Add --x-perf-report flag to the dartanalyzer command

pkg/analyzer_cli/lib/src/perf_report.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.
+
+library analyzer_cli.src.perf_report;
+
+import 'dart:convert' show JsonEncoder;
+import 'dart:io' show File, Platform;
+
+import 'package:analyzer/src/generated/utilities_general.dart'
+    show PerformanceTag;
+import 'package:analyzer_cli/src/options.dart' show CommandLineOptions;
+
+const _JSON = const JsonEncoder.withIndent("  ");
+
+String makePerfReport(int startTime, int endTime, CommandLineOptions options) {

[Brian Wilkerson, 2015/12/17 15:05:41]

We should add a version number to the output so that we can easily detect when
the format of the output has changed.

+  int totalTime = endTime - startTime;
+  int otherTime = totalTime;
+
+  var platformJson = <String, dynamic>{
+    'osType': _osType,
+    'dartSdkVersion': Platform.version,
+    'checkedMode': _isCheckedMode,
+  };
+
+  var optionsJson = <String, dynamic>{
+    'dartSdkPath': options.dartSdkPath,
+    'strongMode': options.strongMode,
+    'showPackageWarnings': options.showPackageWarnings,
+    'showSdkWarnings': options.showSdkWarnings,
+    'definedVariables': options.definedVariables,
+    'packageRootPath': options.packageRootPath,
+    'packageConfigPath': options.packageConfigPath,
+    'sourceFiles': options.sourceFiles,
+  };
+
+  // Convert performance tags to JSON representation.
+  var perfTagsJson = <String, dynamic>{};
+  for (PerformanceTag tag in PerformanceTag.all) {
+    if (tag != PerformanceTag.UNKNOWN) {
+      int tagTime = tag.elapsedMs;
+      perfTagsJson[tag.label] = tagTime;
+      otherTime -= tagTime;
+    }
+  }
+  perfTagsJson['other'] = otherTime;
+
+  var json = <String, dynamic>{
+    'platform': platformJson,
+    'options': optionsJson,
+    'totalElapsedTime': totalTime,
+    'performanceTags': perfTagsJson
+  };
+
+  return _JSON.convert(json);
+}
+
+bool _isCheckedMode = () {
+  bool x = true;
+  try {
+    // Trigger an exception if we're in checked mode.
+    x = "" as dynamic;
+    return x != ""; // return false; suppress unused variable warning
+  } catch (e) {
+    return true;
+  }
+}();
+
+String _osType = () {
+  if (Platform.isLinux) {
+    return "linux";
+  } else if (Platform.isMacOS) {
+    return "mac";
+  } else if (Platform.isWindows) {
+    return "windows";
+  } else if (Platform.isAndroid) {
+    return "android";
+  } else {
+    return "unknown";
+  }
+}();