MonitorSignal low-level wrapper introduced

chromeos/dbus/dbus.h

 // Copyright (c) 2009 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 CHROMEOS_DBUS_H_
 #define CHROMEOS_DBUS_H_
 
 #include <dbus/dbus-glib.h>
 #include <glib-object.h>
 
 #include <algorithm>
 #include <string>
 
 #include "base/logging.h"
 #include "chromeos/glib/object.h"
 
+struct DBusMessage;
+struct DBusConnection;
+
 namespace chromeos {
 
 // \precondition No functions in the dbus namespace can be called before
 // ::g_type_init();
 
 namespace dbus {
 
 // \brief   BusConnection manages the ref-count for a ::DBusGConnection*.
 //
 // A BusConnection has reference semantics bound to a particular communication
@@ skipping 382 matching lines @@
 
 BusConnection GetPrivateBusConnection(const char* address);
 
 // \brief Sends a signal named |signal_name| with no arguments to the
 // system bus per the given |path| and |interface_name|.
 
 void SendSignalWithNoArgumentsToSystemBus(const char* path,
                                           const char* interface_name,
                                           const char* signal_name);
 
+// \brief Low-level signal monitor base class.
+//
+// Used when there is no definite named signal sender (that Proxy
+// could be used for).
+
+class SignalWatcher {
+ public:
+  SignalWatcher() {}
+  ~SignalWatcher();
+  void StartMonitoring(const std::string& interface, const std::string& signal);
+ private:
+
+  // Callback invoked on the given signal arrival.
+  virtual void OnSignal(DBusMessage* message) = 0;
+
+  // Returns a string matching the D-Bus messages that we want to listen for.
+  std::string GetDBusMatchString() const;
+
+  // A D-Bus message filter to receive signals.
+  static DBusHandlerResult FilterDBusMessage(DBusConnection* dbus_conn,
+                                             DBusMessage* message,
+                                             void* data);
+  std::string interface_;
+  std::string signal_;
+};
+
 }  // namespace dbus
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_H_