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/*
* Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/FunctionObject.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/IteratorOperations.h>
#include <LibJS/Runtime/TemporaryClearException.h>
namespace JS {
// 7.4.1 GetIterator ( obj [ , hint [ , method ] ] ), https://tc39.es/ecma262/#sec-getiterator
ThrowCompletionOr<Object*> get_iterator(GlobalObject& global_object, Value value, IteratorHint hint, Value method)
{
auto& vm = global_object.vm();
if (method.is_empty()) {
if (hint == IteratorHint::Async)
TODO();
method = TRY(value.get_method(global_object, *vm.well_known_symbol_iterator()));
}
if (!method.is_function())
return vm.throw_completion<TypeError>(global_object, ErrorType::NotIterable, value.to_string_without_side_effects());
auto iterator = TRY(vm.call(method.as_function(), value));
if (!iterator.is_object())
return vm.throw_completion<TypeError>(global_object, ErrorType::NotIterable, value.to_string_without_side_effects());
return &iterator.as_object();
}
// 7.4.2 IteratorNext ( iteratorRecord [ , value ] ), https://tc39.es/ecma262/#sec-iteratornext
ThrowCompletionOr<Object*> iterator_next(Object& iterator, Value value)
{
// FIXME: Implement using iterator records, not ordinary objects
auto& vm = iterator.vm();
auto& global_object = iterator.global_object();
auto next_method = TRY(iterator.get(vm.names.next));
if (!next_method.is_function())
return vm.throw_completion<TypeError>(global_object, ErrorType::IterableNextNotAFunction);
Value result;
if (value.is_empty())
result = TRY(vm.call(next_method.as_function(), &iterator));
else
result = TRY(vm.call(next_method.as_function(), &iterator, value));
if (!result.is_object())
return vm.throw_completion<TypeError>(global_object, ErrorType::IterableNextBadReturn);
return &result.as_object();
}
// 7.4.3 IteratorComplete ( iterResult ), https://tc39.es/ecma262/#sec-iteratorcomplete
ThrowCompletionOr<bool> iterator_complete(GlobalObject& global_object, Object& iterator_result)
{
auto& vm = global_object.vm();
// 1. Return ! ToBoolean(? Get(iterResult, "done")).
return TRY(iterator_result.get(vm.names.done)).to_boolean();
}
// 7.4.4 IteratorValue ( iterResult ), https://tc39.es/ecma262/#sec-iteratorvalue
ThrowCompletionOr<Value> iterator_value(GlobalObject& global_object, Object& iterator_result)
{
auto& vm = global_object.vm();
// 1. Return ? Get(iterResult, "value").
return TRY(iterator_result.get(vm.names.value));
}
// 7.4.5 IteratorStep ( iteratorRecord ), https://tc39.es/ecma262/#sec-iteratorstep
ThrowCompletionOr<Object*> iterator_step(GlobalObject& global_object, Object& iterator)
{
auto* result = TRY(iterator_next(iterator));
auto done = TRY(iterator_complete(global_object, *result));
if (done)
return nullptr;
return result;
}
// 7.4.6 IteratorClose ( iteratorRecord, completion ), https://tc39.es/ecma262/#sec-iteratorclose
Completion iterator_close(Object& iterator, Completion completion)
{
auto& vm = iterator.vm();
auto& global_object = iterator.global_object();
// The callers of iterator_close() are often in an exceptional state.
// Temporarily clear that exception for invocation(s) to Call.
TemporaryClearException clear_exception(vm);
// 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 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())
inner_result_or_error = result_or_error.release_error();
else
inner_result = result_or_error.release_value();
}
// 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
Object* create_iterator_result_object(GlobalObject& global_object, Value value, bool done)
{
auto& vm = global_object.vm();
auto* object = Object::create(global_object, global_object.object_prototype());
MUST(object->create_data_property_or_throw(vm.names.value, value));
MUST(object->create_data_property_or_throw(vm.names.done, Value(done)));
return object;
}
// 7.4.10 IterableToList ( items [ , method ] ), https://tc39.es/ecma262/#sec-iterabletolist
ThrowCompletionOr<MarkedValueList> iterable_to_list(GlobalObject& global_object, Value iterable, Value method)
{
auto& vm = global_object.vm();
MarkedValueList values(vm.heap());
TRY(get_iterator_values(
global_object, iterable, [&](auto value) -> Optional<Completion> {
values.append(value);
return {};
},
method));
return { move(values) };
}
Completion get_iterator_values(GlobalObject& global_object, Value iterable, IteratorValueCallback callback, Value method)
{
auto* iterator = TRY(get_iterator(global_object, iterable, IteratorHint::Sync, method));
while (true) {
auto* next_object = TRY(iterator_step(global_object, *iterator));
if (!next_object)
return {};
auto next_value = TRY(iterator_value(global_object, *next_object));
if (auto completion = callback(next_value); completion.has_value())
return iterator_close(*iterator, completion.release_value());
}
}
}
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