start of new crossthread-safe design

git-svn-id: svn://localhost/ardour2/trunk@1133 d708f5d6-7413-0410-9779-e7cbd77b26cf

gtk2_ardour/gui_thread.h

@@ -2,6 +2,7 @@
 #define __ardour_gtk_gui_thread_h__
 
 #include <gtkmm2ext/gtk_ui.h>
+#include <pbd/crossthread.h>
 
 #define ENSURE_GUI_THREAD(slot) \
      if (!Gtkmm2ext::UI::instance()->caller_is_ui_thread()) {\
@@ -9,4 +10,8 @@
         return;\
      }
 
+#define GTK_SAFE(theSlot) crossthread_safe (Gtkmm2ext::UI::instance()->thread_id(),\
+					    *Gtkmm2ext::UI::instance(), \
+					    (theSlot))
+
 #endif /* __ardour_gtk_gui_thread_h__ */

libs/gtkmm2ext/gtkmm2ext/gtk_ui.h

@@ -101,6 +101,8 @@ class UI : public Receiver, public AbstractUI<UIRequest>
 
 	bool caller_is_ui_thread ();
 
+	static pthread_t thread_id() { return gui_thread; }
+
 	/* Gtk-UI specific interfaces */
 
 	bool running ();

libs/pbd/pbd/crossthread.h

@@ -0,0 +1,38 @@
+#ifndef __pbd__crossthread_h__
+#define __pbd__crossthread_h__
+
+#include <pbd/abstract_ui.h>
+#include <sigc++/sigc++.h>
+#include <pthread.h>
+
+template<class RequestType> 
+void 
+call_slot_from_thread_or_dispatch_it (pthread_t thread_id, AbstractUI<RequestType>& ui, sigc::slot<void> theSlot)
+{
+	/* when called, this function will determine whether the calling thread
+	   is the same as thread specified by the first argument. if it is,
+	   the we execute the slot. if not, we ask the interface given by the second
+	   argument to call the slot.
+	*/
+
+	if (pthread_self() == thread_id) {
+		theSlot ();
+	} else {
+		ui.call_slot (theSlot);
+	}
+}
+
+template<class RequestType> 
+sigc::slot<void>
+crossthread_safe (pthread_t thread_id, AbstractUI<RequestType>& ui, sigc::slot<void> theSlot)
+{
+	/* this function returns a slot that will ensure that theSlot is either
+	   called by the specified thread or passed to the interface via 
+	   AbstractUI::call_slot().
+	*/
+	   
+	return sigc::bind (sigc::ptr_fun (call_slot_from_thread_or_dispatch_it<RequestType>), 
+			   thread_id, ui, theSlot);
+}
+
+#endif /* __pbd__crossthread_h__ */