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/**
* Copyright (C) 2012-2014 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <set>
#include "mongo/base/string_data.h"
#include "mongo/db/namespace_string.h"
#include "mongo/util/concurrency/mutex.h"
#include "mongo/util/string_map.h"
namespace mongo {
class Database;
class OperationContext;
/**
* Registry of opened databases.
*/
class DatabaseHolder {
public:
DatabaseHolder() = default;
/**
* Retrieves an already opened database or returns NULL. Must be called with the database
* locked in at least IS-mode.
*/
Database* get(OperationContext* txn, StringData ns) const;
/**
* Retrieves a database reference if it is already opened, or opens it if it hasn't been
* opened/created yet. Must be called with the database locked in X-mode.
*
* @param justCreated Returns whether the database was newly created (true) or it already
* existed (false). Can be NULL if this information is not necessary.
*/
Database* openDb(OperationContext* txn, StringData ns, bool* justCreated = NULL);
/**
* Closes the specified database. Must be called with the database locked in X-mode.
*/
void close(OperationContext* txn, StringData ns);
/**
* Closes all opened databases. Must be called with the global lock acquired in X-mode.
*
* @param result Populated with the names of the databases, which were closed.
* @param force Force close even if something underway - use at shutdown
*/
bool closeAll(OperationContext* txn, BSONObjBuilder& result, bool force);
/**
* Retrieves the names of all currently opened databases. Does not require locking, but it
* is not guaranteed that the returned set of names will be still valid unless a global
* lock is held, which would prevent database from disappearing or being created.
*/
void getAllShortNames( std::set<std::string>& all ) const {
stdx::lock_guard<SimpleMutex> lk(_m);
for( DBs::const_iterator j=_dbs.begin(); j!=_dbs.end(); ++j ) {
all.insert( j->first );
}
}
private:
typedef StringMap<Database*> DBs;
mutable SimpleMutex _m;
DBs _dbs;
};
DatabaseHolder& dbHolder();
}
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