third_party/rust_crates/vendor/rouille/src/find_route.rs

// Copyright (c) 2016 The Rouille developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

/// Evaluates each parameter until one of them evaluates to something else
/// than a 404 error code.
///
/// This macro supposes that each route returns a `Response`.
///
/// # Example
///
/// ```
/// # #[macro_use] extern crate rouille;
/// # fn main() {
/// use rouille::{Request, Response};
///
/// fn handle_request_a(_: &Request) -> Response {
/// # panic!()
///    // ...
/// }
///
/// fn handle_request_b(_: &Request) -> Response {
/// # panic!()
///    // ...
/// }
///
/// fn handle_request_c(_: &Request) -> Response {
/// # panic!()
///    // ...
/// }
///
/// # let request = return;
/// // First calls `handle_request_a`. If it returns anything else than a 404 error, then the
/// // `response` will contain the return value.
/// //
/// // Instead if `handle_request_a` returned a 404 error, then `handle_request_b` is tried.
/// // If `handle_request_b` also returns a 404 error, then `handle_request_c` is tried.
/// let response = find_route!(
///     handle_request_a(request),
///     handle_request_b(request),
///     handle_request_c(request)
/// );
/// # }
/// ```
///
#[macro_export]
macro_rules! find_route {
    ($($handler:expr),+) => ({
        let mut response = $crate::Response::empty_404();
        $(
            if response.status_code == 404 {
                response = $handler;
            }
        )+
        response
    });
}