Rename asset_stream_manager to cdc_stream (#27)

Fixes #13

cdc_stream/background_service_impl.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * 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.
+ */
+
+#ifndef CDC_STREAM_BACKGROUND_SERVICE_IMPL_H_
+#define CDC_STREAM_BACKGROUND_SERVICE_IMPL_H_
+
+#include "absl/status/status.h"
+#include "cdc_stream/background_service_impl.h"
+#include "cdc_stream/session_management_server.h"
+#include "grpcpp/grpcpp.h"
+#include "proto/background_service.grpc.pb.h"
+
+namespace cdc_ft {
+
+// Implements a service to manage a background process as a server.
+// This service is owned by SessionManagementServer.
+class BackgroundServiceImpl final
+    : public backgroundservice::BackgroundService::Service {
+ public:
+  using ExitRequest = backgroundservice::ExitRequest;
+  using ExitResponse = backgroundservice::ExitResponse;
+  using GetPidRequest = backgroundservice::GetPidRequest;
+  using GetPidResponse = backgroundservice::GetPidResponse;
+  using EmptyProto = google::protobuf::Empty;
+
+  BackgroundServiceImpl();
+  ~BackgroundServiceImpl();
+
+  // Exit callback gets called from the Exit() RPC.
+  using ExitCallback = std::function<absl::Status()>;
+  void SetExitCallback(ExitCallback exit_callback);
+
+  grpc::Status Exit(grpc::ServerContext* context, const ExitRequest* request,
+                    ExitResponse* response) override;
+
+  grpc::Status GetPid(grpc::ServerContext* context,
+                      const GetPidRequest* request,
+                      GetPidResponse* response) override;
+
+  grpc::Status HealthCheck(grpc::ServerContext* context,
+                           const EmptyProto* request,
+                           EmptyProto* response) override;
+
+ private:
+  ExitCallback exit_callback_;
+};
+
+}  // namespace cdc_ft
+
+#endif  // CDC_STREAM_BACKGROUND_SERVICE_IMPL_H_