Diff heap statistics.

packages/devtools_app/lib/src/screens/memory/panes/diff/controller/model.dart → packages/devtools_app/lib/src/screens/memory/panes/diff/controller/Item_controller.dart

@@ -11,13 +11,13 @@ import '../../../shared/heap/model.dart';
 import 'heap_diff.dart';
 
 abstract class DiffListItem extends DisposableController {
-  /// Number, that, if shown in name, should be unique in the list.
+  /// Number, that if shown in name, should be unique in the list.
   ///
-  /// If the number is not shown, it should be 0.
+  /// If the number is not expected to be shown in UI, it should be 0.
   int get displayNumber;
 
-  ValueListenable<bool> get isProcessing => _isProcessing;
   final _isProcessing = ValueNotifier<bool>(false);
+  ValueListenable<bool> get isProcessing => _isProcessing;
 
   /// If true, the item contains data, that can be compared and analyzed.
   bool get hasData;
@@ -37,11 +37,16 @@ class SnapshotListItem extends DiffListItem with AutoDisposeControllerMixin {
     this.displayNumber,
     this._isolateName,
     this.diffStore,
+    this.selectedClass,
   ) {
     _isProcessing.value = true;
     receiver.whenComplete(() async {
       final data = await receiver;
-      if (data != null) heap = AdaptedHeap(data);
+      if (data != null) {
+        heap = AdaptedHeap(data);
+        updateSelectedRecord();
+        addAutoDisposeListener(selectedClass, () => updateSelectedRecord());
+      }
       _isProcessing.value = false;
     });
   }
@@ -59,7 +64,17 @@ class SnapshotListItem extends DiffListItem with AutoDisposeControllerMixin {
 
   var sorting = ColumnSorting();
 
-  final diffWith = ValueNotifier<SnapshotListItem?>(null);
+  final _diffWith = ValueNotifier<SnapshotListItem?>(null);
+  ValueListenable<SnapshotListItem?> get diffWith => _diffWith;
+  void setDiffWith(SnapshotListItem? value) {
+    _diffWith.value = value;
+    updateSelectedRecord();
+  }
+
+  final ValueListenable<String?> selectedClass;
+
+  final _selectedRecord = ValueNotifier<HeapStatsRecord?>(null);
+  ValueListenable<HeapStatsRecord?> get selectedRecord => _selectedRecord;
 
   @override
   bool get hasData => heap != null;
@@ -70,6 +85,9 @@ class SnapshotListItem extends DiffListItem with AutoDisposeControllerMixin {
     if (itemToDiffWith == null) return theHeap.stats;
     return diffStore.compare(theHeap, itemToDiffWith.heap!).stats;
   }
+
+  void updateSelectedRecord() =>
+      _selectedRecord.value = statsToShow.recordsByClass[selectedClass.value];
 }
 
 class ColumnSorting {

packages/devtools_app/lib/src/screens/memory/panes/diff/controller/diff_pane_controller.dart

@@ -10,8 +10,8 @@ import 'package:flutter/foundation.dart';
 import '../../../../../primitives/utils.dart';
 import '../../../primitives/memory_utils.dart';
 import '../../../shared/heap/model.dart';
+import 'Item_controller.dart';
 import 'heap_diff.dart';
-import 'model.dart';
 
 class DiffPaneController {
   DiffPaneController(this.snapshotTaker);
@@ -35,7 +35,7 @@ class DiffPaneController {
   DiffListItem get selectedItem => snapshots.value[selectedIndex.value];
 
   /// Full name for the selected class.
-  ValueNotifier<String?> get selectedClass => _selectedClass;
+  ValueListenable<String?> get selectedClass => _selectedClass;
   final _selectedClass = ValueNotifier<String?>(null);
   void setSelectedClass(String? value) => _selectedClass.value = value;
 
@@ -52,6 +52,7 @@ class DiffPaneController {
         _nextDisplayNumber(),
         currentIsolateName ?? '<isolate-not-detected>',
         diffStore,
+        selectedClass,
       ),
     );
     await future;
@@ -61,6 +62,9 @@ class DiffPaneController {
   }
 
   Future<void> clearSnapshots() async {
+    for (var i = 0; i < snapshots.value.length; i++) {
+      snapshots.value[i].dispose();
+    }
     _snapshots.removeRange(1, snapshots.value.length);
     _selectedIndex.value = 0;
   }
@@ -73,6 +77,7 @@ class DiffPaneController {
 
   void deleteCurrentSnapshot() {
     assert(selectedItem is SnapshotListItem);
+    selectedItem.dispose();
     _snapshots.removeRange(selectedIndex.value, selectedIndex.value + 1);
     // We must change the selectedIndex, because otherwise the content will
     // not be re-rendered.

packages/devtools_app/lib/src/screens/memory/panes/diff/controller/heap_diff.dart

@@ -13,8 +13,7 @@ class HeapDiffStore {
 
   HeapComparison compare(AdaptedHeap heap1, AdaptedHeap heap2) {
     final couple = _HeapCouple(heap1, heap2);
-    if (!_store.containsKey(couple)) _store[couple] = HeapComparison(couple);
-    return _store[couple]!;
+    return _store.putIfAbsent(couple, () => HeapComparison(couple));
   }
 }
 
@@ -74,13 +73,16 @@ class HeapComparison {
     final unionOfKeys = older.keys.toSet().union(younger.keys.toSet());
 
     for (var key in unionOfKeys) {
-      if (older.containsKey(key) && younger.containsKey(key)) {
-        final diff = _diffStatsRecords(older[key]!, younger[key]!);
+      final olderRecord = older[key];
+      final youngerRecord = younger[key];
+
+      if (olderRecord != null && youngerRecord != null) {
+        final diff = _diffStatsRecords(olderRecord, youngerRecord);
         if (!diff.isZero) result[key] = diff;
-      } else if (younger.containsKey(key)) {
-        result[key] = younger[key]!;
+      } else if (youngerRecord != null) {
+        result[key] = youngerRecord;
       } else {
-        result[key] = older[key]!.negative();
+        result[key] = olderRecord!.negative();
       }
     }
 

packages/devtools_app/lib/src/screens/memory/panes/diff/diff_pane.dart

@@ -7,8 +7,8 @@ import 'package:flutter/material.dart';
 import '../../../../shared/common_widgets.dart';
 import '../../../../shared/split.dart';
 import '../../../../shared/theme.dart';
+import 'controller/Item_controller.dart';
 import 'controller/diff_pane_controller.dart';
-import 'controller/model.dart';
 import 'widgets/snapshot_control_pane.dart';
 import 'widgets/snapshot_list.dart';
 import 'widgets/snapshot_view.dart';

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/class_details.dart

@@ -6,8 +6,9 @@ import 'package:flutter/widgets.dart';
 
 import '../../../shared/heap/model.dart';
 
-class ClassDetails extends StatelessWidget {
-  const ClassDetails({Key? key, required this.heapClass}) : super(key: key);
+class HeapClassDetails extends StatelessWidget {
+  const HeapClassDetails({Key? key, required this.heapClass}) : super(key: key);
+
   final HeapClass? heapClass;
 
   @override

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/snapshot_control_pane.dart

@@ -7,8 +7,8 @@ import 'package:flutter/material.dart';
 
 import '../../../../../shared/common_widgets.dart';
 import '../../../../../shared/theme.dart';
+import '../controller/Item_controller.dart';
 import '../controller/diff_pane_controller.dart';
-import '../controller/model.dart';
 
 class SnapshotControlPane extends StatelessWidget {
   const SnapshotControlPane({Key? key, required this.controller})
@@ -54,7 +54,7 @@ class _DiffDropdown extends StatelessWidget {
     final diffWith = current.diffWith.value;
     // Check if diffWith was deleted from list.
     if (diffWith != null && !list.value.contains(diffWith)) {
-      current.diffWith.value = null;
+      current.setDiffWith(null);
     }
   }
 
@@ -85,9 +85,9 @@ class _DiffDropdown extends StatelessWidget {
             value: current.diffWith.value ?? current,
             onChanged: (SnapshotListItem? value) {
               if ((value ?? current) == current) {
-                current.diffWith.value = null;
+                current.setDiffWith(null);
               } else {
-                current.diffWith.value = value;
+                current.setDiffWith(value);
               }
             },
             items: items(),

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/snapshot_list.dart

@@ -8,8 +8,8 @@ import '../../../../../primitives/auto_dispose_mixin.dart';
 import '../../../../../shared/common_widgets.dart';
 import '../../../../../shared/table.dart';
 import '../../../../../shared/theme.dart';
+import '../controller/Item_controller.dart';
 import '../controller/diff_pane_controller.dart';
-import '../controller/model.dart';
 
 class SnapshotList extends StatelessWidget {
   const SnapshotList({Key? key, required this.controller}) : super(key: key);

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/snapshot_view.dart

@@ -7,8 +7,8 @@ import 'package:flutter/material.dart';
 import '../../../../../shared/common_widgets.dart';
 import '../../../../../shared/split.dart';
 import '../../../shared/heap/model.dart';
+import '../controller/Item_controller.dart';
 import '../controller/diff_pane_controller.dart';
-import '../controller/model.dart';
 import 'class_details.dart';
 import 'stats_table.dart';
 
@@ -31,6 +31,8 @@ class SnapshotView extends StatelessWidget {
         } else {
           final heap1 = item.heap!;
           final heap2 = item.diffWith.value!.heap!;
+
+          // TODO(polina-c): make comparison async.
           stats = controller.diffStore.compare(heap1, heap2).stats;
         }
 
@@ -54,7 +56,7 @@ class SnapshotView extends StatelessWidget {
                   ),
                 ),
                 const OutlineDecoration(
-                  child: ClassDetails(heapClass: null),
+                  child: HeapClassDetails(heapClass: null),
                 ),
               ],
             );

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/stats_table.dart

@@ -10,8 +10,8 @@ import '../../../../../shared/table.dart';
 import '../../../../../shared/table_data.dart';
 import '../../../../../shared/utils.dart';
 import '../../../shared/heap/model.dart';
+import '../controller/Item_controller.dart';
 import '../controller/diff_pane_controller.dart';
-import '../controller/model.dart';
 
 class _ClassNameColumn extends ColumnData<HeapStatsRecord> {
   _ClassNameColumn()
@@ -125,7 +125,6 @@ class StatsTable extends StatefulWidget {
 class _StatsTableState extends State<StatsTable> with AutoDisposeMixin {
   late final List<ColumnData<HeapStatsRecord>> _columns;
   late final SnapshotListItem _item;
-  final _selectionNotifier = ValueNotifier<HeapStatsRecord?>(null);
 
   @override
   void initState() {
@@ -150,20 +149,6 @@ class _StatsTableState extends State<StatsTable> with AutoDisposeMixin {
     }
   }
 
-  HeapStatsRecord? get _selectedRecord =>
-      _item.statsToShow.recordsByClass[widget.controller.selectedClass.value];
-
-  @override
-  void didChangeDependencies() {
-    super.didChangeDependencies();
-
-    _selectionNotifier.value = _selectedRecord;
-    addAutoDisposeListener(
-      widget.controller.selectedClass,
-      () => _selectionNotifier.value = _selectedRecord,
-    );
-  }
-
   @override
   Widget build(BuildContext context) {
     return FlatTable<HeapStatsRecord>(
@@ -172,7 +157,7 @@ class _StatsTableState extends State<StatsTable> with AutoDisposeMixin {
       keyFactory: (e) => Key(e.heapClass.fullName),
       onItemSelected: (r) =>
           widget.controller.setSelectedClass(r.heapClass.fullName),
-      selectionNotifier: _selectionNotifier,
+      selectionNotifier: _item.selectedRecord,
       sortColumn: _columns[_item.sorting.columnIndex],
       sortDirection: _item.sorting.direction,
       onSortChanged: (

packages/devtools_app/lib/src/screens/memory/shared/heap/model.dart

@@ -30,14 +30,17 @@ class AdaptedHeapData {
     this.created = created ?? DateTime.now();
   }
 
-  factory AdaptedHeapData.fromJson(Map<String, dynamic> json) =>
-      AdaptedHeapData(
-        (json[_JsonFields.objects] as List<dynamic>)
-            .map((e) => AdaptedHeapObject.fromJson(e))
-            .toList(),
-        created: json[_JsonFields.created],
-        rootIndex: json[_JsonFields.rootIndex] ?? _defaultRootIndex,
-      );
+  factory AdaptedHeapData.fromJson(Map<String, dynamic> json) {
+    final createdJson = json[_JsonFields.created];
+
+    return AdaptedHeapData(
+      (json[_JsonFields.objects] as List<dynamic>)
+          .map((e) => AdaptedHeapObject.fromJson(e))
+          .toList(),
+      created: createdJson == null ? null : DateTime.parse(createdJson),
+      rootIndex: json[_JsonFields.rootIndex] ?? _defaultRootIndex,
+    );
+  }
 
   factory AdaptedHeapData.fromHeapSnapshot(HeapSnapshotGraph graph) =>
       AdaptedHeapData(
@@ -70,7 +73,7 @@ class AdaptedHeapData {
   Map<String, dynamic> toJson() => {
         _JsonFields.objects: objects.map((e) => e.toJson()).toList(),
         _JsonFields.rootIndex: rootIndex,
-        _JsonFields.created: created,
+        _JsonFields.created: created.toIso8601String(),
       };
 
   HeapPath? _retainingPath(IdentityHashCode code) {