+Unity Runtime codeHEADmaster

1 files changed, 53 insertions, 0 deletions

diff --git a/Runtime/Threads/SimpleLock.h b/Runtime/Threads/SimpleLock.h
new file mode 100644
index 0000000..ace47aa
--- /dev/null
+++ b/Runtime/Threads/SimpleLock.h
@@ -0,0 +1,53 @@
+#ifndef SIMPLE_LOCK_H
+#define SIMPLE_LOCK_H
+
+#if SUPPORT_THREADS
+
+#include "AtomicOps.h"
+#include "Semaphore.h"
+
+// Simple, non-recursive mutual exclusion lock. Efficient when there is low contention.
+// First tries to attain lock using atomic ops, then waits for lock using semaphores.
+// Same idea as described here: http://preshing.com/20120226/roll-your-own-lightweight-mutex
+
+class SimpleLock : public NonCopyable
+{
+public:
+	SimpleLock() : m_Count(0) {}
+
+	class AutoLock : public NonCopyable
+	{
+	public:
+		AutoLock( SimpleLock& lock ) : m_Lock(lock)
+		{
+			m_Lock.Lock();
+		}
+
+		~AutoLock()
+		{
+			m_Lock.Unlock();
+		}
+
+	private:
+		SimpleLock& m_Lock;
+	};
+
+	void Lock()
+	{
+		if (AtomicIncrement(&m_Count) != 1)
+			m_Semaphore.WaitForSignal();
+	}
+
+	void Unlock()
+	{
+		if (AtomicDecrement(&m_Count) != 0)
+			m_Semaphore.Signal();
+	}
+
+private:
+	volatile int m_Count;
+	Semaphore m_Semaphore;
+};
+
+#endif // SUPPORT_THREADS
+#endif