Adding the frozendict module

Upstream: https://github.com/slezica/python-frozendict

python/ycm/frozendict.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python
+#
+# Source: https://github.com/slezica/python-frozendict
+#
+# Copyright (c) 2012 Santiago Lezica
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+import collections, operator
+
+class frozendict(collections.Mapping):
+
+    def __init__(self, *args, **kwargs):
+        self.__dict = dict(*args, **kwargs)
+        self.__hash = None
+
+    def __getitem__(self, key):
+        return self.__dict[key]
+
+    def copy(self, **add_or_replace):
+        new = frozendict(self)
+        new.__dict.update(add_or_replace) # Feels like cheating
+        return new
+
+    def __iter__(self):
+        return iter(self.__dict)
+
+    def __len__(self):
+        return len(self.__dict)
+
+    def __repr__(self):
+        return '<frozendict %s>' % repr(self.__dict)
+
+    def __hash__(self):
+        if self.__hash is None:
+            self.__hash = reduce(operator.xor, map(hash, self.iteritems()), 0)
+
+        return self.__hash

python/ycm/user_options_store.py

@@ -17,7 +17,7 @@
 # You should have received a copy of the GNU General Public License
 # along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
 
-from frozendict import frozendict
+from ycm.frozendict import frozendict
 
 _USER_OPTIONS = {}