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