includes/db/DatabaseSqlite.php

   1 <?php
   2 /**
   3  * This is the SQLite database abstraction layer.
   4  * See maintenance/sqlite/README for development notes and other specific information
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  * @ingroup Database
  23  */
  24
  25 /**
  26  * @ingroup Database
  27  */
  28 class DatabaseSqlite extends DatabaseBase {
  29         private static $fulltextEnabled = null;
  30
  31         var $mAffectedRows;
  32         var $mLastResult;
  33         var $mDatabaseFile;
  34         var $mName;
  35
  36         /**
  37          * @var PDO
  38          */
  39         protected $mConn;
  40
  41         function __construct( $p = null ) {
  42                 global $wgSharedDB;
  43
  44                 if ( !is_array( $p ) ) { // legacy calling pattern
  45                         wfDeprecated( __METHOD__ . " method called without parameter array.", "1.22" );
  46                         $args = func_get_args();
  47                         $p = array(
  48                                 'host' => isset( $args[0] ) ? $args[0] : false,
  49                                 'user' => isset( $args[1] ) ? $args[1] : false,
  50                                 'password' => isset( $args[2] ) ? $args[2] : false,
  51                                 'dbname' => isset( $args[3] ) ? $args[3] : false,
  52                                 'flags' => isset( $args[4] ) ? $args[4] : 0,
  53                                 'tablePrefix' => isset( $args[5] ) ? $args[5] : 'get from global',
  54                                 'foreign' => isset( $args[6] ) ? $args[6] : false
  55                         );
  56                 }
  57                 $this->mName = $p['dbname'];
  58                 parent::__construct( $p );
  59                 // parent doesn't open when $user is false, but we can work with $dbName
  60                 if ( $p['dbname'] && !$this->isOpen() ) {
  61                         if ( $this->open( $p['host'], $p['user'], $p['password'], $p['dbname'] ) ) {
  62                                 if ( $wgSharedDB ) {
  63                                         $this->attachDatabase( $wgSharedDB );
  64                                 }
  65                         }
  66                 }
  67         }
  68
  69         /**
  70          * @return string
  71          */
  72         function getType() {
  73                 return 'sqlite';
  74         }
  75
  76         /**
  77          * @todo Check if it should be true like parent class
  78          *
  79          * @return bool
  80          */
  81         function implicitGroupby() {
  82                 return false;
  83         }
  84
  85         /** Open an SQLite database and return a resource handle to it
  86          *  NOTE: only $dbName is used, the other parameters are irrelevant for SQLite databases
  87          *
  88          * @param string $server
  89          * @param string $user
  90          * @param string $pass
  91          * @param string $dbName
  92          *
  93          * @throws DBConnectionError
  94          * @return PDO
  95          */
  96         function open( $server, $user, $pass, $dbName ) {
  97                 global $wgSQLiteDataDir;
  98
  99                 $this->close();
 100                 $fileName = self::generateFileName( $wgSQLiteDataDir, $dbName );
 101                 if ( !is_readable( $fileName ) ) {
 102                         $this->mConn = false;
 103                         throw new DBConnectionError( $this, "SQLite database not accessible" );
 104                 }
 105                 $this->openFile( $fileName );
 106
 107                 return $this->mConn;
 108         }
 109
 110         /**
 111          * Opens a database file
 112          *
 113          * @param $fileName string
 114          *
 115          * @throws DBConnectionError
 116          * @return PDO|bool SQL connection or false if failed
 117          */
 118         function openFile( $fileName ) {
 119                 $this->mDatabaseFile = $fileName;
 120                 try {
 121                         if ( $this->mFlags & DBO_PERSISTENT ) {
 122                                 $this->mConn = new PDO( "sqlite:$fileName", '', '',
 123                                         array( PDO::ATTR_PERSISTENT => true ) );
 124                         } else {
 125                                 $this->mConn = new PDO( "sqlite:$fileName", '', '' );
 126                         }
 127                 } catch ( PDOException $e ) {
 128                         $err = $e->getMessage();
 129                 }
 130                 if ( !$this->mConn ) {
 131                         wfDebug( "DB connection error: $err\n" );
 132                         throw new DBConnectionError( $this, $err );
 133                 }
 134                 $this->mOpened = !!$this->mConn;
 135                 # set error codes only, don't raise exceptions
 136                 if ( $this->mOpened ) {
 137                         $this->mConn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
 138                         # Enforce LIKE to be case sensitive, just like MySQL
 139                         $this->query( 'PRAGMA case_sensitive_like = 1' );
 140
 141                         return true;
 142                 }
 143         }
 144
 145         /**
 146          * Does not actually close the connection, just destroys the reference for GC to do its work
 147          * @return bool
 148          */
 149         protected function closeConnection() {
 150                 $this->mConn = null;
 151
 152                 return true;
 153         }
 154
 155         /**
 156          * Generates a database file name. Explicitly public for installer.
 157          * @param string $dir Directory where database resides
 158          * @param string $dbName Database name
 159          * @return String
 160          */
 161         public static function generateFileName( $dir, $dbName ) {
 162                 return "$dir/$dbName.sqlite";
 163         }
 164
 165         /**
 166          * Check if the searchindext table is FTS enabled.
 167          * @return bool False if not enabled.
 168          */
 169         function checkForEnabledSearch() {
 170                 if ( self::$fulltextEnabled === null ) {
 171                         self::$fulltextEnabled = false;
 172                         $table = $this->tableName( 'searchindex' );
 173                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 174                         if ( $res ) {
 175                                 $row = $res->fetchRow();
 176                                 self::$fulltextEnabled = stristr( $row['sql'], 'fts' ) !== false;
 177                         }
 178                 }
 179
 180                 return self::$fulltextEnabled;
 181         }
 182
 183         /**
 184          * Returns version of currently supported SQLite fulltext search module or false if none present.
 185          * @return String
 186          */
 187         static function getFulltextSearchModule() {
 188                 static $cachedResult = null;
 189                 if ( $cachedResult !== null ) {
 190                         return $cachedResult;
 191                 }
 192                 $cachedResult = false;
 193                 $table = 'dummy_search_test';
 194
 195                 $db = new DatabaseSqliteStandalone( ':memory:' );
 196
 197                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 198                         $cachedResult = 'FTS3';
 199                 }
 200                 $db->close();
 201
 202                 return $cachedResult;
 203         }
 204
 205         /**
 206          * Attaches external database to our connection, see http://sqlite.org/lang_attach.html
 207          * for details.
 208          *
 209          * @param string $name database name to be used in queries like
 210          *   SELECT foo FROM dbname.table
 211          * @param string $file database file name. If omitted, will be generated
 212          *   using $name and $wgSQLiteDataDir
 213          * @param string $fname calling function name
 214          *
 215          * @return ResultWrapper
 216          */
 217         function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 218                 global $wgSQLiteDataDir;
 219                 if ( !$file ) {
 220                         $file = self::generateFileName( $wgSQLiteDataDir, $name );
 221                 }
 222                 $file = $this->addQuotes( $file );
 223
 224                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 225         }
 226
 227         /**
 228          * @see DatabaseBase::isWriteQuery()
 229          *
 230          * @param $sql string
 231          *
 232          * @return bool
 233          */
 234         function isWriteQuery( $sql ) {
 235                 return parent::isWriteQuery( $sql ) && !preg_match( '/^ATTACH\b/i', $sql );
 236         }
 237
 238         /**
 239          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 240          *
 241          * @param $sql string
 242          *
 243          * @return ResultWrapper
 244          */
 245         protected function doQuery( $sql ) {
 246                 $res = $this->mConn->query( $sql );
 247                 if ( $res === false ) {
 248                         return false;
 249                 } else {
 250                         $r = $res instanceof ResultWrapper ? $res->result : $res;
 251                         $this->mAffectedRows = $r->rowCount();
 252                         $res = new ResultWrapper( $this, $r->fetchAll() );
 253                 }
 254
 255                 return $res;
 256         }
 257
 258         /**
 259          * @param $res ResultWrapper
 260          */
 261         function freeResult( $res ) {
 262                 if ( $res instanceof ResultWrapper ) {
 263                         $res->result = null;
 264                 } else {
 265                         $res = null;
 266                 }
 267         }
 268
 269         /**
 270          * @param $res ResultWrapper
 271          * @return object|bool
 272          */
 273         function fetchObject( $res ) {
 274                 if ( $res instanceof ResultWrapper ) {
 275                         $r =& $res->result;
 276                 } else {
 277                         $r =& $res;
 278                 }
 279
 280                 $cur = current( $r );
 281                 if ( is_array( $cur ) ) {
 282                         next( $r );
 283                         $obj = new stdClass;
 284                         foreach ( $cur as $k => $v ) {
 285                                 if ( !is_numeric( $k ) ) {
 286                                         $obj->$k = $v;
 287                                 }
 288                         }
 289
 290                         return $obj;
 291                 }
 292
 293                 return false;
 294         }
 295
 296         /**
 297          * @param $res ResultWrapper
 298          * @return array|bool
 299          */
 300         function fetchRow( $res ) {
 301                 if ( $res instanceof ResultWrapper ) {
 302                         $r =& $res->result;
 303                 } else {
 304                         $r =& $res;
 305                 }
 306                 $cur = current( $r );
 307                 if ( is_array( $cur ) ) {
 308                         next( $r );
 309
 310                         return $cur;
 311                 }
 312
 313                 return false;
 314         }
 315
 316         /**
 317          * The PDO::Statement class implements the array interface so count() will work
 318          *
 319          * @param $res ResultWrapper
 320          *
 321          * @return int
 322          */
 323         function numRows( $res ) {
 324                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 325
 326                 return count( $r );
 327         }
 328
 329         /**
 330          * @param $res ResultWrapper
 331          * @return int
 332          */
 333         function numFields( $res ) {
 334                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 335
 336                 return is_array( $r ) ? count( $r[0] ) : 0;
 337         }
 338
 339         /**
 340          * @param $res ResultWrapper
 341          * @param $n
 342          * @return bool
 343          */
 344         function fieldName( $res, $n ) {
 345                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 346                 if ( is_array( $r ) ) {
 347                         $keys = array_keys( $r[0] );
 348
 349                         return $keys[$n];
 350                 }
 351
 352                 return false;
 353         }
 354
 355         /**
 356          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 357          *
 358          * @param $name
 359          * @param $format String
 360          * @return string
 361          */
 362         function tableName( $name, $format = 'quoted' ) {
 363                 // table names starting with sqlite_ are reserved
 364                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 365                         return $name;
 366                 }
 367
 368                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 369         }
 370
 371         /**
 372          * Index names have DB scope
 373          *
 374          * @param $index string
 375          *
 376          * @return string
 377          */
 378         function indexName( $index ) {
 379                 return $index;
 380         }
 381
 382         /**
 383          * This must be called after nextSequenceVal
 384          *
 385          * @return int
 386          */
 387         function insertId() {
 388                 // PDO::lastInsertId yields a string :(
 389                 return intval( $this->mConn->lastInsertId() );
 390         }
 391
 392         /**
 393          * @param $res ResultWrapper
 394          * @param $row
 395          */
 396         function dataSeek( $res, $row ) {
 397                 if ( $res instanceof ResultWrapper ) {
 398                         $r =& $res->result;
 399                 } else {
 400                         $r =& $res;
 401                 }
 402                 reset( $r );
 403                 if ( $row > 0 ) {
 404                         for ( $i = 0; $i < $row; $i++ ) {
 405                                 next( $r );
 406                         }
 407                 }
 408         }
 409
 410         /**
 411          * @return string
 412          */
 413         function lastError() {
 414                 if ( !is_object( $this->mConn ) ) {
 415                         return "Cannot return last error, no db connection";
 416                 }
 417                 $e = $this->mConn->errorInfo();
 418
 419                 return isset( $e[2] ) ? $e[2] : '';
 420         }
 421
 422         /**
 423          * @return string
 424          */
 425         function lastErrno() {
 426                 if ( !is_object( $this->mConn ) ) {
 427                         return "Cannot return last error, no db connection";
 428                 } else {
 429                         $info = $this->mConn->errorInfo();
 430
 431                         return $info[1];
 432                 }
 433         }
 434
 435         /**
 436          * @return int
 437          */
 438         function affectedRows() {
 439                 return $this->mAffectedRows;
 440         }
 441
 442         /**
 443          * Returns information about an index
 444          * Returns false if the index does not exist
 445          * - if errors are explicitly ignored, returns NULL on failure
 446          *
 447          * @return array
 448          */
 449         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 450                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 451                 $res = $this->query( $sql, $fname );
 452                 if ( !$res ) {
 453                         return null;
 454                 }
 455                 if ( $res->numRows() == 0 ) {
 456                         return false;
 457                 }
 458                 $info = array();
 459                 foreach ( $res as $row ) {
 460                         $info[] = $row->name;
 461                 }
 462
 463                 return $info;
 464         }
 465
 466         /**
 467          * @param $table
 468          * @param $index
 469          * @param $fname string
 470          * @return bool|null
 471          */
 472         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 473                 $row = $this->selectRow( 'sqlite_master', '*',
 474                         array(
 475                                 'type' => 'index',
 476                                 'name' => $this->indexName( $index ),
 477                         ), $fname );
 478                 if ( !$row || !isset( $row->sql ) ) {
 479                         return null;
 480                 }
 481
 482                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 483                 $indexPos = strpos( $row->sql, 'INDEX' );
 484                 if ( $indexPos === false ) {
 485                         return null;
 486                 }
 487                 $firstPart = substr( $row->sql, 0, $indexPos );
 488                 $options = explode( ' ', $firstPart );
 489
 490                 return in_array( 'UNIQUE', $options );
 491         }
 492
 493         /**
 494          * Filter the options used in SELECT statements
 495          *
 496          * @param $options array
 497          *
 498          * @return array
 499          */
 500         function makeSelectOptions( $options ) {
 501                 foreach ( $options as $k => $v ) {
 502                         if ( is_numeric( $k ) && ( $v == 'FOR UPDATE' || $v == 'LOCK IN SHARE MODE' ) ) {
 503                                 $options[$k] = '';
 504                         }
 505                 }
 506
 507                 return parent::makeSelectOptions( $options );
 508         }
 509
 510         /**
 511          * @param $options array
 512          * @return string
 513          */
 514         function makeUpdateOptions( $options ) {
 515                 $options = self::fixIgnore( $options );
 516
 517                 return parent::makeUpdateOptions( $options );
 518         }
 519
 520         /**
 521          * @param $options array
 522          * @return array
 523          */
 524         static function fixIgnore( $options ) {
 525                 # SQLite uses OR IGNORE not just IGNORE
 526                 foreach ( $options as $k => $v ) {
 527                         if ( $v == 'IGNORE' ) {
 528                                 $options[$k] = 'OR IGNORE';
 529                         }
 530                 }
 531
 532                 return $options;
 533         }
 534
 535         /**
 536          * @param $options array
 537          * @return string
 538          */
 539         function makeInsertOptions( $options ) {
 540                 $options = self::fixIgnore( $options );
 541
 542                 return parent::makeInsertOptions( $options );
 543         }
 544
 545         /**
 546          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 547          * @return bool
 548          */
 549         function insert( $table, $a, $fname = __METHOD__, $options = array() ) {
 550                 if ( !count( $a ) ) {
 551                         return true;
 552                 }
 553
 554                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 555                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 556                         $ret = true;
 557                         foreach ( $a as $v ) {
 558                                 if ( !parent::insert( $table, $v, "$fname/multi-row", $options ) ) {
 559                                         $ret = false;
 560                                 }
 561                         }
 562                 } else {
 563                         $ret = parent::insert( $table, $a, "$fname/single-row", $options );
 564                 }
 565
 566                 return $ret;
 567         }
 568
 569         /**
 570          * @param $table
 571          * @param $uniqueIndexes
 572          * @param $rows
 573          * @param $fname string
 574          * @return bool|ResultWrapper
 575          */
 576         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 577                 if ( !count( $rows ) ) {
 578                         return true;
 579                 }
 580
 581                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 582                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 583                         $ret = true;
 584                         foreach ( $rows as $v ) {
 585                                 if ( !$this->nativeReplace( $table, $v, "$fname/multi-row" ) ) {
 586                                         $ret = false;
 587                                 }
 588                         }
 589                 } else {
 590                         $ret = $this->nativeReplace( $table, $rows, "$fname/single-row" );
 591                 }
 592
 593                 return $ret;
 594         }
 595
 596         /**
 597          * Returns the size of a text field, or -1 for "unlimited"
 598          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 599          *
 600          * @return int
 601          */
 602         function textFieldSize( $table, $field ) {
 603                 return -1;
 604         }
 605
 606         /**
 607          * @return bool
 608          */
 609         function unionSupportsOrderAndLimit() {
 610                 return false;
 611         }
 612
 613         /**
 614          * @param $sqls
 615          * @param $all
 616          * @return string
 617          */
 618         function unionQueries( $sqls, $all ) {
 619                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 620
 621                 return implode( $glue, $sqls );
 622         }
 623
 624         /**
 625          * @return bool
 626          */
 627         function wasDeadlock() {
 628                 return $this->lastErrno() == 5; // SQLITE_BUSY
 629         }
 630
 631         /**
 632          * @return bool
 633          */
 634         function wasErrorReissuable() {
 635                 return $this->lastErrno() == 17; // SQLITE_SCHEMA;
 636         }
 637
 638         /**
 639          * @return bool
 640          */
 641         function wasReadOnlyError() {
 642                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 643         }
 644
 645         /**
 646          * @return string wikitext of a link to the server software's web site
 647          */
 648         public function getSoftwareLink() {
 649                 return "[http://sqlite.org/ SQLite]";
 650         }
 651
 652         /**
 653          * @return string Version information from the database
 654          */
 655         function getServerVersion() {
 656                 $ver = $this->mConn->getAttribute( PDO::ATTR_SERVER_VERSION );
 657
 658                 return $ver;
 659         }
 660
 661         /**
 662          * @return string User-friendly database information
 663          */
 664         public function getServerInfo() {
 665                 return wfMessage( self::getFulltextSearchModule()
 666                         ? 'sqlite-has-fts'
 667                         : 'sqlite-no-fts', $this->getServerVersion() )->text();
 668         }
 669
 670         /**
 671          * Get information about a given field
 672          * Returns false if the field does not exist.
 673          *
 674          * @param $table string
 675          * @param $field string
 676          * @return SQLiteField|bool False on failure
 677          */
 678         function fieldInfo( $table, $field ) {
 679                 $tableName = $this->tableName( $table );
 680                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 681                 $res = $this->query( $sql, __METHOD__ );
 682                 foreach ( $res as $row ) {
 683                         if ( $row->name == $field ) {
 684                                 return new SQLiteField( $row, $tableName );
 685                         }
 686                 }
 687
 688                 return false;
 689         }
 690
 691         protected function doBegin( $fname = '' ) {
 692                 if ( $this->mTrxLevel == 1 ) {
 693                         $this->commit( __METHOD__ );
 694                 }
 695                 try {
 696                         $this->mConn->beginTransaction();
 697                 } catch ( PDOException $e ) {
 698                         throw new DBUnexpectedError( $this, 'Error in BEGIN query: ' . $e->getMessage() );
 699                 }
 700                 $this->mTrxLevel = 1;
 701         }
 702
 703         protected function doCommit( $fname = '' ) {
 704                 if ( $this->mTrxLevel == 0 ) {
 705                         return;
 706                 }
 707                 try {
 708                         $this->mConn->commit();
 709                 } catch ( PDOException $e ) {
 710                         throw new DBUnexpectedError( $this, 'Error in COMMIT query: ' . $e->getMessage() );
 711                 }
 712                 $this->mTrxLevel = 0;
 713         }
 714
 715         protected function doRollback( $fname = '' ) {
 716                 if ( $this->mTrxLevel == 0 ) {
 717                         return;
 718                 }
 719                 $this->mConn->rollBack();
 720                 $this->mTrxLevel = 0;
 721         }
 722
 723         /**
 724          * @param $s string
 725          * @return string
 726          */
 727         function strencode( $s ) {
 728                 return substr( $this->addQuotes( $s ), 1, -1 );
 729         }
 730
 731         /**
 732          * @param $b
 733          * @return Blob
 734          */
 735         function encodeBlob( $b ) {
 736                 return new Blob( $b );
 737         }
 738
 739         /**
 740          * @param $b Blob|string
 741          * @return string
 742          */
 743         function decodeBlob( $b ) {
 744                 if ( $b instanceof Blob ) {
 745                         $b = $b->fetch();
 746                 }
 747
 748                 return $b;
 749         }
 750
 751         /**
 752          * @param $s Blob|string
 753          * @return string
 754          */
 755         function addQuotes( $s ) {
 756                 if ( $s instanceof Blob ) {
 757                         return "x'" . bin2hex( $s->fetch() ) . "'";
 758                 } elseif ( is_bool( $s ) ) {
 759                         return (int)$s;
 760                 } elseif ( strpos( $s, "\0" ) !== false ) {
 761                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 762                         // This is a known limitation of SQLite's mprintf function which PDO should work around,
 763                         // but doesn't. I have reported this to php.net as bug #63419:
 764                         // https://bugs.php.net/bug.php?id=63419
 765                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 766                         // https://bugs.php.net/bug.php?id=62361
 767                         return "x'" . bin2hex( $s ) . "'";
 768                 } else {
 769                         return $this->mConn->quote( $s );
 770                 }
 771         }
 772
 773         /**
 774          * @return string
 775          */
 776         function buildLike() {
 777                 $params = func_get_args();
 778                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
 779                         $params = $params[0];
 780                 }
 781
 782                 return parent::buildLike( $params ) . "ESCAPE '\' ";
 783         }
 784
 785         /**
 786          * @return string
 787          */
 788         public function getSearchEngine() {
 789                 return "SearchSqlite";
 790         }
 791
 792         /**
 793          * No-op version of deadlockLoop
 794          * @return mixed
 795          */
 796         public function deadlockLoop( /*...*/ ) {
 797                 $args = func_get_args();
 798                 $function = array_shift( $args );
 799
 800                 return call_user_func_array( $function, $args );
 801         }
 802
 803         /**
 804          * @param $s string
 805          * @return string
 806          */
 807         protected function replaceVars( $s ) {
 808                 $s = parent::replaceVars( $s );
 809                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 810                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 811
 812                         // binary/varbinary column type -> blob
 813                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 814                         // no such thing as unsigned
 815                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 816                         // INT -> INTEGER
 817                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 818                         // floating point types -> REAL
 819                         $s = preg_replace(
 820                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 821                                 'REAL',
 822                                 $s
 823                         );
 824                         // varchar -> TEXT
 825                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 826                         // TEXT normalization
 827                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 828                         // BLOB normalization
 829                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 830                         // BOOL -> INTEGER
 831                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 832                         // DATETIME -> TEXT
 833                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 834                         // No ENUM type
 835                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 836                         // binary collation type -> nothing
 837                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 838                         // auto_increment -> autoincrement
 839                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 840                         // No explicit options
 841                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 842                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 843                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 844                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 845                         // No truncated indexes
 846                         $s = preg_replace( '/\(\d+\)/', '', $s );
 847                         // No FULLTEXT
 848                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 849                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 850                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 851                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 852                 }
 853
 854                 return $s;
 855         }
 856
 857         /**
 858          * Build a concatenation list to feed into a SQL query
 859          *
 860          * @param $stringList array
 861          *
 862          * @return string
 863          */
 864         function buildConcat( $stringList ) {
 865                 return '(' . implode( ') || (', $stringList ) . ')';
 866         }
 867
 868         public function buildGroupConcatField(
 869                 $delim, $table, $field, $conds = '', $join_conds = array()
 870         ) {
 871                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
 872
 873                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
 874         }
 875
 876         /**
 877          * @throws MWException
 878          * @param $oldName
 879          * @param $newName
 880          * @param $temporary bool
 881          * @param $fname string
 882          * @return bool|ResultWrapper
 883          */
 884         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 885                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
 886                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
 887                 $obj = $this->fetchObject( $res );
 888                 if ( !$obj ) {
 889                         throw new MWException( "Couldn't retrieve structure for table $oldName" );
 890                 }
 891                 $sql = $obj->sql;
 892                 $sql = preg_replace(
 893                         '/(?<=\W)"?' . preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ) ) . '"?(?=\W)/',
 894                         $this->addIdentifierQuotes( $newName ),
 895                         $sql,
 896                         1
 897                 );
 898                 if ( $temporary ) {
 899                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
 900                                 wfDebug( "Table $oldName is virtual, can't create a temporary duplicate.\n" );
 901                         } else {
 902                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
 903                         }
 904                 }
 905
 906                 return $this->query( $sql, $fname );
 907         }
 908
 909         /**
 910          * List all tables on the database
 911          *
 912          * @param string $prefix Only show tables with this prefix, e.g. mw_
 913          * @param string $fname calling function name
 914          *
 915          * @return array
 916          */
 917         function listTables( $prefix = null, $fname = __METHOD__ ) {
 918                 $result = $this->select(
 919                         'sqlite_master',
 920                         'name',
 921                         "type='table'"
 922                 );
 923
 924                 $endArray = array();
 925
 926                 foreach ( $result as $table ) {
 927                         $vars = get_object_vars( $table );
 928                         $table = array_pop( $vars );
 929
 930                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
 931                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
 932                                         $endArray[] = $table;
 933                                 }
 934                         }
 935                 }
 936
 937                 return $endArray;
 938         }
 939 } // end DatabaseSqlite class
 940
 941 /**
 942  * This class allows simple acccess to a SQLite database independently from main database settings
 943  * @ingroup Database
 944  */
 945 class DatabaseSqliteStandalone extends DatabaseSqlite {
 946         public function __construct( $fileName, $flags = 0 ) {
 947                 $this->mFlags = $flags;
 948                 $this->tablePrefix( null );
 949                 $this->openFile( $fileName );
 950         }
 951 }
 952
 953 /**
 954  * @ingroup Database
 955  */
 956 class SQLiteField implements Field {
 957         private $info, $tableName;
 958
 959         function __construct( $info, $tableName ) {
 960                 $this->info = $info;
 961                 $this->tableName = $tableName;
 962         }
 963
 964         function name() {
 965                 return $this->info->name;
 966         }
 967
 968         function tableName() {
 969                 return $this->tableName;
 970         }
 971
 972         function defaultValue() {
 973                 if ( is_string( $this->info->dflt_value ) ) {
 974                         // Typically quoted
 975                         if ( preg_match( '/^\'(.*)\'$', $this->info->dflt_value ) ) {
 976                                 return str_replace( "''", "'", $this->info->dflt_value );
 977                         }
 978                 }
 979
 980                 return $this->info->dflt_value;
 981         }
 982
 983         /**
 984          * @return bool
 985          */
 986         function isNullable() {
 987                 return !$this->info->notnull;
 988         }
 989
 990         function type() {
 991                 return $this->info->type;
 992         }
 993 } // end SQLiteField