RefPtr<ArrayBuffer> ArrayBuffer::sliceImpl(unsigned begin, unsigned end) const
{
unsigned size = begin <= end ? end - begin : 0;
RefPtr<ArrayBuffer> result = ArrayBuffer::create(static_cast<const char*>(data()) + begin, size);
result->setSharingMode(sharingMode());
return result;
}
static EncodedJSValue JSC_HOST_CALL constructArrayBuffer(ExecState* exec)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
JSArrayBufferConstructor* constructor =
jsCast<JSArrayBufferConstructor*>(exec->jsCallee());
unsigned length;
if (exec->argumentCount()) {
length = exec->uncheckedArgument(0).toIndex(exec, "length");
RETURN_IF_EXCEPTION(scope, encodedJSValue());
} else {
// Although the documentation doesn't say so, it is in fact correct to say
// "new ArrayBuffer()". The result is the same as allocating an array buffer
// with a zero length.
length = 0;
}
auto buffer = ArrayBuffer::tryCreate(length, 1);
if (!buffer)
return JSValue::encode(throwOutOfMemoryError(exec, scope));
if (constructor->sharingMode() == ArrayBufferSharingMode::Shared)
buffer->makeShared();
ASSERT(constructor->sharingMode() == buffer->sharingMode());
Structure* arrayBufferStructure = InternalFunction::createSubclassStructure(exec, exec->newTarget(), constructor->globalObject()->arrayBufferStructure(constructor->sharingMode()));
RETURN_IF_EXCEPTION(scope, encodedJSValue());
JSArrayBuffer* result = JSArrayBuffer::create(vm, arrayBufferStructure, WTFMove(buffer));
return JSValue::encode(result);
}
void ArrayBuffer::setSharingMode(ArrayBufferSharingMode newSharingMode)
{
if (newSharingMode == sharingMode())
return;
RELEASE_ASSERT(!isShared()); // Cannot revert sharing.
RELEASE_ASSERT(newSharingMode == ArrayBufferSharingMode::Shared);
makeShared();
}