1 files changed, 65 insertions, 0 deletions
diff --git a/LibWinUsb/Main/SafeContextHandle.cs b/LibWinUsb/Main/SafeContextHandle.cs
new file mode 100644
index 0000000..5d0b04e
--- /dev/null
+++ b/LibWinUsb/Main/SafeContextHandle.cs
@@ -0,0 +1,65 @@
+// Copyright � 2006-2010 Travis Robinson. All rights reserved.
+// 
+// website: http://sourceforge.net/projects/libusbdotnet
+// e-mail:  libusbdotnet@gmail.com
+// 
+// This program is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2 of the License, or 
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful, but 
+// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+// 
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, write to the Free Software Foundation, Inc.,
+// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA. or 
+// visit www.gnu.org.
+// 
+// 
+using System;
+using System.Runtime.InteropServices;
+
+namespace LibUsbDotNet.Main
+{
+    /// <summary>
+    /// Base class for all critial handles.
+    /// </summary>
+    public abstract class SafeContextHandle : SafeHandle
+    {
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="pHandle"></param>
+        /// <param name="ownsHandle"></param>
+        protected SafeContextHandle(IntPtr pHandle, bool ownsHandle)
+            : base(IntPtr.Zero, ownsHandle) { SetHandle(pHandle); }
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="pHandleToOwn"></param>
+        protected SafeContextHandle(IntPtr pHandleToOwn)
+            : this(pHandleToOwn, true) { }
+
+        /// <summary>
+        /// Gets a value indicating whether the handle value is invalid.
+        /// </summary>
+        /// <returns>
+        /// true if the handle value is invalid; otherwise, false.
+        /// </returns>
+        /// <PermissionSet><IPermission class="System.Security.Permissions.SecurityPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Flags="UnmanagedCode"/></PermissionSet>
+        public override bool IsInvalid
+        {
+            get
+            {
+                if (handle != IntPtr.Zero)
+                {
+                    return (handle == new IntPtr(-1));
+                }
+                return true;
+            }
+        }
+    }
+}
+\ No newline at end of file