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LibJS: Construct ArrayBuffer with max byte length when provided

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ForLoveOfCats 2022-02-19 23:31:59 -05:00 • committed by Linus Groh
parent e8416b603f
commit e01ee4e30b
2 changed files with 22 additions and 6 deletions
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26
Userland/Libraries/LibJS/Runtime/ArrayBuffer.cpp
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@ -58,21 +58,35 @@ void ArrayBuffer::visit_edges(Cell::Visitor& visitor)
// 1.1.2 AllocateArrayBuffer ( constructor, byteLength [, maxByteLength ] ), https://tc39.es/proposal-resizablearraybuffer/#sec-allocatearraybuffer
ThrowCompletionOr<ArrayBuffer*> allocate_array_buffer(GlobalObject& global_object, FunctionObject& constructor, size_t byte_length, Optional<size_t> max_byte_length)
{
(void)max_byte_length;
// 1. Let obj be ? OrdinaryCreateFromConstructor(constructor, "%ArrayBuffer.prototype%", « [[ArrayBufferData]], [[ArrayBufferByteLength]], [[ArrayBufferDetachKey]] »).
// 1. Let slots be « [[ArrayBufferData]], [[ArrayBufferByteLength]], [[ArrayBufferDetachKey]] ».
// 2. If maxByteLength is present, append [[ArrayBufferMaxByteLength]] to slots.
// 3. Let obj be ? OrdinaryCreateFromConstructor(constructor, "%ArrayBuffer.prototype%", slots).
auto* obj = TRY(ordinary_create_from_constructor<ArrayBuffer>(global_object, constructor, &GlobalObject::array_buffer_prototype, nullptr));
// 2. Let block be ? CreateByteDataBlock(byteLength).
// 4. Let block be ? CreateByteDataBlock(byteLength).
auto block = ByteBuffer::create_zeroed(byte_length);
if (block.is_error())
return global_object.vm().throw_completion<RangeError>(global_object, ErrorType::NotEnoughMemoryToAllocate, byte_length);
// 3. Set obj.[[ArrayBufferData]] to block.
// 5. Set obj.[[ArrayBufferData]] to block.
obj->set_buffer(block.release_value());
// 4. Set obj.[[ArrayBufferByteLength]] to byteLength.
// 6. Set obj.[[ArrayBufferByteLength]] to byteLength.
// 5. Return obj.
// 7. If maxByteLength is present, then
if (max_byte_length.has_value()) {
// a. Assert: byteLength ≤ maxByteLength.
VERIFY(byte_length <= *max_byte_length);
// b. If it is not possible to create a Data Block block consisting of maxByteLength bytes, throw a RangeError exception.
// c. NOTE: Resizable ArrayBuffers are designed to be implementable with in-place growth. Implementations reserve the right to throw if, for example, virtual memory cannot be reserved up front.
// d. Set obj.[[ArrayBufferMaxByteLength]] to maxByteLength.
obj->set_max_byte_length(*max_byte_length);
}
// 8. Return obj.
return obj;
}