Android Download folder files get the wrong filenames on Android 13

[hrydgard]

When clicking Load... the content URI returned doesn't preserve the actual filename of the file being opened, instead what we get is like:

content://com.android.providers.downloads.documents/document/msf%3A10000000006

This is a problem because we rely on the filename a lot in file format detection, so you can't load elfs that way for example, let's say you download cube.elf from https://www.ppsspp.org/legacybuilds/ for example.

Two ways of fixing it:

• Go query the actual filename and get the extension separately. This complicates our internal storage API quite a bit.
• Change our file format detection to actually look more at bytes if there's no extension. Probably the easier option though for 1.15.4 I'll limit it to only do this check ELF, ISO, and CSO.
  • Actually, we partially already do this. I'll make it a little bit more complete.

[hrydgard]

Alright, turns out I misdiagnosed the problem. This is what we're getting:

05-15 19:54:13.947 30543 30762 I PPSSPP : [COMMON] Android_OpenContentUriFd: content://com.android.providers.downloads.documents/document/msf%3A1000000006%2F1000000006 (READ)
05-15 19:54:13.949 30543 30762 E PpssppActivity: openContentUri exception: java.lang.SecurityException: Permission Denial: reading com.android.providers.downloads.DownloadStorageProvider uri content://com.android.providers.downloads.documents/document/msf%3A1000000006%2F1000000006 from pid=30543, uid=10333 requires that you obtain access using ACTION_OPEN_DOCUMENT or related APIs

But, we did get the path through ACTION_OPEN_DOCUMENT? Anyway, we can detect this and put up an appropriate error message, at least...

No actually, there seems to be some double-concatenation of the filename here: msf%3A1000000006%2F1000000006 ...