tower-grpc 0.1.1

A client and server gRPC implementation based on Tower.
Documentation 
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
130
131
132
133
134
135
136
137
138
139
140
141

use super::streaming;
use crate::generic::server::ServerStreamingService;
use crate::generic::{Encode, Encoder};
use crate::{Request, Response};

use futures::{try_ready, Future, Poll, Stream};
use std::fmt;

/// A server streaming response future
pub struct ResponseFuture<T, E, S>
where
    T: ServerStreamingService<S::Item>,
    S: Stream,
{
    inner: streaming::ResponseFuture<Inner<T, S>, E>,
}

struct Inner<T, S>
where
    T: ServerStreamingService<S::Item>,
    S: Stream,
{
    inner: T,
    state: Option<State<T::Future, S>>,
}

#[derive(Debug)]
enum State<T, S> {
    /// Waiting for the request to be received
    Requesting(Request<S>),

    /// Waiting for the response future to resolve
    Responding(T),
}

// ===== impl ResponseFuture ======

impl<T, E, S> ResponseFuture<T, E, S>
where
    T: ServerStreamingService<S::Item, Response = E::Item>,
    E: Encoder,
    S: Stream<Error = crate::Status>,
{
    pub fn new(inner: T, request: Request<S>, encoder: E) -> Self {
        let inner = Inner {
            inner,
            state: Some(State::Requesting(request)),
        };

        let inner = streaming::ResponseFuture::new(inner, encoder);
        ResponseFuture { inner }
    }
}

impl<T, E, S> Future for ResponseFuture<T, E, S>
where
    T: ServerStreamingService<S::Item, Response = E::Item>,
    E: Encoder,
    S: Stream<Error = crate::Status>,
{
    type Item = http::Response<Encode<E, T::ResponseStream>>;
    type Error = crate::error::Never;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        self.inner.poll()
    }
}

// ===== impl Inner =====

impl<T, S> Future for Inner<T, S>
where
    T: ServerStreamingService<S::Item>,
    S: Stream<Error = crate::Status>,
{
    type Item = Response<T::ResponseStream>;
    type Error = crate::Status;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        use self::State::*;

        loop {
            let msg = match *self.state.as_mut().unwrap() {
                Requesting(ref mut request) => try_ready!(request.get_mut().poll()),
                Responding(ref mut fut) => {
                    return fut.poll();
                }
            };

            match msg {
                Some(msg) => match self.state.take().unwrap() {
                    Requesting(request) => {
                        let request = request.map(|_| msg);
                        let response = self.inner.call(request);

                        self.state = Some(Responding(response));
                    }
                    _ => unreachable!(),
                },
                None => {
                    return Err(crate::Status::new(
                        crate::Code::Internal,
                        "Missing request message.",
                    ))
                }
            }
        }
    }
}

impl<T, E, S> fmt::Debug for ResponseFuture<T, E, S>
where
    T: ServerStreamingService<S::Item> + fmt::Debug,
    T::Response: fmt::Debug,
    T::ResponseStream: fmt::Debug,
    T::Future: fmt::Debug,
    E: fmt::Debug,
    S: Stream + fmt::Debug,
{
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_struct("server_streaming::ResponseFuture")
            .field("inner", &self.inner)
            .finish()
    }
}

impl<T, S> fmt::Debug for Inner<T, S>
where
    T: ServerStreamingService<S::Item> + fmt::Debug,
    T::Response: fmt::Debug,
    T::ResponseStream: fmt::Debug,
    T::Future: fmt::Debug,
    S: Stream + fmt::Debug,
{
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_struct("Inner")
            .field("inner", &self.inner)
            .field("state", &self.state)
            .finish()
    }
}