ladybird/Kernel/Devices/NullDevice.cpp
Andreas Kling 11eee67b85 Kernel: Make self-contained locking smart pointers their own classes
Until now, our kernel has reimplemented a number of AK classes to
provide automatic internal locking:

- RefPtr
- NonnullRefPtr
- WeakPtr
- Weakable

This patch renames the Kernel classes so that they can coexist with
the original AK classes:

- RefPtr => LockRefPtr
- NonnullRefPtr => NonnullLockRefPtr
- WeakPtr => LockWeakPtr
- Weakable => LockWeakable

The goal here is to eventually get rid of the Lock* classes in favor of
using external locking.
2022-08-20 17:20:43 +02:00

44 lines
1 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Singleton.h>
#include <Kernel/Devices/DeviceManagement.h>
#include <Kernel/Devices/NullDevice.h>
#include <Kernel/Sections.h>
namespace Kernel {
UNMAP_AFTER_INIT NonnullLockRefPtr<NullDevice> NullDevice::must_initialize()
{
auto null_device_or_error = DeviceManagement::try_create_device<NullDevice>();
// FIXME: Find a way to propagate errors
VERIFY(!null_device_or_error.is_error());
return null_device_or_error.release_value();
}
UNMAP_AFTER_INIT NullDevice::NullDevice()
: CharacterDevice(1, 3)
{
}
UNMAP_AFTER_INIT NullDevice::~NullDevice() = default;
bool NullDevice::can_read(OpenFileDescription const&, u64) const
{
return true;
}
ErrorOr<size_t> NullDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t)
{
return 0;
}
ErrorOr<size_t> NullDevice::write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t buffer_size)
{
return buffer_size;
}
}