Added SetTo() methods to the AutoLocker.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4221 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/disk_device_manager/KDiskDeviceUtils.h

@@ -155,18 +155,30 @@ public:
 		_Unlock();
 	}
 
-	inline AutoLocker<Lockable, Locking> &operator=(Lockable *lockable)
+	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 AutoLocker<Lockable, Locking> &operator=(Lockable *lockable)
+	{
+		SetTo(lockable);
+		return *this;
+	}
+
 	inline AutoLocker<Lockable, Locking> &operator=(Lockable &lockable)
 	{
-		_Unlock();
+		SetTo(&lockable);
-		fLockable = &lockable;
+		return *this;
-		_Lock();
 	}
 
 	inline bool IsLocked() const	{ return fLocked; }