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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
use crate::colors;
use core::task::{Context, Poll};
use deno_core::error::AnyError;
use deno_core::futures::stream::{Stream, StreamExt};
use deno_core::futures::Future;
use notify::event::Event as NotifyEvent;
use notify::event::EventKind;
use notify::Config;
use notify::Error as NotifyError;
use notify::RecommendedWatcher;
use notify::RecursiveMode;
use notify::Watcher;
use std::path::PathBuf;
use std::pin::Pin;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
use std::time::Duration;
use tokio::select;
use tokio::time::{interval, Interval};
const DEBOUNCE_INTERVAL_MS: Duration = Duration::from_millis(200);
// TODO(bartlomieju): rename
type WatchFuture = Pin<Box<dyn Future<Output = Result<(), AnyError>>>>;
struct Debounce {
interval: Interval,
event_detected: Arc<AtomicBool>,
}
impl Debounce {
fn new() -> Self {
Self {
interval: interval(DEBOUNCE_INTERVAL_MS),
event_detected: Arc::new(AtomicBool::new(false)),
}
}
}
impl Stream for Debounce {
type Item = ();
/// Note that this never returns `Poll::Ready(None)`, which means that file watcher will be alive
/// until the Deno process is terminated.
fn poll_next(
self: Pin<&mut Self>,
cx: &mut Context,
) -> Poll<Option<Self::Item>> {
let inner = self.get_mut();
if inner.event_detected.load(Ordering::Relaxed) {
inner.event_detected.store(false, Ordering::Relaxed);
Poll::Ready(Some(()))
} else {
let _ = inner.interval.poll_tick(cx);
Poll::Pending
}
}
}
async fn error_handler(watch_future: WatchFuture) {
let result = watch_future.await;
if let Err(err) = result {
let msg = format!("{}: {}", colors::red_bold("error"), err.to_string(),);
eprintln!("{}", msg);
}
}
pub async fn watch_func<F>(
paths: &[PathBuf],
closure: F,
) -> Result<(), AnyError>
where
F: Fn() -> WatchFuture,
{
let mut debounce = Debounce::new();
// This binding is required for the watcher to work properly without being dropped.
let _watcher = new_watcher(paths, &debounce)?;
loop {
let func = error_handler(closure());
let mut is_file_changed = false;
select! {
_ = debounce.next() => {
is_file_changed = true;
info!(
"{} File change detected! Restarting!",
colors::intense_blue("Watcher"),
);
},
_ = func => {},
}
if !is_file_changed {
info!(
"{} Process terminated! Restarting on file change...",
colors::intense_blue("Watcher"),
);
debounce.next().await;
info!(
"{} File change detected! Restarting!",
colors::intense_blue("Watcher"),
);
}
}
}
fn new_watcher(
paths: &[PathBuf],
debounce: &Debounce,
) -> Result<RecommendedWatcher, AnyError> {
let event_detected = Arc::clone(&debounce.event_detected);
let mut watcher: RecommendedWatcher = Watcher::new_immediate(
move |res: Result<NotifyEvent, NotifyError>| {
if let Ok(event) = res {
if matches!(event.kind, EventKind::Create(_) | EventKind::Modify(_) | EventKind::Remove(_))
{
event_detected.store(true, Ordering::Relaxed);
}
}
},
)?;
watcher.configure(Config::PreciseEvents(true)).unwrap();
for path in paths {
watcher.watch(path, RecursiveMode::NonRecursive)?;
}
Ok(watcher)
}
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