From e45924a30e7d019ec251a86be768af90cf58176f Mon Sep 17 00:00:00 2001
From: Egor Ushakov <egor.ushakov@jetbrains.com>
Date: Tue, 1 Oct 2024 20:02:28 +0200
Subject: [PATCH] [debugger] avoid scanning all classes in vm for nested sub
 classes

GitOrigin-RevId: b2d68e635d37947226c0e53b5a7c4ecd777a8f9a
---
 .../debugger/jdi/VirtualMachineProxyImpl.java | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/java/debugger/impl/src/com/intellij/debugger/jdi/VirtualMachineProxyImpl.java b/java/debugger/impl/src/com/intellij/debugger/jdi/VirtualMachineProxyImpl.java
index 4246648c016a..e8a5f81a0fec 100644
--- a/java/debugger/impl/src/com/intellij/debugger/jdi/VirtualMachineProxyImpl.java
+++ b/java/debugger/impl/src/com/intellij/debugger/jdi/VirtualMachineProxyImpl.java
@@ -15,6 +15,7 @@ import com.intellij.debugger.impl.attach.SAJDWPRemoteConnection;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.ThrowableComputable;
 import com.intellij.util.containers.ContainerUtil;
+import com.jetbrains.jdi.ReferenceTypeImpl;
 import com.jetbrains.jdi.ThreadReferenceImpl;
 import com.sun.jdi.*;
 import com.sun.jdi.request.EventRequestManager;
@@ -111,9 +112,10 @@ public class VirtualMachineProxyImpl implements JdiTimer, VirtualMachineProxy {
 
         if (!candidates.isEmpty()) {
           // keep only direct nested types
+          // do not traverse all classes in vm, only the candidates list
           final Set<ReferenceType> nested2 = new HashSet<>();
           for (final ReferenceType candidate : candidates) {
-            nested2.addAll(nestedTypes(candidate));
+            addNestedTypes(candidate, candidates, nested2);
           }
           candidates.removeAll(nested2);
         }
@@ -128,6 +130,24 @@ public class VirtualMachineProxyImpl implements JdiTimer, VirtualMachineProxy {
     return nestedTypes;
   }
 
+  /**
+   * Check {@link ReferenceTypeImpl#nestedTypes()}
+   */
+  private static void addNestedTypes(ReferenceType base, Collection<ReferenceType> classes, Set<ReferenceType> nested) {
+    String baseName = base.name();
+    int baseLength = baseName.length();
+    classes.forEach(type -> {
+      String name = type.name();
+      int length = name.length();
+      if (length > baseLength && name.startsWith(baseName)) {
+        char c = name.charAt(baseLength);
+        if (c == '$' || c == '#') {
+          nested.add(type);
+        }
+      }
+    });
+  }
+
   @Override
   public List<ReferenceType> allClasses() {
     List<ReferenceType> allClasses = myAllClasses;