Add details to diff.

packages/devtools_app/lib/src/primitives/utils.dart

@@ -1501,3 +1501,29 @@ bool isPrimativeInstanceKind(String? kind) {
 /// Returns the file name from a URI or path string, by splitting the [uri] at
 /// the directory separators '/', and returning the last element.
 String? fileNameFromUri(String? uri) => uri?.split('/').last;
+
+/// Calculates subtraction of two maps.
+///
+/// Result map keys is union of the imput maps' keys.
+///
+/// The function invokes:
+/// - `subtract` for values if keys presented in both input maps
+/// - `transform` for keys presented in just `minuend`
+/// - `negate` for keys presented in just `subtrahend`
+Map<K, V2> subtractMaps<K, V1, V2>({
+  required Map<K, V1>? minuend,
+  required Map<K, V1>? subtrahend,
+  required V2? Function(V1? minuend, V1? subtrahend) subtract,
+}) {
+  minuend ??= <K, V1>{};
+  subtrahend ??= <K, V1>{};
+
+  final result = <K, V2>{};
+  final unionOfKeys = minuend.keys.toSet().union(subtrahend.keys.toSet());
+
+  for (var key in unionOfKeys) {
+    final diff = subtract(minuend[key], subtrahend[key]);
+    if (diff != null) result[key] = diff;
+  }
+  return result;
+}

packages/devtools_app/lib/src/screens/memory/memory_heap_tree_view.dart

@@ -454,69 +454,66 @@ class _HeapTreeViewState extends State<HeapTreeView>
       snapshotDisplay = null;
     }
 
-    return Padding(
-      padding: const EdgeInsets.only(top: denseRowSpacing),
-      child: Column(
-        children: [
-          const SizedBox(height: defaultSpacing),
-          ValueListenableBuilder<int>(
-            valueListenable: _currentTab,
-            builder: (context, index, _) => Row(
-              mainAxisAlignment: MainAxisAlignment.spaceBetween,
-              children: [
-                TabBar(
-                  labelColor: themeData.textTheme.bodyLarge!.color,
-                  isScrollable: true,
-                  controller: _tabController,
-                  tabs: _tabs,
-                ),
-                if (_searchableTabs.contains(_tabs[index].key))
-                  _buildSearchFilterControls(),
-              ],
-            ),
+    return Column(
+      children: [
+        const SizedBox(height: defaultSpacing),
+        ValueListenableBuilder<int>(
+          valueListenable: _currentTab,
+          builder: (context, index, _) => Row(
+            mainAxisAlignment: MainAxisAlignment.spaceBetween,
+            children: [
+              TabBar(
+                labelColor: themeData.textTheme.bodyLarge!.color,
+                isScrollable: true,
+                controller: _tabController,
+                tabs: _tabs,
+              ),
+              if (_searchableTabs.contains(_tabs[index].key))
+                _buildSearchFilterControls(),
+            ],
           ),
-          const Divider(),
-          Expanded(
-            child: TabBarView(
-              physics: defaultTabBarViewPhysics,
-              controller: _tabController,
-              children: [
-                // Profile Tab
-                KeepAliveWrapper(
-                  child: AllocationProfileTableView(
-                    controller: controller.allocationProfileController,
-                  ),
+        ),
+        const Divider(),
+        Expanded(
+          child: TabBarView(
+            physics: defaultTabBarViewPhysics,
+            controller: _tabController,
+            children: [
+              // Profile Tab
+              KeepAliveWrapper(
+                child: AllocationProfileTableView(
+                  controller: controller.allocationProfileController,
                 ),
-                const KeepAliveWrapper(
-                  child: AllocationProfileTracingView(),
+              ),
+              const KeepAliveWrapper(
+                child: AllocationProfileTracingView(),
+              ),
+              // Analysis Tab
+              KeepAliveWrapper(
+                child: Column(
+                  children: [
+                    _buildSnapshotControls(themeData.textTheme),
+                    const SizedBox(height: denseRowSpacing),
+                    Expanded(
+                      child: buildSnapshotTables(snapshotDisplay),
+                    ),
+                  ],
                 ),
-                // Analysis Tab
+              ),
+              // Diff tab.
+              if (FeatureFlags.memoryDiffing)
                 KeepAliveWrapper(
-                  child: Column(
-                    children: [
-                      _buildSnapshotControls(themeData.textTheme),
-                      const SizedBox(height: denseRowSpacing),
-                      Expanded(
-                        child: buildSnapshotTables(snapshotDisplay),
-                      ),
-                    ],
+                  child: DiffPane(
+                    controller: controller.diffPaneController,
                   ),
                 ),
-                // Diff tab.
-                if (FeatureFlags.memoryDiffing)
-                  KeepAliveWrapper(
-                    child: DiffPane(
-                      controller: controller.diffPaneController,
-                    ),
-                  ),
-                // Leaks tab.
-                if (controller.shouldShowLeaksTab.value)
-                  const KeepAliveWrapper(child: LeaksPane()),
-              ],
-            ),
+              // Leaks tab.
+              if (controller.shouldShowLeaksTab.value)
+                const KeepAliveWrapper(child: LeaksPane()),
+            ],
           ),
-        ],
-      ),
+        ),
+      ],
     );
   }
 

packages/devtools_app/lib/src/screens/memory/panes/allocation_tracing/allocation_profile_tracing_view_controller.dart

@@ -98,7 +98,7 @@ class AllocationProfileTracingViewController extends DisposableController
 
   void updateClassFilter(String value, {bool force = false}) {
     if (value.isEmpty && _currentFilter.isEmpty && !force) return;
-    final updatedFilter = (value.contains(_currentFilter) && !force
+    final updatedFilteredClassList = (value.contains(_currentFilter) && !force
             ? _filteredClassList.value
             : _unfilteredClassList)
         .where(
@@ -107,7 +107,7 @@ class AllocationProfileTracingViewController extends DisposableController
         .map((e) => _tracedClasses[e.cls.id!]!)
         .toList();
 
-    _filteredClassList.replaceAll(updatedFilter);
+    _filteredClassList.replaceAll(updatedFilteredClassList);
     _currentFilter = value;
   }
 

packages/devtools_app/lib/src/screens/memory/panes/chart/chart_pane.dart

@@ -197,8 +197,6 @@ class _MemoryChartPaneState extends State<MemoryChartPane>
     return ValueListenableBuilder<bool>(
       valueListenable: preferences.memory.showChart,
       builder: (_, showChart, __) {
-        // TODO(polina-c): animate the showing / hiding of this chart.
-
         if (!showChart) return const SizedBox.shrink();
 
         return RawKeyboardListener(

packages/devtools_app/lib/src/screens/memory/panes/control/chart_button.dart

@@ -0,0 +1,29 @@
+// Copyright 2019 The Chromium Authors. 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:flutter/material.dart';
+
+import '../../../../shared/common_widgets.dart';
+import '../../../../shared/globals.dart';
+import '../../primitives/ui.dart';
+
+class ChartButton extends StatelessWidget {
+  const ChartButton({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return ValueListenableBuilder<bool>(
+      valueListenable: preferences.memory.showChart,
+      builder: (_, showChart, __) => IconLabelButton(
+        key: key,
+        tooltip: showChart ? 'Hide chart' : 'Show chart',
+        icon: showChart ? Icons.keyboard_arrow_up : Icons.keyboard_arrow_down,
+        label: 'Chart',
+        minScreenWidthForTextBeforeScaling: primaryControlsMinVerboseWidth,
+        onPressed: () => preferences.memory.showChart.value =
+            !preferences.memory.showChart.value,
+      ),
+    );
+  }
+}

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

@@ -23,46 +23,75 @@ class DiffPaneController {
 
   /// The list contains one item that show information and all others
   /// are snapshots.
-  ValueListenable<List<DiffListItem>> get snapshots => _snapshots;
-  final _snapshots = ListValueNotifier(<DiffListItem>[InformationListItem()]);
+  ValueListenable<List<SnapshotItem>> get snapshots => _snapshots;
+  final _snapshots = ListValueNotifier(<SnapshotItem>[SnapshotDocItem()]);
 
-  ValueListenable<int> get selectedIndex => _selectedIndex;
-  final _selectedIndex = ValueNotifier<int>(0);
+  ValueListenable<int> get selectedSnapshotIndex => _selectedSnapshotIndex;
+  final _selectedSnapshotIndex = ValueNotifier<int>(0);
+  void setSelectedSnapshotIndex(int index) =>
+      _selectedSnapshotIndex.value = index;
 
   /// If true, some process is going on.
   ValueListenable<bool> get isProcessing => _isProcessing;
   final _isProcessing = ValueNotifier<bool>(false);
 
-  DiffListItem get selectedItem => snapshots.value[selectedIndex.value];
+  SnapshotItem get selectedSnapshotItem =>
+      snapshots.value[selectedSnapshotIndex.value];
 
   /// Full name for the selected class.
-  ValueListenable<String?> get selectedClass => _selectedClass;
-  final _selectedClass = ValueNotifier<String?>(null);
-  void setSelectedClass(String? value) => _selectedClass.value = value;
+  ValueListenable<HeapClassName?> get selectedClass => _selectedClass;
+  final _selectedClass = ValueNotifier<HeapClassName?>(null);
+  void setSelectedClass(HeapClassName? value) => _selectedClass.value = value;
+
+  /// Selected retaining path.
+  ValueListenable<ClassOnlyHeapPath?> get selectedPath => _selectedPath;
+  final _selectedPath = ValueNotifier<ClassOnlyHeapPath?>(null);
+  void setselectedPath(ClassOnlyHeapPath? value) => _selectedPath.value = value;
+
+  ValueListenable<String?> get classFilter => _classFilter;
+  final _classFilter = ValueNotifier<String?>(null);
+  void setClassFilter(String value) {
+    _classFilter.value = value;
+    throw UnimplementedError();
+    // if (value.isEmpty && _currentFilter.isEmpty) return;
+    // final updatedFilteredClassList = (value.contains(_currentFilter)
+    //     ? _filteredClassList.value
+    //     : _unfilteredClassList)
+    //     .where(
+    //       (e) => e.cls.name!.contains(value),
+    // )
+    //     .map((e) => _tracedClasses[e.cls.id!]!)
+    //     .toList();
+    //
+    // _filteredClassList.replaceAll(updatedFilteredClassList);
+    // _currentFilter = value;
+  }
 
   /// True, if the list contains snapshots, i.e. items beyond the first
   /// informational item.
   bool get hasSnapshots => snapshots.value.length > 1;
 
-  final snapshotStatsSorting = ColumnSorting();
+  final classSorting = ColumnSorting();
+
+  final classDiffSorting = ColumnSorting();
 
-  final classStatsSorting = ColumnSorting();
+  final pathSorting = ColumnSorting();
 
   Future<void> takeSnapshot() async {
     _isProcessing.value = true;
     final future = snapshotTaker.take();
-    _snapshots.add(
-      SnapshotListItem(
-        future,
-        _nextDisplayNumber(),
-        currentIsolateName ?? '<isolate-not-detected>',
-        diffStore,
-        selectedClass,
-      ),
+    final newItem = SnapshotInstanceItem(
+      future,
+      _nextDisplayNumber(),
+      currentIsolateName ?? '<isolate-not-detected>',
+      diffStore,
+      selectedClass,
+      selectedPath,
     );
+    _snapshots.add(newItem);
     await future;
     final newElementIndex = snapshots.value.length - 1;
-    _selectedIndex.value = newElementIndex;
+    _selectedSnapshotIndex.value = newElementIndex;
     _isProcessing.value = false;
   }
 
@@ -71,7 +100,7 @@ class DiffPaneController {
       snapshots.value[i].dispose();
     }
     _snapshots.removeRange(1, snapshots.value.length);
-    _selectedIndex.value = 0;
+    _selectedSnapshotIndex.value = 0;
   }
 
   int _nextDisplayNumber() {
@@ -81,15 +110,14 @@ class DiffPaneController {
   }
 
   void deleteCurrentSnapshot() {
-    assert(selectedItem is SnapshotListItem);
-    selectedItem.dispose();
-    _snapshots.removeRange(selectedIndex.value, selectedIndex.value + 1);
+    assert(selectedSnapshotItem is SnapshotInstanceItem);
+    selectedSnapshotItem.dispose();
+    _snapshots.removeRange(
+      selectedSnapshotIndex.value,
+      selectedSnapshotIndex.value + 1,
+    );
     // We must change the selectedIndex, because otherwise the content will
     // not be re-rendered.
-    _selectedIndex.value = max(selectedIndex.value - 1, 0);
-  }
-
-  void select(int index) {
-    _selectedIndex.value = index;
+    _selectedSnapshotIndex.value = max(selectedSnapshotIndex.value - 1, 0);
   }
 }