import unicodedata
import sys


# HFS Plus uses decomposed UTF-8
def decompose(path):
 if isinstance(path, str):
 return unicodedata.normalize('NFD', path)
 try:
 path = path.decode('utf-8')
 path = unicodedata.normalize('NFD', path)
 path = path.encode('utf-8')
 except UnicodeError:
 pass # Not UTF-8
 return path


def filesys_decode(path):
 """
 Ensure that the given path is decoded,
 NONE when no expected encoding works
 """

 if isinstance(path, str):
 return path

 fs_enc = sys.getfilesystemencoding() or 'utf-8'
 candidates = fs_enc, 'utf-8'

 for enc in candidates:
 try:
 return path.decode(enc)
 except UnicodeDecodeError:
 continue


def try_encode(string, enc):
 "turn unicode encoding into a functional routine"
 try:
 return string.encode(enc)
 except UnicodeEncodeError:
 return None