Tiny inline class representing a change counter.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@2692 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/registrar/RChangeCounter.h

@@ -0,0 +1,42 @@
+//----------------------------------------------------------------------
+//  This software is part of the OpenBeOS distribution and is covered 
+//  by the OpenBeOS license.
+//---------------------------------------------------------------------
+
+#ifndef CHANGE_COUNTER_H
+#define CHANGE_COUNTER_H
+
+#include <ObjectLocker.h>
+
+class RChangeCounter {
+public:
+	RChangeCounter() : fCount(0), fLocked(0), fChanged(false) {}
+	~RChangeCounter() {}
+
+	int32 Count() const { return fCount; }
+
+	bool Lock() { fLocked++; return true; }
+	void Unlock() { if (fLocked > 0) fLocked--; }
+
+	bool Increment()
+	{
+		bool changed = false;
+		if (fLocked && !fChanged) {
+			fCount++;
+			changed = fChanged = true;
+		}
+		return changed;
+	}
+
+	void Reset() { fCount = 0; fLocked = 0; fChanged = false; }
+
+public:
+	typedef BPrivate::BObjectLocker<RChangeCounter> Locker;
+
+private:
+	int32	fCount;
+	int32	fLocked;
+	bool	fChanged;
+};
+
+#endif	// CHANGE_COUNTER_H