openethereum/rpc/src/v1/helpers/subscribers.rs

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// Copyright 2015-2017 Parity Technologies (UK) Ltd.
// This file is part of Parity.
// Parity 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.
// Parity 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 Parity. If not, see <http://www.gnu.org/licenses/>.
//! A map of subscribers.
use std::{ops, str};
use std::collections::HashMap;
use jsonrpc_macros::pubsub::{Subscriber, Sink, SubscriptionId};
use rand::{Rng, StdRng};
use v1::types::H64;
#[derive(Debug, Clone, Hash, Eq, PartialEq)]
pub struct Id(H64);
impl str::FromStr for Id {
type Err = String;
fn from_str(s: &str) -> Result<Self, Self::Err> {
if s.starts_with("0x") {
Ok(Id(s[2..].parse().map_err(|e| format!("{}", e))?))
} else {
Err("The id must start with 0x".into())
}
}
}
impl Id {
pub fn as_string(&self) -> String {
format!("0x{:?}", self.0)
}
}
#[derive(Clone)]
pub struct Subscribers<T> {
rand: StdRng,
subscriptions: HashMap<Id, T>,
}
impl<T> Default for Subscribers<T> {
fn default() -> Self {
Subscribers {
rand: StdRng::new().expect("Valid random source is required."),
subscriptions: HashMap::new(),
}
}
}
impl<T> Subscribers<T> {
/// Create a new Subscribers with given random source.
#[cfg(test)]
pub fn new_test() -> Self {
Subscribers {
rand: ::rand::SeedableRng::from_seed([0usize].as_ref()),
subscriptions: HashMap::new(),
}
}
fn next_id(&mut self) -> Id {
let mut data = H64::default();
self.rand.fill_bytes(&mut data.0);
Id(data)
}
/// Insert new subscription and return assigned id.
pub fn insert(&mut self, val: T) -> SubscriptionId {
let id = self.next_id();
debug!(target: "pubsub", "Adding subscription id={:?}", id);
let s = id.as_string();
self.subscriptions.insert(id, val);
SubscriptionId::String(s)
}
/// Removes subscription with given id and returns it (if any).
pub fn remove(&mut self, id: &SubscriptionId) -> Option<T> {
trace!(target: "pubsub", "Removing subscription id={:?}", id);
match *id {
SubscriptionId::String(ref id) => match id.parse() {
Ok(id) => self.subscriptions.remove(&id),
Err(_) => None,
},
_ => None,
}
}
}
impl<T> Subscribers<Sink<T>> {
/// Assigns id and adds a subscriber to the list.
pub fn push(&mut self, sub: Subscriber<T>) {
let id = self.next_id();
if let Ok(sink) = sub.assign_id(SubscriptionId::String(id.as_string())) {
debug!(target: "pubsub", "Adding subscription id={:?}", id);
self.subscriptions.insert(id, sink);
}
}
}
impl<T, V> Subscribers<(Sink<T>, V)> {
/// Assigns id and adds a subscriber to the list.
pub fn push(&mut self, sub: Subscriber<T>, val: V) {
let id = self.next_id();
if let Ok(sink) = sub.assign_id(SubscriptionId::String(id.as_string())) {
debug!(target: "pubsub", "Adding subscription id={:?}", id);
self.subscriptions.insert(id, (sink, val));
}
}
}
impl<T> ops::Deref for Subscribers<T> {
type Target = HashMap<Id, T>;
fn deref(&self) -> &Self::Target {
&self.subscriptions
}
}