includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  * @package MediaWiki
   6  */
   7
   8 /**
   9  * Depends on the CacheManager
  10  */
  11 require_once( 'CacheManager.php' );
  12
  13 /** See Database::makeList() */
  14 define( 'LIST_COMMA', 0 );
  15 define( 'LIST_AND', 1 );
  16 define( 'LIST_SET', 2 );
  17 define( 'LIST_NAMES', 3);
  18
  19 /** Number of times to re-try an operation in case of deadlock */
  20 define( 'DEADLOCK_TRIES', 4 );
  21 /** Minimum time to wait before retry, in microseconds */
  22 define( 'DEADLOCK_DELAY_MIN', 500000 );
  23 /** Maximum time to wait before retry */
  24 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  25
  26 /**
  27  * Database abstraction object
  28  * @package MediaWiki
  29  */
  30 class Database {
  31
  32 #------------------------------------------------------------------------------
  33 # Variables
  34 #------------------------------------------------------------------------------
  35         /**#@+
  36          * @access private
  37          */
  38         var $mLastQuery = '';
  39
  40         var $mServer, $mUser, $mPassword, $mConn, $mDBname;
  41         var $mOut, $mOpened = false;
  42
  43         var $mFailFunction;
  44         var $mTablePrefix;
  45         var $mFlags;
  46         var $mTrxLevel = 0;
  47         var $mErrorCount = 0;
  48         /**#@-*/
  49
  50 #------------------------------------------------------------------------------
  51 # Accessors
  52 #------------------------------------------------------------------------------
  53         # These optionally set a variable and return the previous state
  54
  55         /**
  56          * Fail function, takes a Database as a parameter
  57          * Set to false for default, 1 for ignore errors
  58          */
  59         function failFunction( $function = NULL ) {
  60                 return wfSetVar( $this->mFailFunction, $function );
  61         }
  62
  63         /**
  64          * Output page, used for reporting errors
  65          * FALSE means discard output
  66          */
  67         function &setOutputPage( &$out ) {
  68                 $this->mOut =& $out;
  69         }
  70
  71         /**
  72          * Boolean, controls output of large amounts of debug information
  73          */
  74         function debug( $debug = NULL ) {
  75                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  76         }
  77
  78         /**
  79          * Turns buffering of SQL result sets on (true) or off (false).
  80          * Default is "on" and it should not be changed without good reasons.
  81          */
  82         function bufferResults( $buffer = NULL ) {
  83                 if ( is_null( $buffer ) ) {
  84                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  85                 } else {
  86                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  87                 }
  88         }
  89
  90         /**
  91          * Turns on (false) or off (true) the automatic generation and sending
  92          * of a "we're sorry, but there has been a database error" page on
  93          * database errors. Default is on (false). When turned off, the
  94          * code should use wfLastErrno() and wfLastError() to handle the
  95          * situation as appropriate.
  96          */
  97         function ignoreErrors( $ignoreErrors = NULL ) {
  98                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  99         }
 100
 101         /**
 102          * The current depth of nested transactions
 103          * @param integer $level
 104          */
 105         function trxLevel( $level = NULL ) {
 106                 return wfSetVar( $this->mTrxLevel, $level );
 107         }
 108
 109         /**
 110          * Number of errors logged, only useful when errors are ignored
 111          */
 112         function errorCount( $count = NULL ) {
 113                 return wfSetVar( $this->mErrorCount, $count );
 114         }
 115
 116         /**#@+
 117          * Get function
 118          */
 119         function lastQuery() { return $this->mLastQuery; }
 120         function isOpen() { return $this->mOpened; }
 121         /**#@-*/
 122
 123 #------------------------------------------------------------------------------
 124 # Other functions
 125 #------------------------------------------------------------------------------
 126
 127         /**#@+
 128          * @param string $server database server host
 129          * @param string $user database user name
 130          * @param string $password database user password
 131          * @param string $dbname database name
 132          */
 133
 134         /**
 135          * @param failFunction
 136          * @param $flags
 137          * @param string $tablePrefix Database table prefixes. By default use the prefix gave in LocalSettings.php
 138          */
 139         function Database( $server = false, $user = false, $password = false, $dbName = false,
 140                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 141
 142                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 143                 # Can't get a reference if it hasn't been set yet
 144                 if ( !isset( $wgOut ) ) {
 145                         $wgOut = NULL;
 146                 }
 147                 $this->mOut =& $wgOut;
 148
 149                 $this->mFailFunction = $failFunction;
 150                 $this->mFlags = $flags;
 151
 152                 if ( $this->mFlags & DBO_DEFAULT ) {
 153                         if ( $wgCommandLineMode ) {
 154                                 $this->mFlags &= ~DBO_TRX;
 155                         } else {
 156                                 $this->mFlags |= DBO_TRX;
 157                         }
 158                 }
 159
 160                 /*
 161                 // Faster read-only access
 162                 if ( wfReadOnly() ) {
 163                         $this->mFlags |= DBO_PERSISTENT;
 164                         $this->mFlags &= ~DBO_TRX;
 165                 }*/
 166
 167                 /** Get the default table prefix*/
 168                 if ( $tablePrefix == 'get from global' ) {
 169                         $this->mTablePrefix = $wgDBprefix;
 170                 } else {
 171                         $this->mTablePrefix = $tablePrefix;
 172                 }
 173
 174                 if ( $server ) {
 175                         $this->open( $server, $user, $password, $dbName );
 176                 }
 177         }
 178
 179         /**
 180          * @static
 181          * @param failFunction
 182          * @param $flags
 183          */
 184         function newFromParams( $server, $user, $password, $dbName,
 185                 $failFunction = false, $flags = 0 )
 186         {
 187                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 188         }
 189
 190         /**
 191          * Usually aborts on failure
 192          * If the failFunction is set to a non-zero integer, returns success
 193          */
 194         function open( $server, $user, $password, $dbName ) {
 195                 # Test for missing mysql.so
 196                 # First try to load it
 197                 if (!@extension_loaded('mysql')) {
 198                         @dl('mysql.so');
 199                 }
 200
 201                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 202                 if ( !function_exists( 'mysql_connect' ) ) {
 203                         die( "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 204                 }
 205
 206                 $this->close();
 207                 $this->mServer = $server;
 208                 $this->mUser = $user;
 209                 $this->mPassword = $password;
 210                 $this->mDBname = $dbName;
 211
 212                 $success = false;
 213
 214                 if ( $this->mFlags & DBO_PERSISTENT ) {
 215                         @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 216                 } else {
 217                         @/**/$this->mConn = mysql_connect( $server, $user, $password );
 218                 }
 219
 220                 if ( $dbName != '' ) {
 221                         if ( $this->mConn !== false ) {
 222                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 223                                 if ( !$success ) {
 224                                         wfDebug( "Error selecting database \"$dbName\": " . $this->lastError() . "\n" );
 225                                 }
 226                         } else {
 227                                 wfDebug( "DB connection error\n" );
 228                                 wfDebug( "Server: $server, User: $user, Password: " .
 229                                         substr( $password, 0, 3 ) . "...\n" );
 230                                 $success = false;
 231                         }
 232                 } else {
 233                         # Delay USE query
 234                         $success = !!$this->mConn;
 235                 }
 236
 237                 if ( !$success ) {
 238                         $this->reportConnectionError();
 239                         $this->close();
 240                 }
 241                 $this->mOpened = $success;
 242                 return $success;
 243         }
 244         /**#@-*/
 245
 246         /**
 247          * Closes a database connection.
 248          * if it is open : commits any open transactions
 249          *
 250          * @return bool operation success. true if already closed.
 251          */
 252         function close()
 253         {
 254                 $this->mOpened = false;
 255                 if ( $this->mConn ) {
 256                         if ( $this->trxLevel() ) {
 257                                 $this->immediateCommit();
 258                         }
 259                         return mysql_close( $this->mConn );
 260                 } else {
 261                         return true;
 262                 }
 263         }
 264
 265         /**
 266          * @access private
 267          * @param string $msg error message ?
 268          * @todo parameter $msg is not used
 269          */
 270         function reportConnectionError( $msg = '') {
 271                 if ( $this->mFailFunction ) {
 272                         if ( !is_int( $this->mFailFunction ) ) {
 273                                 $ff = $this->mFailFunction;
 274                                 $ff( $this, mysql_error() );
 275                         }
 276                 } else {
 277                         wfEmergencyAbort( $this, mysql_error() );
 278                 }
 279         }
 280
 281         /**
 282          * Usually aborts on failure
 283          * If errors are explicitly ignored, returns success
 284          */
 285         function query( $sql, $fname = '', $tempIgnore = false ) {
 286                 global $wgProfiling, $wgCommandLineMode;
 287
 288                 if ( $wgProfiling ) {
 289                         # generalizeSQL will probably cut down the query to reasonable
 290                         # logging size most of the time. The substr is really just a sanity check.
 291                         $profName = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 292                         wfProfileIn( 'Database::query' );
 293                         wfProfileIn( $profName );
 294                 }
 295
 296                 $this->mLastQuery = $sql;
 297
 298                 # Add a comment for easy SHOW PROCESSLIST interpretation
 299                 if ( $fname ) {
 300                         $commentedSql = "/* $fname */ $sql";
 301                 } else {
 302                         $commentedSql = $sql;
 303                 }
 304
 305                 # If DBO_TRX is set, start a transaction
 306                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() && $sql != 'BEGIN' ) {
 307                         $this->begin();
 308                 }
 309
 310                 if ( $this->debug() ) {
 311                         $sqlx = substr( $sql, 0, 500 );
 312                         $sqlx = strtr($sqlx,"\t\n",'  ');
 313                         wfDebug( "SQL: $sqlx\n" );
 314                 }
 315
 316                 # Do the query and handle errors
 317                 $ret = $this->doQuery( $commentedSql );
 318
 319                 # Try reconnecting if the connection was lost
 320                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 321                         # Transaction is gone, like it or not
 322                         $this->mTrxLevel = 0;
 323                         wfDebug( "Connection lost, reconnecting...\n" );
 324                         if ( $this->ping() ) {
 325                                 wfDebug( "Reconnected\n" );
 326                                 $ret = $this->doQuery( $commentedSql );
 327                         } else {
 328                                 wfDebug( "Failed\n" );
 329                         }
 330                 }
 331
 332                 if ( false === $ret ) {
 333                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 334                 }
 335
 336                 if ( $wgProfiling ) {
 337                         wfProfileOut( $profName );
 338                         wfProfileOut( 'Database::query' );
 339                 }
 340                 return $ret;
 341         }
 342
 343         /**
 344          * The DBMS-dependent part of query()
 345          * @param string $sql SQL query.
 346          */
 347         function doQuery( $sql ) {
 348                 if( $this->bufferResults() ) {
 349                         $ret = mysql_query( $sql, $this->mConn );
 350                 } else {
 351                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 352                 }
 353                 return $ret;
 354         }
 355
 356         /**
 357          * @param $error
 358          * @param $errno
 359          * @param $sql
 360          * @param string $fname
 361          * @param bool $tempIgnore
 362          */
 363         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 364                 global $wgCommandLineMode, $wgFullyInitialised;
 365                 # Ignore errors during error handling to avoid infinite recursion
 366                 $ignore = $this->ignoreErrors( true );
 367                 $this->mErrorCount ++;
 368
 369                 if( $ignore || $tempIgnore ) {
 370                         wfDebug("SQL ERROR (ignored): " . $error . "\n");
 371                 } else {
 372                         $sql1line = str_replace( "\n", "\\n", $sql );
 373                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 374                         wfDebug("SQL ERROR: " . $error . "\n");
 375                         if ( $wgCommandLineMode || !$this->mOut || empty( $wgFullyInitialised ) ) {
 376                                 $message = "A database error has occurred\n" .
 377                                   "Query: $sql\n" .
 378                                   "Function: $fname\n" .
 379                                   "Error: $errno $error\n";
 380                                 if ( !$wgCommandLineMode ) {
 381                                         $message = nl2br( $message );
 382                                 }
 383                                 wfDebugDieBacktrace( $message );
 384                         } else {
 385                                 // this calls wfAbruptExit()
 386                                 $this->mOut->databaseError( $fname, $sql, $error, $errno );
 387                         }
 388                 }
 389                 $this->ignoreErrors( $ignore );
 390         }
 391
 392
 393         /**
 394          * Intended to be compatible with the PEAR::DB wrapper functions.
 395          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 396          *
 397          * ? = scalar value, quoted as necessary
 398          * ! = raw SQL bit (a function for instance)
 399          * & = filename; reads the file and inserts as a blob
 400          *     (we don't use this though...)
 401          */
 402         function prepare( $sql, $func = 'Database::prepare' ) {
 403                 /* MySQL doesn't support prepared statements (yet), so just
 404                    pack up the query for reference. We'll manually replace
 405                    the bits later. */
 406                 return array( 'query' => $sql, 'func' => $func );
 407         }
 408
 409         function freePrepared( $prepared ) {
 410                 /* No-op for MySQL */
 411         }
 412
 413         /**
 414          * Execute a prepared query with the various arguments
 415          * @param string $prepared the prepared sql
 416          * @param mixed $args Either an array here, or put scalars as varargs
 417          */
 418         function execute( $prepared, $args = null ) {
 419                 if( !is_array( $args ) ) {
 420                         # Pull the var args
 421                         $args = func_get_args();
 422                         array_shift( $args );
 423                 }
 424                 $sql = $this->fillPrepared( $prepared['query'], $args );
 425                 return $this->query( $sql, $prepared['func'] );
 426         }
 427
 428         /**
 429          * Prepare & execute an SQL statement, quoting and inserting arguments
 430          * in the appropriate places.
 431          * @param string $query
 432          * @param string $args (default null)
 433          */
 434         function safeQuery( $query, $args = null ) {
 435                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 436                 if( !is_array( $args ) ) {
 437                         # Pull the var args
 438                         $args = func_get_args();
 439                         array_shift( $args );
 440                 }
 441                 $retval = $this->execute( $prepared, $args );
 442                 $this->freePrepared( $prepared );
 443                 return $retval;
 444         }
 445
 446         /**
 447          * For faking prepared SQL statements on DBs that don't support
 448          * it directly.
 449          * @param string $preparedSql - a 'preparable' SQL statement
 450          * @param array $args - array of arguments to fill it with
 451          * @return string executable SQL
 452          */
 453         function fillPrepared( $preparedQuery, $args ) {
 454                 $n = 0;
 455                 reset( $args );
 456                 $this->preparedArgs =& $args;
 457                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 458                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 459         }
 460
 461         /**
 462          * preg_callback func for fillPrepared()
 463          * The arguments should be in $this->preparedArgs and must not be touched
 464          * while we're doing this.
 465          *
 466          * @param array $matches
 467          * @return string
 468          * @access private
 469          */
 470         function fillPreparedArg( $matches ) {
 471                 switch( $matches[1] ) {
 472                         case '\\?': return '?';
 473                         case '\\!': return '!';
 474                         case '\\&': return '&';
 475                 }
 476                 list( $n, $arg ) = each( $this->preparedArgs );
 477                 switch( $matches[1] ) {
 478                         case '?': return $this->addQuotes( $arg );
 479                         case '!': return $arg;
 480                         case '&':
 481                                 # return $this->addQuotes( file_get_contents( $arg ) );
 482                                 wfDebugDieBacktrace( '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 483                         default:
 484                                 wfDebugDieBacktrace( 'Received invalid match. This should never happen!' );
 485                 }
 486         }
 487
 488         /**#@+
 489          * @param mixed $res A SQL result
 490          */
 491         /**
 492          * Free a result object
 493          */
 494         function freeResult( $res ) {
 495                 if ( !@/**/mysql_free_result( $res ) ) {
 496                         wfDebugDieBacktrace( "Unable to free MySQL result\n" );
 497                 }
 498         }
 499
 500         /**
 501          * Fetch the next row from the given result object, in object form
 502          */
 503         function fetchObject( $res ) {
 504                 @/**/$row = mysql_fetch_object( $res );
 505                 if( mysql_errno() ) {
 506                         wfDebugDieBacktrace( 'Error in fetchObject(): ' . htmlspecialchars( mysql_error() ) );
 507                 }
 508                 return $row;
 509         }
 510
 511         /**
 512          * Fetch the next row from the given result object
 513          * Returns an array
 514          */
 515         function fetchRow( $res ) {
 516                 @/**/$row = mysql_fetch_array( $res );
 517                 if (mysql_errno() ) {
 518                         wfDebugDieBacktrace( 'Error in fetchRow(): ' . htmlspecialchars( mysql_error() ) );
 519                 }
 520                 return $row;
 521         }
 522
 523         /**
 524          * Get the number of rows in a result object
 525          */
 526         function numRows( $res ) {
 527                 @/**/$n = mysql_num_rows( $res );
 528                 if( mysql_errno() ) {
 529                         wfDebugDieBacktrace( 'Error in numRows(): ' . htmlspecialchars( mysql_error() ) );
 530                 }
 531                 return $n;
 532         }
 533
 534         /**
 535          * Get the number of fields in a result object
 536          * See documentation for mysql_num_fields()
 537          */
 538         function numFields( $res ) { return mysql_num_fields( $res ); }
 539
 540         /**
 541          * Get a field name in a result object
 542          * See documentation for mysql_field_name()
 543          */
 544         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 545
 546         /**
 547          * Get the inserted value of an auto-increment row
 548          *
 549          * The value inserted should be fetched from nextSequenceValue()
 550          *
 551          * Example:
 552          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 553          * $dbw->insert('page',array('page_id' => $id));
 554          * $id = $dbw->insertId();
 555          */
 556         function insertId() { return mysql_insert_id( $this->mConn ); }
 557
 558         /**
 559          * Change the position of the cursor in a result object
 560          * See mysql_data_seek()
 561          */
 562         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 563
 564         /**
 565          * Get the last error number
 566          * See mysql_errno()
 567          */
 568         function lastErrno() {
 569                 if ( $this->mConn ) {
 570                         return mysql_errno( $this->mConn );
 571                 } else {
 572                         return mysql_errno();
 573                 }
 574         }
 575
 576         /**
 577          * Get a description of the last error
 578          * See mysql_error() for more details
 579          */
 580         function lastError() {
 581                 if ( $this->mConn ) {
 582                         $error = mysql_error( $this->mConn );
 583                 } else {
 584                         $error = mysql_error();
 585                 }
 586                 if( $error ) {
 587                         $error .= ' (' . $this->mServer . ')';
 588                 }
 589                 return $error;
 590         }
 591         /**
 592          * Get the number of rows affected by the last write query
 593          * See mysql_affected_rows() for more details
 594          */
 595         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 596         /**#@-*/ // end of template : @param $result
 597
 598         /**
 599          * Simple UPDATE wrapper
 600          * Usually aborts on failure
 601          * If errors are explicitly ignored, returns success
 602          *
 603          * This function exists for historical reasons, Database::update() has a more standard
 604          * calling convention and feature set
 605          */
 606         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 607         {
 608                 $table = $this->tableName( $table );
 609                 $sql = "UPDATE $table SET $var = '" .
 610                   $this->strencode( $value ) . "' WHERE ($cond)";
 611                 return !!$this->query( $sql, DB_MASTER, $fname );
 612         }
 613
 614         /**
 615          * Simple SELECT wrapper, returns a single field, input must be encoded
 616          * Usually aborts on failure
 617          * If errors are explicitly ignored, returns FALSE on failure
 618          */
 619         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 620                 if ( !is_array( $options ) ) {
 621                         $options = array( $options );
 622                 }
 623                 $options['LIMIT'] = 1;
 624
 625                 $res = $this->select( $table, $var, $cond, $fname, $options );
 626                 if ( $res === false || !$this->numRows( $res ) ) {
 627                         return false;
 628                 }
 629                 $row = $this->fetchRow( $res );
 630                 if ( $row !== false ) {
 631                         $this->freeResult( $res );
 632                         return $row[0];
 633                 } else {
 634                         return false;
 635                 }
 636         }
 637
 638         /**
 639          * Returns an optional USE INDEX clause to go after the table, and a
 640          * string to go at the end of the query
 641          *
 642          * @access private
 643          *
 644          * @param array $options an associative array of options to be turned into
 645          *              an SQL query, valid keys are listed in the function.
 646          * @return array
 647          */
 648         function makeSelectOptions( $options ) {
 649                 $tailOpts = '';
 650
 651                 if ( isset( $options['ORDER BY'] ) ) {
 652                         $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 653                 }
 654                 if ( isset( $options['LIMIT'] ) ) {
 655                         $tailOpts .= " LIMIT {$options['LIMIT']}";
 656                 }
 657
 658                 if ( is_numeric( array_search( 'FOR UPDATE', $options ) ) ) {
 659                         $tailOpts .= ' FOR UPDATE';
 660                 }
 661
 662                 if ( is_numeric( array_search( 'LOCK IN SHARE MODE', $options ) ) ) {
 663                         $tailOpts .= ' LOCK IN SHARE MODE';
 664                 }
 665
 666                 if ( isset( $options['USE INDEX'] ) ) {
 667                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 668                 } else {
 669                         $useIndex = '';
 670                 }
 671                 return array( $useIndex, $tailOpts );
 672         }
 673
 674         /**
 675          * SELECT wrapper
 676          */
 677         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
 678         {
 679                 if( is_array( $vars ) ) {
 680                         $vars = implode( ',', $vars );
 681                 }
 682                 if( is_array( $table ) ) {
 683                         $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 684                 } elseif ($table!='') {
 685                         $from = ' FROM ' .$this->tableName( $table );
 686                 } else {
 687                         $from = '';
 688                 }
 689
 690                 list( $useIndex, $tailOpts ) = $this->makeSelectOptions( (array)$options );
 691
 692                 if( !empty( $conds ) ) {
 693                         if ( is_array( $conds ) ) {
 694                                 $conds = $this->makeList( $conds, LIST_AND );
 695                         }
 696                         $sql = "SELECT $vars $from $useIndex WHERE $conds $tailOpts";
 697                 } else {
 698                         $sql = "SELECT $vars $from $useIndex $tailOpts";
 699                 }
 700                 return $this->query( $sql, $fname );
 701         }
 702
 703         /**
 704          * Single row SELECT wrapper
 705          * Aborts or returns FALSE on error
 706          *
 707          * $vars: the selected variables
 708          * $conds: a condition map, terms are ANDed together.
 709          *   Items with numeric keys are taken to be literal conditions
 710          * Takes an array of selected variables, and a condition map, which is ANDed
 711          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 712          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 713          * $obj- >page_id is the ID of the Astronomy article
 714          *
 715          * @todo migrate documentation to phpdocumentor format
 716          */
 717         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
 718                 $options['LIMIT'] = 1;
 719                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 720                 if ( $res === false || !$this->numRows( $res ) ) {
 721                         return false;
 722                 }
 723                 $obj = $this->fetchObject( $res );
 724                 $this->freeResult( $res );
 725                 return $obj;
 726
 727         }
 728
 729         /**
 730          * Removes most variables from an SQL query and replaces them with X or N for numbers.
 731          * It's only slightly flawed. Don't use for anything important.
 732          *
 733          * @param string $sql A SQL Query
 734          * @static
 735          */
 736         function generalizeSQL( $sql ) {
 737                 # This does the same as the regexp below would do, but in such a way
 738                 # as to avoid crashing php on some large strings.
 739                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
 740
 741                 $sql = str_replace ( "\\\\", '', $sql);
 742                 $sql = str_replace ( "\\'", '', $sql);
 743                 $sql = str_replace ( "\\\"", '', $sql);
 744                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
 745                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
 746
 747                 # All newlines, tabs, etc replaced by single space
 748                 $sql = preg_replace ( "/\s+/", ' ', $sql);
 749
 750                 # All numbers => N
 751                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
 752
 753                 return $sql;
 754         }
 755
 756         /**
 757          * Determines whether a field exists in a table
 758          * Usually aborts on failure
 759          * If errors are explicitly ignored, returns NULL on failure
 760          */
 761         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
 762                 $table = $this->tableName( $table );
 763                 $res = $this->query( 'DESCRIBE '.$table, DB_SLAVE, $fname );
 764                 if ( !$res ) {
 765                         return NULL;
 766                 }
 767
 768                 $found = false;
 769
 770                 while ( $row = $this->fetchObject( $res ) ) {
 771                         if ( $row->Field == $field ) {
 772                                 $found = true;
 773                                 break;
 774                         }
 775                 }
 776                 return $found;
 777         }
 778
 779         /**
 780          * Determines whether an index exists
 781          * Usually aborts on failure
 782          * If errors are explicitly ignored, returns NULL on failure
 783          */
 784         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
 785                 $info = $this->indexInfo( $table, $index, $fname );
 786                 if ( is_null( $info ) ) {
 787                         return NULL;
 788                 } else {
 789                         return $info !== false;
 790                 }
 791         }
 792
 793
 794         /**
 795          * Get information about an index into an object
 796          * Returns false if the index does not exist
 797          */
 798         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
 799                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 800                 # SHOW INDEX should work for 3.x and up:
 801                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 802                 $table = $this->tableName( $table );
 803                 $sql = 'SHOW INDEX FROM '.$table;
 804                 $res = $this->query( $sql, $fname );
 805                 if ( !$res ) {
 806                         return NULL;
 807                 }
 808
 809                 while ( $row = $this->fetchObject( $res ) ) {
 810                         if ( $row->Key_name == $index ) {
 811                                 return $row;
 812                         }
 813                 }
 814                 return false;
 815         }
 816
 817         /**
 818          * Query whether a given table exists
 819          */
 820         function tableExists( $table ) {
 821                 $table = $this->tableName( $table );
 822                 $old = $this->ignoreErrors( true );
 823                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
 824                 $this->ignoreErrors( $old );
 825                 if( $res ) {
 826                         $this->freeResult( $res );
 827                         return true;
 828                 } else {
 829                         return false;
 830                 }
 831         }
 832
 833         /**
 834          * mysql_fetch_field() wrapper
 835          * Returns false if the field doesn't exist
 836          *
 837          * @param $table
 838          * @param $field
 839          */
 840         function fieldInfo( $table, $field ) {
 841                 $table = $this->tableName( $table );
 842                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
 843                 $n = mysql_num_fields( $res );
 844                 for( $i = 0; $i < $n; $i++ ) {
 845                         $meta = mysql_fetch_field( $res, $i );
 846                         if( $field == $meta->name ) {
 847                                 return $meta;
 848                         }
 849                 }
 850                 return false;
 851         }
 852
 853         /**
 854          * mysql_field_type() wrapper
 855          */
 856         function fieldType( $res, $index ) {
 857                 return mysql_field_type( $res, $index );
 858         }
 859
 860         /**
 861          * Determines if a given index is unique
 862          */
 863         function indexUnique( $table, $index ) {
 864                 $indexInfo = $this->indexInfo( $table, $index );
 865                 if ( !$indexInfo ) {
 866                         return NULL;
 867                 }
 868                 return !$indexInfo->Non_unique;
 869         }
 870
 871         /**
 872          * INSERT wrapper, inserts an array into a table
 873          *
 874          * $a may be a single associative array, or an array of these with numeric keys, for
 875          * multi-row insert.
 876          *
 877          * Usually aborts on failure
 878          * If errors are explicitly ignored, returns success
 879          */
 880         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
 881                 # No rows to insert, easy just return now
 882                 if ( !count( $a ) ) {
 883                         return true;
 884                 }
 885
 886                 $table = $this->tableName( $table );
 887                 if ( !is_array( $options ) ) {
 888                         $options = array( $options );
 889                 }
 890                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 891                         $multi = true;
 892                         $keys = array_keys( $a[0] );
 893                 } else {
 894                         $multi = false;
 895                         $keys = array_keys( $a );
 896                 }
 897
 898                 $sql = 'INSERT ' . implode( ' ', $options ) .
 899                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 900
 901                 if ( $multi ) {
 902                         $first = true;
 903                         foreach ( $a as $row ) {
 904                                 if ( $first ) {
 905                                         $first = false;
 906                                 } else {
 907                                         $sql .= ',';
 908                                 }
 909                                 $sql .= '(' . $this->makeList( $row ) . ')';
 910                         }
 911                 } else {
 912                         $sql .= '(' . $this->makeList( $a ) . ')';
 913                 }
 914                 return !!$this->query( $sql, $fname );
 915         }
 916
 917         /**
 918          * UPDATE wrapper, takes a condition array and a SET array
 919          */
 920         function update( $table, $values, $conds, $fname = 'Database::update' ) {
 921                 $table = $this->tableName( $table );
 922                 $sql = "UPDATE $table SET " . $this->makeList( $values, LIST_SET );
 923                 $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
 924                 $this->query( $sql, $fname );
 925         }
 926
 927         /**
 928          * Makes a wfStrencoded list from an array
 929          * $mode: LIST_COMMA         - comma separated, no field names
 930          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
 931          *        LIST_SET           - comma separated with field names, like a SET clause
 932          *        LIST_NAMES         - comma separated field names
 933          */
 934         function makeList( $a, $mode = LIST_COMMA ) {
 935                 if ( !is_array( $a ) ) {
 936                         wfDebugDieBacktrace( 'Database::makeList called with incorrect parameters' );
 937                 }
 938
 939                 $first = true;
 940                 $list = '';
 941                 foreach ( $a as $field => $value ) {
 942                         if ( !$first ) {
 943                                 if ( $mode == LIST_AND ) {
 944                                         $list .= ' AND ';
 945                                 } else {
 946                                         $list .= ',';
 947                                 }
 948                         } else {
 949                                 $first = false;
 950                         }
 951                         if ( $mode == LIST_AND && is_numeric( $field ) ) {
 952                                 $list .= "($value)";
 953                         } elseif ( $mode == LIST_AND && is_array ($value) ) {
 954                                 $list .= $field." IN (".$this->makeList($value).") ";
 955                         } else {
 956                                 if ( $mode == LIST_AND || $mode == LIST_SET ) {
 957                                         $list .= $field.'=';
 958                                 }
 959                                 $list .= ($mode==LIST_NAMES?$value:$this->addQuotes( $value ));
 960                         }
 961                 }
 962                 return $list;
 963         }
 964
 965         /**
 966          * Change the current database
 967          */
 968         function selectDB( $db ) {
 969                 $this->mDBname = $db;
 970                 return mysql_select_db( $db, $this->mConn );
 971         }
 972
 973         /**
 974          * Starts a timer which will kill the DB thread after $timeout seconds
 975          */
 976         function startTimer( $timeout ) {
 977                 global $IP;
 978                 if( function_exists( 'mysql_thread_id' ) ) {
 979                         # This will kill the query if it's still running after $timeout seconds.
 980                         $tid = mysql_thread_id( $this->mConn );
 981                         exec( "php $IP/includes/killthread.php $timeout $tid &>/dev/null &" );
 982                 }
 983         }
 984
 985         /**
 986          * Stop a timer started by startTimer()
 987          * Currently unimplemented.
 988          *
 989          */
 990         function stopTimer() { }
 991
 992         /**
 993          * Format a table name ready for use in constructing an SQL query
 994          *
 995          * This does two important things: it quotes table names which as necessary,
 996          * and it adds a table prefix if there is one.
 997          *
 998          * All functions of this object which require a table name call this function
 999          * themselves. Pass the canonical name to such functions. This is only needed
1000          * when calling query() directly.
1001          *
1002          * @param string $name database table name
1003          */
1004         function tableName( $name ) {
1005                 global $wgSharedDB;
1006                 # Skip quoted literals
1007                 if ( $name{0} != '`' ) {
1008                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1009                                 $name = "{$this->mTablePrefix}$name";
1010                         }
1011                         if ( isset( $wgSharedDB ) && 'user' == $name ) {
1012                                 $name = "`$wgSharedDB`.`$name`";
1013                         } else {
1014                                 # Standard quoting
1015                                 $name = "`$name`";
1016                         }
1017                 }
1018                 return $name;
1019         }
1020
1021         /**
1022          * Fetch a number of table names into an array
1023          * This is handy when you need to construct SQL for joins
1024          *
1025          * Example:
1026          * extract($dbr->tableNames('user','watchlist'));
1027          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1028          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1029          */
1030         function tableNames() {
1031                 $inArray = func_get_args();
1032                 $retVal = array();
1033                 foreach ( $inArray as $name ) {
1034                         $retVal[$name] = $this->tableName( $name );
1035                 }
1036                 return $retVal;
1037         }
1038
1039         /**
1040          * Wrapper for addslashes()
1041          * @param string $s String to be slashed.
1042          * @return string slashed string.
1043          */
1044         function strencode( $s ) {
1045                 return addslashes( $s );
1046         }
1047
1048         /**
1049          * If it's a string, adds quotes and backslashes
1050          * Otherwise returns as-is
1051          */
1052         function addQuotes( $s ) {
1053                 if ( is_null( $s ) ) {
1054                         return 'NULL';
1055                 } else {
1056                         # This will also quote numeric values. This should be harmless,
1057                         # and protects against weird problems that occur when they really
1058                         # _are_ strings such as article titles and string->number->string
1059                         # conversion is not 1:1.
1060                         return "'" . $this->strencode( $s ) . "'";
1061                 }
1062         }
1063
1064         /**
1065          * Returns an appropriately quoted sequence value for inserting a new row.
1066          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1067          * subclass will return an integer, and save the value for insertId()
1068          */
1069         function nextSequenceValue( $seqName ) {
1070                 return NULL;
1071         }
1072
1073         /**
1074          * USE INDEX clause
1075          * PostgreSQL doesn't have them and returns ""
1076          */
1077         function useIndexClause( $index ) {
1078                 return "USE INDEX ($index)";
1079         }
1080
1081         /**
1082          * REPLACE query wrapper
1083          * PostgreSQL simulates this with a DELETE followed by INSERT
1084          * $row is the row to insert, an associative array
1085          * $uniqueIndexes is an array of indexes. Each element may be either a
1086          * field name or an array of field names
1087          *
1088          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1089          * However if you do this, you run the risk of encountering errors which wouldn't have
1090          * occurred in MySQL
1091          *
1092          * @todo migrate comment to phodocumentor format
1093          */
1094         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1095                 $table = $this->tableName( $table );
1096
1097                 # Single row case
1098                 if ( !is_array( reset( $rows ) ) ) {
1099                         $rows = array( $rows );
1100                 }
1101
1102                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1103                 $first = true;
1104                 foreach ( $rows as $row ) {
1105                         if ( $first ) {
1106                                 $first = false;
1107                         } else {
1108                                 $sql .= ',';
1109                         }
1110                         $sql .= '(' . $this->makeList( $row ) . ')';
1111                 }
1112                 return $this->query( $sql, $fname );
1113         }
1114
1115         /**
1116          * DELETE where the condition is a join
1117          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1118          *
1119          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1120          * join condition matches, set $conds='*'
1121          *
1122          * DO NOT put the join condition in $conds
1123          *
1124          * @param string $delTable The table to delete from.
1125          * @param string $joinTable The other table.
1126          * @param string $delVar The variable to join on, in the first table.
1127          * @param string $joinVar The variable to join on, in the second table.
1128          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1129          */
1130         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1131                 if ( !$conds ) {
1132                         wfDebugDieBacktrace( 'Database::deleteJoin() called with empty $conds' );
1133                 }
1134
1135                 $delTable = $this->tableName( $delTable );
1136                 $joinTable = $this->tableName( $joinTable );
1137                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1138                 if ( $conds != '*' ) {
1139                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1140                 }
1141
1142                 return $this->query( $sql, $fname );
1143         }
1144
1145         /**
1146          * Returns the size of a text field, or -1 for "unlimited"
1147          */
1148         function textFieldSize( $table, $field ) {
1149                 $table = $this->tableName( $table );
1150                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1151                 $res = $this->query( $sql, 'Database::textFieldSize' );
1152                 $row = $this->fetchObject( $res );
1153                 $this->freeResult( $res );
1154
1155                 if ( preg_match( "/\((.*)\)/", $row->Type, $m ) ) {
1156                         $size = $m[1];
1157                 } else {
1158                         $size = -1;
1159                 }
1160                 return $size;
1161         }
1162
1163         /**
1164          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1165          */
1166         function lowPriorityOption() {
1167                 return 'LOW_PRIORITY';
1168         }
1169
1170         /**
1171          * DELETE query wrapper
1172          *
1173          * Use $conds == "*" to delete all rows
1174          */
1175         function delete( $table, $conds, $fname = 'Database::delete' ) {
1176                 if ( !$conds ) {
1177                         wfDebugDieBacktrace( 'Database::delete() called with no conditions' );
1178                 }
1179                 $table = $this->tableName( $table );
1180                 $sql = "DELETE FROM $table";
1181                 if ( $conds != '*' ) {
1182                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1183                 }
1184                 return $this->query( $sql, $fname );
1185         }
1186
1187         /**
1188          * INSERT SELECT wrapper
1189          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1190          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1191          * $conds may be "*" to copy the whole table
1192          * srcTable may be an array of tables.
1193          */
1194         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect' ) {
1195                 $destTable = $this->tableName( $destTable );
1196                 if( is_array( $srcTable ) ) {
1197                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1198                 } else {
1199                         $srcTable = $this->tableName( $srcTable );
1200                 }
1201                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1202                         ' SELECT ' . implode( ',', $varMap ) .
1203                         " FROM $srcTable";
1204                 if ( $conds != '*' ) {
1205                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1206                 }
1207                 return $this->query( $sql, $fname );
1208         }
1209
1210         /**
1211          * Construct a LIMIT query with optional offset
1212          * This is used for query pages
1213          */
1214         function limitResult($limit,$offset) {
1215                 return ' LIMIT '.(is_numeric($offset)?"{$offset},":"")."{$limit} ";
1216         }
1217
1218         /**
1219          * Returns an SQL expression for a simple conditional.
1220          * Uses IF on MySQL.
1221          *
1222          * @param string $cond SQL expression which will result in a boolean value
1223          * @param string $trueVal SQL expression to return if true
1224          * @param string $falseVal SQL expression to return if false
1225          * @return string SQL fragment
1226          */
1227         function conditional( $cond, $trueVal, $falseVal ) {
1228                 return " IF($cond, $trueVal, $falseVal) ";
1229         }
1230
1231         /**
1232          * Determines if the last failure was due to a deadlock
1233          */
1234         function wasDeadlock() {
1235                 return $this->lastErrno() == 1213;
1236         }
1237
1238         /**
1239          * Perform a deadlock-prone transaction.
1240          *
1241          * This function invokes a callback function to perform a set of write
1242          * queries. If a deadlock occurs during the processing, the transaction
1243          * will be rolled back and the callback function will be called again.
1244          *
1245          * Usage:
1246          *   $dbw->deadlockLoop( callback, ... );
1247          *
1248          * Extra arguments are passed through to the specified callback function.
1249          *
1250          * Returns whatever the callback function returned on its successful,
1251          * iteration, or false on error, for example if the retry limit was
1252          * reached.
1253          */
1254         function deadlockLoop() {
1255                 $myFname = 'Database::deadlockLoop';
1256
1257                 $this->query( 'BEGIN', $myFname );
1258                 $args = func_get_args();
1259                 $function = array_shift( $args );
1260                 $oldIgnore = $this->ignoreErrors( true );
1261                 $tries = DEADLOCK_TRIES;
1262                 if ( is_array( $function ) ) {
1263                         $fname = $function[0];
1264                 } else {
1265                         $fname = $function;
1266                 }
1267                 do {
1268                         $retVal = call_user_func_array( $function, $args );
1269                         $error = $this->lastError();
1270                         $errno = $this->lastErrno();
1271                         $sql = $this->lastQuery();
1272
1273                         if ( $errno ) {
1274                                 if ( $this->wasDeadlock() ) {
1275                                         # Retry
1276                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1277                                 } else {
1278                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1279                                 }
1280                         }
1281                 } while( $this->wasDeadlock() && --$tries > 0 );
1282                 $this->ignoreErrors( $oldIgnore );
1283                 if ( $tries <= 0 ) {
1284                         $this->query( 'ROLLBACK', $myFname );
1285                         $this->reportQueryError( $error, $errno, $sql, $fname );
1286                         return false;
1287                 } else {
1288                         $this->query( 'COMMIT', $myFname );
1289                         return $retVal;
1290                 }
1291         }
1292
1293         /**
1294          * Do a SELECT MASTER_POS_WAIT()
1295          *
1296          * @param string $file the binlog file
1297          * @param string $pos the binlog position
1298          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1299          */
1300         function masterPosWait( $file, $pos, $timeout ) {
1301                 $fname = 'Database::masterPosWait';
1302                 wfProfileIn( $fname );
1303
1304
1305                 # Commit any open transactions
1306                 $this->immediateCommit();
1307
1308                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1309                 $encFile = $this->strencode( $file );
1310                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1311                 $res = $this->doQuery( $sql );
1312                 if ( $res && $row = $this->fetchRow( $res ) ) {
1313                         $this->freeResult( $res );
1314                         return $row[0];
1315                 } else {
1316                         return false;
1317                 }
1318         }
1319
1320         /**
1321          * Get the position of the master from SHOW SLAVE STATUS
1322          */
1323         function getSlavePos() {
1324                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1325                 $row = $this->fetchObject( $res );
1326                 if ( $row ) {
1327                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1328                 } else {
1329                         return array( false, false );
1330                 }
1331         }
1332
1333         /**
1334          * Get the position of the master from SHOW MASTER STATUS
1335          */
1336         function getMasterPos() {
1337                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1338                 $row = $this->fetchObject( $res );
1339                 if ( $row ) {
1340                         return array( $row->File, $row->Position );
1341                 } else {
1342                         return array( false, false );
1343                 }
1344         }
1345
1346         /**
1347          * Begin a transaction, or if a transaction has already started, continue it
1348          */
1349         function begin( $fname = 'Database::begin' ) {
1350                 if ( !$this->mTrxLevel ) {
1351                         $this->immediateBegin( $fname );
1352                 } else {
1353                         $this->mTrxLevel++;
1354                 }
1355         }
1356
1357         /**
1358          * End a transaction, or decrement the nest level if transactions are nested
1359          */
1360         function commit( $fname = 'Database::commit' ) {
1361                 if ( $this->mTrxLevel ) {
1362                         $this->mTrxLevel--;
1363                 }
1364                 if ( !$this->mTrxLevel ) {
1365                         $this->immediateCommit( $fname );
1366                 }
1367         }
1368
1369         /**
1370          * Rollback a transaction
1371          */
1372         function rollback( $fname = 'Database::rollback' ) {
1373                 $this->query( 'ROLLBACK', $fname );
1374                 $this->mTrxLevel = 0;
1375         }
1376
1377         /**
1378          * Begin a transaction, committing any previously open transaction
1379          */
1380         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1381                 $this->query( 'BEGIN', $fname );
1382                 $this->mTrxLevel = 1;
1383         }
1384
1385         /**
1386          * Commit transaction, if one is open
1387          */
1388         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1389                 $this->query( 'COMMIT', $fname );
1390                 $this->mTrxLevel = 0;
1391         }
1392
1393         /**
1394          * Return MW-style timestamp used for MySQL schema
1395          */
1396         function timestamp( $ts=0 ) {
1397                 return wfTimestamp(TS_MW,$ts);
1398         }
1399
1400         /**
1401          * Local database timestamp format or null
1402          */
1403         function timestampOrNull( $ts = null ) {
1404                 if( is_null( $ts ) ) {
1405                         return null;
1406                 } else {
1407                         return $this->timestamp( $ts );
1408                 }
1409         }
1410
1411         /**
1412          * @todo document
1413          */
1414         function &resultObject( &$result ) {
1415                 if( empty( $result ) ) {
1416                         return NULL;
1417                 } else {
1418                         return new ResultWrapper( $this, $result );
1419                 }
1420         }
1421
1422         /**
1423          * Return aggregated value alias
1424          */
1425         function aggregateValue ($valuedata,$valuename='value') {
1426                 return $valuename;
1427         }
1428
1429         /**
1430          * @return string wikitext of a link to the server software's web site
1431          */
1432         function getSoftwareLink() {
1433                 return "[http://www.mysql.com/ MySQL]";
1434         }
1435
1436         /**
1437          * @return string Version information from the database
1438          */
1439         function getServerVersion() {
1440                 return mysql_get_server_info();
1441         }
1442
1443         /**
1444          * Ping the server and try to reconnect if it there is no connection
1445          */
1446         function ping() {
1447                 return mysql_ping( $this->mConn );
1448         }
1449 }
1450
1451 /**
1452  * Database abstraction object for mySQL
1453  * Inherit all methods and properties of Database::Database()
1454  *
1455  * @package MediaWiki
1456  * @see Database
1457  */
1458 class DatabaseMysql extends Database {
1459         # Inherit all
1460 }
1461
1462
1463 /**
1464  * Result wrapper for grabbing data queried by someone else
1465  *
1466  * @package MediaWiki
1467  */
1468 class ResultWrapper {
1469         var $db, $result;
1470
1471         /**
1472          * @todo document
1473          */
1474         function ResultWrapper( $database, $result ) {
1475                 $this->db =& $database;
1476                 $this->result =& $result;
1477         }
1478
1479         /**
1480          * @todo document
1481          */
1482         function numRows() {
1483                 return $this->db->numRows( $this->result );
1484         }
1485
1486         /**
1487          * @todo document
1488          */
1489         function &fetchObject() {
1490                 return $this->db->fetchObject( $this->result );
1491         }
1492
1493         /**
1494          * @todo document
1495          */
1496         function &fetchRow() {
1497                 return $this->db->fetchRow( $this->result );
1498         }
1499
1500         /**
1501          * @todo document
1502          */
1503         function free() {
1504                 $this->db->freeResult( $this->result );
1505                 unset( $this->result );
1506                 unset( $this->db );
1507         }
1508
1509         function seek( $row ) {
1510                 $this->db->dataSeek( $this->result, $row );
1511         }
1512 }
1513
1514 #------------------------------------------------------------------------------
1515 # Global functions
1516 #------------------------------------------------------------------------------
1517
1518 /**
1519  * Standard fail function, called by default when a connection cannot be
1520  * established.
1521  * Displays the file cache if possible
1522  */
1523 function wfEmergencyAbort( &$conn, $error ) {
1524         global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgOutputEncoding;
1525         global $wgSitename, $wgServer;
1526
1527         # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
1528         # Hard coding strings instead.
1529
1530         $noconnect = 'Sorry! The wiki is experiencing some technical difficulties, and cannot contact the database server. <br />
1531 $1';
1532         $mainpage = 'Main Page';
1533         $searchdisabled = <<<EOT
1534 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
1535 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
1536 EOT;
1537
1538         $googlesearch = "
1539 <!-- SiteSearch Google -->
1540 <FORM method=GET action=\"http://www.google.com/search\">
1541 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
1542 <A HREF=\"http://www.google.com/\">
1543 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
1544 border=\"0\" ALT=\"Google\"></A>
1545 </td>
1546 <td>
1547 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
1548 <INPUT type=submit name=btnG VALUE=\"Google Search\">
1549 <font size=-1>
1550 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
1551 <input type='hidden' name='ie' value='$2'>
1552 <input type='hidden' name='oe' value='$2'>
1553 </font>
1554 </td></tr></TABLE>
1555 </FORM>
1556 <!-- SiteSearch Google -->";
1557         $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
1558
1559
1560         if( !headers_sent() ) {
1561                 header( 'HTTP/1.0 500 Internal Server Error' );
1562                 header( 'Content-type: text/html; charset='.$wgOutputEncoding );
1563                 /* Don't cache error pages!  They cause no end of trouble... */
1564                 header( 'Cache-control: none' );
1565                 header( 'Pragma: nocache' );
1566         }
1567         $msg = wfGetSiteNotice();
1568         if($msg == '') {
1569                 $msg = str_replace( '$1', $error, $noconnect );
1570         }
1571         $text = $msg;
1572
1573         if($wgUseFileCache) {
1574                 if($wgTitle) {
1575                         $t =& $wgTitle;
1576                 } else {
1577                         if($title) {
1578                                 $t = Title::newFromURL( $title );
1579                         } elseif (@/**/$_REQUEST['search']) {
1580                                 $search = $_REQUEST['search'];
1581                                 echo $searchdisabled;
1582                                 echo str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
1583                                   $wgInputEncoding ), $googlesearch );
1584                                 wfErrorExit();
1585                         } else {
1586                                 $t = Title::newFromText( $mainpage );
1587                         }
1588                 }
1589
1590                 $cache = new CacheManager( $t );
1591                 if( $cache->isFileCached() ) {
1592                         $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
1593                                 $cachederror . "</b></p>\n";
1594
1595                         $tag = '<div id="article">';
1596                         $text = str_replace(
1597                                 $tag,
1598                                 $tag . $msg,
1599                                 $cache->fetchPageText() );
1600                 }
1601         }
1602
1603         echo $text;
1604         wfErrorExit();
1605 }
1606
1607 ?>