Function normalize_capability_path 

pub fn normalize_capability_path(path: &str) -> Option<PathBuf>

Lexically normalize an absolute capability path for allow-list matching.

Resolves . and .. components purely textually (no filesystem access, so it works for not-yet-created write targets) and collapses redundant separators. The result is the canonical lexical form a loader should match against a Capability::Filesystem allow-list and then act on.

Returns None when the path is unsafe to admit:

• it is relative (capability paths must be absolute), or
• a .. component would escape above the filesystem root, or
• it contains a platform prefix (e.g. a Windows drive prefix), which the capability model does not model.

A .. that stays within the root is resolved, not rejected — e.g. /data/../etc normalizes to /etc; admitting it here is safe because the allow-list match then rejects /etc for a /data/** grant. Only true root escapes are refused outright.

Examples

use std::path::PathBuf;
use uni_plugin::normalize_capability_path as norm;

assert_eq!(norm("/data/./sub/f"), Some(PathBuf::from("/data/sub/f")));
assert_eq!(norm("/data/../etc"), Some(PathBuf::from("/etc")));
assert_eq!(norm("/data/../../etc/passwd"), None); // escapes above root
assert_eq!(norm("data/x"), None); // relative