Utilities/interface/ConstRespectingPtr.h

0001 #ifndef FWCore_Utilities_ConstRespectingPtr_h
0002 #define FWCore_Utilities_ConstRespectingPtr_h
0003
0004 // Package:     FWCore/Utilities
0005 // Class  :     ConstRespectingPtr
0006 //
0007 /**\class edm::ConstRespectingPtr
0008
0009  Description: When this is a member of a class, const functions of the class
0010 can only call const functions of the object it points at. This aids in using
0011 the compiler to help maintain thread safety of const functions.
0012
0013 Usage: WARNING: member data which uses this class must be made transient in
0014 the classes_def.xml file if it is a member of a persistent class!
0015
0016 */
0017 // Original Author:  W. David Dagenhart
0018 //         Created:  20 March 2014
0019
0020 #include <memory>
0021
0022 #include "FWCore/Utilities/interface/propagate_const.h"
0023
0024 namespace edm {
0025
0026   template <typename T>
0027   class ConstRespectingPtr {
0028   public:
0029     ConstRespectingPtr();
0030     explicit ConstRespectingPtr(T*);
0031     ConstRespectingPtr(ConstRespectingPtr<T> const&) = delete;
0032     ConstRespectingPtr& operator=(ConstRespectingPtr<T> const&) = delete;
0033     ~ConstRespectingPtr();
0034
0035     T const* operator->() const { return m_data; }
0036     T const& operator*() const { return *m_data; }
0037     T const* get() const { return m_data; }
0038
0039     T* operator->() { return m_data; }
0040     T& operator*() { return *m_data; }
0041     T* get() { return m_data; }
0042
0043     bool isSet() const;
0044
0045     void set(std::unique_ptr<T> iNewValue);
0046
0047     T* release();
0048     void reset();
0049
0050   private:
0051     edm::propagate_const<T*> m_data;
0052   };
0053
0054   template <typename T>
0055   ConstRespectingPtr<T>::ConstRespectingPtr() : m_data(nullptr) {}
0056
0057   template <typename T>
0058   ConstRespectingPtr<T>::ConstRespectingPtr(T* v) : m_data(v) {}
0059
0060   template <typename T>
0061   ConstRespectingPtr<T>::~ConstRespectingPtr() {
0062     delete m_data.get();
0063   }
0064
0065   template <typename T>
0066   bool ConstRespectingPtr<T>::isSet() const {
0067     return nullptr != m_data;
0068   }
0069
0070   template <typename T>
0071   void ConstRespectingPtr<T>::set(std::unique_ptr<T> iNewValue) {
0072     delete m_data;
0073     m_data = iNewValue.release();
0074   }
0075
0076   template <typename T>
0077   T* ConstRespectingPtr<T>::release() {
0078     T* tmp = m_data;
0079     m_data = nullptr;
0080     return tmp;
0081   }
0082
0083   template <typename T>
0084   void ConstRespectingPtr<T>::reset() {
0085     delete m_data;
0086     m_data = nullptr;
0087   }
0088 }  // namespace edm
0089 #endif