LINE_INFO, TOKEN_STREAM access cleanup.

pkg/analyzer/lib/src/task/dart.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.dart;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 2206 matching lines @@
  * A task that merges all of the errors for a single source into a single list
  * of errors.
  */
 class DartErrorsTask extends SourceBasedAnalysisTask {
   /**
    * The task descriptor describing this kind of task.
    */
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor('DartErrorsTask',
       createTask, buildInputs, <ResultDescriptor>[DART_ERRORS]);
 
+  /**
+   * The name of the [LINE_INFO_INPUT] input.
+   */
+  static const String LINE_INFO_INPUT = 'LINE_INFO_INPUT';
+
+  /**
+   * The name of the [PARSED_UNIT_INPUT] input.
+   */
+  static const String PARSED_UNIT_INPUT = 'PARSED_UNIT_INPUT';
+
   // Prefix for comments ignoring error codes.
   static const String _normalizedIgnorePrefix = '//#ignore:';
 
   DartErrorsTask(InternalAnalysisContext context, AnalysisTarget target)
       : super(context, target);
 
   @override
   TaskDescriptor get descriptor => DESCRIPTOR;
 
   @override
@@ skipping 30 matching lines @@
   List<AnalysisError> _filterIgnores(List<AnalysisError> errors) {
     if (errors.isEmpty) {
       return errors;
     }
 
     List<AnalysisError> filtered = <AnalysisError>[];
 
     // Sort errors.
     errors.sort((AnalysisError e1, AnalysisError e2) => e1.offset - e2.offset);
 
-    Source source = target;
-    String contents = context.getContents(source).data;
-    Scanner scanner = new Scanner(source, new CharSequenceReader(contents),
-        AnalysisErrorListener.NULL_LISTENER);
-
-    // Scan.
-    Token token = scanner.tokenize();
-    LineInfo lineInfo = new LineInfo(scanner.lineStarts);
+    CompilationUnit cu = getRequiredInput(PARSED_UNIT_INPUT);
+    Token token = cu.beginToken;
+    LineInfo lineInfo = getRequiredInput(LINE_INFO_INPUT);
 
     int errorIndex = 0;
 
     // Step through tokens looking for comments.
     while (errorIndex < errors.length && token.type != TokenType.EOF) {
       // Find leading comment.
       Token comments = token.precedingComments;
       while (comments?.next != null) {
         comments = comments.next;
       }
@@ skipping 42 matching lines @@
       .contains(error.errorCode.name.toLowerCase());
 
   /**
    * Return a map from the names of the inputs of this kind of task to the task
    * input descriptors describing those inputs for a task with the
    * given [target].
    */
   static Map<String, TaskInput> buildInputs(AnalysisTarget target) {
     Source source = target;
     Map<String, TaskInput> inputs = <String, TaskInput>{};
+    inputs[LINE_INFO_INPUT] = LINE_INFO.of(source);
+    inputs[PARSED_UNIT_INPUT] = PARSED_UNIT.of(source);
     EnginePlugin enginePlugin = AnalysisEngine.instance.enginePlugin;
     // for Source
     for (ResultDescriptor result in enginePlugin.dartErrorsForSource) {
       String inputName = result.name + '_input';
       inputs[inputName] = result.of(source);
     }
     // for LibrarySpecificUnit
     for (ResultDescriptor result in enginePlugin.dartErrorsForUnit) {
       String inputName = result.name + '_input';
       inputs[inputName] =
@@ skipping 3017 matching lines @@
 
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.removeLast();
     return true;
   }
 }