Fix unregister issue

modules/ANSFR/dllmain.cpp

@@ -28,8 +28,12 @@ std::atomic<bool> g_forceNoPool{false};
 
 // Handle registry with refcount — prevents use-after-free when
 // ReleaseANSRFHandle is called while inference is still running.
-static std::unordered_map<ANSCENTER::ANSFacialRecognition*, int>& FRHandleRegistry() {
-    static std::unordered_map<ANSCENTER::ANSFacialRecognition*, 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 FREntry { int refcount; bool destructionStarted; };
+static std::unordered_map<ANSCENTER::ANSFacialRecognition*, FREntry>& FRHandleRegistry() {
+    static std::unordered_map<ANSCENTER::ANSFacialRecognition*, FREntry> s;
     return s;
 }
 static std::mutex& FRHandleRegistryMutex() {
@@ -43,14 +47,15 @@ static std::condition_variable& FRHandleRegistryCV() {
 
 static void RegisterFRHandle(ANSCENTER::ANSFacialRecognition* h) {
     std::lock_guard<std::mutex> lk(FRHandleRegistryMutex());
-    FRHandleRegistry()[h] = 1;
+    FRHandleRegistry()[h] = { 1, false };
 }
 
 static ANSCENTER::ANSFacialRecognition* AcquireFRHandle(ANSCENTER::ANSFacialRecognition* h) {
     std::lock_guard<std::mutex> lk(FRHandleRegistryMutex());
     auto it = FRHandleRegistry().find(h);
     if (it == FRHandleRegistry().end()) return nullptr;
-    it->second++;
+    if (it->second.destructionStarted) return nullptr;
+    it->second.refcount++;
     return h;
 }
 
@@ -58,23 +63,25 @@ static bool ReleaseFRHandleRef(ANSCENTER::ANSFacialRecognition* h) {
     std::lock_guard<std::mutex> lk(FRHandleRegistryMutex());
     auto it = FRHandleRegistry().find(h);
     if (it == FRHandleRegistry().end()) return false;
-    it->second--;
-    if (it->second <= 0) {
-        FRHandleRegistry().erase(it);
+    it->second.refcount--;
+    if (it->second.refcount <= 0) {
         FRHandleRegistryCV().notify_all();
-        return true;
     }
-    return false;
+    return false;  // Only Unregister deletes.
 }
 
 static bool UnregisterFRHandle(ANSCENTER::ANSFacialRecognition* h) {
     std::unique_lock<std::mutex> lk(FRHandleRegistryMutex());
     auto it = FRHandleRegistry().find(h);
     if (it == FRHandleRegistry().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 = FRHandleRegistryCV().wait_for(lk, std::chrono::seconds(30), [&]() {
         auto it2 = FRHandleRegistry().find(h);
-        return it2 == FRHandleRegistry().end() || it2->second <= 0;
+        return it2 == FRHandleRegistry().end() || it2->second.refcount <= 0;
     });
     if (!ok) {
         OutputDebugStringA("WARNING: UnregisterFRHandle timed out waiting for in-flight inference\n");