Add linter by default for polymer's pub-build, also cleans up the linter code.

pkg/polymer/lib/src/build/linter.dart

 // Copyright (c) 2013, 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.
 
 /**
  * Logic to validate that developers are correctly using Polymer constructs.
  * This is mainly used to produce warnings for feedback in the editor.
  */
 library polymer.src.build.linter;
 
 import 'dart:io';
 import 'dart:async';
 import 'dart:mirrors';
 import 'dart:convert' show JSON;
 
 import 'package:barback/barback.dart';
 import 'package:html5lib/dom.dart';
 import 'package:html5lib/dom_parsing.dart';
 import 'package:source_maps/span.dart';
 
 import 'common.dart';
 import 'utils.dart';
 
-typedef String MessageFormatter(String kind, String message, Span span);
-
 /**
  * A linter that checks for common Polymer errors and produces warnings to
  * show on the editor or the command line. Leaves sources unchanged, but creates
  * a new asset containing all the warnings.
  */
 class Linter extends Transformer with PolymerTransformer {
   final TransformOptions options;
 
   /** Only run on .html files. */
   final String allowedExtensions = '.html';
 
-  final MessageFormatter _formatter;
-
-  Linter(this.options, [this._formatter]);
+  Linter(this.options);
 
   Future apply(Transform transform) {
-    var wrapper = new _LoggerInterceptor(transform, _formatter);
     var seen = new Set<AssetId>();
     var primary = transform.primaryInput;
     var id = primary.id;
-    wrapper.addOutput(primary); // this phase is analysis only
+    transform.addOutput(primary); // this phase is analysis only
     seen.add(id);
-    return readPrimaryAsHtml(wrapper).then((document) {
-      return _collectElements(document, id, wrapper, seen).then((elements) {
+    return readPrimaryAsHtml(transform).then((document) {
+      return _collectElements(document, id, transform, seen).then((elements) {
         bool isEntrypoint = options.isHtmlEntryPoint(id);
-        new _LinterVisitor(wrapper, elements, isEntrypoint).run(document);
-        var messagesId = id.addExtension('.messages');
-        wrapper.addOutput(new Asset.fromString(messagesId,
-            wrapper._messages.join('\n')));
+        new _LinterVisitor(transform.logger, elements, isEntrypoint)
+            .run(document);
       });
     });
   }
 
   /**
    * Collect into [elements] any data about each polymer-element defined in
    * [document] or any of it's imports, unless they have already been [seen].
    * Elements are added in the order they appear, transitive imports are added
    * first.
    */
@@ skipping 57 matching lines @@
         logger.warning('duplicate definition for custom tag "$name" '
           ' (second definition).', span: span);
         continue;
       }
 
       elements[name] = new _ElementSummary(name, extendsTag, tag.sourceSpan);
     }
   }
 }
 
-/** A proxy of [Transform] that returns a different logger. */
-// TODO(sigmund): get rid of this when barback supports a better way to log
-// messages without printing them.
-class _LoggerInterceptor implements Transform, TransformLogger {
-  final Transform _original;
-  final List<String> _messages = [];
-  final MessageFormatter _formatter;
-
-  _LoggerInterceptor(this._original, MessageFormatter formatter)
-      : _formatter = formatter == null ? consoleFormatter : formatter;
-
-  TransformLogger get logger => this;
-
-  noSuchMethod(Invocation m) => reflect(_original).delegate(m);
-
-  // form TransformLogger:
-  void warning(String message, {AssetId asset, Span span})
-      => _write('warning', message, span);
-
-  void error(String message, {AssetId asset, Span span})
-      => _write('error', message, span);
-
-  void _write(String kind, String message, Span span) {
-    _messages.add(_formatter(kind, message, span));
-  }
-}
-
-/**
- * Formatter that generates messages using a format that can be parsed
- * by tools, such as the Dart Editor, for reporting error messages.
- */
-String jsonFormatter(String kind, String message, Span span) {
-  return JSON.encode((span == null)
-      ? [{'method': 'warning', 'params': {'message': message}}]
-      : [{'method': kind,
-          'params': {
-            'file': span.sourceUrl,
-            'message': message,
-            'line': span.start.line + 1,
-            'charStart': span.start.offset,
-            'charEnd': span.end.offset,
-          }}]);
-}
-
-/**
- * Formatter that generates messages that are easy to read on the console (used
- * by default).
- */
-String consoleFormatter(String kind, String message, Span span) {
-  var useColors = stdioType(stdout) == StdioType.TERMINAL;
-  var levelColor = (kind == 'error') ? _RED_COLOR : _MAGENTA_COLOR;
-  var output = new StringBuffer();
-  if (useColors) output.write(levelColor);
-  output..write(kind)..write(' ');
-  if (useColors) output.write(_NO_COLOR);
-  if (span == null) {
-    output.write(message);
-  } else {
-    output.write(span.getLocationMessage(message,
-          useColors: useColors,
-          color: levelColor));
-  }
-  return output.toString();
-}
 
 /**
  * Information needed about other polymer-element tags in order to validate
  * how they are used and extended.
  *
  * Note: these are only created for polymer-element, because pure custom
  * elements don't have a declarative form.
  */
 class _ElementSummary {
   final String tagName;
@@ skipping 304 matching lines @@
 
 /**
  * Returns true if this is a valid custom element name. See:
  * <https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/custom/index.html#dfn-custom-element-name>
  */
 bool _isCustomTag(String name) {
   if (name == null || !name.contains('-')) return false;
   return !_invalidTagNames.containsKey(name);
 }
 
-const String _RED_COLOR = '\u001b[31m';
-const String _MAGENTA_COLOR = '\u001b[35m';
-const String _NO_COLOR = '\u001b[0m';
-
 const String USE_INIT_DART =
     'To run a polymer application, you need to call "initPolymer". You can '
     'either include a generic script tag that does this for you:'
     '\'<script type="application/dart">export "package:polymer/init.dart";'
     '</script>\' or add your own script tag and call that function. '
     'Make sure the script tag is placed after all HTML imports.';
 
 const String BOOT_JS_DEPRECATED =
     '"boot.js" is now deprecated. Instead, you can initialize your polymer '
     'application by calling "initPolymer()" in your main. If you don\'t have a '
     'main, then you can include our generic main by adding the following '
     'script tag to your page: \'<script type="application/dart">export '
     '"package:polymer/init.dart";</script>\'. Additionally you need to '
     'include: \'<script src="packages/browser/dart.js"></script>\' in the page '
     'too. Make sure these script tags come after all HTML imports.';