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LibJS: Add spec comments to DataViewConstructor

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This commit is contained in:
Linus Groh 2023-01-27 21:36:31 +00:00
parent 0f3899b24a
commit 814e7260f3
1 changed files with 29 additions and 4 deletions
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33
Userland/Libraries/LibJS/Runtime/DataViewConstructor.cpp
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@ -34,6 +34,8 @@ void DataViewConstructor::initialize(Realm& realm)
ThrowCompletionOr<Value> DataViewConstructor::call()
{
auto& vm = this->vm();
// 1. If NewTarget is undefined, throw a TypeError exception.
return vm.throw_completion<TypeError>(ErrorType::ConstructorWithoutNew, vm.names.DataView);
}
@ -43,35 +45,58 @@ ThrowCompletionOr<NonnullGCPtr<Object>> DataViewConstructor::construct(FunctionO
auto& vm = this->vm();
auto buffer = vm.argument(0);
auto byte_offset = vm.argument(1);
auto byte_length = vm.argument(2);
// 2. Perform ? RequireInternalSlot(buffer, [[ArrayBufferData]]).
if (!buffer.is_object() || !is<ArrayBuffer>(buffer.as_object()))
return vm.throw_completion<TypeError>(ErrorType::IsNotAn, buffer.to_string_without_side_effects(), vm.names.ArrayBuffer);
auto& array_buffer = static_cast<ArrayBuffer&>(buffer.as_object());
auto offset = TRY(vm.argument(1).to_index(vm));
// 3. Let offset be ? ToIndex(byteOffset).
auto offset = TRY(byte_offset.to_index(vm));
// 4. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
if (array_buffer.is_detached())
return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
// 5. Let bufferByteLength be buffer.[[ArrayBufferByteLength]].
auto buffer_byte_length = array_buffer.byte_length();
// 6. If offset > bufferByteLength, throw a RangeError exception.
if (offset > buffer_byte_length)
return vm.throw_completion<RangeError>(ErrorType::DataViewOutOfRangeByteOffset, offset, buffer_byte_length);
size_t view_byte_length;
if (vm.argument(2).is_undefined()) {
// 7. If byteLength is undefined, then
if (byte_length.is_undefined()) {
// a. Let viewByteLength be bufferByteLength - offset.
view_byte_length = buffer_byte_length - offset;
} else {
view_byte_length = TRY(vm.argument(2).to_index(vm));
}
// 8. Else,
else {
// a. Let viewByteLength be ? ToIndex(byteLength).
view_byte_length = TRY(byte_length.to_index(vm));
// b. If offset + viewByteLength > bufferByteLength, throw a RangeError exception.
auto const checked_add = AK::make_checked(view_byte_length) + AK::make_checked(offset);
if (checked_add.has_overflow() || checked_add.value() > buffer_byte_length)
return vm.throw_completion<RangeError>(ErrorType::InvalidLength, vm.names.DataView);
}
// 9. Let O be ? OrdinaryCreateFromConstructor(NewTarget, "%DataView.prototype%", « [[DataView]], [[ViewedArrayBuffer]], [[ByteLength]], [[ByteOffset]] »).
// 11. Set O.[[ViewedArrayBuffer]] to buffer.
// 12. Set O.[[ByteLength]] to viewByteLength.
// 13. Set O.[[ByteOffset]] to offset.
auto data_view = TRY(ordinary_create_from_constructor<DataView>(vm, new_target, &Intrinsics::data_view_prototype, &array_buffer, view_byte_length, offset));
// 10. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
if (array_buffer.is_detached())
return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
// 14. Return O.
return data_view;
}