Fix C# native instance bindings after recent re-write

This was needed after: 44691448911f1d29d4d79dbdd5553734761e57c4

5 files changed, 121 insertions, 123 deletions

diff --git a/modules/mono/csharp_script.cpp b/modules/mono/csharp_script.cpp
index 520262c0eb..5c5a4fc1ec 100644
--- a/modules/mono/csharp_script.cpp
+++ b/modules/mono/csharp_script.cpp
@@ -82,6 +82,12 @@ static bool _create_project_solution_if_needed() {
 
 CSharpLanguage *CSharpLanguage::singleton = nullptr;
 
+GDNativeInstanceBindingCallbacks CSharpLanguage::_instance_binding_callbacks = {
+	&_instance_binding_create_callback,
+	&_instance_binding_free_callback,
+	&_instance_binding_reference_callback
+};
+
 String CSharpLanguage::get_name() const {
 	return "C#";
 }
@@ -1444,46 +1450,46 @@ bool CSharpLanguage::setup_csharp_script_binding(CSharpScriptBinding &r_script_b
 	return true;
 }
 
-void *CSharpLanguage::alloc_instance_binding_data(Object *p_object) {
-	MutexLock lock(language_bind_mutex);
+Map<Object *, CSharpScriptBinding>::Element *CSharpLanguage::insert_script_binding(Object *p_object, const CSharpScriptBinding &p_script_binding) {
+	return script_bindings.insert(p_object, p_script_binding);
+}
+
+void *CSharpLanguage::_instance_binding_create_callback(void *, void *p_instance) {
+	CSharpLanguage *csharp_lang = CSharpLanguage::get_singleton();
 
-	Map<Object *, CSharpScriptBinding>::Element *match = script_bindings.find(p_object);
+	MutexLock lock(csharp_lang->language_bind_mutex);
+
+	Map<Object *, CSharpScriptBinding>::Element *match = csharp_lang->script_bindings.find((Object *)p_instance);
 	if (match) {
 		return (void *)match;
 	}
 
 	CSharpScriptBinding script_binding;
 
-	if (!setup_csharp_script_binding(script_binding, p_object)) {
-		return nullptr;
-	}
-
-	return (void *)insert_script_binding(p_object, script_binding);
+	return (void *)csharp_lang->insert_script_binding((Object *)p_instance, script_binding);
 }
 
-Map<Object *, CSharpScriptBinding>::Element *CSharpLanguage::insert_script_binding(Object *p_object, const CSharpScriptBinding &p_script_binding) {
-	return script_bindings.insert(p_object, p_script_binding);
-}
+void CSharpLanguage::_instance_binding_free_callback(void *, void *, void *p_binding) {
+	CSharpLanguage *csharp_lang = CSharpLanguage::get_singleton();
 
-void CSharpLanguage::free_instance_binding_data(void *p_data) {
 	if (GDMono::get_singleton() == nullptr) {
 #ifdef DEBUG_ENABLED
-		CRASH_COND(!script_bindings.is_empty());
+		CRASH_COND(!csharp_lang->script_bindings.is_empty());
 #endif
 		// Mono runtime finalized, all the gchandle bindings were already released
 		return;
 	}
 
-	if (finalizing) {
+	if (csharp_lang->finalizing) {
 		return; // inside CSharpLanguage::finish(), all the gchandle bindings are released there
 	}
 
 	GD_MONO_ASSERT_THREAD_ATTACHED;
 
 	{
-		MutexLock lock(language_bind_mutex);
+		MutexLock lock(csharp_lang->language_bind_mutex);
 
-		Map<Object *, CSharpScriptBinding>::Element *data = (Map<Object *, CSharpScriptBinding>::Element *)p_data;
+		Map<Object *, CSharpScriptBinding>::Element *data = (Map<Object *, CSharpScriptBinding>::Element *)p_binding;
 
 		CSharpScriptBinding &script_binding = data->value();
 
@@ -1497,92 +1503,110 @@ void CSharpLanguage::free_instance_binding_data(void *p_data) {
 			script_binding.gchandle.release();
 		}
 
-		script_bindings.erase(data);
+		csharp_lang->script_bindings.erase(data);
 	}
 }
 
-void CSharpLanguage::refcount_incremented_instance_binding(Object *p_object) {
-#if 0
-	RefCounted *rc_owner = Object::cast_to<RefCounted>(p_object);
+GDNativeBool CSharpLanguage::_instance_binding_reference_callback(void *p_token, void *p_binding, GDNativeBool p_reference) {
+	CRASH_COND(!p_binding);
+
+	CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)p_binding)->get();
+
+	RefCounted *rc_owner = Object::cast_to<RefCounted>(script_binding.owner);
 
 #ifdef DEBUG_ENABLED
 	CRASH_COND(!rc_owner);
-	CRASH_COND(!p_object->has_script_instance_binding(get_language_index()));
 #endif
 
-	void *data = p_object->get_script_instance_binding(get_language_index());
-	CRASH_COND(!data);
-
-	CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)data)->get();
 	MonoGCHandleData &gchandle = script_binding.gchandle;
 
+	int refcount = rc_owner->reference_get_count();
+
 	if (!script_binding.inited) {
-		return;
+		return refcount == 0;
 	}
 
-	if (rc_owner->reference_get_count() > 1 && gchandle.is_weak()) { // The managed side also holds a reference, hence 1 instead of 0
-		GD_MONO_SCOPE_THREAD_ATTACH;
+	if (p_reference) {
+		// Refcount incremented
+		if (refcount > 1 && gchandle.is_weak()) { // The managed side also holds a reference, hence 1 instead of 0
+			GD_MONO_SCOPE_THREAD_ATTACH;
 
-		// The reference count was increased after the managed side was the only one referencing our owner.
-		// This means the owner is being referenced again by the unmanaged side,
-		// so the owner must hold the managed side alive again to avoid it from being GCed.
+			// The reference count was increased after the managed side was the only one referencing our owner.
+			// This means the owner is being referenced again by the unmanaged side,
+			// so the owner must hold the managed side alive again to avoid it from being GCed.
+
+			MonoObject *target = gchandle.get_target();
+			if (!target) {
+				return false; // Called after the managed side was collected, so nothing to do here
+			}
 
-		MonoObject *target = gchandle.get_target();
-		if (!target) {
-			return; // Called after the managed side was collected, so nothing to do here
+			// Release the current weak handle and replace it with a strong handle.
+			MonoGCHandleData strong_gchandle = MonoGCHandleData::new_strong_handle(target);
+			gchandle.release();
+			gchandle = strong_gchandle;
 		}
 
-		// Release the current weak handle and replace it with a strong handle.
-		MonoGCHandleData strong_gchandle = MonoGCHandleData::new_strong_handle(target);
-		gchandle.release();
-		gchandle = strong_gchandle;
-	}
-#endif
-}
+		return false;
+	} else {
+		// Refcount decremented
+		if (refcount == 1 && !gchandle.is_released() && !gchandle.is_weak()) { // The managed side also holds a reference, hence 1 instead of 0
+			GD_MONO_SCOPE_THREAD_ATTACH;
 
-bool CSharpLanguage::refcount_decremented_instance_binding(Object *p_object) {
-#if 0
-	RefCounted *rc_owner = Object::cast_to<RefCounted>(p_object);
+			// If owner owner is no longer referenced by the unmanaged side,
+			// the managed instance takes responsibility of deleting the owner when GCed.
 
-#ifdef DEBUG_ENABLED
-	CRASH_COND(!rc_owner);
-	CRASH_COND(!p_object->has_script_instance_binding(get_language_index()));
-#endif
+			MonoObject *target = gchandle.get_target();
+			if (!target) {
+				return refcount == 0; // Called after the managed side was collected, so nothing to do here
+			}
 
-	void *data = p_object->get_script_instance_binding(get_language_index());
-	CRASH_COND(!data);
+			// Release the current strong handle and replace it with a weak handle.
+			MonoGCHandleData weak_gchandle = MonoGCHandleData::new_weak_handle(target);
+			gchandle.release();
+			gchandle = weak_gchandle;
 
-	CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)data)->get();
-	MonoGCHandleData &gchandle = script_binding.gchandle;
-
-	int refcount = rc_owner->reference_get_count();
+			return false;
+		}
 
-	if (!script_binding.inited) {
 		return refcount == 0;
 	}
+}
 
-	if (refcount == 1 && !gchandle.is_released() && !gchandle.is_weak()) { // The managed side also holds a reference, hence 1 instead of 0
-		GD_MONO_SCOPE_THREAD_ATTACH;
+void *CSharpLanguage::get_instance_binding(Object *p_object) {
+	void *binding = p_object->get_instance_binding(get_singleton(), &_instance_binding_callbacks);
 
-		// If owner owner is no longer referenced by the unmanaged side,
-		// the managed instance takes responsibility of deleting the owner when GCed.
+	// Initially this was in `_instance_binding_create_callback`. However, after the new instance
+	// binding re-write it was resulting in a deadlock in `_instance_binding_reference`, as
+	// `setup_csharp_script_binding` may call `reference()`. It was moved here outside to fix that.
 
-		MonoObject *target = gchandle.get_target();
-		if (!target) {
-			return refcount == 0; // Called after the managed side was collected, so nothing to do here
-		}
+	if (binding) {
+		CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)binding)->value();
 
-		// Release the current strong handle and replace it with a weak handle.
-		MonoGCHandleData weak_gchandle = MonoGCHandleData::new_weak_handle(target);
-		gchandle.release();
-		gchandle = weak_gchandle;
+		if (!script_binding.inited) {
+			MutexLock lock(CSharpLanguage::get_singleton()->get_language_bind_mutex());
 
-		return false;
+			if (!script_binding.inited) { // Another thread may have set it up
+				CSharpLanguage::get_singleton()->setup_csharp_script_binding(script_binding, p_object);
+			}
+		}
 	}
 
-	return refcount == 0;
+	return binding;
+}
+
+void *CSharpLanguage::get_existing_instance_binding(Object *p_object) {
+#ifdef DEBUG_ENABLED
+	CRASH_COND(p_object->has_instance_binding(p_object));
 #endif
-	return false;
+	return p_object->get_instance_binding(get_singleton(), &_instance_binding_callbacks);
+}
+
+void CSharpLanguage::set_instance_binding(Object *p_object, void *p_binding) {
+	p_object->set_instance_binding(get_singleton(), p_binding, &_instance_binding_callbacks);
+}
+
+bool CSharpLanguage::has_instance_binding(Object *p_object) {
+	return p_object->has_instance_binding(get_singleton());
 }
 
 CSharpInstance *CSharpInstance::create_for_managed_type(Object *p_owner, CSharpScript *p_script, const MonoGCHandleData &p_gchandle) {
@@ -2260,29 +2284,16 @@ CSharpInstance::~CSharpInstance() {
 		// Otherwise, the unsafe reference debug checks will incorrectly detect a bug.
 		bool die = _unreference_owner_unsafe();
 		CRASH_COND(die); // `owner_keep_alive` holds a reference, so it can't die
-#if 0
-		void *data = owner->get_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index());
-
 
+		void *data = CSharpLanguage::get_instance_binding(owner);
 		CRASH_COND(data == nullptr);
-
 		CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)data)->get();
-
-		if (!script_binding.inited) {
-			MutexLock lock(CSharpLanguage::get_singleton()->get_language_bind_mutex());
-
-			if (!script_binding.inited) { // Other thread may have set it up
-				// Already had a binding that needs to be setup
-				CSharpLanguage::get_singleton()->setup_csharp_script_binding(script_binding, owner);
-				CRASH_COND(!script_binding.inited);
-			}
-		}
+		CRASH_COND(!script_binding.inited);
 
 #ifdef DEBUG_ENABLED
 		// The "instance binding" holds a reference so the refcount should be at least 2 before `scope_keep_owner_alive` goes out of scope
 		CRASH_COND(rc_owner->reference_get_count() <= 1);
 #endif
-#endif
 	}
 
 	if (script.is_valid() && owner) {
@@ -3100,10 +3111,10 @@ CSharpInstance *CSharpScript::_create_instance(const Variant **p_args, int p_arg
 		// Hold it alive. Important if we have to dispose a script instance binding before creating the CSharpInstance.
 		ref = Ref<RefCounted>(static_cast<RefCounted *>(p_owner));
 	}
-#if 0
+
 	// If the object had a script instance binding, dispose it before adding the CSharpInstance
-	if (p_owner->has_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index())) {
-		void *data = p_owner->get_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index());
+	if (CSharpLanguage::has_instance_binding(p_owner)) {
+		void *data = CSharpLanguage::get_existing_instance_binding(p_owner);
 		CRASH_COND(data == nullptr);
 
 		CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)data)->get();
@@ -3122,7 +3133,7 @@ CSharpInstance *CSharpScript::_create_instance(const Variant **p_args, int p_arg
 			script_binding.inited = false;
 		}
 	}
-#endif
+
 	CSharpInstance *instance = memnew(CSharpInstance(Ref<CSharpScript>(this)));
 	instance->base_ref_counted = p_is_ref_counted;
 	instance->owner = p_owner;
@@ -3192,7 +3203,7 @@ Variant CSharpScript::_new(const Variant **p_args, int p_argcount, Callable::Cal
 	CSharpInstance *instance = _create_instance(p_args, p_argcount, owner, r != nullptr, r_error);
 	if (!instance) {
 		if (ref.is_null()) {
-			memdelete(owner); //no owner, sorry
+			memdelete(owner); // no owner, sorry
 		}
 		return Variant();
 	}
diff --git a/modules/mono/csharp_script.h b/modules/mono/csharp_script.h
index da6b60aee2..4552f376d0 100644
--- a/modules/mono/csharp_script.h
+++ b/modules/mono/csharp_script.h
@@ -401,7 +401,18 @@ class CSharpLanguage : public ScriptLanguage {
 	static void _editor_init_callback();
 #endif
 
+	static void *_instance_binding_create_callback(void *p_token, void *p_instance);
+	static void _instance_binding_free_callback(void *p_token, void *p_instance, void *p_binding);
+	static GDNativeBool _instance_binding_reference_callback(void *p_token, void *p_binding, GDNativeBool p_reference);
+
+	static GDNativeInstanceBindingCallbacks _instance_binding_callbacks;
+
 public:
+	static void *get_instance_binding(Object *p_object);
+	static void *get_existing_instance_binding(Object *p_object);
+	static void set_instance_binding(Object *p_object, void *p_binding);
+	static bool has_instance_binding(Object *p_object);
+
 	StringNameCache string_names;
 
 	const Mutex &get_language_bind_mutex() { return language_bind_mutex; }
@@ -507,12 +518,6 @@ public:
 	void thread_enter() override;
 	void thread_exit() override;
 
-	// Don't use these. I'm watching you
-	void *alloc_instance_binding_data(Object *p_object) override;
-	void free_instance_binding_data(void *p_data) override;
-	void refcount_incremented_instance_binding(Object *p_object) override;
-	bool refcount_decremented_instance_binding(Object *p_object) override;
-
 	Map<Object *, CSharpScriptBinding>::Element *insert_script_binding(Object *p_object, const CSharpScriptBinding &p_script_binding);
 	bool setup_csharp_script_binding(CSharpScriptBinding &r_script_binding, Object *p_object);
 
diff --git a/modules/mono/glue/base_object_glue.cpp b/modules/mono/glue/base_object_glue.cpp
index a99dff8432..6c5503a3bd 100644
--- a/modules/mono/glue/base_object_glue.cpp
+++ b/modules/mono/glue/base_object_glue.cpp
@@ -64,8 +64,8 @@ void godot_icall_Object_Disposed(MonoObject *p_obj, Object *p_ptr) {
 			return;
 		}
 	}
-#if 0
-	void *data = p_ptr->get_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index());
+
+	void *data = CSharpLanguage::get_existing_instance_binding(p_ptr);
 
 	if (data) {
 		CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)data)->get();
@@ -76,7 +76,6 @@ void godot_icall_Object_Disposed(MonoObject *p_obj, Object *p_ptr) {
 			}
 		}
 	}
-#endif
 }
 
 void godot_icall_RefCounted_Disposed(MonoObject *p_obj, Object *p_ptr, MonoBoolean p_is_finalizer) {
@@ -85,7 +84,7 @@ void godot_icall_RefCounted_Disposed(MonoObject *p_obj, Object *p_ptr, MonoBoole
 	// This is only called with RefCounted derived classes
 	CRASH_COND(!Object::cast_to<RefCounted>(p_ptr));
 #endif
-#if 0
+
 	RefCounted *rc = static_cast<RefCounted *>(p_ptr);
 
 	if (rc->get_script_instance()) {
@@ -113,7 +112,7 @@ void godot_icall_RefCounted_Disposed(MonoObject *p_obj, Object *p_ptr, MonoBoole
 	if (rc->unreference()) {
 		memdelete(rc);
 	} else {
-		void *data = rc->get_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index());
+		void *data = CSharpLanguage::get_existing_instance_binding(rc);
 
 		if (data) {
 			CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)data)->get();
@@ -125,7 +124,6 @@ void godot_icall_RefCounted_Disposed(MonoObject *p_obj, Object *p_ptr, MonoBoole
 			}
 		}
 	}
-#endif
 }
 
 void godot_icall_Object_ConnectEventSignals(Object *p_ptr) {
diff --git a/modules/mono/mono_gd/gd_mono_internals.cpp b/modules/mono/mono_gd/gd_mono_internals.cpp
index d6545d50ec..60047545c4 100644
--- a/modules/mono/mono_gd/gd_mono_internals.cpp
+++ b/modules/mono/mono_gd/gd_mono_internals.cpp
@@ -45,7 +45,7 @@
 namespace GDMonoInternals {
 void tie_managed_to_unmanaged(MonoObject *managed, Object *unmanaged) {
 	// This method should not fail
-#if 0
+
 	CRASH_COND(!unmanaged);
 
 	// All mono objects created from the managed world (e.g.: 'new Player()')
@@ -89,12 +89,12 @@ void tie_managed_to_unmanaged(MonoObject *managed, Object *unmanaged) {
 		}
 
 		// The object was just created, no script instance binding should have been attached
-		CRASH_COND(unmanaged->has_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index()));
+		CRASH_COND(CSharpLanguage::has_instance_binding(unmanaged));
 
 		void *data = (void *)CSharpLanguage::get_singleton()->insert_script_binding(unmanaged, script_binding);
 
 		// Should be thread safe because the object was just created and nothing else should be referencing it
-		unmanaged->set_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index(), data);
+		CSharpLanguage::set_instance_binding(unmanaged, data);
 
 		return;
 	}
@@ -108,7 +108,6 @@ void tie_managed_to_unmanaged(MonoObject *managed, Object *unmanaged) {
 	CSharpInstance *csharp_instance = CSharpInstance::create_for_managed_type(unmanaged, script.ptr(), gchandle);
 
 	unmanaged->set_script_and_instance(script, csharp_instance);
-#endif
 }
 
 void unhandled_exception(MonoException *p_exc) {
diff --git a/modules/mono/mono_gd/gd_mono_utils.cpp b/modules/mono/mono_gd/gd_mono_utils.cpp
index 080398c997..13939bd014 100644
--- a/modules/mono/mono_gd/gd_mono_utils.cpp
+++ b/modules/mono/mono_gd/gd_mono_utils.cpp
@@ -54,7 +54,6 @@
 namespace GDMonoUtils {
 
 MonoObject *unmanaged_get_managed(Object *unmanaged) {
-#if 0
 	if (!unmanaged) {
 		return nullptr;
 	}
@@ -69,22 +68,10 @@ MonoObject *unmanaged_get_managed(Object *unmanaged) {
 
 	// If the owner does not have a CSharpInstance...
 
-	void *data = unmanaged->get_script_instance_binding(CSharpLanguage::get_singleton()->get_language_index());
-
+	void *data = CSharpLanguage::get_instance_binding(unmanaged);
 	ERR_FAIL_NULL_V(data, nullptr);
-
 	CSharpScriptBinding &script_binding = ((Map<Object *, CSharpScriptBinding>::Element *)data)->value();
-
-	if (!script_binding.inited) {
-		MutexLock lock(CSharpLanguage::get_singleton()->get_language_bind_mutex());
-
-		if (!script_binding.inited) { // Other thread may have set it up
-			// Already had a binding that needs to be setup
-			CSharpLanguage::get_singleton()->setup_csharp_script_binding(script_binding, unmanaged);
-
-			ERR_FAIL_COND_V(!script_binding.inited, nullptr);
-		}
-	}
+	ERR_FAIL_COND_V(!script_binding.inited, nullptr);
 
 	MonoGCHandleData &gchandle = script_binding.gchandle;
 
@@ -121,8 +108,6 @@ MonoObject *unmanaged_get_managed(Object *unmanaged) {
 	}
 
 	return mono_object;
-#endif
-	return nullptr;
 }
 
 void set_main_thread(MonoThread *p_thread) {