Check in the thirdparty libs needed for webkitpy.

Tools/Scripts/webkitpy/thirdparty/webpagereplay/persistentmixin.py

+#!/usr/bin/env python
+# Copyright 2010 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import cPickle
+import os
+
+class PersistentMixin:
+  """Mixin class which provides facilities for persisting and restoring."""
+
+  @classmethod
+  def AssertWritable(cls, filename):
+    """Raises an IOError if filename is not writable."""
+    persist_dir = os.path.dirname(os.path.abspath(filename))
+    if not os.path.exists(persist_dir):
+      raise IOError('Directory does not exist: %s' % persist_dir)
+    if os.path.exists(filename):
+      if not os.access(filename, os.W_OK):
+        raise IOError('Need write permission on file: %s' % filename)
+    elif not os.access(persist_dir, os.W_OK):
+      raise IOError('Need write permission on directory: %s' % persist_dir)
+
+  @classmethod
+  def Load(cls, filename):
+    """Load an instance from filename."""
+    return cPickle.load(open(filename, 'rb'))
+
+  def Persist(self, filename):
+    """Persist all state to filename."""
+    cPickle.dump(self, open(filename, 'wb'), cPickle.HIGHEST_PROTOCOL)