/*
 * Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer. 
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution. 
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef ThreadingPrimitives_h
#define ThreadingPrimitives_h

#include <wtf/Platform.h>

#include <wtf/Assertions.h>
#include <wtf/FastAllocBase.h>
#include <wtf/Locker.h>
#include <wtf/Noncopyable.h>

#if OS(WINDOWS)
#include <windows.h>
#endif

#if USE(PTHREADS)
#include <pthread.h>
#endif

namespace WTF {

#if USE(PTHREADS)
typedef pthread_mutex_t PlatformMutex;
typedef pthread_cond_t PlatformCondition;
#elif OS(WINDOWS)
struct PlatformMutex {
    CRITICAL_SECTION m_internalMutex;
    size_t m_recursionCount;
};
struct PlatformCondition {
    size_t m_waitersGone;
    size_t m_waitersBlocked;
    size_t m_waitersToUnblock; 
    HANDLE m_blockLock;
    HANDLE m_blockQueue;
    HANDLE m_unblockLock;

    bool timedWait(PlatformMutex&, DWORD durationMilliseconds);
    void signal(bool unblockAll);
};
#else
typedef void* PlatformMutex;
typedef void* PlatformCondition;
#endif
    
class Mutex {
    WTF_MAKE_NONCOPYABLE(Mutex); WTF_MAKE_FAST_ALLOCATED;
public:
    WTF_EXPORT_PRIVATE Mutex();
    WTF_EXPORT_PRIVATE ~Mutex();

    WTF_EXPORT_PRIVATE void lock();
    WTF_EXPORT_PRIVATE bool tryLock();
    WTF_EXPORT_PRIVATE void unlock();

public:
    PlatformMutex& impl() { return m_mutex; }
private:
    PlatformMutex m_mutex;
};

typedef Locker<Mutex> MutexLocker;

class MutexTryLocker {
    WTF_MAKE_NONCOPYABLE(MutexTryLocker);
public:
    MutexTryLocker(Mutex& mutex) : m_mutex(mutex), m_locked(mutex.tryLock()) { }
    ~MutexTryLocker()
    {
        if (m_locked)
            m_mutex.unlock();
    }

    bool locked() const { return m_locked; }

private:
    Mutex& m_mutex;
    bool m_locked;
};

class ThreadCondition {
    WTF_MAKE_NONCOPYABLE(ThreadCondition);
public:
    WTF_EXPORT_PRIVATE ThreadCondition();
    WTF_EXPORT_PRIVATE ~ThreadCondition();
    
    WTF_EXPORT_PRIVATE void wait(Mutex& mutex);
    // Returns true if the condition was signaled before absoluteTime, false if the absoluteTime was reached or is in the past.
    // The absoluteTime is in seconds, starting on January 1, 1970. The time is assumed to use the same time zone as WTF::currentTime().
    WTF_EXPORT_PRIVATE bool timedWait(Mutex&, double absoluteTime);
    WTF_EXPORT_PRIVATE void signal();
    WTF_EXPORT_PRIVATE void broadcast();
    
private:
    PlatformCondition m_condition;
};

#if OS(WINDOWS)
// The absoluteTime is in seconds, starting on January 1, 1970. The time is assumed to use the same time zone as WTF::currentTime().
// Returns an interval in milliseconds suitable for passing to one of the Win32 wait functions (e.g., ::WaitForSingleObject).
WTF_EXPORT_PRIVATE DWORD absoluteTimeToWaitTimeoutInterval(double absoluteTime);
#endif

} // namespace WTF

using WTF::Mutex;
using WTF::MutexLocker;
using WTF::MutexTryLocker;
using WTF::ThreadCondition;

#if OS(WINDOWS)
using WTF::absoluteTimeToWaitTimeoutInterval;
#endif

#endif // ThreadingPrimitives_h
