C#: Restructure code prior move to .NET Core

The main focus here was to remove the majority of code that relied on
Mono's embedding APIs, specially the reflection APIs. The embedding
APIs we still use are the bare minimum we need for things to work.
A lot of code was moved to C#. We no longer deal with any managed
objects (`MonoObject*`, and such) in native code, and all marshaling
is done in C#.

The reason for restructuring the code and move away from embedding APIs
is that once we move to .NET Core, we will be limited by the much more
minimal .NET hosting.

PERFORMANCE REGRESSIONS
-----------------------

Some parts of the code were written with little to no concern about
performance. This includes code that calls into script methods and
accesses script fields, properties and events.
The reason for this is that all of that will be moved to source
generators, so any work prior to that would be a waste of time.

DISABLED FEATURES
-----------------

Some code was removed as it no longer makes sense (or won't make sense
in the future).
Other parts were commented out with `#if 0`s and TODO warnings because
it doesn't make much sense to work on them yet as those parts will
change heavily when we switch to .NET Core but also when we start
introducing source generators.
As such, the following features were disabled temporarily:
- Assembly-reloading (will be done with ALCs in .NET Core).
- Properties/fields exports and script method listing (will be
  handled by source generators in the future).
- Exception logging in the editor and stack info for errors.
- Exporting games.
- Building of C# projects. We no longer copy the Godot API assemblies
  to the project directory, so MSBuild won't be able to find them. The
  idea is to turn them into NuGet packages in the future, which could
  also be obtained from local NuGet sources during development.

1 files changed, 0 insertions, 569 deletions

diff --git a/modules/mono/mono_gd/gd_mono_class.cpp b/modules/mono/mono_gd/gd_mono_class.cpp
deleted file mode 100644
index 24b46d2ce8..0000000000
--- a/modules/mono/mono_gd/gd_mono_class.cpp
+++ /dev/null
@@ -1,569 +0,0 @@
-/*************************************************************************/
-/*  gd_mono_class.cpp                                                    */
-/*************************************************************************/
-/*                       This file is part of:                           */
-/*                           GODOT ENGINE                                */
-/*                      https://godotengine.org                          */
-/*************************************************************************/
-/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
-/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
-/*                                                                       */
-/* Permission is hereby granted, free of charge, to any person obtaining */
-/* a copy of this software and associated documentation files (the       */
-/* "Software"), to deal in the Software without restriction, including   */
-/* without limitation the rights to use, copy, modify, merge, publish,   */
-/* distribute, sublicense, and/or sell copies of the Software, and to    */
-/* permit persons to whom the Software is furnished to do so, subject to */
-/* the following conditions:                                             */
-/*                                                                       */
-/* The above copyright notice and this permission notice shall be        */
-/* included in all copies or substantial portions of the Software.       */
-/*                                                                       */
-/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
-/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
-/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
-/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
-/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
-/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
-/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
-/*************************************************************************/
-
-#include "gd_mono_class.h"
-
-#include <mono/metadata/attrdefs.h>
-#include <mono/metadata/debug-helpers.h>
-
-#include "gd_mono_assembly.h"
-#include "gd_mono_cache.h"
-#include "gd_mono_marshal.h"
-
-String GDMonoClass::get_full_name(MonoClass *p_mono_class) {
-	// mono_type_get_full_name is not exposed to embedders, but this seems to do the job
-	MonoReflectionType *type_obj = mono_type_get_object(mono_domain_get(), get_mono_type(p_mono_class));
-
-	MonoException *exc = nullptr;
-	MonoString *str = GDMonoUtils::object_to_string((MonoObject *)type_obj, &exc);
-	UNHANDLED_EXCEPTION(exc);
-
-	return GDMonoMarshal::mono_string_to_godot(str);
-}
-
-MonoType *GDMonoClass::get_mono_type(MonoClass *p_mono_class) {
-	return mono_class_get_type(p_mono_class);
-}
-
-String GDMonoClass::get_full_name() const {
-	return get_full_name(mono_class);
-}
-
-String GDMonoClass::get_type_desc() const {
-	return GDMonoUtils::get_type_desc(get_mono_type());
-}
-
-MonoType *GDMonoClass::get_mono_type() const {
-	// Careful, you cannot compare two MonoType*.
-	// There is mono_metadata_type_equal, how is this different from comparing two MonoClass*?
-	return get_mono_type(mono_class);
-}
-
-uint32_t GDMonoClass::get_flags() const {
-	return mono_class_get_flags(mono_class);
-}
-
-bool GDMonoClass::is_static() const {
-	uint32_t static_class_flags = MONO_TYPE_ATTR_ABSTRACT | MONO_TYPE_ATTR_SEALED;
-	return (get_flags() & static_class_flags) == static_class_flags;
-}
-
-bool GDMonoClass::is_assignable_from(GDMonoClass *p_from) const {
-	return mono_class_is_assignable_from(mono_class, p_from->mono_class);
-}
-
-StringName GDMonoClass::get_namespace() const {
-	GDMonoClass *nesting_class = get_nesting_class();
-	if (!nesting_class) {
-		return namespace_name;
-	}
-	return nesting_class->get_namespace();
-}
-
-String GDMonoClass::get_name_for_lookup() const {
-	GDMonoClass *nesting_class = get_nesting_class();
-	if (!nesting_class) {
-		return class_name;
-	}
-	return nesting_class->get_name_for_lookup() + "/" + class_name;
-}
-
-GDMonoClass *GDMonoClass::get_parent_class() const {
-	MonoClass *parent_mono_class = mono_class_get_parent(mono_class);
-	return parent_mono_class ? GDMono::get_singleton()->get_class(parent_mono_class) : nullptr;
-}
-
-GDMonoClass *GDMonoClass::get_nesting_class() const {
-	MonoClass *nesting_type = mono_class_get_nesting_type(mono_class);
-	return nesting_type ? GDMono::get_singleton()->get_class(nesting_type) : nullptr;
-}
-
-#ifdef TOOLS_ENABLED
-Vector<MonoClassField *> GDMonoClass::get_enum_fields() {
-	bool class_is_enum = mono_class_is_enum(mono_class);
-	ERR_FAIL_COND_V(!class_is_enum, Vector<MonoClassField *>());
-
-	Vector<MonoClassField *> enum_fields;
-
-	void *iter = nullptr;
-	MonoClassField *raw_field = nullptr;
-	while ((raw_field = mono_class_get_fields(get_mono_ptr(), &iter)) != nullptr) {
-		uint32_t field_flags = mono_field_get_flags(raw_field);
-
-		// Enums have an instance field named value__ which holds the value of the enum.
-		// Enum constants are static, so we will use this to ignore the value__ field.
-		if (field_flags & MONO_FIELD_ATTR_PUBLIC && field_flags & MONO_FIELD_ATTR_STATIC) {
-			enum_fields.push_back(raw_field);
-		}
-	}
-
-	return enum_fields;
-}
-#endif
-
-bool GDMonoClass::has_attribute(GDMonoClass *p_attr_class) {
-#ifdef DEBUG_ENABLED
-	ERR_FAIL_NULL_V(p_attr_class, false);
-#endif
-
-	if (!attrs_fetched) {
-		fetch_attributes();
-	}
-
-	if (!attributes) {
-		return false;
-	}
-
-	return mono_custom_attrs_has_attr(attributes, p_attr_class->get_mono_ptr());
-}
-
-MonoObject *GDMonoClass::get_attribute(GDMonoClass *p_attr_class) {
-#ifdef DEBUG_ENABLED
-	ERR_FAIL_NULL_V(p_attr_class, nullptr);
-#endif
-
-	if (!attrs_fetched) {
-		fetch_attributes();
-	}
-
-	if (!attributes) {
-		return nullptr;
-	}
-
-	return mono_custom_attrs_get_attr(attributes, p_attr_class->get_mono_ptr());
-}
-
-void GDMonoClass::fetch_attributes() {
-	ERR_FAIL_COND(attributes != nullptr);
-
-	attributes = mono_custom_attrs_from_class(get_mono_ptr());
-	attrs_fetched = true;
-}
-
-void GDMonoClass::fetch_methods_with_godot_api_checks(GDMonoClass *p_native_base) {
-	CRASH_COND(!CACHED_CLASS(GodotObject)->is_assignable_from(this));
-
-	if (methods_fetched) {
-		return;
-	}
-
-	void *iter = nullptr;
-	MonoMethod *raw_method = nullptr;
-	while ((raw_method = mono_class_get_methods(get_mono_ptr(), &iter)) != nullptr) {
-		StringName name = String::utf8(mono_method_get_name(raw_method));
-
-		// get_method implicitly fetches methods and adds them to this->methods
-		GDMonoMethod *method = get_method(raw_method, name);
-		ERR_CONTINUE(!method);
-
-		if (method->get_name() != name) {
-#ifdef DEBUG_ENABLED
-			String fullname = method->get_ret_type_full_name() + " " + name + "(" + method->get_signature_desc(true) + ")";
-			WARN_PRINT("Method '" + fullname + "' is hidden by Godot API method. Should be '" +
-					method->get_full_name_no_class() + "'. In class '" + namespace_name + "." + class_name + "'.");
-#endif
-			continue;
-		}
-
-#ifdef DEBUG_ENABLED
-		// For debug builds, we also fetched from native base classes as well before if this is not a native base class.
-		// This allows us to warn the user here if they are using snake_case by mistake.
-
-		if (p_native_base != this) {
-			GDMonoClass *native_top = p_native_base;
-			while (native_top) {
-				GDMonoMethod *m = native_top->get_method(name, method->get_parameters_count());
-
-				if (m && m->get_name() != name) {
-					// found
-					String fullname = m->get_ret_type_full_name() + " " + name + "(" + m->get_signature_desc(true) + ")";
-					WARN_PRINT("Method '" + fullname + "' should be '" + m->get_full_name_no_class() +
-							"'. In class '" + namespace_name + "." + class_name + "'.");
-					break;
-				}
-
-				if (native_top == CACHED_CLASS(GodotObject)) {
-					break;
-				}
-
-				native_top = native_top->get_parent_class();
-			}
-		}
-#endif
-
-		uint32_t flags = mono_method_get_flags(method->mono_method, nullptr);
-
-		if (!(flags & MONO_METHOD_ATTR_VIRTUAL)) {
-			continue;
-		}
-
-		// Virtual method of Godot Object derived type, let's try to find GodotMethod attribute
-
-		GDMonoClass *top = p_native_base;
-
-		while (top) {
-			GDMonoMethod *base_method = top->get_method(name, method->get_parameters_count());
-
-			if (base_method && base_method->has_attribute(CACHED_CLASS(GodotMethodAttribute))) {
-				// Found base method with GodotMethod attribute.
-				// We get the original API method name from this attribute.
-				// This name must point to the virtual method.
-
-				MonoObject *attr = base_method->get_attribute(CACHED_CLASS(GodotMethodAttribute));
-
-				StringName godot_method_name = CACHED_FIELD(GodotMethodAttribute, methodName)->get_string_value(attr);
-#ifdef DEBUG_ENABLED
-				CRASH_COND(godot_method_name == StringName());
-#endif
-				MethodKey key = MethodKey(godot_method_name, method->get_parameters_count());
-				GDMonoMethod **existing_method = methods.getptr(key);
-				if (existing_method) {
-					memdelete(*existing_method); // Must delete old one
-				}
-				methods.insert(key, method);
-
-				break;
-			}
-
-			if (top == CACHED_CLASS(GodotObject)) {
-				break;
-			}
-
-			top = top->get_parent_class();
-		}
-	}
-
-	methods_fetched = true;
-}
-
-GDMonoMethod *GDMonoClass::get_fetched_method_unknown_params(const StringName &p_name) {
-	ERR_FAIL_COND_V(!methods_fetched, nullptr);
-
-	for (const KeyValue<MethodKey, GDMonoMethod *> &E : methods) {
-		if (E.key.name == p_name) {
-			return E.value;
-		}
-	}
-
-	return nullptr;
-}
-
-bool GDMonoClass::has_fetched_method_unknown_params(const StringName &p_name) {
-	return get_fetched_method_unknown_params(p_name) != nullptr;
-}
-
-bool GDMonoClass::implements_interface(GDMonoClass *p_interface) {
-	return mono_class_implements_interface(mono_class, p_interface->get_mono_ptr());
-}
-
-bool GDMonoClass::has_public_parameterless_ctor() {
-	GDMonoMethod *ctor = get_method(".ctor", 0);
-	return ctor && ctor->get_visibility() == IMonoClassMember::PUBLIC;
-}
-
-GDMonoMethod *GDMonoClass::get_method(const StringName &p_name, uint16_t p_params_count) {
-	MethodKey key = MethodKey(p_name, p_params_count);
-
-	GDMonoMethod **match = methods.getptr(key);
-
-	if (match) {
-		return *match;
-	}
-
-	if (methods_fetched) {
-		return nullptr;
-	}
-
-	MonoMethod *raw_method = mono_class_get_method_from_name(mono_class, String(p_name).utf8().get_data(), p_params_count);
-
-	if (raw_method) {
-		GDMonoMethod *method = memnew(GDMonoMethod(p_name, raw_method));
-		methods.insert(key, method);
-
-		return method;
-	}
-
-	return nullptr;
-}
-
-GDMonoMethod *GDMonoClass::get_method(MonoMethod *p_raw_method) {
-	MonoMethodSignature *sig = mono_method_signature(p_raw_method);
-
-	int params_count = mono_signature_get_param_count(sig);
-	StringName method_name = String::utf8(mono_method_get_name(p_raw_method));
-
-	return get_method(p_raw_method, method_name, params_count);
-}
-
-GDMonoMethod *GDMonoClass::get_method(MonoMethod *p_raw_method, const StringName &p_name) {
-	MonoMethodSignature *sig = mono_method_signature(p_raw_method);
-	int params_count = mono_signature_get_param_count(sig);
-	return get_method(p_raw_method, p_name, params_count);
-}
-
-GDMonoMethod *GDMonoClass::get_method(MonoMethod *p_raw_method, const StringName &p_name, uint16_t p_params_count) {
-	ERR_FAIL_NULL_V(p_raw_method, nullptr);
-
-	MethodKey key = MethodKey(p_name, p_params_count);
-
-	GDMonoMethod **match = methods.getptr(key);
-
-	if (match) {
-		return *match;
-	}
-
-	GDMonoMethod *method = memnew(GDMonoMethod(p_name, p_raw_method));
-	methods.insert(key, method);
-
-	return method;
-}
-
-GDMonoMethod *GDMonoClass::get_method_with_desc(const String &p_description, bool p_include_namespace) {
-	MonoMethodDesc *desc = mono_method_desc_new(p_description.utf8().get_data(), p_include_namespace);
-	MonoMethod *method = mono_method_desc_search_in_class(desc, mono_class);
-	mono_method_desc_free(desc);
-
-	if (!method) {
-		return nullptr;
-	}
-
-	ERR_FAIL_COND_V(mono_method_get_class(method) != mono_class, nullptr);
-
-	return get_method(method);
-}
-
-GDMonoField *GDMonoClass::get_field(const StringName &p_name) {
-	HashMap<StringName, GDMonoField *>::Iterator result = fields.find(p_name);
-
-	if (result) {
-		return result->value;
-	}
-
-	if (fields_fetched) {
-		return nullptr;
-	}
-
-	MonoClassField *raw_field = mono_class_get_field_from_name(mono_class, String(p_name).utf8().get_data());
-
-	if (raw_field) {
-		GDMonoField *field = memnew(GDMonoField(raw_field, this));
-		fields.insert(p_name, field);
-
-		return field;
-	}
-
-	return nullptr;
-}
-
-const Vector<GDMonoField *> &GDMonoClass::get_all_fields() {
-	if (fields_fetched) {
-		return fields_list;
-	}
-
-	void *iter = nullptr;
-	MonoClassField *raw_field = nullptr;
-	while ((raw_field = mono_class_get_fields(mono_class, &iter)) != nullptr) {
-		StringName name = String::utf8(mono_field_get_name(raw_field));
-
-		HashMap<StringName, GDMonoField *>::Iterator match = fields.find(name);
-
-		if (match) {
-			fields_list.push_back(match->value);
-		} else {
-			GDMonoField *field = memnew(GDMonoField(raw_field, this));
-			fields.insert(name, field);
-			fields_list.push_back(field);
-		}
-	}
-
-	fields_fetched = true;
-
-	return fields_list;
-}
-
-GDMonoProperty *GDMonoClass::get_property(const StringName &p_name) {
-	HashMap<StringName, GDMonoProperty *>::Iterator result = properties.find(p_name);
-
-	if (result) {
-		return result->value;
-	}
-
-	if (properties_fetched) {
-		return nullptr;
-	}
-
-	MonoProperty *raw_property = mono_class_get_property_from_name(mono_class, String(p_name).utf8().get_data());
-
-	if (raw_property) {
-		GDMonoProperty *property = memnew(GDMonoProperty(raw_property, this));
-		properties.insert(p_name, property);
-
-		return property;
-	}
-
-	return nullptr;
-}
-
-const Vector<GDMonoProperty *> &GDMonoClass::get_all_properties() {
-	if (properties_fetched) {
-		return properties_list;
-	}
-
-	void *iter = nullptr;
-	MonoProperty *raw_property = nullptr;
-	while ((raw_property = mono_class_get_properties(mono_class, &iter)) != nullptr) {
-		StringName name = String::utf8(mono_property_get_name(raw_property));
-
-		HashMap<StringName, GDMonoProperty *>::Iterator match = properties.find(name);
-
-		if (match) {
-			properties_list.push_back(match->value);
-		} else {
-			GDMonoProperty *property = memnew(GDMonoProperty(raw_property, this));
-			properties.insert(name, property);
-			properties_list.push_back(property);
-		}
-	}
-
-	properties_fetched = true;
-
-	return properties_list;
-}
-
-const Vector<GDMonoClass *> &GDMonoClass::get_all_delegates() {
-	if (delegates_fetched) {
-		return delegates_list;
-	}
-
-	// NOTE: Temporarily reverted d28be4d5808947606b8189ae1b2900b8fd2925cf, while we move code to C#
-
-	void *iter = nullptr;
-	MonoClass *raw_class = nullptr;
-	while ((raw_class = mono_class_get_nested_types(mono_class, &iter)) != nullptr) {
-		if (mono_class_is_delegate(raw_class)) {
-			StringName name = String::utf8(mono_class_get_name(raw_class));
-
-			HashMap<StringName, GDMonoClass *>::Iterator match = delegates.find(name);
-
-			if (match) {
-				delegates_list.push_back(match->value);
-			} else {
-				GDMonoClass *delegate = memnew(GDMonoClass(String::utf8(mono_class_get_namespace(raw_class)), String::utf8(mono_class_get_name(raw_class)), raw_class, assembly));
-				delegates.insert(name, delegate);
-				delegates_list.push_back(delegate);
-			}
-		}
-	}
-
-	delegates_fetched = true;
-
-	return delegates_list;
-}
-
-const Vector<GDMonoMethod *> &GDMonoClass::get_all_methods() {
-	if (!method_list_fetched) {
-		void *iter = nullptr;
-		MonoMethod *raw_method = nullptr;
-		while ((raw_method = mono_class_get_methods(get_mono_ptr(), &iter)) != nullptr) {
-			method_list.push_back(memnew(GDMonoMethod(String::utf8(mono_method_get_name(raw_method)), raw_method)));
-		}
-
-		method_list_fetched = true;
-	}
-
-	return method_list;
-}
-
-GDMonoClass::GDMonoClass(const StringName &p_namespace, const StringName &p_name, MonoClass *p_class, GDMonoAssembly *p_assembly) {
-	namespace_name = p_namespace;
-	class_name = p_name;
-	mono_class = p_class;
-	assembly = p_assembly;
-
-	attrs_fetched = false;
-	attributes = nullptr;
-
-	methods_fetched = false;
-	method_list_fetched = false;
-	fields_fetched = false;
-	properties_fetched = false;
-	delegates_fetched = false;
-}
-
-GDMonoClass::~GDMonoClass() {
-	if (attributes) {
-		mono_custom_attrs_free(attributes);
-	}
-
-	for (const KeyValue<StringName, GDMonoField *> &E : fields) {
-		memdelete(E.value);
-	}
-
-	for (const KeyValue<StringName, GDMonoProperty *> &E : properties) {
-		memdelete(E.value);
-	}
-
-	{
-		// Ugly workaround...
-		// We may have duplicated values, because we redirect snake_case methods to PascalCasel (only Godot API methods).
-		// This way, we end with both the snake_case name and the PascalCasel name paired with the same method.
-		// Therefore, we must avoid deleting the same pointer twice.
-
-		int offset = 0;
-		Vector<GDMonoMethod *> deleted_methods;
-		deleted_methods.resize(methods.size());
-
-		for (const KeyValue<MethodKey, GDMonoMethod *> &E : methods) {
-			GDMonoMethod *method = E.value;
-
-			if (method) {
-				for (int i = 0; i < offset; i++) {
-					if (deleted_methods[i] == method) {
-						// Already deleted
-						goto already_deleted;
-					}
-				}
-
-				deleted_methods.write[offset] = method;
-				++offset;
-
-				memdelete(method);
-			}
-
-		already_deleted:;
-		}
-
-		methods.clear();
-	}
-
-	for (int i = 0; i < method_list.size(); ++i) {
-		memdelete(method_list[i]);
-	}
-}