MonitorSignal low-level wrapper introduced

chromeos/dbus/dbus.h

Index: chromeos/dbus/dbus.h
diff --git a/chromeos/dbus/dbus.h b/chromeos/dbus/dbus.h
index 025802160d4f4155ef60a9ea3522171b7fbd7a7b..d7da89dfaac411ee92df5b42578aec9d864a93e1 100644
--- a/chromeos/dbus/dbus.h
+++ b/chromeos/dbus/dbus.h
@@ -14,6 +14,9 @@
 #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
@@ -416,6 +419,32 @@ 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() : interface_(NULL), signal_(NULL) {}
+  ~SignalWatcher();
+  void StartMonitoring(const char* interface, const char* 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);
+  const char* interface_;

[Daniel Erat, 2011/02/11 18:31:45]

use std::string instead for these so you don't crash if the caller frees the
strings that it passes in to the c'tor.  (this whole file should be written to
use std::string instead, but that's another change.)

[glotov, 2011/02/11 18:55:49]

Done.

+  const char* signal_;
+};
+
 }  // namespace dbus
 }  // namespace chromeos