First changeset to make internal message loop non-global.

NTwain.Net35/NTwain.Net35.csproj

@@ -79,6 +79,9 @@
     <Compile Include="..\NTwain\Internals\ITwainSessionInternal.cs">
       <Link>Internals\ITwainSessionInternal.cs</Link>
     </Compile>
+    <Compile Include="..\NTwain\Internals\MESSAGE.cs">
+      <Link>Internals\MESSAGE.cs</Link>
+    </Compile>
     <Compile Include="..\NTwain\Internals\MessageLoop.cs">
       <Link>Internals\MessageLoop.cs</Link>
     </Compile>
@@ -103,6 +106,9 @@
     <Compile Include="..\NTwain\ITwainSession.cs">
       <Link>ITwainSession.cs</Link>
     </Compile>
+    <Compile Include="..\NTwain\IWinMessageFilter.cs">
+      <Link>IWinMessageFilter.cs</Link>
+    </Compile>
     <Compile Include="..\NTwain\Platform.cs">
       <Link>Platform.cs</Link>
     </Compile>

NTwain/IWinMessageFilter.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain
+{
+    /// <summary>
+    /// Interface for checking whether messages from WndProc is a TWAIN message and is handled
+    /// internally.
+    /// </summary>
+    interface IWinMessageFilter
+    {
+        /// <summary>
+        /// Checks and handle the message if it's a TWAIN message.
+        /// </summary>
+        /// <param name="hwnd">The window handle.</param>
+        /// <param name="msg">The message.</param>
+        /// <param name="wParam">The w parameter.</param>
+        /// <param name="lParam">The l parameter.</param>
+        /// <returns>true if handled internally.</returns>
+        bool IsTwainMessage(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam);
+    }
+
+
+}

NTwain/Internals/ITwainSessionInternal.cs

@@ -14,6 +14,8 @@ namespace NTwain.Internals
         /// <returns></returns>
         TWIdentity AppId { get; }
 
+        MessageLoop SelfMessageLoop { get; }
+
         /// <summary>
         /// Gets or sets a value indicating whether calls to triplets will verify the current twain session state.
         /// </summary>

NTwain/Internals/MESSAGE.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace NTwain.Internals
+{
+
+
+    /// <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;
+    }
+}

NTwain/Internals/MessageLoop.cs

@@ -12,18 +12,21 @@ namespace NTwain.Internals
     /// </summary>
     class MessageLoop
     {
-        static MessageLoop _instance = new MessageLoop();
-        public static MessageLoop Instance { get { return _instance; } }
-
         Dispatcher _dispatcher;
         WindowsHook _hook;
-        private MessageLoop() { }
 
-        public void EnsureStarted(WindowsHook.WndProcHook hook)
+        public void Stop()
+        {
+            if (_dispatcher != null)
+            {
+                _dispatcher.InvokeShutdown();
+            }
+        }
+        public void Start(IWinMessageFilter filter)
         {
             if (_dispatcher == null)
             {
-                // using this terrible hack so the new thread will start running before this function returns
+                // using this hack so the new thread will start running before this function returns
                 using (var hack = new WrappedManualResetEvent())
                 {
                     var loopThread = new Thread(new ThreadStart(() =>
@@ -32,11 +35,11 @@ namespace NTwain.Internals
                         _dispatcher = Dispatcher.CurrentDispatcher;
                         if (!Platform.IsOnMono)
                         {
-                            _hook = new WindowsHook(hook);
+                            _hook = new WindowsHook(filter);
                         }
                         hack.Set();
                         Dispatcher.Run();
-                        // if for whatever reason it ever gets here make everything uninitialized
+                        // if dispatcher shutsdown we'll get here so make everything uninitialized
                         _dispatcher = null;
                         if (_hook != null)
                         {

NTwain/Internals/WindowsHook.cs

@@ -13,10 +13,12 @@ namespace NTwain.Internals
     class WindowsHook : IDisposable
     {
         IDisposable _win;
-        WndProcHook _hook;
+        IWinMessageFilter _filter;
 
-        public WindowsHook(WndProcHook hook)
+        public WindowsHook(IWinMessageFilter filter)
         {
+            _filter = filter;
+
             // 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
@@ -27,7 +29,6 @@ namespace NTwain.Internals
                 Handle = win.Handle;
                 win.AddHook(WndProc);
                 _win = win;
-                _hook = hook;
             }
             catch
             {
@@ -36,15 +37,12 @@ namespace NTwain.Internals
             }
         }
 
-        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)
+            if (_filter != null)
             {
-                var winmsg = new MESSAGE(hwnd, msg, wParam, lParam);
+                handled = _filter.IsTwainMessage(hwnd, msg, wParam, lParam);
-                _hook(ref winmsg, ref handled);
             }
             return IntPtr.Zero;
         }
@@ -52,32 +50,6 @@ namespace NTwain.Internals
         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()

NTwain/NTwain.csproj

@@ -61,6 +61,7 @@
     <Compile Include="IMemoryManager.cs" />
     <Compile Include="Internals\ICommittable.cs" />
     <Compile Include="Internals\ITwainSessionInternal.cs" />
+    <Compile Include="Internals\MESSAGE.cs" />
     <Compile Include="Internals\TransferLogic.cs" />
     <Compile Include="Internals\WindowsHook.cs" />
     <Compile Include="Internals\WrappedManualResetEvent.cs" />
@@ -68,6 +69,7 @@
     <Compile Include="Internals\WinMemoryManager.cs" />
     <Compile Include="Internals\MessageLoop.cs" />
     <Compile Include="Internals\UnsafeNativeMethods.cs" />
+    <Compile Include="IWinMessageFilter.cs" />
     <Compile Include="Platform.cs" />
     <Compile Include="Properties\Resources.Designer.cs">
       <AutoGen>True</AutoGen>

NTwain/Properties/VersionInfo.cs

@@ -12,8 +12,8 @@ namespace NTwain
     class _NTwainVersionInfo
     {
         // keep this same in majors releases
-        public const string Release = "1.0.0.0";
+        public const string Release = "2.0.0.0";
         // change this for each nuget release
-        public const string Build = "1.0.2";
+        public const string Build = "2.0.0";
     }
 }

NTwain/TwainSession.cs

@@ -17,7 +17,7 @@ namespace NTwain
     /// <summary>
     /// Basic class for interfacing with TWAIN. You should only have one of this per application process.
     /// </summary>
-    public class TwainSession : ITwainSessionInternal
+    public class TwainSession : ITwainSessionInternal, IWinMessageFilter
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="TwainSession"/> class.
@@ -42,13 +42,14 @@ namespace NTwain
             ((ITwainSessionInternal)this).ChangeState(1, false);
             EnforceState = true;
 
-            MessageLoop.Instance.EnsureStarted(HandleWndProcMessage);
+            _selfMsgLoop = new MessageLoop();
         }
 
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1823:AvoidUnusedPrivateFields")]
         object _callbackObj; // kept around so it doesn't get gc'ed
         TWIdentity _appId;
         TWUserInterface _twui;
+        
 
         static readonly Dictionary<string, TwainSource> __ownedSources = new Dictionary<string, TwainSource>();
 
@@ -62,8 +63,6 @@ namespace NTwain
             return __ownedSources[key] = new TwainSource(session, sourceId);
         }
 
-
-
         /// <summary>
         /// Gets or sets the optional synchronization context.
         /// This allows events to be raised on the thread
@@ -77,6 +76,9 @@ namespace NTwain
 
         #region ITwainSessionInternal Members
 
+        MessageLoop _selfMsgLoop;
+        MessageLoop ITwainSessionInternal.SelfMessageLoop { get { return _selfMsgLoop; } }
+
         /// <summary>
         /// Gets the app id used for the session.
         /// </summary>
@@ -126,6 +128,46 @@ namespace NTwain
             SafeSyncableRaiseOnEvent(OnTransferReady, TransferReady, e);
         }
 
+        DGAudio _dgAudio;
+        DGAudio ITwainSessionInternal.DGAudio
+        {
+            get
+            {
+                if (_dgAudio == null) { _dgAudio = new DGAudio(this); }
+                return _dgAudio;
+            }
+        }
+
+        DGControl _dgControl;
+        DGControl ITwainSessionInternal.DGControl
+        {
+            get
+            {
+                if (_dgControl == null) { _dgControl = new DGControl(this); }
+                return _dgControl;
+            }
+        }
+
+        DGImage _dgImage;
+        DGImage ITwainSessionInternal.DGImage
+        {
+            get
+            {
+                if (_dgImage == null) { _dgImage = new DGImage(this); }
+                return _dgImage;
+            }
+        }
+
+        DGCustom _dgCustom;
+        DGCustom ITwainSessionInternal.DGCustom
+        {
+            get
+            {
+                if (_dgCustom == null) { _dgCustom = new DGCustom(this); }
+                return _dgCustom;
+            }
+        }
+
         #endregion
 
         #region ITwainSession Members
@@ -202,53 +244,6 @@ namespace NTwain
             }
         }
 
-        #endregion
-
-        #region ITwainOperation Members
-
-        DGAudio _dgAudio;
-        /// <summary>
-        /// Gets the triplet operations defined for audio data group.
-        /// </summary>
-        DGAudio ITwainSessionInternal.DGAudio
-        {
-            get
-            {
-                if (_dgAudio == null) { _dgAudio = new DGAudio(this); }
-                return _dgAudio;
-            }
-        }
-
-        DGControl _dgControl;
-        DGControl ITwainSessionInternal.DGControl
-        {
-            get
-            {
-                if (_dgControl == null) { _dgControl = new DGControl(this); }
-                return _dgControl;
-            }
-        }
-
-        DGImage _dgImage;
-        DGImage ITwainSessionInternal.DGImage
-        {
-            get
-            {
-                if (_dgImage == null) { _dgImage = new DGImage(this); }
-                return _dgImage;
-            }
-        }
-
-        DGCustom _dgCustom;
-        DGCustom ITwainSessionInternal.DGCustom
-        {
-            get
-            {
-                if (_dgCustom == null) { _dgCustom = new DGCustom(this); }
-                return _dgCustom;
-            }
-        }
-
         /// <summary>
         /// Opens the data source manager. This must be the first method used
         /// before using other TWAIN functions. Calls to this must be followed by <see cref="Close"/> when done with a TWAIN session.
@@ -256,12 +251,13 @@ namespace NTwain
         /// <returns></returns>
         public ReturnCode Open()
         {
+            _selfMsgLoop.Start(this);
             var rc = ReturnCode.Failure;
-            MessageLoop.Instance.Invoke(() =>
+            _selfMsgLoop.Invoke(() =>
             {
                 Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: OpenManager.", Thread.CurrentThread.ManagedThreadId));
 
-                rc = ((ITwainSessionInternal)this).DGControl.Parent.OpenDsm(MessageLoop.Instance.LoopHandle);
+                rc = ((ITwainSessionInternal)this).DGControl.Parent.OpenDsm(_selfMsgLoop.LoopHandle);
                 if (rc == ReturnCode.Success)
                 {
                     // if twain2 then get memory management functions
@@ -291,14 +287,15 @@ namespace NTwain
         public ReturnCode Close()
         {
             var rc = ReturnCode.Failure;
-            MessageLoop.Instance.Invoke(() =>
+            _selfMsgLoop.Invoke(() =>
             {
                 Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: CloseManager.", Thread.CurrentThread.ManagedThreadId));
 
-                rc = ((ITwainSessionInternal)this).DGControl.Parent.CloseDsm(MessageLoop.Instance.LoopHandle);
+                rc = ((ITwainSessionInternal)this).DGControl.Parent.CloseDsm(_selfMsgLoop.LoopHandle);
                 if (rc == ReturnCode.Success)
                 {
                     Platform.MemoryManager = null;
+                    _selfMsgLoop.Stop();
                 }
             });
             return rc;
@@ -399,7 +396,7 @@ namespace NTwain
         {
             var rc = ReturnCode.Failure;
 
-            MessageLoop.Instance.Invoke(() =>
+            _selfMsgLoop.Invoke(() =>
             {
                 Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: EnableSource.", Thread.CurrentThread.ManagedThreadId));
 
@@ -454,7 +451,7 @@ namespace NTwain
         {
             var rc = ReturnCode.Failure;
 
-            MessageLoop.Instance.Invoke(() =>
+            _selfMsgLoop.Invoke(() =>
             {
                 Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: DisableSource.", Thread.CurrentThread.ManagedThreadId));
 
@@ -495,7 +492,7 @@ namespace NTwain
             // success, the return status from DG_CONTROL / DAT_PENDINGXFERS / MSG_ENDXFER may
             // be ignored.
 
-            MessageLoop.Instance.Invoke(() =>
+            _selfMsgLoop.Invoke(() =>
             {
                 if (targetState < 7)
                 {
@@ -668,8 +665,22 @@ namespace NTwain
 
         #region handle twain ds message
 
-        void HandleWndProcMessage(ref WindowsHook.MESSAGE winMsg, ref bool handled)
+
+        #region IWinMessageFilter Members
+
+        /// <summary>
+        /// Checks and handle the message if it's a TWAIN message.
+        /// </summary>
+        /// <param name="hwnd">The window handle.</param>
+        /// <param name="msg">The message.</param>
+        /// <param name="wParam">The w parameter.</param>
+        /// <param name="lParam">The l parameter.</param>
+        /// <returns>
+        /// true if handled internally.
+        /// </returns>
+        public bool IsTwainMessage(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam)
         {
+            bool handled = false;
             // this handles the message from a typical WndProc message loop and check if it's from the TWAIN source.
             if (_state >= 5)
             {
@@ -677,6 +688,8 @@ namespace NTwain
                 IntPtr msgPtr = IntPtr.Zero;
                 try
                 {
+                    var winMsg = new NTwain.Internals.MESSAGE(hwnd, msg, wParam, lParam);
+
                     // no need to do another lock call when using marshal alloc
                     msgPtr = Marshal.AllocHGlobal(Marshal.SizeOf(winMsg));
                     Marshal.StructureToPtr(winMsg, msgPtr, false);
@@ -695,8 +708,11 @@ namespace NTwain
                     if (msgPtr != IntPtr.Zero) { Marshal.FreeHGlobal(msgPtr); }
                 }
             }
+            return handled;
         }
 
+        #endregion
+
         ReturnCode HandleCallback(TWIdentity origin, TWIdentity destination, DataGroups dg, DataArgumentType dat, Message msg, IntPtr data)
         {
             if (origin != null && CurrentSource != null && origin.Id == CurrentSource.Identity.Id && _state >= 5)
@@ -705,7 +721,7 @@ namespace NTwain
                 // spec says we must handle this on the thread that enabled the DS.
                 // by using the internal dispatcher this will be the case.
 
-                MessageLoop.Instance.BeginInvoke(() =>
+                _selfMsgLoop.BeginInvoke(() =>
                 {
                     HandleSourceMsg(msg);
                 });

NTwain/TwainSource.cs

@@ -32,7 +32,7 @@ namespace NTwain
         public ReturnCode Open()
         {
             var rc = ReturnCode.Failure;
-            MessageLoop.Instance.Invoke(() =>
+            _session.SelfMessageLoop.Invoke(() =>
             {
                 Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: OpenSource.", Thread.CurrentThread.ManagedThreadId));
 
@@ -48,7 +48,7 @@ namespace NTwain
         public ReturnCode Close()
         {
             var rc = ReturnCode.Failure;
-            MessageLoop.Instance.Invoke(() =>
+            _session.SelfMessageLoop.Invoke(() =>
             {
                 Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: CloseSource.", Thread.CurrentThread.ManagedThreadId));
 

Tests/Tester.WPF/ViewModels/TwainVM.cs

@@ -78,7 +78,7 @@ namespace Tester.WPF
                     Format = wantFormat,
                     FileName = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.tif")
                 };
-                var rc = this.DGControl.SetupFileXfer.Set(fileSetup);
+                var rc = this.CurrentSource.DGControl.SetupFileXfer.Set(fileSetup);
             }
         }