| // 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/visitor.dart'; |
| |
| import '../analyzer.dart'; |
| |
| const _desc = r'DO use curly braces for all flow control structures.'; |
| |
| const _details = r''' |
| |
| **DO** use curly braces for all flow control structures. |
| |
| Doing so avoids the [dangling else](http://en.wikipedia.org/wiki/Dangling_else) |
| problem. |
| |
| **GOOD:** |
| ``` |
| if (isWeekDay) { |
| print('Bike to work!'); |
| } else { |
| print('Go dancing or read a book!'); |
| } |
| ``` |
| |
| There is one exception to this: an `if` statement with no `else` clause where |
| the entire `if` statement and the then body all fit in one line. In that case, |
| you may leave off the braces if you prefer: |
| |
| **GOOD:** |
| ``` |
| if (arg == null) return defaultValue; |
| ``` |
| |
| If the body wraps to the next line, though, use braces: |
| |
| **GOOD:** |
| ``` |
| if (overflowChars != other.overflowChars) { |
| return overflowChars < other.overflowChars; |
| } |
| ``` |
| |
| **BAD:** |
| ```dart |
| if (overflowChars != other.overflowChars) |
| return overflowChars < other.overflowChars; |
| ``` |
| '''; |
| |
| class CurlyBracesInFlowControlStructures extends LintRule |
| implements NodeLintRule { |
| CurlyBracesInFlowControlStructures() |
| : super( |
| name: 'curly_braces_in_flow_control_structures', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| final visitor = _Visitor(this); |
| registry.addDoStatement(this, visitor); |
| registry.addForStatement(this, visitor); |
| registry.addIfStatement(this, visitor); |
| registry.addWhileStatement(this, visitor); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor { |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitDoStatement(DoStatement node) { |
| _check(node.body); |
| } |
| |
| @override |
| void visitForStatement(ForStatement node) { |
| _check(node.body); |
| } |
| |
| @override |
| void visitIfStatement(IfStatement node) { |
| var elseStatement = node.elseStatement; |
| if (elseStatement == null) { |
| if (node.thenStatement is Block) return; |
| |
| final unit = node.root as CompilationUnit; |
| if (unit.lineInfo.getLocation(node.rightParenthesis.end).lineNumber != |
| unit.lineInfo.getLocation(node.thenStatement.end).lineNumber) { |
| rule.reportLint(node.thenStatement); |
| } |
| } else { |
| _check(node.thenStatement); |
| if (elseStatement is! IfStatement) { |
| _check(elseStatement); |
| } |
| } |
| } |
| |
| @override |
| void visitWhileStatement(WhileStatement node) { |
| _check(node.body); |
| } |
| |
| void _check(Statement node) { |
| if (node is! Block) rule.reportLint(node); |
| } |
| } |