[PATCH 3/5] Add is_root_path()

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

This function returns the length of the root part of a path, or zero if
there is no root.

"The root part" is the leading slash on Linux/Unix, or 'C:/' on Windows.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 ... and can be extended to recognize "//machine/share/" as a root part?

 git-compat-util.h |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/git-compat-util.h b/git-compat-util.h
index a3c4537..4d0398d 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -210,6 +210,17 @@ static inline const char *skip_prefix(const char *str, const char *prefix)
 	return strncmp(str, prefix, len) ? NULL : str + len;
 }
 
+/* path must be canonical */
+static inline int is_root_path(const char *path)
+{
+	int len = 0;
+	if (has_dos_drive_prefix(path))
+		len += 2;
+	if (is_dir_sep(path[len]))
+		len++;
+	return len;
+}
+
 #if defined(NO_MMAP) || defined(USE_WIN32_MMAP)
 
 #ifndef PROT_READ
-- 
1.7.0.rc2.182.g3adef