Merge branch 'master' into temp-copy-on-write

source/blender/blenkernel/BKE_geometry_set.hh

@@ -23,13 +23,13 @@
 #include <atomic>
 #include <iostream>
 
+#include "BLI_copy_on_write.h"
 #include "BLI_float3.hh"
 #include "BLI_float4x4.hh"
 #include "BLI_function_ref.hh"
 #include "BLI_hash.hh"
 #include "BLI_map.hh"
 #include "BLI_set.hh"
-#include "BLI_user_counter.hh"
 #include "BLI_vector_set.hh"
 
 #include "BKE_anonymous_attribute.hh"
@@ -63,14 +63,13 @@ class GeometryComponent;
 
 /**
  * This is the base class for specialized geometry component types. A geometry component handles
- * a user count to allow avoiding duplication when it is wrapped with #UserCounter. It also handles
- * the attribute API, which generalizes storing and modifying generic information on a geometry.
+ * a user count to allow avoiding duplication when it is wrapped with #bCopyOnWrite. It also
+ * handles the attribute API, which generalizes storing and modifying generic information on a
+ * geometry.
  */
 class GeometryComponent {
  private:
-  /* The reference count has two purposes. When it becomes zero, the component is freed. When it is
-   * larger than one, the component becomes immutable. */
-  mutable std::atomic<int> users_ = 1;
+  blender::bCopyOnWrite cow_;
   GeometryComponentType type_;
 
  public:
@@ -81,14 +80,22 @@ class GeometryComponent {
   /* The returned component should be of the same type as the type this is called on. */
   virtual GeometryComponent *copy() const = 0;
 
+  const blender::bCopyOnWrite &cow() const
+  {
+    return cow_;
+  }
+
+  void cow_delete_self() const
+  {
+    delete this;
+  }
+
   /* Direct data is everything except for instances of objects/collections.
    * If this returns true, the geometry set can be cached and is still valid after e.g. modifier
    * evaluation ends. Instances can only be valid as long as the data they instance is valid. */
   virtual bool owns_direct_data() const = 0;
   virtual void ensure_owns_direct_data() = 0;
 
-  void user_add() const;
-  void user_remove() const;
   bool is_mutable() const;
 
   GeometryComponentType type() const;
@@ -310,7 +317,7 @@ inline constexpr bool is_geometry_component_v = std::is_base_of_v<GeometryCompon
  */
 struct GeometrySet {
  private:
-  using GeometryComponentPtr = blender::UserCounter<class GeometryComponent>;
+  using GeometryComponentPtr = blender::COWUser<class GeometryComponent>;
   /* Indexed by #GeometryComponentType. */
   std::array<GeometryComponentPtr, GEO_COMPONENT_TYPE_ENUM_SIZE> components_;
 

source/blender/blenkernel/intern/geometry_set.cc

@@ -69,24 +69,9 @@ GeometryComponent *GeometryComponent::create(GeometryComponentType component_typ
   return nullptr;
 }
 
-void GeometryComponent::user_add() const
-{
-  users_.fetch_add(1);
-}
-
-void GeometryComponent::user_remove() const
-{
-  const int new_users = users_.fetch_sub(1) - 1;
-  if (new_users == 0) {
-    delete this;
-  }
-}
-
 bool GeometryComponent::is_mutable() const
 {
-  /* If the item is shared, it is read-only. */
-  /* The user count can be 0, when this is called from the destructor. */
-  return users_ <= 1;
+  return cow_.is_mutable();
 }
 
 GeometryComponentType GeometryComponent::type() const
@@ -168,7 +153,7 @@ void GeometrySet::keep_only(const blender::Span<GeometryComponentType> component
 void GeometrySet::add(const GeometryComponent &component)
 {
   BLI_assert(!components_[component.type()]);
-  component.user_add();
+  component.cow().user_add();
   components_[component.type()] = const_cast<GeometryComponent *>(&component);
 }
 

source/blender/blenlib/BLI_copy_on_write.h

@@ -20,41 +20,95 @@
  * \ingroup bli
  */
 
-#include <atomic>
+#include "BLI_assert.h"
+#include "BLI_compiler_attrs.h"
+#include "BLI_utility_mixins.hh"
+
+#include "DNA_copy_on_write.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bCopyOnWrite *BLI_cow_new(int user_count);
+void BLI_cow_free(const bCopyOnWrite *cow);
+
+void BLI_cow_init(const bCopyOnWrite *cow);
+
+bool BLI_cow_is_shared(const bCopyOnWrite *cow);
+bool BLI_cow_is_mutable(const bCopyOnWrite *cow);
+
+void BLI_cow_user_add(const bCopyOnWrite *cow);
+bool BLI_cow_user_remove(const bCopyOnWrite *cow) ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#ifdef __cplusplus
 
 namespace blender {
 
-/**
- * A simple automatic reference counter. It is similar to std::shared_ptr, but expects that the
- * reference count is inside the object.
- */
-template<typename T> class UserCounter {
+class bCopyOnWrite : public ::bCopyOnWrite, private NonCopyable, NonMovable {
+ public:
+  bCopyOnWrite()
+  {
+    BLI_cow_init(this);
+  }
+
+  ~bCopyOnWrite()
+  {
+    BLI_assert(this->is_mutable());
+  }
+
+  bool is_shared() const
+  {
+    return BLI_cow_is_shared(this);
+  }
+
+  bool is_mutable() const
+  {
+    return BLI_cow_is_mutable(this);
+  }
+
+  void user_add() const
+  {
+    BLI_cow_user_add(this);
+  }
+
+  bool user_remove() const ATTR_WARN_UNUSED_RESULT
+  {
+    return BLI_cow_user_remove(this);
+  }
+};
+
+template<typename T> class COWUser {
  private:
   T *data_ = nullptr;
 
  public:
-  UserCounter() = default;
+  COWUser() = default;
 
-  UserCounter(T *data) : data_(data)
+  COWUser(T *data) : data_(data)
   {
   }
 
-  UserCounter(const UserCounter &other) : data_(other.data_)
+  COWUser(const COWUser &other) : data_(other.data_)
   {
     this->user_add(data_);
   }
 
-  UserCounter(UserCounter &&other) : data_(other.data_)
+  COWUser(COWUser &&other) : data_(other.data_)
   {
     other.data_ = nullptr;
   }
 
-  ~UserCounter()
+  ~COWUser()
   {
     this->user_remove(data_);
   }
 
-  UserCounter &operator=(const UserCounter &other)
+  COWUser &operator=(const COWUser &other)
   {
     if (this == &other) {
       return *this;
@@ -66,7 +120,7 @@ template<typename T> class UserCounter {
     return *this;
   }
 
-  UserCounter &operator=(UserCounter &&other)
+  COWUser &operator=(COWUser &&other)
   {
     if (this == &other) {
       return *this;
@@ -140,31 +194,29 @@ template<typename T> class UserCounter {
     return get_default_hash(data_);
   }
 
-  friend bool operator==(const UserCounter &a, const UserCounter &b)
+  friend bool operator==(const COWUser &a, const COWUser &b)
   {
     return a.data_ == b.data_;
   }
 
-  friend std::ostream &operator<<(std::ostream &stream, const UserCounter &value)
-  {
-    stream << value.data_;
-    return stream;
-  }
-
  private:
   static void user_add(T *data)
   {
     if (data != nullptr) {
-      data->user_add();
+      data->cow().user_add();
     }
   }
 
   static void user_remove(T *data)
   {
     if (data != nullptr) {
-      data->user_remove();
+      if (data->cow().user_remove()) {
+        data->cow_delete_self();
+      }
     }
   }
 };
 
 }  // namespace blender
+
+#endif

source/blender/blenlib/CMakeLists.txt

@@ -68,6 +68,7 @@ set(SRC
   intern/boxpack_2d.c
   intern/buffer.c
   intern/convexhull_2d.c
+  intern/copy_on_write.cc
   intern/delaunay_2d.cc
   intern/dot_export.cc
   intern/dynlib.c
@@ -187,6 +188,7 @@ set(SRC
   BLI_compiler_typecheck.h
   BLI_console.h
   BLI_convexhull_2d.h
+  BLI_copy_on_write.h
   BLI_delaunay_2d.h
   BLI_dial_2d.h
   BLI_disjoint_set.hh
@@ -310,7 +312,6 @@ set(SRC
   BLI_timecode.h
   BLI_timeit.hh
   BLI_timer.h
-  BLI_user_counter.hh
   BLI_utildefines.h
   BLI_utildefines_iter.h
   BLI_utildefines_stack.h

source/blender/blenlib/intern/copy_on_write.cc

@@ -0,0 +1,73 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup bli
+ */
+
+#include "atomic_ops.h"
+
+#include "BLI_assert.h"
+#include "BLI_copy_on_write.h"
+
+#include "MEM_guardedalloc.h"
+
+static int &get_counter(const bCopyOnWrite *cow)
+{
+  BLI_assert(cow != nullptr);
+  return *const_cast<int *>(&cow->user_count);
+}
+
+bCopyOnWrite *BLI_cow_new(int user_count)
+{
+  bCopyOnWrite *cow = MEM_cnew<bCopyOnWrite>(__func__);
+  cow->user_count = user_count;
+  return cow;
+}
+
+void BLI_cow_free(const bCopyOnWrite *cow)
+{
+  BLI_assert(cow->user_count == 0);
+  MEM_freeN(const_cast<bCopyOnWrite *>(cow));
+}
+
+void BLI_cow_init(const bCopyOnWrite *cow)
+{
+  get_counter(cow) = 1;
+}
+
+bool BLI_cow_is_mutable(const bCopyOnWrite *cow)
+{
+  return !BLI_cow_is_shared(cow);
+}
+
+bool BLI_cow_is_shared(const bCopyOnWrite *cow)
+{
+  return cow->user_count >= 2;
+}
+
+void BLI_cow_user_add(const bCopyOnWrite *cow)
+{
+  atomic_fetch_and_add_int32(&get_counter(cow), 1);
+}
+
+bool BLI_cow_user_remove(const bCopyOnWrite *cow)
+{
+  const int new_user_count = atomic_sub_and_fetch_int32(&get_counter(cow), 1);
+  BLI_assert(new_user_count >= 0);
+  const bool has_no_user_anymore = new_user_count == 0;
+  return has_no_user_anymore;
+}

source/blender/geometry/intern/realize_instances.cc

@@ -191,7 +191,7 @@ struct GatherTasks {
 
   /* Volumes only have very simple support currently. Only the first found volume is put into the
    * output. */
-  UserCounter<VolumeComponent> first_volume;
+  COWUser<VolumeComponent> first_volume;
 };
 
 /** Current offsets while during the gather operation. */
@@ -480,7 +480,7 @@ static void gather_realize_tasks_recursive(GatherTasksInfo &gather_info,
       case GEO_COMPONENT_TYPE_VOLUME: {
         const VolumeComponent *volume_component = static_cast<const VolumeComponent *>(component);
         if (!gather_info.r_tasks.first_volume) {
-          volume_component->user_add();
+          volume_component->cow().user_add();
           gather_info.r_tasks.first_volume = const_cast<VolumeComponent *>(volume_component);
         }
         break;

source/blender/makesdna/DNA_copy_on_write.h

@@ -0,0 +1,25 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup DNA
+ */
+
+#pragma once
+
+typedef struct bCopyOnWrite {
+  int user_count;
+} bCopyOnWrite;

source/blender/makesdna/intern/makesdna.c

@@ -141,6 +141,7 @@ static const char *includefiles[] = {
     "DNA_pointcache_types.h",
     "DNA_uuid_types.h",
     "DNA_asset_types.h",
+    "DNA_copy_on_write.h",
 
     /* see comment above before editing! */
 
@@ -1624,6 +1625,7 @@ int main(int argc, char **argv)
 #include "DNA_collection_types.h"
 #include "DNA_color_types.h"
 #include "DNA_constraint_types.h"
+#include "DNA_copy_on_write.h"
 #include "DNA_curve_types.h"
 #include "DNA_curveprofile_types.h"
 #include "DNA_customdata_types.h"