Add IsolateRunner as a helper around Isolate.

example/http-server.dart

Index: example/http-server.dart
diff --git a/example/http-server.dart b/example/http-server.dart
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--- /dev/null
+++ b/example/http-server.dart
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+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library dart.pkg.isolate.sample.httpserver;
+
+import "dart:io";
+import "dart:async";
+import "dart:isolate";
+import "package:isolate/isolaterunner.dart";
+import "package:isolate/runner.dart";
+import "package:isolate/ports.dart";
+
+typedef Future RemoteStop();
+
+Future<RemoteStop> runHttpServer(
+    Runner runner, ServerSocket socket, HttpListener listener) {
+  return runner.run(_startHttpServer, new List(2)..[0] = socket.reference
+                                                 ..[1] = listener)
+               .then((SendPort stopPort) => () => _sendStop(stopPort));
+}
+
+Future _sendStop(SendPort stopPort) {
+  return singleResponseFuture(stopPort.send);
+}
+
+Future<SendPort> _startHttpServer(List args) {
+  ServerSocketReference ref = args[0];
+  HttpListener listener = args[1];
+  return ref.create().then((socket) {
+    return listener.start(new HttpServer.listenOn(socket));
+  }).then((_) {
+    return singleCallbackPort((SendPort resultPort) {
+      sendFutureResult(new Future.sync(listener.stop), resultPort);
+    });
+  });
+}
+
+/**
+ * An [HttpRequest] handler setup. Gets called when with the server, and
+ * is told when to stop listening.
+ *
+ * These callbacks allow the listener to set up handlers for HTTP requests.
+ * The object should be sendable to an equivalent isolate.
+ */
+abstract class HttpListener {
+  Future start(HttpServer server);
+  Future stop();
+}
+
+/**
+ * An [HttpListener] that sets itself up as an echo server.
+ *
+ * Returns the message content plus an ID describing the isolate that
+ * handled the request.
+ */
+class EchoHttpListener implements HttpListener {
+  StreamSubscription _subscription;
+  static int _id = new Object().hashCode;
+  SendPort _counter;
+
+  EchoHttpListener(this._counter);
+
+  start(HttpServer server) {
+    print("Starting isolate $_id");
+    _subscription = server.listen((HttpRequest request) {
+      request.response.addStream(request).then((_) {
+        _counter.send(null);
+        print("Request to $_id");
+        request.response.write("#$_id\n");
+        var t0 = new DateTime.now().add(new Duration(seconds:2));
+        while (new DateTime.now().isBefore(t0));
+        print("Response from $_id");
+        request.response.close();
+      });
+    });
+  }
+
+  stop() {
+    print("Stopping isolate $_id");
+    _subscription.cancel();
+    _subscription = null;
+  }
+}
+
+main(args) {
+  int port = 0;
+  if (args.length > 0) {
+    port = int.parse(args[0]);
+  }
+  RawReceivePort counter = new RawReceivePort();
+  HttpListener listener = new EchoHttpListener(counter.sendPort);
+  ServerSocket
+    .bind(InternetAddress.ANY_IP_V6, port)
+    .then((ServerSocket socket) {
+      port = socket.port;
+      return Future.wait(new Iterable.generate(5, (_) => IsolateRunner.spawn()),
+                         cleanUp: (isolate) { isolate.close(); })
+                   .then((List<IsolateRunner> isolates) {
+                     return Future.wait(isolates.map((IsolateRunner isolate) {
+                       return runHttpServer(isolate, socket, listener);
+                     }), cleanUp: (server) { server.stop(); });
+                   })
+                   .then((stoppers) {
+                     socket.close();
+                     int count = 25;
+                     counter.handler = (_) {
+                       count--;
+                       if (count == 0) {
+                         stoppers.forEach((f) => f());
+                         counter.close();
+                       }
+                     };
+                     print("Server listening on port $port for 25 requests");
+                     print("Test with:");
+                     print("  ab -c10 -n 25  http://localhost:$port/");
+                   });
+  });
+}