2 files changed, 56 insertions, 43 deletions

diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index 8f41937dc..8a7c53d2c 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -2,7 +2,7 @@ mod handlers;
 mod subscriptions;
 pub(crate) mod pending_requests;
 
-use std::{fmt, path::PathBuf, sync::Arc, time::Instant, any::TypeId};
+use std::{fmt, path::PathBuf, sync::Arc, time::Instant};
 
 use crossbeam_channel::{select, unbounded, Receiver, RecvError, Sender};
 use failure::{bail, format_err};
@@ -219,22 +219,15 @@ fn main_loop_inner(
                         Some(req) => req,
                         None => return Ok(()),
                     };
-                    match req.cast::<req::CollectGarbage>() {
-                        Ok((id, ())) => {
-                            state.collect_garbage();
-                            let resp = RawResponse::ok::<req::CollectGarbage>(id, &());
-                            msg_sender.send(resp.into()).unwrap()
-                        }
-                        Err(req) => on_request(
-                            state,
-                            pending_requests,
-                            pool,
-                            &task_sender,
-                            msg_sender,
-                            loop_start,
-                            req,
-                        )?,
-                    }
+                    on_request(
+                        state,
+                        pending_requests,
+                        pool,
+                        &task_sender,
+                        msg_sender,
+                        loop_start,
+                        req,
+                    )?
                 }
                 RawMessage::Notification(not) => {
                     on_notification(msg_sender, state, pending_requests, subs, not)?;
@@ -322,6 +315,7 @@ fn on_request(
         request_received,
     };
     pool_dispatcher
+        .on_sync::<req::CollectGarbage>(|state, ()| Ok(state.collect_garbage()))?
         .on::<req::AnalyzerStatus>(handlers::handle_analyzer_status)?
         .on::<req::SyntaxTree>(handlers::handle_syntax_tree)?
         .on::<req::ExtendSelection>(handlers::handle_extend_selection)?
@@ -434,37 +428,39 @@ struct PoolDispatcher<'a> {
 }
 
 impl<'a> PoolDispatcher<'a> {
-    fn on<R>(&mut self, f: fn(ServerWorld, R::Params) -> Result<R::Result>) -> Result<&mut Self>
+    fn on_sync<R>(
+        &mut self,
+        f: fn(&mut ServerWorldState, R::Params) -> Result<R::Result>,
+    ) -> Result<&mut Self>
     where
         R: req::Request + 'static,
         R::Params: DeserializeOwned + Send + 'static,
         R::Result: Serialize + 'static,
     {
-        let req = match self.req.take() {
-            None => return Ok(self),
-            Some(req) => req,
-        };
-        let (id, params) = match req.cast::<R>() {
-            Ok(it) => it,
-            Err(req) => {
-                self.req = Some(req);
+        let (id, params) = match self.parse::<R>() {
+            Some(it) => it,
+            None => {
                 return Ok(self);
             }
         };
-        self.pending_requests.start(PendingRequest {
-            id,
-            method: R::METHOD.to_string(),
-            received: self.request_received,
-        });
+        let result = f(self.world, params);
+        let task = result_to_task::<R>(id, result);
+        on_task(task, self.msg_sender, self.pending_requests, self.world);
+        Ok(self)
+    }
 
-        // Real time requests block user typing, so we should react quickly to them.
-        // Currently this means that we try to cancel background jobs if we don't have
-        // a spare thread.
-        let is_real_time = TypeId::of::<R>() == TypeId::of::<req::JoinLines>()
-            || TypeId::of::<R>() == TypeId::of::<req::OnEnter>();
-        if self.pool.queued_count() > 0 && is_real_time {
-            self.world.cancel_requests();
-        }
+    fn on<R>(&mut self, f: fn(ServerWorld, R::Params) -> Result<R::Result>) -> Result<&mut Self>
+    where
+        R: req::Request + 'static,
+        R::Params: DeserializeOwned + Send + 'static,
+        R::Result: Serialize + 'static,
+    {
+        let (id, params) = match self.parse::<R>() {
+            Some(it) => it,
+            None => {
+                return Ok(self);
+            }
+        };
 
         self.pool.execute({
             let world = self.world.snapshot();
@@ -479,6 +475,27 @@ impl<'a> PoolDispatcher<'a> {
         Ok(self)
     }
 
+    fn parse<R>(&mut self) -> Option<(u64, R::Params)>
+    where
+        R: req::Request + 'static,
+        R::Params: DeserializeOwned + Send + 'static,
+    {
+        let req = self.req.take()?;
+        let (id, params) = match req.cast::<R>() {
+            Ok(it) => it,
+            Err(req) => {
+                self.req = Some(req);
+                return None;
+            }
+        };
+        self.pending_requests.start(PendingRequest {
+            id,
+            method: R::METHOD.to_string(),
+            received: self.request_received,
+        });
+        Some((id, params))
+    }
+
     fn finish(&mut self) {
         match self.req.take() {
             None => (),
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/server_world.rs
index 8c7951e13..6076a6cd6 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/server_world.rs
@@ -136,10 +136,6 @@ impl ServerWorldState {
         self.analysis_host.apply_change(change);
     }
 
-    pub fn cancel_requests(&mut self) {
-        self.analysis_host.apply_change(AnalysisChange::new());
-    }
-
     pub fn snapshot(&self) -> ServerWorld {
         ServerWorld {
             workspaces: Arc::clone(&self.workspaces),