Add a command to compute memory usage statistics

editors/code/src/commands.ts

@@ -55,6 +55,38 @@ export function analyzerStatus(ctx: Ctx): Cmd {
     };
 }
 
+export function memoryUsage(ctx: Ctx): Cmd {
+    const tdcp = new class implements vscode.TextDocumentContentProvider {
+        readonly uri = vscode.Uri.parse('rust-analyzer-memory://memory');
+        readonly eventEmitter = new vscode.EventEmitter<vscode.Uri>();
+
+        provideTextDocumentContent(_uri: vscode.Uri): vscode.ProviderResult<string> {
+            if (!vscode.window.activeTextEditor) return '';
+
+            return ctx.client.sendRequest(ra.memoryUsage, null).then((mem) => {
+                return 'Per-query memory usage:\n' + mem + '\n(note: database has been cleared)';
+            });
+        }
+
+        get onDidChange(): vscode.Event<vscode.Uri> {
+            return this.eventEmitter.event;
+        }
+    }();
+
+    ctx.pushCleanup(
+        vscode.workspace.registerTextDocumentContentProvider(
+            'rust-analyzer-memory',
+            tdcp,
+        ),
+    );
+
+    return async () => {
+        tdcp.eventEmitter.fire(tdcp.uri);
+        const document = await vscode.workspace.openTextDocument(tdcp.uri);
+        return vscode.window.showTextDocument(document, vscode.ViewColumn.Two, true);
+    };
+}
+
 export function matchingBrace(ctx: Ctx): Cmd {
     return async () => {
         const editor = ctx.activeRustEditor;