Fix unregister issue

modules/ANSTrainingEngine/ANSTrainingEngine.cpp

@@ -20,8 +20,12 @@
 
 // Handle registry with refcount — prevents use-after-free when
 // ReleaseANSTREHandle is called while an operation is still running.
-static std::unordered_map<ANSCENTER::ANSTRE*, int>& TREHandleRegistry() {
-    static std::unordered_map<ANSCENTER::ANSTRE*, int> s;
+// destructionStarted: set by the first Unregister caller; blocks new Acquires
+// and makes subsequent Unregister calls return false without deleting.
+// Prevents double-free when Release is raced on the same handle.
+struct TREEntry { int refcount; bool destructionStarted; };
+static std::unordered_map<ANSCENTER::ANSTRE*, TREEntry>& TREHandleRegistry() {
+    static std::unordered_map<ANSCENTER::ANSTRE*, TREEntry> s;
     return s;
 }
 static std::mutex& TREHandleRegistryMutex() {
@@ -35,14 +39,15 @@ static std::condition_variable& TREHandleRegistryCV() {
 
 static void RegisterTREHandle(ANSCENTER::ANSTRE* h) {
     std::lock_guard<std::mutex> lk(TREHandleRegistryMutex());
-    TREHandleRegistry()[h] = 1;
+    TREHandleRegistry()[h] = { 1, false };
 }
 
 static ANSCENTER::ANSTRE* AcquireTREHandle(ANSCENTER::ANSTRE* h) {
     std::lock_guard<std::mutex> lk(TREHandleRegistryMutex());
     auto it = TREHandleRegistry().find(h);
     if (it == TREHandleRegistry().end()) return nullptr;
-    it->second++;
+    if (it->second.destructionStarted) return nullptr;
+    it->second.refcount++;
     return h;
 }
 
@@ -50,23 +55,25 @@ static bool ReleaseTREHandleRef(ANSCENTER::ANSTRE* h) {
     std::lock_guard<std::mutex> lk(TREHandleRegistryMutex());
     auto it = TREHandleRegistry().find(h);
     if (it == TREHandleRegistry().end()) return false;
-    it->second--;
-    if (it->second <= 0) {
-        TREHandleRegistry().erase(it);
+    it->second.refcount--;
+    if (it->second.refcount <= 0) {
         TREHandleRegistryCV().notify_all();
-        return true;
     }
-    return false;
+    return false;  // Only Unregister deletes.
 }
 
 static bool UnregisterTREHandle(ANSCENTER::ANSTRE* h) {
     std::unique_lock<std::mutex> lk(TREHandleRegistryMutex());
     auto it = TREHandleRegistry().find(h);
     if (it == TREHandleRegistry().end()) return false;
-    it->second--;
+    if (it->second.destructionStarted) {
+        return false;  // Another thread already owns the delete.
+    }
+    it->second.destructionStarted = true;
+    it->second.refcount--;
     bool ok = TREHandleRegistryCV().wait_for(lk, std::chrono::seconds(30), [&]() {
         auto it2 = TREHandleRegistry().find(h);
-        return it2 == TREHandleRegistry().end() || it2->second <= 0;
+        return it2 == TREHandleRegistry().end() || it2->second.refcount <= 0;
     });
     if (!ok) {
         OutputDebugStringA("WARNING: UnregisterTREHandle timed out waiting for in-flight operations\n");