Add dart_messages package.

R=johnniwinther@google.com, sigmund@google.com

Review URL: https://codereview.chromium.org/1514333002 .

pkg/compiler/lib/src/diagnostics/messages.dart

@@ -4,13 +4,14 @@
 
 library dart2js.messages;
 
+import 'package:dart_messages/shared_messages.dart' as shared_messages;
+
 import '../tokens/token.dart' show ErrorToken, Token;
 
 import 'invariant.dart' show invariant;
 import 'spannable.dart' show CURRENT_ELEMENT_SPANNABLE;
 
 import 'dart2js_messages.dart' as dart2js_messages;
-import 'shared_messages.dart' as shared_messages;
 
 /// Keys for the [MessageTemplate]s.
 enum MessageKind {

pkg/compiler/pubspec.yaml

@@ -17,6 +17,8 @@ dependencies:
     path: ../../../../dart2js_info
   lookup_map:
     path: ../lookup_map
+  dart_messages:
+    path: ../dart_messages
 
 # Uncomment if running gclient, so you can depend directly on the downloaded
 # versions of dart2js's transitive dependencies:

pkg/dart_messages/bin/json_converter.dart

@@ -0,0 +1,20 @@
+// 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.
+
+import 'dart:convert';
+import 'dart:io';
+
+import '../lib/shared_messages.dart' as shared_messages;
+
+/// Translates the shared messages in `../lib/shared_messages` to JSON and
+/// emits it into `../lib/shared_messages.json`.
+void main() {
+  var input = shared_messages.MESSAGES;
+  var outPath =
+      Platform.script.resolve('../lib/shared_messages.json').toFilePath();
+  print("Input: ${input.length} entries");
+  print("Output: $outPath");
+  new File(outPath).writeAsStringSync(JSON.encode(shared_messages.MESSAGES));
+  print("Done");
+}

pkg/dart_messages/bin/message_id.dart

@@ -0,0 +1,35 @@
+// 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.
+
+import 'dart:math' as math;
+
+import '../lib/shared_messages.dart' as shared_messages;
+
+math.Random random = new math.Random();
+
+const idLength = 6;
+final $A = "A".codeUnitAt(0);
+final $Z = "Z".codeUnitAt(0);
+
+String computeId() {
+  List charCodes = [];
+  for (int i = 0; i < idLength; i++) {
+    charCodes.add($A + random.nextInt($Z - $A));
+  }
+  return new String.fromCharCodes(charCodes);
+}
+
+/// Computes a random message ID that hasn't been used before.
+void main() {
+  var usedIds =
+      shared_messages.MESSAGES.values.map((entry) => entry['id']).toSet();
+
+  print("${usedIds.length} existing ids");
+
+  var newId;
+  do {
+    newId = computeId();
+  } while (!usedIds.contains(newId));
+  print("Available id: $newId");
+}

pkg/dart_messages/lib/shared_messages.dart

@@ -2,10 +2,11 @@
 // 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.
 
-// This file is parsed by JavaScript and must not use fancy Dart constructs.
-// It can contain JSON like constructs and "//" comments (but not "/*" "*/").
-// It must have one assignment (`final MESSAGES =`).
-// All strings must be raw strings.
+// An update to this file must be followed by regenerating the corresponding
+// json file. Use `json_converter.dart` in the bin directory.
+//
+// Every message in this file must have an id. Use `message_id.dart` in the
+// bin directory to generate a fresh one.
 
 // The messages in this file should meet the following guide lines:
 //
@@ -57,5 +58,5 @@
 // 1. what is wrong, 2. why is it wrong, 3. how do I fix it. However, we
 // combine the first two in [template] and the last in [howToFix].
 
-final MESSAGES = {
+final Map<String, Map> MESSAGES = {
 };

pkg/dart_messages/lib/shared_messages.json

@@ -0,0 +1 @@
+{}

pkg/dart_messages/pubspec.yaml

@@ -0,0 +1,4 @@
+# This package is not intended to be published.
+name: dart_messages
+#version: do-not-upload
+dependencies:

pkg/dart_messages/test/dart_messages_test.dart

@@ -0,0 +1,40 @@
+// 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.
+
+import 'dart:convert';
+import 'dart:io';
+
+import '../lib/shared_messages.dart';
+
+void testJsonIsUpdated() {
+  var packageRoot = Platform.packageRoot;
+  if (packageRoot == null || packageRoot == "") {
+    throw new UnsupportedError("This test requires a package root.");
+  }
+  var jsonUri =
+      Uri.parse(packageRoot).resolve('dart_messages/shared_messages.json');
+  var jsonPath = jsonUri.toFilePath();
+  var content = new File(jsonPath).readAsStringSync();
+  if (JSON.encode(MESSAGES) != content) {
+    print("The content of the Dart messages and the corresponding JSON file");
+    print("is not the same.");
+    print("Please run bin/json_converter to update the JSON file.");
+    throw "Content is not the same";
+  }
+}
+
+void testIdsAreUnique() {
+  var usedIds = new Set();
+  for (var entry in MESSAGES.values) {
+    var id = entry['id'];
+    if (!usedIds.add(id)) {
+      throw "Id appears twice: $id";
+    }
+  }
+}
+
+void main() {
+  testJsonIsUpdated();
+  testIdsAreUnique();
+}