2 files changed, 290 insertions, 0 deletions

diff --git a/crates/vfs-notify/src/include.rs b/crates/vfs-notify/src/include.rs
new file mode 100644
index 000000000..7378766f5
--- /dev/null
+++ b/crates/vfs-notify/src/include.rs
@@ -0,0 +1,43 @@
+//! See `Include`.
+
+use std::convert::TryFrom;
+
+use globset::{Glob, GlobSet, GlobSetBuilder};
+use paths::{RelPath, RelPathBuf};
+
+/// `Include` is the opposite of .gitignore.
+///
+/// It describes the set of files inside some directory.
+///
+/// The current implementation is very limited, it allows white-listing file
+/// globs and black-listing directories.
+#[derive(Debug, Clone)]
+pub(crate) struct Include {
+    include_files: GlobSet,
+    exclude_dirs: Vec<RelPathBuf>,
+}
+
+impl Include {
+    pub(crate) fn new(include: Vec<String>) -> Include {
+        let mut include_files = GlobSetBuilder::new();
+        let mut exclude_dirs = Vec::new();
+
+        for glob in include {
+            if glob.starts_with("!/") {
+                if let Ok(path) = RelPathBuf::try_from(&glob["!/".len()..]) {
+                    exclude_dirs.push(path)
+                }
+            } else {
+                include_files.add(Glob::new(&glob).unwrap());
+            }
+        }
+        let include_files = include_files.build().unwrap();
+        Include { include_files, exclude_dirs }
+    }
+    pub(crate) fn include_file(&self, path: &RelPath) -> bool {
+        self.include_files.is_match(path)
+    }
+    pub(crate) fn exclude_dir(&self, path: &RelPath) -> bool {
+        self.exclude_dirs.iter().any(|excluded| path.starts_with(excluded))
+    }
+}
diff --git a/crates/vfs-notify/src/lib.rs b/crates/vfs-notify/src/lib.rs
new file mode 100644
index 000000000..baee6ddc8
--- /dev/null
+++ b/crates/vfs-notify/src/lib.rs
@@ -0,0 +1,247 @@
+//! An implementation of `loader::Handle`, based on `walkdir` and `notify`.
+//!
+//! The file watching bits here are untested and quite probably buggy. For this
+//! reason, by default we don't watch files and rely on editor's file watching
+//! capabilities.
+//!
+//! Hopefully, one day a reliable file watching/walking crate appears on
+//! crates.io, and we can reduce this to trivial glue code.
+mod include;
+
+use std::convert::{TryFrom, TryInto};
+
+use crossbeam_channel::{select, unbounded, Receiver};
+use notify::{RecommendedWatcher, RecursiveMode, Watcher};
+use paths::{AbsPath, AbsPathBuf};
+use rustc_hash::FxHashSet;
+use vfs::loader;
+use walkdir::WalkDir;
+
+use crate::include::Include;
+
+#[derive(Debug)]
+pub struct LoaderHandle {
+    // Relative order of fields below is significant.
+    sender: crossbeam_channel::Sender<Message>,
+    _thread: jod_thread::JoinHandle,
+}
+
+#[derive(Debug)]
+enum Message {
+    Config(loader::Config),
+    Invalidate(AbsPathBuf),
+}
+
+impl loader::Handle for LoaderHandle {
+    fn spawn(sender: loader::Sender) -> LoaderHandle {
+        let actor = LoaderActor::new(sender);
+        let (sender, receiver) = unbounded::<Message>();
+        let thread = jod_thread::spawn(move || actor.run(receiver));
+        LoaderHandle { sender, _thread: thread }
+    }
+    fn set_config(&mut self, config: loader::Config) {
+        self.sender.send(Message::Config(config)).unwrap()
+    }
+    fn invalidate(&mut self, path: AbsPathBuf) {
+        self.sender.send(Message::Invalidate(path)).unwrap();
+    }
+    fn load_sync(&mut self, path: &AbsPathBuf) -> Option<Vec<u8>> {
+        read(path)
+    }
+}
+
+type NotifyEvent = notify::Result<notify::Event>;
+
+struct LoaderActor {
+    config: Vec<(AbsPathBuf, Include, bool)>,
+    watched_paths: FxHashSet<AbsPathBuf>,
+    sender: loader::Sender,
+    // Drop order of fields bellow is significant,
+    watcher: Option<RecommendedWatcher>,
+    watcher_receiver: Receiver<NotifyEvent>,
+}
+
+#[derive(Debug)]
+enum Event {
+    Message(Message),
+    NotifyEvent(NotifyEvent),
+}
+
+impl LoaderActor {
+    fn new(sender: loader::Sender) -> LoaderActor {
+        let (watcher_sender, watcher_receiver) = unbounded();
+        let watcher = log_notify_error(Watcher::new_immediate(move |event| {
+            watcher_sender.send(event).unwrap()
+        }));
+
+        LoaderActor {
+            watcher,
+            watcher_receiver,
+            watched_paths: FxHashSet::default(),
+            sender,
+            config: Vec::new(),
+        }
+    }
+
+    fn run(mut self, receiver: Receiver<Message>) {
+        while let Some(event) = self.next_event(&receiver) {
+            log::debug!("vfs-notify event: {:?}", event);
+            match event {
+                Event::Message(msg) => match msg {
+                    Message::Config(config) => {
+                        let n_entries_total = config.load.len();
+                        self.send(loader::Message::Progress { n_entries_total, n_entries_done: 0 });
+
+                        self.unwatch_all();
+                        self.config.clear();
+
+                        for (i, entry) in config.load.into_iter().enumerate() {
+                            let watch = config.watch.contains(&i);
+                            let files = self.load_entry(entry, watch);
+                            self.send(loader::Message::Loaded { files });
+                            self.send(loader::Message::Progress {
+                                n_entries_total,
+                                n_entries_done: i + 1,
+                            });
+                        }
+                        self.config.sort_by(|x, y| x.0.cmp(&y.0));
+                    }
+                    Message::Invalidate(path) => {
+                        let contents = read(path.as_path());
+                        let files = vec![(path, contents)];
+                        self.send(loader::Message::Loaded { files });
+                    }
+                },
+                Event::NotifyEvent(event) => {
+                    if let Some(event) = log_notify_error(event) {
+                        let files = event
+                            .paths
+                            .into_iter()
+                            .map(|path| AbsPathBuf::try_from(path).unwrap())
+                            .filter_map(|path| {
+                                let is_dir = path.is_dir();
+                                let is_file = path.is_file();
+
+                                let config_idx =
+                                    match self.config.binary_search_by(|it| it.0.cmp(&path)) {
+                                        Ok(it) => it,
+                                        Err(it) => it.saturating_sub(1),
+                                    };
+                                let include = self.config.get(config_idx).and_then(|it| {
+                                    let rel_path = path.strip_prefix(&it.0)?;
+                                    Some((rel_path, &it.1))
+                                });
+
+                                if let Some((rel_path, include)) = include {
+                                    if is_dir && include.exclude_dir(&rel_path)
+                                        || is_file && !include.include_file(&rel_path)
+                                    {
+                                        return None;
+                                    }
+                                }
+
+                                if is_dir {
+                                    self.watch(path);
+                                    return None;
+                                }
+                                if !is_file {
+                                    return None;
+                                }
+                                let contents = read(&path);
+                                Some((path, contents))
+                            })
+                            .collect();
+                        self.send(loader::Message::Loaded { files })
+                    }
+                }
+            }
+        }
+    }
+    fn next_event(&self, receiver: &Receiver<Message>) -> Option<Event> {
+        select! {
+            recv(receiver) -> it => it.ok().map(Event::Message),
+            recv(&self.watcher_receiver) -> it => Some(Event::NotifyEvent(it.unwrap())),
+        }
+    }
+    fn load_entry(
+        &mut self,
+        entry: loader::Entry,
+        watch: bool,
+    ) -> Vec<(AbsPathBuf, Option<Vec<u8>>)> {
+        match entry {
+            loader::Entry::Files(files) => files
+                .into_iter()
+                .map(|file| {
+                    if watch {
+                        self.watch(file.clone())
+                    }
+                    let contents = read(file.as_path());
+                    (file, contents)
+                })
+                .collect::<Vec<_>>(),
+            loader::Entry::Directory { path, include } => {
+                let include = Include::new(include);
+                self.config.push((path.clone(), include.clone(), watch));
+
+                let files = WalkDir::new(&path)
+                    .into_iter()
+                    .filter_entry(|entry| {
+                        let abs_path: &AbsPath = entry.path().try_into().unwrap();
+                        match abs_path.strip_prefix(&path) {
+                            Some(rel_path) => {
+                                !(entry.file_type().is_dir() && include.exclude_dir(rel_path))
+                            }
+                            None => false,
+                        }
+                    })
+                    .filter_map(|entry| entry.ok())
+                    .filter_map(|entry| {
+                        let is_dir = entry.file_type().is_dir();
+                        let is_file = entry.file_type().is_file();
+                        let abs_path = AbsPathBuf::try_from(entry.into_path()).unwrap();
+                        if is_dir {
+                            self.watch(abs_path.clone());
+                        }
+                        let rel_path = abs_path.strip_prefix(&path)?;
+                        if is_file && include.include_file(&rel_path) {
+                            Some(abs_path)
+                        } else {
+                            None
+                        }
+                    });
+
+                files
+                    .map(|file| {
+                        let contents = read(file.as_path());
+                        (file, contents)
+                    })
+                    .collect()
+            }
+        }
+    }
+
+    fn watch(&mut self, path: AbsPathBuf) {
+        if let Some(watcher) = &mut self.watcher {
+            log_notify_error(watcher.watch(&path, RecursiveMode::NonRecursive));
+            self.watched_paths.insert(path);
+        }
+    }
+    fn unwatch_all(&mut self) {
+        if let Some(watcher) = &mut self.watcher {
+            for path in self.watched_paths.drain() {
+                log_notify_error(watcher.unwatch(path));
+            }
+        }
+    }
+    fn send(&mut self, msg: loader::Message) {
+        (self.sender)(msg)
+    }
+}
+
+fn read(path: &AbsPath) -> Option<Vec<u8>> {
+    std::fs::read(path).ok()
+}
+
+fn log_notify_error<T>(res: notify::Result<T>) -> Option<T> {
+    res.map_err(|err| log::warn!("notify error: {}", err)).ok()
+}