| // Copyright (c) 2017, 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'Separate the control structure expression from its statement.'; |
| |
| const _details = r''' |
| |
| From the [flutter style guide](https://flutter.dev/style-guide/): |
| |
| **DO** separate the control structure expression from its statement. |
| |
| Don't put the statement part of an `if`, `for`, `while`, `do` on the same line |
| as the expression, even if it is short. Doing so makes it unclear that there |
| is relevant code there. This is especially important for early returns. |
| |
| **GOOD:** |
| ``` |
| if (notReady) |
| return; |
| |
| if (notReady) |
| return; |
| else |
| print('ok') |
| |
| while (condition) |
| i += 1; |
| ``` |
| |
| **BAD:** |
| ``` |
| if (notReady) return; |
| |
| if (notReady) |
| return; |
| else print('ok') |
| |
| while (condition) i += 1; |
| ``` |
| |
| '''; |
| |
| class AlwaysPutControlBodyOnNewLine extends LintRule implements NodeLintRule { |
| AlwaysPutControlBodyOnNewLine() |
| : super( |
| name: 'always_put_control_body_on_new_line', |
| 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<void> { |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitDoStatement(DoStatement node) { |
| _checkNodeOnNextLine(node.body, node.doKeyword.end); |
| } |
| |
| @override |
| void visitForStatement(ForStatement node) { |
| _checkNodeOnNextLine(node.body, node.rightParenthesis.end); |
| } |
| |
| @override |
| void visitIfStatement(IfStatement node) { |
| _checkNodeOnNextLine(node.thenStatement, node.rightParenthesis.end); |
| if (node.elseKeyword != null && node.elseStatement is! IfStatement) { |
| _checkNodeOnNextLine(node.elseStatement, node.elseKeyword.end); |
| } |
| } |
| |
| @override |
| void visitWhileStatement(WhileStatement node) { |
| _checkNodeOnNextLine(node.body, node.rightParenthesis.end); |
| } |
| |
| void _checkNodeOnNextLine(AstNode node, int controlEnd) { |
| if (node is Block && node.statements.isEmpty) return; |
| |
| final unit = node.root as CompilationUnit; |
| final offsetFirstStatement = |
| node is Block ? node.statements.first.offset : node.offset; |
| if (unit.lineInfo.getLocation(controlEnd).lineNumber == |
| unit.lineInfo.getLocation(offsetFirstStatement).lineNumber) { |
| rule.reportLintForToken(node.beginToken); |
| } |
| } |
| } |