includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  * @package MediaWiki
   6  */
   7
   8 /**
   9  * Depends on the CacheManager
  10  */
  11 require_once( 'CacheManager.php' );
  12
  13 /** See Database::makeList() */
  14 define( 'LIST_COMMA', 0 );
  15 define( 'LIST_AND', 1 );
  16 define( 'LIST_SET', 2 );
  17 define( 'LIST_NAMES', 3);
  18
  19 /** Number of times to re-try an operation in case of deadlock */
  20 define( 'DEADLOCK_TRIES', 4 );
  21 /** Minimum time to wait before retry, in microseconds */
  22 define( 'DEADLOCK_DELAY_MIN', 500000 );
  23 /** Maximum time to wait before retry */
  24 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  25
  26 class DBObject {
  27         var $mData;
  28
  29         function DBObject($data) {
  30                 $this->mData = $data;
  31         }
  32
  33         function isLOB() {
  34                 return false;
  35         }
  36
  37         function data() {
  38                 return $this->mData;
  39         }
  40 };
  41
  42 /**
  43  * Database abstraction object
  44  * @package MediaWiki
  45  */
  46 class Database {
  47
  48 #------------------------------------------------------------------------------
  49 # Variables
  50 #------------------------------------------------------------------------------
  51         /**#@+
  52          * @access private
  53          */
  54         var $mLastQuery = '';
  55
  56         var $mServer, $mUser, $mPassword, $mConn, $mDBname;
  57         var $mOut, $mOpened = false;
  58
  59         var $mFailFunction;
  60         var $mTablePrefix;
  61         var $mFlags;
  62         var $mTrxLevel = 0;
  63         var $mErrorCount = 0;
  64         /**#@-*/
  65
  66 #------------------------------------------------------------------------------
  67 # Accessors
  68 #------------------------------------------------------------------------------
  69         # These optionally set a variable and return the previous state
  70
  71         /**
  72          * Fail function, takes a Database as a parameter
  73          * Set to false for default, 1 for ignore errors
  74          */
  75         function failFunction( $function = NULL ) {
  76                 return wfSetVar( $this->mFailFunction, $function );
  77         }
  78
  79         /**
  80          * Output page, used for reporting errors
  81          * FALSE means discard output
  82          */
  83         function &setOutputPage( &$out ) {
  84                 $this->mOut =& $out;
  85         }
  86
  87         /**
  88          * Boolean, controls output of large amounts of debug information
  89          */
  90         function debug( $debug = NULL ) {
  91                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  92         }
  93
  94         /**
  95          * Turns buffering of SQL result sets on (true) or off (false).
  96          * Default is "on" and it should not be changed without good reasons.
  97          */
  98         function bufferResults( $buffer = NULL ) {
  99                 if ( is_null( $buffer ) ) {
 100                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 101                 } else {
 102                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 103                 }
 104         }
 105
 106         /**
 107          * Turns on (false) or off (true) the automatic generation and sending
 108          * of a "we're sorry, but there has been a database error" page on
 109          * database errors. Default is on (false). When turned off, the
 110          * code should use wfLastErrno() and wfLastError() to handle the
 111          * situation as appropriate.
 112          */
 113         function ignoreErrors( $ignoreErrors = NULL ) {
 114                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 115         }
 116
 117         /**
 118          * The current depth of nested transactions
 119          * @param integer $level
 120          */
 121         function trxLevel( $level = NULL ) {
 122                 return wfSetVar( $this->mTrxLevel, $level );
 123         }
 124
 125         /**
 126          * Number of errors logged, only useful when errors are ignored
 127          */
 128         function errorCount( $count = NULL ) {
 129                 return wfSetVar( $this->mErrorCount, $count );
 130         }
 131
 132         /**#@+
 133          * Get function
 134          */
 135         function lastQuery() { return $this->mLastQuery; }
 136         function isOpen() { return $this->mOpened; }
 137         /**#@-*/
 138
 139 #------------------------------------------------------------------------------
 140 # Other functions
 141 #------------------------------------------------------------------------------
 142
 143         /**#@+
 144          * @param string $server database server host
 145          * @param string $user database user name
 146          * @param string $password database user password
 147          * @param string $dbname database name
 148          */
 149
 150         /**
 151          * @param failFunction
 152          * @param $flags
 153          * @param string $tablePrefix Database table prefixes. By default use the prefix gave in LocalSettings.php
 154          */
 155         function Database( $server = false, $user = false, $password = false, $dbName = false,
 156                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 157
 158                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 159                 # Can't get a reference if it hasn't been set yet
 160                 if ( !isset( $wgOut ) ) {
 161                         $wgOut = NULL;
 162                 }
 163                 $this->mOut =& $wgOut;
 164
 165                 $this->mFailFunction = $failFunction;
 166                 $this->mFlags = $flags;
 167
 168                 if ( $this->mFlags & DBO_DEFAULT ) {
 169                         if ( $wgCommandLineMode ) {
 170                                 $this->mFlags &= ~DBO_TRX;
 171                         } else {
 172                                 $this->mFlags |= DBO_TRX;
 173                         }
 174                 }
 175
 176                 /*
 177                 // Faster read-only access
 178                 if ( wfReadOnly() ) {
 179                         $this->mFlags |= DBO_PERSISTENT;
 180                         $this->mFlags &= ~DBO_TRX;
 181                 }*/
 182
 183                 /** Get the default table prefix*/
 184                 if ( $tablePrefix == 'get from global' ) {
 185                         $this->mTablePrefix = $wgDBprefix;
 186                 } else {
 187                         $this->mTablePrefix = $tablePrefix;
 188                 }
 189
 190                 if ( $server ) {
 191                         $this->open( $server, $user, $password, $dbName );
 192                 }
 193         }
 194
 195         /**
 196          * @static
 197          * @param failFunction
 198          * @param $flags
 199          */
 200         function newFromParams( $server, $user, $password, $dbName,
 201                 $failFunction = false, $flags = 0 )
 202         {
 203                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 204         }
 205
 206         /**
 207          * Usually aborts on failure
 208          * If the failFunction is set to a non-zero integer, returns success
 209          */
 210         function open( $server, $user, $password, $dbName ) {
 211                 # Test for missing mysql.so
 212                 # First try to load it
 213                 if (!@extension_loaded('mysql')) {
 214                         @dl('mysql.so');
 215                 }
 216
 217                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 218                 if ( !function_exists( 'mysql_connect' ) ) {
 219                         die( "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 220                 }
 221
 222                 $this->close();
 223                 $this->mServer = $server;
 224                 $this->mUser = $user;
 225                 $this->mPassword = $password;
 226                 $this->mDBname = $dbName;
 227
 228                 $success = false;
 229
 230                 if ( $this->mFlags & DBO_PERSISTENT ) {
 231                         @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 232                 } else {
 233                         # Create a new connection...
 234                         @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 235                 }
 236
 237                 if ( $dbName != '' ) {
 238                         if ( $this->mConn !== false ) {
 239                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 240                                 if ( !$success ) {
 241                                         wfDebug( "Error selecting database \"$dbName\": " . $this->lastError() . "\n" );
 242                                 }
 243                         } else {
 244                                 wfDebug( "DB connection error\n" );
 245                                 wfDebug( "Server: $server, User: $user, Password: " .
 246                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 247                                 $success = false;
 248                         }
 249                 } else {
 250                         # Delay USE query
 251                         $success = (bool)$this->mConn;
 252                 }
 253
 254                 if ( !$success ) {
 255                         $this->reportConnectionError();
 256                         $this->close();
 257                 }
 258                 $this->mOpened = $success;
 259                 return $success;
 260         }
 261         /**#@-*/
 262
 263         /**
 264          * Closes a database connection.
 265          * if it is open : commits any open transactions
 266          *
 267          * @return bool operation success. true if already closed.
 268          */
 269         function close()
 270         {
 271                 $this->mOpened = false;
 272                 if ( $this->mConn ) {
 273                         if ( $this->trxLevel() ) {
 274                                 $this->immediateCommit();
 275                         }
 276                         return mysql_close( $this->mConn );
 277                 } else {
 278                         return true;
 279                 }
 280         }
 281
 282         /**
 283          * @access private
 284          * @param string $msg error message ?
 285          * @todo parameter $msg is not used
 286          */
 287         function reportConnectionError( $msg = '') {
 288                 if ( $this->mFailFunction ) {
 289                         if ( !is_int( $this->mFailFunction ) ) {
 290                                 $ff = $this->mFailFunction;
 291                                 $ff( $this, $this->lastError() );
 292                         }
 293                 } else {
 294                         wfEmergencyAbort( $this, mysql_error() );
 295                 }
 296         }
 297
 298         /**
 299          * Usually aborts on failure
 300          * If errors are explicitly ignored, returns success
 301          */
 302         function query( $sql, $fname = '', $tempIgnore = false ) {
 303                 global $wgProfiling, $wgCommandLineMode;
 304
 305                 if ( wfReadOnly() ) {
 306                         # This is a quick check for the most common kinds of write query used
 307                         # in MediaWiki, to provide extra safety in addition to UI-level checks.
 308                         # It is not intended to prevent every conceivable write query, or even
 309                         # to handle such queries gracefully.
 310                         if ( preg_match( '/^(update|insert|replace|delete)/i', $sql ) ) {
 311                                 wfDebug( "Write query from $fname blocked\n" );
 312                                 return false;
 313                         }
 314                 }
 315
 316                 if ( $wgProfiling ) {
 317                         # generalizeSQL will probably cut down the query to reasonable
 318                         # logging size most of the time. The substr is really just a sanity check.
 319                         $profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 320                         wfProfileIn( 'Database::query' );
 321                         wfProfileIn( $profName );
 322                 }
 323
 324                 $this->mLastQuery = $sql;
 325
 326                 # Add a comment for easy SHOW PROCESSLIST interpretation
 327                 if ( $fname ) {
 328                         $commentedSql = "/* $fname */ $sql";
 329                 } else {
 330                         $commentedSql = $sql;
 331                 }
 332
 333                 # If DBO_TRX is set, start a transaction
 334                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() && $sql != 'BEGIN' ) {
 335                         $this->begin();
 336                 }
 337
 338                 if ( $this->debug() ) {
 339                         $sqlx = substr( $commentedSql, 0, 500 );
 340                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 341                         wfDebug( "SQL: $sqlx\n" );
 342                 }
 343
 344                 # Do the query and handle errors
 345                 $ret = $this->doQuery( $commentedSql );
 346
 347                 # Try reconnecting if the connection was lost
 348                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 349                         # Transaction is gone, like it or not
 350                         $this->mTrxLevel = 0;
 351                         wfDebug( "Connection lost, reconnecting...\n" );
 352                         if ( $this->ping() ) {
 353                                 wfDebug( "Reconnected\n" );
 354                                 $ret = $this->doQuery( $commentedSql );
 355                         } else {
 356                                 wfDebug( "Failed\n" );
 357                         }
 358                 }
 359
 360                 if ( false === $ret ) {
 361                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 362                 }
 363
 364                 if ( $wgProfiling ) {
 365                         wfProfileOut( $profName );
 366                         wfProfileOut( 'Database::query' );
 367                 }
 368                 return $ret;
 369         }
 370
 371         /**
 372          * The DBMS-dependent part of query()
 373          * @param string $sql SQL query.
 374          */
 375         function doQuery( $sql ) {
 376                 if( $this->bufferResults() ) {
 377                         $ret = mysql_query( $sql, $this->mConn );
 378                 } else {
 379                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 380                 }
 381                 return $ret;
 382         }
 383
 384         /**
 385          * @param $error
 386          * @param $errno
 387          * @param $sql
 388          * @param string $fname
 389          * @param bool $tempIgnore
 390          */
 391         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 392                 global $wgCommandLineMode, $wgFullyInitialised;
 393                 # Ignore errors during error handling to avoid infinite recursion
 394                 $ignore = $this->ignoreErrors( true );
 395                 $this->mErrorCount ++;
 396
 397                 if( $ignore || $tempIgnore ) {
 398                         wfDebug("SQL ERROR (ignored): " . $error . "\n");
 399                 } else {
 400                         $sql1line = str_replace( "\n", "\\n", $sql );
 401                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 402                         wfDebug("SQL ERROR: " . $error . "\n");
 403                         if ( $wgCommandLineMode || !$this->mOut || empty( $wgFullyInitialised ) ) {
 404                                 $message = "A database error has occurred\n" .
 405                                   "Query: $sql\n" .
 406                                   "Function: $fname\n" .
 407                                   "Error: $errno $error\n";
 408                                 if ( !$wgCommandLineMode ) {
 409                                         $message = nl2br( $message );
 410                                 }
 411                                 wfDebugDieBacktrace( $message );
 412                         } else {
 413                                 // this calls wfAbruptExit()
 414                                 $this->mOut->databaseError( $fname, $sql, $error, $errno );
 415                         }
 416                 }
 417                 $this->ignoreErrors( $ignore );
 418         }
 419
 420
 421         /**
 422          * Intended to be compatible with the PEAR::DB wrapper functions.
 423          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 424          *
 425          * ? = scalar value, quoted as necessary
 426          * ! = raw SQL bit (a function for instance)
 427          * & = filename; reads the file and inserts as a blob
 428          *     (we don't use this though...)
 429          */
 430         function prepare( $sql, $func = 'Database::prepare' ) {
 431                 /* MySQL doesn't support prepared statements (yet), so just
 432                    pack up the query for reference. We'll manually replace
 433                    the bits later. */
 434                 return array( 'query' => $sql, 'func' => $func );
 435         }
 436
 437         function freePrepared( $prepared ) {
 438                 /* No-op for MySQL */
 439         }
 440
 441         /**
 442          * Execute a prepared query with the various arguments
 443          * @param string $prepared the prepared sql
 444          * @param mixed $args Either an array here, or put scalars as varargs
 445          */
 446         function execute( $prepared, $args = null ) {
 447                 if( !is_array( $args ) ) {
 448                         # Pull the var args
 449                         $args = func_get_args();
 450                         array_shift( $args );
 451                 }
 452                 $sql = $this->fillPrepared( $prepared['query'], $args );
 453                 return $this->query( $sql, $prepared['func'] );
 454         }
 455
 456         /**
 457          * Prepare & execute an SQL statement, quoting and inserting arguments
 458          * in the appropriate places.
 459          * @param string $query
 460          * @param string $args ...
 461          */
 462         function safeQuery( $query, $args = null ) {
 463                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 464                 if( !is_array( $args ) ) {
 465                         # Pull the var args
 466                         $args = func_get_args();
 467                         array_shift( $args );
 468                 }
 469                 $retval = $this->execute( $prepared, $args );
 470                 $this->freePrepared( $prepared );
 471                 return $retval;
 472         }
 473
 474         /**
 475          * For faking prepared SQL statements on DBs that don't support
 476          * it directly.
 477          * @param string $preparedSql - a 'preparable' SQL statement
 478          * @param array $args - array of arguments to fill it with
 479          * @return string executable SQL
 480          */
 481         function fillPrepared( $preparedQuery, $args ) {
 482                 $n = 0;
 483                 reset( $args );
 484                 $this->preparedArgs =& $args;
 485                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 486                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 487         }
 488
 489         /**
 490          * preg_callback func for fillPrepared()
 491          * The arguments should be in $this->preparedArgs and must not be touched
 492          * while we're doing this.
 493          *
 494          * @param array $matches
 495          * @return string
 496          * @access private
 497          */
 498         function fillPreparedArg( $matches ) {
 499                 switch( $matches[1] ) {
 500                         case '\\?': return '?';
 501                         case '\\!': return '!';
 502                         case '\\&': return '&';
 503                 }
 504                 list( $n, $arg ) = each( $this->preparedArgs );
 505                 switch( $matches[1] ) {
 506                         case '?': return $this->addQuotes( $arg );
 507                         case '!': return $arg;
 508                         case '&':
 509                                 # return $this->addQuotes( file_get_contents( $arg ) );
 510                                 wfDebugDieBacktrace( '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 511                         default:
 512                                 wfDebugDieBacktrace( 'Received invalid match. This should never happen!' );
 513                 }
 514         }
 515
 516         /**#@+
 517          * @param mixed $res A SQL result
 518          */
 519         /**
 520          * Free a result object
 521          */
 522         function freeResult( $res ) {
 523                 if ( !@/**/mysql_free_result( $res ) ) {
 524                         wfDebugDieBacktrace( "Unable to free MySQL result\n" );
 525                 }
 526         }
 527
 528         /**
 529          * Fetch the next row from the given result object, in object form
 530          */
 531         function fetchObject( $res ) {
 532                 @/**/$row = mysql_fetch_object( $res );
 533                 if( mysql_errno() ) {
 534                         wfDebugDieBacktrace( 'Error in fetchObject(): ' . htmlspecialchars( mysql_error() ) );
 535                 }
 536                 return $row;
 537         }
 538
 539         /**
 540          * Fetch the next row from the given result object
 541          * Returns an array
 542          */
 543         function fetchRow( $res ) {
 544                 @/**/$row = mysql_fetch_array( $res );
 545                 if (mysql_errno() ) {
 546                         wfDebugDieBacktrace( 'Error in fetchRow(): ' . htmlspecialchars( mysql_error() ) );
 547                 }
 548                 return $row;
 549         }
 550
 551         /**
 552          * Get the number of rows in a result object
 553          */
 554         function numRows( $res ) {
 555                 @/**/$n = mysql_num_rows( $res );
 556                 if( mysql_errno() ) {
 557                         wfDebugDieBacktrace( 'Error in numRows(): ' . htmlspecialchars( mysql_error() ) );
 558                 }
 559                 return $n;
 560         }
 561
 562         /**
 563          * Get the number of fields in a result object
 564          * See documentation for mysql_num_fields()
 565          */
 566         function numFields( $res ) { return mysql_num_fields( $res ); }
 567
 568         /**
 569          * Get a field name in a result object
 570          * See documentation for mysql_field_name()
 571          */
 572         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 573
 574         /**
 575          * Get the inserted value of an auto-increment row
 576          *
 577          * The value inserted should be fetched from nextSequenceValue()
 578          *
 579          * Example:
 580          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 581          * $dbw->insert('page',array('page_id' => $id));
 582          * $id = $dbw->insertId();
 583          */
 584         function insertId() { return mysql_insert_id( $this->mConn ); }
 585
 586         /**
 587          * Change the position of the cursor in a result object
 588          * See mysql_data_seek()
 589          */
 590         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 591
 592         /**
 593          * Get the last error number
 594          * See mysql_errno()
 595          */
 596         function lastErrno() {
 597                 if ( $this->mConn ) {
 598                         return mysql_errno( $this->mConn );
 599                 } else {
 600                         return mysql_errno();
 601                 }
 602         }
 603
 604         /**
 605          * Get a description of the last error
 606          * See mysql_error() for more details
 607          */
 608         function lastError() {
 609                 if ( $this->mConn ) {
 610                         $error = mysql_error( $this->mConn );
 611                 } else {
 612                         $error = mysql_error();
 613                 }
 614                 if( $error ) {
 615                         $error .= ' (' . $this->mServer . ')';
 616                 }
 617                 return $error;
 618         }
 619         /**
 620          * Get the number of rows affected by the last write query
 621          * See mysql_affected_rows() for more details
 622          */
 623         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 624         /**#@-*/ // end of template : @param $result
 625
 626         /**
 627          * Simple UPDATE wrapper
 628          * Usually aborts on failure
 629          * If errors are explicitly ignored, returns success
 630          *
 631          * This function exists for historical reasons, Database::update() has a more standard
 632          * calling convention and feature set
 633          */
 634         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 635         {
 636                 $table = $this->tableName( $table );
 637                 $sql = "UPDATE $table SET $var = '" .
 638                   $this->strencode( $value ) . "' WHERE ($cond)";
 639                 return (bool)$this->query( $sql, DB_MASTER, $fname );
 640         }
 641
 642         /**
 643          * Simple SELECT wrapper, returns a single field, input must be encoded
 644          * Usually aborts on failure
 645          * If errors are explicitly ignored, returns FALSE on failure
 646          */
 647         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 648                 if ( !is_array( $options ) ) {
 649                         $options = array( $options );
 650                 }
 651                 $options['LIMIT'] = 1;
 652
 653                 $res = $this->select( $table, $var, $cond, $fname, $options );
 654                 if ( $res === false || !$this->numRows( $res ) ) {
 655                         return false;
 656                 }
 657                 $row = $this->fetchRow( $res );
 658                 if ( $row !== false ) {
 659                         $this->freeResult( $res );
 660                         return $row[0];
 661                 } else {
 662                         return false;
 663                 }
 664         }
 665
 666         /**
 667          * Returns an optional USE INDEX clause to go after the table, and a
 668          * string to go at the end of the query
 669          *
 670          * @access private
 671          *
 672          * @param array $options an associative array of options to be turned into
 673          *              an SQL query, valid keys are listed in the function.
 674          * @return array
 675          */
 676         function makeSelectOptions( $options ) {
 677                 $tailOpts = '';
 678
 679                 if ( isset( $options['GROUP BY'] ) ) {
 680                         $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 681                 }
 682                 if ( isset( $options['ORDER BY'] ) ) {
 683                         $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 684                 }
 685
 686                 if ( is_numeric( array_search( 'FOR UPDATE', $options ) ) ) {
 687                         $tailOpts .= ' FOR UPDATE';
 688                 }
 689
 690                 if ( is_numeric( array_search( 'LOCK IN SHARE MODE', $options ) ) ) {
 691                         $tailOpts .= ' LOCK IN SHARE MODE';
 692                 }
 693
 694                 if ( isset( $options['USE INDEX'] ) ) {
 695                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 696                 } else {
 697                         $useIndex = '';
 698                 }
 699                 return array( $useIndex, $tailOpts );
 700         }
 701
 702         /**
 703          * SELECT wrapper
 704          */
 705         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
 706         {
 707                 if( is_array( $vars ) ) {
 708                         $vars = implode( ',', $vars );
 709                 }
 710                 if( !is_array( $options ) ) {
 711                         $options = array( $options );
 712                 }
 713                 if( is_array( $table ) ) {
 714                         $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 715                 } elseif ($table!='') {
 716                         $from = ' FROM ' .$this->tableName( $table );
 717                 } else {
 718                         $from = '';
 719                 }
 720
 721                 list( $useIndex, $tailOpts ) = $this->makeSelectOptions( $options );
 722
 723                 if( !empty( $conds ) ) {
 724                         if ( is_array( $conds ) ) {
 725                                 $conds = $this->makeList( $conds, LIST_AND );
 726                         }
 727                         $sql = "SELECT $vars $from $useIndex WHERE $conds $tailOpts";
 728                 } else {
 729                         $sql = "SELECT $vars $from $useIndex $tailOpts";
 730                 }
 731                 if (isset($options['LIMIT'])) {
 732                         $sql = $this->limitResult($sql, $options['LIMIT'], isset($options['OFFSET']) ? $options['OFFSET'] : false);
 733                 }
 734                 return $this->query( $sql, $fname );
 735         }
 736
 737         /**
 738          * Single row SELECT wrapper
 739          * Aborts or returns FALSE on error
 740          *
 741          * $vars: the selected variables
 742          * $conds: a condition map, terms are ANDed together.
 743          *   Items with numeric keys are taken to be literal conditions
 744          * Takes an array of selected variables, and a condition map, which is ANDed
 745          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 746          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 747          * $obj- >page_id is the ID of the Astronomy article
 748          *
 749          * @todo migrate documentation to phpdocumentor format
 750          */
 751         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
 752                 $options['LIMIT'] = 1;
 753                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 754                 if ( $res === false )
 755                         return false;
 756                 if ( !$this->numRows($res) ) {
 757                         $this->freeResult($res);
 758                         return false;
 759                 }
 760                 $obj = $this->fetchObject( $res );
 761                 $this->freeResult( $res );
 762                 return $obj;
 763
 764         }
 765
 766         /**
 767          * Removes most variables from an SQL query and replaces them with X or N for numbers.
 768          * It's only slightly flawed. Don't use for anything important.
 769          *
 770          * @param string $sql A SQL Query
 771          * @static
 772          */
 773         function generalizeSQL( $sql ) {
 774                 # This does the same as the regexp below would do, but in such a way
 775                 # as to avoid crashing php on some large strings.
 776                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
 777
 778                 $sql = str_replace ( "\\\\", '', $sql);
 779                 $sql = str_replace ( "\\'", '', $sql);
 780                 $sql = str_replace ( "\\\"", '', $sql);
 781                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
 782                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
 783
 784                 # All newlines, tabs, etc replaced by single space
 785                 $sql = preg_replace ( "/\s+/", ' ', $sql);
 786
 787                 # All numbers => N
 788                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
 789
 790                 return $sql;
 791         }
 792
 793         /**
 794          * Determines whether a field exists in a table
 795          * Usually aborts on failure
 796          * If errors are explicitly ignored, returns NULL on failure
 797          */
 798         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
 799                 $table = $this->tableName( $table );
 800                 $res = $this->query( 'DESCRIBE '.$table, DB_SLAVE, $fname );
 801                 if ( !$res ) {
 802                         return NULL;
 803                 }
 804
 805                 $found = false;
 806
 807                 while ( $row = $this->fetchObject( $res ) ) {
 808                         if ( $row->Field == $field ) {
 809                                 $found = true;
 810                                 break;
 811                         }
 812                 }
 813                 return $found;
 814         }
 815
 816         /**
 817          * Determines whether an index exists
 818          * Usually aborts on failure
 819          * If errors are explicitly ignored, returns NULL on failure
 820          */
 821         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
 822                 $info = $this->indexInfo( $table, $index, $fname );
 823                 if ( is_null( $info ) ) {
 824                         return NULL;
 825                 } else {
 826                         return $info !== false;
 827                 }
 828         }
 829
 830
 831         /**
 832          * Get information about an index into an object
 833          * Returns false if the index does not exist
 834          */
 835         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
 836                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 837                 # SHOW INDEX should work for 3.x and up:
 838                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 839                 $table = $this->tableName( $table );
 840                 $sql = 'SHOW INDEX FROM '.$table;
 841                 $res = $this->query( $sql, $fname );
 842                 if ( !$res ) {
 843                         return NULL;
 844                 }
 845
 846                 while ( $row = $this->fetchObject( $res ) ) {
 847                         if ( $row->Key_name == $index ) {
 848                                 return $row;
 849                         }
 850                 }
 851                 return false;
 852         }
 853
 854         /**
 855          * Query whether a given table exists
 856          */
 857         function tableExists( $table ) {
 858                 $table = $this->tableName( $table );
 859                 $old = $this->ignoreErrors( true );
 860                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
 861                 $this->ignoreErrors( $old );
 862                 if( $res ) {
 863                         $this->freeResult( $res );
 864                         return true;
 865                 } else {
 866                         return false;
 867                 }
 868         }
 869
 870         /**
 871          * mysql_fetch_field() wrapper
 872          * Returns false if the field doesn't exist
 873          *
 874          * @param $table
 875          * @param $field
 876          */
 877         function fieldInfo( $table, $field ) {
 878                 $table = $this->tableName( $table );
 879                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
 880                 $n = mysql_num_fields( $res );
 881                 for( $i = 0; $i < $n; $i++ ) {
 882                         $meta = mysql_fetch_field( $res, $i );
 883                         if( $field == $meta->name ) {
 884                                 return $meta;
 885                         }
 886                 }
 887                 return false;
 888         }
 889
 890         /**
 891          * mysql_field_type() wrapper
 892          */
 893         function fieldType( $res, $index ) {
 894                 return mysql_field_type( $res, $index );
 895         }
 896
 897         /**
 898          * Determines if a given index is unique
 899          */
 900         function indexUnique( $table, $index ) {
 901                 $indexInfo = $this->indexInfo( $table, $index );
 902                 if ( !$indexInfo ) {
 903                         return NULL;
 904                 }
 905                 return !$indexInfo->Non_unique;
 906         }
 907
 908         /**
 909          * INSERT wrapper, inserts an array into a table
 910          *
 911          * $a may be a single associative array, or an array of these with numeric keys, for
 912          * multi-row insert.
 913          *
 914          * Usually aborts on failure
 915          * If errors are explicitly ignored, returns success
 916          */
 917         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
 918                 # No rows to insert, easy just return now
 919                 if ( !count( $a ) ) {
 920                         return true;
 921                 }
 922
 923                 $table = $this->tableName( $table );
 924                 if ( !is_array( $options ) ) {
 925                         $options = array( $options );
 926                 }
 927                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 928                         $multi = true;
 929                         $keys = array_keys( $a[0] );
 930                 } else {
 931                         $multi = false;
 932                         $keys = array_keys( $a );
 933                 }
 934
 935                 $sql = 'INSERT ' . implode( ' ', $options ) .
 936                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 937
 938                 if ( $multi ) {
 939                         $first = true;
 940                         foreach ( $a as $row ) {
 941                                 if ( $first ) {
 942                                         $first = false;
 943                                 } else {
 944                                         $sql .= ',';
 945                                 }
 946                                 $sql .= '(' . $this->makeList( $row ) . ')';
 947                         }
 948                 } else {
 949                         $sql .= '(' . $this->makeList( $a ) . ')';
 950                 }
 951                 return (bool)$this->query( $sql, $fname );
 952         }
 953
 954         /**
 955          * Make UPDATE options for the Database::update function
 956          *
 957          * @access private
 958          * @param array $options The options passed to Database::update
 959          * @return string
 960          */
 961         function makeUpdateOptions( $options ) {
 962                 if( !is_array( $options ) ) {
 963                         wfDebugDieBacktrace( 'makeUpdateOptions given non-array' );
 964                 }
 965                 $opts = array();
 966                 if ( in_array( 'LOW_PRIORITY', $options ) )
 967                         $opts[] = $this->lowPriorityOption();
 968                 if ( in_array( 'IGNORE', $options ) )
 969                         $opts[] = 'IGNORE';
 970                 return implode(' ', $opts);
 971         }
 972
 973         /**
 974          * UPDATE wrapper, takes a condition array and a SET array
 975          *
 976          * @param string $table  The table to UPDATE
 977          * @param array  $values An array of values to SET
 978          * @param array  $conds  An array of conditions (WHERE)
 979          * @param string $fname  The Class::Function calling this function
 980          *                       (for the log)
 981          * @param array  $options An array of UPDATE options, can be one or
 982          *                        more of IGNORE, LOW_PRIORITY
 983          */
 984         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
 985                 $table = $this->tableName( $table );
 986                 $opts = $this->makeUpdateOptions( $options );
 987                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
 988                 if ( $conds != '*' ) {
 989                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
 990                 }
 991                 $this->query( $sql, $fname );
 992         }
 993
 994         /**
 995          * Makes a wfStrencoded list from an array
 996          * $mode: LIST_COMMA         - comma separated, no field names
 997          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
 998          *        LIST_SET           - comma separated with field names, like a SET clause
 999          *        LIST_NAMES         - comma separated field names
1000          */
1001         function makeList( $a, $mode = LIST_COMMA ) {
1002                 if ( !is_array( $a ) ) {
1003                         wfDebugDieBacktrace( 'Database::makeList called with incorrect parameters' );
1004                 }
1005
1006                 $first = true;
1007                 $list = '';
1008                 foreach ( $a as $field => $value ) {
1009                         if ( !$first ) {
1010                                 if ( $mode == LIST_AND ) {
1011                                         $list .= ' AND ';
1012                                 } else {
1013                                         $list .= ',';
1014                                 }
1015                         } else {
1016                                 $first = false;
1017                         }
1018                         if ( $mode == LIST_AND && is_numeric( $field ) ) {
1019                                 $list .= "($value)";
1020                         } elseif ( $mode == LIST_AND && is_array ($value) ) {
1021                                 $list .= $field." IN (".$this->makeList($value).") ";
1022                         } else {
1023                                 if ( $mode == LIST_AND || $mode == LIST_SET ) {
1024                                         $list .= "$field = ";
1025                                 }
1026                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1027                         }
1028                 }
1029                 return $list;
1030         }
1031
1032         /**
1033          * Change the current database
1034          */
1035         function selectDB( $db ) {
1036                 $this->mDBname = $db;
1037                 return mysql_select_db( $db, $this->mConn );
1038         }
1039
1040         /**
1041          * Starts a timer which will kill the DB thread after $timeout seconds
1042          */
1043         function startTimer( $timeout ) {
1044                 global $IP;
1045                 if( function_exists( 'mysql_thread_id' ) ) {
1046                         # This will kill the query if it's still running after $timeout seconds.
1047                         $tid = mysql_thread_id( $this->mConn );
1048                         exec( "php $IP/includes/killthread.php $timeout $tid &>/dev/null &" );
1049                 }
1050         }
1051
1052         /**
1053          * Stop a timer started by startTimer()
1054          * Currently unimplemented.
1055          *
1056          */
1057         function stopTimer() { }
1058
1059         /**
1060          * Format a table name ready for use in constructing an SQL query
1061          *
1062          * This does two important things: it quotes table names which as necessary,
1063          * and it adds a table prefix if there is one.
1064          *
1065          * All functions of this object which require a table name call this function
1066          * themselves. Pass the canonical name to such functions. This is only needed
1067          * when calling query() directly.
1068          *
1069          * @param string $name database table name
1070          */
1071         function tableName( $name ) {
1072                 global $wgSharedDB;
1073                 # Skip quoted literals
1074                 if ( $name{0} != '`' ) {
1075                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1076                                 $name = "{$this->mTablePrefix}$name";
1077                         }
1078                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1079                                 $name = "`$wgSharedDB`.`$name`";
1080                         } else {
1081                                 # Standard quoting
1082                                 $name = "`$name`";
1083                         }
1084                 }
1085                 return $name;
1086         }
1087
1088         /**
1089          * Fetch a number of table names into an array
1090          * This is handy when you need to construct SQL for joins
1091          *
1092          * Example:
1093          * extract($dbr->tableNames('user','watchlist'));
1094          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1095          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1096          */
1097         function tableNames() {
1098                 $inArray = func_get_args();
1099                 $retVal = array();
1100                 foreach ( $inArray as $name ) {
1101                         $retVal[$name] = $this->tableName( $name );
1102                 }
1103                 return $retVal;
1104         }
1105
1106         /**
1107          * Wrapper for addslashes()
1108          * @param string $s String to be slashed.
1109          * @return string slashed string.
1110          */
1111         function strencode( $s ) {
1112                 return addslashes( $s );
1113         }
1114
1115         /**
1116          * If it's a string, adds quotes and backslashes
1117          * Otherwise returns as-is
1118          */
1119         function addQuotes( $s ) {
1120                 if ( is_null( $s ) ) {
1121                         return 'NULL';
1122                 } else {
1123                         # This will also quote numeric values. This should be harmless,
1124                         # and protects against weird problems that occur when they really
1125                         # _are_ strings such as article titles and string->number->string
1126                         # conversion is not 1:1.
1127                         return "'" . $this->strencode( $s ) . "'";
1128                 }
1129         }
1130
1131         /**
1132          * Returns an appropriately quoted sequence value for inserting a new row.
1133          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1134          * subclass will return an integer, and save the value for insertId()
1135          */
1136         function nextSequenceValue( $seqName ) {
1137                 return NULL;
1138         }
1139
1140         /**
1141          * USE INDEX clause
1142          * PostgreSQL doesn't have them and returns ""
1143          */
1144         function useIndexClause( $index ) {
1145                 return "FORCE INDEX ($index)";
1146         }
1147
1148         /**
1149          * REPLACE query wrapper
1150          * PostgreSQL simulates this with a DELETE followed by INSERT
1151          * $row is the row to insert, an associative array
1152          * $uniqueIndexes is an array of indexes. Each element may be either a
1153          * field name or an array of field names
1154          *
1155          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1156          * However if you do this, you run the risk of encountering errors which wouldn't have
1157          * occurred in MySQL
1158          *
1159          * @todo migrate comment to phodocumentor format
1160          */
1161         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1162                 $table = $this->tableName( $table );
1163
1164                 # Single row case
1165                 if ( !is_array( reset( $rows ) ) ) {
1166                         $rows = array( $rows );
1167                 }
1168
1169                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1170                 $first = true;
1171                 foreach ( $rows as $row ) {
1172                         if ( $first ) {
1173                                 $first = false;
1174                         } else {
1175                                 $sql .= ',';
1176                         }
1177                         $sql .= '(' . $this->makeList( $row ) . ')';
1178                 }
1179                 return $this->query( $sql, $fname );
1180         }
1181
1182         /**
1183          * DELETE where the condition is a join
1184          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1185          *
1186          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1187          * join condition matches, set $conds='*'
1188          *
1189          * DO NOT put the join condition in $conds
1190          *
1191          * @param string $delTable The table to delete from.
1192          * @param string $joinTable The other table.
1193          * @param string $delVar The variable to join on, in the first table.
1194          * @param string $joinVar The variable to join on, in the second table.
1195          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1196          */
1197         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1198                 if ( !$conds ) {
1199                         wfDebugDieBacktrace( 'Database::deleteJoin() called with empty $conds' );
1200                 }
1201
1202                 $delTable = $this->tableName( $delTable );
1203                 $joinTable = $this->tableName( $joinTable );
1204                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1205                 if ( $conds != '*' ) {
1206                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1207                 }
1208
1209                 return $this->query( $sql, $fname );
1210         }
1211
1212         /**
1213          * Returns the size of a text field, or -1 for "unlimited"
1214          */
1215         function textFieldSize( $table, $field ) {
1216                 $table = $this->tableName( $table );
1217                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1218                 $res = $this->query( $sql, 'Database::textFieldSize' );
1219                 $row = $this->fetchObject( $res );
1220                 $this->freeResult( $res );
1221
1222                 if ( preg_match( "/\((.*)\)/", $row->Type, $m ) ) {
1223                         $size = $m[1];
1224                 } else {
1225                         $size = -1;
1226                 }
1227                 return $size;
1228         }
1229
1230         /**
1231          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1232          */
1233         function lowPriorityOption() {
1234                 return 'LOW_PRIORITY';
1235         }
1236
1237         /**
1238          * DELETE query wrapper
1239          *
1240          * Use $conds == "*" to delete all rows
1241          */
1242         function delete( $table, $conds, $fname = 'Database::delete' ) {
1243                 if ( !$conds ) {
1244                         wfDebugDieBacktrace( 'Database::delete() called with no conditions' );
1245                 }
1246                 $table = $this->tableName( $table );
1247                 $sql = "DELETE FROM $table";
1248                 if ( $conds != '*' ) {
1249                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1250                 }
1251                 return $this->query( $sql, $fname );
1252         }
1253
1254         /**
1255          * INSERT SELECT wrapper
1256          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1257          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1258          * $conds may be "*" to copy the whole table
1259          * srcTable may be an array of tables.
1260          */
1261         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect' ) {
1262                 $destTable = $this->tableName( $destTable );
1263                 if( is_array( $srcTable ) ) {
1264                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1265                 } else {
1266                         $srcTable = $this->tableName( $srcTable );
1267                 }
1268                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1269                         ' SELECT ' . implode( ',', $varMap ) .
1270                         " FROM $srcTable";
1271                 if ( $conds != '*' ) {
1272                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1273                 }
1274                 return $this->query( $sql, $fname );
1275         }
1276
1277         /**
1278          * Construct a LIMIT query with optional offset
1279          * This is used for query pages
1280          */
1281         function limitResult($sql, $limit, $offset) {
1282                 return "$sql LIMIT ".((is_numeric($offset) && $offset != 0)?"{$offset},":"")."{$limit} ";
1283         }
1284         function limitResultForUpdate($sql, $num) {
1285                 return $this->limitResult($sql, $num, 0);
1286         }
1287
1288         /**
1289          * Returns an SQL expression for a simple conditional.
1290          * Uses IF on MySQL.
1291          *
1292          * @param string $cond SQL expression which will result in a boolean value
1293          * @param string $trueVal SQL expression to return if true
1294          * @param string $falseVal SQL expression to return if false
1295          * @return string SQL fragment
1296          */
1297         function conditional( $cond, $trueVal, $falseVal ) {
1298                 return " IF($cond, $trueVal, $falseVal) ";
1299         }
1300
1301         /**
1302          * Determines if the last failure was due to a deadlock
1303          */
1304         function wasDeadlock() {
1305                 return $this->lastErrno() == 1213;
1306         }
1307
1308         /**
1309          * Perform a deadlock-prone transaction.
1310          *
1311          * This function invokes a callback function to perform a set of write
1312          * queries. If a deadlock occurs during the processing, the transaction
1313          * will be rolled back and the callback function will be called again.
1314          *
1315          * Usage:
1316          *   $dbw->deadlockLoop( callback, ... );
1317          *
1318          * Extra arguments are passed through to the specified callback function.
1319          *
1320          * Returns whatever the callback function returned on its successful,
1321          * iteration, or false on error, for example if the retry limit was
1322          * reached.
1323          */
1324         function deadlockLoop() {
1325                 $myFname = 'Database::deadlockLoop';
1326
1327                 $this->begin();
1328                 $args = func_get_args();
1329                 $function = array_shift( $args );
1330                 $oldIgnore = $this->ignoreErrors( true );
1331                 $tries = DEADLOCK_TRIES;
1332                 if ( is_array( $function ) ) {
1333                         $fname = $function[0];
1334                 } else {
1335                         $fname = $function;
1336                 }
1337                 do {
1338                         $retVal = call_user_func_array( $function, $args );
1339                         $error = $this->lastError();
1340                         $errno = $this->lastErrno();
1341                         $sql = $this->lastQuery();
1342
1343                         if ( $errno ) {
1344                                 if ( $this->wasDeadlock() ) {
1345                                         # Retry
1346                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1347                                 } else {
1348                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1349                                 }
1350                         }
1351                 } while( $this->wasDeadlock() && --$tries > 0 );
1352                 $this->ignoreErrors( $oldIgnore );
1353                 if ( $tries <= 0 ) {
1354                         $this->query( 'ROLLBACK', $myFname );
1355                         $this->reportQueryError( $error, $errno, $sql, $fname );
1356                         return false;
1357                 } else {
1358                         $this->query( 'COMMIT', $myFname );
1359                         return $retVal;
1360                 }
1361         }
1362
1363         /**
1364          * Do a SELECT MASTER_POS_WAIT()
1365          *
1366          * @param string $file the binlog file
1367          * @param string $pos the binlog position
1368          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1369          */
1370         function masterPosWait( $file, $pos, $timeout ) {
1371                 $fname = 'Database::masterPosWait';
1372                 wfProfileIn( $fname );
1373
1374
1375                 # Commit any open transactions
1376                 $this->immediateCommit();
1377
1378                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1379                 $encFile = $this->strencode( $file );
1380                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1381                 $res = $this->doQuery( $sql );
1382                 if ( $res && $row = $this->fetchRow( $res ) ) {
1383                         $this->freeResult( $res );
1384                         wfProfileOut( $fname );
1385                         return $row[0];
1386                 } else {
1387                         wfProfileOut( $fname );
1388                         return false;
1389                 }
1390         }
1391
1392         /**
1393          * Get the position of the master from SHOW SLAVE STATUS
1394          */
1395         function getSlavePos() {
1396                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1397                 $row = $this->fetchObject( $res );
1398                 if ( $row ) {
1399                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1400                 } else {
1401                         return array( false, false );
1402                 }
1403         }
1404
1405         /**
1406          * Get the position of the master from SHOW MASTER STATUS
1407          */
1408         function getMasterPos() {
1409                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1410                 $row = $this->fetchObject( $res );
1411                 if ( $row ) {
1412                         return array( $row->File, $row->Position );
1413                 } else {
1414                         return array( false, false );
1415                 }
1416         }
1417
1418         /**
1419          * Begin a transaction, or if a transaction has already started, continue it
1420          */
1421         function begin( $fname = 'Database::begin' ) {
1422                 if ( !$this->mTrxLevel ) {
1423                         $this->immediateBegin( $fname );
1424                 } else {
1425                         $this->mTrxLevel++;
1426                 }
1427         }
1428
1429         /**
1430          * End a transaction, or decrement the nest level if transactions are nested
1431          */
1432         function commit( $fname = 'Database::commit' ) {
1433                 if ( $this->mTrxLevel ) {
1434                         $this->mTrxLevel--;
1435                 }
1436                 if ( !$this->mTrxLevel ) {
1437                         $this->immediateCommit( $fname );
1438                 }
1439         }
1440
1441         /**
1442          * Rollback a transaction
1443          */
1444         function rollback( $fname = 'Database::rollback' ) {
1445                 $this->query( 'ROLLBACK', $fname );
1446                 $this->mTrxLevel = 0;
1447         }
1448
1449         /**
1450          * Begin a transaction, committing any previously open transaction
1451          */
1452         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1453                 $this->query( 'BEGIN', $fname );
1454                 $this->mTrxLevel = 1;
1455         }
1456
1457         /**
1458          * Commit transaction, if one is open
1459          */
1460         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1461                 $this->query( 'COMMIT', $fname );
1462                 $this->mTrxLevel = 0;
1463         }
1464
1465         /**
1466          * Return MW-style timestamp used for MySQL schema
1467          */
1468         function timestamp( $ts=0 ) {
1469                 return wfTimestamp(TS_MW,$ts);
1470         }
1471
1472         /**
1473          * Local database timestamp format or null
1474          */
1475         function timestampOrNull( $ts = null ) {
1476                 if( is_null( $ts ) ) {
1477                         return null;
1478                 } else {
1479                         return $this->timestamp( $ts );
1480                 }
1481         }
1482
1483         /**
1484          * @todo document
1485          */
1486         function resultObject( &$result ) {
1487                 if( empty( $result ) ) {
1488                         return NULL;
1489                 } else {
1490                         return new ResultWrapper( $this, $result );
1491                 }
1492         }
1493
1494         /**
1495          * Return aggregated value alias
1496          */
1497         function aggregateValue ($valuedata,$valuename='value') {
1498                 return $valuename;
1499         }
1500
1501         /**
1502          * @return string wikitext of a link to the server software's web site
1503          */
1504         function getSoftwareLink() {
1505                 return "[http://www.mysql.com/ MySQL]";
1506         }
1507
1508         /**
1509          * @return string Version information from the database
1510          */
1511         function getServerVersion() {
1512                 return mysql_get_server_info();
1513         }
1514
1515         /**
1516          * Ping the server and try to reconnect if it there is no connection
1517          */
1518         function ping() {
1519                 if( function_exists( 'mysql_ping' ) ) {
1520                         return mysql_ping( $this->mConn );
1521                 } else {
1522                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1523                         return true;
1524                 }
1525         }
1526
1527         /**
1528          * Get slave lag.
1529          * At the moment, this will only work if the DB user has the PROCESS privilege
1530          */
1531         function getLag() {
1532                 $res = $this->query( 'SHOW PROCESSLIST' );
1533                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1534                 # dubious, but unfortunately there's no easy rigorous way
1535                 $slaveThreads = 0;
1536                 while ( $row = $this->fetchObject( $res ) ) {
1537                         if ( $row->User == 'system user' ) {
1538                                 if ( ++$slaveThreads == 2 ) {
1539                                         # This is it, return the time
1540                                         return $row->Time;
1541                                 }
1542                         }
1543                 }
1544                 return false;
1545         }
1546
1547         /**
1548          * Get status information from SHOW STATUS in an associative array
1549          */
1550         function getStatus() {
1551                 $res = $this->query( 'SHOW STATUS' );
1552                 $status = array();
1553                 while ( $row = $this->fetchObject( $res ) ) {
1554                         $status[$row->Variable_name] = $row->Value;
1555                 }
1556                 return $status;
1557         }
1558
1559         /**
1560          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1561          */
1562         function maxListLen() {
1563                 return 0;
1564         }
1565
1566         function encodeBlob($b) {
1567                 return $b;
1568         }
1569
1570         function notNullTimestamp() {
1571                 return "!= 0";
1572         }
1573         function isNullTimestamp() {
1574                 return "= '0'";
1575         }
1576 }
1577
1578 /**
1579  * Database abstraction object for mySQL
1580  * Inherit all methods and properties of Database::Database()
1581  *
1582  * @package MediaWiki
1583  * @see Database
1584  */
1585 class DatabaseMysql extends Database {
1586         # Inherit all
1587 }
1588
1589
1590 /**
1591  * Result wrapper for grabbing data queried by someone else
1592  *
1593  * @package MediaWiki
1594  */
1595 class ResultWrapper {
1596         var $db, $result;
1597
1598         /**
1599          * @todo document
1600          */
1601         function ResultWrapper( $database, $result ) {
1602                 $this->db =& $database;
1603                 $this->result =& $result;
1604         }
1605
1606         /**
1607          * @todo document
1608          */
1609         function numRows() {
1610                 return $this->db->numRows( $this->result );
1611         }
1612
1613         /**
1614          * @todo document
1615          */
1616         function fetchObject() {
1617                 return $this->db->fetchObject( $this->result );
1618         }
1619
1620         /**
1621          * @todo document
1622          */
1623         function &fetchRow() {
1624                 return $this->db->fetchRow( $this->result );
1625         }
1626
1627         /**
1628          * @todo document
1629          */
1630         function free() {
1631                 $this->db->freeResult( $this->result );
1632                 unset( $this->result );
1633                 unset( $this->db );
1634         }
1635
1636         function seek( $row ) {
1637                 $this->db->dataSeek( $this->result, $row );
1638         }
1639 }
1640
1641 #------------------------------------------------------------------------------
1642 # Global functions
1643 #------------------------------------------------------------------------------
1644
1645 /**
1646  * Standard fail function, called by default when a connection cannot be
1647  * established.
1648  * Displays the file cache if possible
1649  */
1650 function wfEmergencyAbort( &$conn, $error ) {
1651         global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgOutputEncoding;
1652         global $wgSitename, $wgServer;
1653
1654         # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
1655         # Hard coding strings instead.
1656
1657         $noconnect = 'Sorry! The wiki is experiencing some technical difficulties, and cannot contact the database server: $1. <br />
1658 $1';
1659         $mainpage = 'Main Page';
1660         $searchdisabled = <<<EOT
1661 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
1662 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
1663 EOT;
1664
1665         $googlesearch = "
1666 <!-- SiteSearch Google -->
1667 <FORM method=GET action=\"http://www.google.com/search\">
1668 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
1669 <A HREF=\"http://www.google.com/\">
1670 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
1671 border=\"0\" ALT=\"Google\"></A>
1672 </td>
1673 <td>
1674 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
1675 <INPUT type=submit name=btnG VALUE=\"Google Search\">
1676 <font size=-1>
1677 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
1678 <input type='hidden' name='ie' value='$2'>
1679 <input type='hidden' name='oe' value='$2'>
1680 </font>
1681 </td></tr></TABLE>
1682 </FORM>
1683 <!-- SiteSearch Google -->";
1684         $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
1685
1686
1687         if( !headers_sent() ) {
1688                 header( 'HTTP/1.0 500 Internal Server Error' );
1689                 header( 'Content-type: text/html; charset='.$wgOutputEncoding );
1690                 /* Don't cache error pages!  They cause no end of trouble... */
1691                 header( 'Cache-control: none' );
1692                 header( 'Pragma: nocache' );
1693         }
1694         $msg = wfGetSiteNotice();
1695         if($msg == '') {
1696                 $msg = str_replace( '$1', $error, $noconnect );
1697         }
1698         $text = $msg;
1699
1700         if($wgUseFileCache) {
1701                 if($wgTitle) {
1702                         $t =& $wgTitle;
1703                 } else {
1704                         if($title) {
1705                                 $t = Title::newFromURL( $title );
1706                         } elseif (@/**/$_REQUEST['search']) {
1707                                 $search = $_REQUEST['search'];
1708                                 echo $searchdisabled;
1709                                 echo str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
1710                                   $wgInputEncoding ), $googlesearch );
1711                                 wfErrorExit();
1712                         } else {
1713                                 $t = Title::newFromText( $mainpage );
1714                         }
1715                 }
1716
1717                 $cache = new CacheManager( $t );
1718                 if( $cache->isFileCached() ) {
1719                         $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
1720                                 $cachederror . "</b></p>\n";
1721
1722                         $tag = '<div id="article">';
1723                         $text = str_replace(
1724                                 $tag,
1725                                 $tag . $msg,
1726                                 $cache->fetchPageText() );
1727                 }
1728         }
1729
1730         echo $text;
1731         wfErrorExit();
1732 }
1733
1734 ?>