Road to v1 begins!

NTwain/Internals/WindowsHook.cs

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+using System;
+using System.Runtime.InteropServices;
+using System.Windows.Interop;
+
+namespace NTwain.Internals
+{
+
+    /// <summary>
+    /// Abstracts out wnd proc hook on Windows from MessageLoop class.
+    /// This allows things to not depend on PresentationCore.dll at runtime on mono.
+    /// Not that everything works yet in mono but it's something.
+    /// </summary>
+    class WindowsHook : IDisposable
+    {
+        IDisposable _win;
+        WndProcHook _hook;
+
+        public WindowsHook(WndProcHook hook)
+        {
+            // hook into windows msg loop for old twain to post msgs.
+            // the style values are purely guesses here with
+            // CS_NOCLOSE, WS_DISABLED, and WS_EX_NOACTIVATE
+            HwndSource win = null;
+            try
+            {
+                win = new HwndSource(0x0200, 0x8000000, 0x8000000, 0, 0, "NTWAIN_LOOPER", IntPtr.Zero);
+                Handle = win.Handle;
+                win.AddHook(WndProc);
+                _win = win;
+                _hook = hook;
+            }
+            catch
+            {
+                if (win != null) { win.Dispose(); }
+            }
+        }
+
+        public delegate void WndProcHook(ref MESSAGE winMsg, ref bool handled);
+
+
+        private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
+        {
+            if (_hook != null)
+            {
+                var winmsg = new MESSAGE(hwnd, msg, wParam, lParam);
+                _hook(ref winmsg, ref handled);
+            }
+            return IntPtr.Zero;
+        }
+
+        public IntPtr Handle { get; private set; }
+
+
+        /// <summary>
+        /// The MSG structure in Windows for TWAIN use.
+        /// </summary>
+        [StructLayout(LayoutKind.Sequential)]
+        public struct MESSAGE
+        {
+            public MESSAGE(IntPtr hwnd, int message, IntPtr wParam, IntPtr lParam)
+            {
+                _hwnd = hwnd;
+                _message = (uint)message;
+                _wParam = wParam;
+                _lParam = lParam;
+                _time = 0;
+                _x = 0;
+                _y = 0;
+            }
+
+            IntPtr _hwnd;
+            uint _message;
+            IntPtr _wParam;
+            IntPtr _lParam;
+            uint _time;
+            int _x;
+            int _y;
+        }
+
+        #region IDisposable Members
+
+        public void Dispose()
+        {
+            if (_win != null)
+            {
+                ((HwndSource)_win).RemoveHook(WndProc);
+                _win.Dispose();
+                _win = null;
+            }
+        }
+
+        #endregion
+    }
+}