This commit changes devices to always return IPCCommandResult rather
than just a return code for Open() and Close() in order to be able
to better emulate reply timing.
In hindsight, I should have considered we would want to emulate
timing when I cleaned up the device interface, but alas.
This rectifies that mistake.
I think I do not need to explain why hardcoding space usage for two
random directories when we can calculate it and when IOS doesn't
actually do that is wrong.
Some code was calling more than one of these functions in a row
(in particular, FileUtil.cpp itself did it a lot...), which is
a waste since it's possible to call stat a single time and then
read all three values from the stat struct. This commit adds a
File::FileInfo class that calls stat once on construction and
then lets Exists/IsDirectory/GetSize be executed very quickly.
The performance improvement mostly matters for functions that
can be handling a lot of files, such as File::ScanDirectoryTree.
I've also done some cleanup in code that uses these functions.
For instance, some code had checks like !Exists() || !IsDirectory(),
which is functionally equivalent to !IsDirectory(), and some
code was using File::GetSize even though there was an IOFile
object that the code could call GetSize on.
This changes the main IOS code (roughly the equivalent of the kernel)
to a class instead of being a set of free functions + tons of static
variables.
The reason for this change is that keeping tons of static variables
like that prevents us from making an IOS instance and reusing IOS
code easily.
Converting the IOS code to a class also allows us to mostly decouple
IOS from the PPC emulation.
The more interesting changes are in Core/IOS/IOS. Everything else is
mostly just boring stuff required by this change...
* Because the devices themselves call back to the main IOS code
for various things (getting the current version, replying to a
request, and other syscall-like functions), just like processes in
IOS call kernel syscalls, we have to pass a reference to the kernel
to anything that uses IOS syscalls.
* Change DoState to save device names instead of device IDs to simplify
AddDevice() and get rid of an ugly static count.
* Change ES_Launch's ack to be sent at IOS boot, now that we can do
this properly.
This changes the IOS code to handle ES contexts inside of ES, instead
of leaking out implementation details into the IPC request dispatcher.
The intent is to clarify what's shared between every single ES context,
and what is specific to an ES context. (Not much.) This should reduce
the number of static members in the ES class.
The other changes are there just because we now keep track of the
IPC FD inside of ES.
Future plans:
* After the WAD direct launch hack is dropped, the title context
will be made a class member.
* Have proper function prototypes, instead of having every single one
of them take ioctlv requests. This will allow reusing IOS code in
other parts of the Dolphin codebase without having to construct
ioctlv requests.
The /tmp directory is cleared every time IOS boots up (when the FS
driver is initialized), *not* when /dev/fs is opened.
Although this should have no effect, it fixes the case where files
could be left in /tmp and seen before opening /dev/fs.
Fixes a logic bug I introduced as part of #4942. We were not
handling the "read past EOF" case correctly, which caused
requested_read_length to underflow in some cases.
Also fixes a comparison (though this is unlikely to change anything).
This changes the read request handler to work just like IOS:
* To make things clearer, we now return early from error conditions,
instead of having nested ifs.
* IOS does an additional check on the requested read length, and
substracts the current seek position from it, if the read would
cause IOS to read past the EOF (not sure what the purpose of this
check is, but IOS does it, so we should too).
* The most significant one: IOS does *not* return the requested read
length, or update the file seek position with it. Instead, it uses
the *actual* read length.
As a result of simply doing what IOS does, this fixes _Mushroom Men_.
The game creates a save file, reads 2560 bytes from it, then
immediately writes 16384 bytes to it. With IOS, the first read does not
change the seek position at all, so the save data is written at
offset 0, not 2560. With Dolphin, the read erroneously set the
seek position to 2560, which caused the data to be written at
the wrong location.
Behavior confirmed by comparing IPC replies with IOS LLE and by looking
at the FS module in IOS.
We can return early from invalid conditions, which allows getting rid
of quite a few levels of indentation.
And let's not duplicate the new_position > file_size check.
IPC_HLE is actually IOS HLE. The actual IPC emulation is not in
IPC_HLE, but in HW/WII_IPC.cpp. So calling IPC_HLE IOS is more
accurate. (If IOS LLE gets ever implemented, it'll likely be at
a lower level -- Starlet LLE.)
This also totally gets rid of the IPC_HLE prefix in file names, and
moves some source files to their own subdirectories to make the file
hierarchy cleaner.
We're going to get ~14 additional source files with the USB PR,
and this is really needed to keep things from becoming a total pain.
