Analysis Options processing task and manager.

pkg/analyzer/lib/source/analysis_options_provider.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 source.analysis_options_provider;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
+import 'package:source_span/source_span.dart';
 import 'package:yaml/yaml.dart';
 
 /// Provide the options found in the `.analysis_options` file.
 class AnalysisOptionsProvider {
   /// Provide the options found in [root]/[ANALYSIS_OPTIONS_FILE].
   /// Return an empty options map if the file does not exist.
   Map<String, YamlNode> getOptions(Folder root) {
     var optionsSource = _readAnalysisOptionsFile(
         root.getChild(AnalysisEngine.ANALYSIS_OPTIONS_FILE));
     return getOptionsFromString(optionsSource);
   }
 
   /// Provide the options found in [file].
   /// Return an empty options map if the file does not exist.
   Map<String, YamlNode> getOptionsFromFile(File file) {
     var optionsSource = _readAnalysisOptionsFile(file);
     return getOptionsFromString(optionsSource);
   }
 
   /// Provide the options found in [optionsSource].
   /// Return an empty options map if the source is null.
   Map<String, YamlNode> getOptionsFromString(String optionsSource) {
     var options = <String, YamlNode>{};
     if (optionsSource == null) {
       return options;
     }
     var doc = loadYaml(optionsSource);
     if ((doc != null) && (doc is! YamlMap)) {
-      throw new Exception(
+      throw new OptionsFormatException(
           'Bad options file format (expected map, got ${doc.runtimeType})\n'
           'contents of options file:\n'
-          '$optionsSource\n');
+          '$optionsSource\n',
+          doc.span);
     }
     if (doc is YamlMap) {
       doc.forEach((k, v) {
         if (k is! String) {
-          throw new Exception(
+          throw new OptionsFormatException(
               'Bad options file format (expected String scope key, '
-              'got ${k.runtimeType})');
+              'got ${k.runtimeType})',
+              k != null ? k.span : doc.span);
         }
         options[k] = v;
       });
     }
     return options;
   }
 
   /// Read the contents of [file] as a string.
   /// Returns null if file does not exist.
   String _readAnalysisOptionsFile(File file) {
     try {
       return file.readAsStringSync();
     } on FileSystemException {
       // File can't be read.
       return null;
     }
   }
 }
+
+/// Thrown on options format exceptions.
+class OptionsFormatException implements Exception {
+  final String message;
+  final SourceSpan span;
+  OptionsFormatException(this.message, [this.span]);
+
+  @override
+  String toString() =>
+      'OptionsFormatException: ${message?.toString()}, ${span?.toString()}';
+}