Crate object_provider

Trait for requesting values by type from a given object.

Examples

Using a Provider

let provider: &dyn ObjectProvider;

// It's possible to request concrete types like `PathBuf`
let path_buf = provider.request::<PathBuf>().unwrap();
assert_eq!(path_buf, my_path);

// Requesting `!Sized` types, like slices and trait objects, is also supported.
let path = provider.request::<Path>().unwrap();
assert_eq!(path, my_path);

let debug = provider.request::<dyn Debug>().unwrap();
assert_eq!(
    format!("{:?}", debug),
    format!("{:?}", my_path),
);

// Types or interfaces not explicitly provided return `None`.
assert!(provider.request::<i32>().is_none());
assert!(provider.request::<dyn AsRef<Path>>().is_none());

Implementing a Provider

struct MyProvider {
    path: PathBuf,
}

impl ObjectProvider for MyProvider {
    fn provide<'r, 'a>(&'a self, request: Request<'r, 'a>) -> ProvideResult<'r, 'a> {
        request
            .provide::<PathBuf>(&self.path)?
            .provide::<Path>(&self.path)?
            .provide::<dyn Debug>(&self.path)
    }
}

Structs

FulfilledRequest	Marker type indicating a request has been fulfilled.
Request	A dynamic request for an object based on its type.

Traits

ObjectProvider	Trait to provide other objects based on a requested type at runtime.
ObjectProviderExt	Methods supported by all ObjectProvider implementors.

Type Definitions

ProvideResult

Provider method return type.