Enum Settings 

pub enum Settings {
    Files(Files),
}

The layers this platform actually keeps, and where it keeps them.

One type rather than a trait object, because the two implementations are the whole set. A platform keeps its policy in files or in a registry, this enum is those two, and for_this_platform is the only thing that builds one. A Box<dyn Source> would buy extensibility nobody wants and lose locations, which is not on Source deliberately — reading a layer and naming where it came from are different questions, and only the interface asks the second.

Variants

Files(Files)

Files at paths, which is Linux and the tests.

Implementations

impl Settings

pub fn locations(&self) -> Vec<(Origin, String)>

Where this machine reads its layers from, most authoritative first, in whatever words a person would use to go and look.

A path on one platform and a key on another, so the answer is a string rather than a Path: concept 10’s point is that only the running program can say where its settings are, and a type that can only hold filenames cannot say it on Windows.

Trait Implementations

impl Clone for Settings

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Settings

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Source for Settings

fn layer(&self, origin: Origin) -> Read

This layer, read now rather than remembered. An implementation that caches is the bypass concept 10 warns about.