/* Copyright (c) 1997 Silicon Graphics, Inc. */

#ifndef lint
static char SCCSid[] = "$SunId$ SGI";
#endif

/*
 * Holodeck display process communication
 */

#include "rholo.h"
#include "rhdisp.h"
#include <sys/uio.h>

#ifndef HDSUF
#define HDSUF	".hdisp"
#endif

static int	inp_flags;
static int	dpd[3];
static int	pipesiz;


disp_open(dname)		/* open the named display driver */
char	*dname;
{
	char	dpath[128], *com[2];
	int	i;

#ifdef DEVPATH
	sprintf(dpath, "%s/%s%s", DEVPATH, dname, HDSUF);
#else
	sprintf(dpath, "dev/%s%s", dname, HDSUF);
#endif
	com[0] = dpath; com[1] = NULL;
	pipesiz = open_process(dpd, com);
	if (pipesiz <= 0)
		error(USER, "cannot start display process");
	inp_flags = 0;
				/* write out hologram grids */
	for (i = 0; hdlist[i] != NULL; i++)
		disp_result(DS_ADDHOLO, sizeof(HDGRID), (char *)hdlist[i]);
}


disp_packet(p)			/* display a packet */
register PACKET	*p;
{
	if (pipesiz <= 0)
		return;
	disp_result(DS_BUNDLE, sizeof(PACKHEAD) + p->nr*sizeof(RAYVAL),
			(char *)p);
}


disp_check(block)		/* check display process */
int	block;
{
	MSGHEAD	msg;
	int	n;
	char	*buf = NULL;

	if (pipesiz <= 0)
		return(-1);
restart:				/* check read blocking */
	if (block != (inp_flags == 0)) {
		inp_flags = block ? 0 : FNONBLK;
		if (fcntl(dpd[0], F_SETFL, inp_flags) < 0)
			goto fcntlerr;
	}
					/* read message header */
	n = read(dpd[0], (char *)&msg, sizeof(MSGHEAD));
	if (n != sizeof(MSGHEAD)) {
		if (n >= 0)
			error(USER, "display process died");
		if (errno != EAGAIN & errno != EINTR)
			goto readerr;
		return(2);		/* else acceptable failure */
	}
	if (msg.nbytes) {		/* get the message body */
		buf = (char *)malloc(msg.nbytes);
		if (buf == NULL)
			error(SYSTEM, "out of memory in disp_check");
		if (fcntl(dpd[0], F_SETFL, inp_flags=0) < 0)
			goto fcntlerr;
		if (readbuf(dpd[0], buf, msg.nbytes) != msg.nbytes)
			goto readerr;
	}
	switch (msg.type) {		/* take appropriate action */
	case DR_BUNDLE:
		if (msg.nbytes != sizeof(PACKHEAD))
			error(INTERNAL, "bad DR_BUNDLE from display process");
		bundle_set(BS_ADD, (PACKHEAD *)buf, 1);
		break;
	case DR_NEWSET:
		if (msg.nbytes % sizeof(PACKHEAD))
			error(INTERNAL, "bad DR_NEWSET from display process");
		disp_result(DS_STARTIMM, 0, NULL);
		bundle_set(BS_NEW, (PACKHEAD *)buf, msg.nbytes/sizeof(PACKHEAD));
		disp_result(DS_ENDIMM, 0, NULL);
		break;
	case DR_ADDSET:
		if (msg.nbytes % sizeof(PACKHEAD))
			error(INTERNAL, "bad DR_ADDSET from display process");
		disp_result(DS_STARTIMM, 0, NULL);
		bundle_set(BS_ADD, (PACKHEAD *)buf, msg.nbytes/sizeof(PACKHEAD));
		disp_result(DS_ENDIMM, 0, NULL);
		break;
	case DR_DELSET:
		if (msg.nbytes % sizeof(PACKHEAD))
			error(INTERNAL, "bad DR_DELSET from display process");
		bundle_set(BS_DEL, (PACKHEAD *)buf, msg.nbytes/sizeof(PACKHEAD));
		break;
	case DR_ATTEN:
		if (msg.nbytes)
			error(INTERNAL, "bad DR_ATTEN from display process");
					/* send acknowledgement */
		disp_result(DS_ACKNOW, 0, NULL);
		block = 1;		/* block on following request */
		goto restart;
	case DR_SHUTDOWN:
		if (msg.nbytes)
			error(INTERNAL, "bad DR_SHUTDOWN from display process");
		return(0);		/* zero return signals shutdown */
	default:
		error(INTERNAL, "unrecognized request from display process");
	}
	if (msg.nbytes)
		free(buf);
	return(1);			/* normal return value */
fcntlerr:
	error(SYSTEM, "cannot change display blocking mode");
readerr:
	error(SYSTEM, "error reading from display process");
}


int
disp_close()			/* close our display process */
{
	int	rval;

	if (pipesiz <= 0)
		return(-1);
	disp_result(DS_SHUTDOWN, 0, NULL);
	pipesiz = 0;
	return(close_process(dpd));
}


disp_result(type, nbytes, p)	/* send result message to display process */
int	type, nbytes;
char	*p;
{
	struct iovec	iov[2];
	MSGHEAD	msg;
	int	n;

	msg.type = type;
	msg.nbytes = nbytes;
	if (nbytes == 0 || sizeof(MSGHEAD)+nbytes > pipesiz) {
		n = write(dpd[1], (char *)&msg, sizeof(MSGHEAD));
		if (n != sizeof(MSGHEAD))
			goto writerr;
		if (nbytes > 0) {
			n = writebuf(dpd[1], p, nbytes);
			if (n != nbytes)
				goto writerr;
		}
		return;
	}
	iov[0].iov_base = (char *)&msg;
	iov[0].iov_len = sizeof(MSGHEAD);
	iov[1].iov_base = p;
	iov[1].iov_len = nbytes;
	n = writev(dpd[1], iov, 2);
	if (n == nbytes+sizeof(MSGHEAD))
		return;
writerr:
	error(SYSTEM, "write error in disp_result");
}