| // Copyright 2019 The Flutter team. 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:string_scanner/string_scanner.dart'; |
| |
| abstract class SyntaxPrehighlighter { |
| List<CodeSpan> format(String src); |
| } |
| |
| class DartSyntaxPrehighlighter extends SyntaxPrehighlighter { |
| DartSyntaxPrehighlighter() { |
| _spans = <_HighlightSpan>[]; |
| } |
| |
| static const List<String> _keywords = <String>[ |
| 'abstract', |
| 'as', |
| 'assert', |
| 'async', |
| 'await', |
| 'break', |
| 'case', |
| 'catch', |
| 'class', |
| 'const', |
| 'continue', |
| 'default', |
| 'deferred', |
| 'do', |
| 'dynamic', |
| 'else', |
| 'enum', |
| 'export', |
| 'external', |
| 'extends', |
| 'factory', |
| 'false', |
| 'final', |
| 'finally', |
| 'for', |
| 'get', |
| 'if', |
| 'implements', |
| 'import', |
| 'in', |
| 'is', |
| 'library', |
| 'new', |
| 'null', |
| 'operator', |
| 'part', |
| 'rethrow', |
| 'return', |
| 'set', |
| 'static', |
| 'super', |
| 'switch', |
| 'sync', |
| 'this', |
| 'throw', |
| 'true', |
| 'try', |
| 'typedef', |
| 'var', |
| 'void', |
| 'while', |
| 'with', |
| 'yield', |
| ]; |
| |
| static const List<String> _builtInTypes = <String>[ |
| 'int', |
| 'double', |
| 'num', |
| 'bool', |
| ]; |
| |
| String _src; |
| StringScanner _scanner; |
| |
| List<_HighlightSpan> _spans; |
| |
| @override |
| List<CodeSpan> format(String src) { |
| _src = src; |
| _scanner = StringScanner(_src); |
| |
| if (_generateSpans()) { |
| // Successfully parsed the code |
| final List<CodeSpan> formattedText = <CodeSpan>[]; |
| int currentPosition = 0; |
| |
| for (_HighlightSpan span in _spans) { |
| if (currentPosition != span.start) { |
| formattedText |
| .add(CodeSpan(text: _src.substring(currentPosition, span.start))); |
| } |
| |
| formattedText |
| .add(CodeSpan(type: span.type, text: span.textForSpan(_src))); |
| |
| currentPosition = span.end; |
| } |
| |
| if (currentPosition != _src.length) { |
| formattedText |
| .add(CodeSpan(text: _src.substring(currentPosition, _src.length))); |
| } |
| |
| return formattedText; |
| } else { |
| // Parsing failed, return with only basic formatting |
| return [CodeSpan(type: _HighlightType.base, text: src)]; |
| } |
| } |
| |
| bool _generateSpans() { |
| int lastLoopPosition = _scanner.position; |
| |
| while (!_scanner.isDone) { |
| // Skip White space |
| _scanner.scan(RegExp(r'\s+')); |
| |
| // Block comments |
| if (_scanner.scan(RegExp(r'/\*(.|\n)*\*/'))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.comment, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Line comments |
| if (_scanner.scan('//')) { |
| final int startComment = _scanner.lastMatch.start; |
| |
| bool eof = false; |
| int endComment; |
| if (_scanner.scan(RegExp(r'.*\n'))) { |
| endComment = _scanner.lastMatch.end - 1; |
| } else { |
| eof = true; |
| endComment = _src.length; |
| } |
| |
| _spans.add(_HighlightSpan( |
| _HighlightType.comment, |
| startComment, |
| endComment, |
| )); |
| |
| if (eof) { |
| break; |
| } |
| |
| continue; |
| } |
| |
| // Raw r"String" |
| if (_scanner.scan(RegExp(r'r".*"'))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.string, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Raw r'String' |
| if (_scanner.scan(RegExp(r"r'.*'"))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.string, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Multiline """String""" |
| if (_scanner.scan(RegExp(r'"""(?:[^"\\]|\\(.|\n))*"""'))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.string, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Multiline '''String''' |
| if (_scanner.scan(RegExp(r"'''(?:[^'\\]|\\(.|\n))*'''"))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.string, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // "String" |
| if (_scanner.scan(RegExp(r'"(?:[^"\\]|\\.)*"'))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.string, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // 'String' |
| if (_scanner.scan(RegExp(r"'(?:[^'\\]|\\.)*'"))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.string, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Double |
| if (_scanner.scan(RegExp(r'\d+\.\d+'))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.number, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Integer |
| if (_scanner.scan(RegExp(r'\d+'))) { |
| _spans.add(_HighlightSpan(_HighlightType.number, |
| _scanner.lastMatch.start, _scanner.lastMatch.end)); |
| continue; |
| } |
| |
| // Punctuation |
| if (_scanner.scan(RegExp(r'[\[\]{}().!=<>&\|\?\+\-\*/%\^~;:,]'))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.punctuation, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Meta data |
| if (_scanner.scan(RegExp(r'@\w+'))) { |
| _spans.add(_HighlightSpan( |
| _HighlightType.keyword, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| continue; |
| } |
| |
| // Words |
| if (_scanner.scan(RegExp(r'\w+'))) { |
| _HighlightType type; |
| |
| String word = _scanner.lastMatch[0]; |
| if (word.startsWith('_')) { |
| word = word.substring(1); |
| } |
| |
| if (_keywords.contains(word)) { |
| type = _HighlightType.keyword; |
| } else if (_builtInTypes.contains(word)) { |
| type = _HighlightType.keyword; |
| } else if (_firstLetterIsUpperCase(word)) { |
| type = _HighlightType.klass; |
| } else if (word.length >= 2 && |
| word.startsWith('k') && |
| _firstLetterIsUpperCase(word.substring(1))) { |
| type = _HighlightType.constant; |
| } |
| |
| if (type != null) { |
| _spans.add(_HighlightSpan( |
| type, |
| _scanner.lastMatch.start, |
| _scanner.lastMatch.end, |
| )); |
| } |
| } |
| |
| // Check if this loop did anything |
| if (lastLoopPosition == _scanner.position) { |
| // Failed to parse this file, abort gracefully |
| return false; |
| } |
| lastLoopPosition = _scanner.position; |
| } |
| |
| _simplify(); |
| return true; |
| } |
| |
| void _simplify() { |
| for (int i = _spans.length - 2; i >= 0; i -= 1) { |
| if (_spans[i].type == _spans[i + 1].type && |
| _spans[i].end == _spans[i + 1].start) { |
| _spans[i] = _HighlightSpan( |
| _spans[i].type, |
| _spans[i].start, |
| _spans[i + 1].end, |
| ); |
| _spans.removeAt(i + 1); |
| } |
| } |
| } |
| |
| bool _firstLetterIsUpperCase(String str) { |
| if (str.isNotEmpty) { |
| final String first = str.substring(0, 1); |
| return first == first.toUpperCase(); |
| } |
| return false; |
| } |
| } |
| |
| enum _HighlightType { |
| number, |
| comment, |
| keyword, |
| string, |
| punctuation, |
| klass, |
| constant, |
| base, |
| } |
| |
| class _HighlightSpan { |
| _HighlightSpan(this.type, this.start, this.end); |
| final _HighlightType type; |
| final int start; |
| final int end; |
| |
| String textForSpan(String src) { |
| return src.substring(start, end); |
| } |
| } |
| |
| class CodeSpan { |
| CodeSpan({this.type = _HighlightType.base, this.text}); |
| |
| final _HighlightType type; |
| final String text; |
| |
| @override |
| String toString() { |
| return 'TextSpan(' |
| 'style: codeStyle.${_styleNameOf(type)}, ' |
| "text: '${_escape(text)}'" |
| ')'; |
| } |
| } |
| |
| String _styleNameOf(_HighlightType type) { |
| switch (type) { |
| case _HighlightType.number: |
| return 'numberStyle'; |
| case _HighlightType.comment: |
| return 'commentStyle'; |
| case _HighlightType.keyword: |
| return 'keywordStyle'; |
| case _HighlightType.string: |
| return 'stringStyle'; |
| case _HighlightType.punctuation: |
| return 'punctuationStyle'; |
| case _HighlightType.klass: |
| return 'classStyle'; |
| case _HighlightType.constant: |
| return 'constantStyle'; |
| case _HighlightType.base: |
| return 'baseStyle'; |
| } |
| return ''; |
| } |
| |
| String _escape(String text) { |
| StringBuffer escapedText = StringBuffer(); |
| |
| for (final char in text.runes) { |
| if (char < 0x20 || |
| char >= 0x7F || |
| char == 0x22 || |
| char == 0x24 || |
| char == 0x27 || |
| char == 0x5C) { |
| if (char <= 0xffff) { |
| escapedText.write("\\u${_encodeAndPad(char)}"); |
| } else { |
| escapedText.write("\\u{${_encode(char)}}"); |
| } |
| } else { |
| escapedText.write(String.fromCharCode(char)); |
| } |
| } |
| |
| return escapedText.toString(); |
| } |
| |
| String _encode(int charCode) { |
| return charCode.toRadixString(16); |
| } |
| |
| String _encodeAndPad(int charCode) { |
| String encoded = _encode(charCode); |
| return '0' * (4 - encoded.length) + encoded; |
| } |
