includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  */
   6
   7 /** Number of times to re-try an operation in case of deadlock */
   8 define( 'DEADLOCK_TRIES', 4 );
   9 /** Minimum time to wait before retry, in microseconds */
  10 define( 'DEADLOCK_DELAY_MIN', 500000 );
  11 /** Maximum time to wait before retry */
  12 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  13
  14 /**
  15  * Database abstraction object
  16  * @addtogroup Database
  17  */
  18 class Database {
  19
  20 #------------------------------------------------------------------------------
  21 # Variables
  22 #------------------------------------------------------------------------------
  23
  24         protected $mLastQuery = '';
  25
  26         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  27         protected $mOut, $mOpened = false;
  28
  29         protected $mFailFunction;
  30         protected $mTablePrefix;
  31         protected $mFlags;
  32         protected $mTrxLevel = 0;
  33         protected $mErrorCount = 0;
  34         protected $mLBInfo = array();
  35         protected $mFakeSlaveLag = null, $mFakeMaster = false;
  36
  37 #------------------------------------------------------------------------------
  38 # Accessors
  39 #------------------------------------------------------------------------------
  40         # These optionally set a variable and return the previous state
  41
  42         /**
  43          * Fail function, takes a Database as a parameter
  44          * Set to false for default, 1 for ignore errors
  45          */
  46         function failFunction( $function = NULL ) {
  47                 return wfSetVar( $this->mFailFunction, $function );
  48         }
  49
  50         /**
  51          * Output page, used for reporting errors
  52          * FALSE means discard output
  53          */
  54         function setOutputPage( $out ) {
  55                 $this->mOut = $out;
  56         }
  57
  58         /**
  59          * Boolean, controls output of large amounts of debug information
  60          */
  61         function debug( $debug = NULL ) {
  62                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  63         }
  64
  65         /**
  66          * Turns buffering of SQL result sets on (true) or off (false).
  67          * Default is "on" and it should not be changed without good reasons.
  68          */
  69         function bufferResults( $buffer = NULL ) {
  70                 if ( is_null( $buffer ) ) {
  71                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  72                 } else {
  73                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  74                 }
  75         }
  76
  77         /**
  78          * Turns on (false) or off (true) the automatic generation and sending
  79          * of a "we're sorry, but there has been a database error" page on
  80          * database errors. Default is on (false). When turned off, the
  81          * code should use lastErrno() and lastError() to handle the
  82          * situation as appropriate.
  83          */
  84         function ignoreErrors( $ignoreErrors = NULL ) {
  85                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  86         }
  87
  88         /**
  89          * The current depth of nested transactions
  90          * @param $level Integer: , default NULL.
  91          */
  92         function trxLevel( $level = NULL ) {
  93                 return wfSetVar( $this->mTrxLevel, $level );
  94         }
  95
  96         /**
  97          * Number of errors logged, only useful when errors are ignored
  98          */
  99         function errorCount( $count = NULL ) {
 100                 return wfSetVar( $this->mErrorCount, $count );
 101         }
 102
 103         function tablePrefix( $prefix = null ) {
 104                 return wfSetVar( $this->mTablePrefix, $prefix );
 105         }
 106
 107         /**
 108          * Properties passed down from the server info array of the load balancer
 109          */
 110         function getLBInfo( $name = NULL ) {
 111                 if ( is_null( $name ) ) {
 112                         return $this->mLBInfo;
 113                 } else {
 114                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 115                                 return $this->mLBInfo[$name];
 116                         } else {
 117                                 return NULL;
 118                         }
 119                 }
 120         }
 121
 122         function setLBInfo( $name, $value = NULL ) {
 123                 if ( is_null( $value ) ) {
 124                         $this->mLBInfo = $name;
 125                 } else {
 126                         $this->mLBInfo[$name] = $value;
 127                 }
 128         }
 129
 130         /**
 131          * Set lag time in seconds for a fake slave
 132          */
 133         function setFakeSlaveLag( $lag ) {
 134                 $this->mFakeSlaveLag = $lag;
 135         }
 136
 137         /**
 138          * Make this connection a fake master
 139          */
 140         function setFakeMaster( $enabled = true ) {
 141                 $this->mFakeMaster = $enabled;
 142         }
 143
 144         /**
 145          * Returns true if this database supports (and uses) cascading deletes
 146          */
 147         function cascadingDeletes() {
 148                 return false;
 149         }
 150
 151         /**
 152          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 153          */
 154         function cleanupTriggers() {
 155                 return false;
 156         }
 157
 158         /**
 159          * Returns true if this database is strict about what can be put into an IP field.
 160          * Specifically, it uses a NULL value instead of an empty string.
 161          */
 162         function strictIPs() {
 163                 return false;
 164         }
 165
 166         /**
 167          * Returns true if this database uses timestamps rather than integers
 168         */
 169         function realTimestamps() {
 170                 return false;
 171         }
 172
 173         /**
 174          * Returns true if this database does an implicit sort when doing GROUP BY
 175          */
 176         function implicitGroupby() {
 177                 return true;
 178         }
 179
 180         /**
 181          * Returns true if this database does an implicit order by when the column has an index
 182          * For example: SELECT page_title FROM page LIMIT 1
 183          */
 184         function implicitOrderby() {
 185                 return true;
 186         }
 187
 188         /**
 189          * Returns true if this database can do a native search on IP columns
 190          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 191          */
 192         function searchableIPs() {
 193                 return false;
 194         }
 195
 196         /**
 197          * Returns true if this database can use functional indexes
 198          */
 199         function functionalIndexes() {
 200                 return false;
 201         }
 202
 203         /**#@+
 204          * Get function
 205          */
 206         function lastQuery() { return $this->mLastQuery; }
 207         function isOpen() { return $this->mOpened; }
 208         /**#@-*/
 209
 210         function setFlag( $flag ) {
 211                 $this->mFlags |= $flag;
 212         }
 213
 214         function clearFlag( $flag ) {
 215                 $this->mFlags &= ~$flag;
 216         }
 217
 218         function getFlag( $flag ) {
 219                 return !!($this->mFlags & $flag);
 220         }
 221
 222         /**
 223          * General read-only accessor
 224          */
 225         function getProperty( $name ) {
 226                 return $this->$name;
 227         }
 228
 229         function getWikiID() {
 230                 if( $this->mTablePrefix ) {
 231                         return "{$this->mDBname}-{$this->mTablePrefix}";
 232                 } else {
 233                         return $this->mDBname;
 234                 }
 235         }
 236
 237 #------------------------------------------------------------------------------
 238 # Other functions
 239 #------------------------------------------------------------------------------
 240
 241         /**@{{
 242          * Constructor.
 243          * @param string $server database server host
 244          * @param string $user database user name
 245          * @param string $password database user password
 246          * @param string $dbname database name
 247          * @param failFunction
 248          * @param $flags
 249          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 250          */
 251         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 252                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 253
 254                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 255                 # Can't get a reference if it hasn't been set yet
 256                 if ( !isset( $wgOut ) ) {
 257                         $wgOut = NULL;
 258                 }
 259                 $this->mOut =& $wgOut;
 260
 261                 $this->mFailFunction = $failFunction;
 262                 $this->mFlags = $flags;
 263
 264                 if ( $this->mFlags & DBO_DEFAULT ) {
 265                         if ( $wgCommandLineMode ) {
 266                                 $this->mFlags &= ~DBO_TRX;
 267                         } else {
 268                                 $this->mFlags |= DBO_TRX;
 269                         }
 270                 }
 271
 272                 /*
 273                 // Faster read-only access
 274                 if ( wfReadOnly() ) {
 275                         $this->mFlags |= DBO_PERSISTENT;
 276                         $this->mFlags &= ~DBO_TRX;
 277                 }*/
 278
 279                 /** Get the default table prefix*/
 280                 if ( $tablePrefix == 'get from global' ) {
 281                         $this->mTablePrefix = $wgDBprefix;
 282                 } else {
 283                         $this->mTablePrefix = $tablePrefix;
 284                 }
 285
 286                 if ( $server ) {
 287                         $this->open( $server, $user, $password, $dbName );
 288                 }
 289         }
 290
 291         /**
 292          * @static
 293          * @param failFunction
 294          * @param $flags
 295          */
 296         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 297         {
 298                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 299         }
 300
 301         /**
 302          * Usually aborts on failure
 303          * If the failFunction is set to a non-zero integer, returns success
 304          */
 305         function open( $server, $user, $password, $dbName ) {
 306                 global $wguname, $wgAllDBsAreLocalhost;
 307                 wfProfileIn( __METHOD__ );
 308
 309                 # Test for missing mysql.so
 310                 # First try to load it
 311                 if (!@extension_loaded('mysql')) {
 312                         @dl('mysql.so');
 313                 }
 314
 315                 # Fail now
 316                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 317                 if ( !function_exists( 'mysql_connect' ) ) {
 318                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 319                 }
 320
 321                 # Debugging hack -- fake cluster
 322                 if ( $wgAllDBsAreLocalhost ) {
 323                         $realServer = 'localhost';
 324                 } else {
 325                         $realServer = $server;
 326                 }
 327                 $this->close();
 328                 $this->mServer = $server;
 329                 $this->mUser = $user;
 330                 $this->mPassword = $password;
 331                 $this->mDBname = $dbName;
 332
 333                 $success = false;
 334
 335                 wfProfileIn("dbconnect-$server");
 336
 337                 # Try to connect up to three times
 338                 # The kernel's default SYN retransmission period is far too slow for us,
 339                 # so we use a short timeout plus a manual retry.
 340                 $this->mConn = false;
 341                 $max = 3;
 342                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 343                         if ( $i > 1 ) {
 344                                 usleep( 1000 );
 345                         }
 346                         if ( $this->mFlags & DBO_PERSISTENT ) {
 347                                 @/**/$this->mConn = mysql_pconnect( $realServer, $user, $password );
 348                         } else {
 349                                 # Create a new connection...
 350                                 @/**/$this->mConn = mysql_connect( $realServer, $user, $password, true );
 351                         }
 352                         if ($this->mConn === false) {
 353                                 #$iplus = $i + 1;
 354                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 355                         }
 356                 }
 357
 358                 wfProfileOut("dbconnect-$server");
 359
 360                 if ( $dbName != '' ) {
 361                         if ( $this->mConn !== false ) {
 362                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 363                                 if ( !$success ) {
 364                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 365                                                 "from client host {$wguname['nodename']}\n";
 366                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 367                                         wfDebug( $error );
 368                                 }
 369                         } else {
 370                                 wfDebug( "DB connection error\n" );
 371                                 wfDebug( "Server: $server, User: $user, Password: " .
 372                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 373                                 $success = false;
 374                         }
 375                 } else {
 376                         # Delay USE query
 377                         $success = (bool)$this->mConn;
 378                 }
 379
 380                 if ( $success ) {
 381                         $version = $this->getServerVersion();
 382                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 383                                 // Tell the server we're communicating with it in UTF-8.
 384                                 // This may engage various charset conversions.
 385                                 global $wgDBmysql5;
 386                                 if( $wgDBmysql5 ) {
 387                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 388                                 }
 389                                 // Turn off strict mode
 390                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 391                         }
 392
 393                         // Turn off strict mode if it is on
 394                 } else {
 395                         $this->reportConnectionError();
 396                 }
 397
 398                 $this->mOpened = $success;
 399                 wfProfileOut( __METHOD__ );
 400                 return $success;
 401         }
 402         /**@}}*/
 403
 404         /**
 405          * Closes a database connection.
 406          * if it is open : commits any open transactions
 407          *
 408          * @return bool operation success. true if already closed.
 409          */
 410         function close()
 411         {
 412                 $this->mOpened = false;
 413                 if ( $this->mConn ) {
 414                         if ( $this->trxLevel() ) {
 415                                 $this->immediateCommit();
 416                         }
 417                         return mysql_close( $this->mConn );
 418                 } else {
 419                         return true;
 420                 }
 421         }
 422
 423         /**
 424          * @param string $error fallback error message, used if none is given by MySQL
 425          */
 426         function reportConnectionError( $error = 'Unknown error' ) {
 427                 $myError = $this->lastError();
 428                 if ( $myError ) {
 429                         $error = $myError;
 430                 }
 431
 432                 if ( $this->mFailFunction ) {
 433                         # Legacy error handling method
 434                         if ( !is_int( $this->mFailFunction ) ) {
 435                                 $ff = $this->mFailFunction;
 436                                 $ff( $this, $error );
 437                         }
 438                 } else {
 439                         # New method
 440                         wfLogDBError( "Connection error: $error\n" );
 441                         throw new DBConnectionError( $this, $error );
 442                 }
 443         }
 444
 445         /**
 446          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 447          *
 448          * @param  $sql        String: SQL query
 449          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 450          *     comment (you can use __METHOD__ or add some extra info)
 451          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 452          *     maybe best to catch the exception instead?
 453          * @return true for a successful write query, ResultWrapper object for a successful read query,
 454          *     or false on failure if $tempIgnore set
 455          * @throws DBQueryError Thrown when the database returns an error of any kind
 456          */
 457         public function query( $sql, $fname = '', $tempIgnore = false ) {
 458                 global $wgProfiler;
 459
 460                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 461                 if ( isset( $wgProfiler ) ) {
 462                         # generalizeSQL will probably cut down the query to reasonable
 463                         # logging size most of the time. The substr is really just a sanity check.
 464
 465                         # Who's been wasting my precious column space? -- TS
 466                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 467
 468                         if ( $isMaster ) {
 469                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 470                                 $totalProf = 'Database::query-master';
 471                         } else {
 472                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 473                                 $totalProf = 'Database::query';
 474                         }
 475                         wfProfileIn( $totalProf );
 476                         wfProfileIn( $queryProf );
 477                 }
 478
 479                 $this->mLastQuery = $sql;
 480
 481                 # Add a comment for easy SHOW PROCESSLIST interpretation
 482                 #if ( $fname ) {
 483                         global $wgUser;
 484                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 485                                 $userName = $wgUser->getName();
 486                                 if ( mb_strlen( $userName ) > 15 ) {
 487                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 488                                 }
 489                                 $userName = str_replace( '/', '', $userName );
 490                         } else {
 491                                 $userName = '';
 492                         }
 493                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 494                 #} else {
 495                 #       $commentedSql = $sql;
 496                 #}
 497
 498                 # If DBO_TRX is set, start a transaction
 499                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 500                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 501                         // avoid establishing transactions for SHOW and SET statements too -
 502                         // that would delay transaction initializations to once connection
 503                         // is really used by application
 504                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 505                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 506                                 $this->begin();
 507                 }
 508
 509                 if ( $this->debug() ) {
 510                         $sqlx = substr( $commentedSql, 0, 500 );
 511                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 512                         if ( $isMaster ) {
 513                                 wfDebug( "SQL-master: $sqlx\n" );
 514                         } else {
 515                                 wfDebug( "SQL: $sqlx\n" );
 516                         }
 517                 }
 518
 519                 # Do the query and handle errors
 520                 $ret = $this->doQuery( $commentedSql );
 521
 522                 # Try reconnecting if the connection was lost
 523                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 524                         # Transaction is gone, like it or not
 525                         $this->mTrxLevel = 0;
 526                         wfDebug( "Connection lost, reconnecting...\n" );
 527                         if ( $this->ping() ) {
 528                                 wfDebug( "Reconnected\n" );
 529                                 $sqlx = substr( $commentedSql, 0, 500 );
 530                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 531                                 global $wgRequestTime;
 532                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 533                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 534                                 $ret = $this->doQuery( $commentedSql );
 535                         } else {
 536                                 wfDebug( "Failed\n" );
 537                         }
 538                 }
 539
 540                 if ( false === $ret ) {
 541                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 542                 }
 543
 544                 if ( isset( $wgProfiler ) ) {
 545                         wfProfileOut( $queryProf );
 546                         wfProfileOut( $totalProf );
 547                 }
 548                 return $this->resultObject( $ret );
 549         }
 550
 551         /**
 552          * The DBMS-dependent part of query()
 553          * @param  $sql String: SQL query.
 554          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 555          * @access private
 556          */
 557         /*private*/ function doQuery( $sql ) {
 558                 if( $this->bufferResults() ) {
 559                         $ret = mysql_query( $sql, $this->mConn );
 560                 } else {
 561                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 562                 }
 563                 return $ret;
 564         }
 565
 566         /**
 567          * @param $error
 568          * @param $errno
 569          * @param $sql
 570          * @param string $fname
 571          * @param bool $tempIgnore
 572          */
 573         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 574                 global $wgCommandLineMode;
 575                 # Ignore errors during error handling to avoid infinite recursion
 576                 $ignore = $this->ignoreErrors( true );
 577                 ++$this->mErrorCount;
 578
 579                 if( $ignore || $tempIgnore ) {
 580                         wfDebug("SQL ERROR (ignored): $error\n");
 581                         $this->ignoreErrors( $ignore );
 582                 } else {
 583                         $sql1line = str_replace( "\n", "\\n", $sql );
 584                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 585                         wfDebug("SQL ERROR: " . $error . "\n");
 586                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 587                 }
 588         }
 589
 590
 591         /**
 592          * Intended to be compatible with the PEAR::DB wrapper functions.
 593          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 594          *
 595          * ? = scalar value, quoted as necessary
 596          * ! = raw SQL bit (a function for instance)
 597          * & = filename; reads the file and inserts as a blob
 598          *     (we don't use this though...)
 599          */
 600         function prepare( $sql, $func = 'Database::prepare' ) {
 601                 /* MySQL doesn't support prepared statements (yet), so just
 602                    pack up the query for reference. We'll manually replace
 603                    the bits later. */
 604                 return array( 'query' => $sql, 'func' => $func );
 605         }
 606
 607         function freePrepared( $prepared ) {
 608                 /* No-op for MySQL */
 609         }
 610
 611         /**
 612          * Execute a prepared query with the various arguments
 613          * @param string $prepared the prepared sql
 614          * @param mixed $args Either an array here, or put scalars as varargs
 615          */
 616         function execute( $prepared, $args = null ) {
 617                 if( !is_array( $args ) ) {
 618                         # Pull the var args
 619                         $args = func_get_args();
 620                         array_shift( $args );
 621                 }
 622                 $sql = $this->fillPrepared( $prepared['query'], $args );
 623                 return $this->query( $sql, $prepared['func'] );
 624         }
 625
 626         /**
 627          * Prepare & execute an SQL statement, quoting and inserting arguments
 628          * in the appropriate places.
 629          * @param string $query
 630          * @param string $args ...
 631          */
 632         function safeQuery( $query, $args = null ) {
 633                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 634                 if( !is_array( $args ) ) {
 635                         # Pull the var args
 636                         $args = func_get_args();
 637                         array_shift( $args );
 638                 }
 639                 $retval = $this->execute( $prepared, $args );
 640                 $this->freePrepared( $prepared );
 641                 return $retval;
 642         }
 643
 644         /**
 645          * For faking prepared SQL statements on DBs that don't support
 646          * it directly.
 647          * @param string $preparedSql - a 'preparable' SQL statement
 648          * @param array $args - array of arguments to fill it with
 649          * @return string executable SQL
 650          */
 651         function fillPrepared( $preparedQuery, $args ) {
 652                 reset( $args );
 653                 $this->preparedArgs =& $args;
 654                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 655                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 656         }
 657
 658         /**
 659          * preg_callback func for fillPrepared()
 660          * The arguments should be in $this->preparedArgs and must not be touched
 661          * while we're doing this.
 662          *
 663          * @param array $matches
 664          * @return string
 665          * @private
 666          */
 667         function fillPreparedArg( $matches ) {
 668                 switch( $matches[1] ) {
 669                         case '\\?': return '?';
 670                         case '\\!': return '!';
 671                         case '\\&': return '&';
 672                 }
 673                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 674                 switch( $matches[1] ) {
 675                         case '?': return $this->addQuotes( $arg );
 676                         case '!': return $arg;
 677                         case '&':
 678                                 # return $this->addQuotes( file_get_contents( $arg ) );
 679                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 680                         default:
 681                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 682                 }
 683         }
 684
 685         /**#@+
 686          * @param mixed $res A SQL result
 687          */
 688         /**
 689          * Free a result object
 690          */
 691         function freeResult( $res ) {
 692                 if ( $res instanceof ResultWrapper ) {
 693                         $res = $res->result;
 694                 }
 695                 if ( !@/**/mysql_free_result( $res ) ) {
 696                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 697                 }
 698         }
 699
 700         /**
 701          * Fetch the next row from the given result object, in object form.
 702          * Fields can be retrieved with $row->fieldname, with fields acting like
 703          * member variables.
 704          *
 705          * @param $res SQL result object as returned from Database::query(), etc.
 706          * @return MySQL row object
 707          * @throws DBUnexpectedError Thrown if the database returns an error
 708          */
 709         function fetchObject( $res ) {
 710                 if ( $res instanceof ResultWrapper ) {
 711                         $res = $res->result;
 712                 }
 713                 @/**/$row = mysql_fetch_object( $res );
 714                 if( $this->lastErrno() ) {
 715                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 716                 }
 717                 return $row;
 718         }
 719
 720         /**
 721          * Fetch the next row from the given result object, in associative array
 722          * form.  Fields are retrieved with $row['fieldname'].
 723          *
 724          * @param $res SQL result object as returned from Database::query(), etc.
 725          * @return MySQL row object
 726          * @throws DBUnexpectedError Thrown if the database returns an error
 727          */
 728         function fetchRow( $res ) {
 729                 if ( $res instanceof ResultWrapper ) {
 730                         $res = $res->result;
 731                 }
 732                 @/**/$row = mysql_fetch_array( $res );
 733                 if ( $this->lastErrno() ) {
 734                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 735                 }
 736                 return $row;
 737         }
 738
 739         /**
 740          * Get the number of rows in a result object
 741          */
 742         function numRows( $res ) {
 743                 if ( $res instanceof ResultWrapper ) {
 744                         $res = $res->result;
 745                 }
 746                 @/**/$n = mysql_num_rows( $res );
 747                 if( $this->lastErrno() ) {
 748                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 749                 }
 750                 return $n;
 751         }
 752
 753         /**
 754          * Get the number of fields in a result object
 755          * See documentation for mysql_num_fields()
 756          */
 757         function numFields( $res ) {
 758                 if ( $res instanceof ResultWrapper ) {
 759                         $res = $res->result;
 760                 }
 761                 return mysql_num_fields( $res );
 762         }
 763
 764         /**
 765          * Get a field name in a result object
 766          * See documentation for mysql_field_name():
 767          * http://www.php.net/mysql_field_name
 768          */
 769         function fieldName( $res, $n ) {
 770                 if ( $res instanceof ResultWrapper ) {
 771                         $res = $res->result;
 772                 }
 773                 return mysql_field_name( $res, $n );
 774         }
 775
 776         /**
 777          * Get the inserted value of an auto-increment row
 778          *
 779          * The value inserted should be fetched from nextSequenceValue()
 780          *
 781          * Example:
 782          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 783          * $dbw->insert('page',array('page_id' => $id));
 784          * $id = $dbw->insertId();
 785          */
 786         function insertId() { return mysql_insert_id( $this->mConn ); }
 787
 788         /**
 789          * Change the position of the cursor in a result object
 790          * See mysql_data_seek()
 791          */
 792         function dataSeek( $res, $row ) {
 793                 if ( $res instanceof ResultWrapper ) {
 794                         $res = $res->result;
 795                 }
 796                 return mysql_data_seek( $res, $row );
 797         }
 798
 799         /**
 800          * Get the last error number
 801          * See mysql_errno()
 802          */
 803         function lastErrno() {
 804                 if ( $this->mConn ) {
 805                         return mysql_errno( $this->mConn );
 806                 } else {
 807                         return mysql_errno();
 808                 }
 809         }
 810
 811         /**
 812          * Get a description of the last error
 813          * See mysql_error() for more details
 814          */
 815         function lastError() {
 816                 if ( $this->mConn ) {
 817                         # Even if it's non-zero, it can still be invalid
 818                         wfSuppressWarnings();
 819                         $error = mysql_error( $this->mConn );
 820                         if ( !$error ) {
 821                                 $error = mysql_error();
 822                         }
 823                         wfRestoreWarnings();
 824                 } else {
 825                         $error = mysql_error();
 826                 }
 827                 if( $error ) {
 828                         $error .= ' (' . $this->mServer . ')';
 829                 }
 830                 return $error;
 831         }
 832         /**
 833          * Get the number of rows affected by the last write query
 834          * See mysql_affected_rows() for more details
 835          */
 836         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 837         /**#@-*/ // end of template : @param $result
 838
 839         /**
 840          * Simple UPDATE wrapper
 841          * Usually aborts on failure
 842          * If errors are explicitly ignored, returns success
 843          *
 844          * This function exists for historical reasons, Database::update() has a more standard
 845          * calling convention and feature set
 846          */
 847         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 848         {
 849                 $table = $this->tableName( $table );
 850                 $sql = "UPDATE $table SET $var = '" .
 851                   $this->strencode( $value ) . "' WHERE ($cond)";
 852                 return (bool)$this->query( $sql, $fname );
 853         }
 854
 855         /**
 856          * Simple SELECT wrapper, returns a single field, input must be encoded
 857          * Usually aborts on failure
 858          * If errors are explicitly ignored, returns FALSE on failure
 859          */
 860         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 861                 if ( !is_array( $options ) ) {
 862                         $options = array( $options );
 863                 }
 864                 $options['LIMIT'] = 1;
 865
 866                 $res = $this->select( $table, $var, $cond, $fname, $options );
 867                 if ( $res === false || !$this->numRows( $res ) ) {
 868                         return false;
 869                 }
 870                 $row = $this->fetchRow( $res );
 871                 if ( $row !== false ) {
 872                         $this->freeResult( $res );
 873                         return $row[0];
 874                 } else {
 875                         return false;
 876                 }
 877         }
 878
 879         /**
 880          * Returns an optional USE INDEX clause to go after the table, and a
 881          * string to go at the end of the query
 882          *
 883          * @private
 884          *
 885          * @param array $options an associative array of options to be turned into
 886          *              an SQL query, valid keys are listed in the function.
 887          * @return array
 888          */
 889         function makeSelectOptions( $options ) {
 890                 $preLimitTail = $postLimitTail = '';
 891                 $startOpts = '';
 892
 893                 $noKeyOptions = array();
 894                 foreach ( $options as $key => $option ) {
 895                         if ( is_numeric( $key ) ) {
 896                                 $noKeyOptions[$option] = true;
 897                         }
 898                 }
 899
 900                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 901                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 902                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 903
 904                 //if (isset($options['LIMIT'])) {
 905                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 906                 //              isset($options['OFFSET']) ? $options['OFFSET']
 907                 //              : false);
 908                 //}
 909
 910                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 911                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 912                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 913
 914                 # Various MySQL extensions
 915                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 916                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 917                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 918                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 919                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 920                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 921                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 922                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 923
 924                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 925                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 926                 } else {
 927                         $useIndex = '';
 928                 }
 929
 930                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 931         }
 932
 933         /**
 934          * SELECT wrapper
 935          *
 936          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 937          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 938          * @param mixed  $conds   Array or string, condition(s) for WHERE
 939          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 940          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 941          *                        see Database::makeSelectOptions code for list of supported stuff
 942          * @param array $join_conds Associative array of table join conditions (optional)
 943          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 944          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
 945          */
 946         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() )
 947         {
 948                 if( is_array( $vars ) ) {
 949                         $vars = implode( ',', $vars );
 950                 }
 951                 if( !is_array( $options ) ) {
 952                         $options = array( $options );
 953                 }
 954                 if( is_array( $table ) ) {
 955                         if ( !empty($join_conds) || is_array( @$options['USE INDEX'] ) )
 956                                 $from = ' FROM ' . $this->tableNamesWithUseIndexOrJOIN( $table, @$options['USE INDEX'], $join_conds );
 957                         else
 958                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 959                 } elseif ($table!='') {
 960                         if ($table{0}==' ') {
 961                                 $from = ' FROM ' . $table;
 962                         } else {
 963                                 $from = ' FROM ' . $this->tableName( $table );
 964                         }
 965                 } else {
 966                         $from = '';
 967                 }
 968
 969                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
 970
 971                 if( !empty( $conds ) ) {
 972                         if ( is_array( $conds ) ) {
 973                                 $conds = $this->makeList( $conds, LIST_AND );
 974                         }
 975                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
 976                 } else {
 977                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
 978                 }
 979
 980                 if (isset($options['LIMIT']))
 981                         $sql = $this->limitResult($sql, $options['LIMIT'],
 982                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 983                 $sql = "$sql $postLimitTail";
 984
 985                 if (isset($options['EXPLAIN'])) {
 986                         $sql = 'EXPLAIN ' . $sql;
 987                 }
 988                 return $this->query( $sql, $fname );
 989         }
 990
 991         /**
 992          * Single row SELECT wrapper
 993          * Aborts or returns FALSE on error
 994          *
 995          * $vars: the selected variables
 996          * $conds: a condition map, terms are ANDed together.
 997          *   Items with numeric keys are taken to be literal conditions
 998          * Takes an array of selected variables, and a condition map, which is ANDed
 999          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1000          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1001          * $obj- >page_id is the ID of the Astronomy article
1002          *
1003          * @todo migrate documentation to phpdocumentor format
1004          */
1005         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
1006                 $options['LIMIT'] = 1;
1007                 $res = $this->select( $table, $vars, $conds, $fname, $options );
1008                 if ( $res === false )
1009                         return false;
1010                 if ( !$this->numRows($res) ) {
1011                         $this->freeResult($res);
1012                         return false;
1013                 }
1014                 $obj = $this->fetchObject( $res );
1015                 $this->freeResult( $res );
1016                 return $obj;
1017
1018         }
1019
1020         /**
1021          * Estimate rows in dataset
1022          * Returns estimated count, based on EXPLAIN output
1023          * Takes same arguments as Database::select()
1024          */
1025
1026         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1027                 $options['EXPLAIN']=true;
1028                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1029                 if ( $res === false )
1030                         return false;
1031                 if (!$this->numRows($res)) {
1032                         $this->freeResult($res);
1033                         return 0;
1034                 }
1035
1036                 $rows=1;
1037
1038                 while( $plan = $this->fetchObject( $res ) ) {
1039                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1040                 }
1041
1042                 $this->freeResult($res);
1043                 return $rows;
1044         }
1045
1046
1047         /**
1048          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1049          * It's only slightly flawed. Don't use for anything important.
1050          *
1051          * @param string $sql A SQL Query
1052          * @static
1053          */
1054         static function generalizeSQL( $sql ) {
1055                 # This does the same as the regexp below would do, but in such a way
1056                 # as to avoid crashing php on some large strings.
1057                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1058
1059                 $sql = str_replace ( "\\\\", '', $sql);
1060                 $sql = str_replace ( "\\'", '', $sql);
1061                 $sql = str_replace ( "\\\"", '', $sql);
1062                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1063                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1064
1065                 # All newlines, tabs, etc replaced by single space
1066                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1067
1068                 # All numbers => N
1069                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1070
1071                 return $sql;
1072         }
1073
1074         /**
1075          * Determines whether a field exists in a table
1076          * Usually aborts on failure
1077          * If errors are explicitly ignored, returns NULL on failure
1078          */
1079         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1080                 $table = $this->tableName( $table );
1081                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1082                 if ( !$res ) {
1083                         return NULL;
1084                 }
1085
1086                 $found = false;
1087
1088                 while ( $row = $this->fetchObject( $res ) ) {
1089                         if ( $row->Field == $field ) {
1090                                 $found = true;
1091                                 break;
1092                         }
1093                 }
1094                 return $found;
1095         }
1096
1097         /**
1098          * Determines whether an index exists
1099          * Usually aborts on failure
1100          * If errors are explicitly ignored, returns NULL on failure
1101          */
1102         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1103                 $info = $this->indexInfo( $table, $index, $fname );
1104                 if ( is_null( $info ) ) {
1105                         return NULL;
1106                 } else {
1107                         return $info !== false;
1108                 }
1109         }
1110
1111
1112         /**
1113          * Get information about an index into an object
1114          * Returns false if the index does not exist
1115          */
1116         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1117                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1118                 # SHOW INDEX should work for 3.x and up:
1119                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1120                 $table = $this->tableName( $table );
1121                 $sql = 'SHOW INDEX FROM '.$table;
1122                 $res = $this->query( $sql, $fname );
1123                 if ( !$res ) {
1124                         return NULL;
1125                 }
1126
1127                 $result = array();
1128                 while ( $row = $this->fetchObject( $res ) ) {
1129                         if ( $row->Key_name == $index ) {
1130                                 $result[] = $row;
1131                         }
1132                 }
1133                 $this->freeResult($res);
1134
1135                 return empty($result) ? false : $result;
1136         }
1137
1138         /**
1139          * Query whether a given table exists
1140          */
1141         function tableExists( $table ) {
1142                 $table = $this->tableName( $table );
1143                 $old = $this->ignoreErrors( true );
1144                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1145                 $this->ignoreErrors( $old );
1146                 if( $res ) {
1147                         $this->freeResult( $res );
1148                         return true;
1149                 } else {
1150                         return false;
1151                 }
1152         }
1153
1154         /**
1155          * mysql_fetch_field() wrapper
1156          * Returns false if the field doesn't exist
1157          *
1158          * @param $table
1159          * @param $field
1160          */
1161         function fieldInfo( $table, $field ) {
1162                 $table = $this->tableName( $table );
1163                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1164                 $n = mysql_num_fields( $res->result );
1165                 for( $i = 0; $i < $n; $i++ ) {
1166                         $meta = mysql_fetch_field( $res->result, $i );
1167                         if( $field == $meta->name ) {
1168                                 return new MySQLField($meta);
1169                         }
1170                 }
1171                 return false;
1172         }
1173
1174         /**
1175          * mysql_field_type() wrapper
1176          */
1177         function fieldType( $res, $index ) {
1178                 if ( $res instanceof ResultWrapper ) {
1179                         $res = $res->result;
1180                 }
1181                 return mysql_field_type( $res, $index );
1182         }
1183
1184         /**
1185          * Determines if a given index is unique
1186          */
1187         function indexUnique( $table, $index ) {
1188                 $indexInfo = $this->indexInfo( $table, $index );
1189                 if ( !$indexInfo ) {
1190                         return NULL;
1191                 }
1192                 return !$indexInfo[0]->Non_unique;
1193         }
1194
1195         /**
1196          * INSERT wrapper, inserts an array into a table
1197          *
1198          * $a may be a single associative array, or an array of these with numeric keys, for
1199          * multi-row insert.
1200          *
1201          * Usually aborts on failure
1202          * If errors are explicitly ignored, returns success
1203          */
1204         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1205                 # No rows to insert, easy just return now
1206                 if ( !count( $a ) ) {
1207                         return true;
1208                 }
1209
1210                 $table = $this->tableName( $table );
1211                 if ( !is_array( $options ) ) {
1212                         $options = array( $options );
1213                 }
1214                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1215                         $multi = true;
1216                         $keys = array_keys( $a[0] );
1217                 } else {
1218                         $multi = false;
1219                         $keys = array_keys( $a );
1220                 }
1221
1222                 $sql = 'INSERT ' . implode( ' ', $options ) .
1223                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1224
1225                 if ( $multi ) {
1226                         $first = true;
1227                         foreach ( $a as $row ) {
1228                                 if ( $first ) {
1229                                         $first = false;
1230                                 } else {
1231                                         $sql .= ',';
1232                                 }
1233                                 $sql .= '(' . $this->makeList( $row ) . ')';
1234                         }
1235                 } else {
1236                         $sql .= '(' . $this->makeList( $a ) . ')';
1237                 }
1238                 return (bool)$this->query( $sql, $fname );
1239         }
1240
1241         /**
1242          * Make UPDATE options for the Database::update function
1243          *
1244          * @private
1245          * @param array $options The options passed to Database::update
1246          * @return string
1247          */
1248         function makeUpdateOptions( $options ) {
1249                 if( !is_array( $options ) ) {
1250                         $options = array( $options );
1251                 }
1252                 $opts = array();
1253                 if ( in_array( 'LOW_PRIORITY', $options ) )
1254                         $opts[] = $this->lowPriorityOption();
1255                 if ( in_array( 'IGNORE', $options ) )
1256                         $opts[] = 'IGNORE';
1257                 return implode(' ', $opts);
1258         }
1259
1260         /**
1261          * UPDATE wrapper, takes a condition array and a SET array
1262          *
1263          * @param string $table  The table to UPDATE
1264          * @param array  $values An array of values to SET
1265          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1266          * @param string $fname  The Class::Function calling this function
1267          *                       (for the log)
1268          * @param array  $options An array of UPDATE options, can be one or
1269          *                        more of IGNORE, LOW_PRIORITY
1270          * @return bool
1271          */
1272         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1273                 $table = $this->tableName( $table );
1274                 $opts = $this->makeUpdateOptions( $options );
1275                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1276                 if ( $conds != '*' ) {
1277                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1278                 }
1279                 return $this->query( $sql, $fname );
1280         }
1281
1282         /**
1283          * Makes an encoded list of strings from an array
1284          * $mode:
1285          *        LIST_COMMA         - comma separated, no field names
1286          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1287          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1288          *        LIST_SET           - comma separated with field names, like a SET clause
1289          *        LIST_NAMES         - comma separated field names
1290          */
1291         function makeList( $a, $mode = LIST_COMMA ) {
1292                 if ( !is_array( $a ) ) {
1293                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1294                 }
1295
1296                 $first = true;
1297                 $list = '';
1298                 foreach ( $a as $field => $value ) {
1299                         if ( !$first ) {
1300                                 if ( $mode == LIST_AND ) {
1301                                         $list .= ' AND ';
1302                                 } elseif($mode == LIST_OR) {
1303                                         $list .= ' OR ';
1304                                 } else {
1305                                         $list .= ',';
1306                                 }
1307                         } else {
1308                                 $first = false;
1309                         }
1310                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1311                                 $list .= "($value)";
1312                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1313                                 $list .= "$value";
1314                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1315                                 if( count( $value ) == 0 ) {
1316                                         throw new MWException( __METHOD__.': empty input' );
1317                                 } elseif( count( $value ) == 1 ) {
1318                                         // Special-case single values, as IN isn't terribly efficient
1319                                         // Don't necessarily assume the single key is 0; we don't
1320                                         // enforce linear numeric ordering on other arrays here.
1321                                         $value = array_values( $value );
1322                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1323                                 } else {
1324                                         $list .= $field." IN (".$this->makeList($value).") ";
1325                                 }
1326                         } elseif( is_null($value) ) {
1327                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1328                                         $list .= "$field IS ";
1329                                 } elseif ( $mode == LIST_SET ) {
1330                                         $list .= "$field = ";
1331                                 }
1332                                 $list .= 'NULL';
1333                         } else {
1334                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1335                                         $list .= "$field = ";
1336                                 }
1337                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1338                         }
1339                 }
1340                 return $list;
1341         }
1342
1343         /**
1344          * Change the current database
1345          */
1346         function selectDB( $db ) {
1347                 $this->mDBname = $db;
1348                 return mysql_select_db( $db, $this->mConn );
1349         }
1350
1351         /**
1352          * Get the current DB name
1353          */
1354         function getDBname() {
1355                 return $this->mDBname;
1356         }
1357
1358         /**
1359          * Get the server hostname or IP address
1360          */
1361         function getServer() {
1362                 return $this->mServer;
1363         }
1364
1365         /**
1366          * Format a table name ready for use in constructing an SQL query
1367          *
1368          * This does two important things: it quotes the table names to clean them up,
1369          * and it adds a table prefix if only given a table name with no quotes.
1370          *
1371          * All functions of this object which require a table name call this function
1372          * themselves. Pass the canonical name to such functions. This is only needed
1373          * when calling query() directly.
1374          *
1375          * @param string $name database table name
1376          * @return string full database name
1377          */
1378         function tableName( $name ) {
1379                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1380                 # Skip the entire process when we have a string quoted on both ends.
1381                 # Note that we check the end so that we will still quote any use of
1382                 # use of `database`.table. But won't break things if someone wants
1383                 # to query a database table with a dot in the name.
1384                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) return $name;
1385
1386                 # Lets test for any bits of text that should never show up in a table
1387                 # name. Basically anything like JOIN or ON which are actually part of
1388                 # SQL queries, but may end up inside of the table value to combine
1389                 # sql. Such as how the API is doing.
1390                 # Note that we use a whitespace test rather than a \b test to avoid
1391                 # any remote case where a word like on may be inside of a table name
1392                 # surrounded by symbols which may be considered word breaks.
1393                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) return $name;
1394
1395                 # Split database and table into proper variables.
1396                 # We reverse the explode so that database.table and table both output
1397                 # the correct table.
1398                 @list( $table, $database ) = array_reverse( explode( '.', $name, 2 ) );
1399                 $prefix = $this->mTablePrefix; # Default prefix
1400
1401                 # A database name has been specified in input. Quote the table name
1402                 # because we don't want any prefixes added.
1403                 if( isset($database) ) $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1404
1405                 # Note that we use the long format because php will complain in in_array if
1406                 # the input is not an array, and will complain in is_array if it is not set.
1407                 if( !isset( $database ) # Don't use shared database if pre selected.
1408                  && isset( $wgSharedDB ) # We have a shared database
1409                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1410                  && isset( $wgSharedTables )
1411                  && is_array( $wgSharedTables )
1412                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1413                         $database = $wgSharedDB;
1414                         $prefix   = isset( $wgSharedprefix ) ? $wgSharedprefix : $prefix;
1415                 }
1416
1417                 # Quote the $database and $table and apply the prefix if not quoted.
1418                 if( isset($database) ) $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1419                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1420
1421                 # Merge our database and table into our final table name.
1422                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1423
1424                 # We're finished, return.
1425                 return $tableName;
1426         }
1427
1428         /**
1429          * Fetch a number of table names into an array
1430          * This is handy when you need to construct SQL for joins
1431          *
1432          * Example:
1433          * extract($dbr->tableNames('user','watchlist'));
1434          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1435          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1436          */
1437         public function tableNames() {
1438                 $inArray = func_get_args();
1439                 $retVal = array();
1440                 foreach ( $inArray as $name ) {
1441                         $retVal[$name] = $this->tableName( $name );
1442                 }
1443                 return $retVal;
1444         }
1445
1446         /**
1447          * Fetch a number of table names into an zero-indexed numerical array
1448          * This is handy when you need to construct SQL for joins
1449          *
1450          * Example:
1451          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1452          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1453          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1454          */
1455         public function tableNamesN() {
1456                 $inArray = func_get_args();
1457                 $retVal = array();
1458                 foreach ( $inArray as $name ) {
1459                         $retVal[] = $this->tableName( $name );
1460                 }
1461                 return $retVal;
1462         }
1463
1464         /**
1465          * @private
1466          */
1467         function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1468                 $ret = array();
1469                 $retJOIN = array();
1470                 $use_index_safe = is_array($use_index) ? $use_index : array();
1471                 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1472                 foreach ( $tables as $table ) {
1473                         // Is there a JOIN and INDEX clause for this table?
1474                         if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1475                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1476                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1477                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1478                                 $retJOIN[] = $tableClause;
1479                         // Is there an INDEX clause?
1480                         } else if ( isset($use_index_safe[$table]) ) {
1481                                 $tableClause = $this->tableName( $table );
1482                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1483                                 $ret[] = $tableClause;
1484                         // Is there a JOIN clause?
1485                         } else if ( isset($join_conds_safe[$table]) ) {
1486                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1487                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1488                                 $retJOIN[] = $tableClause;
1489                         } else {
1490                                 $tableClause = $this->tableName( $table );
1491                                 $ret[] = $tableClause;
1492                         }
1493                 }
1494                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1495                 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1496                 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1497                 // Compile our final table clause
1498                 return implode(' ',array($straightJoins,$otherJoins) );
1499         }
1500
1501         /**
1502          * Wrapper for addslashes()
1503          * @param string $s String to be slashed.
1504          * @return string slashed string.
1505          */
1506         function strencode( $s ) {
1507                 return mysql_real_escape_string( $s, $this->mConn );
1508         }
1509
1510         /**
1511          * If it's a string, adds quotes and backslashes
1512          * Otherwise returns as-is
1513          */
1514         function addQuotes( $s ) {
1515                 if ( is_null( $s ) ) {
1516                         return 'NULL';
1517                 } else {
1518                         # This will also quote numeric values. This should be harmless,
1519                         # and protects against weird problems that occur when they really
1520                         # _are_ strings such as article titles and string->number->string
1521                         # conversion is not 1:1.
1522                         return "'" . $this->strencode( $s ) . "'";
1523                 }
1524         }
1525
1526         /**
1527          * Escape string for safe LIKE usage
1528          */
1529         function escapeLike( $s ) {
1530                 $s=$this->strencode( $s );
1531                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1532                 return $s;
1533         }
1534
1535         /**
1536          * Returns an appropriately quoted sequence value for inserting a new row.
1537          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1538          * subclass will return an integer, and save the value for insertId()
1539          */
1540         function nextSequenceValue( $seqName ) {
1541                 return NULL;
1542         }
1543
1544         /**
1545          * USE INDEX clause
1546          * PostgreSQL doesn't have them and returns ""
1547          */
1548         function useIndexClause( $index ) {
1549                 return "FORCE INDEX ($index)";
1550         }
1551
1552         /**
1553          * REPLACE query wrapper
1554          * PostgreSQL simulates this with a DELETE followed by INSERT
1555          * $row is the row to insert, an associative array
1556          * $uniqueIndexes is an array of indexes. Each element may be either a
1557          * field name or an array of field names
1558          *
1559          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1560          * However if you do this, you run the risk of encountering errors which wouldn't have
1561          * occurred in MySQL
1562          *
1563          * @todo migrate comment to phodocumentor format
1564          */
1565         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1566                 $table = $this->tableName( $table );
1567
1568                 # Single row case
1569                 if ( !is_array( reset( $rows ) ) ) {
1570                         $rows = array( $rows );
1571                 }
1572
1573                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1574                 $first = true;
1575                 foreach ( $rows as $row ) {
1576                         if ( $first ) {
1577                                 $first = false;
1578                         } else {
1579                                 $sql .= ',';
1580                         }
1581                         $sql .= '(' . $this->makeList( $row ) . ')';
1582                 }
1583                 return $this->query( $sql, $fname );
1584         }
1585
1586         /**
1587          * DELETE where the condition is a join
1588          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1589          *
1590          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1591          * join condition matches, set $conds='*'
1592          *
1593          * DO NOT put the join condition in $conds
1594          *
1595          * @param string $delTable The table to delete from.
1596          * @param string $joinTable The other table.
1597          * @param string $delVar The variable to join on, in the first table.
1598          * @param string $joinVar The variable to join on, in the second table.
1599          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1600          */
1601         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1602                 if ( !$conds ) {
1603                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1604                 }
1605
1606                 $delTable = $this->tableName( $delTable );
1607                 $joinTable = $this->tableName( $joinTable );
1608                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1609                 if ( $conds != '*' ) {
1610                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1611                 }
1612
1613                 return $this->query( $sql, $fname );
1614         }
1615
1616         /**
1617          * Returns the size of a text field, or -1 for "unlimited"
1618          */
1619         function textFieldSize( $table, $field ) {
1620                 $table = $this->tableName( $table );
1621                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1622                 $res = $this->query( $sql, 'Database::textFieldSize' );
1623                 $row = $this->fetchObject( $res );
1624                 $this->freeResult( $res );
1625
1626                 $m = array();
1627                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1628                         $size = $m[1];
1629                 } else {
1630                         $size = -1;
1631                 }
1632                 return $size;
1633         }
1634
1635         /**
1636          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1637          */
1638         function lowPriorityOption() {
1639                 return 'LOW_PRIORITY';
1640         }
1641
1642         /**
1643          * DELETE query wrapper
1644          *
1645          * Use $conds == "*" to delete all rows
1646          */
1647         function delete( $table, $conds, $fname = 'Database::delete' ) {
1648                 if ( !$conds ) {
1649                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1650                 }
1651                 $table = $this->tableName( $table );
1652                 $sql = "DELETE FROM $table";
1653                 if ( $conds != '*' ) {
1654                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1655                 }
1656                 return $this->query( $sql, $fname );
1657         }
1658
1659         /**
1660          * INSERT SELECT wrapper
1661          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1662          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1663          * $conds may be "*" to copy the whole table
1664          * srcTable may be an array of tables.
1665          */
1666         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1667                 $insertOptions = array(), $selectOptions = array() )
1668         {
1669                 $destTable = $this->tableName( $destTable );
1670                 if ( is_array( $insertOptions ) ) {
1671                         $insertOptions = implode( ' ', $insertOptions );
1672                 }
1673                 if( !is_array( $selectOptions ) ) {
1674                         $selectOptions = array( $selectOptions );
1675                 }
1676                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1677                 if( is_array( $srcTable ) ) {
1678                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1679                 } else {
1680                         $srcTable = $this->tableName( $srcTable );
1681                 }
1682                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1683                         " SELECT $startOpts " . implode( ',', $varMap ) .
1684                         " FROM $srcTable $useIndex ";
1685                 if ( $conds != '*' ) {
1686                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1687                 }
1688                 $sql .= " $tailOpts";
1689                 return $this->query( $sql, $fname );
1690         }
1691
1692         /**
1693          * Construct a LIMIT query with optional offset
1694          * This is used for query pages
1695          * $sql string SQL query we will append the limit too
1696          * $limit integer the SQL limit
1697          * $offset integer the SQL offset (default false)
1698          */
1699         function limitResult($sql, $limit, $offset=false) {
1700                 if( !is_numeric($limit) ) {
1701                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1702                 }
1703                 return "$sql LIMIT "
1704                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1705                                 . "{$limit} ";
1706         }
1707         function limitResultForUpdate($sql, $num) {
1708                 return $this->limitResult($sql, $num, 0);
1709         }
1710
1711         /**
1712          * Returns an SQL expression for a simple conditional.
1713          * Uses IF on MySQL.
1714          *
1715          * @param string $cond SQL expression which will result in a boolean value
1716          * @param string $trueVal SQL expression to return if true
1717          * @param string $falseVal SQL expression to return if false
1718          * @return string SQL fragment
1719          */
1720         function conditional( $cond, $trueVal, $falseVal ) {
1721                 return " IF($cond, $trueVal, $falseVal) ";
1722         }
1723
1724         /**
1725          * Returns a comand for str_replace function in SQL query.
1726          * Uses REPLACE() in MySQL
1727          *
1728          * @param string $orig String or column to modify
1729          * @param string $old String or column to seek
1730          * @param string $new String or column to replace with
1731          */
1732         function strreplace( $orig, $old, $new ) {
1733                 return "REPLACE({$orig}, {$old}, {$new})";
1734         }
1735
1736         /**
1737          * Determines if the last failure was due to a deadlock
1738          */
1739         function wasDeadlock() {
1740                 return $this->lastErrno() == 1213;
1741         }
1742
1743         /**
1744          * Perform a deadlock-prone transaction.
1745          *
1746          * This function invokes a callback function to perform a set of write
1747          * queries. If a deadlock occurs during the processing, the transaction
1748          * will be rolled back and the callback function will be called again.
1749          *
1750          * Usage:
1751          *   $dbw->deadlockLoop( callback, ... );
1752          *
1753          * Extra arguments are passed through to the specified callback function.
1754          *
1755          * Returns whatever the callback function returned on its successful,
1756          * iteration, or false on error, for example if the retry limit was
1757          * reached.
1758          */
1759         function deadlockLoop() {
1760                 $myFname = 'Database::deadlockLoop';
1761
1762                 $this->begin();
1763                 $args = func_get_args();
1764                 $function = array_shift( $args );
1765                 $oldIgnore = $this->ignoreErrors( true );
1766                 $tries = DEADLOCK_TRIES;
1767                 if ( is_array( $function ) ) {
1768                         $fname = $function[0];
1769                 } else {
1770                         $fname = $function;
1771                 }
1772                 do {
1773                         $retVal = call_user_func_array( $function, $args );
1774                         $error = $this->lastError();
1775                         $errno = $this->lastErrno();
1776                         $sql = $this->lastQuery();
1777
1778                         if ( $errno ) {
1779                                 if ( $this->wasDeadlock() ) {
1780                                         # Retry
1781                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1782                                 } else {
1783                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1784                                 }
1785                         }
1786                 } while( $this->wasDeadlock() && --$tries > 0 );
1787                 $this->ignoreErrors( $oldIgnore );
1788                 if ( $tries <= 0 ) {
1789                         $this->query( 'ROLLBACK', $myFname );
1790                         $this->reportQueryError( $error, $errno, $sql, $fname );
1791                         return false;
1792                 } else {
1793                         $this->query( 'COMMIT', $myFname );
1794                         return $retVal;
1795                 }
1796         }
1797
1798         /**
1799          * Do a SELECT MASTER_POS_WAIT()
1800          *
1801          * @param string $file the binlog file
1802          * @param string $pos the binlog position
1803          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1804          */
1805         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1806                 $fname = 'Database::masterPosWait';
1807                 wfProfileIn( $fname );
1808
1809                 # Commit any open transactions
1810                 if ( $this->mTrxLevel ) {
1811                         $this->immediateCommit();
1812                 }
1813
1814                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1815                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1816                         if ( $wait > $timeout * 1e6 ) {
1817                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1818                                 wfProfileOut( $fname );
1819                                 return -1;
1820                         } elseif ( $wait > 0 ) {
1821                                 wfDebug( "Fake slave waiting $wait us\n" );
1822                                 usleep( $wait );
1823                                 wfProfileOut( $fname );
1824                                 return 1;
1825                         } else {
1826                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1827                                 wfProfileOut( $fname );
1828                                 return 0;
1829                         }
1830                 }
1831
1832                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1833                 $encFile = $this->addQuotes( $pos->file );
1834                 $encPos = intval( $pos->pos );
1835                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1836                 $res = $this->doQuery( $sql );
1837                 if ( $res && $row = $this->fetchRow( $res ) ) {
1838                         $this->freeResult( $res );
1839                         wfProfileOut( $fname );
1840                         return $row[0];
1841                 } else {
1842                         wfProfileOut( $fname );
1843                         return false;
1844                 }
1845         }
1846
1847         /**
1848          * Get the position of the master from SHOW SLAVE STATUS
1849          */
1850         function getSlavePos() {
1851                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1852                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1853                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1854                         return $pos;
1855                 }
1856                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1857                 $row = $this->fetchObject( $res );
1858                 if ( $row ) {
1859                         return new MySQLMasterPos( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1860                 } else {
1861                         return false;
1862                 }
1863         }
1864
1865         /**
1866          * Get the position of the master from SHOW MASTER STATUS
1867          */
1868         function getMasterPos() {
1869                 if ( $this->mFakeMaster ) {
1870                         return new MySQLMasterPos( 'fake', microtime( true ) );
1871                 }
1872                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1873                 $row = $this->fetchObject( $res );
1874                 if ( $row ) {
1875                         return new MySQLMasterPos( $row->File, $row->Position );
1876                 } else {
1877                         return false;
1878                 }
1879         }
1880
1881         /**
1882          * Begin a transaction, committing any previously open transaction
1883          */
1884         function begin( $fname = 'Database::begin' ) {
1885                 $this->query( 'BEGIN', $fname );
1886                 $this->mTrxLevel = 1;
1887         }
1888
1889         /**
1890          * End a transaction
1891          */
1892         function commit( $fname = 'Database::commit' ) {
1893                 $this->query( 'COMMIT', $fname );
1894                 $this->mTrxLevel = 0;
1895         }
1896
1897         /**
1898          * Rollback a transaction.
1899          * No-op on non-transactional databases.
1900          */
1901         function rollback( $fname = 'Database::rollback' ) {
1902                 $this->query( 'ROLLBACK', $fname, true );
1903                 $this->mTrxLevel = 0;
1904         }
1905
1906         /**
1907          * Begin a transaction, committing any previously open transaction
1908          * @deprecated use begin()
1909          */
1910         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1911                 $this->begin();
1912         }
1913
1914         /**
1915          * Commit transaction, if one is open
1916          * @deprecated use commit()
1917          */
1918         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1919                 $this->commit();
1920         }
1921
1922         /**
1923          * Return MW-style timestamp used for MySQL schema
1924          */
1925         function timestamp( $ts=0 ) {
1926                 return wfTimestamp(TS_MW,$ts);
1927         }
1928
1929         /**
1930          * Local database timestamp format or null
1931          */
1932         function timestampOrNull( $ts = null ) {
1933                 if( is_null( $ts ) ) {
1934                         return null;
1935                 } else {
1936                         return $this->timestamp( $ts );
1937                 }
1938         }
1939
1940         /**
1941          * @todo document
1942          */
1943         function resultObject( $result ) {
1944                 if( empty( $result ) ) {
1945                         return false;
1946                 } elseif ( $result instanceof ResultWrapper ) {
1947                         return $result;
1948                 } elseif ( $result === true ) {
1949                         // Successful write query
1950                         return $result;
1951                 } else {
1952                         return new ResultWrapper( $this, $result );
1953                 }
1954         }
1955
1956         /**
1957          * Return aggregated value alias
1958          */
1959         function aggregateValue ($valuedata,$valuename='value') {
1960                 return $valuename;
1961         }
1962
1963         /**
1964          * @return string wikitext of a link to the server software's web site
1965          */
1966         function getSoftwareLink() {
1967                 return "[http://www.mysql.com/ MySQL]";
1968         }
1969
1970         /**
1971          * @return string Version information from the database
1972          */
1973         function getServerVersion() {
1974                 return mysql_get_server_info( $this->mConn );
1975         }
1976
1977         /**
1978          * Ping the server and try to reconnect if it there is no connection
1979          */
1980         function ping() {
1981                 if( !function_exists( 'mysql_ping' ) ) {
1982                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1983                         return true;
1984                 }
1985                 $ping = mysql_ping( $this->mConn );
1986                 if ( $ping ) {
1987                         return true;
1988                 }
1989
1990                 // Need to reconnect manually in MySQL client 5.0.13+
1991                 if ( version_compare( mysql_get_client_info(), '5.0.13', '>=' ) ) {
1992                         mysql_close( $this->mConn );
1993                         $this->mOpened = false;
1994                         $this->mConn = false;
1995                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
1996                         return true;
1997                 }
1998                 return false;
1999         }
2000
2001         /**
2002          * Get slave lag.
2003          * At the moment, this will only work if the DB user has the PROCESS privilege
2004          */
2005         function getLag() {
2006                 if ( !is_null( $this->mFakeSlaveLag ) ) {
2007                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
2008                         return $this->mFakeSlaveLag;
2009                 }
2010                 $res = $this->query( 'SHOW PROCESSLIST' );
2011                 # Find slave SQL thread
2012                 while ( $row = $this->fetchObject( $res ) ) {
2013                         /* This should work for most situations - when default db
2014                          * for thread is not specified, it had no events executed,
2015                          * and therefore it doesn't know yet how lagged it is.
2016                          *
2017                          * Relay log I/O thread does not select databases.
2018                          */
2019                         if ( $row->User == 'system user' &&
2020                                 $row->State != 'Waiting for master to send event' &&
2021                                 $row->State != 'Connecting to master' &&
2022                                 $row->State != 'Queueing master event to the relay log' &&
2023                                 $row->State != 'Waiting for master update' &&
2024                                 $row->State != 'Requesting binlog dump'
2025                                 ) {
2026                                 # This is it, return the time (except -ve)
2027                                 if ( $row->Time > 0x7fffffff ) {
2028                                         return false;
2029                                 } else {
2030                                         return $row->Time;
2031                                 }
2032                         }
2033                 }
2034                 return false;
2035         }
2036
2037         /**
2038          * Get status information from SHOW STATUS in an associative array
2039          */
2040         function getStatus($which="%") {
2041                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2042                 $status = array();
2043                 while ( $row = $this->fetchObject( $res ) ) {
2044                         $status[$row->Variable_name] = $row->Value;
2045                 }
2046                 return $status;
2047         }
2048
2049         /**
2050          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2051          */
2052         function maxListLen() {
2053                 return 0;
2054         }
2055
2056         function encodeBlob($b) {
2057                 return $b;
2058         }
2059
2060         function decodeBlob($b) {
2061                 return $b;
2062         }
2063
2064         /**
2065          * Override database's default connection timeout.
2066          * May be useful for very long batch queries such as
2067          * full-wiki dumps, where a single query reads out
2068          * over hours or days.
2069          * @param int $timeout in seconds
2070          */
2071         public function setTimeout( $timeout ) {
2072                 $this->query( "SET net_read_timeout=$timeout" );
2073                 $this->query( "SET net_write_timeout=$timeout" );
2074         }
2075
2076         /**
2077          * Read and execute SQL commands from a file.
2078          * Returns true on success, error string on failure
2079          * @param string $filename File name to open
2080          * @param callback $lineCallback Optional function called before reading each line
2081          * @param callback $resultCallback Optional function called for each MySQL result
2082          */
2083         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2084                 $fp = fopen( $filename, 'r' );
2085                 if ( false === $fp ) {
2086                         return "Could not open \"{$filename}\".\n";
2087                 }
2088                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2089                 fclose( $fp );
2090                 return $error;
2091         }
2092
2093         /**
2094          * Read and execute commands from an open file handle
2095          * Returns true on success, error string on failure
2096          * @param string $fp File handle
2097          * @param callback $lineCallback Optional function called before reading each line
2098          * @param callback $resultCallback Optional function called for each MySQL result
2099          */
2100         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2101                 $cmd = "";
2102                 $done = false;
2103                 $dollarquote = false;
2104
2105                 while ( ! feof( $fp ) ) {
2106                         if ( $lineCallback ) {
2107                                 call_user_func( $lineCallback );
2108                         }
2109                         $line = trim( fgets( $fp, 1024 ) );
2110                         $sl = strlen( $line ) - 1;
2111
2112                         if ( $sl < 0 ) { continue; }
2113                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2114
2115                         ## Allow dollar quoting for function declarations
2116                         if (substr($line,0,4) == '$mw$') {
2117                                 if ($dollarquote) {
2118                                         $dollarquote = false;
2119                                         $done = true;
2120                                 }
2121                                 else {
2122                                         $dollarquote = true;
2123                                 }
2124                         }
2125                         else if (!$dollarquote) {
2126                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2127                                         $done = true;
2128                                         $line = substr( $line, 0, $sl );
2129                                 }
2130                         }
2131
2132                         if ( '' != $cmd ) { $cmd .= ' '; }
2133                         $cmd .= "$line\n";
2134
2135                         if ( $done ) {
2136                                 $cmd = str_replace(';;', ";", $cmd);
2137                                 $cmd = $this->replaceVars( $cmd );
2138                                 $res = $this->query( $cmd, __METHOD__, true );
2139                                 if ( $resultCallback ) {
2140                                         call_user_func( $resultCallback, $res );
2141                                 }
2142
2143                                 if ( false === $res ) {
2144                                         $err = $this->lastError();
2145                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2146                                 }
2147
2148                                 $cmd = '';
2149                                 $done = false;
2150                         }
2151                 }
2152                 return true;
2153         }
2154
2155
2156         /**
2157          * Replace variables in sourced SQL
2158          */
2159         protected function replaceVars( $ins ) {
2160                 $varnames = array(
2161                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2162                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2163                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2164                 );
2165
2166                 // Ordinary variables
2167                 foreach ( $varnames as $var ) {
2168                         if( isset( $GLOBALS[$var] ) ) {
2169                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2170                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2171                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2172                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2173                         }
2174                 }
2175
2176                 // Table prefixes
2177                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
2178                         array( &$this, 'tableNameCallback' ), $ins );
2179                 return $ins;
2180         }
2181
2182         /**
2183          * Table name callback
2184          * @private
2185          */
2186         protected function tableNameCallback( $matches ) {
2187                 return $this->tableName( $matches[1] );
2188         }
2189
2190         /*
2191          * Build a concatenation list to feed into a SQL query
2192         */
2193         function buildConcat( $stringList ) {
2194                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2195         }
2196
2197 }
2198
2199 /**
2200  * Database abstraction object for mySQL
2201  * Inherit all methods and properties of Database::Database()
2202  *
2203  * @addtogroup Database
2204  * @see Database
2205  */
2206 class DatabaseMysql extends Database {
2207         # Inherit all
2208 }
2209
2210 /******************************************************************************
2211  * Utility classes
2212  *****************************************************************************/
2213
2214 /**
2215  * Utility class.
2216  * @addtogroup Database
2217  */
2218 class DBObject {
2219         public $mData;
2220
2221         function DBObject($data) {
2222                 $this->mData = $data;
2223         }
2224
2225         function isLOB() {
2226                 return false;
2227         }
2228
2229         function data() {
2230                 return $this->mData;
2231         }
2232 }
2233
2234 /**
2235  * Utility class
2236  * @addtogroup Database
2237  *
2238  * This allows us to distinguish a blob from a normal string and an array of strings
2239  */
2240 class Blob {
2241         private $mData;
2242         function __construct($data) {
2243                 $this->mData = $data;
2244         }
2245         function fetch() {
2246                 return $this->mData;
2247         }
2248 }
2249
2250 /**
2251  * Utility class.
2252  * @addtogroup Database
2253  */
2254 class MySQLField {
2255         private $name, $tablename, $default, $max_length, $nullable,
2256                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2257         function __construct ($info) {
2258                 $this->name = $info->name;
2259                 $this->tablename = $info->table;
2260                 $this->default = $info->def;
2261                 $this->max_length = $info->max_length;
2262                 $this->nullable = !$info->not_null;
2263                 $this->is_pk = $info->primary_key;
2264                 $this->is_unique = $info->unique_key;
2265                 $this->is_multiple = $info->multiple_key;
2266                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2267                 $this->type = $info->type;
2268         }
2269
2270         function name() {
2271                 return $this->name;
2272         }
2273
2274         function tableName() {
2275                 return $this->tableName;
2276         }
2277
2278         function defaultValue() {
2279                 return $this->default;
2280         }
2281
2282         function maxLength() {
2283                 return $this->max_length;
2284         }
2285
2286         function nullable() {
2287                 return $this->nullable;
2288         }
2289
2290         function isKey() {
2291                 return $this->is_key;
2292         }
2293
2294         function isMultipleKey() {
2295                 return $this->is_multiple;
2296         }
2297
2298         function type() {
2299                 return $this->type;
2300         }
2301 }
2302
2303 /******************************************************************************
2304  * Error classes
2305  *****************************************************************************/
2306
2307 /**
2308  * Database error base class
2309  * @addtogroup Database
2310  */
2311 class DBError extends MWException {
2312         public $db;
2313
2314         /**
2315          * Construct a database error
2316          * @param Database $db The database object which threw the error
2317          * @param string $error A simple error message to be used for debugging
2318          */
2319         function __construct( Database &$db, $error ) {
2320                 $this->db =& $db;
2321                 parent::__construct( $error );
2322         }
2323 }
2324
2325 /**
2326  * @addtogroup Database
2327  */
2328 class DBConnectionError extends DBError {
2329         public $error;
2330
2331         function __construct( Database &$db, $error = 'unknown error' ) {
2332                 $msg = 'DB connection error';
2333                 if ( trim( $error ) != '' ) {
2334                         $msg .= ": $error";
2335                 }
2336                 $this->error = $error;
2337                 parent::__construct( $db, $msg );
2338         }
2339
2340         function useOutputPage() {
2341                 // Not likely to work
2342                 return false;
2343         }
2344
2345         function useMessageCache() {
2346                 // Not likely to work
2347                 return false;
2348         }
2349
2350         function getText() {
2351                 return $this->getMessage() . "\n";
2352         }
2353
2354         function getLogMessage() {
2355                 # Don't send to the exception log
2356                 return false;
2357         }
2358
2359         function getPageTitle() {
2360                 global $wgSitename;
2361                 return "$wgSitename has a problem";
2362         }
2363
2364         function getHTML() {
2365                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
2366                 global $wgSitename, $wgServer, $wgMessageCache;
2367
2368                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
2369                 # Hard coding strings instead.
2370
2371                 $noconnect = "<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>";
2372                 $mainpage = 'Main Page';
2373                 $searchdisabled = <<<EOT
2374 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
2375 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
2376 EOT;
2377
2378                 $googlesearch = "
2379 <!-- SiteSearch Google -->
2380 <FORM method=GET action=\"http://www.google.com/search\">
2381 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
2382 <A HREF=\"http://www.google.com/\">
2383 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
2384 border=\"0\" ALT=\"Google\"></A>
2385 </td>
2386 <td>
2387 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
2388 <INPUT type=submit name=btnG VALUE=\"Google Search\">
2389 <font size=-1>
2390 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
2391 <input type='hidden' name='ie' value='$2'>
2392 <input type='hidden' name='oe' value='$2'>
2393 </font>
2394 </td></tr></TABLE>
2395 </FORM>
2396 <!-- SiteSearch Google -->";
2397                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
2398
2399                 # No database access
2400                 if ( is_object( $wgMessageCache ) ) {
2401                         $wgMessageCache->disable();
2402                 }
2403
2404                 if ( trim( $this->error ) == '' ) {
2405                         $this->error = $this->db->getProperty('mServer');
2406                 }
2407
2408                 $text = str_replace( '$1', $this->error, $noconnect );
2409                 $text .= wfGetSiteNotice();
2410
2411                 if($wgUseFileCache) {
2412                         if($wgTitle) {
2413                                 $t =& $wgTitle;
2414                         } else {
2415                                 if($title) {
2416                                         $t = Title::newFromURL( $title );
2417                                 } elseif (@/**/$_REQUEST['search']) {
2418                                         $search = $_REQUEST['search'];
2419                                         return $searchdisabled .
2420                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
2421                                           $wgInputEncoding ), $googlesearch );
2422                                 } else {
2423                                         $t = Title::newFromText( $mainpage );
2424                                 }
2425                         }
2426
2427                         $cache = new HTMLFileCache( $t );
2428                         if( $cache->isFileCached() ) {
2429                                 // @todo, FIXME: $msg is not defined on the next line.
2430                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
2431                                         $cachederror . "</b></p>\n";
2432
2433                                 $tag = '<div id="article">';
2434                                 $text = str_replace(
2435                                         $tag,
2436                                         $tag . $msg,
2437                                         $cache->fetchPageText() );
2438                         }
2439                 }
2440
2441                 return $text;
2442         }
2443 }
2444
2445 /**
2446  * @addtogroup Database
2447  */
2448 class DBQueryError extends DBError {
2449         public $error, $errno, $sql, $fname;
2450
2451         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
2452                 $message = "A database error has occurred\n" .
2453                   "Query: $sql\n" .
2454                   "Function: $fname\n" .
2455                   "Error: $errno $error\n";
2456
2457                 parent::__construct( $db, $message );
2458                 $this->error = $error;
2459                 $this->errno = $errno;
2460                 $this->sql = $sql;
2461                 $this->fname = $fname;
2462         }
2463
2464         function getText() {
2465                 if ( $this->useMessageCache() ) {
2466                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2467                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2468                 } else {
2469                         return $this->getMessage();
2470                 }
2471         }
2472
2473         function getSQL() {
2474                 global $wgShowSQLErrors;
2475                 if( !$wgShowSQLErrors ) {
2476                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2477                 } else {
2478                         return $this->sql;
2479                 }
2480         }
2481
2482         function getLogMessage() {
2483                 # Don't send to the exception log
2484                 return false;
2485         }
2486
2487         function getPageTitle() {
2488                 return $this->msg( 'databaseerror', 'Database error' );
2489         }
2490
2491         function getHTML() {
2492                 if ( $this->useMessageCache() ) {
2493                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2494                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2495                 } else {
2496                         return nl2br( htmlspecialchars( $this->getMessage() ) );
2497                 }
2498         }
2499 }
2500
2501 /**
2502  * @addtogroup Database
2503  */
2504 class DBUnexpectedError extends DBError {}
2505
2506
2507 /**
2508  * Result wrapper for grabbing data queried by someone else
2509  * @addtogroup Database
2510  */
2511 class ResultWrapper implements Iterator {
2512         var $db, $result, $pos = 0, $currentRow = null;
2513
2514         /**
2515          * Create a new result object from a result resource and a Database object
2516          */
2517         function ResultWrapper( $database, $result ) {
2518                 $this->db = $database;
2519                 if ( $result instanceof ResultWrapper ) {
2520                         $this->result = $result->result;
2521                 } else {
2522                         $this->result = $result;
2523                 }
2524         }
2525
2526         /**
2527          * Get the number of rows in a result object
2528          */
2529         function numRows() {
2530                 return $this->db->numRows( $this->result );
2531         }
2532
2533         /**
2534          * Fetch the next row from the given result object, in object form.
2535          * Fields can be retrieved with $row->fieldname, with fields acting like
2536          * member variables.
2537          *
2538          * @param $res SQL result object as returned from Database::query(), etc.
2539          * @return MySQL row object
2540          * @throws DBUnexpectedError Thrown if the database returns an error
2541          */
2542         function fetchObject() {
2543                 return $this->db->fetchObject( $this->result );
2544         }
2545
2546         /**
2547          * Fetch the next row from the given result object, in associative array
2548          * form.  Fields are retrieved with $row['fieldname'].
2549          *
2550          * @param $res SQL result object as returned from Database::query(), etc.
2551          * @return MySQL row object
2552          * @throws DBUnexpectedError Thrown if the database returns an error
2553          */
2554         function fetchRow() {
2555                 return $this->db->fetchRow( $this->result );
2556         }
2557
2558         /**
2559          * Free a result object
2560          */
2561         function free() {
2562                 $this->db->freeResult( $this->result );
2563                 unset( $this->result );
2564                 unset( $this->db );
2565         }
2566
2567         /**
2568          * Change the position of the cursor in a result object
2569          * See mysql_data_seek()
2570          */
2571         function seek( $row ) {
2572                 $this->db->dataSeek( $this->result, $row );
2573         }
2574
2575         /*********************
2576          * Iterator functions
2577          * Note that using these in combination with the non-iterator functions
2578          * above may cause rows to be skipped or repeated.
2579          */
2580
2581         function rewind() {
2582                 if ($this->numRows()) {
2583                         $this->db->dataSeek($this->result, 0);
2584                 }
2585                 $this->pos = 0;
2586                 $this->currentRow = null;
2587         }
2588
2589         function current() {
2590                 if ( is_null( $this->currentRow ) ) {
2591                         $this->next();
2592                 }
2593                 return $this->currentRow;
2594         }
2595
2596         function key() {
2597                 return $this->pos;
2598         }
2599
2600         function next() {
2601                 $this->pos++;
2602                 $this->currentRow = $this->fetchObject();
2603                 return $this->currentRow;
2604         }
2605
2606         function valid() {
2607                 return $this->current() !== false;
2608         }
2609 }
2610
2611 class MySQLMasterPos {
2612         var $file, $pos;
2613
2614         function __construct( $file, $pos ) {
2615                 $this->file = $file;
2616                 $this->pos = $pos;
2617         }
2618
2619         function __toString() {
2620                 return "{$this->file}/{$this->pos}";
2621         }
2622 }