| // 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 'dart:collection'; |
| |
| import 'package:analyzer/dart/analysis/declared_variables.dart'; |
| import 'package:analyzer/dart/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| import 'package:analyzer/error/listener.dart'; |
| import 'package:linter/src/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:** |
| ``` |
| const int A = 1; |
| switch (v) { |
| case A: |
| case 2: |
| } |
| ``` |
| |
| **BAD:** |
| ``` |
| 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]) { |
| final visitor = new _Visitor(this, context); |
| registry.addSwitchStatement(this, visitor); |
| } |
| |
| void reportLintWithDescription(AstNode node, String description) { |
| if (node != null) { |
| reporter.reportErrorForNode(new _LintCode(name, description), node, []); |
| } |
| } |
| } |
| |
| class _LintCode extends LintCode { |
| static final registry = <String, LintCode>{}; |
| |
| factory _LintCode(String name, String message) => registry.putIfAbsent( |
| name + message, () => new _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) { |
| TypeProvider typeProvider = context.typeProvider; |
| TypeSystem typeSystem = context.typeSystem; |
| DeclaredVariables declaredVariables = context.declaredVariables; |
| |
| Map<DartObjectImpl, Expression> values = |
| new HashMap<DartObjectImpl, Expression>( |
| equals: (DartObjectImpl key1, DartObjectImpl key2) { |
| DartObjectImpl equals = key1.isIdentical(typeProvider, key2); |
| return equals.isBool && equals.toBoolValue(); |
| }); |
| |
| final ConstantVisitor constantVisitor = new ConstantVisitor( |
| new ConstantEvaluationEngine(typeProvider, declaredVariables, |
| typeSystem: typeSystem), |
| new ErrorReporter( |
| AnalysisErrorListener.NULL_LISTENER, rule.reporter.source)); |
| |
| for (SwitchMember member in node.members) { |
| if (member is SwitchCase) { |
| Expression expression = member.expression; |
| |
| DartObjectImpl result = expression.accept(constantVisitor); |
| |
| if (result == null) { |
| continue; |
| } |
| |
| Expression duplicateValue = values[result]; |
| if (duplicateValue != null) { |
| rule.reportLintWithDescription(member, |
| message(duplicateValue.toString(), expression.toString())); |
| } else { |
| values[result] = expression; |
| } |
| } |
| } |
| } |
| } |