/*
 * =====================================================================================
 *
 *       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"

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

namespace
{
std::string MsgQIdToName(const ShmMsgQueue::MQId id)
{
	char buf[40] = "mqOx";
	int n = sprintf(buf + 4, "%lx", id);
	return std::string(buf, n + 4);
}

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::MQId ShmMsgQueue::NewId()
{
	static auto &id = GetData();
	return ++id;
}
// 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)
{
	Queue *q = Find(shm, id);
	if (q) {
		MsgI msg;
		while (q->TryRead(msg)) {
			msg.Release();
		}
	}
	return Super::Remove(shm, MsgQIdToName(id));
}

ShmMsgQueue::Queue *ShmMsgQueue::Find(SharedMemory &shm, const MQId remote_id)
{
	return Super::Find(shm, MsgQIdToName(remote_id));
}

bool ShmMsgQueue::TrySend(SharedMemory &shm, const MQId remote_id, const MsgI &msg, OnSend const &onsend)
{
	Queue *remote = Find(shm, remote_id);
	if (remote) {
		if (onsend) {
			return remote->TryWrite(msg, [&onsend](const MsgI &msg) { onsend(); msg.AddRef(); });
		} else {
			return remote->TryWrite(msg, [](const MsgI &msg) { msg.AddRef(); });
		}
	} else {
		// SetLestError(eNotFound);
		return false;
	}
}

// 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.

} // namespace bhome_shm