/* Conditions */
/* Copyright (C) 2008  Emmanuel Varoquaux

   This file is part of XOS.

   This program 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 of the License, or
   (at your option) any later version.

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>. */

#include "sched.h"
#include "proc_queue.h"
#include "proc_struct.h"

#include <asm.h>
#include <enums.h>

void condition_init(struct condition_struct *condition)
{
  proc_queue_init(&condition->proc_queue);
}

void condition_wait(struct condition_struct *condition)
{
  int intr;

  disable_intr(intr);
  sched_remove(current);
  current->state = PS_WAITING_UNINTERRUPTIBLE;
  current->condition = condition;
  proc_queue_push(&condition->proc_queue, current);
  schedule();
  restore_intr(intr);
}

/* Retourne true si le processus a ete reveille par condition_signal(), false
 * si l'attente a ete interrompue. */
int condition_wait_interruptible(struct condition_struct *condition)
{
  int retval;
  int intr;

  disable_intr(intr);
  sched_remove(current);
  current->state = PS_WAITING_INTERRUPTIBLE;
  current->condition = condition;
  proc_queue_push(&condition->proc_queue, current);
  schedule();
  retval = !current->interrupted;
  restore_intr(intr);
  return retval;
}

/* Reveille, s'il en existe, un processus en attente sur la condition. */
void condition_signal(struct condition_struct *condition)
{
  int intr;
  struct proc_struct *proc;

  disable_intr(intr);
  if ((proc = proc_queue_pop(&condition->proc_queue))) {
    proc->state = PS_RUNNING;
    proc->interrupted = 0;
    sched_add(proc);
  }
  restore_intr(intr);
}

/* Reveille tous les processus en attente sur la condition. */
void condition_signal_all(struct condition_struct *condition)
{
  int intr;
  struct proc_struct *proc;

  disable_intr(intr);
  while ((proc = proc_queue_pop(&condition->proc_queue))) {
    proc->state = PS_RUNNING;
    proc->interrupted = 0;
    sched_add(proc);
  }
  restore_intr(intr);
}

/* Interrompt l'attente du processus, qui doit etre dans l'etat
 * PS_WAITING_INTERRUPTIBLE. */
void condition_interrupt(struct proc_struct *proc)
{
  int intr;

  disable_intr(intr);
  proc_queue_remove(&proc->condition->proc_queue, proc);
  proc->state = PS_RUNNING;
  proc->interrupted = 1;
  sched_add(proc);
  restore_intr(intr);
}