Encapsulate inlay hints activation

editors/code/src/inlay_hints.ts

@@ -1,6 +1,42 @@
 import * as vscode from 'vscode';
 import * as lc from 'vscode-languageclient';
 import { Server } from './server';
+import { Ctx } from './ctx';
+
+export function activateInlayHints(ctx: Ctx) {
+    const hintsUpdater = new HintsUpdater();
+    hintsUpdater.refreshHintsForVisibleEditors().then(() => {
+        // vscode may ignore top level hintsUpdater.refreshHintsForVisibleEditors()
+        // so update the hints once when the focus changes to guarantee their presence
+        let editorChangeDisposable: vscode.Disposable | null = null;
+        editorChangeDisposable = vscode.window.onDidChangeActiveTextEditor(
+            _ => {
+                if (editorChangeDisposable !== null) {
+                    editorChangeDisposable.dispose();
+                }
+                return hintsUpdater.refreshHintsForVisibleEditors();
+            },
+        );
+
+        ctx.pushCleanup(
+            vscode.window.onDidChangeVisibleTextEditors(_ =>
+                hintsUpdater.refreshHintsForVisibleEditors(),
+            ),
+        );
+        ctx.pushCleanup(
+            vscode.workspace.onDidChangeTextDocument(e =>
+                hintsUpdater.refreshHintsForVisibleEditors(e),
+            ),
+        );
+        ctx.pushCleanup(
+            vscode.workspace.onDidChangeConfiguration(_ =>
+                hintsUpdater.toggleHintsDisplay(
+                    Server.config.displayInlayHints,
+                ),
+            ),
+        );
+    });
+}
 
 interface InlayHintsParams {
     textDocument: lc.TextDocumentIdentifier;
@@ -18,7 +54,7 @@ const typeHintDecorationType = vscode.window.createTextEditorDecorationType({
     },
 });
 
-export class HintsUpdater {
+class HintsUpdater {
     private displayHints = true;
 
     public async toggleHintsDisplay(displayHints: boolean): Promise<void> {