hvirtual/guicast/mutex.C

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#ifndef NO_GUICAST
#include "bcsignals.h"
#endif
#include "mutex.h"

Mutex::Mutex(char *title, int recursive)
{
        this->title = title;
        pthread_mutexattr_t attr;
        pthread_mutexattr_init(&attr);
        pthread_mutex_init(&mutex, &attr);
        pthread_mutex_init(&recursive_lock, &attr);
        count = 0;
        this->recursive = recursive;
        thread_id = 0;
        thread_id_valid = 0;
}

Mutex::~Mutex()
{
        pthread_mutex_destroy(&mutex);
        pthread_mutex_destroy(&recursive_lock);
#ifndef NO_GUICAST
        UNSET_ALL_LOCKS(this);
#endif
}
        
int Mutex::lock(char *location)
{
// Test recursive owner and give up if we already own it
        if(recursive)
        {
                pthread_mutex_lock(&recursive_lock);
                if(thread_id_valid && pthread_self() == thread_id) 
                {
                        count++;
                        pthread_mutex_unlock(&recursive_lock);
                        return 0;
                }
                pthread_mutex_unlock(&recursive_lock);
        }


#ifndef NO_GUICAST
        SET_LOCK(this, title, location);
#endif
        if(pthread_mutex_lock(&mutex)) perror("Mutex::lock");



// Update recursive status for the first lock
        if(recursive)
        {
                pthread_mutex_lock(&recursive_lock);
                count = 1;
                thread_id = pthread_self();
                thread_id_valid = 1;
                pthread_mutex_unlock(&recursive_lock);
        }
        else
        {
                count = 1;
        }


#ifndef NO_GUICAST
        SET_LOCK2
#endif
        return 0;
}

int Mutex::unlock()
{
// Remove from recursive status
        if(recursive)
        {
                pthread_mutex_lock(&recursive_lock);
                count--;
// Still locked
                if(count > 0) 
                {
                        pthread_mutex_unlock(&recursive_lock);
                        return 0;
                }
// Not owned anymore
                thread_id = 0;
                thread_id_valid = 0;
                pthread_mutex_unlock(&recursive_lock);
        }
        else
                count = 0;


#ifndef NO_GUICAST
        UNSET_LOCK(this);
#endif

        if(pthread_mutex_unlock(&mutex)) perror("Mutex::unlock");
        return 0;
}

int Mutex::trylock()
{
        return pthread_mutex_trylock(&mutex);
}

int Mutex::is_locked()
{
        return count;
}

int Mutex::reset()
{
        pthread_mutex_destroy(&mutex);
        pthread_mutexattr_t attr;
        pthread_mutexattr_init(&attr);
        pthread_mutex_init(&mutex, &attr);
        count = 0;
        thread_id = 0;
        thread_id_valid = 0;
#ifndef NO_GUICAST
        UNSET_ALL_LOCKS(this)
#endif
        return 0;
}

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