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// Copyright (C) 2015-2018 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef HOST_DATA_SOURCE_FACTORY_H
#define HOST_DATA_SOURCE_FACTORY_H
#include <dhcpsrv/base_host_data_source.h>
#include <dhcpsrv/database_connection.h>
#include <exceptions/exceptions.h>
#include <boost/scoped_ptr.hpp>
#include <boost/function.hpp>
#include <string>
#include <vector>
#include <map>
namespace isc {
namespace dhcp {
/// @brief No host data source instance exception
///
/// Thrown if an attempt is made to get a reference to the current
/// host data source instance and none is currently available.
class NoHostDataSourceManager : public Exception {
public:
NoHostDataSourceManager(const char* file, size_t line, const char* what) :
isc::Exception(file, line, what) {}
};
/// @brief Host Data Source Factory
///
/// This class comprises nothing but static methods used to create a host data
/// source object. It analyzes the database information passed to the creation
/// function and instantiates an appropriate host data source object based on
/// the type requested.
///
/// Strictly speaking these functions could be stand-alone functions. However,
/// it is convenient to encapsulate them in a class for naming purposes.
class HostDataSourceFactory {
public:
/// @brief Create and add an instance of a host data source.
///
/// Each database backend has its own host data source type. This static
/// method adds an object of the appropriate type to a list of
/// host data sources.
///
/// dbaccess is a generic way of passing parameters. Parameters are passed
/// in the "name=value" format, separated by spaces. The data MUST include
/// a keyword/value pair of the form "type=dbtype" giving the database
/// type, e.q. "mysql" or "sqlite3".
///
/// @param sources host data source list (new backend will be added here)
/// @param dbaccess Database access parameters. These are in the form of
/// "keyword=value" pairs, separated by spaces. They are backend-
/// -end specific, although must include the "type" keyword which
/// gives the backend in use.
///
/// @throw isc::InvalidParameter dbaccess string does not contain the "type"
/// keyword.
/// @throw isc::dhcp::InvalidType The "type" keyword in dbaccess does not
/// identify a supported backend.
static void add(HostDataSourceList& sources, const std::string& dbaccess);
/// @brief Delete a host data source.
///
/// Delete the first instance of a host data source of the given type.
/// This should have the effect of closing the database connection.
///
/// @param sources host data source list.
/// @param db_type database backend type.
/// @return true when found and removed, false when not found.
static bool del(HostDataSourceList& sources, const std::string& db_type);
/// @brief Type of host data source factory
///
/// A factory takes a parameter map and returns a pointer to a host
/// data source. In case of failure it must throw and not return NULL.
typedef boost::function<HostDataSourcePtr (const DatabaseConnection::ParameterMap&)> Factory;
/// @brief Register a host data source factory
///
/// Associate the factory to a database type in the map.
/// The no_log is to avoid logging before the logger is initialized
/// as when called at global object initialization.
///
/// @param db_type database type
/// @param factory host data source factory
/// @param no_log do not log (default false)
/// @return true if the factory was successfully added to the map, false
/// if it already exists.
static bool registerFactory(const std::string& db_type,
const Factory& factory, bool no_log = false);
/// @brief Deregister a host data source factory
///
/// Disassociate the factory to a database type in the map.
/// The no_log is to avoid logging during global object deinitialization.
///
/// @param db_type database type
/// @param no_log do not log (default false)
/// @return true if the factory was successfully removed from the map,
/// false if it was not found.
static bool deregisterFactory(const std::string& db_type,
bool no_log = false);
/// @brief Prints out all registered backends.
///
/// We need a dedicated method for this, because we sometimes can't log
/// the backend type when doing early initialization for backends
/// initialized statically.
static void printRegistered();
private:
/// @brief Factory map
static std::map<std::string, Factory> map_;
};
}; // end of isc::dhcp namespace
}; // end of isc namespace
#endif
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