LockedContainer.h

// This file is a part of the OpenSurgSim project.
// Copyright 2013, SimQuest Solutions Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SURGSIM_FRAMEWORK_LOCKEDCONTAINER_H
#define SURGSIM_FRAMEWORK_LOCKEDCONTAINER_H

#include <boost/thread/mutex.hpp>
#include <boost/thread/locks.hpp>


namespace SurgSim
{
namespace Framework
{

template <typename T>
class LockedContainer
{
public:
    LockedContainer() :
        m_buffer(),
        m_haveNewData(false)
    {
    }

    explicit LockedContainer(const T& initialValue) :
        m_buffer(initialValue),
        m_haveNewData(false)
    {
    }

    explicit LockedContainer(T&& initialValue) :
        m_buffer(std::move(initialValue)),
        m_haveNewData(false)
    {
    }


    ~LockedContainer()
    {
    }

    void set(const T& value)
    {
        boost::lock_guard<boost::mutex> lock(m_mutex);
        m_buffer = value;
        m_haveNewData = true;
    }

    void set(T&& value)
    {
        boost::lock_guard<boost::mutex> lock(m_mutex);
        m_buffer = std::move(value);
        m_haveNewData = true;
    }

    void get(T* value) const
    {
        boost::lock_guard<boost::mutex> lock(m_mutex);
        m_haveNewData = false;
        *value = m_buffer;
    }

    void take(T* value)
    {
        boost::lock_guard<boost::mutex> lock(m_mutex);
        m_haveNewData = false;
        *value = std::move(m_buffer);
    }

    bool tryGetChanged(T* value) const
    {
        boost::lock_guard<boost::mutex> lock(m_mutex);
        if (! m_haveNewData)
        {
            return false;
        }
        else
        {
            m_haveNewData = false;
            *value = m_buffer;
            return true;
        }
    }

    bool tryTakeChanged(T* value)
    {
        boost::lock_guard<boost::mutex> lock(m_mutex);
        if (! m_haveNewData)
        {
            return false;
        }
        else
        {
            m_haveNewData = false;
            *value = std::move(m_buffer);
            return true;
        }
    }

private:
    LockedContainer(const LockedContainer&);
    LockedContainer& operator=(const LockedContainer&);


    T m_buffer;

    mutable bool m_haveNewData;

    mutable boost::mutex m_mutex;
};

};  // namespace Framework
};  // namespace SurgSim

#endif  // SURGSIM_FRAMEWORK_LOCKEDCONTAINER_H