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/*
* Copyright (c) 2021, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Optional.h>
#include <AK/StdLibExtras.h>
#include <LibJS/Runtime/VM.h>
#include <LibWeb/Bindings/DOMExceptionWrapper.h>
#include <LibWeb/DOM/ExceptionOr.h>
namespace Web::Bindings {
template<typename>
constexpr bool IsExceptionOr = false;
template<typename T>
constexpr bool IsExceptionOr<DOM::ExceptionOr<T>> = true;
template<typename T>
ALWAYS_INLINE bool throw_dom_exception(JS::VM& vm, JS::GlobalObject& global_object, DOM::ExceptionOr<T>& result)
{
if (result.is_exception()) {
result.materialized_exception(global_object)
.visit(
[&](NonnullRefPtr<DOM::DOMException> dom_exception) { vm.throw_exception(global_object, DOMExceptionWrapper::create(global_object, move(dom_exception))); },
[&](auto* js_exception) { vm.throw_exception(global_object, js_exception); });
return true;
}
return false;
}
namespace Detail {
template<typename T>
struct ExtractExceptionOrValueType {
using Type = T;
};
template<typename T>
struct ExtractExceptionOrValueType<DOM::ExceptionOr<T>> {
using Type = T;
};
template<>
struct ExtractExceptionOrValueType<void> {
using Type = JS::Value;
};
template<>
struct ExtractExceptionOrValueType<DOM::ExceptionOr<Empty>> {
using Type = JS::Value;
};
template<>
struct ExtractExceptionOrValueType<DOM::ExceptionOr<void>> {
using Type = JS::Value;
};
}
template<typename T>
using ExtractExceptionOrValueType = typename Detail::ExtractExceptionOrValueType<T>::Type;
// Return type depends on the return type of 'fn' (when invoked with no args):
// void or ExceptionOr<void>: Optional<JS::Value>, always returns JS::js_undefined()
// ExceptionOr<T>: Optional<T>
// T: Optional<T>
template<typename F, typename T = decltype(declval<F>()()), typename Ret = Conditional<!IsExceptionOr<T> && !IsVoid<T>, T, ExtractExceptionOrValueType<T>>>
Optional<Ret> throw_dom_exception_if_needed(auto&& vm, auto&& global_object, F&& fn)
{
if constexpr (IsExceptionOr<T>) {
auto&& result = fn();
if (throw_dom_exception(vm, global_object, result))
return {};
if constexpr (requires(T v) { v.value(); })
return result.value();
else
return JS::js_undefined();
} else if constexpr (IsVoid<T>) {
fn();
return JS::js_undefined();
} else {
return fn();
}
}
template<typename T>
bool should_return_empty(const Optional<T>& value)
{
if constexpr (IsSame<JS::Value, T>)
return !value.has_value() || value.value().is_empty();
return !value.has_value();
}
}
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