Transfer logic tweaks for #42

src/NTwain/DataSource.cs

@@ -297,6 +297,14 @@ namespace NTwain
             }
         }
 
+        internal DGAudio DGAudio
+        {
+            get
+            {
+                return _session.DGAudio;
+            }
+        }
+
         #endregion
 
         //#region INotifyPropertyChanged Members

src/NTwain/DataTransferredEventArgs.cs

@@ -23,25 +23,21 @@ namespace NTwain
         /// </summary>
         /// <param name="source">The source.</param>
         /// <param name="nativeData">The native data.</param>
-        /// <param name="imageInfo">The image information.</param>
+        public DataTransferredEventArgs(DataSource source, IntPtr nativeData)
-        public DataTransferredEventArgs(DataSource source, IntPtr nativeData, TWImageInfo imageInfo)
         {
             DataSource = source;
             NativeData = nativeData;
-            ImageInfo = imageInfo;
         }
         /// <summary>
         /// Initializes a new instance of the <see cref="DataTransferredEventArgs"/> class.
         /// </summary>
         /// <param name="source">The source.</param>
         /// <param name="fileDataPath">The file data path.</param>
-        /// <param name="imageInfo">The image information.</param>
         /// <param name="imageFileFormat">The image file format.</param>
-        public DataTransferredEventArgs(DataSource source, string fileDataPath, TWImageInfo imageInfo, FileFormat imageFileFormat)
+        public DataTransferredEventArgs(DataSource source, string fileDataPath, FileFormat imageFileFormat)
         {
             DataSource = source;
             FileDataPath = fileDataPath;
-            ImageInfo = imageInfo;
             ImageFileFormat = imageFileFormat;
         }
         /// <summary>
@@ -49,12 +45,10 @@ namespace NTwain
         /// </summary>
         /// <param name="source">The source.</param>
         /// <param name="memoryData">The memory data.</param>
-        /// <param name="imageInfo">The image information.</param>
+        public DataTransferredEventArgs(DataSource source, byte[] memoryData)
-        public DataTransferredEventArgs(DataSource source, byte[] memoryData, TWImageInfo imageInfo)
         {
             DataSource = source;
             MemoryData = memoryData;
-            ImageInfo = imageInfo;
         }
 
         /// <summary>
@@ -94,13 +88,27 @@ namespace NTwain
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1819:PropertiesShouldNotReturnArrays")]
         public byte[] MemoryData { get; private set; }
 
+        TWImageInfo _imgInfo;
         /// <summary>
         /// Gets the final image information if applicable.
         /// </summary>
         /// <value>
         /// The final image information.
         /// </value>
-        public TWImageInfo ImageInfo { get; private set; }
+        public TWImageInfo ImageInfo
+        {
+            get
+            {
+                if (_imgInfo == null)
+                {
+                    if (DataSource.DGImage.ImageInfo.Get(out _imgInfo) != ReturnCode.Success)
+                    {
+                        _imgInfo = null;
+                    }
+                }
+                return _imgInfo;
+            }
+        }
 
         /// <summary>
         /// Gets the data source.

src/NTwain/Internals/TransferLogic.cs

@@ -19,37 +19,37 @@ namespace NTwain.Internals
         /// </summary>
         public static void DoTransferRoutine(ITwainSessionInternal session)
         {
+            #region get xfer types
+
+            bool xferImage = true; // default to always xfer image
+            bool xferAudio = false;
+            DataGroups xferGroup = DataGroups.None;
+            XferMech imgXferMech = XferMech.Native;
+            XferMech audXferMech = XferMech.Native;
+            if (session.DGControl.XferGroup.Get(ref xferGroup) == ReturnCode.Success)
+            {
+                xferAudio = (xferGroup & DataGroups.Audio) == DataGroups.Audio;
+                xferImage = xferGroup == DataGroups.None || (xferGroup & DataGroups.Image) == DataGroups.Image;
+            }
+            // some DS end up getting none but we will assume it's image
+            if (xferImage)
+            {
+                imgXferMech = session.CurrentSource.Capabilities.ICapXferMech.GetCurrent();
+            }
+            if (xferAudio)
+            {
+                var mech = session.CurrentSource.Capabilities.ACapXferMech.GetCurrent();
+            }
+
+            #endregion
+
             var pending = new TWPendingXfers();
-            //var rc = ReturnCode.Success;
             var rc = session.DGControl.PendingXfers.Get(pending);
             do
             {
-                #region build and raise xfer ready
+                #region raise xfer ready
 
-                bool xferImage = true; // default to always xfer image
+                var preXferArgs = new TransferReadyEventArgs(session.CurrentSource, pending.Count, pending.EndOfJob == 0); ;
-                bool xferAudio = false;
-                DataGroups xferGroup = DataGroups.None;
-                if (session.DGControl.XferGroup.Get(ref xferGroup) == ReturnCode.Success)
-                {
-                    xferAudio = (xferGroup & DataGroups.Audio) == DataGroups.Audio;
-                    xferImage = xferGroup == DataGroups.None || (xferGroup & DataGroups.Image) == DataGroups.Image;
-                }
-
-
-                TWAudioInfo audInfo = null;
-                if (xferAudio && session.DGAudio.AudioInfo.Get(out audInfo) != ReturnCode.Success)
-                {
-                    audInfo = null;
-                }
-
-                TWImageInfo imgInfo = null;
-                if (xferImage && session.DGImage.ImageInfo.Get(out imgInfo) != ReturnCode.Success)
-                {
-                    imgInfo = null;
-                }
-
-                // ask consumer for xfer details
-                var preXferArgs = new TransferReadyEventArgs(pending.Count, pending.EndOfJob == 0, imgInfo, audInfo); ;
                 session.SafeSyncableRaiseEvent(preXferArgs);
 
                 #endregion
@@ -64,13 +64,9 @@ namespace NTwain.Internals
                 {
                     if (!preXferArgs.CancelCurrent)
                     {
-
-                        // some DS end up getting none but we will assume it's image
                         if (xferImage)
                         {
-                            var mech = session.CurrentSource.Capabilities.ICapXferMech.GetCurrent();
+                            switch (imgXferMech)
-
-                            switch (mech)
                             {
                                 case XferMech.Memory:
                                     DoImageMemoryXfer(session);
@@ -85,13 +81,11 @@ namespace NTwain.Internals
                                 default: // always assume native
                                     DoImageNativeXfer(session);
                                     break;
-
                             }
                         }
                         if (xferAudio)
                         {
-                            var mech = session.CurrentSource.Capabilities.ACapXferMech.GetCurrent();
+                            switch (audXferMech)
-                            switch (mech)
                             {
                                 case XferMech.File:
                                     DoAudioFileXfer(session);
@@ -135,7 +129,7 @@ namespace NTwain.Internals
                         lockedPtr = PlatformInfo.Current.MemoryManager.Lock(dataPtr);
                     }
 
-                    session.SafeSyncableRaiseEvent(new DataTransferredEventArgs(session.CurrentSource, lockedPtr, null));
+                    session.SafeSyncableRaiseEvent(new DataTransferredEventArgs(session.CurrentSource, lockedPtr));
                 }
                 else
                 {
@@ -176,7 +170,7 @@ namespace NTwain.Internals
             var xrc = session.DGAudio.AudioFileXfer.Get();
             if (xrc == ReturnCode.XferDone)
             {
-                session.SafeSyncableRaiseEvent(new DataTransferredEventArgs(session.CurrentSource, filePath, null, (FileFormat)0));
+                session.SafeSyncableRaiseEvent(new DataTransferredEventArgs(session.CurrentSource, filePath, (FileFormat)0));
             }
             else
             {
@@ -421,23 +415,18 @@ namespace NTwain.Internals
         static void DoImageXferredEventRoutine(ITwainSessionInternal session, IntPtr dataPtr, byte[] dataArray, string filePath, FileFormat format)
         {
             DataTransferredEventArgs args = null;
-            TWImageInfo imgInfo;
 
-            if (session.DGImage.ImageInfo.Get(out imgInfo) != ReturnCode.Success)
-            {
-                imgInfo = null;
-            }
             if (dataPtr != IntPtr.Zero)
             {
-                args = new DataTransferredEventArgs(session.CurrentSource, dataPtr, imgInfo);
+                args = new DataTransferredEventArgs(session.CurrentSource, dataPtr);
             }
             else if (dataArray != null)
             {
-                args = new DataTransferredEventArgs(session.CurrentSource, dataArray, imgInfo);
+                args = new DataTransferredEventArgs(session.CurrentSource, dataArray);
             }
             else
             {
-                args = new DataTransferredEventArgs(session.CurrentSource, filePath, imgInfo, format);
+                args = new DataTransferredEventArgs(session.CurrentSource, filePath, format);
             }
             session.SafeSyncableRaiseEvent(args);
         }

src/NTwain/TransferReadyEventArgs.cs

@@ -11,18 +11,24 @@ namespace NTwain
         /// <summary>
         /// Initializes a new instance of the <see cref="TransferReadyEventArgs"/> class.
         /// </summary>
+        /// <param name="source">The source.</param>
         /// <param name="pendingCount">The pending count.</param>
-        /// <param name="endOfJob">if set to <c>true</c> [end of job].</param>
+        /// <param name="endOfJob">if set to <c>true</c> then it's the end of job.</param>
-        /// <param name="imageInfo">The image information.</param>
+        public TransferReadyEventArgs(DataSource source, int pendingCount, bool endOfJob)
-        /// <param name="audioInfo">The audio information.</param>
-        public TransferReadyEventArgs(int pendingCount, bool endOfJob, TWImageInfo imageInfo, TWAudioInfo audioInfo)
         {
+            DataSource = source;
             PendingTransferCount = pendingCount;
             EndOfJob = endOfJob;
-            PendingImageInfo = imageInfo;
-            AudioInfo = audioInfo;
         }
 
+        /// <summary>
+        /// Gets the data source.
+        /// </summary>
+        /// <value>
+        /// The data source.
+        /// </value>
+        public DataSource DataSource { get; private set; }
+
         /// <summary>
         /// Gets or sets a value indicating whether the current transfer should be canceled
         /// and continue next transfer if there are more data.
@@ -49,6 +55,7 @@ namespace NTwain
         /// <value>The pending count.</value>
         public int PendingTransferCount { get; private set; }
 
+        TWImageInfo _imgInfo;
         /// <summary>
         /// Gets the tentative image information for the current transfer if applicable.
         /// This may differ from the final image depending on the transfer mode used (mostly when doing mem xfer).
@@ -56,15 +63,42 @@ namespace NTwain
         /// <value>
         /// The image info.
         /// </value>
-        public TWImageInfo PendingImageInfo { get; private set; }
+        public TWImageInfo PendingImageInfo
+        {
+            get
+            {
+                if (_imgInfo == null)
+                {
+                    if (DataSource.DGImage.ImageInfo.Get(out _imgInfo) != ReturnCode.Success)
+                    {
+                        _imgInfo = null;
+                    }
+                }
+                return _imgInfo;
+            }
+        }
 
+        TWAudioInfo _audInfo;
         /// <summary>
         /// Gets the audio information for the current transfer if applicable.
         /// </summary>
         /// <value>
         /// The audio information.
         /// </value>
-        public TWAudioInfo AudioInfo { get; private set; }
+        public TWAudioInfo AudioInfo
+        {
+            get
+            {
+                if (_audInfo == null)
+                {
+                    if (DataSource.DGAudio.AudioInfo.Get(out _audInfo) != ReturnCode.Success)
+                    {
+                        _audInfo = null;
+                    }
+                }
+                return _audInfo;
+            }
+        }
 
     }
 }