5 files changed, 114 insertions, 80 deletions

diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index 0184c8546..e3cae94f4 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -1,5 +1,6 @@
 mod handlers;
 mod subscriptions;
+pub(crate) mod pending_requests;
 
 use std::{fmt, path::PathBuf, sync::Arc, time::Instant, any::TypeId};
 
@@ -12,16 +13,18 @@ use gen_lsp_server::{
 use lsp_types::NumberOrString;
 use ra_ide_api::{Canceled, FileId, LibraryData};
 use ra_vfs::VfsTask;
-use rustc_hash::FxHashMap;
 use serde::{de::DeserializeOwned, Serialize};
 use threadpool::ThreadPool;
 use ra_prof::profile;
 
 use crate::{
-    main_loop::subscriptions::Subscriptions,
+    main_loop::{
+        subscriptions::Subscriptions,
+        pending_requests::{PendingRequests, PendingRequest},
+    },
     project_model::workspace_loader,
     req,
-    server_world::{ServerWorld, ServerWorldState, CompletedRequest},
+    server_world::{ServerWorld, ServerWorldState},
     Result,
     InitializationOptions,
 };
@@ -42,37 +45,12 @@ impl LspError {
     }
 }
 
-#[derive(Debug)]
-enum Task {
-    Respond(RawResponse),
-    Notify(RawNotification),
-}
-
-struct PendingRequest {
-    id: u64,
-    received: Instant,
-    method: String,
-}
-
-impl From<PendingRequest> for CompletedRequest {
-    fn from(pending: PendingRequest) -> CompletedRequest {
-        CompletedRequest {
-            id: pending.id,
-            method: pending.method,
-            duration: pending.received.elapsed(),
-        }
-    }
-}
-
 pub fn main_loop(
     ws_roots: Vec<PathBuf>,
     options: InitializationOptions,
     msg_receiver: &Receiver<RawMessage>,
     msg_sender: &Sender<RawMessage>,
 ) -> Result<()> {
-    let pool = ThreadPool::new(THREADPOOL_SIZE);
-    let (task_sender, task_receiver) = unbounded::<Task>();
-
     // FIXME: support dynamic workspace loading.
     let workspaces = {
         let ws_worker = workspace_loader();
@@ -97,10 +75,12 @@ pub fn main_loop(
 
     let mut state = ServerWorldState::new(ws_roots, workspaces);
 
-    log::info!("server initialized, serving requests");
+    let pool = ThreadPool::new(THREADPOOL_SIZE);
+    let (task_sender, task_receiver) = unbounded::<Task>();
+    let mut pending_requests = PendingRequests::default();
+    let mut subs = Subscriptions::default();
 
-    let mut pending_requests = FxHashMap::default();
-    let mut subs = Subscriptions::new();
+    log::info!("server initialized, serving requests");
     let main_res = main_loop_inner(
         options,
         &pool,
@@ -128,6 +108,12 @@ pub fn main_loop(
     main_res
 }
 
+#[derive(Debug)]
+enum Task {
+    Respond(RawResponse),
+    Notify(RawNotification),
+}
+
 enum Event {
     Msg(RawMessage),
     Task(Task),
@@ -178,7 +164,7 @@ fn main_loop_inner(
     task_sender: Sender<Task>,
     task_receiver: Receiver<Task>,
     state: &mut ServerWorldState,
-    pending_requests: &mut FxHashMap<u64, PendingRequest>,
+    pending_requests: &mut PendingRequests,
     subs: &mut Subscriptions,
 ) -> Result<()> {
     // We try not to index more than MAX_IN_FLIGHT_LIBS libraries at the same
@@ -202,15 +188,16 @@ fn main_loop_inner(
             },
             recv(libdata_receiver) -> data => Event::Lib(data.unwrap())
         };
-        // NOTE: don't count blocking select! call as a loop-turn time
-        let _p = profile("main_loop_inner/loop-turn");
         let loop_start = Instant::now();
 
+        // NOTE: don't count blocking select! call as a loop-turn time
+        let _p = profile("main_loop_inner/loop-turn");
         log::info!("loop turn = {:?}", event);
         let queue_count = pool.queued_count();
         if queue_count > 0 {
             log::info!("queued count = {}", queue_count);
         }
+
         let mut state_changed = false;
         match event {
             Event::Task(task) => {
@@ -311,13 +298,12 @@ fn main_loop_inner(
 fn on_task(
     task: Task,
     msg_sender: &Sender<RawMessage>,
-    pending_requests: &mut FxHashMap<u64, PendingRequest>,
+    pending_requests: &mut PendingRequests,
     state: &mut ServerWorldState,
 ) {
     match task {
         Task::Respond(response) => {
-            if let Some(pending) = pending_requests.remove(&response.id) {
-                let completed = CompletedRequest::from(pending);
+            if let Some(completed) = pending_requests.finish(response.id) {
                 log::info!("handled req#{} in {:?}", completed.id, completed.duration);
                 state.complete_request(completed);
                 msg_sender.send(response.into()).unwrap();
@@ -331,7 +317,7 @@ fn on_task(
 
 fn on_request(
     world: &mut ServerWorldState,
-    pending_requests: &mut FxHashMap<u64, PendingRequest>,
+    pending_requests: &mut PendingRequests,
     pool: &ThreadPool,
     sender: &Sender<Task>,
     request_received: Instant,
@@ -371,9 +357,7 @@ fn on_request(
         .finish();
     match req {
         Ok(id) => {
-            let prev = pending_requests
-                .insert(id, PendingRequest { id, method, received: request_received });
-            assert!(prev.is_none(), "duplicate request: {}", id);
+            pending_requests.start(PendingRequest { id, method, received: request_received });
             Ok(None)
         }
         Err(req) => Ok(Some(req)),
@@ -383,7 +367,7 @@ fn on_request(
 fn on_notification(
     msg_sender: &Sender<RawMessage>,
     state: &mut ServerWorldState,
-    pending_requests: &mut FxHashMap<u64, PendingRequest>,
+    pending_requests: &mut PendingRequests,
     subs: &mut Subscriptions,
     not: RawNotification,
 ) -> Result<()> {
@@ -395,7 +379,7 @@ fn on_notification(
                     panic!("string id's not supported: {:?}", id);
                 }
             };
-            if pending_requests.remove(&id).is_some() {
+            if pending_requests.cancel(id) {
                 let response = RawResponse::err(
                     id,
                     ErrorCode::RequestCanceled as i32,
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 0ebfd641d..8cfb6a192 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -31,10 +31,10 @@ use crate::{
 pub fn handle_analyzer_status(world: ServerWorld, _: ()) -> Result<String> {
     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}{}ms", r.id, current, r.method, r.duration.as_millis()).unwrap();
+    let requests = world.latest_requests.read();
+    for (is_last, r) in requests.iter() {
+        let mark = if is_last { "*" } else { " " };
+        writeln!(buf, "{}{:4} {:<36}{}ms", mark, r.id, r.method, r.duration.as_millis()).unwrap();
     }
     Ok(buf)
 }
diff --git a/crates/ra_lsp_server/src/main_loop/pending_requests.rs b/crates/ra_lsp_server/src/main_loop/pending_requests.rs
new file mode 100644
index 000000000..741770e45
--- /dev/null
+++ b/crates/ra_lsp_server/src/main_loop/pending_requests.rs
@@ -0,0 +1,72 @@
+use std::time::{Duration, Instant};
+
+use rustc_hash::FxHashMap;
+
+#[derive(Debug)]
+pub struct CompletedRequest {
+    pub id: u64,
+    pub method: String,
+    pub duration: Duration,
+}
+
+#[derive(Debug)]
+pub(crate) struct PendingRequest {
+    pub(crate) id: u64,
+    pub(crate) method: String,
+    pub(crate) received: Instant,
+}
+
+impl From<PendingRequest> for CompletedRequest {
+    fn from(pending: PendingRequest) -> CompletedRequest {
+        CompletedRequest {
+            id: pending.id,
+            method: pending.method,
+            duration: pending.received.elapsed(),
+        }
+    }
+}
+
+#[derive(Debug, Default)]
+pub(crate) struct PendingRequests {
+    map: FxHashMap<u64, PendingRequest>,
+}
+
+impl PendingRequests {
+    pub(crate) fn start(&mut self, request: PendingRequest) {
+        let id = request.id;
+        let prev = self.map.insert(id, request);
+        assert!(prev.is_none(), "duplicate request with id {}", id);
+    }
+    pub(crate) fn cancel(&mut self, id: u64) -> bool {
+        self.map.remove(&id).is_some()
+    }
+    pub(crate) fn finish(&mut self, id: u64) -> Option<CompletedRequest> {
+        self.map.remove(&id).map(CompletedRequest::from)
+    }
+}
+
+const N_COMPLETED_REQUESTS: usize = 10;
+
+#[derive(Debug, Default)]
+pub struct LatestRequests {
+    // hand-rolling VecDeque here to print things in a nicer way
+    buf: [Option<CompletedRequest>; N_COMPLETED_REQUESTS],
+    idx: usize,
+}
+
+impl LatestRequests {
+    pub(crate) fn record(&mut self, request: CompletedRequest) {
+        // special case: don't track status request itself
+        if request.method == "rust-analyzer/analyzerStatus" {
+            return;
+        }
+        let idx = self.idx;
+        self.buf[idx] = Some(request);
+        self.idx = (idx + 1) % N_COMPLETED_REQUESTS;
+    }
+
+    pub(crate) fn iter(&self) -> impl Iterator<Item = (bool, &CompletedRequest)> {
+        let idx = self.idx;
+        self.buf.iter().enumerate().filter_map(move |(i, req)| Some((i == idx, req.as_ref()?)))
+    }
+}
diff --git a/crates/ra_lsp_server/src/main_loop/subscriptions.rs b/crates/ra_lsp_server/src/main_loop/subscriptions.rs
index 11bd952d9..470bc1205 100644
--- a/crates/ra_lsp_server/src/main_loop/subscriptions.rs
+++ b/crates/ra_lsp_server/src/main_loop/subscriptions.rs
@@ -1,21 +1,19 @@
 use ra_ide_api::FileId;
 use rustc_hash::FxHashSet;
 
-pub struct Subscriptions {
+#[derive(Default)]
+pub(crate) struct Subscriptions {
     subs: FxHashSet<FileId>,
 }
 
 impl Subscriptions {
-    pub fn new() -> Subscriptions {
-        Subscriptions { subs: FxHashSet::default() }
-    }
-    pub fn add_sub(&mut self, file_id: FileId) {
+    pub(crate) fn add_sub(&mut self, file_id: FileId) {
         self.subs.insert(file_id);
     }
-    pub fn remove_sub(&mut self, file_id: FileId) {
+    pub(crate) fn remove_sub(&mut self, file_id: FileId) {
         self.subs.remove(&file_id);
     }
-    pub fn subscriptions(&self) -> Vec<FileId> {
+    pub(crate) fn subscriptions(&self) -> Vec<FileId> {
         self.subs.iter().cloned().collect()
     }
 }
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/server_world.rs
index 7eb4d3e56..8c7951e13 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/server_world.rs
@@ -1,7 +1,6 @@
 use std::{
     path::{Path, PathBuf},
     sync::Arc,
-    time::Duration,
 };
 
 use lsp_types::Url;
@@ -16,6 +15,7 @@ use failure::{Error, format_err};
 use gen_lsp_server::ErrorCode;
 
 use crate::{
+    main_loop::pending_requests::{CompletedRequest, LatestRequests},
     project_model::ProjectWorkspace,
     vfs_filter::IncludeRustFiles,
     Result,
@@ -29,26 +29,14 @@ 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,
+    pub latest_requests: Arc<RwLock<LatestRequests>>,
 }
 
-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,
+    pub latest_requests: Arc<RwLock<LatestRequests>>,
 }
 
 impl ServerWorldState {
@@ -88,8 +76,7 @@ impl ServerWorldState {
             workspaces: Arc::new(workspaces),
             analysis_host,
             vfs: Arc::new(RwLock::new(vfs)),
-            latest_completed_requests: Default::default(),
-            request_idx: 0,
+            latest_requests: Default::default(),
         }
     }
 
@@ -158,8 +145,7 @@ 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),
+            latest_requests: Arc::clone(&self.latest_requests),
         }
     }
 
@@ -172,13 +158,7 @@ impl ServerWorldState {
     }
 
     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;
+        self.latest_requests.write().record(request)
     }
 }