Mutex.h

/*
 * Copyright (C) 2005-2008 by Marc Boris Duerner
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * As a special exception, you may use this file as part of a free
 * software library without restriction. Specifically, if other files
 * instantiate templates or use macros or inline functions from this
 * file, or you compile this file and link it with other files to
 * produce an executable, this file does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License. This exception does not however invalidate any other
 * reasons why the executable file might be covered by the GNU Library
 * General Public License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef Pt_System_Mutex_h
#define Pt_System_Mutex_h

#include <Pt/Atomicity.h>
#include <Pt/NonCopyable.h>
#include <Pt/System/Api.h>
#include <Pt/System/Thread.h>

namespace Pt {

namespace System {

class PT_SYSTEM_API Mutex : private NonCopyable
{
    private:
        class MutexImpl* _impl;

    public:
        Mutex();

        ~Mutex();

        void lock();

        bool tryLock();

        void unlock();

        bool unlockNoThrow();

        MutexImpl& impl()
        { return *_impl;  }
};

class MutexLock : private NonCopyable
{
    public:
        MutexLock(Mutex& m, bool doLock = true, bool isLocked = false)
        : _mutex(m)
        , _isLocked(isLocked)
        {
            if(doLock)
                this->lock();
        }

        ~MutexLock()
        {
            if(_isLocked)
                _mutex.unlockNoThrow();
        }
        
        void lock()
        {
            if(!_isLocked)
            {
                _mutex.lock();
                _isLocked = true;
            }
        }

        void unlock()
        {
            if(_isLocked)
            {
                _mutex.unlock();
                _isLocked = false;
            }
        }

        Mutex& mutex()
        { return _mutex; }

        const Mutex& mutex() const
        { return _mutex; }

        private:
            Mutex& _mutex;
            bool _isLocked;
};

class PT_SYSTEM_API RecursiveMutex : private NonCopyable
{
    private:
        class MutexImpl* _impl;

    public:
        RecursiveMutex();

        ~RecursiveMutex();

        void lock();

        bool tryLock();

        void unlock();

        bool unlockNoThrow();
};

class RecursiveLock : private NonCopyable
{
    public:
        RecursiveLock(RecursiveMutex& m, bool doLock = true, bool isLocked = false)
        : _mutex(m)
        , _isLocked(isLocked)
        {
            if(doLock)
                this->lock();
        }

        ~RecursiveLock()
        {
            if(_isLocked)
                _mutex.unlockNoThrow();
        }

        void lock()
        {
            if(!_isLocked)
            {
                _mutex.lock();
                _isLocked = true;
            }
        }

        void unlock()
        {
            if(_isLocked)
            {
                _mutex.unlock();
                _isLocked = false;
            }
        }

        RecursiveMutex& mutex()
        { return _mutex; }

        const RecursiveMutex& mutex() const
        { return _mutex; }

    private:
        RecursiveMutex& _mutex;
        bool _isLocked;
};

class PT_SYSTEM_API ReadWriteMutex : private NonCopyable
{
    public:
        ReadWriteMutex();

        ~ReadWriteMutex();

        void readLock();
        
        bool tryReadLock();

        void writeLock();

        bool tryWriteLock();

        void unlock();

        bool unlockNoThrow();

    private:
        class ReadWriteMutexImpl* _impl;
};

class ReadLock : private NonCopyable
{
    public:
        ReadLock(ReadWriteMutex& m, bool doLock = true, bool isLocked = false)
        : _mutex(m)
        , _locked(isLocked)
        {
            if(doLock)
                this->lock();
        }

        ~ReadLock()
        {
            if(_locked)
                _mutex.unlockNoThrow();
        }

        void lock()
        {
            if( ! _locked )
            {
                _mutex.readLock();
                _locked = true;
            }
        }
        
        void unlock()
        {
            if( _locked)
            {
                _mutex.unlock();
                _locked = false;
            }
        }

        ReadWriteMutex& mutex()
        { return _mutex; }

    private:
        ReadWriteMutex& _mutex;
        bool _locked;
};

class WriteLock : private NonCopyable
{
    public:
        WriteLock(ReadWriteMutex& m, bool doLock = true, bool isLocked = false)
        : _mutex(m)
        , _locked(isLocked)
        {
            if(doLock)
                this->lock();
        }

        ~WriteLock()
        {
            if(_locked)
                _mutex.unlockNoThrow();
        }

        void lock()
        {
            if( ! _locked )
            {
                _mutex.writeLock();
                _locked = true;
            }
        }

        void unlock()
        {
            if( _locked)
            {
                _mutex.unlock();
                _locked = false;
            }
        }

        ReadWriteMutex& mutex()
        { return _mutex; }

    private:
        ReadWriteMutex& _mutex;
        bool _locked;
};


class SpinMutex : private NonCopyable
{
    public:
        SpinMutex()
        : _count(0)
        {}

        ~SpinMutex()
        {}

        inline void lock()
        {
            // busy loop until unlock
            while( atomicCompareExchange(_count, 1, 0) )
            {
                Thread::yield();
            }
        }

        bool tryLock()
        {
           return ! atomicCompareExchange(_count, 1, 0);
        }

        void unlock()
        {
            // set unlocked
            atomicExchange(_count, 0);
        }

        bool testIsLocked() const
        { return atomicGet(const_cast<volatile Pt::atomic_t&>(_count)) != 0; }

    private:
        volatile Pt::atomic_t _count;
};

class SpinLock : private NonCopyable
{
    public:
        SpinLock(SpinMutex& m, bool doLock = true, bool isLocked = false)
        : _mutex(m)
        , _locked(isLocked)
        {
            if(doLock)
                this->lock();
        }

        ~SpinLock()
        {
            if(_locked)
                this->unlock();
        }

        void lock()
        {
            if( ! _locked )
            {
                _mutex.lock();
                _locked = true;
            }
        }

        void unlock()
        {
            if( _locked)
            {
                _mutex.unlock();
                _locked = false;
            }
        }

    private:
        SpinMutex& _mutex;
        bool _locked;
};

} // namespace System

} // namespace Pt

#endif // Pt_System_Mutex_h