1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
use super::FromEmptyRouter;
use crate::body::BoxBody;
use futures_util::ready;
use http::{Request, Response};
use pin_project_lite::pin_project;
use std::{
future::Future,
pin::Pin,
task::{Context, Poll},
};
use tower::{util::Oneshot, ServiceExt};
use tower_service::Service;
#[derive(Debug, Clone, Copy)]
pub struct Or<A, B> {
pub(super) first: A,
pub(super) second: B,
}
#[allow(warnings)]
impl<A, B, ReqBody> Service<Request<ReqBody>> for Or<A, B>
where
A: Service<Request<ReqBody>, Response = Response<BoxBody>> + Clone,
B: Service<Request<ReqBody>, Response = Response<BoxBody>, Error = A::Error> + Clone,
ReqBody: Send + Sync + 'static,
A: Send + 'static,
B: Send + 'static,
A::Future: Send + 'static,
B::Future: Send + 'static,
{
type Response = Response<BoxBody>;
type Error = A::Error;
type Future = ResponseFuture<A, B, ReqBody>;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Poll::Ready(Ok(()))
}
fn call(&mut self, mut req: Request<ReqBody>) -> Self::Future {
let original_uri = req.uri().clone();
ResponseFuture {
state: State::FirstFuture {
f: self.first.clone().oneshot(req),
},
second: Some(self.second.clone()),
original_uri: Some(original_uri),
}
}
}
pin_project! {
pub struct ResponseFuture<A, B, ReqBody>
where
A: Service<Request<ReqBody>>,
B: Service<Request<ReqBody>>,
{
#[pin]
state: State<A, B, ReqBody>,
second: Option<B>,
original_uri: Option<http::Uri>,
}
}
pin_project! {
#[project = StateProj]
enum State<A, B, ReqBody>
where
A: Service<Request<ReqBody>>,
B: Service<Request<ReqBody>>,
{
FirstFuture { #[pin] f: Oneshot<A, Request<ReqBody>> },
SecondFuture {
#[pin]
f: Oneshot<B, Request<ReqBody>>,
}
}
}
impl<A, B, ReqBody> Future for ResponseFuture<A, B, ReqBody>
where
A: Service<Request<ReqBody>, Response = Response<BoxBody>>,
B: Service<Request<ReqBody>, Response = Response<BoxBody>, Error = A::Error>,
ReqBody: Send + Sync + 'static,
{
type Output = Result<Response<BoxBody>, A::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
loop {
let mut this = self.as_mut().project();
let new_state = match this.state.as_mut().project() {
StateProj::FirstFuture { f } => {
let mut response = ready!(f.poll(cx)?);
let mut req = if let Some(ext) = response
.extensions_mut()
.remove::<FromEmptyRouter<ReqBody>>()
{
ext.request
} else {
return Poll::Ready(Ok(response));
};
*req.uri_mut() = this.original_uri.take().unwrap();
let second = this.second.take().expect("future polled after completion");
State::SecondFuture {
f: second.oneshot(req),
}
}
StateProj::SecondFuture { f } => return f.poll(cx),
};
this.state.set(new_state);
}
}
}