🐛 Fix virtual methods to not use template meta programming

Implementation to test godotengine/godot#80671

Fixes #11

godot-headers/godot/gdextension_interface.h

@@ -266,6 +266,8 @@ typedef void (*GDExtensionClassCallVirtual)(GDExtensionClassInstancePtr p_instan
 typedef GDExtensionObjectPtr (*GDExtensionClassCreateInstance)(void *p_userdata);
 typedef void (*GDExtensionClassFreeInstance)(void *p_userdata, GDExtensionClassInstancePtr p_instance);
 typedef GDExtensionClassCallVirtual (*GDExtensionClassGetVirtual)(void *p_userdata, GDExtensionConstStringNamePtr p_name);
+typedef void *(*GDExtensionClassGetVirtuaCallData)(void *p_userdata, GDExtensionConstStringNamePtr p_name);
+typedef void (*GDExtensionClassCallVirtualWithData)(GDExtensionClassInstancePtr p_instance, GDExtensionConstStringNamePtr p_name, void *p_userdata, const GDExtensionConstTypePtr *p_args, GDExtensionTypePtr r_ret);
 
 typedef struct {
 	GDExtensionBool is_virtual;
@@ -283,6 +285,12 @@ typedef struct {
 	GDExtensionClassCreateInstance create_instance_func; // (Default) constructor; mandatory. If the class is not instantiable, consider making it virtual or abstract.
 	GDExtensionClassFreeInstance free_instance_func; // Destructor; mandatory.
 	GDExtensionClassGetVirtual get_virtual_func; // Queries a virtual function by name and returns a callback to invoke the requested virtual function.
+	// Can be used instead of `get_virtual_func`. Returns user data (non-null) that will be passed back when calling `call_virtual_func`.
+	// Returning `null` from this function signals to Godot that the virutal function is not overriden.
+	// Data provided to this function must live until the GDExtensionInstance is freed, but should be deleted when `free_instance_func` is called.
+	GDExtensionClassGetVirtuaCallData get_virtual_call_data_func;
+	// Used to call virtual functions when `get_virtual_call_data_func` is not null.
+	GDExtensionClassCallVirtualWithData call_virtual_func;
 	GDExtensionClassGetRID get_rid_func;
 	void *class_userdata; // Per-class user data, later accessible in instance bindings.
 } GDExtensionClassCreationInfo;
@@ -1526,6 +1534,25 @@ typedef void (*GDExtensionInterfaceStringOperatorPlusEqWcstr)(GDExtensionStringP
  */
 typedef void (*GDExtensionInterfaceStringOperatorPlusEqC32str)(GDExtensionStringPtr p_self, const char32_t *p_b);
 
+/**
+ * @name string_resize
+ * @since 4.2
+ *
+ * Resizes the underlying string data to the given number of characters.
+ *
+ * Space needs to be allocated for the null terminating character ('\0') which
+ * also must be added manually, in order for all string functions to work correctly.
+ *
+ * Warning: This is an error-prone operation - only use it if there's no other
+ * efficient way to accomplish your goal.
+ *
+ * @param p_self A pointer to the String.
+ * @param p_resize The new length for the String.
+ *
+ * @return Error code signifying if the operation successful.
+ */
+typedef GDExtensionInt (*GDExtensionInterfaceStringResize)(GDExtensionStringPtr p_self, GDExtensionInt p_resize);
+
 /* INTERFACE: XMLParser Utilities */
 
 /**
@@ -2110,13 +2137,13 @@ typedef GDExtensionScriptInstancePtr (*GDExtensionInterfaceScriptInstanceCreate)
 /**
  * @name object_get_script_instance
  * @since 4.2
- * 
+ *
  * Get the script instance data attached to this object.
- * 
- * @param p_object A pointer to the Object
- * @param p_language A pointer to the language expected for this script instance
- * 
- * @return A GDExtensionScriptInstanceDataPtr that was attached to this object as part of script_instance_create
+ *
+ * @param p_object A pointer to the Object.
+ * @param p_language A pointer to the language expected for this script instance.
+ *
+ * @return A GDExtensionScriptInstanceDataPtr that was attached to this object as part of script_instance_create.
  */
 typedef GDExtensionScriptInstanceDataPtr (*GDExtensionInterfaceObjectGetScriptInstance)(GDExtensionConstObjectPtr p_object, GDExtensionObjectPtr p_language);
 
@@ -2224,6 +2251,23 @@ typedef void (*GDExtensionInterfaceClassdbRegisterExtensionClassIntegerConstant)
  */
 typedef void (*GDExtensionInterfaceClassdbRegisterExtensionClassProperty)(GDExtensionClassLibraryPtr p_library, GDExtensionConstStringNamePtr p_class_name, const GDExtensionPropertyInfo *p_info, GDExtensionConstStringNamePtr p_setter, GDExtensionConstStringNamePtr p_getter);
 
+/**
+ * @name classdb_register_extension_class_property_indexed
+ * @since 4.2
+ *
+ * Registers an indexed property on an extension class in the ClassDB.
+ *
+ * Provided struct can be safely freed once the function returns.
+ *
+ * @param p_library A pointer the library received by the GDExtension's entry point function.
+ * @param p_class_name A pointer to a StringName with the class name.
+ * @param p_info A pointer to a GDExtensionPropertyInfo struct.
+ * @param p_setter A pointer to a StringName with the name of the setter method.
+ * @param p_getter A pointer to a StringName with the name of the getter method.
+ * @param p_index The index to pass as the first argument to the getter and setter methods.
+ */
+typedef void (*GDExtensionInterfaceClassdbRegisterExtensionClassPropertyIndexed)(GDExtensionClassLibraryPtr p_library, GDExtensionConstStringNamePtr p_class_name, const GDExtensionPropertyInfo *p_info, GDExtensionConstStringNamePtr p_setter, GDExtensionConstStringNamePtr p_getter, GDExtensionInt p_index);
+
 /**
  * @name classdb_register_extension_class_property_group
  * @since 4.1

src/cpp/dart_bindings.cpp

@@ -11,7 +11,6 @@
 #include <godot/gdextension_interface.h>
 
 #include "dart_script_instance.h"
-#include "dart_vtable_wrapper.h"
 #include "gde_dart_converters.h"
 #include "gde_wrapper.h"
 #include "godot_string_wrappers.h"
@@ -144,8 +143,6 @@ GodotDartBindings::~GodotDartBindings() {
 }
 
 bool GodotDartBindings::initialize(const char *script_path, const char *package_config) {
-  dart_vtable_wrapper::init_virtual_thunks();
-
   DartDllConfig config;
   if (GDEWrapper::instance()->is_editor_hint()) {
     config.service_port = 6222;
@@ -653,22 +650,23 @@ void GodotDartBindings::class_free_instance(void *p_userdata, GDExtensionClassIn
   });
 }
 
-GDExtensionClassCallVirtual GodotDartBindings::get_virtual_func(void *p_userdata,
-                                                                GDExtensionConstStringNamePtr p_name) {
+void *GodotDartBindings::get_virtual_call_data(void *p_userdata, GDExtensionConstStringNamePtr p_name) {
   GodotDartBindings *bindings = GodotDartBindings::instance();
   if (!bindings) {
     // oooff
     return nullptr;
   }
 
-  GDExtensionClassCallVirtual func = nullptr;
+  void *user_data = nullptr;
   bindings->execute_on_dart_thread([&]() {
     DartBlockScope scope;
 
     Dart_Handle type = Dart_HandleFromPersistent(reinterpret_cast<Dart_PersistentHandle>(p_userdata));
 
-    DART_CHECK(typeInfo, Dart_GetField(type, Dart_NewStringFromCString("sTypeInfo")), "Error finding sTypeInfo on Type");
-    DART_CHECK(vtable, Dart_GetField(typeInfo, Dart_NewStringFromCString("vTable")), "Error finding vTable from TypeInfo");
+    DART_CHECK(typeInfo, Dart_GetField(type, Dart_NewStringFromCString("sTypeInfo")),
+               "Error finding sTypeInfo on Type");
+    DART_CHECK(vtable, Dart_GetField(typeInfo, Dart_NewStringFromCString("vTable")),
+               "Error finding vTable from TypeInfo");
     if (Dart_IsNull(vtable)) {
       return;
     }
@@ -687,10 +685,27 @@ GDExtensionClassCallVirtual GodotDartBindings::get_virtual_func(void *p_userdata
     uint64_t address = 0;
     Dart_IntegerToUint64(dart_address, &address);
 
-    func = dart_vtable_wrapper::get_wrapped_virtual(reinterpret_cast<GDExtensionClassCallVirtual>(address));
+    user_data = (void *)address;
   });
 
-  return func;
+  return user_data;
+}
+
+void GodotDartBindings::call_virtual_func(void* p_instance, GDExtensionConstStringNamePtr p_name,
+                                           void *p_userdata, const GDExtensionConstTypePtr *p_args,
+                                           GDExtensionTypePtr r_ret) {
+  GodotDartBindings *bindings = GodotDartBindings::instance();
+  if (!bindings) {
+    // oooff
+    return;
+  }
+
+  bindings->execute_on_dart_thread([&]() {
+    DartBlockScope scope;
+
+    GDExtensionClassCallVirtual dart_call = (GDExtensionClassCallVirtual)p_userdata;
+    dart_call(p_instance, p_args, r_ret);
+  });
 }
 
 /* Static Functions From Dart */
@@ -737,7 +752,9 @@ void bind_class(Dart_NativeArguments args) {
   info.class_userdata = (void *)Dart_NewPersistentHandle(type_arg);
   info.create_instance_func = GodotDartBindings::class_create_instance;
   info.free_instance_func = GodotDartBindings::class_free_instance;
-  info.get_virtual_func = GodotDartBindings::get_virtual_func;
+  //info.get_virtual_func = GodotDartBindings::get_virtual_func;
+  info.get_virtual_call_data_func = GodotDartBindings::get_virtual_call_data;
+  info.call_virtual_func = GodotDartBindings::call_virtual_func;
 
   gde_classdb_register_extension_class(GDEWrapper::instance()->get_library_ptr(), sn_name, sn_parent, &info);
 }

src/cpp/dart_bindings.h

@@ -65,7 +65,9 @@ class GodotDartBindings {
 
   static GDExtensionObjectPtr class_create_instance(void *p_userdata);
   static void class_free_instance(void *p_userdata, GDExtensionClassInstancePtr p_instance);
-  static GDExtensionClassCallVirtual get_virtual_func(void *p_userdata, GDExtensionConstStringNamePtr p_name);
+  static void *get_virtual_call_data(void *p_userdata, GDExtensionConstStringNamePtr p_name);
+  static void call_virtual_func(void* p_instance, GDExtensionConstStringNamePtr p_name,
+                                void *p_userdata, const GDExtensionConstTypePtr *p_args, GDExtensionTypePtr r_ret);
 
 private:
   static void bind_call(void *method_userdata, GDExtensionClassInstancePtr instance,

src/cpp/dart_script_instance.cpp

@@ -284,13 +284,16 @@ void DartScriptInstance::call(const GDStringName *p_method, const GDExtensionCon
   if (gde == nullptr) {
     return;
   }
+
   // TODO: Figure out wth placeholders do
   if (_is_placeholder) {
     // Placeholders always return CALL_ERROR_INVALID_METHOD
     r_error->error = GDEXTENSION_CALL_ERROR_INVALID_METHOD; 
     return;
   }
 
+  Dart_Handle *dart_args = nullptr;
+
   gde->execute_on_dart_thread([&] {
     DartBlockScope scope;
 
@@ -317,7 +320,6 @@ void DartScriptInstance::call(const GDStringName *p_method, const GDExtensionCon
     intptr_t arg_count = 0;
     Dart_ListLength(args_list, &arg_count);
 
-    Dart_Handle *dart_args = nullptr;
     if (arg_count != 0) {
       dart_args = new Dart_Handle[arg_count];
       Dart_Handle args_address = Dart_NewInteger(reinterpret_cast<intptr_t>(p_args));
@@ -367,13 +369,13 @@ void DartScriptInstance::call(const GDStringName *p_method, const GDExtensionCon
         gde_variant_new_copy(r_return, reinterpret_cast<GDExtensionConstVariantPtr>(variantDataPtr));
       }
     }
-
-    // TODO - these leak on error
-    if (dart_args != nullptr) {
-      delete[] dart_args;
-    }
   });
-  // TODO
+
+  if (dart_args != nullptr) {
+    delete[] dart_args;
+  }
+
+  // TODO: How do we throw exceptions in Godot?
   r_error->error = GDEXTENSION_CALL_OK;
 }
 

src/cpp/godot_dart.cpp

@@ -99,15 +99,4 @@ void GDE_EXPORT godot_dart_init(GDExtensionInterfaceGetProcAddress p_get_proc_ad
   r_initialization->minimum_initialization_level = GDEXTENSION_INITIALIZATION_SCENE;
 }
 
-//GDExtensionBool GDE_EXPORT godot_dart_init(const GDExtensionInterface *p_interface,
-//                                           GDExtensionClassLibraryPtr p_library,
-//                                           GDExtensionInitialization *r_initialization) {
-//  GDEWrapper::create_instance(p_interface, p_library);
-//
-//  r_initialization->initialize = initialize_level;
-//  r_initialization->deinitialize = deinitialize_level;
-//  r_initialization->minimum_initialization_level = GDEXTENSION_INITIALIZATION_SCENE;
-//
-//  return true;
-//}
 }

src/cpp/godot_dart.vcxproj

@@ -21,7 +21,6 @@
   <ItemGroup>
     <ClCompile Include="dart_bindings.cpp" />
     <ClCompile Include="dart_script_instance.cpp" />
-    <ClCompile Include="dart_vtable_wrapper.cpp" />
     <ClCompile Include="gde_c_interface.cpp" />
     <ClCompile Include="gde_dart_converters.cpp" />
     <ClCompile Include="godot_dart.cpp" />
@@ -31,7 +30,6 @@
   <ItemGroup>
     <ClInclude Include="dart_bindings.h" />
     <ClInclude Include="dart_script_instance.h" />
-    <ClInclude Include="dart_vtable_wrapper.h" />
     <ClInclude Include="gde_c_interface.h" />
     <ClInclude Include="gde_dart_converters.h" />
     <ClInclude Include="gde_wrapper.h" />

src/cpp/godot_dart.vcxproj.filters

@@ -4,7 +4,6 @@
     <ClCompile Include="godot_dart.cpp" />
     <ClCompile Include="dart_bindings.cpp" />
     <ClCompile Include="gde_wrapper..cpp" />
-    <ClCompile Include="dart_vtable_wrapper.cpp" />
     <ClCompile Include="godot_string_wrappers.cpp" />
     <ClCompile Include="dart_script_instance.cpp" />
     <ClCompile Include="gde_dart_converters.cpp" />
@@ -13,7 +12,6 @@
   <ItemGroup>
     <ClInclude Include="dart_bindings.h" />
     <ClInclude Include="gde_wrapper.h" />
-    <ClInclude Include="dart_vtable_wrapper.h" />
     <ClInclude Include="godot_string_wrappers.h" />
     <ClInclude Include="dart_script_instance.h" />
     <ClInclude Include="gde_dart_converters.h" />

src/dart/godot_dart_build/.dart_tool/package_config.json

@@ -242,7 +242,7 @@
       "languageVersion": "2.18"
     }
   ],
-  "generated": "2023-07-22T01:31:46.664742Z",
+  "generated": "2023-08-16T01:22:04.221907Z",
   "generator": "pub",
-  "generatorVersion": "3.0.3"
+  "generatorVersion": "3.0.6"
 }

src/dart/godot_dart_build/pubspec.yaml

@@ -1,6 +1,7 @@
 name: godot_dart_build
 description: build_runner interface for simplifying binding to Godot
 version: 1.0.0
+publish_to: none
 
 environment:
   sdk: '>=2.18.2 <3.0.0'