third_party/v8/src/builtins/arraybuffer.tq

// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

namespace arraybuffer {

// #sec-get-arraybuffer.prototype.bytelength
transitioning javascript builtin ArrayBufferPrototypeGetByteLength(
    js-implicit context: NativeContext, receiver: JSAny)(): Number {
  // 1. Let O be the this value.
  // 2. Perform ? RequireInternalSlot(O, [[ArrayBufferData]]).
  const o = Cast<JSArrayBuffer>(receiver) otherwise
  ThrowTypeError(
      MessageTemplate::kIncompatibleMethodReceiver,
      'get ArrayBuffer.prototype.byteLength', receiver);
  // 3. If IsSharedArrayBuffer(O) is true, throw a TypeError exception.
  if (IsSharedArrayBuffer(o)) {
    ThrowTypeError(
        MessageTemplate::kIncompatibleMethodReceiver,
        'get ArrayBuffer.prototype.byteLength', receiver);
  }
  // 4. If IsDetachedBuffer(O) is true, throw a TypeError exception.
  // TODO(v8:4895): We don't actually throw here.
  // 5. Let length be O.[[ArrayBufferByteLength]].
  const length = o.byte_length;
  // 6. Return length.
  return Convert<Number>(length);
}

// #sec-get-sharedarraybuffer.prototype.bytelength
transitioning javascript builtin SharedArrayBufferPrototypeGetByteLength(
    js-implicit context: NativeContext, receiver: JSAny)(): Number {
  // 1. Let O be the this value.
  // 2. Perform ? RequireInternalSlot(O, [[ArrayBufferData]]).
  const o = Cast<JSArrayBuffer>(receiver) otherwise
  ThrowTypeError(
      MessageTemplate::kIncompatibleMethodReceiver,
      'get SharedArrayBuffer.prototype.byteLength', receiver);
  // 3. If IsSharedArrayBuffer(O) is false, throw a TypeError exception.
  if (!IsSharedArrayBuffer(o)) {
    ThrowTypeError(
        MessageTemplate::kIncompatibleMethodReceiver,
        'get SharedArrayBuffer.prototype.byteLength', receiver);
  }
  // 4. Let length be O.[[ArrayBufferByteLength]].
  const length = o.byte_length;
  // 5. Return length.
  return Convert<Number>(length);
}

// #sec-arraybuffer.isview
transitioning javascript builtin ArrayBufferIsView(arg: JSAny): Boolean {
  // 1. If Type(arg) is not Object, return false.
  // 2. If arg has a [[ViewedArrayBuffer]] internal slot, return true.
  // 3. Return false.
  typeswitch (arg) {
    case (JSArrayBufferView): {
      return True;
    }
    case (JSAny): {
      return False;
    }
  }
}

}  // namespace arraybuffer