Make WiiSave::Import() behave closer to the Wii System Menu's SD Card save copying.

[AdmiralCurtiss]

In practice, this means:

• Saves are now only allowed to be imported if the game was previously 'seen' by ES. This includes launching it or even just inserting the game into the disc drive while the Wii Menu is running. Turns out this was previously the case too, but in a rather implicit fashion. This is now more explicit and works like the Wii Menu where it reinstalls a TMD if it's in the tmds.sys backup file. (which can happen if you had a save once and then delete it)
• Saves are now deleted before a new one is imported. This prevents a few potential oddities like ending up with mixed old and new files, or completely failing the import on saves with subdirectories.

Please scrutinize this, I'm not entirely sure if everything here is correct and makes sense.

[AdmiralCurtiss]

If it was already enforced then it either wasn't explicitly or it was somewhere other than the importing logic itself. I'll see if I can find it.

I agree that our UX of Wii NAND handling is very poor -- I would personally like to have a GCI folder-like approach where a temp NAND is build from scratch with the correct data when launching games from the game list, mostly to get rid of years of built-up cruft in many users' NANDs ranging from older Dolphin versions not handling stuff correctly to just plain user error that leads to very hard to diagnose (for users) issues. However, that is far outside the scope of this issue with how the Wii handles its saves.

[AdmiralCurtiss]

re: already-seen requirement, I checked and what happens in the old version is that this query here fails:

dolphin/Source/Core/Core/HW/WiiSave.cpp

Lines 203 to 210 in f45a4a5

	void InitTitleUidAndGid()
	{
	const auto metadata = m_fs->GetMetadata(IOS::PID_KERNEL, IOS::PID_KERNEL, m_data_dir);
	if (!metadata)
	return;
	m_uid = metadata->uid;
	m_gid = metadata->gid;
	}

Which then leads to the rest of the functions returning immediately cause they have no UID/GID. Yes, I suppose that is an enforcement, if not a very obvious one.

[Adamillo]

I don't know if this update caused this to happen or not but here's my theory: After I downloaded this update yesterday all the save data for my Wii games got WIPED! Maybe it's because of this update, or maybe not, but the fact is: Wii save data gone after I updated! Edit: Maybe the latest dev build of Dolphin doesn't know where my saves are stored or not lemme test that with beta.

[JMC47]

This just changes the save import function. If your saves somehow got wiped, it would have to be something else.

[Adamillo]

Still sad that my save data is gone :(

[JMC47]

Do you have any idea what happened to it? Obviously any time savedata gets removed is a problem. Do you know what builds you jumped between? Do you have the NANDs to see what's left in them?