/*

 * Copyright (C) 2009 Google Inc. All rights reserved.

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 * modification, are permitted provided that the following conditions are

 * met:

 *

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 * notice, this list of conditions and the following disclaimer.

 *     * 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.

 *     * Neither the name of Google Inc. 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 THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT

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 */

#ifndef ThreadIdentifierDataPthreads_h

#define ThreadIdentifierDataPthreads_h

#include <wtf/Noncopyable.h>

#include <wtf/Threading.h>

namespace WTF {

// Holds ThreadIdentifier in the thread-specific storage and employs pthreads-specific 2-pass destruction to reliably remove

// ThreadIdentifier from threadMap. It assumes regular ThreadSpecific types don't use multiple-pass destruction.

class ThreadIdentifierData : public Noncopyable {

public:

    ~ThreadIdentifierData();

    // Creates and puts an instance of ThreadIdentifierData into thread-specific storage.

    static void initialize(ThreadIdentifier identifier);

    // Returns 0 if thread-specific storage was not initialized.

    static ThreadIdentifier identifier();

private:

    ThreadIdentifierData(ThreadIdentifier identifier)

        : m_identifier(identifier)

        , m_isDestroyedOnce(false)

    {

    }

    // This thread-specific destructor is called 2 times when thread terminates:

    // - first, when all the other thread-specific destructors are called, it simply remembers it was 'destroyed once'

    // and re-sets itself into the thread-specific slot to make Pthreads to call it again later.

    // - second, after all thread-specific destructors were invoked, it gets called again - this time, we remove the

    // ThreadIdentifier from the threadMap, completing the cleanup.

    static void destruct(void* data);

    static void initializeKeyOnceHelper();

    static void initializeKeyOnce();

    ThreadIdentifier m_identifier;

    bool m_isDestroyedOnce;

    static pthread_key_t m_key;

};

} // namespace WTF

#endif // ThreadIdentifierDataPthreads_h