includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  * @package MediaWiki
   6  */
   7
   8 /** Number of times to re-try an operation in case of deadlock */
   9 define( 'DEADLOCK_TRIES', 4 );
  10 /** Minimum time to wait before retry, in microseconds */
  11 define( 'DEADLOCK_DELAY_MIN', 500000 );
  12 /** Maximum time to wait before retry */
  13 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  14
  15 /******************************************************************************
  16  * Utility classes
  17  *****************************************************************************/
  18
  19 class DBObject {
  20         public $mData;
  21
  22         function DBObject($data) {
  23                 $this->mData = $data;
  24         }
  25
  26         function isLOB() {
  27                 return false;
  28         }
  29
  30         function data() {
  31                 return $this->mData;
  32         }
  33 };
  34
  35 /******************************************************************************
  36  * Error classes
  37  *****************************************************************************/
  38
  39 /**
  40  * Database error base class
  41  */
  42 class DBError extends MWException {
  43         public $db;
  44
  45         /**
  46          * Construct a database error
  47          * @param Database $db The database object which threw the error
  48          * @param string $error A simple error message to be used for debugging
  49          */
  50         function __construct( Database &$db, $error ) {
  51                 $this->db =& $db;
  52                 parent::__construct( $error );
  53         }
  54 }
  55
  56 class DBConnectionError extends DBError {
  57         public $error;
  58
  59         function __construct( Database &$db, $error = 'unknown error' ) {
  60                 $msg = 'DB connection error';
  61                 if ( trim( $error ) != '' ) {
  62                         $msg .= ": $error";
  63                 }
  64                 $this->error = $error;
  65                 parent::__construct( $db, $msg );
  66         }
  67
  68         function useOutputPage() {
  69                 // Not likely to work
  70                 return false;
  71         }
  72
  73         function useMessageCache() {
  74                 // Not likely to work
  75                 return false;
  76         }
  77
  78         function getText() {
  79                 return $this->getMessage() . "\n";
  80         }
  81
  82         function getLogMessage() {
  83                 # Don't send to the exception log
  84                 return false;
  85         }
  86
  87         function getPageTitle() {
  88                 global $wgSitename;
  89                 return "$wgSitename has a problem";
  90         }
  91
  92         function getHTML() {
  93                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgOutputEncoding;
  94                 global $wgSitename, $wgServer, $wgMessageCache, $wgLogo;
  95
  96                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
  97                 # Hard coding strings instead.
  98
  99                 $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>";
 100                 $mainpage = 'Main Page';
 101                 $searchdisabled = <<<EOT
 102 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
 103 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
 104 EOT;
 105
 106                 $googlesearch = "
 107 <!-- SiteSearch Google -->
 108 <FORM method=GET action=\"http://www.google.com/search\">
 109 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
 110 <A HREF=\"http://www.google.com/\">
 111 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
 112 border=\"0\" ALT=\"Google\"></A>
 113 </td>
 114 <td>
 115 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
 116 <INPUT type=submit name=btnG VALUE=\"Google Search\">
 117 <font size=-1>
 118 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
 119 <input type='hidden' name='ie' value='$2'>
 120 <input type='hidden' name='oe' value='$2'>
 121 </font>
 122 </td></tr></TABLE>
 123 </FORM>
 124 <!-- SiteSearch Google -->";
 125                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
 126
 127                 # No database access
 128                 if ( is_object( $wgMessageCache ) ) {
 129                         $wgMessageCache->disable();
 130                 }
 131
 132                 if ( trim( $this->error ) == '' ) {
 133                         $this->error = $this->db->getProperty('mServer');
 134                 }
 135
 136                 $text = str_replace( '$1', $this->error, $noconnect );
 137                 $text .= wfGetSiteNotice();
 138
 139                 if($wgUseFileCache) {
 140                         if($wgTitle) {
 141                                 $t =& $wgTitle;
 142                         } else {
 143                                 if($title) {
 144                                         $t = Title::newFromURL( $title );
 145                                 } elseif (@/**/$_REQUEST['search']) {
 146                                         $search = $_REQUEST['search'];
 147                                         return $searchdisabled .
 148                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
 149                                           $wgInputEncoding ), $googlesearch );
 150                                 } else {
 151                                         $t = Title::newFromText( $mainpage );
 152                                 }
 153                         }
 154
 155                         $cache = new HTMLFileCache( $t );
 156                         if( $cache->isFileCached() ) {
 157                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
 158                                         $cachederror . "</b></p>\n";
 159
 160                                 $tag = '<div id="article">';
 161                                 $text = str_replace(
 162                                         $tag,
 163                                         $tag . $msg,
 164                                         $cache->fetchPageText() );
 165                         }
 166                 }
 167
 168                 return $text;
 169         }
 170 }
 171
 172 class DBQueryError extends DBError {
 173         public $error, $errno, $sql, $fname;
 174
 175         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
 176                 $message = "A database error has occurred\n" .
 177                   "Query: $sql\n" .
 178                   "Function: $fname\n" .
 179                   "Error: $errno $error\n";
 180
 181                 parent::__construct( $db, $message );
 182                 $this->error = $error;
 183                 $this->errno = $errno;
 184                 $this->sql = $sql;
 185                 $this->fname = $fname;
 186         }
 187
 188         function getText() {
 189                 if ( $this->useMessageCache() ) {
 190                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
 191                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
 192                 } else {
 193                         return $this->getMessage();
 194                 }
 195         }
 196
 197         function getSQL() {
 198                 global $wgShowSQLErrors;
 199                 if( !$wgShowSQLErrors ) {
 200                         return $this->msg( 'sqlhidden', 'SQL hidden' );
 201                 } else {
 202                         return $this->sql;
 203                 }
 204         }
 205
 206         function getLogMessage() {
 207                 # Don't send to the exception log
 208                 return false;
 209         }
 210
 211         function getPageTitle() {
 212                 return $this->msg( 'databaseerror', 'Database error' );
 213         }
 214
 215         function getHTML() {
 216                 if ( $this->useMessageCache() ) {
 217                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
 218                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
 219                 } else {
 220                         return nl2br( htmlspecialchars( $this->getMessage() ) );
 221                 }
 222         }
 223 }
 224
 225 class DBUnexpectedError extends DBError {}
 226
 227 /******************************************************************************/
 228
 229 /**
 230  * Database abstraction object
 231  * @package MediaWiki
 232  */
 233 class Database {
 234
 235 #------------------------------------------------------------------------------
 236 # Variables
 237 #------------------------------------------------------------------------------
 238
 239         protected $mLastQuery = '';
 240
 241         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 242         protected $mOut, $mOpened = false;
 243
 244         protected $mFailFunction;
 245         protected $mTablePrefix;
 246         protected $mFlags;
 247         protected $mTrxLevel = 0;
 248         protected $mErrorCount = 0;
 249         protected $mLBInfo = array();
 250         protected $mCascadingDeletes = false;
 251         protected $mCleanupTriggers = false;
 252         protected $mStrictIPs = false;
 253
 254 #------------------------------------------------------------------------------
 255 # Accessors
 256 #------------------------------------------------------------------------------
 257         # These optionally set a variable and return the previous state
 258
 259         /**
 260          * Fail function, takes a Database as a parameter
 261          * Set to false for default, 1 for ignore errors
 262          */
 263         function failFunction( $function = NULL ) {
 264                 return wfSetVar( $this->mFailFunction, $function );
 265         }
 266
 267         /**
 268          * Output page, used for reporting errors
 269          * FALSE means discard output
 270          */
 271         function setOutputPage( $out ) {
 272                 $this->mOut = $out;
 273         }
 274
 275         /**
 276          * Boolean, controls output of large amounts of debug information
 277          */
 278         function debug( $debug = NULL ) {
 279                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
 280         }
 281
 282         /**
 283          * Turns buffering of SQL result sets on (true) or off (false).
 284          * Default is "on" and it should not be changed without good reasons.
 285          */
 286         function bufferResults( $buffer = NULL ) {
 287                 if ( is_null( $buffer ) ) {
 288                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 289                 } else {
 290                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 291                 }
 292         }
 293
 294         /**
 295          * Turns on (false) or off (true) the automatic generation and sending
 296          * of a "we're sorry, but there has been a database error" page on
 297          * database errors. Default is on (false). When turned off, the
 298          * code should use wfLastErrno() and wfLastError() to handle the
 299          * situation as appropriate.
 300          */
 301         function ignoreErrors( $ignoreErrors = NULL ) {
 302                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 303         }
 304
 305         /**
 306          * The current depth of nested transactions
 307          * @param $level Integer: , default NULL.
 308          */
 309         function trxLevel( $level = NULL ) {
 310                 return wfSetVar( $this->mTrxLevel, $level );
 311         }
 312
 313         /**
 314          * Number of errors logged, only useful when errors are ignored
 315          */
 316         function errorCount( $count = NULL ) {
 317                 return wfSetVar( $this->mErrorCount, $count );
 318         }
 319
 320         /**
 321          * Properties passed down from the server info array of the load balancer
 322          */
 323         function getLBInfo( $name = NULL ) {
 324                 if ( is_null( $name ) ) {
 325                         return $this->mLBInfo;
 326                 } else {
 327                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 328                                 return $this->mLBInfo[$name];
 329                         } else {
 330                                 return NULL;
 331                         }
 332                 }
 333         }
 334
 335         function setLBInfo( $name, $value = NULL ) {
 336                 if ( is_null( $value ) ) {
 337                         $this->mLBInfo = $name;
 338                 } else {
 339                         $this->mLBInfo[$name] = $value;
 340                 }
 341         }
 342
 343         /**
 344          * Returns true if this database supports (and uses) cascading deletes
 345          */
 346         function cascadingDeletes() {
 347                 return $this->mCascadingDeletes;
 348         }
 349
 350         /**
 351          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 352          */
 353         function cleanupTriggers() {
 354                 return $this->mCleanupTriggers;
 355         }
 356
 357         /**
 358          * Returns true if this database is strict about what can be put into an IP field.
 359          * Specifically, it uses a NULL value instead of an empty string.
 360          */
 361         function strictIPs() {
 362                 return $this->mStrictIPs;
 363         }
 364
 365         /**#@+
 366          * Get function
 367          */
 368         function lastQuery() { return $this->mLastQuery; }
 369         function isOpen() { return $this->mOpened; }
 370         /**#@-*/
 371
 372         function setFlag( $flag ) {
 373                 $this->mFlags |= $flag;
 374         }
 375
 376         function clearFlag( $flag ) {
 377                 $this->mFlags &= ~$flag;
 378         }
 379
 380         function getFlag( $flag ) {
 381                 return !!($this->mFlags & $flag);
 382         }
 383
 384         /**
 385          * General read-only accessor
 386          */
 387         function getProperty( $name ) {
 388                 return $this->$name;
 389         }
 390
 391 #------------------------------------------------------------------------------
 392 # Other functions
 393 #------------------------------------------------------------------------------
 394
 395         /**@{{
 396          * @param string $server database server host
 397          * @param string $user database user name
 398          * @param string $password database user password
 399          * @param string $dbname database name
 400          */
 401
 402         /**
 403          * @param failFunction
 404          * @param $flags
 405          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 406          */
 407         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 408                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 409
 410                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 411                 # Can't get a reference if it hasn't been set yet
 412                 if ( !isset( $wgOut ) ) {
 413                         $wgOut = NULL;
 414                 }
 415                 $this->mOut =& $wgOut;
 416
 417                 $this->mFailFunction = $failFunction;
 418                 $this->mFlags = $flags;
 419
 420                 if ( $this->mFlags & DBO_DEFAULT ) {
 421                         if ( $wgCommandLineMode ) {
 422                                 $this->mFlags &= ~DBO_TRX;
 423                         } else {
 424                                 $this->mFlags |= DBO_TRX;
 425                         }
 426                 }
 427
 428                 /*
 429                 // Faster read-only access
 430                 if ( wfReadOnly() ) {
 431                         $this->mFlags |= DBO_PERSISTENT;
 432                         $this->mFlags &= ~DBO_TRX;
 433                 }*/
 434
 435                 /** Get the default table prefix*/
 436                 if ( $tablePrefix == 'get from global' ) {
 437                         $this->mTablePrefix = $wgDBprefix;
 438                 } else {
 439                         $this->mTablePrefix = $tablePrefix;
 440                 }
 441
 442                 if ( $server ) {
 443                         $this->open( $server, $user, $password, $dbName );
 444                 }
 445         }
 446
 447         /**
 448          * @static
 449          * @param failFunction
 450          * @param $flags
 451          */
 452         static function newFromParams( $server, $user, $password, $dbName,
 453                 $failFunction = false, $flags = 0 )
 454         {
 455                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 456         }
 457
 458         /**
 459          * Usually aborts on failure
 460          * If the failFunction is set to a non-zero integer, returns success
 461          */
 462         function open( $server, $user, $password, $dbName ) {
 463                 global $wguname;
 464                 wfProfileIn( __METHOD__ );
 465
 466                 # Test for missing mysql.so
 467                 # First try to load it
 468                 if (!@extension_loaded('mysql')) {
 469                         @dl('mysql.so');
 470                 }
 471
 472                 # Fail now
 473                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 474                 if ( !function_exists( 'mysql_connect' ) ) {
 475                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 476                 }
 477
 478                 $this->close();
 479                 $this->mServer = $server;
 480                 $this->mUser = $user;
 481                 $this->mPassword = $password;
 482                 $this->mDBname = $dbName;
 483
 484                 $success = false;
 485
 486                 wfProfileIn("dbconnect-$server");
 487
 488                 # LIVE PATCH by Tim, ask Domas for why: retry loop
 489                 $this->mConn = false;
 490                 $max = 3;
 491                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 492                         if ( $i > 1 ) {
 493                                 usleep( 1000 );
 494                         }
 495                         if ( $this->mFlags & DBO_PERSISTENT ) {
 496                                 @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 497                         } else {
 498                                 # Create a new connection...
 499                                 @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 500                         }
 501                         if ($this->mConn === false) {
 502                                 $iplus = $i + 1;
 503                                 wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 504                         }
 505                 }
 506
 507                 wfProfileOut("dbconnect-$server");
 508
 509                 if ( $dbName != '' ) {
 510                         if ( $this->mConn !== false ) {
 511                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 512                                 if ( !$success ) {
 513                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 514                                                 "from client host {$wguname['nodename']}\n";
 515                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 516                                         wfDebug( $error );
 517                                 }
 518                         } else {
 519                                 wfDebug( "DB connection error\n" );
 520                                 wfDebug( "Server: $server, User: $user, Password: " .
 521                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 522                                 $success = false;
 523                         }
 524                 } else {
 525                         # Delay USE query
 526                         $success = (bool)$this->mConn;
 527                 }
 528
 529                 if ( $success ) {
 530                         global $wgDBmysql5;
 531                         if( $wgDBmysql5 ) {
 532                                 // Tell the server we're communicating with it in UTF-8.
 533                                 // This may engage various charset conversions.
 534                                 $this->query( 'SET NAMES utf8' );
 535                         }
 536                 } else {
 537                         $this->reportConnectionError();
 538                 }
 539
 540                 $this->mOpened = $success;
 541                 wfProfileOut( __METHOD__ );
 542                 return $success;
 543         }
 544         /**@}}*/
 545
 546         /**
 547          * Closes a database connection.
 548          * if it is open : commits any open transactions
 549          *
 550          * @return bool operation success. true if already closed.
 551          */
 552         function close()
 553         {
 554                 $this->mOpened = false;
 555                 if ( $this->mConn ) {
 556                         if ( $this->trxLevel() ) {
 557                                 $this->immediateCommit();
 558                         }
 559                         return mysql_close( $this->mConn );
 560                 } else {
 561                         return true;
 562                 }
 563         }
 564
 565         /**
 566          * @param string $error fallback error message, used if none is given by MySQL
 567          */
 568         function reportConnectionError( $error = 'Unknown error' ) {
 569                 $myError = $this->lastError();
 570                 if ( $myError ) {
 571                         $error = $myError;
 572                 }
 573
 574                 if ( $this->mFailFunction ) {
 575                         # Legacy error handling method
 576                         if ( !is_int( $this->mFailFunction ) ) {
 577                                 $ff = $this->mFailFunction;
 578                                 $ff( $this, $error );
 579                         }
 580                 } else {
 581                         # New method
 582                         wfLogDBError( "Connection error: $error\n" );
 583                         throw new DBConnectionError( $this, $error );
 584                 }
 585         }
 586
 587         /**
 588          * Usually aborts on failure
 589          * If errors are explicitly ignored, returns success
 590          */
 591         function query( $sql, $fname = '', $tempIgnore = false ) {
 592                 global $wgProfiling;
 593
 594                 if ( $wgProfiling ) {
 595                         # generalizeSQL will probably cut down the query to reasonable
 596                         # logging size most of the time. The substr is really just a sanity check.
 597
 598                         # Who's been wasting my precious column space? -- TS
 599                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 600
 601                         if ( is_null( $this->getLBInfo( 'master' ) ) ) {
 602                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 603                                 $totalProf = 'Database::query';
 604                         } else {
 605                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 606                                 $totalProf = 'Database::query-master';
 607                         }
 608                         wfProfileIn( $totalProf );
 609                         wfProfileIn( $queryProf );
 610                 }
 611
 612                 $this->mLastQuery = $sql;
 613
 614                 # Add a comment for easy SHOW PROCESSLIST interpretation
 615                 if ( $fname ) {
 616                         $commentedSql = preg_replace("/\s/", " /* $fname */ ", $sql, 1);
 617                 } else {
 618                         $commentedSql = $sql;
 619                 }
 620
 621                 # If DBO_TRX is set, start a transaction
 622                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 623                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK'
 624                 ) {
 625                         $this->begin();
 626                 }
 627
 628                 if ( $this->debug() ) {
 629                         $sqlx = substr( $commentedSql, 0, 500 );
 630                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 631                         wfDebug( "SQL: $sqlx\n" );
 632                 }
 633
 634                 # Do the query and handle errors
 635                 $ret = $this->doQuery( $commentedSql );
 636
 637                 # Try reconnecting if the connection was lost
 638                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 639                         # Transaction is gone, like it or not
 640                         $this->mTrxLevel = 0;
 641                         wfDebug( "Connection lost, reconnecting...\n" );
 642                         if ( $this->ping() ) {
 643                                 wfDebug( "Reconnected\n" );
 644                                 $ret = $this->doQuery( $commentedSql );
 645                         } else {
 646                                 wfDebug( "Failed\n" );
 647                         }
 648                 }
 649
 650                 if ( false === $ret ) {
 651                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 652                 }
 653
 654                 if ( $wgProfiling ) {
 655                         wfProfileOut( $queryProf );
 656                         wfProfileOut( $totalProf );
 657                 }
 658                 return $ret;
 659         }
 660
 661         /**
 662          * The DBMS-dependent part of query()
 663          * @param string $sql SQL query.
 664          */
 665         function doQuery( $sql ) {
 666                 if( $this->bufferResults() ) {
 667                         $ret = mysql_query( $sql, $this->mConn );
 668                 } else {
 669                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 670                 }
 671                 return $ret;
 672         }
 673
 674         /**
 675          * @param $error
 676          * @param $errno
 677          * @param $sql
 678          * @param string $fname
 679          * @param bool $tempIgnore
 680          */
 681         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 682                 global $wgCommandLineMode, $wgFullyInitialised, $wgColorErrors;
 683                 # Ignore errors during error handling to avoid infinite recursion
 684                 $ignore = $this->ignoreErrors( true );
 685                 ++$this->mErrorCount;
 686
 687                 if( $ignore || $tempIgnore ) {
 688                         wfDebug("SQL ERROR (ignored): $error\n");
 689                         $this->ignoreErrors( $ignore );
 690                 } else {
 691                         $sql1line = str_replace( "\n", "\\n", $sql );
 692                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 693                         wfDebug("SQL ERROR: " . $error . "\n");
 694                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 695                 }
 696         }
 697
 698
 699         /**
 700          * Intended to be compatible with the PEAR::DB wrapper functions.
 701          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 702          *
 703          * ? = scalar value, quoted as necessary
 704          * ! = raw SQL bit (a function for instance)
 705          * & = filename; reads the file and inserts as a blob
 706          *     (we don't use this though...)
 707          */
 708         function prepare( $sql, $func = 'Database::prepare' ) {
 709                 /* MySQL doesn't support prepared statements (yet), so just
 710                    pack up the query for reference. We'll manually replace
 711                    the bits later. */
 712                 return array( 'query' => $sql, 'func' => $func );
 713         }
 714
 715         function freePrepared( $prepared ) {
 716                 /* No-op for MySQL */
 717         }
 718
 719         /**
 720          * Execute a prepared query with the various arguments
 721          * @param string $prepared the prepared sql
 722          * @param mixed $args Either an array here, or put scalars as varargs
 723          */
 724         function execute( $prepared, $args = null ) {
 725                 if( !is_array( $args ) ) {
 726                         # Pull the var args
 727                         $args = func_get_args();
 728                         array_shift( $args );
 729                 }
 730                 $sql = $this->fillPrepared( $prepared['query'], $args );
 731                 return $this->query( $sql, $prepared['func'] );
 732         }
 733
 734         /**
 735          * Prepare & execute an SQL statement, quoting and inserting arguments
 736          * in the appropriate places.
 737          * @param string $query
 738          * @param string $args ...
 739          */
 740         function safeQuery( $query, $args = null ) {
 741                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 742                 if( !is_array( $args ) ) {
 743                         # Pull the var args
 744                         $args = func_get_args();
 745                         array_shift( $args );
 746                 }
 747                 $retval = $this->execute( $prepared, $args );
 748                 $this->freePrepared( $prepared );
 749                 return $retval;
 750         }
 751
 752         /**
 753          * For faking prepared SQL statements on DBs that don't support
 754          * it directly.
 755          * @param string $preparedSql - a 'preparable' SQL statement
 756          * @param array $args - array of arguments to fill it with
 757          * @return string executable SQL
 758          */
 759         function fillPrepared( $preparedQuery, $args ) {
 760                 reset( $args );
 761                 $this->preparedArgs =& $args;
 762                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 763                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 764         }
 765
 766         /**
 767          * preg_callback func for fillPrepared()
 768          * The arguments should be in $this->preparedArgs and must not be touched
 769          * while we're doing this.
 770          *
 771          * @param array $matches
 772          * @return string
 773          * @private
 774          */
 775         function fillPreparedArg( $matches ) {
 776                 switch( $matches[1] ) {
 777                         case '\\?': return '?';
 778                         case '\\!': return '!';
 779                         case '\\&': return '&';
 780                 }
 781                 list( $n, $arg ) = each( $this->preparedArgs );
 782                 switch( $matches[1] ) {
 783                         case '?': return $this->addQuotes( $arg );
 784                         case '!': return $arg;
 785                         case '&':
 786                                 # return $this->addQuotes( file_get_contents( $arg ) );
 787                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 788                         default:
 789                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 790                 }
 791         }
 792
 793         /**#@+
 794          * @param mixed $res A SQL result
 795          */
 796         /**
 797          * Free a result object
 798          */
 799         function freeResult( $res ) {
 800                 if ( !@/**/mysql_free_result( $res ) ) {
 801                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 802                 }
 803         }
 804
 805         /**
 806          * Fetch the next row from the given result object, in object form
 807          */
 808         function fetchObject( $res ) {
 809                 @/**/$row = mysql_fetch_object( $res );
 810                 if( $this->lastErrno() ) {
 811                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 812                 }
 813                 return $row;
 814         }
 815
 816         /**
 817          * Fetch the next row from the given result object
 818          * Returns an array
 819          */
 820         function fetchRow( $res ) {
 821                 @/**/$row = mysql_fetch_array( $res );
 822                 if ( $this->lastErrno() ) {
 823                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 824                 }
 825                 return $row;
 826         }
 827
 828         /**
 829          * Get the number of rows in a result object
 830          */
 831         function numRows( $res ) {
 832                 @/**/$n = mysql_num_rows( $res );
 833                 if( $this->lastErrno() ) {
 834                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 835                 }
 836                 return $n;
 837         }
 838
 839         /**
 840          * Get the number of fields in a result object
 841          * See documentation for mysql_num_fields()
 842          */
 843         function numFields( $res ) { return mysql_num_fields( $res ); }
 844
 845         /**
 846          * Get a field name in a result object
 847          * See documentation for mysql_field_name():
 848          * http://www.php.net/mysql_field_name
 849          */
 850         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 851
 852         /**
 853          * Get the inserted value of an auto-increment row
 854          *
 855          * The value inserted should be fetched from nextSequenceValue()
 856          *
 857          * Example:
 858          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 859          * $dbw->insert('page',array('page_id' => $id));
 860          * $id = $dbw->insertId();
 861          */
 862         function insertId() { return mysql_insert_id( $this->mConn ); }
 863
 864         /**
 865          * Change the position of the cursor in a result object
 866          * See mysql_data_seek()
 867          */
 868         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 869
 870         /**
 871          * Get the last error number
 872          * See mysql_errno()
 873          */
 874         function lastErrno() {
 875                 if ( $this->mConn ) {
 876                         return mysql_errno( $this->mConn );
 877                 } else {
 878                         return mysql_errno();
 879                 }
 880         }
 881
 882         /**
 883          * Get a description of the last error
 884          * See mysql_error() for more details
 885          */
 886         function lastError() {
 887                 if ( $this->mConn ) {
 888                         # Even if it's non-zero, it can still be invalid
 889                         wfSuppressWarnings();
 890                         $error = mysql_error( $this->mConn );
 891                         if ( !$error ) {
 892                                 $error = mysql_error();
 893                         }
 894                         wfRestoreWarnings();
 895                 } else {
 896                         $error = mysql_error();
 897                 }
 898                 if( $error ) {
 899                         $error .= ' (' . $this->mServer . ')';
 900                 }
 901                 return $error;
 902         }
 903         /**
 904          * Get the number of rows affected by the last write query
 905          * See mysql_affected_rows() for more details
 906          */
 907         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 908         /**#@-*/ // end of template : @param $result
 909
 910         /**
 911          * Simple UPDATE wrapper
 912          * Usually aborts on failure
 913          * If errors are explicitly ignored, returns success
 914          *
 915          * This function exists for historical reasons, Database::update() has a more standard
 916          * calling convention and feature set
 917          */
 918         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 919         {
 920                 $table = $this->tableName( $table );
 921                 $sql = "UPDATE $table SET $var = '" .
 922                   $this->strencode( $value ) . "' WHERE ($cond)";
 923                 return (bool)$this->query( $sql, $fname );
 924         }
 925
 926         /**
 927          * Simple SELECT wrapper, returns a single field, input must be encoded
 928          * Usually aborts on failure
 929          * If errors are explicitly ignored, returns FALSE on failure
 930          */
 931         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 932                 if ( !is_array( $options ) ) {
 933                         $options = array( $options );
 934                 }
 935                 $options['LIMIT'] = 1;
 936
 937                 $res = $this->select( $table, $var, $cond, $fname, $options );
 938                 if ( $res === false || !$this->numRows( $res ) ) {
 939                         return false;
 940                 }
 941                 $row = $this->fetchRow( $res );
 942                 if ( $row !== false ) {
 943                         $this->freeResult( $res );
 944                         return $row[0];
 945                 } else {
 946                         return false;
 947                 }
 948         }
 949
 950         /**
 951          * Returns an optional USE INDEX clause to go after the table, and a
 952          * string to go at the end of the query
 953          *
 954          * @private
 955          *
 956          * @param array $options an associative array of options to be turned into
 957          *              an SQL query, valid keys are listed in the function.
 958          * @return array
 959          */
 960         function makeSelectOptions( $options ) {
 961                 $tailOpts = '';
 962                 $startOpts = '';
 963
 964                 $noKeyOptions = array();
 965                 foreach ( $options as $key => $option ) {
 966                         if ( is_numeric( $key ) ) {
 967                                 $noKeyOptions[$option] = true;
 968                         }
 969                 }
 970
 971                 if ( isset( $options['GROUP BY'] ) ) $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 972                 if ( isset( $options['ORDER BY'] ) ) $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 973
 974                 if (isset($options['LIMIT'])) {
 975                         $tailOpts .= $this->limitResult('', $options['LIMIT'],
 976                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 977                 }
 978
 979                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $tailOpts .= ' FOR UPDATE';
 980                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $tailOpts .= ' LOCK IN SHARE MODE';
 981                 if ( isset( $noKeyOptions['DISTINCT'] ) && isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 982
 983                 # Various MySQL extensions
 984                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 985                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 986                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 987                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 988                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 989                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 990                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 991                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 992
 993                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 994                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 995                 } else {
 996                         $useIndex = '';
 997                 }
 998
 999                 return array( $startOpts, $useIndex, $tailOpts );
1000         }
1001
1002         /**
1003          * SELECT wrapper
1004          */
1005         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
1006         {
1007                 if( is_array( $vars ) ) {
1008                         $vars = implode( ',', $vars );
1009                 }
1010                 if( !is_array( $options ) ) {
1011                         $options = array( $options );
1012                 }
1013                 if( is_array( $table ) ) {
1014                         if ( @is_array( $options['USE INDEX'] ) )
1015                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
1016                         else
1017                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1018                 } elseif ($table!='') {
1019                         $from = ' FROM ' . $this->tableName( $table );
1020                 } else {
1021                         $from = '';
1022                 }
1023
1024                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $options );
1025
1026                 if( !empty( $conds ) ) {
1027                         if ( is_array( $conds ) ) {
1028                                 $conds = $this->makeList( $conds, LIST_AND );
1029                         }
1030                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $tailOpts";
1031                 } else {
1032                         $sql = "SELECT $startOpts $vars $from $useIndex $tailOpts";
1033                 }
1034
1035                 return $this->query( $sql, $fname );
1036         }
1037
1038         /**
1039          * Single row SELECT wrapper
1040          * Aborts or returns FALSE on error
1041          *
1042          * $vars: the selected variables
1043          * $conds: a condition map, terms are ANDed together.
1044          *   Items with numeric keys are taken to be literal conditions
1045          * Takes an array of selected variables, and a condition map, which is ANDed
1046          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1047          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1048          * $obj- >page_id is the ID of the Astronomy article
1049          *
1050          * @todo migrate documentation to phpdocumentor format
1051          */
1052         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
1053                 $options['LIMIT'] = 1;
1054                 $res = $this->select( $table, $vars, $conds, $fname, $options );
1055                 if ( $res === false )
1056                         return false;
1057                 if ( !$this->numRows($res) ) {
1058                         $this->freeResult($res);
1059                         return false;
1060                 }
1061                 $obj = $this->fetchObject( $res );
1062                 $this->freeResult( $res );
1063                 return $obj;
1064
1065         }
1066
1067         /**
1068          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1069          * It's only slightly flawed. Don't use for anything important.
1070          *
1071          * @param string $sql A SQL Query
1072          * @static
1073          */
1074         static function generalizeSQL( $sql ) {
1075                 # This does the same as the regexp below would do, but in such a way
1076                 # as to avoid crashing php on some large strings.
1077                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1078
1079                 $sql = str_replace ( "\\\\", '', $sql);
1080                 $sql = str_replace ( "\\'", '', $sql);
1081                 $sql = str_replace ( "\\\"", '', $sql);
1082                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1083                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1084
1085                 # All newlines, tabs, etc replaced by single space
1086                 $sql = preg_replace ( "/\s+/", ' ', $sql);
1087
1088                 # All numbers => N
1089                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1090
1091                 return $sql;
1092         }
1093
1094         /**
1095          * Determines whether a field exists in a table
1096          * Usually aborts on failure
1097          * If errors are explicitly ignored, returns NULL on failure
1098          */
1099         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1100                 $table = $this->tableName( $table );
1101                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1102                 if ( !$res ) {
1103                         return NULL;
1104                 }
1105
1106                 $found = false;
1107
1108                 while ( $row = $this->fetchObject( $res ) ) {
1109                         if ( $row->Field == $field ) {
1110                                 $found = true;
1111                                 break;
1112                         }
1113                 }
1114                 return $found;
1115         }
1116
1117         /**
1118          * Determines whether an index exists
1119          * Usually aborts on failure
1120          * If errors are explicitly ignored, returns NULL on failure
1121          */
1122         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1123                 $info = $this->indexInfo( $table, $index, $fname );
1124                 if ( is_null( $info ) ) {
1125                         return NULL;
1126                 } else {
1127                         return $info !== false;
1128                 }
1129         }
1130
1131
1132         /**
1133          * Get information about an index into an object
1134          * Returns false if the index does not exist
1135          */
1136         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1137                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1138                 # SHOW INDEX should work for 3.x and up:
1139                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1140                 $table = $this->tableName( $table );
1141                 $sql = 'SHOW INDEX FROM '.$table;
1142                 $res = $this->query( $sql, $fname );
1143                 if ( !$res ) {
1144                         return NULL;
1145                 }
1146
1147                 $result = array();
1148                 while ( $row = $this->fetchObject( $res ) ) {
1149                         if ( $row->Key_name == $index ) {
1150                                 $result[] = $row;
1151                         }
1152                 }
1153                 $this->freeResult($res);
1154
1155                 return empty($result) ? false : $result;
1156         }
1157
1158         /**
1159          * Query whether a given table exists
1160          */
1161         function tableExists( $table ) {
1162                 $table = $this->tableName( $table );
1163                 $old = $this->ignoreErrors( true );
1164                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1165                 $this->ignoreErrors( $old );
1166                 if( $res ) {
1167                         $this->freeResult( $res );
1168                         return true;
1169                 } else {
1170                         return false;
1171                 }
1172         }
1173
1174         /**
1175          * mysql_fetch_field() wrapper
1176          * Returns false if the field doesn't exist
1177          *
1178          * @param $table
1179          * @param $field
1180          */
1181         function fieldInfo( $table, $field ) {
1182                 $table = $this->tableName( $table );
1183                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1184                 $n = mysql_num_fields( $res );
1185                 for( $i = 0; $i < $n; $i++ ) {
1186                         $meta = mysql_fetch_field( $res, $i );
1187                         if( $field == $meta->name ) {
1188                                 return $meta;
1189                         }
1190                 }
1191                 return false;
1192         }
1193
1194         /**
1195          * mysql_field_type() wrapper
1196          */
1197         function fieldType( $res, $index ) {
1198                 return mysql_field_type( $res, $index );
1199         }
1200
1201         /**
1202          * Determines if a given index is unique
1203          */
1204         function indexUnique( $table, $index ) {
1205                 $indexInfo = $this->indexInfo( $table, $index );
1206                 if ( !$indexInfo ) {
1207                         return NULL;
1208                 }
1209                 return !$indexInfo[0]->Non_unique;
1210         }
1211
1212         /**
1213          * INSERT wrapper, inserts an array into a table
1214          *
1215          * $a may be a single associative array, or an array of these with numeric keys, for
1216          * multi-row insert.
1217          *
1218          * Usually aborts on failure
1219          * If errors are explicitly ignored, returns success
1220          */
1221         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1222                 # No rows to insert, easy just return now
1223                 if ( !count( $a ) ) {
1224                         return true;
1225                 }
1226
1227                 $table = $this->tableName( $table );
1228                 if ( !is_array( $options ) ) {
1229                         $options = array( $options );
1230                 }
1231                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1232                         $multi = true;
1233                         $keys = array_keys( $a[0] );
1234                 } else {
1235                         $multi = false;
1236                         $keys = array_keys( $a );
1237                 }
1238
1239                 $sql = 'INSERT ' . implode( ' ', $options ) .
1240                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1241
1242                 if ( $multi ) {
1243                         $first = true;
1244                         foreach ( $a as $row ) {
1245                                 if ( $first ) {
1246                                         $first = false;
1247                                 } else {
1248                                         $sql .= ',';
1249                                 }
1250                                 $sql .= '(' . $this->makeList( $row ) . ')';
1251                         }
1252                 } else {
1253                         $sql .= '(' . $this->makeList( $a ) . ')';
1254                 }
1255                 return (bool)$this->query( $sql, $fname );
1256         }
1257
1258         /**
1259          * Make UPDATE options for the Database::update function
1260          *
1261          * @private
1262          * @param array $options The options passed to Database::update
1263          * @return string
1264          */
1265         function makeUpdateOptions( $options ) {
1266                 if( !is_array( $options ) ) {
1267                         $options = array( $options );
1268                 }
1269                 $opts = array();
1270                 if ( in_array( 'LOW_PRIORITY', $options ) )
1271                         $opts[] = $this->lowPriorityOption();
1272                 if ( in_array( 'IGNORE', $options ) )
1273                         $opts[] = 'IGNORE';
1274                 return implode(' ', $opts);
1275         }
1276
1277         /**
1278          * UPDATE wrapper, takes a condition array and a SET array
1279          *
1280          * @param string $table  The table to UPDATE
1281          * @param array  $values An array of values to SET
1282          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1283          * @param string $fname  The Class::Function calling this function
1284          *                       (for the log)
1285          * @param array  $options An array of UPDATE options, can be one or
1286          *                        more of IGNORE, LOW_PRIORITY
1287          */
1288         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1289                 $table = $this->tableName( $table );
1290                 $opts = $this->makeUpdateOptions( $options );
1291                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1292                 if ( $conds != '*' ) {
1293                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1294                 }
1295                 $this->query( $sql, $fname );
1296         }
1297
1298         /**
1299          * Makes a wfStrencoded list from an array
1300          * $mode:
1301          *        LIST_COMMA         - comma separated, no field names
1302          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1303          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1304          *        LIST_SET           - comma separated with field names, like a SET clause
1305          *        LIST_NAMES         - comma separated field names
1306          */
1307         function makeList( $a, $mode = LIST_COMMA ) {
1308                 if ( !is_array( $a ) ) {
1309                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1310                 }
1311
1312                 $first = true;
1313                 $list = '';
1314                 foreach ( $a as $field => $value ) {
1315                         if ( !$first ) {
1316                                 if ( $mode == LIST_AND ) {
1317                                         $list .= ' AND ';
1318                                 } elseif($mode == LIST_OR) {
1319                                         $list .= ' OR ';
1320                                 } else {
1321                                         $list .= ',';
1322                                 }
1323                         } else {
1324                                 $first = false;
1325                         }
1326                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1327                                 $list .= "($value)";
1328                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array ($value) ) {
1329                                 $list .= $field." IN (".$this->makeList($value).") ";
1330                         } else {
1331                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1332                                         $list .= "$field = ";
1333                                 }
1334                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1335                         }
1336                 }
1337                 return $list;
1338         }
1339
1340         /**
1341          * Change the current database
1342          */
1343         function selectDB( $db ) {
1344                 $this->mDBname = $db;
1345                 return mysql_select_db( $db, $this->mConn );
1346         }
1347
1348         /**
1349          * Format a table name ready for use in constructing an SQL query
1350          *
1351          * This does two important things: it quotes table names which as necessary,
1352          * and it adds a table prefix if there is one.
1353          *
1354          * All functions of this object which require a table name call this function
1355          * themselves. Pass the canonical name to such functions. This is only needed
1356          * when calling query() directly.
1357          *
1358          * @param string $name database table name
1359          */
1360         function tableName( $name ) {
1361                 global $wgSharedDB;
1362                 # Skip quoted literals
1363                 if ( $name{0} != '`' ) {
1364                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1365                                 $name = "{$this->mTablePrefix}$name";
1366                         }
1367                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1368                                 $name = "`$wgSharedDB`.`$name`";
1369                         } else {
1370                                 # Standard quoting
1371                                 $name = "`$name`";
1372                         }
1373                 }
1374                 return $name;
1375         }
1376
1377         /**
1378          * Fetch a number of table names into an array
1379          * This is handy when you need to construct SQL for joins
1380          *
1381          * Example:
1382          * extract($dbr->tableNames('user','watchlist'));
1383          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1384          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1385          */
1386         function tableNames() {
1387                 $inArray = func_get_args();
1388                 $retVal = array();
1389                 foreach ( $inArray as $name ) {
1390                         $retVal[$name] = $this->tableName( $name );
1391                 }
1392                 return $retVal;
1393         }
1394
1395         /**
1396          * @private
1397          */
1398         function tableNamesWithUseIndex( $tables, $use_index ) {
1399                 $ret = array();
1400
1401                 foreach ( $tables as $table )
1402                         if ( @$use_index[$table] !== null )
1403                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1404                         else
1405                                 $ret[] = $this->tableName( $table );
1406
1407                 return implode( ',', $ret );
1408         }
1409
1410         /**
1411          * Wrapper for addslashes()
1412          * @param string $s String to be slashed.
1413          * @return string slashed string.
1414          */
1415         function strencode( $s ) {
1416                 return mysql_real_escape_string( $s, $this->mConn );
1417         }
1418
1419         /**
1420          * If it's a string, adds quotes and backslashes
1421          * Otherwise returns as-is
1422          */
1423         function addQuotes( $s ) {
1424                 if ( is_null( $s ) ) {
1425                         return 'NULL';
1426                 } else {
1427                         # This will also quote numeric values. This should be harmless,
1428                         # and protects against weird problems that occur when they really
1429                         # _are_ strings such as article titles and string->number->string
1430                         # conversion is not 1:1.
1431                         return "'" . $this->strencode( $s ) . "'";
1432                 }
1433         }
1434
1435         /**
1436          * Escape string for safe LIKE usage
1437          */
1438         function escapeLike( $s ) {
1439                 $s=$this->strencode( $s );
1440                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1441                 return $s;
1442         }
1443
1444         /**
1445          * Returns an appropriately quoted sequence value for inserting a new row.
1446          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1447          * subclass will return an integer, and save the value for insertId()
1448          */
1449         function nextSequenceValue( $seqName ) {
1450                 return NULL;
1451         }
1452
1453         /**
1454          * USE INDEX clause
1455          * PostgreSQL doesn't have them and returns ""
1456          */
1457         function useIndexClause( $index ) {
1458                 return "FORCE INDEX ($index)";
1459         }
1460
1461         /**
1462          * REPLACE query wrapper
1463          * PostgreSQL simulates this with a DELETE followed by INSERT
1464          * $row is the row to insert, an associative array
1465          * $uniqueIndexes is an array of indexes. Each element may be either a
1466          * field name or an array of field names
1467          *
1468          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1469          * However if you do this, you run the risk of encountering errors which wouldn't have
1470          * occurred in MySQL
1471          *
1472          * @todo migrate comment to phodocumentor format
1473          */
1474         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1475                 $table = $this->tableName( $table );
1476
1477                 # Single row case
1478                 if ( !is_array( reset( $rows ) ) ) {
1479                         $rows = array( $rows );
1480                 }
1481
1482                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1483                 $first = true;
1484                 foreach ( $rows as $row ) {
1485                         if ( $first ) {
1486                                 $first = false;
1487                         } else {
1488                                 $sql .= ',';
1489                         }
1490                         $sql .= '(' . $this->makeList( $row ) . ')';
1491                 }
1492                 return $this->query( $sql, $fname );
1493         }
1494
1495         /**
1496          * DELETE where the condition is a join
1497          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1498          *
1499          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1500          * join condition matches, set $conds='*'
1501          *
1502          * DO NOT put the join condition in $conds
1503          *
1504          * @param string $delTable The table to delete from.
1505          * @param string $joinTable The other table.
1506          * @param string $delVar The variable to join on, in the first table.
1507          * @param string $joinVar The variable to join on, in the second table.
1508          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1509          */
1510         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1511                 if ( !$conds ) {
1512                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1513                 }
1514
1515                 $delTable = $this->tableName( $delTable );
1516                 $joinTable = $this->tableName( $joinTable );
1517                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1518                 if ( $conds != '*' ) {
1519                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1520                 }
1521
1522                 return $this->query( $sql, $fname );
1523         }
1524
1525         /**
1526          * Returns the size of a text field, or -1 for "unlimited"
1527          */
1528         function textFieldSize( $table, $field ) {
1529                 $table = $this->tableName( $table );
1530                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1531                 $res = $this->query( $sql, 'Database::textFieldSize' );
1532                 $row = $this->fetchObject( $res );
1533                 $this->freeResult( $res );
1534
1535                 if ( preg_match( "/\((.*)\)/", $row->Type, $m ) ) {
1536                         $size = $m[1];
1537                 } else {
1538                         $size = -1;
1539                 }
1540                 return $size;
1541         }
1542
1543         /**
1544          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1545          */
1546         function lowPriorityOption() {
1547                 return 'LOW_PRIORITY';
1548         }
1549
1550         /**
1551          * DELETE query wrapper
1552          *
1553          * Use $conds == "*" to delete all rows
1554          */
1555         function delete( $table, $conds, $fname = 'Database::delete' ) {
1556                 if ( !$conds ) {
1557                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1558                 }
1559                 $table = $this->tableName( $table );
1560                 $sql = "DELETE FROM $table";
1561                 if ( $conds != '*' ) {
1562                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1563                 }
1564                 return $this->query( $sql, $fname );
1565         }
1566
1567         /**
1568          * INSERT SELECT wrapper
1569          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1570          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1571          * $conds may be "*" to copy the whole table
1572          * srcTable may be an array of tables.
1573          */
1574         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1575                 $insertOptions = array(), $selectOptions = array() )
1576         {
1577                 $destTable = $this->tableName( $destTable );
1578                 if ( is_array( $insertOptions ) ) {
1579                         $insertOptions = implode( ' ', $insertOptions );
1580                 }
1581                 if( !is_array( $selectOptions ) ) {
1582                         $selectOptions = array( $selectOptions );
1583                 }
1584                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1585                 if( is_array( $srcTable ) ) {
1586                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1587                 } else {
1588                         $srcTable = $this->tableName( $srcTable );
1589                 }
1590                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1591                         " SELECT $startOpts " . implode( ',', $varMap ) .
1592                         " FROM $srcTable $useIndex ";
1593                 if ( $conds != '*' ) {
1594                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1595                 }
1596                 $sql .= " $tailOpts";
1597                 return $this->query( $sql, $fname );
1598         }
1599
1600         /**
1601          * Construct a LIMIT query with optional offset
1602          * This is used for query pages
1603          * $sql string SQL query we will append the limit too
1604          * $limit integer the SQL limit
1605          * $offset integer the SQL offset (default false)
1606          */
1607         function limitResult($sql, $limit, $offset=false) {
1608                 if( !is_numeric($limit) ) {
1609                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1610                 }
1611                 return " $sql LIMIT "
1612                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1613                                 . "{$limit} ";
1614         }
1615         function limitResultForUpdate($sql, $num) {
1616                 return $this->limitResult($sql, $num, 0);
1617         }
1618
1619         /**
1620          * Returns an SQL expression for a simple conditional.
1621          * Uses IF on MySQL.
1622          *
1623          * @param string $cond SQL expression which will result in a boolean value
1624          * @param string $trueVal SQL expression to return if true
1625          * @param string $falseVal SQL expression to return if false
1626          * @return string SQL fragment
1627          */
1628         function conditional( $cond, $trueVal, $falseVal ) {
1629                 return " IF($cond, $trueVal, $falseVal) ";
1630         }
1631
1632         /**
1633          * Determines if the last failure was due to a deadlock
1634          */
1635         function wasDeadlock() {
1636                 return $this->lastErrno() == 1213;
1637         }
1638
1639         /**
1640          * Perform a deadlock-prone transaction.
1641          *
1642          * This function invokes a callback function to perform a set of write
1643          * queries. If a deadlock occurs during the processing, the transaction
1644          * will be rolled back and the callback function will be called again.
1645          *
1646          * Usage:
1647          *   $dbw->deadlockLoop( callback, ... );
1648          *
1649          * Extra arguments are passed through to the specified callback function.
1650          *
1651          * Returns whatever the callback function returned on its successful,
1652          * iteration, or false on error, for example if the retry limit was
1653          * reached.
1654          */
1655         function deadlockLoop() {
1656                 $myFname = 'Database::deadlockLoop';
1657
1658                 $this->begin();
1659                 $args = func_get_args();
1660                 $function = array_shift( $args );
1661                 $oldIgnore = $this->ignoreErrors( true );
1662                 $tries = DEADLOCK_TRIES;
1663                 if ( is_array( $function ) ) {
1664                         $fname = $function[0];
1665                 } else {
1666                         $fname = $function;
1667                 }
1668                 do {
1669                         $retVal = call_user_func_array( $function, $args );
1670                         $error = $this->lastError();
1671                         $errno = $this->lastErrno();
1672                         $sql = $this->lastQuery();
1673
1674                         if ( $errno ) {
1675                                 if ( $this->wasDeadlock() ) {
1676                                         # Retry
1677                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1678                                 } else {
1679                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1680                                 }
1681                         }
1682                 } while( $this->wasDeadlock() && --$tries > 0 );
1683                 $this->ignoreErrors( $oldIgnore );
1684                 if ( $tries <= 0 ) {
1685                         $this->query( 'ROLLBACK', $myFname );
1686                         $this->reportQueryError( $error, $errno, $sql, $fname );
1687                         return false;
1688                 } else {
1689                         $this->query( 'COMMIT', $myFname );
1690                         return $retVal;
1691                 }
1692         }
1693
1694         /**
1695          * Do a SELECT MASTER_POS_WAIT()
1696          *
1697          * @param string $file the binlog file
1698          * @param string $pos the binlog position
1699          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1700          */
1701         function masterPosWait( $file, $pos, $timeout ) {
1702                 $fname = 'Database::masterPosWait';
1703                 wfProfileIn( $fname );
1704
1705
1706                 # Commit any open transactions
1707                 $this->immediateCommit();
1708
1709                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1710                 $encFile = $this->strencode( $file );
1711                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1712                 $res = $this->doQuery( $sql );
1713                 if ( $res && $row = $this->fetchRow( $res ) ) {
1714                         $this->freeResult( $res );
1715                         wfProfileOut( $fname );
1716                         return $row[0];
1717                 } else {
1718                         wfProfileOut( $fname );
1719                         return false;
1720                 }
1721         }
1722
1723         /**
1724          * Get the position of the master from SHOW SLAVE STATUS
1725          */
1726         function getSlavePos() {
1727                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1728                 $row = $this->fetchObject( $res );
1729                 if ( $row ) {
1730                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1731                 } else {
1732                         return array( false, false );
1733                 }
1734         }
1735
1736         /**
1737          * Get the position of the master from SHOW MASTER STATUS
1738          */
1739         function getMasterPos() {
1740                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1741                 $row = $this->fetchObject( $res );
1742                 if ( $row ) {
1743                         return array( $row->File, $row->Position );
1744                 } else {
1745                         return array( false, false );
1746                 }
1747         }
1748
1749         /**
1750          * Begin a transaction, committing any previously open transaction
1751          */
1752         function begin( $fname = 'Database::begin' ) {
1753                 $this->query( 'BEGIN', $fname );
1754                 $this->mTrxLevel = 1;
1755         }
1756
1757         /**
1758          * End a transaction
1759          */
1760         function commit( $fname = 'Database::commit' ) {
1761                 $this->query( 'COMMIT', $fname );
1762                 $this->mTrxLevel = 0;
1763         }
1764
1765         /**
1766          * Rollback a transaction
1767          */
1768         function rollback( $fname = 'Database::rollback' ) {
1769                 $this->query( 'ROLLBACK', $fname );
1770                 $this->mTrxLevel = 0;
1771         }
1772
1773         /**
1774          * Begin a transaction, committing any previously open transaction
1775          * @deprecated use begin()
1776          */
1777         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1778                 $this->begin();
1779         }
1780
1781         /**
1782          * Commit transaction, if one is open
1783          * @deprecated use commit()
1784          */
1785         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1786                 $this->commit();
1787         }
1788
1789         /**
1790          * Return MW-style timestamp used for MySQL schema
1791          */
1792         function timestamp( $ts=0 ) {
1793                 return wfTimestamp(TS_MW,$ts);
1794         }
1795
1796         /**
1797          * Local database timestamp format or null
1798          */
1799         function timestampOrNull( $ts = null ) {
1800                 if( is_null( $ts ) ) {
1801                         return null;
1802                 } else {
1803                         return $this->timestamp( $ts );
1804                 }
1805         }
1806
1807         /**
1808          * @todo document
1809          */
1810         function resultObject( $result ) {
1811                 if( empty( $result ) ) {
1812                         return NULL;
1813                 } else {
1814                         return new ResultWrapper( $this, $result );
1815                 }
1816         }
1817
1818         /**
1819          * Return aggregated value alias
1820          */
1821         function aggregateValue ($valuedata,$valuename='value') {
1822                 return $valuename;
1823         }
1824
1825         /**
1826          * @return string wikitext of a link to the server software's web site
1827          */
1828         function getSoftwareLink() {
1829                 return "[http://www.mysql.com/ MySQL]";
1830         }
1831
1832         /**
1833          * @return string Version information from the database
1834          */
1835         function getServerVersion() {
1836                 return mysql_get_server_info();
1837         }
1838
1839         /**
1840          * Ping the server and try to reconnect if it there is no connection
1841          */
1842         function ping() {
1843                 if( function_exists( 'mysql_ping' ) ) {
1844                         return mysql_ping( $this->mConn );
1845                 } else {
1846                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1847                         return true;
1848                 }
1849         }
1850
1851         /**
1852          * Get slave lag.
1853          * At the moment, this will only work if the DB user has the PROCESS privilege
1854          */
1855         function getLag() {
1856                 $res = $this->query( 'SHOW PROCESSLIST' );
1857                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1858                 # dubious, but unfortunately there's no easy rigorous way
1859                 $slaveThreads = 0;
1860                 while ( $row = $this->fetchObject( $res ) ) {
1861                         /* This should work for most situations - when default db
1862                          * for thread is not specified, it had no events executed,
1863                          * and therefore it doesn't know yet how lagged it is.
1864                          *
1865                          * Relay log I/O thread does not select databases.
1866                          */
1867                         if ( $row->User == 'system user' &&
1868                                 $row->State != 'Waiting for master to send event' &&
1869                                 $row->State != 'Connecting to master' &&
1870                                 $row->State != 'Queueing master event to the relay log' &&
1871                                 $row->State != 'Waiting for master update' &&
1872                                 $row->State != 'Requesting binlog dump'
1873                                 ) {
1874                                 # This is it, return the time (except -ve)
1875                                 if ( $row->Time > 0x7fffffff ) {
1876                                         return false;
1877                                 } else {
1878                                         return $row->Time;
1879                                 }
1880                         }
1881                 }
1882                 return false;
1883         }
1884
1885         /**
1886          * Get status information from SHOW STATUS in an associative array
1887          */
1888         function getStatus($which="%") {
1889                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1890                 $status = array();
1891                 while ( $row = $this->fetchObject( $res ) ) {
1892                         $status[$row->Variable_name] = $row->Value;
1893                 }
1894                 return $status;
1895         }
1896
1897         /**
1898          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1899          */
1900         function maxListLen() {
1901                 return 0;
1902         }
1903
1904         function encodeBlob($b) {
1905                 return $b;
1906         }
1907
1908         function decodeBlob($b) {
1909                 return $b;
1910         }
1911
1912         /**
1913          * Read and execute SQL commands from a file.
1914          * Returns true on success, error string on failure
1915          */
1916         function sourceFile( $filename ) {
1917                 $fp = fopen( $filename, 'r' );
1918                 if ( false === $fp ) {
1919                         return "Could not open \"{$filename}\".\n";
1920                 }
1921
1922                 $cmd = "";
1923                 $done = false;
1924                 $dollarquote = false;
1925
1926                 while ( ! feof( $fp ) ) {
1927                         $line = trim( fgets( $fp, 1024 ) );
1928                         $sl = strlen( $line ) - 1;
1929
1930                         if ( $sl < 0 ) { continue; }
1931                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
1932
1933                         ## Allow dollar quoting for function declarations
1934                         if (substr($line,0,4) == '$mw$') {
1935                                 if ($dollarquote) {
1936                                         $dollarquote = false;
1937                                         $done = true;
1938                                 }
1939                                 else {
1940                                         $dollarquote = true;
1941                                 }
1942                         }
1943                         else if (!$dollarquote) {
1944                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
1945                                         $done = true;
1946                                         $line = substr( $line, 0, $sl );
1947                                 }
1948                         }
1949
1950                         if ( '' != $cmd ) { $cmd .= ' '; }
1951                         $cmd .= "$line\n";
1952
1953                         if ( $done ) {
1954                                 $cmd = str_replace(';;', ";", $cmd);
1955                                 $cmd = $this->replaceVars( $cmd );
1956                                 $res = $this->query( $cmd, 'dbsource', true );
1957
1958                                 if ( false === $res ) {
1959                                         $err = $this->lastError();
1960                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
1961                                 }
1962
1963                                 $cmd = '';
1964                                 $done = false;
1965                         }
1966                 }
1967                 fclose( $fp );
1968                 return true;
1969         }
1970
1971         /**
1972          * Replace variables in sourced SQL
1973          */
1974         protected function replaceVars( $ins ) {
1975                 $varnames = array(
1976                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
1977                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
1978                         'wgDBadminuser', 'wgDBadminpassword',
1979                 );
1980
1981                 // Ordinary variables
1982                 foreach ( $varnames as $var ) {
1983                         if( isset( $GLOBALS[$var] ) ) {
1984                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
1985                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
1986                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
1987                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
1988                         }
1989                 }
1990
1991                 // Table prefixes
1992                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
1993                         array( &$this, 'tableNameCallback' ), $ins );
1994                 return $ins;
1995         }
1996
1997         /**
1998          * Table name callback
1999          * @private
2000          */
2001         protected function tableNameCallback( $matches ) {
2002                 return $this->tableName( $matches[1] );
2003         }
2004
2005 }
2006
2007 /**
2008  * Database abstraction object for mySQL
2009  * Inherit all methods and properties of Database::Database()
2010  *
2011  * @package MediaWiki
2012  * @see Database
2013  */
2014 class DatabaseMysql extends Database {
2015         # Inherit all
2016 }
2017
2018
2019 /**
2020  * Result wrapper for grabbing data queried by someone else
2021  *
2022  * @package MediaWiki
2023  */
2024 class ResultWrapper {
2025         var $db, $result;
2026
2027         /**
2028          * @todo document
2029          */
2030         function ResultWrapper( &$database, $result ) {
2031                 $this->db =& $database;
2032                 $this->result =& $result;
2033         }
2034
2035         /**
2036          * @todo document
2037          */
2038         function numRows() {
2039                 return $this->db->numRows( $this->result );
2040         }
2041
2042         /**
2043          * @todo document
2044          */
2045         function fetchObject() {
2046                 return $this->db->fetchObject( $this->result );
2047         }
2048
2049         /**
2050          * @todo document
2051          */
2052         function fetchRow() {
2053                 return $this->db->fetchRow( $this->result );
2054         }
2055
2056         /**
2057          * @todo document
2058          */
2059         function free() {
2060                 $this->db->freeResult( $this->result );
2061                 unset( $this->result );
2062                 unset( $this->db );
2063         }
2064
2065         function seek( $row ) {
2066                 $this->db->dataSeek( $this->result, $row );
2067         }
2068
2069 }
2070
2071 ?>