[Bf-blender-cvs] [8c447932287] master: Implement C++ methods for DNA structures
Sergey Sharybin
noreply at git.blender.org
Fri Mar 25 10:46:38 CET 2022
Commit: 8c44793228750537c08ea7b19fc18df0138f9501
Author: Sergey Sharybin
Date: Wed Mar 23 12:05:47 2022 +0100
Branches: master
https://developer.blender.org/rB8c44793228750537c08ea7b19fc18df0138f9501
Implement C++ methods for DNA structures
This change makes it possible to add implementation of common
C++ methods for DNA structures which helps ensuring unsafe
operations like shallow copy are done explicitly.
For example, creating a shallow copy used to be:
Object temp_object = *input_object;
In the C++ context it was seen like the temp_object is
properly decoupled from the input object, while in the
reality is it not. Now this code becomes:
Object temp_object = blender::dna::shallow_copy(*input_object);
The copy and move constructor and assignment operators are
now explicitly disabled.
Other than a more explicit resource management this change
also solves a lot of warnings generated by the implicitly
defined copy constructors w.r.t dealing with deprecated fields.
These warnings were generated by Apple Clang when a shallow
object copy was created via implicitly defined copy constructor.
In order to enable C++ methods for DNA structures a newly added
macro `DNA_DEFINE_CXX_METHODS()` is to be used:
tpyedef struct Object {
DNA_DEFINE_CXX_METHODS(Object)
...
} Object;
For the shallow copy use `blender::dna::shallow_copy()`.
The implementation of the memcpy is hidden via an internal DNA
function to avoid pulling `string.h` into every DNA header.
This means that the solution does not affect on the headers
dependencies.
---
Ideally `DNA_shallow_copy` would be defined in a more explicit
header, but don;t think we have a suitable one already. Maybe
we can introduce `DNA_access.h` ?
Differential Revision: https://developer.blender.org/D14427
===================================================================
M source/blender/blenkernel/intern/mesh_convert.cc
M source/blender/blenkernel/intern/object.cc
M source/blender/depsgraph/intern/depsgraph_query_iter.cc
M source/blender/editors/object/object_transform.cc
M source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
M source/blender/makesdna/DNA_defs.h
M source/blender/makesdna/DNA_object_types.h
M source/blender/makesdna/intern/dna_utils.c
M source/blender/makesdna/intern/makesdna.c
===================================================================
diff --git a/source/blender/blenkernel/intern/mesh_convert.cc b/source/blender/blenkernel/intern/mesh_convert.cc
index 40c6fbcf67e..1be2d06ce61 100644
--- a/source/blender/blenkernel/intern/mesh_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_convert.cc
@@ -910,7 +910,8 @@ static void curve_to_mesh_eval_ensure(Object &object)
*
* So we create temporary copy of the object which will use same data as the original bevel, but
* will have no modifiers. */
- Object bevel_object = {{nullptr}};
+ Object bevel_object;
+ memset(&bevel_object, 0, sizeof(bevel_object));
if (curve.bevobj != nullptr) {
memcpy(&bevel_object, curve.bevobj, sizeof(bevel_object));
BLI_listbase_clear(&bevel_object.modifiers);
@@ -919,7 +920,8 @@ static void curve_to_mesh_eval_ensure(Object &object)
}
/* Same thing for taper. */
- Object taper_object = {{nullptr}};
+ Object taper_object;
+ memset(&taper_object, 0, sizeof(taper_object));
if (curve.taperobj != nullptr) {
memcpy(&taper_object, curve.taperobj, sizeof(taper_object));
BLI_listbase_clear(&taper_object.modifiers);
diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc
index 1e3b5d77fa7..6d1eac5af49 100644
--- a/source/blender/blenkernel/intern/object.cc
+++ b/source/blender/blenkernel/intern/object.cc
@@ -3946,7 +3946,7 @@ bool BKE_object_minmax_dupli(Depsgraph *depsgraph,
/* pass */
}
else {
- Object temp_ob = *dob->ob;
+ Object temp_ob = blender::dna::shallow_copy(*dob->ob);
/* Do not modify the original boundbox. */
temp_ob.runtime.bb = nullptr;
BKE_object_replace_data_on_shallow_copy(&temp_ob, dob->ob_data);
diff --git a/source/blender/depsgraph/intern/depsgraph_query_iter.cc b/source/blender/depsgraph/intern/depsgraph_query_iter.cc
index 5788e8efa07..d5566e4be98 100644
--- a/source/blender/depsgraph/intern/depsgraph_query_iter.cc
+++ b/source/blender/depsgraph/intern/depsgraph_query_iter.cc
@@ -167,7 +167,7 @@ bool deg_iterator_duplis_step(DEGObjectIterData *data)
/* Temporary object to evaluate. */
Object *dupli_parent = data->dupli_parent;
Object *temp_dupli_object = &data->temp_dupli_object;
- *temp_dupli_object = *dob->ob;
+ *temp_dupli_object = blender::dna::shallow_copy(*dob->ob);
temp_dupli_object->base_flag = dupli_parent->base_flag | BASE_FROM_DUPLI;
temp_dupli_object->base_local_view_bits = dupli_parent->base_local_view_bits;
temp_dupli_object->runtime.local_collections_bits =
diff --git a/source/blender/editors/object/object_transform.cc b/source/blender/editors/object/object_transform.cc
index 24425b5a991..afd2c048379 100644
--- a/source/blender/editors/object/object_transform.cc
+++ b/source/blender/editors/object/object_transform.cc
@@ -1695,13 +1695,13 @@ static void object_apply_rotation(Object *ob, const float rmat[3][3])
static void object_apply_location(Object *ob, const float loc[3])
{
/* quick but weak */
- Object ob_prev = *ob;
+ Object ob_prev = blender::dna::shallow_copy(*ob);
float mat[4][4];
copy_m4_m4(mat, ob->obmat);
copy_v3_v3(mat[3], loc);
BKE_object_apply_mat4(ob, mat, true, true);
copy_v3_v3(mat[3], ob->loc);
- *ob = ob_prev;
+ *ob = blender::dna::shallow_copy(ob_prev);
copy_v3_v3(ob->loc, mat[3]);
}
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc b/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
index aa63e65b1e8..8c9b04a5ac3 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
@@ -33,7 +33,7 @@ OBJMesh::OBJMesh(Depsgraph *depsgraph, const OBJExportParams &export_params, Obj
{
/* We need to copy the object because it may be in temporary space. */
Object *obj_eval = DEG_get_evaluated_object(depsgraph, mesh_object);
- export_object_eval_ = *obj_eval;
+ export_object_eval_ = dna::shallow_copy(*obj_eval);
export_mesh_eval_ = export_params.apply_modifiers ?
BKE_object_get_evaluated_mesh(&export_object_eval_) :
BKE_object_get_pre_modified_mesh(&export_object_eval_);
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
diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h
index 9e0bf7dcc5a..c3708e25ee7 100644
--- a/source/blender/makesdna/DNA_object_types.h
+++ b/source/blender/makesdna/DNA_object_types.h
@@ -233,6 +233,8 @@ enum eObjectLineArt_Flags {
};
typedef struct Object {
+ DNA_DEFINE_CXX_METHODS(Object)
+
ID id;
/** Animation data (must be immediately after id for utilities to use it). */
struct AnimData *adt;
diff --git a/source/blender/makesdna/intern/dna_utils.c b/source/blender/makesdna/intern/dna_utils.c
index 8c86ef69ebd..560b91b925e 100644
--- a/source/blender/makesdna/intern/dna_utils.c
+++ b/source/blender/makesdna/intern/dna_utils.c
@@ -308,3 +308,15 @@ const char *DNA_struct_rename_legacy_hack_alias_from_static(const char *name)
}
/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Internal helpers for C++
+ * \{ */
+
+void _DNA_internal_memcpy(void *dst, const void *src, size_t size);
+void _DNA_internal_memcpy(void *dst, const void *src, const size_t size)
+{
+ memcpy(dst, src, size);
+}
+
+/** \} */
diff --git a/source/blender/makesdna/intern/makesdna.c b/source/blender/makesdna/intern/makesdna.c
index 0d2f265a9b5..12ec7262906 100644
--- a/source/blender/makesdna/intern/makesdna.c
+++ b/source/blender/makesdna/intern/makesdna.c
@@ -620,6 +620,7 @@ static int preprocess_include(char *maindata, const int maindata_len)
int newlen = 0;
comment = 0;
a = maindata_len;
+ bool skip_until_closing_brace = false;
while (a--) {
if (cp[0] == '/' && cp[1] == '*') {
@@ -646,6 +647,17 @@ static int preprocess_include(char *maindata, const int maindata_len)
a -= 13;
cp += 13;
}
+ else if (match_identifier(cp, "DNA_DEFINE_CXX_METHODS")) {
+ /* single values are skipped already, so decrement 1 less */
+ a -= 21;
+ cp += 21;
+ skip_until_closing_brace = true;
+ }
+ else if (skip_until_closing_brace) {
+ if (cp[0] == ')') {
+ skip_until_closing_brace = false;
+ }
+ }
else {
md[0] = cp[0];
md++;
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