blob: 4d5da679259f0d1c7495f5bfd56dac8d2dd7f798 [file] [log] [blame]
// 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 dart2js.tokens.token_map;
import 'package:front_end/src/fasta/scanner.dart' show Token;
* Key class used in [TokenMap] in which the hash code for a token is based
* on the [charOffset].
class TokenKey {
final Token token;
int get hashCode => token.charOffset;
operator ==(other) => other is TokenKey && token == other.token;
/// Map of tokens and the first associated comment.
* This implementation was chosen among several candidates for its space/time
* efficiency by empirical tests of running dartdoc on dartdoc itself. Time
* measurements for the use of [Compiler.commentMap]:
* 1) Using [TokenKey] as key (this class): ~80 msec
* 2) Using [TokenKey] as key + storing a separate map in each script: ~120 msec
* 3) Using [Token] as key in a [Map]: ~38000 msec
* 4) Storing comments is new field in [Token]: ~20 msec
* (Abandoned due to the increased memory usage)
* 5) Storing comments in an [Expando]: ~14000 msec
* 6) Storing token/comments pairs in a linked list: ~5400 msec
class TokenMap {
Map<TokenKey, Token> comments = new Map<TokenKey, Token>();
Token operator [](Token key) {
if (key == null) return null;
return comments[new TokenKey(key)];
void operator []=(Token key, Token value) {
if (key == null) return;
comments[new TokenKey(key)] = value;