Copied userlandfs code from the test tree to the haiku source tree,

where it will be ported to Haiku.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20216 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/userlandfs/shared/AutoLocker.h

@@ -0,0 +1,164 @@
+// AutoLocker.h
+// 
+// Copyright (c) 2004, Ingo Weinhold ([email protected])
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation 
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+// 
+// Except as contained in this notice, the name of a copyright holder shall
+// not be used in advertising or otherwise to promote the sale, use or other
+// dealings in this Software without prior written authorization of the
+// copyright holder.
+
+#ifndef AUTO_LOCKER_H
+#define AUTO_LOCKER_H
+
+#include <SupportDefs.h>
+
+// locking
+
+// AutoLockerStandardLocking
+template<typename Lockable>
+class AutoLockerStandardLocking {
+public:
+	inline bool Lock(Lockable *lockable)
+	{
+		return lockable->Lock();
+	}
+
+	inline void Unlock(Lockable *lockable)
+	{
+		lockable->Unlock();
+	}
+};
+
+// AutoLockerReadLocking
+template<typename Lockable>
+class AutoLockerReadLocking {
+public:
+	inline bool Lock(Lockable *lockable)
+	{
+		return lockable->ReadLock();
+	}
+
+	inline void Unlock(Lockable *lockable)
+	{
+		lockable->ReadUnlock();
+	}
+};
+
+// AutoLockerWriteLocking
+template<typename Lockable>
+class AutoLockerWriteLocking {
+public:
+	inline bool Lock(Lockable *lockable)
+	{
+		return lockable->WriteLock();
+	}
+
+	inline void Unlock(Lockable *lockable)
+	{
+		lockable->WriteUnlock();
+	}
+};
+
+// AutoLocker
+template<typename Lockable,
+		 typename Locking = AutoLockerStandardLocking<Lockable> >
+class AutoLocker {
+private:
+	typedef AutoLocker<Lockable, Locking>	ThisClass;
+public:
+	inline AutoLocker(Lockable *lockable, bool alreadyLocked = false)
+		: fLockable(lockable),
+		  fLocked(fLockable && alreadyLocked)
+	{
+		if (!fLocked)
+			_Lock();
+	}
+
+	inline AutoLocker(Lockable &lockable, bool alreadyLocked = false)
+		: fLockable(&lockable),
+		  fLocked(fLockable && alreadyLocked)
+	{
+		if (!fLocked)
+			_Lock();
+	}
+
+	inline ~AutoLocker()
+	{
+		Unlock();
+	}
+
+	inline void SetTo(Lockable *lockable, bool alreadyLocked)
+	{
+		Unlock();
+		fLockable = lockable;
+		fLocked = alreadyLocked;
+		if (!fLocked)
+			_Lock();
+	}
+
+	inline void SetTo(Lockable &lockable, bool alreadyLocked)
+	{
+		SetTo(&lockable, alreadyLocked);
+	}
+
+	inline void Unset()
+	{
+		Unlock();
+	}
+
+	inline AutoLocker<Lockable, Locking> &operator=(Lockable *lockable)
+	{
+		SetTo(lockable);
+		return *this;
+	}
+
+	inline AutoLocker<Lockable, Locking> &operator=(Lockable &lockable)
+	{
+		SetTo(&lockable);
+		return *this;
+	}
+
+	inline bool IsLocked() const	{ return fLocked; }
+
+	inline void Unlock()
+	{
+		if (fLockable && fLocked) {
+			fLocking.Unlock(fLockable);
+			fLocked = false;
+		}
+	}
+
+	inline operator bool() const	{ return fLocked; }
+
+private:
+	inline void _Lock()
+	{
+		if (fLockable)
+			fLocked = fLocking.Lock(fLockable);
+	}
+
+private:
+	Lockable	*fLockable;
+	bool		fLocked;
+	Locking		fLocking;
+};
+
+#endif	// AUTO_LOCKER_H