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