Service isolate rework take 2

runtime/bin/vmservice/loader.dart

+// 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.
+
+part of vmservice_io;
+
+var _httpClient;
+
+void _loadHttp(sendPort, uri) {
+  if (_httpClient == null) {
+    _httpClient = new HttpClient()..maxConnectionsPerHost = 6;
+  }
+  _httpClient.getUrl(uri)
+    .then((HttpClientRequest request) => request.close())
+    .then((HttpClientResponse response) {
+      var builder = new BytesBuilder(copy: false);
+      response.listen(
+          builder.add,
+          onDone: () {
+            if (response.statusCode != 200) {
+              var msg = 'Failure getting $uri: '
+                        '${response.statusCode} ${response.reasonPhrase}';
+              sendPort.send(msg);
+            } else {
+              sendPort.send(builder.takeBytes());
+            }
+          },
+          onError: (e) {
+            sendPort.send(e.toString());
+          });
+    })
+    .catchError((e) {
+      sendPort.send(e.toString());
+    });
+  // It's just here to push an event on the event loop so that we invoke the
+  // scheduled microtasks.
+  Timer.run(() {});
+}
+
+void _loadFile(sendPort, path) {
+  var sourceFile = new File(path);
+  sourceFile.readAsBytes().then((data) {
+    sendPort.send(data);
+  },
+  onError: (e) {
+    sendPort.send(e.toString());
+  });
+}
+
+_processLoadRequest(request) {
+  var sp = request[0];
+  var uri = Uri.parse(request[1]);
+  if (uri.scheme == 'file') {
+    _loadFile(sp, uri.toFilePath());
+  } else if ((uri.scheme == 'http') || (uri.scheme == 'https')) {
+    _loadHttp(sp, uri);
+  } else {
+    sp.send('Unknown scheme for $uri');
+  }
+}