diff options
Diffstat (limited to 'source/blender/makesdna/DNA_defs.h')
-rw-r--r-- | source/blender/makesdna/DNA_defs.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/source/blender/makesdna/DNA_defs.h b/source/blender/makesdna/DNA_defs.h index b4230209dd5..283eacf1a16 100644 --- a/source/blender/makesdna/DNA_defs.h +++ b/source/blender/makesdna/DNA_defs.h @@ -46,3 +46,84 @@ /* non-id name variables should use this length */ #define MAX_NAME 64 + +/* #DNA_DEFINE_CXX_METHODS is used to define C++ methods which are needed for proper/safe resource + * management, making unsafe (from an ownership perspective: i.e. pointers which sometimes needs to + * be set to nullptr on copy, sometimes needs to be dupalloc-ed) operations explicit, and taking + * care of compiler specific warnings when dealing with members marked with DNA_DEPRECATED. + * + * The `class_name` argument is to match the structure name the macro is used from. + * + * Typical usage example: + * + * typedef struct Object { + * DNA_DEFINE_CXX_METHODS(Object) + * } Object; + */ +#ifndef __cplusplus +# define DNA_DEFINE_CXX_METHODS(class_name) +#else + +/* Forward-declared here since there is no simple header file to be pulled for this functionality. + * Avoids pulling `string.h` from this header to get access to #memcpy. */ +extern "C" void _DNA_internal_memcpy(void *dst, const void *src, size_t size); + +namespace blender::dna::internal { + +template<class T> class ShallowDataConstRef { + public: + constexpr explicit ShallowDataConstRef(const T &ref) : ref_(ref) + { + } + + inline const T *get_pointer() const + { + return &ref_; + } + + private: + const T &ref_; +}; + +} // namespace blender::dna::internal + +# define DNA_DEFINE_CXX_METHODS(class_name) \ + class_name() = default; \ + ~class_name() = default; \ + /* Delete copy and assignment, which are not safe for resource ownership. */ \ + class_name(const class_name &other) = delete; \ + class_name(class_name &&other) noexcept = delete; \ + class_name &operator=(const class_name &other) = delete; \ + class_name &operator=(class_name &&other) = delete; \ + /* Support for shallow copy. */ \ + class_name(const blender::dna::internal::ShallowDataConstRef<class_name> ref) \ + { \ + _DNA_internal_memcpy(this, ref.get_pointer(), sizeof(class_name)); \ + } \ + class_name &operator=(const blender::dna::internal::ShallowDataConstRef<class_name> ref) \ + { \ + if (this != ref.get_pointer()) { \ + _DNA_internal_memcpy(this, ref.get_pointer(), sizeof(class_name)); \ + } \ + return *this; \ + } + +namespace blender::dna { + +/* Creates shallow copy of the given object. + * The entire object is copied as-is using memory copy. + * + * Typical usage: + * Object temp_object = blender::dna::shallow_copy(*input_object); + * + * From the implementation detail go via copy constructor/assign operator defined in the structure. + */ +template<class T> +[[nodiscard]] inline internal::ShallowDataConstRef<T> shallow_copy(const T &other) +{ + return internal::ShallowDataConstRef(other); +} + +} // namespace blender::dna + +#endif |