| // Copyright (c) 2019, 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. |
| // |
| // Sample illustrating resources are not cleaned up when isolate is shutdown. |
| |
| // @dart = 2.9 |
| |
| import 'dart:io'; |
| import "dart:isolate"; |
| import 'dart:ffi'; |
| |
| import 'package:expect/expect.dart'; |
| |
| import 'pool.dart'; |
| import '../dylib_utils.dart'; |
| |
| void main() { |
| final receiveFromHelper = ReceivePort(); |
| |
| Isolate.spawn(helperIsolateMain, receiveFromHelper.sendPort) |
| .then((helperIsolate) { |
| helperIsolate.addOnExitListener( |
| receiveFromHelper.sendPort, |
| ); |
| print("Main: Helper started."); |
| Pointer<SomeResource> resource; |
| receiveFromHelper.listen((message) { |
| if (message is int) { |
| resource = Pointer<SomeResource>.fromAddress(message); |
| print("Main: Received resource from helper: $resource."); |
| print("Main: Shutting down helper."); |
| helperIsolate.kill(priority: Isolate.immediate); |
| } else { |
| // Isolate kill message. |
| Expect.isNull(message); |
| print("Main: Helper is shut down."); |
| print( |
| "Main: Trying to use resource after isolate that was supposed to free it was shut down."); |
| useResource(resource); |
| print("Main: Releasing resource manually."); |
| releaseResource(resource); |
| print("Main: Shutting down receive port, end of main."); |
| receiveFromHelper.close(); |
| } |
| }); |
| }); |
| } |
| |
| /// If set to `false`, this sample can segfault due to use after free and |
| /// double free. |
| const keepHelperIsolateAlive = true; |
| |
| void helperIsolateMain(SendPort sendToMain) { |
| using((Pool pool) { |
| final resource = pool.using(allocateResource(), releaseResource); |
| pool.onReleaseAll(() { |
| // Will only run print if [keepHelperIsolateAlive] is false. |
| print("Helper: Releasing all resources."); |
| }); |
| print("Helper: Resource allocated."); |
| useResource(resource); |
| print("Helper: Sending resource to main: $resource."); |
| sendToMain.send(resource.address); |
| print("Helper: Going to sleep."); |
| if (keepHelperIsolateAlive) { |
| while (true) { |
| sleep(Duration(seconds: 1)); |
| print("Helper: sleeping."); |
| } |
| } |
| }); |
| } |
| |
| final ffiTestDynamicLibrary = |
| dlopenPlatformSpecific("ffi_test_dynamic_library"); |
| |
| final allocateResource = ffiTestDynamicLibrary.lookupFunction< |
| Pointer<SomeResource> Function(), |
| Pointer<SomeResource> Function()>("AllocateResource"); |
| |
| final useResource = ffiTestDynamicLibrary.lookupFunction< |
| Void Function(Pointer<SomeResource>), |
| void Function(Pointer<SomeResource>)>("UseResource"); |
| |
| final releaseResource = ffiTestDynamicLibrary.lookupFunction< |
| Void Function(Pointer<SomeResource>), |
| void Function(Pointer<SomeResource>)>("ReleaseResource"); |
| |
| /// Represents some opaque resource being managed by a library. |
| class SomeResource extends Opaque {} |