fasta tokens implement analyzer token API

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

Index: pkg/analyzer/lib/src/dart/scanner/scanner.dart
diff --git a/pkg/analyzer/lib/src/dart/scanner/scanner.dart b/pkg/analyzer/lib/src/dart/scanner/scanner.dart
index 821768723e95b5591c59c404527129a734404a7f..0e92e3086bff85627886b8a921170adaa865428b 100644
--- a/pkg/analyzer/lib/src/dart/scanner/scanner.dart
+++ b/pkg/analyzer/lib/src/dart/scanner/scanner.dart
@@ -10,6 +10,8 @@ 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;
@@ -41,12 +43,6 @@ class Scanner extends fe.Scanner {
   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
@@ -54,7 +50,7 @@ class Scanner extends fe.Scanner {
    */
   factory Scanner(Source source, CharacterReader reader,
           AnalysisErrorListener errorListener) =>
-      useFasta
+      fe.Scanner.useFasta
           ? new _Scanner2(source, reader.getContents(), errorListener)
           : new Scanner._(source, reader, errorListener);
 
@@ -93,7 +89,7 @@ class _Scanner2 implements Scanner {
   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;
@@ -104,7 +100,9 @@ class _Scanner2 implements Scanner {
   @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) {
@@ -147,7 +145,7 @@ class _Scanner2 implements Scanner {
   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';
@@ -155,7 +153,8 @@ class _Scanner2 implements Scanner {
     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.