Add a method to check if a D-Bus service has an owner. Use it for mtpd.

dbus/object_proxy.h

 // Copyright (c) 2012 The Chromium 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 DBUS_OBJECT_PROXY_H_
 #define DBUS_OBJECT_PROXY_H_
 
 #include <dbus/dbus.h>
 
 #include <map>
@@ skipping 46 matching lines @@
   // The constants correspond to DBUS_TIMEOUT_USE_DEFAULT and
   // DBUS_TIMEOUT_INFINITE. Here we use literal numbers instead of these
   // macros as these aren't defined with D-Bus earlier than 1.4.12.
   enum {
     TIMEOUT_USE_DEFAULT = -1,
     TIMEOUT_INFINITE = 0x7fffffff,
   };
 
   // Called when an error response is returned or no response is returned.
   // Used for CallMethodWithErrorCallback().
-  typedef base::Callback<void(ErrorResponse*)> ErrorCallback;
+  typedef base::Callback<void(ErrorResponse* error_response)> ErrorCallback;
 
   // Called when the response is returned. Used for CallMethod().
-  typedef base::Callback<void(Response*)> ResponseCallback;
+  typedef base::Callback<void(Response* response)> ResponseCallback;
 
   // Called when a signal is received. Signal* is the incoming signal.
-  typedef base::Callback<void (Signal*)> SignalCallback;
+  typedef base::Callback<void (Signal* signal)> SignalCallback;
 
   // Called when the object proxy is connected to the signal.
   // Parameters:
   // - the interface name.
   // - the signal name.
   // - whether it was successful or not.
   typedef base::Callback<void (const std::string&, const std::string&, bool)>
       OnConnectedCallback;
 
   // Calls the method of the remote object and blocks until the response
@@ skipping 62 matching lines @@
   // the origin thread when D-Bus system sends "NameOwnerChanged" for the name
   // represented by |service_name_|.
   virtual void SetNameOwnerChangedCallback(SignalCallback callback);
 
   // Detaches from the remote object. The Bus object will take care of
   // detaching so you don't have to do this manually.
   //
   // BLOCKING CALL.
   virtual void Detach();
 
+  // Convenient form of CallMethodAndBlock() to call
+  // org.freedesktop.DBus.GetNameOwner for the given |service_name|.
+  // Returns true if |service_name| has an owner.
+  //
+  // BLOCKING CALL.
+  static bool ServiceHasOwner(dbus::Bus* bus, const std::string& service_name);

[satorux1, 2013/04/30 01:53:10]

Looks rather awkward to have this in ObjectProxy as a static member function.
Maybe move this to bus.h as a non-static member function?

+
   // Returns an empty callback that does nothing. Can be used for
   // CallMethod().
   static ResponseCallback EmptyResponseCallback();
 
  protected:
   // This is protected, so we can define sub classes.
   virtual ~ObjectProxy();
 
  private:
   friend class base::RefCountedThreadSafe<ObjectProxy>;
@@ skipping 116 matching lines @@
 
   // Known name owner of the well-known bus name represnted by |service_name_|.
   std::string service_name_owner_;
 
   DISALLOW_COPY_AND_ASSIGN(ObjectProxy);
 };
 
 }  // namespace dbus
 
 #endif  // DBUS_OBJECT_PROXY_H_