1use notify::EventKind;
  2use parking_lot::Mutex;
  3use std::sync::{Arc, OnceLock};
  4use util::{paths::SanitizedPath, ResultExt};
  5
  6use crate::{PathEvent, PathEventKind, Watcher};
  7
  8pub struct FsWatcher {
  9    tx: smol::channel::Sender<()>,
 10    pending_path_events: Arc<Mutex<Vec<PathEvent>>>,
 11}
 12
 13impl FsWatcher {
 14    pub fn new(
 15        tx: smol::channel::Sender<()>,
 16        pending_path_events: Arc<Mutex<Vec<PathEvent>>>,
 17    ) -> Self {
 18        Self {
 19            tx,
 20            pending_path_events,
 21        }
 22    }
 23}
 24
 25impl Watcher for FsWatcher {
 26    fn add(&self, path: &std::path::Path) -> gpui::Result<()> {
 27        let root_path = SanitizedPath::from(path);
 28
 29        let tx = self.tx.clone();
 30        let pending_paths = self.pending_path_events.clone();
 31
 32        use notify::Watcher;
 33
 34        global({
 35            |g| {
 36                g.add(move |event: &notify::Event| {
 37                    let kind = match event.kind {
 38                        EventKind::Create(_) => Some(PathEventKind::Created),
 39                        EventKind::Modify(_) => Some(PathEventKind::Changed),
 40                        EventKind::Remove(_) => Some(PathEventKind::Removed),
 41                        // Adding this fix a weird bug on Linux after upgrading notify
 42                        // https://github.com/zed-industries/zed/actions/runs/14085230504/job/39449448832
 43                        EventKind::Access(_) => return,
 44                        _ => None,
 45                    };
 46                    let mut path_events = event
 47                        .paths
 48                        .iter()
 49                        .filter_map(|event_path| {
 50                            let event_path = SanitizedPath::from(event_path);
 51                            event_path.starts_with(&root_path).then(|| PathEvent {
 52                                path: event_path.as_path().to_path_buf(),
 53                                kind,
 54                            })
 55                        })
 56                        .collect::<Vec<_>>();
 57
 58                    if !path_events.is_empty() {
 59                        path_events.sort();
 60                        let mut pending_paths = pending_paths.lock();
 61                        if pending_paths.is_empty() {
 62                            tx.try_send(()).ok();
 63                        }
 64                        util::extend_sorted(
 65                            &mut *pending_paths,
 66                            path_events,
 67                            usize::MAX,
 68                            |a, b| a.path.cmp(&b.path),
 69                        );
 70                    }
 71                })
 72            }
 73        })?;
 74
 75        global(|g| {
 76            g.watcher
 77                .lock()
 78                .watch(path, notify::RecursiveMode::NonRecursive)
 79        })??;
 80
 81        Ok(())
 82    }
 83
 84    fn remove(&self, path: &std::path::Path) -> gpui::Result<()> {
 85        use notify::Watcher;
 86        Ok(global(|w| w.watcher.lock().unwatch(path))??)
 87    }
 88}
 89
 90pub struct GlobalWatcher {
 91    // two mutexes because calling watcher.add triggers an watcher.event, which needs watchers.
 92    #[cfg(target_os = "linux")]
 93    pub(super) watcher: Mutex<notify::INotifyWatcher>,
 94    #[cfg(target_os = "freebsd")]
 95    pub(super) watcher: Mutex<notify::KqueueWatcher>,
 96    #[cfg(target_os = "windows")]
 97    pub(super) watcher: Mutex<notify::ReadDirectoryChangesWatcher>,
 98    pub(super) watchers: Mutex<Vec<Box<dyn Fn(&notify::Event) + Send + Sync>>>,
 99}
100
101impl GlobalWatcher {
102    pub(super) fn add(&self, cb: impl Fn(&notify::Event) + Send + Sync + 'static) {
103        self.watchers.lock().push(Box::new(cb))
104    }
105}
106
107static FS_WATCHER_INSTANCE: OnceLock<anyhow::Result<GlobalWatcher, notify::Error>> =
108    OnceLock::new();
109
110fn handle_event(event: Result<notify::Event, notify::Error>) {
111    let Some(event) = event.log_err() else { return };
112    global::<()>(move |watcher| {
113        for f in watcher.watchers.lock().iter() {
114            f(&event)
115        }
116    })
117    .log_err();
118}
119
120pub fn global<T>(f: impl FnOnce(&GlobalWatcher) -> T) -> anyhow::Result<T> {
121    let result = FS_WATCHER_INSTANCE.get_or_init(|| {
122        notify::recommended_watcher(handle_event).map(|file_watcher| GlobalWatcher {
123            watcher: Mutex::new(file_watcher),
124            watchers: Default::default(),
125        })
126    });
127    match result {
128        Ok(g) => Ok(f(g)),
129        Err(e) => Err(anyhow::anyhow!("{}", e)),
130    }
131}