OptionsValidator plugin extension and linter service.

pkg/analyzer/lib/src/task/options.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.src.task.options;
 
 import 'package:analyzer/analyzer.dart';
+import 'package:analyzer/plugin/options.dart';
 import 'package:analyzer/source/analysis_options_provider.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/general.dart';
 import 'package:analyzer/task/general.dart';
 import 'package:analyzer/task/model.dart';
 import 'package:source_span/source_span.dart';
 import 'package:yaml/yaml.dart';
 
 /// The errors produced while parsing `.analysis_options` files.
 ///
 /// The list will be empty if there were no errors, but will not be `null`.
 final ListResultDescriptor<AnalysisError> ANALYSIS_OPTIONS_ERRORS =
     new ListResultDescriptor<AnalysisError>(
         'ANALYSIS_OPTIONS_ERRORS', AnalysisError.NO_ERRORS);
 
 /// Validates `analyzer` top-level options.
 class AnalyzerOptionsValidator extends TopLevelOptionValidator {
   AnalyzerOptionsValidator()
       : super('analyzer', const ['exclude', 'plugins', 'strong-mode']);
 }
 
+/// Convenience class for composing validators.
+class CompositeValidator extends OptionsValidator {
+  final List<OptionsValidator> validators;
+  CompositeValidator(this.validators);
+
+  @override
+  void validate(ErrorReporter reporter, Map<String, YamlNode> options) =>
+      validators.forEach((v) => v.validate(reporter, options));
+}
+
 /// A task that generates errors for an `.analysis_options` file.
 class GenerateOptionsErrorsTask extends SourceBasedAnalysisTask {
   /// The name of the input whose value is the content of the file.
   static const String CONTENT_INPUT_NAME = 'CONTENT_INPUT_NAME';
 
   /// The task descriptor describing this kind of task.
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
       'GenerateOptionsErrorsTask',
       createTask,
       buildInputs,
@@ skipping 49 matching lines @@
 
 /// Validates `linter` top-level options.
 /// TODO(pq): move into `linter` package and plugin.
 class LinterOptionsValidator extends TopLevelOptionValidator {
   LinterOptionsValidator() : super('linter', const ['rules']);
 }
 
 /// Validates options defined in an `.analysis_options` file.
 class OptionsFileValidator {
   // TODO(pq): move to an extension point.
-  static final List<OptionsValidator> _validators = [
-    new AnalyzerOptionsValidator(), new LinterOptionsValidator()
+  final List<OptionsValidator> _validators = [
+    new AnalyzerOptionsValidator(),
+    new LinterOptionsValidator()
   ];
 
   final Source source;
-  OptionsFileValidator(this.source);
+  OptionsFileValidator(this.source) {
+    _validators.addAll(AnalysisEngine.instance.optionsPlugin.optionsValidators);
+  }
 
   List<AnalysisError> validate(Map<String, YamlNode> options) {
     RecordingErrorListener recorder = new RecordingErrorListener();
     ErrorReporter reporter = new ErrorReporter(recorder, source);
     _validators.forEach((OptionsValidator v) => v.validate(reporter, options));
     return recorder.errors;
   }
 }
 
-/// Validates options.
-abstract class OptionsValidator {
-  /// Validate [options], reporting any errors to the given [reporter].
-  void validate(ErrorReporter reporter, Map<String, YamlNode> options);
-}
-
 /// Validates top-level options. For example,
 ///     plugin:
 ///       top-level-option: true
 class TopLevelOptionValidator extends OptionsValidator {
   final String pluginName;
   final List<String> supportedOptions;
 
   TopLevelOptionValidator(this.pluginName, this.supportedOptions);
   @override
   void validate(ErrorReporter reporter, Map<String, YamlNode> options) {
     YamlNode node = options[pluginName];
     if (node is YamlMap) {
       node.nodes.forEach((k, v) {
         if (k is YamlScalar) {
           if (!supportedOptions.contains(k.value)) {
             reporter.reportErrorForSpan(
                 AnalysisOptionsWarningCode.UNSUPPORTED_OPTION,
                 k.span,
                 [pluginName, k.value]);
           }
         }
         //TODO(pq): consider an error if the node is not a Scalar.
       });
     }
   }
 }