From a90da050ebd925776f0f689abc22f67df0e2ffae Mon Sep 17 00:00:00 2001
From: Vlad Khorsun <hvlad@users.sourceforge.net>
Date: Tue, 14 Apr 2026 15:43:23 +0300
Subject: [PATCH] Use Windows native implementation of condition variables.

---
 src/common/classes/condition.h | 66 +++++-----------------------------
 src/common/classes/locks.h     |  2 ++
 2 files changed, 10 insertions(+), 58 deletions(-)

diff --git a/src/common/classes/condition.h b/src/common/classes/condition.h
index bd943dedfa5..d1c989733ad 100644
--- a/src/common/classes/condition.h
+++ b/src/common/classes/condition.h
@@ -43,50 +43,19 @@ class MemoryPool;
 class Condition
 {
 private:
-	AtomicCounter waiters;
-
-	enum
-	{
-		SIGNAL = 0,
-		BROADCAST,
-		MAX_EVENTS
-	};
-
-	HANDLE events[MAX_EVENTS];
+	CONDITION_VARIABLE m_condvar;
 
 	void init()
 	{
-		events[SIGNAL] = CreateEvent(NULL,  // no security
-			                         FALSE, // auto-reset event
-									 FALSE, // non-signaled initially
-    	                             NULL); // unnamed
-
-		if (!events[SIGNAL])
-			system_call_failed::raise("CreateEvent(SIGNAL)");
-
-		// Create a manual-reset event.
-		events[BROADCAST] = CreateEvent(NULL,  // no security
-    	                                TRUE,  // manual-reset
-    	                                FALSE, // non-signaled initially
-    	                                NULL); // unnamed
-
-		if (!events[BROADCAST])
-		{
-			CloseHandle(events[SIGNAL]);
-			system_call_failed::raise("CreateEvent(BROADCAST)");
-		}
+		InitializeConditionVariable(&m_condvar);
 	}
 
 public:
-	Condition()	{ init(); }
+	Condition() { init(); }
 	explicit Condition(MemoryPool&) { init(); }
 
 	~Condition()
 	{
-		if (events[SIGNAL] && !CloseHandle(events[SIGNAL]))
-			system_call_failed::raise("CloseHandle(SIGNAL)");
-		if (events[BROADCAST] && !CloseHandle(events[BROADCAST]))
-			system_call_failed::raise("CloseHandle(BROADCAST)");
 	}
 
 	// Forbid copying
@@ -95,41 +64,22 @@ class Condition
 
 	void wait(Mutex& m)
 	{
-		++waiters;
-
-		m.leave();
-
-		if (WaitForMultipleObjects((DWORD) MAX_EVENTS, events, FALSE, INFINITE) == WAIT_FAILED)
-			system_call_failed::raise("WaitForMultipleObjects");
-
-		if (--waiters == 0)
-		{
-			if (!ResetEvent(events[BROADCAST]))
-				system_call_failed::raise("ResetEvent(BROADCAST)");
-		}
-
-		m.enter("Condition::wait");
+		if (!SleepConditionVariableCS(&m_condvar, &m.spinlock, INFINITE))
+			system_call_failed::raise("SleepConditionVariableCS");
 	}
 
 	void notifyOne()
 	{
-		if (waiters.value() > 0)
-		{
-			if (!SetEvent(events[SIGNAL]))
-				system_call_failed::raise("SetEvent(SIGNAL)");
-		}
+		WakeConditionVariable(&m_condvar);
 	}
 
 	void notifyAll()
 	{
-		if (waiters.value() > 0)
-		{
-			if (!SetEvent(events[BROADCAST]))
-				system_call_failed::raise("SetEvent");
-		}
+		WakeAllConditionVariable(&m_condvar);
 	}
 };
 
+
 } // namespace Firebird
 
 #else // WIN_NT
diff --git a/src/common/classes/locks.h b/src/common/classes/locks.h
index 2c44ca01df3..f1f56e8c82e 100644
--- a/src/common/classes/locks.h
+++ b/src/common/classes/locks.h
@@ -56,6 +56,8 @@ class Exception;	// Needed for catch
 
 class Mutex : public Reasons
 {
+friend class Condition;
+
 protected:
 	CRITICAL_SECTION spinlock;
 #ifdef DEV_BUILD