/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"
#include "exec_cmd.h"

static void flush_buffer(const char *buf, unsigned long size)
{
	while (size > 0) {
		long ret = xwrite(1, buf, size);
		if (ret < 0) {
			/* Ignore epipe */
			if (errno == EPIPE)
				break;
			die("git-cat-file: %s", strerror(errno));
		} else if (!ret) {
			die("git-cat-file: disk full?");
		}
		size -= ret;
		buf += ret;
	}
}

static int pprint_tag(const unsigned char *sha1, const char *buf, unsigned long size)
{
	/* the parser in tag.c is useless here. */
	const char *endp = buf + size;
	const char *cp = buf;

	while (cp < endp) {
		char c = *cp++;
		if (c != '\n')
			continue;
		if (7 <= endp - cp && !memcmp("tagger ", cp, 7)) {
			const char *tagger = cp;

			/* Found the tagger line.  Copy out the contents
			 * of the buffer so far.
			 */
			flush_buffer(buf, cp - buf);

			/*
			 * Do something intelligent, like pretty-printing
			 * the date.
			 */
			while (cp < endp) {
				if (*cp++ == '\n') {
					/* tagger to cp is a line
					 * that has ident and time.
					 */
					const char *sp = tagger;
					char *ep;
					unsigned long date;
					long tz;
					while (sp < cp && *sp != '>')
						sp++;
					if (sp == cp) {
						/* give up */
						flush_buffer(tagger,
							     cp - tagger);
						break;
					}
					while (sp < cp &&
					       !('0' <= *sp && *sp <= '9'))
						sp++;
					flush_buffer(tagger, sp - tagger);
					date = strtoul(sp, &ep, 10);
					tz = strtol(ep, NULL, 10);
					sp = show_date(date, tz);
					flush_buffer(sp, strlen(sp));
					xwrite(1, "\n", 1);
					break;
				}
			}
			break;
		}
		if (cp < endp && *cp == '\n')
			/* end of header */
			break;
	}
	/* At this point, we have copied out the header up to the end of
	 * the tagger line and cp points at one past \n.  It could be the
	 * next header line after the tagger line, or it could be another
	 * \n that marks the end of the headers.  We need to copy out the
	 * remainder as is.
	 */
	if (cp < endp)
		flush_buffer(cp, endp - cp);
	return 0;
}

int main(int argc, char **argv)
{
	unsigned char sha1[20];
	char type[20];
	void *buf;
	unsigned long size;
	int opt;

	setup_git_directory();
	git_config(git_default_config);
	if (argc != 3 || get_sha1(argv[2], sha1))
		usage("git-cat-file [-t|-s|-e|-p|<type>] <sha1>");

	opt = 0;
	if ( argv[1][0] == '-' ) {
		opt = argv[1][1];
		if ( !opt || argv[1][2] )
			opt = -1; /* Not a single character option */
	}

	buf = NULL;
	switch (opt) {
	case 't':
		if (!sha1_object_info(sha1, type, NULL)) {
			printf("%s\n", type);
			return 0;
		}
		break;

	case 's':
		if (!sha1_object_info(sha1, type, &size)) {
			printf("%lu\n", size);
			return 0;
		}
		break;

	case 'e':
		return !has_sha1_file(sha1);

	case 'p':
		if (get_sha1(argv[2], sha1) ||
		    sha1_object_info(sha1, type, NULL))
			die("Not a valid object name %s", argv[2]);

		/* custom pretty-print here */
		if (!strcmp(type, "tree"))
			return execl_git_cmd("ls-tree", argv[2], NULL);

		buf = read_sha1_file(sha1, type, &size);
		if (!buf)
			die("Cannot read object %s", argv[2]);
		if (!strcmp(type, "tag"))
			return pprint_tag(sha1, buf, size);

		/* otherwise just spit out the data */
		break;
	case 0:
		buf = read_object_with_reference(sha1, argv[1], &size, NULL);
		break;

	default:
		die("git-cat-file: unknown option: %s\n", argv[1]);
	}

	if (!buf)
		die("git-cat-file %s: bad file", argv[2]);

	flush_buffer(buf, size);
	return 0;
}