From aed6b68d441ef552ec86aa0a18ed3cbc19adf788 Mon Sep 17 00:00:00 2001
From: "Egor.Ushakov" <egor.ushakov@jetbrains.com>
Date: Tue, 6 Jun 2017 15:40:18 +0300
Subject: [PATCH] remember 100 last debugger tree states to keep expansion
 across frames

---
 .../util/resources/misc/registry.properties   |  1 +
 .../impl/frame/XVariablesViewBase.java        | 31 ++++++++++++-------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/platform/util/resources/misc/registry.properties b/platform/util/resources/misc/registry.properties
index 429de9f36601..1e07581f188c 100644
--- a/platform/util/resources/misc/registry.properties
+++ b/platform/util/resources/misc/registry.properties
@@ -277,6 +277,7 @@ debugger.capture.points.annotations=false
 debugger.resume.yourkit.threads=false
 debugger.keep.step.requests=false
 debugger.enable.memory.view=true
+debugger.tree.states.depth=100
 
 analyze.exceptions.on.the.fly=false
 analyze.exceptions.on.the.fly.description=Automatically analyze clipboard on frame activation,\
diff --git a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XVariablesViewBase.java b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XVariablesViewBase.java
index 2474d73f95b3..205f176968c0 100644
--- a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XVariablesViewBase.java
+++ b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XVariablesViewBase.java
@@ -51,18 +51,24 @@ import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 import java.awt.*;
+import java.util.LinkedHashMap;
+import java.util.Map;
 
 /**
  * @author nik
  */
 public abstract class XVariablesViewBase extends XDebugView {
   private final XDebuggerTreePanel myTreePanel;
-  private XDebuggerTreeState myTreeState;
-  private XDebuggerTreeRestorer myTreeRestorer;
-
-  private Object myFrameEqualityObject;
   private MySelectionListener mySelectionListener;
 
+  private XDebuggerTreeRestorer myTreeRestorer;
+  private final Map<Object, XDebuggerTreeState> myTreeStates = new LinkedHashMap<Object, XDebuggerTreeState>() {
+    @Override
+    protected boolean removeEldestEntry(Map.Entry<Object, XDebuggerTreeState> eldest) {
+      return size() > Registry.get("debugger.tree.states.depth").asInteger();
+    }
+  };
+
   protected XVariablesViewBase(@NotNull Project project, @NotNull XDebuggerEditorsProvider editorsProvider, @Nullable XValueMarkers<?, ?> markers) {
     myTreePanel = new XDebuggerTreePanel(
       project, editorsProvider, this, null, this instanceof XWatchesView ? XDebuggerActions.WATCHES_TREE_POPUP_GROUP : XDebuggerActions.VARIABLES_TREE_POPUP_GROUP, markers);
@@ -79,11 +85,14 @@ public abstract class XVariablesViewBase extends XDebugView {
     project.putUserData(XVariablesView.DEBUG_VARIABLES, new XVariablesView.InlineVariablesInfo());
     clearInlays(tree);
     Object newEqualityObject = stackFrame.getEqualityObject();
-    if (myFrameEqualityObject != null && newEqualityObject != null && myFrameEqualityObject.equals(newEqualityObject)
-        && myTreeState != null) {
-      disposeTreeRestorer();
-      myTreeRestorer = myTreeState.restoreState(tree);
+    if (newEqualityObject != null) {
+      XDebuggerTreeState state = myTreeStates.get(newEqualityObject);
+      if (state != null) {
+        disposeTreeRestorer();
+        myTreeRestorer = state.restoreState(tree);
+      }
     }
+
     if (position != null && Registry.is("debugger.valueTooltipAutoShowOnSelection")) {
       registerInlineEvaluator(stackFrame, position, project);
     }
@@ -120,9 +129,9 @@ public abstract class XVariablesViewBase extends XDebugView {
 
   protected void saveCurrentTreeState(@Nullable XStackFrame stackFrame) {
     removeSelectionListener();
-    myFrameEqualityObject = stackFrame != null ? stackFrame.getEqualityObject() : null;
-    if (myTreeRestorer == null || myTreeRestorer.isFinished()) {
-      myTreeState = XDebuggerTreeState.saveState(getTree());
+    Object equalityObject = stackFrame != null ? stackFrame.getEqualityObject() : null;
+    if (equalityObject != null && (myTreeRestorer == null || myTreeRestorer.isFinished())) {
+      myTreeStates.put(equalityObject, XDebuggerTreeState.saveState(getTree()));
     }
     disposeTreeRestorer();
   }