Обработка событий в С++

#ifndef _SIGSLOT_h_ 

#define _SIGSLOT_h_ 

// sigslot.h – autor Kluev Alexander kluev@pragmaworks.com 

template  

class signal; 

class slot {

 friend class signal_base; 

 slot *_prev;

 slot *_next;

 struct Thunk {};

 typedef void (Thunk::*Func)();

 Thunk *_trg;

 Func _mfn;

public:

 slot(): _trg(0), _mfn(0), _prev(0), _next(0) {}

 ~slot() {clear();} 

public:

 void clear() {

  if (_next) _next->_prev = _prev; 

  if (_prev) _prev->_next = _next; 

  _prev = _next = 0;

 }

 template 

 void init(signal&sig, void (Owner::*mpfn)(Arg), Owner *This) {

  clear();

 _trg = (Thunk*)This;

 _mfn = (Func)mpfn;

   sig._add(*this);

 }

 template 

 void init(signal&sig, void (Owner::*mpfn)(), Owner *This) {

  clear();

 _trg = (Thunk*)This;

 _mfn = (Func)mpfn; sig._add(*this);

 } 

private:

 template 

 void _call(Arg a) {

  typedef void (Thunk::*XFunc)(Arg);

 XFunc f = (XFunc)_mfn;

 (_trg->*f)(a);

 }

 void _call() {

  (_trg->*_mfn)();

 }

};

class signal_base {

protected:

 friend class slot;

 slot _head;

 void _add(slot&s) {

  s._prev =&_head;

 s._next = _head._next;

 if (_head._next) _head._next->_prev =&s;

 _head._next =&s;

 }

 template 

 void _raise(Arg a) {

  slot *p = _head._next;

 while (p) {

  p->_call(a);

   p = p->_next;

  }

 }

 void _raise() {

  slot *p = _head._next;

 while (p) {

  p->_call();

   p = p->_next;

  }

 }

public:

 ~signal_base() {

  clear();

 } 

public:

 void clear() {

  while (_head._next) _head._next->clear();

 }

};

template  

class signal: public signal_base {

public:

 void raise(Arg);

};

typedef void VOID;

template <> 

void signal::raise() {

 signal_base::_raise();

} 

template  

void signal::raise(Arg a) {

 signal_base::_raise(a);

}

 #endif // _SIGSLOT_h_