Add BMediaRoster::IsRunning

* This function is provided to check
  if media services are running.

headers/os/media/MediaRoster.h

@@ -41,6 +41,9 @@ public:
 				// already. It is not thread safe if you call Roster() at the
 				// same time.
 
+	// Check if the media services are running.
+	static bool					IsRunning();
+
 	// Getting common instances of system nodes:
 			status_t			GetVideoInput(media_node* _node);
 			status_t			GetAudioInput(media_node* _node);

src/kits/media/MediaRoster.cpp

@@ -52,6 +52,7 @@ char __dont_remove_copyright_from_binary[] = "Copyright (c) 2002-2006 Marcus "
 #include <MimeType.h>
 #include <OS.h>
 #include <ParameterWeb.h>
+#include <Roster.h>
 #include <StopWatch.h>
 #include <String.h>
 #include <TimeSource.h>
@@ -3217,6 +3218,16 @@ BMediaRoster::GetInstancesFor(media_addon_id addon, int32 flavor,
 }
 
 
+bool
+BMediaRoster::IsRunning()
+{
+	if (be_roster->IsRunning(B_MEDIA_SERVER_SIGNATURE)
+		&& be_roster->IsRunning(B_MEDIA_ADDON_SERVER_SIGNATURE))
+		return true;
+	return false;
+}
+
+
 status_t
 BMediaRoster::SetRealtimeFlags(uint32 enabled)
 {