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