[Sync] Add support for performing a GetKey on startup.

sync/engine/get_key_command.cc

+// 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.
+
+#include "sync/engine/get_key_command.h"
+
+#include "sync/engine/syncer_proto_util.h"
+#include "sync/protocol/sync.pb.h"
+#include "sync/sessions/sync_session.h"
+#include "sync/syncable/directory.h"
+#include "sync/syncable/read_transaction.h"
+#include "sync/util/cryptographer.h"
+
+using sync_pb::ClientToServerMessage;
+using sync_pb::ClientToServerResponse;
+
+namespace syncer {
+
+using sessions::SyncSession;
+
+GetKeyCommand::GetKeyCommand() {}
+
+GetKeyCommand::~GetKeyCommand() {}
+
+SyncerError GetKeyCommand::ExecuteImpl(SyncSession* session) {
+  ClientToServerMessage client_to_server_message;
+  ClientToServerResponse server_to_client_response;
+
+  if (!session->context()->keystore_encryption_enabled())
+    return SYNCER_OK;
+
+  SyncerProtoUtil::SetProtocolVersion(&client_to_server_message);

[tim (not reviewing), 2012/07/19 21:42:03]

Can we move this to PostClientToServerMessage?

[Nicolas Zea, 2012/07/24 22:51:24]

Added TODO to do that in a follow-up patch.

+  client_to_server_message.set_share(session->context()->account_name());
+  client_to_server_message.set_message_contents(
+      sync_pb::ClientToServerMessage::GET_ENCRYPTION_KEY);
+  client_to_server_message.mutable_get_encryption_key();
+
+  SyncerProtoUtil::AddRequestBirthday(session->context()->directory(),
+                                      &client_to_server_message);
+
+  SyncerError result = SyncerProtoUtil::PostClientToServerMessage(
+      client_to_server_message,
+      &server_to_client_response,
+      session);
+
+  DVLOG(2) << SyncerProtoUtil::ClientToServerResponseDebugString(
+      server_to_client_response);
+
+  if (result != SYNCER_OK) {
+    LOG(ERROR) << "PostClientToServerMessage() failed during GetKey.";
+    return result;
+  }
+
+  syncable::Directory* dir = session->context()->directory();
+  syncable::ReadTransaction trans(FROM_HERE, dir);
+  Cryptographer* cryptographer =
+      session->context()->directory()->GetCryptographer(&trans);
+  bool success = cryptographer->SetKeystoreKey(
+      server_to_client_response.get_encryption_key().key());
+
+  DVLOG(1) << "GetKey returned key of length "
+           << server_to_client_response.get_encryption_key().key().length()
+           << ". Cryptographer keystore key "
+           << (success ? "" : "not ") << "updated.";
+
+  return (success ? SYNCER_OK : SERVER_RESPONSE_VALIDATION_FAILED);
+}
+
+}  // namespace syncer