Canonicalize paths before using them further

Convert/normalize path types before further usage
and attempt to translate non-string objects so that
they can be used correctly in further interprocess
locking code.

Fixes issue #16

fasteners/_utils.py

@@ -17,8 +17,25 @@
 #    under the License.
 
 import logging
+import sys
 import time
 
+try:
+    from os import fsencode as _fsencode
+except (ImportError, AttributeError):
+    def _fsencode(path):
+        # Replicate similar logic to what py3.2+ fsencode does.
+        # See: https://bugs.python.org/issue8514
+        encoding = sys.getfilesystemencoding()
+        if encoding == 'mbcs':
+            errors = 'strict'
+        else:
+            errors = 'surrogateescape'
+        return path.encode(encoding, errors)
+
+
+import six
+
 from monotonic import monotonic as now  # noqa
 
 # log level for low-level debugging
@@ -27,6 +44,19 @@ BLATHER = 5
 LOG = logging.getLogger(__name__)
 
 
+def canonicalize_path(path):
+    """Canonicalizes a potential path.
+
+    Returns a binary string encoded into filesystem encoding.
+    """
+    if isinstance(path, six.binary_type):
+        return path
+    if isinstance(path, six.text_type):
+        return _fsencode(path)
+    else:
+        return canonicalize_path(str(path))
+
+
 def pick_first_not_none(*values):
     """Returns first of values that is *not* None (or None if all are/were)."""
     for val in values:

fasteners/process_lock.py

@@ -84,7 +84,7 @@ class _InterProcessLock(object):
 
     def __init__(self, path, sleep_func=time.sleep, logger=None):
         self.lockfile = None
-        self.path = path
+        self.path = _utils.canonicalize_path(path)
         self.acquired = False
         self.sleep_func = sleep_func
         self.logger = _utils.pick_first_not_none(logger, LOG)