/*
 *	PROGRAM:	JRD Lock Manager
 *	MODULE:		vmslock.c
 *	DESCRIPTION:	VMS Lock Manager
 *
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at http://www.Inprise.com/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Inprise Corporation
 * and its predecessors. Portions created by Inprise Corporation are
 * Copyright (C) Inprise Corporation.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 */

#include "firebird.h"
#include descrip
#include psldef
#include ssdef
#include lckdef

#include "../jrd/common.h"
#include "../jrd/gds.h"
#include "../jrd/isc_proto.h"
#include "../jrd/sch_proto.h"
#include "../jrd/vmslo_proto.h"

#define	PTR		int
#define EVENT_FLAG	15

static SCHAR lock_types[] = {
	0,
	LCK$K_NLMODE,
	LCK$K_CRMODE,
	LCK$K_CWMODE,
	LCK$K_PRMODE,
	LCK$K_PWMODE,
	LCK$K_EXMODE
};

typedef struct lksb {
	SSHORT lksb_status;
	SSHORT lksb_reserved;
	SLONG lksb_lock_id;
	SLONG lksb_value[4];
} LKSB;

static int lock_error(STATUS *, UCHAR *, int);
static SLONG write_data(SLONG, SLONG);


int LOCK_convert(
				 PTR lock_id,
				 UCHAR type,
				 SSHORT wait,
				 int (*ast_routine) (int *),
int *ast_argument, STATUS * status_vector)
{
/**************************************
 *
 *	L O C K _ c o n v e r t
 *
 **************************************
 *
 * Functional description
 *	Perform a lock conversion, if possible.  If the lock cannot be
 *	granted immediately, either return immediately or wait depending
 *	on a wait flag.  If the lock is granted return TRUE, otherwise
 *	return FALSE.  Note: if the conversion would cause a deadlock,
 *	FALSE is returned even if wait was requested.
 *
 **************************************/
	int status;
	LKSB lksb;
	struct dsc$descriptor_s desc;

	lksb.lksb_lock_id = lock_id;

	status = sys$enq(EVENT_FLAG,
					 lock_types[type],
					 &lksb,
					 (wait) ? LCK$M_CONVERT : LCK$M_CONVERT | LCK$M_NOQUEUE,
					 &desc, NULL,	/* Lock parent (not used) */
					 gds__completion_ast,	/* AST routine when granted */
					 ast_argument, ast_routine, NULL, NULL);

	if (status & 1)
		ISC_wait(&lksb, EVENT_FLAG);

	if ((status & 1) && ((status = lksb.lksb_status) & 1))
		return TRUE;

	if (!wait && status == SS$_NOTQUEUED)
		status = SS$_DEADLOCK;

	return lock_error(status_vector, "sys$enq", status);
}


int LOCK_deq(PTR lock_id)
{
/**************************************
 *
 *	L O C K _ d e q 
 *
 **************************************
 *
 * Functional description
 *	Release an outstanding lock.
 *
 **************************************/
	int status;

	status = sys$deq(lock_id, NULL, NULL, NULL);

/* The following is a deliberate compile error to force this to
   be fixed during the next VMS port.  Return FALSE if any error
   TRUE if everything OK. */
	return the_appropriate_value;
}


SLONG LOCK_enq(PTR prior_request;
			   PTR parent_request;
			   USHORT series;
			   UCHAR * value;
			   USHORT length;
			   UCHAR type;
			   int (*ast_routine) (int *);
			   int *ast_argument; SLONG data; USHORT wait;
			   STATUS * status_vector; {
/**************************************
 *
 *	L O C K _ e n q
 *
 **************************************
 *
 * Functional description
 *	Enque on a lock.  If the lock can't be granted immediately,
 *	return an event count on which to wait.  If the lock can't
 *	be granted because of deadlock, return NULL.
 *
 **************************************/
			   int status, lock_id, lock_type, flags;
			   UCHAR buffer[256], *p;
			   LKSB lksb;
			   struct dsc$descriptor_s desc;
			   if (prior_reqeust)
			   LOCK_deq(prior_request); p = buffer; *p++ = series; if (length)
			   do
			   *p++ = *value++; while (--length);
			   desc.dsc$b_class = DSC$K_CLASS_S;
			   desc.dsc$b_dtype = DSC$K_DTYPE_T;
			   desc.dsc$w_length = p - buffer;
			   desc.dsc$a_pointer = buffer;
			   flags =
			   (wait) ? LCK$M_SYSTEM | LCK$M_VALBLK : LCK$M_SYSTEM |
			   LCK$M_NOQUEUE; lock_type = lock_types[type];
			   status =
			   sys$enq(EVENT_FLAG, lock_type, &lksb, flags, &desc, parent_request, gds__completion_ast,	/* AST routine when granted */
					   ast_argument, ast_routine, PSL$C_USER, NULL);
			   if (status & 1) ISC_wait(&lksb, EVENT_FLAG); if ((status & 1)
																&&
																(((status
																   =
																   lksb.
																   lksb_status)
																  & 1)
																 || status ==
																 SS$_VALNOTVALID))
			   {
			   if (data) {
			   if (lock_type == LCK$K_EXMODE)
			   write_data(lksb.lksb_lock_id, data);
			   else
			   LOCK_write_data(lksb.lksb_lock_id, data);}
			   return lksb.lksb_lock_id;}

			   if (!wait && status == SS$_NOTQUEUED)
			   status = SS$_DEADLOCK;
			   return lock_error(status_vector, "sys$enq", status);}


			   void LOCK_fini(STATUS * status_vector, PTR * owner_offset) {
/**************************************
 *
 *	L O C K _ f i n i
 *
 **************************************
 *
 * Functional description
 *	Release the process block, any outstanding locks,
 *	and unmap the lock manager.  This is usually called
 *	by the cleanup handler.
 *
 **************************************/

			   return FB_SUCCESS;}


			   int LOCK_init(STATUS * status_vector,
							 SSHORT owner_flag,
							 SLONG owner_id,
							 UCHAR owner_type, SLONG * owner_handle) {
/**************************************
 *
 *	L O C K _ i n i t
 *
 **************************************
 *
 * Functional description
 *	Initialize lock manager for process.
 *
 **************************************/

			   return FB_SUCCESS;}


			   SLONG LOCK_read_data(PTR lock_id) {
/**************************************
 *
 *	L O C K _ r e a d _ d a t a
 *
 **************************************
 *
 * Functional description
 *	Read data associated with a lock.
 *
 **************************************/
			   int status;
			   LKSB lksb;
			   struct dsc$descriptor_s desc;
			   lksb.lksb_lock_id = lock_id;
			   lksb.lksb_value[0] = 0;
			   status = sys$enq(EVENT_FLAG,
								LCK$K_NLMODE, &lksb,
								LCK$M_CONVERT | LCK$M_VALBLK, &desc, NULL,	/* Lock parent (not used) */
								gds__completion_ast,	/* AST routine when granted */
								NULL, NULL, NULL, NULL); if (status & 1)
			   ISC_wait(&lksb, EVENT_FLAG);
			   if (!status && !(lksb.lksb_status & 1))
			   return 0; return lksb.lksb_value[0];}


			   void LOCK_re_post(int (*ast_routine) (int *),
								 int ast_argument, PTR owner_offset) {
/**************************************
 *
 *	L O C K _ r e _ p o s t
 *
 **************************************
 *
 * Functional description
 *	Re-post an AST.
 *
 **************************************/
			   int status;
			   status = sys$dclast(ast_routine, ast_argument, PSL$C_USER);}


			   SLONG LOCK_write_data(PTR lock_id, SLONG data) {
/**************************************
 *
 *	L O C K _ w r i t e _ d a t a
 *
 **************************************
 *
 * Functional description
 *	Perform a conversion to exclusive in preparation
 *	for a downward conversion to write data to lock.
 *
 **************************************/
			   int status;
			   LKSB lksb;
			   struct dsc$descriptor_s desc;
			   lksb.lksb_lock_id = lock_id;
			   status =
			   sys$enq(EVENT_FLAG, LCK$K_EXMODE, &lksb, LCK$M_CONVERT, &desc, NULL,	/* Lock parent (not used) */
					   gds__completion_ast,	/* AST routine when granted */
					   NULL, NULL, NULL, NULL); if (status & 1)
			   ISC_wait(&lksb, EVENT_FLAG);
			   if (!(status & 1) || !((status = lksb.lksb_status) & 1))
			   return 0; return write_data(lock_id, data);}


			   static int lock_error(STATUS * status_vector,
									 UCHAR * string, int code) {
/**************************************
 *
 *	l o c k _ e r r o r
 *
 **************************************
 *
 * Functional description
 *	Report lock manager error.
 *
 **************************************/

			   if (code == SS$_DEADLOCK) {
			   *status_vector++ = gds_arg_gds;
			   *status_vector++ = gds__deadlock;}

			   *status_vector++ = gds_arg_gds;
			   *status_vector++ = gds__sys_request;
			   *status_vector++ = gds_arg_string;
			   *status_vector++ = string;
			   *status_vector++ = gds_arg_vms;
			   *status_vector++ = code; *status_vector++ = 0; return 0;}


			   static SLONG write_data(SLONG lock_id, SLONG data) {
/**************************************
 *
 *	w r i t e _ d a t a
 *
 **************************************
 *
 * Functional description
 *	Write a longword into the lock block.
 *
 **************************************/
			   int status;
			   LKSB lksb;
			   struct dsc$descriptor_s desc;
			   lksb.lksb_lock_id = lock_id;
			   lksb.lksb_value[0] = data;
			   lksb.lksb_value[1] = 0;
			   lksb.lksb_value[2] = 0;
			   lksb.lksb_value[3] = 0;
			   status = sys$enqw(EVENT_FLAG,
								 LCK$K_PWMODE, &lksb,
								 LCK$M_CONVERT | LCK$M_VALBLK, &desc, NULL,	/* Lock parent (not used) */
								 gds__completion_ast,	/* AST routine when granted */
								 NULL,
								 NULL,
								 NULL,
								 NULL);
			   if (!(status & 1) || !((status = lksb.lksb_status) & 1))
			   return 0;}