Do this by:
- Removing more instances of `LockRefPtr` and `NonnullLockRefPtr`.
- Using better names of construction methods (i.e. `create` instead of
`try_create`).
- Only returning `NonnullRefPtr` on the `Device::try_create_device`
method.
- Removing a version of the `Device::try_create_device` method that
called `DeviceType::try_create(forward<Args>(args)...)`, which was
only used in a construction point in a VirtIO driver which now doesn't
need this anymore.
This change has many improvements:
- We don't use `LockRefPtr` to hold instances of many base devices as
with the DeviceManagement class. Instead, we have a saner pattern of
holding them in a `NonnullRefPtr<T> const`, in a small-text footprint
class definition in the `Device.cpp` file.
- The awkwardness of using `::the()` each time we need to get references
to mostly-static objects (like the Event queue) in runtime is now gone
in the migration to using the `Device` class.
- Acquiring a device feel more obvious because we use now the Device
class for this method. The method name is improved as well.
We used to allocate major numbers quite randomly, with no common place
to look them up if needed.
This commit is changing that by placing all major number allocations
under a new C++ namespace, in the API/MajorNumberAllocation.h file.
We also add the foundations of what is needed before we can publish this
information (allocated numbers for block and char devices) to userspace.
This device is a block device that allows a user to effectively treat an
Inode as a block device.
The static construction method is given an OpenFileDescription reference
but validates that:
- The description has a valid custody (so it's not some arbitrary file).
Failing this requirement will yield EINVAL.
- The description custody points to an Inode which is a regular file, as
we only support (seekable) regular files. Failing this requirement
will yield ENOTSUP.
LoopDevice can be used to mount a regular file on the filesystem like
other supported types of (physical) block devices.
