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

// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// OpenEthereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with OpenEthereum.  If not, see <http://www.gnu.org/licenses/>.

use jsonrpc_core::{
    futures::{self, sync::oneshot, Future},
    Error,
};
use v1::helpers::errors;

pub type Res<T> = Result<T, Error>;

pub struct Sender<T> {
    sender: oneshot::Sender<Res<T>>,
}

impl<T> Sender<T> {
    pub fn send(self, data: Res<T>) {
        let res = self.sender.send(data);
        if res.is_err() {
            debug!(target: "rpc", "Responding to a no longer active request.");
        }
    }
}

pub struct Receiver<T> {
    receiver: oneshot::Receiver<Res<T>>,
}

impl<T> Future for Receiver<T> {
    type Item = T;
    type Error = Error;

    fn poll(&mut self) -> futures::Poll<Self::Item, Self::Error> {
        let res = self.receiver.poll();
        match res {
            Ok(futures::Async::NotReady) => Ok(futures::Async::NotReady),
            Ok(futures::Async::Ready(Ok(res))) => Ok(futures::Async::Ready(res)),
            Ok(futures::Async::Ready(Err(err))) => Err(err),
            Err(e) => {
                debug!(target: "rpc", "Responding to a canceled request: {:?}", e);
                Err(errors::internal("Request was canceled by client.", e))
            }
        }
    }
}

pub fn oneshot<T>() -> (Sender<T>, Receiver<T>) {
    let (tx, rx) = futures::oneshot();

    (Sender { sender: tx }, Receiver { receiver: rx })
}