mutex.h

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/*
    Copyright 2005-2010 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks.

    Threading Building Blocks is free software; you can redistribute it
    and/or modify it under the terms of the GNU General Public License
    version 2 as published by the Free Software Foundation.

    Threading Building Blocks 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Threading Building Blocks; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    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 General Public License.
*/

#ifndef __TBB_mutex_H
#define __TBB_mutex_H

#if _WIN32||_WIN64
    #include <windows.h>
    #if !defined(_WIN32_WINNT)
    // The following Windows API function is declared explicitly;
    // otherwise any user would have to specify /D_WIN32_WINNT=0x0400
    extern "C" BOOL WINAPI TryEnterCriticalSection( LPCRITICAL_SECTION );
    #endif
#else /* if not _WIN32||_WIN64 */
    #include <pthread.h>
#endif /* _WIN32||_WIN64 */

#include <new>
#include "aligned_space.h"
#include "tbb_stddef.h"
#include "tbb_profiling.h"

namespace tbb {


class mutex {
public:
    mutex() {
#if TBB_USE_ASSERT || TBB_USE_THREADING_TOOLS
    internal_construct();
#else
  #if _WIN32||_WIN64
        InitializeCriticalSection(&impl);
  #else
        int error_code = pthread_mutex_init(&impl,NULL);
        if( error_code )
            tbb::internal::handle_perror(error_code,"mutex: pthread_mutex_init failed");
  #endif /* _WIN32||_WIN64*/
#endif /* TBB_USE_ASSERT */
    };

    ~mutex() {
#if TBB_USE_ASSERT
        internal_destroy();
#else
  #if _WIN32||_WIN64
        DeleteCriticalSection(&impl);
  #else
        pthread_mutex_destroy(&impl); 

  #endif /* _WIN32||_WIN64 */
#endif /* TBB_USE_ASSERT */
    };

    class scoped_lock;
    friend class scoped_lock;


    class scoped_lock : internal::no_copy {
    public:
        scoped_lock() : my_mutex(NULL) {};

        scoped_lock( mutex& mutex ) {
            acquire( mutex );
        }

        ~scoped_lock() {
            if( my_mutex ) 
                release();
        }

        void acquire( mutex& mutex ) {
#if TBB_USE_ASSERT
            internal_acquire(mutex);
#else
            mutex.lock();
            my_mutex = &mutex;
#endif /* TBB_USE_ASSERT */
        }

        bool try_acquire( mutex& mutex ) {
#if TBB_USE_ASSERT
            return internal_try_acquire (mutex);
#else
            bool result = mutex.try_lock();
            if( result )
                my_mutex = &mutex;
            return result;
#endif /* TBB_USE_ASSERT */
        }

        void release() {
#if TBB_USE_ASSERT
            internal_release ();
#else
            my_mutex->unlock();
            my_mutex = NULL;
#endif /* TBB_USE_ASSERT */
        }

    private:
        mutex* my_mutex;

        void __TBB_EXPORTED_METHOD internal_acquire( mutex& m );

        bool __TBB_EXPORTED_METHOD internal_try_acquire( mutex& m );

        void __TBB_EXPORTED_METHOD internal_release();

        friend class mutex;
    };

    // Mutex traits
    static const bool is_rw_mutex = false;
    static const bool is_recursive_mutex = false;
    static const bool is_fair_mutex = false;

    // ISO C++0x compatibility methods

    void lock() {
#if TBB_USE_ASSERT
        aligned_space<scoped_lock,1> tmp;
        new(tmp.begin()) scoped_lock(*this);
#else
  #if _WIN32||_WIN64
        EnterCriticalSection(&impl);
  #else
        pthread_mutex_lock(&impl);
  #endif /* _WIN32||_WIN64 */
#endif /* TBB_USE_ASSERT */
    }


    bool try_lock() {
#if TBB_USE_ASSERT
        aligned_space<scoped_lock,1> tmp;
        scoped_lock& s = *tmp.begin();
        s.my_mutex = NULL;
        return s.internal_try_acquire(*this);
#else
  #if _WIN32||_WIN64
        return TryEnterCriticalSection(&impl)!=0;
  #else
        return pthread_mutex_trylock(&impl)==0;
  #endif /* _WIN32||_WIN64 */
#endif /* TBB_USE_ASSERT */
    }

    void unlock() {
#if TBB_USE_ASSERT
        aligned_space<scoped_lock,1> tmp;
        scoped_lock& s = *tmp.begin();
        s.my_mutex = this;
        s.internal_release();
#else
  #if _WIN32||_WIN64
        LeaveCriticalSection(&impl);
  #else
        pthread_mutex_unlock(&impl);
  #endif /* _WIN32||_WIN64 */
#endif /* TBB_USE_ASSERT */
    }

  #if _WIN32||_WIN64
    typedef LPCRITICAL_SECTION native_handle_type;
  #else
    typedef pthread_mutex_t* native_handle_type;
  #endif
    native_handle_type native_handle() { return (native_handle_type) &impl; }

    enum state_t {
        INITIALIZED=0x1234,
        DESTROYED=0x789A,
        HELD=0x56CD
    };
private:
#if _WIN32||_WIN64
    CRITICAL_SECTION impl;    
    enum state_t state;
#else
    pthread_mutex_t impl;
#endif /* _WIN32||_WIN64 */

    void __TBB_EXPORTED_METHOD internal_construct();

    void __TBB_EXPORTED_METHOD internal_destroy();

#if _WIN32||_WIN64
public:
    void set_state( state_t to ) { state = to; }
#endif
};

__TBB_DEFINE_PROFILING_SET_NAME(mutex)

} // namespace tbb 

#endif /* __TBB_mutex_H */