| // Copyright (c) 2018, 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:analyzer/dart/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/token.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| |
| import '../analyzer.dart'; |
| |
| const _cr = '\r'; |
| |
| const _desc = r'AVOID lines longer than 80 characters.'; |
| |
| const _details = r''' |
| |
| **AVOID** lines longer than 80 characters |
| |
| Readability studies show that long lines of text are harder to read because your |
| eye has to travel farther when moving to the beginning of the next line. This is |
| why newspapers and magazines use multiple columns of text. |
| |
| If you really find yourself wanting lines longer than 80 characters, our |
| experience is that your code is likely too verbose and could be a little more |
| compact. The main offender is usually `VeryLongCamelCaseClassNames`. Ask |
| yourself, “Does each word in that type name tell me something critical or |
| prevent a name collision?” If not, consider omitting it. |
| |
| Note that dartfmt does 99% of this for you, but the last 1% is you. It does not |
| split long string literals to fit in 80 columns, so you have to do that |
| manually. |
| |
| We make an exception for URIs and file paths. When those occur in comments or |
| strings (usually in imports and exports), they may remain on a single line even |
| if they go over the line limit. This makes it easier to search source files for |
| a given path. |
| '''; |
| |
| const _lf = '\n'; |
| |
| /// String looks like URI if it contains a slash or backslash. |
| final _uriRegExp = RegExp(r'[/\\]'); |
| bool _looksLikeUriOrPath(String value) => _uriRegExp.hasMatch(value); |
| |
| class LinesLongerThan80Chars extends LintRule implements NodeLintRule { |
| LinesLongerThan80Chars() |
| : super( |
| name: 'lines_longer_than_80_chars', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| final visitor = _Visitor(this, context); |
| registry.addCompilationUnit(this, visitor); |
| } |
| } |
| |
| class _AllowedCommentVisitor extends SimpleAstVisitor { |
| final LineInfo lineInfo; |
| |
| final allowedLines = <int>[]; |
| _AllowedCommentVisitor(this.lineInfo); |
| |
| @override |
| void visitCompilationUnit(CompilationUnit node) { |
| var token = node.beginToken; |
| while (token != null) { |
| _getPrecedingComments(token).forEach(_visitComment); |
| if (token == token.next) break; |
| token = token.next; |
| } |
| } |
| |
| Iterable<Token> _getPrecedingComments(Token token) sync* { |
| Token comment = token.precedingComments; |
| while (comment != null) { |
| yield comment; |
| comment = comment.next; |
| } |
| } |
| |
| void _visitComment(Token comment) { |
| final content = comment.lexeme; |
| final lines = <String>[]; |
| if (content.startsWith('///')) { |
| lines.add(content.substring(3)); |
| } else if (content.startsWith('//')) { |
| final commentContent = content.substring(2); |
| if (commentContent.trimLeft().startsWith('ignore:')) { |
| allowedLines.add(lineInfo.getLocation(comment.offset).lineNumber); |
| } else { |
| lines.add(commentContent); |
| } |
| } else if (content.startsWith('/*')) { |
| // remove last slash before finding slash |
| lines.addAll(content |
| .substring(2, content.length - 2) |
| .split('$_cr$_lf') |
| .expand((e) => e.split(_cr)) |
| .expand((e) => e.split(_lf))); |
| } |
| for (var i = 0; i < lines.length; i++) { |
| final value = lines[i]; |
| if (_looksLikeUriOrPath(value)) { |
| final line = lineInfo.getLocation(comment.offset).lineNumber + i; |
| allowedLines.add(line); |
| } |
| } |
| } |
| } |
| |
| class _AllowedLongLineVisitor extends RecursiveAstVisitor { |
| final LineInfo lineInfo; |
| |
| final allowedLines = <int>[]; |
| _AllowedLongLineVisitor(this.lineInfo); |
| |
| @override |
| void visitSimpleStringLiteral(SimpleStringLiteral node) { |
| if (node.isMultiline) { |
| _handleMultilines(node); |
| } else { |
| _handleSingleLine(node, node.value); |
| } |
| } |
| |
| @override |
| void visitStringInterpolation(StringInterpolation node) { |
| if (node.isMultiline) { |
| _handleMultilines(node); |
| } else { |
| final value = node.elements.map((e) { |
| if (e is InterpolationString) return e.value; |
| if (e is InterpolationExpression) return ' ' * e.length; |
| throw ArgumentError( |
| 'Unhandled string interpolation element: ${node.runtimeType}'); |
| }).join(); |
| _handleSingleLine(node, value); |
| } |
| } |
| |
| void _handleMultilines(SingleStringLiteral node) { |
| final startLine = lineInfo.getLocation(node.offset).lineNumber; |
| final endLine = lineInfo.getLocation(node.end).lineNumber; |
| for (var i = startLine; i <= endLine; i++) { |
| allowedLines.add(i); |
| } |
| } |
| |
| void _handleSingleLine(AstNode node, String value) { |
| if (_looksLikeUriOrPath(value)) { |
| final line = lineInfo.getLocation(node.offset).lineNumber; |
| allowedLines.add(line); |
| } |
| } |
| } |
| |
| class _LineInfo { |
| final int index; |
| final int offset; |
| final int end; |
| _LineInfo({this.index, this.offset, this.end}); |
| int get length => end - offset; |
| } |
| |
| class _Visitor extends SimpleAstVisitor { |
| final LintRule rule; |
| |
| final LinterContext context; |
| |
| _Visitor(this.rule, this.context); |
| |
| @override |
| void visitCompilationUnit(CompilationUnit node) { |
| final lineInfo = node.lineInfo; |
| final lineCount = lineInfo.lineCount; |
| final longLines = <_LineInfo>[]; |
| for (var i = 0; i < lineCount; i++) { |
| final start = lineInfo.getOffsetOfLine(i); |
| int end; |
| if (i == lineCount - 1) { |
| end = node.end; |
| } else { |
| end = lineInfo.getOffsetOfLine(i + 1) - 1; |
| final length = end - start; |
| if (length > 80) { |
| if (context.currentUnit.content[end] == _lf && |
| context.currentUnit.content[end - 1] == _cr) { |
| end--; |
| } |
| } |
| } |
| final length = end - start; |
| if (length > 80) { |
| final line = _LineInfo(index: i, offset: start, end: end); |
| longLines.add(line); |
| } |
| } |
| |
| if (longLines.isEmpty) return; |
| |
| final allowedLineVisitor = _AllowedLongLineVisitor(lineInfo); |
| node.accept(allowedLineVisitor); |
| final allowedCommentVisitor = _AllowedCommentVisitor(lineInfo); |
| node.accept(allowedCommentVisitor); |
| |
| final allowedLines = [ |
| ...allowedLineVisitor.allowedLines, |
| ...allowedCommentVisitor.allowedLines |
| ]; |
| |
| for (final line in longLines) { |
| if (allowedLines.contains(line.index + 1)) continue; |
| rule.reporter |
| .reportErrorForOffset(rule.lintCode, line.offset, line.length); |
| } |
| } |
| } |