This adds a formatter function for OwnPtr<KString>. This is added mainly
because lots of dbgln() statements generate Strings (such as absolute
paths) which are only used for debugging. Instead of catching possible
OOM situations at all the dbgln() callsites, this makes it possible to
let the formatter code handle those situations by outputting "[out of
memory]" if the OwnPtr is null.
This doesn't change anything because our global operator delete also
calls kfree() - however instead of relying on this implementation
detail this makes this dependency more explicit.
The user is supposed to hold these in an OwnPtr but bad things would
happen if the user takes these out of the OwnPtr so let's make the
class non-copyable and non-movable.
There are a bunch of places like drivers which for all intense and
purposes can't really fail allocation during boot, and if they do
fail we should crash immediately.
This change adds `KString::must_create_uninitialized(..)` as well as
`KString::must_create(..)` for use during early boot initialization of
the Kernel. They enforce that they are only used during early boot.
This is a simple string class for use in the kernel. It encapsulates
a length + character array in a single-allocation object.
Main differences from AK::String:
- Single-owner (no reference counting.)
- Allocation failures are exposed, not hidden.
The basic idea is to allow better and more precise string management
in the kernel.
