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