includes/db/Database.php

   1 <?php
   2 /**
   3  * @defgroup Database Database
   4  *
   5  * @file
   6  * @ingroup Database
   7  * This file deals with MySQL interface functions
   8  * and query specifics/optimisations
   9  */
  10
  11 /** Number of times to re-try an operation in case of deadlock */
  12 define( 'DEADLOCK_TRIES', 4 );
  13 /** Minimum time to wait before retry, in microseconds */
  14 define( 'DEADLOCK_DELAY_MIN', 500000 );
  15 /** Maximum time to wait before retry */
  16 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  17
  18 /**
  19  * Database abstraction object
  20  * @ingroup Database
  21  */
  22 class Database {
  23
  24 #------------------------------------------------------------------------------
  25 # Variables
  26 #------------------------------------------------------------------------------
  27
  28         protected $mLastQuery = '';
  29         protected $mPHPError = false;
  30
  31         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  32         protected $mOpened = false;
  33
  34         protected $mFailFunction;
  35         protected $mTablePrefix;
  36         protected $mFlags;
  37         protected $mTrxLevel = 0;
  38         protected $mErrorCount = 0;
  39         protected $mLBInfo = array();
  40         protected $mFakeSlaveLag = null, $mFakeMaster = false;
  41
  42 #------------------------------------------------------------------------------
  43 # Accessors
  44 #------------------------------------------------------------------------------
  45         # These optionally set a variable and return the previous state
  46
  47         /**
  48          * Fail function, takes a Database as a parameter
  49          * Set to false for default, 1 for ignore errors
  50          */
  51         function failFunction( $function = NULL ) {
  52                 return wfSetVar( $this->mFailFunction, $function );
  53         }
  54
  55         /**
  56          * Output page, used for reporting errors
  57          * FALSE means discard output
  58          */
  59         function setOutputPage( $out ) {
  60                 wfDeprecated( __METHOD__ );
  61         }
  62
  63         /**
  64          * Boolean, controls output of large amounts of debug information
  65          */
  66         function debug( $debug = NULL ) {
  67                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  68         }
  69
  70         /**
  71          * Turns buffering of SQL result sets on (true) or off (false).
  72          * Default is "on" and it should not be changed without good reasons.
  73          */
  74         function bufferResults( $buffer = NULL ) {
  75                 if ( is_null( $buffer ) ) {
  76                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  77                 } else {
  78                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  79                 }
  80         }
  81
  82         /**
  83          * Turns on (false) or off (true) the automatic generation and sending
  84          * of a "we're sorry, but there has been a database error" page on
  85          * database errors. Default is on (false). When turned off, the
  86          * code should use lastErrno() and lastError() to handle the
  87          * situation as appropriate.
  88          */
  89         function ignoreErrors( $ignoreErrors = NULL ) {
  90                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  91         }
  92
  93         /**
  94          * The current depth of nested transactions
  95          * @param $level Integer: , default NULL.
  96          */
  97         function trxLevel( $level = NULL ) {
  98                 return wfSetVar( $this->mTrxLevel, $level );
  99         }
 100
 101         /**
 102          * Number of errors logged, only useful when errors are ignored
 103          */
 104         function errorCount( $count = NULL ) {
 105                 return wfSetVar( $this->mErrorCount, $count );
 106         }
 107
 108         function tablePrefix( $prefix = null ) {
 109                 return wfSetVar( $this->mTablePrefix, $prefix );
 110         }
 111
 112         /**
 113          * Properties passed down from the server info array of the load balancer
 114          */
 115         function getLBInfo( $name = NULL ) {
 116                 if ( is_null( $name ) ) {
 117                         return $this->mLBInfo;
 118                 } else {
 119                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 120                                 return $this->mLBInfo[$name];
 121                         } else {
 122                                 return NULL;
 123                         }
 124                 }
 125         }
 126
 127         function setLBInfo( $name, $value = NULL ) {
 128                 if ( is_null( $value ) ) {
 129                         $this->mLBInfo = $name;
 130                 } else {
 131                         $this->mLBInfo[$name] = $value;
 132                 }
 133         }
 134
 135         /**
 136          * Set lag time in seconds for a fake slave
 137          */
 138         function setFakeSlaveLag( $lag ) {
 139                 $this->mFakeSlaveLag = $lag;
 140         }
 141
 142         /**
 143          * Make this connection a fake master
 144          */
 145         function setFakeMaster( $enabled = true ) {
 146                 $this->mFakeMaster = $enabled;
 147         }
 148
 149         /**
 150          * Returns true if this database supports (and uses) cascading deletes
 151          */
 152         function cascadingDeletes() {
 153                 return false;
 154         }
 155
 156         /**
 157          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 158          */
 159         function cleanupTriggers() {
 160                 return false;
 161         }
 162
 163         /**
 164          * Returns true if this database is strict about what can be put into an IP field.
 165          * Specifically, it uses a NULL value instead of an empty string.
 166          */
 167         function strictIPs() {
 168                 return false;
 169         }
 170
 171         /**
 172          * Returns true if this database uses timestamps rather than integers
 173         */
 174         function realTimestamps() {
 175                 return false;
 176         }
 177
 178         /**
 179          * Returns true if this database does an implicit sort when doing GROUP BY
 180          */
 181         function implicitGroupby() {
 182                 return true;
 183         }
 184
 185         /**
 186          * Returns true if this database does an implicit order by when the column has an index
 187          * For example: SELECT page_title FROM page LIMIT 1
 188          */
 189         function implicitOrderby() {
 190                 return true;
 191         }
 192
 193         /**
 194          * Returns true if this database can do a native search on IP columns
 195          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 196          */
 197         function searchableIPs() {
 198                 return false;
 199         }
 200
 201         /**
 202          * Returns true if this database can use functional indexes
 203          */
 204         function functionalIndexes() {
 205                 return false;
 206         }
 207
 208         /**
 209          * Return the last query that went through Database::query()
 210          * @return string
 211          */
 212         function lastQuery() { return $this->mLastQuery; }
 213
 214         /**
 215          * Is a connection to the database open?
 216          * @return bool
 217          */
 218         function isOpen() { return $this->mOpened; }
 219
 220         function setFlag( $flag ) {
 221                 $this->mFlags |= $flag;
 222         }
 223
 224         function clearFlag( $flag ) {
 225                 $this->mFlags &= ~$flag;
 226         }
 227
 228         function getFlag( $flag ) {
 229                 return !!($this->mFlags & $flag);
 230         }
 231
 232         /**
 233          * General read-only accessor
 234          */
 235         function getProperty( $name ) {
 236                 return $this->$name;
 237         }
 238
 239         function getWikiID() {
 240                 if( $this->mTablePrefix ) {
 241                         return "{$this->mDBname}-{$this->mTablePrefix}";
 242                 } else {
 243                         return $this->mDBname;
 244                 }
 245         }
 246
 247 #------------------------------------------------------------------------------
 248 # Other functions
 249 #------------------------------------------------------------------------------
 250
 251         /**@{{
 252          * Constructor.
 253          * @param string $server database server host
 254          * @param string $user database user name
 255          * @param string $password database user password
 256          * @param string $dbname database name
 257          * @param failFunction
 258          * @param $flags
 259          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 260          */
 261         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 262                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 263
 264                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 265                 # Can't get a reference if it hasn't been set yet
 266                 if ( !isset( $wgOut ) ) {
 267                         $wgOut = NULL;
 268                 }
 269
 270                 $this->mFailFunction = $failFunction;
 271                 $this->mFlags = $flags;
 272
 273                 if ( $this->mFlags & DBO_DEFAULT ) {
 274                         if ( $wgCommandLineMode ) {
 275                                 $this->mFlags &= ~DBO_TRX;
 276                         } else {
 277                                 $this->mFlags |= DBO_TRX;
 278                         }
 279                 }
 280
 281                 /*
 282                 // Faster read-only access
 283                 if ( wfReadOnly() ) {
 284                         $this->mFlags |= DBO_PERSISTENT;
 285                         $this->mFlags &= ~DBO_TRX;
 286                 }*/
 287
 288                 /** Get the default table prefix*/
 289                 if ( $tablePrefix == 'get from global' ) {
 290                         $this->mTablePrefix = $wgDBprefix;
 291                 } else {
 292                         $this->mTablePrefix = $tablePrefix;
 293                 }
 294
 295                 if ( $server ) {
 296                         $this->open( $server, $user, $password, $dbName );
 297                 }
 298         }
 299
 300         /**
 301          * @static
 302          * @param failFunction
 303          * @param $flags
 304          */
 305         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 306         {
 307                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 308         }
 309
 310         /**
 311          * Usually aborts on failure
 312          * If the failFunction is set to a non-zero integer, returns success
 313          */
 314         function open( $server, $user, $password, $dbName ) {
 315                 global $wgAllDBsAreLocalhost;
 316                 wfProfileIn( __METHOD__ );
 317
 318                 # Test for missing mysql.so
 319                 # First try to load it
 320                 if (!@extension_loaded('mysql')) {
 321                         @dl('mysql.so');
 322                 }
 323
 324                 # Fail now
 325                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 326                 if ( !function_exists( 'mysql_connect' ) ) {
 327                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 328                 }
 329
 330                 # Debugging hack -- fake cluster
 331                 if ( $wgAllDBsAreLocalhost ) {
 332                         $realServer = 'localhost';
 333                 } else {
 334                         $realServer = $server;
 335                 }
 336                 $this->close();
 337                 $this->mServer = $server;
 338                 $this->mUser = $user;
 339                 $this->mPassword = $password;
 340                 $this->mDBname = $dbName;
 341
 342                 $success = false;
 343
 344                 wfProfileIn("dbconnect-$server");
 345
 346                 # The kernel's default SYN retransmission period is far too slow for us,
 347                 # so we use a short timeout plus a manual retry. Retrying means that a small
 348                 # but finite rate of SYN packet loss won't cause user-visible errors.
 349                 $this->mConn = false;
 350                 if ( ini_get( 'mysql.connect_timeout' ) <= 3 ) {
 351                         $numAttempts = 2;
 352                 } else {
 353                         $numAttempts = 1;
 354                 }
 355                 $this->installErrorHandler();
 356                 for ( $i = 0; $i < $numAttempts && !$this->mConn; $i++ ) {
 357                         if ( $i > 1 ) {
 358                                 usleep( 1000 );
 359                         }
 360                         if ( $this->mFlags & DBO_PERSISTENT ) {
 361                                 $this->mConn = mysql_pconnect( $realServer, $user, $password );
 362                         } else {
 363                                 # Create a new connection...
 364                                 $this->mConn = mysql_connect( $realServer, $user, $password, true );
 365                         }
 366                         if ($this->mConn === false) {
 367                                 #$iplus = $i + 1;
 368                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 369                         }
 370                 }
 371                 $phpError = $this->restoreErrorHandler();
 372                 # Always log connection errors
 373                 if ( !$this->mConn ) {
 374                         $error = $this->lastError();
 375                         if ( !$error ) {
 376                                 $error = $phpError;
 377                         }
 378                         wfLogDBError( "Error connecting to {$this->mServer}: $error\n" );
 379                         wfDebug( "DB connection error\n" );
 380                         wfDebug( "Server: $server, User: $user, Password: " .
 381                                 substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 382                         $success = false;
 383                 }
 384
 385                 wfProfileOut("dbconnect-$server");
 386
 387                 if ( $dbName != '' && $this->mConn !== false ) {
 388                         $success = @/**/mysql_select_db( $dbName, $this->mConn );
 389                         if ( !$success ) {
 390                                 $error = "Error selecting database $dbName on server {$this->mServer} " .
 391                                         "from client host " . wfHostname() . "\n";
 392                                 wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 393                                 wfDebug( $error );
 394                         }
 395                 } else {
 396                         # Delay USE query
 397                         $success = (bool)$this->mConn;
 398                 }
 399
 400                 if ( $success ) {
 401                         $version = $this->getServerVersion();
 402                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 403                                 // Tell the server we're communicating with it in UTF-8.
 404                                 // This may engage various charset conversions.
 405                                 global $wgDBmysql5;
 406                                 if( $wgDBmysql5 ) {
 407                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 408                                 }
 409                                 // Turn off strict mode
 410                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 411                         }
 412
 413                         // Turn off strict mode if it is on
 414                 } else {
 415                         $this->reportConnectionError( $phpError );
 416                 }
 417
 418                 $this->mOpened = $success;
 419                 wfProfileOut( __METHOD__ );
 420                 return $success;
 421         }
 422         /**@}}*/
 423
 424         protected function installErrorHandler() {
 425                 $this->mPHPError = false;
 426                 $this->htmlErrors = ini_set( 'html_errors', '0' );
 427                 set_error_handler( array( $this, 'connectionErrorHandler' ) );
 428         }
 429
 430         protected function restoreErrorHandler() {
 431                 restore_error_handler();
 432                 if ( $this->htmlErrors !== false ) {
 433                         ini_set( 'html_errors', $this->htmlErrors );
 434                 }
 435                 if ( $this->mPHPError ) {
 436                         $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
 437                         $error = preg_replace( '!^.*?:(.*)$!', '$1', $error );
 438                         return $error;
 439                 } else {
 440                         return false;
 441                 }
 442         }
 443
 444         protected function connectionErrorHandler( $errno,  $errstr ) {
 445                 $this->mPHPError = $errstr;
 446         }
 447
 448         /**
 449          * Closes a database connection.
 450          * if it is open : commits any open transactions
 451          *
 452          * @return bool operation success. true if already closed.
 453          */
 454         function close()
 455         {
 456                 $this->mOpened = false;
 457                 if ( $this->mConn ) {
 458                         if ( $this->trxLevel() ) {
 459                                 $this->immediateCommit();
 460                         }
 461                         return mysql_close( $this->mConn );
 462                 } else {
 463                         return true;
 464                 }
 465         }
 466
 467         /**
 468          * @param string $error fallback error message, used if none is given by MySQL
 469          */
 470         function reportConnectionError( $error = 'Unknown error' ) {
 471                 $myError = $this->lastError();
 472                 if ( $myError ) {
 473                         $error = $myError;
 474                 }
 475
 476                 if ( $this->mFailFunction ) {
 477                         # Legacy error handling method
 478                         if ( !is_int( $this->mFailFunction ) ) {
 479                                 $ff = $this->mFailFunction;
 480                                 $ff( $this, $error );
 481                         }
 482                 } else {
 483                         # New method
 484                         throw new DBConnectionError( $this, $error );
 485                 }
 486         }
 487
 488         /**
 489          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 490          *
 491          * @param  $sql        String: SQL query
 492          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 493          *     comment (you can use __METHOD__ or add some extra info)
 494          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 495          *     maybe best to catch the exception instead?
 496          * @return true for a successful write query, ResultWrapper object for a successful read query,
 497          *     or false on failure if $tempIgnore set
 498          * @throws DBQueryError Thrown when the database returns an error of any kind
 499          */
 500         public function query( $sql, $fname = '', $tempIgnore = false ) {
 501                 global $wgProfiler;
 502
 503                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 504                 if ( isset( $wgProfiler ) ) {
 505                         # generalizeSQL will probably cut down the query to reasonable
 506                         # logging size most of the time. The substr is really just a sanity check.
 507
 508                         # Who's been wasting my precious column space? -- TS
 509                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 510
 511                         if ( $isMaster ) {
 512                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 513                                 $totalProf = 'Database::query-master';
 514                         } else {
 515                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 516                                 $totalProf = 'Database::query';
 517                         }
 518                         wfProfileIn( $totalProf );
 519                         wfProfileIn( $queryProf );
 520                 }
 521
 522                 $this->mLastQuery = $sql;
 523
 524                 # Add a comment for easy SHOW PROCESSLIST interpretation
 525                 #if ( $fname ) {
 526                         global $wgUser;
 527                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 528                                 $userName = $wgUser->getName();
 529                                 if ( mb_strlen( $userName ) > 15 ) {
 530                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 531                                 }
 532                                 $userName = str_replace( '/', '', $userName );
 533                         } else {
 534                                 $userName = '';
 535                         }
 536                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 537                 #} else {
 538                 #       $commentedSql = $sql;
 539                 #}
 540
 541                 # If DBO_TRX is set, start a transaction
 542                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 543                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 544                         // avoid establishing transactions for SHOW and SET statements too -
 545                         // that would delay transaction initializations to once connection
 546                         // is really used by application
 547                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 548                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 549                                 $this->begin();
 550                 }
 551
 552                 if ( $this->debug() ) {
 553                         $sqlx = substr( $commentedSql, 0, 500 );
 554                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 555                         if ( $isMaster ) {
 556                                 wfDebug( "SQL-master: $sqlx\n" );
 557                         } else {
 558                                 wfDebug( "SQL: $sqlx\n" );
 559                         }
 560                 }
 561
 562                 # Do the query and handle errors
 563                 $ret = $this->doQuery( $commentedSql );
 564
 565                 # Try reconnecting if the connection was lost
 566                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 567                         # Transaction is gone, like it or not
 568                         $this->mTrxLevel = 0;
 569                         wfDebug( "Connection lost, reconnecting...\n" );
 570                         if ( $this->ping() ) {
 571                                 wfDebug( "Reconnected\n" );
 572                                 $sqlx = substr( $commentedSql, 0, 500 );
 573                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 574                                 global $wgRequestTime;
 575                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 576                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 577                                 $ret = $this->doQuery( $commentedSql );
 578                         } else {
 579                                 wfDebug( "Failed\n" );
 580                         }
 581                 }
 582
 583                 if ( false === $ret ) {
 584                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 585                 }
 586
 587                 if ( isset( $wgProfiler ) ) {
 588                         wfProfileOut( $queryProf );
 589                         wfProfileOut( $totalProf );
 590                 }
 591                 return $this->resultObject( $ret );
 592         }
 593
 594         /**
 595          * The DBMS-dependent part of query()
 596          * @param  $sql String: SQL query.
 597          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 598          * @access private
 599          */
 600         /*private*/ function doQuery( $sql ) {
 601                 if( $this->bufferResults() ) {
 602                         $ret = mysql_query( $sql, $this->mConn );
 603                 } else {
 604                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 605                 }
 606                 return $ret;
 607         }
 608
 609         /**
 610          * @param $error
 611          * @param $errno
 612          * @param $sql
 613          * @param string $fname
 614          * @param bool $tempIgnore
 615          */
 616         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 617                 global $wgCommandLineMode;
 618                 # Ignore errors during error handling to avoid infinite recursion
 619                 $ignore = $this->ignoreErrors( true );
 620                 ++$this->mErrorCount;
 621
 622                 if( $ignore || $tempIgnore ) {
 623                         wfDebug("SQL ERROR (ignored): $error\n");
 624                         $this->ignoreErrors( $ignore );
 625                 } else {
 626                         $sql1line = str_replace( "\n", "\\n", $sql );
 627                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 628                         wfDebug("SQL ERROR: " . $error . "\n");
 629                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 630                 }
 631         }
 632
 633
 634         /**
 635          * Intended to be compatible with the PEAR::DB wrapper functions.
 636          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 637          *
 638          * ? = scalar value, quoted as necessary
 639          * ! = raw SQL bit (a function for instance)
 640          * & = filename; reads the file and inserts as a blob
 641          *     (we don't use this though...)
 642          */
 643         function prepare( $sql, $func = 'Database::prepare' ) {
 644                 /* MySQL doesn't support prepared statements (yet), so just
 645                    pack up the query for reference. We'll manually replace
 646                    the bits later. */
 647                 return array( 'query' => $sql, 'func' => $func );
 648         }
 649
 650         function freePrepared( $prepared ) {
 651                 /* No-op for MySQL */
 652         }
 653
 654         /**
 655          * Execute a prepared query with the various arguments
 656          * @param string $prepared the prepared sql
 657          * @param mixed $args Either an array here, or put scalars as varargs
 658          */
 659         function execute( $prepared, $args = null ) {
 660                 if( !is_array( $args ) ) {
 661                         # Pull the var args
 662                         $args = func_get_args();
 663                         array_shift( $args );
 664                 }
 665                 $sql = $this->fillPrepared( $prepared['query'], $args );
 666                 return $this->query( $sql, $prepared['func'] );
 667         }
 668
 669         /**
 670          * Prepare & execute an SQL statement, quoting and inserting arguments
 671          * in the appropriate places.
 672          * @param string $query
 673          * @param string $args ...
 674          */
 675         function safeQuery( $query, $args = null ) {
 676                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 677                 if( !is_array( $args ) ) {
 678                         # Pull the var args
 679                         $args = func_get_args();
 680                         array_shift( $args );
 681                 }
 682                 $retval = $this->execute( $prepared, $args );
 683                 $this->freePrepared( $prepared );
 684                 return $retval;
 685         }
 686
 687         /**
 688          * For faking prepared SQL statements on DBs that don't support
 689          * it directly.
 690          * @param string $preparedSql - a 'preparable' SQL statement
 691          * @param array $args - array of arguments to fill it with
 692          * @return string executable SQL
 693          */
 694         function fillPrepared( $preparedQuery, $args ) {
 695                 reset( $args );
 696                 $this->preparedArgs =& $args;
 697                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 698                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 699         }
 700
 701         /**
 702          * preg_callback func for fillPrepared()
 703          * The arguments should be in $this->preparedArgs and must not be touched
 704          * while we're doing this.
 705          *
 706          * @param array $matches
 707          * @return string
 708          * @private
 709          */
 710         function fillPreparedArg( $matches ) {
 711                 switch( $matches[1] ) {
 712                         case '\\?': return '?';
 713                         case '\\!': return '!';
 714                         case '\\&': return '&';
 715                 }
 716                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 717                 switch( $matches[1] ) {
 718                         case '?': return $this->addQuotes( $arg );
 719                         case '!': return $arg;
 720                         case '&':
 721                                 # return $this->addQuotes( file_get_contents( $arg ) );
 722                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 723                         default:
 724                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 725                 }
 726         }
 727
 728         /**#@+
 729          * @param mixed $res A SQL result
 730          */
 731         /**
 732          * Free a result object
 733          */
 734         function freeResult( $res ) {
 735                 if ( $res instanceof ResultWrapper ) {
 736                         $res = $res->result;
 737                 }
 738                 if ( !@/**/mysql_free_result( $res ) ) {
 739                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 740                 }
 741         }
 742
 743         /**
 744          * Fetch the next row from the given result object, in object form.
 745          * Fields can be retrieved with $row->fieldname, with fields acting like
 746          * member variables.
 747          *
 748          * @param $res SQL result object as returned from Database::query(), etc.
 749          * @return MySQL row object
 750          * @throws DBUnexpectedError Thrown if the database returns an error
 751          */
 752         function fetchObject( $res ) {
 753                 if ( $res instanceof ResultWrapper ) {
 754                         $res = $res->result;
 755                 }
 756                 @/**/$row = mysql_fetch_object( $res );
 757                 if( $this->lastErrno() ) {
 758                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 759                 }
 760                 return $row;
 761         }
 762
 763         /**
 764          * Fetch the next row from the given result object, in associative array
 765          * form.  Fields are retrieved with $row['fieldname'].
 766          *
 767          * @param $res SQL result object as returned from Database::query(), etc.
 768          * @return MySQL row object
 769          * @throws DBUnexpectedError Thrown if the database returns an error
 770          */
 771         function fetchRow( $res ) {
 772                 if ( $res instanceof ResultWrapper ) {
 773                         $res = $res->result;
 774                 }
 775                 @/**/$row = mysql_fetch_array( $res );
 776                 if ( $this->lastErrno() ) {
 777                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 778                 }
 779                 return $row;
 780         }
 781
 782         /**
 783          * Get the number of rows in a result object
 784          */
 785         function numRows( $res ) {
 786                 if ( $res instanceof ResultWrapper ) {
 787                         $res = $res->result;
 788                 }
 789                 @/**/$n = mysql_num_rows( $res );
 790                 if( $this->lastErrno() ) {
 791                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 792                 }
 793                 return $n;
 794         }
 795
 796         /**
 797          * Get the number of fields in a result object
 798          * See documentation for mysql_num_fields()
 799          */
 800         function numFields( $res ) {
 801                 if ( $res instanceof ResultWrapper ) {
 802                         $res = $res->result;
 803                 }
 804                 return mysql_num_fields( $res );
 805         }
 806
 807         /**
 808          * Get a field name in a result object
 809          * See documentation for mysql_field_name():
 810          * http://www.php.net/mysql_field_name
 811          */
 812         function fieldName( $res, $n ) {
 813                 if ( $res instanceof ResultWrapper ) {
 814                         $res = $res->result;
 815                 }
 816                 return mysql_field_name( $res, $n );
 817         }
 818
 819         /**
 820          * Get the inserted value of an auto-increment row
 821          *
 822          * The value inserted should be fetched from nextSequenceValue()
 823          *
 824          * Example:
 825          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 826          * $dbw->insert('page',array('page_id' => $id));
 827          * $id = $dbw->insertId();
 828          */
 829         function insertId() { return mysql_insert_id( $this->mConn ); }
 830
 831         /**
 832          * Change the position of the cursor in a result object
 833          * See mysql_data_seek()
 834          */
 835         function dataSeek( $res, $row ) {
 836                 if ( $res instanceof ResultWrapper ) {
 837                         $res = $res->result;
 838                 }
 839                 return mysql_data_seek( $res, $row );
 840         }
 841
 842         /**
 843          * Get the last error number
 844          * See mysql_errno()
 845          */
 846         function lastErrno() {
 847                 if ( $this->mConn ) {
 848                         return mysql_errno( $this->mConn );
 849                 } else {
 850                         return mysql_errno();
 851                 }
 852         }
 853
 854         /**
 855          * Get a description of the last error
 856          * See mysql_error() for more details
 857          */
 858         function lastError() {
 859                 if ( $this->mConn ) {
 860                         # Even if it's non-zero, it can still be invalid
 861                         wfSuppressWarnings();
 862                         $error = mysql_error( $this->mConn );
 863                         if ( !$error ) {
 864                                 $error = mysql_error();
 865                         }
 866                         wfRestoreWarnings();
 867                 } else {
 868                         $error = mysql_error();
 869                 }
 870                 if( $error ) {
 871                         $error .= ' (' . $this->mServer . ')';
 872                 }
 873                 return $error;
 874         }
 875         /**
 876          * Get the number of rows affected by the last write query
 877          * See mysql_affected_rows() for more details
 878          */
 879         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 880         /**#@-*/ // end of template : @param $result
 881
 882         /**
 883          * Simple UPDATE wrapper
 884          * Usually aborts on failure
 885          * If errors are explicitly ignored, returns success
 886          *
 887          * This function exists for historical reasons, Database::update() has a more standard
 888          * calling convention and feature set
 889          */
 890         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 891         {
 892                 $table = $this->tableName( $table );
 893                 $sql = "UPDATE $table SET $var = '" .
 894                   $this->strencode( $value ) . "' WHERE ($cond)";
 895                 return (bool)$this->query( $sql, $fname );
 896         }
 897
 898         /**
 899          * Simple SELECT wrapper, returns a single field, input must be encoded
 900          * Usually aborts on failure
 901          * If errors are explicitly ignored, returns FALSE on failure
 902          */
 903         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 904                 if ( !is_array( $options ) ) {
 905                         $options = array( $options );
 906                 }
 907                 $options['LIMIT'] = 1;
 908
 909                 $res = $this->select( $table, $var, $cond, $fname, $options );
 910                 if ( $res === false || !$this->numRows( $res ) ) {
 911                         return false;
 912                 }
 913                 $row = $this->fetchRow( $res );
 914                 if ( $row !== false ) {
 915                         $this->freeResult( $res );
 916                         return $row[0];
 917                 } else {
 918                         return false;
 919                 }
 920         }
 921
 922         /**
 923          * Returns an optional USE INDEX clause to go after the table, and a
 924          * string to go at the end of the query
 925          *
 926          * @private
 927          *
 928          * @param array $options an associative array of options to be turned into
 929          *              an SQL query, valid keys are listed in the function.
 930          * @return array
 931          */
 932         function makeSelectOptions( $options ) {
 933                 $preLimitTail = $postLimitTail = '';
 934                 $startOpts = '';
 935
 936                 $noKeyOptions = array();
 937                 foreach ( $options as $key => $option ) {
 938                         if ( is_numeric( $key ) ) {
 939                                 $noKeyOptions[$option] = true;
 940                         }
 941                 }
 942
 943                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 944                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 945                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 946
 947                 //if (isset($options['LIMIT'])) {
 948                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 949                 //              isset($options['OFFSET']) ? $options['OFFSET']
 950                 //              : false);
 951                 //}
 952
 953                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 954                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 955                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 956
 957                 # Various MySQL extensions
 958                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 959                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 960                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 961                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 962                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 963                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 964                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 965                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 966
 967                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 968                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 969                 } else {
 970                         $useIndex = '';
 971                 }
 972
 973                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 974         }
 975
 976         /**
 977          * SELECT wrapper
 978          *
 979          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 980          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 981          * @param mixed  $conds   Array or string, condition(s) for WHERE
 982          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 983          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 984          *                        see Database::makeSelectOptions code for list of supported stuff
 985          * @param array $join_conds Associative array of table join conditions (optional)
 986          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 987          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
 988          */
 989         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() )
 990         {
 991                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 992                 return $this->query( $sql, $fname );
 993         }
 994
 995         /**
 996          * SELECT wrapper
 997          *
 998          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 999          * @param mixed  $vars    Array or string, field name(s) to be retrieved
1000          * @param mixed  $conds   Array or string, condition(s) for WHERE
1001          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
1002          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1003          *                        see Database::makeSelectOptions code for list of supported stuff
1004          * @param array $join_conds Associative array of table join conditions (optional)
1005          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
1006          * @return string, the SQL text
1007          */
1008         function selectSQLText( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() ) {
1009                 if( is_array( $vars ) ) {
1010                         $vars = implode( ',', $vars );
1011                 }
1012                 if( !is_array( $options ) ) {
1013                         $options = array( $options );
1014                 }
1015                 if( is_array( $table ) ) {
1016                         if ( !empty($join_conds) || ( isset( $options['USE INDEX'] ) && is_array( @$options['USE INDEX'] ) ) )
1017                                 $from = ' FROM ' . $this->tableNamesWithUseIndexOrJOIN( $table, @$options['USE INDEX'], $join_conds );
1018                         else
1019                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1020                 } elseif ($table!='') {
1021                         if ($table{0}==' ') {
1022                                 $from = ' FROM ' . $table;
1023                         } else {
1024                                 $from = ' FROM ' . $this->tableName( $table );
1025                         }
1026                 } else {
1027                         $from = '';
1028                 }
1029
1030                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
1031
1032                 if( !empty( $conds ) ) {
1033                         if ( is_array( $conds ) ) {
1034                                 $conds = $this->makeList( $conds, LIST_AND );
1035                         }
1036                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
1037                 } else {
1038                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
1039                 }
1040
1041                 if (isset($options['LIMIT']))
1042                         $sql = $this->limitResult($sql, $options['LIMIT'],
1043                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
1044                 $sql = "$sql $postLimitTail";
1045
1046                 if (isset($options['EXPLAIN'])) {
1047                         $sql = 'EXPLAIN ' . $sql;
1048                 }
1049                 return $sql;
1050         }
1051
1052         /**
1053          * Single row SELECT wrapper
1054          * Aborts or returns FALSE on error
1055          *
1056          * $vars: the selected variables
1057          * $conds: a condition map, terms are ANDed together.
1058          *   Items with numeric keys are taken to be literal conditions
1059          * Takes an array of selected variables, and a condition map, which is ANDed
1060          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1061          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1062          * $obj- >page_id is the ID of the Astronomy article
1063          *
1064          * @todo migrate documentation to phpdocumentor format
1065          */
1066         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array(), $join_conds = array() ) {
1067                 $options['LIMIT'] = 1;
1068                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1069                 if ( $res === false )
1070                         return false;
1071                 if ( !$this->numRows($res) ) {
1072                         $this->freeResult($res);
1073                         return false;
1074                 }
1075                 $obj = $this->fetchObject( $res );
1076                 $this->freeResult( $res );
1077                 return $obj;
1078
1079         }
1080
1081         /**
1082          * Estimate rows in dataset
1083          * Returns estimated count, based on EXPLAIN output
1084          * Takes same arguments as Database::select()
1085          */
1086
1087         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1088                 $options['EXPLAIN']=true;
1089                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1090                 if ( $res === false )
1091                         return false;
1092                 if (!$this->numRows($res)) {
1093                         $this->freeResult($res);
1094                         return 0;
1095                 }
1096
1097                 $rows=1;
1098
1099                 while( $plan = $this->fetchObject( $res ) ) {
1100                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1101                 }
1102
1103                 $this->freeResult($res);
1104                 return $rows;
1105         }
1106
1107
1108         /**
1109          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1110          * It's only slightly flawed. Don't use for anything important.
1111          *
1112          * @param string $sql A SQL Query
1113          * @static
1114          */
1115         static function generalizeSQL( $sql ) {
1116                 # This does the same as the regexp below would do, but in such a way
1117                 # as to avoid crashing php on some large strings.
1118                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1119
1120                 $sql = str_replace ( "\\\\", '', $sql);
1121                 $sql = str_replace ( "\\'", '', $sql);
1122                 $sql = str_replace ( "\\\"", '', $sql);
1123                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1124                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1125
1126                 # All newlines, tabs, etc replaced by single space
1127                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1128
1129                 # All numbers => N
1130                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1131
1132                 return $sql;
1133         }
1134
1135         /**
1136          * Determines whether a field exists in a table
1137          * Usually aborts on failure
1138          * If errors are explicitly ignored, returns NULL on failure
1139          */
1140         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1141                 $table = $this->tableName( $table );
1142                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1143                 if ( !$res ) {
1144                         return NULL;
1145                 }
1146
1147                 $found = false;
1148
1149                 while ( $row = $this->fetchObject( $res ) ) {
1150                         if ( $row->Field == $field ) {
1151                                 $found = true;
1152                                 break;
1153                         }
1154                 }
1155                 return $found;
1156         }
1157
1158         /**
1159          * Determines whether an index exists
1160          * Usually aborts on failure
1161          * If errors are explicitly ignored, returns NULL on failure
1162          */
1163         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1164                 $info = $this->indexInfo( $table, $index, $fname );
1165                 if ( is_null( $info ) ) {
1166                         return NULL;
1167                 } else {
1168                         return $info !== false;
1169                 }
1170         }
1171
1172
1173         /**
1174          * Get information about an index into an object
1175          * Returns false if the index does not exist
1176          */
1177         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1178                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1179                 # SHOW INDEX should work for 3.x and up:
1180                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1181                 $table = $this->tableName( $table );
1182                 $sql = 'SHOW INDEX FROM '.$table;
1183                 $res = $this->query( $sql, $fname );
1184                 if ( !$res ) {
1185                         return NULL;
1186                 }
1187
1188                 $result = array();
1189                 while ( $row = $this->fetchObject( $res ) ) {
1190                         if ( $row->Key_name == $index ) {
1191                                 $result[] = $row;
1192                         }
1193                 }
1194                 $this->freeResult($res);
1195
1196                 return empty($result) ? false : $result;
1197         }
1198
1199         /**
1200          * Query whether a given table exists
1201          */
1202         function tableExists( $table ) {
1203                 $table = $this->tableName( $table );
1204                 $old = $this->ignoreErrors( true );
1205                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1206                 $this->ignoreErrors( $old );
1207                 if( $res ) {
1208                         $this->freeResult( $res );
1209                         return true;
1210                 } else {
1211                         return false;
1212                 }
1213         }
1214
1215         /**
1216          * mysql_fetch_field() wrapper
1217          * Returns false if the field doesn't exist
1218          *
1219          * @param $table
1220          * @param $field
1221          */
1222         function fieldInfo( $table, $field ) {
1223                 $table = $this->tableName( $table );
1224                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1225                 $n = mysql_num_fields( $res->result );
1226                 for( $i = 0; $i < $n; $i++ ) {
1227                         $meta = mysql_fetch_field( $res->result, $i );
1228                         if( $field == $meta->name ) {
1229                                 return new MySQLField($meta);
1230                         }
1231                 }
1232                 return false;
1233         }
1234
1235         /**
1236          * mysql_field_type() wrapper
1237          */
1238         function fieldType( $res, $index ) {
1239                 if ( $res instanceof ResultWrapper ) {
1240                         $res = $res->result;
1241                 }
1242                 return mysql_field_type( $res, $index );
1243         }
1244
1245         /**
1246          * Determines if a given index is unique
1247          */
1248         function indexUnique( $table, $index ) {
1249                 $indexInfo = $this->indexInfo( $table, $index );
1250                 if ( !$indexInfo ) {
1251                         return NULL;
1252                 }
1253                 return !$indexInfo[0]->Non_unique;
1254         }
1255
1256         /**
1257          * INSERT wrapper, inserts an array into a table
1258          *
1259          * $a may be a single associative array, or an array of these with numeric keys, for
1260          * multi-row insert.
1261          *
1262          * Usually aborts on failure
1263          * If errors are explicitly ignored, returns success
1264          */
1265         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1266                 # No rows to insert, easy just return now
1267                 if ( !count( $a ) ) {
1268                         return true;
1269                 }
1270
1271                 $table = $this->tableName( $table );
1272                 if ( !is_array( $options ) ) {
1273                         $options = array( $options );
1274                 }
1275                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1276                         $multi = true;
1277                         $keys = array_keys( $a[0] );
1278                 } else {
1279                         $multi = false;
1280                         $keys = array_keys( $a );
1281                 }
1282
1283                 $sql = 'INSERT ' . implode( ' ', $options ) .
1284                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1285
1286                 if ( $multi ) {
1287                         $first = true;
1288                         foreach ( $a as $row ) {
1289                                 if ( $first ) {
1290                                         $first = false;
1291                                 } else {
1292                                         $sql .= ',';
1293                                 }
1294                                 $sql .= '(' . $this->makeList( $row ) . ')';
1295                         }
1296                 } else {
1297                         $sql .= '(' . $this->makeList( $a ) . ')';
1298                 }
1299                 return (bool)$this->query( $sql, $fname );
1300         }
1301
1302         /**
1303          * Make UPDATE options for the Database::update function
1304          *
1305          * @private
1306          * @param array $options The options passed to Database::update
1307          * @return string
1308          */
1309         function makeUpdateOptions( $options ) {
1310                 if( !is_array( $options ) ) {
1311                         $options = array( $options );
1312                 }
1313                 $opts = array();
1314                 if ( in_array( 'LOW_PRIORITY', $options ) )
1315                         $opts[] = $this->lowPriorityOption();
1316                 if ( in_array( 'IGNORE', $options ) )
1317                         $opts[] = 'IGNORE';
1318                 return implode(' ', $opts);
1319         }
1320
1321         /**
1322          * UPDATE wrapper, takes a condition array and a SET array
1323          *
1324          * @param string $table  The table to UPDATE
1325          * @param array  $values An array of values to SET
1326          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1327          * @param string $fname  The Class::Function calling this function
1328          *                       (for the log)
1329          * @param array  $options An array of UPDATE options, can be one or
1330          *                        more of IGNORE, LOW_PRIORITY
1331          * @return bool
1332          */
1333         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1334                 $table = $this->tableName( $table );
1335                 $opts = $this->makeUpdateOptions( $options );
1336                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1337                 if ( $conds != '*' ) {
1338                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1339                 }
1340                 return $this->query( $sql, $fname );
1341         }
1342
1343         /**
1344          * Makes an encoded list of strings from an array
1345          * $mode:
1346          *        LIST_COMMA         - comma separated, no field names
1347          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1348          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1349          *        LIST_SET           - comma separated with field names, like a SET clause
1350          *        LIST_NAMES         - comma separated field names
1351          */
1352         function makeList( $a, $mode = LIST_COMMA ) {
1353                 if ( !is_array( $a ) ) {
1354                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1355                 }
1356
1357                 $first = true;
1358                 $list = '';
1359                 foreach ( $a as $field => $value ) {
1360                         if ( !$first ) {
1361                                 if ( $mode == LIST_AND ) {
1362                                         $list .= ' AND ';
1363                                 } elseif($mode == LIST_OR) {
1364                                         $list .= ' OR ';
1365                                 } else {
1366                                         $list .= ',';
1367                                 }
1368                         } else {
1369                                 $first = false;
1370                         }
1371                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1372                                 $list .= "($value)";
1373                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1374                                 $list .= "$value";
1375                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1376                                 if( count( $value ) == 0 ) {
1377                                         throw new MWException( __METHOD__.': empty input' );
1378                                 } elseif( count( $value ) == 1 ) {
1379                                         // Special-case single values, as IN isn't terribly efficient
1380                                         // Don't necessarily assume the single key is 0; we don't
1381                                         // enforce linear numeric ordering on other arrays here.
1382                                         $value = array_values( $value );
1383                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1384                                 } else {
1385                                         $list .= $field." IN (".$this->makeList($value).") ";
1386                                 }
1387                         } elseif( is_null($value) ) {
1388                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1389                                         $list .= "$field IS ";
1390                                 } elseif ( $mode == LIST_SET ) {
1391                                         $list .= "$field = ";
1392                                 }
1393                                 $list .= 'NULL';
1394                         } else {
1395                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1396                                         $list .= "$field = ";
1397                                 }
1398                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1399                         }
1400                 }
1401                 return $list;
1402         }
1403
1404         /**
1405          * Change the current database
1406          */
1407         function selectDB( $db ) {
1408                 $this->mDBname = $db;
1409                 return mysql_select_db( $db, $this->mConn );
1410         }
1411
1412         /**
1413          * Get the current DB name
1414          */
1415         function getDBname() {
1416                 return $this->mDBname;
1417         }
1418
1419         /**
1420          * Get the server hostname or IP address
1421          */
1422         function getServer() {
1423                 return $this->mServer;
1424         }
1425
1426         /**
1427          * Format a table name ready for use in constructing an SQL query
1428          *
1429          * This does two important things: it quotes the table names to clean them up,
1430          * and it adds a table prefix if only given a table name with no quotes.
1431          *
1432          * All functions of this object which require a table name call this function
1433          * themselves. Pass the canonical name to such functions. This is only needed
1434          * when calling query() directly.
1435          *
1436          * @param string $name database table name
1437          * @return string full database name
1438          */
1439         function tableName( $name ) {
1440                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1441                 # Skip the entire process when we have a string quoted on both ends.
1442                 # Note that we check the end so that we will still quote any use of
1443                 # use of `database`.table. But won't break things if someone wants
1444                 # to query a database table with a dot in the name.
1445                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) return $name;
1446
1447                 # Lets test for any bits of text that should never show up in a table
1448                 # name. Basically anything like JOIN or ON which are actually part of
1449                 # SQL queries, but may end up inside of the table value to combine
1450                 # sql. Such as how the API is doing.
1451                 # Note that we use a whitespace test rather than a \b test to avoid
1452                 # any remote case where a word like on may be inside of a table name
1453                 # surrounded by symbols which may be considered word breaks.
1454                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) return $name;
1455
1456                 # Split database and table into proper variables.
1457                 # We reverse the explode so that database.table and table both output
1458                 # the correct table.
1459                 $dbDetails = array_reverse( explode( '.', $name, 2 ) );
1460                 if( isset( $dbDetails[1] ) ) @list( $table, $database ) = $dbDetails;
1461                 else                         @list( $table ) = $dbDetails;
1462                 $prefix = $this->mTablePrefix; # Default prefix
1463
1464                 # A database name has been specified in input. Quote the table name
1465                 # because we don't want any prefixes added.
1466                 if( isset($database) ) $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1467
1468                 # Note that we use the long format because php will complain in in_array if
1469                 # the input is not an array, and will complain in is_array if it is not set.
1470                 if( !isset( $database ) # Don't use shared database if pre selected.
1471                  && isset( $wgSharedDB ) # We have a shared database
1472                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1473                  && isset( $wgSharedTables )
1474                  && is_array( $wgSharedTables )
1475                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1476                         $database = $wgSharedDB;
1477                         $prefix   = isset( $wgSharedPrefix ) ? $wgSharedPrefix : $prefix;
1478                 }
1479
1480                 # Quote the $database and $table and apply the prefix if not quoted.
1481                 if( isset($database) ) $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1482                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1483
1484                 # Merge our database and table into our final table name.
1485                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1486
1487                 # We're finished, return.
1488                 return $tableName;
1489         }
1490
1491         /**
1492          * Fetch a number of table names into an array
1493          * This is handy when you need to construct SQL for joins
1494          *
1495          * Example:
1496          * extract($dbr->tableNames('user','watchlist'));
1497          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1498          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1499          */
1500         public function tableNames() {
1501                 $inArray = func_get_args();
1502                 $retVal = array();
1503                 foreach ( $inArray as $name ) {
1504                         $retVal[$name] = $this->tableName( $name );
1505                 }
1506                 return $retVal;
1507         }
1508
1509         /**
1510          * Fetch a number of table names into an zero-indexed numerical array
1511          * This is handy when you need to construct SQL for joins
1512          *
1513          * Example:
1514          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1515          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1516          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1517          */
1518         public function tableNamesN() {
1519                 $inArray = func_get_args();
1520                 $retVal = array();
1521                 foreach ( $inArray as $name ) {
1522                         $retVal[] = $this->tableName( $name );
1523                 }
1524                 return $retVal;
1525         }
1526
1527         /**
1528          * @private
1529          */
1530         function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1531                 $ret = array();
1532                 $retJOIN = array();
1533                 $use_index_safe = is_array($use_index) ? $use_index : array();
1534                 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1535                 foreach ( $tables as $table ) {
1536                         // Is there a JOIN and INDEX clause for this table?
1537                         if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1538                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1539                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1540                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1541                                 $retJOIN[] = $tableClause;
1542                         // Is there an INDEX clause?
1543                         } else if ( isset($use_index_safe[$table]) ) {
1544                                 $tableClause = $this->tableName( $table );
1545                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1546                                 $ret[] = $tableClause;
1547                         // Is there a JOIN clause?
1548                         } else if ( isset($join_conds_safe[$table]) ) {
1549                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1550                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1551                                 $retJOIN[] = $tableClause;
1552                         } else {
1553                                 $tableClause = $this->tableName( $table );
1554                                 $ret[] = $tableClause;
1555                         }
1556                 }
1557                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1558                 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1559                 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1560                 // Compile our final table clause
1561                 return implode(' ',array($straightJoins,$otherJoins) );
1562         }
1563
1564         /**
1565          * Wrapper for addslashes()
1566          * @param string $s String to be slashed.
1567          * @return string slashed string.
1568          */
1569         function strencode( $s ) {
1570                 return mysql_real_escape_string( $s, $this->mConn );
1571         }
1572
1573         /**
1574          * If it's a string, adds quotes and backslashes
1575          * Otherwise returns as-is
1576          */
1577         function addQuotes( $s ) {
1578                 if ( is_null( $s ) ) {
1579                         return 'NULL';
1580                 } else {
1581                         # This will also quote numeric values. This should be harmless,
1582                         # and protects against weird problems that occur when they really
1583                         # _are_ strings such as article titles and string->number->string
1584                         # conversion is not 1:1.
1585                         return "'" . $this->strencode( $s ) . "'";
1586                 }
1587         }
1588
1589         /**
1590          * Escape string for safe LIKE usage
1591          */
1592         function escapeLike( $s ) {
1593                 $s=$this->strencode( $s );
1594                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1595                 return $s;
1596         }
1597
1598         /**
1599          * Returns an appropriately quoted sequence value for inserting a new row.
1600          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1601          * subclass will return an integer, and save the value for insertId()
1602          */
1603         function nextSequenceValue( $seqName ) {
1604                 return NULL;
1605         }
1606
1607         /**
1608          * USE INDEX clause
1609          * PostgreSQL doesn't have them and returns ""
1610          */
1611         function useIndexClause( $index ) {
1612                 return "FORCE INDEX ($index)";
1613         }
1614
1615         /**
1616          * REPLACE query wrapper
1617          * PostgreSQL simulates this with a DELETE followed by INSERT
1618          * $row is the row to insert, an associative array
1619          * $uniqueIndexes is an array of indexes. Each element may be either a
1620          * field name or an array of field names
1621          *
1622          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1623          * However if you do this, you run the risk of encountering errors which wouldn't have
1624          * occurred in MySQL
1625          *
1626          * @todo migrate comment to phodocumentor format
1627          */
1628         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1629                 $table = $this->tableName( $table );
1630
1631                 # Single row case
1632                 if ( !is_array( reset( $rows ) ) ) {
1633                         $rows = array( $rows );
1634                 }
1635
1636                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1637                 $first = true;
1638                 foreach ( $rows as $row ) {
1639                         if ( $first ) {
1640                                 $first = false;
1641                         } else {
1642                                 $sql .= ',';
1643                         }
1644                         $sql .= '(' . $this->makeList( $row ) . ')';
1645                 }
1646                 return $this->query( $sql, $fname );
1647         }
1648
1649         /**
1650          * DELETE where the condition is a join
1651          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1652          *
1653          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1654          * join condition matches, set $conds='*'
1655          *
1656          * DO NOT put the join condition in $conds
1657          *
1658          * @param string $delTable The table to delete from.
1659          * @param string $joinTable The other table.
1660          * @param string $delVar The variable to join on, in the first table.
1661          * @param string $joinVar The variable to join on, in the second table.
1662          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1663          */
1664         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1665                 if ( !$conds ) {
1666                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1667                 }
1668
1669                 $delTable = $this->tableName( $delTable );
1670                 $joinTable = $this->tableName( $joinTable );
1671                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1672                 if ( $conds != '*' ) {
1673                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1674                 }
1675
1676                 return $this->query( $sql, $fname );
1677         }
1678
1679         /**
1680          * Returns the size of a text field, or -1 for "unlimited"
1681          */
1682         function textFieldSize( $table, $field ) {
1683                 $table = $this->tableName( $table );
1684                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1685                 $res = $this->query( $sql, 'Database::textFieldSize' );
1686                 $row = $this->fetchObject( $res );
1687                 $this->freeResult( $res );
1688
1689                 $m = array();
1690                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1691                         $size = $m[1];
1692                 } else {
1693                         $size = -1;
1694                 }
1695                 return $size;
1696         }
1697
1698         /**
1699          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1700          */
1701         function lowPriorityOption() {
1702                 return 'LOW_PRIORITY';
1703         }
1704
1705         /**
1706          * DELETE query wrapper
1707          *
1708          * Use $conds == "*" to delete all rows
1709          */
1710         function delete( $table, $conds, $fname = 'Database::delete' ) {
1711                 if ( !$conds ) {
1712                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1713                 }
1714                 $table = $this->tableName( $table );
1715                 $sql = "DELETE FROM $table";
1716                 if ( $conds != '*' ) {
1717                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1718                 }
1719                 return $this->query( $sql, $fname );
1720         }
1721
1722         /**
1723          * INSERT SELECT wrapper
1724          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1725          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1726          * $conds may be "*" to copy the whole table
1727          * srcTable may be an array of tables.
1728          */
1729         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1730                 $insertOptions = array(), $selectOptions = array() )
1731         {
1732                 $destTable = $this->tableName( $destTable );
1733                 if ( is_array( $insertOptions ) ) {
1734                         $insertOptions = implode( ' ', $insertOptions );
1735                 }
1736                 if( !is_array( $selectOptions ) ) {
1737                         $selectOptions = array( $selectOptions );
1738                 }
1739                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1740                 if( is_array( $srcTable ) ) {
1741                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1742                 } else {
1743                         $srcTable = $this->tableName( $srcTable );
1744                 }
1745                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1746                         " SELECT $startOpts " . implode( ',', $varMap ) .
1747                         " FROM $srcTable $useIndex ";
1748                 if ( $conds != '*' ) {
1749                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1750                 }
1751                 $sql .= " $tailOpts";
1752                 return $this->query( $sql, $fname );
1753         }
1754
1755         /**
1756          * Construct a LIMIT query with optional offset
1757          * This is used for query pages
1758          * $sql string SQL query we will append the limit too
1759          * $limit integer the SQL limit
1760          * $offset integer the SQL offset (default false)
1761          */
1762         function limitResult($sql, $limit, $offset=false) {
1763                 if( !is_numeric($limit) ) {
1764                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1765                 }
1766                 return "$sql LIMIT "
1767                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1768                                 . "{$limit} ";
1769         }
1770         function limitResultForUpdate($sql, $num) {
1771                 return $this->limitResult($sql, $num, 0);
1772         }
1773
1774         /**
1775          * Returns an SQL expression for a simple conditional.
1776          * Uses IF on MySQL.
1777          *
1778          * @param string $cond SQL expression which will result in a boolean value
1779          * @param string $trueVal SQL expression to return if true
1780          * @param string $falseVal SQL expression to return if false
1781          * @return string SQL fragment
1782          */
1783         function conditional( $cond, $trueVal, $falseVal ) {
1784                 return " IF($cond, $trueVal, $falseVal) ";
1785         }
1786
1787         /**
1788          * Returns a comand for str_replace function in SQL query.
1789          * Uses REPLACE() in MySQL
1790          *
1791          * @param string $orig String or column to modify
1792          * @param string $old String or column to seek
1793          * @param string $new String or column to replace with
1794          */
1795         function strreplace( $orig, $old, $new ) {
1796                 return "REPLACE({$orig}, {$old}, {$new})";
1797         }
1798
1799         /**
1800          * Determines if the last failure was due to a deadlock
1801          */
1802         function wasDeadlock() {
1803                 return $this->lastErrno() == 1213;
1804         }
1805
1806         /**
1807          * Perform a deadlock-prone transaction.
1808          *
1809          * This function invokes a callback function to perform a set of write
1810          * queries. If a deadlock occurs during the processing, the transaction
1811          * will be rolled back and the callback function will be called again.
1812          *
1813          * Usage:
1814          *   $dbw->deadlockLoop( callback, ... );
1815          *
1816          * Extra arguments are passed through to the specified callback function.
1817          *
1818          * Returns whatever the callback function returned on its successful,
1819          * iteration, or false on error, for example if the retry limit was
1820          * reached.
1821          */
1822         function deadlockLoop() {
1823                 $myFname = 'Database::deadlockLoop';
1824
1825                 $this->begin();
1826                 $args = func_get_args();
1827                 $function = array_shift( $args );
1828                 $oldIgnore = $this->ignoreErrors( true );
1829                 $tries = DEADLOCK_TRIES;
1830                 if ( is_array( $function ) ) {
1831                         $fname = $function[0];
1832                 } else {
1833                         $fname = $function;
1834                 }
1835                 do {
1836                         $retVal = call_user_func_array( $function, $args );
1837                         $error = $this->lastError();
1838                         $errno = $this->lastErrno();
1839                         $sql = $this->lastQuery();
1840
1841                         if ( $errno ) {
1842                                 if ( $this->wasDeadlock() ) {
1843                                         # Retry
1844                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1845                                 } else {
1846                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1847                                 }
1848                         }
1849                 } while( $this->wasDeadlock() && --$tries > 0 );
1850                 $this->ignoreErrors( $oldIgnore );
1851                 if ( $tries <= 0 ) {
1852                         $this->query( 'ROLLBACK', $myFname );
1853                         $this->reportQueryError( $error, $errno, $sql, $fname );
1854                         return false;
1855                 } else {
1856                         $this->query( 'COMMIT', $myFname );
1857                         return $retVal;
1858                 }
1859         }
1860
1861         /**
1862          * Do a SELECT MASTER_POS_WAIT()
1863          *
1864          * @param string $file the binlog file
1865          * @param string $pos the binlog position
1866          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1867          */
1868         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1869                 $fname = 'Database::masterPosWait';
1870                 wfProfileIn( $fname );
1871
1872                 # Commit any open transactions
1873                 if ( $this->mTrxLevel ) {
1874                         $this->immediateCommit();
1875                 }
1876
1877                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1878                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1879                         if ( $wait > $timeout * 1e6 ) {
1880                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1881                                 wfProfileOut( $fname );
1882                                 return -1;
1883                         } elseif ( $wait > 0 ) {
1884                                 wfDebug( "Fake slave waiting $wait us\n" );
1885                                 usleep( $wait );
1886                                 wfProfileOut( $fname );
1887                                 return 1;
1888                         } else {
1889                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1890                                 wfProfileOut( $fname );
1891                                 return 0;
1892                         }
1893                 }
1894
1895                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1896                 $encFile = $this->addQuotes( $pos->file );
1897                 $encPos = intval( $pos->pos );
1898                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1899                 $res = $this->doQuery( $sql );
1900                 if ( $res && $row = $this->fetchRow( $res ) ) {
1901                         $this->freeResult( $res );
1902                         wfProfileOut( $fname );
1903                         return $row[0];
1904                 } else {
1905                         wfProfileOut( $fname );
1906                         return false;
1907                 }
1908         }
1909
1910         /**
1911          * Get the position of the master from SHOW SLAVE STATUS
1912          */
1913         function getSlavePos() {
1914                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1915                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1916                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1917                         return $pos;
1918                 }
1919                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1920                 $row = $this->fetchObject( $res );
1921                 if ( $row ) {
1922                         return new MySQLMasterPos( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1923                 } else {
1924                         return false;
1925                 }
1926         }
1927
1928         /**
1929          * Get the position of the master from SHOW MASTER STATUS
1930          */
1931         function getMasterPos() {
1932                 if ( $this->mFakeMaster ) {
1933                         return new MySQLMasterPos( 'fake', microtime( true ) );
1934                 }
1935                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1936                 $row = $this->fetchObject( $res );
1937                 if ( $row ) {
1938                         return new MySQLMasterPos( $row->File, $row->Position );
1939                 } else {
1940                         return false;
1941                 }
1942         }
1943
1944         /**
1945          * Begin a transaction, committing any previously open transaction
1946          */
1947         function begin( $fname = 'Database::begin' ) {
1948                 $this->query( 'BEGIN', $fname );
1949                 $this->mTrxLevel = 1;
1950         }
1951
1952         /**
1953          * End a transaction
1954          */
1955         function commit( $fname = 'Database::commit' ) {
1956                 $this->query( 'COMMIT', $fname );
1957                 $this->mTrxLevel = 0;
1958         }
1959
1960         /**
1961          * Rollback a transaction.
1962          * No-op on non-transactional databases.
1963          */
1964         function rollback( $fname = 'Database::rollback' ) {
1965                 $this->query( 'ROLLBACK', $fname, true );
1966                 $this->mTrxLevel = 0;
1967         }
1968
1969         /**
1970          * Begin a transaction, committing any previously open transaction
1971          * @deprecated use begin()
1972          */
1973         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1974                 $this->begin();
1975         }
1976
1977         /**
1978          * Commit transaction, if one is open
1979          * @deprecated use commit()
1980          */
1981         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1982                 $this->commit();
1983         }
1984
1985         /**
1986          * Return MW-style timestamp used for MySQL schema
1987          */
1988         function timestamp( $ts=0 ) {
1989                 return wfTimestamp(TS_MW,$ts);
1990         }
1991
1992         /**
1993          * Local database timestamp format or null
1994          */
1995         function timestampOrNull( $ts = null ) {
1996                 if( is_null( $ts ) ) {
1997                         return null;
1998                 } else {
1999                         return $this->timestamp( $ts );
2000                 }
2001         }
2002
2003         /**
2004          * @todo document
2005          */
2006         function resultObject( $result ) {
2007                 if( empty( $result ) ) {
2008                         return false;
2009                 } elseif ( $result instanceof ResultWrapper ) {
2010                         return $result;
2011                 } elseif ( $result === true ) {
2012                         // Successful write query
2013                         return $result;
2014                 } else {
2015                         return new ResultWrapper( $this, $result );
2016                 }
2017         }
2018
2019         /**
2020          * Return aggregated value alias
2021          */
2022         function aggregateValue ($valuedata,$valuename='value') {
2023                 return $valuename;
2024         }
2025
2026         /**
2027          * @return string wikitext of a link to the server software's web site
2028          */
2029         function getSoftwareLink() {
2030                 return "[http://www.mysql.com/ MySQL]";
2031         }
2032
2033         /**
2034          * @return string Version information from the database
2035          */
2036         function getServerVersion() {
2037                 return mysql_get_server_info( $this->mConn );
2038         }
2039
2040         /**
2041          * Ping the server and try to reconnect if it there is no connection
2042          */
2043         function ping() {
2044                 if( !function_exists( 'mysql_ping' ) ) {
2045                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
2046                         return true;
2047                 }
2048                 $ping = mysql_ping( $this->mConn );
2049                 if ( $ping ) {
2050                         return true;
2051                 }
2052
2053                 // Need to reconnect manually in MySQL client 5.0.13+
2054                 if ( version_compare( mysql_get_client_info(), '5.0.13', '>=' ) ) {
2055                         mysql_close( $this->mConn );
2056                         $this->mOpened = false;
2057                         $this->mConn = false;
2058                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
2059                         return true;
2060                 }
2061                 return false;
2062         }
2063
2064         /**
2065          * Get slave lag.
2066          * At the moment, this will only work if the DB user has the PROCESS privilege
2067          */
2068         function getLag() {
2069                 if ( !is_null( $this->mFakeSlaveLag ) ) {
2070                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
2071                         return $this->mFakeSlaveLag;
2072                 }
2073                 $res = $this->query( 'SHOW PROCESSLIST' );
2074                 # Find slave SQL thread
2075                 while ( $row = $this->fetchObject( $res ) ) {
2076                         /* This should work for most situations - when default db
2077                          * for thread is not specified, it had no events executed,
2078                          * and therefore it doesn't know yet how lagged it is.
2079                          *
2080                          * Relay log I/O thread does not select databases.
2081                          */
2082                         if ( $row->User == 'system user' &&
2083                                 $row->State != 'Waiting for master to send event' &&
2084                                 $row->State != 'Connecting to master' &&
2085                                 $row->State != 'Queueing master event to the relay log' &&
2086                                 $row->State != 'Waiting for master update' &&
2087                                 $row->State != 'Requesting binlog dump'
2088                                 ) {
2089                                 # This is it, return the time (except -ve)
2090                                 if ( $row->Time > 0x7fffffff ) {
2091                                         return false;
2092                                 } else {
2093                                         return $row->Time;
2094                                 }
2095                         }
2096                 }
2097                 return false;
2098         }
2099
2100         /**
2101          * Get status information from SHOW STATUS in an associative array
2102          */
2103         function getStatus($which="%") {
2104                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2105                 $status = array();
2106                 while ( $row = $this->fetchObject( $res ) ) {
2107                         $status[$row->Variable_name] = $row->Value;
2108                 }
2109                 return $status;
2110         }
2111
2112         /**
2113          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2114          */
2115         function maxListLen() {
2116                 return 0;
2117         }
2118
2119         function encodeBlob($b) {
2120                 return $b;
2121         }
2122
2123         function decodeBlob($b) {
2124                 return $b;
2125         }
2126
2127         /**
2128          * Override database's default connection timeout.
2129          * May be useful for very long batch queries such as
2130          * full-wiki dumps, where a single query reads out
2131          * over hours or days.
2132          * @param int $timeout in seconds
2133          */
2134         public function setTimeout( $timeout ) {
2135                 $this->query( "SET net_read_timeout=$timeout" );
2136                 $this->query( "SET net_write_timeout=$timeout" );
2137         }
2138
2139         /**
2140          * Read and execute SQL commands from a file.
2141          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2142          * @param string $filename File name to open
2143          * @param callback $lineCallback Optional function called before reading each line
2144          * @param callback $resultCallback Optional function called for each MySQL result
2145          */
2146         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2147                 $fp = fopen( $filename, 'r' );
2148                 if ( false === $fp ) {
2149                         throw new MWException( "Could not open \"{$filename}\".\n" );
2150                 }
2151                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2152                 fclose( $fp );
2153                 return $error;
2154         }
2155
2156         /**
2157          * Read and execute commands from an open file handle
2158          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2159          * @param string $fp File handle
2160          * @param callback $lineCallback Optional function called before reading each line
2161          * @param callback $resultCallback Optional function called for each MySQL result
2162          */
2163         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2164                 $cmd = "";
2165                 $done = false;
2166                 $dollarquote = false;
2167
2168                 while ( ! feof( $fp ) ) {
2169                         if ( $lineCallback ) {
2170                                 call_user_func( $lineCallback );
2171                         }
2172                         $line = trim( fgets( $fp, 1024 ) );
2173                         $sl = strlen( $line ) - 1;
2174
2175                         if ( $sl < 0 ) { continue; }
2176                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2177
2178                         ## Allow dollar quoting for function declarations
2179                         if (substr($line,0,4) == '$mw$') {
2180                                 if ($dollarquote) {
2181                                         $dollarquote = false;
2182                                         $done = true;
2183                                 }
2184                                 else {
2185                                         $dollarquote = true;
2186                                 }
2187                         }
2188                         else if (!$dollarquote) {
2189                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2190                                         $done = true;
2191                                         $line = substr( $line, 0, $sl );
2192                                 }
2193                         }
2194
2195                         if ( '' != $cmd ) { $cmd .= ' '; }
2196                         $cmd .= "$line\n";
2197
2198                         if ( $done ) {
2199                                 $cmd = str_replace(';;', ";", $cmd);
2200                                 $cmd = $this->replaceVars( $cmd );
2201                                 $res = $this->query( $cmd, __METHOD__ );
2202                                 if ( $resultCallback ) {
2203                                         call_user_func( $resultCallback, $res, $this );
2204                                 }
2205
2206                                 if ( false === $res ) {
2207                                         $err = $this->lastError();
2208                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2209                                 }
2210
2211                                 $cmd = '';
2212                                 $done = false;
2213                         }
2214                 }
2215                 return true;
2216         }
2217
2218
2219         /**
2220          * Replace variables in sourced SQL
2221          */
2222         protected function replaceVars( $ins ) {
2223                 $varnames = array(
2224                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2225                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2226                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2227                 );
2228
2229                 // Ordinary variables
2230                 foreach ( $varnames as $var ) {
2231                         if( isset( $GLOBALS[$var] ) ) {
2232                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2233                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2234                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2235                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2236                         }
2237                 }
2238
2239                 // Table prefixes
2240                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-zA-Z_0-9]*)/',
2241                         array( &$this, 'tableNameCallback' ), $ins );
2242                 return $ins;
2243         }
2244
2245         /**
2246          * Table name callback
2247          * @private
2248          */
2249         protected function tableNameCallback( $matches ) {
2250                 return $this->tableName( $matches[1] );
2251         }
2252
2253         /*
2254          * Build a concatenation list to feed into a SQL query
2255         */
2256         function buildConcat( $stringList ) {
2257                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2258         }
2259
2260         /**
2261          * Acquire a lock
2262          *
2263          * Abstracted from Filestore::lock() so child classes can implement for
2264          * their own needs.
2265          *
2266          * @param string $lockName Name of lock to aquire
2267          * @param string $method Name of method calling us
2268          * @return bool
2269          */
2270         public function lock( $lockName, $method ) {
2271                 $lockName = $this->addQuotes( $lockName );
2272                 $result = $this->query( "SELECT GET_LOCK($lockName, 5) AS lockstatus", $method );
2273                 $row = $this->fetchObject( $result );
2274                 $this->freeResult( $result );
2275
2276                 if( $row->lockstatus == 1 ) {
2277                         return true;
2278                 } else {
2279                         wfDebug( __METHOD__." failed to acquire lock\n" );
2280                         return false;
2281                 }
2282         }
2283         /**
2284          * Release a lock.
2285          *
2286          * @todo fixme - Figure out a way to return a bool
2287          * based on successful lock release.
2288          *
2289          * @param string $lockName Name of lock to release
2290          * @param string $method Name of method calling us
2291          */
2292         public function unlock( $lockName, $method ) {
2293                 $lockName = $this->addQuotes( $lockName );
2294                 $result = $this->query( "SELECT RELEASE_LOCK($lockName)", $method );
2295                 $this->freeResult( $result );
2296         }
2297
2298         /**
2299          * Get search engine class. All subclasses of this
2300          * need to implement this if they wish to use searching.
2301          *
2302          * @return string
2303          */
2304         public function getSearchEngine() {
2305                 return "SearchMySQL";
2306         }
2307 }
2308
2309 /**
2310  * Database abstraction object for mySQL
2311  * Inherit all methods and properties of Database::Database()
2312  *
2313  * @ingroup Database
2314  * @see Database
2315  */
2316 class DatabaseMysql extends Database {
2317         # Inherit all
2318 }
2319
2320 /******************************************************************************
2321  * Utility classes
2322  *****************************************************************************/
2323
2324 /**
2325  * Utility class.
2326  * @ingroup Database
2327  */
2328 class DBObject {
2329         public $mData;
2330
2331         function DBObject($data) {
2332                 $this->mData = $data;
2333         }
2334
2335         function isLOB() {
2336                 return false;
2337         }
2338
2339         function data() {
2340                 return $this->mData;
2341         }
2342 }
2343
2344 /**
2345  * Utility class
2346  * @ingroup Database
2347  *
2348  * This allows us to distinguish a blob from a normal string and an array of strings
2349  */
2350 class Blob {
2351         private $mData;
2352         function __construct($data) {
2353                 $this->mData = $data;
2354         }
2355         function fetch() {
2356                 return $this->mData;
2357         }
2358 }
2359
2360 /**
2361  * Utility class.
2362  * @ingroup Database
2363  */
2364 class MySQLField {
2365         private $name, $tablename, $default, $max_length, $nullable,
2366                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2367         function __construct ($info) {
2368                 $this->name = $info->name;
2369                 $this->tablename = $info->table;
2370                 $this->default = $info->def;
2371                 $this->max_length = $info->max_length;
2372                 $this->nullable = !$info->not_null;
2373                 $this->is_pk = $info->primary_key;
2374                 $this->is_unique = $info->unique_key;
2375                 $this->is_multiple = $info->multiple_key;
2376                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2377                 $this->type = $info->type;
2378         }
2379
2380         function name() {
2381                 return $this->name;
2382         }
2383
2384         function tableName() {
2385                 return $this->tableName;
2386         }
2387
2388         function defaultValue() {
2389                 return $this->default;
2390         }
2391
2392         function maxLength() {
2393                 return $this->max_length;
2394         }
2395
2396         function nullable() {
2397                 return $this->nullable;
2398         }
2399
2400         function isKey() {
2401                 return $this->is_key;
2402         }
2403
2404         function isMultipleKey() {
2405                 return $this->is_multiple;
2406         }
2407
2408         function type() {
2409                 return $this->type;
2410         }
2411 }
2412
2413 /******************************************************************************
2414  * Error classes
2415  *****************************************************************************/
2416
2417 /**
2418  * Database error base class
2419  * @ingroup Database
2420  */
2421 class DBError extends MWException {
2422         public $db;
2423
2424         /**
2425          * Construct a database error
2426          * @param Database $db The database object which threw the error
2427          * @param string $error A simple error message to be used for debugging
2428          */
2429         function __construct( Database &$db, $error ) {
2430                 $this->db =& $db;
2431                 parent::__construct( $error );
2432         }
2433 }
2434
2435 /**
2436  * @ingroup Database
2437  */
2438 class DBConnectionError extends DBError {
2439         public $error;
2440
2441         function __construct( Database &$db, $error = 'unknown error' ) {
2442                 $msg = 'DB connection error';
2443                 if ( trim( $error ) != '' ) {
2444                         $msg .= ": $error";
2445                 }
2446                 $this->error = $error;
2447                 parent::__construct( $db, $msg );
2448         }
2449
2450         function useOutputPage() {
2451                 // Not likely to work
2452                 return false;
2453         }
2454
2455         function useMessageCache() {
2456                 // Not likely to work
2457                 return false;
2458         }
2459
2460         function getText() {
2461                 return $this->getMessage() . "\n";
2462         }
2463
2464         function getLogMessage() {
2465                 # Don't send to the exception log
2466                 return false;
2467         }
2468
2469         function getPageTitle() {
2470                 global $wgSitename;
2471                 return "$wgSitename has a problem";
2472         }
2473
2474         function getHTML() {
2475                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
2476                 global $wgSitename, $wgServer, $wgMessageCache;
2477
2478                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
2479                 # Hard coding strings instead.
2480
2481                 $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>";
2482                 $mainpage = 'Main Page';
2483                 $searchdisabled = <<<EOT
2484 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
2485 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
2486 EOT;
2487
2488                 $googlesearch = "
2489 <!-- SiteSearch Google -->
2490 <FORM method=GET action=\"http://www.google.com/search\">
2491 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
2492 <A HREF=\"http://www.google.com/\">
2493 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
2494 border=\"0\" ALT=\"Google\"></A>
2495 </td>
2496 <td>
2497 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
2498 <INPUT type=submit name=btnG VALUE=\"Google Search\">
2499 <font size=-1>
2500 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
2501 <input type='hidden' name='ie' value='$2'>
2502 <input type='hidden' name='oe' value='$2'>
2503 </font>
2504 </td></tr></TABLE>
2505 </FORM>
2506 <!-- SiteSearch Google -->";
2507                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
2508
2509                 # No database access
2510                 if ( is_object( $wgMessageCache ) ) {
2511                         $wgMessageCache->disable();
2512                 }
2513
2514                 if ( trim( $this->error ) == '' ) {
2515                         $this->error = $this->db->getProperty('mServer');
2516                 }
2517
2518                 $text = str_replace( '$1', $this->error, $noconnect );
2519
2520                 /*
2521                 if ( $GLOBALS['wgShowExceptionDetails'] ) {
2522                         $text .= '</p><p>Backtrace:</p><p>' .
2523                                 nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
2524                                 "</p>\n";
2525                 }*/
2526
2527                 if($wgUseFileCache) {
2528                         if($wgTitle) {
2529                                 $t =& $wgTitle;
2530                         } else {
2531                                 if($title) {
2532                                         $t = Title::newFromURL( $title );
2533                                 } elseif (@/**/$_REQUEST['search']) {
2534                                         $search = $_REQUEST['search'];
2535                                         return $searchdisabled .
2536                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
2537                                           $wgInputEncoding ), $googlesearch );
2538                                 } else {
2539                                         $t = Title::newFromText( $mainpage );
2540                                 }
2541                         }
2542
2543                         $cache = new HTMLFileCache( $t );
2544                         if( $cache->isFileCached() ) {
2545                                 // @todo, FIXME: $msg is not defined on the next line.
2546                                 $msg = '<p style="color: red"><b>'.$text."<br />\n" .
2547                                         $cachederror . "</b></p>\n";
2548
2549                                 $tag = '<div id="article">';
2550                                 $text = str_replace(
2551                                         $tag,
2552                                         $tag . $text,
2553                                         $cache->fetchPageText() );
2554                         }
2555                 }
2556
2557                 return $text;
2558         }
2559 }
2560
2561 /**
2562  * @ingroup Database
2563  */
2564 class DBQueryError extends DBError {
2565         public $error, $errno, $sql, $fname;
2566
2567         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
2568                 $message = "A database error has occurred\n" .
2569                   "Query: $sql\n" .
2570                   "Function: $fname\n" .
2571                   "Error: $errno $error\n";
2572
2573                 parent::__construct( $db, $message );
2574                 $this->error = $error;
2575                 $this->errno = $errno;
2576                 $this->sql = $sql;
2577                 $this->fname = $fname;
2578         }
2579
2580         function getText() {
2581                 if ( $this->useMessageCache() ) {
2582                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2583                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2584                 } else {
2585                         return $this->getMessage();
2586                 }
2587         }
2588
2589         function getSQL() {
2590                 global $wgShowSQLErrors;
2591                 if( !$wgShowSQLErrors ) {
2592                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2593                 } else {
2594                         return $this->sql;
2595                 }
2596         }
2597
2598         function getLogMessage() {
2599                 # Don't send to the exception log
2600                 return false;
2601         }
2602
2603         function getPageTitle() {
2604                 return $this->msg( 'databaseerror', 'Database error' );
2605         }
2606
2607         function getHTML() {
2608                 if ( $this->useMessageCache() ) {
2609                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2610                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2611                 } else {
2612                         return nl2br( htmlspecialchars( $this->getMessage() ) );
2613                 }
2614         }
2615 }
2616
2617 /**
2618  * @ingroup Database
2619  */
2620 class DBUnexpectedError extends DBError {}
2621
2622
2623 /**
2624  * Result wrapper for grabbing data queried by someone else
2625  * @ingroup Database
2626  */
2627 class ResultWrapper implements Iterator {
2628         var $db, $result, $pos = 0, $currentRow = null;
2629
2630         /**
2631          * Create a new result object from a result resource and a Database object
2632          */
2633         function ResultWrapper( $database, $result ) {
2634                 $this->db = $database;
2635                 if ( $result instanceof ResultWrapper ) {
2636                         $this->result = $result->result;
2637                 } else {
2638                         $this->result = $result;
2639                 }
2640         }
2641
2642         /**
2643          * Get the number of rows in a result object
2644          */
2645         function numRows() {
2646                 return $this->db->numRows( $this->result );
2647         }
2648
2649         /**
2650          * Fetch the next row from the given result object, in object form.
2651          * Fields can be retrieved with $row->fieldname, with fields acting like
2652          * member variables.
2653          *
2654          * @param $res SQL result object as returned from Database::query(), etc.
2655          * @return MySQL row object
2656          * @throws DBUnexpectedError Thrown if the database returns an error
2657          */
2658         function fetchObject() {
2659                 return $this->db->fetchObject( $this->result );
2660         }
2661
2662         /**
2663          * Fetch the next row from the given result object, in associative array
2664          * form.  Fields are retrieved with $row['fieldname'].
2665          *
2666          * @param $res SQL result object as returned from Database::query(), etc.
2667          * @return MySQL row object
2668          * @throws DBUnexpectedError Thrown if the database returns an error
2669          */
2670         function fetchRow() {
2671                 return $this->db->fetchRow( $this->result );
2672         }
2673
2674         /**
2675          * Free a result object
2676          */
2677         function free() {
2678                 $this->db->freeResult( $this->result );
2679                 unset( $this->result );
2680                 unset( $this->db );
2681         }
2682
2683         /**
2684          * Change the position of the cursor in a result object
2685          * See mysql_data_seek()
2686          */
2687         function seek( $row ) {
2688                 $this->db->dataSeek( $this->result, $row );
2689         }
2690
2691         /*********************
2692          * Iterator functions
2693          * Note that using these in combination with the non-iterator functions
2694          * above may cause rows to be skipped or repeated.
2695          */
2696
2697         function rewind() {
2698                 if ($this->numRows()) {
2699                         $this->db->dataSeek($this->result, 0);
2700                 }
2701                 $this->pos = 0;
2702                 $this->currentRow = null;
2703         }
2704
2705         function current() {
2706                 if ( is_null( $this->currentRow ) ) {
2707                         $this->next();
2708                 }
2709                 return $this->currentRow;
2710         }
2711
2712         function key() {
2713                 return $this->pos;
2714         }
2715
2716         function next() {
2717                 $this->pos++;
2718                 $this->currentRow = $this->fetchObject();
2719                 return $this->currentRow;
2720         }
2721
2722         function valid() {
2723                 return $this->current() !== false;
2724         }
2725 }
2726
2727 class MySQLMasterPos {
2728         var $file, $pos;
2729
2730         function __construct( $file, $pos ) {
2731                 $this->file = $file;
2732                 $this->pos = $pos;
2733         }
2734
2735         function __toString() {
2736                 return "{$this->file}/{$this->pos}";
2737         }
2738 }