libs/pbd/pbd/shiva.h

   1 #ifndef __pbd_shiva_h__
   2 #define __pbd_shiva_h__
   3
   4 #include <sigc++/sigc++.h>
   5
   6 namespace PBD {
   7
   8 template<typename ObjectWithGoingAway, typename ObjectToBeDestroyed>
   9
  10 /* named after the Hindu god Shiva, The Destroyer */
  11
  12 class Shiva {
  13   public:
  14         Shiva (ObjectWithGoingAway& emitter, ObjectToBeDestroyed& receiver) {
  15
  16                 /* if the emitter goes away, destroy the receiver */
  17
  18                 _connection1 = emitter.GoingAway.connect
  19                         (sigc::bind (sigc::mem_fun
  20                                      (*this, &Shiva<ObjectWithGoingAway,ObjectToBeDestroyed>::destroy),
  21                                      &receiver));
  22
  23                 /* if the receiver goes away, forget all this nonsense */
  24
  25                 _connection2 = receiver.GoingAway.connect
  26                         (sigc::mem_fun (*this, &Shiva<ObjectWithGoingAway,ObjectToBeDestroyed>::forget));
  27         }
  28
  29         ~Shiva() {
  30                 forget ();
  31         }
  32
  33   private:
  34         sigc::connection _connection1;
  35         sigc::connection _connection2;
  36
  37         void destroy (ObjectToBeDestroyed* obj) {
  38                 delete obj;
  39                 forget ();
  40         }
  41
  42         void forget () {
  43                 _connection1.disconnect ();
  44                 _connection2.disconnect ();
  45         }
  46
  47 };
  48
  49 }
  50
  51 #endif /* __pbd_shiva_h__ */