/*-
 * Copyright (c) 2015, 2016 Taylor R. Campbell
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <pb.h>
#include <pb_decode.h>
#include <pb_dump.h>
#include <pb_encode.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>

#define	setprogname(argv0)	((void)0)
#define	getprogname()		"dumpdesc"

#include "descriptor.pb.h"

#ifdef __GNUC__
#define	GNUC_PREREQ(maj, min)						      \
	((__GNUC__ > (maj)) ||						      \
	 ((__GNUC__ == (maj)) && (__GNUC_MINOR__ >= (min))))
#else
#define	GNUC_PREREQ(maj, min)	0
#endif

#if GNUC_PREREQ(2,5)
#define	attr_noreturn	__attribute__((__noreturn__))
#else
#define	attr_noreturn
#endif

static pb_decoder_callback_t decode_file_callback;

static int
decode_file_callback(void *cookie, void *buf, size_t *np)
{
	FILE *file = cookie;
	size_t nreq, nread;

	nreq = *np;
	if (buf == NULL) {
		uint8_t scratch[BUFSIZ];
		size_t nremain = nreq;

		while (nremain) {
			size_t nchunk = nremain;

			if (nchunk > sizeof scratch)
				nchunk = sizeof scratch;
			assert(0 < nchunk);
			nread = fread(scratch, 1, nchunk, file);
			assert(nread <= nchunk);
			assert(nchunk <= nremain);
			nremain -= nread;
			if (nread < nchunk)
				break;
		}
		nread = nreq - nremain;
	} else {
		nread = fread(buf, 1, nreq, file);
	}
	if (nread < nreq && ferror(file))
		return errno;
	*np = nread;

	return 0;
}

static void attr_noreturn
usage(void)
{

	(void)fprintf(stderr, "Usage: %s [-bt]\n", getprogname());
	exit(1);
}

int
main(int argc, char **argv)
{
	struct FileDescriptorSet descs;
	int bflag, tflag;
	int ch;
	int error;

	setprogname(argv[0]);
	if (signal(SIGPIPE, SIG_IGN))
		err(1, "signal(SIGPIPE, SIG_IGN)");

	bflag = 0;
	tflag = 0;
	while ((ch = getopt(argc, argv, "bt")) != -1) {
		switch (ch) {
		case 'b':
			if (tflag) {
				warnx("-b and -t are incompatible");
				usage();
			}
			bflag = 1;
			break;
		case 't':
			if (bflag) {
				warnx("-b and -t are incompatible");
				usage();
			}
			tflag = 1;
			break;
		case '?':
		default:
			usage();
		}
	}
	argc -= optind;
	argv += optind;
	if (argc)
		usage();

	if (!(bflag | tflag)) {
		warnx("one of -b or -t must be specified");
		usage();
	}

	pb_init(FileDescriptorSet(&descs));
	error = pb_decode(FileDescriptorSet(&descs), &decode_file_callback,
	    stdin);
	if (error) {
		errno = error;
		err(1, "decode");
	}

	if (bflag) {
		void *buf;
		size_t n;

		error = pb_encoding_size(FileDescriptorSet(&descs), &n);
		if (error) {
			errno = error;
			err(1, "size");
		}

		buf = malloc(n ? n : 1);
		if (buf == NULL)
			err(1, "malloc");

		error = pb_encode_to_memory(FileDescriptorSet(&descs), buf, n);
		if (error) {
			errno = error;
			err(1, "encode");
		}
		if (n && fwrite(buf, n, 1, stdout) < 1)
			err(1, "fwrite");
	} else if (tflag) {
		error = pb_dump(stdout, FileDescriptorSet(&descs));
		if (error) {
			errno = error;
			err(1, "dump");
		}
	} else {
		assert(!"either bflag or tflag must have been specified");
	}

	pb_destroy(FileDescriptorSet(&descs));

	return 0;
}