Docserver: Persist stat cache for versioned file systems

chrome/common/extensions/docs/server2/commit_tracker.py

Index: chrome/common/extensions/docs/server2/commit_tracker.py
diff --git a/chrome/common/extensions/docs/server2/commit_tracker.py b/chrome/common/extensions/docs/server2/commit_tracker.py
new file mode 100644
index 0000000000000000000000000000000000000000..53bb90c9cd6306cb043dfc417797af951ae42f28
--- /dev/null
+++ b/chrome/common/extensions/docs/server2/commit_tracker.py
@@ -0,0 +1,21 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from object_store_creator import ObjectStoreCreator
+from future import Future
+
+
+class CommitTracker(object):
+  '''Utility class for managing and querying the storage of various named commit
+  IDs.'''
+  def __init__(self, object_store_creator):
+    # The object store should never be created empty since the sole purpose of
+    # this tracker is to persist named commit data across requests.
+    self._store = object_store_creator.Create(CommitTracker, start_empty=False)
+
+  def Get(self, key):
+    return self._store.Get(key)
+
+  def Set(self, key, commit):
+    return self._store.Set(key, commit)