Switch from Arc/RwLock to Rc/RefCell for CodeContextMenu (#22035)

`CodeContextMenu` is always accessed on one thread, so only `Rc`s and
`Rc<RefCell<_>>` are needed. There should be tiny performance benefits
from this. The main benefit of this is that when seeing code accessing a
`RwLock` it would be reasonable to wonder whether it will block. The
only potential downside is the potential for panics due to overlapping
borrows of the RefCells. I think this is an acceptable risk because most
errors of this nature will be local or will be caught by clippy via the
check for holding a RefCell reference over an `await`.

Release Notes:

- N/A

crates/project/src/lsp_store.rs

@@ -52,7 +52,7 @@ use lsp::{
     WillRenameFiles, WorkDoneProgressCancelParams, WorkspaceFolder,
 };
 use node_runtime::read_package_installed_version;
-use parking_lot::{Mutex, RwLock};
+use parking_lot::Mutex;
 use postage::watch;
 use rand::prelude::*;
 
@@ -65,12 +65,14 @@ use smol::channel::Sender;
 use snippet::Snippet;
 use std::{
     any::Any,
+    cell::RefCell,
     cmp::Ordering,
     convert::TryInto,
     ffi::OsStr,
     iter, mem,
     ops::{ControlFlow, Range},
     path::{self, Path, PathBuf},
+    rc::Rc,
     str,
     sync::Arc,
     time::{Duration, Instant},
@@ -4137,7 +4139,7 @@ impl LspStore {
         &self,
         buffer: Model<Buffer>,
         completion_indices: Vec<usize>,
-        completions: Arc<RwLock<Box<[Completion]>>>,
+        completions: Rc<RefCell<Box<[Completion]>>>,
         cx: &mut ModelContext<Self>,
     ) -> Task<Result<bool>> {
         let client = self.upstream_client();
@@ -4151,8 +4153,8 @@ impl LspStore {
             if let Some((client, project_id)) = client {
                 for completion_index in completion_indices {
                     let (server_id, completion) = {
-                        let completions_guard = completions.read();
-                        let completion = &completions_guard[completion_index];
+                        let completions = completions.borrow_mut();
+                        let completion = &completions[completion_index];
                         did_resolve = true;
                         let server_id = completion.server_id;
                         let completion = completion.lsp_completion.clone();
@@ -4175,8 +4177,8 @@ impl LspStore {
             } else {
                 for completion_index in completion_indices {
                     let (server_id, completion) = {
-                        let completions_guard = completions.read();
-                        let completion = &completions_guard[completion_index];
+                        let completions = completions.borrow_mut();
+                        let completion = &completions[completion_index];
                         let server_id = completion.server_id;
                         let completion = completion.lsp_completion.clone();
 
@@ -4218,7 +4220,7 @@ impl LspStore {
         server: Arc<lsp::LanguageServer>,
         adapter: Arc<CachedLspAdapter>,
         snapshot: &BufferSnapshot,
-        completions: Arc<RwLock<Box<[Completion]>>>,
+        completions: Rc<RefCell<Box<[Completion]>>>,
         completion_index: usize,
         completion: lsp::CompletionItem,
         language_registry: Arc<LanguageRegistry>,
@@ -4246,11 +4248,11 @@ impl LspStore {
             )
             .await;
 
-            let mut completions = completions.write();
+            let mut completions = completions.borrow_mut();
             let completion = &mut completions[completion_index];
             completion.documentation = Some(documentation);
         } else {
-            let mut completions = completions.write();
+            let mut completions = completions.borrow_mut();
             let completion = &mut completions[completion_index];
             completion.documentation = Some(Documentation::Undocumented);
         }
@@ -4265,7 +4267,7 @@ impl LspStore {
             if let Some((old_range, mut new_text)) = edit {
                 LineEnding::normalize(&mut new_text);
 
-                let mut completions = completions.write();
+                let mut completions = completions.borrow_mut();
                 let completion = &mut completions[completion_index];
 
                 completion.new_text = new_text;
@@ -4274,7 +4276,7 @@ impl LspStore {
         }
         if completion_item.insert_text_format == Some(InsertTextFormat::SNIPPET) {
             // vtsls might change the type of completion after resolution.
-            let mut completions = completions.write();
+            let mut completions = completions.borrow_mut();
             let completion = &mut completions[completion_index];
             if completion_item.insert_text_format != completion.lsp_completion.insert_text_format {
                 completion.lsp_completion.insert_text_format = completion_item.insert_text_format;
@@ -4300,7 +4302,7 @@ impl LspStore {
             )
         });
 
-        let mut completions = completions.write();
+        let mut completions = completions.borrow_mut();
         let completion = &mut completions[completion_index];
         completion.lsp_completion = completion_item;
         if completion.label.filter_text() == new_label.filter_text() {
@@ -4322,7 +4324,7 @@ impl LspStore {
         project_id: u64,
         server_id: LanguageServerId,
         buffer_id: BufferId,
-        completions: Arc<RwLock<Box<[Completion]>>>,
+        completions: Rc<RefCell<Box<[Completion]>>>,
         completion_index: usize,
         completion: lsp::CompletionItem,
         client: AnyProtoClient,
@@ -4360,7 +4362,7 @@ impl LspStore {
             Documentation::MultiLinePlainText(response.documentation)
         };
 
-        let mut completions = completions.write();
+        let mut completions = completions.borrow_mut();
         let completion = &mut completions[completion_index];
         completion.documentation = Some(documentation);
         completion.lsp_completion = lsp_completion;

crates/project/src/project.rs

@@ -57,7 +57,7 @@ use lsp::{
 };
 use lsp_command::*;
 use node_runtime::NodeRuntime;
-use parking_lot::{Mutex, RwLock};
+use parking_lot::Mutex;
 pub use prettier_store::PrettierStore;
 use project_settings::{ProjectSettings, SettingsObserver, SettingsObserverEvent};
 use remote::{SshConnectionOptions, SshRemoteClient};
@@ -73,8 +73,10 @@ use snippet::Snippet;
 use snippet_provider::SnippetProvider;
 use std::{
     borrow::Cow,
+    cell::RefCell,
     ops::Range,
     path::{Component, Path, PathBuf},
+    rc::Rc,
     str,
     sync::Arc,
     time::Duration,
@@ -2872,7 +2874,7 @@ impl Project {
         &self,
         buffer: Model<Buffer>,
         completion_indices: Vec<usize>,
-        completions: Arc<RwLock<Box<[Completion]>>>,
+        completions: Rc<RefCell<Box<[Completion]>>>,
         cx: &mut ModelContext<Self>,
     ) -> Task<Result<bool>> {
         self.lsp_store.update(cx, |lsp_store, cx| {