Move utility functions over to compat

This moves the py2/py3 specific code into two separate functions
in the compat module.

No other functional changes.  I also inlined the conversion of the
parsed qs dict back to unicode as nothing else currently needs that
function and doesn't need to be a public API for now.

boto/auth.py

@@ -39,7 +39,7 @@
 import os
 import posixpath
 
-from boto.compat import urllib, encodebytes
+from boto.compat import urllib, encodebytes, parse_qs_safe
 from boto.auth_handler import AuthHandler
 from boto.exception import BotoClientError
 
@@ -690,7 +690,7 @@ def mangle_path_and_params(self, req):
             modified_req.params = copy_params
 
         raw_qs = parsed_path.query
-        existing_qs = boto.utils.parse_qs_safe(
+        existing_qs = parse_qs_safe(
             raw_qs,
             keep_blank_values=True
         )

boto/compat.py

@@ -63,6 +63,7 @@
     long_type = int
     from configparser import ConfigParser, NoOptionError, NoSectionError
     unquote_str = unquote_plus
+    parse_qs_safe = parse_qs
 else:
     StandardError = StandardError
     long_type = long
@@ -78,3 +79,24 @@ def unquote_str(value, encoding='utf-8'):
         # unquote it.
         byte_string = value.encode(encoding)
         return unquote_plus(byte_string).decode(encoding)
+
+    # These are the same default arguments for python3's
+    # urllib.parse.parse_qs.
+    def parse_qs_safe(qs, keep_blank_values=False, strict_parsing=False,
+                      encoding='utf-8', errors='replace'):
+        """Parse a query handling unicode arguments properly in Python 2."""
+        is_text_type = isinstance(qs, six.text_type)
+        if is_text_type:
+            # URL encoding uses ASCII code points only.
+            qs = qs.encode('ascii')
+        qs_dict = parse_qs(qs, keep_blank_values, strict_parsing)
+        if is_text_type:
+            # Decode the parsed dictionary back to unicode.
+            result = {}
+            for (name, value) in qs_dict.items():
+                decoded_name = name.decode(encoding, errors)
+                decoded_value = [item.decode(encoding, errors)
+                                 for item in value]
+                result[decoded_name] = decoded_value
+            return result
+        return qs_dict

boto/utils.py

@@ -104,33 +104,6 @@ def unquote_v(nv):
         return (nv[0], urllib.parse.unquote(nv[1]))
 
 
-def parse_qs_safe(qs, keep_blank_values=False, strict_parsing=False,
-                  encoding='utf-8', errors='replace'):
-    """Parse a query handling unicode arguments properly in Python 2."""
-    if six.PY3:
-        return urllib.parse.parse_qs(qs, keep_blank_values, strict_parsing,
-                                     encoding, errors)
-    else:
-        is_text_type = isinstance(qs, six.text_type)
-        if is_text_type:
-            qs = qs.encode('ascii')  # URL encoding uses ASCII code points only
-
-        qs_dict = urllib.parse.parse_qs(qs, keep_blank_values, strict_parsing)
-
-        if is_text_type:
-            return decode_qs_dict(qs_dict, encoding, errors)
-        return qs_dict
-
-
-def decode_qs_dict(qs_dict, encoding='utf-8', errors='replace'):
-    result = {}
-    for (name, value) in qs_dict.items():
-        decoded_name = name.decode(encoding, errors)
-        decoded_value = [item.decode(encoding, errors) for item in value]
-        result[decoded_name] = decoded_value
-    return result
-
-
 def canonical_string(method, path, headers, expires=None,
                      provider=None):
     """