3 files changed, 67 insertions, 12 deletions

diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index c3580ab67..e65bb0972 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -20,7 +20,7 @@ use crate::{
     main_loop::subscriptions::Subscriptions,
     project_model::workspace_loader,
     req,
-    server_world::{ServerWorld, ServerWorldState},
+    server_world::{ServerWorld, ServerWorldState, CompletedRequest},
     Result,
     InitializationOptions,
 };
@@ -45,6 +45,17 @@ enum Task {
     Notify(RawNotification),
 }
 
+struct PendingRequest {
+    received: Instant,
+    method: String,
+}
+
+impl From<(u64, PendingRequest)> for CompletedRequest {
+    fn from((id, pending): (u64, PendingRequest)) -> CompletedRequest {
+        CompletedRequest { id, method: pending.method, duration: pending.received.elapsed() }
+    }
+}
+
 const THREADPOOL_SIZE: usize = 8;
 
 pub fn main_loop(
@@ -97,7 +108,9 @@ pub fn main_loop(
     );
 
     log::info!("waiting for tasks to finish...");
-    task_receiver.into_iter().for_each(|task| on_task(task, msg_sender, &mut pending_requests));
+    task_receiver
+        .into_iter()
+        .for_each(|task| on_task(task, msg_sender, &mut pending_requests, &mut state));
     log::info!("...tasks have finished");
     log::info!("joining threadpool...");
     drop(pool);
@@ -159,7 +172,7 @@ fn main_loop_inner(
     task_sender: Sender<Task>,
     task_receiver: Receiver<Task>,
     state: &mut ServerWorldState,
-    pending_requests: &mut FxHashMap<u64, Instant>,
+    pending_requests: &mut FxHashMap<u64, PendingRequest>,
     subs: &mut Subscriptions,
 ) -> Result<()> {
     // We try not to index more than THREADPOOL_SIZE - 3 libraries at the same
@@ -195,7 +208,7 @@ fn main_loop_inner(
         let mut state_changed = false;
         match event {
             Event::Task(task) => {
-                on_task(task, msg_sender, pending_requests);
+                on_task(task, msg_sender, pending_requests, state);
                 state.maybe_collect_garbage();
             }
             Event::Vfs(task) => {
@@ -292,12 +305,15 @@ fn main_loop_inner(
 fn on_task(
     task: Task,
     msg_sender: &Sender<RawMessage>,
-    pending_requests: &mut FxHashMap<u64, Instant>,
+    pending_requests: &mut FxHashMap<u64, PendingRequest>,
+    state: &mut ServerWorldState,
 ) {
     match task {
         Task::Respond(response) => {
-            if let Some(request_received) = pending_requests.remove(&response.id) {
-                log::info!("handled req#{} in {:?}", response.id, request_received.elapsed());
+            if let Some(pending) = pending_requests.remove(&response.id) {
+                let completed = CompletedRequest::from((response.id, pending));
+                log::info!("handled req#{} in {:?}", completed.id, completed.duration);
+                state.complete_request(completed);
                 msg_sender.send(response.into()).unwrap();
             }
         }
@@ -309,12 +325,13 @@ fn on_task(
 
 fn on_request(
     world: &mut ServerWorldState,
-    pending_requests: &mut FxHashMap<u64, Instant>,
+    pending_requests: &mut FxHashMap<u64, PendingRequest>,
     pool: &ThreadPool,
     sender: &Sender<Task>,
     request_received: Instant,
     req: RawRequest,
 ) -> Result<Option<RawRequest>> {
+    let method = req.method.clone();
     let mut pool_dispatcher = PoolDispatcher { req: Some(req), res: None, pool, world, sender };
     let req = pool_dispatcher
         .on::<req::AnalyzerStatus>(handlers::handle_analyzer_status)?
@@ -348,7 +365,8 @@ fn on_request(
         .finish();
     match req {
         Ok(id) => {
-            let prev = pending_requests.insert(id, request_received);
+            let prev =
+                pending_requests.insert(id, PendingRequest { method, received: request_received });
             assert!(prev.is_none(), "duplicate request: {}", id);
             Ok(None)
         }
@@ -359,7 +377,7 @@ fn on_request(
 fn on_notification(
     msg_sender: &Sender<RawMessage>,
     state: &mut ServerWorldState,
-    pending_requests: &mut FxHashMap<u64, Instant>,
+    pending_requests: &mut FxHashMap<u64, PendingRequest>,
     subs: &mut Subscriptions,
     not: RawNotification,
 ) -> Result<()> {
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index e36db12b3..dc817f2d9 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -1,3 +1,5 @@
+use std::{io::Write as _, fmt::Write as _};
+
 use gen_lsp_server::ErrorCode;
 use lsp_types::{
     CodeActionResponse, CodeLens, Command, Diagnostic, DiagnosticSeverity, CodeAction,
@@ -16,7 +18,6 @@ use ra_prof::profile;
 use rustc_hash::FxHashMap;
 use serde::{Serialize, Deserialize};
 use serde_json::to_value;
-use std::io::Write;
 use url_serde::Ser;
 
 use crate::{
@@ -28,7 +29,14 @@ use crate::{
 };
 
 pub fn handle_analyzer_status(world: ServerWorld, _: ()) -> Result<String> {
-    Ok(world.status())
+    let mut buf = world.status();
+    writeln!(buf, "\n\nrequests:").unwrap();
+    let requests = world.latest_completed_requests.read();
+    for (idx, r) in requests.iter().enumerate() {
+        let current = if idx == world.request_idx { "*" } else { " " };
+        writeln!(buf, "{:4}{}{:<36}: {:?}", r.id, current, r.method, r.duration).unwrap();
+    }
+    Ok(buf)
 }
 
 pub fn handle_syntax_tree(world: ServerWorld, params: req::SyntaxTreeParams) -> Result<String> {
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/server_world.rs
index b2808b817..b63927a4f 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/server_world.rs
@@ -1,6 +1,7 @@
 use std::{
     path::{Path, PathBuf},
     sync::Arc,
+    time::Duration,
 };
 
 use lsp_types::Url;
@@ -28,12 +29,26 @@ pub struct ServerWorldState {
     pub workspaces: Arc<Vec<ProjectWorkspace>>,
     pub analysis_host: AnalysisHost,
     pub vfs: Arc<RwLock<Vfs>>,
+    // hand-rolling VecDeque here to print things in a nicer way
+    pub latest_completed_requests: Arc<RwLock<[CompletedRequest; N_COMPLETED_REQUESTS]>>,
+    pub request_idx: usize,
 }
 
+const N_COMPLETED_REQUESTS: usize = 10;
+
 pub struct ServerWorld {
     pub workspaces: Arc<Vec<ProjectWorkspace>>,
     pub analysis: Analysis,
     pub vfs: Arc<RwLock<Vfs>>,
+    pub latest_completed_requests: Arc<RwLock<[CompletedRequest; N_COMPLETED_REQUESTS]>>,
+    pub request_idx: usize,
+}
+
+#[derive(Debug, Default)]
+pub struct CompletedRequest {
+    pub id: u64,
+    pub method: String,
+    pub duration: Duration,
 }
 
 impl ServerWorldState {
@@ -73,6 +88,8 @@ impl ServerWorldState {
             workspaces: Arc::new(workspaces),
             analysis_host,
             vfs: Arc::new(RwLock::new(vfs)),
+            latest_completed_requests: Default::default(),
+            request_idx: 0,
         }
     }
 
@@ -137,6 +154,8 @@ impl ServerWorldState {
             workspaces: Arc::clone(&self.workspaces),
             analysis: self.analysis_host.analysis(),
             vfs: Arc::clone(&self.vfs),
+            latest_completed_requests: Arc::clone(&self.latest_completed_requests),
+            request_idx: self.request_idx.checked_sub(1).unwrap_or(N_COMPLETED_REQUESTS - 1),
         }
     }
 
@@ -147,6 +166,16 @@ impl ServerWorldState {
     pub fn collect_garbage(&mut self) {
         self.analysis_host.collect_garbage()
     }
+
+    pub fn complete_request(&mut self, request: CompletedRequest) {
+        // special case: don't track status request itself
+        if request.method == "rust-analyzer/analyzerStatus" {
+            return;
+        }
+        let idx = self.request_idx;
+        self.latest_completed_requests.write()[idx] = request;
+        self.request_idx = (idx + 1) % N_COMPLETED_REQUESTS;
+    }
 }
 
 impl ServerWorld {