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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <cstddef>
#include <map>
#include <string>
#include "net/third_party/quiche/src/quic/core/quic_packets.h"
#include "net/third_party/quiche/src/quic/core/quic_stream_sequencer_buffer.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_export.h"
namespace quic {
namespace test {
class QuicStreamSequencerPeer;
} // namespace test
// Buffers frames until we have something which can be passed
// up to the next layer.
class QUIC_EXPORT_PRIVATE QuicStreamSequencer {
// Interface that thie Sequencer uses to communicate with the Stream.
class StreamInterface {
virtual ~StreamInterface() = default;
// Called when new data is available to be read from the sequencer.
virtual void OnDataAvailable() = 0;
// Called when the end of the stream has been read.
virtual void OnFinRead() = 0;
// Called when bytes have been consumed from the sequencer.
virtual void AddBytesConsumed(QuicByteCount bytes) = 0;
// TODO(rch): Clean up this interface via OnUnrecoverableError and
// remove PeerAddressOfLatestPacket().
// Called when an error has occurred which should result in the stream
// being reset.
virtual void Reset(QuicRstStreamErrorCode error) = 0;
// Called when an error has occurred which should result in the connection
// being closed.
virtual void CloseConnectionWithDetails(QuicErrorCode error,
const std::string& details) = 0;
// Returns the stream id of this stream.
virtual QuicStreamId id() const = 0;
// Returns the peer address of the last packet received for this stream.
virtual const QuicSocketAddress& PeerAddressOfLatestPacket() const = 0;
explicit QuicStreamSequencer(StreamInterface* quic_stream);
QuicStreamSequencer(const QuicStreamSequencer&) = delete;
QuicStreamSequencer(QuicStreamSequencer&&) = default;
QuicStreamSequencer& operator=(const QuicStreamSequencer&) = delete;
virtual ~QuicStreamSequencer();
// If the frame is the next one we need in order to process in-order data,
// ProcessData will be immediately called on the stream until all buffered
// data is processed or the stream fails to consume data. Any unconsumed
// data will be buffered. If the frame is not the next in line, it will be
// buffered.
void OnStreamFrame(const QuicStreamFrame& frame);
// If the frame is the next one we need in order to process in-order data,
// ProcessData will be immediately called on the crypto stream until all
// buffered data is processed or the crypto stream fails to consume data. Any
// unconsumed data will be buffered. If the frame is not the next in line, it
// will be buffered.
void OnCryptoFrame(const QuicCryptoFrame& frame);
// Once data is buffered, it's up to the stream to read it when the stream
// can handle more data. The following three functions make that possible.
// Fills in up to iov_len iovecs with the next readable regions. Returns the
// number of iovs used. Non-destructive of the underlying data.
int GetReadableRegions(iovec* iov, size_t iov_len) const;
// Fills in one iovec with the next readable region. Returns false if there
// is no readable region available.
bool GetReadableRegion(iovec* iov) const;
// Fills in one iovec with the region starting at |offset| and returns true.
// Returns false if no readable region is available, either because data has
// not been received yet or has already been consumed.
bool PeekRegion(QuicStreamOffset offset, iovec* iov) const;
// Fills in one iovec with the next unread region.
// Returns false if no readable region is available.
bool PrefetchNextRegion(iovec* iov);
// Copies the data into the iov_len buffers provided. Returns the number of
// bytes read. Any buffered data no longer in use will be released.
// TODO(rch): remove this method and instead implement it as a helper method
// based on GetReadableRegions and MarkConsumed.
int Readv(const struct iovec* iov, size_t iov_len);
// Consumes |num_bytes| data. Used in conjunction with |GetReadableRegions|
// to do zero-copy reads.
void MarkConsumed(size_t num_bytes);
// Appends all of the readable data to |buffer| and marks all of the appended
// data as consumed.
void Read(std::string* buffer);
// Returns true if the sequncer has bytes available for reading.
bool HasBytesToRead() const;
// Number of bytes available to read.
size_t ReadableBytes() const;
// Returns true if the sequencer has delivered the fin.
bool IsClosed() const;
// Calls |OnDataAvailable| on |stream_| if there is buffered data that can
// be processed, and causes |OnDataAvailable| to be called as new data
// arrives.
void SetUnblocked();
// Blocks processing of frames until |SetUnblocked| is called.
void SetBlockedUntilFlush();
// Sets the sequencer to discard all incoming data itself and not call
// |stream_->OnDataAvailable()|. |stream_->OnFinRead()| will be called
// automatically when the FIN is consumed (which may be immediately).
void StopReading();
// Free the memory of underlying buffer.
void ReleaseBuffer();
// Free the memory of underlying buffer when no bytes remain in it.
void ReleaseBufferIfEmpty();
// Number of bytes in the buffer right now.
size_t NumBytesBuffered() const;
// Number of bytes has been consumed.
QuicStreamOffset NumBytesConsumed() const;
QuicStreamOffset close_offset() const { return close_offset_; }
int num_frames_received() const { return num_frames_received_; }
int num_duplicate_frames_received() const {
return num_duplicate_frames_received_;
bool ignore_read_data() const { return ignore_read_data_; }
void set_level_triggered(bool level_triggered) {
level_triggered_ = level_triggered;
bool level_triggered() const { return level_triggered_; }
void set_stream(StreamInterface* stream) { stream_ = stream; }
// Returns string describing internal state.
const std::string DebugString() const;
friend class test::QuicStreamSequencerPeer;
// Deletes and records as consumed any buffered data that is now in-sequence.
// (To be called only after StopReading has been called.)
void FlushBufferedFrames();
// Wait until we've seen 'offset' bytes, and then terminate the stream.
void CloseStreamAtOffset(QuicStreamOffset offset);
// If we've received a FIN and have processed all remaining data, then inform
// the stream of FIN, and clear buffers.
bool MaybeCloseStream();
// Shared implementation between OnStreamFrame and OnCryptoFrame.
void OnFrameData(QuicStreamOffset byte_offset,
size_t data_len,
const char* data_buffer);
// The stream which owns this sequencer.
StreamInterface* stream_;
// Stores received data in offset order.
QuicStreamSequencerBuffer buffered_frames_;
// The offset, if any, we got a stream termination for. When this many bytes
// have been processed, the sequencer will be closed.
QuicStreamOffset close_offset_;
// If true, the sequencer is blocked from passing data to the stream and will
// buffer all new incoming data until FlushBufferedFrames is called.
bool blocked_;
// Count of the number of frames received.
int num_frames_received_;
// Count of the number of duplicate frames received.
int num_duplicate_frames_received_;
// If true, all incoming data will be discarded.
bool ignore_read_data_;
// If false, only call OnDataAvailable() when it becomes newly unblocked.
// Otherwise, call OnDataAvailable() when number of readable bytes changes.
bool level_triggered_;
// Latched value of quic_stop_reading_when_level_triggered flag. When true,
// the sequencer will discard incoming data (but not FIN bits) after
// StopReading is called, even in level_triggered_ mode.
const bool stop_reading_when_level_triggered_;
} // namespace quic