pezkuwichain
b6d35f6faf
Updated 4763 files with dual copyright: - Parity Technologies (UK) Ltd. - Dijital Kurdistan Tech Institute
122 lines
3.7 KiB
Rust
122 lines
3.7 KiB
Rust
// This file is part of Bizinikiwi.
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// Copyright (C) Parity Technologies (UK) Ltd. and Dijital Kurdistan Tech Institute
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// SPDX-License-Identifier: Apache-2.0
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//! Provides mpsc notification channel that can be instantiated
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//! _after_ it's been shared to the consumer and producers entities.
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//!
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//! Useful when building RPC extensions where, at service definition time, we
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//! don't know whether the specific interface where the RPC extension will be
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//! exposed is safe or not and we want to lazily build the RPC extension
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//! whenever we bind the service to an interface.
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//!
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//! See [`sc-service::builder::RpcExtensionBuilder`] for more details.
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use futures::stream::{FusedStream, Stream};
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use std::{
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pin::Pin,
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task::{Context, Poll},
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};
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use crate::pubsub::{Hub, Receiver};
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mod registry;
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use registry::Registry;
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#[cfg(test)]
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mod tests;
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/// Trait used to define the "tracing key" string used to tag
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/// and identify the mpsc channels.
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pub trait TracingKeyStr {
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/// Const `str` representing the "tracing key" used to tag and identify
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/// the mpsc channels owned by the object implementing this trait.
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const TRACING_KEY: &'static str;
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}
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/// The receiving half of the notifications channel.
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///
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/// The [`NotificationStream`] entity stores the [`Hub`] so it can be
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/// used to add more subscriptions.
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#[derive(Clone)]
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pub struct NotificationStream<Payload, TK: TracingKeyStr> {
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hub: Hub<Payload, Registry>,
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_pd: std::marker::PhantomData<TK>,
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}
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/// The receiving half of the notifications channel(s).
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#[derive(Debug)]
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pub struct NotificationReceiver<Payload> {
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receiver: Receiver<Payload, Registry>,
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}
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/// The sending half of the notifications channel(s).
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pub struct NotificationSender<Payload> {
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hub: Hub<Payload, Registry>,
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}
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impl<Payload, TK: TracingKeyStr> NotificationStream<Payload, TK> {
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/// Creates a new pair of receiver and sender of `Payload` notifications.
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pub fn channel() -> (NotificationSender<Payload>, Self) {
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let hub = Hub::new(TK::TRACING_KEY);
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let sender = NotificationSender { hub: hub.clone() };
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let receiver = NotificationStream { hub, _pd: Default::default() };
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(sender, receiver)
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}
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/// Subscribe to a channel through which the generic payload can be received.
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pub fn subscribe(&self, queue_size_warning: usize) -> NotificationReceiver<Payload> {
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let receiver = self.hub.subscribe((), queue_size_warning);
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NotificationReceiver { receiver }
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}
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}
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impl<Payload> NotificationSender<Payload> {
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/// Send out a notification to all subscribers that a new payload is available for a
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/// block.
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pub fn notify<Error>(
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&self,
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payload: impl FnOnce() -> Result<Payload, Error>,
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) -> Result<(), Error>
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where
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Payload: Clone,
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{
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self.hub.send(payload)
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}
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}
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impl<Payload> Clone for NotificationSender<Payload> {
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fn clone(&self) -> Self {
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Self { hub: self.hub.clone() }
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}
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}
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impl<Payload> Unpin for NotificationReceiver<Payload> {}
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impl<Payload> Stream for NotificationReceiver<Payload> {
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type Item = Payload;
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fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Payload>> {
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Pin::new(&mut self.get_mut().receiver).poll_next(cx)
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}
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}
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impl<Payload> FusedStream for NotificationReceiver<Payload> {
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fn is_terminated(&self) -> bool {
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self.receiver.is_terminated()
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}
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}
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