includes/db/Database.php

   1 <?php
   2 /**
   3  * @defgroup Database Database
   4  *
   5  * @file
   6  * @ingroup Database
   7  * This file deals with MySQL interface functions
   8  * and query specifics/optimisations
   9  */
  10
  11 /** Number of times to re-try an operation in case of deadlock */
  12 define( 'DEADLOCK_TRIES', 4 );
  13 /** Minimum time to wait before retry, in microseconds */
  14 define( 'DEADLOCK_DELAY_MIN', 500000 );
  15 /** Maximum time to wait before retry */
  16 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  17
  18 /**
  19  * Database abstraction object
  20  * @ingroup Database
  21  */
  22 class Database {
  23
  24 #------------------------------------------------------------------------------
  25 # Variables
  26 #------------------------------------------------------------------------------
  27
  28         protected $mLastQuery = '';
  29         protected $mPHPError = false;
  30
  31         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  32         protected $mOpened = false;
  33
  34         protected $mFailFunction;
  35         protected $mTablePrefix;
  36         protected $mFlags;
  37         protected $mTrxLevel = 0;
  38         protected $mErrorCount = 0;
  39         protected $mLBInfo = array();
  40         protected $mFakeSlaveLag = null, $mFakeMaster = false;
  41
  42 #------------------------------------------------------------------------------
  43 # Accessors
  44 #------------------------------------------------------------------------------
  45         # These optionally set a variable and return the previous state
  46
  47         /**
  48          * Fail function, takes a Database as a parameter
  49          * Set to false for default, 1 for ignore errors
  50          */
  51         function failFunction( $function = NULL ) {
  52                 return wfSetVar( $this->mFailFunction, $function );
  53         }
  54
  55         /**
  56          * Output page, used for reporting errors
  57          * FALSE means discard output
  58          */
  59         function setOutputPage( $out ) {
  60                 wfDeprecated( __METHOD__ );
  61         }
  62
  63         /**
  64          * Boolean, controls output of large amounts of debug information
  65          */
  66         function debug( $debug = NULL ) {
  67                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  68         }
  69
  70         /**
  71          * Turns buffering of SQL result sets on (true) or off (false).
  72          * Default is "on" and it should not be changed without good reasons.
  73          */
  74         function bufferResults( $buffer = NULL ) {
  75                 if ( is_null( $buffer ) ) {
  76                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  77                 } else {
  78                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  79                 }
  80         }
  81
  82         /**
  83          * Turns on (false) or off (true) the automatic generation and sending
  84          * of a "we're sorry, but there has been a database error" page on
  85          * database errors. Default is on (false). When turned off, the
  86          * code should use lastErrno() and lastError() to handle the
  87          * situation as appropriate.
  88          */
  89         function ignoreErrors( $ignoreErrors = NULL ) {
  90                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  91         }
  92
  93         /**
  94          * The current depth of nested transactions
  95          * @param $level Integer: , default NULL.
  96          */
  97         function trxLevel( $level = NULL ) {
  98                 return wfSetVar( $this->mTrxLevel, $level );
  99         }
 100
 101         /**
 102          * Number of errors logged, only useful when errors are ignored
 103          */
 104         function errorCount( $count = NULL ) {
 105                 return wfSetVar( $this->mErrorCount, $count );
 106         }
 107
 108         function tablePrefix( $prefix = null ) {
 109                 return wfSetVar( $this->mTablePrefix, $prefix );
 110         }
 111
 112         /**
 113          * Properties passed down from the server info array of the load balancer
 114          */
 115         function getLBInfo( $name = NULL ) {
 116                 if ( is_null( $name ) ) {
 117                         return $this->mLBInfo;
 118                 } else {
 119                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 120                                 return $this->mLBInfo[$name];
 121                         } else {
 122                                 return NULL;
 123                         }
 124                 }
 125         }
 126
 127         function setLBInfo( $name, $value = NULL ) {
 128                 if ( is_null( $value ) ) {
 129                         $this->mLBInfo = $name;
 130                 } else {
 131                         $this->mLBInfo[$name] = $value;
 132                 }
 133         }
 134
 135         /**
 136          * Set lag time in seconds for a fake slave
 137          */
 138         function setFakeSlaveLag( $lag ) {
 139                 $this->mFakeSlaveLag = $lag;
 140         }
 141
 142         /**
 143          * Make this connection a fake master
 144          */
 145         function setFakeMaster( $enabled = true ) {
 146                 $this->mFakeMaster = $enabled;
 147         }
 148
 149         /**
 150          * Returns true if this database supports (and uses) cascading deletes
 151          */
 152         function cascadingDeletes() {
 153                 return false;
 154         }
 155
 156         /**
 157          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 158          */
 159         function cleanupTriggers() {
 160                 return false;
 161         }
 162
 163         /**
 164          * Returns true if this database is strict about what can be put into an IP field.
 165          * Specifically, it uses a NULL value instead of an empty string.
 166          */
 167         function strictIPs() {
 168                 return false;
 169         }
 170
 171         /**
 172          * Returns true if this database uses timestamps rather than integers
 173         */
 174         function realTimestamps() {
 175                 return false;
 176         }
 177
 178         /**
 179          * Returns true if this database does an implicit sort when doing GROUP BY
 180          */
 181         function implicitGroupby() {
 182                 return true;
 183         }
 184
 185         /**
 186          * Returns true if this database does an implicit order by when the column has an index
 187          * For example: SELECT page_title FROM page LIMIT 1
 188          */
 189         function implicitOrderby() {
 190                 return true;
 191         }
 192
 193         /**
 194          * Returns true if this database can do a native search on IP columns
 195          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 196          */
 197         function searchableIPs() {
 198                 return false;
 199         }
 200
 201         /**
 202          * Returns true if this database can use functional indexes
 203          */
 204         function functionalIndexes() {
 205                 return false;
 206         }
 207
 208         /**
 209          * Return the last query that went through Database::query()
 210          * @return string
 211          */
 212         function lastQuery() { return $this->mLastQuery; }
 213
 214         /**
 215          * Is a connection to the database open?
 216          * @return bool
 217          */
 218         function isOpen() { return $this->mOpened; }
 219
 220         function setFlag( $flag ) {
 221                 $this->mFlags |= $flag;
 222         }
 223
 224         function clearFlag( $flag ) {
 225                 $this->mFlags &= ~$flag;
 226         }
 227
 228         function getFlag( $flag ) {
 229                 return !!($this->mFlags & $flag);
 230         }
 231
 232         /**
 233          * General read-only accessor
 234          */
 235         function getProperty( $name ) {
 236                 return $this->$name;
 237         }
 238
 239         function getWikiID() {
 240                 if( $this->mTablePrefix ) {
 241                         return "{$this->mDBname}-{$this->mTablePrefix}";
 242                 } else {
 243                         return $this->mDBname;
 244                 }
 245         }
 246
 247 #------------------------------------------------------------------------------
 248 # Other functions
 249 #------------------------------------------------------------------------------
 250
 251         /**@{{
 252          * Constructor.
 253          * @param string $server database server host
 254          * @param string $user database user name
 255          * @param string $password database user password
 256          * @param string $dbname database name
 257          * @param failFunction
 258          * @param $flags
 259          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 260          */
 261         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 262                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 263
 264                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 265                 # Can't get a reference if it hasn't been set yet
 266                 if ( !isset( $wgOut ) ) {
 267                         $wgOut = NULL;
 268                 }
 269
 270                 $this->mFailFunction = $failFunction;
 271                 $this->mFlags = $flags;
 272
 273                 if ( $this->mFlags & DBO_DEFAULT ) {
 274                         if ( $wgCommandLineMode ) {
 275                                 $this->mFlags &= ~DBO_TRX;
 276                         } else {
 277                                 $this->mFlags |= DBO_TRX;
 278                         }
 279                 }
 280
 281                 /*
 282                 // Faster read-only access
 283                 if ( wfReadOnly() ) {
 284                         $this->mFlags |= DBO_PERSISTENT;
 285                         $this->mFlags &= ~DBO_TRX;
 286                 }*/
 287
 288                 /** Get the default table prefix*/
 289                 if ( $tablePrefix == 'get from global' ) {
 290                         $this->mTablePrefix = $wgDBprefix;
 291                 } else {
 292                         $this->mTablePrefix = $tablePrefix;
 293                 }
 294
 295                 if ( $server ) {
 296                         $this->open( $server, $user, $password, $dbName );
 297                 }
 298         }
 299
 300         /**
 301          * @static
 302          * @param failFunction
 303          * @param $flags
 304          */
 305         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 306         {
 307                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 308         }
 309
 310         /**
 311          * Usually aborts on failure
 312          * If the failFunction is set to a non-zero integer, returns success
 313          */
 314         function open( $server, $user, $password, $dbName ) {
 315                 global $wguname, $wgAllDBsAreLocalhost;
 316                 wfProfileIn( __METHOD__ );
 317
 318                 # Test for missing mysql.so
 319                 # First try to load it
 320                 if (!@extension_loaded('mysql')) {
 321                         @dl('mysql.so');
 322                 }
 323
 324                 # Fail now
 325                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 326                 if ( !function_exists( 'mysql_connect' ) ) {
 327                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 328                 }
 329
 330                 # Debugging hack -- fake cluster
 331                 if ( $wgAllDBsAreLocalhost ) {
 332                         $realServer = 'localhost';
 333                 } else {
 334                         $realServer = $server;
 335                 }
 336                 $this->close();
 337                 $this->mServer = $server;
 338                 $this->mUser = $user;
 339                 $this->mPassword = $password;
 340                 $this->mDBname = $dbName;
 341
 342                 $success = false;
 343
 344                 wfProfileIn("dbconnect-$server");
 345
 346                 # The kernel's default SYN retransmission period is far too slow for us,
 347                 # so we use a short timeout plus a manual retry. Retrying means that a small
 348                 # but finite rate of SYN packet loss won't cause user-visible errors.
 349                 $this->mConn = false;
 350                 if ( ini_get( 'mysql.connect_timeout' ) <= 3 ) {
 351                         $numAttempts = 2;
 352                 } else {
 353                         $numAttempts = 1;
 354                 }
 355                 $this->installErrorHandler();
 356                 for ( $i = 0; $i < $numAttempts && !$this->mConn; $i++ ) {
 357                         if ( $i > 1 ) {
 358                                 usleep( 1000 );
 359                         }
 360                         if ( $this->mFlags & DBO_PERSISTENT ) {
 361                                 $this->mConn = mysql_pconnect( $realServer, $user, $password );
 362                         } else {
 363                                 # Create a new connection...
 364                                 $this->mConn = mysql_connect( $realServer, $user, $password, true );
 365                         }
 366                         if ($this->mConn === false) {
 367                                 #$iplus = $i + 1;
 368                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 369                         }
 370                 }
 371                 $phpError = $this->restoreErrorHandler();
 372                 # Always log connection errors
 373                 if ( !$this->mConn ) {
 374                         $error = $this->lastError();
 375                         if ( !$error ) {
 376                                 $error = $phpError;
 377                         }
 378                         wfLogDBError( "Error connecting to {$this->mServer}: $error\n" );
 379                         wfDebug( "DB connection error\n" );
 380                         wfDebug( "Server: $server, User: $user, Password: " .
 381                                 substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 382                         $success = false;
 383                 }
 384
 385                 wfProfileOut("dbconnect-$server");
 386
 387                 if ( $dbName != '' && $this->mConn !== false ) {
 388                         $success = @/**/mysql_select_db( $dbName, $this->mConn );
 389                         if ( !$success ) {
 390                                 $error = "Error selecting database $dbName on server {$this->mServer} " .
 391                                         "from client host {$wguname['nodename']}\n";
 392                                 wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 393                                 wfDebug( $error );
 394                         }
 395                 } else {
 396                         # Delay USE query
 397                         $success = (bool)$this->mConn;
 398                 }
 399
 400                 if ( $success ) {
 401                         $version = $this->getServerVersion();
 402                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 403                                 // Tell the server we're communicating with it in UTF-8.
 404                                 // This may engage various charset conversions.
 405                                 global $wgDBmysql5;
 406                                 if( $wgDBmysql5 ) {
 407                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 408                                 }
 409                                 // Turn off strict mode
 410                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 411                         }
 412
 413                         // Turn off strict mode if it is on
 414                 } else {
 415                         $this->reportConnectionError( $phpError );
 416                 }
 417
 418                 $this->mOpened = $success;
 419                 wfProfileOut( __METHOD__ );
 420                 return $success;
 421         }
 422         /**@}}*/
 423
 424         protected function installErrorHandler() {
 425                 $this->mPHPError = false;
 426                 set_error_handler( array( $this, 'connectionErrorHandler' ) );
 427         }
 428
 429         protected function restoreErrorHandler() {
 430                 restore_error_handler();
 431                 return $this->mPHPError;
 432         }
 433
 434         protected function connectionErrorHandler( $errno,  $errstr ) {
 435                 $this->mPHPError = $errstr;
 436         }
 437
 438         /**
 439          * Closes a database connection.
 440          * if it is open : commits any open transactions
 441          *
 442          * @return bool operation success. true if already closed.
 443          */
 444         function close()
 445         {
 446                 $this->mOpened = false;
 447                 if ( $this->mConn ) {
 448                         if ( $this->trxLevel() ) {
 449                                 $this->immediateCommit();
 450                         }
 451                         return mysql_close( $this->mConn );
 452                 } else {
 453                         return true;
 454                 }
 455         }
 456
 457         /**
 458          * @param string $error fallback error message, used if none is given by MySQL
 459          */
 460         function reportConnectionError( $error = 'Unknown error' ) {
 461                 $myError = $this->lastError();
 462                 if ( $myError ) {
 463                         $error = $myError;
 464                 }
 465
 466                 if ( $this->mFailFunction ) {
 467                         # Legacy error handling method
 468                         if ( !is_int( $this->mFailFunction ) ) {
 469                                 $ff = $this->mFailFunction;
 470                                 $ff( $this, $error );
 471                         }
 472                 } else {
 473                         # New method
 474                         throw new DBConnectionError( $this, $error );
 475                 }
 476         }
 477
 478         /**
 479          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 480          *
 481          * @param  $sql        String: SQL query
 482          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 483          *     comment (you can use __METHOD__ or add some extra info)
 484          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 485          *     maybe best to catch the exception instead?
 486          * @return true for a successful write query, ResultWrapper object for a successful read query,
 487          *     or false on failure if $tempIgnore set
 488          * @throws DBQueryError Thrown when the database returns an error of any kind
 489          */
 490         public function query( $sql, $fname = '', $tempIgnore = false ) {
 491                 global $wgProfiler;
 492
 493                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 494                 if ( isset( $wgProfiler ) ) {
 495                         # generalizeSQL will probably cut down the query to reasonable
 496                         # logging size most of the time. The substr is really just a sanity check.
 497
 498                         # Who's been wasting my precious column space? -- TS
 499                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 500
 501                         if ( $isMaster ) {
 502                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 503                                 $totalProf = 'Database::query-master';
 504                         } else {
 505                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 506                                 $totalProf = 'Database::query';
 507                         }
 508                         wfProfileIn( $totalProf );
 509                         wfProfileIn( $queryProf );
 510                 }
 511
 512                 $this->mLastQuery = $sql;
 513
 514                 # Add a comment for easy SHOW PROCESSLIST interpretation
 515                 #if ( $fname ) {
 516                         global $wgUser;
 517                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 518                                 $userName = $wgUser->getName();
 519                                 if ( mb_strlen( $userName ) > 15 ) {
 520                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 521                                 }
 522                                 $userName = str_replace( '/', '', $userName );
 523                         } else {
 524                                 $userName = '';
 525                         }
 526                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 527                 #} else {
 528                 #       $commentedSql = $sql;
 529                 #}
 530
 531                 # If DBO_TRX is set, start a transaction
 532                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 533                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 534                         // avoid establishing transactions for SHOW and SET statements too -
 535                         // that would delay transaction initializations to once connection
 536                         // is really used by application
 537                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 538                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 539                                 $this->begin();
 540                 }
 541
 542                 if ( $this->debug() ) {
 543                         $sqlx = substr( $commentedSql, 0, 500 );
 544                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 545                         if ( $isMaster ) {
 546                                 wfDebug( "SQL-master: $sqlx\n" );
 547                         } else {
 548                                 wfDebug( "SQL: $sqlx\n" );
 549                         }
 550                 }
 551
 552                 # Do the query and handle errors
 553                 $ret = $this->doQuery( $commentedSql );
 554
 555                 # Try reconnecting if the connection was lost
 556                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 557                         # Transaction is gone, like it or not
 558                         $this->mTrxLevel = 0;
 559                         wfDebug( "Connection lost, reconnecting...\n" );
 560                         if ( $this->ping() ) {
 561                                 wfDebug( "Reconnected\n" );
 562                                 $sqlx = substr( $commentedSql, 0, 500 );
 563                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 564                                 global $wgRequestTime;
 565                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 566                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 567                                 $ret = $this->doQuery( $commentedSql );
 568                         } else {
 569                                 wfDebug( "Failed\n" );
 570                         }
 571                 }
 572
 573                 if ( false === $ret ) {
 574                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 575                 }
 576
 577                 if ( isset( $wgProfiler ) ) {
 578                         wfProfileOut( $queryProf );
 579                         wfProfileOut( $totalProf );
 580                 }
 581                 return $this->resultObject( $ret );
 582         }
 583
 584         /**
 585          * The DBMS-dependent part of query()
 586          * @param  $sql String: SQL query.
 587          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 588          * @access private
 589          */
 590         /*private*/ function doQuery( $sql ) {
 591                 if( $this->bufferResults() ) {
 592                         $ret = mysql_query( $sql, $this->mConn );
 593                 } else {
 594                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 595                 }
 596                 return $ret;
 597         }
 598
 599         /**
 600          * @param $error
 601          * @param $errno
 602          * @param $sql
 603          * @param string $fname
 604          * @param bool $tempIgnore
 605          */
 606         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 607                 global $wgCommandLineMode;
 608                 # Ignore errors during error handling to avoid infinite recursion
 609                 $ignore = $this->ignoreErrors( true );
 610                 ++$this->mErrorCount;
 611
 612                 if( $ignore || $tempIgnore ) {
 613                         wfDebug("SQL ERROR (ignored): $error\n");
 614                         $this->ignoreErrors( $ignore );
 615                 } else {
 616                         $sql1line = str_replace( "\n", "\\n", $sql );
 617                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 618                         wfDebug("SQL ERROR: " . $error . "\n");
 619                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 620                 }
 621         }
 622
 623
 624         /**
 625          * Intended to be compatible with the PEAR::DB wrapper functions.
 626          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 627          *
 628          * ? = scalar value, quoted as necessary
 629          * ! = raw SQL bit (a function for instance)
 630          * & = filename; reads the file and inserts as a blob
 631          *     (we don't use this though...)
 632          */
 633         function prepare( $sql, $func = 'Database::prepare' ) {
 634                 /* MySQL doesn't support prepared statements (yet), so just
 635                    pack up the query for reference. We'll manually replace
 636                    the bits later. */
 637                 return array( 'query' => $sql, 'func' => $func );
 638         }
 639
 640         function freePrepared( $prepared ) {
 641                 /* No-op for MySQL */
 642         }
 643
 644         /**
 645          * Execute a prepared query with the various arguments
 646          * @param string $prepared the prepared sql
 647          * @param mixed $args Either an array here, or put scalars as varargs
 648          */
 649         function execute( $prepared, $args = null ) {
 650                 if( !is_array( $args ) ) {
 651                         # Pull the var args
 652                         $args = func_get_args();
 653                         array_shift( $args );
 654                 }
 655                 $sql = $this->fillPrepared( $prepared['query'], $args );
 656                 return $this->query( $sql, $prepared['func'] );
 657         }
 658
 659         /**
 660          * Prepare & execute an SQL statement, quoting and inserting arguments
 661          * in the appropriate places.
 662          * @param string $query
 663          * @param string $args ...
 664          */
 665         function safeQuery( $query, $args = null ) {
 666                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 667                 if( !is_array( $args ) ) {
 668                         # Pull the var args
 669                         $args = func_get_args();
 670                         array_shift( $args );
 671                 }
 672                 $retval = $this->execute( $prepared, $args );
 673                 $this->freePrepared( $prepared );
 674                 return $retval;
 675         }
 676
 677         /**
 678          * For faking prepared SQL statements on DBs that don't support
 679          * it directly.
 680          * @param string $preparedSql - a 'preparable' SQL statement
 681          * @param array $args - array of arguments to fill it with
 682          * @return string executable SQL
 683          */
 684         function fillPrepared( $preparedQuery, $args ) {
 685                 reset( $args );
 686                 $this->preparedArgs =& $args;
 687                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 688                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 689         }
 690
 691         /**
 692          * preg_callback func for fillPrepared()
 693          * The arguments should be in $this->preparedArgs and must not be touched
 694          * while we're doing this.
 695          *
 696          * @param array $matches
 697          * @return string
 698          * @private
 699          */
 700         function fillPreparedArg( $matches ) {
 701                 switch( $matches[1] ) {
 702                         case '\\?': return '?';
 703                         case '\\!': return '!';
 704                         case '\\&': return '&';
 705                 }
 706                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 707                 switch( $matches[1] ) {
 708                         case '?': return $this->addQuotes( $arg );
 709                         case '!': return $arg;
 710                         case '&':
 711                                 # return $this->addQuotes( file_get_contents( $arg ) );
 712                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 713                         default:
 714                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 715                 }
 716         }
 717
 718         /**#@+
 719          * @param mixed $res A SQL result
 720          */
 721         /**
 722          * Free a result object
 723          */
 724         function freeResult( $res ) {
 725                 if ( $res instanceof ResultWrapper ) {
 726                         $res = $res->result;
 727                 }
 728                 if ( !@/**/mysql_free_result( $res ) ) {
 729                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 730                 }
 731         }
 732
 733         /**
 734          * Fetch the next row from the given result object, in object form.
 735          * Fields can be retrieved with $row->fieldname, with fields acting like
 736          * member variables.
 737          *
 738          * @param $res SQL result object as returned from Database::query(), etc.
 739          * @return MySQL row object
 740          * @throws DBUnexpectedError Thrown if the database returns an error
 741          */
 742         function fetchObject( $res ) {
 743                 if ( $res instanceof ResultWrapper ) {
 744                         $res = $res->result;
 745                 }
 746                 @/**/$row = mysql_fetch_object( $res );
 747                 if( $this->lastErrno() ) {
 748                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 749                 }
 750                 return $row;
 751         }
 752
 753         /**
 754          * Fetch the next row from the given result object, in associative array
 755          * form.  Fields are retrieved with $row['fieldname'].
 756          *
 757          * @param $res SQL result object as returned from Database::query(), etc.
 758          * @return MySQL row object
 759          * @throws DBUnexpectedError Thrown if the database returns an error
 760          */
 761         function fetchRow( $res ) {
 762                 if ( $res instanceof ResultWrapper ) {
 763                         $res = $res->result;
 764                 }
 765                 @/**/$row = mysql_fetch_array( $res );
 766                 if ( $this->lastErrno() ) {
 767                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 768                 }
 769                 return $row;
 770         }
 771
 772         /**
 773          * Get the number of rows in a result object
 774          */
 775         function numRows( $res ) {
 776                 if ( $res instanceof ResultWrapper ) {
 777                         $res = $res->result;
 778                 }
 779                 @/**/$n = mysql_num_rows( $res );
 780                 if( $this->lastErrno() ) {
 781                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 782                 }
 783                 return $n;
 784         }
 785
 786         /**
 787          * Get the number of fields in a result object
 788          * See documentation for mysql_num_fields()
 789          */
 790         function numFields( $res ) {
 791                 if ( $res instanceof ResultWrapper ) {
 792                         $res = $res->result;
 793                 }
 794                 return mysql_num_fields( $res );
 795         }
 796
 797         /**
 798          * Get a field name in a result object
 799          * See documentation for mysql_field_name():
 800          * http://www.php.net/mysql_field_name
 801          */
 802         function fieldName( $res, $n ) {
 803                 if ( $res instanceof ResultWrapper ) {
 804                         $res = $res->result;
 805                 }
 806                 return mysql_field_name( $res, $n );
 807         }
 808
 809         /**
 810          * Get the inserted value of an auto-increment row
 811          *
 812          * The value inserted should be fetched from nextSequenceValue()
 813          *
 814          * Example:
 815          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 816          * $dbw->insert('page',array('page_id' => $id));
 817          * $id = $dbw->insertId();
 818          */
 819         function insertId() { return mysql_insert_id( $this->mConn ); }
 820
 821         /**
 822          * Change the position of the cursor in a result object
 823          * See mysql_data_seek()
 824          */
 825         function dataSeek( $res, $row ) {
 826                 if ( $res instanceof ResultWrapper ) {
 827                         $res = $res->result;
 828                 }
 829                 return mysql_data_seek( $res, $row );
 830         }
 831
 832         /**
 833          * Get the last error number
 834          * See mysql_errno()
 835          */
 836         function lastErrno() {
 837                 if ( $this->mConn ) {
 838                         return mysql_errno( $this->mConn );
 839                 } else {
 840                         return mysql_errno();
 841                 }
 842         }
 843
 844         /**
 845          * Get a description of the last error
 846          * See mysql_error() for more details
 847          */
 848         function lastError() {
 849                 if ( $this->mConn ) {
 850                         # Even if it's non-zero, it can still be invalid
 851                         wfSuppressWarnings();
 852                         $error = mysql_error( $this->mConn );
 853                         if ( !$error ) {
 854                                 $error = mysql_error();
 855                         }
 856                         wfRestoreWarnings();
 857                 } else {
 858                         $error = mysql_error();
 859                 }
 860                 if( $error ) {
 861                         $error .= ' (' . $this->mServer . ')';
 862                 }
 863                 return $error;
 864         }
 865         /**
 866          * Get the number of rows affected by the last write query
 867          * See mysql_affected_rows() for more details
 868          */
 869         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 870         /**#@-*/ // end of template : @param $result
 871
 872         /**
 873          * Simple UPDATE wrapper
 874          * Usually aborts on failure
 875          * If errors are explicitly ignored, returns success
 876          *
 877          * This function exists for historical reasons, Database::update() has a more standard
 878          * calling convention and feature set
 879          */
 880         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 881         {
 882                 $table = $this->tableName( $table );
 883                 $sql = "UPDATE $table SET $var = '" .
 884                   $this->strencode( $value ) . "' WHERE ($cond)";
 885                 return (bool)$this->query( $sql, $fname );
 886         }
 887
 888         /**
 889          * Simple SELECT wrapper, returns a single field, input must be encoded
 890          * Usually aborts on failure
 891          * If errors are explicitly ignored, returns FALSE on failure
 892          */
 893         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 894                 if ( !is_array( $options ) ) {
 895                         $options = array( $options );
 896                 }
 897                 $options['LIMIT'] = 1;
 898
 899                 $res = $this->select( $table, $var, $cond, $fname, $options );
 900                 if ( $res === false || !$this->numRows( $res ) ) {
 901                         return false;
 902                 }
 903                 $row = $this->fetchRow( $res );
 904                 if ( $row !== false ) {
 905                         $this->freeResult( $res );
 906                         return $row[0];
 907                 } else {
 908                         return false;
 909                 }
 910         }
 911
 912         /**
 913          * Returns an optional USE INDEX clause to go after the table, and a
 914          * string to go at the end of the query
 915          *
 916          * @private
 917          *
 918          * @param array $options an associative array of options to be turned into
 919          *              an SQL query, valid keys are listed in the function.
 920          * @return array
 921          */
 922         function makeSelectOptions( $options ) {
 923                 $preLimitTail = $postLimitTail = '';
 924                 $startOpts = '';
 925
 926                 $noKeyOptions = array();
 927                 foreach ( $options as $key => $option ) {
 928                         if ( is_numeric( $key ) ) {
 929                                 $noKeyOptions[$option] = true;
 930                         }
 931                 }
 932
 933                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 934                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 935                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 936
 937                 //if (isset($options['LIMIT'])) {
 938                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 939                 //              isset($options['OFFSET']) ? $options['OFFSET']
 940                 //              : false);
 941                 //}
 942
 943                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 944                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 945                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 946
 947                 # Various MySQL extensions
 948                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 949                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 950                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 951                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 952                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 953                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 954                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 955                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 956
 957                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 958                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 959                 } else {
 960                         $useIndex = '';
 961                 }
 962
 963                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 964         }
 965
 966         /**
 967          * SELECT wrapper
 968          *
 969          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 970          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 971          * @param mixed  $conds   Array or string, condition(s) for WHERE
 972          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 973          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 974          *                        see Database::makeSelectOptions code for list of supported stuff
 975          * @param array $join_conds Associative array of table join conditions (optional)
 976          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 977          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
 978          */
 979         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() )
 980         {
 981                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 982                 return $this->query( $sql, $fname );
 983         }
 984
 985         /**
 986          * SELECT wrapper
 987          *
 988          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 989          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 990          * @param mixed  $conds   Array or string, condition(s) for WHERE
 991          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 992          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 993          *                        see Database::makeSelectOptions code for list of supported stuff
 994          * @param array $join_conds Associative array of table join conditions (optional)
 995          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 996          * @return string, the SQL text
 997          */
 998         function selectSQLText( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() ) {
 999                 if( is_array( $vars ) ) {
1000                         $vars = implode( ',', $vars );
1001                 }
1002                 if( !is_array( $options ) ) {
1003                         $options = array( $options );
1004                 }
1005                 if( is_array( $table ) ) {
1006                         if ( !empty($join_conds) || ( isset( $options['USE INDEX'] ) && is_array( @$options['USE INDEX'] ) ) )
1007                                 $from = ' FROM ' . $this->tableNamesWithUseIndexOrJOIN( $table, @$options['USE INDEX'], $join_conds );
1008                         else
1009                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1010                 } elseif ($table!='') {
1011                         if ($table{0}==' ') {
1012                                 $from = ' FROM ' . $table;
1013                         } else {
1014                                 $from = ' FROM ' . $this->tableName( $table );
1015                         }
1016                 } else {
1017                         $from = '';
1018                 }
1019
1020                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
1021
1022                 if( !empty( $conds ) ) {
1023                         if ( is_array( $conds ) ) {
1024                                 $conds = $this->makeList( $conds, LIST_AND );
1025                         }
1026                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
1027                 } else {
1028                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
1029                 }
1030
1031                 if (isset($options['LIMIT']))
1032                         $sql = $this->limitResult($sql, $options['LIMIT'],
1033                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
1034                 $sql = "$sql $postLimitTail";
1035
1036                 if (isset($options['EXPLAIN'])) {
1037                         $sql = 'EXPLAIN ' . $sql;
1038                 }
1039                 return $sql;
1040         }
1041
1042         /**
1043          * Single row SELECT wrapper
1044          * Aborts or returns FALSE on error
1045          *
1046          * $vars: the selected variables
1047          * $conds: a condition map, terms are ANDed together.
1048          *   Items with numeric keys are taken to be literal conditions
1049          * Takes an array of selected variables, and a condition map, which is ANDed
1050          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1051          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1052          * $obj- >page_id is the ID of the Astronomy article
1053          *
1054          * @todo migrate documentation to phpdocumentor format
1055          */
1056         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array(), $join_conds = array() ) {
1057                 $options['LIMIT'] = 1;
1058                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1059                 if ( $res === false )
1060                         return false;
1061                 if ( !$this->numRows($res) ) {
1062                         $this->freeResult($res);
1063                         return false;
1064                 }
1065                 $obj = $this->fetchObject( $res );
1066                 $this->freeResult( $res );
1067                 return $obj;
1068
1069         }
1070
1071         /**
1072          * Estimate rows in dataset
1073          * Returns estimated count, based on EXPLAIN output
1074          * Takes same arguments as Database::select()
1075          */
1076
1077         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1078                 $options['EXPLAIN']=true;
1079                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1080                 if ( $res === false )
1081                         return false;
1082                 if (!$this->numRows($res)) {
1083                         $this->freeResult($res);
1084                         return 0;
1085                 }
1086
1087                 $rows=1;
1088
1089                 while( $plan = $this->fetchObject( $res ) ) {
1090                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1091                 }
1092
1093                 $this->freeResult($res);
1094                 return $rows;
1095         }
1096
1097
1098         /**
1099          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1100          * It's only slightly flawed. Don't use for anything important.
1101          *
1102          * @param string $sql A SQL Query
1103          * @static
1104          */
1105         static function generalizeSQL( $sql ) {
1106                 # This does the same as the regexp below would do, but in such a way
1107                 # as to avoid crashing php on some large strings.
1108                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1109
1110                 $sql = str_replace ( "\\\\", '', $sql);
1111                 $sql = str_replace ( "\\'", '', $sql);
1112                 $sql = str_replace ( "\\\"", '', $sql);
1113                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1114                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1115
1116                 # All newlines, tabs, etc replaced by single space
1117                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1118
1119                 # All numbers => N
1120                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1121
1122                 return $sql;
1123         }
1124
1125         /**
1126          * Determines whether a field exists in a table
1127          * Usually aborts on failure
1128          * If errors are explicitly ignored, returns NULL on failure
1129          */
1130         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1131                 $table = $this->tableName( $table );
1132                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1133                 if ( !$res ) {
1134                         return NULL;
1135                 }
1136
1137                 $found = false;
1138
1139                 while ( $row = $this->fetchObject( $res ) ) {
1140                         if ( $row->Field == $field ) {
1141                                 $found = true;
1142                                 break;
1143                         }
1144                 }
1145                 return $found;
1146         }
1147
1148         /**
1149          * Determines whether an index exists
1150          * Usually aborts on failure
1151          * If errors are explicitly ignored, returns NULL on failure
1152          */
1153         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1154                 $info = $this->indexInfo( $table, $index, $fname );
1155                 if ( is_null( $info ) ) {
1156                         return NULL;
1157                 } else {
1158                         return $info !== false;
1159                 }
1160         }
1161
1162
1163         /**
1164          * Get information about an index into an object
1165          * Returns false if the index does not exist
1166          */
1167         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1168                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1169                 # SHOW INDEX should work for 3.x and up:
1170                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1171                 $table = $this->tableName( $table );
1172                 $sql = 'SHOW INDEX FROM '.$table;
1173                 $res = $this->query( $sql, $fname );
1174                 if ( !$res ) {
1175                         return NULL;
1176                 }
1177
1178                 $result = array();
1179                 while ( $row = $this->fetchObject( $res ) ) {
1180                         if ( $row->Key_name == $index ) {
1181                                 $result[] = $row;
1182                         }
1183                 }
1184                 $this->freeResult($res);
1185
1186                 return empty($result) ? false : $result;
1187         }
1188
1189         /**
1190          * Query whether a given table exists
1191          */
1192         function tableExists( $table ) {
1193                 $table = $this->tableName( $table );
1194                 $old = $this->ignoreErrors( true );
1195                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1196                 $this->ignoreErrors( $old );
1197                 if( $res ) {
1198                         $this->freeResult( $res );
1199                         return true;
1200                 } else {
1201                         return false;
1202                 }
1203         }
1204
1205         /**
1206          * mysql_fetch_field() wrapper
1207          * Returns false if the field doesn't exist
1208          *
1209          * @param $table
1210          * @param $field
1211          */
1212         function fieldInfo( $table, $field ) {
1213                 $table = $this->tableName( $table );
1214                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1215                 $n = mysql_num_fields( $res->result );
1216                 for( $i = 0; $i < $n; $i++ ) {
1217                         $meta = mysql_fetch_field( $res->result, $i );
1218                         if( $field == $meta->name ) {
1219                                 return new MySQLField($meta);
1220                         }
1221                 }
1222                 return false;
1223         }
1224
1225         /**
1226          * mysql_field_type() wrapper
1227          */
1228         function fieldType( $res, $index ) {
1229                 if ( $res instanceof ResultWrapper ) {
1230                         $res = $res->result;
1231                 }
1232                 return mysql_field_type( $res, $index );
1233         }
1234
1235         /**
1236          * Determines if a given index is unique
1237          */
1238         function indexUnique( $table, $index ) {
1239                 $indexInfo = $this->indexInfo( $table, $index );
1240                 if ( !$indexInfo ) {
1241                         return NULL;
1242                 }
1243                 return !$indexInfo[0]->Non_unique;
1244         }
1245
1246         /**
1247          * INSERT wrapper, inserts an array into a table
1248          *
1249          * $a may be a single associative array, or an array of these with numeric keys, for
1250          * multi-row insert.
1251          *
1252          * Usually aborts on failure
1253          * If errors are explicitly ignored, returns success
1254          */
1255         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1256                 # No rows to insert, easy just return now
1257                 if ( !count( $a ) ) {
1258                         return true;
1259                 }
1260
1261                 $table = $this->tableName( $table );
1262                 if ( !is_array( $options ) ) {
1263                         $options = array( $options );
1264                 }
1265                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1266                         $multi = true;
1267                         $keys = array_keys( $a[0] );
1268                 } else {
1269                         $multi = false;
1270                         $keys = array_keys( $a );
1271                 }
1272
1273                 $sql = 'INSERT ' . implode( ' ', $options ) .
1274                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1275
1276                 if ( $multi ) {
1277                         $first = true;
1278                         foreach ( $a as $row ) {
1279                                 if ( $first ) {
1280                                         $first = false;
1281                                 } else {
1282                                         $sql .= ',';
1283                                 }
1284                                 $sql .= '(' . $this->makeList( $row ) . ')';
1285                         }
1286                 } else {
1287                         $sql .= '(' . $this->makeList( $a ) . ')';
1288                 }
1289                 return (bool)$this->query( $sql, $fname );
1290         }
1291
1292         /**
1293          * Make UPDATE options for the Database::update function
1294          *
1295          * @private
1296          * @param array $options The options passed to Database::update
1297          * @return string
1298          */
1299         function makeUpdateOptions( $options ) {
1300                 if( !is_array( $options ) ) {
1301                         $options = array( $options );
1302                 }
1303                 $opts = array();
1304                 if ( in_array( 'LOW_PRIORITY', $options ) )
1305                         $opts[] = $this->lowPriorityOption();
1306                 if ( in_array( 'IGNORE', $options ) )
1307                         $opts[] = 'IGNORE';
1308                 return implode(' ', $opts);
1309         }
1310
1311         /**
1312          * UPDATE wrapper, takes a condition array and a SET array
1313          *
1314          * @param string $table  The table to UPDATE
1315          * @param array  $values An array of values to SET
1316          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1317          * @param string $fname  The Class::Function calling this function
1318          *                       (for the log)
1319          * @param array  $options An array of UPDATE options, can be one or
1320          *                        more of IGNORE, LOW_PRIORITY
1321          * @return bool
1322          */
1323         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1324                 $table = $this->tableName( $table );
1325                 $opts = $this->makeUpdateOptions( $options );
1326                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1327                 if ( $conds != '*' ) {
1328                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1329                 }
1330                 return $this->query( $sql, $fname );
1331         }
1332
1333         /**
1334          * Makes an encoded list of strings from an array
1335          * $mode:
1336          *        LIST_COMMA         - comma separated, no field names
1337          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1338          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1339          *        LIST_SET           - comma separated with field names, like a SET clause
1340          *        LIST_NAMES         - comma separated field names
1341          */
1342         function makeList( $a, $mode = LIST_COMMA ) {
1343                 if ( !is_array( $a ) ) {
1344                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1345                 }
1346
1347                 $first = true;
1348                 $list = '';
1349                 foreach ( $a as $field => $value ) {
1350                         if ( !$first ) {
1351                                 if ( $mode == LIST_AND ) {
1352                                         $list .= ' AND ';
1353                                 } elseif($mode == LIST_OR) {
1354                                         $list .= ' OR ';
1355                                 } else {
1356                                         $list .= ',';
1357                                 }
1358                         } else {
1359                                 $first = false;
1360                         }
1361                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1362                                 $list .= "($value)";
1363                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1364                                 $list .= "$value";
1365                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1366                                 if( count( $value ) == 0 ) {
1367                                         throw new MWException( __METHOD__.': empty input' );
1368                                 } elseif( count( $value ) == 1 ) {
1369                                         // Special-case single values, as IN isn't terribly efficient
1370                                         // Don't necessarily assume the single key is 0; we don't
1371                                         // enforce linear numeric ordering on other arrays here.
1372                                         $value = array_values( $value );
1373                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1374                                 } else {
1375                                         $list .= $field." IN (".$this->makeList($value).") ";
1376                                 }
1377                         } elseif( is_null($value) ) {
1378                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1379                                         $list .= "$field IS ";
1380                                 } elseif ( $mode == LIST_SET ) {
1381                                         $list .= "$field = ";
1382                                 }
1383                                 $list .= 'NULL';
1384                         } else {
1385                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1386                                         $list .= "$field = ";
1387                                 }
1388                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1389                         }
1390                 }
1391                 return $list;
1392         }
1393
1394         /**
1395          * Change the current database
1396          */
1397         function selectDB( $db ) {
1398                 $this->mDBname = $db;
1399                 return mysql_select_db( $db, $this->mConn );
1400         }
1401
1402         /**
1403          * Get the current DB name
1404          */
1405         function getDBname() {
1406                 return $this->mDBname;
1407         }
1408
1409         /**
1410          * Get the server hostname or IP address
1411          */
1412         function getServer() {
1413                 return $this->mServer;
1414         }
1415
1416         /**
1417          * Format a table name ready for use in constructing an SQL query
1418          *
1419          * This does two important things: it quotes the table names to clean them up,
1420          * and it adds a table prefix if only given a table name with no quotes.
1421          *
1422          * All functions of this object which require a table name call this function
1423          * themselves. Pass the canonical name to such functions. This is only needed
1424          * when calling query() directly.
1425          *
1426          * @param string $name database table name
1427          * @return string full database name
1428          */
1429         function tableName( $name ) {
1430                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1431                 # Skip the entire process when we have a string quoted on both ends.
1432                 # Note that we check the end so that we will still quote any use of
1433                 # use of `database`.table. But won't break things if someone wants
1434                 # to query a database table with a dot in the name.
1435                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) return $name;
1436
1437                 # Lets test for any bits of text that should never show up in a table
1438                 # name. Basically anything like JOIN or ON which are actually part of
1439                 # SQL queries, but may end up inside of the table value to combine
1440                 # sql. Such as how the API is doing.
1441                 # Note that we use a whitespace test rather than a \b test to avoid
1442                 # any remote case where a word like on may be inside of a table name
1443                 # surrounded by symbols which may be considered word breaks.
1444                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) return $name;
1445
1446                 # Split database and table into proper variables.
1447                 # We reverse the explode so that database.table and table both output
1448                 # the correct table.
1449                 $dbDetails = array_reverse( explode( '.', $name, 2 ) );
1450                 if( isset( $dbDetails[1] ) ) @list( $table, $database ) = $dbDetails;
1451                 else                         @list( $table ) = $dbDetails;
1452                 $prefix = $this->mTablePrefix; # Default prefix
1453
1454                 # A database name has been specified in input. Quote the table name
1455                 # because we don't want any prefixes added.
1456                 if( isset($database) ) $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1457
1458                 # Note that we use the long format because php will complain in in_array if
1459                 # the input is not an array, and will complain in is_array if it is not set.
1460                 if( !isset( $database ) # Don't use shared database if pre selected.
1461                  && isset( $wgSharedDB ) # We have a shared database
1462                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1463                  && isset( $wgSharedTables )
1464                  && is_array( $wgSharedTables )
1465                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1466                         $database = $wgSharedDB;
1467                         $prefix   = isset( $wgSharedPrefix ) ? $wgSharedPrefix : $prefix;
1468                 }
1469
1470                 # Quote the $database and $table and apply the prefix if not quoted.
1471                 if( isset($database) ) $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1472                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1473
1474                 # Merge our database and table into our final table name.
1475                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1476
1477                 # We're finished, return.
1478                 return $tableName;
1479         }
1480
1481         /**
1482          * Fetch a number of table names into an array
1483          * This is handy when you need to construct SQL for joins
1484          *
1485          * Example:
1486          * extract($dbr->tableNames('user','watchlist'));
1487          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1488          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1489          */
1490         public function tableNames() {
1491                 $inArray = func_get_args();
1492                 $retVal = array();
1493                 foreach ( $inArray as $name ) {
1494                         $retVal[$name] = $this->tableName( $name );
1495                 }
1496                 return $retVal;
1497         }
1498
1499         /**
1500          * Fetch a number of table names into an zero-indexed numerical array
1501          * This is handy when you need to construct SQL for joins
1502          *
1503          * Example:
1504          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1505          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1506          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1507          */
1508         public function tableNamesN() {
1509                 $inArray = func_get_args();
1510                 $retVal = array();
1511                 foreach ( $inArray as $name ) {
1512                         $retVal[] = $this->tableName( $name );
1513                 }
1514                 return $retVal;
1515         }
1516
1517         /**
1518          * @private
1519          */
1520         function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1521                 $ret = array();
1522                 $retJOIN = array();
1523                 $use_index_safe = is_array($use_index) ? $use_index : array();
1524                 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1525                 foreach ( $tables as $table ) {
1526                         // Is there a JOIN and INDEX clause for this table?
1527                         if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1528                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1529                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1530                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1531                                 $retJOIN[] = $tableClause;
1532                         // Is there an INDEX clause?
1533                         } else if ( isset($use_index_safe[$table]) ) {
1534                                 $tableClause = $this->tableName( $table );
1535                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1536                                 $ret[] = $tableClause;
1537                         // Is there a JOIN clause?
1538                         } else if ( isset($join_conds_safe[$table]) ) {
1539                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1540                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1541                                 $retJOIN[] = $tableClause;
1542                         } else {
1543                                 $tableClause = $this->tableName( $table );
1544                                 $ret[] = $tableClause;
1545                         }
1546                 }
1547                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1548                 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1549                 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1550                 // Compile our final table clause
1551                 return implode(' ',array($straightJoins,$otherJoins) );
1552         }
1553
1554         /**
1555          * Wrapper for addslashes()
1556          * @param string $s String to be slashed.
1557          * @return string slashed string.
1558          */
1559         function strencode( $s ) {
1560                 return mysql_real_escape_string( $s, $this->mConn );
1561         }
1562
1563         /**
1564          * If it's a string, adds quotes and backslashes
1565          * Otherwise returns as-is
1566          */
1567         function addQuotes( $s ) {
1568                 if ( is_null( $s ) ) {
1569                         return 'NULL';
1570                 } else {
1571                         # This will also quote numeric values. This should be harmless,
1572                         # and protects against weird problems that occur when they really
1573                         # _are_ strings such as article titles and string->number->string
1574                         # conversion is not 1:1.
1575                         return "'" . $this->strencode( $s ) . "'";
1576                 }
1577         }
1578
1579         /**
1580          * Escape string for safe LIKE usage
1581          */
1582         function escapeLike( $s ) {
1583                 $s=$this->strencode( $s );
1584                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1585                 return $s;
1586         }
1587
1588         /**
1589          * Returns an appropriately quoted sequence value for inserting a new row.
1590          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1591          * subclass will return an integer, and save the value for insertId()
1592          */
1593         function nextSequenceValue( $seqName ) {
1594                 return NULL;
1595         }
1596
1597         /**
1598          * USE INDEX clause
1599          * PostgreSQL doesn't have them and returns ""
1600          */
1601         function useIndexClause( $index ) {
1602                 return "FORCE INDEX ($index)";
1603         }
1604
1605         /**
1606          * REPLACE query wrapper
1607          * PostgreSQL simulates this with a DELETE followed by INSERT
1608          * $row is the row to insert, an associative array
1609          * $uniqueIndexes is an array of indexes. Each element may be either a
1610          * field name or an array of field names
1611          *
1612          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1613          * However if you do this, you run the risk of encountering errors which wouldn't have
1614          * occurred in MySQL
1615          *
1616          * @todo migrate comment to phodocumentor format
1617          */
1618         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1619                 $table = $this->tableName( $table );
1620
1621                 # Single row case
1622                 if ( !is_array( reset( $rows ) ) ) {
1623                         $rows = array( $rows );
1624                 }
1625
1626                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1627                 $first = true;
1628                 foreach ( $rows as $row ) {
1629                         if ( $first ) {
1630                                 $first = false;
1631                         } else {
1632                                 $sql .= ',';
1633                         }
1634                         $sql .= '(' . $this->makeList( $row ) . ')';
1635                 }
1636                 return $this->query( $sql, $fname );
1637         }
1638
1639         /**
1640          * DELETE where the condition is a join
1641          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1642          *
1643          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1644          * join condition matches, set $conds='*'
1645          *
1646          * DO NOT put the join condition in $conds
1647          *
1648          * @param string $delTable The table to delete from.
1649          * @param string $joinTable The other table.
1650          * @param string $delVar The variable to join on, in the first table.
1651          * @param string $joinVar The variable to join on, in the second table.
1652          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1653          */
1654         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1655                 if ( !$conds ) {
1656                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1657                 }
1658
1659                 $delTable = $this->tableName( $delTable );
1660                 $joinTable = $this->tableName( $joinTable );
1661                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1662                 if ( $conds != '*' ) {
1663                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1664                 }
1665
1666                 return $this->query( $sql, $fname );
1667         }
1668
1669         /**
1670          * Returns the size of a text field, or -1 for "unlimited"
1671          */
1672         function textFieldSize( $table, $field ) {
1673                 $table = $this->tableName( $table );
1674                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1675                 $res = $this->query( $sql, 'Database::textFieldSize' );
1676                 $row = $this->fetchObject( $res );
1677                 $this->freeResult( $res );
1678
1679                 $m = array();
1680                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1681                         $size = $m[1];
1682                 } else {
1683                         $size = -1;
1684                 }
1685                 return $size;
1686         }
1687
1688         /**
1689          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1690          */
1691         function lowPriorityOption() {
1692                 return 'LOW_PRIORITY';
1693         }
1694
1695         /**
1696          * DELETE query wrapper
1697          *
1698          * Use $conds == "*" to delete all rows
1699          */
1700         function delete( $table, $conds, $fname = 'Database::delete' ) {
1701                 if ( !$conds ) {
1702                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1703                 }
1704                 $table = $this->tableName( $table );
1705                 $sql = "DELETE FROM $table";
1706                 if ( $conds != '*' ) {
1707                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1708                 }
1709                 return $this->query( $sql, $fname );
1710         }
1711
1712         /**
1713          * INSERT SELECT wrapper
1714          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1715          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1716          * $conds may be "*" to copy the whole table
1717          * srcTable may be an array of tables.
1718          */
1719         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1720                 $insertOptions = array(), $selectOptions = array() )
1721         {
1722                 $destTable = $this->tableName( $destTable );
1723                 if ( is_array( $insertOptions ) ) {
1724                         $insertOptions = implode( ' ', $insertOptions );
1725                 }
1726                 if( !is_array( $selectOptions ) ) {
1727                         $selectOptions = array( $selectOptions );
1728                 }
1729                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1730                 if( is_array( $srcTable ) ) {
1731                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1732                 } else {
1733                         $srcTable = $this->tableName( $srcTable );
1734                 }
1735                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1736                         " SELECT $startOpts " . implode( ',', $varMap ) .
1737                         " FROM $srcTable $useIndex ";
1738                 if ( $conds != '*' ) {
1739                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1740                 }
1741                 $sql .= " $tailOpts";
1742                 return $this->query( $sql, $fname );
1743         }
1744
1745         /**
1746          * Construct a LIMIT query with optional offset
1747          * This is used for query pages
1748          * $sql string SQL query we will append the limit too
1749          * $limit integer the SQL limit
1750          * $offset integer the SQL offset (default false)
1751          */
1752         function limitResult($sql, $limit, $offset=false) {
1753                 if( !is_numeric($limit) ) {
1754                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1755                 }
1756                 return "$sql LIMIT "
1757                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1758                                 . "{$limit} ";
1759         }
1760         function limitResultForUpdate($sql, $num) {
1761                 return $this->limitResult($sql, $num, 0);
1762         }
1763
1764         /**
1765          * Returns an SQL expression for a simple conditional.
1766          * Uses IF on MySQL.
1767          *
1768          * @param string $cond SQL expression which will result in a boolean value
1769          * @param string $trueVal SQL expression to return if true
1770          * @param string $falseVal SQL expression to return if false
1771          * @return string SQL fragment
1772          */
1773         function conditional( $cond, $trueVal, $falseVal ) {
1774                 return " IF($cond, $trueVal, $falseVal) ";
1775         }
1776
1777         /**
1778          * Returns a comand for str_replace function in SQL query.
1779          * Uses REPLACE() in MySQL
1780          *
1781          * @param string $orig String or column to modify
1782          * @param string $old String or column to seek
1783          * @param string $new String or column to replace with
1784          */
1785         function strreplace( $orig, $old, $new ) {
1786                 return "REPLACE({$orig}, {$old}, {$new})";
1787         }
1788
1789         /**
1790          * Determines if the last failure was due to a deadlock
1791          */
1792         function wasDeadlock() {
1793                 return $this->lastErrno() == 1213;
1794         }
1795
1796         /**
1797          * Perform a deadlock-prone transaction.
1798          *
1799          * This function invokes a callback function to perform a set of write
1800          * queries. If a deadlock occurs during the processing, the transaction
1801          * will be rolled back and the callback function will be called again.
1802          *
1803          * Usage:
1804          *   $dbw->deadlockLoop( callback, ... );
1805          *
1806          * Extra arguments are passed through to the specified callback function.
1807          *
1808          * Returns whatever the callback function returned on its successful,
1809          * iteration, or false on error, for example if the retry limit was
1810          * reached.
1811          */
1812         function deadlockLoop() {
1813                 $myFname = 'Database::deadlockLoop';
1814
1815                 $this->begin();
1816                 $args = func_get_args();
1817                 $function = array_shift( $args );
1818                 $oldIgnore = $this->ignoreErrors( true );
1819                 $tries = DEADLOCK_TRIES;
1820                 if ( is_array( $function ) ) {
1821                         $fname = $function[0];
1822                 } else {
1823                         $fname = $function;
1824                 }
1825                 do {
1826                         $retVal = call_user_func_array( $function, $args );
1827                         $error = $this->lastError();
1828                         $errno = $this->lastErrno();
1829                         $sql = $this->lastQuery();
1830
1831                         if ( $errno ) {
1832                                 if ( $this->wasDeadlock() ) {
1833                                         # Retry
1834                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1835                                 } else {
1836                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1837                                 }
1838                         }
1839                 } while( $this->wasDeadlock() && --$tries > 0 );
1840                 $this->ignoreErrors( $oldIgnore );
1841                 if ( $tries <= 0 ) {
1842                         $this->query( 'ROLLBACK', $myFname );
1843                         $this->reportQueryError( $error, $errno, $sql, $fname );
1844                         return false;
1845                 } else {
1846                         $this->query( 'COMMIT', $myFname );
1847                         return $retVal;
1848                 }
1849         }
1850
1851         /**
1852          * Do a SELECT MASTER_POS_WAIT()
1853          *
1854          * @param string $file the binlog file
1855          * @param string $pos the binlog position
1856          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1857          */
1858         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1859                 $fname = 'Database::masterPosWait';
1860                 wfProfileIn( $fname );
1861
1862                 # Commit any open transactions
1863                 if ( $this->mTrxLevel ) {
1864                         $this->immediateCommit();
1865                 }
1866
1867                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1868                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1869                         if ( $wait > $timeout * 1e6 ) {
1870                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1871                                 wfProfileOut( $fname );
1872                                 return -1;
1873                         } elseif ( $wait > 0 ) {
1874                                 wfDebug( "Fake slave waiting $wait us\n" );
1875                                 usleep( $wait );
1876                                 wfProfileOut( $fname );
1877                                 return 1;
1878                         } else {
1879                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1880                                 wfProfileOut( $fname );
1881                                 return 0;
1882                         }
1883                 }
1884
1885                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1886                 $encFile = $this->addQuotes( $pos->file );
1887                 $encPos = intval( $pos->pos );
1888                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1889                 $res = $this->doQuery( $sql );
1890                 if ( $res && $row = $this->fetchRow( $res ) ) {
1891                         $this->freeResult( $res );
1892                         wfProfileOut( $fname );
1893                         return $row[0];
1894                 } else {
1895                         wfProfileOut( $fname );
1896                         return false;
1897                 }
1898         }
1899
1900         /**
1901          * Get the position of the master from SHOW SLAVE STATUS
1902          */
1903         function getSlavePos() {
1904                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1905                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1906                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1907                         return $pos;
1908                 }
1909                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1910                 $row = $this->fetchObject( $res );
1911                 if ( $row ) {
1912                         return new MySQLMasterPos( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1913                 } else {
1914                         return false;
1915                 }
1916         }
1917
1918         /**
1919          * Get the position of the master from SHOW MASTER STATUS
1920          */
1921         function getMasterPos() {
1922                 if ( $this->mFakeMaster ) {
1923                         return new MySQLMasterPos( 'fake', microtime( true ) );
1924                 }
1925                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1926                 $row = $this->fetchObject( $res );
1927                 if ( $row ) {
1928                         return new MySQLMasterPos( $row->File, $row->Position );
1929                 } else {
1930                         return false;
1931                 }
1932         }
1933
1934         /**
1935          * Begin a transaction, committing any previously open transaction
1936          */
1937         function begin( $fname = 'Database::begin' ) {
1938                 $this->query( 'BEGIN', $fname );
1939                 $this->mTrxLevel = 1;
1940         }
1941
1942         /**
1943          * End a transaction
1944          */
1945         function commit( $fname = 'Database::commit' ) {
1946                 $this->query( 'COMMIT', $fname );
1947                 $this->mTrxLevel = 0;
1948         }
1949
1950         /**
1951          * Rollback a transaction.
1952          * No-op on non-transactional databases.
1953          */
1954         function rollback( $fname = 'Database::rollback' ) {
1955                 $this->query( 'ROLLBACK', $fname, true );
1956                 $this->mTrxLevel = 0;
1957         }
1958
1959         /**
1960          * Begin a transaction, committing any previously open transaction
1961          * @deprecated use begin()
1962          */
1963         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1964                 $this->begin();
1965         }
1966
1967         /**
1968          * Commit transaction, if one is open
1969          * @deprecated use commit()
1970          */
1971         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1972                 $this->commit();
1973         }
1974
1975         /**
1976          * Return MW-style timestamp used for MySQL schema
1977          */
1978         function timestamp( $ts=0 ) {
1979                 return wfTimestamp(TS_MW,$ts);
1980         }
1981
1982         /**
1983          * Local database timestamp format or null
1984          */
1985         function timestampOrNull( $ts = null ) {
1986                 if( is_null( $ts ) ) {
1987                         return null;
1988                 } else {
1989                         return $this->timestamp( $ts );
1990                 }
1991         }
1992
1993         /**
1994          * @todo document
1995          */
1996         function resultObject( $result ) {
1997                 if( empty( $result ) ) {
1998                         return false;
1999                 } elseif ( $result instanceof ResultWrapper ) {
2000                         return $result;
2001                 } elseif ( $result === true ) {
2002                         // Successful write query
2003                         return $result;
2004                 } else {
2005                         return new ResultWrapper( $this, $result );
2006                 }
2007         }
2008
2009         /**
2010          * Return aggregated value alias
2011          */
2012         function aggregateValue ($valuedata,$valuename='value') {
2013                 return $valuename;
2014         }
2015
2016         /**
2017          * @return string wikitext of a link to the server software's web site
2018          */
2019         function getSoftwareLink() {
2020                 return "[http://www.mysql.com/ MySQL]";
2021         }
2022
2023         /**
2024          * @return string Version information from the database
2025          */
2026         function getServerVersion() {
2027                 return mysql_get_server_info( $this->mConn );
2028         }
2029
2030         /**
2031          * Ping the server and try to reconnect if it there is no connection
2032          */
2033         function ping() {
2034                 if( !function_exists( 'mysql_ping' ) ) {
2035                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
2036                         return true;
2037                 }
2038                 $ping = mysql_ping( $this->mConn );
2039                 if ( $ping ) {
2040                         return true;
2041                 }
2042
2043                 // Need to reconnect manually in MySQL client 5.0.13+
2044                 if ( version_compare( mysql_get_client_info(), '5.0.13', '>=' ) ) {
2045                         mysql_close( $this->mConn );
2046                         $this->mOpened = false;
2047                         $this->mConn = false;
2048                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
2049                         return true;
2050                 }
2051                 return false;
2052         }
2053
2054         /**
2055          * Get slave lag.
2056          * At the moment, this will only work if the DB user has the PROCESS privilege
2057          */
2058         function getLag() {
2059                 if ( !is_null( $this->mFakeSlaveLag ) ) {
2060                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
2061                         return $this->mFakeSlaveLag;
2062                 }
2063                 $res = $this->query( 'SHOW PROCESSLIST' );
2064                 # Find slave SQL thread
2065                 while ( $row = $this->fetchObject( $res ) ) {
2066                         /* This should work for most situations - when default db
2067                          * for thread is not specified, it had no events executed,
2068                          * and therefore it doesn't know yet how lagged it is.
2069                          *
2070                          * Relay log I/O thread does not select databases.
2071                          */
2072                         if ( $row->User == 'system user' &&
2073                                 $row->State != 'Waiting for master to send event' &&
2074                                 $row->State != 'Connecting to master' &&
2075                                 $row->State != 'Queueing master event to the relay log' &&
2076                                 $row->State != 'Waiting for master update' &&
2077                                 $row->State != 'Requesting binlog dump'
2078                                 ) {
2079                                 # This is it, return the time (except -ve)
2080                                 if ( $row->Time > 0x7fffffff ) {
2081                                         return false;
2082                                 } else {
2083                                         return $row->Time;
2084                                 }
2085                         }
2086                 }
2087                 return false;
2088         }
2089
2090         /**
2091          * Get status information from SHOW STATUS in an associative array
2092          */
2093         function getStatus($which="%") {
2094                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2095                 $status = array();
2096                 while ( $row = $this->fetchObject( $res ) ) {
2097                         $status[$row->Variable_name] = $row->Value;
2098                 }
2099                 return $status;
2100         }
2101
2102         /**
2103          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2104          */
2105         function maxListLen() {
2106                 return 0;
2107         }
2108
2109         function encodeBlob($b) {
2110                 return $b;
2111         }
2112
2113         function decodeBlob($b) {
2114                 return $b;
2115         }
2116
2117         /**
2118          * Override database's default connection timeout.
2119          * May be useful for very long batch queries such as
2120          * full-wiki dumps, where a single query reads out
2121          * over hours or days.
2122          * @param int $timeout in seconds
2123          */
2124         public function setTimeout( $timeout ) {
2125                 $this->query( "SET net_read_timeout=$timeout" );
2126                 $this->query( "SET net_write_timeout=$timeout" );
2127         }
2128
2129         /**
2130          * Read and execute SQL commands from a file.
2131          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2132          * @param string $filename File name to open
2133          * @param callback $lineCallback Optional function called before reading each line
2134          * @param callback $resultCallback Optional function called for each MySQL result
2135          */
2136         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2137                 $fp = fopen( $filename, 'r' );
2138                 if ( false === $fp ) {
2139                         throw new MWException( "Could not open \"{$filename}\".\n" );
2140                 }
2141                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2142                 fclose( $fp );
2143                 return $error;
2144         }
2145
2146         /**
2147          * Read and execute commands from an open file handle
2148          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2149          * @param string $fp File handle
2150          * @param callback $lineCallback Optional function called before reading each line
2151          * @param callback $resultCallback Optional function called for each MySQL result
2152          */
2153         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2154                 $cmd = "";
2155                 $done = false;
2156                 $dollarquote = false;
2157
2158                 while ( ! feof( $fp ) ) {
2159                         if ( $lineCallback ) {
2160                                 call_user_func( $lineCallback );
2161                         }
2162                         $line = trim( fgets( $fp, 1024 ) );
2163                         $sl = strlen( $line ) - 1;
2164
2165                         if ( $sl < 0 ) { continue; }
2166                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2167
2168                         ## Allow dollar quoting for function declarations
2169                         if (substr($line,0,4) == '$mw$') {
2170                                 if ($dollarquote) {
2171                                         $dollarquote = false;
2172                                         $done = true;
2173                                 }
2174                                 else {
2175                                         $dollarquote = true;
2176                                 }
2177                         }
2178                         else if (!$dollarquote) {
2179                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2180                                         $done = true;
2181                                         $line = substr( $line, 0, $sl );
2182                                 }
2183                         }
2184
2185                         if ( '' != $cmd ) { $cmd .= ' '; }
2186                         $cmd .= "$line\n";
2187
2188                         if ( $done ) {
2189                                 $cmd = str_replace(';;', ";", $cmd);
2190                                 $cmd = $this->replaceVars( $cmd );
2191                                 $res = $this->query( $cmd, __METHOD__ );
2192                                 if ( $resultCallback ) {
2193                                         call_user_func( $resultCallback, $res, $this );
2194                                 }
2195
2196                                 if ( false === $res ) {
2197                                         $err = $this->lastError();
2198                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2199                                 }
2200
2201                                 $cmd = '';
2202                                 $done = false;
2203                         }
2204                 }
2205                 return true;
2206         }
2207
2208
2209         /**
2210          * Replace variables in sourced SQL
2211          */
2212         protected function replaceVars( $ins ) {
2213                 $varnames = array(
2214                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2215                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2216                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2217                 );
2218
2219                 // Ordinary variables
2220                 foreach ( $varnames as $var ) {
2221                         if( isset( $GLOBALS[$var] ) ) {
2222                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2223                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2224                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2225                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2226                         }
2227                 }
2228
2229                 // Table prefixes
2230                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-zA-Z_0-9]*)/',
2231                         array( &$this, 'tableNameCallback' ), $ins );
2232                 return $ins;
2233         }
2234
2235         /**
2236          * Table name callback
2237          * @private
2238          */
2239         protected function tableNameCallback( $matches ) {
2240                 return $this->tableName( $matches[1] );
2241         }
2242
2243         /*
2244          * Build a concatenation list to feed into a SQL query
2245         */
2246         function buildConcat( $stringList ) {
2247                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2248         }
2249
2250         /**
2251          * Acquire a lock
2252          *
2253          * Abstracted from Filestore::lock() so child classes can implement for
2254          * their own needs.
2255          *
2256          * @param string $lockName Name of lock to aquire
2257          * @param string $method Name of method calling us
2258          * @return bool
2259          */
2260         public function lock( $lockName, $method ) {
2261                 $lockName = $this->addQuotes( $lockName );
2262                 $result = $this->query( "SELECT GET_LOCK($lockName, 5) AS lockstatus", $method );
2263                 $row = $this->fetchObject( $result );
2264                 $this->freeResult( $result );
2265
2266                 if( $row->lockstatus == 1 ) {
2267                         return true;
2268                 } else {
2269                         wfDebug( __METHOD__." failed to acquire lock\n" );
2270                         return false;
2271                 }
2272         }
2273         /**
2274          * Release a lock.
2275          *
2276          * @todo fixme - Figure out a way to return a bool
2277          * based on successful lock release.
2278          *
2279          * @param string $lockName Name of lock to release
2280          * @param string $method Name of method calling us
2281          */
2282         public function unlock( $lockName, $method ) {
2283                 $lockName = $this->addQuotes( $lockName );
2284                 $result = $this->query( "SELECT RELEASE_LOCK($lockName)", $method );
2285                 $this->freeResult( $result );
2286         }
2287
2288         /**
2289          * Get search engine class. All subclasses of this
2290          * need to implement this if they wish to use searching.
2291          *
2292          * @return string
2293          */
2294         public function getSearchEngine() {
2295                 return "SearchMySQL";
2296         }
2297 }
2298
2299 /**
2300  * Database abstraction object for mySQL
2301  * Inherit all methods and properties of Database::Database()
2302  *
2303  * @ingroup Database
2304  * @see Database
2305  */
2306 class DatabaseMysql extends Database {
2307         # Inherit all
2308 }
2309
2310 /******************************************************************************
2311  * Utility classes
2312  *****************************************************************************/
2313
2314 /**
2315  * Utility class.
2316  * @ingroup Database
2317  */
2318 class DBObject {
2319         public $mData;
2320
2321         function DBObject($data) {
2322                 $this->mData = $data;
2323         }
2324
2325         function isLOB() {
2326                 return false;
2327         }
2328
2329         function data() {
2330                 return $this->mData;
2331         }
2332 }
2333
2334 /**
2335  * Utility class
2336  * @ingroup Database
2337  *
2338  * This allows us to distinguish a blob from a normal string and an array of strings
2339  */
2340 class Blob {
2341         private $mData;
2342         function __construct($data) {
2343                 $this->mData = $data;
2344         }
2345         function fetch() {
2346                 return $this->mData;
2347         }
2348 }
2349
2350 /**
2351  * Utility class.
2352  * @ingroup Database
2353  */
2354 class MySQLField {
2355         private $name, $tablename, $default, $max_length, $nullable,
2356                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2357         function __construct ($info) {
2358                 $this->name = $info->name;
2359                 $this->tablename = $info->table;
2360                 $this->default = $info->def;
2361                 $this->max_length = $info->max_length;
2362                 $this->nullable = !$info->not_null;
2363                 $this->is_pk = $info->primary_key;
2364                 $this->is_unique = $info->unique_key;
2365                 $this->is_multiple = $info->multiple_key;
2366                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2367                 $this->type = $info->type;
2368         }
2369
2370         function name() {
2371                 return $this->name;
2372         }
2373
2374         function tableName() {
2375                 return $this->tableName;
2376         }
2377
2378         function defaultValue() {
2379                 return $this->default;
2380         }
2381
2382         function maxLength() {
2383                 return $this->max_length;
2384         }
2385
2386         function nullable() {
2387                 return $this->nullable;
2388         }
2389
2390         function isKey() {
2391                 return $this->is_key;
2392         }
2393
2394         function isMultipleKey() {
2395                 return $this->is_multiple;
2396         }
2397
2398         function type() {
2399                 return $this->type;
2400         }
2401 }
2402
2403 /******************************************************************************
2404  * Error classes
2405  *****************************************************************************/
2406
2407 /**
2408  * Database error base class
2409  * @ingroup Database
2410  */
2411 class DBError extends MWException {
2412         public $db;
2413
2414         /**
2415          * Construct a database error
2416          * @param Database $db The database object which threw the error
2417          * @param string $error A simple error message to be used for debugging
2418          */
2419         function __construct( Database &$db, $error ) {
2420                 $this->db =& $db;
2421                 parent::__construct( $error );
2422         }
2423 }
2424
2425 /**
2426  * @ingroup Database
2427  */
2428 class DBConnectionError extends DBError {
2429         public $error;
2430
2431         function __construct( Database &$db, $error = 'unknown error' ) {
2432                 $msg = 'DB connection error';
2433                 if ( trim( $error ) != '' ) {
2434                         $msg .= ": $error";
2435                 }
2436                 $this->error = $error;
2437                 parent::__construct( $db, $msg );
2438         }
2439
2440         function useOutputPage() {
2441                 // Not likely to work
2442                 return false;
2443         }
2444
2445         function useMessageCache() {
2446                 // Not likely to work
2447                 return false;
2448         }
2449
2450         function getText() {
2451                 return $this->getMessage() . "\n";
2452         }
2453
2454         function getLogMessage() {
2455                 # Don't send to the exception log
2456                 return false;
2457         }
2458
2459         function getPageTitle() {
2460                 global $wgSitename;
2461                 return "$wgSitename has a problem";
2462         }
2463
2464         function getHTML() {
2465                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
2466                 global $wgSitename, $wgServer, $wgMessageCache;
2467
2468                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
2469                 # Hard coding strings instead.
2470
2471                 $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>";
2472                 $mainpage = 'Main Page';
2473                 $searchdisabled = <<<EOT
2474 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
2475 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
2476 EOT;
2477
2478                 $googlesearch = "
2479 <!-- SiteSearch Google -->
2480 <FORM method=GET action=\"http://www.google.com/search\">
2481 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
2482 <A HREF=\"http://www.google.com/\">
2483 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
2484 border=\"0\" ALT=\"Google\"></A>
2485 </td>
2486 <td>
2487 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
2488 <INPUT type=submit name=btnG VALUE=\"Google Search\">
2489 <font size=-1>
2490 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
2491 <input type='hidden' name='ie' value='$2'>
2492 <input type='hidden' name='oe' value='$2'>
2493 </font>
2494 </td></tr></TABLE>
2495 </FORM>
2496 <!-- SiteSearch Google -->";
2497                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
2498
2499                 # No database access
2500                 if ( is_object( $wgMessageCache ) ) {
2501                         $wgMessageCache->disable();
2502                 }
2503
2504                 if ( trim( $this->error ) == '' ) {
2505                         $this->error = $this->db->getProperty('mServer');
2506                 }
2507
2508                 $text = str_replace( '$1', $this->error, $noconnect );
2509
2510                 /*
2511                 if ( $GLOBALS['wgShowExceptionDetails'] ) {
2512                         $text .= '</p><p>Backtrace:</p><p>' .
2513                                 nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
2514                                 "</p>\n";
2515                 }*/
2516
2517                 if($wgUseFileCache) {
2518                         if($wgTitle) {
2519                                 $t =& $wgTitle;
2520                         } else {
2521                                 if($title) {
2522                                         $t = Title::newFromURL( $title );
2523                                 } elseif (@/**/$_REQUEST['search']) {
2524                                         $search = $_REQUEST['search'];
2525                                         return $searchdisabled .
2526                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
2527                                           $wgInputEncoding ), $googlesearch );
2528                                 } else {
2529                                         $t = Title::newFromText( $mainpage );
2530                                 }
2531                         }
2532
2533                         $cache = new HTMLFileCache( $t );
2534                         if( $cache->isFileCached() ) {
2535                                 // @todo, FIXME: $msg is not defined on the next line.
2536                                 $msg = '<p style="color: red"><b>'.$text."<br />\n" .
2537                                         $cachederror . "</b></p>\n";
2538
2539                                 $tag = '<div id="article">';
2540                                 $text = str_replace(
2541                                         $tag,
2542                                         $tag . $text,
2543                                         $cache->fetchPageText() );
2544                         }
2545                 }
2546
2547                 return $text;
2548         }
2549 }
2550
2551 /**
2552  * @ingroup Database
2553  */
2554 class DBQueryError extends DBError {
2555         public $error, $errno, $sql, $fname;
2556
2557         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
2558                 $message = "A database error has occurred\n" .
2559                   "Query: $sql\n" .
2560                   "Function: $fname\n" .
2561                   "Error: $errno $error\n";
2562
2563                 parent::__construct( $db, $message );
2564                 $this->error = $error;
2565                 $this->errno = $errno;
2566                 $this->sql = $sql;
2567                 $this->fname = $fname;
2568         }
2569
2570         function getText() {
2571                 if ( $this->useMessageCache() ) {
2572                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2573                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2574                 } else {
2575                         return $this->getMessage();
2576                 }
2577         }
2578
2579         function getSQL() {
2580                 global $wgShowSQLErrors;
2581                 if( !$wgShowSQLErrors ) {
2582                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2583                 } else {
2584                         return $this->sql;
2585                 }
2586         }
2587
2588         function getLogMessage() {
2589                 # Don't send to the exception log
2590                 return false;
2591         }
2592
2593         function getPageTitle() {
2594                 return $this->msg( 'databaseerror', 'Database error' );
2595         }
2596
2597         function getHTML() {
2598                 if ( $this->useMessageCache() ) {
2599                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2600                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2601                 } else {
2602                         return nl2br( htmlspecialchars( $this->getMessage() ) );
2603                 }
2604         }
2605 }
2606
2607 /**
2608  * @ingroup Database
2609  */
2610 class DBUnexpectedError extends DBError {}
2611
2612
2613 /**
2614  * Result wrapper for grabbing data queried by someone else
2615  * @ingroup Database
2616  */
2617 class ResultWrapper implements Iterator {
2618         var $db, $result, $pos = 0, $currentRow = null;
2619
2620         /**
2621          * Create a new result object from a result resource and a Database object
2622          */
2623         function ResultWrapper( $database, $result ) {
2624                 $this->db = $database;
2625                 if ( $result instanceof ResultWrapper ) {
2626                         $this->result = $result->result;
2627                 } else {
2628                         $this->result = $result;
2629                 }
2630         }
2631
2632         /**
2633          * Get the number of rows in a result object
2634          */
2635         function numRows() {
2636                 return $this->db->numRows( $this->result );
2637         }
2638
2639         /**
2640          * Fetch the next row from the given result object, in object form.
2641          * Fields can be retrieved with $row->fieldname, with fields acting like
2642          * member variables.
2643          *
2644          * @param $res SQL result object as returned from Database::query(), etc.
2645          * @return MySQL row object
2646          * @throws DBUnexpectedError Thrown if the database returns an error
2647          */
2648         function fetchObject() {
2649                 return $this->db->fetchObject( $this->result );
2650         }
2651
2652         /**
2653          * Fetch the next row from the given result object, in associative array
2654          * form.  Fields are retrieved with $row['fieldname'].
2655          *
2656          * @param $res SQL result object as returned from Database::query(), etc.
2657          * @return MySQL row object
2658          * @throws DBUnexpectedError Thrown if the database returns an error
2659          */
2660         function fetchRow() {
2661                 return $this->db->fetchRow( $this->result );
2662         }
2663
2664         /**
2665          * Free a result object
2666          */
2667         function free() {
2668                 $this->db->freeResult( $this->result );
2669                 unset( $this->result );
2670                 unset( $this->db );
2671         }
2672
2673         /**
2674          * Change the position of the cursor in a result object
2675          * See mysql_data_seek()
2676          */
2677         function seek( $row ) {
2678                 $this->db->dataSeek( $this->result, $row );
2679         }
2680
2681         /*********************
2682          * Iterator functions
2683          * Note that using these in combination with the non-iterator functions
2684          * above may cause rows to be skipped or repeated.
2685          */
2686
2687         function rewind() {
2688                 if ($this->numRows()) {
2689                         $this->db->dataSeek($this->result, 0);
2690                 }
2691                 $this->pos = 0;
2692                 $this->currentRow = null;
2693         }
2694
2695         function current() {
2696                 if ( is_null( $this->currentRow ) ) {
2697                         $this->next();
2698                 }
2699                 return $this->currentRow;
2700         }
2701
2702         function key() {
2703                 return $this->pos;
2704         }
2705
2706         function next() {
2707                 $this->pos++;
2708                 $this->currentRow = $this->fetchObject();
2709                 return $this->currentRow;
2710         }
2711
2712         function valid() {
2713                 return $this->current() !== false;
2714         }
2715 }
2716
2717 class MySQLMasterPos {
2718         var $file, $pos;
2719
2720         function __construct( $file, $pos ) {
2721                 $this->file = $file;
2722                 $this->pos = $pos;
2723         }
2724
2725         function __toString() {
2726                 return "{$this->file}/{$this->pos}";
2727         }
2728 }