critical_section.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_CRITICAL_SECTION_H_
#define _TBB_CRITICAL_SECTION_H_

#if _WIN32||_WIN64
#include <windows.h>
#else
#include <pthread.h>
#include <errno.h>
#endif  // _WIN32||WIN64

#include "tbb_stddef.h"
#include "tbb_thread.h"
#include "tbb_exception.h"

#include "tbb_profiling.h"

namespace tbb {

    namespace internal {
class critical_section_v4 : internal::no_copy {
#if _WIN32||_WIN64
    CRITICAL_SECTION my_impl;
#else
    pthread_mutex_t my_impl;
#endif
    tbb_thread::id my_tid;
public:

    void __TBB_EXPORTED_METHOD internal_construct();

    critical_section_v4() { 
#if _WIN32||_WIN64
        InitializeCriticalSection(&my_impl);
#else
        pthread_mutex_init(&my_impl, NULL);
#endif
        internal_construct();
    }

    ~critical_section_v4() {
        __TBB_ASSERT(my_tid == tbb_thread::id(), "Destroying a still-held critical section");
#if _WIN32||_WIN64
        DeleteCriticalSection(&my_impl); 
#else
        pthread_mutex_destroy(&my_impl);
#endif
    }

    class scoped_lock : internal::no_copy {
    private:
        critical_section_v4 &my_crit;
    public:
        scoped_lock( critical_section_v4& lock_me) :my_crit(lock_me) {
            my_crit.lock();
        }

        ~scoped_lock() {
            my_crit.unlock();
        }
    };

    void lock() { 
        tbb_thread::id local_tid = this_tbb_thread::get_id();
        if(local_tid == my_tid) throw_exception( eid_improper_lock );
#if _WIN32||_WIN64
        EnterCriticalSection( &my_impl );
#else
        int rval = pthread_mutex_lock(&my_impl);
        __TBB_ASSERT_EX(!rval, "critical_section::lock: pthread_mutex_lock failed");
#endif
        __TBB_ASSERT(my_tid == tbb_thread::id(), NULL);
        my_tid = local_tid;
    }

    bool try_lock() {
        bool gotlock;
        tbb_thread::id local_tid = this_tbb_thread::get_id();
        if(local_tid == my_tid) return false;
#if _WIN32||_WIN64
        gotlock = TryEnterCriticalSection( &my_impl ) != 0;
#else
        int rval = pthread_mutex_trylock(&my_impl);
        // valid returns are 0 (locked) and [EBUSY]
        __TBB_ASSERT(rval == 0 || rval == EBUSY, "critical_section::trylock: pthread_mutex_trylock failed");
        gotlock = rval == 0;
#endif
        if(gotlock)  {
            my_tid = local_tid;
        }
        return gotlock;
    }

    void unlock() {
        __TBB_ASSERT(this_tbb_thread::get_id() == my_tid, "thread unlocking critical_section is not thread that locked it");
        my_tid = tbb_thread::id();
#if _WIN32||_WIN64
        LeaveCriticalSection( &my_impl );
#else
        int rval = pthread_mutex_unlock(&my_impl);
        __TBB_ASSERT_EX(!rval, "critical_section::unlock: pthread_mutex_unlock failed");
#endif
    }

    static const bool is_rw_mutex = false;
    static const bool is_recursive_mutex = false;
    static const bool is_fair_mutex = true;
}; // critical_section_v4
} // namespace internal
typedef internal::critical_section_v4 critical_section;

__TBB_DEFINE_PROFILING_SET_NAME(critical_section)
} // namespace tbb
#endif  // _TBB_CRITICAL_SECTION_H_