/*
 * =====================================================================================
 *
 *       Filename:  shm_queue.cpp
 *
 *    Description:  
 *
 *        Version:  1.0
 *        Created:  2021年03月25日 10时34分42秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Li Chao (), 
 *   Organization:  
 *
 * =====================================================================================
 */

#include "shm_queue.h"
#include "bh_util.h"
#include <boost/uuid/uuid_generators.hpp>
#include <boost/uuid/uuid_io.hpp>

// TODO !!! add garbage collection, and handshake with gc-center.
// smart pointer will NOT work if user crash.
// problem of process release mq: client query success; server exits; client send.
//  client query success; server exits; client send.

namespace bhome_shm
{
using namespace bhome_msg;
using namespace boost::interprocess;
using namespace boost::uuids;

namespace
{
std::string MsgQIdToName(const MQId &id) { return "shmq" + to_string(id); }
// MQId EmptyId() { return nil_uuid(); }
MQId NewId() { return random_generator()(); }
const int AdjustMQLength(const int len)
{
	const int kMaxLength = 10000;
	const int kDefaultLen = 12;
	if (len <= 0) {
		return kDefaultLen;
	} else if (len < kMaxLength) {
		return len;
	} else {
		return kMaxLength;
	}
}

} // namespace

// ShmMsgQueue memory usage: (320 + 16*length) bytes, length >= 2
ShmMsgQueue::ShmMsgQueue(const MQId &id, ShmType &segment, const int len) :
    Super(segment, MsgQIdToName(id), AdjustMQLength(len), segment.get_segment_manager()),
    id_(id)
{
}

ShmMsgQueue::ShmMsgQueue(ShmType &segment, const int len) :
    ShmMsgQueue(NewId(), segment, len) {}

ShmMsgQueue::~ShmMsgQueue() {}

bool ShmMsgQueue::Remove(SharedMemory &shm, const MQId &id)
{
	return Super::Remove(shm, MsgQIdToName(id));
}

bool ShmMsgQueue::Send(SharedMemory &shm, const MQId &remote_id, const MsgI &msg, const int timeout_ms, OnSend const &onsend)
{
	Queue *remote = Find(shm, MsgQIdToName(remote_id));
	return remote && remote->Write(msg, timeout_ms, [&onsend](const MsgI &msg) { onsend(); msg.AddRef(); });
}
bool ShmMsgQueue::Send(SharedMemory &shm, const MQId &remote_id, const MsgI &msg, const int timeout_ms)
{
	Queue *remote = Find(shm, MsgQIdToName(remote_id));
	return remote && remote->Write(msg, timeout_ms, [](const MsgI &msg) { msg.AddRef(); });
}

// Test shows that in the 2 cases:
// 1) build msg first, then find remote queue;
// 2) find remote queue first, then build msg;
// 1 is about 50% faster than 2, maybe cache related.

// bool ShmMsgQueue::Recv(MsgI &imsg, BHMsgHead &head, const int timeout_ms)
// {
// 	if (Read(imsg, timeout_ms)) {
// 		// DEFER1(imsg.Release(shm()););
// 		return imsg.ParseHead(head);
// 	} else {
// 		return false;
// 	}
// }

} // namespace bhome_shm