upload android base code part6

android/system/update_engine/dbus_connection.cc

@@ -0,0 +1,55 @@
+//
+// Copyright (C) 2016 The Android Open Source Project
+//
+// 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.
+//
+
+#include "update_engine/dbus_connection.h"
+
+#include <base/time/time.h>
+
+namespace chromeos_update_engine {
+
+namespace {
+const int kDBusSystemMaxWaitSeconds = 2 * 60;
+
+DBusConnection* dbus_connection_singleton = nullptr;
+}  // namespace
+
+DBusConnection::DBusConnection() {
+  // We wait for the D-Bus connection for up two minutes to avoid re-spawning
+  // the daemon too fast causing thrashing if dbus-daemon is not running.
+  bus_ = dbus_connection_.ConnectWithTimeout(
+      base::TimeDelta::FromSeconds(kDBusSystemMaxWaitSeconds));
+
+  if (!bus_) {
+    // TODO(deymo): Make it possible to run update_engine even if dbus-daemon
+    // is not running or constantly crashing.
+    LOG(FATAL) << "Failed to initialize DBus, aborting.";
+  }
+
+  CHECK(bus_->SetUpAsyncOperations());
+}
+
+const scoped_refptr<dbus::Bus>& DBusConnection::GetDBus() {
+  CHECK(bus_);
+  return bus_;
+}
+
+DBusConnection* DBusConnection::Get() {
+  if (!dbus_connection_singleton)
+    dbus_connection_singleton = new DBusConnection();
+  return dbus_connection_singleton;
+}
+
+}  // namespace chromeos_update_engine