[DONT MERGE] give a spec to input files

Yavsc.Abstract/FileSystem/FileSystemHelpers.cs

@@ -0,0 +1,30 @@
+using System.Linq;
+
+namespace Yavsc.Abstract.FileSystem
+{
+    public static class FileSystemHelpers
+    {
+        public static bool IsValidYavscPath(this string path)
+        {
+            if (path == null) return true;
+            foreach (var name in path.Split('/'))
+            {
+                if (!IsValidDirectoryName(name) || name.Equals("..") || name.Equals("."))
+                        return false;
+            }
+            if (path[path.Length]==FileSystemConstants.RemoteDirectorySeparator) return false;
+            return true;
+        }
+        public static bool IsValidDirectoryName(this string name)
+        {
+            return !name.Any(c => !FileSystemConstants.ValidFileNameChars.Contains(c));
+        }
+
+    }
+
+    public static  class FileSystemConstants
+    {
+        public const char RemoteDirectorySeparator = '/';
+        public static char[] ValidFileNameChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-=_~. ".ToCharArray();
+    }
+}