private async Task <ReadFileResult> ReadFile(int length)
{
IBuffer content = bufferAllocator.Allocate(length);
Stream dest = content.GetStream();
IMD5HashProvider chunkHash = MD5HashProviderFactory.GetHashProvider().CreateHash();
byte[] b = ArrayPool <byte> .Shared.Rent(Configuration.BufferSize);
try
{
int read = 0;
int toRead = length;
do
{
read = await fileStream.ReadAsync(b, offset : 0, count : Math.Min(b.Length, toRead)).ConfigureAwait(false);
toRead -= read;
await dest.WriteAsync(b, offset : 0, count : read).ConfigureAwait(false);
chunkHash.Append(b, offset: 0, size: read);
fileHash.Append(b, offset: 0, size: read);
} while (read > 0 && toRead > 0);
if (toRead > 0)
{
throw new Exception($"Expected to read {length} bytes, actual read {length - toRead} bytes");
}
chunkHash.Finalize(ArrayPool <byte> .Shared.Rent(0), 0, 0);
return(new ReadFileResult {
Content = content, Hash = chunkHash.GetComputedHashAsString()
});
}
catch
{
content.Dispose();
throw;
}
finally
{
ArrayPool <byte> .Shared.Return(b);
dest.Dispose();
}
}