[Sync] Add SyncEncryptionHandler

sync/syncable/nigori_handler.h

+// Copyright (c) 2012 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.
+
+#ifndef SYNC_SYNCABLE_NIGORI_HANDLER_H_
+#define SYNC_SYNCABLE_NIGORI_HANDLER_H_
+
+#include "sync/internal_api/public/base/model_type.h"
+
+namespace sync_pb {
+class NigoriSpecifics;
+}
+
+namespace syncer {
+namespace syncable {
+
+// Sync internal interface for dealing with nigori node and querying
+// the current set of encrypted types. Not thread safe, so a sync transaction
+// must be held by a caller whenever invoking methods.

[tim (not reviewing), 2012/08/14 02:32:20]

Convention would be to have a transaction pointer passed in and dchecked.  Is
that infeasible?

[Nicolas Zea, 2012/08/14 23:24:51]

Done.

+class NigoriHandler {
+ public:
+  NigoriHandler();
+  virtual ~NigoriHandler();
+
+  // Apply a nigori node update, updating the internal encryption state
+  // accordingly.
+  virtual void UpdateFromNigori(const sync_pb::NigoriSpecifics& nigori) = 0;

[tim (not reviewing), 2012/08/14 02:32:20]

I think ApplyNigoriUpdate is a better name here... UpdateFromNigori on a pure
virtual interface doesn't tell you much.  It's also consistent with the
ApplyNigoriUpdate method on SyncEncryptionHandlerImpl, which this winds up
getting to -- maybe that one should be called ApplyNigoriUpdateImpl, and have
that be called by its implementation of ApplyNigoriUpdate (and the ReloadNigori
case).  

I'd also change the name on Cryptographer, so it's easier to connect the
which-code-leads-to-what dots in our brain :)

[Nicolas Zea, 2012/08/14 23:24:51]

Done for first part. What do you mean by change the name on cryptographer
though?

+
+  // Store the current encrypt everything/encrypted types state into |nigori|.
+  virtual void UpdateNigoriFromEncryptedTypes(
+      sync_pb::NigoriSpecifics* nigori) const = 0;
+
+  // Returns the set of currently encrypted types.
+  virtual ModelTypeSet GetEncryptedTypes() const = 0;
+};
+
+}  // namespace syncable
+}  // namespace syncer
+
+#endif  // SYNC_SYNCABLE_NIGORI_HANDLER_H_