/*

 * Copyright (C) 2007, 2008 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.

 *

 *

 * Note: The implementations of InterlockedIncrement and InterlockedDecrement are based

 * on atomic_increment and atomic_exchange_and_add from the Boost C++ Library. The license

 * is virtually identical to the Apple license above but is included here for completeness.

 *

 * Boost Software License - Version 1.0 - August 17th, 2003

 * 

 * Permission is hereby granted, free of charge, to any person or organization

 * obtaining a copy of the software and accompanying documentation covered by

 * this license (the "Software") to use, reproduce, display, distribute,

 * execute, and transmit the Software, and to prepare derivative works of the

 * Software, and to permit third-parties to whom the Software is furnished to

 * do so, all subject to the following:

 * 

 * The copyright notices in the Software and this entire statement, including

 * the above license grant, this restriction and the following disclaimer,

 * must be included in all copies of the Software, in whole or in part, and

 * all derivative works of the Software, unless such copies or derivative

 * works are solely in the form of machine-executable object code generated by

 * a source language processor.

 * 

 * 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, TITLE AND NON-INFRINGEMENT. IN NO EVENT

 * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE

 * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,

 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */

#ifndef Threading_h

#define Threading_h

#include "Platform.h"

#if PLATFORM(WINCE)

#include <windows.h>

#endif

#include <wtf/Assertions.h>

#include <wtf/Locker.h>

#include <wtf/Noncopyable.h>

#if PLATFORM(WIN_OS) && !PLATFORM(WINCE)

#include <windows.h>

#elif PLATFORM(DARWIN)

#include <libkern/OSAtomic.h>

#if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 2))

#include <ext/atomicity.h>

#else

#include <bits/atomicity.h>

#endif

#endif

#if USE(PTHREADS)

#include <pthread.h>

#elif PLATFORM(GTK)

#include <wtf/GOwnPtr.h>

typedef struct _GMutex GMutex;

typedef struct _GCond GCond;

#endif

#if PLATFORM(QT)

#include <qglobal.h>

QT_BEGIN_NAMESPACE

class QMutex;

class QWaitCondition;

QT_END_NAMESPACE

#endif

#include <stdint.h>

// For portability, we do not use thread-safe statics natively supported by some compilers (e.g. gcc).

#define AtomicallyInitializedStatic(T, name) \

    WTF::lockAtomicallyInitializedStaticMutex(); \

    static T name; \

    WTF::unlockAtomicallyInitializedStaticMutex();

namespace WTF {

typedef uint32_t ThreadIdentifier;

typedef void* (*ThreadFunction)(void* argument);

// Returns 0 if thread creation failed.

// The thread name must be a literal since on some platforms it's passed in to the thread.

ThreadIdentifier createThread(ThreadFunction, void*, const char* threadName);

// Internal platform-specific createThread implementation.

ThreadIdentifier createThreadInternal(ThreadFunction, void*, const char* threadName);

// Called in the thread during initialization.

// Helpful for platforms where the thread name must be set from within the thread.

void setThreadNameInternal(const char* threadName);

ThreadIdentifier currentThread();

bool isMainThread();

int waitForThreadCompletion(ThreadIdentifier, void**);

void detachThread(ThreadIdentifier);

#if USE(PTHREADS)

typedef pthread_mutex_t PlatformMutex;

typedef pthread_rwlock_t PlatformReadWriteLock;

typedef pthread_cond_t PlatformCondition;

#elif PLATFORM(GTK)

typedef GOwnPtr<GMutex> PlatformMutex;

typedef void* PlatformReadWriteLock; // FIXME: Implement.

typedef GOwnPtr<GCond> PlatformCondition;

#elif PLATFORM(QT)

typedef QT_PREPEND_NAMESPACE(QMutex)* PlatformMutex;

typedef void* PlatformReadWriteLock; // FIXME: Implement.

typedef QT_PREPEND_NAMESPACE(QWaitCondition)* PlatformCondition;

#elif PLATFORM(WIN_OS)

struct PlatformMutex {

    CRITICAL_SECTION m_internalMutex;

    size_t m_recursionCount;

};

typedef void* PlatformReadWriteLock; // FIXME: Implement.

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* PlatformReadWriteLock;

typedef void* PlatformCondition;

#endif

class Mutex : public Noncopyable {

public:

    Mutex();

    ~Mutex();

    void lock();

    bool tryLock();

    void unlock();

public:

    PlatformMutex& impl() { return m_mutex; }

private:

    PlatformMutex m_mutex;

};

typedef Locker<Mutex> MutexLocker;

class ReadWriteLock : public Noncopyable {

public:

    ReadWriteLock();

    ~ReadWriteLock();

    void readLock();

    bool tryReadLock();

    void writeLock();

    bool tryWriteLock();

    void unlock();

private:

    PlatformReadWriteLock m_readWriteLock;

};

class ThreadCondition : public Noncopyable {

public:

    ThreadCondition();

    ~ThreadCondition();

    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().

    bool timedWait(Mutex&, double absoluteTime);

    void signal();

    void broadcast();

private:

    PlatformCondition m_condition;

};

#if PLATFORM(WIN_OS)

#define WTF_USE_LOCKFREE_THREADSAFESHARED 1

#if COMPILER(MINGW) || COMPILER(MSVC7) || PLATFORM(WINCE)

inline int atomicIncrement(int* addend) { return InterlockedIncrement(reinterpret_cast<long*>(addend)); }

inline int atomicDecrement(int* addend) { return InterlockedDecrement(reinterpret_cast<long*>(addend)); }

#else

inline int atomicIncrement(int volatile* addend) { return InterlockedIncrement(reinterpret_cast<long volatile*>(addend)); }

inline int atomicDecrement(int volatile* addend) { return InterlockedDecrement(reinterpret_cast<long volatile*>(addend)); }

#endif

#elif PLATFORM(DARWIN)

#define WTF_USE_LOCKFREE_THREADSAFESHARED 1

inline int atomicIncrement(int volatile* addend) { return OSAtomicIncrement32Barrier(const_cast<int*>(addend)); }

inline int atomicDecrement(int volatile* addend) { return OSAtomicDecrement32Barrier(const_cast<int*>(addend)); }

#define WTF_USE_LOCKFREE_THREADSAFESHARED 1

inline int atomicIncrement(int volatile* addend) { return __gnu_cxx::__exchange_and_add(addend, 1) + 1; }

inline int atomicDecrement(int volatile* addend) { return __gnu_cxx::__exchange_and_add(addend, -1) - 1; }

#endif

class ThreadSafeSharedBase : public Noncopyable {

public:

    ThreadSafeSharedBase(int initialRefCount = 1)

        : m_refCount(initialRefCount)

    {

    }

    void ref()

    {

#if USE(LOCKFREE_THREADSAFESHARED)

        atomicIncrement(&m_refCount);

#else

        MutexLocker locker(m_mutex);

        ++m_refCount;

#endif

    }

    bool hasOneRef()

    {

        return refCount() == 1;

    }

    int refCount() const

    {

#if !USE(LOCKFREE_THREADSAFESHARED)

        MutexLocker locker(m_mutex);

#endif

        return static_cast<int const volatile &>(m_refCount);

    }

protected:

    // Returns whether the pointer should be freed or not.

    bool derefBase()

    {

#if USE(LOCKFREE_THREADSAFESHARED)

        if (atomicDecrement(&m_refCount) <= 0)

            return true;

#else

        int refCount;

        {

            MutexLocker locker(m_mutex);

            --m_refCount;

            refCount = m_refCount;

        }

        if (refCount <= 0)

            return true;

#endif

        return false;

    }

private:

    template<class T>

    friend class CrossThreadRefCounted;

    int m_refCount;

#if !USE(LOCKFREE_THREADSAFESHARED)

    mutable Mutex m_mutex;

#endif

};

template<class T> class ThreadSafeShared : public ThreadSafeSharedBase {

public:

    ThreadSafeShared(int initialRefCount = 1)

        : ThreadSafeSharedBase(initialRefCount)

    {

    }

    void deref()

    {

        if (derefBase())

            delete static_cast<T*>(this);

    }

};

// This function must be called from the main thread. It is safe to call it repeatedly.

// Darwin is an exception to this rule: it is OK to call it from any thread, the only requirement is that the calls are not reentrant.

void initializeThreading();

void lockAtomicallyInitializedStaticMutex();

void unlockAtomicallyInitializedStaticMutex();

} // namespace WTF

using WTF::Mutex;

using WTF::MutexLocker;

using WTF::ThreadCondition;

using WTF::ThreadIdentifier;

using WTF::ThreadSafeShared;

#if USE(LOCKFREE_THREADSAFESHARED)

using WTF::atomicDecrement;

using WTF::atomicIncrement;

#endif

using WTF::createThread;

using WTF::currentThread;

using WTF::isMainThread;

using WTF::detachThread;

using WTF::waitForThreadCompletion;

#endif // Threading_h