libcamera: event_dispatcher: Add interrupt() function

The new interrupt() function allows interrupting in-progress blocking
processEvents() calls. This is useful to stop running event loops.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

include/libcamera/event_dispatcher.h

@@ -26,6 +26,8 @@ public:
 	virtual void unregisterTimer(Timer *timer) = 0;
 
 	virtual void processEvents() = 0;
+
+	virtual void interrupt() = 0;
 };
 
 } /* namespace libcamera */