Function component_dirs_from_dir 

fn component_dirs_from_dir(
    path: impl AsRef<Path>,
) -> Result<Vec<ComponentDir>, Error>

Creates a list of component directories from a directory.

Component directories may be those for OpenPGP User IDs or OpenPGP subkeys.

Errors

Returns an error if

• path is not a directory,
• an entry in path cannot be read,
• metadata for an entry in path cannot be retrieved,
• any path in path does not represent a directory,
• or any path in path cannot be turned into a ComponentDir.