OrphanHandle.h

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#ifndef DataFormats_Common_OrphanHandle_h
#define DataFormats_Common_OrphanHandle_h
 
/*----------------------------------------------------------------------
  
OrphanHandle: Non-owning "smart pointer" for reference to EDProducts.
 
This is a very preliminary version, and lacks safety features and elegance.
 
If the pointed-to EDProduct is destroyed, use of the OrphanHandle
becomes undefined. There is no way to query the OrphanHandle to
discover if this has happened.
 
OrphanHandles can have:
  -- Product pointer null and id == 0;
  -- Product pointer valid and id != 0;
 
To check validity, one can use the isValid() function.
 
----------------------------------------------------------------------*/
 
#include "DataFormats/Common/interface/OrphanHandleBase.h"
 
namespace edm {
  template <typename T>
  class OrphanHandle : public OrphanHandleBase {
  public:
    typedef T element_type;
 
    // Default constructed handles are invalid.
    OrphanHandle();
 
    OrphanHandle(T const* prod, ProductID const& id);
 
    ~OrphanHandle();
 
    T const* product() const;
    T const* operator->() const;  // alias for product()
    T const& operator*() const;
 
  private:
  };
 
  template <class T>
  OrphanHandle<T>::OrphanHandle() : OrphanHandleBase() {}
 
  template <class T>
  OrphanHandle<T>::OrphanHandle(T const* prod, ProductID const& theId) : OrphanHandleBase(prod, theId) {}
 
  template <class T>
  OrphanHandle<T>::~OrphanHandle() {}
 
  template <class T>
  T const* OrphanHandle<T>::product() const {
    return static_cast<T const*>(productStorage());
  }
 
  template <class T>
  T const* OrphanHandle<T>::operator->() const {
    return product();
  }
 
  template <class T>
  T const& OrphanHandle<T>::operator*() const {
    return *product();
  }
 
}  // namespace edm
#endif