// A Simple handle class that uses copying.

#include <string>
#include <iostream>

template < typename T >
class handle {

  public:

    handle() : tp(0) { }
    handle(T * tp) : tp(tp) { }
  
   ~handle(void) { 
     delete tp; 
     }

    handle(const handle & th) : tp(th.tp ? th.tp->clone() : 0) { }

    handle & operator = (const handle & th) {
      if (this != &th) {
	delete tp;
	tp = th.tp ? th.tp->clone() : 0;
	}
      return *this;
      }

    operator bool (void) const {
      return tp;
      }

    T & operator * (void) {
      assert(tp);
      return *tp;
      }

    T * operator -> (void) {
      assert(tp);
      return tp;
      }

  private:

    T * tp;
  };


struct widget {

  widget(std::string str) : str(str) { 
    std::cerr << "Creating a " << str << " widget.\n"; 
    }
 ~widget() { 
    std::cerr << "Deleting a " << str << " widget.\n";
    }
  widget * clone(void) const { return 0; }

  const std::string str;
  };


int main() {
  handle<widget> w1h = new widget("red");
  if (w1h) {
    handle<widget> w2h = new widget("blue");
    try {
      handle<widget> w3h = new widget("green");
      throw(1);
      }
    catch (int) { }
    }
  }

// $Log: c-handle.cc,v $
// Revision 1.1  2002/04/25 13:03:45  rclayton
// Initial revision
//