From 1cb6692295b627c44bafdf1ce729e2d9dd7736a6 Mon Sep 17 00:00:00 2001
From: Carlos Gilberto Avalos <carlos.g.avalos@gmail.com>
Date: Tue, 27 Jun 2023 19:33:44 -0400
Subject: [PATCH] Deactivate VSCode extension asynchronously

When using HLSL Tools on MacOS, orphaned ShaderTools.LanguageServer
processes will accumulate, wasting memory. This happens after closing
and opening VSCode repeatedly. This does not appear to happen on Windows
in my experience.

https://github.com/microsoft/vscode/issues/35196#issuecomment-334399348

The above GitHub issue details other developers' experiences with the
same problem. The solution presented by dbaeumer was to return a
`Promise` from an exported `deactivate()`.

https://code.visualstudio.com/api/references/activation-events#Start-up

This is confirmed by the above VSCode docs. Extensions with asynchronous
cleanup processes must return a `Promise` from their `deactivate()`. As
`LanguageServerClient.stop()` returns a `Promise`, we are obligated to
return it when deactivating.
---
 src/ShaderTools.VSCode/src/main.ts    | 4 ++++
 src/ShaderTools.VSCode/src/session.ts | 8 ++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/ShaderTools.VSCode/src/main.ts b/src/ShaderTools.VSCode/src/main.ts
index 151064a1..a208b7fa 100644
--- a/src/ShaderTools.VSCode/src/main.ts
+++ b/src/ShaderTools.VSCode/src/main.ts
@@ -8,4 +8,8 @@ var sessionManager: SessionManager = undefined;
 export function activate(context: vscode.ExtensionContext): void {
     context.subscriptions.push(sessionManager = new SessionManager());
     sessionManager.start();
+}
+
+export function deactivate(): Promise<void> {
+    return sessionManager.stop();
 }
\ No newline at end of file
diff --git a/src/ShaderTools.VSCode/src/session.ts b/src/ShaderTools.VSCode/src/session.ts
index 9836c679..f464ab15 100644
--- a/src/ShaderTools.VSCode/src/session.ts
+++ b/src/ShaderTools.VSCode/src/session.ts
@@ -35,7 +35,7 @@ export class SessionManager {
         this.startEditorServices();
     }
 
-    public stop() {
+    public stop(): Promise<void> {
         if (this.sessionStatus === SessionStatus.Failed) {
             // Before moving further, clear out the client and process if
             // the process is already dead (i.e. it crashed)
@@ -44,13 +44,17 @@ export class SessionManager {
 
         this.sessionStatus = SessionStatus.Stopping;
 
+        var promise = Promise.resolve();
+
         // Close the language server client
         if (this.languageServerClient !== undefined) {
-            this.languageServerClient.stop();
+            promise = this.languageServerClient.stop();
             this.languageServerClient = undefined;
         }
 
         this.sessionStatus = SessionStatus.NotStarted;
+        
+        return promise;
     }
 
     public dispose() : void {