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
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(), $onDupeUpdate = array() ) {
1173                 //TODO:FIXME
1174                 //$this->select();
1175                 //$this->replace();
1176         }
1177
1178         /**
1179          * Make UPDATE options for the DatabaseBase::update function
1180          *
1181          * @private
1182          * @param $options Array: The options passed to DatabaseBase::update
1183          * @return string
1184          */
1185         function makeUpdateOptions( $options ) {
1186                 if( !is_array( $options ) ) {
1187                         $options = array( $options );
1188                 }
1189                 $opts = array();
1190                 if ( in_array( 'LOW_PRIORITY', $options ) ) {
1191                         $opts[] = $this->lowPriorityOption();
1192                 }
1193                 if ( in_array( 'IGNORE', $options ) ) {
1194                         $opts[] = 'IGNORE';
1195                 }
1196                 return implode(' ', $opts);
1197         }
1198
1199         /**
1200          * UPDATE wrapper, takes a condition array and a SET array
1201          *
1202          * @param $table  String: The table to UPDATE
1203          * @param $values Array:  An array of values to SET
1204          * @param $conds  Array:  An array of conditions (WHERE). Use '*' to update all rows.
1205          * @param $fname  String: The Class::Function calling this function
1206          *                        (for the log)
1207          * @param $options Array: An array of UPDATE options, can be one or
1208          *                        more of IGNORE, LOW_PRIORITY
1209          * @return Boolean
1210          */
1211         function update( $table, $values, $conds, $fname = 'DatabaseBase::update', $options = array() ) {
1212                 $table = $this->tableName( $table );
1213                 $opts = $this->makeUpdateOptions( $options );
1214                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1215                 if ( $conds != '*' ) {
1216                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1217                 }
1218                 return $this->query( $sql, $fname );
1219         }
1220
1221         /**
1222          * Makes an encoded list of strings from an array
1223          * $mode:
1224          *        LIST_COMMA         - comma separated, no field names
1225          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1226          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1227          *        LIST_SET           - comma separated with field names, like a SET clause
1228          *        LIST_NAMES         - comma separated field names
1229          */
1230         function makeList( $a, $mode = LIST_COMMA ) {
1231                 if ( !is_array( $a ) ) {
1232                         throw new DBUnexpectedError( $this, 'DatabaseBase::makeList called with incorrect parameters' );
1233                 }
1234
1235                 $first = true;
1236                 $list = '';
1237                 foreach ( $a as $field => $value ) {
1238                         if ( !$first ) {
1239                                 if ( $mode == LIST_AND ) {
1240                                         $list .= ' AND ';
1241                                 } elseif($mode == LIST_OR) {
1242                                         $list .= ' OR ';
1243                                 } else {
1244                                         $list .= ',';
1245                                 }
1246                         } else {
1247                                 $first = false;
1248                         }
1249                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1250                                 $list .= "($value)";
1251                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1252                                 $list .= "$value";
1253                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1254                                 if( count( $value ) == 0 ) {
1255                                         throw new MWException( __METHOD__.': empty input' );
1256                                 } elseif( count( $value ) == 1 ) {
1257                                         // Special-case single values, as IN isn't terribly efficient
1258                                         // Don't necessarily assume the single key is 0; we don't
1259                                         // enforce linear numeric ordering on other arrays here.
1260                                         $value = array_values( $value );
1261                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1262                                 } else {
1263                                         $list .= $field." IN (".$this->makeList($value).") ";
1264                                 }
1265                         } elseif( $value === null ) {
1266                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1267                                         $list .= "$field IS ";
1268                                 } elseif ( $mode == LIST_SET ) {
1269                                         $list .= "$field = ";
1270                                 }
1271                                 $list .= 'NULL';
1272                         } else {
1273                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1274                                         $list .= "$field = ";
1275                                 }
1276                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1277                         }
1278                 }
1279                 return $list;
1280         }
1281
1282         /**
1283          * Build a partial where clause from a 2-d array such as used for LinkBatch.
1284          * The keys on each level may be either integers or strings.
1285          *
1286          * @param $data Array: organized as 2-d array(baseKeyVal => array(subKeyVal => <ignored>, ...), ...)
1287          * @param $baseKey String: field name to match the base-level keys to (eg 'pl_namespace')
1288          * @param $subKey String: field name to match the sub-level keys to (eg 'pl_title')
1289          * @return Mixed: string SQL fragment, or false if no items in array.
1290          */
1291         function makeWhereFrom2d( $data, $baseKey, $subKey ) {
1292                 $conds = array();
1293                 foreach ( $data as $base => $sub ) {
1294                         if ( count( $sub ) ) {
1295                                 $conds[] = $this->makeList(
1296                                         array( $baseKey => $base, $subKey => array_keys( $sub ) ),
1297                                         LIST_AND);
1298                         }
1299                 }
1300
1301                 if ( $conds ) {
1302                         return $this->makeList( $conds, LIST_OR );
1303                 } else {
1304                         // Nothing to search for...
1305                         return false;
1306                 }
1307         }
1308
1309         /**
1310          * Bitwise operations
1311          */
1312
1313         function bitNot($field) {
1314                 return "(~$field)";
1315         }
1316
1317         function bitAnd($fieldLeft, $fieldRight) {
1318                 return "($fieldLeft & $fieldRight)";
1319         }
1320
1321         function bitOr($fieldLeft, $fieldRight) {
1322                 return "($fieldLeft | $fieldRight)";
1323         }
1324
1325         /**
1326          * Change the current database
1327          *
1328          * @return bool Success or failure
1329          */
1330         function selectDB( $db ) {
1331                 # Stub.  Shouldn't cause serious problems if it's not overridden, but
1332                 # if your database engine supports a concept similar to MySQL's
1333                 # databases you may as well.  TODO: explain what exactly will fail if
1334                 # this is not overridden.
1335                 return true;
1336         }
1337
1338         /**
1339          * Get the current DB name
1340          */
1341         function getDBname() {
1342                 return $this->mDBname;
1343         }
1344
1345         /**
1346          * Get the server hostname or IP address
1347          */
1348         function getServer() {
1349                 return $this->mServer;
1350         }
1351
1352         /**
1353          * Format a table name ready for use in constructing an SQL query
1354          *
1355          * This does two important things: it quotes the table names to clean them up,
1356          * and it adds a table prefix if only given a table name with no quotes.
1357          *
1358          * All functions of this object which require a table name call this function
1359          * themselves. Pass the canonical name to such functions. This is only needed
1360          * when calling query() directly.
1361          *
1362          * @param $name String: database table name
1363          * @return String: full database name
1364          */
1365         function tableName( $name ) {
1366                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1367                 # Skip the entire process when we have a string quoted on both ends.
1368                 # Note that we check the end so that we will still quote any use of
1369                 # use of `database`.table. But won't break things if someone wants
1370                 # to query a database table with a dot in the name.
1371                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) {
1372                         return $name;
1373                 }
1374
1375                 # Lets test for any bits of text that should never show up in a table
1376                 # name. Basically anything like JOIN or ON which are actually part of
1377                 # SQL queries, but may end up inside of the table value to combine
1378                 # sql. Such as how the API is doing.
1379                 # Note that we use a whitespace test rather than a \b test to avoid
1380                 # any remote case where a word like on may be inside of a table name
1381                 # surrounded by symbols which may be considered word breaks.
1382                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
1383                         return $name;
1384                 }
1385
1386                 # Split database and table into proper variables.
1387                 # We reverse the explode so that database.table and table both output
1388                 # the correct table.
1389                 $dbDetails = array_reverse( explode( '.', $name, 2 ) );
1390                 if( isset( $dbDetails[1] ) ) {
1391                         @list( $table, $database ) = $dbDetails;
1392                 } else {
1393                         @list( $table ) = $dbDetails;
1394                 }
1395                 $prefix = $this->mTablePrefix; # Default prefix
1396
1397                 # A database name has been specified in input. Quote the table name
1398                 # because we don't want any prefixes added.
1399                 if( isset($database) ) {
1400                         $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1401                 }
1402
1403                 # Note that we use the long format because php will complain in in_array if
1404                 # the input is not an array, and will complain in is_array if it is not set.
1405                 if( !isset( $database ) # Don't use shared database if pre selected.
1406                  && isset( $wgSharedDB ) # We have a shared database
1407                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1408                  && isset( $wgSharedTables )
1409                  && is_array( $wgSharedTables )
1410                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1411                         $database = $wgSharedDB;
1412                         $prefix   = isset( $wgSharedPrefix ) ? $wgSharedPrefix : $prefix;
1413                 }
1414
1415                 # Quote the $database and $table and apply the prefix if not quoted.
1416                 if( isset($database) ) {
1417                         $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1418                 }
1419                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1420
1421                 # Merge our database and table into our final table name.
1422                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1423
1424                 # We're finished, return.
1425                 return $tableName;
1426         }
1427
1428         /**
1429          * Fetch a number of table names into an array
1430          * This is handy when you need to construct SQL for joins
1431          *
1432          * Example:
1433          * extract($dbr->tableNames('user','watchlist'));
1434          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1435          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1436          */
1437         public function tableNames() {
1438                 $inArray = func_get_args();
1439                 $retVal = array();
1440                 foreach ( $inArray as $name ) {
1441                         $retVal[$name] = $this->tableName( $name );
1442                 }
1443                 return $retVal;
1444         }
1445
1446         /**
1447          * Fetch a number of table names into an zero-indexed numerical array
1448          * This is handy when you need to construct SQL for joins
1449          *
1450          * Example:
1451          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1452          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1453          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1454          */
1455         public function tableNamesN() {
1456                 $inArray = func_get_args();
1457                 $retVal = array();
1458                 foreach ( $inArray as $name ) {
1459                         $retVal[] = $this->tableName( $name );
1460                 }
1461                 return $retVal;
1462         }
1463
1464         /**
1465          * @private
1466          */
1467         function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1468                 $ret = array();
1469                 $retJOIN = array();
1470                 $use_index_safe = is_array($use_index) ? $use_index : array();
1471                 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1472                 foreach ( $tables as $table ) {
1473                         // Is there a JOIN and INDEX clause for this table?
1474                         if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1475                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1476                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1477                                 $on = $this->makeList((array)$join_conds_safe[$table][1], LIST_AND);
1478                                 if ( $on != '' ) {
1479                                         $tableClause .= ' ON (' . $on . ')';
1480                                 }
1481                                 $retJOIN[] = $tableClause;
1482                         // Is there an INDEX clause?
1483                         } else if ( isset($use_index_safe[$table]) ) {
1484                                 $tableClause = $this->tableName( $table );
1485                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1486                                 $ret[] = $tableClause;
1487                         // Is there a JOIN clause?
1488                         } else if ( isset($join_conds_safe[$table]) ) {
1489                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1490                                 $on = $this->makeList((array)$join_conds_safe[$table][1], LIST_AND);
1491                                 if ( $on != '' ) {
1492                                         $tableClause .= ' ON (' . $on . ')';
1493                                 }
1494                                 $retJOIN[] = $tableClause;
1495                         } else {
1496                                 $tableClause = $this->tableName( $table );
1497                                 $ret[] = $tableClause;
1498                         }
1499                 }
1500                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1501                 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1502                 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1503                 // Compile our final table clause
1504                 return implode(' ',array($straightJoins,$otherJoins) );
1505         }
1506
1507         /**
1508          * Get the name of an index in a given table
1509          */
1510         function indexName( $index ) {
1511                 // Backwards-compatibility hack
1512                 $renamed = array(
1513                         'ar_usertext_timestamp' => 'usertext_timestamp',
1514                         'un_user_id'            => 'user_id',
1515                         'un_user_ip'            => 'user_ip',
1516                 );
1517                 if( isset( $renamed[$index] ) ) {
1518                         return $renamed[$index];
1519                 } else {
1520                         return $index;
1521                 }
1522         }
1523
1524         /**
1525          * Wrapper for addslashes()
1526          * @param $s String: to be slashed.
1527          * @return String: slashed string.
1528          */
1529         abstract function strencode( $s );
1530
1531         /**
1532          * If it's a string, adds quotes and backslashes
1533          * Otherwise returns as-is
1534          */
1535         function addQuotes( $s ) {
1536                 if ( $s === null ) {
1537                         return 'NULL';
1538                 } else {
1539                         # This will also quote numeric values. This should be harmless,
1540                         # and protects against weird problems that occur when they really
1541                         # _are_ strings such as article titles and string->number->string
1542                         # conversion is not 1:1.
1543                         return "'" . $this->strencode( $s ) . "'";
1544                 }
1545         }
1546
1547         /**
1548          * Escape string for safe LIKE usage.
1549          * WARNING: you should almost never use this function directly,
1550          * instead use buildLike() that escapes everything automatically
1551          * Deprecated in 1.17, warnings in 1.17, removed in ???
1552          */
1553         public function escapeLike( $s ) {
1554                 wfDeprecated( __METHOD__ );
1555                 return $this->escapeLikeInternal( $s );
1556         }
1557
1558         protected function escapeLikeInternal( $s ) {
1559                 $s = str_replace( '\\', '\\\\', $s );
1560                 $s = $this->strencode( $s );
1561                 $s = str_replace( array( '%', '_' ), array( '\%', '\_' ), $s );
1562                 return $s;
1563         }
1564
1565         /**
1566          * LIKE statement wrapper, receives a variable-length argument list with parts of pattern to match
1567          * containing either string literals that will be escaped or tokens returned by anyChar() or anyString().
1568          * Alternatively, the function could be provided with an array of aforementioned parameters.
1569          *
1570          * Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns a LIKE clause that searches
1571          * for subpages of 'My page title'.
1572          * Alternatively: $pattern = array( 'My_page_title/', $dbr->anyString() ); $query .= $dbr->buildLike( $pattern );
1573          *
1574          * @since 1.16
1575          * @return String: fully built LIKE statement
1576          */
1577         function buildLike() {
1578                 $params = func_get_args();
1579                 if (count($params) > 0 && is_array($params[0])) {
1580                         $params = $params[0];
1581                 }
1582
1583                 $s = '';
1584                 foreach( $params as $value) {
1585                         if( $value instanceof LikeMatch ) {
1586                                 $s .= $value->toString();
1587                         } else {
1588                                 $s .= $this->escapeLikeInternal( $value );
1589                         }
1590                 }
1591                 return " LIKE '" . $s . "' ";
1592         }
1593
1594         /**
1595          * Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
1596          */
1597         function anyChar() {
1598                 return new LikeMatch( '_' );
1599         }
1600
1601         /**
1602          * Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
1603          */
1604         function anyString() {
1605                 return new LikeMatch( '%' );
1606         }
1607
1608         /**
1609          * Returns an appropriately quoted sequence value for inserting a new row.
1610          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1611          * subclass will return an integer, and save the value for insertId()
1612          */
1613         function nextSequenceValue( $seqName ) {
1614                 return null;
1615         }
1616
1617         /**
1618          * USE INDEX clause.  Unlikely to be useful for anything but MySQL.  This
1619          * is only needed because a) MySQL must be as efficient as possible due to
1620          * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
1621          * which index to pick.  Anyway, other databases might have different
1622          * indexes on a given table.  So don't bother overriding this unless you're
1623          * MySQL.
1624          */
1625         function useIndexClause( $index ) {
1626                 return '';
1627         }
1628
1629         /**
1630          * REPLACE query wrapper
1631          * PostgreSQL simulates this with a DELETE followed by INSERT
1632          * $row is the row to insert, an associative array
1633          * $uniqueIndexes is an array of indexes. Each element may be either a
1634          * field name or an array of field names
1635          *
1636          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1637          * However if you do this, you run the risk of encountering errors which wouldn't have
1638          * occurred in MySQL
1639          *
1640          * @param $table String: The table to replace the row(s) in.
1641          * @param $uniqueIndexes Array: An associative array of indexes
1642          * @param $rows Array: Array of rows to replace
1643          * @param $fname String: Calling function name (use __METHOD__) for logs/profiling
1644          */
1645         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseBase::replace' ) {
1646                 $table = $this->tableName( $table );
1647
1648                 # Single row case
1649                 if ( !is_array( reset( $rows ) ) ) {
1650                         $rows = array( $rows );
1651                 }
1652
1653                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1654                 $first = true;
1655                 foreach ( $rows as $row ) {
1656                         if ( $first ) {
1657                                 $first = false;
1658                         } else {
1659                                 $sql .= ',';
1660                         }
1661                         $sql .= '(' . $this->makeList( $row ) . ')';
1662                 }
1663                 return $this->query( $sql, $fname );
1664         }
1665
1666         /**
1667          * DELETE where the condition is a join
1668          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1669          *
1670          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1671          * join condition matches, set $conds='*'
1672          *
1673          * DO NOT put the join condition in $conds
1674          *
1675          * @param $delTable String: The table to delete from.
1676          * @param $joinTable String: The other table.
1677          * @param $delVar String: The variable to join on, in the first table.
1678          * @param $joinVar String: The variable to join on, in the second table.
1679          * @param $conds Array: Condition array of field names mapped to variables, ANDed together in the WHERE clause
1680          * @param $fname String: Calling function name (use __METHOD__) for logs/profiling
1681          */
1682         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'DatabaseBase::deleteJoin' ) {
1683                 if ( !$conds ) {
1684                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
1685                 }
1686
1687                 $delTable = $this->tableName( $delTable );
1688                 $joinTable = $this->tableName( $joinTable );
1689                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1690                 if ( $conds != '*' ) {
1691                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1692                 }
1693
1694                 return $this->query( $sql, $fname );
1695         }
1696
1697         /**
1698          * Returns the size of a text field, or -1 for "unlimited"
1699          */
1700         function textFieldSize( $table, $field ) {
1701                 $table = $this->tableName( $table );
1702                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1703                 $res = $this->query( $sql, 'DatabaseBase::textFieldSize' );
1704                 $row = $this->fetchObject( $res );
1705
1706                 $m = array();
1707                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1708                         $size = $m[1];
1709                 } else {
1710                         $size = -1;
1711                 }
1712                 return $size;
1713         }
1714
1715         /**
1716          * A string to insert into queries to show that they're low-priority, like
1717          * MySQL's LOW_PRIORITY.  If no such feature exists, return an empty
1718          * string and nothing bad should happen.
1719          *
1720          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1721          */
1722         function lowPriorityOption() {
1723                 return '';
1724         }
1725
1726         /**
1727          * DELETE query wrapper
1728          *
1729          * Use $conds == "*" to delete all rows
1730          */
1731         function delete( $table, $conds, $fname = 'DatabaseBase::delete' ) {
1732                 if ( !$conds ) {
1733                         throw new DBUnexpectedError( $this, 'DatabaseBase::delete() called with no conditions' );
1734                 }
1735                 $table = $this->tableName( $table );
1736                 $sql = "DELETE FROM $table";
1737                 if ( $conds != '*' ) {
1738                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1739                 }
1740                 return $this->query( $sql, $fname );
1741         }
1742
1743         /**
1744          * INSERT SELECT wrapper
1745          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1746          * Source items may be literals rather than field names, but strings should be quoted with DatabaseBase::addQuotes()
1747          * $conds may be "*" to copy the whole table
1748          * srcTable may be an array of tables.
1749          */
1750         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabaseBase::insertSelect',
1751                 $insertOptions = array(), $selectOptions = array() )
1752         {
1753                 $destTable = $this->tableName( $destTable );
1754                 if ( is_array( $insertOptions ) ) {
1755                         $insertOptions = implode( ' ', $insertOptions );
1756                 }
1757                 if( !is_array( $selectOptions ) ) {
1758                         $selectOptions = array( $selectOptions );
1759                 }
1760                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1761                 if( is_array( $srcTable ) ) {
1762                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1763                 } else {
1764                         $srcTable = $this->tableName( $srcTable );
1765                 }
1766                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1767                         " SELECT $startOpts " . implode( ',', $varMap ) .
1768                         " FROM $srcTable $useIndex ";
1769                 if ( $conds != '*' ) {
1770                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1771                 }
1772                 $sql .= " $tailOpts";
1773                 return $this->query( $sql, $fname );
1774         }
1775
1776         /**
1777          * Construct a LIMIT query with optional offset.  This is used for query
1778          * pages.  The SQL should be adjusted so that only the first $limit rows
1779          * are returned.  If $offset is provided as well, then the first $offset
1780          * rows should be discarded, and the next $limit rows should be returned.
1781          * If the result of the query is not ordered, then the rows to be returned
1782          * are theoretically arbitrary.
1783          *
1784          * $sql is expected to be a SELECT, if that makes a difference.  For
1785          * UPDATE, limitResultForUpdate should be used.
1786          *
1787          * The version provided by default works in MySQL and SQLite.  It will very
1788          * likely need to be overridden for most other DBMSes.
1789          *
1790          * @param $sql String: SQL query we will append the limit too
1791          * @param $limit Integer: the SQL limit
1792          * @param $offset Integer the SQL offset (default false)
1793          */
1794         function limitResult( $sql, $limit, $offset=false ) {
1795                 if( !is_numeric( $limit ) ) {
1796                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1797                 }
1798                 return "$sql LIMIT "
1799                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1800                                 . "{$limit} ";
1801         }
1802         function limitResultForUpdate( $sql, $num ) {
1803                 return $this->limitResult( $sql, $num, 0 );
1804         }
1805
1806         /**
1807          * Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries
1808          * within the UNION construct.
1809          * @return Boolean
1810          */
1811         function unionSupportsOrderAndLimit() {
1812                 return true; // True for almost every DB supported
1813         }
1814
1815         /**
1816          * Construct a UNION query
1817          * This is used for providing overload point for other DB abstractions
1818          * not compatible with the MySQL syntax.
1819          * @param $sqls Array: SQL statements to combine
1820          * @param $all Boolean: use UNION ALL
1821          * @return String: SQL fragment
1822          */
1823         function unionQueries($sqls, $all) {
1824                 $glue = $all ? ') UNION ALL (' : ') UNION (';
1825                 return '('.implode( $glue, $sqls ) . ')';
1826         }
1827
1828         /**
1829          * Returns an SQL expression for a simple conditional.  This doesn't need
1830          * to be overridden unless CASE isn't supported in your DBMS.
1831          *
1832          * @param $cond String: SQL expression which will result in a boolean value
1833          * @param $trueVal String: SQL expression to return if true
1834          * @param $falseVal String: SQL expression to return if false
1835          * @return String: SQL fragment
1836          */
1837         function conditional( $cond, $trueVal, $falseVal ) {
1838                 return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
1839         }
1840
1841         /**
1842          * Returns a comand for str_replace function in SQL query.
1843          * Uses REPLACE() in MySQL
1844          *
1845          * @param $orig String: column to modify
1846          * @param $old String: column to seek
1847          * @param $new String: column to replace with
1848          */
1849         function strreplace( $orig, $old, $new ) {
1850                 return "REPLACE({$orig}, {$old}, {$new})";
1851         }
1852
1853         /**
1854          * Determines if the last failure was due to a deadlock
1855          * STUB
1856          */
1857         function wasDeadlock() {
1858                 return false;
1859         }
1860
1861         /**
1862          * Determines if the last query error was something that should be dealt
1863          * with by pinging the connection and reissuing the query.
1864          * STUB
1865          */
1866         function wasErrorReissuable() {
1867                 return false;
1868         }
1869
1870         /**
1871          * Determines if the last failure was due to the database being read-only.
1872          * STUB
1873          */
1874         function wasReadOnlyError() {
1875                 return false;
1876         }
1877
1878         /**
1879          * Perform a deadlock-prone transaction.
1880          *
1881          * This function invokes a callback function to perform a set of write
1882          * queries. If a deadlock occurs during the processing, the transaction
1883          * will be rolled back and the callback function will be called again.
1884          *
1885          * Usage:
1886          *   $dbw->deadlockLoop( callback, ... );
1887          *
1888          * Extra arguments are passed through to the specified callback function.
1889          *
1890          * Returns whatever the callback function returned on its successful,
1891          * iteration, or false on error, for example if the retry limit was
1892          * reached.
1893          */
1894         function deadlockLoop() {
1895                 $myFname = 'DatabaseBase::deadlockLoop';
1896
1897                 $this->begin();
1898                 $args = func_get_args();
1899                 $function = array_shift( $args );
1900                 $oldIgnore = $this->ignoreErrors( true );
1901                 $tries = DEADLOCK_TRIES;
1902                 if ( is_array( $function ) ) {
1903                         $fname = $function[0];
1904                 } else {
1905                         $fname = $function;
1906                 }
1907                 do {
1908                         $retVal = call_user_func_array( $function, $args );
1909                         $error = $this->lastError();
1910                         $errno = $this->lastErrno();
1911                         $sql = $this->lastQuery();
1912
1913                         if ( $errno ) {
1914                                 if ( $this->wasDeadlock() ) {
1915                                         # Retry
1916                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1917                                 } else {
1918                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1919                                 }
1920                         }
1921                 } while( $this->wasDeadlock() && --$tries > 0 );
1922                 $this->ignoreErrors( $oldIgnore );
1923                 if ( $tries <= 0 ) {
1924                         $this->rollback( $myFname );
1925                         $this->reportQueryError( $error, $errno, $sql, $fname );
1926                         return false;
1927                 } else {
1928                         $this->commit( $myFname );
1929                         return $retVal;
1930                 }
1931         }
1932
1933         /**
1934          * Do a SELECT MASTER_POS_WAIT()
1935          *
1936          * @param $pos MySQLMasterPos object
1937          * @param $timeout Integer: the maximum number of seconds to wait for synchronisation
1938          */
1939         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1940                 $fname = 'DatabaseBase::masterPosWait';
1941                 wfProfileIn( $fname );
1942
1943                 # Commit any open transactions
1944                 if ( $this->mTrxLevel ) {
1945                         $this->commit();
1946                 }
1947
1948                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1949                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1950                         if ( $wait > $timeout * 1e6 ) {
1951                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1952                                 wfProfileOut( $fname );
1953                                 return -1;
1954                         } elseif ( $wait > 0 ) {
1955                                 wfDebug( "Fake slave waiting $wait us\n" );
1956                                 usleep( $wait );
1957                                 wfProfileOut( $fname );
1958                                 return 1;
1959                         } else {
1960                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1961                                 wfProfileOut( $fname );
1962                                 return 0;
1963                         }
1964                 }
1965
1966                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1967                 $encFile = $this->addQuotes( $pos->file );
1968                 $encPos = intval( $pos->pos );
1969                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1970                 $res = $this->doQuery( $sql );
1971                 if ( $res && $row = $this->fetchRow( $res ) ) {
1972                         wfProfileOut( $fname );
1973                         return $row[0];
1974                 } else {
1975                         wfProfileOut( $fname );
1976                         return false;
1977                 }
1978         }
1979
1980         /**
1981          * Get the position of the master from SHOW SLAVE STATUS
1982          */
1983         function getSlavePos() {
1984                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1985                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1986                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1987                         return $pos;
1988                 }
1989                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
1990                 $row = $this->fetchObject( $res );
1991                 if ( $row ) {
1992                         $pos = isset($row->Exec_master_log_pos) ? $row->Exec_master_log_pos : $row->Exec_Master_Log_Pos;
1993                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
1994                 } else {
1995                         return false;
1996                 }
1997         }
1998
1999         /**
2000          * Get the position of the master from SHOW MASTER STATUS
2001          */
2002         function getMasterPos() {
2003                 if ( $this->mFakeMaster ) {
2004                         return new MySQLMasterPos( 'fake', microtime( true ) );
2005                 }
2006                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
2007                 $row = $this->fetchObject( $res );
2008                 if ( $row ) {
2009                         return new MySQLMasterPos( $row->File, $row->Position );
2010                 } else {
2011                         return false;
2012                 }
2013         }
2014
2015         /**
2016          * Begin a transaction, committing any previously open transaction
2017          */
2018         function begin( $fname = 'DatabaseBase::begin' ) {
2019                 $this->query( 'BEGIN', $fname );
2020                 $this->mTrxLevel = 1;
2021         }
2022
2023         /**
2024          * End a transaction
2025          */
2026         function commit( $fname = 'DatabaseBase::commit' ) {
2027                 if( $this->mTrxLevel ) {
2028                         $this->query( 'COMMIT', $fname );
2029                         $this->mTrxLevel = 0;
2030                 }
2031         }
2032
2033         /**
2034          * Rollback a transaction.
2035          * No-op on non-transactional databases.
2036          */
2037         function rollback( $fname = 'DatabaseBase::rollback' ) {
2038                 if( $this->mTrxLevel ) {
2039                         $this->query( 'ROLLBACK', $fname, true );
2040                         $this->mTrxLevel = 0;
2041                 }
2042         }
2043
2044         /**
2045          * Begin a transaction, committing any previously open transaction
2046          * @deprecated use begin()
2047          */
2048         function immediateBegin( $fname = 'DatabaseBase::immediateBegin' ) {
2049                 wfDeprecated( __METHOD__ );
2050                 $this->begin();
2051         }
2052
2053         /**
2054          * Commit transaction, if one is open
2055          * @deprecated use commit()
2056          */
2057         function immediateCommit( $fname = 'DatabaseBase::immediateCommit' ) {
2058                 wfDeprecated( __METHOD__ );
2059                 $this->commit();
2060         }
2061
2062         /**
2063          * Creates a new table with structure copied from existing table
2064          * Note that unlike most database abstraction functions, this function does not
2065          * automatically append database prefix, because it works at a lower
2066          * abstraction level.
2067          *
2068          * @param $oldName String: name of table whose structure should be copied
2069          * @param $newName String: name of table to be created
2070          * @param $temporary Boolean: whether the new table should be temporary
2071          * @param $fname String: calling function name
2072          * @return Boolean: true if operation was successful
2073          */
2074         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabaseBase::duplicateTableStructure' ) {
2075                 throw new MWException( 'DatabaseBase::duplicateTableStructure is not implemented in descendant class' );
2076         }
2077
2078         /**
2079          * Return MW-style timestamp used for MySQL schema
2080          */
2081         function timestamp( $ts=0 ) {
2082                 return wfTimestamp(TS_MW,$ts);
2083         }
2084
2085         /**
2086          * Local database timestamp format or null
2087          */
2088         function timestampOrNull( $ts = null ) {
2089                 if( is_null( $ts ) ) {
2090                         return null;
2091                 } else {
2092                         return $this->timestamp( $ts );
2093                 }
2094         }
2095
2096         /**
2097          * @todo document
2098          */
2099         function resultObject( $result ) {
2100                 if( empty( $result ) ) {
2101                         return false;
2102                 } elseif ( $result instanceof ResultWrapper ) {
2103                         return $result;
2104                 } elseif ( $result === true ) {
2105                         // Successful write query
2106                         return $result;
2107                 } else {
2108                         return new ResultWrapper( $this, $result );
2109                 }
2110         }
2111
2112         /**
2113          * Return aggregated value alias
2114          */
2115         function aggregateValue ($valuedata,$valuename='value') {
2116                 return $valuename;
2117         }
2118
2119         /**
2120          * Returns a wikitext link to the DB's website, e.g.,
2121          *     return "[http://www.mysql.com/ MySQL]";
2122          * Should at least contain plain text, if for some reason
2123          * your database has no website.
2124          *
2125          * @return String: wikitext of a link to the server software's web site
2126          */
2127         public static function getSoftwareLink() {
2128                 throw new MWException( "A child class of DatabaseBase didn't implement getSoftwareLink(), shame on them" );
2129         }
2130
2131         /**
2132          * A string describing the current software version, like from
2133          * mysql_get_server_info().  Will be listed on Special:Version, etc.
2134          *
2135          * @return String: Version information from the database
2136          */
2137         abstract function getServerVersion();
2138
2139         /**
2140          * Ping the server and try to reconnect if it there is no connection
2141          *
2142          * @return bool Success or failure
2143          */
2144         function ping() {
2145                 # Stub.  Not essential to override.
2146                 return true;
2147         }
2148
2149         /**
2150          * Get slave lag.
2151          * Currently supported only by MySQL
2152          * @return Database replication lag in seconds
2153          */
2154         function getLag() {
2155                 return $this->mFakeSlaveLag;
2156         }
2157
2158         /**
2159          * Get status information from SHOW STATUS in an associative array
2160          */
2161         function getStatus($which="%") {
2162                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2163                 $status = array();
2164                 while ( $row = $this->fetchObject( $res ) ) {
2165                         $status[$row->Variable_name] = $row->Value;
2166                 }
2167                 return $status;
2168         }
2169
2170         /**
2171          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2172          */
2173         function maxListLen() {
2174                 return 0;
2175         }
2176
2177         function encodeBlob($b) {
2178                 return $b;
2179         }
2180
2181         function decodeBlob($b) {
2182                 return $b;
2183         }
2184
2185         /**
2186          * Override database's default connection timeout.  May be useful for very
2187          * long batch queries such as full-wiki dumps, where a single query reads
2188          * out over hours or days.  May or may not be necessary for non-MySQL
2189          * databases.  For most purposes, leaving it as a no-op should be fine.
2190          *
2191          * @param $timeout Integer in seconds
2192          */
2193         public function setTimeout( $timeout ) {}
2194
2195         /**
2196          * Read and execute SQL commands from a file.
2197          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2198          * @param $filename String: File name to open
2199          * @param $lineCallback Callback: Optional function called before reading each line
2200          * @param $resultCallback Callback: Optional function called for each MySQL result
2201          */
2202         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2203                 $fp = fopen( $filename, 'r' );
2204                 if ( false === $fp ) {
2205                         if (!defined("MEDIAWIKI_INSTALL"))
2206                                 throw new MWException( "Could not open \"{$filename}\".\n" );
2207                         else
2208                                 return "Could not open \"{$filename}\".\n";
2209                 }
2210                 try {
2211                         $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2212                 }
2213                 catch( MWException $e ) {
2214                         if ( defined("MEDIAWIKI_INSTALL") ) {
2215                                 $error = $e->getMessage();
2216                         } else {
2217                                 fclose( $fp );
2218                                 throw $e;
2219                         }
2220                 }
2221
2222                 fclose( $fp );
2223                 return $error;
2224         }
2225
2226         /**
2227          * Get the full path of a patch file. Originally based on archive()
2228          * from updaters.inc. Keep in mind this always returns a patch, as
2229          * it fails back to MySQL if no DB-specific patch can be found
2230          *
2231          * @param $patch String The name of the patch, like patch-something.sql
2232          * @return String Full path to patch file
2233          */
2234         public static function patchPath( $patch ) {
2235                 global $wgDBtype, $IP;
2236                 if ( file_exists( "$IP/maintenance/$wgDBtype/archives/$patch" ) ) {
2237                         return "$IP/maintenance/$wgDBtype/archives/$patch";
2238                 } else {
2239                         return "$IP/maintenance/archives/$patch";
2240                 }
2241         }
2242
2243         /**
2244          * Read and execute commands from an open file handle
2245          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2246          * @param $fp String: File handle
2247          * @param $lineCallback Callback: Optional function called before reading each line
2248          * @param $resultCallback Callback: Optional function called for each MySQL result
2249          */
2250         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2251                 $cmd = "";
2252                 $done = false;
2253                 $dollarquote = false;
2254
2255                 while ( ! feof( $fp ) ) {
2256                         if ( $lineCallback ) {
2257                                 call_user_func( $lineCallback );
2258                         }
2259                         $line = trim( fgets( $fp, 1024 ) );
2260                         $sl = strlen( $line ) - 1;
2261
2262                         if ( $sl < 0 ) { continue; }
2263                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2264
2265                         ## Allow dollar quoting for function declarations
2266                         if (substr($line,0,4) == '$mw$') {
2267                                 if ($dollarquote) {
2268                                         $dollarquote = false;
2269                                         $done = true;
2270                                 }
2271                                 else {
2272                                         $dollarquote = true;
2273                                 }
2274                         }
2275                         else if (!$dollarquote) {
2276                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2277                                         $done = true;
2278                                         $line = substr( $line, 0, $sl );
2279                                 }
2280                         }
2281
2282                         if ( $cmd != '' ) { $cmd .= ' '; }
2283                         $cmd .= "$line\n";
2284
2285                         if ( $done ) {
2286                                 $cmd = str_replace(';;', ";", $cmd);
2287                                 $cmd = $this->replaceVars( $cmd );
2288                                 $res = $this->query( $cmd, __METHOD__ );
2289                                 if ( $resultCallback ) {
2290                                         call_user_func( $resultCallback, $res, $this );
2291                                 }
2292
2293                                 if ( false === $res ) {
2294                                         $err = $this->lastError();
2295                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2296                                 }
2297
2298                                 $cmd = '';
2299                                 $done = false;
2300                         }
2301                 }
2302                 return true;
2303         }
2304
2305
2306         /**
2307          * Replace variables in sourced SQL
2308          */
2309         protected function replaceVars( $ins ) {
2310                 $varnames = array(
2311                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2312                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2313                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2314                 );
2315
2316                 // Ordinary variables
2317                 foreach ( $varnames as $var ) {
2318                         if( isset( $GLOBALS[$var] ) ) {
2319                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2320                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2321                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2322                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2323                         }
2324                 }
2325
2326                 // Table prefixes
2327                 $ins = preg_replace_callback( '!/\*(?:\$wgDBprefix|_)\*/([a-zA-Z_0-9]*)!',
2328                         array( $this, 'tableNameCallback' ), $ins );
2329
2330                 // Index names
2331                 $ins = preg_replace_callback( '!/\*i\*/([a-zA-Z_0-9]*)!',
2332                         array( $this, 'indexNameCallback' ), $ins );
2333                 return $ins;
2334         }
2335
2336         /**
2337          * Table name callback
2338          * @private
2339          */
2340         protected function tableNameCallback( $matches ) {
2341                 return $this->tableName( $matches[1] );
2342         }
2343
2344         /**
2345          * Index name callback
2346          */
2347         protected function indexNameCallback( $matches ) {
2348                 return $this->indexName( $matches[1] );
2349         }
2350
2351         /**
2352          * Build a concatenation list to feed into a SQL query
2353          * @param $stringList Array: list of raw SQL expressions; caller is responsible for any quoting
2354          * @return String
2355          */
2356         function buildConcat( $stringList ) {
2357                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2358         }
2359
2360         /**
2361          * Acquire a named lock
2362          *
2363          * Abstracted from Filestore::lock() so child classes can implement for
2364          * their own needs.
2365          *
2366          * @param $lockName String: name of lock to aquire
2367          * @param $method String: name of method calling us
2368          * @param $timeout Integer: timeout
2369          * @return Boolean
2370          */
2371         public function lock( $lockName, $method, $timeout = 5 ) {
2372                 return true;
2373         }
2374
2375         /**
2376          * Release a lock.
2377          *
2378          * @param $lockName String: Name of lock to release
2379          * @param $method String: Name of method calling us
2380          *
2381          * @return Returns 1 if the lock was released, 0 if the lock was not established
2382          * by this thread (in which case the lock is not released), and NULL if the named
2383          * lock did not exist
2384          */
2385         public function unlock( $lockName, $method ) {
2386                 return true;
2387         }
2388
2389         /**
2390          * Lock specific tables
2391          *
2392          * @param $read Array of tables to lock for read access
2393          * @param $write Array of tables to lock for write access
2394          * @param $method String name of caller
2395          * @param $lowPriority bool Whether to indicate writes to be LOW PRIORITY
2396          */
2397         public function lockTables( $read, $write, $method, $lowPriority = true ) {
2398                 return true;
2399         }
2400
2401         /**
2402          * Unlock specific tables
2403          *
2404          * @param $method String the caller
2405          */
2406         public function unlockTables( $method ) {
2407                 return true;
2408         }
2409
2410         /**
2411          * Get search engine class. All subclasses of this need to implement this
2412          * if they wish to use searching.
2413          *
2414          * @return String
2415          */
2416         public function getSearchEngine() {
2417                 return 'SearchEngineDummy';
2418         }
2419
2420         /**
2421          * Allow or deny "big selects" for this session only. This is done by setting
2422          * the sql_big_selects session variable.
2423          *
2424          * This is a MySQL-specific feature.
2425          *
2426          * @param $value Mixed: true for allow, false for deny, or "default" to restore the initial value
2427          */
2428         public function setBigSelects( $value = true ) {
2429                 // no-op
2430         }
2431 }
2432
2433
2434 /******************************************************************************
2435  * Utility classes
2436  *****************************************************************************/
2437
2438 /**
2439  * Utility class.
2440  * @ingroup Database
2441  */
2442 class DBObject {
2443         public $mData;
2444
2445         function DBObject($data) {
2446                 $this->mData = $data;
2447         }
2448
2449         function isLOB() {
2450                 return false;
2451         }
2452
2453         function data() {
2454                 return $this->mData;
2455         }
2456 }
2457
2458 /**
2459  * Utility class
2460  * @ingroup Database
2461  *
2462  * This allows us to distinguish a blob from a normal string and an array of strings
2463  */
2464 class Blob {
2465         private $mData;
2466         function __construct($data) {
2467                 $this->mData = $data;
2468         }
2469         function fetch() {
2470                 return $this->mData;
2471         }
2472 }
2473
2474 /**
2475  * Utility class.
2476  * @ingroup Database
2477  */
2478 class MySQLField {
2479         private $name, $tablename, $default, $max_length, $nullable,
2480                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2481         function __construct ($info) {
2482                 $this->name = $info->name;
2483                 $this->tablename = $info->table;
2484                 $this->default = $info->def;
2485                 $this->max_length = $info->max_length;
2486                 $this->nullable = !$info->not_null;
2487                 $this->is_pk = $info->primary_key;
2488                 $this->is_unique = $info->unique_key;
2489                 $this->is_multiple = $info->multiple_key;
2490                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2491                 $this->type = $info->type;
2492         }
2493
2494         function name() {
2495                 return $this->name;
2496         }
2497
2498         function tableName() {
2499                 return $this->tableName;
2500         }
2501
2502         function defaultValue() {
2503                 return $this->default;
2504         }
2505
2506         function maxLength() {
2507                 return $this->max_length;
2508         }
2509
2510         function nullable() {
2511                 return $this->nullable;
2512         }
2513
2514         function isKey() {
2515                 return $this->is_key;
2516         }
2517
2518         function isMultipleKey() {
2519                 return $this->is_multiple;
2520         }
2521
2522         function type() {
2523                 return $this->type;
2524         }
2525 }
2526
2527 /******************************************************************************
2528  * Error classes
2529  *****************************************************************************/
2530
2531 /**
2532  * Database error base class
2533  * @ingroup Database
2534  */
2535 class DBError extends MWException {
2536         public $db;
2537
2538         /**
2539          * Construct a database error
2540          * @param $db Database object which threw the error
2541          * @param $error A simple error message to be used for debugging
2542          */
2543         function __construct( DatabaseBase &$db, $error ) {
2544                 $this->db =& $db;
2545                 parent::__construct( $error );
2546         }
2547
2548         function getText() {
2549                 global $wgShowDBErrorBacktrace;
2550                 $s = $this->getMessage() . "\n";
2551                 if ( $wgShowDBErrorBacktrace ) {
2552                         $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
2553                 }
2554                 return $s;
2555         }
2556 }
2557
2558 /**
2559  * @ingroup Database
2560  */
2561 class DBConnectionError extends DBError {
2562         public $error;
2563
2564         function __construct( DatabaseBase &$db, $error = 'unknown error' ) {
2565                 $msg = 'DB connection error';
2566                 if ( trim( $error ) != '' ) {
2567                         $msg .= ": $error";
2568                 }
2569                 $this->error = $error;
2570                 parent::__construct( $db, $msg );
2571         }
2572
2573         function useOutputPage() {
2574                 // Not likely to work
2575                 return false;
2576         }
2577
2578         function useMessageCache() {
2579                 // Not likely to work
2580                 return false;
2581         }
2582
2583         function getLogMessage() {
2584                 # Don't send to the exception log
2585                 return false;
2586         }
2587
2588         function getPageTitle() {
2589                 global $wgSitename, $wgLang;
2590                 $header = "$wgSitename has a problem";
2591                 if ( $wgLang instanceof Language ) {
2592                         $header = htmlspecialchars( $wgLang->getMessage( 'dberr-header' ) );
2593                 }
2594
2595                 return $header;
2596         }
2597
2598         function getHTML() {
2599                 global $wgLang, $wgMessageCache, $wgUseFileCache, $wgShowDBErrorBacktrace;
2600
2601                 $sorry = 'Sorry! This site is experiencing technical difficulties.';
2602                 $again = 'Try waiting a few minutes and reloading.';
2603                 $info  = '(Can\'t contact the database server: $1)';
2604
2605                 if ( $wgLang instanceof Language ) {
2606                         $sorry = htmlspecialchars( $wgLang->getMessage( 'dberr-problems' ) );
2607                         $again = htmlspecialchars( $wgLang->getMessage( 'dberr-again' ) );
2608                         $info  = htmlspecialchars( $wgLang->getMessage( 'dberr-info' ) );
2609                 }
2610
2611                 # No database access
2612                 if ( is_object( $wgMessageCache ) ) {
2613                         $wgMessageCache->disable();
2614                 }
2615
2616                 if ( trim( $this->error ) == '' ) {
2617                         $this->error = $this->db->getProperty('mServer');
2618                 }
2619
2620                 $noconnect = "<p><strong>$sorry</strong><br />$again</p><p><small>$info</small></p>";
2621                 $text = str_replace( '$1', $this->error, $noconnect );
2622
2623                 if ( $wgShowDBErrorBacktrace ) {
2624                         $text .= '<p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) );
2625                 }
2626
2627                 $extra = $this->searchForm();
2628
2629                 if( $wgUseFileCache ) {
2630                         try {
2631                                 $cache = $this->fileCachedPage();
2632                                 # Cached version on file system?
2633                                 if( $cache !== null ) {
2634                                         # Hack: extend the body for error messages
2635                                         $cache = str_replace( array('</html>','</body>'), '', $cache );
2636                                         # Add cache notice...
2637                                         $cachederror = "This is a cached copy of the requested page, and may not be up to date. ";
2638                                         # Localize it if possible...
2639                                         if( $wgLang instanceof Language ) {
2640                                                 $cachederror = htmlspecialchars( $wgLang->getMessage( 'dberr-cachederror' ) );
2641                                         }
2642                                         $warning = "<div style='color:red;font-size:150%;font-weight:bold;'>$cachederror</div>";
2643                                         # Output cached page with notices on bottom and re-close body
2644                                         return "{$cache}{$warning}<hr />$text<hr />$extra</body></html>";
2645                                 }
2646                         } catch( MWException $e ) {
2647                                 // Do nothing, just use the default page
2648                         }
2649                 }
2650                 # Headers needed here - output is just the error message
2651                 return $this->htmlHeader()."$text<hr />$extra".$this->htmlFooter();
2652         }
2653
2654         function searchForm() {
2655                 global $wgSitename, $wgServer, $wgLang, $wgInputEncoding;
2656                 $usegoogle = "You can try searching via Google in the meantime.";
2657                 $outofdate = "Note that their indexes of our content may be out of date.";
2658                 $googlesearch = "Search";
2659
2660                 if ( $wgLang instanceof Language ) {
2661                         $usegoogle = htmlspecialchars( $wgLang->getMessage( 'dberr-usegoogle' ) );
2662                         $outofdate = htmlspecialchars( $wgLang->getMessage( 'dberr-outofdate' ) );
2663                         $googlesearch  = htmlspecialchars( $wgLang->getMessage( 'searchbutton' ) );
2664                 }
2665
2666                 $search = htmlspecialchars(@$_REQUEST['search']);
2667
2668                 $trygoogle = <<<EOT
2669 <div style="margin: 1.5em">$usegoogle<br />
2670 <small>$outofdate</small></div>
2671 <!-- SiteSearch Google -->
2672 <form method="get" action="http://www.google.com/search" id="googlesearch">
2673     <input type="hidden" name="domains" value="$wgServer" />
2674     <input type="hidden" name="num" value="50" />
2675     <input type="hidden" name="ie" value="$wgInputEncoding" />
2676     <input type="hidden" name="oe" value="$wgInputEncoding" />
2677
2678     <input type="text" name="q" size="31" maxlength="255" value="$search" />
2679     <input type="submit" name="btnG" value="$googlesearch" />
2680   <div>
2681     <input type="radio" name="sitesearch" id="gwiki" value="$wgServer" checked="checked" /><label for="gwiki">$wgSitename</label>
2682     <input type="radio" name="sitesearch" id="gWWW" value="" /><label for="gWWW">WWW</label>
2683   </div>
2684 </form>
2685 <!-- SiteSearch Google -->
2686 EOT;
2687                 return $trygoogle;
2688         }
2689
2690         function fileCachedPage() {
2691                 global $wgTitle, $title, $wgLang, $wgOut;
2692                 if( $wgOut->isDisabled() ) return; // Done already?
2693                 $mainpage = 'Main Page';
2694                 if ( $wgLang instanceof Language ) {
2695                         $mainpage    = htmlspecialchars( $wgLang->getMessage( 'mainpage' ) );
2696                 }
2697
2698                 if( $wgTitle ) {
2699                         $t =& $wgTitle;
2700                 } elseif( $title ) {
2701                         $t = Title::newFromURL( $title );
2702                 } else {
2703                         $t = Title::newFromText( $mainpage );
2704                 }
2705
2706                 $cache = new HTMLFileCache( $t );
2707                 if( $cache->isFileCached() ) {
2708                         return $cache->fetchPageText();
2709                 } else {
2710                         return '';
2711                 }
2712         }
2713
2714         function htmlBodyOnly() {
2715                 return true;
2716         }
2717
2718 }
2719
2720 /**
2721  * @ingroup Database
2722  */
2723 class DBQueryError extends DBError {
2724         public $error, $errno, $sql, $fname;
2725
2726         function __construct( DatabaseBase &$db, $error, $errno, $sql, $fname ) {
2727                 $message = "A database error has occurred\n" .
2728                   "Query: $sql\n" .
2729                   "Function: $fname\n" .
2730                   "Error: $errno $error\n";
2731
2732                 parent::__construct( $db, $message );
2733                 $this->error = $error;
2734                 $this->errno = $errno;
2735                 $this->sql = $sql;
2736                 $this->fname = $fname;
2737         }
2738
2739         function getText() {
2740                 global $wgShowDBErrorBacktrace;
2741                 if ( $this->useMessageCache() ) {
2742                         $s = wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2743                                 htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2744                         if ( $wgShowDBErrorBacktrace ) {
2745                                 $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
2746                         }
2747                         return $s;
2748                 } else {
2749                         return parent::getText();
2750                 }
2751         }
2752
2753         function getSQL() {
2754                 global $wgShowSQLErrors;
2755                 if( !$wgShowSQLErrors ) {
2756                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2757                 } else {
2758                         return $this->sql;
2759                 }
2760         }
2761
2762         function getLogMessage() {
2763                 # Don't send to the exception log
2764                 return false;
2765         }
2766
2767         function getPageTitle() {
2768                 return $this->msg( 'databaseerror', 'Database error' );
2769         }
2770
2771         function getHTML() {
2772                 global $wgShowDBErrorBacktrace;
2773                 if ( $this->useMessageCache() ) {
2774                         $s = wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2775                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2776                 } else {
2777                         $s = nl2br( htmlspecialchars( $this->getMessage() ) );
2778                 }
2779                 if ( $wgShowDBErrorBacktrace ) {
2780                         $s .= '<p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) );
2781                 }
2782                 return $s;
2783         }
2784 }
2785
2786 /**
2787  * @ingroup Database
2788  */
2789 class DBUnexpectedError extends DBError {}
2790
2791
2792 /**
2793  * Result wrapper for grabbing data queried by someone else
2794  * @ingroup Database
2795  */
2796 class ResultWrapper implements Iterator {
2797         var $db, $result, $pos = 0, $currentRow = null;
2798
2799         /**
2800          * Create a new result object from a result resource and a Database object
2801          */
2802         function ResultWrapper( $database, $result ) {
2803                 $this->db = $database;
2804                 if ( $result instanceof ResultWrapper ) {
2805                         $this->result = $result->result;
2806                 } else {
2807                         $this->result = $result;
2808                 }
2809         }
2810
2811         /**
2812          * Get the number of rows in a result object
2813          */
2814         function numRows() {
2815                 return $this->db->numRows( $this );
2816         }
2817
2818         /**
2819          * Fetch the next row from the given result object, in object form.
2820          * Fields can be retrieved with $row->fieldname, with fields acting like
2821          * member variables.
2822          *
2823          * @return MySQL row object
2824          * @throws DBUnexpectedError Thrown if the database returns an error
2825          */
2826         function fetchObject() {
2827                 return $this->db->fetchObject( $this );
2828         }
2829
2830         /**
2831          * Fetch the next row from the given result object, in associative array
2832          * form.  Fields are retrieved with $row['fieldname'].
2833          *
2834          * @return MySQL row object
2835          * @throws DBUnexpectedError Thrown if the database returns an error
2836          */
2837         function fetchRow() {
2838                 return $this->db->fetchRow( $this );
2839         }
2840
2841         /**
2842          * Free a result object
2843          */
2844         function free() {
2845                 $this->db->freeResult( $this );
2846                 unset( $this->result );
2847                 unset( $this->db );
2848         }
2849
2850         /**
2851          * Change the position of the cursor in a result object
2852          * See mysql_data_seek()
2853          */
2854         function seek( $row ) {
2855                 $this->db->dataSeek( $this, $row );
2856         }
2857
2858         /*********************
2859          * Iterator functions
2860          * Note that using these in combination with the non-iterator functions
2861          * above may cause rows to be skipped or repeated.
2862          */
2863
2864         function rewind() {
2865                 if ($this->numRows()) {
2866                         $this->db->dataSeek($this, 0);
2867                 }
2868                 $this->pos = 0;
2869                 $this->currentRow = null;
2870         }
2871
2872         function current() {
2873                 if ( is_null( $this->currentRow ) ) {
2874                         $this->next();
2875                 }
2876                 return $this->currentRow;
2877         }
2878
2879         function key() {
2880                 return $this->pos;
2881         }
2882
2883         function next() {
2884                 $this->pos++;
2885                 $this->currentRow = $this->fetchObject();
2886                 return $this->currentRow;
2887         }
2888
2889         function valid() {
2890                 return $this->current() !== false;
2891         }
2892 }
2893
2894 /* Overloads the relevant methods of the real ResultsWrapper so it
2895  * doesn't go anywhere near an actual database.
2896  */
2897 class FakeResultWrapper extends ResultWrapper {
2898
2899         var $result     = array();
2900         var $db         = null; // And it's going to stay that way :D
2901         var $pos        = 0;
2902         var $currentRow = null;
2903
2904         function __construct( $array ){
2905                 $this->result = $array;
2906         }
2907
2908         function numRows() {
2909                 return count( $this->result );
2910         }
2911
2912         function fetchRow() {
2913                 $this->currentRow = $this->result[$this->pos++];
2914                 return $this->currentRow;
2915         }
2916
2917         function seek( $row ) {
2918                 $this->pos = $row;
2919         }
2920
2921         function free() {}
2922
2923         // Callers want to be able to access fields with $this->fieldName
2924         function fetchObject(){
2925                 $this->currentRow = $this->result[$this->pos++];
2926                 return (object)$this->currentRow;
2927         }
2928
2929         function rewind() {
2930                 $this->pos = 0;
2931                 $this->currentRow = null;
2932         }
2933 }
2934
2935 /**
2936  * Used by DatabaseBase::buildLike() to represent characters that have special meaning in SQL LIKE clauses
2937  * and thus need no escaping. Don't instantiate it manually, use DatabaseBase::anyChar() and anyString() instead.
2938  */
2939 class LikeMatch {
2940         private $str;
2941
2942         public function __construct( $s ) {
2943                 $this->str = $s;
2944         }
2945
2946         public function toString() {
2947                 return $this->str;
2948         }
2949 }