Scan generic method comments with Fasta.

pkg/front_end/lib/src/fasta/scanner/abstract_scanner.dart

 // Copyright (c) 2012, 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 fasta.scanner.abstract_scanner;
 
 import 'dart:collection' show ListMixin;
 
 import 'dart:typed_data' show Uint16List, Uint32List;
 
 import '../scanner.dart'
     show ErrorToken, Scanner, buildUnexpectedCharacterToken;
 
 import 'error_token.dart' show UnterminatedToken;
 
 import 'keyword.dart' show KeywordState, Keyword;
 
 import 'precedence.dart';
 
-import 'token.dart' show BeginGroupToken, CommentToken, SymbolToken, Token;
+import 'token.dart'
+    show BeginGroupToken, CommentToken, DartDocToken, SymbolToken, Token;
 
 import 'token_constants.dart';
 
 import 'characters.dart';
 
 abstract class AbstractScanner implements Scanner {
   final bool includeComments;
 
   /**
+   * A flag indicating whether to parse generic method comments, of the form
+   * `/*=T*/` and `/*<T>*/`.  The flag [includeComments] must be set to `true`.
+   */
+  bool scanGenericMethodComments = false;
+
+  /**
    * The string offset for the next token that will be created.
    *
    * Note that in the [Utf8BytesScanner], [stringOffset] and [scanOffset] values
    * are different. One string character can be encoded using multiple UTF-8
    * bytes.
    */
   int tokenStart = -1;
 
   /**
    * A pointer to the token stream created by this scanner. The first token
@@ skipping 138 matching lines @@
 
   /** Documentation in subclass [ArrayBasedScanner]. */
   int appendEndGroup(PrecedenceInfo info, int openKind);
 
   /** Documentation in subclass [ArrayBasedScanner]. */
   void appendGt(PrecedenceInfo info);
 
   /** Documentation in subclass [ArrayBasedScanner]. */
   void appendGtGt(PrecedenceInfo info);
 
-  /** Documentation in subclass [ArrayBasedScanner]. */
-  void appendComment(start, PrecedenceInfo info, bool asciiOnly);
-
-  /** Documentation in subclass [ArrayBasedScanner]. */
-  void appendDartDoc(start, PrecedenceInfo info, bool asciiOnly);
-
   /// Append [token] to the token stream.
   void appendErrorToken(ErrorToken token);
 
+  /**
+   * Returns a new comment from the scan offset [start] to the current
+   * [scanOffset] plus the [extraOffset]. For example, if the current
+   * scanOffset is 10, then [appendSubstringToken(5, -1)] will append the
+   * substring string [5,9).
+   *
+   * Note that [extraOffset] can only be used if the covered character(s) are
+   * known to be ASCII.
+   */
+  CommentToken createCommentToken(
+      PrecedenceInfo info, int start, bool asciiOnly,
+      [int extraOffset = 0]);
+
+  /**
+   * Returns a new dartdoc from the scan offset [start] to the current
+   * [scanOffset] plus the [extraOffset]. For example, if the current
+   * scanOffset is 10, then [appendSubstringToken(5, -1)] will append the
+   * substring string [5,9).
+   *
+   * Note that [extraOffset] can only be used if the covered character(s) are
+   * known to be ASCII.
+   */
+  DartDocToken createDartDocToken(
+      PrecedenceInfo info, int start, bool asciiOnly,
+      [int extraOffset = 0]);
+
   /** Documentation in subclass [ArrayBasedScanner]. */
   void discardOpenLt();
 
   /// Return true when at EOF.
   bool atEndOfFile();
 
   Token tokenize() {
     while (!atEndOfFile()) {
       int next = advance();
       while (!identical(next, $EOF)) {
@@ skipping 584 matching lines @@
         if (next > 127) {
           asciiOnlyLines = false;
           asciiOnlyComment = false;
         }
         next = advance();
       }
     }
     return next;
   }
 
+  void appendComment(int start, PrecedenceInfo info, bool asciiOnly) {
+    if (!includeComments) return;
+    CommentToken newComment = createCommentToken(info, start, asciiOnly);
+    if (scanGenericMethodComments) {
+      String value = newComment.lexeme;
+      int length = value.length;
+      if (length > 5 &&
+          value.codeUnitAt(0) == $SLASH &&
+          value.codeUnitAt(1) == $STAR &&
+          value.codeUnitAt(2) == $EQ) {
+        newComment = new CommentToken.fromString(
+            GENERIC_METHOD_TYPE_ASSIGN, value, start);
+      } else if (length > 6 &&
+          value.codeUnitAt(0) == $SLASH &&
+          value.codeUnitAt(1) == $STAR &&
+          value.codeUnitAt(2) == $LT &&
+          value.codeUnitAt(length - 1) == $SLASH &&
+          value.codeUnitAt(length - 2) == $STAR &&
+          value.codeUnitAt(length - 3) == $GT) {
+        newComment =
+            new CommentToken.fromString(GENERIC_METHOD_TYPE_LIST, value, start);
+      }
+    }
+    _appendToCommentStream(newComment);
+  }
+
+  void appendDartDoc(int start, PrecedenceInfo info, bool asciiOnly) {
+    if (!includeComments) return;
+    Token newComment = createDartDocToken(info, start, asciiOnly);
+    _appendToCommentStream(newComment);
+  }
+
+  /**
+   * Append the given token to the [tail] of the current stream of tokens.
+   */
+  void appendToken(Token token) {
+    tail.next = token;
+    tail.next.previousToken = tail;
+    tail = tail.next;
+    if (comments != null) {
+      tail.precedingCommentTokens = comments;
+      comments = null;
+      commentsTail = null;
+    }
+  }
+
+  void _appendToCommentStream(Token newComment) {
+    if (comments == null) {
+      comments = newComment;
+      commentsTail = comments;
+    } else {
+      commentsTail.next = newComment;
+      commentsTail.next.previousToken = commentsTail;
+      commentsTail = commentsTail.next;
+    }
+  }
+
   int tokenizeRawStringKeywordOrIdentifier(int next) {
     // [next] is $r.
     int nextnext = peek();
     if (identical(nextnext, $DQ) || identical(nextnext, $SQ)) {
       int start = scanOffset;
       next = advance();
       return tokenizeString(next, start, true);
     }
     return tokenizeKeywordOrIdentifier(next, true);
   }
@@ skipping 386 matching lines @@
       switchToUint32(newLength);
     }
   }
 
   void switchToUint32(int newLength) {
     final newArray = new Uint32List(newLength);
     newArray.setRange(0, arrayLength, array);
     array = newArray;
   }
 }