In a real 3DS, threads that call svcSyncRequest are put to sleep until the server responds via svcReplyAndReceive. Our HLE services don't implement this mechanism and are effectively immediate from the 3DS's point of view. This commit makes it so that we at least simulate the IPC delay.
Specific HLE handlers might need to put their callers to sleep for a longer period of time to simulate IO timings. This is their responsibility but doing so is currently not implemented.
See https://gist.github.com/ds84182/4a7690c5376e045cab9129ca4185bbeb for a test that was not passing before this commit.
The error code 0xC920181A will be returned by svcReplyAndReceive when the wakeup callback runs.
This lets LLE services be properly notified of clients closing the connection so they can end their handler threads instead of letting them linger indefinitely, taking up connection slots in their parent port.
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.
