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LibJS: Implement IteratorClose with Completions and align to the spec

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Timothy Flynn 2021-10-20 13:36:14 -04:00 • committed by Linus Groh
parent 04b4307b3d
commit ec54a7b5b0
8 changed files with 97 additions and 79 deletions
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72
Userland/Libraries/LibJS/Runtime/IteratorOperations.cpp
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@ -9,6 +9,7 @@
#include <LibJS/Runtime/FunctionObject.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/IteratorOperations.h>
#include <LibJS/Runtime/TemporaryClearException.h>
namespace JS {
@ -87,45 +88,52 @@ ThrowCompletionOr<Object*> iterator_step(GlobalObject& global_object, Object& it
}
// 7.4.6 IteratorClose ( iteratorRecord, completion ), https://tc39.es/ecma262/#sec-iteratorclose
void iterator_close(Object& iterator)
Completion iterator_close(Object& iterator, Completion completion)
{
auto& vm = iterator.vm();
auto& global_object = iterator.global_object();
// Emulates `completion` behavior
auto* completion_exception = vm.exception();
vm.clear_exception();
auto unwind_until = vm.unwind_until();
auto unwind_until_label = vm.unwind_until_label();
vm.stop_unwind();
auto restore_completion = [&]() {
if (completion_exception)
vm.set_exception(*completion_exception);
if (unwind_until != ScopeType::None)
vm.unwind(unwind_until, unwind_until_label);
};
// The callers of iterator_close() are often in an exceptional state.
// Temporarily clear that exception for invocation(s) to Call.
TemporaryClearException clear_exception(vm);
auto return_method_or_error = Value(&iterator).get_method(global_object, vm.names.return_);
Value result;
if (!return_method_or_error.is_error()) { // If innerResult.[[Type]] is normal, then
auto return_method = return_method_or_error.release_value();
// 3. Let innerResult be GetMethod(iterator, "return").
auto inner_result_or_error = Value(&iterator).get_method(global_object, vm.names.return_);
Value inner_result;
// 4. If innerResult.[[Type]] is normal, then
if (!inner_result_or_error.is_error()) {
// a. Let return be innerResult.[[Value]].
auto* return_method = inner_result_or_error.release_value();
// b. If return is undefined, return Completion(completion).
if (!return_method)
return restore_completion(); // If return is undefined, return Completion(completion).
return completion;
vm.stop_unwind();
// c. Set innerResult to Call(return, iterator).
auto result_or_error = vm.call(*return_method, &iterator);
if (result_or_error.is_error())
return_method_or_error = result_or_error.release_error();
inner_result_or_error = result_or_error.release_error();
else
result = result_or_error.release_value();
inner_result = result_or_error.release_value();
}
if (completion_exception)
return restore_completion(); // If completion.[[Type]] is throw, return Completion(completion).
if (return_method_or_error.is_error())
return; // If innerResult.[[Type]] is throw, return Completion(innerResult).
if (!result.is_object()) {
vm.throw_exception<TypeError>(global_object, ErrorType::IterableReturnBadReturn);
return; // If Type(innerResult.[[Value]]) is not Object, throw a TypeError exception.
}
restore_completion(); // Return Completion(completion).
// 5. If completion.[[Type]] is throw, return Completion(completion).
if (completion.is_error())
return completion;
// 6. If innerResult.[[Type]] is throw, return Completion(innerResult).
if (inner_result_or_error.is_error())
return inner_result_or_error.release_error();
// 7. If Type(innerResult.[[Value]]) is not Object, throw a TypeError exception.
if (!inner_result.is_object())
return vm.throw_completion<TypeError>(global_object, ErrorType::IterableReturnBadReturn);
// 8. Return Completion(completion).
return completion;
}
// 7.4.8 CreateIterResultObject ( value, done ), https://tc39.es/ecma262/#sec-createiterresultobject
@ -165,10 +173,8 @@ Completion get_iterator_values(GlobalObject& global_object, Value iterable, Iter
auto next_value = TRY(iterator_value(global_object, *next_object));
if (auto completion = callback(next_value); completion.has_value()) {
iterator_close(*iterator);
return completion.release_value();
}
if (auto completion = callback(next_value); completion.has_value())
return iterator_close(*iterator, completion.release_value());
}
}