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Diffstat (limited to 'src/lib/dhcpsrv/lease_mgr_factory.h')
| -rw-r--r-- | src/lib/dhcpsrv/lease_mgr_factory.h | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/lib/dhcpsrv/lease_mgr_factory.h b/src/lib/dhcpsrv/lease_mgr_factory.h new file mode 100644 index 0000000..69fef85 --- /dev/null +++ b/src/lib/dhcpsrv/lease_mgr_factory.h @@ -0,0 +1,119 @@ +// Copyright (C) 2012-2023 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 LEASE_MGR_FACTORY_H +#define LEASE_MGR_FACTORY_H + +#include <database/database_connection.h> +#include <dhcpsrv/tracking_lease_mgr.h> +#include <exceptions/exceptions.h> + +#include <boost/scoped_ptr.hpp> + +#include <string> + +namespace isc { +namespace dhcp { + + +/// @brief No lease manager exception +/// +/// Thrown if an attempt is made to get a reference to the current lease +/// manager and none is currently available. +class NoLeaseManager : public Exception { +public: + NoLeaseManager(const char* file, size_t line, const char* what) : + isc::Exception(file, line, what) {} +}; + +/// @brief Lease Manager Factory +/// +/// This class comprises nothing but static methods used to create a lease +/// manager. It analyzes the database information passed to the creation +/// function and instantiates an appropriate lease manager 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. +/// +/// @todo: Will need to develop some form of registration mechanism for +/// user-supplied backends (so that there is no need to modify the code). +class LeaseMgrFactory { +public: + /// @brief Create an instance of a lease manager. + /// + /// Each database backend has its own lease manager type. This static + /// method sets the "current" lease manager to be a manager of the + /// appropriate type. The actual lease manager is returned by the + /// "instance" method. + /// + /// @note When called, the current lease manager is <b>always</b> destroyed + /// and a new one created - even if the parameters are the same. + /// + /// 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 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 create(const std::string& dbaccess); + + /// @brief Destroy lease manager + /// + /// Destroys the current lease manager object. This should have the effect + /// of closing the database connection. The method is a no-op if no + /// lease manager is available. + static void destroy(); + + /// @brief Recreate an instance of a lease manager with optionally + /// preserving registered callbacks. + /// + /// @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 preserve_callbacks a boolean flag indicating if all registered + /// @c TrackingLeaseMgr callbacks should be copied to the new + /// instance. + static void recreate(const std::string& dbaccess, + bool preserve_callbacks = true); + + /// @brief Return current lease manager + /// + /// Returns an instance of the "current" lease manager. An exception + /// will be thrown if none is available. + /// + /// @throw isc::dhcp::NoLeaseManager No lease manager is available: use + /// create() to create one before calling this method. + static TrackingLeaseMgr& instance(); + + /// @brief Indicates if the lease manager has been instantiated. + /// + /// @return True if the lease manager instance exists, false otherwise. + static bool haveInstance(); + +private: + /// @brief Hold pointer to lease manager + /// + /// Holds a pointer to the singleton lease manager. The singleton + /// is encapsulated in this method to avoid a "static initialization + /// fiasco" if defined in an external static variable. + static boost::scoped_ptr<TrackingLeaseMgr>& getLeaseMgrPtr(); + +}; + +} // end of isc::dhcp namespace +} // end of isc namespace + +#endif // LEASE_MGR_FACTORY_H |