From d900657559422c3b65b044608de2c8ba6290794b Mon Sep 17 00:00:00 2001
From: freyers <bourelly.christophe@gmail.com>
Date: Fri, 15 May 2026 21:12:09 +0000
Subject: [PATCH] fix(semaphore): use absolute deadline for POSIX TimedWait

sem_timedwait takes an absolute CLOCK_REALTIME deadline, but the code
passed a relative duration, placing the deadline near the epoch so the
wait always timed out instantly without blocking on Linux/Android.
Compute the deadline from clock_gettime(CLOCK_REALTIME). Add tests
covering timeout, already-signaled and signaled-before-timeout cases.
---
 CcpSemaphore.cpp       | 16 ++++++++++++++--
 tests/CcpSemaphore.cpp | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/CcpSemaphore.cpp b/CcpSemaphore.cpp
index bf1d6f0..ad58df8 100644
--- a/CcpSemaphore.cpp
+++ b/CcpSemaphore.cpp
@@ -97,6 +97,7 @@ CcpSemaphore::~CcpSemaphore()
 }
 
 #include <errno.h>
+#include <time.h>
 
 bool CcpSemaphore::Wait()
 {
@@ -110,8 +111,19 @@ bool CcpSemaphore::Wait()
 bool CcpSemaphore::TimedWait( uint32_t timeoutInMs )
 {
     timespec ts;
-    ts.tv_sec = timeoutInMs / 1000;
-    ts.tv_nsec = (timeoutInMs % 1000) * 1000000;
+    if( clock_gettime( CLOCK_REALTIME, &ts ) != 0 )
+    {
+        return false;
+    }
+
+    ts.tv_sec += timeoutInMs / 1000;
+    ts.tv_nsec += static_cast<long>( timeoutInMs % 1000 ) * 1000000L;
+    if( ts.tv_nsec >= 1000000000L )
+    {
+        ts.tv_sec += ts.tv_nsec / 1000000000L;
+        ts.tv_nsec %= 1000000000L;
+    }
+
     if( sem_timedwait( &m_semaphore, &ts ) == 0 )
     {
         return true;
diff --git a/tests/CcpSemaphore.cpp b/tests/CcpSemaphore.cpp
index 6d4ed21..595f7e4 100644
--- a/tests/CcpSemaphore.cpp
+++ b/tests/CcpSemaphore.cpp
@@ -78,3 +78,45 @@ TEST( CcpSemaphore, CanWaitOnSemaphore )
 	EXPECT_GT( duration, 200 );
 	EXPECT_LT( duration, 1000 );
 }
+
+TEST( CcpSemaphore, TimedWaitWaitsAndReturnsFalseOnTimeout )
+{
+	CcpSemaphore s;
+
+	bool acquired = true;
+	auto duration = TimeCallInMs( [&] { acquired = s.TimedWait( 500 ); } );
+
+	EXPECT_FALSE( acquired );
+	EXPECT_GT( duration, 250 );
+	EXPECT_LT( duration, 1500 );
+}
+
+TEST( CcpSemaphore, TimedWaitReturnsTrueWhenAlreadySignaled )
+{
+	CcpSemaphore s;
+	s.Signal();
+
+	bool acquired = false;
+	auto duration = TimeCallInMs( [&] { acquired = s.TimedWait( 1000 ); } );
+
+	EXPECT_TRUE( acquired );
+	EXPECT_LT( duration, 100 );
+}
+
+TEST( CcpSemaphore, TimedWaitReturnsTrueWhenSignaledBeforeTimeout )
+{
+	CcpSemaphore s;
+
+	auto thread = [&] {
+		CcpThreadSleep( 200 );
+		s.Signal();
+	};
+	CcpCreateThread( &MakeThread<decltype( thread )>, &thread, CCP_THREAD_PRIORITY_NORMAL );
+
+	bool acquired = false;
+	auto duration = TimeCallInMs( [&] { acquired = s.TimedWait( 2000 ); } );
+
+	EXPECT_TRUE( acquired );
+	EXPECT_GT( duration, 100 );
+	EXPECT_LT( duration, 1500 );
+}