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, $password );
 216                 } else {
 217                         # Create a new connection...
 218                         @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 219                 }
 220
 221                 if ( $dbName != '' ) {
 222                         if ( $this->mConn !== false ) {
 223                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 224                                 if ( !$success ) {
 225                                         wfDebug( "Error selecting database \"$dbName\": " . $this->lastError() . "\n" );
 226                                 }
 227                         } else {
 228                                 wfDebug( "DB connection error\n" );
 229                                 wfDebug( "Server: $server, User: $user, Password: " .
 230                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 231                                 $success = false;
 232                         }
 233                 } else {
 234                         # Delay USE query
 235                         $success = (bool)$this->mConn;
 236                 }
 237
 238                 if ( !$success ) {
 239                         $this->reportConnectionError();
 240                         $this->close();
 241                 }
 242                 $this->mOpened = $success;
 243                 return $success;
 244         }
 245         /**#@-*/
 246
 247         /**
 248          * Closes a database connection.
 249          * if it is open : commits any open transactions
 250          *
 251          * @return bool operation success. true if already closed.
 252          */
 253         function close()
 254         {
 255                 $this->mOpened = false;
 256                 if ( $this->mConn ) {
 257                         if ( $this->trxLevel() ) {
 258                                 $this->immediateCommit();
 259                         }
 260                         return mysql_close( $this->mConn );
 261                 } else {
 262                         return true;
 263                 }
 264         }
 265
 266         /**
 267          * @access private
 268          * @param string $msg error message ?
 269          * @todo parameter $msg is not used
 270          */
 271         function reportConnectionError( $msg = '') {
 272                 if ( $this->mFailFunction ) {
 273                         if ( !is_int( $this->mFailFunction ) ) {
 274                                 $ff = $this->mFailFunction;
 275                                 $ff( $this, mysql_error() );
 276                         }
 277                 } else {
 278                         wfEmergencyAbort( $this, mysql_error() );
 279                 }
 280         }
 281
 282         /**
 283          * Usually aborts on failure
 284          * If errors are explicitly ignored, returns success
 285          */
 286         function query( $sql, $fname = '', $tempIgnore = false ) {
 287                 global $wgProfiling, $wgCommandLineMode;
 288
 289                 if ( wfReadOnly() ) {
 290                         # This is a quick check for the most common kinds of write query used
 291                         # in MediaWiki, to provide extra safety in addition to UI-level checks.
 292                         # It is not intended to prevent every conceivable write query, or even
 293                         # to handle such queries gracefully.
 294                         if ( preg_match( '/^(update|insert|replace|delete)/i', $sql ) ) {
 295                                 wfDebug( "Write query from $fname blocked\n" );
 296                                 return false;
 297                         }
 298                 }
 299
 300                 if ( $wgProfiling ) {
 301                         # generalizeSQL will probably cut down the query to reasonable
 302                         # logging size most of the time. The substr is really just a sanity check.
 303                         $profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 304                         wfProfileIn( 'Database::query' );
 305                         wfProfileIn( $profName );
 306                 }
 307
 308                 $this->mLastQuery = $sql;
 309
 310                 # Add a comment for easy SHOW PROCESSLIST interpretation
 311                 if ( $fname ) {
 312                         $commentedSql = "/* $fname */ $sql";
 313                 } else {
 314                         $commentedSql = $sql;
 315                 }
 316
 317                 # If DBO_TRX is set, start a transaction
 318                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() && $sql != 'BEGIN' ) {
 319                         $this->begin();
 320                 }
 321
 322                 if ( $this->debug() ) {
 323                         $sqlx = substr( $commentedSql, 0, 500 );
 324                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 325                         wfDebug( "SQL: $sqlx\n" );
 326                 }
 327
 328                 # Do the query and handle errors
 329                 $ret = $this->doQuery( $commentedSql );
 330
 331                 # Try reconnecting if the connection was lost
 332                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 333                         # Transaction is gone, like it or not
 334                         $this->mTrxLevel = 0;
 335                         wfDebug( "Connection lost, reconnecting...\n" );
 336                         if ( $this->ping() ) {
 337                                 wfDebug( "Reconnected\n" );
 338                                 $ret = $this->doQuery( $commentedSql );
 339                         } else {
 340                                 wfDebug( "Failed\n" );
 341                         }
 342                 }
 343
 344                 if ( false === $ret ) {
 345                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 346                 }
 347
 348                 if ( $wgProfiling ) {
 349                         wfProfileOut( $profName );
 350                         wfProfileOut( 'Database::query' );
 351                 }
 352                 return $ret;
 353         }
 354
 355         /**
 356          * The DBMS-dependent part of query()
 357          * @param string $sql SQL query.
 358          */
 359         function doQuery( $sql ) {
 360                 if( $this->bufferResults() ) {
 361                         $ret = mysql_query( $sql, $this->mConn );
 362                 } else {
 363                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 364                 }
 365                 return $ret;
 366         }
 367
 368         /**
 369          * @param $error
 370          * @param $errno
 371          * @param $sql
 372          * @param string $fname
 373          * @param bool $tempIgnore
 374          */
 375         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 376                 global $wgCommandLineMode, $wgFullyInitialised;
 377                 # Ignore errors during error handling to avoid infinite recursion
 378                 $ignore = $this->ignoreErrors( true );
 379                 $this->mErrorCount ++;
 380
 381                 if( $ignore || $tempIgnore ) {
 382                         wfDebug("SQL ERROR (ignored): " . $error . "\n");
 383                 } else {
 384                         $sql1line = str_replace( "\n", "\\n", $sql );
 385                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 386                         wfDebug("SQL ERROR: " . $error . "\n");
 387                         if ( $wgCommandLineMode || !$this->mOut || empty( $wgFullyInitialised ) ) {
 388                                 $message = "A database error has occurred\n" .
 389                                   "Query: $sql\n" .
 390                                   "Function: $fname\n" .
 391                                   "Error: $errno $error\n";
 392                                 if ( !$wgCommandLineMode ) {
 393                                         $message = nl2br( $message );
 394                                 }
 395                                 wfDebugDieBacktrace( $message );
 396                         } else {
 397                                 // this calls wfAbruptExit()
 398                                 $this->mOut->databaseError( $fname, $sql, $error, $errno );
 399                         }
 400                 }
 401                 $this->ignoreErrors( $ignore );
 402         }
 403
 404
 405         /**
 406          * Intended to be compatible with the PEAR::DB wrapper functions.
 407          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 408          *
 409          * ? = scalar value, quoted as necessary
 410          * ! = raw SQL bit (a function for instance)
 411          * & = filename; reads the file and inserts as a blob
 412          *     (we don't use this though...)
 413          */
 414         function prepare( $sql, $func = 'Database::prepare' ) {
 415                 /* MySQL doesn't support prepared statements (yet), so just
 416                    pack up the query for reference. We'll manually replace
 417                    the bits later. */
 418                 return array( 'query' => $sql, 'func' => $func );
 419         }
 420
 421         function freePrepared( $prepared ) {
 422                 /* No-op for MySQL */
 423         }
 424
 425         /**
 426          * Execute a prepared query with the various arguments
 427          * @param string $prepared the prepared sql
 428          * @param mixed $args Either an array here, or put scalars as varargs
 429          */
 430         function execute( $prepared, $args = null ) {
 431                 if( !is_array( $args ) ) {
 432                         # Pull the var args
 433                         $args = func_get_args();
 434                         array_shift( $args );
 435                 }
 436                 $sql = $this->fillPrepared( $prepared['query'], $args );
 437                 return $this->query( $sql, $prepared['func'] );
 438         }
 439
 440         /**
 441          * Prepare & execute an SQL statement, quoting and inserting arguments
 442          * in the appropriate places.
 443          * @param string $query
 444          * @param string $args ...
 445          */
 446         function safeQuery( $query, $args = null ) {
 447                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 448                 if( !is_array( $args ) ) {
 449                         # Pull the var args
 450                         $args = func_get_args();
 451                         array_shift( $args );
 452                 }
 453                 $retval = $this->execute( $prepared, $args );
 454                 $this->freePrepared( $prepared );
 455                 return $retval;
 456         }
 457
 458         /**
 459          * For faking prepared SQL statements on DBs that don't support
 460          * it directly.
 461          * @param string $preparedSql - a 'preparable' SQL statement
 462          * @param array $args - array of arguments to fill it with
 463          * @return string executable SQL
 464          */
 465         function fillPrepared( $preparedQuery, $args ) {
 466                 $n = 0;
 467                 reset( $args );
 468                 $this->preparedArgs =& $args;
 469                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 470                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 471         }
 472
 473         /**
 474          * preg_callback func for fillPrepared()
 475          * The arguments should be in $this->preparedArgs and must not be touched
 476          * while we're doing this.
 477          *
 478          * @param array $matches
 479          * @return string
 480          * @access private
 481          */
 482         function fillPreparedArg( $matches ) {
 483                 switch( $matches[1] ) {
 484                         case '\\?': return '?';
 485                         case '\\!': return '!';
 486                         case '\\&': return '&';
 487                 }
 488                 list( $n, $arg ) = each( $this->preparedArgs );
 489                 switch( $matches[1] ) {
 490                         case '?': return $this->addQuotes( $arg );
 491                         case '!': return $arg;
 492                         case '&':
 493                                 # return $this->addQuotes( file_get_contents( $arg ) );
 494                                 wfDebugDieBacktrace( '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 495                         default:
 496                                 wfDebugDieBacktrace( 'Received invalid match. This should never happen!' );
 497                 }
 498         }
 499
 500         /**#@+
 501          * @param mixed $res A SQL result
 502          */
 503         /**
 504          * Free a result object
 505          */
 506         function freeResult( $res ) {
 507                 if ( !@/**/mysql_free_result( $res ) ) {
 508                         wfDebugDieBacktrace( "Unable to free MySQL result\n" );
 509                 }
 510         }
 511
 512         /**
 513          * Fetch the next row from the given result object, in object form
 514          */
 515         function fetchObject( $res ) {
 516                 @/**/$row = mysql_fetch_object( $res );
 517                 if( mysql_errno() ) {
 518                         wfDebugDieBacktrace( 'Error in fetchObject(): ' . htmlspecialchars( mysql_error() ) );
 519                 }
 520                 return $row;
 521         }
 522
 523         /**
 524          * Fetch the next row from the given result object
 525          * Returns an array
 526          */
 527         function fetchRow( $res ) {
 528                 @/**/$row = mysql_fetch_array( $res );
 529                 if (mysql_errno() ) {
 530                         wfDebugDieBacktrace( 'Error in fetchRow(): ' . htmlspecialchars( mysql_error() ) );
 531                 }
 532                 return $row;
 533         }
 534
 535         /**
 536          * Get the number of rows in a result object
 537          */
 538         function numRows( $res ) {
 539                 @/**/$n = mysql_num_rows( $res );
 540                 if( mysql_errno() ) {
 541                         wfDebugDieBacktrace( 'Error in numRows(): ' . htmlspecialchars( mysql_error() ) );
 542                 }
 543                 return $n;
 544         }
 545
 546         /**
 547          * Get the number of fields in a result object
 548          * See documentation for mysql_num_fields()
 549          */
 550         function numFields( $res ) { return mysql_num_fields( $res ); }
 551
 552         /**
 553          * Get a field name in a result object
 554          * See documentation for mysql_field_name()
 555          */
 556         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 557
 558         /**
 559          * Get the inserted value of an auto-increment row
 560          *
 561          * The value inserted should be fetched from nextSequenceValue()
 562          *
 563          * Example:
 564          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 565          * $dbw->insert('page',array('page_id' => $id));
 566          * $id = $dbw->insertId();
 567          */
 568         function insertId() { return mysql_insert_id( $this->mConn ); }
 569
 570         /**
 571          * Change the position of the cursor in a result object
 572          * See mysql_data_seek()
 573          */
 574         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 575
 576         /**
 577          * Get the last error number
 578          * See mysql_errno()
 579          */
 580         function lastErrno() {
 581                 if ( $this->mConn ) {
 582                         return mysql_errno( $this->mConn );
 583                 } else {
 584                         return mysql_errno();
 585                 }
 586         }
 587
 588         /**
 589          * Get a description of the last error
 590          * See mysql_error() for more details
 591          */
 592         function lastError() {
 593                 if ( $this->mConn ) {
 594                         $error = mysql_error( $this->mConn );
 595                 } else {
 596                         $error = mysql_error();
 597                 }
 598                 if( $error ) {
 599                         $error .= ' (' . $this->mServer . ')';
 600                 }
 601                 return $error;
 602         }
 603         /**
 604          * Get the number of rows affected by the last write query
 605          * See mysql_affected_rows() for more details
 606          */
 607         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 608         /**#@-*/ // end of template : @param $result
 609
 610         /**
 611          * Simple UPDATE wrapper
 612          * Usually aborts on failure
 613          * If errors are explicitly ignored, returns success
 614          *
 615          * This function exists for historical reasons, Database::update() has a more standard
 616          * calling convention and feature set
 617          */
 618         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 619         {
 620                 $table = $this->tableName( $table );
 621                 $sql = "UPDATE $table SET $var = '" .
 622                   $this->strencode( $value ) . "' WHERE ($cond)";
 623                 return (bool)$this->query( $sql, DB_MASTER, $fname );
 624         }
 625
 626         /**
 627          * Simple SELECT wrapper, returns a single field, input must be encoded
 628          * Usually aborts on failure
 629          * If errors are explicitly ignored, returns FALSE on failure
 630          */
 631         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 632                 if ( !is_array( $options ) ) {
 633                         $options = array( $options );
 634                 }
 635                 $options['LIMIT'] = 1;
 636
 637                 $res = $this->select( $table, $var, $cond, $fname, $options );
 638                 if ( $res === false || !$this->numRows( $res ) ) {
 639                         return false;
 640                 }
 641                 $row = $this->fetchRow( $res );
 642                 if ( $row !== false ) {
 643                         $this->freeResult( $res );
 644                         return $row[0];
 645                 } else {
 646                         return false;
 647                 }
 648         }
 649
 650         /**
 651          * Returns an optional USE INDEX clause to go after the table, and a
 652          * string to go at the end of the query
 653          *
 654          * @access private
 655          *
 656          * @param array $options an associative array of options to be turned into
 657          *              an SQL query, valid keys are listed in the function.
 658          * @return array
 659          */
 660         function makeSelectOptions( $options ) {
 661                 $tailOpts = '';
 662
 663                 if ( isset( $options['GROUP BY'] ) ) {
 664                         $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 665                 }
 666                 if ( isset( $options['ORDER BY'] ) ) {
 667                         $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 668                 }
 669                 if ( isset( $options['LIMIT'] ) ) {
 670                         $tailOpts .= " LIMIT {$options['LIMIT']}";
 671                 }
 672
 673                 if ( is_numeric( array_search( 'FOR UPDATE', $options ) ) ) {
 674                         $tailOpts .= ' FOR UPDATE';
 675                 }
 676
 677                 if ( is_numeric( array_search( 'LOCK IN SHARE MODE', $options ) ) ) {
 678                         $tailOpts .= ' LOCK IN SHARE MODE';
 679                 }
 680
 681                 if ( isset( $options['USE INDEX'] ) ) {
 682                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 683                 } else {
 684                         $useIndex = '';
 685                 }
 686                 return array( $useIndex, $tailOpts );
 687         }
 688
 689         /**
 690          * SELECT wrapper
 691          */
 692         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
 693         {
 694                 if( is_array( $vars ) ) {
 695                         $vars = implode( ',', $vars );
 696                 }
 697                 if( is_array( $table ) ) {
 698                         $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 699                 } elseif ($table!='') {
 700                         $from = ' FROM ' .$this->tableName( $table );
 701                 } else {
 702                         $from = '';
 703                 }
 704
 705                 list( $useIndex, $tailOpts ) = $this->makeSelectOptions( (array)$options );
 706
 707                 if( !empty( $conds ) ) {
 708                         if ( is_array( $conds ) ) {
 709                                 $conds = $this->makeList( $conds, LIST_AND );
 710                         }
 711                         $sql = "SELECT $vars $from $useIndex WHERE $conds $tailOpts";
 712                 } else {
 713                         $sql = "SELECT $vars $from $useIndex $tailOpts";
 714                 }
 715                 return $this->query( $sql, $fname );
 716         }
 717
 718         /**
 719          * Single row SELECT wrapper
 720          * Aborts or returns FALSE on error
 721          *
 722          * $vars: the selected variables
 723          * $conds: a condition map, terms are ANDed together.
 724          *   Items with numeric keys are taken to be literal conditions
 725          * Takes an array of selected variables, and a condition map, which is ANDed
 726          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 727          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 728          * $obj- >page_id is the ID of the Astronomy article
 729          *
 730          * @todo migrate documentation to phpdocumentor format
 731          */
 732         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
 733                 $options['LIMIT'] = 1;
 734                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 735                 if ( $res === false || !$this->numRows( $res ) ) {
 736                         return false;
 737                 }
 738                 $obj = $this->fetchObject( $res );
 739                 $this->freeResult( $res );
 740                 return $obj;
 741
 742         }
 743
 744         /**
 745          * Removes most variables from an SQL query and replaces them with X or N for numbers.
 746          * It's only slightly flawed. Don't use for anything important.
 747          *
 748          * @param string $sql A SQL Query
 749          * @static
 750          */
 751         function generalizeSQL( $sql ) {
 752                 # This does the same as the regexp below would do, but in such a way
 753                 # as to avoid crashing php on some large strings.
 754                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
 755
 756                 $sql = str_replace ( "\\\\", '', $sql);
 757                 $sql = str_replace ( "\\'", '', $sql);
 758                 $sql = str_replace ( "\\\"", '', $sql);
 759                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
 760                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
 761
 762                 # All newlines, tabs, etc replaced by single space
 763                 $sql = preg_replace ( "/\s+/", ' ', $sql);
 764
 765                 # All numbers => N
 766                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
 767
 768                 return $sql;
 769         }
 770
 771         /**
 772          * Determines whether a field exists in a table
 773          * Usually aborts on failure
 774          * If errors are explicitly ignored, returns NULL on failure
 775          */
 776         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
 777                 $table = $this->tableName( $table );
 778                 $res = $this->query( 'DESCRIBE '.$table, DB_SLAVE, $fname );
 779                 if ( !$res ) {
 780                         return NULL;
 781                 }
 782
 783                 $found = false;
 784
 785                 while ( $row = $this->fetchObject( $res ) ) {
 786                         if ( $row->Field == $field ) {
 787                                 $found = true;
 788                                 break;
 789                         }
 790                 }
 791                 return $found;
 792         }
 793
 794         /**
 795          * Determines whether an index exists
 796          * Usually aborts on failure
 797          * If errors are explicitly ignored, returns NULL on failure
 798          */
 799         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
 800                 $info = $this->indexInfo( $table, $index, $fname );
 801                 if ( is_null( $info ) ) {
 802                         return NULL;
 803                 } else {
 804                         return $info !== false;
 805                 }
 806         }
 807
 808
 809         /**
 810          * Get information about an index into an object
 811          * Returns false if the index does not exist
 812          */
 813         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
 814                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 815                 # SHOW INDEX should work for 3.x and up:
 816                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 817                 $table = $this->tableName( $table );
 818                 $sql = 'SHOW INDEX FROM '.$table;
 819                 $res = $this->query( $sql, $fname );
 820                 if ( !$res ) {
 821                         return NULL;
 822                 }
 823
 824                 while ( $row = $this->fetchObject( $res ) ) {
 825                         if ( $row->Key_name == $index ) {
 826                                 return $row;
 827                         }
 828                 }
 829                 return false;
 830         }
 831
 832         /**
 833          * Query whether a given table exists
 834          */
 835         function tableExists( $table ) {
 836                 $table = $this->tableName( $table );
 837                 $old = $this->ignoreErrors( true );
 838                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
 839                 $this->ignoreErrors( $old );
 840                 if( $res ) {
 841                         $this->freeResult( $res );
 842                         return true;
 843                 } else {
 844                         return false;
 845                 }
 846         }
 847
 848         /**
 849          * mysql_fetch_field() wrapper
 850          * Returns false if the field doesn't exist
 851          *
 852          * @param $table
 853          * @param $field
 854          */
 855         function fieldInfo( $table, $field ) {
 856                 $table = $this->tableName( $table );
 857                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
 858                 $n = mysql_num_fields( $res );
 859                 for( $i = 0; $i < $n; $i++ ) {
 860                         $meta = mysql_fetch_field( $res, $i );
 861                         if( $field == $meta->name ) {
 862                                 return $meta;
 863                         }
 864                 }
 865                 return false;
 866         }
 867
 868         /**
 869          * mysql_field_type() wrapper
 870          */
 871         function fieldType( $res, $index ) {
 872                 return mysql_field_type( $res, $index );
 873         }
 874
 875         /**
 876          * Determines if a given index is unique
 877          */
 878         function indexUnique( $table, $index ) {
 879                 $indexInfo = $this->indexInfo( $table, $index );
 880                 if ( !$indexInfo ) {
 881                         return NULL;
 882                 }
 883                 return !$indexInfo->Non_unique;
 884         }
 885
 886         /**
 887          * INSERT wrapper, inserts an array into a table
 888          *
 889          * $a may be a single associative array, or an array of these with numeric keys, for
 890          * multi-row insert.
 891          *
 892          * Usually aborts on failure
 893          * If errors are explicitly ignored, returns success
 894          */
 895         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
 896                 # No rows to insert, easy just return now
 897                 if ( !count( $a ) ) {
 898                         return true;
 899                 }
 900
 901                 $table = $this->tableName( $table );
 902                 if ( !is_array( $options ) ) {
 903                         $options = array( $options );
 904                 }
 905                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 906                         $multi = true;
 907                         $keys = array_keys( $a[0] );
 908                 } else {
 909                         $multi = false;
 910                         $keys = array_keys( $a );
 911                 }
 912
 913                 $sql = 'INSERT ' . implode( ' ', $options ) .
 914                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 915
 916                 if ( $multi ) {
 917                         $first = true;
 918                         foreach ( $a as $row ) {
 919                                 if ( $first ) {
 920                                         $first = false;
 921                                 } else {
 922                                         $sql .= ',';
 923                                 }
 924                                 $sql .= '(' . $this->makeList( $row ) . ')';
 925                         }
 926                 } else {
 927                         $sql .= '(' . $this->makeList( $a ) . ')';
 928                 }
 929                 return (bool)$this->query( $sql, $fname );
 930         }
 931
 932         /**
 933          * Make UPDATE options for the Database::update function
 934          *
 935          * @access private
 936          * @param array $options The options passed to Database::update
 937          * @return string
 938          */
 939         function makeUpdateOptions( $options ) {
 940                 if( !is_array( $options ) ) {
 941                         wfDebugDieBacktrace( 'makeUpdateOptions given non-array' );
 942                 }
 943                 $opts = array();
 944                 if ( in_array( 'LOW_PRIORITY', $options ) )
 945                         $opts[] = $this->lowPriorityOption();
 946                 if ( in_array( 'IGNORE', $options ) )
 947                         $opts[] = 'IGNORE';
 948                 return implode(' ', $opts);
 949         }
 950
 951         /**
 952          * UPDATE wrapper, takes a condition array and a SET array
 953          *
 954          * @param string $table  The table to UPDATE
 955          * @param array  $values An array of values to SET
 956          * @param array  $conds  An array of conditions (WHERE)
 957          * @param string $fname  The Class::Function calling this function
 958          *                       (for the log)
 959          * @param array  $options An array of UPDATE options, can be one or
 960          *                        more of IGNORE, LOW_PRIORITY
 961          */
 962         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
 963                 $table = $this->tableName( $table );
 964                 $opts = $this->makeUpdateOptions( $options );
 965                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
 966                 if ( $conds != '*' ) {
 967                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
 968                 }
 969                 $this->query( $sql, $fname );
 970         }
 971
 972         /**
 973          * Makes a wfStrencoded list from an array
 974          * $mode: LIST_COMMA         - comma separated, no field names
 975          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
 976          *        LIST_SET           - comma separated with field names, like a SET clause
 977          *        LIST_NAMES         - comma separated field names
 978          */
 979         function makeList( $a, $mode = LIST_COMMA ) {
 980                 if ( !is_array( $a ) ) {
 981                         wfDebugDieBacktrace( 'Database::makeList called with incorrect parameters' );
 982                 }
 983
 984                 $first = true;
 985                 $list = '';
 986                 foreach ( $a as $field => $value ) {
 987                         if ( !$first ) {
 988                                 if ( $mode == LIST_AND ) {
 989                                         $list .= ' AND ';
 990                                 } else {
 991                                         $list .= ',';
 992                                 }
 993                         } else {
 994                                 $first = false;
 995                         }
 996                         if ( $mode == LIST_AND && is_numeric( $field ) ) {
 997                                 $list .= "($value)";
 998                         } elseif ( $mode == LIST_AND && is_array ($value) ) {
 999                                 $list .= $field." IN (".$this->makeList($value).") ";
1000                         } else {
1001                                 if ( $mode == LIST_AND || $mode == LIST_SET ) {
1002                                         $list .= "$field = ";
1003                                 }
1004                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1005                         }
1006                 }
1007                 return $list;
1008         }
1009
1010         /**
1011          * Change the current database
1012          */
1013         function selectDB( $db ) {
1014                 $this->mDBname = $db;
1015                 return mysql_select_db( $db, $this->mConn );
1016         }
1017
1018         /**
1019          * Starts a timer which will kill the DB thread after $timeout seconds
1020          */
1021         function startTimer( $timeout ) {
1022                 global $IP;
1023                 if( function_exists( 'mysql_thread_id' ) ) {
1024                         # This will kill the query if it's still running after $timeout seconds.
1025                         $tid = mysql_thread_id( $this->mConn );
1026                         exec( "php $IP/includes/killthread.php $timeout $tid &>/dev/null &" );
1027                 }
1028         }
1029
1030         /**
1031          * Stop a timer started by startTimer()
1032          * Currently unimplemented.
1033          *
1034          */
1035         function stopTimer() { }
1036
1037         /**
1038          * Format a table name ready for use in constructing an SQL query
1039          *
1040          * This does two important things: it quotes table names which as necessary,
1041          * and it adds a table prefix if there is one.
1042          *
1043          * All functions of this object which require a table name call this function
1044          * themselves. Pass the canonical name to such functions. This is only needed
1045          * when calling query() directly.
1046          *
1047          * @param string $name database table name
1048          */
1049         function tableName( $name ) {
1050                 global $wgSharedDB;
1051                 # Skip quoted literals
1052                 if ( $name{0} != '`' ) {
1053                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1054                                 $name = "{$this->mTablePrefix}$name";
1055                         }
1056                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1057                                 $name = "`$wgSharedDB`.`$name`";
1058                         } else {
1059                                 # Standard quoting
1060                                 $name = "`$name`";
1061                         }
1062                 }
1063                 return $name;
1064         }
1065
1066         /**
1067          * Fetch a number of table names into an array
1068          * This is handy when you need to construct SQL for joins
1069          *
1070          * Example:
1071          * extract($dbr->tableNames('user','watchlist'));
1072          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1073          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1074          */
1075         function tableNames() {
1076                 $inArray = func_get_args();
1077                 $retVal = array();
1078                 foreach ( $inArray as $name ) {
1079                         $retVal[$name] = $this->tableName( $name );
1080                 }
1081                 return $retVal;
1082         }
1083
1084         /**
1085          * Wrapper for addslashes()
1086          * @param string $s String to be slashed.
1087          * @return string slashed string.
1088          */
1089         function strencode( $s ) {
1090                 return addslashes( $s );
1091         }
1092
1093         /**
1094          * If it's a string, adds quotes and backslashes
1095          * Otherwise returns as-is
1096          */
1097         function addQuotes( $s ) {
1098                 if ( is_null( $s ) ) {
1099                         return 'NULL';
1100                 } else {
1101                         # This will also quote numeric values. This should be harmless,
1102                         # and protects against weird problems that occur when they really
1103                         # _are_ strings such as article titles and string->number->string
1104                         # conversion is not 1:1.
1105                         return "'" . $this->strencode( $s ) . "'";
1106                 }
1107         }
1108
1109         /**
1110          * Returns an appropriately quoted sequence value for inserting a new row.
1111          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1112          * subclass will return an integer, and save the value for insertId()
1113          */
1114         function nextSequenceValue( $seqName ) {
1115                 return NULL;
1116         }
1117
1118         /**
1119          * USE INDEX clause
1120          * PostgreSQL doesn't have them and returns ""
1121          */
1122         function useIndexClause( $index ) {
1123                 return "FORCE INDEX ($index)";
1124         }
1125
1126         /**
1127          * REPLACE query wrapper
1128          * PostgreSQL simulates this with a DELETE followed by INSERT
1129          * $row is the row to insert, an associative array
1130          * $uniqueIndexes is an array of indexes. Each element may be either a
1131          * field name or an array of field names
1132          *
1133          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1134          * However if you do this, you run the risk of encountering errors which wouldn't have
1135          * occurred in MySQL
1136          *
1137          * @todo migrate comment to phodocumentor format
1138          */
1139         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1140                 $table = $this->tableName( $table );
1141
1142                 # Single row case
1143                 if ( !is_array( reset( $rows ) ) ) {
1144                         $rows = array( $rows );
1145                 }
1146
1147                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1148                 $first = true;
1149                 foreach ( $rows as $row ) {
1150                         if ( $first ) {
1151                                 $first = false;
1152                         } else {
1153                                 $sql .= ',';
1154                         }
1155                         $sql .= '(' . $this->makeList( $row ) . ')';
1156                 }
1157                 return $this->query( $sql, $fname );
1158         }
1159
1160         /**
1161          * DELETE where the condition is a join
1162          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1163          *
1164          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1165          * join condition matches, set $conds='*'
1166          *
1167          * DO NOT put the join condition in $conds
1168          *
1169          * @param string $delTable The table to delete from.
1170          * @param string $joinTable The other table.
1171          * @param string $delVar The variable to join on, in the first table.
1172          * @param string $joinVar The variable to join on, in the second table.
1173          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1174          */
1175         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1176                 if ( !$conds ) {
1177                         wfDebugDieBacktrace( 'Database::deleteJoin() called with empty $conds' );
1178                 }
1179
1180                 $delTable = $this->tableName( $delTable );
1181                 $joinTable = $this->tableName( $joinTable );
1182                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1183                 if ( $conds != '*' ) {
1184                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1185                 }
1186
1187                 return $this->query( $sql, $fname );
1188         }
1189
1190         /**
1191          * Returns the size of a text field, or -1 for "unlimited"
1192          */
1193         function textFieldSize( $table, $field ) {
1194                 $table = $this->tableName( $table );
1195                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1196                 $res = $this->query( $sql, 'Database::textFieldSize' );
1197                 $row = $this->fetchObject( $res );
1198                 $this->freeResult( $res );
1199
1200                 if ( preg_match( "/\((.*)\)/", $row->Type, $m ) ) {
1201                         $size = $m[1];
1202                 } else {
1203                         $size = -1;
1204                 }
1205                 return $size;
1206         }
1207
1208         /**
1209          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1210          */
1211         function lowPriorityOption() {
1212                 return 'LOW_PRIORITY';
1213         }
1214
1215         /**
1216          * DELETE query wrapper
1217          *
1218          * Use $conds == "*" to delete all rows
1219          */
1220         function delete( $table, $conds, $fname = 'Database::delete' ) {
1221                 if ( !$conds ) {
1222                         wfDebugDieBacktrace( 'Database::delete() called with no conditions' );
1223                 }
1224                 $table = $this->tableName( $table );
1225                 $sql = "DELETE FROM $table";
1226                 if ( $conds != '*' ) {
1227                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1228                 }
1229                 return $this->query( $sql, $fname );
1230         }
1231
1232         /**
1233          * INSERT SELECT wrapper
1234          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1235          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1236          * $conds may be "*" to copy the whole table
1237          * srcTable may be an array of tables.
1238          */
1239         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect' ) {
1240                 $destTable = $this->tableName( $destTable );
1241                 if( is_array( $srcTable ) ) {
1242                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1243                 } else {
1244                         $srcTable = $this->tableName( $srcTable );
1245                 }
1246                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1247                         ' SELECT ' . implode( ',', $varMap ) .
1248                         " FROM $srcTable";
1249                 if ( $conds != '*' ) {
1250                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1251                 }
1252                 return $this->query( $sql, $fname );
1253         }
1254
1255         /**
1256          * Construct a LIMIT query with optional offset
1257          * This is used for query pages
1258          */
1259         function limitResult($limit,$offset) {
1260                 return ' LIMIT '.(is_numeric($offset)?"{$offset},":"")."{$limit} ";
1261         }
1262
1263         /**
1264          * Returns an SQL expression for a simple conditional.
1265          * Uses IF on MySQL.
1266          *
1267          * @param string $cond SQL expression which will result in a boolean value
1268          * @param string $trueVal SQL expression to return if true
1269          * @param string $falseVal SQL expression to return if false
1270          * @return string SQL fragment
1271          */
1272         function conditional( $cond, $trueVal, $falseVal ) {
1273                 return " IF($cond, $trueVal, $falseVal) ";
1274         }
1275
1276         /**
1277          * Determines if the last failure was due to a deadlock
1278          */
1279         function wasDeadlock() {
1280                 return $this->lastErrno() == 1213;
1281         }
1282
1283         /**
1284          * Perform a deadlock-prone transaction.
1285          *
1286          * This function invokes a callback function to perform a set of write
1287          * queries. If a deadlock occurs during the processing, the transaction
1288          * will be rolled back and the callback function will be called again.
1289          *
1290          * Usage:
1291          *   $dbw->deadlockLoop( callback, ... );
1292          *
1293          * Extra arguments are passed through to the specified callback function.
1294          *
1295          * Returns whatever the callback function returned on its successful,
1296          * iteration, or false on error, for example if the retry limit was
1297          * reached.
1298          */
1299         function deadlockLoop() {
1300                 $myFname = 'Database::deadlockLoop';
1301
1302                 $this->query( 'BEGIN', $myFname );
1303                 $args = func_get_args();
1304                 $function = array_shift( $args );
1305                 $oldIgnore = $this->ignoreErrors( true );
1306                 $tries = DEADLOCK_TRIES;
1307                 if ( is_array( $function ) ) {
1308                         $fname = $function[0];
1309                 } else {
1310                         $fname = $function;
1311                 }
1312                 do {
1313                         $retVal = call_user_func_array( $function, $args );
1314                         $error = $this->lastError();
1315                         $errno = $this->lastErrno();
1316                         $sql = $this->lastQuery();
1317
1318                         if ( $errno ) {
1319                                 if ( $this->wasDeadlock() ) {
1320                                         # Retry
1321                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1322                                 } else {
1323                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1324                                 }
1325                         }
1326                 } while( $this->wasDeadlock() && --$tries > 0 );
1327                 $this->ignoreErrors( $oldIgnore );
1328                 if ( $tries <= 0 ) {
1329                         $this->query( 'ROLLBACK', $myFname );
1330                         $this->reportQueryError( $error, $errno, $sql, $fname );
1331                         return false;
1332                 } else {
1333                         $this->query( 'COMMIT', $myFname );
1334                         return $retVal;
1335                 }
1336         }
1337
1338         /**
1339          * Do a SELECT MASTER_POS_WAIT()
1340          *
1341          * @param string $file the binlog file
1342          * @param string $pos the binlog position
1343          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1344          */
1345         function masterPosWait( $file, $pos, $timeout ) {
1346                 $fname = 'Database::masterPosWait';
1347                 wfProfileIn( $fname );
1348
1349
1350                 # Commit any open transactions
1351                 $this->immediateCommit();
1352
1353                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1354                 $encFile = $this->strencode( $file );
1355                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1356                 $res = $this->doQuery( $sql );
1357                 if ( $res && $row = $this->fetchRow( $res ) ) {
1358                         $this->freeResult( $res );
1359                         return $row[0];
1360                 } else {
1361                         return false;
1362                 }
1363         }
1364
1365         /**
1366          * Get the position of the master from SHOW SLAVE STATUS
1367          */
1368         function getSlavePos() {
1369                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1370                 $row = $this->fetchObject( $res );
1371                 if ( $row ) {
1372                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1373                 } else {
1374                         return array( false, false );
1375                 }
1376         }
1377
1378         /**
1379          * Get the position of the master from SHOW MASTER STATUS
1380          */
1381         function getMasterPos() {
1382                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1383                 $row = $this->fetchObject( $res );
1384                 if ( $row ) {
1385                         return array( $row->File, $row->Position );
1386                 } else {
1387                         return array( false, false );
1388                 }
1389         }
1390
1391         /**
1392          * Begin a transaction, or if a transaction has already started, continue it
1393          */
1394         function begin( $fname = 'Database::begin' ) {
1395                 if ( !$this->mTrxLevel ) {
1396                         $this->immediateBegin( $fname );
1397                 } else {
1398                         $this->mTrxLevel++;
1399                 }
1400         }
1401
1402         /**
1403          * End a transaction, or decrement the nest level if transactions are nested
1404          */
1405         function commit( $fname = 'Database::commit' ) {
1406                 if ( $this->mTrxLevel ) {
1407                         $this->mTrxLevel--;
1408                 }
1409                 if ( !$this->mTrxLevel ) {
1410                         $this->immediateCommit( $fname );
1411                 }
1412         }
1413
1414         /**
1415          * Rollback a transaction
1416          */
1417         function rollback( $fname = 'Database::rollback' ) {
1418                 $this->query( 'ROLLBACK', $fname );
1419                 $this->mTrxLevel = 0;
1420         }
1421
1422         /**
1423          * Begin a transaction, committing any previously open transaction
1424          */
1425         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1426                 $this->query( 'BEGIN', $fname );
1427                 $this->mTrxLevel = 1;
1428         }
1429
1430         /**
1431          * Commit transaction, if one is open
1432          */
1433         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1434                 $this->query( 'COMMIT', $fname );
1435                 $this->mTrxLevel = 0;
1436         }
1437
1438         /**
1439          * Return MW-style timestamp used for MySQL schema
1440          */
1441         function timestamp( $ts=0 ) {
1442                 return wfTimestamp(TS_MW,$ts);
1443         }
1444
1445         /**
1446          * Local database timestamp format or null
1447          */
1448         function timestampOrNull( $ts = null ) {
1449                 if( is_null( $ts ) ) {
1450                         return null;
1451                 } else {
1452                         return $this->timestamp( $ts );
1453                 }
1454         }
1455
1456         /**
1457          * @todo document
1458          */
1459         function resultObject( &$result ) {
1460                 if( empty( $result ) ) {
1461                         return NULL;
1462                 } else {
1463                         return new ResultWrapper( $this, $result );
1464                 }
1465         }
1466
1467         /**
1468          * Return aggregated value alias
1469          */
1470         function aggregateValue ($valuedata,$valuename='value') {
1471                 return $valuename;
1472         }
1473
1474         /**
1475          * @return string wikitext of a link to the server software's web site
1476          */
1477         function getSoftwareLink() {
1478                 return "[http://www.mysql.com/ MySQL]";
1479         }
1480
1481         /**
1482          * @return string Version information from the database
1483          */
1484         function getServerVersion() {
1485                 return mysql_get_server_info();
1486         }
1487
1488         /**
1489          * Ping the server and try to reconnect if it there is no connection
1490          */
1491         function ping() {
1492                 if( function_exists( 'mysql_ping' ) ) {
1493                         return mysql_ping( $this->mConn );
1494                 } else {
1495                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1496                         return true;
1497                 }
1498         }
1499
1500         /**
1501          * Get slave lag.
1502          * At the moment, this will only work if the DB user has the PROCESS privilege
1503          */
1504         function getLag() {
1505                 $res = $this->query( 'SHOW PROCESSLIST' );
1506                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1507                 # dubious, but unfortunately there's no easy rigorous way
1508                 $slaveThreads = 0;
1509                 while ( $row = $this->fetchObject( $res ) ) {
1510                         if ( $row->User == 'system user' ) {
1511                                 if ( ++$slaveThreads == 2 ) {
1512                                         # This is it, return the time
1513                                         return $row->Time;
1514                                 }
1515                         }
1516                 }
1517                 return false;
1518         }
1519
1520         /**
1521          * Get status information from SHOW STATUS in an associative array
1522          */
1523         function getStatus() {
1524                 $res = $this->query( 'SHOW STATUS' );
1525                 $status = array();
1526                 while ( $row = $this->fetchObject( $res ) ) {
1527                         $status[$row->Variable_name] = $row->Value;
1528                 }
1529                 return $status;
1530         }
1531 }
1532
1533 /**
1534  * Database abstraction object for mySQL
1535  * Inherit all methods and properties of Database::Database()
1536  *
1537  * @package MediaWiki
1538  * @see Database
1539  */
1540 class DatabaseMysql extends Database {
1541         # Inherit all
1542 }
1543
1544
1545 /**
1546  * Result wrapper for grabbing data queried by someone else
1547  *
1548  * @package MediaWiki
1549  */
1550 class ResultWrapper {
1551         var $db, $result;
1552
1553         /**
1554          * @todo document
1555          */
1556         function ResultWrapper( $database, $result ) {
1557                 $this->db =& $database;
1558                 $this->result =& $result;
1559         }
1560
1561         /**
1562          * @todo document
1563          */
1564         function numRows() {
1565                 return $this->db->numRows( $this->result );
1566         }
1567
1568         /**
1569          * @todo document
1570          */
1571         function fetchObject() {
1572                 return $this->db->fetchObject( $this->result );
1573         }
1574
1575         /**
1576          * @todo document
1577          */
1578         function &fetchRow() {
1579                 return $this->db->fetchRow( $this->result );
1580         }
1581
1582         /**
1583          * @todo document
1584          */
1585         function free() {
1586                 $this->db->freeResult( $this->result );
1587                 unset( $this->result );
1588                 unset( $this->db );
1589         }
1590
1591         function seek( $row ) {
1592                 $this->db->dataSeek( $this->result, $row );
1593         }
1594 }
1595
1596 #------------------------------------------------------------------------------
1597 # Global functions
1598 #------------------------------------------------------------------------------
1599
1600 /**
1601  * Standard fail function, called by default when a connection cannot be
1602  * established.
1603  * Displays the file cache if possible
1604  */
1605 function wfEmergencyAbort( &$conn, $error ) {
1606         global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgOutputEncoding;
1607         global $wgSitename, $wgServer;
1608
1609         # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
1610         # Hard coding strings instead.
1611
1612         $noconnect = 'Sorry! The wiki is experiencing some technical difficulties, and cannot contact the database server. <br />
1613 $1';
1614         $mainpage = 'Main Page';
1615         $searchdisabled = <<<EOT
1616 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
1617 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
1618 EOT;
1619
1620         $googlesearch = "
1621 <!-- SiteSearch Google -->
1622 <FORM method=GET action=\"http://www.google.com/search\">
1623 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
1624 <A HREF=\"http://www.google.com/\">
1625 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
1626 border=\"0\" ALT=\"Google\"></A>
1627 </td>
1628 <td>
1629 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
1630 <INPUT type=submit name=btnG VALUE=\"Google Search\">
1631 <font size=-1>
1632 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
1633 <input type='hidden' name='ie' value='$2'>
1634 <input type='hidden' name='oe' value='$2'>
1635 </font>
1636 </td></tr></TABLE>
1637 </FORM>
1638 <!-- SiteSearch Google -->";
1639         $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
1640
1641
1642         if( !headers_sent() ) {
1643                 header( 'HTTP/1.0 500 Internal Server Error' );
1644                 header( 'Content-type: text/html; charset='.$wgOutputEncoding );
1645                 /* Don't cache error pages!  They cause no end of trouble... */
1646                 header( 'Cache-control: none' );
1647                 header( 'Pragma: nocache' );
1648         }
1649         $msg = wfGetSiteNotice();
1650         if($msg == '') {
1651                 $msg = str_replace( '$1', $error, $noconnect );
1652         }
1653         $text = $msg;
1654
1655         if($wgUseFileCache) {
1656                 if($wgTitle) {
1657                         $t =& $wgTitle;
1658                 } else {
1659                         if($title) {
1660                                 $t = Title::newFromURL( $title );
1661                         } elseif (@/**/$_REQUEST['search']) {
1662                                 $search = $_REQUEST['search'];
1663                                 echo $searchdisabled;
1664                                 echo str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
1665                                   $wgInputEncoding ), $googlesearch );
1666                                 wfErrorExit();
1667                         } else {
1668                                 $t = Title::newFromText( $mainpage );
1669                         }
1670                 }
1671
1672                 $cache = new CacheManager( $t );
1673                 if( $cache->isFileCached() ) {
1674                         $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
1675                                 $cachederror . "</b></p>\n";
1676
1677                         $tag = '<div id="article">';
1678                         $text = str_replace(
1679                                 $tag,
1680                                 $tag . $msg,
1681                                 $cache->fetchPageText() );
1682                 }
1683         }
1684
1685         echo $text;
1686         wfErrorExit();
1687 }
1688
1689 ?>