fasta tokens implement analyzer token API

pkg/analyzer/lib/src/dart/scanner/scanner.dart

 // Copyright (c) 2014, 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.dart.scanner.scanner;
 
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
 import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:front_end/src/fasta/scanner.dart' as fasta;
+import 'package:front_end/src/fasta/scanner/abstract_scanner.dart'
+    show fastaSupportsGenericMethodComments;
 import 'package:front_end/src/fasta/scanner/precedence.dart' as fasta;
 import 'package:front_end/src/scanner/errors.dart' show translateErrorToken;
 import 'package:front_end/src/scanner/scanner.dart' as fe;
 import 'package:front_end/src/scanner/token.dart' show Token;
 
 export 'package:analyzer/src/dart/error/syntactic_errors.dart';
 export 'package:front_end/src/scanner/scanner.dart' show KeywordState;
 
 /**
  * The class `Scanner` implements a scanner for Dart code.
@@ skipping 11 matching lines @@
    */
   final Source source;
 
   /**
    * The error listener that will be informed of any errors that are found
    * during the scan.
    */
   final AnalysisErrorListener _errorListener;
 
   /**
-   * A flag indicating whether the [Scanner] factory method
-   * will return a fasta based scanner or an analyzer based scanner.
-   */
-  static bool useFasta = false;
-
-  /**
    * Initialize a newly created scanner to scan characters from the given
    * [source]. The given character [reader] will be used to read the characters
    * in the source. The given [_errorListener] will be informed of any errors
    * that are found.
    */
   factory Scanner(Source source, CharacterReader reader,
           AnalysisErrorListener errorListener) =>
-      useFasta
+      fe.Scanner.useFasta
           ? new _Scanner2(source, reader.getContents(), errorListener)
           : new Scanner._(source, reader, errorListener);
 
   Scanner._(this.source, CharacterReader reader, this._errorListener)
       : super.create(reader);
 
   @override
   void reportError(
       ScannerErrorCode errorCode, int offset, List<Object> arguments) {
     _errorListener
@@ skipping 18 matching lines @@
    * during the scan.
    */
   final AnalysisErrorListener _errorListener;
 
   /**
    * The flag specifying whether documentation comments should be parsed.
    */
   bool _preserveComments = true;
 
   @override
-  List<int> lineStarts;
+  final List<int> lineStarts = new List<int>();

[Brian Wilkerson, 2017/03/31 20:39:05]

nit: "<int>[]" is shorter.

[danrubel, 2017/04/04 12:45:41]

Good idea. Done.

 
   @override
   Token firstToken;
 
   @override
   bool scanGenericMethodComments = false;
 
   @override
   bool scanLazyAssignmentOperators = false;
 
-  _Scanner2(this.source, this._contents, this._errorListener);
+  _Scanner2(this.source, this._contents, this._errorListener) {
+    lineStarts.add(0);
+  }
 
   @override
   void appendToken(Token token) {
     throw 'unsupported operation';
   }
 
   @override
   int bigSwitch(int next) {
     throw 'unsupported operation';
   }
@@ skipping 22 matching lines @@
 
   @override
   Token get tail {
     throw 'unsupported operation';
   }
 
   @override
   Token tokenize() {
     // Note: Fasta always supports lazy assignment operators (`&&=` and `||=`),
     // so we can ignore the `scanLazyAssignmentOperators` flag.
-    if (scanGenericMethodComments) {
+    if (scanGenericMethodComments && !fastaSupportsGenericMethodComments) {
       // Fasta doesn't support generic method comments.
       // TODO(danrubel): remove this once fasts support has been added.
       throw 'No generic method comment support in Fasta';
     }
     fasta.ScannerResult result =
         fasta.scanString(_contents, includeComments: _preserveComments);
     // fasta pretends there is an additional line at EOF
-    lineStarts = result.lineStarts.sublist(0, result.lineStarts.length - 1);
+    lineStarts
+        .addAll(result.lineStarts.sublist(1, result.lineStarts.length - 1));
     fasta.Token token = result.tokens;
     // The default recovery strategy used by scanString
     // places all error tokens at the head of the stream.
     while (token.info == fasta.BAD_INPUT_INFO) {
       translateErrorToken(token, reportError);
       token = token.next;
     }
     firstToken = token;
     return firstToken;
   }
 
   @override
   set preserveComments(bool preserveComments) {
     this._preserveComments = preserveComments;
   }
 }