fixing leak when lots of threads are being started and stopped

JetBrains · Nov 24, 2022 · ca1b639 · ca1b639
1 parent 815f11d
commit ca1b639
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Showing 2 changed files with 31 additions and 1 deletion.
diff --git a/src/main/java/com/jetbrains/jdi/VMState.java b/src/main/java/com/jetbrains/jdi/VMState.java
@@ -38,6 +38,8 @@
 
 package com.jetbrains.jdi;
 
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
 import java.lang.ref.WeakReference;
 import java.util.*;
 import java.util.concurrent.CompletableFuture;
@@ -197,8 +199,29 @@ synchronized void referenceTypeRemoved(ReferenceType type) {
         }
     }
 
+    private final ReferenceQueue<VMListener> referenceQueue = new ReferenceQueue<>();
+
+    private boolean hasUnreachableListeners() {
+        boolean res = false;
+        while (referenceQueue.poll() != null) {
+            res = true;
+        }
+        return res;
+    }
+
     synchronized void addListener(VMListener listener) {
-        listeners.add(new WeakReference<>(listener));
+        // remove unreachable
+        if (hasUnreachableListeners()) {
+            Iterator<WeakReference<VMListener>> iter = listeners.iterator();
+            while (iter.hasNext()) {
+                VMListener l = iter.next().get();
+                if (l == null) {
+                    iter.remove();
+                }
+            }
+        }
+
+        listeners.add(new WeakReference<>(listener, referenceQueue));
     }
 
     synchronized boolean hasListener(VMListener listener) {

diff --git a/src/main/java/com/jetbrains/jdi/VirtualMachineImpl.java b/src/main/java/com/jetbrains/jdi/VirtualMachineImpl.java
@@ -1377,10 +1377,17 @@ private void processQueue() {
         //if ((traceFlags & TRACE_OBJREFS) != 0) {
         //    printTrace("Checking for softly reachable objects");
         //}
+        boolean found = false;
         while ((ref = referenceQueue.poll()) != null) {
             SoftObjectReference softRef = (SoftObjectReference)ref;
             removeObjectMirror(softRef);
             batchForDispose(softRef);
+            found = true;
+        }
+
+        if (found) {
+            // we can do that right here as now it is async
+            processBatchedDisposes();
         }
     }