/* -*-C-*-

$Id: os2msg.h,v 1.15 1999/01/02 06:11:34 cph Exp $

Copyright (c) 1994-1999 Massachusetts Institute of Technology

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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifndef SCM_OS2MSG_H
#define SCM_OS2MSG_H

typedef enum
{
  /* This is sent to acknowledge that the other end of a qid pair has
     been opened.  Sometimes it is necessary to wait until the
     connection is established before proceeding.  */
  mt_init,

  /* This is sent by a "readahead" thread whenever it has some data to
     give to the other end of the connection.  These messages are
     generated asynchronously whenever the readahead is available.  */
  mt_readahead,

  /* This is sent by the receiver of a readahead message.  It is used
     to regulate the amount of readahead in the connection.
     Typically, the readahead thread won't generate any more readahead
     messages until the readahead_ack is received.  */
  mt_readahead_ack,

  /* This is a console interrupt event.  It is generated automatically
     by the console readahead thread, and causes a Scheme character
     interrupt to be signalled in the interrupt-code register.  */
  mt_console_interrupt,

  /* This is a timer interrupt event.  It is generated automatically
     by the timer thread when the timer is active.  */
  mt_timer_event,
  
  /* This event signals the termination of a child process.  It is
     generated automatically by the thread that monitors child
     processes.  */
  mt_child_death,

  /* These are error messages.  They are sent as a reply to a request
     when an error is generated during the processing of the request.  */
  mt_error,
  mt_syscall_error,

  /* This is a generic reply that is used to acknowledge requests that
     return no meaningful data other than that they have completed.  */
  mt_generic_reply,

  /* This machine-generated file contains most of the PM message types.  */
#include "os2pm-mt.h"

  /* These are messages that command the PM thread to perform specific
     actions.  A command that does not have a specific reply type will
     receive a generic reply when the PM code is configured to do
     handshaking; normally such a command has no reply.  */
  mt_window_pos_request,	/* request position of window's frame */
  mt_window_pos_reply,
  mt_window_size_request,	/* request size of window's client area */
  mt_window_size_reply,
  mt_window_frame_size_request,	/* request size of window's frame */
  mt_window_frame_size_reply,

  /* These are also PM thread commands, but they operate on
     presentation spaces rather than on windows.  */
  mt_ps_set_bitmap_request,	/* associate a bitmap with a memory PS */
  mt_ps_set_bitmap_reply,

  /* These are messages that are automatically generated by the PM
     thread when the corresponding events occur.  */
  mt_pm_event,			/* undecoded PM input event */
  mt_paint_event,		/* window needs painting */

  /* This requests the thread on the other end of the connection to
     kill itself.  At present this request is not used.  */
  mt_kill_request,
  mt_supremum
} msg_type_t;
#define MSG_TYPE_SUP ((unsigned int) mt_supremum)
#define MSG_TYPE_MAX (MSG_TYPE_SUP - 1)

typedef unsigned char qid_t;
#define QID_MAX (UCHAR_MAX - 1)
#define QID_NONE UCHAR_MAX

typedef unsigned short msg_length_t;
#define MSG_LENGTH_MAX USHRT_MAX

/* Fields of message header:
   type: msg_type_t identifying the type of message
   sender: qid identifying the message sender (used for replies)
   */

#define DECLARE_MSG_HEADER_FIELDS					\
  msg_type_t _msg_type;							\
  qid_t _msg_sender

typedef struct
{
  DECLARE_MSG_HEADER_FIELDS;
} msg_t;

#define _MSG(m) ((msg_t *) (m))
#define MSG_TYPE(m) ((_MSG (m)) -> _msg_type)
#define MSG_SENDER(m) ((_MSG (m)) -> _msg_sender)

typedef enum
{
  tqt_std,
  tqt_scm,
  tqt_pm
} tqueue_type_t;

typedef struct
{
  tqueue_type_t type;
} tqueue_t;
#define TQUEUE_TYPE(q) (((tqueue_t *) (q)) -> type)

typedef msg_t * (* qid_receive_filter_t) (msg_t *);

typedef enum { mat_not_available, mat_available, mat_interrupt } msg_avail_t;

extern tqueue_t * OS2_scheme_tqueue;
extern qid_t OS2_interrupt_qid;
extern char OS2_scheme_tqueue_avail_map [QID_MAX + 1];

extern void OS2_make_qid_pair (qid_t *, qid_t *);
extern void OS2_open_qid (qid_t, tqueue_t *);
extern int OS2_qid_openp (qid_t);
extern void OS2_close_qid (qid_t);
extern tqueue_t * OS2_qid_tqueue (qid_t);
extern qid_t OS2_qid_twin (qid_t);
extern void OS2_close_qid_pair (qid_t);
extern void OS2_set_qid_receive_filter (qid_t, qid_receive_filter_t);
extern msg_length_t OS2_message_type_length (msg_type_t);
extern void OS2_set_message_type_length (msg_type_t, msg_length_t);
extern msg_t * OS2_create_message_1 (msg_type_t, msg_length_t);
extern void OS2_destroy_message (msg_t *);
extern void OS2_send_message (qid_t, msg_t *);
extern msg_t * OS2_receive_message (qid_t, int, int);
extern msg_avail_t OS2_message_availablep (qid_t, int);
extern msg_t * OS2_wait_for_message (qid_t, msg_type_t);
extern msg_t * OS2_message_transaction (qid_t, msg_t *, msg_type_t);
extern void OS2_unread_message (qid_t, msg_t *);
extern int OS2_tqueue_select (tqueue_t *, int);
extern tqueue_t * OS2_make_std_tqueue (void);
extern void OS2_close_std_tqueue (tqueue_t *);

extern void * OS2_create_msg_fifo (void);
void OS2_destroy_msg_fifo (void *);
extern void OS2_msg_fifo_insert (void *, void *);
extern void OS2_msg_fifo_insert_front (void *, void *);
extern void * OS2_msg_fifo_remove (void *);
extern void * OS2_msg_fifo_remove_last (void *);
extern void ** OS2_msg_fifo_remove_all (void *);
extern int OS2_msg_fifo_emptyp (void *);
extern unsigned int OS2_msg_fifo_count (void *);
extern void * OS2_msg_fifo_last (void *);

#define MSG_LENGTH(m) (OS2_message_type_length (MSG_TYPE (m)))

#define SET_MSG_TYPE_LENGTH(t, s)					\
  OS2_set_message_type_length ((t), (sizeof (s)))

#define OS2_create_message(type) OS2_create_message_1 ((type), 0)

typedef struct
{
  DECLARE_MSG_HEADER_FIELDS;
  int code;
} sm_console_interrupt_t;
#define SM_CONSOLE_INTERRUPT_CODE(m) (((sm_console_interrupt_t *) (m)) -> code)

typedef msg_t sm_timer_event_t;
typedef msg_t sm_init_t;
typedef msg_t sm_generic_reply_t;

#endif /* SCM_OS2MSG_H */