trunk/branch integration: ScoppedRWLock

Foundation/src/RWLock.cpp

@@ -38,7 +38,13 @@
 
 
 #if defined(POCO_OS_FAMILY_WINDOWS)
+#if defined(_WIN32_WCE)
+#include "RWLock_WINCE.cpp"
+#else
 #include "RWLock_WIN32.cpp"
+#endif
+#elif defined(POCO_VXWORKS)
+#include "RWLock_VX.cpp"
 #else
 #include "RWLock_POSIX.cpp"
 #endif

Foundation/src/RWLock_WIN32.cpp

@@ -114,22 +114,22 @@ void RWLockImpl::readLockImpl()
 
 bool RWLockImpl::tryReadLockImpl()
 {
-	HANDLE h[2];
+	for (;;)
-	h[0] = _mutex;
-	h[1] = _readEvent;
-	switch (WaitForMultipleObjects(2, h, TRUE, 1))
 	{
-	case WAIT_OBJECT_0:
+		if (_writers != 0 || _writersWaiting != 0)
-	case WAIT_OBJECT_0 + 1:
+			return false;
-		++_readers;
+
-		ResetEvent(_writeEvent);
+		DWORD result = tryReadLockOnce();
-		ReleaseMutex(_mutex);
+		switch (result)
-		poco_assert_dbg(_writers == 0);
+		{
-		return true;
+		case WAIT_OBJECT_0:
-	case WAIT_TIMEOUT:
+		case WAIT_OBJECT_0 + 1:
-		return false;
+			return true;
-	default:
+		case WAIT_TIMEOUT:
-		throw SystemException("cannot lock reader/writer lock");
+			continue; // try again
+		default:
+			throw SystemException("cannot lock reader/writer lock");
+		}
 	}
 }
 
@@ -203,4 +203,27 @@ void RWLockImpl::unlockImpl()
 }
 
 
+DWORD RWLockImpl::tryReadLockOnce()
+{
+	HANDLE h[2];
+	h[0] = _mutex;
+	h[1] = _readEvent;
+	DWORD result = WaitForMultipleObjects(2, h, TRUE, 1); 
+	switch (result)
+	{
+	case WAIT_OBJECT_0:
+	case WAIT_OBJECT_0 + 1:
+		++_readers;
+		ResetEvent(_writeEvent);
+		ReleaseMutex(_mutex);
+		poco_assert_dbg(_writers == 0);
+		return result;
+	case WAIT_TIMEOUT:
+		return result;
+	default:
+		throw SystemException("cannot lock reader/writer lock");
+	}
+}
+
+
 } // namespace Poco