Trait ConsumingRequest

Source

pub trait ConsumingRequest {
    type Output;
    type Error;

    // Required method
    fn perform(self) -> Result<Self::Output, Self::Error>;
}

Expand description

A request that is consumed by performing it.

Implemented by crate::close::CloseRequest, where performing twice would mean closing a handle twice. The trait carries that property rather than leaving it to a comment.

§Example

use windows_namespace_request_sys::outcome::Outcome;
use windows_namespace_request_sys::request::ConsumingRequest;
use windows_namespace_request_sys::Win32Error;

// A consumer's cleanup step, written against the trait.
fn perform_all<R: ConsumingRequest>(requests: Vec<R>) -> usize {
    requests
        .into_iter()
        .filter(|_| true)
        .map(ConsumingRequest::perform)
        .filter(Result::is_ok)
        .count()
}

struct FakeClose;

impl ConsumingRequest for FakeClose {
    type Error = Win32Error;
    type Output = ();

    fn perform(self) -> Outcome<()> {
        Ok(())
    }
}

assert_eq!(perform_all(vec![FakeClose, FakeClose]), 2);