godot/modules/mono/signal_awaiter_utils.cpp

/*************************************************************************/
/*  signal_awaiter_utils.cpp                                             */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "signal_awaiter_utils.h"

#include "csharp_script.h"
#include "mono_gd/gd_mono_cache.h"
#include "mono_gd/gd_mono_class.h"
#include "mono_gd/gd_mono_marshal.h"
#include "mono_gd/gd_mono_utils.h"

namespace SignalAwaiterUtils {

Error connect_signal_awaiter(Object *p_source, const String &p_signal, Object *p_target, MonoObject *p_awaiter) {
	ERR_FAIL_NULL_V(p_source, ERR_INVALID_DATA);
	ERR_FAIL_NULL_V(p_target, ERR_INVALID_DATA);

	Ref<SignalAwaiterHandle> sa_con = memnew(SignalAwaiterHandle(p_awaiter));
#ifdef DEBUG_ENABLED
	sa_con->set_connection_target(p_target);
#endif

	Vector<Variant> binds;
	binds.push_back(sa_con);

	Error err = p_source->connect(p_signal, sa_con.ptr(),
			CSharpLanguage::get_singleton()->get_string_names()._signal_callback,
			binds, Object::CONNECT_ONESHOT);

	if (err != OK) {
		// Set it as completed to prevent it from calling the failure callback when released.
		// The awaiter will be aware of the failure by checking the returned error.
		sa_con->set_completed(true);
	}

	return err;
}
} // namespace SignalAwaiterUtils

Variant SignalAwaiterHandle::_signal_callback(const Variant **p_args, int p_argcount, Variant::CallError &r_error) {
#ifdef DEBUG_ENABLED
	ERR_FAIL_COND_V_MSG(conn_target_id && !ObjectDB::get_instance(conn_target_id), Variant(),
			"Resumed after await, but class instance is gone.");
#endif

	if (p_argcount < 1) {
		r_error.error = Variant::CallError::CALL_ERROR_TOO_FEW_ARGUMENTS;
		r_error.argument = 1;
		return Variant();
	}

	Ref<SignalAwaiterHandle> self = *p_args[p_argcount - 1];

	if (self.is_null()) {
		r_error.error = Variant::CallError::CALL_ERROR_INVALID_ARGUMENT;
		r_error.argument = p_argcount - 1;
		r_error.expected = Variant::OBJECT;
		return Variant();
	}

	set_completed(true);

	int signal_argc = p_argcount - 1;
	MonoArray *signal_args = mono_array_new(mono_domain_get(), CACHED_CLASS_RAW(MonoObject), signal_argc);

	for (int i = 0; i < signal_argc; i++) {
		MonoObject *boxed = GDMonoMarshal::variant_to_mono_object(*p_args[i]);
		mono_array_setref(signal_args, i, boxed);
	}

	MonoException *exc = NULL;
	GD_MONO_BEGIN_RUNTIME_INVOKE;
	CACHED_METHOD_THUNK(SignalAwaiter, SignalCallback).invoke(get_target(), signal_args, &exc);
	GD_MONO_END_RUNTIME_INVOKE;

	if (exc) {
		GDMonoUtils::set_pending_exception(exc);
		ERR_FAIL_V(Variant());
	}

	return Variant();
}

void SignalAwaiterHandle::_bind_methods() {
	ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "_signal_callback", &SignalAwaiterHandle::_signal_callback, MethodInfo("_signal_callback"));
}

SignalAwaiterHandle::SignalAwaiterHandle(MonoObject *p_managed) :
		MonoGCHandle(MonoGCHandle::new_strong_handle(p_managed), STRONG_HANDLE) {
#ifdef DEBUG_ENABLED
	conn_target_id = 0;
#endif
}

SignalAwaiterHandle::~SignalAwaiterHandle() {
	if (!completed) {
		MonoObject *awaiter = get_target();

		if (awaiter) {
			MonoException *exc = NULL;
			GD_MONO_BEGIN_RUNTIME_INVOKE;
			CACHED_METHOD_THUNK(SignalAwaiter, FailureCallback).invoke(awaiter, &exc);
			GD_MONO_END_RUNTIME_INVOKE;

			if (exc) {
				GDMonoUtils::set_pending_exception(exc);
				ERR_FAIL();
			}
		}
	}
}