includes/Database.php

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