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Diffstat (limited to 'src/lib/dhcpsrv/host_data_source_factory.h')
| -rw-r--r-- | src/lib/dhcpsrv/host_data_source_factory.h | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/src/lib/dhcpsrv/host_data_source_factory.h b/src/lib/dhcpsrv/host_data_source_factory.h new file mode 100644 index 0000000..76b2a9d --- /dev/null +++ b/src/lib/dhcpsrv/host_data_source_factory.h @@ -0,0 +1,150 @@ +// Copyright (C) 2015-2021 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 <database/database_connection.h> +#include <dhcpsrv/base_host_data_source.h> +#include <exceptions/exceptions.h> +#include <boost/scoped_ptr.hpp> + +#include <functional> +#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 Delete a host data source. + /// + /// Delete the first instance of a host data source which matches specific + /// parameters. + /// This should have the effect of closing the database connection. + /// + /// @param sources host data source list. + /// @param db_type database backend type. + /// @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. + /// @param if_unusable flag which indicates if the host data source should + /// be deleted only if it is unusable. + /// @return false when not removed because it is not found or because it is + /// still usable (if_unusable is true), true otherwise. + static bool del(HostDataSourceList& sources, const std::string& db_type, + const std::string& dbaccess, bool if_unusable = true); + + /// @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 std::function<HostDataSourcePtr (const db::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 Check if a host data source factory was registered + /// + /// @param db_type database type + /// @return true if a factory was registered for db_type, false if not. + static bool registeredFactory(const std::string& db_type); + + /// @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 |