fix(LiveView): Don't render values that are too large

This pertains to very large structs, because ExportTextItem is too slow, causing FPS to drop to less than 1.

Note that the value '500' is arbitrary, please feel free to change this to a more appropriate number if you can find one.

Author: UE4SS

UE4SS/src/GUI/LiveView.cpp

@@ -35,6 +35,7 @@
 #include <Unreal/Property/FObjectProperty.hpp>
 #include <Unreal/Property/FEnumProperty.hpp>
 #include <Unreal/Property/NumericPropertyTypes.hpp>
+#include <Unreal/Property/FMapProperty.hpp>
 #include <Unreal/UClass.hpp>
 #include <Unreal/UEnum.hpp>
 #include <Unreal/UFunction.hpp>
@@ -101,6 +102,7 @@ namespace RC::GUI
         void* container = nullptr;
         UObject* obj = nullptr;
         LiveView::ContainerType container_type = LiveView::ContainerType::Object;
+        bool editable = true;
     };
     static DeferredPropertyEditPopup s_deferred_property_edit_popup{};
 
@@ -2198,7 +2200,39 @@ namespace RC::GUI
         FString property_text{};
         auto property_name = to_string(property->GetName());
         auto container_ptr = property->ContainerPtrToValuePtr<void*>(container);
-        property->ExportTextItem(property_text, container_ptr, container_ptr, static_cast<UObject*>(container), NULL);
+        static constexpr int32 s_max_structure_size = 500;
+        auto as_struct_property = CastField<FStructProperty>(property);
+        static constexpr auto s_error_too_large = STR("Too large to display!");
+        bool editable = true;
+        if (auto as_map_property = CastField<FMapProperty>(property))
+        {
+            auto map = std::bit_cast<FScriptMap*>(container_ptr);
+            if (auto value_as_struct_property = CastField<FStructProperty>(as_map_property->GetValueProp());
+                value_as_struct_property && value_as_struct_property->GetStruct()->GetStructureSize() * map->Num() > s_max_structure_size)
+            {
+                editable = false;
+                property_text = FString{s_error_too_large};
+            }
+            else
+            {
+                property->ExportTextItem(property_text, container_ptr, container_ptr, static_cast<UObject*>(container), NULL);
+            }
+        }
+        else if (auto as_array_property = CastField<FArrayProperty>(property);
+                 as_array_property && as_array_property->GetSize() * std::bit_cast<FScriptArray*>(container_ptr)->Num() > s_max_structure_size)
+        {
+            editable = false;
+            property_text = FString{s_error_too_large};
+        }
+        else if (as_struct_property && as_struct_property->GetStruct()->GetStructureSize() > s_max_structure_size)
+        {
+            editable = false;
+            property_text = FString{s_error_too_large};
+        }
+        else
+        {
+            property->ExportTextItem(property_text, container_ptr, container_ptr, static_cast<UObject*>(container), NULL);
+        }
 
         bool open_edit_value_popup{};
 
@@ -2286,20 +2320,16 @@ namespace RC::GUI
                         container_type == ContainerType::Array ? fmt::format("").c_str() : fmt::format(" (0x{:X})", property_offset).c_str(),
                         property_name.c_str());
         }
-        if (auto struct_property = CastField<FStructProperty>(property); struct_property && struct_property->GetStruct()->GetFirstProperty())
+        if (as_struct_property && as_struct_property->GetStruct()->GetFirstProperty())
         {
             ImGui::SameLine();
             auto tree_node_id = fmt::format("{}{}", static_cast<void*>(container_ptr), property_name);
             if (ImGui_TreeNodeEx(fmt::format("{}", to_string(*property_text)).c_str(), tree_node_id.c_str(), ImGuiTreeNodeFlags_NoAutoOpenOnLog))
             {
                 render_property_value_context_menu(tree_node_id);
 
-                for (FProperty* inner_property : struct_property->GetStruct()->ForEachProperty())
+                for (FProperty* inner_property : as_struct_property->GetStruct()->ForEachProperty())
                 {
-                    FString struct_prop_text_item{};
-                    auto struct_prop_container_ptr = inner_property->ContainerPtrToValuePtr<void*>(container_ptr);
-                    inner_property->ExportTextItem(struct_prop_text_item, struct_prop_container_ptr, struct_prop_container_ptr, nullptr, NULL);
-
                     ImGui::Indent();
                     FProperty* last_struct_prop{};
                     next_item_to_render = render_property_value(inner_property,
@@ -2412,10 +2442,25 @@ namespace RC::GUI
 
         if (open_edit_value_popup)
         {
+            // Re-snapshot the value, because it may not be set due to it being too large of a type to export quickly.
+            // Why is this an empty string ? Wtf ?
+            // It seems it's not empty, but imgui isn't rendering the text properly for some reason, it's rendered as spaces.
+            // When you copy the text, it does copy the actual text, not spaces.
+            //FString snapshotted_property_text{};
+            //property->ExportTextItem(snapshotted_property_text, container_ptr, container_ptr, static_cast<UObject*>(container), NULL);
             // Defer the popup opening - store all necessary context
             s_deferred_property_edit_popup.pending = true;
             s_deferred_property_edit_popup.modal_name = edit_property_value_modal_name;
-            s_deferred_property_edit_popup.initial_value = to_string(*property_text);
+            if (!editable)
+            {
+                s_deferred_property_edit_popup.editable = false;
+                s_deferred_property_edit_popup.initial_value = "Too large to edit!";
+            }
+            else
+            {
+                s_deferred_property_edit_popup.editable = true;
+                s_deferred_property_edit_popup.initial_value = to_string(*property_text);
+            }
             s_deferred_property_edit_popup.property = property;
             s_deferred_property_edit_popup.container = container;
             s_deferred_property_edit_popup.obj = obj;
@@ -3397,6 +3442,10 @@ namespace RC::GUI
             ImGui::Text("The game could crash if the new value is invalid.");
             ImGui::Text("The game can override the new value immediately.");
             ImGui::PushItemWidth(-1.0f);
+            if (!s_deferred_property_edit_popup.editable)
+            {
+                ImGui::BeginDisabled();
+            }
             ImGui::InputText("##CurrentPropertyValue", &m_current_property_value_buffer);
             if (ImGui::Button("Apply"))
             {
@@ -3417,6 +3466,10 @@ namespace RC::GUI
                     s_deferred_property_edit_popup.property = nullptr; // Clear the deferred state
                 }
             }
+            if (!s_deferred_property_edit_popup.editable)
+            {
+                ImGui::EndDisabled();
+            }
 
             if (ImGui::BeginPopupModal("UnableToSetNewPropertyValueError",
                                        &m_modal_edit_property_value_error_unable_to_edit,
@@ -3435,6 +3488,7 @@ namespace RC::GUI
         if (!m_modal_edit_property_value_is_open)
         {
             s_deferred_property_edit_popup.property = nullptr;
+            s_deferred_property_edit_popup.editable = true;
         }
 
         // Handle deferred enum edit popup