text: /*
   * Copyright 2009-2012 Niels Provos and Nick Mathewson
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. 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.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  #include "event2/event-config.h"
  #include "evconfig-private.h"
  
  /* With glibc we need to define _GNU_SOURCE to get PTHREAD_MUTEX_RECURSIVE.
   * This comes from evconfig-private.h
   */
  #include <pthread.h>
  
  struct event_base;
  #include "event2/thread.h"
  
  #include <stdlib.h>
  #include <string.h>
  #include "mm-internal.h"
  #include "evthread-internal.h"
  
  static pthread_mutexattr_t attr_default;
  static pthread_mutexattr_t attr_recursive;
  
  static pthread_mutex_t once_init_lock = PTHREAD_MUTEX_INITIALIZER;
  static int once_init = 0;
  
  static void *
  evthread_posix_lock_alloc(unsigned locktype)
  {
  	pthread_mutexattr_t *attr = &attr_default;
  	pthread_mutex_t *lock = mm_malloc(sizeof(pthread_mutex_t));
  	if (!lock)
  		return NULL;
  	if (locktype & EVTHREAD_LOCKTYPE_RECURSIVE)
  		attr = &attr_recursive;
  	if (pthread_mutex_init(lock, attr)) {
  		mm_free(lock);
  		return NULL;
  	}
  	return lock;
  }
  
  static void
  evthread_posix_lock_free(void *lock_, unsigned locktype)
  {
  	pthread_mutex_t *lock = lock_;
  	pthread_mutex_destroy(lock);
  	mm_free(lock);
  }
  
  static int
  evthread_posix_lock(unsigned mode, void *lock_)
  {
  	pthread_mutex_t *lock = lock_;
  	if (mode & EVTHREAD_TRY)
  		return pthread_mutex_trylock(lock);
  	else
  		return pthread_mutex_lock(lock);
  }
  
  static int
  evthread_posix_unlock(unsigned mode, void *lock_)
  {
  	pthread_mutex_t *lock = lock_;
  	return pthread_mutex_unlock(lock);
  }
  
  static unsigned long
  evthread_posix_get_id(void)
  {
  	union {
  		pthread_t thr;
  #if EVENT__SIZEOF_PTHREAD_T > EVENT__SIZEOF_LONG
  		ev_uint64_t id;
  #else
  		unsigned long id;
  #endif
  	} r;
  #if EVENT__SIZEOF_PTHREAD_T < EVENT__SIZEOF_LONG
  	memset(&r, 0, sizeof(r));
  #endif
  	r.thr = pthread_self();
  	return (unsigned long)r.id;
  }
  
  static void *
  evthread_posix_cond_alloc(unsigned condflags)
  {
  	pthread_cond_t *cond = mm_malloc(sizeof(pthread_cond_t));
  	if (!cond)
  		return NULL;
  	if (pthread_cond_init(cond, NULL)) {
  		mm_free(cond);
  		return NULL;
  	}
  	return cond;
  }
  
  static void
  evthread_posix_cond_free(void *cond_)
  {
  	pthread_cond_t *cond = cond_;
  	pthread_cond_destroy(cond);
  	mm_free(cond);
  }
  
  static int
  evthread_posix_cond_signal(void *cond_, int broadcast)
  {
  	pthread_cond_t *cond = cond_;
  	int r;
  	if (broadcast)
  		r = pthread_cond_broadcast(cond);
  	else
  		r = pthread_cond_signal(cond);
  	return r ? -1 : 0;
  }
  
  static int
  evthread_posix_cond_wait(void *cond_, void *lock_, const struct timeval *tv)
  {
  	int r;
  	pthread_cond_t *cond = cond_;
  	pthread_mutex_t *lock = lock_;
  
  	if (tv) {
  		struct timeval now, abstime;
  		struct timespec ts;
  		evutil_gettimeofday(&now, NULL);
  		evutil_timeradd(&now, tv, &abstime);
  		ts.tv_sec = abstime.tv_sec;
  		ts.tv_nsec = abstime.tv_usec*1000;
  		r = pthread_cond_timedwait(cond, lock, &ts);
  		if (r == ETIMEDOUT)
  			return 1;
  		else if (r)
  			return -1;
  		else
  			return 0;
  	} else {
  		r = pthread_cond_wait(cond, lock);
  		return r ? -1 : 0;
  	}
  }
  
  int
  evthread_use_pthreads_with_flags(int flags)
  {
  	struct evthread_lock_callbacks cbs = {
  		EVTHREAD_LOCK_API_VERSION,
  		EVTHREAD_LOCKTYPE_RECURSIVE,
  		evthread_posix_lock_alloc,
  		evthread_posix_lock_free,
  		evthread_posix_lock,
  		evthread_posix_unlock
  	};
  	struct evthread_condition_callbacks cond_cbs = {
  		EVTHREAD_CONDITION_API_VERSION,
  		evthread_posix_cond_alloc,
  		evthread_posix_cond_free,
  		evthread_posix_cond_signal,
  		evthread_posix_cond_wait
  	};
  
  	pthread_mutex_lock(&once_init_lock);
  	if (once_init == 1) {
  		pthread_mutex_unlock(&once_init_lock);
  		return 0;
  	}
  
  	if (pthread_mutexattr_init(&attr_default)) 
  		goto error;
  
  	/* Set ourselves up to get recursive locks. */
  	if (pthread_mutexattr_init(&attr_recursive))
  		goto error;
  	if (pthread_mutexattr_settype(&attr_recursive, PTHREAD_MUTEX_RECURSIVE))
  		goto error;
  
  	if (flags & EVTHREAD_PTHREAD_PRIO_INHERIT) {
  #ifdef EVENT__HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL
  		/* Set up priority inheritance */
  		if (pthread_mutexattr_setprotocol(&attr_default, PTHREAD_PRIO_INHERIT))
  			goto error;
  		if (pthread_mutexattr_setprotocol(&attr_recursive, PTHREAD_PRIO_INHERIT))
  			goto error;
  #else
  		goto error;
  #endif
  	}
  
  	evthread_set_lock_callbacks(&cbs);
  	evthread_set_condition_callbacks(&cond_cbs);
  	evthread_set_id_callback(evthread_posix_get_id);
  	once_init = 1;
  
  	return 0;
  error:
  	pthread_mutex_unlock(&once_init_lock);
  	return -1;
  }
  
  int
  evthread_use_pthreads(void)
  {
  	return evthread_use_pthreads_with_flags(0);
  }
  