protected StorageWriteStream(
long position,
long bufferSize,
IProgress <long> progressHandler,
PooledMemoryStream buffer = null)
{
_position = position;
_bufferSize = bufferSize;
if (progressHandler != null)
{
_progressHandler = new AggregatingProgressIncrementer(progressHandler);
}
if (buffer != null)
{
_buffer = buffer;
_shouldDisposeBuffer = false;
}
else
{
_buffer = new PooledMemoryStream(
arrayPool: ArrayPool <byte> .Shared,
absolutePosition: 0,
maxArraySize: (int)Math.Min(Constants.MB, bufferSize));
_shouldDisposeBuffer = true;
}
}
protected StorageWriteStream(
long position,
long bufferSize,
IProgress <long> progressHandler,
// TODO #27253
//UploadTransactionalHashingOptions hashingOptions,
PooledMemoryStream buffer = null)
{
_position = position;
_bufferSize = bufferSize;
if (progressHandler != null)
{
_progressHandler = new AggregatingProgressIncrementer(progressHandler);
}
// TODO #27253
//_hashingOptions = hashingOptions;
// write streams don't support pre-calculated hashes
//if (_hashingOptions?.PrecalculatedHash != default)
//{
// throw Errors.PrecalculatedHashNotSupportedOnSplit();
//}
if (buffer != null)
{
_buffer = buffer;
_shouldDisposeBuffer = false;
}
else
{
_buffer = new PooledMemoryStream(
arrayPool: ArrayPool <byte> .Shared,
absolutePosition: 0,
maxArraySize: (int)Math.Min(Constants.MB, bufferSize));
_shouldDisposeBuffer = true;
}
}
/// <summary>
/// Buffers a portion of the given stream, returning the buffered stream partition.
/// </summary>
/// <param name="stream">
/// Stream to buffer from.
/// </param>
/// <param name="minCount">
/// Minimum number of bytes to buffer. This method will not return until at least this many bytes have been read from <paramref name="stream"/> or the stream completes.
/// </param>
/// <param name="maxCount">
/// Maximum number of bytes to buffer.
/// </param>
/// <param name="absolutePosition">
/// Current position of the stream, since <see cref="Stream.Position"/> throws if not seekable.
/// </param>
/// <param name="arrayPool">
/// Pool to rent buffer space from.
/// </param>
/// <param name="maxArrayPoolRentalSize">
/// Max size we can request from the array pool.
/// </param>
/// <param name="async">
/// Whether to perform this operation asynchronously.
/// </param>
/// <param name="cancellationToken">
/// Cancellation token.
/// </param>
/// <returns>
/// The buffered stream partition with memory backed by an array pool.
/// </returns>
internal static async Task <PooledMemoryStream> BufferStreamPartitionInternal(
Stream stream,
long minCount,
long maxCount,
long absolutePosition,
ArrayPool <byte> arrayPool,
int?maxArrayPoolRentalSize,
bool async,
CancellationToken cancellationToken)
{
long totalRead = 0;
var streamPartition = new PooledMemoryStream(arrayPool, absolutePosition, maxArrayPoolRentalSize ?? DefaultMaxArrayPoolRentalSize);
// max count to write into a single array
int maxCountIndividualBuffer;
// min count to write into a single array
int minCountIndividualBuffer;
// the amount that was written into the current array
int readIndividualBuffer;
do
{
// buffer to write to
byte[] buffer;
// offset to start writing at
int offset;
BufferPartition latestBuffer = streamPartition.GetLatestBufferWithAvailableSpaceOrDefault();
// whether we got a brand new buffer to write into
bool newbuffer;
if (latestBuffer != default)
{
buffer = latestBuffer.Buffer;
offset = latestBuffer.DataLength;
newbuffer = false;
}
else
{
buffer = arrayPool.Rent((int)Math.Min(maxCount - totalRead, streamPartition.MaxArraySize));
offset = 0;
newbuffer = true;
}
// limit max and min count for this buffer by buffer length
maxCountIndividualBuffer = (int)Math.Min(maxCount - totalRead, buffer.Length - offset);
// definitionally limited by max; we won't ever have a swapped min/max range
minCountIndividualBuffer = (int)Math.Min(minCount - totalRead, maxCountIndividualBuffer);
readIndividualBuffer = await ReadLoopInternal(
stream,
buffer,
offset : offset,
minCountIndividualBuffer,
maxCountIndividualBuffer,
async,
cancellationToken).ConfigureAwait(false);
// if nothing was placed in a brand new array
if (readIndividualBuffer == 0 && newbuffer)
{
arrayPool.Return(buffer);
}
// if brand new array and we did place data in it
else if (newbuffer)
{
streamPartition.BufferSet.Add(new BufferPartition
{
Buffer = buffer,
DataLength = readIndividualBuffer
});
}
// added to an existing array that was not entirely filled
else
{
latestBuffer.DataLength += readIndividualBuffer;
}
totalRead += readIndividualBuffer;
/* If we filled the buffer this loop, then quitting on min count is pointless. The point of quitting
* on min count is when the source stream doesn't have available bytes and we've reached an amount worth
* sending instead of blocking on. If we filled the available array, we don't actually know whether more
* data is available yet, as we limited our read for reasons outside the stream state. We should therefore
* try another read regardless of whether we hit min count.
*/
} while (
// stream is done if this value is zero; no other check matters
readIndividualBuffer != 0 &&
// stop filling the partition if we've hit the max size of the partition
totalRead < maxCount &&
// stop filling the partition if we've reached min count and we know we've hit at least a pause in the stream
(totalRead < minCount || readIndividualBuffer == maxCountIndividualBuffer));
return(streamPartition);
}