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[mediawiki.git] / includes / libs / rdbms / database / DatabaseSqlite.php

<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */
namespace Wikimedia\Rdbms;

use FSLockManager;
use LockManager;
use NullLockManager;
use PDO;
use PDOException;
use PDOStatement;
use RuntimeException;
use Wikimedia\Rdbms\Platform\SqlitePlatform;
use Wikimedia\Rdbms\Platform\SQLPlatform;
use Wikimedia\Rdbms\Replication\ReplicationReporter;

/**
 * This is the SQLite database abstraction layer.
 *
 * See docs/sqlite.txt for development notes about MediaWiki's sqlite schema.
 *
 * @ingroup Database
 */
class DatabaseSqlite extends Database {
        /** @var string|null Directory for SQLite database files listed under their DB name */
        protected $dbDir;
        /** @var string|null Explicit path for the SQLite database file */
        protected $dbPath;
        /** @var string Transaction mode */
        protected $trxMode;

        /** @var PDO|null */
        protected $conn;

        /** @var LockManager|null (hopefully on the same server as the DB) */
        protected $lockMgr;

        /** @var string|null */
        private $version;

        /** @var array List of shared database already attached to this connection */
        private $sessionAttachedDbs = [];

        /** @var string[] See https://www.sqlite.org/lang_transaction.html */
        private const VALID_TRX_MODES = [ '', 'DEFERRED', 'IMMEDIATE', 'EXCLUSIVE' ];

        /** @var string[][] */
        private const VALID_PRAGMAS = [
                // Optimizations or requirements regarding fsync() usage
                'synchronous' => [ 'EXTRA', 'FULL', 'NORMAL', 'OFF' ],
                // Optimizations for TEMPORARY tables
                'temp_store' => [ 'FILE', 'MEMORY' ],
                // Optimizations for disk use and page cache
                'mmap_size' => 'integer',
                // How many DB pages to keep in memory
                'cache_size' => 'integer',
        ];

        /** @var SQLPlatform */
        protected $platform;

        /**
         * Additional params include:
         *   - dbDirectory : directory containing the DB and the lock file directory
         *   - dbFilePath  : use this to force the path of the DB file
         *   - trxMode     : one of (deferred, immediate, exclusive)
         * @param array $params
         */
        public function __construct( array $params ) {
                if ( isset( $params['dbFilePath'] ) ) {
                        $this->dbPath = $params['dbFilePath'];
                        if ( !isset( $params['dbname'] ) || $params['dbname'] === '' ) {
                                $params['dbname'] = self::generateDatabaseName( $this->dbPath );
                        }
                } elseif ( isset( $params['dbDirectory'] ) ) {
                        $this->dbDir = $params['dbDirectory'];
                }

                parent::__construct( $params );

                $this->trxMode = strtoupper( $params['trxMode'] ?? '' );

                $this->lockMgr = $this->makeLockManager();
                $this->platform = new SqlitePlatform(
                        $this,
                        $this->logger,
                        $this->currentDomain,
                        $this->errorLogger
                );
                $this->replicationReporter = new ReplicationReporter(
                        $params['topologyRole'],
                        $this->logger,
                        $params['srvCache']
                );
        }

        public static function getAttributes() {
                return [
                        self::ATTR_DB_IS_FILE => true,
                        self::ATTR_DB_LEVEL_LOCKING => true
                ];
        }

        /**
         * @param string $filename
         * @param array $p Options map; supports:
         *   - flags       : (same as __construct counterpart)
         *   - trxMode     : (same as __construct counterpart)
         *   - dbDirectory : (same as __construct counterpart)
         * @return DatabaseSqlite
         * @since 1.25
         */
        public static function newStandaloneInstance( $filename, array $p = [] ) {
                $p['dbFilePath'] = $filename;
                $p['schema'] = null;
                $p['tablePrefix'] = '';
                /** @var DatabaseSqlite $db */
                $db = ( new DatabaseFactory() )->create( 'sqlite', $p );
                '@phan-var DatabaseSqlite $db';

                return $db;
        }

        /**
         * @return string
         */
        public function getType() {
                return 'sqlite';
        }

        protected function open( $server, $user, $password, $db, $schema, $tablePrefix ) {
                $this->close( __METHOD__ );

                // Note that for SQLite, $server, $user, and $pass are ignored

                if ( $schema !== null ) {
                        throw $this->newExceptionAfterConnectError( "Got schema '$schema'; not supported." );
                }

                if ( $this->dbPath !== null ) {
                        $path = $this->dbPath;
                } elseif ( $this->dbDir !== null ) {
                        $path = self::generateFileName( $this->dbDir, $db );
                } else {
                        throw $this->newExceptionAfterConnectError( "DB path or directory required" );
                }

                // Check if the database file already exists but is non-readable
                if ( !self::isProcessMemoryPath( $path ) && is_file( $path ) && !is_readable( $path ) ) {
                        throw $this->newExceptionAfterConnectError( 'SQLite database file is not readable' );
                } elseif ( !in_array( $this->trxMode, self::VALID_TRX_MODES, true ) ) {
                        throw $this->newExceptionAfterConnectError( "Got mode '{$this->trxMode}' for BEGIN" );
                }

                $attributes = [
                        PDO::ATTR_ERRMODE => PDO::ERRMODE_SILENT,
                        // Starting with PHP 8.1, The SQLite PDO returns proper types instead
                        // of strings or null for everything. We cast every non-null value to
                        // string to restore the old behavior.
                        PDO::ATTR_STRINGIFY_FETCHES => true
                ];
                if ( $this->getFlag( self::DBO_PERSISTENT ) ) {
                        // Persistent connections can avoid some schema index reading overhead.
                        // On the other hand, they can cause horrible contention with DBO_TRX.
                        if ( $this->getFlag( self::DBO_TRX ) || $this->getFlag( self::DBO_DEFAULT ) ) {
                                $this->logger->warning(
                                        __METHOD__ . ": ignoring DBO_PERSISTENT due to DBO_TRX or DBO_DEFAULT",
                                        $this->getLogContext()
                                );
                        } else {
                                $attributes[PDO::ATTR_PERSISTENT] = true;
                        }
                }

                try {
                        // Open the database file, creating it if it does not yet exist
                        $this->conn = new PDO( "sqlite:$path", null, null, $attributes );
                } catch ( PDOException $e ) {
                        throw $this->newExceptionAfterConnectError( $e->getMessage() );
                }

                $this->currentDomain = new DatabaseDomain( $db, null, $tablePrefix );
                $this->platform->setCurrentDomain( $this->currentDomain );

                try {
                        // Enforce LIKE to be case sensitive, just like MySQL
                        $query = new Query(
                                'PRAGMA case_sensitive_like = 1',
                                self::QUERY_CHANGE_TRX | self::QUERY_NO_RETRY,
                                'PRAGMA'
                        );
                        $this->query( $query, __METHOD__ );
                        // Set any connection-level custom PRAGMA options
                        $pragmas = array_intersect_key( $this->connectionVariables, self::VALID_PRAGMAS );
                        $pragmas += $this->getDefaultPragmas();
                        foreach ( $pragmas as $name => $value ) {
                                $allowed = self::VALID_PRAGMAS[$name];
                                if (
                                        ( is_array( $allowed ) && in_array( $value, $allowed, true ) ) ||
                                        ( is_string( $allowed ) && gettype( $value ) === $allowed )
                                ) {
                                        $query = new Query(
                                                "PRAGMA $name = $value",
                                                self::QUERY_CHANGE_TRX | self::QUERY_NO_RETRY,
                                                'PRAGMA',
                                                null,
                                                "PRAGMA $name = '?'"
                                        );
                                        $this->query( $query, __METHOD__ );
                                }
                        }
                        $this->attachDatabasesFromTableAliases();
                } catch ( RuntimeException $e ) {
                        throw $this->newExceptionAfterConnectError( $e->getMessage() );
                }
        }

        /**
         * @return array Map of (name => value) for default values to set via PRAGMA
         */
        private function getDefaultPragmas() {
                $variables = [];

                if ( !$this->cliMode ) {
                        $variables['temp_store'] = 'MEMORY';
                }

                return $variables;
        }

        /**
         * @return string|null SQLite DB file path
         * @throws DBUnexpectedError
         * @since 1.25
         */
        public function getDbFilePath() {
                return $this->dbPath ?? self::generateFileName( $this->dbDir, $this->getDBname() );
        }

        /**
         * @return string|null Lock file directory
         */
        public function getLockFileDirectory() {
                if ( $this->dbPath !== null && !self::isProcessMemoryPath( $this->dbPath ) ) {
                        return dirname( $this->dbPath ) . '/locks';
                } elseif ( $this->dbDir !== null && !self::isProcessMemoryPath( $this->dbDir ) ) {
                        return $this->dbDir . '/locks';
                }

                return null;
        }

        /**
         * Initialize/reset the LockManager instance
         *
         * @return LockManager
         */
        private function makeLockManager(): LockManager {
                $lockDirectory = $this->getLockFileDirectory();
                if ( $lockDirectory !== null ) {
                        return new FSLockManager( [
                                'domain' => $this->getDomainID(),
                                'lockDirectory' => $lockDirectory,
                        ] );
                } else {
                        return new NullLockManager( [ 'domain' => $this->getDomainID() ] );
                }
        }

        /**
         * Does not actually close the connection, just destroys the reference for GC to do its work
         * @return bool
         */
        protected function closeConnection() {
                $this->conn = null;
                // Release all locks, via FSLockManager::__destruct, as the base class expects
                $this->lockMgr = null;

                return true;
        }

        /**
         * Generates a database file name. Explicitly public for installer.
         * @param string $dir Directory where database resides
         * @param string|null $dbName Database name (or null from Database::factory, validated here)
         * @return string
         * @throws DBUnexpectedError
         */
        public static function generateFileName( $dir, $dbName ) {
                if ( $dir == '' ) {
                        throw new DBUnexpectedError( null, __CLASS__ . ": no DB directory specified" );
                } elseif ( self::isProcessMemoryPath( $dir ) ) {
                        throw new DBUnexpectedError(
                                null,
                                __CLASS__ . ": cannot use process memory directory '$dir'"
                        );
                } elseif ( !strlen( $dbName ) ) {
                        throw new DBUnexpectedError( null, __CLASS__ . ": no DB name specified" );
                }

                return "$dir/$dbName.sqlite";
        }

        /**
         * @param string $path
         * @return string
         */
        private static function generateDatabaseName( $path ) {
                if ( preg_match( '/^(:memory:$|file::memory:)/', $path ) ) {
                        // E.g. "file::memory:?cache=shared" => ":memory":
                        return ':memory:';
                } elseif ( preg_match( '/^file::([^?]+)\?mode=memory(&|$)/', $path, $m ) ) {
                        // E.g. "file:memdb1?mode=memory" => ":memdb1:"
                        return ":{$m[1]}:";
                } else {
                        // E.g. "/home/.../some_db.sqlite3" => "some_db"
                        return preg_replace( '/\.sqlite\d?$/', '', basename( $path ) );
                }
        }

        /**
         * @param string $path
         * @return bool
         */
        private static function isProcessMemoryPath( $path ) {
                return preg_match( '/^(:memory:$|file:(:memory:|[^?]+\?mode=memory(&|$)))/', $path );
        }

        /**
         * Returns version of currently supported SQLite fulltext search module or false if none present.
         * @return string|false
         */
        public static function getFulltextSearchModule() {
                static $cachedResult = null;
                if ( $cachedResult !== null ) {
                        return $cachedResult;
                }
                $cachedResult = false;
                $table = 'dummy_search_test';

                $db = self::newStandaloneInstance( ':memory:' );
                if ( $db->query(
                        "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)",
                        __METHOD__,
                        IDatabase::QUERY_SILENCE_ERRORS
                ) ) {
                        $cachedResult = 'FTS3';
                }
                $db->close( __METHOD__ );

                return $cachedResult;
        }

        /**
         * Attaches external database to the connection handle
         *
         * @see https://sqlite.org/lang_attach.html
         *
         * @param string $name Database name to be used in queries like
         *   SELECT foo FROM dbname.table
         * @param bool|string $file Database file name. If omitted, will be generated
         *   using $name and configured data directory
         * @param string $fname Calling function name @phan-mandatory-param
         * @return IResultWrapper
         */
        public function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
                $file = is_string( $file ) ? $file : self::generateFileName( $this->dbDir, $name );
                $encFile = $this->addQuotes( $file );
                $query = new Query(
                        "ATTACH DATABASE $encFile AS $name",
                        self::QUERY_CHANGE_TRX,
                        'ATTACH'
                );
                return $this->query( $query, $fname );
        }

        protected function doSingleStatementQuery( string $sql ): QueryStatus {
                $res = $this->getBindingHandle()->query( $sql );
                // Note that rowCount() returns 0 for SELECT for SQLite
                return new QueryStatus(
                        $res instanceof PDOStatement ? new SqliteResultWrapper( $res ) : $res,
                        $res ? $res->rowCount() : 0,
                        $this->lastError(),
                        $this->lastErrno()
                );
        }

        protected function doSelectDomain( DatabaseDomain $domain ) {
                if ( $domain->getSchema() !== null ) {
                        throw new DBExpectedError(
                                $this,
                                __CLASS__ . ": domain '{$domain->getId()}' has a schema component"
                        );
                }

                $database = $domain->getDatabase();
                // A null database means "don't care" so leave it as is and update the table prefix
                if ( $database === null ) {
                        $this->currentDomain = new DatabaseDomain(
                                $this->currentDomain->getDatabase(),
                                null,
                                $domain->getTablePrefix()
                        );
                        $this->platform->setCurrentDomain( $this->currentDomain );

                        return true;
                }

                if ( $database !== $this->getDBname() ) {
                        throw new DBExpectedError(
                                $this,
                                __CLASS__ . ": cannot change database (got '$database')"
                        );
                }

                // Update that domain fields on success (no exception thrown)
                $this->currentDomain = $domain;
                $this->platform->setCurrentDomain( $domain );

                return true;
        }

        protected function lastInsertId() {
                // PDO::lastInsertId yields a string :(
                return (int)$this->getBindingHandle()->lastInsertId();
        }

        /**
         * @return string
         */
        public function lastError() {
                if ( is_object( $this->conn ) ) {
                        $e = $this->conn->errorInfo();

                        return $e[2] ?? $this->lastConnectError;
                }

                return 'No database connection';
        }

        /**
         * @return int
         */
        public function lastErrno() {
                if ( is_object( $this->conn ) ) {
                        $info = $this->conn->errorInfo();

                        if ( isset( $info[1] ) ) {
                                return $info[1];
                        }
                }

                return 0;
        }

        public function tableExists( $table, $fname = __METHOD__ ) {
                [ $db, $pt ] = $this->platform->getDatabaseAndTableIdentifier( $table );
                if ( isset( $this->sessionTempTables[$db][$pt] ) ) {
                        return true; // already known to exist
                }

                $encTable = $this->addQuotes( $pt );
                $query = new Query(
                        "SELECT 1 FROM sqlite_master WHERE type='table' AND name=$encTable",
                        self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                        'SELECT'
                );
                $res = $this->query( $query, __METHOD__ );

                return (bool)$res->numRows();
        }

        public function indexInfo( $table, $index, $fname = __METHOD__ ) {
                $indexName = $this->platform->indexName( $index );
                $components = $this->platform->qualifiedTableComponents( $table );
                $tableRaw = end( $components );
                $query = new Query(
                        'PRAGMA index_list(' . $this->addQuotes( $tableRaw ) . ')',
                        self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                        'PRAGMA'
                );
                $res = $this->query( $query, $fname );

                foreach ( $res as $row ) {
                        if ( $row->name === $indexName ) {
                                return [ 'unique' => (bool)$row->unique ];
                        }
                }

                return false;
        }

        public function replace( $table, $uniqueKeys, $rows, $fname = __METHOD__ ) {
                $this->platform->normalizeUpsertParams( $uniqueKeys, $rows );
                if ( !$rows ) {
                        return;
                }
                $encTable = $this->tableName( $table );
                [ $sqlColumns, $sqlTuples ] = $this->platform->makeInsertLists( $rows );
                // https://sqlite.org/lang_insert.html
                // Note that any auto-increment columns on conflicting rows will be reassigned
                // due to combined DELETE+INSERT semantics. This will be reflected in insertId().
                $query = new Query(
                        "REPLACE INTO $encTable ($sqlColumns) VALUES $sqlTuples",
                        self::QUERY_CHANGE_ROWS,
                        'REPLACE',
                        $table
                );
                $this->query( $query, $fname );
        }

        protected function isConnectionError( $errno ) {
                return $errno == 17; // SQLITE_SCHEMA;
        }

        protected function isKnownStatementRollbackError( $errno ) {
                // ON CONFLICT ROLLBACK clauses make it so that SQLITE_CONSTRAINT error is
                // ambiguous with regard to whether it implies a ROLLBACK or an ABORT happened.
                // https://sqlite.org/lang_createtable.html#uniqueconst
                // https://sqlite.org/lang_conflict.html
                return false;
        }

        public function serverIsReadOnly() {
                $this->assertHasConnectionHandle();

                $path = $this->getDbFilePath();

                return ( !self::isProcessMemoryPath( $path ) && !is_writable( $path ) );
        }

        /**
         * @return string Wikitext of a link to the server software's web site
         */
        public function getSoftwareLink() {
                return "[{{int:version-db-sqlite-url}} SQLite]";
        }

        /**
         * @return string Version information from the database
         */
        public function getServerVersion() {
                if ( $this->version === null ) {
                        $this->version = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
                }

                return $this->version;
        }

        /**
         * Get information about a given field
         * Returns false if the field does not exist.
         *
         * @param string $table
         * @param string $field
         * @return SQLiteField|false False on failure
         */
        public function fieldInfo( $table, $field ) {
                $components = $this->platform->qualifiedTableComponents( $table );
                $tableRaw = end( $components );
                $query = new Query(
                        'PRAGMA table_info(' . $this->addQuotes( $tableRaw ) . ')',
                        self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                        'PRAGMA'
                );
                $res = $this->query( $query, __METHOD__ );
                foreach ( $res as $row ) {
                        if ( $row->name == $field ) {
                                return new SQLiteField( $row, $tableRaw );
                        }
                }

                return false;
        }

        protected function doBegin( $fname = '' ) {
                if ( $this->trxMode != '' ) {
                        $sql = "BEGIN {$this->trxMode}";
                } else {
                        $sql = 'BEGIN';
                }
                $query = new Query( $sql, self::QUERY_CHANGE_TRX, 'BEGIN' );
                $this->query( $query, $fname );
        }

        /**
         * @param string $s
         * @return string
         */
        public function strencode( $s ) {
                return substr( $this->addQuotes( $s ), 1, -1 );
        }

        /**
         * @param string $b
         * @return Blob
         */
        public function encodeBlob( $b ) {
                return new Blob( $b );
        }

        /**
         * @param Blob|string $b
         * @return string
         */
        public function decodeBlob( $b ) {
                if ( $b instanceof Blob ) {
                        $b = $b->fetch();
                }
                if ( $b === null ) {
                        // An empty blob is decoded as null in PHP before PHP 8.1.
                        // It was probably fixed as a side-effect of caa710037e663fd78f67533b29611183090068b2
                        $b = '';
                }

                return $b;
        }

        public function addQuotes( $s ) {
                if ( $s instanceof RawSQLValue ) {
                        return $s->toSql();
                }
                if ( $s instanceof Blob ) {
                        return "x'" . bin2hex( $s->fetch() ) . "'";
                } elseif ( is_bool( $s ) ) {
                        return (string)(int)$s;
                } elseif ( is_int( $s ) ) {
                        return (string)$s;
                } elseif ( strpos( (string)$s, "\0" ) !== false ) {
                        // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
                        // This is a known limitation of SQLite's mprintf function which PDO
                        // should work around, but doesn't. I have reported this to php.net as bug #63419:
                        // https://bugs.php.net/bug.php?id=63419
                        // There was already a similar report for SQLite3::escapeString, bug #62361:
                        // https://bugs.php.net/bug.php?id=62361
                        // There is an additional bug regarding sorting this data after insert
                        // on older versions of sqlite shipped with ubuntu 12.04
                        // https://phabricator.wikimedia.org/T74367
                        $this->logger->debug(
                                __FUNCTION__ .
                                ': Quoting value containing null byte. ' .
                                'For consistency all binary data should have been ' .
                                'first processed with self::encodeBlob()'
                        );
                        return "x'" . bin2hex( (string)$s ) . "'";
                } else {
                        return $this->getBindingHandle()->quote( (string)$s );
                }
        }

        public function doLockIsFree( string $lockName, string $method ) {
                // Only locks by this thread will be checked
                return true;
        }

        public function doLock( string $lockName, string $method, int $timeout ) {
                $status = $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout );
                if (
                        $this->lockMgr instanceof FSLockManager &&
                        $status->hasMessage( 'lockmanager-fail-openlock' )
                ) {
                        throw new DBError( $this, "Cannot create directory \"{$this->getLockFileDirectory()}\"" );
                }

                return $status->isOK() ? microtime( true ) : null;
        }

        public function doUnlock( string $lockName, string $method ) {
                return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isGood();
        }

        /**
         * @param string $oldName
         * @param string $newName
         * @param bool $temporary
         * @param string $fname
         * @return bool|IResultWrapper
         * @throws RuntimeException
         */
        public function duplicateTableStructure(
                $oldName, $newName, $temporary = false, $fname = __METHOD__
        ) {
                $query = new Query(
                        "SELECT sql FROM sqlite_master WHERE tbl_name=" .
                        $this->addQuotes( $oldName ) . " AND type='table'",
                        self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                        'SELECT'
                );
                $res = $this->query( $query, $fname );
                $obj = $res->fetchObject();
                if ( !$obj ) {
                        throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
                }
                $sqlCreateTable = $obj->sql;
                $sqlCreateTable = preg_replace(
                        '/(?<=\W)"?' .
                                preg_quote( trim( $this->platform->addIdentifierQuotes( $oldName ), '"' ), '/' ) .
                                '"?(?=\W)/',
                        $this->platform->addIdentifierQuotes( $newName ),
                        $sqlCreateTable,
                        1
                );
                $flags = self::QUERY_CHANGE_SCHEMA | self::QUERY_PSEUDO_PERMANENT;
                if ( $temporary ) {
                        if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sqlCreateTable ) ) {
                                $this->logger->debug(
                                        "Table $oldName is virtual, can't create a temporary duplicate." );
                        } else {
                                $sqlCreateTable = str_replace(
                                        'CREATE TABLE',
                                        'CREATE TEMPORARY TABLE',
                                        $sqlCreateTable
                                );
                        }
                }

                $query = new Query(
                        $sqlCreateTable,
                        $flags,
                        $temporary ? 'CREATE TEMPORARY' : 'CREATE',
                        // Use a dot to avoid double-prefixing in Database::getTempTableWrites()
                        '.' . $newName
                );
                $res = $this->query( $query, $fname );

                $query = new Query(
                        'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')',
                        self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                        'PRAGMA'
                );
                // Take over indexes
                $indexList = $this->query( $query, $fname );
                foreach ( $indexList as $index ) {
                        if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
                                continue;
                        }

                        if ( $index->unique ) {
                                $sqlIndex = 'CREATE UNIQUE INDEX';
                        } else {
                                $sqlIndex = 'CREATE INDEX';
                        }
                        // Try to come up with a new index name, given indexes have database scope in SQLite
                        $indexName = $newName . '_' . $index->name;
                        $sqlIndex .= ' ' . $this->platform->addIdentifierQuotes( $indexName ) .
                                ' ON ' . $this->platform->addIdentifierQuotes( $newName );

                        $query = new Query(
                                'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')',
                                self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                                'PRAGMA'
                        );
                        $indexInfo = $this->query( $query, $fname );
                        $fields = [];
                        foreach ( $indexInfo as $indexInfoRow ) {
                                $fields[$indexInfoRow->seqno] = $this->addQuotes( $indexInfoRow->name );
                        }

                        $sqlIndex .= '(' . implode( ',', $fields ) . ')';

                        $query = new Query(
                                $sqlIndex,
                                self::QUERY_CHANGE_SCHEMA | self::QUERY_PSEUDO_PERMANENT,
                                'CREATE',
                                $newName
                        );
                        $this->query( $query, __METHOD__ );
                }

                return $res;
        }

        /**
         * List all tables on the database
         *
         * @param string|null $prefix Only show tables with this prefix, e.g. mw_
         * @param string $fname Calling function name
         *
         * @return array
         */
        public function listTables( $prefix = null, $fname = __METHOD__ ) {
                $query = new Query(
                        "SELECT name FROM sqlite_master WHERE type = 'table'",
                        self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                        'SELECT'
                );
                $result = $this->query( $query, $fname );

                $endArray = [];

                foreach ( $result as $table ) {
                        $vars = get_object_vars( $table );
                        $table = array_pop( $vars );

                        if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
                                if ( strpos( $table, 'sqlite_' ) !== 0 ) {
                                        $endArray[] = $table;
                                }
                        }
                }

                return $endArray;
        }

        public function truncateTable( $table, $fname = __METHOD__ ) {
                $this->startAtomic( $fname );
                // Use "truncate" optimization; https://www.sqlite.org/lang_delete.html
                $query = new Query(
                        "DELETE FROM " . $this->tableName( $table ),
                        self::QUERY_CHANGE_SCHEMA,
                        'DELETE',
                        $table
                );
                $this->query( $query, $fname );

                $encMasterTable = $this->platform->addIdentifierQuotes( 'sqlite_sequence' );
                $encSequenceName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
                $query = new Query(
                        "DELETE FROM $encMasterTable WHERE name = $encSequenceName",
                        self::QUERY_CHANGE_SCHEMA,
                        'DELETE',
                        'sqlite_sequence'
                );
                $this->query( $query, $fname );

                $this->endAtomic( $fname );
        }

        public function setTableAliases( array $aliases ) {
                parent::setTableAliases( $aliases );
                if ( $this->isOpen() ) {
                        $this->attachDatabasesFromTableAliases();
                }
        }

        /**
         * Issue ATTATCH statements for all unattached foreign DBs in table aliases
         */
        private function attachDatabasesFromTableAliases() {
                foreach ( $this->platform->getTableAliases() as $params ) {
                        if (
                                $params['dbname'] !== $this->getDBname() &&
                                !isset( $this->sessionAttachedDbs[$params['dbname']] )
                        ) {
                                $this->attachDatabase( $params['dbname'], false, __METHOD__ );
                                $this->sessionAttachedDbs[$params['dbname']] = true;
                        }
                }
        }

        public function databasesAreIndependent() {
                return true;
        }

        protected function doHandleSessionLossPreconnect() {
                $this->sessionAttachedDbs = [];
                // Release all locks, via FSLockManager::__destruct, as the base class expects;
                $this->lockMgr = null;
                // Create a new lock manager instance
                $this->lockMgr = $this->makeLockManager();
        }

        protected function doFlushSession( $fname ) {
                // Release all locks, via FSLockManager::__destruct, as the base class expects
                $this->lockMgr = null;
                // Create a new lock manager instance
                $this->lockMgr = $this->makeLockManager();
        }

        /**
         * @return PDO
         */
        protected function getBindingHandle() {
                return parent::getBindingHandle();
        }

        protected function getInsertIdColumnForUpsert( $table ) {
                $components = $this->platform->qualifiedTableComponents( $table );
                $tableRaw = end( $components );
                $query = new Query(
                        'PRAGMA table_info(' . $this->addQuotes( $tableRaw ) . ')',
                        self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE,
                        'PRAGMA'
                );
                $res = $this->query( $query, __METHOD__ );
                foreach ( $res as $row ) {
                        if ( $row->pk && strtolower( $row->type ) === 'integer' ) {
                                return $row->name;
                        }
                }

                return null;
        }
}