// $Id$
//
// Copyright (C) 2006
// Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
// Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
// Stefan Bund <stefan.bund@fokus.fraunhofer.de>
//
// 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.,
// 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#ifndef HH_PacketRegistryImpl_
#define HH_PacketRegistryImpl_ 1
// Custom includes
#include <map>
#include <boost/utility.hpp> // for boost::noncopyable
#include <boost/shared_ptr.hpp>
#include "Packet.hh"
//#include "PacketRegistry.mpp"
///////////////////////////////hh.p////////////////////////////////////////
namespace senf {
namespace impl { template <class key> class PacketRegistryImpl; }
/** \brief Packet registration facility
The PacketRegistry provides a generic facility to associate an
arbitrary key with Packets. Example keys are Ethertype or IP
protocols.
Every PacketRegistry is identified by a type tag:
\code
struct SomeTag {
typedef some_key_type key_t;
};
\endcode
The key type can be an arbitrary value type. The PacketRegistry
for this Tag can then be accessed using
<code>PacketRegistry<SomeTag>::</code>.
The PacketRegistry class has only static members and provides
access to the packet registry. It allows to register Packet
classes and to create new Packets given a key. Methods are
also provided to find the key of a Packet type.
\code
PacketRegistry<SomeTag>::registerPacket<SomePacket>(key_of_somePacket);
p = PacketRegistry<SomeTag>::create(some_key,begin,end);
SomeTag::key_t key = PacketRegistry<SomeTag>::key<SomePacket>();
\endcode
Normally, packet classes are registered statically and not
procedurally. To this end, the RegistrationProxy is provided:
\code
PacketRegistry<SomeTag>::RegistrationProxy<SomePacket>
registerSomePacket (key_of_somePacket);
\endcode
This global variable declaration will register \c SomePacket
with the \c SomeTag registry under the key \c
key_of_somePacket. The variable \c registerSomePacket is a
dummy. It's only function is to force the call of it's
constructor during global construction time.
The PacketRegistry's purpose is mostly to assist in
implementing the v_nextInterpreter() member of packet
facades. This is further supported by the PacketRegistryMixin
class.
\todo Add parameterless create() method
*/
template <class Tag>
class PacketRegistry
{
public:
/** \brief Statically register a packet type in a PacketRegistry
*/
template <class OtherPacket>
struct RegistrationProxy
{
RegistrationProxy(typename Tag::key_t key);
};
/** \brief Register new packet type
Register \c OtherPacket in the packet registry \c Tag
under the given \c key.
\par Preconditions:
The given \c key must be unique and not be assigned to
any other packet class in this registry.
The Packet must not already be registered in the registry.
\param OtherPacket packet to register
\param key key of the packet
*/
template <class OtherPacket>
static void registerPacket(typename Tag::key_t key);
/** \brief Find key of a packet
Return the key of \c OtherPacket as registered in the \c
Tag registry
\param OtherPacket packet of which the key is requested
\returns key of the packet
\throws PacketTypeNotRegistered if the packet type is not
found in the registry.
*/
template <class OtherPacket>
static typename Tag::key_t key();
/** \brief Create new Packet
\param key Key of packet type to create instance of
\param b begin iterator argument to Packet::create()
\param e end iterator argument to Packet::create()
\returns new Instance of the packet type registered under
key or DataPacket, if the key is not registered.
*/
template <class InputIterator>
static Packet::ptr create(typename Tag::key_t key, InputIterator b, InputIterator e);
private:
typedef impl::PacketRegistryImpl<typename Tag::key_t> Registry;
static Registry & registry();
template <class T, class D> friend class PacketRegistryMixin;
};
/** \brief Helper class for v_nextInterpreter implementations
This class is a helper class which is to be inherited from in
a packet facade which wants to register a new interpreter with
the packet framework depending on a packet registry.
This mixin class provides a new registerInterpreter
implementation which can be used besides the methods provided
by senf::Packet to add a new interpreter to the
interpreter chain.
\code
class SomePacket
: public Packet,
private PacketRegistryMixin<SomeTag,SomePacket>
{
using Packet::retgisterInterpreter;
using PacketRegistryMixin<SomeTag,SomePacket>::registerInterpreter;
virtual void v_nextInterpreter()
{
registerInterpreter(some_key_value, subpacket_begin, subpacket_end);
}
};
\endcode
This example is not complete, it only contains the parts
concerned with PacketRegistryMixin.
*/
template <class Tag, class Derived>
class PacketRegistryMixin
{
protected:
/** \brief add interpreter to interpreter chain
This method is used by v_nextInterpreter() to add a new
interpreter to the interpreter chain (see the Packet
reference for more). Instead of specifying the type of
packet to use as a template argument it is specified using
the \c key value from the \c Tag registry
*/
void registerInterpreter(typename Tag::key_t key,
Packet::iterator b, Packet::iterator e) const;
};
struct PacketTypeNotRegistered : public std::exception
{ virtual char const * what() const throw() { return "packet type not registered"; } };
}
///////////////////////////////hh.e////////////////////////////////////////
//#include "PacketRegistry.cci"
#include "PacketRegistry.ct"
#include "PacketRegistry.cti"
#endif
// Local Variables:
// mode: c++
// fill-column: 100
// c-file-style: "senf"
// indent-tabs-mode: nil
// ispell-local-dictionary: "american"
// compile-command: "scons -u test"
// comment-column: 40
// End: