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