Moved generic auto locking code out of

<disk_device_manager/KDiskDeviceUtils.h> into <util/AutoLock.h>.
Added instantiations for recursive locks (moved from vfs.cpp) and
mutexes.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11157 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/util/AutoLock.h

@@ -0,0 +1,199 @@
+/* 
+ * Copyright 2005, Ingo Weinhold, bonefish@users.sf.net. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+
+#ifndef KERNEL_UTIL_AUTO_LOCKER_H
+#define KERNEL_UTIL_AUTO_LOCKER_H
+
+#include <lock.h>
+
+namespace BPrivate {
+
+// 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 void Unlock()
+	{
+		_Unlock();
+	}
+
+	inline void Detach()
+	{
+		fLockable = NULL;
+		fLocked = false;
+	}
+
+	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 operator bool() const	{ return fLocked; }
+
+private:
+	inline void _Lock()
+	{
+		if (fLockable)
+			fLocked = fLocking.Lock(fLockable);
+	}
+
+	inline void _Unlock()
+	{
+		if (fLockable && fLocked) {
+			fLocking.Unlock(fLockable);
+			fLocked = false;
+		}
+	}
+
+private:
+	Lockable	*fLockable;
+	bool		fLocked;
+	Locking		fLocking;
+};
+
+
+// #pragma mark -
+// #pragma mark ----- instantiations -----
+
+// MutexLocking
+class MutexLocking {
+public:
+	inline bool Lock(mutex *lockable)
+	{
+		mutex_lock(lockable);
+		return true;
+	}
+
+	inline void Unlock(mutex *lockable)
+	{
+		mutex_unlock(lockable);
+	}
+};
+
+// MutexLocker
+typedef AutoLocker<mutex, MutexLocking> MutexLocker;
+
+// RecursiveLockLocking
+class RecursiveLockLocking {
+public:
+	inline bool Lock(recursive_lock *lockable)
+	{
+		recursive_lock_lock(lockable);
+		return true;
+	}
+
+	inline void Unlock(recursive_lock *lockable)
+	{
+		recursive_lock_unlock(lockable);
+	}
+};
+
+// RecursiveLocker
+typedef AutoLocker<recursive_lock, RecursiveLockLocking> RecursiveLocker;
+
+}	// namespace BPrivate
+
+using BPrivate::AutoLocker;
+using BPrivate::MutexLocker;
+using BPrivate::RecursiveLocker;
+
+#endif	// KERNEL_UTIL_AUTO_LOCKER_H