/* -*-C-*-

$Id: os2thrd.c,v 1.6 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.
*/

#include "os2.h"
#include "prims.h"
#include "errors.h"

#ifdef __IBMC__
#define HAVE_BEGINTHREAD
#endif

#ifdef __WATCOMC__
#include <process.h>
#define HAVE_BEGINTHREAD
#endif

#ifdef __EMX__
#define HAVE_BEGINTHREAD
#endif

extern void OS2_create_msg_queue (void);
extern ULONG APIENTRY OS2_subthread_exception_handler
  (PEXCEPTIONREPORTRECORD, PEXCEPTIONREGISTRATIONRECORD, PCONTEXTRECORD,
   PVOID);

TID
OS2_beginthread (thread_procedure_t procedure,
		 void * argument,
		 unsigned int stack_size)
{
  ULONG ss
    = ((stack_size < 0x2000)
       ? 0x2000
       : ((stack_size + 0xfff) & (~0xfff)));
#ifdef HAVE_BEGINTHREAD
  int result = (_beginthread (procedure, 0, ss, argument));
  if (result < 0)
    OS2_error_system_call (ERROR_MAX_THRDS_REACHED, syscall_beginthread);
  return (result);
#else /* not HAVE_BEGINTHREAD */
  TID tid;
  STD_API_CALL (dos_create_thread,
		((&tid), ((PFNTHREAD) procedure), ((ULONG) argument), 0, ss));
  return (tid);
#endif /* not HAVE_BEGINTHREAD */
}

void
OS2_endthread (void)
{
  DosUnsetExceptionHandler (THREAD_EXCEPTION_HANDLER ());
#ifdef HAVE_BEGINTHREAD
  _endthread ();
#else
  dos_exit (EXIT_THREAD, 0);
#endif
}

void
OS2_kill_thread (TID tid)
{
  STD_API_CALL (dos_kill_thread, (tid));
}

TID
OS2_current_tid (void)
{
  PTIB ptib;
  PPIB ppib;
  STD_API_CALL (dos_get_info_blocks, ((&ptib), (&ppib)));
  return (ptib -> tib_ptib2 -> tib2_ultid);
}

#ifndef __IBMC__
#define MAX_TID 999
static thread_store_t * thread_store_array [MAX_TID + 1];

thread_store_t **
OS2_threadstore (void)
{
  TID tid = (OS2_current_tid ());
  if (tid > MAX_TID)
    OS2_logic_error ("Unexpectedly large TID.");
  return (& (thread_store_array [tid]));
}
#endif

PID OS2_scheme_pid;
TID OS2_scheme_tid;

static void thread_initialize_1 (qid_t);
static void restore_errors (void *);
static void signal_error (msg_t *);
static void ignore_error (msg_t *);
static void send_error (msg_t *);

void
OS2_initialize_scheme_thread (void)
{
  SET_MSG_TYPE_LENGTH (mt_syscall_error, sm_syscall_error_t);
  SET_MSG_TYPE_LENGTH (mt_error, sm_error_t);
  SET_MSG_TYPE_LENGTH (mt_kill_request, sm_kill_request_t);
  {
    PTIB ptib;
    PPIB ppib;
    STD_API_CALL (dos_get_info_blocks, ((&ptib), (&ppib)));
    OS2_scheme_pid = (ppib -> pib_ulpid);
    OS2_scheme_tid = (ptib -> tib_ptib2 -> tib2_ultid);
  }
  thread_initialize_1 (QID_NONE);
  (THREAD_ERROR_HOOK ()) = signal_error;
}

int
OS2_thread_initialize (PEXCEPTIONREGISTRATIONRECORD registration,
		       qid_t error_qid)
{
  /* Every thread has a message queue, so that we can use message
     dialogs to report fatal errors to the user.  Otherwise, Scheme
     will just die with no explanation.  */
  OS2_create_msg_queue ();
  return (OS2_thread_initialize_1 (registration, error_qid));
}

int
OS2_thread_initialize_1 (PEXCEPTIONREGISTRATIONRECORD registration,
			 qid_t error_qid)
{
  thread_initialize_1 (error_qid);
  (registration -> ExceptionHandler) = OS2_subthread_exception_handler;
  DosSetExceptionHandler (registration);
  (THREAD_EXCEPTION_HANDLER ()) = registration;
  (THREAD_ERROR_HOOK ()) = send_error;
  return (setjmp (THREAD_ERROR_RESTART ()));
}

static void
thread_initialize_1 (qid_t error_qid)
{
  (* (OS2_threadstore ())) = (OS_malloc (sizeof (thread_store_t)));
  (THREAD_ERROR_QUEUE ()) = error_qid;
  ((THREAD_FATAL_ERROR_BUFFER ()) [0]) = '\0';
}

char *
OS2_thread_fatal_error_buffer (void)
{
  /* The default buffer may get used if an error occurs very early in
     a thread, before the regular error buffer is allocated.  This can
     easily happen in the Scheme thread, but shouldn't happen in the
     other threads.  */
  static char default_buffer [1024] = "";
  return
    (((* (OS2_threadstore ())) == 0)
     ? default_buffer
     : (THREAD_FATAL_ERROR_BUFFER ()));
}

int
OS2_error_message_p (msg_t * message)
{
  msg_type_t type = (MSG_TYPE (message));
  return ((type == mt_syscall_error) || (type == mt_error));
}

void
OS2_handle_error_message (msg_t * message)
{
  (* (THREAD_ERROR_HOOK ())) (message);
}

void
OS2_ignore_errors (void)
{
  error_hook_t * hp = (dstack_alloc (sizeof (error_hook_t)));
  (*hp) = (THREAD_ERROR_HOOK ());
  transaction_record_action (tat_always, restore_errors, hp);
  (THREAD_ERROR_HOOK ()) = ignore_error;
}

static void
restore_errors (void * hp)
{
  (THREAD_ERROR_HOOK ()) = (* ((error_hook_t *) hp));
}

void
OS2_error_system_call (int code, enum syscall_names name)
{
  OS2_handle_error_message (OS2_make_syscall_error (code, name));
}

void
OS2_error_anonymous (void)
{
  OS2_handle_error_message (OS2_make_error (ERR_EXTERNAL_RETURN));
}

void
OS2_error_unimplemented_primitive (void)
{
  OS2_handle_error_message (OS2_make_error (ERR_UNDEFINED_PRIMITIVE));
}

void
OS2_error_out_of_channels (void)
{
  OS2_handle_error_message (OS2_make_error (ERR_OUT_OF_FILE_HANDLES));
}

static void
signal_error (msg_t * message)
{
  switch (MSG_TYPE (message))
    {
    case mt_syscall_error:
      {
	int code = (SM_SYSCALL_ERROR_CODE (message));
	enum syscall_names name = (SM_SYSCALL_ERROR_NAME (message));
	OS2_destroy_message (message);
	error_system_call (code, name);
      }
      break;
    case mt_error:
      {
	long code = (SM_ERROR_CODE (message));
	OS2_destroy_message (message);
	signal_error_from_primitive (code);
      }
      break;
    default:
      OS2_logic_error ("Non-error message passed to signal_error.");
      break;
    }
}

static void
ignore_error (msg_t * message)
{
}

static void
send_error (msg_t * message)
{
  if ((THREAD_ERROR_QUEUE ()) == QID_NONE)
    OS2_logic_error ("send_error called when no error queue defined.");
  OS2_send_message ((THREAD_ERROR_QUEUE ()), message);
  longjmp ((THREAD_ERROR_RESTART ()), 1);
}

msg_t *
OS2_make_syscall_error (int code, enum syscall_names name)
{
  msg_t * message = (OS2_create_message (mt_syscall_error));
  (SM_SYSCALL_ERROR_CODE (message)) = code;
  (SM_SYSCALL_ERROR_NAME (message)) = name;
  return (message);
}

msg_t *
OS2_make_error (long code)
{
  msg_t * message = (OS2_create_message (mt_error));
  (SM_ERROR_CODE (message)) = code;
  return (message);
}