| // Copyright (c) 2016, 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 'package:analyzer/dart/constant/value.dart'; |
| |
| import '../analyzer.dart'; |
| |
| const _desc = r"Don't use more than one case with same value."; |
| |
| const _details = r''' |
| |
| **DON'T** use more than one case with same value. |
| |
| This is usually a typo or changed value of constant. |
| |
| **GOOD:** |
| ```dart |
| const int A = 1; |
| switch (v) { |
| case A: |
| case 2: |
| } |
| ``` |
| |
| **BAD:** |
| ```dart |
| const int A = 1; |
| switch (v) { |
| case 1: |
| case 2: |
| case A: |
| case 2: |
| } |
| ``` |
| |
| '''; |
| |
| String message(String value1, String value2) => |
| 'Do not use more than one case with same value ($value1 and $value2)'; |
| |
| class NoDuplicateCaseValues extends LintRule implements NodeLintRule { |
| NoDuplicateCaseValues() |
| : super( |
| name: 'no_duplicate_case_values', |
| description: _desc, |
| details: _details, |
| group: Group.errors); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| var visitor = _Visitor(this, context); |
| registry.addSwitchStatement(this, visitor); |
| } |
| |
| void reportLintWithDescription(AstNode node, String description) { |
| reporter.reportErrorForNode(_LintCode(name, description), node, []); |
| } |
| } |
| |
| class _LintCode extends LintCode { |
| static final registry = <String, _LintCode>{}; |
| |
| factory _LintCode(String name, String message) => |
| registry.putIfAbsent(name + message, () => _LintCode._(name, message)); |
| |
| _LintCode._(String name, String message) : super(name, message); |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final NoDuplicateCaseValues rule; |
| |
| final LinterContext context; |
| |
| _Visitor(this.rule, this.context); |
| |
| @override |
| void visitSwitchStatement(SwitchStatement node) { |
| var values = <DartObject, Expression>{}; |
| |
| for (var member in node.members) { |
| if (member is SwitchCase) { |
| var expression = member.expression; |
| |
| var result = context.evaluateConstant(expression); |
| var value = result.value; |
| |
| if (value == null || !value.hasKnownValue) { |
| continue; |
| } |
| |
| var duplicateValue = values[value]; |
| if (duplicateValue != null) { |
| rule.reportLintWithDescription(member, |
| message(duplicateValue.toString(), expression.toString())); |
| } else { |
| values[value] = expression; |
| } |
| } |
| } |
| } |
| } |