Merge; Fix according to review

--HG--
branch : open_mode

1 files changed, 39 insertions, 41 deletions

diff --git a/checkers/stdlib.py b/checkers/stdlib.py
index 3caaac82b..54f8c1aee 100644
--- a/checkers/stdlib.py
+++ b/checkers/stdlib.py
@@ -32,6 +32,44 @@ if sys.version_info >= (3, 0):
 else:
     OPEN_MODULE = '__builtin__'
 
+
+def _check_mode_str(mode):
+    # check type
+    if not isinstance(mode, six.string_types):
+        return False
+    # check syntax
+    modes = set(mode)
+    _mode = "rwatb+U"
+    if six.PY3:
+        _mode += "x"
+        creating = "x" in modes
+    if modes - set(_mode) or len(mode) > len(modes):
+        return False
+    # check logic
+    creating = False
+    reading = "r" in modes
+    writing = "w" in modes
+    appending = "a" in modes
+    updating = "+" in modes
+    text = "t" in modes
+    binary = "b" in modes
+    if "U" in modes:
+        if writing or appending or creating and six.PY3:
+            return False
+        reading = True
+    if text and binary:
+        return False
+    total = reading + writing + appending + (creating if six.PY3 else 0)
+    if total > 1:
+        return False
+    if not (reading or writing or appending or creating and six.PY3):
+        return False
+    # 2.x constraints
+    if not six.PY3:
+        return mode[0] in ("r", "w", "a", "U")
+    return True
+
+
 class StdlibChecker(BaseChecker):
     __implements__ = (IAstroidChecker,)
     name = 'stdlib'
@@ -89,45 +127,6 @@ class StdlibChecker(BaseChecker):
                 infered.qname() == 'datetime.time'):
             self.add_message('boolean-datetime', node=node)
 
-    @staticmethod
-    def _check_mode_str(mode):
-        # check type
-        cls = str if six.PY3 else basestring
-        if not isinstance(mode, cls):
-            return False
-        # check syntax
-        modes = set(mode)
-        _mode = "rwatb+U"
-        if six.PY3:
-            _mode += "x"
-        if modes - set(_mode) or len(mode) > len(modes):
-            return False
-        # check logic
-        creating = False
-        if six.PY3:
-            creating = "x" in modes
-        reading = "r" in modes
-        writing = "w" in modes
-        appending = "a" in modes
-        updating = "+" in modes
-        text = "t" in modes
-        binary = "b" in modes
-        if "U" in modes:
-            if writing or appending or creating and six.PY3:
-                return False
-            reading = True
-        if text and binary:
-            return False
-        total = reading + writing + appending + (creating if six.PY3 else 0)
-        if total > 1:
-            return False
-        if not (reading or writing or appending or creating and six.PY3):
-            return False
-        # 2.x constraints
-        if not six.PY3:
-            if mode[0] not in ("r", "w", "a", "U"):
-                return False
-        return True
 
     def _check_open_mode(self, node):
         """Check that the mode argument of an open or file call is valid."""
@@ -136,7 +135,7 @@ class StdlibChecker(BaseChecker):
             if mode_arg:
                 mode_arg = utils.safe_infer(mode_arg)
                 if (isinstance(mode_arg, astroid.Const)
-                        and not self._check_mode_str(mode_arg.value)):
+                        and not _check_mode_str(mode_arg.value)):
                     self.add_message('bad-open-mode', node=node,
                                      args=(mode_arg.value))
         except (utils.NoSuchArgumentError, TypeError):
@@ -145,4 +144,3 @@ class StdlibChecker(BaseChecker):
 def register(linter):
     """required method to auto register this checker """
     linter.register_checker(StdlibChecker(linter))
-