Add layer menu service boundary

src/app_core/document_layer.h

@@ -78,6 +78,16 @@ struct DocumentLayerMenuPlan {
     int to_index = 0;
 };
 
+class DocumentLayerMenuServices {
+public:
+    virtual ~DocumentLayerMenuServices() = default;
+
+    virtual void clear_current_layer() = 0;
+    virtual void show_rename_dialog() = 0;
+    virtual void merge_with_lower_layer(int from_index, int to_index) = 0;
+    virtual void show_merge_animated_not_supported() = 0;
+};
+
 [[nodiscard]] inline pp::foundation::Status validate_layer_index(
     int layer_count,
     int index) noexcept
@@ -410,4 +420,29 @@ struct DocumentLayerMenuPlan {
     return pp::foundation::Result<DocumentLayerMenuPlan>::success(std::move(plan));
 }
 
+[[nodiscard]] inline pp::foundation::Status execute_document_layer_menu_plan(
+    const DocumentLayerMenuPlan& plan,
+    DocumentLayerMenuServices& services)
+{
+    switch (plan.action) {
+    case DocumentLayerMenuAction::clear_current_layer:
+        services.clear_current_layer();
+        return pp::foundation::Status::success();
+    case DocumentLayerMenuAction::show_rename_dialog:
+        services.show_rename_dialog();
+        return pp::foundation::Status::success();
+    case DocumentLayerMenuAction::merge_with_lower_layer:
+        services.merge_with_lower_layer(plan.from_index, plan.to_index);
+        return pp::foundation::Status::success();
+    case DocumentLayerMenuAction::show_merge_animated_not_supported:
+        services.show_merge_animated_not_supported();
+        return pp::foundation::Status::success();
+    case DocumentLayerMenuAction::no_op_select_layer:
+    case DocumentLayerMenuAction::no_op_select_upper_layer:
+        return pp::foundation::Status::success();
+    }
+
+    return pp::foundation::Status::invalid_argument("unknown document layer menu action");
+}
+
 }