godot/modules/mono/mono_gd/gd_mono_utils.h
Ignacio Roldán Etcheverry 483071716e C#: Move marshaling logic and generated glue to C#
We will be progressively moving most code to C#.
The plan is to only use Mono's embedding APIs to set things at launch.
This will make it much easier to later support CoreCLR too which
doesn't have rich embedding APIs.

Additionally the code in C# is more maintainable and makes it easier
to implement new features, e.g.: runtime codegen which we could use to
avoid using reflection for marshaling everytime a field, property or
method is accessed.

SOME NOTES ON INTEROP

We make the same assumptions as GDNative about the size of the Godot
structures we use. We take it a bit further by also assuming the layout
of fields in some cases, which is riskier but let's us squeeze out some
performance by avoiding unnecessary managed to native calls.

Code that deals with native structs is less safe than before as there's
no RAII and copy constructors in C#. It's like using the GDNative C API
directly. One has to take special care to free values they own.
Perhaps we could use roslyn analyzers to check this, but I don't know
any that uses attributes to determine what's owned or borrowed.

As to why we maily use pointers for native structs instead of ref/out:
- AFAIK (and confirmed with a benchmark) ref/out are pinned
  during P/Invoke calls and that has a cost.
- Native struct fields can't be ref/out in the first place.
- A `using` local can't be passed as ref/out, only `in`. Calling a
  method or property on an `in` value makes a silent copy, so we want
  to avoid `in`.

REGARDING THE BUILD SYSTEM

There's no longer a `mono_glue=yes/no` SCons options. We no longer
need to build with `mono_glue=no`, generate the glue and then build
again with `mono_glue=yes`. We build only once and generate the glue
(which is in C# now).
However, SCons no longer builds the C# projects for us. Instead one
must run `build_assemblies.py`, e.g.:
```sh
%godot_src_root%/modules/mono/build_scripts/build_assemblies.py \
        --godot-output-dir=%godot_src_root%/bin \
        --godot-target=release_debug`
```
We could turn this into a custom build target, but I don't know how
to do that with SCons (it's possible with Meson).

OTHER NOTES

Most of the moved code doesn't follow the C# naming convention and
still has the word Mono in the names despite no longer dealing with
Mono's embedding APIs. This is just temporary while transitioning,
to make it easier to understand what was moved where.
2021-08-20 10:24:56 +02:00

179 lines
7.1 KiB
C++

/*************************************************************************/
/* gd_mono_utils.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2021 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. */
/*************************************************************************/
#ifndef GD_MONOUTILS_H
#define GD_MONOUTILS_H
#include <mono/metadata/threads.h>
#include "../mono_gc_handle.h"
#include "../utils/macros.h"
#include "gd_mono_header.h"
#ifdef JAVASCRIPT_ENABLED
#include "gd_mono_wasm_m2n.h"
#endif
#include "core/object/class_db.h"
#include "core/object/ref_counted.h"
#define UNHANDLED_EXCEPTION(m_exc) \
if (unlikely(m_exc != nullptr)) { \
GDMonoUtils::debug_unhandled_exception(m_exc); \
GD_UNREACHABLE(); \
} else \
((void)0)
namespace GDMonoUtils {
_FORCE_INLINE_ void hash_combine(uint32_t &p_hash, const uint32_t &p_with_hash) {
p_hash ^= p_with_hash + 0x9e3779b9 + (p_hash << 6) + (p_hash >> 2);
}
/**
* If the object has a csharp script, returns the target of the gchandle stored in the script instance
* Otherwise returns a newly constructed MonoObject* which is attached to the object
* Returns nullptr on error
*/
MonoObject *unmanaged_get_managed(Object *unmanaged);
void set_main_thread(MonoThread *p_thread);
MonoThread *attach_current_thread();
void detach_current_thread();
void detach_current_thread(MonoThread *p_mono_thread);
MonoThread *get_current_thread();
bool is_thread_attached();
uint32_t new_strong_gchandle(MonoObject *p_object);
uint32_t new_strong_gchandle_pinned(MonoObject *p_object);
uint32_t new_weak_gchandle(MonoObject *p_object);
void free_gchandle(uint32_t p_gchandle);
void runtime_object_init(MonoObject *p_this_obj, GDMonoClass *p_class, MonoException **r_exc = nullptr);
GDMonoClass *get_object_class(MonoObject *p_object);
GDMonoClass *type_get_proxy_class(const StringName &p_type);
GDMonoClass *get_class_native_base(GDMonoClass *p_class);
MonoObject *create_managed_for_godot_object(GDMonoClass *p_class, const StringName &p_native, Object *p_object);
MonoDomain *create_domain(const String &p_friendly_name);
String get_type_desc(MonoType *p_type);
String get_type_desc(MonoReflectionType *p_reftype);
String get_exception_name_and_message(MonoException *p_exc);
void debug_print_unhandled_exception(MonoException *p_exc);
void debug_send_unhandled_exception_error(MonoException *p_exc);
void debug_unhandled_exception(MonoException *p_exc);
void print_unhandled_exception(MonoException *p_exc);
/**
* Sets the exception as pending. The exception will be thrown when returning to managed code.
* If no managed method is being invoked by the runtime, the exception will be treated as
* an unhandled exception and the method will not return.
*/
void set_pending_exception(MonoException *p_exc);
extern thread_local int current_invoke_count;
_FORCE_INLINE_ int get_runtime_invoke_count() {
return current_invoke_count;
}
_FORCE_INLINE_ int &get_runtime_invoke_count_ref() {
return current_invoke_count;
}
MonoObject *runtime_invoke(MonoMethod *p_method, void *p_obj, void **p_params, MonoException **r_exc);
MonoObject *runtime_invoke_array(MonoMethod *p_method, void *p_obj, MonoArray *p_params, MonoException **r_exc);
MonoString *object_to_string(MonoObject *p_obj, MonoException **r_exc);
void property_set_value(MonoProperty *p_prop, void *p_obj, void **p_params, MonoException **r_exc);
MonoObject *property_get_value(MonoProperty *p_prop, void *p_obj, void **p_params, MonoException **r_exc);
uint64_t unbox_enum_value(MonoObject *p_boxed, MonoType *p_enum_basetype, bool &r_error);
void dispose(MonoObject *p_mono_object, MonoException **r_exc);
struct ScopeThreadAttach {
ScopeThreadAttach();
~ScopeThreadAttach();
private:
MonoThread *mono_thread = nullptr;
};
StringName get_native_godot_class_name(GDMonoClass *p_class);
template <typename... P>
void add_internal_call(const char *p_name, void (*p_func)(P...)) {
#ifdef JAVASCRIPT_ENABLED
GDMonoWasmM2n::ICallTrampolines<P...>::add();
#endif
mono_add_internal_call(p_name, (void *)p_func);
}
template <typename R, typename... P>
void add_internal_call(const char *p_name, R (*p_func)(P...)) {
#ifdef JAVASCRIPT_ENABLED
GDMonoWasmM2n::ICallTrampolinesR<R, P...>::add();
#endif
mono_add_internal_call(p_name, (void *)p_func);
}
} // namespace GDMonoUtils
#define NATIVE_GDMONOCLASS_NAME(m_class) (GDMonoUtils::get_native_godot_class_name(m_class))
#define GD_MONO_BEGIN_RUNTIME_INVOKE \
int &_runtime_invoke_count_ref = GDMonoUtils::get_runtime_invoke_count_ref(); \
_runtime_invoke_count_ref += 1; \
((void)0)
#define GD_MONO_END_RUNTIME_INVOKE \
_runtime_invoke_count_ref -= 1; \
((void)0)
#define GD_MONO_SCOPE_THREAD_ATTACH \
GDMonoUtils::ScopeThreadAttach __gdmono__scope__thread__attach__; \
(void)__gdmono__scope__thread__attach__; \
((void)0)
#ifdef DEBUG_ENABLED
#define GD_MONO_ASSERT_THREAD_ATTACHED \
CRASH_COND(!GDMonoUtils::is_thread_attached()); \
((void)0)
#else
#define GD_MONO_ASSERT_THREAD_ATTACHED ((void)0)
#endif
#endif // GD_MONOUTILS_H