Refactor dispatcher. (#115)

pkgs/leak_tracker/lib/src/leak_tracking/DEPENDENCIES.md

@@ -5,7 +5,6 @@ Dependencies that create loop are markes with `!`.
 
 ```mermaid
 flowchart TD;
-_dispatcher.dart-->_object_tracker.dart;
 _leak_filter.dart-->_object_record.dart;
 _leak_filter.dart-->_primitives;
 _leak_reporter.dart-->_primitives;
@@ -16,7 +15,6 @@ _object_record.dart-->_primitives;
 _object_tracker.dart-->_leak_filter.dart;
 _object_tracker.dart-->_object_record.dart;
 _object_tracker.dart-->_primitives;
-leak_tracking.dart-->_dispatcher.dart;
 leak_tracking.dart-->_leak_tracker.dart;
 leak_tracking.dart-->_primitives;
 orchestration.dart-->_primitives;

pkgs/leak_tracker/lib/src/leak_tracking/_dispatcher.dart → pkgs/leak_tracker/lib/src/leak_tracking/_primitives/_dispatcher.dart

@@ -2,9 +2,6 @@
 // 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 '../shared/_primitives.dart';
-import '_object_tracker.dart';
-
 // Values in [FieldNames] and [EventType] should be identical to ones used in
 // https://github.com/flutter/flutter/blob/a479718b02a818fb4ac8d4900bf08ca389cd8e7d/packages/flutter/lib/src/foundation/memory_allocations.dart#L23
 
@@ -19,12 +16,23 @@ class _EventType {
   static const String disposed = 'disposed';
 }
 
-void dispatchObjectEvent(
-  Map<Object, Map<String, Object>> event,
-  ObjectTracker? objectTracker,
-) {
-  if (objectTracker == null) return;
+typedef StartTrackingCallback = void Function({
+  required Object object,
+  required Map<String, dynamic>? context,
+  required String library,
+  required String className,
+});
 
+typedef DispatchDisposalCallback = void Function({
+  required Object object,
+  required Map<String, dynamic>? context,
+});
+
+void dispatchObjectEvent(
+  Map<Object, Map<String, Object>> event, {
+  required StartTrackingCallback onStartTracking,
+  required DispatchDisposalCallback onDispatchDisposal,
+}) {
   assert(event.length == 1);
   final entry = event.entries.first;
 
@@ -37,14 +45,14 @@ void dispatchObjectEvent(
   final className = fields[_FieldNames.className]?.toString() ?? '';
 
   if (eventType == _EventType.created) {
-    objectTracker.startTracking(
-      object,
+    onStartTracking(
+      object: object,
       context: null,
-      trackedClass:
-          fullClassName(library: libraryName, shortClassName: className),
+      library: libraryName,
+      className: className,
     );
   } else if (eventType == _EventType.disposed) {
-    objectTracker.dispatchDisposal(object, context: null);
+    onDispatchDisposal(object: object, context: null);
   } else {
     throw StateError('Unexpected event type for $object: $eventType.');
   }

pkgs/leak_tracker/lib/src/leak_tracking/leak_tracking.dart

@@ -5,8 +5,8 @@
 import '../devtools_integration/_registration.dart';
 import '../shared/_primitives.dart';
 import '../shared/shared_model.dart';
-import '_dispatcher.dart' as dispatcher;
 import '_leak_tracker.dart';
+import '_primitives/_dispatcher.dart' as dispatcher;
 import '_primitives/model.dart';
 
 /// Provides leak tracking functionality.
@@ -93,7 +93,11 @@ abstract class LeakTracking {
   /// https://github.com/flutter/flutter/blob/a479718b02a818fb4ac8d4900bf08ca389cd8e7d/packages/flutter/lib/src/foundation/memory_allocations.dart#L51
   static void dispatchObjectEvent(Map<Object, Map<String, Object>> event) {
     assert(() {
-      dispatcher.dispatchObjectEvent(event, _leakTracker?.objectTracker);
+      dispatcher.dispatchObjectEvent(
+        event,
+        onStartTracking: dispatchObjectCreated,
+        onDispatchDisposal: dispatchObjectDisposed,
+      );
       return true;
     }());
   }

pkgs/leak_tracker_flutter_test/test/test_infra/event_tracker.dart

@@ -0,0 +1,40 @@
+// Copyright (c) 2022, 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.
+
+enum EventType {
+  started,
+  disposed,
+}
+
+class Event {
+  Event(this.type, this.object, this.context, this.library, this.className);
+
+  final EventType type;
+  final Object object;
+  final Map<String, dynamic>? context;
+  final String? library;
+  final String? className;
+}
+
+class EventTracker {
+  EventTracker();
+
+  final events = <Event>[];
+
+  void dispatchObjectCreated({
+    required String library,
+    required String className,
+    required Object object,
+    Map<String, dynamic>? context,
+  }) {
+    events.add(Event(EventType.started, object, context, library, className));
+  }
+
+  void dispatchObjectDisposed({
+    required Object object,
+    Map<String, dynamic>? context,
+  }) {
+    events.add(Event(EventType.disposed, object, context, null, null));
+  }
+}

pkgs/leak_tracker_flutter_test/test/tests/_dispatcher_test.dart

@@ -6,15 +6,21 @@ import 'dart:ui';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:leak_tracker/src/leak_tracking/_dispatcher.dart';
+import 'package:leak_tracker/src/leak_tracking/_primitives/_dispatcher.dart';
 
-import '../test_infra/mock_object_tracker.dart';
+import '../test_infra/event_tracker.dart';
 
 void main() {
   test('dispatchObjectEvent dispatches Flutter SDK instrumentation.', () {
-    final tracker = MockObjectTracker();
-    MemoryAllocations.instance
-        .addListener((event) => dispatchObjectEvent(event.toMap(), tracker));
+    final tracker = EventTracker();
+
+    MemoryAllocations.instance.addListener(
+      (event) => dispatchObjectEvent(
+        event.toMap(),
+        onStartTracking: tracker.dispatchObjectCreated,
+        onDispatchDisposal: tracker.dispatchObjectDisposed,
+      ),
+    );
 
     final picture = _createPicture();
 
@@ -24,7 +30,8 @@ void main() {
     expect(event.type, EventType.started);
     expect(event.object, picture);
     expect(event.context, null);
-    expect(event.trackedClass, 'dart:ui/Picture');
+    expect(event.className, 'Picture');
+    expect(event.library, 'dart:ui');
 
     picture.dispose();