private static void DecompressAttachment(IEnumerable <PartInfo> payloadInfo, Attachment attachment)
{
PartInfo referenced = payloadInfo.FirstOrDefault(attachment.Matches);
if (referenced == null)
{
throw new InvalidDataException(
$"Can't decompress Attachment {attachment.Id} because no matching PartInfo was found");
}
if (String.IsNullOrWhiteSpace(referenced.MimeType))
{
throw new InvalidDataException(
$"Cannot decompress attachment {attachment.Id}: MimeType is not specified in referenced <PartInfo/> element");
}
if (referenced.MimeType.IndexOf("/", StringComparison.OrdinalIgnoreCase) < 0)
{
throw new InvalidDataException(
$"Cannot decompress attachment {attachment.Id}: Invalid MimeType {referenced.MimeType} in referenced <PartInfo/> element");
}
attachment.ResetContentPosition();
long unzipLength = StreamUtilities.DetermineOriginalSizeOfCompressedStream(attachment.Content);
VirtualStream outputStream =
VirtualStream.Create(
unzipLength > -1 ? unzipLength : VirtualStream.ThresholdMax);
if (unzipLength > 0)
{
outputStream.SetLength(unzipLength);
}
Stream decompressed = DecompressStream(attachment.Content);
referenced.CompressionType = CompressionType;
attachment.CompressionType = CompressionType;
attachment.MimeType = referenced.MimeType;
attachment.UpdateContent(decompressed, referenced.MimeType);
}
private static Stream DecompressStream(Stream input)
{
long unzipLength = StreamUtilities.DetermineOriginalSizeOfCompressedStream(input);
VirtualStream outputStream =
VirtualStream.Create(
unzipLength > -1 ? unzipLength : VirtualStream.ThresholdMax);
if (unzipLength > 0)
{
outputStream.SetLength(unzipLength);
}
using (var gzipCompression = new GZipStream(input, CompressionMode.Decompress, true))
{
gzipCompression.CopyTo(outputStream);
outputStream.Position = 0;
return(outputStream);
}
}