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LibWeb: Make ExceptionOr work with non-JS::Value types

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Fixes #6075.
This commit is contained in:
AnotherTest 2021-04-13 23:48:25 +04:30 • committed by Andreas Kling
parent d5def1cad0
commit 8ba2b5f36f
2 changed files with 43 additions and 8 deletions
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45
Userland/Libraries/LibWeb/Bindings/ExceptionOrUtils.h
View file

@ -26,6 +26,7 @@
#pragma once
#include <AK/Optional.h>
#include <AK/StdLibExtras.h>
#include <LibJS/Runtime/VM.h>
#include <LibWeb/Bindings/DOMExceptionWrapper.h>
@ -49,16 +50,48 @@ ALWAYS_INLINE bool throw_dom_exception(JS::VM& vm, JS::GlobalObject& global_obje
return false;
}
template<typename F, typename T = decltype(declval<F>()()), typename Ret = Conditional<!IsExceptionOr<T> && !IsVoid<T>, T, JS::Value>>
Ret throw_dom_exception_if_needed(auto&& vm, auto&& global_object, F&& fn)
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<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 JS::Value();
return {};
if constexpr (requires(T v) { v.value(); })
return result.value();
return JS::Value();
else
return JS::js_undefined();
} else if constexpr (IsVoid<T>) {
fn();
return JS::js_undefined();
@ -68,10 +101,10 @@ Ret throw_dom_exception_if_needed(auto&& vm, auto&& global_object, F&& fn)
}
template<typename T>
bool should_return_empty(T&& value)
bool should_return_empty(const Optional<T>& value)
{
if constexpr (IsSame<JS::Value, T>)
return value.is_empty();
return value.has_value() && value.value().is_empty();
return false;
}

6
Userland/Libraries/LibWeb/CodeGenerators/WrapperGenerator.cpp
View file

@ -1514,9 +1514,11 @@ JS_DEFINE_NATIVE_FUNCTION(@prototype_class@::@function.name:snakecase@)
function_generator.set(".arguments", arguments_builder.string_view());
function_generator.append(R"~~~(
auto retval = throw_dom_exception_if_needed(vm, global_object, [&] { return impl->@function.cpp_name@(@.arguments@); });
if (should_return_empty(retval))
auto result = throw_dom_exception_if_needed(vm, global_object, [&] { return impl->@function.cpp_name@(@.arguments@); });
if (should_return_empty(result))
return JS::Value();
[[maybe_unused]] auto retval = result.release_value();
)~~~");
generate_return_statement(function.return_type);