Setting up benchmarks and perf utilities

test/perf/update_json.dart

+#!/usr/bin/env dart
+// Copyright (c) 2012, 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.
+
+/**
+ * A simple script that updates a target json file with the new values from
+ * another json file.
+ */
+library test.perf.update_json;
+
+import 'dart:io';
+import 'dart:json';
+import 'dart:math' as math;
+
+main() {
+  var args = new Options().arguments;
+  if (args.length < 2) {
+    print('update_json.dart: A simple script that updates a target json file '
+          'with the new values from another json file. ');
+    print('usage: update.dart from.json to.json');
+    exit(1);
+  }
+
+  var path1 = args[0];
+  var path2 = args[1];
+  var file1 = new File(path1).readAsStringSync();
+  var file2 = new File(path2).readAsStringSync();
+
+  var results = [];
+  var map1 = JSON.parse(file1);
+  var map2 = JSON.parse(file2);
+
+  for (var key in map1.keys) {
+    if (map1[key] != null) {
+      map2[key] = map1[key];
+    }
+  }
+
+  print('updating $path2...');
+  _writeFile(path2, JSON.stringify(map2));
+}
+
+Future _writeFile(String path, String text) {
+  return new File(path).open(FileMode.WRITE)
+      .chain((file) => file.writeString(text))
+      .chain((file) => file.close());
+}