Re: [PATCHv4 1/2] submodule: port resolve_relative_url from shell to C

Stefan Beller [off-list ref] writes:

+static char *relative_url(const char *remote_url,
+				const char *url,
+				const char *up_path)
+{
+	int is_relative = 0;
+	int colonsep = 0;
+	char *out;
+	char *remoteurl = xstrdup(remote_url);
+	struct strbuf sb = STRBUF_INIT;
+	size_t len = strlen(remoteurl);
+
+	if (is_dir_sep(remoteurl[len]))
+		remoteurl[len] = '\0';
+
+	if (!url_is_local_not_ssh(remoteurl) || is_absolute_path(remoteurl))
+		is_relative = 0;
+	else {
+		is_relative = 1;
+		/*
+		 * Prepend a './' to ensure all relative
+		 * remoteurls start with './' or '../'
+		 */
+		if (!starts_with_dot_slash(remoteurl) &&
+		    !starts_with_dot_dot_slash(remoteurl)) {
+			strbuf_reset(&sb);
+			strbuf_addf(&sb, "./%s", remoteurl);
+			free(remoteurl);
+			remoteurl = strbuf_detach(&sb, NULL);
+		}
+	}
+	/*
+	 * When the url starts with '../', remove that and the
+	 * last directory in remoteurl.
+	 */
+	while (url) {
+		if (starts_with_dot_dot_slash(url)) {
+			url += 3;
+			colonsep |= chop_last_dir(&remoteurl, is_relative);
+		} else if (starts_with_dot_slash(url))
+			url += 2;
+		else
+			break;
+	}
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s%s%s", remoteurl, colonsep ? ":" : "/", url);
+
+	if (starts_with_dot_slash(sb.buf))
+		out = xstrdup(sb.buf + 2);
+	else
+		out = xstrdup(sb.buf);
+	strbuf_reset(&sb);
+
+	free(remoteurl);

This is a rather strange place to put this free(), as you are done
with it a bit earlier, but it's OK.  I briefly wondered if the code
becomes easier to follow with fewer free(remoteurl) if this local
variable is made into a strbuf, but I didn't seriously think it
through.

Otherwise looking good.

Thanks.