playground: minor improvements

frontend/tools/pyodide-worker.ts

@@ -25,6 +25,9 @@ export type MessageEventDataIn = {
     id: number;
     path: string;
     content: string;
+} | {
+    type: 'makeSnapshot';
+    id: number;
 }
 
 self.onmessage = async (event: MessageEvent<MessageEventDataIn>) => {
@@ -64,6 +67,15 @@ self.onmessage = async (event: MessageEvent<MessageEventDataIn>) => {
         } catch (error: any) {
             self.postMessage({id: event.data.id, error: error.message});
         }
+    } else if (event.data.type === 'makeSnapshot') {
+        // Take a snapshot of the current Pyodide filesystem.
+        const pyodide = await pyodideReadyPromise;
+        try {
+            const snapshot = pyodide.makeMemorySnapshot();
+            self.postMessage({id: event.data.id, result: snapshot});
+        } catch (error: any) {
+            self.postMessage({id: event.data.id, error: error.message});
+        }
     } else {
         console.error("Unknown message type:", (event.data as any)?.type);
         self.postMessage({id: (event.data as any)?.id, error: "Unknown message type: " + (event.data as any)?.type});