--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/utils/_os.py	Wed Jun 02 18:57:35 2010 +0200
@@ -0,0 +1,46 @@
+import os
+from os.path import join, normcase, normpath, abspath, isabs, sep
+from django.utils.encoding import force_unicode
+
+# Define our own abspath function that can handle joining 
+# unicode paths to a current working directory that has non-ASCII
+# characters in it.  This isn't necessary on Windows since the 
+# Windows version of abspath handles this correctly.  The Windows
+# abspath also handles drive letters differently than the pure 
+# Python implementation, so it's best not to replace it.
+if os.name == 'nt':
+    abspathu = abspath
+else:
+    def abspathu(path):
+        """
+        Version of os.path.abspath that uses the unicode representation
+        of the current working directory, thus avoiding a UnicodeDecodeError
+        in join when the cwd has non-ASCII characters.
+        """
+        if not isabs(path):
+            path = join(os.getcwdu(), path)
+        return normpath(path)
+
+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).
+    base = force_unicode(base)
+    paths = [force_unicode(p) for p in paths]
+    final_path = normcase(abspathu(join(base, *paths)))
+    base_path = normcase(abspathu(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