Merge #2898

2898: Remove RWLock from check watcher. r=matklad a=kiljacken

@matklad mentioned this might be a good idea.

So the general idea is that we don't really need the lock, as we can
just clone the check watcher state when creating a snapshot. We can then
use `Arc::get_mut` to get mutable access to the state from `WorldState`
when needed.

Running with this it seems to improve responsiveness a bit while cargo
is running, but I have no hard numbers to prove it. In any case, a
serialization point less is always better when we're trying to be
responsive.

Co-authored-by: Emil Lauridsen <[email protected]>

2 files changed, 5 insertions, 6 deletions

diff --git a/crates/ra_cargo_watch/src/conv.rs b/crates/ra_cargo_watch/src/conv.rs
index ac0f1d28a..8fba400ae 100644
--- a/crates/ra_cargo_watch/src/conv.rs
+++ b/crates/ra_cargo_watch/src/conv.rs
@@ -117,7 +117,7 @@ fn is_deprecated(rd: &RustDiagnostic) -> bool {
     }
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct SuggestedFix {
     pub title: String,
     pub location: Location,
diff --git a/crates/ra_cargo_watch/src/lib.rs b/crates/ra_cargo_watch/src/lib.rs
index 7f4c9280c..bbe634603 100644
--- a/crates/ra_cargo_watch/src/lib.rs
+++ b/crates/ra_cargo_watch/src/lib.rs
@@ -7,7 +7,6 @@ use lsp_types::{
     Diagnostic, Url, WorkDoneProgress, WorkDoneProgressBegin, WorkDoneProgressEnd,
     WorkDoneProgressReport,
 };
-use parking_lot::RwLock;
 use std::{
     collections::HashMap,
     path::PathBuf,
@@ -38,7 +37,7 @@ pub struct CheckOptions {
 #[derive(Debug)]
 pub struct CheckWatcher {
     pub task_recv: Receiver<CheckTask>,
-    pub state: Arc<RwLock<CheckState>>,
+    pub state: Arc<CheckState>,
     cmd_send: Option<Sender<CheckCommand>>,
     handle: Option<JoinHandle<()>>,
 }
@@ -46,7 +45,7 @@ pub struct CheckWatcher {
 impl CheckWatcher {
     pub fn new(options: &CheckOptions, workspace_root: PathBuf) -> CheckWatcher {
         let options = options.clone();
-        let state = Arc::new(RwLock::new(CheckState::new()));
+        let state = Arc::new(CheckState::new());
 
         let (task_send, task_recv) = unbounded::<CheckTask>();
         let (cmd_send, cmd_recv) = unbounded::<CheckCommand>();
@@ -59,7 +58,7 @@ impl CheckWatcher {
 
     /// Returns a CheckWatcher that doesn't actually do anything
     pub fn dummy() -> CheckWatcher {
-        let state = Arc::new(RwLock::new(CheckState::new()));
+        let state = Arc::new(CheckState::new());
         CheckWatcher { task_recv: never(), cmd_send: None, handle: None, state }
     }
 
@@ -87,7 +86,7 @@ impl std::ops::Drop for CheckWatcher {
     }
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct CheckState {
     diagnostic_collection: HashMap<Url, Vec<Diagnostic>>,
     suggested_fix_collection: HashMap<Url, Vec<SuggestedFix>>,