From 66ed821e18eadd3930a8621095c90b142763d517 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Wed, 6 Jan 2021 15:46:31 +0300
Subject: [PATCH] Speed up snapshoting

Config can be fairly big, no need to deep clone it frequently
---
 crates/rust-analyzer/src/global_state.rs | 8 ++++----
 crates/rust-analyzer/src/main_loop.rs    | 2 +-
 crates/rust-analyzer/src/reload.rs       | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index 19ab4d596a4..1f6bf1c8cbb 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -67,7 +67,7 @@ pub(crate) struct GlobalState {
     pub(crate) flycheck: Vec<FlycheckHandle>,
     pub(crate) flycheck_sender: Sender<flycheck::Message>,
     pub(crate) flycheck_receiver: Receiver<flycheck::Message>,
-    pub(crate) config: Config,
+    pub(crate) config: Arc<Config>,
     pub(crate) analysis_host: AnalysisHost,
     pub(crate) diagnostics: DiagnosticCollection,
     pub(crate) mem_docs: FxHashMap<VfsPath, DocumentData>,
@@ -83,7 +83,7 @@ pub(crate) struct GlobalState {
 
 /// An immutable snapshot of the world's state at a point in time.
 pub(crate) struct GlobalStateSnapshot {
-    pub(crate) config: Config,
+    pub(crate) config: Arc<Config>,
     pub(crate) analysis: Analysis,
     pub(crate) check_fixes: CheckFixes,
     pub(crate) latest_requests: Arc<RwLock<LatestRequests>>,
@@ -119,7 +119,7 @@ pub(crate) fn new(sender: Sender<lsp_server::Message>, config: Config) -> Global
             flycheck: Vec::new(),
             flycheck_sender,
             flycheck_receiver,
-            config,
+            config: Arc::new(config),
             analysis_host,
             diagnostics: Default::default(),
             mem_docs: FxHashMap::default(),
@@ -184,7 +184,7 @@ pub(crate) fn process_changes(&mut self) -> bool {
 
     pub(crate) fn snapshot(&self) -> GlobalStateSnapshot {
         GlobalStateSnapshot {
-            config: self.config.clone(),
+            config: Arc::clone(&self.config),
             workspaces: Arc::clone(&self.workspaces),
             analysis: self.analysis_host.analysis(),
             vfs: Arc::clone(&self.vfs),
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 53f9546b869..7ac6acf708d 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -609,7 +609,7 @@ fn on_notification(&mut self, not: Notification) -> Result<()> {
                                 if let Some(json) = configs.get_mut(0) {
                                     // Note that json can be null according to the spec if the client can't
                                     // provide a configuration. This is handled in Config::update below.
-                                    let mut config = this.config.clone();
+                                    let mut config = Config::clone(&*this.config);
                                     config.update(json.take());
                                     this.update_configuration(config);
                                 }
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index 51c24e966d6..76b50931ad6 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -18,7 +18,7 @@
 impl GlobalState {
     pub(crate) fn update_configuration(&mut self, config: Config) {
         let _p = profile::span("GlobalState::update_configuration");
-        let old_config = mem::replace(&mut self.config, config);
+        let old_config = mem::replace(&mut self.config, Arc::new(config));
         if self.config.lru_capacity() != old_config.lru_capacity() {
             self.analysis_host.update_lru_capacity(self.config.lru_capacity());
         }