[Bf-blender-cvs] [5f40621496e] virtual-array-attributes: add as generic span classe

[Jacques Lucke]

Commit: 5f40621496ebf64ba718206d3b0e0b6e53277723
Author: Jacques Lucke
Date:   Sat Apr 10 18:04:40 2021 +0200
Branches: virtual-array-attributes
https://developer.blender.org/rB5f40621496ebf64ba718206d3b0e0b6e53277723

add as generic span classe

===================================================================

M	source/blender/blenlib/BLI_virtual_array.hh
M	source/blender/functions/FN_generic_virtual_array.hh

===================================================================

diff --git a/source/blender/blenlib/BLI_virtual_array.hh b/source/blender/blenlib/BLI_virtual_array.hh
index dbd98f3a5f5..6f7c42c9bbf 100644
--- a/source/blender/blenlib/BLI_virtual_array.hh
+++ b/source/blender/blenlib/BLI_virtual_array.hh
@@ -446,11 +446,6 @@ class VMutableArray_As_MutableSpan final : public VMutableArray_For_MutableSpan<
     }
   }
 
-  void disable_not_applied_warning()
-  {
-    show_not_applied_warning_ = false;
-  }
-
   ~VMutableArray_As_MutableSpan()
   {
     if (show_not_applied_warning_) {
@@ -469,6 +464,11 @@ class VMutableArray_As_MutableSpan final : public VMutableArray_For_MutableSpan<
     this->set_all(owned_data_);
   }
 
+  void disable_not_applied_warning()
+  {
+    show_not_applied_warning_ = false;
+  }
+
   Span<T> as_span() const
   {
     return this->get_span();
diff --git a/source/blender/functions/FN_generic_virtual_array.hh b/source/blender/functions/FN_generic_virtual_array.hh
index 6a877c622f9..cfb89c05261 100644
--- a/source/blender/functions/FN_generic_virtual_array.hh
+++ b/source/blender/functions/FN_generic_virtual_array.hh
@@ -233,7 +233,7 @@ class GVArray_For_Empty : public GVArray {
 
 class GVMutableArray_For_GMutableSpan : public GVMutableArray {
  protected:
-  void *data_;
+  void *data_ = nullptr;
   const int64_t element_size_;
 
  public:
@@ -244,7 +244,18 @@ class GVMutableArray_For_GMutableSpan : public GVMutableArray {
   {
   }
 
+  /* When this constructor is used, the #set_span_start method has to be used as well. */
+  GVMutableArray_For_GMutableSpan(const CPPType &type, const int64_t size)
+      : GVMutableArray(type, size), element_size_(type.size())
+  {
+  }
+
  protected:
+  void set_span_start(void *data)
+  {
+    data_ = data;
+  }
+
   void get_impl(const int64_t index, void *r_value) const override;
   void get_to_uninitialized_impl(const int64_t index, void *r_value) const override;
 
@@ -545,6 +556,63 @@ class GVArray_As_GSpan final : public GVArray_For_GSpan {
   }
 };
 
+class GVMutableArray_As_GMutableSpan final : public GVMutableArray_For_GMutableSpan {
+ private:
+  GVMutableArray &varray_;
+  void *owned_data_ = nullptr;
+  bool apply_has_been_called_ = false;
+  bool show_not_applied_warning_ = true;
+
+ public:
+  GVMutableArray_As_GMutableSpan(GVMutableArray &varray)
+      : GVMutableArray_For_GMutableSpan(varray.type(), varray.size()), varray_(varray)
+  {
+    if (varray_.is_span()) {
+      this->set_span_start(varray_.get_span().data());
+    }
+    else {
+      owned_data_ = MEM_mallocN_aligned(type_->size() * size_, type_->alignment(), __func__);
+      varray_.materialize_to_uninitialized(IndexRange(size_), owned_data_);
+      this->set_span_start(owned_data_);
+    }
+  }
+
+  ~GVMutableArray_As_GMutableSpan()
+  {
+    if (show_not_applied_warning_) {
+      if (!apply_has_been_called_) {
+        std::cout << "Warning: Call `apply()` to make sure that changes persist in all cases.\n";
+      }
+    }
+  }
+
+  void apply()
+  {
+    apply_has_been_called_ = true;
+    if (data_ != owned_data_) {
+      return;
+    }
+    for (int64_t i : IndexRange(size_)) {
+      varray_.set_by_copy(i, POINTER_OFFSET(owned_data_, element_size_ * i));
+    }
+  }
+
+  void disable_not_applied_warning()
+  {
+    show_not_applied_warning_ = false;
+  }
+
+  GMutableSpan as_span()
+  {
+    return this->get_span();
+  }
+
+  operator GMutableSpan()
+  {
+    return this->get_span();
+  }
+};
+
 template<typename T> class GVArray_For_OwnedVArray : public GVArray_For_VArray<T> {
  private:
   std::unique_ptr<VArray<T>> owned_varray_;