Clean up instance bindings for engine singletons to prevent crash

2 files changed, 19 insertions, 0 deletions

diff --git a/include/godot_cpp/core/class_db.hpp b/include/godot_cpp/core/class_db.hpp
index ca5a326..8ef7f8e 100644
--- a/include/godot_cpp/core/class_db.hpp
+++ b/include/godot_cpp/core/class_db.hpp
@@ -45,6 +45,7 @@
 #include <godot_cpp/variant/callable_method_pointer.hpp>
 
 #include <list>
+#include <mutex>
 #include <set>
 #include <string>
 #include <unordered_map>
@@ -104,6 +105,8 @@ private:
 	static std::unordered_map<StringName, const GDExtensionInstanceBindingCallbacks *> instance_binding_callbacks;
 	// Used to remember the custom class registration order.
 	static std::vector<StringName> class_register_order;
+	static std::unordered_map<StringName, Object *> engine_singletons;
+	static std::mutex engine_singletons_mutex;
 
 	static MethodBind *bind_methodfi(uint32_t p_flags, MethodBind *p_bind, const MethodDefinition &method_name, const void **p_defs, int p_defcount);
 	static void initialize_class(const ClassInfo &cl);
@@ -153,6 +156,21 @@ public:
 		instance_binding_callbacks[p_name] = p_callbacks;
 	}
 
+	static void _register_engine_singleton(const StringName &p_class_name, Object *p_singleton) {
+		std::lock_guard<std::mutex> lock(engine_singletons_mutex);
+		std::unordered_map<StringName, Object *>::const_iterator i = engine_singletons.find(p_class_name);
+		if (i != engine_singletons.end()) {
+			ERR_FAIL_COND((*i).second != p_singleton);
+			return;
+		}
+		engine_singletons[p_class_name] = p_singleton;
+	}
+
+	static void _unregister_engine_singleton(const StringName &p_class_name) {
+		std::lock_guard<std::mutex> lock(engine_singletons_mutex);
+		engine_singletons.erase(p_class_name);
+	}
+
 	template <typename N, typename M, typename... VarArgs>
 	static MethodBind *bind_method(N p_method_name, M p_method, VarArgs... p_args);
 
diff --git a/include/godot_cpp/godot.hpp b/include/godot_cpp/godot.hpp
index 95a0387..822363d 100644
--- a/include/godot_cpp/godot.hpp
+++ b/include/godot_cpp/godot.hpp
@@ -162,6 +162,7 @@ extern "C" GDExtensionInterfaceObjectDestroy gdextension_interface_object_destro
 extern "C" GDExtensionInterfaceGlobalGetSingleton gdextension_interface_global_get_singleton;
 extern "C" GDExtensionInterfaceObjectGetInstanceBinding gdextension_interface_object_get_instance_binding;
 extern "C" GDExtensionInterfaceObjectSetInstanceBinding gdextension_interface_object_set_instance_binding;
+extern "C" GDExtensionInterfaceObjectFreeInstanceBinding gdextension_interface_object_free_instance_binding;
 extern "C" GDExtensionInterfaceObjectSetInstance gdextension_interface_object_set_instance;
 extern "C" GDExtensionInterfaceObjectGetClassName gdextension_interface_object_get_class_name;
 extern "C" GDExtensionInterfaceObjectCastTo gdextension_interface_object_cast_to;