pub fn resolve_root(uid: u32, fallback: Option<PathBuf>) -> Option<PathBuf>Expand description
Resolve the cache root, or None when no safe location can be
established. Callers MUST treat None as a refusal rather than
substituting a guess: a shared world-writable fallback is what this
function exists to prevent.
Prefers $XDG_CACHE_HOME, then ~/.cache, both of which are already
user-private. Only an absolute env-derived path is trusted, because an
empty or relative one would resolve against the current directory, which
the caller does not control. fallback supplies the last resort (the
runtime passes its 0700 per-uid directory; a caller with none passes
None).