py3: add docx.opc.compat module

Steve Canny · Steve Canny · commit 70ce190657bb · 2014-01-07T02:49:53.000-08:00
* extract is_string()
diff --git a/docx/opc/compat.py b/docx/opc/compat.py
@@ -0,0 +1,35 @@
+# encoding: utf-8
+
+"""
+Provides Python 2/3 compatibility objects
+"""
+
+from __future__ import (
+    absolute_import, division, print_function, unicode_literals
+)
+
+import sys
+
+# ===========================================================================
+# Python 3 versions
+# ===========================================================================
+
+if sys.version_info >= (3, 0):
+
+    def is_string(obj):
+        """
+        Return True if *obj* is a string, False otherwise.
+        """
+        return isinstance(obj, str)
+
+# ===========================================================================
+# Python 2 versions
+# ===========================================================================
+
+else:
+
+    def is_string(obj):
+        """
+        Return True if *obj* is a string, False otherwise.
+        """
+        return isinstance(obj, basestring)
diff --git a/docx/opc/phys_pkg.py b/docx/opc/phys_pkg.py
@@ -10,6 +10,7 @@
 
 from zipfile import ZipFile, is_zipfile, ZIP_DEFLATED
 
+from .compat import is_string
 from .exceptions import PackageNotFoundError
 from .packuri import CONTENT_TYPES_URI
 
@@ -20,7 +21,7 @@ class PhysPkgReader(object):
     """
     def __new__(cls, pkg_file):
         # if *pkg_file* is a string, treat it as a path
-        if isinstance(pkg_file, basestring):
+        if is_string(pkg_file):
             if os.path.isdir(pkg_file):
                 reader_cls = _DirPkgReader
             elif is_zipfile(pkg_file):
