includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  * @package MediaWiki
   6  */
   7
   8 /** See Database::makeList() */
   9 define( 'LIST_COMMA', 0 );
  10 define( 'LIST_AND', 1 );
  11 define( 'LIST_SET', 2 );
  12 define( 'LIST_NAMES', 3);
  13 define( 'LIST_OR', 4);
  14
  15 /** Number of times to re-try an operation in case of deadlock */
  16 define( 'DEADLOCK_TRIES', 4 );
  17 /** Minimum time to wait before retry, in microseconds */
  18 define( 'DEADLOCK_DELAY_MIN', 500000 );
  19 /** Maximum time to wait before retry */
  20 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  21
  22 /******************************************************************************
  23  * Utility classes
  24  *****************************************************************************/
  25
  26 class DBObject {
  27         public $mData;
  28
  29         function DBObject($data) {
  30                 $this->mData = $data;
  31         }
  32
  33         function isLOB() {
  34                 return false;
  35         }
  36
  37         function data() {
  38                 return $this->mData;
  39         }
  40 };
  41
  42 /******************************************************************************
  43  * Error classes
  44  *****************************************************************************/
  45
  46 /**
  47  * Database error base class
  48  */
  49 class DBError extends MWException {
  50         public $db;
  51
  52         /**
  53          * Construct a database error
  54          * @param Database $db The database object which threw the error
  55          * @param string $error A simple error message to be used for debugging
  56          */
  57         function __construct( Database &$db, $error ) {
  58                 $this->db =& $db;
  59                 parent::__construct( $error );
  60         }
  61 }
  62
  63 class DBConnectionError extends DBError {
  64         public $error;
  65
  66         function __construct( Database &$db, $error = 'unknown error' ) {
  67                 $msg = 'DB connection error';
  68                 if ( trim( $error ) != '' ) {
  69                         $msg .= ": $error";
  70                 }
  71                 $this->error = $error;
  72                 parent::__construct( $db, $msg );
  73         }
  74
  75         function useOutputPage() {
  76                 // Not likely to work
  77                 return false;
  78         }
  79
  80         function useMessageCache() {
  81                 // Not likely to work
  82                 return false;
  83         }
  84
  85         function getText() {
  86                 return $this->getMessage() . "\n";
  87         }
  88
  89         function getLogMessage() {
  90                 # Don't send to the exception log
  91                 return false;
  92         }
  93
  94         function getPageTitle() {
  95                 global $wgSitename;
  96                 return "$wgSitename has a problem";
  97         }
  98
  99         function getHTML() {
 100                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgOutputEncoding;
 101                 global $wgSitename, $wgServer, $wgMessageCache, $wgLogo;
 102
 103                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
 104                 # Hard coding strings instead.
 105
 106                 $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>";
 107                 $mainpage = 'Main Page';
 108                 $searchdisabled = <<<EOT
 109 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
 110 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
 111 EOT;
 112
 113                 $googlesearch = "
 114 <!-- SiteSearch Google -->
 115 <FORM method=GET action=\"http://www.google.com/search\">
 116 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
 117 <A HREF=\"http://www.google.com/\">
 118 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
 119 border=\"0\" ALT=\"Google\"></A>
 120 </td>
 121 <td>
 122 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
 123 <INPUT type=submit name=btnG VALUE=\"Google Search\">
 124 <font size=-1>
 125 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
 126 <input type='hidden' name='ie' value='$2'>
 127 <input type='hidden' name='oe' value='$2'>
 128 </font>
 129 </td></tr></TABLE>
 130 </FORM>
 131 <!-- SiteSearch Google -->";
 132                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
 133
 134                 # No database access
 135                 if ( is_object( $wgMessageCache ) ) {
 136                         $wgMessageCache->disable();
 137                 }
 138
 139                 if ( trim( $this->error ) == '' ) {
 140                         $this->error = $this->db->getProperty('mServer');
 141                 }
 142
 143                 $text = str_replace( '$1', $this->error, $noconnect );
 144                 $text .= wfGetSiteNotice();
 145
 146                 if($wgUseFileCache) {
 147                         if($wgTitle) {
 148                                 $t =& $wgTitle;
 149                         } else {
 150                                 if($title) {
 151                                         $t = Title::newFromURL( $title );
 152                                 } elseif (@/**/$_REQUEST['search']) {
 153                                         $search = $_REQUEST['search'];
 154                                         return $searchdisabled .
 155                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
 156                                           $wgInputEncoding ), $googlesearch );
 157                                 } else {
 158                                         $t = Title::newFromText( $mainpage );
 159                                 }
 160                         }
 161
 162                         $cache = new CacheManager( $t );
 163                         if( $cache->isFileCached() ) {
 164                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
 165                                         $cachederror . "</b></p>\n";
 166
 167                                 $tag = '<div id="article">';
 168                                 $text = str_replace(
 169                                         $tag,
 170                                         $tag . $msg,
 171                                         $cache->fetchPageText() );
 172                         }
 173                 }
 174
 175                 return $text;
 176         }
 177 }
 178
 179 class DBQueryError extends DBError {
 180         public $error, $errno, $sql, $fname;
 181
 182         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
 183                 $message = "A database error has occurred\n" .
 184                   "Query: $sql\n" .
 185                   "Function: $fname\n" .
 186                   "Error: $errno $error\n";
 187
 188                 parent::__construct( $db, $message );
 189                 $this->error = $error;
 190                 $this->errno = $errno;
 191                 $this->sql = $sql;
 192                 $this->fname = $fname;
 193         }
 194
 195         function getText() {
 196                 if ( $this->useMessageCache() ) {
 197                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
 198                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
 199                 } else {
 200                         return $this->getMessage();
 201                 }
 202         }
 203
 204         function getSQL() {
 205                 global $wgShowSQLErrors;
 206                 if( !$wgShowSQLErrors ) {
 207                         return $this->msg( 'sqlhidden', 'SQL hidden' );
 208                 } else {
 209                         return $this->sql;
 210                 }
 211         }
 212
 213         function getLogMessage() {
 214                 # Don't send to the exception log
 215                 return false;
 216         }
 217
 218         function getPageTitle() {
 219                 return $this->msg( 'databaseerror', 'Database error' );
 220         }
 221
 222         function getHTML() {
 223                 if ( $this->useMessageCache() ) {
 224                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
 225                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
 226                 } else {
 227                         return nl2br( htmlspecialchars( $this->getMessage() ) );
 228                 }
 229         }
 230 }
 231
 232 class DBUnexpectedError extends DBError {}
 233
 234 /******************************************************************************/
 235
 236 /**
 237  * Database abstraction object
 238  * @package MediaWiki
 239  */
 240 class Database {
 241
 242 #------------------------------------------------------------------------------
 243 # Variables
 244 #------------------------------------------------------------------------------
 245
 246         protected $mLastQuery = '';
 247
 248         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 249         protected $mOut, $mOpened = false;
 250
 251         protected $mFailFunction;
 252         protected $mTablePrefix;
 253         protected $mFlags;
 254         protected $mTrxLevel = 0;
 255         protected $mErrorCount = 0;
 256         protected $mLBInfo = array();
 257         protected $mCascadingDeletes = false;
 258         protected $mCleanupTriggers = false;
 259         protected $mStrictIPs = false;
 260
 261 #------------------------------------------------------------------------------
 262 # Accessors
 263 #------------------------------------------------------------------------------
 264         # These optionally set a variable and return the previous state
 265
 266         /**
 267          * Fail function, takes a Database as a parameter
 268          * Set to false for default, 1 for ignore errors
 269          */
 270         function failFunction( $function = NULL ) {
 271                 return wfSetVar( $this->mFailFunction, $function );
 272         }
 273
 274         /**
 275          * Output page, used for reporting errors
 276          * FALSE means discard output
 277          */
 278         function setOutputPage( $out ) {
 279                 $this->mOut = $out;
 280         }
 281
 282         /**
 283          * Boolean, controls output of large amounts of debug information
 284          */
 285         function debug( $debug = NULL ) {
 286                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
 287         }
 288
 289         /**
 290          * Turns buffering of SQL result sets on (true) or off (false).
 291          * Default is "on" and it should not be changed without good reasons.
 292          */
 293         function bufferResults( $buffer = NULL ) {
 294                 if ( is_null( $buffer ) ) {
 295                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 296                 } else {
 297                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 298                 }
 299         }
 300
 301         /**
 302          * Turns on (false) or off (true) the automatic generation and sending
 303          * of a "we're sorry, but there has been a database error" page on
 304          * database errors. Default is on (false). When turned off, the
 305          * code should use wfLastErrno() and wfLastError() to handle the
 306          * situation as appropriate.
 307          */
 308         function ignoreErrors( $ignoreErrors = NULL ) {
 309                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 310         }
 311
 312         /**
 313          * The current depth of nested transactions
 314          * @param $level Integer: , default NULL.
 315          */
 316         function trxLevel( $level = NULL ) {
 317                 return wfSetVar( $this->mTrxLevel, $level );
 318         }
 319
 320         /**
 321          * Number of errors logged, only useful when errors are ignored
 322          */
 323         function errorCount( $count = NULL ) {
 324                 return wfSetVar( $this->mErrorCount, $count );
 325         }
 326
 327         /**
 328          * Properties passed down from the server info array of the load balancer
 329          */
 330         function getLBInfo( $name = NULL ) {
 331                 if ( is_null( $name ) ) {
 332                         return $this->mLBInfo;
 333                 } else {
 334                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 335                                 return $this->mLBInfo[$name];
 336                         } else {
 337                                 return NULL;
 338                         }
 339                 }
 340         }
 341
 342         function setLBInfo( $name, $value = NULL ) {
 343                 if ( is_null( $value ) ) {
 344                         $this->mLBInfo = $name;
 345                 } else {
 346                         $this->mLBInfo[$name] = $value;
 347                 }
 348         }
 349
 350         /**
 351          * Returns true if this database supports (and uses) cascading deletes
 352          */
 353         function cascadingDeletes() {
 354                 return $this->mCascadingDeletes;
 355         }
 356
 357         /**
 358          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 359          */
 360         function cleanupTriggers() {
 361                 return $this->mCleanupTriggers;
 362         }
 363
 364         /**
 365          * Returns true if this database is strict about what can be put into an IP field.
 366          * Specifically, it uses a NULL value instead of an empty string.
 367          */
 368         function strictIPs() {
 369                 return $this->mStrictIPs;
 370         }
 371
 372         /**#@+
 373          * Get function
 374          */
 375         function lastQuery() { return $this->mLastQuery; }
 376         function isOpen() { return $this->mOpened; }
 377         /**#@-*/
 378
 379         function setFlag( $flag ) {
 380                 $this->mFlags |= $flag;
 381         }
 382
 383         function clearFlag( $flag ) {
 384                 $this->mFlags &= ~$flag;
 385         }
 386
 387         function getFlag( $flag ) {
 388                 return !!($this->mFlags & $flag);
 389         }
 390
 391         /**
 392          * General read-only accessor
 393          */
 394         function getProperty( $name ) {
 395                 return $this->$name;
 396         }
 397
 398 #------------------------------------------------------------------------------
 399 # Other functions
 400 #------------------------------------------------------------------------------
 401
 402         /**@{{
 403          * @param string $server database server host
 404          * @param string $user database user name
 405          * @param string $password database user password
 406          * @param string $dbname database name
 407          */
 408
 409         /**
 410          * @param failFunction
 411          * @param $flags
 412          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 413          */
 414         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 415                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 416
 417                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 418                 # Can't get a reference if it hasn't been set yet
 419                 if ( !isset( $wgOut ) ) {
 420                         $wgOut = NULL;
 421                 }
 422                 $this->mOut =& $wgOut;
 423
 424                 $this->mFailFunction = $failFunction;
 425                 $this->mFlags = $flags;
 426
 427                 if ( $this->mFlags & DBO_DEFAULT ) {
 428                         if ( $wgCommandLineMode ) {
 429                                 $this->mFlags &= ~DBO_TRX;
 430                         } else {
 431                                 $this->mFlags |= DBO_TRX;
 432                         }
 433                 }
 434
 435                 /*
 436                 // Faster read-only access
 437                 if ( wfReadOnly() ) {
 438                         $this->mFlags |= DBO_PERSISTENT;
 439                         $this->mFlags &= ~DBO_TRX;
 440                 }*/
 441
 442                 /** Get the default table prefix*/
 443                 if ( $tablePrefix == 'get from global' ) {
 444                         $this->mTablePrefix = $wgDBprefix;
 445                 } else {
 446                         $this->mTablePrefix = $tablePrefix;
 447                 }
 448
 449                 if ( $server ) {
 450                         $this->open( $server, $user, $password, $dbName );
 451                 }
 452         }
 453
 454         /**
 455          * @static
 456          * @param failFunction
 457          * @param $flags
 458          */
 459         static function newFromParams( $server, $user, $password, $dbName,
 460                 $failFunction = false, $flags = 0 )
 461         {
 462                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 463         }
 464
 465         /**
 466          * Usually aborts on failure
 467          * If the failFunction is set to a non-zero integer, returns success
 468          */
 469         function open( $server, $user, $password, $dbName ) {
 470                 global $wguname;
 471                 wfProfileIn( __METHOD__ );
 472
 473                 # Test for missing mysql.so
 474                 # First try to load it
 475                 if (!@extension_loaded('mysql')) {
 476                         @dl('mysql.so');
 477                 }
 478
 479                 # Fail now
 480                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 481                 if ( !function_exists( 'mysql_connect' ) ) {
 482                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 483                 }
 484
 485                 $this->close();
 486                 $this->mServer = $server;
 487                 $this->mUser = $user;
 488                 $this->mPassword = $password;
 489                 $this->mDBname = $dbName;
 490
 491                 $success = false;
 492
 493                 wfProfileIn("dbconnect-$server");
 494
 495                 # LIVE PATCH by Tim, ask Domas for why: retry loop
 496                 $this->mConn = false;
 497                 $max = 3;
 498                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 499                         if ( $i > 1 ) {
 500                                 usleep( 1000 );
 501                         }
 502                         if ( $this->mFlags & DBO_PERSISTENT ) {
 503                                 @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 504                         } else {
 505                                 # Create a new connection...
 506                                 @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 507                         }
 508                         if ($this->mConn === false) {
 509                                 $iplus = $i + 1;
 510                                 wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 511                         }
 512                 }
 513
 514                 wfProfileOut("dbconnect-$server");
 515
 516                 if ( $dbName != '' ) {
 517                         if ( $this->mConn !== false ) {
 518                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 519                                 if ( !$success ) {
 520                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 521                                                 "from client host {$wguname['nodename']}\n";
 522                                         wfLogDBError(" Error selecting database $dbname on server {$this->mServer} \n");
 523                                         wfDebug( $error );
 524                                 }
 525                         } else {
 526                                 wfDebug( "DB connection error\n" );
 527                                 wfDebug( "Server: $server, User: $user, Password: " .
 528                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 529                                 $success = false;
 530                         }
 531                 } else {
 532                         # Delay USE query
 533                         $success = (bool)$this->mConn;
 534                 }
 535
 536                 if ( $success ) {
 537                         global $wgDBmysql5;
 538                         if( $wgDBmysql5 ) {
 539                                 // Tell the server we're communicating with it in UTF-8.
 540                                 // This may engage various charset conversions.
 541                                 $this->query( 'SET NAMES utf8' );
 542                         }
 543                 } else {
 544                         $this->reportConnectionError();
 545                 }
 546
 547                 $this->mOpened = $success;
 548                 wfProfileOut( __METHOD__ );
 549                 return $success;
 550         }
 551         /**@}}*/
 552
 553         /**
 554          * Closes a database connection.
 555          * if it is open : commits any open transactions
 556          *
 557          * @return bool operation success. true if already closed.
 558          */
 559         function close()
 560         {
 561                 $this->mOpened = false;
 562                 if ( $this->mConn ) {
 563                         if ( $this->trxLevel() ) {
 564                                 $this->immediateCommit();
 565                         }
 566                         return mysql_close( $this->mConn );
 567                 } else {
 568                         return true;
 569                 }
 570         }
 571
 572         /**
 573          * @param string $error fallback error message, used if none is given by MySQL
 574          */
 575         function reportConnectionError( $error = 'Unknown error' ) {
 576                 $myError = $this->lastError();
 577                 if ( $myError ) {
 578                         $error = $myError;
 579                 }
 580
 581                 if ( $this->mFailFunction ) {
 582                         # Legacy error handling method
 583                         if ( !is_int( $this->mFailFunction ) ) {
 584                                 $ff = $this->mFailFunction;
 585                                 $ff( $this, $error );
 586                         }
 587                 } else {
 588                         # New method
 589                         wfLogDBError( "Connection error: $error\n" );
 590                         throw new DBConnectionError( $this, $error );
 591                 }
 592         }
 593
 594         /**
 595          * Usually aborts on failure
 596          * If errors are explicitly ignored, returns success
 597          */
 598         function query( $sql, $fname = '', $tempIgnore = false ) {
 599                 global $wgProfiling;
 600
 601                 if ( $wgProfiling ) {
 602                         # generalizeSQL will probably cut down the query to reasonable
 603                         # logging size most of the time. The substr is really just a sanity check.
 604
 605                         # Who's been wasting my precious column space? -- TS
 606                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 607
 608                         if ( is_null( $this->getLBInfo( 'master' ) ) ) {
 609                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 610                                 $totalProf = 'Database::query';
 611                         } else {
 612                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 613                                 $totalProf = 'Database::query-master';
 614                         }
 615                         wfProfileIn( $totalProf );
 616                         wfProfileIn( $queryProf );
 617                 }
 618
 619                 $this->mLastQuery = $sql;
 620
 621                 # Add a comment for easy SHOW PROCESSLIST interpretation
 622                 if ( $fname ) {
 623                         $commentedSql = preg_replace("/\s/", " /* $fname */ ", $sql, 1);
 624                 } else {
 625                         $commentedSql = $sql;
 626                 }
 627
 628                 # If DBO_TRX is set, start a transaction
 629                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 630                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK'
 631                 ) {
 632                         $this->begin();
 633                 }
 634
 635                 if ( $this->debug() ) {
 636                         $sqlx = substr( $commentedSql, 0, 500 );
 637                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 638                         wfDebug( "SQL: $sqlx\n" );
 639                 }
 640
 641                 # Do the query and handle errors
 642                 $ret = $this->doQuery( $commentedSql );
 643
 644                 # Try reconnecting if the connection was lost
 645                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 646                         # Transaction is gone, like it or not
 647                         $this->mTrxLevel = 0;
 648                         wfDebug( "Connection lost, reconnecting...\n" );
 649                         if ( $this->ping() ) {
 650                                 wfDebug( "Reconnected\n" );
 651                                 $ret = $this->doQuery( $commentedSql );
 652                         } else {
 653                                 wfDebug( "Failed\n" );
 654                         }
 655                 }
 656
 657                 if ( false === $ret ) {
 658                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 659                 }
 660
 661                 if ( $wgProfiling ) {
 662                         wfProfileOut( $queryProf );
 663                         wfProfileOut( $totalProf );
 664                 }
 665                 return $ret;
 666         }
 667
 668         /**
 669          * The DBMS-dependent part of query()
 670          * @param string $sql SQL query.
 671          */
 672         function doQuery( $sql ) {
 673                 if( $this->bufferResults() ) {
 674                         $ret = mysql_query( $sql, $this->mConn );
 675                 } else {
 676                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 677                 }
 678                 return $ret;
 679         }
 680
 681         /**
 682          * @param $error
 683          * @param $errno
 684          * @param $sql
 685          * @param string $fname
 686          * @param bool $tempIgnore
 687          */
 688         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 689                 global $wgCommandLineMode, $wgFullyInitialised, $wgColorErrors;
 690                 # Ignore errors during error handling to avoid infinite recursion
 691                 $ignore = $this->ignoreErrors( true );
 692                 ++$this->mErrorCount;
 693
 694                 if( $ignore || $tempIgnore ) {
 695                         wfDebug("SQL ERROR (ignored): $error\n");
 696                         $this->ignoreErrors( $ignore );
 697                 } else {
 698                         $sql1line = str_replace( "\n", "\\n", $sql );
 699                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 700                         wfDebug("SQL ERROR: " . $error . "\n");
 701                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 702                 }
 703         }
 704
 705
 706         /**
 707          * Intended to be compatible with the PEAR::DB wrapper functions.
 708          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 709          *
 710          * ? = scalar value, quoted as necessary
 711          * ! = raw SQL bit (a function for instance)
 712          * & = filename; reads the file and inserts as a blob
 713          *     (we don't use this though...)
 714          */
 715         function prepare( $sql, $func = 'Database::prepare' ) {
 716                 /* MySQL doesn't support prepared statements (yet), so just
 717                    pack up the query for reference. We'll manually replace
 718                    the bits later. */
 719                 return array( 'query' => $sql, 'func' => $func );
 720         }
 721
 722         function freePrepared( $prepared ) {
 723                 /* No-op for MySQL */
 724         }
 725
 726         /**
 727          * Execute a prepared query with the various arguments
 728          * @param string $prepared the prepared sql
 729          * @param mixed $args Either an array here, or put scalars as varargs
 730          */
 731         function execute( $prepared, $args = null ) {
 732                 if( !is_array( $args ) ) {
 733                         # Pull the var args
 734                         $args = func_get_args();
 735                         array_shift( $args );
 736                 }
 737                 $sql = $this->fillPrepared( $prepared['query'], $args );
 738                 return $this->query( $sql, $prepared['func'] );
 739         }
 740
 741         /**
 742          * Prepare & execute an SQL statement, quoting and inserting arguments
 743          * in the appropriate places.
 744          * @param string $query
 745          * @param string $args ...
 746          */
 747         function safeQuery( $query, $args = null ) {
 748                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 749                 if( !is_array( $args ) ) {
 750                         # Pull the var args
 751                         $args = func_get_args();
 752                         array_shift( $args );
 753                 }
 754                 $retval = $this->execute( $prepared, $args );
 755                 $this->freePrepared( $prepared );
 756                 return $retval;
 757         }
 758
 759         /**
 760          * For faking prepared SQL statements on DBs that don't support
 761          * it directly.
 762          * @param string $preparedSql - a 'preparable' SQL statement
 763          * @param array $args - array of arguments to fill it with
 764          * @return string executable SQL
 765          */
 766         function fillPrepared( $preparedQuery, $args ) {
 767                 reset( $args );
 768                 $this->preparedArgs =& $args;
 769                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 770                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 771         }
 772
 773         /**
 774          * preg_callback func for fillPrepared()
 775          * The arguments should be in $this->preparedArgs and must not be touched
 776          * while we're doing this.
 777          *
 778          * @param array $matches
 779          * @return string
 780          * @private
 781          */
 782         function fillPreparedArg( $matches ) {
 783                 switch( $matches[1] ) {
 784                         case '\\?': return '?';
 785                         case '\\!': return '!';
 786                         case '\\&': return '&';
 787                 }
 788                 list( $n, $arg ) = each( $this->preparedArgs );
 789                 switch( $matches[1] ) {
 790                         case '?': return $this->addQuotes( $arg );
 791                         case '!': return $arg;
 792                         case '&':
 793                                 # return $this->addQuotes( file_get_contents( $arg ) );
 794                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 795                         default:
 796                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 797                 }
 798         }
 799
 800         /**#@+
 801          * @param mixed $res A SQL result
 802          */
 803         /**
 804          * Free a result object
 805          */
 806         function freeResult( $res ) {
 807                 if ( !@/**/mysql_free_result( $res ) ) {
 808                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 809                 }
 810         }
 811
 812         /**
 813          * Fetch the next row from the given result object, in object form
 814          */
 815         function fetchObject( $res ) {
 816                 @/**/$row = mysql_fetch_object( $res );
 817                 if( $this->lastErrno() ) {
 818                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 819                 }
 820                 return $row;
 821         }
 822
 823         /**
 824          * Fetch the next row from the given result object
 825          * Returns an array
 826          */
 827         function fetchRow( $res ) {
 828                 @/**/$row = mysql_fetch_array( $res );
 829                 if ( $this->lastErrno() ) {
 830                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 831                 }
 832                 return $row;
 833         }
 834
 835         /**
 836          * Get the number of rows in a result object
 837          */
 838         function numRows( $res ) {
 839                 @/**/$n = mysql_num_rows( $res );
 840                 if( $this->lastErrno() ) {
 841                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 842                 }
 843                 return $n;
 844         }
 845
 846         /**
 847          * Get the number of fields in a result object
 848          * See documentation for mysql_num_fields()
 849          */
 850         function numFields( $res ) { return mysql_num_fields( $res ); }
 851
 852         /**
 853          * Get a field name in a result object
 854          * See documentation for mysql_field_name():
 855          * http://www.php.net/mysql_field_name
 856          */
 857         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 858
 859         /**
 860          * Get the inserted value of an auto-increment row
 861          *
 862          * The value inserted should be fetched from nextSequenceValue()
 863          *
 864          * Example:
 865          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 866          * $dbw->insert('page',array('page_id' => $id));
 867          * $id = $dbw->insertId();
 868          */
 869         function insertId() { return mysql_insert_id( $this->mConn ); }
 870
 871         /**
 872          * Change the position of the cursor in a result object
 873          * See mysql_data_seek()
 874          */
 875         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 876
 877         /**
 878          * Get the last error number
 879          * See mysql_errno()
 880          */
 881         function lastErrno() {
 882                 if ( $this->mConn ) {
 883                         return mysql_errno( $this->mConn );
 884                 } else {
 885                         return mysql_errno();
 886                 }
 887         }
 888
 889         /**
 890          * Get a description of the last error
 891          * See mysql_error() for more details
 892          */
 893         function lastError() {
 894                 if ( $this->mConn ) {
 895                         # Even if it's non-zero, it can still be invalid
 896                         wfSuppressWarnings();
 897                         $error = mysql_error( $this->mConn );
 898                         if ( !$error ) {
 899                                 $error = mysql_error();
 900                         }
 901                         wfRestoreWarnings();
 902                 } else {
 903                         $error = mysql_error();
 904                 }
 905                 if( $error ) {
 906                         $error .= ' (' . $this->mServer . ')';
 907                 }
 908                 return $error;
 909         }
 910         /**
 911          * Get the number of rows affected by the last write query
 912          * See mysql_affected_rows() for more details
 913          */
 914         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 915         /**#@-*/ // end of template : @param $result
 916
 917         /**
 918          * Simple UPDATE wrapper
 919          * Usually aborts on failure
 920          * If errors are explicitly ignored, returns success
 921          *
 922          * This function exists for historical reasons, Database::update() has a more standard
 923          * calling convention and feature set
 924          */
 925         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 926         {
 927                 $table = $this->tableName( $table );
 928                 $sql = "UPDATE $table SET $var = '" .
 929                   $this->strencode( $value ) . "' WHERE ($cond)";
 930                 return (bool)$this->query( $sql, $fname );
 931         }
 932
 933         /**
 934          * Simple SELECT wrapper, returns a single field, input must be encoded
 935          * Usually aborts on failure
 936          * If errors are explicitly ignored, returns FALSE on failure
 937          */
 938         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 939                 if ( !is_array( $options ) ) {
 940                         $options = array( $options );
 941                 }
 942                 $options['LIMIT'] = 1;
 943
 944                 $res = $this->select( $table, $var, $cond, $fname, $options );
 945                 if ( $res === false || !$this->numRows( $res ) ) {
 946                         return false;
 947                 }
 948                 $row = $this->fetchRow( $res );
 949                 if ( $row !== false ) {
 950                         $this->freeResult( $res );
 951                         return $row[0];
 952                 } else {
 953                         return false;
 954                 }
 955         }
 956
 957         /**
 958          * Returns an optional USE INDEX clause to go after the table, and a
 959          * string to go at the end of the query
 960          *
 961          * @private
 962          *
 963          * @param array $options an associative array of options to be turned into
 964          *              an SQL query, valid keys are listed in the function.
 965          * @return array
 966          */
 967         function makeSelectOptions( $options ) {
 968                 $tailOpts = '';
 969                 $startOpts = '';
 970
 971                 $noKeyOptions = array();
 972                 foreach ( $options as $key => $option ) {
 973                         if ( is_numeric( $key ) ) {
 974                                 $noKeyOptions[$option] = true;
 975                         }
 976                 }
 977
 978                 if ( isset( $options['GROUP BY'] ) ) $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 979                 if ( isset( $options['ORDER BY'] ) ) $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 980
 981                 if (isset($options['LIMIT'])) {
 982                         $tailOpts .= $this->limitResult('', $options['LIMIT'],
 983                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 984                 }
 985
 986                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $tailOpts .= ' FOR UPDATE';
 987                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $tailOpts .= ' LOCK IN SHARE MODE';
 988                 if ( isset( $noKeyOptions['DISTINCT'] ) && isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 989
 990                 # Various MySQL extensions
 991                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 992                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 993                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 994                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 995                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 996                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 997                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 998
 999                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
1000                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1001                 } else {
1002                         $useIndex = '';
1003                 }
1004
1005                 return array( $startOpts, $useIndex, $tailOpts );
1006         }
1007
1008         /**
1009          * SELECT wrapper
1010          */
1011         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
1012         {
1013                 if( is_array( $vars ) ) {
1014                         $vars = implode( ',', $vars );
1015                 }
1016                 if( !is_array( $options ) ) {
1017                         $options = array( $options );
1018                 }
1019                 if( is_array( $table ) ) {
1020                         if ( @is_array( $options['USE INDEX'] ) )
1021                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
1022                         else
1023                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1024                 } elseif ($table!='') {
1025                         $from = ' FROM ' . $this->tableName( $table );
1026                 } else {
1027                         $from = '';
1028                 }
1029
1030                 list( $startOpts, $useIndex, $tailOpts ) = $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 $tailOpts";
1037                 } else {
1038                         $sql = "SELECT $startOpts $vars $from $useIndex $tailOpts";
1039                 }
1040
1041                 return $this->query( $sql, $fname );
1042         }
1043
1044         /**
1045          * Single row SELECT wrapper
1046          * Aborts or returns FALSE on error
1047          *
1048          * $vars: the selected variables
1049          * $conds: a condition map, terms are ANDed together.
1050          *   Items with numeric keys are taken to be literal conditions
1051          * Takes an array of selected variables, and a condition map, which is ANDed
1052          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1053          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1054          * $obj- >page_id is the ID of the Astronomy article
1055          *
1056          * @todo migrate documentation to phpdocumentor format
1057          */
1058         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
1059                 $options['LIMIT'] = 1;
1060                 $res = $this->select( $table, $vars, $conds, $fname, $options );
1061                 if ( $res === false )
1062                         return false;
1063                 if ( !$this->numRows($res) ) {
1064                         $this->freeResult($res);
1065                         return false;
1066                 }
1067                 $obj = $this->fetchObject( $res );
1068                 $this->freeResult( $res );
1069                 return $obj;
1070
1071         }
1072
1073         /**
1074          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1075          * It's only slightly flawed. Don't use for anything important.
1076          *
1077          * @param string $sql A SQL Query
1078          * @static
1079          */
1080         static function generalizeSQL( $sql ) {
1081                 # This does the same as the regexp below would do, but in such a way
1082                 # as to avoid crashing php on some large strings.
1083                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1084
1085                 $sql = str_replace ( "\\\\", '', $sql);
1086                 $sql = str_replace ( "\\'", '', $sql);
1087                 $sql = str_replace ( "\\\"", '', $sql);
1088                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1089                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1090
1091                 # All newlines, tabs, etc replaced by single space
1092                 $sql = preg_replace ( "/\s+/", ' ', $sql);
1093
1094                 # All numbers => N
1095                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1096
1097                 return $sql;
1098         }
1099
1100         /**
1101          * Determines whether a field exists in a table
1102          * Usually aborts on failure
1103          * If errors are explicitly ignored, returns NULL on failure
1104          */
1105         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1106                 $table = $this->tableName( $table );
1107                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1108                 if ( !$res ) {
1109                         return NULL;
1110                 }
1111
1112                 $found = false;
1113
1114                 while ( $row = $this->fetchObject( $res ) ) {
1115                         if ( $row->Field == $field ) {
1116                                 $found = true;
1117                                 break;
1118                         }
1119                 }
1120                 return $found;
1121         }
1122
1123         /**
1124          * Determines whether an index exists
1125          * Usually aborts on failure
1126          * If errors are explicitly ignored, returns NULL on failure
1127          */
1128         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1129                 $info = $this->indexInfo( $table, $index, $fname );
1130                 if ( is_null( $info ) ) {
1131                         return NULL;
1132                 } else {
1133                         return $info !== false;
1134                 }
1135         }
1136
1137
1138         /**
1139          * Get information about an index into an object
1140          * Returns false if the index does not exist
1141          */
1142         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1143                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1144                 # SHOW INDEX should work for 3.x and up:
1145                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1146                 $table = $this->tableName( $table );
1147                 $sql = 'SHOW INDEX FROM '.$table;
1148                 $res = $this->query( $sql, $fname );
1149                 if ( !$res ) {
1150                         return NULL;
1151                 }
1152
1153                 while ( $row = $this->fetchObject( $res ) ) {
1154                         if ( $row->Key_name == $index ) {
1155                                 return $row;
1156                         }
1157                 }
1158                 return false;
1159         }
1160
1161         /**
1162          * Query whether a given table exists
1163          */
1164         function tableExists( $table ) {
1165                 $table = $this->tableName( $table );
1166                 $old = $this->ignoreErrors( true );
1167                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1168                 $this->ignoreErrors( $old );
1169                 if( $res ) {
1170                         $this->freeResult( $res );
1171                         return true;
1172                 } else {
1173                         return false;
1174                 }
1175         }
1176
1177         /**
1178          * mysql_fetch_field() wrapper
1179          * Returns false if the field doesn't exist
1180          *
1181          * @param $table
1182          * @param $field
1183          */
1184         function fieldInfo( $table, $field ) {
1185                 $table = $this->tableName( $table );
1186                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1187                 $n = mysql_num_fields( $res );
1188                 for( $i = 0; $i < $n; $i++ ) {
1189                         $meta = mysql_fetch_field( $res, $i );
1190                         if( $field == $meta->name ) {
1191                                 return $meta;
1192                         }
1193                 }
1194                 return false;
1195         }
1196
1197         /**
1198          * mysql_field_type() wrapper
1199          */
1200         function fieldType( $res, $index ) {
1201                 return mysql_field_type( $res, $index );
1202         }
1203
1204         /**
1205          * Determines if a given index is unique
1206          */
1207         function indexUnique( $table, $index ) {
1208                 $indexInfo = $this->indexInfo( $table, $index );
1209                 if ( !$indexInfo ) {
1210                         return NULL;
1211                 }
1212                 return !$indexInfo->Non_unique;
1213         }
1214
1215         /**
1216          * INSERT wrapper, inserts an array into a table
1217          *
1218          * $a may be a single associative array, or an array of these with numeric keys, for
1219          * multi-row insert.
1220          *
1221          * Usually aborts on failure
1222          * If errors are explicitly ignored, returns success
1223          */
1224         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1225                 # No rows to insert, easy just return now
1226                 if ( !count( $a ) ) {
1227                         return true;
1228                 }
1229
1230                 $table = $this->tableName( $table );
1231                 if ( !is_array( $options ) ) {
1232                         $options = array( $options );
1233                 }
1234                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1235                         $multi = true;
1236                         $keys = array_keys( $a[0] );
1237                 } else {
1238                         $multi = false;
1239                         $keys = array_keys( $a );
1240                 }
1241
1242                 $sql = 'INSERT ' . implode( ' ', $options ) .
1243                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1244
1245                 if ( $multi ) {
1246                         $first = true;
1247                         foreach ( $a as $row ) {
1248                                 if ( $first ) {
1249                                         $first = false;
1250                                 } else {
1251                                         $sql .= ',';
1252                                 }
1253                                 $sql .= '(' . $this->makeList( $row ) . ')';
1254                         }
1255                 } else {
1256                         $sql .= '(' . $this->makeList( $a ) . ')';
1257                 }
1258                 return (bool)$this->query( $sql, $fname );
1259         }
1260
1261         /**
1262          * Make UPDATE options for the Database::update function
1263          *
1264          * @private
1265          * @param array $options The options passed to Database::update
1266          * @return string
1267          */
1268         function makeUpdateOptions( $options ) {
1269                 if( !is_array( $options ) ) {
1270                         $options = array( $options );
1271                 }
1272                 $opts = array();
1273                 if ( in_array( 'LOW_PRIORITY', $options ) )
1274                         $opts[] = $this->lowPriorityOption();
1275                 if ( in_array( 'IGNORE', $options ) )
1276                         $opts[] = 'IGNORE';
1277                 return implode(' ', $opts);
1278         }
1279
1280         /**
1281          * UPDATE wrapper, takes a condition array and a SET array
1282          *
1283          * @param string $table  The table to UPDATE
1284          * @param array  $values An array of values to SET
1285          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1286          * @param string $fname  The Class::Function calling this function
1287          *                       (for the log)
1288          * @param array  $options An array of UPDATE options, can be one or
1289          *                        more of IGNORE, LOW_PRIORITY
1290          */
1291         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1292                 $table = $this->tableName( $table );
1293                 $opts = $this->makeUpdateOptions( $options );
1294                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1295                 if ( $conds != '*' ) {
1296                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1297                 }
1298                 $this->query( $sql, $fname );
1299         }
1300
1301         /**
1302          * Makes a wfStrencoded list from an array
1303          * $mode:
1304          *        LIST_COMMA         - comma separated, no field names
1305          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1306          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1307          *        LIST_SET           - comma separated with field names, like a SET clause
1308          *        LIST_NAMES         - comma separated field names
1309          */
1310         function makeList( $a, $mode = LIST_COMMA ) {
1311                 if ( !is_array( $a ) ) {
1312                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1313                 }
1314
1315                 $first = true;
1316                 $list = '';
1317                 foreach ( $a as $field => $value ) {
1318                         if ( !$first ) {
1319                                 if ( $mode == LIST_AND ) {
1320                                         $list .= ' AND ';
1321                                 } elseif($mode == LIST_OR) {
1322                                         $list .= ' OR ';
1323                                 } else {
1324                                         $list .= ',';
1325                                 }
1326                         } else {
1327                                 $first = false;
1328                         }
1329                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1330                                 $list .= "($value)";
1331                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array ($value) ) {
1332                                 $list .= $field." IN (".$this->makeList($value).") ";
1333                         } else {
1334                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1335                                         $list .= "$field = ";
1336                                 }
1337                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1338                         }
1339                 }
1340                 return $list;
1341         }
1342
1343         /**
1344          * Change the current database
1345          */
1346         function selectDB( $db ) {
1347                 $this->mDBname = $db;
1348                 return mysql_select_db( $db, $this->mConn );
1349         }
1350
1351         /**
1352          * Format a table name ready for use in constructing an SQL query
1353          *
1354          * This does two important things: it quotes table names which as necessary,
1355          * and it adds a table prefix if there is one.
1356          *
1357          * All functions of this object which require a table name call this function
1358          * themselves. Pass the canonical name to such functions. This is only needed
1359          * when calling query() directly.
1360          *
1361          * @param string $name database table name
1362          */
1363         function tableName( $name ) {
1364                 global $wgSharedDB;
1365                 # Skip quoted literals
1366                 if ( $name{0} != '`' ) {
1367                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1368                                 $name = "{$this->mTablePrefix}$name";
1369                         }
1370                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1371                                 $name = "`$wgSharedDB`.`$name`";
1372                         } else {
1373                                 # Standard quoting
1374                                 $name = "`$name`";
1375                         }
1376                 }
1377                 return $name;
1378         }
1379
1380         /**
1381          * Fetch a number of table names into an array
1382          * This is handy when you need to construct SQL for joins
1383          *
1384          * Example:
1385          * extract($dbr->tableNames('user','watchlist'));
1386          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1387          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1388          */
1389         function tableNames() {
1390                 $inArray = func_get_args();
1391                 $retVal = array();
1392                 foreach ( $inArray as $name ) {
1393                         $retVal[$name] = $this->tableName( $name );
1394                 }
1395                 return $retVal;
1396         }
1397
1398         /**
1399          * @private
1400          */
1401         function tableNamesWithUseIndex( $tables, $use_index ) {
1402                 $ret = array();
1403
1404                 foreach ( $tables as $table )
1405                         if ( @$use_index[$table] !== null )
1406                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1407                         else
1408                                 $ret[] = $this->tableName( $table );
1409
1410                 return implode( ',', $ret );
1411         }
1412
1413         /**
1414          * Wrapper for addslashes()
1415          * @param string $s String to be slashed.
1416          * @return string slashed string.
1417          */
1418         function strencode( $s ) {
1419                 return mysql_real_escape_string( $s, $this->mConn );
1420         }
1421
1422         /**
1423          * If it's a string, adds quotes and backslashes
1424          * Otherwise returns as-is
1425          */
1426         function addQuotes( $s ) {
1427                 if ( is_null( $s ) ) {
1428                         return 'NULL';
1429                 } else {
1430                         # This will also quote numeric values. This should be harmless,
1431                         # and protects against weird problems that occur when they really
1432                         # _are_ strings such as article titles and string->number->string
1433                         # conversion is not 1:1.
1434                         return "'" . $this->strencode( $s ) . "'";
1435                 }
1436         }
1437
1438         /**
1439          * Escape string for safe LIKE usage
1440          */
1441         function escapeLike( $s ) {
1442                 $s=$this->strencode( $s );
1443                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1444                 return $s;
1445         }
1446
1447         /**
1448          * Returns an appropriately quoted sequence value for inserting a new row.
1449          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1450          * subclass will return an integer, and save the value for insertId()
1451          */
1452         function nextSequenceValue( $seqName ) {
1453                 return NULL;
1454         }
1455
1456         /**
1457          * USE INDEX clause
1458          * PostgreSQL doesn't have them and returns ""
1459          */
1460         function useIndexClause( $index ) {
1461                 return "FORCE INDEX ($index)";
1462         }
1463
1464         /**
1465          * REPLACE query wrapper
1466          * PostgreSQL simulates this with a DELETE followed by INSERT
1467          * $row is the row to insert, an associative array
1468          * $uniqueIndexes is an array of indexes. Each element may be either a
1469          * field name or an array of field names
1470          *
1471          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1472          * However if you do this, you run the risk of encountering errors which wouldn't have
1473          * occurred in MySQL
1474          *
1475          * @todo migrate comment to phodocumentor format
1476          */
1477         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1478                 $table = $this->tableName( $table );
1479
1480                 # Single row case
1481                 if ( !is_array( reset( $rows ) ) ) {
1482                         $rows = array( $rows );
1483                 }
1484
1485                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1486                 $first = true;
1487                 foreach ( $rows as $row ) {
1488                         if ( $first ) {
1489                                 $first = false;
1490                         } else {
1491                                 $sql .= ',';
1492                         }
1493                         $sql .= '(' . $this->makeList( $row ) . ')';
1494                 }
1495                 return $this->query( $sql, $fname );
1496         }
1497
1498         /**
1499          * DELETE where the condition is a join
1500          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1501          *
1502          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1503          * join condition matches, set $conds='*'
1504          *
1505          * DO NOT put the join condition in $conds
1506          *
1507          * @param string $delTable The table to delete from.
1508          * @param string $joinTable The other table.
1509          * @param string $delVar The variable to join on, in the first table.
1510          * @param string $joinVar The variable to join on, in the second table.
1511          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1512          */
1513         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1514                 if ( !$conds ) {
1515                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1516                 }
1517
1518                 $delTable = $this->tableName( $delTable );
1519                 $joinTable = $this->tableName( $joinTable );
1520                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1521                 if ( $conds != '*' ) {
1522                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1523                 }
1524
1525                 return $this->query( $sql, $fname );
1526         }
1527
1528         /**
1529          * Returns the size of a text field, or -1 for "unlimited"
1530          */
1531         function textFieldSize( $table, $field ) {
1532                 $table = $this->tableName( $table );
1533                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1534                 $res = $this->query( $sql, 'Database::textFieldSize' );
1535                 $row = $this->fetchObject( $res );
1536                 $this->freeResult( $res );
1537
1538                 if ( preg_match( "/\((.*)\)/", $row->Type, $m ) ) {
1539                         $size = $m[1];
1540                 } else {
1541                         $size = -1;
1542                 }
1543                 return $size;
1544         }
1545
1546         /**
1547          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1548          */
1549         function lowPriorityOption() {
1550                 return 'LOW_PRIORITY';
1551         }
1552
1553         /**
1554          * DELETE query wrapper
1555          *
1556          * Use $conds == "*" to delete all rows
1557          */
1558         function delete( $table, $conds, $fname = 'Database::delete' ) {
1559                 if ( !$conds ) {
1560                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1561                 }
1562                 $table = $this->tableName( $table );
1563                 $sql = "DELETE FROM $table";
1564                 if ( $conds != '*' ) {
1565                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1566                 }
1567                 return $this->query( $sql, $fname );
1568         }
1569
1570         /**
1571          * INSERT SELECT wrapper
1572          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1573          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1574          * $conds may be "*" to copy the whole table
1575          * srcTable may be an array of tables.
1576          */
1577         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1578                 $insertOptions = array(), $selectOptions = array() )
1579         {
1580                 $destTable = $this->tableName( $destTable );
1581                 if ( is_array( $insertOptions ) ) {
1582                         $insertOptions = implode( ' ', $insertOptions );
1583                 }
1584                 if( !is_array( $selectOptions ) ) {
1585                         $selectOptions = array( $selectOptions );
1586                 }
1587                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1588                 if( is_array( $srcTable ) ) {
1589                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1590                 } else {
1591                         $srcTable = $this->tableName( $srcTable );
1592                 }
1593                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1594                         " SELECT $startOpts " . implode( ',', $varMap ) .
1595                         " FROM $srcTable $useIndex ";
1596                 if ( $conds != '*' ) {
1597                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1598                 }
1599                 $sql .= " $tailOpts";
1600                 return $this->query( $sql, $fname );
1601         }
1602
1603         /**
1604          * Construct a LIMIT query with optional offset
1605          * This is used for query pages
1606          * $sql string SQL query we will append the limit too
1607          * $limit integer the SQL limit
1608          * $offset integer the SQL offset (default false)
1609          */
1610         function limitResult($sql, $limit, $offset=false) {
1611                 if( !is_numeric($limit) ) {
1612                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1613                 }
1614                 return " $sql LIMIT "
1615                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1616                                 . "{$limit} ";
1617         }
1618         function limitResultForUpdate($sql, $num) {
1619                 return $this->limitResult($sql, $num, 0);
1620         }
1621
1622         /**
1623          * Returns an SQL expression for a simple conditional.
1624          * Uses IF on MySQL.
1625          *
1626          * @param string $cond SQL expression which will result in a boolean value
1627          * @param string $trueVal SQL expression to return if true
1628          * @param string $falseVal SQL expression to return if false
1629          * @return string SQL fragment
1630          */
1631         function conditional( $cond, $trueVal, $falseVal ) {
1632                 return " IF($cond, $trueVal, $falseVal) ";
1633         }
1634
1635         /**
1636          * Determines if the last failure was due to a deadlock
1637          */
1638         function wasDeadlock() {
1639                 return $this->lastErrno() == 1213;
1640         }
1641
1642         /**
1643          * Perform a deadlock-prone transaction.
1644          *
1645          * This function invokes a callback function to perform a set of write
1646          * queries. If a deadlock occurs during the processing, the transaction
1647          * will be rolled back and the callback function will be called again.
1648          *
1649          * Usage:
1650          *   $dbw->deadlockLoop( callback, ... );
1651          *
1652          * Extra arguments are passed through to the specified callback function.
1653          *
1654          * Returns whatever the callback function returned on its successful,
1655          * iteration, or false on error, for example if the retry limit was
1656          * reached.
1657          */
1658         function deadlockLoop() {
1659                 $myFname = 'Database::deadlockLoop';
1660
1661                 $this->begin();
1662                 $args = func_get_args();
1663                 $function = array_shift( $args );
1664                 $oldIgnore = $this->ignoreErrors( true );
1665                 $tries = DEADLOCK_TRIES;
1666                 if ( is_array( $function ) ) {
1667                         $fname = $function[0];
1668                 } else {
1669                         $fname = $function;
1670                 }
1671                 do {
1672                         $retVal = call_user_func_array( $function, $args );
1673                         $error = $this->lastError();
1674                         $errno = $this->lastErrno();
1675                         $sql = $this->lastQuery();
1676
1677                         if ( $errno ) {
1678                                 if ( $this->wasDeadlock() ) {
1679                                         # Retry
1680                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1681                                 } else {
1682                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1683                                 }
1684                         }
1685                 } while( $this->wasDeadlock() && --$tries > 0 );
1686                 $this->ignoreErrors( $oldIgnore );
1687                 if ( $tries <= 0 ) {
1688                         $this->query( 'ROLLBACK', $myFname );
1689                         $this->reportQueryError( $error, $errno, $sql, $fname );
1690                         return false;
1691                 } else {
1692                         $this->query( 'COMMIT', $myFname );
1693                         return $retVal;
1694                 }
1695         }
1696
1697         /**
1698          * Do a SELECT MASTER_POS_WAIT()
1699          *
1700          * @param string $file the binlog file
1701          * @param string $pos the binlog position
1702          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1703          */
1704         function masterPosWait( $file, $pos, $timeout ) {
1705                 $fname = 'Database::masterPosWait';
1706                 wfProfileIn( $fname );
1707
1708
1709                 # Commit any open transactions
1710                 $this->immediateCommit();
1711
1712                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1713                 $encFile = $this->strencode( $file );
1714                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1715                 $res = $this->doQuery( $sql );
1716                 if ( $res && $row = $this->fetchRow( $res ) ) {
1717                         $this->freeResult( $res );
1718                         wfProfileOut( $fname );
1719                         return $row[0];
1720                 } else {
1721                         wfProfileOut( $fname );
1722                         return false;
1723                 }
1724         }
1725
1726         /**
1727          * Get the position of the master from SHOW SLAVE STATUS
1728          */
1729         function getSlavePos() {
1730                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1731                 $row = $this->fetchObject( $res );
1732                 if ( $row ) {
1733                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1734                 } else {
1735                         return array( false, false );
1736                 }
1737         }
1738
1739         /**
1740          * Get the position of the master from SHOW MASTER STATUS
1741          */
1742         function getMasterPos() {
1743                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1744                 $row = $this->fetchObject( $res );
1745                 if ( $row ) {
1746                         return array( $row->File, $row->Position );
1747                 } else {
1748                         return array( false, false );
1749                 }
1750         }
1751
1752         /**
1753          * Begin a transaction, committing any previously open transaction
1754          */
1755         function begin( $fname = 'Database::begin' ) {
1756                 $this->query( 'BEGIN', $fname );
1757                 $this->mTrxLevel = 1;
1758         }
1759
1760         /**
1761          * End a transaction
1762          */
1763         function commit( $fname = 'Database::commit' ) {
1764                 $this->query( 'COMMIT', $fname );
1765                 $this->mTrxLevel = 0;
1766         }
1767
1768         /**
1769          * Rollback a transaction
1770          */
1771         function rollback( $fname = 'Database::rollback' ) {
1772                 $this->query( 'ROLLBACK', $fname );
1773                 $this->mTrxLevel = 0;
1774         }
1775
1776         /**
1777          * Begin a transaction, committing any previously open transaction
1778          * @deprecated use begin()
1779          */
1780         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1781                 $this->begin();
1782         }
1783
1784         /**
1785          * Commit transaction, if one is open
1786          * @deprecated use commit()
1787          */
1788         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1789                 $this->commit();
1790         }
1791
1792         /**
1793          * Return MW-style timestamp used for MySQL schema
1794          */
1795         function timestamp( $ts=0 ) {
1796                 return wfTimestamp(TS_MW,$ts);
1797         }
1798
1799         /**
1800          * Local database timestamp format or null
1801          */
1802         function timestampOrNull( $ts = null ) {
1803                 if( is_null( $ts ) ) {
1804                         return null;
1805                 } else {
1806                         return $this->timestamp( $ts );
1807                 }
1808         }
1809
1810         /**
1811          * @todo document
1812          */
1813         function resultObject( $result ) {
1814                 if( empty( $result ) ) {
1815                         return NULL;
1816                 } else {
1817                         return new ResultWrapper( $this, $result );
1818                 }
1819         }
1820
1821         /**
1822          * Return aggregated value alias
1823          */
1824         function aggregateValue ($valuedata,$valuename='value') {
1825                 return $valuename;
1826         }
1827
1828         /**
1829          * @return string wikitext of a link to the server software's web site
1830          */
1831         function getSoftwareLink() {
1832                 return "[http://www.mysql.com/ MySQL]";
1833         }
1834
1835         /**
1836          * @return string Version information from the database
1837          */
1838         function getServerVersion() {
1839                 return mysql_get_server_info();
1840         }
1841
1842         /**
1843          * Ping the server and try to reconnect if it there is no connection
1844          */
1845         function ping() {
1846                 if( function_exists( 'mysql_ping' ) ) {
1847                         return mysql_ping( $this->mConn );
1848                 } else {
1849                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1850                         return true;
1851                 }
1852         }
1853
1854         /**
1855          * Get slave lag.
1856          * At the moment, this will only work if the DB user has the PROCESS privilege
1857          */
1858         function getLag() {
1859                 $res = $this->query( 'SHOW PROCESSLIST' );
1860                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1861                 # dubious, but unfortunately there's no easy rigorous way
1862                 $slaveThreads = 0;
1863                 while ( $row = $this->fetchObject( $res ) ) {
1864                         /* This should work for most situations - when default db
1865                          * for thread is not specified, it had no events executed,
1866                          * and therefore it doesn't know yet how lagged it is.
1867                          *
1868                          * Relay log I/O thread does not select databases.
1869                          */
1870                         if ( $row->User == 'system user' &&
1871                                 $row->State != 'Waiting for master to send event' &&
1872                                 $row->State != 'Connecting to master' &&
1873                                 $row->State != 'Queueing master event to the relay log' &&
1874                                 $row->State != 'Waiting for master update' &&
1875                                 $row->State != 'Requesting binlog dump'
1876                                 ) {
1877                                 # This is it, return the time (except -ve)
1878                                 if ( $row->Time > 0x7fffffff ) {
1879                                         return false;
1880                                 } else {
1881                                         return $row->Time;
1882                                 }
1883                         }
1884                 }
1885                 return false;
1886         }
1887
1888         /**
1889          * Get status information from SHOW STATUS in an associative array
1890          */
1891         function getStatus($which="%") {
1892                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1893                 $status = array();
1894                 while ( $row = $this->fetchObject( $res ) ) {
1895                         $status[$row->Variable_name] = $row->Value;
1896                 }
1897                 return $status;
1898         }
1899
1900         /**
1901          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1902          */
1903         function maxListLen() {
1904                 return 0;
1905         }
1906
1907         function encodeBlob($b) {
1908                 return $b;
1909         }
1910
1911         function decodeBlob($b) {
1912                 return $b;
1913         }
1914
1915         /**
1916          * Read and execute SQL commands from a file.
1917          * Returns true on success, error string on failure
1918          */
1919         function sourceFile( $filename ) {
1920                 $fp = fopen( $filename, 'r' );
1921                 if ( false === $fp ) {
1922                         return "Could not open \"{$filename}\".\n";
1923                 }
1924
1925                 $cmd = "";
1926                 $done = false;
1927                 $dollarquote = false;
1928
1929                 while ( ! feof( $fp ) ) {
1930                         $line = trim( fgets( $fp, 1024 ) );
1931                         $sl = strlen( $line ) - 1;
1932
1933                         if ( $sl < 0 ) { continue; }
1934                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
1935
1936                         ## Allow dollar quoting for function declarations
1937                         if (substr($line,0,4) == '$mw$') {
1938                                 if ($dollarquote) {
1939                                         $dollarquote = false;
1940                                         $done = true;
1941                                 }
1942                                 else {
1943                                         $dollarquote = true;
1944                                 }
1945                         }
1946                         else if (!$dollarquote) {
1947                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
1948                                         $done = true;
1949                                         $line = substr( $line, 0, $sl );
1950                                 }
1951                         }
1952
1953                         if ( '' != $cmd ) { $cmd .= ' '; }
1954                         $cmd .= "$line\n";
1955
1956                         if ( $done ) {
1957                                 $cmd = str_replace(';;', ";", $cmd);
1958                                 $cmd = $this->replaceVars( $cmd );
1959                                 $res = $this->query( $cmd, 'dbsource', true );
1960
1961                                 if ( false === $res ) {
1962                                         $err = $this->lastError();
1963                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
1964                                 }
1965
1966                                 $cmd = '';
1967                                 $done = false;
1968                         }
1969                 }
1970                 fclose( $fp );
1971                 return true;
1972         }
1973
1974         /**
1975          * Replace variables in sourced SQL
1976          */
1977         protected function replaceVars( $ins ) {
1978                 $varnames = array(
1979                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
1980                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
1981                         'wgDBadminuser', 'wgDBadminpassword',
1982                 );
1983
1984                 // Ordinary variables
1985                 foreach ( $varnames as $var ) {
1986                         if( isset( $GLOBALS[$var] ) ) {
1987                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
1988                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
1989                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
1990                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
1991                         }
1992                 }
1993
1994                 // Table prefixes
1995                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
1996                         array( &$this, 'tableNameCallback' ), $ins );
1997                 return $ins;
1998         }
1999
2000         /**
2001          * Table name callback
2002          * @private
2003          */
2004         protected function tableNameCallback( $matches ) {
2005                 return $this->tableName( $matches[1] );
2006         }
2007
2008 }
2009
2010 /**
2011  * Database abstraction object for mySQL
2012  * Inherit all methods and properties of Database::Database()
2013  *
2014  * @package MediaWiki
2015  * @see Database
2016  */
2017 class DatabaseMysql extends Database {
2018         # Inherit all
2019 }
2020
2021
2022 /**
2023  * Result wrapper for grabbing data queried by someone else
2024  *
2025  * @package MediaWiki
2026  */
2027 class ResultWrapper {
2028         var $db, $result;
2029
2030         /**
2031          * @todo document
2032          */
2033         function ResultWrapper( &$database, $result ) {
2034                 $this->db =& $database;
2035                 $this->result =& $result;
2036         }
2037
2038         /**
2039          * @todo document
2040          */
2041         function numRows() {
2042                 return $this->db->numRows( $this->result );
2043         }
2044
2045         /**
2046          * @todo document
2047          */
2048         function fetchObject() {
2049                 return $this->db->fetchObject( $this->result );
2050         }
2051
2052         /**
2053          * @todo document
2054          */
2055         function fetchRow() {
2056                 return $this->db->fetchRow( $this->result );
2057         }
2058
2059         /**
2060          * @todo document
2061          */
2062         function free() {
2063                 $this->db->freeResult( $this->result );
2064                 unset( $this->result );
2065                 unset( $this->db );
2066         }
2067
2068         function seek( $row ) {
2069                 $this->db->dataSeek( $this->result, $row );
2070         }
2071
2072 }
2073
2074 ?>