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

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;
    }
}

}

// 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()
{
    Remove();
}

bool ShmMsgQueue::Send(const MQId &remote_id, const Msg &msg, const int timeout_ms)
{
    Queue *remote = find(MsgQIdToName(remote_id));
    return remote && remote->Write(msg, timeout_ms, [](const Msg&msg){msg.AddRef();});
}

bool ShmMsgQueue::Send(const MQId &remote_id, const void *data, const size_t size, const int timeout_ms)
{
    // 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.

    Msg msg;
    if(msg.Build(shm(), Id(), data, size, false)) {
        if(Send(remote_id, msg, timeout_ms)) {
            return true;
        } else {
            msg.Release(shm());
        }
    }
    return false;
}

bool ShmMsgQueue::Recv(MQId &source_id, void *&data, size_t &size, const int timeout_ms)
{
    Msg msg;
    if (Read(msg, timeout_ms)) {
        DEFER1(msg.Release(shm()););

        auto ptr = msg.get<char>();
        if (ptr) {
            MsgMetaV1 meta;
            meta.Parse(ptr);
            source_id = meta.src_id_;
            size = meta.data_size_;
            data = malloc(size);
            if (data) {
                memcpy(data, ptr + meta.self_size_, size);
                return true;
            }
        }
    }
    source_id = EmptyId();
    data = 0;
    size = 0;
    return false;
}

} // namespace bhome_shm