ThreadUtil.h

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/* Copyright (C) 2010 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDED_THREADUTIL
#define INCLUDED_THREADUTIL

#include "lib/posix/posix_pthread.h"

#ifdef DEBUG_LOCKS

#define LOCK_MUTEX(_mutex) STMT( \
    printf("pthread_mutex_lock: 1 %p [pid:%d]\n", _mutex, pthread_self()); \
    pthread_mutex_lock(_mutex); \
    printf("pthread_mutex_lock: 2 %p [pid:%d]\n", _mutex, pthread_self()) \
)
#define UNLOCK_MUTEX(_mutex) STMT( \
    pthread_mutex_unlock(_mutex); \
    printf("pthread_mutex_unlock: %p [pid:%d]\n", _mutex, pthread_self()) \
)

#else

#define LOCK_MUTEX(_mutex) pthread_mutex_lock(_mutex)
#define UNLOCK_MUTEX(_mutex) pthread_mutex_unlock(_mutex)

#endif

/**
 * A non-recursive mutual exclusion lock.
 */
class CMutex
{
    NONCOPYABLE(CMutex);

    friend class CScopeLock;

public:
    CMutex()
    {
        int ret = pthread_mutex_init(&m_Mutex, NULL);
        ENSURE(ret == 0);
    }
    
    ~CMutex()
    {
        int ret = pthread_mutex_destroy(&m_Mutex);
        ENSURE(ret == 0);
    }

private:
    pthread_mutex_t m_Mutex;
};

/**
 * Locks a CMutex over this object's lifetime.
 * The mutexes are non-recursive - a single thread locking a mutex more than once
 * results in undefined behaviour.
 */
class CScopeLock
{
    NONCOPYABLE(CScopeLock);

public:
    CScopeLock(pthread_mutex_t* mutex) :
        m_Mutex(mutex)
    {
        LOCK_MUTEX(m_Mutex);
    }

    CScopeLock(CMutex& mutex) :
        m_Mutex(&mutex.m_Mutex)
    {
        LOCK_MUTEX(m_Mutex);
    }

    ~CScopeLock()
    {
        UNLOCK_MUTEX(m_Mutex);
    }

private:
    pthread_mutex_t* m_Mutex;
};


namespace ThreadUtil
{

/**
 * Returns whether the current thread is the 'main' thread
 * (i.e. matches an earlier call to SetMainThread).
 */
bool IsMainThread();

/**
 * Set the current thread as the 'main' thread.
 * (This is called during engine initialisation.)
 */
void SetMainThread();

}

#endif // INCLUDED_THREADUTIL