private void CreateLocalCopyFromHttpSource(
NativeInterfaces.IShellItem item,
IFileTransferProgressEvents progressEvents,
out string pathNameResult)
{
string url = null;
item.GetDisplayName(NativeConstants.SIGDN.SIGDN_URL, out url);
Uri uri = new Uri(url);
string pathName = FileSystem.GetTempPathName(url);
WebRequest webRequest = WebRequest.Create(uri);
webRequest.Timeout = 5000;
using (WebResponse webResponse = webRequest.GetResponse())
{
VerifyNotCanceled();
using (Stream uriStream = webResponse.GetResponseStream())
{
VerifyNotCanceled();
using (FileStream outStream = new FileStream(pathName, FileMode.Create, FileAccess.Write, FileShare.Read))
{
VerifyNotCanceled();
const int bufSize = 512;
long length = webResponse.ContentLength;
long bytesLeft = length;
byte[] buffer = new byte[bufSize];
progressEvents.SetItemWorkTotal(length);
while (bytesLeft > 0)
{
int amtRead = uriStream.Read(buffer, 0, buffer.Length);
VerifyNotCanceled();
outStream.Write(buffer, 0, amtRead);
VerifyNotCanceled();
bytesLeft -= amtRead;
progressEvents.SetItemWorkProgress(length - bytesLeft);
VerifyNotCanceled();
}
}
}
}
pathNameResult = pathName;
}
private unsafe void CreateLocalCopyFromIStreamSource(
NativeInterfaces.IShellItem item,
IFileTransferProgressEvents progressEvents,
out string pathNameResult)
{
string fileName = null;
item.GetDisplayName(NativeConstants.SIGDN.SIGDN_NORMALDISPLAY, out fileName);
string pathName = FileSystem.GetTempPathName(fileName);
Guid bhidStream = NativeConstants.BHID_Stream;
Guid iid_IStream = new Guid(NativeConstants.IID_IStream);
NativeInterfaces.IStream iStream = null;
item.BindToHandler(IntPtr.Zero, ref bhidStream, ref iid_IStream, out iStream);
try
{
VerifyNotCanceled();
NativeStructs.STATSTG statstg = new NativeStructs.STATSTG();
iStream.Stat(out statstg, NativeConstants.STATFLAG.STATFLAG_NONAME);
progressEvents.SetItemWorkTotal((long)statstg.cbSize);
const int bufSize = 4096;
byte[] buffer = new byte[bufSize];
fixed (void* pbBuffer = buffer)
{
IntPtr pbBuffer2 = new IntPtr(pbBuffer);
ulong qwBytesLeft = statstg.cbSize;
using (FileStream localFile = new FileStream(pathName, FileMode.Create, FileAccess.Write, FileShare.Read))
{
VerifyNotCanceled();
// NOTE: We do not call VerifyNotCanceled() during any individual item. This is because, while testing
// this, it was determined that oftentimes the transfer gets very confused if we just stop
// calling Read() and jump straight to Marshal.ReleaseComObject(). By "confused" I mean that
// the "Canceling..." text would remain on the progress dialog for up to a minute, and then
// the blinking light on the camera would continue indefinitely and you wouldn't be able to
// use the camera again until you unplugged it and plugged it back in.
while (qwBytesLeft > 0)
{
uint wantToRead = (uint)Math.Min(qwBytesLeft, bufSize);
uint amtRead = 0;
iStream.Read(pbBuffer2, wantToRead, out amtRead);
if (amtRead > qwBytesLeft)
{
throw new InvalidOperationException("IStream::Read() reported that more bytes were read than were in the file");
}
qwBytesLeft -= amtRead;
localFile.Write(buffer, 0, (int)amtRead);
progressEvents.SetItemWorkProgress((long)(statstg.cbSize - qwBytesLeft));
}
}
VerifyNotCanceled();
}
}
finally
{
if (iStream != null)
{
try
{
Marshal.ReleaseComObject(iStream);
}
catch (Exception)
{
}
iStream = null;
}
}
pathNameResult = pathName;
}
// Returns true if the item copied successfully, false if it didn't (error or skipped)
private CopyResult CreateLocalCopy(
NativeInterfaces.IShellItem item,
IFileTransferProgressEvents progressEvents,
out string pathNameResult)
{
CopyResult returnResult;
WorkItemResult itemResult;
string displayName = null;
item.GetDisplayName(NativeConstants.SIGDN.SIGDN_NORMALDISPLAY, out displayName);
progressEvents.SetItemInfo(displayName);
progressEvents.BeginItem();
while (true)
{
// Determine whether to copy from HTTP or from IStream. The heuristic we use here is simple:
// if the attributes has SFGAO_CANCOPY, we IStream it. Else, we HTTP it.
NativeConstants.SFGAO attribs;
item.GetAttributes((NativeConstants.SFGAO)0xfffffff, out attribs);
try
{
if ((attribs & NativeConstants.SFGAO.SFGAO_CANCOPY) == NativeConstants.SFGAO.SFGAO_CANCOPY)
{
CreateLocalCopyFromIStreamSource(item, progressEvents, out pathNameResult);
}
else
{
CreateLocalCopyFromHttpSource(item, progressEvents, out pathNameResult);
}
returnResult = CopyResult.Success;
itemResult = WorkItemResult.Finished;
break;
}
catch (OperationCanceledException)
{
returnResult = CopyResult.CancelOperation;
itemResult = WorkItemResult.Skipped;
pathNameResult = null;
break;
}
catch (Exception ex)
{
WorkItemFailureAction choice = progressEvents.ReportItemFailure(ex);
if (choice == WorkItemFailureAction.SkipItem)
{
pathNameResult = null;
returnResult = CopyResult.Skipped;
itemResult = WorkItemResult.Skipped;
break;
}
else if (choice == WorkItemFailureAction.RetryItem)
{
continue;
}
else if (choice == WorkItemFailureAction.CancelOperation)
{
pathNameResult = null;
returnResult = CopyResult.CancelOperation;
itemResult = WorkItemResult.Skipped;
break;
}
}
}
progressEvents.EndItem(itemResult);
return returnResult;
}