/* GNU Objective C Runtime Thread Interface
   Copyright (C) 1996, 1997, 2009 Free Software Foundation, Inc.
   Contributed by Galen C. Hunt (gchunt@cs.rochester.edu)

This file is part of GCC.

GCC 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 3, or (at your option) any later version.

GCC 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.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */


#include <pthread.h>
#include "objc/thr.h"
#include "objc/runtime.h"

/* Key structure for maintaining thread specific storage */
static pthread_key_t _objc_thread_storage;

/* Backend initialization functions */

/* Initialize the threads subsystem. */
int
__objc_init_thread_system(void)
{
  /* Initialize the thread storage key */
  return pthread_keycreate(&_objc_thread_storage, NULL);
}

/* Close the threads subsystem. */
int
__objc_close_thread_system(void)
{
  /* Destroy the thread storage key */
  /* Not implemented yet */
  /* return pthread_key_delete(&_objc_thread_storage); */
  return 0;
}

/* Backend thread functions */

/* Create a new thread of execution. */
objc_thread_t
__objc_thread_detach(void (*func)(void *arg), void *arg)
{
  objc_thread_t thread_id;
  pthread_t new_thread_handle;

  if (pthread_create(&new_thread_handle, pthread_attr_default,
		     (void *)func, arg) == 0)
    {
      /* ??? May not work! (64bit) */
      thread_id = *(objc_thread_t *)&new_thread_handle; 
      pthread_detach(&new_thread_handle);     /* Fully detach thread.     */
    }
  else
    thread_id = NULL;
  
  return thread_id;
}

/* Set the current thread's priority. */
int
__objc_thread_set_priority(int priority)
{
  int sys_priority = 0;

  switch (priority)
    {
    case OBJC_THREAD_INTERACTIVE_PRIORITY:
      sys_priority = (PRI_FG_MIN_NP + PRI_FG_MAX_NP) / 2;
      break;
    default:
    case OBJC_THREAD_BACKGROUND_PRIORITY:
      sys_priority = (PRI_BG_MIN_NP + PRI_BG_MAX_NP) / 2;
      break;
    case OBJC_THREAD_LOW_PRIORITY:
      sys_priority = (PRI_BG_MIN_NP + PRI_BG_MAX_NP) / 2;
      break;
    }
    
  /* Change the priority. */
  if (pthread_setprio(pthread_self(), sys_priority) >= 0)
    return 0;
  else
    /* Failed */
    return -1;
}

/* Return the current thread's priority. */
int
__objc_thread_get_priority(void)
{
  int sys_priority;
    
  if ((sys_priority = pthread_getprio(pthread_self())) >= 0) {
    if (sys_priority >= PRI_FG_MIN_NP && sys_priority <= PRI_FG_MAX_NP)
      return OBJC_THREAD_INTERACTIVE_PRIORITY;
    if (sys_priority >= PRI_BG_MIN_NP && sys_priority <= PRI_BG_MAX_NP)
      return OBJC_THREAD_BACKGROUND_PRIORITY;
    return OBJC_THREAD_LOW_PRIORITY;
  }

  /* Failed */
  return -1;
}

/* Yield our process time to another thread. */
void
__objc_thread_yield(void)
{
  pthread_yield();
}

/* Terminate the current thread. */
int
__objc_thread_exit(void)
{
  /* exit the thread */
  pthread_exit(&__objc_thread_exit_status);

  /* Failed if we reached here */
  return -1;
}

/* Returns an integer value which uniquely describes a thread. */
objc_thread_t
__objc_thread_id(void)
{
  pthread_t self = pthread_self();

  return (objc_thread_t) pthread_getunique_np (&self);
}

/* Sets the thread's local storage pointer. */
int
__objc_thread_set_data(void *value)
{
  return pthread_setspecific(_objc_thread_storage, value);
}

/* Returns the thread's local storage pointer. */
void *
__objc_thread_get_data(void)
{
  void *value = NULL;

  if ( !(pthread_getspecific(_objc_thread_storage, &value)) )
    return value;

  return NULL;
}

/* Backend mutex functions */

/* Allocate a mutex. */
int
__objc_mutex_allocate(objc_mutex_t mutex)
{
  if (pthread_mutex_init((pthread_mutex_t *)(&(mutex->backend)), 
			 pthread_mutexattr_default))
    return -1;
  else
    return 0;
}

/* Deallocate a mutex. */
int
__objc_mutex_deallocate(objc_mutex_t mutex)
{
  if (pthread_mutex_destroy((pthread_mutex_t *)(&(mutex->backend))))
    return -1;
  else
    return 0;
}

/* Grab a lock on a mutex. */
int
__objc_mutex_lock(objc_mutex_t mutex)
{
  return pthread_mutex_lock((pthread_mutex_t *)(&(mutex->backend)));
}

/* Try to grab a lock on a mutex. */
int
__objc_mutex_trylock(objc_mutex_t mutex)
{
  if (pthread_mutex_trylock((pthread_mutex_t *)(&(mutex->backend))) != 1)
    return -1;
  else
    return 0;
}

/* Unlock the mutex */
int
__objc_mutex_unlock(objc_mutex_t mutex)
{
  return pthread_mutex_unlock((pthread_mutex_t *)(&(mutex->backend)));
}

/* Backend condition mutex functions */

/* Allocate a condition. */
int
__objc_condition_allocate(objc_condition_t condition)
{
  /* Unimplemented. */
  return -1;

  /*
  if (pthread_cond_init((pthread_cond_t *)(&(condition->backend)), NULL))
    return -1;
  else
    return 0;
    */
}

/* Deallocate a condition. */
int
__objc_condition_deallocate(objc_condition_t condition)
{
  /* Unimplemented. */
  return -1;

  /*
  return pthread_cond_destroy((pthread_cond_t *)(&(condition->backend)));
  */
}

/* Wait on the condition */
int
__objc_condition_wait(objc_condition_t condition, objc_mutex_t mutex)
{
  /* Unimplemented. */
  return -1;

  /*
  return pthread_cond_wait((pthread_cond_t *)(&(condition->backend)),
			   (pthread_mutex_t *)(&(mutex->backend)));
			   */
}

/* Wake up all threads waiting on this condition. */
int
__objc_condition_broadcast(objc_condition_t condition)
{
  /* Unimplemented. */
  return -1;

  /*
  return pthread_cond_broadcast((pthread_cond_t *)(&(condition->backend)));
  */
}

/* Wake up one thread waiting on this condition. */
int
__objc_condition_signal(objc_condition_t condition)
{
  /* Unimplemented. */
  return -1;

  /*
  return pthread_cond_signal((pthread_cond_t *)(&(condition->backend)));
  */
}

/* End of File */