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 /** See Database::makeList() */
   9 define( 'LIST_COMMA', 0 );
  10 define( 'LIST_AND', 1 );
  11 define( 'LIST_SET', 2 );
  12 define( 'LIST_NAMES', 3);
  13 define( 'LIST_OR', 4);
  14
  15 /** Number of times to re-try an operation in case of deadlock */
  16 define( 'DEADLOCK_TRIES', 4 );
  17 /** Minimum time to wait before retry, in microseconds */
  18 define( 'DEADLOCK_DELAY_MIN', 500000 );
  19 /** Maximum time to wait before retry */
  20 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  21
  22 class DBObject {
  23         var $mData;
  24
  25         function DBObject($data) {
  26                 $this->mData = $data;
  27         }
  28
  29         function isLOB() {
  30                 return false;
  31         }
  32
  33         function data() {
  34                 return $this->mData;
  35         }
  36 };
  37
  38 /**
  39  * Database abstraction object
  40  * @package MediaWiki
  41  */
  42 class Database {
  43
  44 #------------------------------------------------------------------------------
  45 # Variables
  46 #------------------------------------------------------------------------------
  47         /**#@+
  48          * @private
  49          */
  50         var $mLastQuery = '';
  51
  52         var $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  53         var $mOut, $mOpened = false;
  54
  55         var $mFailFunction;
  56         var $mTablePrefix;
  57         var $mFlags;
  58         var $mTrxLevel = 0;
  59         var $mErrorCount = 0;
  60         var $mLBInfo = array();
  61         /**#@-*/
  62
  63 #------------------------------------------------------------------------------
  64 # Accessors
  65 #------------------------------------------------------------------------------
  66         # These optionally set a variable and return the previous state
  67
  68         /**
  69          * Fail function, takes a Database as a parameter
  70          * Set to false for default, 1 for ignore errors
  71          */
  72         function failFunction( $function = NULL ) {
  73                 return wfSetVar( $this->mFailFunction, $function );
  74         }
  75
  76         /**
  77          * Output page, used for reporting errors
  78          * FALSE means discard output
  79          */
  80         function &setOutputPage( &$out ) {
  81                 $this->mOut =& $out;
  82         }
  83
  84         /**
  85          * Boolean, controls output of large amounts of debug information
  86          */
  87         function debug( $debug = NULL ) {
  88                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  89         }
  90
  91         /**
  92          * Turns buffering of SQL result sets on (true) or off (false).
  93          * Default is "on" and it should not be changed without good reasons.
  94          */
  95         function bufferResults( $buffer = NULL ) {
  96                 if ( is_null( $buffer ) ) {
  97                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  98                 } else {
  99                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 100                 }
 101         }
 102
 103         /**
 104          * Turns on (false) or off (true) the automatic generation and sending
 105          * of a "we're sorry, but there has been a database error" page on
 106          * database errors. Default is on (false). When turned off, the
 107          * code should use wfLastErrno() and wfLastError() to handle the
 108          * situation as appropriate.
 109          */
 110         function ignoreErrors( $ignoreErrors = NULL ) {
 111                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 112         }
 113
 114         /**
 115          * The current depth of nested transactions
 116          * @param $level Integer: , default NULL.
 117          */
 118         function trxLevel( $level = NULL ) {
 119                 return wfSetVar( $this->mTrxLevel, $level );
 120         }
 121
 122         /**
 123          * Number of errors logged, only useful when errors are ignored
 124          */
 125         function errorCount( $count = NULL ) {
 126                 return wfSetVar( $this->mErrorCount, $count );
 127         }
 128
 129         /**
 130          * Properties passed down from the server info array of the load balancer
 131          */
 132         function getLBInfo( $name = NULL ) {
 133                 if ( is_null( $name ) ) {
 134                         return $this->mLBInfo;
 135                 } else {
 136                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 137                                 return $this->mLBInfo[$name];
 138                         } else {
 139                                 return NULL;
 140                         }
 141                 }
 142         }
 143
 144         function setLBInfo( $name, $value = NULL ) {
 145                 if ( is_null( $value ) ) {
 146                         $this->mLBInfo = $name;
 147                 } else {
 148                         $this->mLBInfo[$name] = $value;
 149                 }
 150         }
 151
 152         /**#@+
 153          * Get function
 154          */
 155         function lastQuery() { return $this->mLastQuery; }
 156         function isOpen() { return $this->mOpened; }
 157         /**#@-*/
 158
 159         function setFlag( $flag ) {
 160                 $this->mFlags |= $flag;
 161         }
 162
 163         function clearFlag( $flag ) {
 164                 $this->mFlags &= ~$flag;
 165         }
 166
 167         function getFlag( $flag ) {
 168                 return !!($this->mFlags & $flag);
 169         }
 170
 171 #------------------------------------------------------------------------------
 172 # Other functions
 173 #------------------------------------------------------------------------------
 174
 175         /**@{{
 176          * @param string $server database server host
 177          * @param string $user database user name
 178          * @param string $password database user password
 179          * @param string $dbname database name
 180          */
 181
 182         /**
 183          * @param failFunction
 184          * @param $flags
 185          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 186          */
 187         function Database( $server = false, $user = false, $password = false, $dbName = false,
 188                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 189
 190                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 191                 # Can't get a reference if it hasn't been set yet
 192                 if ( !isset( $wgOut ) ) {
 193                         $wgOut = NULL;
 194                 }
 195                 $this->mOut =& $wgOut;
 196
 197                 $this->mFailFunction = $failFunction;
 198                 $this->mFlags = $flags;
 199
 200                 if ( $this->mFlags & DBO_DEFAULT ) {
 201                         if ( $wgCommandLineMode ) {
 202                                 $this->mFlags &= ~DBO_TRX;
 203                         } else {
 204                                 $this->mFlags |= DBO_TRX;
 205                         }
 206                 }
 207
 208                 /*
 209                 // Faster read-only access
 210                 if ( wfReadOnly() ) {
 211                         $this->mFlags |= DBO_PERSISTENT;
 212                         $this->mFlags &= ~DBO_TRX;
 213                 }*/
 214
 215                 /** Get the default table prefix*/
 216                 if ( $tablePrefix == 'get from global' ) {
 217                         $this->mTablePrefix = $wgDBprefix;
 218                 } else {
 219                         $this->mTablePrefix = $tablePrefix;
 220                 }
 221
 222                 if ( $server ) {
 223                         $this->open( $server, $user, $password, $dbName );
 224                 }
 225         }
 226
 227         /**
 228          * @static
 229          * @param failFunction
 230          * @param $flags
 231          */
 232         function newFromParams( $server, $user, $password, $dbName,
 233                 $failFunction = false, $flags = 0 )
 234         {
 235                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 236         }
 237
 238         /**
 239          * Usually aborts on failure
 240          * If the failFunction is set to a non-zero integer, returns success
 241          */
 242         function open( $server, $user, $password, $dbName ) {
 243                 global $wguname;
 244
 245                 # Test for missing mysql.so
 246                 # First try to load it
 247                 if (!@extension_loaded('mysql')) {
 248                         @dl('mysql.so');
 249                 }
 250
 251                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 252                 if ( !function_exists( 'mysql_connect' ) ) {
 253                         wfDie( "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 254                 }
 255
 256                 $this->close();
 257                 $this->mServer = $server;
 258                 $this->mUser = $user;
 259                 $this->mPassword = $password;
 260                 $this->mDBname = $dbName;
 261
 262                 $success = false;
 263
 264                 if ( $this->mFlags & DBO_PERSISTENT ) {
 265                         @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 266                 } else {
 267                         # Create a new connection...
 268                         @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 269                 }
 270
 271                 if ( $dbName != '' ) {
 272                         if ( $this->mConn !== false ) {
 273                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 274                                 if ( !$success ) {
 275                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 276                                                 "from client host {$wguname['nodename']}\n";
 277                                         wfDebug( $error );
 278                                 }
 279                         } else {
 280                                 wfDebug( "DB connection error\n" );
 281                                 wfDebug( "Server: $server, User: $user, Password: " .
 282                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 283                                 $success = false;
 284                         }
 285                 } else {
 286                         # Delay USE query
 287                         $success = (bool)$this->mConn;
 288                 }
 289
 290                 if ( !$success ) {
 291                         $this->reportConnectionError();
 292                 }
 293
 294                 global $wgDBmysql5;
 295                 if( $wgDBmysql5 ) {
 296                         // Tell the server we're communicating with it in UTF-8.
 297                         // This may engage various charset conversions.
 298                         $this->query( 'SET NAMES utf8' );
 299                 }
 300
 301                 $this->mOpened = $success;
 302                 return $success;
 303         }
 304         /**@}}*/
 305
 306         /**
 307          * Closes a database connection.
 308          * if it is open : commits any open transactions
 309          *
 310          * @return bool operation success. true if already closed.
 311          */
 312         function close()
 313         {
 314                 $this->mOpened = false;
 315                 if ( $this->mConn ) {
 316                         if ( $this->trxLevel() ) {
 317                                 $this->immediateCommit();
 318                         }
 319                         return mysql_close( $this->mConn );
 320                 } else {
 321                         return true;
 322                 }
 323         }
 324
 325         /**
 326          * @private
 327          * @param string $error fallback error message, used if none is given by MySQL
 328          */
 329         function reportConnectionError( $error = 'Unknown error' ) {
 330                 $myError = $this->lastError();
 331                 if ( $myError ) {
 332                         $error = $myError;
 333                 }
 334
 335                 if ( $this->mFailFunction ) {
 336                         if ( !is_int( $this->mFailFunction ) ) {
 337                                 $ff = $this->mFailFunction;
 338                                 $ff( $this, $error );
 339                         }
 340                 } else {
 341                         wfEmergencyAbort( $this, $error );
 342                 }
 343         }
 344
 345         /**
 346          * Usually aborts on failure
 347          * If errors are explicitly ignored, returns success
 348          */
 349         function query( $sql, $fname = '', $tempIgnore = false ) {
 350                 global $wgProfiling;
 351
 352                 if ( $wgProfiling ) {
 353                         # generalizeSQL will probably cut down the query to reasonable
 354                         # logging size most of the time. The substr is really just a sanity check.
 355
 356                         # Who's been wasting my precious column space? -- TS
 357                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 358
 359                         if ( is_null( $this->getLBInfo( 'master' ) ) ) {
 360                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 361                                 $totalProf = 'Database::query';
 362                         } else {
 363                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 364                                 $totalProf = 'Database::query-master';
 365                         }
 366                         wfProfileIn( $totalProf );
 367                         wfProfileIn( $queryProf );
 368                 }
 369
 370                 $this->mLastQuery = $sql;
 371
 372                 # Add a comment for easy SHOW PROCESSLIST interpretation
 373                 if ( $fname ) {
 374                         $commentedSql = preg_replace("/\s/", " /* $fname */ ", $sql, 1);
 375                 } else {
 376                         $commentedSql = $sql;
 377                 }
 378
 379                 # If DBO_TRX is set, start a transaction
 380                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() && $sql != 'BEGIN' ) {
 381                         $this->begin();
 382                 }
 383
 384                 if ( $this->debug() ) {
 385                         $sqlx = substr( $commentedSql, 0, 500 );
 386                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 387                         wfDebug( "SQL: $sqlx\n" );
 388                 }
 389
 390                 # Do the query and handle errors
 391                 $ret = $this->doQuery( $commentedSql );
 392
 393                 # Try reconnecting if the connection was lost
 394                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 395                         # Transaction is gone, like it or not
 396                         $this->mTrxLevel = 0;
 397                         wfDebug( "Connection lost, reconnecting...\n" );
 398                         if ( $this->ping() ) {
 399                                 wfDebug( "Reconnected\n" );
 400                                 $ret = $this->doQuery( $commentedSql );
 401                         } else {
 402                                 wfDebug( "Failed\n" );
 403                         }
 404                 }
 405
 406                 if ( false === $ret ) {
 407                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 408                 }
 409
 410                 if ( $wgProfiling ) {
 411                         wfProfileOut( $queryProf );
 412                         wfProfileOut( $totalProf );
 413                 }
 414                 return $ret;
 415         }
 416
 417         /**
 418          * The DBMS-dependent part of query()
 419          * @param string $sql SQL query.
 420          */
 421         function doQuery( $sql ) {
 422                 if( $this->bufferResults() ) {
 423                         $ret = mysql_query( $sql, $this->mConn );
 424                 } else {
 425                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 426                 }
 427                 return $ret;
 428         }
 429
 430         /**
 431          * @param $error
 432          * @param $errno
 433          * @param $sql
 434          * @param string $fname
 435          * @param bool $tempIgnore
 436          */
 437         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 438                 global $wgCommandLineMode, $wgFullyInitialised, $wgColorErrors;
 439                 # Ignore errors during error handling to avoid infinite recursion
 440                 $ignore = $this->ignoreErrors( true );
 441                 ++$this->mErrorCount;
 442
 443                 if( $ignore || $tempIgnore ) {
 444                         wfDebug("SQL ERROR (ignored): $error\n");
 445                 } else {
 446                         $sql1line = str_replace( "\n", "\\n", $sql );
 447                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 448                         wfDebug("SQL ERROR: " . $error . "\n");
 449                         if ( $wgCommandLineMode || !$this->mOut || empty( $wgFullyInitialised ) ) {
 450                                 $message = "A database error has occurred\n" .
 451                                   "Query: $sql\n" .
 452                                   "Function: $fname\n" .
 453                                   "Error: $errno $error\n";
 454                                 if ( !$wgCommandLineMode ) {
 455                                         $message = nl2br( $message );
 456                                 }
 457                                 if( $wgCommandLineMode && $wgColorErrors && !wfIsWindows() && posix_isatty(1) ) {
 458                                         $color = 31; // bright red!
 459                                         $message = "\x1b[1;{$color}m{$message}\x1b[0m";
 460                                 }
 461                                 wfDebugDieBacktrace( $message );
 462                         } else {
 463                                 // this calls wfAbruptExit()
 464                                 $this->mOut->databaseError( $fname, $sql, $error, $errno );
 465                         }
 466                 }
 467                 $this->ignoreErrors( $ignore );
 468         }
 469
 470
 471         /**
 472          * Intended to be compatible with the PEAR::DB wrapper functions.
 473          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 474          *
 475          * ? = scalar value, quoted as necessary
 476          * ! = raw SQL bit (a function for instance)
 477          * & = filename; reads the file and inserts as a blob
 478          *     (we don't use this though...)
 479          */
 480         function prepare( $sql, $func = 'Database::prepare' ) {
 481                 /* MySQL doesn't support prepared statements (yet), so just
 482                    pack up the query for reference. We'll manually replace
 483                    the bits later. */
 484                 return array( 'query' => $sql, 'func' => $func );
 485         }
 486
 487         function freePrepared( $prepared ) {
 488                 /* No-op for MySQL */
 489         }
 490
 491         /**
 492          * Execute a prepared query with the various arguments
 493          * @param string $prepared the prepared sql
 494          * @param mixed $args Either an array here, or put scalars as varargs
 495          */
 496         function execute( $prepared, $args = null ) {
 497                 if( !is_array( $args ) ) {
 498                         # Pull the var args
 499                         $args = func_get_args();
 500                         array_shift( $args );
 501                 }
 502                 $sql = $this->fillPrepared( $prepared['query'], $args );
 503                 return $this->query( $sql, $prepared['func'] );
 504         }
 505
 506         /**
 507          * Prepare & execute an SQL statement, quoting and inserting arguments
 508          * in the appropriate places.
 509          * @param string $query
 510          * @param string $args ...
 511          */
 512         function safeQuery( $query, $args = null ) {
 513                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 514                 if( !is_array( $args ) ) {
 515                         # Pull the var args
 516                         $args = func_get_args();
 517                         array_shift( $args );
 518                 }
 519                 $retval = $this->execute( $prepared, $args );
 520                 $this->freePrepared( $prepared );
 521                 return $retval;
 522         }
 523
 524         /**
 525          * For faking prepared SQL statements on DBs that don't support
 526          * it directly.
 527          * @param string $preparedSql - a 'preparable' SQL statement
 528          * @param array $args - array of arguments to fill it with
 529          * @return string executable SQL
 530          */
 531         function fillPrepared( $preparedQuery, $args ) {
 532                 reset( $args );
 533                 $this->preparedArgs =& $args;
 534                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 535                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 536         }
 537
 538         /**
 539          * preg_callback func for fillPrepared()
 540          * The arguments should be in $this->preparedArgs and must not be touched
 541          * while we're doing this.
 542          *
 543          * @param array $matches
 544          * @return string
 545          * @private
 546          */
 547         function fillPreparedArg( $matches ) {
 548                 switch( $matches[1] ) {
 549                         case '\\?': return '?';
 550                         case '\\!': return '!';
 551                         case '\\&': return '&';
 552                 }
 553                 list( $n, $arg ) = each( $this->preparedArgs );
 554                 switch( $matches[1] ) {
 555                         case '?': return $this->addQuotes( $arg );
 556                         case '!': return $arg;
 557                         case '&':
 558                                 # return $this->addQuotes( file_get_contents( $arg ) );
 559                                 wfDebugDieBacktrace( '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 560                         default:
 561                                 wfDebugDieBacktrace( 'Received invalid match. This should never happen!' );
 562                 }
 563         }
 564
 565         /**#@+
 566          * @param mixed $res A SQL result
 567          */
 568         /**
 569          * Free a result object
 570          */
 571         function freeResult( $res ) {
 572                 if ( !@/**/mysql_free_result( $res ) ) {
 573                         wfDebugDieBacktrace( "Unable to free MySQL result\n" );
 574                 }
 575         }
 576
 577         /**
 578          * Fetch the next row from the given result object, in object form
 579          */
 580         function fetchObject( $res ) {
 581                 @/**/$row = mysql_fetch_object( $res );
 582                 if( mysql_errno() ) {
 583                         wfDebugDieBacktrace( 'Error in fetchObject(): ' . htmlspecialchars( mysql_error() ) );
 584                 }
 585                 return $row;
 586         }
 587
 588         /**
 589          * Fetch the next row from the given result object
 590          * Returns an array
 591          */
 592         function fetchRow( $res ) {
 593                 @/**/$row = mysql_fetch_array( $res );
 594                 if (mysql_errno() ) {
 595                         wfDebugDieBacktrace( 'Error in fetchRow(): ' . htmlspecialchars( mysql_error() ) );
 596                 }
 597                 return $row;
 598         }
 599
 600         /**
 601          * Get the number of rows in a result object
 602          */
 603         function numRows( $res ) {
 604                 @/**/$n = mysql_num_rows( $res );
 605                 if( mysql_errno() ) {
 606                         wfDebugDieBacktrace( 'Error in numRows(): ' . htmlspecialchars( mysql_error() ) );
 607                 }
 608                 return $n;
 609         }
 610
 611         /**
 612          * Get the number of fields in a result object
 613          * See documentation for mysql_num_fields()
 614          */
 615         function numFields( $res ) { return mysql_num_fields( $res ); }
 616
 617         /**
 618          * Get a field name in a result object
 619          * See documentation for mysql_field_name():
 620          * http://www.php.net/mysql_field_name
 621          */
 622         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 623
 624         /**
 625          * Get the inserted value of an auto-increment row
 626          *
 627          * The value inserted should be fetched from nextSequenceValue()
 628          *
 629          * Example:
 630          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 631          * $dbw->insert('page',array('page_id' => $id));
 632          * $id = $dbw->insertId();
 633          */
 634         function insertId() { return mysql_insert_id( $this->mConn ); }
 635
 636         /**
 637          * Change the position of the cursor in a result object
 638          * See mysql_data_seek()
 639          */
 640         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 641
 642         /**
 643          * Get the last error number
 644          * See mysql_errno()
 645          */
 646         function lastErrno() {
 647                 if ( $this->mConn ) {
 648                         return mysql_errno( $this->mConn );
 649                 } else {
 650                         return mysql_errno();
 651                 }
 652         }
 653
 654         /**
 655          * Get a description of the last error
 656          * See mysql_error() for more details
 657          */
 658         function lastError() {
 659                 if ( $this->mConn ) {
 660                         # Even if it's non-zero, it can still be invalid
 661                         wfSuppressWarnings();
 662                         $error = mysql_error( $this->mConn );
 663                         if ( !$error ) {
 664                                 $error = mysql_error();
 665                         }
 666                         wfRestoreWarnings();
 667                 } else {
 668                         $error = mysql_error();
 669                 }
 670                 if( $error ) {
 671                         $error .= ' (' . $this->mServer . ')';
 672                 }
 673                 return $error;
 674         }
 675         /**
 676          * Get the number of rows affected by the last write query
 677          * See mysql_affected_rows() for more details
 678          */
 679         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 680         /**#@-*/ // end of template : @param $result
 681
 682         /**
 683          * Simple UPDATE wrapper
 684          * Usually aborts on failure
 685          * If errors are explicitly ignored, returns success
 686          *
 687          * This function exists for historical reasons, Database::update() has a more standard
 688          * calling convention and feature set
 689          */
 690         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 691         {
 692                 $table = $this->tableName( $table );
 693                 $sql = "UPDATE $table SET $var = '" .
 694                   $this->strencode( $value ) . "' WHERE ($cond)";
 695                 return (bool)$this->query( $sql, $fname );
 696         }
 697
 698         /**
 699          * Simple SELECT wrapper, returns a single field, input must be encoded
 700          * Usually aborts on failure
 701          * If errors are explicitly ignored, returns FALSE on failure
 702          */
 703         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 704                 if ( !is_array( $options ) ) {
 705                         $options = array( $options );
 706                 }
 707                 $options['LIMIT'] = 1;
 708
 709                 $res = $this->select( $table, $var, $cond, $fname, $options );
 710                 if ( $res === false || !$this->numRows( $res ) ) {
 711                         return false;
 712                 }
 713                 $row = $this->fetchRow( $res );
 714                 if ( $row !== false ) {
 715                         $this->freeResult( $res );
 716                         return $row[0];
 717                 } else {
 718                         return false;
 719                 }
 720         }
 721
 722         /**
 723          * Returns an optional USE INDEX clause to go after the table, and a
 724          * string to go at the end of the query
 725          *
 726          * @private
 727          *
 728          * @param array $options an associative array of options to be turned into
 729          *              an SQL query, valid keys are listed in the function.
 730          * @return array
 731          */
 732         function makeSelectOptions( $options ) {
 733                 $tailOpts = '';
 734                 $startOpts = '';
 735
 736                 $noKeyOptions = array();
 737                 foreach ( $options as $key => $option ) {
 738                         if ( is_numeric( $key ) ) {
 739                                 $noKeyOptions[$option] = true;
 740                         }
 741                 }
 742
 743                 if ( isset( $options['GROUP BY'] ) ) $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 744                 if ( isset( $options['ORDER BY'] ) ) $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 745
 746                 if (isset($options['LIMIT'])) {
 747                         $tailOpts .= $this->limitResult('', $options['LIMIT'],
 748                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 749                 }
 750
 751                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $tailOpts .= ' FOR UPDATE';
 752                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $tailOpts .= ' LOCK IN SHARE MODE';
 753                 if ( isset( $noKeyOptions['DISTINCT'] ) && isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 754
 755                 # Various MySQL extensions
 756                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 757                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 758                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 759                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 760                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 761                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 762                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 763
 764                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 765                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 766                 } else {
 767                         $useIndex = '';
 768                 }
 769
 770                 return array( $startOpts, $useIndex, $tailOpts );
 771         }
 772
 773         /**
 774          * SELECT wrapper
 775          */
 776         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
 777         {
 778                 if( is_array( $vars ) ) {
 779                         $vars = implode( ',', $vars );
 780                 }
 781                 if( !is_array( $options ) ) {
 782                         $options = array( $options );
 783                 }
 784                 if( is_array( $table ) ) {
 785                         if ( @is_array( $options['USE INDEX'] ) )
 786                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
 787                         else
 788                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 789                 } elseif ($table!='') {
 790                         $from = ' FROM ' . $this->tableName( $table );
 791                 } else {
 792                         $from = '';
 793                 }
 794
 795                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $options );
 796
 797                 if( !empty( $conds ) ) {
 798                         if ( is_array( $conds ) ) {
 799                                 $conds = $this->makeList( $conds, LIST_AND );
 800                         }
 801                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $tailOpts";
 802                 } else {
 803                         $sql = "SELECT $startOpts $vars $from $useIndex $tailOpts";
 804                 }
 805
 806                 return $this->query( $sql, $fname );
 807         }
 808
 809         /**
 810          * Single row SELECT wrapper
 811          * Aborts or returns FALSE on error
 812          *
 813          * $vars: the selected variables
 814          * $conds: a condition map, terms are ANDed together.
 815          *   Items with numeric keys are taken to be literal conditions
 816          * Takes an array of selected variables, and a condition map, which is ANDed
 817          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 818          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 819          * $obj- >page_id is the ID of the Astronomy article
 820          *
 821          * @todo migrate documentation to phpdocumentor format
 822          */
 823         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
 824                 $options['LIMIT'] = 1;
 825                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 826                 if ( $res === false )
 827                         return false;
 828                 if ( !$this->numRows($res) ) {
 829                         $this->freeResult($res);
 830                         return false;
 831                 }
 832                 $obj = $this->fetchObject( $res );
 833                 $this->freeResult( $res );
 834                 return $obj;
 835
 836         }
 837
 838         /**
 839          * Removes most variables from an SQL query and replaces them with X or N for numbers.
 840          * It's only slightly flawed. Don't use for anything important.
 841          *
 842          * @param string $sql A SQL Query
 843          * @static
 844          */
 845         function generalizeSQL( $sql ) {
 846                 # This does the same as the regexp below would do, but in such a way
 847                 # as to avoid crashing php on some large strings.
 848                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
 849
 850                 $sql = str_replace ( "\\\\", '', $sql);
 851                 $sql = str_replace ( "\\'", '', $sql);
 852                 $sql = str_replace ( "\\\"", '', $sql);
 853                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
 854                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
 855
 856                 # All newlines, tabs, etc replaced by single space
 857                 $sql = preg_replace ( "/\s+/", ' ', $sql);
 858
 859                 # All numbers => N
 860                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
 861
 862                 return $sql;
 863         }
 864
 865         /**
 866          * Determines whether a field exists in a table
 867          * Usually aborts on failure
 868          * If errors are explicitly ignored, returns NULL on failure
 869          */
 870         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
 871                 $table = $this->tableName( $table );
 872                 $res = $this->query( 'DESCRIBE '.$table, $fname );
 873                 if ( !$res ) {
 874                         return NULL;
 875                 }
 876
 877                 $found = false;
 878
 879                 while ( $row = $this->fetchObject( $res ) ) {
 880                         if ( $row->Field == $field ) {
 881                                 $found = true;
 882                                 break;
 883                         }
 884                 }
 885                 return $found;
 886         }
 887
 888         /**
 889          * Determines whether an index exists
 890          * Usually aborts on failure
 891          * If errors are explicitly ignored, returns NULL on failure
 892          */
 893         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
 894                 $info = $this->indexInfo( $table, $index, $fname );
 895                 if ( is_null( $info ) ) {
 896                         return NULL;
 897                 } else {
 898                         return $info !== false;
 899                 }
 900         }
 901
 902
 903         /**
 904          * Get information about an index into an object
 905          * Returns false if the index does not exist
 906          */
 907         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
 908                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 909                 # SHOW INDEX should work for 3.x and up:
 910                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 911                 $table = $this->tableName( $table );
 912                 $sql = 'SHOW INDEX FROM '.$table;
 913                 $res = $this->query( $sql, $fname );
 914                 if ( !$res ) {
 915                         return NULL;
 916                 }
 917
 918                 while ( $row = $this->fetchObject( $res ) ) {
 919                         if ( $row->Key_name == $index ) {
 920                                 return $row;
 921                         }
 922                 }
 923                 return false;
 924         }
 925
 926         /**
 927          * Query whether a given table exists
 928          */
 929         function tableExists( $table ) {
 930                 $table = $this->tableName( $table );
 931                 $old = $this->ignoreErrors( true );
 932                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
 933                 $this->ignoreErrors( $old );
 934                 if( $res ) {
 935                         $this->freeResult( $res );
 936                         return true;
 937                 } else {
 938                         return false;
 939                 }
 940         }
 941
 942         /**
 943          * mysql_fetch_field() wrapper
 944          * Returns false if the field doesn't exist
 945          *
 946          * @param $table
 947          * @param $field
 948          */
 949         function fieldInfo( $table, $field ) {
 950                 $table = $this->tableName( $table );
 951                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
 952                 $n = mysql_num_fields( $res );
 953                 for( $i = 0; $i < $n; $i++ ) {
 954                         $meta = mysql_fetch_field( $res, $i );
 955                         if( $field == $meta->name ) {
 956                                 return $meta;
 957                         }
 958                 }
 959                 return false;
 960         }
 961
 962         /**
 963          * mysql_field_type() wrapper
 964          */
 965         function fieldType( $res, $index ) {
 966                 return mysql_field_type( $res, $index );
 967         }
 968
 969         /**
 970          * Determines if a given index is unique
 971          */
 972         function indexUnique( $table, $index ) {
 973                 $indexInfo = $this->indexInfo( $table, $index );
 974                 if ( !$indexInfo ) {
 975                         return NULL;
 976                 }
 977                 return !$indexInfo->Non_unique;
 978         }
 979
 980         /**
 981          * INSERT wrapper, inserts an array into a table
 982          *
 983          * $a may be a single associative array, or an array of these with numeric keys, for
 984          * multi-row insert.
 985          *
 986          * Usually aborts on failure
 987          * If errors are explicitly ignored, returns success
 988          */
 989         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
 990                 # No rows to insert, easy just return now
 991                 if ( !count( $a ) ) {
 992                         return true;
 993                 }
 994
 995                 $table = $this->tableName( $table );
 996                 if ( !is_array( $options ) ) {
 997                         $options = array( $options );
 998                 }
 999                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1000                         $multi = true;
1001                         $keys = array_keys( $a[0] );
1002                 } else {
1003                         $multi = false;
1004                         $keys = array_keys( $a );
1005                 }
1006
1007                 $sql = 'INSERT ' . implode( ' ', $options ) .
1008                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1009
1010                 if ( $multi ) {
1011                         $first = true;
1012                         foreach ( $a as $row ) {
1013                                 if ( $first ) {
1014                                         $first = false;
1015                                 } else {
1016                                         $sql .= ',';
1017                                 }
1018                                 $sql .= '(' . $this->makeList( $row ) . ')';
1019                         }
1020                 } else {
1021                         $sql .= '(' . $this->makeList( $a ) . ')';
1022                 }
1023                 return (bool)$this->query( $sql, $fname );
1024         }
1025
1026         /**
1027          * Make UPDATE options for the Database::update function
1028          *
1029          * @private
1030          * @param array $options The options passed to Database::update
1031          * @return string
1032          */
1033         function makeUpdateOptions( $options ) {
1034                 if( !is_array( $options ) ) {
1035                         $options = array( $options );
1036                 }
1037                 $opts = array();
1038                 if ( in_array( 'LOW_PRIORITY', $options ) )
1039                         $opts[] = $this->lowPriorityOption();
1040                 if ( in_array( 'IGNORE', $options ) )
1041                         $opts[] = 'IGNORE';
1042                 return implode(' ', $opts);
1043         }
1044
1045         /**
1046          * UPDATE wrapper, takes a condition array and a SET array
1047          *
1048          * @param string $table  The table to UPDATE
1049          * @param array  $values An array of values to SET
1050          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1051          * @param string $fname  The Class::Function calling this function
1052          *                       (for the log)
1053          * @param array  $options An array of UPDATE options, can be one or
1054          *                        more of IGNORE, LOW_PRIORITY
1055          */
1056         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1057                 $table = $this->tableName( $table );
1058                 $opts = $this->makeUpdateOptions( $options );
1059                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1060                 if ( $conds != '*' ) {
1061                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1062                 }
1063                 $this->query( $sql, $fname );
1064         }
1065
1066         /**
1067          * Makes a wfStrencoded list from an array
1068          * $mode:
1069          *        LIST_COMMA         - comma separated, no field names
1070          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1071          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1072          *        LIST_SET           - comma separated with field names, like a SET clause
1073          *        LIST_NAMES         - comma separated field names
1074          */
1075         function makeList( $a, $mode = LIST_COMMA ) {
1076                 if ( !is_array( $a ) ) {
1077                         wfDebugDieBacktrace( 'Database::makeList called with incorrect parameters' );
1078                 }
1079
1080                 $first = true;
1081                 $list = '';
1082                 foreach ( $a as $field => $value ) {
1083                         if ( !$first ) {
1084                                 if ( $mode == LIST_AND ) {
1085                                         $list .= ' AND ';
1086                                 } elseif($mode == LIST_OR) {
1087                                         $list .= ' OR ';
1088                                 } else {
1089                                         $list .= ',';
1090                                 }
1091                         } else {
1092                                 $first = false;
1093                         }
1094                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1095                                 $list .= "($value)";
1096                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array ($value) ) {
1097                                 $list .= $field." IN (".$this->makeList($value).") ";
1098                         } else {
1099                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1100                                         $list .= "$field = ";
1101                                 }
1102                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1103                         }
1104                 }
1105                 return $list;
1106         }
1107
1108         /**
1109          * Change the current database
1110          */
1111         function selectDB( $db ) {
1112                 $this->mDBname = $db;
1113                 return mysql_select_db( $db, $this->mConn );
1114         }
1115
1116         /**
1117          * Format a table name ready for use in constructing an SQL query
1118          *
1119          * This does two important things: it quotes table names which as necessary,
1120          * and it adds a table prefix if there is one.
1121          *
1122          * All functions of this object which require a table name call this function
1123          * themselves. Pass the canonical name to such functions. This is only needed
1124          * when calling query() directly.
1125          *
1126          * @param string $name database table name
1127          */
1128         function tableName( $name ) {
1129                 global $wgSharedDB;
1130                 # Skip quoted literals
1131                 if ( $name{0} != '`' ) {
1132                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1133                                 $name = "{$this->mTablePrefix}$name";
1134                         }
1135                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1136                                 $name = "`$wgSharedDB`.`$name`";
1137                         } else {
1138                                 # Standard quoting
1139                                 $name = "`$name`";
1140                         }
1141                 }
1142                 return $name;
1143         }
1144
1145         /**
1146          * Fetch a number of table names into an array
1147          * This is handy when you need to construct SQL for joins
1148          *
1149          * Example:
1150          * extract($dbr->tableNames('user','watchlist'));
1151          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1152          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1153          */
1154         function tableNames() {
1155                 $inArray = func_get_args();
1156                 $retVal = array();
1157                 foreach ( $inArray as $name ) {
1158                         $retVal[$name] = $this->tableName( $name );
1159                 }
1160                 return $retVal;
1161         }
1162
1163         /**
1164          * @private
1165          */
1166         function tableNamesWithUseIndex( $tables, $use_index ) {
1167                 $ret = array();
1168
1169                 foreach ( $tables as $table )
1170                         if ( @$use_index[$table] !== null )
1171                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1172                         else
1173                                 $ret[] = $this->tableName( $table );
1174
1175                 return implode( ',', $ret );
1176         }
1177
1178         /**
1179          * Wrapper for addslashes()
1180          * @param string $s String to be slashed.
1181          * @return string slashed string.
1182          */
1183         function strencode( $s ) {
1184                 return addslashes( $s );
1185         }
1186
1187         /**
1188          * If it's a string, adds quotes and backslashes
1189          * Otherwise returns as-is
1190          */
1191         function addQuotes( $s ) {
1192                 if ( is_null( $s ) ) {
1193                         return 'NULL';
1194                 } else {
1195                         # This will also quote numeric values. This should be harmless,
1196                         # and protects against weird problems that occur when they really
1197                         # _are_ strings such as article titles and string->number->string
1198                         # conversion is not 1:1.
1199                         return "'" . $this->strencode( $s ) . "'";
1200                 }
1201         }
1202
1203         /**
1204          * Escape string for safe LIKE usage
1205          */
1206         function escapeLike( $s ) {
1207                 $s=$this->strencode( $s );
1208                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1209                 return $s;
1210         }
1211
1212         /**
1213          * Returns an appropriately quoted sequence value for inserting a new row.
1214          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1215          * subclass will return an integer, and save the value for insertId()
1216          */
1217         function nextSequenceValue( $seqName ) {
1218                 return NULL;
1219         }
1220
1221         /**
1222          * USE INDEX clause
1223          * PostgreSQL doesn't have them and returns ""
1224          */
1225         function useIndexClause( $index ) {
1226                 return "FORCE INDEX ($index)";
1227         }
1228
1229         /**
1230          * REPLACE query wrapper
1231          * PostgreSQL simulates this with a DELETE followed by INSERT
1232          * $row is the row to insert, an associative array
1233          * $uniqueIndexes is an array of indexes. Each element may be either a
1234          * field name or an array of field names
1235          *
1236          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1237          * However if you do this, you run the risk of encountering errors which wouldn't have
1238          * occurred in MySQL
1239          *
1240          * @todo migrate comment to phodocumentor format
1241          */
1242         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1243                 $table = $this->tableName( $table );
1244
1245                 # Single row case
1246                 if ( !is_array( reset( $rows ) ) ) {
1247                         $rows = array( $rows );
1248                 }
1249
1250                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1251                 $first = true;
1252                 foreach ( $rows as $row ) {
1253                         if ( $first ) {
1254                                 $first = false;
1255                         } else {
1256                                 $sql .= ',';
1257                         }
1258                         $sql .= '(' . $this->makeList( $row ) . ')';
1259                 }
1260                 return $this->query( $sql, $fname );
1261         }
1262
1263         /**
1264          * DELETE where the condition is a join
1265          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1266          *
1267          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1268          * join condition matches, set $conds='*'
1269          *
1270          * DO NOT put the join condition in $conds
1271          *
1272          * @param string $delTable The table to delete from.
1273          * @param string $joinTable The other table.
1274          * @param string $delVar The variable to join on, in the first table.
1275          * @param string $joinVar The variable to join on, in the second table.
1276          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1277          */
1278         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1279                 if ( !$conds ) {
1280                         wfDebugDieBacktrace( 'Database::deleteJoin() called with empty $conds' );
1281                 }
1282
1283                 $delTable = $this->tableName( $delTable );
1284                 $joinTable = $this->tableName( $joinTable );
1285                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1286                 if ( $conds != '*' ) {
1287                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1288                 }
1289
1290                 return $this->query( $sql, $fname );
1291         }
1292
1293         /**
1294          * Returns the size of a text field, or -1 for "unlimited"
1295          */
1296         function textFieldSize( $table, $field ) {
1297                 $table = $this->tableName( $table );
1298                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1299                 $res = $this->query( $sql, 'Database::textFieldSize' );
1300                 $row = $this->fetchObject( $res );
1301                 $this->freeResult( $res );
1302
1303                 if ( preg_match( "/\((.*)\)/", $row->Type, $m ) ) {
1304                         $size = $m[1];
1305                 } else {
1306                         $size = -1;
1307                 }
1308                 return $size;
1309         }
1310
1311         /**
1312          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1313          */
1314         function lowPriorityOption() {
1315                 return 'LOW_PRIORITY';
1316         }
1317
1318         /**
1319          * DELETE query wrapper
1320          *
1321          * Use $conds == "*" to delete all rows
1322          */
1323         function delete( $table, $conds, $fname = 'Database::delete' ) {
1324                 if ( !$conds ) {
1325                         wfDebugDieBacktrace( 'Database::delete() called with no conditions' );
1326                 }
1327                 $table = $this->tableName( $table );
1328                 $sql = "DELETE FROM $table";
1329                 if ( $conds != '*' ) {
1330                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1331                 }
1332                 return $this->query( $sql, $fname );
1333         }
1334
1335         /**
1336          * INSERT SELECT wrapper
1337          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1338          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1339          * $conds may be "*" to copy the whole table
1340          * srcTable may be an array of tables.
1341          */
1342         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1343                 $insertOptions = array(), $selectOptions = array() )
1344         {
1345                 $destTable = $this->tableName( $destTable );
1346                 if ( is_array( $insertOptions ) ) {
1347                         $insertOptions = implode( ' ', $insertOptions );
1348                 }
1349                 if( !is_array( $selectOptions ) ) {
1350                         $selectOptions = array( $selectOptions );
1351                 }
1352                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1353                 if( is_array( $srcTable ) ) {
1354                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1355                 } else {
1356                         $srcTable = $this->tableName( $srcTable );
1357                 }
1358                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1359                         " SELECT $startOpts " . implode( ',', $varMap ) .
1360                         " FROM $srcTable $useIndex ";
1361                 if ( $conds != '*' ) {
1362                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1363                 }
1364                 $sql .= " $tailOpts";
1365                 return $this->query( $sql, $fname );
1366         }
1367
1368         /**
1369          * Construct a LIMIT query with optional offset
1370          * This is used for query pages
1371          * $sql string SQL query we will append the limit too
1372          * $limit integer the SQL limit
1373          * $offset integer the SQL offset (default false)
1374          */
1375         function limitResult($sql, $limit, $offset=false) {
1376                 if( !is_numeric($limit) ) {
1377                         wfDie( "Invalid non-numeric limit passed to limitResult()\n" );
1378                 }
1379                 return " $sql LIMIT "
1380                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1381                                 . "{$limit} ";
1382         }
1383         function limitResultForUpdate($sql, $num) {
1384                 return $this->limitResult($sql, $num, 0);
1385         }
1386
1387         /**
1388          * Returns an SQL expression for a simple conditional.
1389          * Uses IF on MySQL.
1390          *
1391          * @param string $cond SQL expression which will result in a boolean value
1392          * @param string $trueVal SQL expression to return if true
1393          * @param string $falseVal SQL expression to return if false
1394          * @return string SQL fragment
1395          */
1396         function conditional( $cond, $trueVal, $falseVal ) {
1397                 return " IF($cond, $trueVal, $falseVal) ";
1398         }
1399
1400         /**
1401          * Determines if the last failure was due to a deadlock
1402          */
1403         function wasDeadlock() {
1404                 return $this->lastErrno() == 1213;
1405         }
1406
1407         /**
1408          * Perform a deadlock-prone transaction.
1409          *
1410          * This function invokes a callback function to perform a set of write
1411          * queries. If a deadlock occurs during the processing, the transaction
1412          * will be rolled back and the callback function will be called again.
1413          *
1414          * Usage:
1415          *   $dbw->deadlockLoop( callback, ... );
1416          *
1417          * Extra arguments are passed through to the specified callback function.
1418          *
1419          * Returns whatever the callback function returned on its successful,
1420          * iteration, or false on error, for example if the retry limit was
1421          * reached.
1422          */
1423         function deadlockLoop() {
1424                 $myFname = 'Database::deadlockLoop';
1425
1426                 $this->begin();
1427                 $args = func_get_args();
1428                 $function = array_shift( $args );
1429                 $oldIgnore = $this->ignoreErrors( true );
1430                 $tries = DEADLOCK_TRIES;
1431                 if ( is_array( $function ) ) {
1432                         $fname = $function[0];
1433                 } else {
1434                         $fname = $function;
1435                 }
1436                 do {
1437                         $retVal = call_user_func_array( $function, $args );
1438                         $error = $this->lastError();
1439                         $errno = $this->lastErrno();
1440                         $sql = $this->lastQuery();
1441
1442                         if ( $errno ) {
1443                                 if ( $this->wasDeadlock() ) {
1444                                         # Retry
1445                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1446                                 } else {
1447                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1448                                 }
1449                         }
1450                 } while( $this->wasDeadlock() && --$tries > 0 );
1451                 $this->ignoreErrors( $oldIgnore );
1452                 if ( $tries <= 0 ) {
1453                         $this->query( 'ROLLBACK', $myFname );
1454                         $this->reportQueryError( $error, $errno, $sql, $fname );
1455                         return false;
1456                 } else {
1457                         $this->query( 'COMMIT', $myFname );
1458                         return $retVal;
1459                 }
1460         }
1461
1462         /**
1463          * Do a SELECT MASTER_POS_WAIT()
1464          *
1465          * @param string $file the binlog file
1466          * @param string $pos the binlog position
1467          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1468          */
1469         function masterPosWait( $file, $pos, $timeout ) {
1470                 $fname = 'Database::masterPosWait';
1471                 wfProfileIn( $fname );
1472
1473
1474                 # Commit any open transactions
1475                 $this->immediateCommit();
1476
1477                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1478                 $encFile = $this->strencode( $file );
1479                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1480                 $res = $this->doQuery( $sql );
1481                 if ( $res && $row = $this->fetchRow( $res ) ) {
1482                         $this->freeResult( $res );
1483                         wfProfileOut( $fname );
1484                         return $row[0];
1485                 } else {
1486                         wfProfileOut( $fname );
1487                         return false;
1488                 }
1489         }
1490
1491         /**
1492          * Get the position of the master from SHOW SLAVE STATUS
1493          */
1494         function getSlavePos() {
1495                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1496                 $row = $this->fetchObject( $res );
1497                 if ( $row ) {
1498                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1499                 } else {
1500                         return array( false, false );
1501                 }
1502         }
1503
1504         /**
1505          * Get the position of the master from SHOW MASTER STATUS
1506          */
1507         function getMasterPos() {
1508                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1509                 $row = $this->fetchObject( $res );
1510                 if ( $row ) {
1511                         return array( $row->File, $row->Position );
1512                 } else {
1513                         return array( false, false );
1514                 }
1515         }
1516
1517         /**
1518          * Begin a transaction, or if a transaction has already started, continue it
1519          */
1520         function begin( $fname = 'Database::begin' ) {
1521                 if ( !$this->mTrxLevel ) {
1522                         $this->immediateBegin( $fname );
1523                 } else {
1524                         $this->mTrxLevel++;
1525                 }
1526         }
1527
1528         /**
1529          * End a transaction, or decrement the nest level if transactions are nested
1530          */
1531         function commit( $fname = 'Database::commit' ) {
1532                 if ( $this->mTrxLevel ) {
1533                         $this->mTrxLevel--;
1534                 }
1535                 if ( !$this->mTrxLevel ) {
1536                         $this->immediateCommit( $fname );
1537                 }
1538         }
1539
1540         /**
1541          * Rollback a transaction
1542          */
1543         function rollback( $fname = 'Database::rollback' ) {
1544                 $this->query( 'ROLLBACK', $fname );
1545                 $this->mTrxLevel = 0;
1546         }
1547
1548         /**
1549          * Begin a transaction, committing any previously open transaction
1550          */
1551         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1552                 $this->query( 'BEGIN', $fname );
1553                 $this->mTrxLevel = 1;
1554         }
1555
1556         /**
1557          * Commit transaction, if one is open
1558          */
1559         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1560                 $this->query( 'COMMIT', $fname );
1561                 $this->mTrxLevel = 0;
1562         }
1563
1564         /**
1565          * Return MW-style timestamp used for MySQL schema
1566          */
1567         function timestamp( $ts=0 ) {
1568                 return wfTimestamp(TS_MW,$ts);
1569         }
1570
1571         /**
1572          * Local database timestamp format or null
1573          */
1574         function timestampOrNull( $ts = null ) {
1575                 if( is_null( $ts ) ) {
1576                         return null;
1577                 } else {
1578                         return $this->timestamp( $ts );
1579                 }
1580         }
1581
1582         /**
1583          * @todo document
1584          */
1585         function resultObject( $result ) {
1586                 if( empty( $result ) ) {
1587                         return NULL;
1588                 } else {
1589                         return new ResultWrapper( $this, $result );
1590                 }
1591         }
1592
1593         /**
1594          * Return aggregated value alias
1595          */
1596         function aggregateValue ($valuedata,$valuename='value') {
1597                 return $valuename;
1598         }
1599
1600         /**
1601          * @return string wikitext of a link to the server software's web site
1602          */
1603         function getSoftwareLink() {
1604                 return "[http://www.mysql.com/ MySQL]";
1605         }
1606
1607         /**
1608          * @return string Version information from the database
1609          */
1610         function getServerVersion() {
1611                 return mysql_get_server_info();
1612         }
1613
1614         /**
1615          * Ping the server and try to reconnect if it there is no connection
1616          */
1617         function ping() {
1618                 if( function_exists( 'mysql_ping' ) ) {
1619                         return mysql_ping( $this->mConn );
1620                 } else {
1621                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1622                         return true;
1623                 }
1624         }
1625
1626         /**
1627          * Get slave lag.
1628          * At the moment, this will only work if the DB user has the PROCESS privilege
1629          */
1630         function getLag() {
1631                 $res = $this->query( 'SHOW PROCESSLIST' );
1632                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1633                 # dubious, but unfortunately there's no easy rigorous way
1634                 $slaveThreads = 0;
1635                 while ( $row = $this->fetchObject( $res ) ) {
1636                         if ( $row->User == 'system user' ) {
1637                                 if ( ++$slaveThreads == 2 ) {
1638                                         # This is it, return the time (except -ve)
1639                                         if ( $row->Time > 0x7fffffff ) {
1640                                                 return false;
1641                                         } else {
1642                                                 return $row->Time;
1643                                         }
1644                                 }
1645                         }
1646                 }
1647                 return false;
1648         }
1649
1650         /**
1651          * Get status information from SHOW STATUS in an associative array
1652          */
1653         function getStatus($which="%") {
1654                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1655                 $status = array();
1656                 while ( $row = $this->fetchObject( $res ) ) {
1657                         $status[$row->Variable_name] = $row->Value;
1658                 }
1659                 return $status;
1660         }
1661
1662         /**
1663          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1664          */
1665         function maxListLen() {
1666                 return 0;
1667         }
1668
1669         function encodeBlob($b) {
1670                 return $b;
1671         }
1672
1673         /**
1674          * Read and execute SQL commands from a file.
1675          * Returns true on success, error string on failure
1676          */
1677         function sourceFile( $filename ) {
1678                 $fp = fopen( $filename, 'r' );
1679                 if ( false === $fp ) {
1680                         return "Could not open \"{$fname}\".\n";
1681                 }
1682
1683                 $cmd = "";
1684                 $done = false;
1685                 $dollarquote = false;
1686
1687                 while ( ! feof( $fp ) ) {
1688                         $line = trim( fgets( $fp, 1024 ) );
1689                         $sl = strlen( $line ) - 1;
1690
1691                         if ( $sl < 0 ) { continue; }
1692                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
1693
1694                         ## Allow dollar quoting for function declarations
1695                         if (substr($line,0,4) == '$mw$') {
1696                                 if ($dollarquote) {
1697                                         $dollarquote = false;
1698                                         $done = true;
1699                                 }
1700                                 else {
1701                                         $dollarquote = true;
1702                                 }
1703                         }
1704                         else if (!$dollarquote) {
1705                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
1706                                         $done = true;
1707                                         $line = substr( $line, 0, $sl );
1708                                 }
1709                         }
1710
1711                         if ( '' != $cmd ) { $cmd .= ' '; }
1712                         $cmd .= "$line\n";
1713
1714                         if ( $done ) {
1715                                 $cmd = str_replace(';;', ";", $cmd);
1716                                 $cmd = $this->replaceVars( $cmd );
1717                                 $res = $this->query( $cmd, 'dbsource', true );
1718
1719                                 if ( false === $res ) {
1720                                         $err = $this->lastError();
1721                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
1722                                 }
1723
1724                                 $cmd = '';
1725                                 $done = false;
1726                         }
1727                 }
1728                 fclose( $fp );
1729                 return true;
1730         }
1731
1732         /**
1733          * Replace variables in sourced SQL
1734          */
1735         function replaceVars( $ins ) {
1736                 $varnames = array(
1737                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
1738                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
1739                         'wgDBadminuser', 'wgDBadminpassword',
1740                 );
1741
1742                 // Ordinary variables
1743                 foreach ( $varnames as $var ) {
1744                         if( isset( $GLOBALS[$var] ) ) {
1745                                 $val = addslashes( $GLOBALS[$var] );
1746                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
1747                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
1748                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
1749                         }
1750                 }
1751
1752                 // Table prefixes
1753                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
1754                         array( &$this, 'tableNameCallback' ), $ins );
1755                 return $ins;
1756         }
1757
1758         /**
1759          * Table name callback
1760          * @private
1761          */
1762         function tableNameCallback( $matches ) {
1763                 return $this->tableName( $matches[1] );
1764         }
1765
1766 }
1767
1768 /**
1769  * Database abstraction object for mySQL
1770  * Inherit all methods and properties of Database::Database()
1771  *
1772  * @package MediaWiki
1773  * @see Database
1774  */
1775 class DatabaseMysql extends Database {
1776         # Inherit all
1777 }
1778
1779
1780 /**
1781  * Result wrapper for grabbing data queried by someone else
1782  *
1783  * @package MediaWiki
1784  */
1785 class ResultWrapper {
1786         var $db, $result;
1787
1788         /**
1789          * @todo document
1790          */
1791         function ResultWrapper( &$database, $result ) {
1792                 $this->db =& $database;
1793                 $this->result =& $result;
1794         }
1795
1796         /**
1797          * @todo document
1798          */
1799         function numRows() {
1800                 return $this->db->numRows( $this->result );
1801         }
1802
1803         /**
1804          * @todo document
1805          */
1806         function fetchObject() {
1807                 return $this->db->fetchObject( $this->result );
1808         }
1809
1810         /**
1811          * @todo document
1812          */
1813         function &fetchRow() {
1814                 return $this->db->fetchRow( $this->result );
1815         }
1816
1817         /**
1818          * @todo document
1819          */
1820         function free() {
1821                 $this->db->freeResult( $this->result );
1822                 unset( $this->result );
1823                 unset( $this->db );
1824         }
1825
1826         function seek( $row ) {
1827                 $this->db->dataSeek( $this->result, $row );
1828         }
1829
1830 }
1831
1832
1833 #------------------------------------------------------------------------------
1834 # Global functions
1835 #------------------------------------------------------------------------------
1836
1837 /**
1838  * Standard fail function, called by default when a connection cannot be
1839  * established.
1840  * Displays the file cache if possible
1841  */
1842 function wfEmergencyAbort( &$conn, $error ) {
1843         global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgOutputEncoding;
1844         global $wgSitename, $wgServer, $wgMessageCache, $wgLogo;
1845
1846         # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
1847         # Hard coding strings instead.
1848
1849         $noconnect = "<h1><img src='$wgLogo' style='float:left;margin-right:1em' alt=''>$wgSitename has a problem</h1><p><strong>Sorry! This site is experiencing technical difficulties.</strong></p><p>Try waiting a few minutes and reloading.</p><p><small>(Can't contact the database server: $1)</small></p>";
1850         $mainpage = 'Main Page';
1851         $searchdisabled = <<<EOT
1852 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
1853 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
1854 EOT;
1855
1856         $googlesearch = "
1857 <!-- SiteSearch Google -->
1858 <FORM method=GET action=\"http://www.google.com/search\">
1859 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
1860 <A HREF=\"http://www.google.com/\">
1861 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
1862 border=\"0\" ALT=\"Google\"></A>
1863 </td>
1864 <td>
1865 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
1866 <INPUT type=submit name=btnG VALUE=\"Google Search\">
1867 <font size=-1>
1868 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
1869 <input type='hidden' name='ie' value='$2'>
1870 <input type='hidden' name='oe' value='$2'>
1871 </font>
1872 </td></tr></TABLE>
1873 </FORM>
1874 <!-- SiteSearch Google -->";
1875         $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
1876
1877
1878         if( !headers_sent() ) {
1879                 header( 'HTTP/1.0 500 Internal Server Error' );
1880                 header( 'Content-type: text/html; charset='.$wgOutputEncoding );
1881                 /* Don't cache error pages!  They cause no end of trouble... */
1882                 header( 'Cache-control: none' );
1883                 header( 'Pragma: nocache' );
1884         }
1885
1886         # No database access
1887         if ( is_object( $wgMessageCache ) ) {
1888                 $wgMessageCache->disable();
1889         }
1890
1891         if ( trim( $error ) == '' ) {
1892                 $error = $this->mServer;
1893         }
1894
1895         wfLogDBError( "Connection error: $error\n" );
1896
1897         $text = str_replace( '$1', $error, $noconnect );
1898         $text .= wfGetSiteNotice();
1899
1900         if($wgUseFileCache) {
1901                 if($wgTitle) {
1902                         $t =& $wgTitle;
1903                 } else {
1904                         if($title) {
1905                                 $t = Title::newFromURL( $title );
1906                         } elseif (@/**/$_REQUEST['search']) {
1907                                 $search = $_REQUEST['search'];
1908                                 echo $searchdisabled;
1909                                 echo str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
1910                                   $wgInputEncoding ), $googlesearch );
1911                                 wfErrorExit();
1912                         } else {
1913                                 $t = Title::newFromText( $mainpage );
1914                         }
1915                 }
1916
1917                 $cache = new CacheManager( $t );
1918                 if( $cache->isFileCached() ) {
1919                         $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
1920                                 $cachederror . "</b></p>\n";
1921
1922                         $tag = '<div id="article">';
1923                         $text = str_replace(
1924                                 $tag,
1925                                 $tag . $msg,
1926                                 $cache->fetchPageText() );
1927                 }
1928         }
1929
1930         echo $text;
1931         wfErrorExit();
1932 }
1933
1934 ?>