Plugin babysteps.

Author: pq

lib/plugin/linter.dart

@@ -0,0 +1,16 @@
+// 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.
+
+/// Support for client code that extends the analysis engine by adding new
+/// lint rules.
+library analyzer.plugin.linter;
+
+import 'package:linter/src/linter.dart';
+import 'package:linter/src/plugin/linter_plugin.dart';
+import 'package:plugin/plugin.dart';
+
+/// The identifier of the extension point that allows plugins to register new
+/// lints. The object used as an extension must implement [LintRule].
+final String LINT_RULE_EXTENSION_POINT_ID = Plugin.join(
+    LinterPlugin.UNIQUE_IDENTIFIER, LinterPlugin.LINT_RULE_EXTENSION_POINT);

lib/src/plugin/linter_plugin.dart

@@ -0,0 +1,78 @@
+// 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 linter.src.plugin.linter_plugin;
+
+import 'package:linter/plugin/linter.dart';
+import 'package:linter/src/linter.dart';
+import 'package:linter/src/rules/camel_case_types.dart';
+import 'package:linter/src/rules/constant_identifier_names.dart';
+import 'package:linter/src/rules/empty_constructor_bodies.dart';
+import 'package:linter/src/rules/library_names.dart';
+import 'package:linter/src/rules/library_prefixes.dart';
+import 'package:linter/src/rules/non_constant_identifier_names.dart';
+import 'package:linter/src/rules/one_member_abstracts.dart';
+import 'package:linter/src/rules/slash_for_doc_comments.dart';
+import 'package:linter/src/rules/super_goes_last.dart';
+import 'package:linter/src/rules/type_init_formals.dart';
+import 'package:linter/src/rules/unnecessary_brace_in_string_interp.dart';
+import 'package:plugin/plugin.dart';
+
+/// The shared linter plugin instance.
+final LinterPlugin linterPlugin = new LinterPlugin();
+
+/// A plugin that defines the extension points and extensions that are
+/// inherently defined by the linter.
+class LinterPlugin implements Plugin {
+
+  /// A subset of rules that we are considering enabled by "default".
+  static final List<LintRule> _rules = [
+    new CamelCaseTypes(),
+    new ConstantIdentifierNames(),
+    new EmptyConstructorBodies(),
+    new LibraryNames(),
+    new LibraryPrefixes(),
+    new NonConstantIdentifierNames(),
+    new OneMemberAbstracts(),
+    new SlashForDocComments(),
+    new SuperGoesLast(),
+    new TypeInitFormals(),
+    new UnnecessaryBraceInStringInterp()
+  ];
+
+  /// The unique identifier of this plugin.
+  static const String UNIQUE_IDENTIFIER = 'linter.core';
+
+  /// The simple identifier of the extension point that allows plugins to
+  /// register new lint rules.
+  static const String LINT_RULE_EXTENSION_POINT = 'rule';
+
+  /// The extension point that allows plugins to register new lint rules.
+  ExtensionPoint lintRuleExtensionPoint;
+
+  /// Return a list containing all contributed lint rules.
+  List<LintRule> get lintRules => lintRuleExtensionPoint.extensions;
+
+  @override
+  String get uniqueIdentifier => UNIQUE_IDENTIFIER;
+
+  @override
+  void registerExtensionPoints(RegisterExtensionPoint registerExtensionPoint) {
+    lintRuleExtensionPoint = registerExtensionPoint(
+        LINT_RULE_EXTENSION_POINT, _validateTaskExtension);
+  }
+
+  @override
+  void registerExtensions(RegisterExtension registerExtension) {
+    _rules.forEach((LintRule rule) =>
+        registerExtension(LINT_RULE_EXTENSION_POINT_ID, rule));
+  }
+
+  void _validateTaskExtension(Object extension) {
+    if (extension is! LintRule) {
+      String id = lintRuleExtensionPoint.uniqueIdentifier;
+      throw new ExtensionError('Extensions to $id must implement LintRule');
+    }
+  }
+}

pubspec.yaml

@@ -8,6 +8,7 @@ dependencies:
   args: '>=0.12.1 <0.14.0'
   cli_util: '>=0.0.1 <0.1.0'
   glob: '>=1.0.3 <2.0.0'
+  plugin: '<0.2.0'
   source_span: '>=1.0.2 <2.0.0'
   yaml: '>=2.1.2 <3.0.0'
 dev_dependencies:

test/linter_test.dart

@@ -16,13 +16,15 @@ import 'package:linter/src/analysis.dart';
 import 'package:linter/src/ast.dart';
 import 'package:linter/src/io.dart';
 import 'package:linter/src/linter.dart';
+import 'package:linter/src/plugin/linter_plugin.dart';
 import 'package:linter/src/pub.dart';
 import 'package:linter/src/rules.dart';
 import 'package:linter/src/rules/camel_case_types.dart';
 import 'package:linter/src/rules/package_prefixed_library_names.dart';
 import 'package:linter/src/util.dart';
 import 'package:mockito/mockito.dart';
 import 'package:path/path.dart' as p;
+import 'package:plugin/manager.dart';
 import 'package:unittest/unittest.dart';
 
 import '../bin/linter.dart' as dartlint;
@@ -33,6 +35,7 @@ main() {
 
   defineSanityTests();
   defineLinterEngineTests();
+  definePluginTests();
   defineRuleTests();
   defineRuleUnitTests();
 }
@@ -255,6 +258,34 @@ void defineLinterEngineTests() {
   });
 }
 
+/// Default contributed lint rules.
+var builtinRules = [
+  'camel_case_types',
+  'constant_identifier_names',
+  'empty_constructor_bodies',
+  'library_names',
+  'library_prefixes',
+  'non_constant_identifier_names',
+  'one_member_abstracts',
+  'slash_for_doc_comments',
+  'super_goes_last',
+  'type_init_formals',
+  'unnecessary_brace_in_string_interp'
+];
+
+/// Plugin tests
+definePluginTests() {
+  group('plugin', () {
+    test('contributed rules', () {
+      LinterPlugin linterPlugin = new LinterPlugin();
+      ExtensionManager manager = new ExtensionManager();
+      manager.processPlugins([linterPlugin]);
+      var contributedRules = linterPlugin.lintRules.map((rule) => rule.name);
+      expect(contributedRules, unorderedEquals(builtinRules));
+    });
+  });
+}
+
 /// Rule tests
 defineRuleTests() {