includes/Database.php

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