| // Copyright (c) 2015, 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. |
| |
| import 'package:charcode/ascii.dart'; |
| |
| import 'line_scanner.dart'; |
| import 'span_scanner.dart'; |
| |
| // TODO(nweiz): Currently this duplicates code in line_scanner.dart. Once |
| // sdk#23770 is fully complete, we should move the shared code into a mixin. |
| |
| /// A regular expression matching newlines across platforms. |
| final _newlineRegExp = new RegExp(r"\r\n?|\n"); |
| |
| /// A [SpanScanner] that tracks the line and column eagerly, like [LineScanner]. |
| class EagerSpanScanner extends SpanScanner { |
| int get line => _line; |
| int _line = 0; |
| |
| int get column => _column; |
| int _column = 0; |
| |
| LineScannerState get state => |
| new _EagerSpanScannerState(this, position, line, column); |
| |
| bool get _betweenCRLF => peekChar(-1) == $cr && peekChar() == $lf; |
| |
| set state(LineScannerState state) { |
| if (state is! _EagerSpanScannerState || |
| !identical((state as _EagerSpanScannerState)._scanner, this)) { |
| throw new ArgumentError("The given LineScannerState was not returned by " |
| "this LineScanner."); |
| } |
| |
| super.position = state.position; |
| _line = state.line; |
| _column = state.column; |
| } |
| |
| set position(int newPosition) { |
| var oldPosition = position; |
| super.position = newPosition; |
| |
| if (newPosition > oldPosition) { |
| var newlines = _newlinesIn(string.substring(oldPosition, newPosition)); |
| _line += newlines.length; |
| if (newlines.isEmpty) { |
| _column += newPosition - oldPosition; |
| } else { |
| _column = newPosition - newlines.last.end; |
| } |
| } else { |
| var newlines = _newlinesIn(string.substring(newPosition, oldPosition)); |
| if (_betweenCRLF) newlines.removeLast(); |
| |
| _line -= newlines.length; |
| if (newlines.isEmpty) { |
| _column -= oldPosition - newPosition; |
| } else { |
| _column = newPosition - |
| string.lastIndexOf(_newlineRegExp, newPosition) - 1; |
| } |
| } |
| } |
| |
| EagerSpanScanner(String string, {sourceUrl, int position}) |
| : super(string, sourceUrl: sourceUrl, position: position); |
| |
| int readChar() { |
| var char = super.readChar(); |
| if (char == $lf || (char == $cr && peekChar() != $lf)) { |
| _line += 1; |
| _column = 0; |
| } else { |
| _column += 1; |
| } |
| return char; |
| } |
| |
| bool scan(Pattern pattern) { |
| if (!super.scan(pattern)) return false; |
| |
| var newlines = _newlinesIn(lastMatch[0]); |
| _line += newlines.length; |
| if (newlines.isEmpty) { |
| _column += lastMatch[0].length; |
| } else { |
| _column = lastMatch[0].length - newlines.last.end; |
| } |
| |
| return true; |
| } |
| |
| /// Returns a list of [Match]es describing all the newlines in [text], which |
| /// is assumed to end at [position]. |
| List<Match> _newlinesIn(String text) { |
| var newlines = _newlineRegExp.allMatches(text).toList(); |
| if (_betweenCRLF) newlines.removeLast(); |
| return newlines; |
| } |
| } |
| |
| /// A class representing the state of an [EagerSpanScanner]. |
| class _EagerSpanScannerState implements LineScannerState { |
| final EagerSpanScanner _scanner; |
| final int position; |
| final int line; |
| final int column; |
| |
| _EagerSpanScannerState(this._scanner, this.position, this.line, this.column); |
| } |
| |