Fix unregister issue

modules/ANSOCR/dllmain.cpp

@@ -17,8 +17,12 @@
 
 // Handle registry with refcount — prevents use-after-free when
 // ReleaseANSOCRHandle is called while inference is still running.
-static std::unordered_map<ANSCENTER::ANSOCRBase*, int>& OCRHandleRegistry() {
-	static std::unordered_map<ANSCENTER::ANSOCRBase*, 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 OCREntry { int refcount; bool destructionStarted; };
+static std::unordered_map<ANSCENTER::ANSOCRBase*, OCREntry>& OCRHandleRegistry() {
+	static std::unordered_map<ANSCENTER::ANSOCRBase*, OCREntry> s;
 	return s;
 }
 static std::mutex& OCRHandleRegistryMutex() {
@@ -32,14 +36,15 @@ static std::condition_variable& OCRHandleRegistryCV() {
 
 static void RegisterOCRHandle(ANSCENTER::ANSOCRBase* h) {
 	std::lock_guard<std::mutex> lk(OCRHandleRegistryMutex());
-	OCRHandleRegistry()[h] = 1;  // refcount = 1
+	OCRHandleRegistry()[h] = { 1, false };
 }
 
 static ANSCENTER::ANSOCRBase* AcquireOCRHandle(ANSCENTER::ANSOCRBase* h) {
 	std::lock_guard<std::mutex> lk(OCRHandleRegistryMutex());
 	auto it = OCRHandleRegistry().find(h);
 	if (it == OCRHandleRegistry().end()) return nullptr;
-	it->second++;
+	if (it->second.destructionStarted) return nullptr;
+	it->second.refcount++;
 	return h;
 }
 
@@ -47,23 +52,25 @@ static bool ReleaseOCRHandleRef(ANSCENTER::ANSOCRBase* h) {
 	std::lock_guard<std::mutex> lk(OCRHandleRegistryMutex());
 	auto it = OCRHandleRegistry().find(h);
 	if (it == OCRHandleRegistry().end()) return false;
-	it->second--;
-	if (it->second <= 0) {
-		OCRHandleRegistry().erase(it);
+	it->second.refcount--;
+	if (it->second.refcount <= 0) {
 		OCRHandleRegistryCV().notify_all();
-		return true;
 	}
-	return false;
+	return false;  // Only Unregister deletes.
 }
 
 static bool UnregisterOCRHandle(ANSCENTER::ANSOCRBase* h) {
 	std::unique_lock<std::mutex> lk(OCRHandleRegistryMutex());
 	auto it = OCRHandleRegistry().find(h);
 	if (it == OCRHandleRegistry().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 = OCRHandleRegistryCV().wait_for(lk, std::chrono::seconds(5), [&]() {
 		auto it2 = OCRHandleRegistry().find(h);
-		return it2 == OCRHandleRegistry().end() || it2->second <= 0;
+		return it2 == OCRHandleRegistry().end() || it2->second.refcount <= 0;
 	});
 	if (!ok) {
 		OutputDebugStringA("WARNING: UnregisterOCRHandle timed out waiting for in-flight inference\n");