includes/db/Database.php

   1 <?php
   2 /**
   3  * @defgroup Database Database
   4  *
   5  * @file
   6  * @ingroup Database
   7  * This file deals with database interface functions
   8  * and query specifics/optimisations
   9  */
  10
  11 /** Number of times to re-try an operation in case of deadlock */
  12 define( 'DEADLOCK_TRIES', 4 );
  13 /** Minimum time to wait before retry, in microseconds */
  14 define( 'DEADLOCK_DELAY_MIN', 500000 );
  15 /** Maximum time to wait before retry */
  16 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  17
  18 /**
  19  * Database abstraction object
  20  * @ingroup Database
  21  */
  22 abstract class DatabaseBase {
  23
  24 #------------------------------------------------------------------------------
  25 # Variables
  26 #------------------------------------------------------------------------------
  27
  28         protected $mLastQuery = '';
  29         protected $mDoneWrites = false;
  30         protected $mPHPError = false;
  31
  32         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  33         protected $mOpened = false;
  34
  35         protected $mFailFunction;
  36         protected $mTablePrefix;
  37         protected $mFlags;
  38         protected $mTrxLevel = 0;
  39         protected $mErrorCount = 0;
  40         protected $mLBInfo = array();
  41         protected $mFakeSlaveLag = null, $mFakeMaster = false;
  42         protected $mDefaultBigSelects = null;
  43
  44 #------------------------------------------------------------------------------
  45 # Accessors
  46 #------------------------------------------------------------------------------
  47         # These optionally set a variable and return the previous state
  48
  49         /**
  50          * Fail function, takes a Database as a parameter
  51          * Set to false for default, 1 for ignore errors
  52          */
  53         function failFunction( $function = null ) {
  54                 return wfSetVar( $this->mFailFunction, $function );
  55         }
  56
  57         /**
  58          * Boolean, controls output of large amounts of debug information
  59          */
  60         function debug( $debug = null ) {
  61                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  62         }
  63
  64         /**
  65          * Turns buffering of SQL result sets on (true) or off (false).
  66          * Default is "on" and it should not be changed without good reasons.
  67          */
  68         function bufferResults( $buffer = null ) {
  69                 if ( is_null( $buffer ) ) {
  70                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  71                 } else {
  72                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  73                 }
  74         }
  75
  76         /**
  77          * Turns on (false) or off (true) the automatic generation and sending
  78          * of a "we're sorry, but there has been a database error" page on
  79          * database errors. Default is on (false). When turned off, the
  80          * code should use lastErrno() and lastError() to handle the
  81          * situation as appropriate.
  82          */
  83         function ignoreErrors( $ignoreErrors = null ) {
  84                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  85         }
  86
  87         /**
  88          * The current depth of nested transactions
  89          * @param $level Integer: , default NULL.
  90          */
  91         function trxLevel( $level = null ) {
  92                 return wfSetVar( $this->mTrxLevel, $level );
  93         }
  94
  95         /**
  96          * Number of errors logged, only useful when errors are ignored
  97          */
  98         function errorCount( $count = null ) {
  99                 return wfSetVar( $this->mErrorCount, $count );
 100         }
 101
 102         function tablePrefix( $prefix = null ) {
 103                 return wfSetVar( $this->mTablePrefix, $prefix );
 104         }
 105
 106         /**
 107          * Properties passed down from the server info array of the load balancer
 108          */
 109         function getLBInfo( $name = null ) {
 110                 if ( is_null( $name ) ) {
 111                         return $this->mLBInfo;
 112                 } else {
 113                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 114                                 return $this->mLBInfo[$name];
 115                         } else {
 116                                 return null;
 117                         }
 118                 }
 119         }
 120
 121         function setLBInfo( $name, $value = null ) {
 122                 if ( is_null( $value ) ) {
 123                         $this->mLBInfo = $name;
 124                 } else {
 125                         $this->mLBInfo[$name] = $value;
 126                 }
 127         }
 128
 129         /**
 130          * Set lag time in seconds for a fake slave
 131          */
 132         function setFakeSlaveLag( $lag ) {
 133                 $this->mFakeSlaveLag = $lag;
 134         }
 135
 136         /**
 137          * Make this connection a fake master
 138          */
 139         function setFakeMaster( $enabled = true ) {
 140                 $this->mFakeMaster = $enabled;
 141         }
 142
 143         /**
 144          * Returns true if this database supports (and uses) cascading deletes
 145          */
 146         function cascadingDeletes() {
 147                 return false;
 148         }
 149
 150         /**
 151          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 152          */
 153         function cleanupTriggers() {
 154                 return false;
 155         }
 156
 157         /**
 158          * Returns true if this database is strict about what can be put into an IP field.
 159          * Specifically, it uses a NULL value instead of an empty string.
 160          */
 161         function strictIPs() {
 162                 return false;
 163         }
 164
 165         /**
 166          * Returns true if this database uses timestamps rather than integers
 167         */
 168         function realTimestamps() {
 169                 return false;
 170         }
 171
 172         /**
 173          * Returns true if this database does an implicit sort when doing GROUP BY
 174          */
 175         function implicitGroupby() {
 176                 return true;
 177         }
 178
 179         /**
 180          * Returns true if this database does an implicit order by when the column has an index
 181          * For example: SELECT page_title FROM page LIMIT 1
 182          */
 183         function implicitOrderby() {
 184                 return true;
 185         }
 186
 187         /**
 188          * Returns true if this database requires that SELECT DISTINCT queries require that all
 189        ORDER BY expressions occur in the SELECT list per the SQL92 standard
 190          */
 191         function standardSelectDistinct() {
 192                 return true;
 193         }
 194
 195         /**
 196          * Returns true if this database can do a native search on IP columns
 197          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 198          */
 199         function searchableIPs() {
 200                 return false;
 201         }
 202
 203         /**
 204          * Returns true if this database can use functional indexes
 205          */
 206         function functionalIndexes() {
 207                 return false;
 208         }
 209
 210         /**
 211          * Return the last query that went through DatabaseBase::query()
 212          * @return String
 213          */
 214         function lastQuery() { return $this->mLastQuery; }
 215
 216
 217         /**
 218          * Returns true if the connection may have been used for write queries.
 219          * Should return true if unsure.
 220          */
 221         function doneWrites() { return $this->mDoneWrites; }
 222
 223         /**
 224          * Is a connection to the database open?
 225          * @return Boolean
 226          */
 227         function isOpen() { return $this->mOpened; }
 228
 229         /**
 230          * Set a flag for this connection
 231          *
 232          * @param $flag Integer: DBO_* constants from Defines.php:
 233          *   - DBO_DEBUG: output some debug info (same as debug())
 234          *   - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
 235          *   - DBO_IGNORE: ignore errors (same as ignoreErrors())
 236          *   - DBO_TRX: automatically start transactions
 237          *   - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
 238          *       and removes it in command line mode
 239          *   - DBO_PERSISTENT: use persistant database connection
 240          */
 241         function setFlag( $flag ) {
 242                 $this->mFlags |= $flag;
 243         }
 244
 245         /**
 246          * Clear a flag for this connection
 247          *
 248          * @param $flag: same as setFlag()'s $flag param
 249          */
 250         function clearFlag( $flag ) {
 251                 $this->mFlags &= ~$flag;
 252         }
 253
 254         /**
 255          * Returns a boolean whether the flag $flag is set for this connection
 256          *
 257          * @param $flag: same as setFlag()'s $flag param
 258          * @return Boolean
 259          */
 260         function getFlag( $flag ) {
 261                 return !!($this->mFlags & $flag);
 262         }
 263
 264         /**
 265          * General read-only accessor
 266          */
 267         function getProperty( $name ) {
 268                 return $this->$name;
 269         }
 270
 271         function getWikiID() {
 272                 if( $this->mTablePrefix ) {
 273                         return "{$this->mDBname}-{$this->mTablePrefix}";
 274                 } else {
 275                         return $this->mDBname;
 276                 }
 277         }
 278
 279         /**
 280          * Get the type of the DBMS, as it appears in $wgDBtype.
 281          */
 282         abstract function getType();
 283
 284 #------------------------------------------------------------------------------
 285 # Other functions
 286 #------------------------------------------------------------------------------
 287
 288         /**
 289          * Constructor.
 290          * @param $server String: database server host
 291          * @param $user String: database user name
 292          * @param $password String: database user password
 293          * @param $dbName String: database name
 294          * @param $failFunction
 295          * @param $flags
 296          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 297          */
 298         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 299                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 300
 301                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 302                 # Can't get a reference if it hasn't been set yet
 303                 if ( !isset( $wgOut ) ) {
 304                         $wgOut = null;
 305                 }
 306
 307                 $this->mFailFunction = $failFunction;
 308                 $this->mFlags = $flags;
 309
 310                 if ( $this->mFlags & DBO_DEFAULT ) {
 311                         if ( $wgCommandLineMode ) {
 312                                 $this->mFlags &= ~DBO_TRX;
 313                         } else {
 314                                 $this->mFlags |= DBO_TRX;
 315                         }
 316                 }
 317
 318                 /*
 319                 // Faster read-only access
 320                 if ( wfReadOnly() ) {
 321                         $this->mFlags |= DBO_PERSISTENT;
 322                         $this->mFlags &= ~DBO_TRX;
 323                 }*/
 324
 325                 /** Get the default table prefix*/
 326                 if ( $tablePrefix == 'get from global' ) {
 327                         $this->mTablePrefix = $wgDBprefix;
 328                 } else {
 329                         $this->mTablePrefix = $tablePrefix;
 330                 }
 331
 332                 if ( $server ) {
 333                         $this->open( $server, $user, $password, $dbName );
 334                 }
 335         }
 336
 337         /**
 338          * Same as new DatabaseMysql( ... ), kept for backward compatibility
 339          * @param $server String: database server host
 340          * @param $user String: database user name
 341          * @param $password String: database user password
 342          * @param $dbName String: database name
 343          * @param failFunction
 344          * @param $flags
 345          */
 346         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 347         {
 348                 wfDeprecated( __METHOD__ );
 349                 return new DatabaseMysql( $server, $user, $password, $dbName, $failFunction, $flags );
 350         }
 351
 352         /**
 353          * Usually aborts on failure
 354          * If the failFunction is set to a non-zero integer, returns success
 355          * @param $server String: database server host
 356          * @param $user String: database user name
 357          * @param $password String: database user password
 358          * @param $dbName String: database name
 359          */
 360         abstract function open( $server, $user, $password, $dbName );
 361
 362         protected function installErrorHandler() {
 363                 $this->mPHPError = false;
 364                 $this->htmlErrors = ini_set( 'html_errors', '0' );
 365                 set_error_handler( array( $this, 'connectionErrorHandler' ) );
 366         }
 367
 368         protected function restoreErrorHandler() {
 369                 restore_error_handler();
 370                 if ( $this->htmlErrors !== false ) {
 371                         ini_set( 'html_errors', $this->htmlErrors );
 372                 }
 373                 if ( $this->mPHPError ) {
 374                         $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
 375                         $error = preg_replace( '!^.*?:(.*)$!', '$1', $error );
 376                         return $error;
 377                 } else {
 378                         return false;
 379                 }
 380         }
 381
 382         protected function connectionErrorHandler( $errno,  $errstr ) {
 383                 $this->mPHPError = $errstr;
 384         }
 385
 386         /**
 387          * Closes a database connection.
 388          * if it is open : commits any open transactions
 389          *
 390          * @return Bool operation success. true if already closed.
 391          */
 392         function close() {
 393                 # Stub, should probably be overridden
 394                 return true;
 395         }
 396
 397         /**
 398          * @param $error String: fallback error message, used if none is given by DB
 399          */
 400         function reportConnectionError( $error = 'Unknown error' ) {
 401                 $myError = $this->lastError();
 402                 if ( $myError ) {
 403                         $error = $myError;
 404                 }
 405
 406                 if ( $this->mFailFunction ) {
 407                         # Legacy error handling method
 408                         if ( !is_int( $this->mFailFunction ) ) {
 409                                 $ff = $this->mFailFunction;
 410                                 $ff( $this, $error );
 411                         }
 412                 } else {
 413                         # New method
 414                         throw new DBConnectionError( $this, $error );
 415                 }
 416         }
 417
 418         /**
 419          * Determine whether a query writes to the DB.
 420          * Should return true if unsure.
 421          */
 422         function isWriteQuery( $sql ) {
 423                 return !preg_match( '/^(?:SELECT|BEGIN|COMMIT|SET|SHOW|\(SELECT)\b/i', $sql );
 424         }
 425
 426         /**
 427          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 428          *
 429          * @param  $sql        String: SQL query
 430          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 431          *     comment (you can use __METHOD__ or add some extra info)
 432          * @param  $tempIgnore Boolean:   Whether to avoid throwing an exception on errors...
 433          *     maybe best to catch the exception instead?
 434          * @return true for a successful write query, ResultWrapper object for a successful read query,
 435          *     or false on failure if $tempIgnore set
 436          * @throws DBQueryError Thrown when the database returns an error of any kind
 437          */
 438         public function query( $sql, $fname = '', $tempIgnore = false ) {
 439                 global $wgProfiler;
 440
 441                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 442                 if ( isset( $wgProfiler ) ) {
 443                         # generalizeSQL will probably cut down the query to reasonable
 444                         # logging size most of the time. The substr is really just a sanity check.
 445
 446                         # Who's been wasting my precious column space? -- TS
 447                         #$profName = 'query: ' . $fname . ' ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
 448
 449                         if ( $isMaster ) {
 450                                 $queryProf = 'query-m: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
 451                                 $totalProf = 'DatabaseBase::query-master';
 452                         } else {
 453                                 $queryProf = 'query: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
 454                                 $totalProf = 'DatabaseBase::query';
 455                         }
 456                         wfProfileIn( $totalProf );
 457                         wfProfileIn( $queryProf );
 458                 }
 459
 460                 $this->mLastQuery = $sql;
 461                 if ( !$this->mDoneWrites && $this->isWriteQuery( $sql ) ) {
 462                         // Set a flag indicating that writes have been done
 463                         wfDebug( __METHOD__.": Writes done: $sql\n" );
 464                         $this->mDoneWrites = true;
 465                 }
 466
 467                 # Add a comment for easy SHOW PROCESSLIST interpretation
 468                 #if ( $fname ) {
 469                         global $wgUser;
 470                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 471                                 $userName = $wgUser->getName();
 472                                 if ( mb_strlen( $userName ) > 15 ) {
 473                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 474                                 }
 475                                 $userName = str_replace( '/', '', $userName );
 476                         } else {
 477                                 $userName = '';
 478                         }
 479                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 480                 #} else {
 481                 #       $commentedSql = $sql;
 482                 #}
 483
 484                 # If DBO_TRX is set, start a transaction
 485                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 486                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 487                         // avoid establishing transactions for SHOW and SET statements too -
 488                         // that would delay transaction initializations to once connection
 489                         // is really used by application
 490                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 491                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 492                                 $this->begin();
 493                 }
 494
 495                 if ( $this->debug() ) {
 496                         static $cnt = 0;
 497                         $cnt++;
 498                         $sqlx = substr( $commentedSql, 0, 500 );
 499                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 500                         if ( $isMaster ) {
 501                                 wfDebug( "Query $cnt (master): $sqlx\n" );
 502                         } else {
 503                                 wfDebug( "Query $cnt (slave): $sqlx\n" );
 504                         }
 505                 }
 506
 507                 if ( istainted( $sql ) & TC_MYSQL ) {
 508                         throw new MWException( 'Tainted query found' );
 509                 }
 510
 511                 # Do the query and handle errors
 512                 $ret = $this->doQuery( $commentedSql );
 513
 514                 # Try reconnecting if the connection was lost
 515                 if ( false === $ret && $this->wasErrorReissuable() ) {
 516                         # Transaction is gone, like it or not
 517                         $this->mTrxLevel = 0;
 518                         wfDebug( "Connection lost, reconnecting...\n" );
 519                         if ( $this->ping() ) {
 520                                 wfDebug( "Reconnected\n" );
 521                                 $sqlx = substr( $commentedSql, 0, 500 );
 522                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 523                                 global $wgRequestTime;
 524                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 525                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 526                                 $ret = $this->doQuery( $commentedSql );
 527                         } else {
 528                                 wfDebug( "Failed\n" );
 529                         }
 530                 }
 531
 532                 if ( false === $ret ) {
 533                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 534                 }
 535
 536                 if ( isset( $wgProfiler ) ) {
 537                         wfProfileOut( $queryProf );
 538                         wfProfileOut( $totalProf );
 539                 }
 540                 return $this->resultObject( $ret );
 541         }
 542
 543         /**
 544          * The DBMS-dependent part of query()
 545          * @param  $sql String: SQL query.
 546          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 547          * @private
 548          */
 549         /*private*/ abstract function doQuery( $sql );
 550
 551         /**
 552          * @param $error String
 553          * @param $errno Integer
 554          * @param $sql String
 555          * @param $fname String
 556          * @param $tempIgnore Boolean
 557          */
 558         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 559                 # Ignore errors during error handling to avoid infinite recursion
 560                 $ignore = $this->ignoreErrors( true );
 561                 ++$this->mErrorCount;
 562
 563                 if( $ignore || $tempIgnore ) {
 564                         wfDebug("SQL ERROR (ignored): $error\n");
 565                         $this->ignoreErrors( $ignore );
 566                 } else {
 567                         $sql1line = str_replace( "\n", "\\n", $sql );
 568                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 569                         wfDebug("SQL ERROR: " . $error . "\n");
 570                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 571                 }
 572         }
 573
 574
 575         /**
 576          * Intended to be compatible with the PEAR::DB wrapper functions.
 577          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 578          *
 579          * ? = scalar value, quoted as necessary
 580          * ! = raw SQL bit (a function for instance)
 581          * & = filename; reads the file and inserts as a blob
 582          *     (we don't use this though...)
 583          */
 584         function prepare( $sql, $func = 'DatabaseBase::prepare' ) {
 585                 /* MySQL doesn't support prepared statements (yet), so just
 586                    pack up the query for reference. We'll manually replace
 587                    the bits later. */
 588                 return array( 'query' => $sql, 'func' => $func );
 589         }
 590
 591         function freePrepared( $prepared ) {
 592                 /* No-op by default */
 593         }
 594
 595         /**
 596          * Execute a prepared query with the various arguments
 597          * @param $prepared String: the prepared sql
 598          * @param $args Mixed: Either an array here, or put scalars as varargs
 599          */
 600         function execute( $prepared, $args = null ) {
 601                 if( !is_array( $args ) ) {
 602                         # Pull the var args
 603                         $args = func_get_args();
 604                         array_shift( $args );
 605                 }
 606                 $sql = $this->fillPrepared( $prepared['query'], $args );
 607                 return $this->query( $sql, $prepared['func'] );
 608         }
 609
 610         /**
 611          * Prepare & execute an SQL statement, quoting and inserting arguments
 612          * in the appropriate places.
 613          * @param $query String
 614          * @param $args ...
 615          */
 616         function safeQuery( $query, $args = null ) {
 617                 $prepared = $this->prepare( $query, 'DatabaseBase::safeQuery' );
 618                 if( !is_array( $args ) ) {
 619                         # Pull the var args
 620                         $args = func_get_args();
 621                         array_shift( $args );
 622                 }
 623                 $retval = $this->execute( $prepared, $args );
 624                 $this->freePrepared( $prepared );
 625                 return $retval;
 626         }
 627
 628         /**
 629          * For faking prepared SQL statements on DBs that don't support
 630          * it directly.
 631          * @param $preparedQuery String: a 'preparable' SQL statement
 632          * @param $args Array of arguments to fill it with
 633          * @return string executable SQL
 634          */
 635         function fillPrepared( $preparedQuery, $args ) {
 636                 reset( $args );
 637                 $this->preparedArgs =& $args;
 638                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 639                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 640         }
 641
 642         /**
 643          * preg_callback func for fillPrepared()
 644          * The arguments should be in $this->preparedArgs and must not be touched
 645          * while we're doing this.
 646          *
 647          * @param $matches Array
 648          * @return String
 649          * @private
 650          */
 651         function fillPreparedArg( $matches ) {
 652                 switch( $matches[1] ) {
 653                         case '\\?': return '?';
 654                         case '\\!': return '!';
 655                         case '\\&': return '&';
 656                 }
 657                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 658                 switch( $matches[1] ) {
 659                         case '?': return $this->addQuotes( $arg );
 660                         case '!': return $arg;
 661                         case '&':
 662                                 # return $this->addQuotes( file_get_contents( $arg ) );
 663                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 664                         default:
 665                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 666                 }
 667         }
 668
 669         /**
 670          * Free a result object
 671          * @param $res Mixed: A SQL result
 672          */
 673         function freeResult( $res ) {
 674                 # Stub.  Might not really need to be overridden, since results should
 675                 # be freed by PHP when the variable goes out of scope anyway.
 676         }
 677
 678         /**
 679          * Fetch the next row from the given result object, in object form.
 680          * Fields can be retrieved with $row->fieldname, with fields acting like
 681          * member variables.
 682          *
 683          * @param $res SQL result object as returned from DatabaseBase::query(), etc.
 684          * @return Row object
 685          * @throws DBUnexpectedError Thrown if the database returns an error
 686          */
 687         abstract function fetchObject( $res );
 688
 689         /**
 690          * Fetch the next row from the given result object, in associative array
 691          * form.  Fields are retrieved with $row['fieldname'].
 692          *
 693          * @param $res SQL result object as returned from DatabaseBase::query(), etc.
 694          * @return Row object
 695          * @throws DBUnexpectedError Thrown if the database returns an error
 696          */
 697         abstract function fetchRow( $res );
 698
 699         /**
 700          * Get the number of rows in a result object
 701          * @param $res Mixed: A SQL result
 702          */
 703         abstract function numRows( $res );
 704
 705         /**
 706          * Get the number of fields in a result object
 707          * See documentation for mysql_num_fields()
 708          * @param $res Mixed: A SQL result
 709          */
 710         abstract function numFields( $res );
 711
 712         /**
 713          * Get a field name in a result object
 714          * See documentation for mysql_field_name():
 715          * http://www.php.net/mysql_field_name
 716          * @param $res Mixed: A SQL result
 717          * @param $n Integer
 718          */
 719         abstract function fieldName( $res, $n );
 720
 721         /**
 722          * Get the inserted value of an auto-increment row
 723          *
 724          * The value inserted should be fetched from nextSequenceValue()
 725          *
 726          * Example:
 727          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 728          * $dbw->insert('page',array('page_id' => $id));
 729          * $id = $dbw->insertId();
 730          */
 731         abstract function insertId();
 732
 733         /**
 734          * Change the position of the cursor in a result object
 735          * See mysql_data_seek()
 736          * @param $res Mixed: A SQL result
 737          * @param $row Mixed: Either MySQL row or ResultWrapper
 738          */
 739         abstract function dataSeek( $res, $row );
 740
 741         /**
 742          * Get the last error number
 743          * See mysql_errno()
 744          */
 745         abstract function lastErrno();
 746
 747         /**
 748          * Get a description of the last error
 749          * See mysql_error() for more details
 750          */
 751         abstract function lastError();
 752
 753         /**
 754          * Get the number of rows affected by the last write query
 755          * See mysql_affected_rows() for more details
 756          */
 757         abstract function affectedRows();
 758
 759         /**
 760          * Simple UPDATE wrapper
 761          * Usually aborts on failure
 762          * If errors are explicitly ignored, returns success
 763          *
 764          * This function exists for historical reasons, DatabaseBase::update() has a more standard
 765          * calling convention and feature set
 766          */
 767         function set( $table, $var, $value, $cond, $fname = 'DatabaseBase::set' ) {
 768                 $table = $this->tableName( $table );
 769                 $sql = "UPDATE $table SET $var = '" .
 770                   $this->strencode( $value ) . "' WHERE ($cond)";
 771                 return (bool)$this->query( $sql, $fname );
 772         }
 773
 774         /**
 775          * Simple SELECT wrapper, returns a single field, input must be encoded
 776          * Usually aborts on failure
 777          * If errors are explicitly ignored, returns FALSE on failure
 778          */
 779         function selectField( $table, $var, $cond='', $fname = 'DatabaseBase::selectField', $options = array() ) {
 780                 if ( !is_array( $options ) ) {
 781                         $options = array( $options );
 782                 }
 783                 $options['LIMIT'] = 1;
 784
 785                 $res = $this->select( $table, $var, $cond, $fname, $options );
 786                 if ( $res === false || !$this->numRows( $res ) ) {
 787                         return false;
 788                 }
 789                 $row = $this->fetchRow( $res );
 790                 if ( $row !== false ) {
 791                         return reset( $row );
 792                 } else {
 793                         return false;
 794                 }
 795         }
 796
 797         /**
 798          * Returns an optional USE INDEX clause to go after the table, and a
 799          * string to go at the end of the query
 800          *
 801          * @private
 802          *
 803          * @param $options Array: associative array of options to be turned into
 804          *              an SQL query, valid keys are listed in the function.
 805          * @return Array
 806          */
 807         function makeSelectOptions( $options ) {
 808                 $preLimitTail = $postLimitTail = '';
 809                 $startOpts = '';
 810
 811                 $noKeyOptions = array();
 812                 foreach ( $options as $key => $option ) {
 813                         if ( is_numeric( $key ) ) {
 814                                 $noKeyOptions[$option] = true;
 815                         }
 816                 }
 817
 818                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 819                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 820                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 821
 822                 //if (isset($options['LIMIT'])) {
 823                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 824                 //              isset($options['OFFSET']) ? $options['OFFSET']
 825                 //              : false);
 826                 //}
 827
 828                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 829                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 830                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 831
 832                 # Various MySQL extensions
 833                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 834                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 835                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 836                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 837                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 838                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 839                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 840                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 841
 842                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 843                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 844                 } else {
 845                         $useIndex = '';
 846                 }
 847
 848                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 849         }
 850
 851         /**
 852          * SELECT wrapper
 853          *
 854          * @param $table   Mixed:  Array or string, table name(s) (prefix auto-added)
 855          * @param $vars    Mixed:  Array or string, field name(s) to be retrieved
 856          * @param $conds   Mixed:  Array or string, condition(s) for WHERE
 857          * @param $fname   String: Calling function name (use __METHOD__) for logs/profiling
 858          * @param $options Array:  Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 859          *                         see DatabaseBase::makeSelectOptions code for list of supported stuff
 860          * @param $join_conds Array: Associative array of table join conditions (optional)
 861          *                           (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 862          * @return mixed Database result resource (feed to DatabaseBase::fetchObject or whatever), or false on failure
 863          */
 864         function select( $table, $vars, $conds='', $fname = 'DatabaseBase::select', $options = array(), $join_conds = array() ) {
 865                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 866                 return $this->query( $sql, $fname );
 867         }
 868
 869         /**
 870          * SELECT wrapper
 871          *
 872          * @param $table   Mixed:  Array or string, table name(s) (prefix auto-added)
 873          * @param $vars    Mixed:  Array or string, field name(s) to be retrieved
 874          * @param $conds   Mixed:  Array or string, condition(s) for WHERE
 875          * @param $fname   String: Calling function name (use __METHOD__) for logs/profiling
 876          * @param $options Array:  Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 877          *                         see DatabaseBase::makeSelectOptions code for list of supported stuff
 878          * @param $join_conds Array: Associative array of table join conditions (optional)
 879          *                           (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 880          * @return string, the SQL text
 881          */
 882         function selectSQLText( $table, $vars, $conds='', $fname = 'DatabaseBase::select', $options = array(), $join_conds = array() ) {
 883                 if( is_array( $vars ) ) {
 884                         $vars = implode( ',', $vars );
 885                 }
 886                 if( !is_array( $options ) ) {
 887                         $options = array( $options );
 888                 }
 889                 if( is_array( $table ) ) {
 890                         if ( !empty($join_conds) || ( isset( $options['USE INDEX'] ) && is_array( @$options['USE INDEX'] ) ) )
 891                                 $from = ' FROM ' . $this->tableNamesWithUseIndexOrJOIN( $table, @$options['USE INDEX'], $join_conds );
 892                         else
 893                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 894                 } elseif ($table!='') {
 895                         if ($table{0}==' ') {
 896                                 $from = ' FROM ' . $table;
 897                         } else {
 898                                 $from = ' FROM ' . $this->tableName( $table );
 899                         }
 900                 } else {
 901                         $from = '';
 902                 }
 903
 904                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
 905
 906                 if( !empty( $conds ) ) {
 907                         if ( is_array( $conds ) ) {
 908                                 $conds = $this->makeList( $conds, LIST_AND );
 909                         }
 910                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
 911                 } else {
 912                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
 913                 }
 914
 915                 if (isset($options['LIMIT']))
 916                         $sql = $this->limitResult($sql, $options['LIMIT'],
 917                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 918                 $sql = "$sql $postLimitTail";
 919
 920                 if (isset($options['EXPLAIN'])) {
 921                         $sql = 'EXPLAIN ' . $sql;
 922                 }
 923                 return $sql;
 924         }
 925
 926         /**
 927          * Single row SELECT wrapper
 928          * Aborts or returns FALSE on error
 929          *
 930          * @param $table String: table name
 931          * @param $vars String: the selected variables
 932          * @param $conds Array: a condition map, terms are ANDed together.
 933          *   Items with numeric keys are taken to be literal conditions
 934          * Takes an array of selected variables, and a condition map, which is ANDed
 935          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 936          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 937          * $obj- >page_id is the ID of the Astronomy article
 938          * @param $fname String: Calling function name
 939          * @param $options Array
 940          * @param $join_conds Array
 941          *
 942          * @todo migrate documentation to phpdocumentor format
 943          */
 944         function selectRow( $table, $vars, $conds, $fname = 'DatabaseBase::selectRow', $options = array(), $join_conds = array() ) {
 945                 $options['LIMIT'] = 1;
 946                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
 947                 if ( $res === false )
 948                         return false;
 949                 if ( !$this->numRows($res) ) {
 950                         return false;
 951                 }
 952                 $obj = $this->fetchObject( $res );
 953                 return $obj;
 954         }
 955
 956         /**
 957          * Estimate rows in dataset
 958          * Returns estimated count - not necessarily an accurate estimate across different databases,
 959          * so use sparingly
 960          * Takes same arguments as DatabaseBase::select()
 961          *
 962          * @param $table String: table name
 963          * @param $vars Array: unused
 964          * @param $conds Array: filters on the table
 965          * @param $fname String: function name for profiling
 966          * @param $options Array: options for select
 967          * @return Integer: row count
 968          */
 969         public function estimateRowCount( $table, $vars='*', $conds='', $fname = 'DatabaseBase::estimateRowCount', $options = array() ) {
 970                 $rows = 0;
 971                 $res = $this->select ( $table, 'COUNT(*) AS rowcount', $conds, $fname, $options );
 972                 if ( $res ) {
 973                         $row = $this->fetchRow( $res );
 974                         $rows = ( isset( $row['rowcount'] ) ) ? $row['rowcount'] : 0;
 975                 }
 976                 return $rows;
 977         }
 978
 979         /**
 980          * Removes most variables from an SQL query and replaces them with X or N for numbers.
 981          * It's only slightly flawed. Don't use for anything important.
 982          *
 983          * @param $sql String: A SQL Query
 984          */
 985         static function generalizeSQL( $sql ) {
 986                 # This does the same as the regexp below would do, but in such a way
 987                 # as to avoid crashing php on some large strings.
 988                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
 989
 990                 $sql = str_replace ( "\\\\", '', $sql);
 991                 $sql = str_replace ( "\\'", '', $sql);
 992                 $sql = str_replace ( "\\\"", '', $sql);
 993                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
 994                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
 995
 996                 # All newlines, tabs, etc replaced by single space
 997                 $sql = preg_replace ( '/\s+/', ' ', $sql);
 998
 999                 # All numbers => N
1000                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1001
1002                 return $sql;
1003         }
1004
1005         /**
1006          * Determines whether a field exists in a table
1007          *
1008          * @param $table String: table name
1009          * @param $field String: filed to check on that table
1010          * @param $fname String: calling function name (optional)
1011          * @return Boolean: whether $table has filed $field
1012          */
1013         function fieldExists( $table, $field, $fname = 'DatabaseBase::fieldExists' ) {
1014                 $info = $this->fieldInfo( $table, $field );
1015                 return (bool)$info;
1016         }
1017
1018         /**
1019          * Determines whether an index exists
1020          * Usually aborts on failure
1021          * If errors are explicitly ignored, returns NULL on failure
1022          */
1023         function indexExists( $table, $index, $fname = 'DatabaseBase::indexExists' ) {
1024                 $info = $this->indexInfo( $table, $index, $fname );
1025                 if ( is_null( $info ) ) {
1026                         return null;
1027                 } else {
1028                         return $info !== false;
1029                 }
1030         }
1031
1032
1033         /**
1034          * Get information about an index into an object
1035          * Returns false if the index does not exist
1036          */
1037         function indexInfo( $table, $index, $fname = 'DatabaseBase::indexInfo' ) {
1038                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1039                 # SHOW INDEX should work for 3.x and up:
1040                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1041                 $table = $this->tableName( $table );
1042                 $index = $this->indexName( $index );
1043                 $sql = 'SHOW INDEX FROM '.$table;
1044                 $res = $this->query( $sql, $fname );
1045                 if ( !$res ) {
1046                         return null;
1047                 }
1048
1049                 $result = array();
1050                 while ( $row = $this->fetchObject( $res ) ) {
1051                         if ( $row->Key_name == $index ) {
1052                                 $result[] = $row;
1053                         }
1054                 }
1055
1056                 return empty($result) ? false : $result;
1057         }
1058
1059         /**
1060          * Query whether a given table exists
1061          */
1062         function tableExists( $table ) {
1063                 $table = $this->tableName( $table );
1064                 $old = $this->ignoreErrors( true );
1065                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1066                 $this->ignoreErrors( $old );
1067                 return (bool)$res;
1068         }
1069
1070         /**
1071          * mysql_fetch_field() wrapper
1072          * Returns false if the field doesn't exist
1073          *
1074          * @param $table
1075          * @param $field
1076          */
1077         abstract function fieldInfo( $table, $field );
1078
1079         /**
1080          * mysql_field_type() wrapper
1081          */
1082         function fieldType( $res, $index ) {
1083                 if ( $res instanceof ResultWrapper ) {
1084                         $res = $res->result;
1085                 }
1086                 return mysql_field_type( $res, $index );
1087         }
1088
1089         /**
1090          * Determines if a given index is unique
1091          */
1092         function indexUnique( $table, $index ) {
1093                 $indexInfo = $this->indexInfo( $table, $index );
1094                 if ( !$indexInfo ) {
1095                         return null;
1096                 }
1097                 return !$indexInfo[0]->Non_unique;
1098         }
1099
1100         /**
1101          * INSERT wrapper, inserts an array into a table
1102          *
1103          * $a may be a single associative array, or an array of these with numeric keys, for
1104          * multi-row insert.
1105          *
1106          * Usually aborts on failure
1107          * If errors are explicitly ignored, returns success
1108          *
1109          * @param $table   String: table name (prefix auto-added)
1110          * @param $a       Array: Array of rows to insert
1111          * @param $fname   String: Calling function name (use __METHOD__) for logs/profiling
1112          * @param $options Mixed: Associative array of options
1113          *
1114          * @return bool
1115          */
1116         function insert( $table, $a, $fname = 'DatabaseBase::insert', $options = array() ) {
1117                 # No rows to insert, easy just return now
1118                 if ( !count( $a ) ) {
1119                         return true;
1120                 }
1121
1122                 $table = $this->tableName( $table );
1123                 if ( !is_array( $options ) ) {
1124                         $options = array( $options );
1125                 }
1126                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1127                         $multi = true;
1128                         $keys = array_keys( $a[0] );
1129                 } else {
1130                         $multi = false;
1131                         $keys = array_keys( $a );
1132                 }
1133
1134                 $sql = 'INSERT ' . implode( ' ', $options ) .
1135                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1136
1137                 if ( $multi ) {
1138                         $first = true;
1139                         foreach ( $a as $row ) {
1140                                 if ( $first ) {
1141                                         $first = false;
1142                                 } else {
1143                                         $sql .= ',';
1144                                 }
1145                                 $sql .= '(' . $this->makeList( $row ) . ')';
1146                         }
1147                 } else {
1148                         $sql .= '(' . $this->makeList( $a ) . ')';
1149                 }
1150
1151                 return (bool)$this->query( $sql, $fname );
1152         }
1153
1154         /**
1155          * INSERT ... ON DUPE UPDATE wrapper, inserts an array into a table, optionally updating if
1156          * duplicate primary key found
1157          *
1158          * $a may be a single associative array, or an array of these with numeric keys, for
1159          * multi-row insert.
1160          *
1161          * Usually aborts on failure
1162          * If errors are explicitly ignored, returns success
1163          *
1164          * @param $table   String: table name (prefix auto-added)
1165          * @param $a       Array: Array of rows to insert
1166          * @param $fname   String: Calling function name (use __METHOD__) for logs/profiling
1167          * @param $options Mixed: Associative array of options (ignored)
1168          * @param $onDupeUpdate   Array: Associative array of fields to update on duplicate
1169          *
1170          * @return bool
1171          */
1172         function insertOrUpdate( $table, $a, $fname = 'DatabaseBase::insertOnDupeUpdate', $options = array(), $onDupeUpdate = array() ) {
1173
1174                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1175                         $keys = array_keys( $a[0] );
1176                 } else {
1177                         $keys = array_keys( $a );
1178                 }
1179
1180                 //Get what is only to be set if inserted
1181                 $where = array_diff( $a, $onDupeUpdate );
1182
1183                 $res = $this->select(
1184                         $table,
1185                         $keys,
1186                         $this->makeList( $where, LIST_AND ),
1187                         __METHOD__
1188                 );
1189
1190                 if ( $res ) {
1191                         //Where there is a different value to set if this is being "updated", use the $onDupeUpdate value for that to
1192                         //replace the original option (if it was an insert), and replace the column name with the value read from
1193                         //the existing row
1194                         foreach( $where as $k => $v ){
1195                                 if ( isset( $onDupeUpdate[$k] ) ){
1196                                         $options[$k] = str_replace( $k, $res[0]->{$k}, $onDupeUpdate[$k] );
1197                                 }
1198                         }
1199                 } else {
1200                         //No results, it's just an insert
1201                         $update = $where;
1202                 }
1203
1204                 return (bool)$this->replace(
1205                         $table,
1206                         $update,
1207                         array(),
1208                         __METHOD__
1209                 );
1210         }
1211
1212         /**
1213          * Make UPDATE options for the DatabaseBase::update function
1214          *
1215          * @private
1216          * @param $options Array: The options passed to DatabaseBase::update
1217          * @return string
1218          */
1219         function makeUpdateOptions( $options ) {
1220                 if( !is_array( $options ) ) {
1221                         $options = array( $options );
1222                 }
1223                 $opts = array();
1224                 if ( in_array( 'LOW_PRIORITY', $options ) ) {
1225                         $opts[] = $this->lowPriorityOption();
1226                 }
1227                 if ( in_array( 'IGNORE', $options ) ) {
1228                         $opts[] = 'IGNORE';
1229                 }
1230                 return implode(' ', $opts);
1231         }
1232
1233         /**
1234          * UPDATE wrapper, takes a condition array and a SET array
1235          *
1236          * @param $table  String: The table to UPDATE
1237          * @param $values Array:  An array of values to SET
1238          * @param $conds  Array:  An array of conditions (WHERE). Use '*' to update all rows.
1239          * @param $fname  String: The Class::Function calling this function
1240          *                        (for the log)
1241          * @param $options Array: An array of UPDATE options, can be one or
1242          *                        more of IGNORE, LOW_PRIORITY
1243          * @return Boolean
1244          */
1245         function update( $table, $values, $conds, $fname = 'DatabaseBase::update', $options = array() ) {
1246                 $table = $this->tableName( $table );
1247                 $opts = $this->makeUpdateOptions( $options );
1248                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1249                 if ( $conds != '*' ) {
1250                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1251                 }
1252                 return $this->query( $sql, $fname );
1253         }
1254
1255         /**
1256          * Makes an encoded list of strings from an array
1257          * $mode:
1258          *        LIST_COMMA         - comma separated, no field names
1259          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1260          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1261          *        LIST_SET           - comma separated with field names, like a SET clause
1262          *        LIST_NAMES         - comma separated field names
1263          */
1264         function makeList( $a, $mode = LIST_COMMA ) {
1265                 if ( !is_array( $a ) ) {
1266                         throw new DBUnexpectedError( $this, 'DatabaseBase::makeList called with incorrect parameters' );
1267                 }
1268
1269                 $first = true;
1270                 $list = '';
1271                 foreach ( $a as $field => $value ) {
1272                         if ( !$first ) {
1273                                 if ( $mode == LIST_AND ) {
1274                                         $list .= ' AND ';
1275                                 } elseif($mode == LIST_OR) {
1276                                         $list .= ' OR ';
1277                                 } else {
1278                                         $list .= ',';
1279                                 }
1280                         } else {
1281                                 $first = false;
1282                         }
1283                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1284                                 $list .= "($value)";
1285                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1286                                 $list .= "$value";
1287                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1288                                 if( count( $value ) == 0 ) {
1289                                         throw new MWException( __METHOD__.': empty input' );
1290                                 } elseif( count( $value ) == 1 ) {
1291                                         // Special-case single values, as IN isn't terribly efficient
1292                                         // Don't necessarily assume the single key is 0; we don't
1293                                         // enforce linear numeric ordering on other arrays here.
1294                                         $value = array_values( $value );
1295                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1296                                 } else {
1297                                         $list .= $field." IN (".$this->makeList($value).") ";
1298                                 }
1299                         } elseif( $value === null ) {
1300                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1301                                         $list .= "$field IS ";
1302                                 } elseif ( $mode == LIST_SET ) {
1303                                         $list .= "$field = ";
1304                                 }
1305                                 $list .= 'NULL';
1306                         } else {
1307                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1308                                         $list .= "$field = ";
1309                                 }
1310                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1311                         }
1312                 }
1313                 return $list;
1314         }
1315
1316         /**
1317          * Build a partial where clause from a 2-d array such as used for LinkBatch.
1318          * The keys on each level may be either integers or strings.
1319          *
1320          * @param $data Array: organized as 2-d array(baseKeyVal => array(subKeyVal => <ignored>, ...), ...)
1321          * @param $baseKey String: field name to match the base-level keys to (eg 'pl_namespace')
1322          * @param $subKey String: field name to match the sub-level keys to (eg 'pl_title')
1323          * @return Mixed: string SQL fragment, or false if no items in array.
1324          */
1325         function makeWhereFrom2d( $data, $baseKey, $subKey ) {
1326                 $conds = array();
1327                 foreach ( $data as $base => $sub ) {
1328                         if ( count( $sub ) ) {
1329                                 $conds[] = $this->makeList(
1330                                         array( $baseKey => $base, $subKey => array_keys( $sub ) ),
1331                                         LIST_AND);
1332                         }
1333                 }
1334
1335                 if ( $conds ) {
1336                         return $this->makeList( $conds, LIST_OR );
1337                 } else {
1338                         // Nothing to search for...
1339                         return false;
1340                 }
1341         }
1342
1343         /**
1344          * Bitwise operations
1345          */
1346
1347         function bitNot($field) {
1348                 return "(~$field)";
1349         }
1350
1351         function bitAnd($fieldLeft, $fieldRight) {
1352                 return "($fieldLeft & $fieldRight)";
1353         }
1354
1355         function bitOr($fieldLeft, $fieldRight) {
1356                 return "($fieldLeft | $fieldRight)";
1357         }
1358
1359         /**
1360          * Change the current database
1361          *
1362          * @return bool Success or failure
1363          */
1364         function selectDB( $db ) {
1365                 # Stub.  Shouldn't cause serious problems if it's not overridden, but
1366                 # if your database engine supports a concept similar to MySQL's
1367                 # databases you may as well.  TODO: explain what exactly will fail if
1368                 # this is not overridden.
1369                 return true;
1370         }
1371
1372         /**
1373          * Get the current DB name
1374          */
1375         function getDBname() {
1376                 return $this->mDBname;
1377         }
1378
1379         /**
1380          * Get the server hostname or IP address
1381          */
1382         function getServer() {
1383                 return $this->mServer;
1384         }
1385
1386         /**
1387          * Format a table name ready for use in constructing an SQL query
1388          *
1389          * This does two important things: it quotes the table names to clean them up,
1390          * and it adds a table prefix if only given a table name with no quotes.
1391          *
1392          * All functions of this object which require a table name call this function
1393          * themselves. Pass the canonical name to such functions. This is only needed
1394          * when calling query() directly.
1395          *
1396          * @param $name String: database table name
1397          * @return String: full database name
1398          */
1399         function tableName( $name ) {
1400                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1401                 # Skip the entire process when we have a string quoted on both ends.
1402                 # Note that we check the end so that we will still quote any use of
1403                 # use of `database`.table. But won't break things if someone wants
1404                 # to query a database table with a dot in the name.
1405                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) {
1406                         return $name;
1407                 }
1408
1409                 # Lets test for any bits of text that should never show up in a table
1410                 # name. Basically anything like JOIN or ON which are actually part of
1411                 # SQL queries, but may end up inside of the table value to combine
1412                 # sql. Such as how the API is doing.
1413                 # Note that we use a whitespace test rather than a \b test to avoid
1414                 # any remote case where a word like on may be inside of a table name
1415                 # surrounded by symbols which may be considered word breaks.
1416                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
1417                         return $name;
1418                 }
1419
1420                 # Split database and table into proper variables.
1421                 # We reverse the explode so that database.table and table both output
1422                 # the correct table.
1423                 $dbDetails = array_reverse( explode( '.', $name, 2 ) );
1424                 if( isset( $dbDetails[1] ) ) {
1425                         @list( $table, $database ) = $dbDetails;
1426                 } else {
1427                         @list( $table ) = $dbDetails;
1428                 }
1429                 $prefix = $this->mTablePrefix; # Default prefix
1430
1431                 # A database name has been specified in input. Quote the table name
1432                 # because we don't want any prefixes added.
1433                 if( isset($database) ) {
1434                         $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1435                 }
1436
1437                 # Note that we use the long format because php will complain in in_array if
1438                 # the input is not an array, and will complain in is_array if it is not set.
1439                 if( !isset( $database ) # Don't use shared database if pre selected.
1440                  && isset( $wgSharedDB ) # We have a shared database
1441                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1442                  && isset( $wgSharedTables )
1443                  && is_array( $wgSharedTables )
1444                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1445                         $database = $wgSharedDB;
1446                         $prefix   = isset( $wgSharedPrefix ) ? $wgSharedPrefix : $prefix;
1447                 }
1448
1449                 # Quote the $database and $table and apply the prefix if not quoted.
1450                 if( isset($database) ) {
1451                         $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1452                 }
1453                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1454
1455                 # Merge our database and table into our final table name.
1456                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1457
1458                 # We're finished, return.
1459                 return $tableName;
1460         }
1461
1462         /**
1463          * Fetch a number of table names into an array
1464          * This is handy when you need to construct SQL for joins
1465          *
1466          * Example:
1467          * extract($dbr->tableNames('user','watchlist'));
1468          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1469          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1470          */
1471         public function tableNames() {
1472                 $inArray = func_get_args();
1473                 $retVal = array();
1474                 foreach ( $inArray as $name ) {
1475                         $retVal[$name] = $this->tableName( $name );
1476                 }
1477                 return $retVal;
1478         }
1479
1480         /**
1481          * Fetch a number of table names into an zero-indexed numerical array
1482          * This is handy when you need to construct SQL for joins
1483          *
1484          * Example:
1485          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1486          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1487          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1488          */
1489         public function tableNamesN() {
1490                 $inArray = func_get_args();
1491                 $retVal = array();
1492                 foreach ( $inArray as $name ) {
1493                         $retVal[] = $this->tableName( $name );
1494                 }
1495                 return $retVal;
1496         }
1497
1498         /**
1499          * @private
1500          */
1501         function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1502                 $ret = array();
1503                 $retJOIN = array();
1504                 $use_index_safe = is_array($use_index) ? $use_index : array();
1505                 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1506                 foreach ( $tables as $table ) {
1507                         // Is there a JOIN and INDEX clause for this table?
1508                         if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1509                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1510                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1511                                 $on = $this->makeList((array)$join_conds_safe[$table][1], LIST_AND);
1512                                 if ( $on != '' ) {
1513                                         $tableClause .= ' ON (' . $on . ')';
1514                                 }
1515                                 $retJOIN[] = $tableClause;
1516                         // Is there an INDEX clause?
1517                         } else if ( isset($use_index_safe[$table]) ) {
1518                                 $tableClause = $this->tableName( $table );
1519                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1520                                 $ret[] = $tableClause;
1521                         // Is there a JOIN clause?
1522                         } else if ( isset($join_conds_safe[$table]) ) {
1523                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1524                                 $on = $this->makeList((array)$join_conds_safe[$table][1], LIST_AND);
1525                                 if ( $on != '' ) {
1526                                         $tableClause .= ' ON (' . $on . ')';
1527                                 }
1528                                 $retJOIN[] = $tableClause;
1529                         } else {
1530                                 $tableClause = $this->tableName( $table );
1531                                 $ret[] = $tableClause;
1532                         }
1533                 }
1534                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1535                 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1536                 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1537                 // Compile our final table clause
1538                 return implode(' ',array($straightJoins,$otherJoins) );
1539         }
1540
1541         /**
1542          * Get the name of an index in a given table
1543          */
1544         function indexName( $index ) {
1545                 // Backwards-compatibility hack
1546                 $renamed = array(
1547                         'ar_usertext_timestamp' => 'usertext_timestamp',
1548                         'un_user_id'            => 'user_id',
1549                         'un_user_ip'            => 'user_ip',
1550                 );
1551                 if( isset( $renamed[$index] ) ) {
1552                         return $renamed[$index];
1553                 } else {
1554                         return $index;
1555                 }
1556         }
1557
1558         /**
1559          * Wrapper for addslashes()
1560          * @param $s String: to be slashed.
1561          * @return String: slashed string.
1562          */
1563         abstract function strencode( $s );
1564
1565         /**
1566          * If it's a string, adds quotes and backslashes
1567          * Otherwise returns as-is
1568          */
1569         function addQuotes( $s ) {
1570                 if ( $s === null ) {
1571                         return 'NULL';
1572                 } else {
1573                         # This will also quote numeric values. This should be harmless,
1574                         # and protects against weird problems that occur when they really
1575                         # _are_ strings such as article titles and string->number->string
1576                         # conversion is not 1:1.
1577                         return "'" . $this->strencode( $s ) . "'";
1578                 }
1579         }
1580
1581         /**
1582          * Escape string for safe LIKE usage.
1583          * WARNING: you should almost never use this function directly,
1584          * instead use buildLike() that escapes everything automatically
1585          * Deprecated in 1.17, warnings in 1.17, removed in ???
1586          */
1587         public function escapeLike( $s ) {
1588                 wfDeprecated( __METHOD__ );
1589                 return $this->escapeLikeInternal( $s );
1590         }
1591
1592         protected function escapeLikeInternal( $s ) {
1593                 $s = str_replace( '\\', '\\\\', $s );
1594                 $s = $this->strencode( $s );
1595                 $s = str_replace( array( '%', '_' ), array( '\%', '\_' ), $s );
1596                 return $s;
1597         }
1598
1599         /**
1600          * LIKE statement wrapper, receives a variable-length argument list with parts of pattern to match
1601          * containing either string literals that will be escaped or tokens returned by anyChar() or anyString().
1602          * Alternatively, the function could be provided with an array of aforementioned parameters.
1603          *
1604          * Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns a LIKE clause that searches
1605          * for subpages of 'My page title'.
1606          * Alternatively: $pattern = array( 'My_page_title/', $dbr->anyString() ); $query .= $dbr->buildLike( $pattern );
1607          *
1608          * @since 1.16
1609          * @return String: fully built LIKE statement
1610          */
1611         function buildLike() {
1612                 $params = func_get_args();
1613                 if (count($params) > 0 && is_array($params[0])) {
1614                         $params = $params[0];
1615                 }
1616
1617                 $s = '';
1618                 foreach( $params as $value) {
1619                         if( $value instanceof LikeMatch ) {
1620                                 $s .= $value->toString();
1621                         } else {
1622                                 $s .= $this->escapeLikeInternal( $value );
1623                         }
1624                 }
1625                 return " LIKE '" . $s . "' ";
1626         }
1627
1628         /**
1629          * Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
1630          */
1631         function anyChar() {
1632                 return new LikeMatch( '_' );
1633         }
1634
1635         /**
1636          * Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
1637          */
1638         function anyString() {
1639                 return new LikeMatch( '%' );
1640         }
1641
1642         /**
1643          * Returns an appropriately quoted sequence value for inserting a new row.
1644          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1645          * subclass will return an integer, and save the value for insertId()
1646          */
1647         function nextSequenceValue( $seqName ) {
1648                 return null;
1649         }
1650
1651         /**
1652          * USE INDEX clause.  Unlikely to be useful for anything but MySQL.  This
1653          * is only needed because a) MySQL must be as efficient as possible due to
1654          * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
1655          * which index to pick.  Anyway, other databases might have different
1656          * indexes on a given table.  So don't bother overriding this unless you're
1657          * MySQL.
1658          */
1659         function useIndexClause( $index ) {
1660                 return '';
1661         }
1662
1663         /**
1664          * REPLACE query wrapper
1665          * PostgreSQL simulates this with a DELETE followed by INSERT
1666          * $row is the row to insert, an associative array
1667          * $uniqueIndexes is an array of indexes. Each element may be either a
1668          * field name or an array of field names
1669          *
1670          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1671          * However if you do this, you run the risk of encountering errors which wouldn't have
1672          * occurred in MySQL
1673          *
1674          * @param $table String: The table to replace the row(s) in.
1675          * @param $uniqueIndexes Array: An associative array of indexes
1676          * @param $rows Array: Array of rows to replace
1677          * @param $fname String: Calling function name (use __METHOD__) for logs/profiling
1678          */
1679         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseBase::replace' ) {
1680                 $table = $this->tableName( $table );
1681
1682                 # Single row case
1683                 if ( !is_array( reset( $rows ) ) ) {
1684                         $rows = array( $rows );
1685                 }
1686
1687                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1688                 $first = true;
1689                 foreach ( $rows as $row ) {
1690                         if ( $first ) {
1691                                 $first = false;
1692                         } else {
1693                                 $sql .= ',';
1694                         }
1695                         $sql .= '(' . $this->makeList( $row ) . ')';
1696                 }
1697                 return $this->query( $sql, $fname );
1698         }
1699
1700         /**
1701          * DELETE where the condition is a join
1702          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1703          *
1704          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1705          * join condition matches, set $conds='*'
1706          *
1707          * DO NOT put the join condition in $conds
1708          *
1709          * @param $delTable String: The table to delete from.
1710          * @param $joinTable String: The other table.
1711          * @param $delVar String: The variable to join on, in the first table.
1712          * @param $joinVar String: The variable to join on, in the second table.
1713          * @param $conds Array: Condition array of field names mapped to variables, ANDed together in the WHERE clause
1714          * @param $fname String: Calling function name (use __METHOD__) for logs/profiling
1715          */
1716         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'DatabaseBase::deleteJoin' ) {
1717                 if ( !$conds ) {
1718                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
1719                 }
1720
1721                 $delTable = $this->tableName( $delTable );
1722                 $joinTable = $this->tableName( $joinTable );
1723                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1724                 if ( $conds != '*' ) {
1725                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1726                 }
1727
1728                 return $this->query( $sql, $fname );
1729         }
1730
1731         /**
1732          * Returns the size of a text field, or -1 for "unlimited"
1733          */
1734         function textFieldSize( $table, $field ) {
1735                 $table = $this->tableName( $table );
1736                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1737                 $res = $this->query( $sql, 'DatabaseBase::textFieldSize' );
1738                 $row = $this->fetchObject( $res );
1739
1740                 $m = array();
1741                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1742                         $size = $m[1];
1743                 } else {
1744                         $size = -1;
1745                 }
1746                 return $size;
1747         }
1748
1749         /**
1750          * A string to insert into queries to show that they're low-priority, like
1751          * MySQL's LOW_PRIORITY.  If no such feature exists, return an empty
1752          * string and nothing bad should happen.
1753          *
1754          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1755          */
1756         function lowPriorityOption() {
1757                 return '';
1758         }
1759
1760         /**
1761          * DELETE query wrapper
1762          *
1763          * Use $conds == "*" to delete all rows
1764          */
1765         function delete( $table, $conds, $fname = 'DatabaseBase::delete' ) {
1766                 if ( !$conds ) {
1767                         throw new DBUnexpectedError( $this, 'DatabaseBase::delete() called with no conditions' );
1768                 }
1769                 $table = $this->tableName( $table );
1770                 $sql = "DELETE FROM $table";
1771                 if ( $conds != '*' ) {
1772                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1773                 }
1774                 return $this->query( $sql, $fname );
1775         }
1776
1777         /**
1778          * INSERT SELECT wrapper
1779          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1780          * Source items may be literals rather than field names, but strings should be quoted with DatabaseBase::addQuotes()
1781          * $conds may be "*" to copy the whole table
1782          * srcTable may be an array of tables.
1783          */
1784         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabaseBase::insertSelect',
1785                 $insertOptions = array(), $selectOptions = array() )
1786         {
1787                 $destTable = $this->tableName( $destTable );
1788                 if ( is_array( $insertOptions ) ) {
1789                         $insertOptions = implode( ' ', $insertOptions );
1790                 }
1791                 if( !is_array( $selectOptions ) ) {
1792                         $selectOptions = array( $selectOptions );
1793                 }
1794                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1795                 if( is_array( $srcTable ) ) {
1796                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1797                 } else {
1798                         $srcTable = $this->tableName( $srcTable );
1799                 }
1800                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1801                         " SELECT $startOpts " . implode( ',', $varMap ) .
1802                         " FROM $srcTable $useIndex ";
1803                 if ( $conds != '*' ) {
1804                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1805                 }
1806                 $sql .= " $tailOpts";
1807                 return $this->query( $sql, $fname );
1808         }
1809
1810         /**
1811          * Construct a LIMIT query with optional offset.  This is used for query
1812          * pages.  The SQL should be adjusted so that only the first $limit rows
1813          * are returned.  If $offset is provided as well, then the first $offset
1814          * rows should be discarded, and the next $limit rows should be returned.
1815          * If the result of the query is not ordered, then the rows to be returned
1816          * are theoretically arbitrary.
1817          *
1818          * $sql is expected to be a SELECT, if that makes a difference.  For
1819          * UPDATE, limitResultForUpdate should be used.
1820          *
1821          * The version provided by default works in MySQL and SQLite.  It will very
1822          * likely need to be overridden for most other DBMSes.
1823          *
1824          * @param $sql String: SQL query we will append the limit too
1825          * @param $limit Integer: the SQL limit
1826          * @param $offset Integer the SQL offset (default false)
1827          */
1828         function limitResult( $sql, $limit, $offset=false ) {
1829                 if( !is_numeric( $limit ) ) {
1830                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1831                 }
1832                 return "$sql LIMIT "
1833                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1834                                 . "{$limit} ";
1835         }
1836         function limitResultForUpdate( $sql, $num ) {
1837                 return $this->limitResult( $sql, $num, 0 );
1838         }
1839
1840         /**
1841          * Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries
1842          * within the UNION construct.
1843          * @return Boolean
1844          */
1845         function unionSupportsOrderAndLimit() {
1846                 return true; // True for almost every DB supported
1847         }
1848
1849         /**
1850          * Construct a UNION query
1851          * This is used for providing overload point for other DB abstractions
1852          * not compatible with the MySQL syntax.
1853          * @param $sqls Array: SQL statements to combine
1854          * @param $all Boolean: use UNION ALL
1855          * @return String: SQL fragment
1856          */
1857         function unionQueries($sqls, $all) {
1858                 $glue = $all ? ') UNION ALL (' : ') UNION (';
1859                 return '('.implode( $glue, $sqls ) . ')';
1860         }
1861
1862         /**
1863          * Returns an SQL expression for a simple conditional.  This doesn't need
1864          * to be overridden unless CASE isn't supported in your DBMS.
1865          *
1866          * @param $cond String: SQL expression which will result in a boolean value
1867          * @param $trueVal String: SQL expression to return if true
1868          * @param $falseVal String: SQL expression to return if false
1869          * @return String: SQL fragment
1870          */
1871         function conditional( $cond, $trueVal, $falseVal ) {
1872                 return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
1873         }
1874
1875         /**
1876          * Returns a comand for str_replace function in SQL query.
1877          * Uses REPLACE() in MySQL
1878          *
1879          * @param $orig String: column to modify
1880          * @param $old String: column to seek
1881          * @param $new String: column to replace with
1882          */
1883         function strreplace( $orig, $old, $new ) {
1884                 return "REPLACE({$orig}, {$old}, {$new})";
1885         }
1886
1887         /**
1888          * Determines if the last failure was due to a deadlock
1889          * STUB
1890          */
1891         function wasDeadlock() {
1892                 return false;
1893         }
1894
1895         /**
1896          * Determines if the last query error was something that should be dealt
1897          * with by pinging the connection and reissuing the query.
1898          * STUB
1899          */
1900         function wasErrorReissuable() {
1901                 return false;
1902         }
1903
1904         /**
1905          * Determines if the last failure was due to the database being read-only.
1906          * STUB
1907          */
1908         function wasReadOnlyError() {
1909                 return false;
1910         }
1911
1912         /**
1913          * Perform a deadlock-prone transaction.
1914          *
1915          * This function invokes a callback function to perform a set of write
1916          * queries. If a deadlock occurs during the processing, the transaction
1917          * will be rolled back and the callback function will be called again.
1918          *
1919          * Usage:
1920          *   $dbw->deadlockLoop( callback, ... );
1921          *
1922          * Extra arguments are passed through to the specified callback function.
1923          *
1924          * Returns whatever the callback function returned on its successful,
1925          * iteration, or false on error, for example if the retry limit was
1926          * reached.
1927          */
1928         function deadlockLoop() {
1929                 $myFname = 'DatabaseBase::deadlockLoop';
1930
1931                 $this->begin();
1932                 $args = func_get_args();
1933                 $function = array_shift( $args );
1934                 $oldIgnore = $this->ignoreErrors( true );
1935                 $tries = DEADLOCK_TRIES;
1936                 if ( is_array( $function ) ) {
1937                         $fname = $function[0];
1938                 } else {
1939                         $fname = $function;
1940                 }
1941                 do {
1942                         $retVal = call_user_func_array( $function, $args );
1943                         $error = $this->lastError();
1944                         $errno = $this->lastErrno();
1945                         $sql = $this->lastQuery();
1946
1947                         if ( $errno ) {
1948                                 if ( $this->wasDeadlock() ) {
1949                                         # Retry
1950                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1951                                 } else {
1952                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1953                                 }
1954                         }
1955                 } while( $this->wasDeadlock() && --$tries > 0 );
1956                 $this->ignoreErrors( $oldIgnore );
1957                 if ( $tries <= 0 ) {
1958                         $this->rollback( $myFname );
1959                         $this->reportQueryError( $error, $errno, $sql, $fname );
1960                         return false;
1961                 } else {
1962                         $this->commit( $myFname );
1963                         return $retVal;
1964                 }
1965         }
1966
1967         /**
1968          * Do a SELECT MASTER_POS_WAIT()
1969          *
1970          * @param $pos MySQLMasterPos object
1971          * @param $timeout Integer: the maximum number of seconds to wait for synchronisation
1972          */
1973         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1974                 $fname = 'DatabaseBase::masterPosWait';
1975                 wfProfileIn( $fname );
1976
1977                 # Commit any open transactions
1978                 if ( $this->mTrxLevel ) {
1979                         $this->commit();
1980                 }
1981
1982                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1983                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1984                         if ( $wait > $timeout * 1e6 ) {
1985                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1986                                 wfProfileOut( $fname );
1987                                 return -1;
1988                         } elseif ( $wait > 0 ) {
1989                                 wfDebug( "Fake slave waiting $wait us\n" );
1990                                 usleep( $wait );
1991                                 wfProfileOut( $fname );
1992                                 return 1;
1993                         } else {
1994                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1995                                 wfProfileOut( $fname );
1996                                 return 0;
1997                         }
1998                 }
1999
2000                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
2001                 $encFile = $this->addQuotes( $pos->file );
2002                 $encPos = intval( $pos->pos );
2003                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
2004                 $res = $this->doQuery( $sql );
2005                 if ( $res && $row = $this->fetchRow( $res ) ) {
2006                         wfProfileOut( $fname );
2007                         return $row[0];
2008                 } else {
2009                         wfProfileOut( $fname );
2010                         return false;
2011                 }
2012         }
2013
2014         /**
2015          * Get the position of the master from SHOW SLAVE STATUS
2016          */
2017         function getSlavePos() {
2018                 if ( !is_null( $this->mFakeSlaveLag ) ) {
2019                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
2020                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
2021                         return $pos;
2022                 }
2023                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
2024                 $row = $this->fetchObject( $res );
2025                 if ( $row ) {
2026                         $pos = isset($row->Exec_master_log_pos) ? $row->Exec_master_log_pos : $row->Exec_Master_Log_Pos;
2027                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
2028                 } else {
2029                         return false;
2030                 }
2031         }
2032
2033         /**
2034          * Get the position of the master from SHOW MASTER STATUS
2035          */
2036         function getMasterPos() {
2037                 if ( $this->mFakeMaster ) {
2038                         return new MySQLMasterPos( 'fake', microtime( true ) );
2039                 }
2040                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
2041                 $row = $this->fetchObject( $res );
2042                 if ( $row ) {
2043                         return new MySQLMasterPos( $row->File, $row->Position );
2044                 } else {
2045                         return false;
2046                 }
2047         }
2048
2049         /**
2050          * Begin a transaction, committing any previously open transaction
2051          */
2052         function begin( $fname = 'DatabaseBase::begin' ) {
2053                 $this->query( 'BEGIN', $fname );
2054                 $this->mTrxLevel = 1;
2055         }
2056
2057         /**
2058          * End a transaction
2059          */
2060         function commit( $fname = 'DatabaseBase::commit' ) {
2061                 if( $this->mTrxLevel ) {
2062                         $this->query( 'COMMIT', $fname );
2063                         $this->mTrxLevel = 0;
2064                 }
2065         }
2066
2067         /**
2068          * Rollback a transaction.
2069          * No-op on non-transactional databases.
2070          */
2071         function rollback( $fname = 'DatabaseBase::rollback' ) {
2072                 if( $this->mTrxLevel ) {
2073                         $this->query( 'ROLLBACK', $fname, true );
2074                         $this->mTrxLevel = 0;
2075                 }
2076         }
2077
2078         /**
2079          * Begin a transaction, committing any previously open transaction
2080          * @deprecated use begin()
2081          */
2082         function immediateBegin( $fname = 'DatabaseBase::immediateBegin' ) {
2083                 wfDeprecated( __METHOD__ );
2084                 $this->begin();
2085         }
2086
2087         /**
2088          * Commit transaction, if one is open
2089          * @deprecated use commit()
2090          */
2091         function immediateCommit( $fname = 'DatabaseBase::immediateCommit' ) {
2092                 wfDeprecated( __METHOD__ );
2093                 $this->commit();
2094         }
2095
2096         /**
2097          * Creates a new table with structure copied from existing table
2098          * Note that unlike most database abstraction functions, this function does not
2099          * automatically append database prefix, because it works at a lower
2100          * abstraction level.
2101          *
2102          * @param $oldName String: name of table whose structure should be copied
2103          * @param $newName String: name of table to be created
2104          * @param $temporary Boolean: whether the new table should be temporary
2105          * @param $fname String: calling function name
2106          * @return Boolean: true if operation was successful
2107          */
2108         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabaseBase::duplicateTableStructure' ) {
2109                 throw new MWException( 'DatabaseBase::duplicateTableStructure is not implemented in descendant class' );
2110         }
2111
2112         /**
2113          * Return MW-style timestamp used for MySQL schema
2114          */
2115         function timestamp( $ts=0 ) {
2116                 return wfTimestamp(TS_MW,$ts);
2117         }
2118
2119         /**
2120          * Local database timestamp format or null
2121          */
2122         function timestampOrNull( $ts = null ) {
2123                 if( is_null( $ts ) ) {
2124                         return null;
2125                 } else {
2126                         return $this->timestamp( $ts );
2127                 }
2128         }
2129
2130         /**
2131          * @todo document
2132          */
2133         function resultObject( $result ) {
2134                 if( empty( $result ) ) {
2135                         return false;
2136                 } elseif ( $result instanceof ResultWrapper ) {
2137                         return $result;
2138                 } elseif ( $result === true ) {
2139                         // Successful write query
2140                         return $result;
2141                 } else {
2142                         return new ResultWrapper( $this, $result );
2143                 }
2144         }
2145
2146         /**
2147          * Return aggregated value alias
2148          */
2149         function aggregateValue ($valuedata,$valuename='value') {
2150                 return $valuename;
2151         }
2152
2153         /**
2154          * Returns a wikitext link to the DB's website, e.g.,
2155          *     return "[http://www.mysql.com/ MySQL]";
2156          * Should at least contain plain text, if for some reason
2157          * your database has no website.
2158          *
2159          * @return String: wikitext of a link to the server software's web site
2160          */
2161         public static function getSoftwareLink() {
2162                 throw new MWException( "A child class of DatabaseBase didn't implement getSoftwareLink(), shame on them" );
2163         }
2164
2165         /**
2166          * A string describing the current software version, like from
2167          * mysql_get_server_info().  Will be listed on Special:Version, etc.
2168          *
2169          * @return String: Version information from the database
2170          */
2171         abstract function getServerVersion();
2172
2173         /**
2174          * Ping the server and try to reconnect if it there is no connection
2175          *
2176          * @return bool Success or failure
2177          */
2178         function ping() {
2179                 # Stub.  Not essential to override.
2180                 return true;
2181         }
2182
2183         /**
2184          * Get slave lag.
2185          * Currently supported only by MySQL
2186          * @return Database replication lag in seconds
2187          */
2188         function getLag() {
2189                 return $this->mFakeSlaveLag;
2190         }
2191
2192         /**
2193          * Get status information from SHOW STATUS in an associative array
2194          */
2195         function getStatus($which="%") {
2196                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2197                 $status = array();
2198                 while ( $row = $this->fetchObject( $res ) ) {
2199                         $status[$row->Variable_name] = $row->Value;
2200                 }
2201                 return $status;
2202         }
2203
2204         /**
2205          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2206          */
2207         function maxListLen() {
2208                 return 0;
2209         }
2210
2211         function encodeBlob($b) {
2212                 return $b;
2213         }
2214
2215         function decodeBlob($b) {
2216                 return $b;
2217         }
2218
2219         /**
2220          * Override database's default connection timeout.  May be useful for very
2221          * long batch queries such as full-wiki dumps, where a single query reads
2222          * out over hours or days.  May or may not be necessary for non-MySQL
2223          * databases.  For most purposes, leaving it as a no-op should be fine.
2224          *
2225          * @param $timeout Integer in seconds
2226          */
2227         public function setTimeout( $timeout ) {}
2228
2229         /**
2230          * Read and execute SQL commands from a file.
2231          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2232          * @param $filename String: File name to open
2233          * @param $lineCallback Callback: Optional function called before reading each line
2234          * @param $resultCallback Callback: Optional function called for each MySQL result
2235          */
2236         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2237                 $fp = fopen( $filename, 'r' );
2238                 if ( false === $fp ) {
2239                         if (!defined("MEDIAWIKI_INSTALL"))
2240                                 throw new MWException( "Could not open \"{$filename}\".\n" );
2241                         else
2242                                 return "Could not open \"{$filename}\".\n";
2243                 }
2244                 try {
2245                         $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2246                 }
2247                 catch( MWException $e ) {
2248                         if ( defined("MEDIAWIKI_INSTALL") ) {
2249                                 $error = $e->getMessage();
2250                         } else {
2251                                 fclose( $fp );
2252                                 throw $e;
2253                         }
2254                 }
2255
2256                 fclose( $fp );
2257                 return $error;
2258         }
2259
2260         /**
2261          * Get the full path of a patch file. Originally based on archive()
2262          * from updaters.inc. Keep in mind this always returns a patch, as
2263          * it fails back to MySQL if no DB-specific patch can be found
2264          *
2265          * @param $patch String The name of the patch, like patch-something.sql
2266          * @return String Full path to patch file
2267          */
2268         public static function patchPath( $patch ) {
2269                 global $wgDBtype, $IP;
2270                 if ( file_exists( "$IP/maintenance/$wgDBtype/archives/$patch" ) ) {
2271                         return "$IP/maintenance/$wgDBtype/archives/$patch";
2272                 } else {
2273                         return "$IP/maintenance/archives/$patch";
2274                 }
2275         }
2276
2277         /**
2278          * Read and execute commands from an open file handle
2279          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2280          * @param $fp String: File handle
2281          * @param $lineCallback Callback: Optional function called before reading each line
2282          * @param $resultCallback Callback: Optional function called for each MySQL result
2283          */
2284         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2285                 $cmd = "";
2286                 $done = false;
2287                 $dollarquote = false;
2288
2289                 while ( ! feof( $fp ) ) {
2290                         if ( $lineCallback ) {
2291                                 call_user_func( $lineCallback );
2292                         }
2293                         $line = trim( fgets( $fp, 1024 ) );
2294                         $sl = strlen( $line ) - 1;
2295
2296                         if ( $sl < 0 ) { continue; }
2297                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2298
2299                         ## Allow dollar quoting for function declarations
2300                         if (substr($line,0,4) == '$mw$') {
2301                                 if ($dollarquote) {
2302                                         $dollarquote = false;
2303                                         $done = true;
2304                                 }
2305                                 else {
2306                                         $dollarquote = true;
2307                                 }
2308                         }
2309                         else if (!$dollarquote) {
2310                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2311                                         $done = true;
2312                                         $line = substr( $line, 0, $sl );
2313                                 }
2314                         }
2315
2316                         if ( $cmd != '' ) { $cmd .= ' '; }
2317                         $cmd .= "$line\n";
2318
2319                         if ( $done ) {
2320                                 $cmd = str_replace(';;', ";", $cmd);
2321                                 $cmd = $this->replaceVars( $cmd );
2322                                 $res = $this->query( $cmd, __METHOD__ );
2323                                 if ( $resultCallback ) {
2324                                         call_user_func( $resultCallback, $res, $this );
2325                                 }
2326
2327                                 if ( false === $res ) {
2328                                         $err = $this->lastError();
2329                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2330                                 }
2331
2332                                 $cmd = '';
2333                                 $done = false;
2334                         }
2335                 }
2336                 return true;
2337         }
2338
2339
2340         /**
2341          * Replace variables in sourced SQL
2342          */
2343         protected function replaceVars( $ins ) {
2344                 $varnames = array(
2345                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2346                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2347                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2348                 );
2349
2350                 // Ordinary variables
2351                 foreach ( $varnames as $var ) {
2352                         if( isset( $GLOBALS[$var] ) ) {
2353                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2354                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2355                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2356                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2357                         }
2358                 }
2359
2360                 // Table prefixes
2361                 $ins = preg_replace_callback( '!/\*(?:\$wgDBprefix|_)\*/([a-zA-Z_0-9]*)!',
2362                         array( $this, 'tableNameCallback' ), $ins );
2363
2364                 // Index names
2365                 $ins = preg_replace_callback( '!/\*i\*/([a-zA-Z_0-9]*)!',
2366                         array( $this, 'indexNameCallback' ), $ins );
2367                 return $ins;
2368         }
2369
2370         /**
2371          * Table name callback
2372          * @private
2373          */
2374         protected function tableNameCallback( $matches ) {
2375                 return $this->tableName( $matches[1] );
2376         }
2377
2378         /**
2379          * Index name callback
2380          */
2381         protected function indexNameCallback( $matches ) {
2382                 return $this->indexName( $matches[1] );
2383         }
2384
2385         /**
2386          * Build a concatenation list to feed into a SQL query
2387          * @param $stringList Array: list of raw SQL expressions; caller is responsible for any quoting
2388          * @return String
2389          */
2390         function buildConcat( $stringList ) {
2391                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2392         }
2393
2394         /**
2395          * Acquire a named lock
2396          *
2397          * Abstracted from Filestore::lock() so child classes can implement for
2398          * their own needs.
2399          *
2400          * @param $lockName String: name of lock to aquire
2401          * @param $method String: name of method calling us
2402          * @param $timeout Integer: timeout
2403          * @return Boolean
2404          */
2405         public function lock( $lockName, $method, $timeout = 5 ) {
2406                 return true;
2407         }
2408
2409         /**
2410          * Release a lock.
2411          *
2412          * @param $lockName String: Name of lock to release
2413          * @param $method String: Name of method calling us
2414          *
2415          * @return Returns 1 if the lock was released, 0 if the lock was not established
2416          * by this thread (in which case the lock is not released), and NULL if the named
2417          * lock did not exist
2418          */
2419         public function unlock( $lockName, $method ) {
2420                 return true;
2421         }
2422
2423         /**
2424          * Lock specific tables
2425          *
2426          * @param $read Array of tables to lock for read access
2427          * @param $write Array of tables to lock for write access
2428          * @param $method String name of caller
2429          * @param $lowPriority bool Whether to indicate writes to be LOW PRIORITY
2430          */
2431         public function lockTables( $read, $write, $method, $lowPriority = true ) {
2432                 return true;
2433         }
2434
2435         /**
2436          * Unlock specific tables
2437          *
2438          * @param $method String the caller
2439          */
2440         public function unlockTables( $method ) {
2441                 return true;
2442         }
2443
2444         /**
2445          * Get search engine class. All subclasses of this need to implement this
2446          * if they wish to use searching.
2447          *
2448          * @return String
2449          */
2450         public function getSearchEngine() {
2451                 return 'SearchEngineDummy';
2452         }
2453
2454         /**
2455          * Allow or deny "big selects" for this session only. This is done by setting
2456          * the sql_big_selects session variable.
2457          *
2458          * This is a MySQL-specific feature.
2459          *
2460          * @param $value Mixed: true for allow, false for deny, or "default" to restore the initial value
2461          */
2462         public function setBigSelects( $value = true ) {
2463                 // no-op
2464         }
2465 }
2466
2467
2468 /******************************************************************************
2469  * Utility classes
2470  *****************************************************************************/
2471
2472 /**
2473  * Utility class.
2474  * @ingroup Database
2475  */
2476 class DBObject {
2477         public $mData;
2478
2479         function DBObject($data) {
2480                 $this->mData = $data;
2481         }
2482
2483         function isLOB() {
2484                 return false;
2485         }
2486
2487         function data() {
2488                 return $this->mData;
2489         }
2490 }
2491
2492 /**
2493  * Utility class
2494  * @ingroup Database
2495  *
2496  * This allows us to distinguish a blob from a normal string and an array of strings
2497  */
2498 class Blob {
2499         private $mData;
2500         function __construct($data) {
2501                 $this->mData = $data;
2502         }
2503         function fetch() {
2504                 return $this->mData;
2505         }
2506 }
2507
2508 /**
2509  * Utility class.
2510  * @ingroup Database
2511  */
2512 class MySQLField {
2513         private $name, $tablename, $default, $max_length, $nullable,
2514                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2515         function __construct ($info) {
2516                 $this->name = $info->name;
2517                 $this->tablename = $info->table;
2518                 $this->default = $info->def;
2519                 $this->max_length = $info->max_length;
2520                 $this->nullable = !$info->not_null;
2521                 $this->is_pk = $info->primary_key;
2522                 $this->is_unique = $info->unique_key;
2523                 $this->is_multiple = $info->multiple_key;
2524                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2525                 $this->type = $info->type;
2526         }
2527
2528         function name() {
2529                 return $this->name;
2530         }
2531
2532         function tableName() {
2533                 return $this->tableName;
2534         }
2535
2536         function defaultValue() {
2537                 return $this->default;
2538         }
2539
2540         function maxLength() {
2541                 return $this->max_length;
2542         }
2543
2544         function nullable() {
2545                 return $this->nullable;
2546         }
2547
2548         function isKey() {
2549                 return $this->is_key;
2550         }
2551
2552         function isMultipleKey() {
2553                 return $this->is_multiple;
2554         }
2555
2556         function type() {
2557                 return $this->type;
2558         }
2559 }
2560
2561 /******************************************************************************
2562  * Error classes
2563  *****************************************************************************/
2564
2565 /**
2566  * Database error base class
2567  * @ingroup Database
2568  */
2569 class DBError extends MWException {
2570         public $db;
2571
2572         /**
2573          * Construct a database error
2574          * @param $db Database object which threw the error
2575          * @param $error A simple error message to be used for debugging
2576          */
2577         function __construct( DatabaseBase &$db, $error ) {
2578                 $this->db =& $db;
2579                 parent::__construct( $error );
2580         }
2581
2582         function getText() {
2583                 global $wgShowDBErrorBacktrace;
2584                 $s = $this->getMessage() . "\n";
2585                 if ( $wgShowDBErrorBacktrace ) {
2586                         $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
2587                 }
2588                 return $s;
2589         }
2590 }
2591
2592 /**
2593  * @ingroup Database
2594  */
2595 class DBConnectionError extends DBError {
2596         public $error;
2597
2598         function __construct( DatabaseBase &$db, $error = 'unknown error' ) {
2599                 $msg = 'DB connection error';
2600                 if ( trim( $error ) != '' ) {
2601                         $msg .= ": $error";
2602                 }
2603                 $this->error = $error;
2604                 parent::__construct( $db, $msg );
2605         }
2606
2607         function useOutputPage() {
2608                 // Not likely to work
2609                 return false;
2610         }
2611
2612         function useMessageCache() {
2613                 // Not likely to work
2614                 return false;
2615         }
2616
2617         function getLogMessage() {
2618                 # Don't send to the exception log
2619                 return false;
2620         }
2621
2622         function getPageTitle() {
2623                 global $wgSitename, $wgLang;
2624                 $header = "$wgSitename has a problem";
2625                 if ( $wgLang instanceof Language ) {
2626                         $header = htmlspecialchars( $wgLang->getMessage( 'dberr-header' ) );
2627                 }
2628
2629                 return $header;
2630         }
2631
2632         function getHTML() {
2633                 global $wgLang, $wgMessageCache, $wgUseFileCache, $wgShowDBErrorBacktrace;
2634
2635                 $sorry = 'Sorry! This site is experiencing technical difficulties.';
2636                 $again = 'Try waiting a few minutes and reloading.';
2637                 $info  = '(Can\'t contact the database server: $1)';
2638
2639                 if ( $wgLang instanceof Language ) {
2640                         $sorry = htmlspecialchars( $wgLang->getMessage( 'dberr-problems' ) );
2641                         $again = htmlspecialchars( $wgLang->getMessage( 'dberr-again' ) );
2642                         $info  = htmlspecialchars( $wgLang->getMessage( 'dberr-info' ) );
2643                 }
2644
2645                 # No database access
2646                 if ( is_object( $wgMessageCache ) ) {
2647                         $wgMessageCache->disable();
2648                 }
2649
2650                 if ( trim( $this->error ) == '' ) {
2651                         $this->error = $this->db->getProperty('mServer');
2652                 }
2653
2654                 $noconnect = "<p><strong>$sorry</strong><br />$again</p><p><small>$info</small></p>";
2655                 $text = str_replace( '$1', $this->error, $noconnect );
2656
2657                 if ( $wgShowDBErrorBacktrace ) {
2658                         $text .= '<p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) );
2659                 }
2660
2661                 $extra = $this->searchForm();
2662
2663                 if( $wgUseFileCache ) {
2664                         try {
2665                                 $cache = $this->fileCachedPage();
2666                                 # Cached version on file system?
2667                                 if( $cache !== null ) {
2668                                         # Hack: extend the body for error messages
2669                                         $cache = str_replace( array('</html>','</body>'), '', $cache );
2670                                         # Add cache notice...
2671                                         $cachederror = "This is a cached copy of the requested page, and may not be up to date. ";
2672                                         # Localize it if possible...
2673                                         if( $wgLang instanceof Language ) {
2674                                                 $cachederror = htmlspecialchars( $wgLang->getMessage( 'dberr-cachederror' ) );
2675                                         }
2676                                         $warning = "<div style='color:red;font-size:150%;font-weight:bold;'>$cachederror</div>";
2677                                         # Output cached page with notices on bottom and re-close body
2678                                         return "{$cache}{$warning}<hr />$text<hr />$extra</body></html>";
2679                                 }
2680                         } catch( MWException $e ) {
2681                                 // Do nothing, just use the default page
2682                         }
2683                 }
2684                 # Headers needed here - output is just the error message
2685                 return $this->htmlHeader()."$text<hr />$extra".$this->htmlFooter();
2686         }
2687
2688         function searchForm() {
2689                 global $wgSitename, $wgServer, $wgLang, $wgInputEncoding;
2690                 $usegoogle = "You can try searching via Google in the meantime.";
2691                 $outofdate = "Note that their indexes of our content may be out of date.";
2692                 $googlesearch = "Search";
2693
2694                 if ( $wgLang instanceof Language ) {
2695                         $usegoogle = htmlspecialchars( $wgLang->getMessage( 'dberr-usegoogle' ) );
2696                         $outofdate = htmlspecialchars( $wgLang->getMessage( 'dberr-outofdate' ) );
2697                         $googlesearch  = htmlspecialchars( $wgLang->getMessage( 'searchbutton' ) );
2698                 }
2699
2700                 $search = htmlspecialchars(@$_REQUEST['search']);
2701
2702                 $trygoogle = <<<EOT
2703 <div style="margin: 1.5em">$usegoogle<br />
2704 <small>$outofdate</small></div>
2705 <!-- SiteSearch Google -->
2706 <form method="get" action="http://www.google.com/search" id="googlesearch">
2707     <input type="hidden" name="domains" value="$wgServer" />
2708     <input type="hidden" name="num" value="50" />
2709     <input type="hidden" name="ie" value="$wgInputEncoding" />
2710     <input type="hidden" name="oe" value="$wgInputEncoding" />
2711
2712     <input type="text" name="q" size="31" maxlength="255" value="$search" />
2713     <input type="submit" name="btnG" value="$googlesearch" />
2714   <div>
2715     <input type="radio" name="sitesearch" id="gwiki" value="$wgServer" checked="checked" /><label for="gwiki">$wgSitename</label>
2716     <input type="radio" name="sitesearch" id="gWWW" value="" /><label for="gWWW">WWW</label>
2717   </div>
2718 </form>
2719 <!-- SiteSearch Google -->
2720 EOT;
2721                 return $trygoogle;
2722         }
2723
2724         function fileCachedPage() {
2725                 global $wgTitle, $title, $wgLang, $wgOut;
2726                 if( $wgOut->isDisabled() ) return; // Done already?
2727                 $mainpage = 'Main Page';
2728                 if ( $wgLang instanceof Language ) {
2729                         $mainpage    = htmlspecialchars( $wgLang->getMessage( 'mainpage' ) );
2730                 }
2731
2732                 if( $wgTitle ) {
2733                         $t =& $wgTitle;
2734                 } elseif( $title ) {
2735                         $t = Title::newFromURL( $title );
2736                 } else {
2737                         $t = Title::newFromText( $mainpage );
2738                 }
2739
2740                 $cache = new HTMLFileCache( $t );
2741                 if( $cache->isFileCached() ) {
2742                         return $cache->fetchPageText();
2743                 } else {
2744                         return '';
2745                 }
2746         }
2747
2748         function htmlBodyOnly() {
2749                 return true;
2750         }
2751
2752 }
2753
2754 /**
2755  * @ingroup Database
2756  */
2757 class DBQueryError extends DBError {
2758         public $error, $errno, $sql, $fname;
2759
2760         function __construct( DatabaseBase &$db, $error, $errno, $sql, $fname ) {
2761                 $message = "A database error has occurred\n" .
2762                   "Query: $sql\n" .
2763                   "Function: $fname\n" .
2764                   "Error: $errno $error\n";
2765
2766                 parent::__construct( $db, $message );
2767                 $this->error = $error;
2768                 $this->errno = $errno;
2769                 $this->sql = $sql;
2770                 $this->fname = $fname;
2771         }
2772
2773         function getText() {
2774                 global $wgShowDBErrorBacktrace;
2775                 if ( $this->useMessageCache() ) {
2776                         $s = wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2777                                 htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2778                         if ( $wgShowDBErrorBacktrace ) {
2779                                 $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
2780                         }
2781                         return $s;
2782                 } else {
2783                         return parent::getText();
2784                 }
2785         }
2786
2787         function getSQL() {
2788                 global $wgShowSQLErrors;
2789                 if( !$wgShowSQLErrors ) {
2790                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2791                 } else {
2792                         return $this->sql;
2793                 }
2794         }
2795
2796         function getLogMessage() {
2797                 # Don't send to the exception log
2798                 return false;
2799         }
2800
2801         function getPageTitle() {
2802                 return $this->msg( 'databaseerror', 'Database error' );
2803         }
2804
2805         function getHTML() {
2806                 global $wgShowDBErrorBacktrace;
2807                 if ( $this->useMessageCache() ) {
2808                         $s = wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2809                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2810                 } else {
2811                         $s = nl2br( htmlspecialchars( $this->getMessage() ) );
2812                 }
2813                 if ( $wgShowDBErrorBacktrace ) {
2814                         $s .= '<p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) );
2815                 }
2816                 return $s;
2817         }
2818 }
2819
2820 /**
2821  * @ingroup Database
2822  */
2823 class DBUnexpectedError extends DBError {}
2824
2825
2826 /**
2827  * Result wrapper for grabbing data queried by someone else
2828  * @ingroup Database
2829  */
2830 class ResultWrapper implements Iterator {
2831         var $db, $result, $pos = 0, $currentRow = null;
2832
2833         /**
2834          * Create a new result object from a result resource and a Database object
2835          */
2836         function ResultWrapper( $database, $result ) {
2837                 $this->db = $database;
2838                 if ( $result instanceof ResultWrapper ) {
2839                         $this->result = $result->result;
2840                 } else {
2841                         $this->result = $result;
2842                 }
2843         }
2844
2845         /**
2846          * Get the number of rows in a result object
2847          */
2848         function numRows() {
2849                 return $this->db->numRows( $this );
2850         }
2851
2852         /**
2853          * Fetch the next row from the given result object, in object form.
2854          * Fields can be retrieved with $row->fieldname, with fields acting like
2855          * member variables.
2856          *
2857          * @return MySQL row object
2858          * @throws DBUnexpectedError Thrown if the database returns an error
2859          */
2860         function fetchObject() {
2861                 return $this->db->fetchObject( $this );
2862         }
2863
2864         /**
2865          * Fetch the next row from the given result object, in associative array
2866          * form.  Fields are retrieved with $row['fieldname'].
2867          *
2868          * @return MySQL row object
2869          * @throws DBUnexpectedError Thrown if the database returns an error
2870          */
2871         function fetchRow() {
2872                 return $this->db->fetchRow( $this );
2873         }
2874
2875         /**
2876          * Free a result object
2877          */
2878         function free() {
2879                 $this->db->freeResult( $this );
2880                 unset( $this->result );
2881                 unset( $this->db );
2882         }
2883
2884         /**
2885          * Change the position of the cursor in a result object
2886          * See mysql_data_seek()
2887          */
2888         function seek( $row ) {
2889                 $this->db->dataSeek( $this, $row );
2890         }
2891
2892         /*********************
2893          * Iterator functions
2894          * Note that using these in combination with the non-iterator functions
2895          * above may cause rows to be skipped or repeated.
2896          */
2897
2898         function rewind() {
2899                 if ($this->numRows()) {
2900                         $this->db->dataSeek($this, 0);
2901                 }
2902                 $this->pos = 0;
2903                 $this->currentRow = null;
2904         }
2905
2906         function current() {
2907                 if ( is_null( $this->currentRow ) ) {
2908                         $this->next();
2909                 }
2910                 return $this->currentRow;
2911         }
2912
2913         function key() {
2914                 return $this->pos;
2915         }
2916
2917         function next() {
2918                 $this->pos++;
2919                 $this->currentRow = $this->fetchObject();
2920                 return $this->currentRow;
2921         }
2922
2923         function valid() {
2924                 return $this->current() !== false;
2925         }
2926 }
2927
2928 /* Overloads the relevant methods of the real ResultsWrapper so it
2929  * doesn't go anywhere near an actual database.
2930  */
2931 class FakeResultWrapper extends ResultWrapper {
2932
2933         var $result     = array();
2934         var $db         = null; // And it's going to stay that way :D
2935         var $pos        = 0;
2936         var $currentRow = null;
2937
2938         function __construct( $array ){
2939                 $this->result = $array;
2940         }
2941
2942         function numRows() {
2943                 return count( $this->result );
2944         }
2945
2946         function fetchRow() {
2947                 $this->currentRow = $this->result[$this->pos++];
2948                 return $this->currentRow;
2949         }
2950
2951         function seek( $row ) {
2952                 $this->pos = $row;
2953         }
2954
2955         function free() {}
2956
2957         // Callers want to be able to access fields with $this->fieldName
2958         function fetchObject(){
2959                 $this->currentRow = $this->result[$this->pos++];
2960                 return (object)$this->currentRow;
2961         }
2962
2963         function rewind() {
2964                 $this->pos = 0;
2965                 $this->currentRow = null;
2966         }
2967 }
2968
2969 /**
2970  * Used by DatabaseBase::buildLike() to represent characters that have special meaning in SQL LIKE clauses
2971  * and thus need no escaping. Don't instantiate it manually, use DatabaseBase::anyChar() and anyString() instead.
2972  */
2973 class LikeMatch {
2974         private $str;
2975
2976         public function __construct( $s ) {
2977                 $this->str = $s;
2978         }
2979
2980         public function toString() {
2981                 return $this->str;
2982         }
2983 }