db/upnp: use std::function for the libupnp callback

src/db/upnp/Discovery.cxx

@@ -158,7 +158,7 @@ discoExplorer(void *)
 // mutex just for clarifying the message printing, the workqueue is
 // mt-safe of course.
 static int
-cluCallBack(Upnp_EventType et, void *evp, void *)
+cluCallBack(Upnp_EventType et, void *evp)
 {
 	static Mutex cblock;
 	const ScopeLock protect(cblock);
@@ -231,11 +231,9 @@ UPnPDeviceDirectory::UPnPDeviceDirectory()
 	if (lib == nullptr)
 		return;
 
-	lib->registerHandler(UPNP_DISCOVERY_SEARCH_RESULT, cluCallBack, this);
-	lib->registerHandler(UPNP_DISCOVERY_ADVERTISEMENT_ALIVE,
-			     cluCallBack, this);
-	lib->registerHandler(UPNP_DISCOVERY_ADVERTISEMENT_BYEBYE,
-			     cluCallBack, this);
+	lib->SetHandler([](Upnp_EventType type, void *event){
+			cluCallBack(type, event);
+		});
 
 	search();
 }

src/db/upnp/upnpplib.cxx

@@ -65,15 +65,6 @@ LibUPnP::LibUPnP()
 	ixmlRelaxParser(1);
 }
 
-void
-LibUPnP::registerHandler(Upnp_EventType et, Upnp_FunPtr handler, void *cookie)
-{
-	if (handler == nullptr)
-		m_handlers.erase(et);
-	else
-		m_handlers.emplace(et, Handler(handler, cookie));
-}
-
 int
 LibUPnP::o_callback(Upnp_EventType et, void* evp, void* cookie)
 {
@@ -83,10 +74,9 @@ LibUPnP::o_callback(Upnp_EventType et, void* evp, void* cookie)
 		ulib = theLib;
 	}
 
-	auto it = ulib->m_handlers.find(et);
-	if (it != ulib->m_handlers.end()) {
-		(it->second.handler)(et, evp, it->second.cookie);
-	}
+	if (ulib->handler)
+		ulib->handler(et, evp);
+
 	return UPNP_E_SUCCESS;
 }
 

src/db/upnp/upnpplib.hxx

@@ -22,24 +22,18 @@
 
 #include "util/Error.hxx"
 
-#include <map>
-
 #include <upnp/upnp.h>
 
+#include <functional>
+
 /** Our link to libupnp. Initialize and keep the handle around */
 class LibUPnP {
-	// A Handler object records the data from registerHandler.
-	class Handler {
-	public:
-		Handler(Upnp_FunPtr h, void *c)
-			: handler(h), cookie(c) {}
-		Upnp_FunPtr handler;
-		void *cookie;
-	};
+	typedef std::function<void(Upnp_EventType type, void *event)> Handler;
 
 	Error init_error;
 	UpnpClient_Handle m_clh;
-	std::map<Upnp_EventType, Handler> m_handlers;
+
+	Handler handler;
 
 	LibUPnP();
 
@@ -65,7 +59,10 @@ public:
 		return init_error;
 	}
 
-	void registerHandler(Upnp_EventType et, Upnp_FunPtr handler, void *cookie);
+	template<typename T>
+	void SetHandler(T &&_handler) {
+		handler = std::forward<T>(_handler);
+	}
 
 	UpnpClient_Handle getclh()
 	{