includes/Database.php

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