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/*
* Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/IteratorOperations.h>
namespace JS {
// 7.4.1 GetIterator ( obj [ , hint [ , method ] ] ), https://tc39.es/ecma262/#sec-getiterator
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();
auto object = value.to_object(global_object);
if (!object)
return {};
method = object->get(global_object.vm().well_known_symbol_iterator());
if (vm.exception())
return {};
}
if (!method.is_function()) {
vm.throw_exception<TypeError>(global_object, ErrorType::NotIterable, value.to_string_without_side_effects());
return nullptr;
}
auto iterator = vm.call(method.as_function(), value);
if (vm.exception())
return {};
if (!iterator.is_object()) {
vm.throw_exception<TypeError>(global_object, ErrorType::NotIterable, value.to_string_without_side_effects());
return nullptr;
}
return &iterator.as_object();
}
// 7.4.2 IteratorNext ( iteratorRecord [ , value ] ), https://tc39.es/ecma262/#sec-iteratornext
Object* iterator_next(Object& iterator, Value value)
{
auto& vm = iterator.vm();
auto& global_object = iterator.global_object();
auto next_method = iterator.get(vm.names.next);
if (vm.exception())
return {};
if (!next_method.is_function()) {
vm.throw_exception<TypeError>(global_object, ErrorType::IterableNextNotAFunction);
return nullptr;
}
Value result;
if (value.is_empty())
result = vm.call(next_method.as_function(), &iterator);
else
result = vm.call(next_method.as_function(), &iterator, value);
if (vm.exception())
return {};
if (!result.is_object()) {
vm.throw_exception<TypeError>(global_object, ErrorType::IterableNextBadReturn);
return nullptr;
}
return &result.as_object();
}
// 7.4.3 IteratorComplete ( iterResult ), https://tc39.es/ecma262/#sec-iteratorcomplete
bool iterator_complete(GlobalObject& global_object, Object& iterator_result)
{
return iterator_result.get(global_object.vm().names.done).value_or(Value(false)).to_boolean();
}
// 7.4.4 IteratorValue ( iterResult ), https://tc39.es/ecma262/#sec-iteratorvalue
Value iterator_value(GlobalObject& global_object, Object& iterator_result)
{
return iterator_result.get(global_object.vm().names.value).value_or(js_undefined());
}
// 7.4.6 IteratorClose ( iteratorRecord, completion ), https://tc39.es/ecma262/#sec-iteratorclose
void iterator_close(Object& iterator)
{
auto& vm = iterator.vm();
auto& global_object = iterator.global_object();
// Emulates `completion` behaviour
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);
};
auto return_method = get_method(global_object, &iterator, vm.names.return_);
if (!return_method)
return restore_completion(); // If return is undefined, return Completion(completion).
auto result = vm.call(*return_method, &iterator);
if (completion_exception)
return restore_completion(); // If completion.[[Type]] is throw, return Completion(completion).
if (vm.exception())
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).
}
// 7.4.8 CreateIterResultObject ( value, done ), https://tc39.es/ecma262/#sec-createiterresultobject
Value 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());
object->define_property(vm.names.value, value);
object->define_property(vm.names.done, Value(done));
return object;
}
// 7.4.10 IterableToList ( items [ , method ] ), https://tc39.es/ecma262/#sec-iterabletolist
MarkedValueList iterable_to_list(GlobalObject& global_object, Value iterable, Value method)
{
auto& vm = global_object.vm();
MarkedValueList values(vm.heap());
get_iterator_values(
global_object, iterable, [&](auto value) {
if (vm.exception())
return IterationDecision::Break;
values.append(value);
return IterationDecision::Continue;
},
method, CloseOnAbrupt::No);
return values;
}
void get_iterator_values(GlobalObject& global_object, Value value, AK::Function<IterationDecision(Value)> callback, Value method, CloseOnAbrupt close_on_abrupt)
{
auto& vm = global_object.vm();
auto iterator = get_iterator(global_object, value, IteratorHint::Sync, method);
if (!iterator)
return;
while (true) {
auto next_object = iterator_next(*iterator);
if (!next_object)
return;
auto done_property = next_object->get(vm.names.done);
if (vm.exception())
return;
if (!done_property.is_empty() && done_property.to_boolean())
return;
auto next_value = next_object->get(vm.names.value);
if (vm.exception())
return;
auto result = callback(next_value);
if (result == IterationDecision::Break) {
if (close_on_abrupt == CloseOnAbrupt::Yes)
iterator_close(*iterator);
return;
}
VERIFY(result == IterationDecision::Continue);
}
}
}
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