--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/utils/_os.py Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,23 @@
+from os.path import join, normcase, abspath, sep
+
+def safe_join(base, *paths):
+ """
+ Joins one or more path components to the base path component intelligently.
+ Returns a normalized, absolute version of the final path.
+
+ The final path must be located inside of the base path component (otherwise
+ a ValueError is raised).
+ """
+ # We need to use normcase to ensure we don't false-negative on case
+ # insensitive operating systems (like Windows).
+ final_path = normcase(abspath(join(base, *paths)))
+ base_path = normcase(abspath(base))
+ base_path_len = len(base_path)
+ # Ensure final_path starts with base_path and that the next character after
+ # the final path is os.sep (or nothing, in which case final_path must be
+ # equal to base_path).
+ if not final_path.startswith(base_path) \
+ or final_path[base_path_len:base_path_len+1] not in ('', sep):
+ raise ValueError('the joined path is located outside of the base path'
+ ' component')
+ return final_path