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LibJS: Implement missing steps from the ArrayBuffer transfer proposal

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We can now implement steps related to resizable ArrayBuffer objects. We
can also implement a couple of missing SharedArrayBuffer checks.

The original implementation of this proposal did not have any tests, so
tests are added here for the whole implementation.
This commit is contained in:
Timothy Flynn 2023-12-28 08:55:38 -05:00 • committed by Andreas Kling
parent 526a74f2f1
commit 3f3686cf7b
5 changed files with 201 additions and 8 deletions
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24
Userland/Libraries/LibJS/Runtime/ArrayBuffer.cpp
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@ -262,13 +262,15 @@ ThrowCompletionOr<Optional<size_t>> get_array_buffer_max_byte_length_option(VM&
}
// 25.1.2.14 ArrayBufferCopyAndDetach ( arrayBuffer, newLength, preserveResizability ), https://tc39.es/proposal-arraybuffer-transfer/#sec-arraybuffer.prototype.transfertofixedlength
ThrowCompletionOr<ArrayBuffer*> array_buffer_copy_and_detach(VM& vm, ArrayBuffer& array_buffer, Value new_length, PreserveResizability)
ThrowCompletionOr<ArrayBuffer*> array_buffer_copy_and_detach(VM& vm, ArrayBuffer& array_buffer, Value new_length, PreserveResizability preserve_resizability)
{
auto& realm = *vm.current_realm();
// 1. Perform ? RequireInternalSlot(arrayBuffer, [[ArrayBufferData]]).
// FIXME: 2. If IsSharedArrayBuffer(arrayBuffer) is true, throw a TypeError exception.
// 2. If IsSharedArrayBuffer(arrayBuffer) is true, throw a TypeError exception.
if (array_buffer.is_shared_array_buffer())
return vm.throw_completion<TypeError>(ErrorType::SharedArrayBuffer);
// 3. If newLength is undefined, then
// a. Let newByteLength be arrayBuffer.[[ArrayBufferByteLength]].
@ -280,17 +282,25 @@ ThrowCompletionOr<ArrayBuffer*> array_buffer_copy_and_detach(VM& vm, ArrayBuffer
if (array_buffer.is_detached())
return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
// FIXME: 6. If preserveResizability is preserve-resizability and IsResizableArrayBuffer(arrayBuffer) is true, then
// a. Let newMaxByteLength be arrayBuffer.[[ArrayBufferMaxByteLength]].
Optional<size_t> new_max_byte_length;
// 6. If preserveResizability is preserve-resizability and IsResizableArrayBuffer(arrayBuffer) is true, then
// FIXME: The ArrayBuffer transfer spec is a bit out-of-date. IsResizableArrayBuffer no longer exists, we now have IsFixedLengthArrayBuffer.
if (preserve_resizability == PreserveResizability::PreserveResizability && !array_buffer.is_fixed_length()) {
// a. Let newMaxByteLength be arrayBuffer.[[ArrayBufferMaxByteLength]].
new_max_byte_length = array_buffer.max_byte_length();
}
// 7. Else,
// a. Let newMaxByteLength be empty.
else {
// a. Let newMaxByteLength be empty.
}
// 8. If arrayBuffer.[[ArrayBufferDetachKey]] is not undefined, throw a TypeError exception.
if (!array_buffer.detach_key().is_undefined())
return vm.throw_completion<TypeError>(ErrorType::DetachKeyMismatch, array_buffer.detach_key(), js_undefined());
// 9. Let newBuffer be ? AllocateArrayBuffer(%ArrayBuffer%, newByteLength, FIXME: newMaxByteLength).
auto* new_buffer = TRY(allocate_array_buffer(vm, realm.intrinsics().array_buffer_constructor(), new_byte_length));
// 9. Let newBuffer be ? AllocateArrayBuffer(%ArrayBuffer%, newByteLength, newMaxByteLength).
auto* new_buffer = TRY(allocate_array_buffer(vm, realm.intrinsics().array_buffer_constructor(), new_byte_length, new_max_byte_length));
// 10. Let copyLength be min(newByteLength, arrayBuffer.[[ArrayBufferByteLength]]).
auto copy_length = min(new_byte_length, array_buffer.byte_length());