Move chromeos symbols into brillo namespace

And move the include files into "brillo" directory instead of "chromeos"

BUG: 24872993
TEST=built aosp and brillo and unit tests pass on dragonoboard

Change-Id: Ieb979d1ebd3152921d36cd15acbd6247f02aae69

1 files changed, 68 insertions, 0 deletions

diff --git a/brillo/dbus/dbus_signal_handler.h b/brillo/dbus/dbus_signal_handler.h
new file mode 100644
index 0000000..dfa1e78
--- /dev/null
+++ b/brillo/dbus/dbus_signal_handler.h
@@ -0,0 +1,68 @@
+// Copyright 2014 The Chromium OS 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 LIBCHROMEOS_BRILLO_DBUS_DBUS_SIGNAL_HANDLER_H_
+#define LIBCHROMEOS_BRILLO_DBUS_DBUS_SIGNAL_HANDLER_H_
+
+#include <string>
+
+#include <brillo/bind_lambda.h>
+#include <brillo/dbus/dbus_param_reader.h>
+#include <dbus/message.h>
+#include <dbus/object_proxy.h>
+
+namespace brillo {
+namespace dbus_utils {
+
+// brillo::dbus_utils::ConnectToSignal() is a helper function similar to
+// dbus::ObjectProxy::ConnectToSignal() but the |signal_callback| is an actual
+// C++ signal handler with expected signal parameters as native method args.
+//
+// brillo::dbus_utils::ConnectToSignal() actually registers a stub signal
+// handler with D-Bus which has a standard signature that matches
+// dbus::ObjectProxy::SignalCallback.
+//
+// When a D-Bus signal is emitted, the stub handler is invoked, which unpacks
+// the expected parameters from dbus::Signal message and then calls
+// |signal_callback| with unpacked arguments.
+//
+// If the signal message doesn't contain correct number or types of arguments,
+// an error message is logged to the system log and the signal is ignored
+// (|signal_callback| is not invoked).
+template<typename... Args>
+void ConnectToSignal(
+    dbus::ObjectProxy* object_proxy,
+    const std::string& interface_name,
+    const std::string& signal_name,
+    base::Callback<void(Args...)> signal_callback,
+    dbus::ObjectProxy::OnConnectedCallback on_connected_callback) {
+  // DBusParamReader::Invoke() needs a functor object, not a base::Callback.
+  // Wrap the callback with lambda so we can redirect the call.
+  auto signal_callback_wrapper = [signal_callback](const Args&... args) {
+    if (!signal_callback.is_null()) {
+      signal_callback.Run(args...);
+    }
+  };
+
+  // Raw signal handler stub method. When called, unpacks the signal arguments
+  // from |signal| message buffer and redirects the call to
+  // |signal_callback_wrapper| which, in turn, would call the user-provided
+  // |signal_callback|.
+  auto dbus_signal_callback = [signal_callback_wrapper](dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    DBusParamReader<false, Args...>::Invoke(
+        signal_callback_wrapper, &reader, nullptr);
+  };
+
+  // Register our stub handler with D-Bus ObjectProxy.
+  object_proxy->ConnectToSignal(interface_name,
+                                signal_name,
+                                base::Bind(dbus_signal_callback),
+                                on_connected_callback);
+}
+
+}  // namespace dbus_utils
+}  // namespace brillo
+
+#endif  // LIBCHROMEOS_BRILLO_DBUS_DBUS_SIGNAL_HANDLER_H_