type( $res, $index );
1172         }
1173
1174         /**
1175          * Determines if a given index is unique
1176          */
1177         function indexUnique( $table, $index ) {
1178                 $indexInfo = $this->indexInfo( $table, $index );
1179                 if ( !$indexInfo ) {
1180                         return NULL;
1181                 }
1182                 return !$indexInfo[0]->Non_unique;
1183         }
1184
1185         /**
1186          * INSERT wrapper, inserts an array into a table
1187          *
1188          * $a may be a single associative array, or an array of these with numeric keys, for
1189          * multi-row insert.
1190          *
1191          * Usually aborts on failure
1192          * If errors are explicitly ignored, returns success
1193          */
1194         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1195                 # No rows to insert, easy just return now
1196                 if ( !count( $a ) ) {
1197                         return true;
1198                 }
1199
1200                 $table = $this->tableName( $table );
1201                 if ( !is_array( $options ) ) {
1202                         $options = array( $options );
1203                 }
1204                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1205                         $multi = true;
1206                         $keys = array_keys( $a[0] );
1207                 } else {
1208                         $multi = false;
1209                         $keys = array_keys( $a );
1210                 }
1211
1212                 $sql = 'INSERT ' . implode( ' ', $options ) .
1213                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1214
1215                 if ( $multi ) {
1216                         $first = true;
1217                         foreach ( $a as $row ) {
1218                                 if ( $first ) {
1219                                         $first = false;
1220                                 } else {
1221                                         $sql .= ',';
1222                                 }
1223                                 $sql .= '(' . $this->makeList( $row ) . ')';
1224                         }
1225                 } else {
1226                         $sql .= '(' . $this->makeList( $a ) . ')';
1227                 }
1228                 return (bool)$this->query( $sql, $fname );
1229         }
1230
1231         /**
1232          * Make UPDATE options for the Database::update function
1233          *
1234          * @private
1235          * @param array $options The options passed to Database::update
1236          * @return string
1237          */
1238         function makeUpdateOptions( $options ) {
1239                 if( !is_array( $options ) ) {
1240                         $options = array( $options );
1241                 }
1242                 $opts = array();
1243                 if ( in_array( 'LOW_PRIORITY', $options ) )
1244                         $opts[] = $this->lowPriorityOption();
1245                 if ( in_array( 'IGNORE', $options ) )
1246                         $opts[] = 'IGNORE';
1247                 return implode(' ', $opts);
1248         }
1249
1250         /**
1251          * UPDATE wrapper, takes a condition array and a SET array
1252          *
1253          * @param string $table  The table to UPDATE
1254          * @param array  $values An array of values to SET
1255          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1256          * @param string $fname  The Class::Function calling this function
1257          *                       (for the log)
1258          * @param array  $options An array of UPDATE options, can be one or
1259          *                        more of IGNORE, LOW_PRIORITY
1260          * @return bool
1261          */
1262         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1263                 $table = $this->tableName( $table );
1264                 $opts = $this->makeUpdateOptions( $options );
1265                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1266                 if ( $conds != '*' ) {
1267                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1268                 }
1269                 return $this->query( $sql, $fname );
1270         }
1271
1272         /**
1273          * Makes an encoded list of strings from an array
1274          * $mode:
1275          *        LIST_COMMA         - comma separated, no field names
1276          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1277          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1278          *        LIST_SET           - comma separated with field names, like a SET clause
1279          *        LIST_NAMES         - comma separated field names
1280          */
1281         function makeList( $a, $mode = LIST_COMMA ) {
1282                 if ( !is_array( $a ) ) {
1283                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1284                 }
1285
1286                 $first = true;
1287                 $list = '';
1288                 foreach ( $a as $field => $value ) {
1289                         if ( !$first ) {
1290                                 if ( $mode == LIST_AND ) {
1291                                         $list .= ' AND ';
1292                                 } elseif($mode == LIST_OR) {
1293                                         $list .= ' OR ';
1294                                 } else {
1295                                         $list .= ',';
1296                                 }
1297                         } else {
1298                                 $first = false;
1299                         }
1300                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1301                                 $list .= "($value)";
1302                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1303                                 $list .= "$value";
1304                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1305                                 if( count( $value ) == 0 ) {
1306                                         throw new MWException( __METHOD__.': empty input' );
1307                                 } elseif( count( $value ) == 1 ) {
1308                                         // Special-case single values, as IN isn't terribly efficient
1309                                         // Don't necessarily assume the single key is 0; we don't
1310                                         // enforce linear numeric ordering on other arrays here.
1311                                         $value = array_values( $value );
1312                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1313                                 } else {
1314                                         $list .= $field." IN (".$this->makeList($value).") ";
1315                                 }
1316                         } elseif( is_null($value) ) {
1317                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1318                                         $list .= "$field IS ";
1319                                 } elseif ( $mode == LIST_SET ) {
1320                                         $list .= "$field = ";
1321                                 }
1322                                 $list .= 'NULL';
1323                         } else {
1324                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1325                                         $list .= "$field = ";
1326                                 }
1327                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1328                         }
1329                 }
1330                 return $list;
1331         }
1332
1333         /**
1334          * Change the current database
1335          */
1336         function selectDB( $db ) {
1337                 $this->mDBname = $db;
1338                 return mysql_select_db( $db, $this->mConn );
1339         }
1340
1341         /**
1342          * Get the current DB name
1343          */
1344         function getDBname() {
1345                 return $this->mDBname;
1346         }
1347
1348         /**
1349          * Get the server hostname or IP address
1350          */
1351         function getServer() {
1352                 return $this->mServer;
1353         }
1354
1355         /**
1356          * Format a table name ready for use in constructing an SQL query
1357          *
1358          * This does two important things: it quotes the table names to clean them up,
1359          * and it adds a table prefix if only given a table name with no quotes.
1360          *
1361          * All functions of this object which require a table name call this function
1362          * themselves. Pass the canonical name to such functions. This is only needed
1363          * when calling query() directly.
1364          *
1365          * @param string $name database table name
1366          * @return string full database name
1367          */
1368         function tableName( $name ) {
1369                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1370                 # Skip the entire process when we have a string quoted on both ends.
1371                 # Note that we check the end so that we will still quote any use of
1372                 # use of `database`.table. But won't break things if someone wants
1373                 # to query a database table with a dot in the name.
1374                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) return $name;
1375
1376                 # Lets test for any bits of text that should never show up in a table
1377                 # name. Basically anything like JOIN or ON which are actually part of
1378                 # SQL queries, but may end up inside of the table value to combine
1379                 # sql. Such as how the API is doing.
1380                 # Note that we use a whitespace test rather than a \b test to avoid
1381                 # any remote case where a word like on may be inside of a table name
1382                 # surrounded by symbols which may be considered word breaks.
1383                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) return $name;
1384
1385                 # Split database and table into proper variables.
1386                 # We reverse the explode so that database.table and table both output
1387                 # the correct table.
1388                 @list( $table, $database ) = array_reverse( explode( '.', $name, 2 ) );
1389                 $prefix = $this->mTablePrefix; # Default prefix
1390
1391                 # A database name has been specified in input. Quote the table name
1392                 # because we don't want any prefixes added.
1393                 if( isset($database) ) $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1394
1395                 # Note that we use the long format because php will complain in in_array if
1396                 # the input is not an array, and will complain in is_array if it is not set.
1397                 if( !isset( $database ) # Don't use shared database if pre selected.
1398                  && isset( $wgSharedDB ) # We have a shared database
1399                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1400                  && isset( $wgSharedTables )
1401                  && is_array( $wgSharedTables )
1402                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1403                         $database = $wgSharedDB;
1404                         $prefix   = isset( $wgSharedprefix ) ? $wgSharedprefix : $prefix;
1405                 }
1406
1407                 # Quote the $database and $table and apply the prefix if not quoted.
1408                 if( isset($database) ) $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1409                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1410
1411                 # Merge our database and table into our final table name.
1412                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1413
1414                 # We're finished, return.
1415                 return $tableName;
1416         }
1417
1418         /**
1419          * Fetch a number of table names into an array
1420          * This is handy when you need to construct SQL for joins
1421          *
1422          * Example:
1423          * extract($dbr->tableNames('user','watchlist'));
1424          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1425          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1426          */
1427         public function tableNames() {
1428                 $inArray = func_get_args();
1429                 $retVal = array();
1430                 foreach ( $inArray as $name ) {
1431                         $retVal[$name] = $this->tableName( $name );
1432                 }
1433                 return $retVal;
1434         }
1435
1436         /**
1437          * Fetch a number of table names into an zero-indexed numerical array
1438          * This is handy when you need to construct SQL for joins
1439          *
1440          * Example:
1441          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1442          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1443          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1444          */
1445         public function tableNamesN() {
1446                 $inArray = func_get_args();
1447                 $retVal = array();
1448                 foreach ( $inArray as $name ) {
1449                         $retVal[] = $this->tableName( $name );
1450                 }
1451                 return $retVal;
1452         }
1453
1454         /**
1455          * @private
1456          */
1457         function tableNamesWithUseIndex( $tables, $use_index ) {
1458                 $ret = array();
1459
1460                 foreach ( $tables as $table )
1461                         if ( @$use_index[$table] !== null )
1462                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1463                         else
1464                                 $ret[] = $this->tableName( $table );
1465
1466                 return implode( ',', $ret );
1467         }
1468
1469         /**
1470          * Wrapper for addslashes()
1471          * @param string $s String to be slashed.
1472          * @return string slashed string.
1473          */
1474         function strencode( $s ) {
1475                 return mysql_real_escape_string( $s, $this->mConn );
1476         }
1477
1478         /**
1479          * If it's a string, adds quotes and backslashes
1480          * Otherwise returns as-is
1481          */
1482         function addQuotes( $s ) {
1483                 if ( is_null( $s ) ) {
1484                         return 'NULL';
1485                 } else {
1486                         # This will also quote numeric values. This should be harmless,
1487                         # and protects against weird problems that occur when they really
1488                         # _are_ strings such as article titles and string->number->string
1489                         # conversion is not 1:1.
1490                         return "'" . $this->strencode( $s ) . "'";
1491                 }
1492         }
1493
1494         /**
1495          * Escape string for safe LIKE usage
1496          */
1497         function escapeLike( $s ) {
1498                 $s=$this->strencode( $s );
1499                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1500                 return $s;
1501         }
1502
1503         /**
1504          * Returns an appropriately quoted sequence value for inserting a new row.
1505          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1506          * subclass will return an integer, and save the value for insertId()
1507          */
1508         function nextSequenceValue( $seqName ) {
1509                 return NULL;
1510         }
1511
1512         /**
1513          * USE INDEX clause
1514          * PostgreSQL doesn't have them and returns ""
1515          */
1516         function useIndexClause( $index ) {
1517                 return "FORCE INDEX ($index)";
1518         }
1519
1520         /**
1521          * REPLACE query wrapper
1522          * PostgreSQL simulates this with a DELETE followed by INSERT
1523          * $row is the row to insert, an associative array
1524          * $uniqueIndexes is an array of indexes. Each element may be either a
1525          * field name or an array of field names
1526          *
1527          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1528          * However if you do this, you run the risk of encountering errors which wouldn't have
1529          * occurred in MySQL
1530          *
1531          * @todo migrate comment to phodocumentor format
1532          */
1533         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1534                 $table = $this->tableName( $table );
1535
1536                 # Single row case
1537                 if ( !is_array( reset( $rows ) ) ) {
1538                         $rows = array( $rows );
1539                 }
1540
1541                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1542                 $first = true;
1543                 foreach ( $rows as $row ) {
1544                         if ( $first ) {
1545                                 $first = false;
1546                         } else {
1547                                 $sql .= ',';
1548                         }
1549                         $sql .= '(' . $this->makeList( $row ) . ')';
1550                 }
1551                 return $this->query( $sql, $fname );
1552         }
1553
1554         /**
1555          * DELETE where the condition is a join
1556          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1557          *
1558          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1559          * join condition matches, set $conds='*'
1560          *
1561          * DO NOT put the join condition in $conds
1562          *
1563          * @param string $delTable The table to delete from.
1564          * @param string $joinTable The other table.
1565          * @param string $delVar The variable to join on, in the first table.
1566          * @param string $joinVar The variable to join on, in the second table.
1567          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1568          */
1569         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1570                 if ( !$conds ) {
1571                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1572                 }
1573
1574                 $delTable = $this->tableName( $delTable );
1575                 $joinTable = $this->tableName( $joinTable );
1576                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1577                 if ( $conds != '*' ) {
1578                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1579                 }
1580
1581                 return $this->query( $sql, $fname );
1582         }
1583
1584         /**
1585          * Returns the size of a text field, or -1 for "unlimited"
1586          */
1587         function textFieldSize( $table, $field ) {
1588                 $table = $this->tableName( $table );
1589                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1590                 $res = $this->query( $sql, 'Database::textFieldSize' );
1591                 $row = $this->fetchObject( $res );
1592                 $this->freeResult( $res );
1593
1594                 $m = array();
1595                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1596                         $size = $m[1];
1597                 } else {
1598                         $size = -1;
1599                 }
1600                 return $size;
1601         }
1602
1603         /**
1604          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1605          */
1606         function lowPriorityOption() {
1607                 return 'LOW_PRIORITY';
1608         }
1609
1610         /**
1611          * DELETE query wrapper
1612          *
1613          * Use $conds == "*" to delete all rows
1614          */
1615         function delete( $table, $conds, $fname = 'Database::delete' ) {
1616                 if ( !$conds ) {
1617                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1618                 }
1619                 $table = $this->tableName( $table );
1620                 $sql = "DELETE FROM $table";
1621                 if ( $conds != '*' ) {
1622                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1623                 }
1624                 return $this->query( $sql, $fname );
1625         }
1626
1627         /**
1628          * INSERT SELECT wrapper
1629          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1630          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1631          * $conds may be "*" to copy the whole table
1632          * srcTable may be an array of tables.
1633          */
1634         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1635                 $insertOptions = array(), $selectOptions = array() )
1636         {
1637                 $destTable = $this->tableName( $destTable );
1638                 if ( is_array( $insertOptions ) ) {
1639                         $insertOptions = implode( ' ', $insertOptions );
1640                 }
1641                 if( !is_array( $selectOptions ) ) {
1642                         $selectOptions = array( $selectOptions );
1643                 }
1644                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1645                 if( is_array( $srcTable ) ) {
1646                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1647                 } else {
1648                         $srcTable = $this->tableName( $srcTable );
1649                 }
1650                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1651                         " SELECT $startOpts " . implode( ',', $varMap ) .
1652                         " FROM $srcTable $useIndex ";
1653                 if ( $conds != '*' ) {
1654                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1655                 }
1656                 $sql .= " $tailOpts";
1657                 return $this->query( $sql, $fname );
1658         }
1659
1660         /**
1661          * Construct a LIMIT query with optional offset
1662          * This is used for query pages
1663          * $sql string SQL query we will append the limit too
1664          * $limit integer the SQL limit
1665          * $offset integer the SQL offset (default false)
1666          */
1667         function limitResult($sql, $limit, $offset=false) {
1668                 if( !is_numeric($limit) ) {
1669                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1670                 }
1671                 return "$sql LIMIT "
1672                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1673                                 . "{$limit} ";
1674         }
1675         function limitResultForUpdate($sql, $num) {
1676                 return $this->limitResult($sql, $num, 0);
1677         }
1678
1679         /**
1680          * Returns an SQL expression for a simple conditional.
1681          * Uses IF on MySQL.
1682          *
1683          * @param string $cond SQL expression which will result in a boolean value
1684          * @param string $trueVal SQL expression to return if true
1685          * @param string $falseVal SQL expression to return if false
1686          * @return string SQL fragment
1687          */
1688         function conditional( $cond, $trueVal, $falseVal ) {
1689                 return " IF($cond, $trueVal, $falseVal) ";
1690         }
1691
1692         /**
1693          * Returns a comand for str_replace function in SQL query.
1694          * Uses REPLACE() in MySQL
1695          *
1696          * @param string $orig String or column to modify
1697          * @param string $old String or column to seek
1698          * @param string $new String or column to replace with
1699          */
1700         function strreplace( $orig, $old, $new ) {
1701                 return "REPLACE({$orig}, {$old}, {$new})";
1702         }
1703
1704         /**
1705          * Determines if the last failure was due to a deadlock
1706          */
1707         function wasDeadlock() {
1708                 return $this->lastErrno() == 1213;
1709         }
1710
1711         /**
1712          * Perform a deadlock-prone transaction.
1713          *
1714          * This function invokes a callback function to perform a set of write
1715          * queries. If a deadlock occurs during the processing, the transaction
1716          * will be rolled back and the callback function will be called again.
1717          *
1718          * Usage:
1719          *   $dbw->deadlockLoop( callback, ... );
1720          *
1721          * Extra arguments are passed through to the specified callback function.
1722          *
1723          * Returns whatever the callback function returned on its successful,
1724          * iteration, or false on error, for example if the retry limit was
1725          * reached.
1726          */
1727         function deadlockLoop() {
1728                 $myFname = 'Database::deadlockLoop';
1729
1730                 $this->begin();
1731                 $args = func_get_args();
1732                 $function = array_shift( $args );
1733                 $oldIgnore = $this->ignoreErrors( true );
1734                 $tries = DEADLOCK_TRIES;
1735                 if ( is_array( $function ) ) {
1736                         $fname = $function[0];
1737                 } else {
1738                         $fname = $function;
1739                 }
1740                 do {
1741                         $retVal = call_user_func_array( $function, $args );
1742                         $error = $this->lastError();
1743                         $errno = $this->lastErrno();
1744                         $sql = $this->lastQuery();
1745
1746                         if ( $errno ) {
1747                                 if ( $this->wasDeadlock() ) {
1748                                         # Retry
1749                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1750                                 } else {
1751                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1752                                 }
1753                         }
1754                 } while( $this->wasDeadlock() && --$tries > 0 );
1755                 $this->ignoreErrors( $oldIgnore );
1756                 if ( $tries <= 0 ) {
1757                         $this->query( 'ROLLBACK', $myFname );
1758                         $this->reportQueryError( $error, $errno, $sql, $fname );
1759                         return false;
1760                 } else {
1761                         $this->query( 'COMMIT', $myFname );
1762                         return $retVal;
1763                 }
1764         }
1765
1766         /**
1767          * Do a SELECT MASTER_POS_WAIT()
1768          *
1769          * @param string $file the binlog file
1770          * @param string $pos the binlog position
1771          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1772          */
1773         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1774                 $fname = 'Database::masterPosWait';
1775                 wfProfileIn( $fname );
1776
1777                 # Commit any open transactions
1778                 if ( $this->mTrxLevel ) {
1779                         $this->immediateCommit();
1780                 }
1781
1782                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1783                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1784                         if ( $wait > $timeout * 1e6 ) {
1785                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1786                                 wfProfileOut( $fname );
1787                                 return -1;
1788                         } elseif ( $wait > 0 ) {
1789                                 wfDebug( "Fake slave waiting $wait us\n" );
1790                                 usleep( $wait );
1791                                 wfProfileOut( $fname );
1792                                 return 1;
1793                         } else {
1794                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1795                                 wfProfileOut( $fname );
1796                                 return 0;
1797                         }
1798                 }
1799
1800                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1801                 $encFile = $this->addQuotes( $pos->file );
1802                 $encPos = intval( $pos->pos );
1803                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1804                 $res = $this->doQuery( $sql );
1805                 if ( $res && $row = $this->fetchRow( $res ) ) {
1806                         $this->freeResult( $res );
1807                         wfProfileOut( $fname );
1808                         return $row[0];
1809                 } else {
1810                         wfProfileOut( $fname );
1811                         return false;
1812                 }
1813         }
1814
1815         /**
1816          * Get the position of the master from SHOW SLAVE STATUS
1817          */
1818         function getSlavePos() {
1819                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1820                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1821                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1822                         return $pos;
1823                 }
1824                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1825                 $row = $this->fetchObject( $res );
1826                 if ( $row ) {
1827                         return new MySQLMasterPos( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1828                 } else {
1829                         return false;
1830                 }
1831         }
1832
1833         /**
1834          * Get the position of the master from SHOW MASTER STATUS
1835          */
1836         function getMasterPos() {
1837                 if ( $this->mFakeMaster ) {
1838                         return new MySQLMasterPos( 'fake', microtime( true ) );
1839                 }
1840                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1841                 $row = $this->fetchObject( $res );
1842                 if ( $row ) {
1843                         return new MySQLMasterPos( $row->File, $row->Position );
1844                 } else {
1845                         return false;
1846                 }
1847         }
1848
1849         /**
1850          * Begin a transaction, committing any previously open transaction
1851          */
1852         function begin( $fname = 'Database::begin' ) {
1853                 $this->query( 'BEGIN', $fname );
1854                 $this->mTrxLevel = 1;
1855         }
1856
1857         /**
1858          * End a transaction
1859          */
1860         function commit( $fname = 'Database::commit' ) {
1861                 $this->query( 'COMMIT', $fname );
1862                 $this->mTrxLevel = 0;
1863         }
1864
1865         /**
1866          * Rollback a transaction.
1867          * No-op on non-transactional databases.
1868          */
1869         function rollback( $fname = 'Database::rollback' ) {
1870                 $this->query( 'ROLLBACK', $fname, true );
1871                 $this->mTrxLevel = 0;
1872         }
1873
1874         /**
1875          * Begin a transaction, committing any previously open transaction
1876          * @deprecated use begin()
1877          */
1878         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1879                 $this->begin();
1880         }
1881
1882         /**
1883          * Commit transaction, if one is open
1884          * @deprecated use commit()
1885          */
1886         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1887                 $this->commit();
1888         }
1889
1890         /**
1891          * Return MW-style timestamp used for MySQL schema
1892          */
1893         function timestamp( $ts=0 ) {
1894                 return wfTimestamp(TS_MW,$ts);
1895         }
1896
1897         /**
1898          * Local database timestamp format or null
1899          */
1900         function timestampOrNull( $ts = null ) {
1901                 if( is_null( $ts ) ) {
1902                         return null;
1903                 } else {
1904                         return $this->timestamp( $ts );
1905                 }
1906         }
1907
1908         /**
1909          * @todo document
1910          */
1911         function resultObject( $result ) {
1912                 if( empty( $result ) ) {
1913                         return false;
1914                 } elseif ( $result instanceof ResultWrapper ) {
1915                         return $result;
1916                 } elseif ( $result === true ) {
1917                         // Successful write query
1918                         return $result;
1919                 } else {
1920                         return new ResultWrapper( $this, $result );
1921                 }
1922         }
1923
1924         /**
1925          * Return aggregated value alias
1926          */
1927         function aggregateValue ($valuedata,$valuename='value') {
1928                 return $valuename;
1929         }
1930
1931         /**
1932          * @return string wikitext of a link to the server software's web site
1933          */
1934         function getSoftwareLink() {
1935                 return "[http://www.mysql.com/ MySQL]";
1936         }
1937
1938         /**
1939          * @return string Version information from the database
1940          */
1941         function getServerVersion() {
1942                 return mysql_get_server_info( $this->mConn );
1943         }
1944
1945         /**
1946          * Ping the server and try to reconnect if it there is no connection
1947          */
1948         function ping() {
1949                 if( !function_exists( 'mysql_ping' ) ) {
1950                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1951                         return true;
1952                 }
1953                 $ping = mysql_ping( $this->mConn );
1954                 if ( $ping ) {
1955                         return true;
1956                 }
1957
1958                 // Need to reconnect manually in MySQL client 5.0.13+
1959                 if ( version_compare( mysql_get_client_info(), '5.0.13', '>=' ) ) {
1960                         mysql_close( $this->mConn );
1961                         $this->mOpened = false;
1962                         $this->mConn = false;
1963                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
1964                         return true;
1965                 }
1966                 return false;
1967         }
1968
1969         /**
1970          * Get slave lag.
1971          * At the moment, this will only work if the DB user has the PROCESS privilege
1972          */
1973         function getLag() {
1974                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1975                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
1976                         return $this->mFakeSlaveLag;
1977                 }
1978                 $res = $this->query( 'SHOW PROCESSLIST' );
1979                 # Find slave SQL thread
1980                 while ( $row = $this->fetchObject( $res ) ) {
1981                         /* This should work for most situations - when default db
1982                          * for thread is not specified, it had no events executed,
1983                          * and therefore it doesn't know yet how lagged it is.
1984                          *
1985                          * Relay log I/O thread does not select databases.
1986                          */
1987                         if ( $row->User == 'system user' &&
1988                                 $row->State != 'Waiting for master to send event' &&
1989                                 $row->State != 'Connecting to master' &&
1990                                 $row->State != 'Queueing master event to the relay log' &&
1991                                 $row->State != 'Waiting for master update' &&
1992                                 $row->State != 'Requesting binlog dump'
1993                                 ) {
1994                                 # This is it, return the time (except -ve)
1995                                 if ( $row->Time > 0x7fffffff ) {
1996                                         return false;
1997                                 } else {
1998                                         return $row->Time;
1999                                 }
2000                         }
2001                 }
2002                 return false;
2003         }
2004
2005         /**
2006          * Get status information from SHOW STATUS in an associative array
2007          */
2008         function getStatus($which="%") {
2009                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2010                 $status = array();
2011                 while ( $row = $this->fetchObject( $res ) ) {
2012                         $status[$row->Variable_name] = $row->Value;
2013                 }
2014                 return $status;
2015         }
2016
2017         /**
2018          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2019          */
2020         function maxListLen() {
2021                 return 0;
2022         }
2023
2024         function encodeBlob($b) {
2025                 return $b;
2026         }
2027
2028         function decodeBlob($b) {
2029                 return $b;
2030         }
2031
2032         /**
2033          * Override database's default connection timeout.
2034          * May be useful for very long batch queries such as
2035          * full-wiki dumps, where a single query reads out
2036          * over hours or days.
2037          * @param int $timeout in seconds
2038          */
2039         public function setTimeout( $timeout ) {
2040                 $this->query( "SET net_read_timeout=$timeout" );
2041                 $this->query( "SET net_write_timeout=$timeout" );
2042         }
2043
2044         /**
2045          * Read and execute SQL commands from a file.
2046          * Returns true on success, error string on failure
2047          * @param string $filename File name to open
2048          * @param callback $lineCallback Optional function called before reading each line
2049          * @param callback $resultCallback Optional function called for each MySQL result
2050          */
2051         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2052                 $fp = fopen( $filename, 'r' );
2053                 if ( false === $fp ) {
2054                         return "Could not open \"{$filename}\".\n";
2055                 }
2056                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2057                 fclose( $fp );
2058                 return $error;
2059         }
2060
2061         /**
2062          * Read and execute commands from an open file handle
2063          * Returns true on success, error string on failure
2064          * @param string $fp File handle
2065          * @param callback $lineCallback Optional function called before reading each line
2066          * @param callback $resultCallback Optional function called for each MySQL result
2067          */
2068         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2069                 $cmd = "";
2070                 $done = false;
2071                 $dollarquote = false;
2072
2073                 while ( ! feof( $fp ) ) {
2074                         if ( $lineCallback ) {
2075                                 call_user_func( $lineCallback );
2076                         }
2077                         $line = trim( fgets( $fp, 1024 ) );
2078                         $sl = strlen( $line ) - 1;
2079
2080                         if ( $sl < 0 ) { continue; }
2081                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2082
2083                         ## Allow dollar quoting for function declarations
2084                         if (substr($line,0,4) == '$mw$') {
2085                                 if ($dollarquote) {
2086                                         $dollarquote = false;
2087                                         $done = true;
2088                                 }
2089                                 else {
2090                                         $dollarquote = true;
2091                                 }
2092                         }
2093                         else if (!$dollarquote) {
2094                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2095                                         $done = true;
2096                                         $line = substr( $line, 0, $sl );
2097                                 }
2098                         }
2099
2100                         if ( '' != $cmd ) { $cmd .= ' '; }
2101                         $cmd .= "$line\n";
2102
2103                         if ( $done ) {
2104                                 $cmd = str_replace(';;', ";", $cmd);
2105                                 $cmd = $this->replaceVars( $cmd );
2106                                 $res = $this->query( $cmd, __METHOD__, true );
2107                                 if ( $resultCallback ) {
2108                                         call_user_func( $resultCallback, $res );
2109                                 }
2110
2111                                 if ( false === $res ) {
2112                                         $err = $this->lastError();
2113                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2114                                 }
2115
2116                                 $cmd = '';
2117                                 $done = false;
2118                         }
2119                 }
2120                 return true;
2121         }
2122
2123
2124         /**
2125          * Replace variables in sourced SQL
2126          */
2127         protected function replaceVars( $ins ) {
2128                 $varnames = array(
2129                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2130                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2131                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2132                 );
2133
2134                 // Ordinary variables
2135                 foreach ( $varnames as $var ) {
2136                         if( isset( $GLOBALS[$var] ) ) {
2137                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2138                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2139                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2140                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2141                         }
2142                 }
2143
2144                 // Table prefixes
2145                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
2146                         array( &$this, 'tableNameCallback' ), $ins );
2147                 return $ins;
2148         }
2149
2150         /**
2151          * Table name callback
2152          * @private
2153          */
2154         protected function tableNameCallback( $matches ) {
2155                 return $this->tableName( $matches[1] );
2156         }
2157
2158         /*
2159          * Build a concatenation list to feed into a SQL query
2160         */
2161         function buildConcat( $stringList ) {
2162                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2163         }
2164
2165 }
2166
2167 /**
2168  * Database abstraction object for mySQL
2169  * Inherit all methods and properties of Database::Database()
2170  *
2171  * @addtogroup Database
2172  * @see Database
2173  */
2174 class DatabaseMysql extends Database {
2175         # Inherit all
2176 }
2177
2178 /******************************************************************************
2179  * Utility classes
2180  *****************************************************************************/
2181
2182 /**
2183  * Utility class.
2184  * @addtogroup Database
2185  */
2186 class DBObject {
2187         public $mData;
2188
2189         function DBObject($data) {
2190                 $this->mData = $data;
2191         }
2192
2193         function isLOB() {
2194                 return false;
2195         }
2196
2197         function data() {
2198                 return $this->mData;
2199         }
2200 }
2201
2202 /**
2203  * Utility class
2204  * @addtogroup Database
2205  *
2206  * This allows us to distinguish a blob from a normal string and an array of strings
2207  */
2208 class Blob {
2209         private $mData;
2210         function __construct($data) {
2211                 $this->mData = $data;
2212         }
2213         function fetch() {
2214                 return $this->mData;
2215         }
2216 }
2217
2218 /**
2219  * Utility class.
2220  * @addtogroup Database
2221  */
2222 class MySQLField {
2223         private $name, $tablename, $default, $max_length, $nullable,
2224                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2225         function __construct ($info) {
2226                 $this->name = $info->name;
2227                 $this->tablename = $info->table;
2228                 $this->default = $info->def;
2229                 $this->max_length = $info->max_length;
2230                 $this->nullable = !$info->not_null;
2231                 $this->is_pk = $info->primary_key;
2232                 $this->is_unique = $info->unique_key;
2233                 $this->is_multiple = $info->multiple_key;
2234                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2235                 $this->type = $info->type;
2236         }
2237
2238         function name() {
2239                 return $this->name;
2240         }
2241
2242         function tableName() {
2243                 return $this->tableName;
2244         }
2245
2246         function defaultValue() {
2247                 return $this->default;
2248         }
2249
2250         function maxLength() {
2251                 return $this->max_length;
2252         }
2253
2254         function nullable() {
2255                 return $this->nullable;
2256         }
2257
2258         function isKey() {
2259                 return $this->is_key;
2260         }
2261
2262         function isMultipleKey() {
2263                 return $this->is_multiple;
2264         }
2265
2266         function type() {
2267                 return $this->type;
2268         }
2269 }
2270
2271 /******************************************************************************
2272  * Error classes
2273  *****************************************************************************/
2274
2275 /**
2276  * Database error base class
2277  * @addtogroup Database
2278  */
2279 class DBError extends MWException {
2280         public $db;
2281
2282         /**
2283          * Construct a database error
2284          * @param Database $db The database object which threw the error
2285          * @param string $error A simple error message to be used for debugging
2286          */
2287         function __construct( Database &$db, $error ) {
2288                 $this->db =& $db;
2289                 parent::__construct( $error );
2290         }
2291 }
2292
2293 /**
2294  * @addtogroup Database
2295  */
2296 class DBConnectionError extends DBError {
2297         public $error;
2298
2299         function __construct( Database &$db, $error = 'unknown error' ) {
2300                 $msg = 'DB connection error';
2301                 if ( trim( $error ) != '' ) {
2302                         $msg .= ": $error";
2303                 }
2304                 $this->error = $error;
2305                 parent::__construct( $db, $msg );
2306         }
2307
2308         function useOutputPage() {
2309                 // Not likely to work
2310                 return false;
2311         }
2312
2313         function useMessageCache() {
2314                 // Not likely to work
2315                 return false;
2316         }
2317
2318         function getText() {
2319                 return $this->getMessage() . "\n";
2320         }
2321
2322         function getLogMessage() {
2323                 # Don't send to the exception log
2324                 return false;
2325         }
2326
2327         function getPageTitle() {
2328                 global $wgSitename;
2329                 return "$wgSitename has a problem";
2330         }
2331
2332         function getHTML() {
2333                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
2334                 global $wgSitename, $wgServer, $wgMessageCache;
2335
2336                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
2337                 # Hard coding strings instead.
2338
2339                 $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>";
2340                 $mainpage = 'Main Page';
2341                 $searchdisabled = <<<EOT
2342 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
2343 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
2344 EOT;
2345
2346                 $googlesearch = "
2347 <!-- SiteSearch Google -->
2348 <FORM method=GET action=\"http://www.google.com/search\">
2349 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
2350 <A HREF=\"http://www.google.com/\">
2351 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
2352 border=\"0\" ALT=\"Google\"></A>
2353 </td>
2354 <td>
2355 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
2356 <INPUT type=submit name=btnG VALUE=\"Google Search\">
2357 <font size=-1>
2358 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
2359 <input type='hidden' name='ie' value='$2'>
2360 <input type='hidden' name='oe' value='$2'>
2361 </font>
2362 </td></tr></TABLE>
2363 </FORM>
2364 <!-- SiteSearch Google -->";
2365                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
2366
2367                 # No database access
2368                 if ( is_object( $wgMessageCache ) ) {
2369                         $wgMessageCache->disable();
2370                 }
2371
2372                 if ( trim( $this->error ) == '' ) {
2373                         $this->error = $this->db->getProperty('mServer');
2374                 }
2375
2376                 $text = str_replace( '$1', $this->error, $noconnect );
2377                 $text .= wfGetSiteNotice();
2378
2379                 if($wgUseFileCache) {
2380                         if($wgTitle) {
2381                                 $t =& $wgTitle;
2382                         } else {
2383                                 if($title) {
2384                                         $t = Title::newFromURL( $title );
2385                                 } elseif (@/**/$_REQUEST['search']) {
2386                                         $search = $_REQUEST['search'];
2387                                         return $searchdisabled .
2388                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
2389                                           $wgInputEncoding ), $googlesearch );
2390                                 } else {
2391                                         $t = Title::newFromText( $mainpage );
2392                                 }
2393                         }
2394
2395                         $cache = new HTMLFileCache( $t );
2396                         if( $cache->isFileCached() ) {
2397                                 // @todo, FIXME: $msg is not defined on the next line.
2398                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
2399                                         $cachederror . "</b></p>\n";
2400
2401                                 $tag = '<div id="article">';
2402                                 $text = str_replace(
2403                                         $tag,
2404                                         $tag . $msg,
2405                                         $cache->fetchPageText() );
2406                         }
2407                 }
2408
2409                 return $text;
2410         }
2411 }
2412
2413 /**
2414  * @addtogroup Database
2415  */
2416 class DBQueryError extends DBError {
2417         public $error, $errno, $sql, $fname;
2418
2419         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
2420                 $message = "A database error has occurred\n" .
2421                   "Query: $sql\n" .
2422                   "Function: $fname\n" .
2423                   "Error: $errno $error\n";
2424
2425                 parent::__construct( $db, $message );
2426                 $this->error = $error;
2427                 $this->errno = $errno;
2428                 $this->sql = $sql;
2429                 $this->fname = $fname;
2430         }
2431
2432         function getText() {
2433                 if ( $this->useMessageCache() ) {
2434                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2435                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2436                 } else {
2437                         return $this->getMessage();
2438                 }
2439         }
2440
2441         function getSQL() {
2442                 global $wgShowSQLErrors;
2443                 if( !$wgShowSQLErrors ) {
2444                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2445                 } else {
2446                         return $this->sql;
2447                 }
2448         }
2449
2450         function getLogMessage() {
2451                 # Don't send to the exception log
2452                 return false;
2453         }
2454
2455         function getPageTitle() {
2456                 return $this->msg( 'databaseerror', 'Database error' );
2457         }
2458
2459         function getHTML() {
2460                 if ( $this->useMessageCache() ) {
2461                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2462                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2463                 } else {
2464                         return nl2br( htmlspecialchars( $this->getMessage() ) );
2465                 }
2466         }
2467 }
2468
2469 /**
2470  * @addtogroup Database
2471  */
2472 class DBUnexpectedError extends DBError {}
2473
2474
2475 /**
2476  * Result wrapper for grabbing data queried by someone else
2477  * @addtogroup Database
2478  */
2479 class ResultWrapper implements Iterator {
2480         var $db, $result, $pos = 0, $currentRow = null;
2481
2482         /**
2483          * Create a new result object from a result resource and a Database object
2484          */
2485         function ResultWrapper( $database, $result ) {
2486                 $this->db = $database;
2487                 if ( $result instanceof ResultWrapper ) {
2488                         $this->result = $result->result;
2489                 } else {
2490                         $this->result = $result;
2491                 }
2492         }
2493
2494         /**
2495          * Get the number of rows in a result object
2496          */
2497         function numRows() {
2498                 return $this->db->numRows( $this->result );
2499         }
2500
2501         /**
2502          * Fetch the next row from the given result object, in object form.
2503          * Fields can be retrieved with $row->fieldname, with fields acting like
2504          * member variables.
2505          *
2506          * @param $res SQL result object as returned from Database::query(), etc.
2507          * @return MySQL row object
2508          * @throws DBUnexpectedError Thrown if the database returns an error
2509          */
2510         function fetchObject() {
2511                 return $this->db->fetchObject( $this->result );
2512         }
2513
2514         /**
2515          * Fetch the next row from the given result object, in associative array
2516          * form.  Fields are retrieved with $row['fieldname'].
2517          *
2518          * @param $res SQL result object as returned from Database::query(), etc.
2519          * @return MySQL row object
2520          * @throws DBUnexpectedError Thrown if the database returns an error
2521          */
2522         function fetchRow() {
2523                 return $this->db->fetchRow( $this->result );
2524         }
2525
2526         /**
2527          * Free a result object
2528          */
2529         function free() {
2530                 $this->db->freeResult( $this->result );
2531                 unset( $this->result );
2532                 unset( $this->db );
2533         }
2534
2535         /**
2536          * Change the position of the cursor in a result object
2537          * See mysql_data_seek()
2538          */
2539         function seek( $row ) {
2540                 $this->db->dataSeek( $this->result, $row );
2541         }
2542
2543         /*********************
2544          * Iterator functions
2545          * Note that using these in combination with the non-iterator functions
2546          * above may cause rows to be skipped or repeated.
2547          */
2548
2549         function rewind() {
2550                 if ($this->numRows()) {
2551                         $this->db->dataSeek($this->result, 0);
2552                 }
2553                 $this->pos = 0;
2554                 $this->currentRow = null;
2555         }
2556
2557         function current() {
2558                 if ( is_null( $this->currentRow ) ) {
2559                         $this->next();
2560                 }
2561                 return $this->currentRow;
2562         }
2563
2564         function key() {
2565                 return $this->pos;
2566         }
2567
2568         function next() {
2569                 $this->pos++;
2570                 $this->currentRow = $this->fetchObject();
2571                 return $this->currentRow;
2572         }
2573
2574         function valid() {
2575                 return $this->current() !== false;
2576         }
2577 }
2578
2579 class MySQLMasterPos {
2580         var $file, $pos;
2581
2582         function __construct( $file, $pos ) {
2583                 $this->file = $file;
2584                 $this->pos = $pos;
2585         }
2586
2587         function __toString() {
2588                 return "{$this->file}/{$this->pos}";
2589         }
2590 }