mirror of
https://github.com/pezkuwichain/pezkuwi-subxt.git
synced 2026-04-26 15:47:58 +00:00
André Silva
122 lines
3.7 KiB
Rust
122 lines
3.7 KiB
Rust
// This file is part of Substrate.
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// Copyright (C) 2017-2020 Parity Technologies (UK) Ltd.
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// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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use std::collections::HashMap;
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use std::sync::{Arc, atomic::{self, AtomicUsize}};
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use log::{error, warn};
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use jsonrpc_pubsub::{SubscriptionId, typed::{Sink, Subscriber}};
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use parking_lot::Mutex;
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use jsonrpc_core::futures::sync::oneshot;
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use jsonrpc_core::futures::{Future, future};
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type Id = u64;
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/// Alias for a an implementation of `futures::future::Executor`.
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pub type TaskExecutor = Arc<dyn future::Executor<Box<dyn Future<Item = (), Error = ()> + Send>> + Send + Sync>;
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/// Generate unique ids for subscriptions.
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#[derive(Clone, Debug)]
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pub struct IdProvider {
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next_id: Arc<AtomicUsize>,
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}
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impl Default for IdProvider {
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fn default() -> Self {
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IdProvider {
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next_id: Arc::new(AtomicUsize::new(1)),
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}
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}
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}
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impl IdProvider {
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/// Returns next id for the subscription.
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pub fn next_id(&self) -> Id {
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self.next_id.fetch_add(1, atomic::Ordering::AcqRel) as u64
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}
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}
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/// Subscriptions manager.
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///
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/// Takes care of assigning unique subscription ids and
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/// driving the sinks into completion.
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#[derive(Clone)]
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pub struct Subscriptions {
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next_id: IdProvider,
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active_subscriptions: Arc<Mutex<HashMap<Id, oneshot::Sender<()>>>>,
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executor: TaskExecutor,
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}
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impl Subscriptions {
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/// Creates new `Subscriptions` object.
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pub fn new(executor: TaskExecutor) -> Self {
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Subscriptions {
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next_id: Default::default(),
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active_subscriptions: Default::default(),
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executor,
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}
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}
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/// Borrows the internal task executor.
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///
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/// This can be used to spawn additional tasks on the underlying event loop.
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pub fn executor(&self) -> &TaskExecutor {
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&self.executor
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}
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/// Creates new subscription for given subscriber.
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///
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/// Second parameter is a function that converts Subscriber sink into a future.
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/// This future will be driven to completion by the underlying event loop
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/// or will be cancelled in case #cancel is invoked.
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pub fn add<T, E, G, R, F>(&self, subscriber: Subscriber<T, E>, into_future: G) -> SubscriptionId where
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G: FnOnce(Sink<T, E>) -> R,
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R: future::IntoFuture<Future=F, Item=(), Error=()>,
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F: future::Future<Item=(), Error=()> + Send + 'static,
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{
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let id = self.next_id.next_id();
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let subscription_id: SubscriptionId = id.into();
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if let Ok(sink) = subscriber.assign_id(subscription_id.clone()) {
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let (tx, rx) = oneshot::channel();
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let future = into_future(sink)
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.into_future()
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.select(rx.map_err(|e| warn!("Error timeing out: {:?}", e)))
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.then(|_| Ok(()));
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self.active_subscriptions.lock().insert(id, tx);
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if self.executor.execute(Box::new(future)).is_err() {
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error!("Failed to spawn RPC subscription task");
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}
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}
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subscription_id
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}
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/// Cancel subscription.
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///
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/// Returns true if subscription existed or false otherwise.
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pub fn cancel(&self, id: SubscriptionId) -> bool {
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if let SubscriptionId::Number(id) = id {
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if let Some(tx) = self.active_subscriptions.lock().remove(&id) {
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let _ = tx.send(());
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return true;
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}
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}
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false
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}
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}
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