//  parallel_channel.cpp
/*
 The MIT License (MIT)
 Copyright (c) 2018 HouSisong
 
 Permission is hereby granted, free of charge, to any person
 obtaining a copy of this software and associated documentation
 files (the "Software"), to deal in the Software without
 restriction, including without limitation the rights to use,
 copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the
 Software is furnished to do so, subject to the following
 conditions:
 
 The above copyright notice and this permission notice shall be
 included in all copies of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 OTHER DEALINGS IN THE SOFTWARE.
 */
#include "parallel_channel.h"

#if (_IS_USED_MULTITHREAD)
#include <assert.h>
#include <deque>

class _CChannel_import{
public:
    explicit _CChannel_import(ptrdiff_t maxDataCount)
    :_locker(0),_sendCond(0),_acceptCond(0),
    _maxDataCount(maxDataCount),_waitingCount(0),_isClosed(false){
        _locker=locker_new();
        _sendCond=condvar_new();
        _acceptCond=condvar_new();
    }
    ~_CChannel_import(){
        close();
        while (true) { //wait all thread exit
            {
                CAutoLocker locker(_locker);
                if (_waitingCount==0) break;
            }
            this_thread_yield(); //todo:优化?
        }
        locker_delete(_locker);
        assert(_dataList.empty()); // why? if saved resource then leaks
        condvar_delete(_acceptCond);
        condvar_delete(_sendCond);
    }
    void close(){
        if (_isClosed) return;
        {
            CAutoLocker locker(_locker);
            if (_isClosed) return;
            _isClosed=true;
            condvar_broadcast(_sendCond);
            condvar_broadcast(_acceptCond);
        }
    }
    bool is_can_fast_send(bool isWait){
        if (_maxDataCount<0) return true;
        if (_maxDataCount==0) return false;

        CAutoLocker locker(_locker);
        while (true) {
            if (_isClosed) return false;
            if (_dataList.size()<(size_t)_maxDataCount) {
                return true;
            }else if(!isWait){
                return false;
            }//else wait
            ++_waitingCount;
            condvar_wait(_sendCond,&locker);
            --_waitingCount;
        }
    }

    bool send(TChanData data,bool isWait){
        assert(data!=0);
        {
            CAutoLocker locker(_locker);
            while (true) {
                if (_isClosed) return false;
                if ((_maxDataCount<=0)||(_dataList.size()<(size_t)_maxDataCount)) {
                    try{
                        _dataList.push_back(data);
                    }catch(...){
                        return false;
                    }
                    condvar_signal(_acceptCond);
                    if (_maxDataCount==0) //must wait accepted?
                        break;// to wait accepted
                    else
                        return true; //ok
                }else if(!isWait){
                    return false;
                }//else wait
                ++_waitingCount;
                condvar_wait(_sendCond,&locker);
                --_waitingCount;
            }
        }

        //wait accepted
        while (true) { //wait _dataList empty
            {
                CAutoLocker locker(_locker);
                if (_isClosed) break;
                if (_dataList.empty()) break;
            }
            this_thread_yield(); //todo:优化;
        }
        return true;
    }
    TChanData accept(bool isWait){
        CAutoLocker locker(_locker);
        while (true) {
            if (!_dataList.empty()) {
                TChanData result=_dataList.front();
                _dataList.pop_front();
                if (!_isClosed)
                    condvar_signal(_sendCond);
                return result; //ok
            }else if(_isClosed){
                return 0;
            }else if(!isWait){
                return 0;
            }//else wait
            ++_waitingCount;
            condvar_wait(_acceptCond,&locker);
            --_waitingCount;
        }
    }
private:
    HLocker     _locker;
    HCondvar    _sendCond;
    HCondvar    _acceptCond;
    std::deque<TChanData>   _dataList;
    const ptrdiff_t         _maxDataCount;
    volatile size_t         _waitingCount;
    volatile bool           _isClosed;
};


CChannel::CChannel(ptrdiff_t maxDataCount):_import(0){
    _import=new _CChannel_import(maxDataCount);
}
CChannel::~CChannel(){
    delete (_CChannel_import*)_import;
}
void CChannel::close(){
    _import->close();
}
bool CChannel::is_can_fast_send(bool isWait){
    return _import->is_can_fast_send(isWait);
}
bool CChannel::send(TChanData data,bool isWait){
    return _import->send(data,isWait);
}
TChanData CChannel::accept(bool isWait){
    return _import->accept(isWait);
}

#endif //_IS_USED_MULTITHREAD