/*
 * Copyright 2007, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *      Hugo Santos, hugosantos@gmail.com
 */

#ifndef PROTOCOL_UTILITIES_H
#define PROTOCOL_UTILITIES_H

#include <lock.h>
#include <util/AutoLock.h>
#include <util/DoublyLinkedList.h>

#include <net_buffer.h>
#include <net_socket.h>
#include <net_stack.h>

class BenaphoreLocking {
public:
	typedef benaphore Type;
	typedef BenaphoreLocker AutoLocker;

	static status_t Init(benaphore *lock, const char *name)
		{ return benaphore_init(lock, name); }
	static void Destroy(benaphore *lock) { benaphore_destroy(lock); }
	static status_t Lock(benaphore *lock) { return benaphore_lock(lock); }
	static status_t Unlock(benaphore *lock) { return benaphore_unlock(lock); }
};


extern net_stack_module_info *gStackModule;
extern net_buffer_module_info *gBufferModule;

class NetModuleBundle {
public:
	static net_stack_module_info *Stack() { return gStackModule; }
	static net_buffer_module_info *Buffer() { return gBufferModule; }
};


template<typename LockingBase = BenaphoreLocking,
	typename ModuleBundle = NetModuleBundle>
class DatagramSocket {
public:
	DatagramSocket(const char *name, net_socket *socket);
	~DatagramSocket();

	status_t InitCheck() const;

	status_t Enqueue(net_buffer *buffer);
	status_t EnqueueClone(net_buffer *buffer);
	net_buffer *Dequeue(bool clone);
	status_t BlockingDequeue(bool clone, bigtime_t timeout,
		net_buffer **_buffer);
	status_t SocketDequeue(uint32 flags, net_buffer **_buffer);
	void Clear();

	size_t AvailableData() const;

	void WakeAll();

protected:
	status_t _Enqueue(net_buffer *buffer);
	status_t _EnqueueClone(net_buffer *buffer);
	net_buffer *_Dequeue(bool clone);
	void _Clear();

	status_t _Wait(bigtime_t timeout);
	void _NotifyOneReader(bool notifySocket);

	bool _IsEmpty() const { return fBuffers.IsEmpty(); }
	bigtime_t _SocketTimeout(uint32 flags) const;

	typedef typename LockingBase::Type LockType;
	typedef typename LockingBase::AutoLocker AutoLocker;
	typedef DoublyLinkedListCLink<net_buffer> NetBufferLink;
	typedef DoublyLinkedList<net_buffer, NetBufferLink> BufferList;

	status_t fStatus;
	net_socket *fSocket;
	sem_id fNotify;
	BufferList fBuffers;
	size_t fCurrentBytes;
	mutable LockType fLock;
};


#define DECL_DATAGRAM_SOCKET(args) \
	template<typename LockingBase, typename ModuleBundle> args \
	DatagramSocket<LockingBase, ModuleBundle>


DECL_DATAGRAM_SOCKET(inline)::DatagramSocket(const char *name,
	net_socket *socket)
	: fSocket(socket), fCurrentBytes(0)
{
	fStatus = LockingBase::Init(&fLock, name);
	if (fStatus >= B_OK)
		fNotify = create_sem(0, name);
}


DECL_DATAGRAM_SOCKET(inline)::~DatagramSocket()
{
	_Clear();

	if (fStatus >= B_OK) {
		delete_sem(fNotify);
		LockingBase::Destroy(&fLock);
	}
}


DECL_DATAGRAM_SOCKET(inline status_t)::InitCheck() const
{
	if (fStatus < 0)
		return fStatus;
	return fNotify;
}


DECL_DATAGRAM_SOCKET(inline status_t)::Enqueue(net_buffer *buffer)
{
	AutoLocker _(fLock);
	return _Enqueue(buffer);
}


DECL_DATAGRAM_SOCKET(inline status_t)::_Enqueue(net_buffer *buffer)
{
	if (fSocket->receive.buffer_size > 0
		&& (fCurrentBytes + buffer->size) > fSocket->receive.buffer_size)
		return ENOBUFS;

	fBuffers.Add(buffer);
	fCurrentBytes += buffer->size;

	_NotifyOneReader(true);

	return B_OK;
}


DECL_DATAGRAM_SOCKET(inline status_t)::EnqueueClone(net_buffer *_buffer)
{
	AutoLocker _(fLock);
	return _EnqueueClone(_buffer);
}


DECL_DATAGRAM_SOCKET(inline status_t)::_EnqueueClone(net_buffer *_buffer)
{
	net_buffer *buffer = ModuleBundle::Buffer()->clone(_buffer, false);
	if (buffer == NULL)
		return B_NO_MEMORY;

	status_t status = _Enqueue(buffer);
	if (status < B_OK)
		ModuleBundle::Buffer()->free(buffer);

	return status;
}


DECL_DATAGRAM_SOCKET(inline net_buffer *)::Dequeue(bool clone)
{
	AutoLocker _(fLock);
	return _Dequeue(clone);
}


DECL_DATAGRAM_SOCKET(inline net_buffer *)::_Dequeue(bool clone)
{
	if (fBuffers.IsEmpty())
		return NULL;

	if (clone)
		return ModuleBundle::Buffer()->clone(fBuffers.Head(), false);

	net_buffer *buffer = fBuffers.RemoveHead();
	fCurrentBytes -= buffer->size;

	return buffer;
}


DECL_DATAGRAM_SOCKET(inline status_t)::BlockingDequeue(bool clone,
	bigtime_t timeout, net_buffer **_buffer)
{
	AutoLocker _(fLock);

	bool waited = false;

	while (fBuffers.IsEmpty()) {
		status_t status = _Wait(timeout);
		if (status < B_OK)
			return status;
		waited = true;
	}

	*_buffer = _Dequeue(clone);
	if (clone && waited) {
		// we were signalled there was a new buffer in the
		// list; but since we are cloning, notify the next
		// waiting reader.
		_NotifyOneReader(false);
	}

	if (*_buffer == NULL)
		return B_NO_MEMORY;

	return B_OK;
}


DECL_DATAGRAM_SOCKET(inline status_t)::SocketDequeue(uint32 flags,
	net_buffer **_buffer)
{
	return BlockingDequeue(flags & MSG_PEEK, _SocketTimeout(flags), _buffer);
}


DECL_DATAGRAM_SOCKET(inline void)::Clear()
{
	AutoLocker _(fLock);
	_Clear();
}


DECL_DATAGRAM_SOCKET(inline void)::_Clear()
{
	BufferList::Iterator it = fBuffers.GetIterator();
	while (it.HasNext())
		ModuleBundle::Buffer()->free(it.Next());
	fCurrentBytes = 0;
}


DECL_DATAGRAM_SOCKET(inline size_t)::AvailableData() const
{
	AutoLocker _(fLock);
	return fCurrentBytes;
}


DECL_DATAGRAM_SOCKET(inline status_t)::_Wait(bigtime_t timeout)
{
	LockingBase::Unlock(&fLock);
	status_t status = acquire_sem_etc(fNotify, 1, B_CAN_INTERRUPT
		| B_ABSOLUTE_TIMEOUT, timeout);
	LockingBase::Lock(&fLock);

	return status;
}


DECL_DATAGRAM_SOCKET(inline void)::WakeAll()
{
	release_sem_etc(fNotify, 0, B_RELEASE_ALL);
}


DECL_DATAGRAM_SOCKET(inline void)::_NotifyOneReader(bool notifySocket)
{
	release_sem_etc(fNotify, 1, B_RELEASE_IF_WAITING_ONLY
		| B_DO_NOT_RESCHEDULE);

	if (notifySocket)
		ModuleBundle::Stack()->notify_socket(fSocket, B_SELECT_READ,
			fCurrentBytes);
}


DECL_DATAGRAM_SOCKET(inline bigtime_t)::_SocketTimeout(uint32 flags) const
{
	bigtime_t timeout = fSocket->receive.timeout;

	if (flags & MSG_DONTWAIT)
		timeout = 0;
	else if (timeout != 0 && timeout != B_INFINITE_TIMEOUT)
		timeout += system_time();

	return timeout;
}

#endif