/*

  silcschedule_i.h.

  Author: Pekka Riikonen <priikone@silcnet.org>

  Copyright (C) 2001 - 2006 Pekka Riikonen

  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; version 2 of the License.

  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.

*/

#ifndef SILCSCHEDULE_I_H
#define SILCSCHEDULE_I_H

#ifndef SILCSCHEDULE_H
#error "Do not include this header directly"
#endif

#include "silchashtable.h"
#include "silclist.h"

/* Task header */
struct SilcTaskStruct {
  SilcTaskCallback callback;
  void *context;
  unsigned int type    : 1;	/* 0 = fd, 1 = timeout */
  unsigned int valid   : 1;	/* Set if task is valid */
};

/* Timeout task */
typedef struct SilcTaskTimeoutStruct {
  struct SilcTaskStruct header;
  struct SilcTaskTimeoutStruct *next;
  struct timeval timeout;
} *SilcTaskTimeout;

/* Fd task */
typedef struct {
  struct SilcTaskStruct header;
  unsigned int events  : 15;
  unsigned int revents : 15;
  SilcUInt32 fd;
} *SilcTaskFd;

/* Scheduler context */
struct SilcScheduleStruct {
  void *internal;
  void *app_context;		   /* Application specific context */
  SilcHashTable fd_queue;	   /* FD task queue */
  SilcList timeout_queue;	   /* Timeout queue */
  SilcList free_tasks;		   /* Timeout task freelist */
  SilcMutex lock;		   /* Scheduler lock */
  struct timeval timeout;	   /* Current timeout */
  unsigned int max_tasks     : 28; /* Max FD tasks */
  unsigned int has_timeout   : 1;  /* Set if timeout is set */
  unsigned int valid         : 1;  /* Set if scheduler is valid */
  unsigned int signal_tasks  : 1;  /* Set if to dispatch signals */
};

/* Locks. These also blocks signals that we care about and thus guarantee
   that while we are in scheduler no signals can happen.  This way we can
   synchronise signals with SILC Scheduler. */
#define SILC_SCHEDULE_LOCK(schedule)				\
do {								\
  schedule_ops.signals_block(schedule, schedule->internal);	\
  silc_mutex_lock(schedule->lock);				\
} while (0)
#define SILC_SCHEDULE_UNLOCK(schedule)				\
do {								\
  silc_mutex_unlock(schedule->lock);				\
  schedule_ops.signals_unblock(schedule, schedule->internal);	\
} while (0)

/* Platform specific scheduler operations */
typedef struct {
  /* Initializes the platform specific scheduler.  This for example initializes
     the wakeup mechanism of the scheduler.  In multi-threaded environment
     the scheduler needs to be wakenup when tasks are added or removed from
     the task queues.  Returns context to the platform specific scheduler. */
  void *(*init)(SilcSchedule schedule, void *app_context);

  /* Uninitializes the platform specific scheduler context. */
  void (*uninit)(SilcSchedule schedule, void *context);

  /* System specific select(). Returns same values as normal select(). */
  int (*select)(SilcSchedule schedule, void *context);

  /* Wakes up the scheduler. This is platform specific routine */
  void (*wakeup)(SilcSchedule schedule, void *context);

  /* Register signal */
  void (*signal_register)(SilcSchedule schedule, void *context,
			  SilcUInt32 signal, SilcTaskCallback callback,
			  void *callback_context);

  /* Unregister signal */
  void (*signal_unregister)(SilcSchedule schedule, void *context,
			    SilcUInt32 signal);

  /* Call all signals */
  void (*signals_call)(SilcSchedule schedule, void *context);

  /* Block registered signals in scheduler. */
  void (*signals_block)(SilcSchedule schedule, void *context);

  /* Unblock registered signals in schedule. */
  void (*signals_unblock)(SilcSchedule schedule, void *context);
} SilcScheduleOps;

/* The generic function to add any type of task to the scheduler.  This
   used to be exported as is to application, but now they should use the
   macro wrappers defined in silcschedule.h.  For Fd task the timeout must
   be zero, for timeout task the timeout must not be zero, for signal task
   the fd argument is the signal. */
SilcTask silc_schedule_task_add(SilcSchedule schedule, SilcUInt32 fd,
				SilcTaskCallback callback, void *context,
				long seconds, long useconds,
				SilcTaskType type);

#ifdef SILC_DIST_INPLACE
/* Print scheduler statistics to stdout. */
void silc_schedule_stats(SilcSchedule schedule);
#endif /* SILC_DIST_INPLACE */

#endif /* SILCSCHEDULE_I_H */