[PATCHv2] Porting resolve_relative_url from shell to C

[Stefan Beller <sbeller@google.com>]

A new version of the patch, which spells out more its intent and
may actually work in Windows.

Any comment welcome,
Thanks,
Stefan

Stefan Beller (1):
  submodule: Port resolve_relative_url from shell to C

 builtin/submodule--helper.c | 151 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  81 ++----------------------
 2 files changed, 155 insertions(+), 77 deletions(-)

interdiff to previous version:

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index f48b5b5..b925bed 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -31,6 +31,36 @@ static const char *get_default_remote(void)
 		return xstrdup(dest);
 }
 
+static int has_same_dir_prefix(const char *str, const char **out)
+{
+#ifdef GIT_WINDOWS_NATIVE
+	return skip_prefix(str, "./", out)
+		|| skip_prefix(str, ".\\", out);
+#else
+	return skip_prefix(str, "./", out);
+#endif
+}
+
+static int has_upper_dir_prefix(const char *str, const char **out)
+{
+#ifdef GIT_WINDOWS_NATIVE
+	return skip_prefix(str, "../", out)
+		|| skip_prefix(str, "..\\", out);
+#else
+	return skip_prefix(str, "../", out);
+#endif
+}
+
+static char *last_dir_separator(const char *str)
+{
+#ifdef GIT_WINDOWS_NATIVE
+	return strrchr(str, "/")
+		|| strrchr(str, "\\");
+#else
+	return strrchr(str, '/');
+#endif
+}
+
 /*
  * The function takes at most 2 arguments. The first argument is the
  * URL that navigates to the submodule origin repo. When relative, this URL
@@ -64,13 +94,14 @@ static const char *relative_url(const char *url, const char *up_path)
 		/* the repository is its own authoritative upstream */
 		remoteurl = xgetcwd();
 
-	if (strip_suffix(remoteurl, "/", &len))
+	len = strlen(remoteurl);
+	if (is_dir_sep(remoteurl[len]))
 		remoteurl[len] = '\0';
 
-	if (strchr(remoteurl, ':') || skip_prefix(remoteurl, "/", &out))
+	if (strchr(remoteurl, ':') || is_dir_sep(*remoteurl))
 		is_relative = 0;
-	else if (skip_prefix(remoteurl, "./", &out) ||
-		    skip_prefix(remoteurl, "../", &out))
+	else if (has_same_dir_prefix(remoteurl, &out) ||
+		    has_upper_dir_prefix(remoteurl, &out))
 		is_relative = 1;
 	else {
 		is_relative = 1;
@@ -80,11 +111,11 @@ static const char *relative_url(const char *url, const char *up_path)
 	}
 
 	while (url) {
-		if (skip_prefix(url, "../", &out)) {
+		if (has_upper_dir_prefix(url, &out)) {
 			char *rfind;
 			url = out;
 
-			rfind = strrchr(remoteurl, '/');
+			rfind = last_dir_separator(remoteurl);
 			if (rfind)
 				*rfind = '\0';
 			else {
@@ -99,7 +130,7 @@ static const char *relative_url(const char *url, const char *up_path)
 						remoteurl = ".";
 				}
 			}
-		} else if (skip_prefix(url, "./", &out))
+		} else if (has_same_dir_prefix(url, &out))
 			url = out;
 		else
 			break;
@@ -107,7 +138,7 @@ static const char *relative_url(const char *url, const char *up_path)
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s%s%s", remoteurl, sep, url);
 
-	if (!skip_prefix(sb.buf, "./", &out))
+	if (!has_same_dir_prefix(sb.buf, &out))
 		out = sb.buf;
 	out = xstrdup(out);
 

-- 
2.7.0.rc1.2.gfc39790.dirty