includes/Database.php

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