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| 1 // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 library string_scanner.eager_span_scanner; | |
| 6 | |
| 7 import 'package:charcode/ascii.dart'; | |
| 8 | |
| 9 import 'line_scanner.dart'; | |
| 10 import 'span_scanner.dart'; | |
| 11 | |
| 12 // TODO(nweiz): Currently this duplicates code in line_scanner.dart. Once | |
| 13 // sdk#23770 is fully complete, we should move the shared code into a mixin. | |
| 14 | |
| 15 /// A regular expression matching newlines across platforms. | |
| 16 final _newlineRegExp = new RegExp(r"\r\n?|\n"); | |
| 17 | |
| 18 /// A [SpanScanner] that tracks the line and column eagerly, like [LineScanner]. | |
| 19 class EagerSpanScanner extends SpanScanner { | |
| 20 int get line => _line; | |
| 21 int _line = 0; | |
| 22 | |
| 23 int get column => _column; | |
| 24 int _column = 0; | |
| 25 | |
| 26 LineScannerState get state => | |
| 27 new _EagerSpanScannerState(this, position, line, column); | |
| 28 | |
| 29 bool get _betweenCRLF => peekChar(-1) == $cr && peekChar() == $lf; | |
| 30 | |
| 31 set state(LineScannerState state) { | |
| 32 if (state is! _EagerSpanScannerState || | |
| 33 !identical((state as _EagerSpanScannerState)._scanner, this)) { | |
| 34 throw new ArgumentError("The given LineScannerState was not returned by " | |
| 35 "this LineScanner."); | |
| 36 } | |
| 37 | |
| 38 super.position = state.position; | |
| 39 _line = state.line; | |
| 40 _column = state.column; | |
| 41 } | |
| 42 | |
| 43 set position(int newPosition) { | |
| 44 var oldPosition = position; | |
| 45 super.position = newPosition; | |
| 46 | |
| 47 if (newPosition > oldPosition) { | |
| 48 var newlines = _newlinesIn(string.substring(oldPosition, newPosition)); | |
| 49 _line += newlines.length; | |
| 50 if (newlines.isEmpty) { | |
| 51 _column += newPosition - oldPosition; | |
| 52 } else { | |
| 53 _column = newPosition - newlines.last.end; | |
| 54 } | |
| 55 } else { | |
| 56 var newlines = _newlinesIn(string.substring(newPosition, oldPosition)); | |
| 57 if (_betweenCRLF) newlines.removeLast(); | |
| 58 | |
| 59 _line -= newlines.length; | |
| 60 if (newlines.isEmpty) { | |
| 61 _column -= oldPosition - newPosition; | |
| 62 } else { | |
| 63 _column = newPosition - | |
| 64 string.lastIndexOf(_newlineRegExp, newPosition) - 1; | |
| 65 } | |
| 66 } | |
| 67 } | |
| 68 | |
| 69 EagerSpanScanner(String string, {sourceUrl, int position}) | |
| 70 : super(string, sourceUrl: sourceUrl, position: position); | |
| 71 | |
| 72 int readChar() { | |
| 73 var char = super.readChar(); | |
| 74 if (char == $lf || (char == $cr && peekChar() != $lf)) { | |
| 75 _line += 1; | |
| 76 _column = 0; | |
| 77 } else { | |
| 78 _column += 1; | |
| 79 } | |
| 80 return char; | |
| 81 } | |
| 82 | |
| 83 bool scan(Pattern pattern) { | |
| 84 if (!super.scan(pattern)) return false; | |
| 85 | |
| 86 var newlines = _newlinesIn(lastMatch[0]); | |
| 87 _line += newlines.length; | |
| 88 if (newlines.isEmpty) { | |
| 89 _column += lastMatch[0].length; | |
| 90 } else { | |
| 91 _column = lastMatch[0].length - newlines.last.end; | |
| 92 } | |
| 93 | |
| 94 return true; | |
| 95 } | |
| 96 | |
| 97 /// Returns a list of [Match]es describing all the newlines in [text], which | |
| 98 /// is assumed to end at [position]. | |
| 99 List<Match> _newlinesIn(String text) { | |
| 100 var newlines = _newlineRegExp.allMatches(text).toList(); | |
| 101 if (_betweenCRLF) newlines.removeLast(); | |
| 102 return newlines; | |
| 103 } | |
| 104 } | |
| 105 | |
| 106 /// A class representing the state of an [EagerSpanScanner]. | |
| 107 class _EagerSpanScannerState implements LineScannerState { | |
| 108 final EagerSpanScanner _scanner; | |
| 109 final int position; | |
| 110 final int line; | |
| 111 final int column; | |
| 112 | |
| 113 _EagerSpanScannerState(this._scanner, this.position, this.line, this.column); | |
| 114 } | |
| 115 | |
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Chromium Code Reviews
Issue 1400473008:
Roll Observatory packages and add a roll script (Closed)
Base URL: git@github.com:dart-lang/observatory_pub_packages.git@master