/// <summary>
/// Internal helper method to wrap a user provided stream with the appropriate crypto stream.
/// </summary>
internal static Stream WrapUserStreamWithDecryptStream(CloudBlob blob, Stream userProvidedStream, BlobRequestOptions options, BlobAttributes attributes, bool rangeRead, out ICryptoTransform transform, long?endOffset = null, long?userSpecifiedLength = null, int discardFirst = 0, bool bufferIV = false)
{
if (!rangeRead)
{
// The user provided stream should be wrapped in a NonCloseableStream in order to
// avoid closing the user stream when the crypto stream is closed to flush the final decrypted
// block of data.
Stream decryptStream = options.EncryptionPolicy.DecryptBlob(new NonCloseableStream(userProvidedStream), attributes.Metadata, out transform, options.RequireEncryption, null, blob.BlobType == BlobType.PageBlob);
return(decryptStream);
}
else
{
// Check if end offset lies in the last AES block and send this information over to set the correct padding mode.
bool noPadding = blob.BlobType == BlobType.PageBlob || (endOffset.HasValue && endOffset.Value < attributes.Properties.Length - 16);
transform = null;
return(new BlobDecryptStream(userProvidedStream, attributes.Metadata, userSpecifiedLength, discardFirst, bufferIV, noPadding, options.EncryptionPolicy, options.RequireEncryption));
}
}
/// <summary>
/// Initializes a new instance of the <see cref="CloudBlockBlob"/> class.
/// </summary>
/// <param name="attributes">The attributes.</param>
/// <param name="serviceClient">The service client.</param>
internal CloudBlockBlob(BlobAttributes attributes, CloudBlobClient serviceClient)
: base(attributes, serviceClient)
{
this.Properties.BlobType = BlobType.BlockBlob;
}