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// This file is part of Substrate.
// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
// This program 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.
// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
use super::{config::Config, error::Error, request::Request};
use futures::{
channel::{mpsc, oneshot},
SinkExt,
};
use sp_core::Bytes;
use std::future::Future;
/// The other end of an [`Api`]. This should be passed to [`run`](super::run::run).
pub struct ApiBackend {
pub(super) request_receiver: mpsc::Receiver<Request>,
}
/// Interface to the mixnet service.
#[derive(Clone)]
pub struct Api {
request_sender: mpsc::Sender<Request>,
}
impl Api {
/// Create a new `Api`. The [`ApiBackend`] should be passed to [`run`](super::run::run).
pub fn new(config: &Config) -> (Self, ApiBackend) {
let (request_sender, request_receiver) = mpsc::channel(config.substrate.request_buffer);
(Self { request_sender }, ApiBackend { request_receiver })
}
/// Submit an extrinsic via the mixnet.
///
/// Returns a [`Future`] which returns another `Future`.
///
/// The first `Future` resolves as soon as there is space in the mixnet service queue. The
/// second `Future` resolves once a reply is received over the mixnet (or sooner if there is an
/// error).
///
/// The first `Future` references `self`, but the second does not. This makes it possible to
/// submit concurrent mixnet requests using a single `Api` instance.
pub async fn submit_extrinsic(
&mut self,
extrinsic: Bytes,
) -> impl Future<Output = Result<(), Error>> {
let (reply_sender, reply_receiver) = oneshot::channel();
let res = self
.request_sender
.feed(Request::SubmitExtrinsic { extrinsic, reply_sender })
.await;
async move {
res.map_err(|_| Error::ServiceUnavailable)?;
reply_receiver.await.map_err(|_| Error::ServiceUnavailable)?
}
}
}