| // 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/element/type.dart'; |
| |
| import '../analyzer.dart'; |
| import '../extensions.dart'; |
| import '../util/leak_detector_visitor.dart'; |
| |
| const _desc = r'Close instances of `dart:core` `Sink`.'; |
| |
| const _details = r''' |
| **DO** invoke `close` on instances of `dart:core` `Sink`. |
| |
| Closing instances of Sink prevents memory leaks and unexpected behavior. |
| |
| **BAD:** |
| ```dart |
| class A { |
| IOSink _sinkA; |
| void init(filename) { |
| _sinkA = File(filename).openWrite(); // LINT |
| } |
| } |
| ``` |
| |
| **BAD:** |
| ```dart |
| void someFunction() { |
| IOSink _sinkF; // LINT |
| } |
| ``` |
| |
| **GOOD:** |
| ```dart |
| class B { |
| IOSink _sinkB; |
| void init(filename) { |
| _sinkB = File(filename).openWrite(); // OK |
| } |
| |
| void dispose(filename) { |
| _sinkB.close(); |
| } |
| } |
| ``` |
| |
| **GOOD:** |
| ```dart |
| void someFunctionOK() { |
| IOSink _sinkFOK; // OK |
| _sinkFOK.close(); |
| } |
| ``` |
| |
| **Known limitations** |
| |
| This rule does not track all patterns of Sink instantiations and |
| closures. See [linter#1381](https://github.com/dart-lang/linter/issues/1381) |
| for more information. |
| |
| '''; |
| |
| class CloseSinks extends LintRule { |
| static const LintCode code = LintCode( |
| 'close_sinks', "Unclosed instance of 'Sink'.", |
| correctionMessage: |
| "Try invoking 'close' in the function in which the 'Sink' was " |
| 'created.'); |
| |
| CloseSinks() |
| : super( |
| name: 'close_sinks', |
| description: _desc, |
| details: _details, |
| group: Group.errors); |
| |
| @override |
| LintCode get lintCode => code; |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| var visitor = _Visitor(this); |
| registry.addFieldDeclaration(this, visitor); |
| registry.addVariableDeclarationStatement(this, visitor); |
| } |
| } |
| |
| class _Visitor extends LeakDetectorProcessors { |
| static final Map<DartTypePredicate, String> _predicates = { |
| _isSink: 'close', |
| _isSocket: 'destroy', |
| }; |
| |
| _Visitor(super.rule); |
| |
| @override |
| Map<DartTypePredicate, String> get predicates => _predicates; |
| |
| static bool _isSink(DartType type) => |
| type.implementsInterface('Sink', 'dart.core'); |
| |
| static bool _isSocket(DartType type) => |
| type.implementsInterface('Socket', 'dart.io'); |
| } |