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	 fd72597999
			
		
	
	
		fd72597999
		
	
	
	
	
		
			
			The WebIDL spec specifies a few "simple" exception types in addition to
the DOMException type, let's support all of those.
This allows functions returning ExceptionOr<T> to throw regular
javascript exceptions (as limited by the webidl spec) by returning a
`DOM::SimpleException { DOM::SimpleExceptionType::T, "error message" }`
which is pretty damn cool :^)
		
	
			
		
			
				
	
	
		
			99 lines
		
	
	
	
		
			2.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			99 lines
		
	
	
	
		
			2.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2021, the SerenityOS developers.
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #pragma once
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| 
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| #include <AK/Optional.h>
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| #include <AK/StdLibExtras.h>
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| #include <LibJS/Runtime/VM.h>
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| #include <LibWeb/Bindings/DOMExceptionWrapper.h>
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| #include <LibWeb/DOM/ExceptionOr.h>
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| 
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| namespace Web::Bindings {
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| 
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| template<typename>
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| constexpr bool IsExceptionOr = false;
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| 
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| template<typename T>
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| constexpr bool IsExceptionOr<DOM::ExceptionOr<T>> = true;
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| 
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| template<typename T>
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| ALWAYS_INLINE bool throw_dom_exception(JS::VM& vm, JS::GlobalObject& global_object, DOM::ExceptionOr<T>& result)
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| {
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|     if (result.is_exception()) {
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|         result.materialized_exception(global_object)
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|             .visit(
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|                 [&](NonnullRefPtr<DOM::DOMException> dom_exception) { vm.throw_exception(global_object, DOMExceptionWrapper::create(global_object, move(dom_exception))); },
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|                 [&](auto* js_exception) { vm.throw_exception(global_object, js_exception); });
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|         return true;
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|     }
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|     return false;
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| }
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| 
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| namespace Detail {
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| 
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| template<typename T>
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| struct ExtractExceptionOrValueType {
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|     using Type = T;
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| };
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| 
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| template<typename T>
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| struct ExtractExceptionOrValueType<DOM::ExceptionOr<T>> {
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|     using Type = T;
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| };
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| 
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| template<>
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| struct ExtractExceptionOrValueType<void> {
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|     using Type = JS::Value;
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| };
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| 
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| template<>
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| struct ExtractExceptionOrValueType<DOM::ExceptionOr<Empty>> {
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|     using Type = JS::Value;
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| };
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| 
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| template<>
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| struct ExtractExceptionOrValueType<DOM::ExceptionOr<void>> {
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|     using Type = JS::Value;
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| };
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| 
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| }
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| 
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| template<typename T>
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| using ExtractExceptionOrValueType = typename Detail::ExtractExceptionOrValueType<T>::Type;
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| 
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| // Return type depends on the return type of 'fn' (when invoked with no args):
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| // void or ExceptionOr<void>: Optional<JS::Value>, always returns JS::js_undefined()
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| // ExceptionOr<T>: Optional<T>
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| // T: Optional<T>
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| template<typename F, typename T = decltype(declval<F>()()), typename Ret = Conditional<!IsExceptionOr<T> && !IsVoid<T>, T, ExtractExceptionOrValueType<T>>>
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| Optional<Ret> throw_dom_exception_if_needed(auto&& vm, auto&& global_object, F&& fn)
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| {
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|     if constexpr (IsExceptionOr<T>) {
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|         auto&& result = fn();
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|         if (throw_dom_exception(vm, global_object, result))
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|             return {};
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|         if constexpr (requires(T v) { v.value(); })
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|             return result.value();
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|         else
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|             return JS::js_undefined();
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|     } else if constexpr (IsVoid<T>) {
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|         fn();
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|         return JS::js_undefined();
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|     } else {
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|         return fn();
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|     }
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| }
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| 
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| template<typename T>
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| bool should_return_empty(const Optional<T>& value)
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| {
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|     if constexpr (IsSame<JS::Value, T>)
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|         return !value.has_value() || value.value().is_empty();
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|     return !value.has_value();
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| }
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| 
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| }
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