On 7 Mar 2017, at 12:47, Jean-Daniel <mail...@xenonium.com> wrote: > > Did you try to use NSString -fileSystemRepresentation instead of UTF-8, or > even better, use URL. While using UTF-8 for path worked well on HFS+, It was > never guaranteed to work on all FS.
FWIW, the macOS kernel does use UTF-8 at the VFS interface (and therefore the BSD syscalls that take path arguments expect UTF-8). This is different to most other UNIXen (which tend to treat paths as a bunch of bytes, at least at syscall level and often at filesystem level too). It’s definitely the case that for the built-in FAT, NTFS and HFS+ implementations, UTF-8 will work. Other filesystem implementations really *should* be treating what they get as UTF-8 too, but obviously that’s not guaranteed. AFAIK all -fileSystemRepresentation does is it processes the Unicode string according to the rules in TN1150 and then convert to UTF-8; but you don’t actually *need* to do the HFS+ mapping (TN1150) before calling the BSD API (and it doesn’t even make any sense to do so unless the filesystem is HFS+, which -fileSystemRepresentation has no way of knowing). The main benefit is that the result will compare bytewise equal with a filename read from the filesystem (assuming HFS+). On other filesystems, well, things are different. VFAT and later variants store UTF-16, as does NTFS, but the rules in both cases differ. ExtFS, UFS et al. tend to regard filenames as a bunch of bytes and don’t even try to record what encoding was used. I don’t know what ZFS, XFS or JFS do; using Unicode at filesystem level on a UNIX-like system is not unproblematic (because it may very well *not* be the same encoding being used at the user’s terminal), but equally the bunch of bytes approach creates all kinds of fun (you may *see* a file with a particular name, but you can’t necessarily name it yourself from the keyboard...) Not that I’d recommend *not* using -fileSystemRepresentation; Apple says we should, so we should. I’m just observing that it isn’t a particularly good API and in future it’ll either be deprecated or do the exact same thing as -UTF8String because there’s really no other good option I can see. Kind regards, Alastair. -- http://alastairs-place.net _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
