use std::{collections::HashMap, path::PathBuf, sync::Weak}; use globset::{GlobBuilder, GlobSetBuilder}; use tokio::sync::mpsc; use crate::{lsp, Client, LanguageServerId}; enum Event { FileChanged { path: PathBuf, }, Register { client_id: LanguageServerId, client: Weak, registration_id: String, options: lsp::DidChangeWatchedFilesRegistrationOptions, }, Unregister { client_id: LanguageServerId, registration_id: String, }, RemoveClient { client_id: LanguageServerId, }, } #[derive(Default)] struct ClientState { client: Weak, registered: HashMap, } /// The Handler uses a dedicated tokio task to respond to file change events by /// forwarding changes to LSPs that have registered for notifications with a /// matching glob. /// /// When an LSP registers for the DidChangeWatchedFiles notification, the /// Handler is notified by sending the registration details in addition to a /// weak reference to the LSP client. This is done so that the Handler can have /// access to the client without preventing the client from being dropped if it /// is closed and the Handler isn't properly notified. #[derive(Clone, Debug)] pub struct Handler { tx: mpsc::UnboundedSender, } impl Default for Handler { fn default() -> Self { Self::new() } } impl Handler { pub fn new() -> Self { let (tx, rx) = mpsc::unbounded_channel(); tokio::spawn(Self::run(rx)); Self { tx } } pub fn register( &self, client_id: LanguageServerId, client: Weak, registration_id: String, options: lsp::DidChangeWatchedFilesRegistrationOptions, ) { let _ = self.tx.send(Event::Register { client_id, client, registration_id, options, }); } pub fn unregister(&self, client_id: LanguageServerId, registration_id: String) { let _ = self.tx.send(Event::Unregister { client_id, registration_id, }); } pub fn file_changed(&self, path: PathBuf) { let _ = self.tx.send(Event::FileChanged { path }); } pub fn remove_client(&self, client_id: LanguageServerId) { let _ = self.tx.send(Event::RemoveClient { client_id }); } async fn run(mut rx: mpsc::UnboundedReceiver) { let mut state: HashMap = HashMap::new(); while let Some(event) = rx.recv().await { match event { Event::FileChanged { path } => { log::debug!("Received file event for {:?}", &path); state.retain(|id, client_state| { if !client_state .registered .values() .any(|glob| glob.is_match(&path)) { return true; } let Some(client) = client_state.client.upgrade() else { log::warn!("LSP client was dropped: {id}"); return false; }; let Ok(uri) = lsp::Url::from_file_path(&path) else { return true; }; log::debug!( "Sending didChangeWatchedFiles notification to client '{}'", client.name() ); if let Err(err) = crate::block_on(client .did_change_watched_files(vec![lsp::FileEvent { uri, // We currently always send the CHANGED state // since we don't actually have more context at // the moment. typ: lsp::FileChangeType::CHANGED, }])) { log::warn!("Failed to send didChangeWatchedFiles notification to client: {err}"); } true }); } Event::Register { client_id, client, registration_id, options: ops, } => { log::debug!( "Registering didChangeWatchedFiles for client '{}' with id '{}'", client_id, registration_id ); let entry = state.entry(client_id).or_default(); entry.client = client; let mut builder = GlobSetBuilder::new(); for watcher in ops.watchers { if let lsp::GlobPattern::String(pattern) = watcher.glob_pattern { if let Ok(glob) = GlobBuilder::new(&pattern).build() { builder.add(glob); } } } match builder.build() { Ok(globset) => { entry.registered.insert(registration_id, globset); } Err(err) => { // Remove any old state for that registration id and // remove the entire client if it's now empty. entry.registered.remove(®istration_id); if entry.registered.is_empty() { state.remove(&client_id); } log::warn!( "Unable to build globset for LSP didChangeWatchedFiles {err}" ) } } } Event::Unregister { client_id, registration_id, } => { log::debug!( "Unregistering didChangeWatchedFiles with id '{}' for client '{}'", registration_id, client_id ); if let Some(client_state) = state.get_mut(&client_id) { client_state.registered.remove(®istration_id); if client_state.registered.is_empty() { state.remove(&client_id); } } } Event::RemoveClient { client_id } => { log::debug!("Removing LSP client: {client_id}"); state.remove(&client_id); } } } } }