Keeps the return type consistent with the function name. While we're at
it, we can also reduce the amount of boilerplate involved with handling
these by using structured bindings.
With this, all kernel objects finally have all of their data members
behind an interface, making it nicer to reason about interactions with
other code (as external code no longer has the freedom to totally alter
internals and potentially messing up invariants).
As means to pave the way for getting rid of global state within core,
This eliminates kernel global state by removing all globals. Instead
this introduces a KernelCore class which acts as a kernel instance. This
instance lives in the System class, which keeps its lifetime contained
to the lifetime of the System class.
This also forces the kernel types to actually interact with the main
kernel instance itself instead of having transient kernel state placed
all over several translation units, keeping everything together. It also
has a nice consequence of making dependencies much more explicit.
This also makes our initialization a tad bit more correct. Previously we
were creating a kernel process before the actual kernel was initialized,
which doesn't really make much sense.
The KernelCore class itself follows the PImpl idiom, which allows
keeping all the implementation details sealed away from everything else,
which forces the use of the exposed API and allows us to avoid any
unnecessary inclusions within the main kernel header.
These members don't need to be entirely exposed, we can instead expose
an API to operate on them without directly needing to mutate them
We can also guard against overflow/API misuse this way as well, given
active_sessions is an unsigned value.
General moving to keep kernel object types separate from the direct
kernel code. Also essentially a preliminary cleanup before eliminating
global kernel state in the kernel code.
This allows attaching a HLE handle to a ServerPort at any point after it
is created, allowing port/session creation to be generic between HLE and
regular services.
Sessions and Ports are now detached from each other.
HLE services are handled by means of a SessionRequestHandler class, Interface now inherits from this class.
The File and Directory classes are no longer kernel objects, but SessionRequestHandlers instead, bound to a ServerSession when requested.
File::OpenLinkFile now creates a new session pair and binds the File instance to it.
All handles obtained via srv::GetServiceHandle or svcConnectToPort are references to ClientSessions.
Service modules will wait on the counterpart of those ClientSessions (Called ServerSessions) using svcReplyAndReceive or svcWaitSynchronization[1|N], and will be awoken when a SyncRequest is performed.
HLE Interfaces are now ClientPorts which override the HandleSyncRequest virtual member function to perform command handling immediately.
