Geometry Nodes: improve geometry nodes evaluator internal api

This is a first step towards T87620.
It should not have any functional changes.

Goals of this refactor:
* Move the evaluator out of `MOD_nodes.cc`. That makes it easier to
  improve it in isolation.
* Extract core input/out parameter management out of `GeoNodeExecParams`.
  Managing this is the responsibility of the evaluator. This separation of
  concerns will be useful once we have lazy evaluation of certain inputs/outputs.

Differential Revision: https://developer.blender.org/D11085

3 files changed, 16 insertions, 1 deletions

diff --git a/source/blender/functions/FN_cpp_type.hh b/source/blender/functions/FN_cpp_type.hh
index 54ea0103fe5..cd1597a742c 100644
--- a/source/blender/functions/FN_cpp_type.hh
+++ b/source/blender/functions/FN_cpp_type.hh
@@ -666,7 +666,7 @@ class CPPType : NonCopyable, NonMovable {
 
   template<typename T> bool is() const
   {
-    return this == &CPPType::get<T>();
+    return this == &CPPType::get<std::decay_t<T>>();
   }
 };
 
diff --git a/source/blender/functions/FN_generic_pointer.hh b/source/blender/functions/FN_generic_pointer.hh
index 2bd66daa7fe..f88ff09f916 100644
--- a/source/blender/functions/FN_generic_pointer.hh
+++ b/source/blender/functions/FN_generic_pointer.hh
@@ -66,6 +66,16 @@ class GMutablePointer {
     return type_ != nullptr && type_->is<T>();
   }
 
+  template<typename T> T relocate_out()
+  {
+    BLI_assert(this->is_type<T>());
+    T value;
+    type_->relocate_to_initialized(data_, &value);
+    data_ = nullptr;
+    type_ = nullptr;
+    return value;
+  }
+
   void destruct()
   {
     BLI_assert(data_ != nullptr);
diff --git a/source/blender/functions/FN_generic_value_map.hh b/source/blender/functions/FN_generic_value_map.hh
index 68cb945f1af..4e7fe298874 100644
--- a/source/blender/functions/FN_generic_value_map.hh
+++ b/source/blender/functions/FN_generic_value_map.hh
@@ -93,6 +93,11 @@ template<typename Key> class GValueMap {
     return values_.pop_as(key);
   }
 
+  template<typename ForwardKey> GPointer lookup(const ForwardKey &key) const
+  {
+    return values_.lookup_as(key);
+  }
+
   /* Remove the value for the given name from the container and remove it. */
   template<typename T, typename ForwardKey> T extract(const ForwardKey &key)
   {