Behavior change regarding seekability of streams returned for ZipArchive

[ojhad]

• .NET Core Version: 3.0.100-preview4

Problem description:

There is a behavior change regarding the seekability of returned ZipArchiveEntry streams.

.NET Framework behavior:

The WindowsBase implementation of Zip had the necessary functionality that operated on the returned deflate streams which provided support for seeking (However, in doing so, it incurred a lot of extra CPU and file system usage)

.NET Core behavior:
The current implementation in CoreFX (System.IO.Packaging) no longer provides this functionality, resulting in streams that are being returned to be non-seekable.

Related Issue:
https://github.com/dotnet/corefx/issues/34219

[jbartlau]

I'm also having an issue with this exception if I call

var document = new XpsDocument(@"repro.xps", FileAccess.Read);
var paginatorSource = (IDocumentPaginatorSource)document.GetFixedDocumentSequence();

on the attached XPS file (which was created with the XPS Document Writer driver). See my comment at #575. Exception details:

System.NotSupportedException
  HResult=0x80131515
  Message=This operation is not supported.
  Source=System.IO.Compression
  StackTrace:
   at System.IO.Compression.DeflateStream.get_Position()
   at System.IO.Packaging.ZipWrappingStream.get_Position()
   at MS.Internal.IO.Packaging.SynchronizingStream.get_Position() in /_/src/Microsoft.DotNet.Wpf/src/shared/MS/Internal/IO/SynchronizingStream.cs:line 207
   at MS.Internal.IO.Packaging.DeobfuscatingStream.Read(Byte[] buffer, Int32 offset, Int32 count) in /_/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/Internal/IO/Packaging/DeobfuscatingStream.cs:line 56
   at MS.Internal.FontCache.FontSource.StreamToByteArray(Stream fontStream) in /_/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/Internal/FontCache/FontSource.cs:line 419
   at MS.Internal.FontCache.FontSource.GetUnmanagedStream() in /_/src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/Internal/FontCache/FontSource.cs:line 279
   at MS.Internal.Text.TextInterface.FontFileStream..ctor(IFontSource fontSource)
   at MS.Internal.Text.TextInterface.FontFileLoader.CreateStreamFromKey(Void* fontFileReferenceKey, UInt32 fontFileReferenceKeySize, IntPtr* fontFileStream)

repro.zip

[vatsan-madhavan]

@grubioe - we need to document this issue as a change, and remove this from our queue. likely this is not going to actionable.