Rocket/examples/request_local_state/src/main.rs

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#![feature(plugin, decl_macro, never_type)]
#![plugin(rocket_codegen)]
extern crate rocket;
use std::sync::atomic::{AtomicUsize, Ordering};
use rocket::request::{self, Request, FromRequest, State};
use rocket::outcome::Outcome::*;
#[cfg(test)] mod tests;
#[derive(Default)]
struct Atomics {
uncached: AtomicUsize,
cached: AtomicUsize,
}
struct Guard1;
struct Guard2;
impl<'a, 'r> FromRequest<'a, 'r> for Guard1 {
type Error = ();
fn from_request(req: &'a Request<'r>) -> request::Outcome<Self, ()> {
let atomics = req.guard::<State<Atomics>>()?;
atomics.uncached.fetch_add(1, Ordering::Relaxed);
req.local_cache(|| atomics.cached.fetch_add(1, Ordering::Relaxed));
Success(Guard1)
}
}
impl<'a, 'r> FromRequest<'a, 'r> for Guard2 {
type Error = ();
fn from_request(req: &'a Request<'r>) -> request::Outcome<Self, ()> {
req.guard::<Guard1>()?;
Success(Guard2)
}
}
#[get("/")]
fn index(_g1: Guard1, _g2: Guard2) {
// This exists only to run the request guards.
}
fn rocket() -> rocket::Rocket {
rocket::ignite()
.manage(Atomics::default())
.mount("/", routes!(index))
}
fn main() {
rocket().launch();
}