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| 1 | +// This file is Copyright its original authors, visible in version control |
| 2 | +// history. |
| 3 | +// |
| 4 | +// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE |
| 5 | +// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| 6 | +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option. |
| 7 | +// You may not use this file except in accordance with one or both of these |
| 8 | +// licenses. |
| 9 | + |
| 10 | +//! Events are surfaced by the library to indicate some action must be taken |
| 11 | +//! by the end-user. |
| 12 | +//! |
| 13 | +//! Because we don't have a built-in runtime, it's up to the end-user to poll |
| 14 | +//! [`LiquidityManager::get_and_clear_pending_events`] to receive events. |
| 15 | +//! |
| 16 | +//! [`LiquidityManager::get_and_clear_pending_events`]: crate::LiquidityManager::get_and_clear_pending_events |
| 17 | +
|
| 18 | +use crate::lsps0; |
| 19 | +use crate::lsps1; |
| 20 | +use crate::lsps2; |
| 21 | +use crate::prelude::{Vec, VecDeque}; |
| 22 | +use crate::sync::{Arc, Mutex}; |
| 23 | + |
| 24 | +use core::future::Future; |
| 25 | +use core::task::{Poll, Waker}; |
| 26 | + |
| 27 | +pub(crate) struct EventQueue { |
| 28 | + queue: Arc<Mutex<VecDeque<Event>>>, |
| 29 | + waker: Arc<Mutex<Option<Waker>>>, |
| 30 | + #[cfg(feature = "std")] |
| 31 | + condvar: std::sync::Condvar, |
| 32 | +} |
| 33 | + |
| 34 | +impl EventQueue { |
| 35 | + pub fn new() -> Self { |
| 36 | + let queue = Arc::new(Mutex::new(VecDeque::new())); |
| 37 | + let waker = Arc::new(Mutex::new(None)); |
| 38 | + #[cfg(feature = "std")] |
| 39 | + { |
| 40 | + let condvar = std::sync::Condvar::new(); |
| 41 | + Self { queue, waker, condvar } |
| 42 | + } |
| 43 | + #[cfg(not(feature = "std"))] |
| 44 | + Self { queue, waker } |
| 45 | + } |
| 46 | + |
| 47 | + pub fn enqueue(&self, event: Event) { |
| 48 | + { |
| 49 | + let mut queue = self.queue.lock().unwrap(); |
| 50 | + queue.push_back(event); |
| 51 | + } |
| 52 | + |
| 53 | + if let Some(waker) = self.waker.lock().unwrap().take() { |
| 54 | + waker.wake(); |
| 55 | + } |
| 56 | + #[cfg(feature = "std")] |
| 57 | + self.condvar.notify_one(); |
| 58 | + } |
| 59 | + |
| 60 | + pub fn next_event(&self) -> Option<Event> { |
| 61 | + self.queue.lock().unwrap().pop_front() |
| 62 | + } |
| 63 | + |
| 64 | + pub async fn next_event_async(&self) -> Event { |
| 65 | + EventFuture { event_queue: Arc::clone(&self.queue), waker: Arc::clone(&self.waker) }.await |
| 66 | + } |
| 67 | + |
| 68 | + #[cfg(feature = "std")] |
| 69 | + pub fn wait_next_event(&self) -> Event { |
| 70 | + let mut queue = |
| 71 | + self.condvar.wait_while(self.queue.lock().unwrap(), |queue| queue.is_empty()).unwrap(); |
| 72 | + |
| 73 | + let event = queue.pop_front().expect("non-empty queue"); |
| 74 | + let should_notify = !queue.is_empty(); |
| 75 | + |
| 76 | + drop(queue); |
| 77 | + |
| 78 | + if should_notify { |
| 79 | + if let Some(waker) = self.waker.lock().unwrap().take() { |
| 80 | + waker.wake(); |
| 81 | + } |
| 82 | + |
| 83 | + self.condvar.notify_one(); |
| 84 | + } |
| 85 | + |
| 86 | + event |
| 87 | + } |
| 88 | + |
| 89 | + pub fn get_and_clear_pending_events(&self) -> Vec<Event> { |
| 90 | + self.queue.lock().unwrap().drain(..).collect() |
| 91 | + } |
| 92 | +} |
| 93 | + |
| 94 | +/// An event which you should probably take some action in response to. |
| 95 | +#[derive(Debug, Clone, PartialEq, Eq)] |
| 96 | +pub enum Event { |
| 97 | + /// An LSPS0 client event. |
| 98 | + LSPS0Client(lsps0::event::LSPS0ClientEvent), |
| 99 | + /// An LSPS1 (Channel Request) client event. |
| 100 | + LSPS1Client(lsps1::event::LSPS1ClientEvent), |
| 101 | + /// An LSPS1 (Channel Request) server event. |
| 102 | + #[cfg(lsps1_service)] |
| 103 | + LSPS1Service(lsps1::event::LSPS1ServiceEvent), |
| 104 | + /// An LSPS2 (JIT Channel) client event. |
| 105 | + LSPS2Client(lsps2::event::LSPS2ClientEvent), |
| 106 | + /// An LSPS2 (JIT Channel) server event. |
| 107 | + LSPS2Service(lsps2::event::LSPS2ServiceEvent), |
| 108 | +} |
| 109 | + |
| 110 | +struct EventFuture { |
| 111 | + event_queue: Arc<Mutex<VecDeque<Event>>>, |
| 112 | + waker: Arc<Mutex<Option<Waker>>>, |
| 113 | +} |
| 114 | + |
| 115 | +impl Future for EventFuture { |
| 116 | + type Output = Event; |
| 117 | + |
| 118 | + fn poll( |
| 119 | + self: core::pin::Pin<&mut Self>, cx: &mut core::task::Context<'_>, |
| 120 | + ) -> core::task::Poll<Self::Output> { |
| 121 | + if let Some(event) = self.event_queue.lock().unwrap().pop_front() { |
| 122 | + Poll::Ready(event) |
| 123 | + } else { |
| 124 | + *self.waker.lock().unwrap() = Some(cx.waker().clone()); |
| 125 | + Poll::Pending |
| 126 | + } |
| 127 | + } |
| 128 | +} |
| 129 | + |
| 130 | +#[cfg(test)] |
| 131 | +mod tests { |
| 132 | + #[tokio::test] |
| 133 | + #[cfg(feature = "std")] |
| 134 | + async fn event_queue_works() { |
| 135 | + use super::*; |
| 136 | + use crate::lsps0::event::LSPS0ClientEvent; |
| 137 | + use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey}; |
| 138 | + use core::sync::atomic::{AtomicU16, Ordering}; |
| 139 | + use std::sync::Arc; |
| 140 | + use std::time::Duration; |
| 141 | + |
| 142 | + let event_queue = Arc::new(EventQueue::new()); |
| 143 | + assert_eq!(event_queue.next_event(), None); |
| 144 | + |
| 145 | + let secp_ctx = Secp256k1::new(); |
| 146 | + let counterparty_node_id = |
| 147 | + PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()); |
| 148 | + let expected_event = Event::LSPS0Client(LSPS0ClientEvent::ListProtocolsResponse { |
| 149 | + counterparty_node_id, |
| 150 | + protocols: Vec::new(), |
| 151 | + }); |
| 152 | + |
| 153 | + for _ in 0..3 { |
| 154 | + event_queue.enqueue(expected_event.clone()); |
| 155 | + } |
| 156 | + |
| 157 | + assert_eq!(event_queue.wait_next_event(), expected_event); |
| 158 | + assert_eq!(event_queue.next_event_async().await, expected_event); |
| 159 | + assert_eq!(event_queue.next_event(), Some(expected_event.clone())); |
| 160 | + assert_eq!(event_queue.next_event(), None); |
| 161 | + |
| 162 | + // Check `next_event_async` won't return if the queue is empty and always rather timeout. |
| 163 | + tokio::select! { |
| 164 | + _ = tokio::time::sleep(Duration::from_millis(10)) => { |
| 165 | + // Timeout |
| 166 | + } |
| 167 | + _ = event_queue.next_event_async() => { |
| 168 | + panic!(); |
| 169 | + } |
| 170 | + } |
| 171 | + assert_eq!(event_queue.next_event(), None); |
| 172 | + |
| 173 | + // Check we get the expected number of events when polling/enqueuing concurrently. |
| 174 | + let enqueued_events = AtomicU16::new(0); |
| 175 | + let received_events = AtomicU16::new(0); |
| 176 | + let mut delayed_enqueue = false; |
| 177 | + |
| 178 | + for _ in 0..25 { |
| 179 | + event_queue.enqueue(expected_event.clone()); |
| 180 | + enqueued_events.fetch_add(1, Ordering::SeqCst); |
| 181 | + } |
| 182 | + |
| 183 | + loop { |
| 184 | + tokio::select! { |
| 185 | + _ = tokio::time::sleep(Duration::from_millis(10)), if !delayed_enqueue => { |
| 186 | + event_queue.enqueue(expected_event.clone()); |
| 187 | + enqueued_events.fetch_add(1, Ordering::SeqCst); |
| 188 | + delayed_enqueue = true; |
| 189 | + } |
| 190 | + e = event_queue.next_event_async() => { |
| 191 | + assert_eq!(e, expected_event); |
| 192 | + received_events.fetch_add(1, Ordering::SeqCst); |
| 193 | + |
| 194 | + event_queue.enqueue(expected_event.clone()); |
| 195 | + enqueued_events.fetch_add(1, Ordering::SeqCst); |
| 196 | + } |
| 197 | + e = event_queue.next_event_async() => { |
| 198 | + assert_eq!(e, expected_event); |
| 199 | + received_events.fetch_add(1, Ordering::SeqCst); |
| 200 | + } |
| 201 | + } |
| 202 | + |
| 203 | + if delayed_enqueue |
| 204 | + && received_events.load(Ordering::SeqCst) == enqueued_events.load(Ordering::SeqCst) |
| 205 | + { |
| 206 | + break; |
| 207 | + } |
| 208 | + } |
| 209 | + assert_eq!(event_queue.next_event(), None); |
| 210 | + |
| 211 | + // Check we operate correctly, even when mixing and matching blocking and async API calls. |
| 212 | + let (tx, mut rx) = tokio::sync::watch::channel(()); |
| 213 | + let thread_queue = Arc::clone(&event_queue); |
| 214 | + let thread_event = expected_event.clone(); |
| 215 | + std::thread::spawn(move || { |
| 216 | + let e = thread_queue.wait_next_event(); |
| 217 | + assert_eq!(e, thread_event); |
| 218 | + tx.send(()).unwrap(); |
| 219 | + }); |
| 220 | + |
| 221 | + let thread_queue = Arc::clone(&event_queue); |
| 222 | + let thread_event = expected_event.clone(); |
| 223 | + std::thread::spawn(move || { |
| 224 | + // Sleep a bit before we enqueue the events everybody is waiting for. |
| 225 | + std::thread::sleep(Duration::from_millis(20)); |
| 226 | + thread_queue.enqueue(thread_event.clone()); |
| 227 | + thread_queue.enqueue(thread_event.clone()); |
| 228 | + }); |
| 229 | + |
| 230 | + let e = event_queue.next_event_async().await; |
| 231 | + assert_eq!(e, expected_event.clone()); |
| 232 | + |
| 233 | + rx.changed().await.unwrap(); |
| 234 | + assert_eq!(event_queue.next_event(), None); |
| 235 | + } |
| 236 | +} |
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