Advantages:
* Simpler code in general
* No extra volume objects created
* Now actually notices if the disc or partition gets
changed while the core is running
* No longer picks up on disc access done by the GUI
(it used to do so as long as the core was running)
* Gets rid of a Core dependency in DiscIO
There are two performance disadvantages:
* FileMonitor is now a bit slower when used with VolumeDirectory
because FileMonitor now always uses the FileSystemGCWii code
for finding filenames instead of VolumeDirectory finding the
filename on its own and directly hooking into FileMonitor.
But this isn't such a big deal, because it's happening on the
DVD thread, and my currently unmerged file system PR will make
FileSystemGCWii's file finding code about as fast as
VolumeDirectory's.
* FileMonitor's creation of the file system object is now
done on the CPU thread instead of the DVD thread, and
it will be done even if FileMonitor logging is disabled.
This will be fixed in the next commit.
s_dvd_thread_done_working makes the logic more complicated,
and degasus pointed out a race condition that can happen if
the CPU thread calls WaitForIdle right in between the DVD
thread executing done_working.Set() and done_working.Reset()
while there is work left to do. To avoid this, let's just get
rid of s_dvd_thread_done_working. It's a relic from the old
DVDThread design. Thanks to the last few commits, WaitUntilIdle
only gets called rarely (disc change and savestate), so it's
not a problem if WaitUntilIdle ends up being slower.
This is a preparation for adding a queue to DVDThread.
Currently, s_read_request and s_read_result act somewhat like
queues that only can contain one object.
JosJuice