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use crate::{
body::Body,
request::Request,
responder::{DynResponder, Responder},
};
use futures::{future::BoxFuture, FutureExt};
use futures_util::future::Future;
pub trait Guard {
type Future: Future<Output = Result<Request<Body>, Self::Responder>> + Send;
type Responder: Responder + Send;
fn validate(&'static self, req: Request<Body>) -> Self::Future;
}
impl<Fun, Fut, Resp> Guard for Fun
where
Resp: Responder + Send,
Fun: Fn(Request<Body>) -> Fut,
Fut: 'static + Future<Output = Result<Request<Body>, Resp>> + Send,
{
type Future = BoxFuture<'static, Result<Request<Body>, Self::Responder>>;
type Responder = Resp;
#[inline]
fn validate(&self, req: Request<Body>) -> Self::Future {
(*self)(req).boxed()
}
}
pub struct Builder<Chain: GuardChain> {
chain: Chain,
}
impl Default for Builder<GuardChainEnd> {
fn default() -> Self {
Self { chain: GuardChainEnd }
}
}
impl<Chain: GuardChain + 'static> Builder<Chain> {
pub fn apply<Handler>(self, handler: Handler) -> Builder<GuardChainLink<Handler, Chain>>
where
Handler: 'static + Guard + Sync + Send,
{
Builder {
chain: GuardChainLink { handler, rest: self.chain },
}
}
pub(crate) fn build(self) -> Box<dyn GuardChain> {
Box::new(self.chain)
}
}
#[doc(hidden)]
pub trait GuardChain: Sync + Send {
fn validate(&'static self, req: Request<Body>) -> BoxFuture<'static, Result<Request<Body>, Box<dyn DynResponder + Send>>>;
fn is_end(&self) -> bool;
}
#[doc(hidden)]
pub struct GuardChainEnd;
impl GuardChain for GuardChainEnd {
#[inline]
fn validate(&'static self, req: Request<Body>) -> BoxFuture<'static, Result<Request<Body>, Box<dyn DynResponder + Send>>> {
async { Ok(req) }.boxed()
}
#[inline]
fn is_end(&self) -> bool {
true
}
}
#[doc(hidden)]
pub struct GuardChainLink<Handler: Guard, Rest: GuardChain> {
handler: Handler,
rest: Rest,
}
impl<Handler, Rest> GuardChain for GuardChainLink<Handler, Rest>
where
Handler: Guard + Sync + Send + 'static,
Rest: GuardChain + 'static,
{
#[inline]
fn validate(&'static self, req: Request<Body>) -> BoxFuture<'static, Result<Request<Body>, Box<dyn DynResponder + Send>>> {
async move {
match self.handler.validate(req).await {
Ok(req) => {
if self.rest.is_end() {
Ok(req)
} else {
self.rest.validate(req).await
}
}
Err(resp) => Err(Box::new(Some(resp)) as Box<dyn DynResponder + Send>),
}
}
.boxed()
}
#[inline]
fn is_end(&self) -> bool {
false
}
}