Mutex.h

#pragma once


#include <libutl/host_thread.h>
#include <libutl/NamedObjectMI.h>


UTL_NS_BEGIN;

// Mutex ///////////////////////////////////////////////////////////////////////////////////////////


class Mutex : public Object, public NamedObjectMI
{
    friend class ConditionVar;
    UTL_CLASS_DECL(Mutex, Object);
    UTL_CLASS_NO_COPY;

public:
    bool haveLock() const;

    bool trylock();

    void lock();

    void unlock();

private:
    void init();
    void deInit();

private:
#if UTL_HOST_OS == UTL_OS_MINGW
    HANDLE _sem;
    volatile long _count;
#else
    pthread_mutex_t _mutex;
#endif
    thread_handle_t _owner;
    size_t _depth; // recursive locking depth
};

// MutexGuard //////////////////////////////////////////////////////////////////////////////////////


class MutexGuard
{
public:
    MutexGuard()
        : _mutex(nullptr)
    {
    }

    MutexGuard(Mutex* mutex)
        : _mutex(mutex)
    {
        ASSERTD(_mutex != nullptr);
        _mutex->lock();
    }

    ~MutexGuard()
    {
        unlock();
    }

    void
    lock(Mutex* mutex)
    {
        unlock();
        ASSERTD(mutex != nullptr);
        _mutex = mutex;
        _mutex->lock();
    }

    bool
    trylock(Mutex* mutex)
    {
        unlock();
        ASSERTD(mutex != nullptr);
        if (mutex->trylock())
        {
            _mutex = mutex;
            return true;
        }
        else
        {
            return false;
        }
    }

    void
    unlock()
    {
        if (_mutex != nullptr)
        {
            _mutex->unlock();
            _mutex = nullptr;
        }
    }

private:
    Mutex* _mutex;
};


UTL_NS_END;