Localized file names and actual display names

Issue by pornel
Friday Jan 23, 2015 at 22:38 GMT

For earlier discussion, see https://github.com/rust-lang/rust/issues/21569

This issue was labelled with: A-io, A-libs, A-mac-osx in the Rust repository

In OS X you're not supposed to display POSIX paths to users. User-facing file names are supposed to use "display name" ([NSFilemanager displayNameAtPath:] and friends).

Rust's path.display() and Display guidelines sound like they're exactly for this purpose, but unfortunately path.display() falls short on OS X and probably can't be fixed without breaking at least some Cargo build scripts.

However, in OS X "display path" is seriously only for display and it's a one-way function:

[fm displayNameAtPath:@"/Applications"] == @"アプリケーション"; // If Japanese locale is set
[fm displayNameAtPath:@"foo:bar"] == @"foo/bar"; // Yes, Finder allows slashes in file names

I'd be lovely if Rust had built-in support for this and encouraged doing the right thing on OS X and other OSes that have localized paths.

Suggestions:

• Add path.filename_localized() and path.components_localized()
• Drop path.filename_display()
• Rename path.display() to path.to_string_lossy(), to make it clear that a code like println!("cargo:root={}", path.display()); is slightly buggy.
• Add format_bytes!() to make it easier to correctly format commandline arguments with paths.

Start with the earlier discussion in rust-lang/rust#21569 and the linked NSFileManager displayNameAtPath documentation, then compare them with Rust's path.display() and Display guidelines. Done means the scope for localized and display path APIs is decided, including the proposed formatting behavior and platform implications.