1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef NET_QUIC_QUIC_STREAM_SEQUENCER_H_
6 #define NET_QUIC_QUIC_STREAM_SEQUENCER_H_
10 #include "base/basictypes.h"
11 #include "net/base/iovec.h"
12 #include "net/quic/quic_protocol.h"
20 class QuicStreamSequencerPeer;
24 class ReliableQuicStream;
26 // Buffers frames until we have something which can be passed
27 // up to the next layer.
28 // TOOD(alyssar) add some checks for overflow attempts [1, 256,] [2, 256]
29 class NET_EXPORT_PRIVATE QuicStreamSequencer {
31 explicit QuicStreamSequencer(ReliableQuicStream* quic_stream);
32 QuicStreamSequencer(size_t max_frame_memory,
33 ReliableQuicStream* quic_stream);
35 virtual ~QuicStreamSequencer();
37 // Returns the expected value of OnStreamFrame for this frame.
38 bool WillAcceptStreamFrame(const QuicStreamFrame& frame) const;
40 // If the frame is the next one we need in order to process in-order data,
41 // ProcessData will be immediately called on the stream until all buffered
42 // data is processed or the stream fails to consume data. Any unconsumed
43 // data will be buffered.
45 // If the frame is not the next in line, it will either be buffered, and
46 // this will return true, or it will be rejected and this will return false.
47 bool OnStreamFrame(const QuicStreamFrame& frame);
49 // Once data is buffered, it's up to the stream to read it when the stream
50 // can handle more data. The following three functions make that possible.
52 // Fills in up to iov_len iovecs with the next readable regions. Returns the
53 // number of iovs used. Non-destructive of the underlying data.
54 int GetReadableRegions(iovec* iov, size_t iov_len);
56 // Copies the data into the iov_len buffers provided. Returns the number of
57 // bytes read. Any buffered data no longer in use will be released.
58 int Readv(const struct iovec* iov, size_t iov_len);
60 // Consumes |num_bytes| data. Used in conjunction with |GetReadableRegions|
61 // to do zero-copy reads.
62 void MarkConsumed(size_t num_bytes);
64 // Returns true if the sequncer has bytes available for reading.
65 bool HasBytesToRead() const;
67 // Returns true if the sequencer has delivered the fin.
68 bool IsClosed() const;
70 // Returns true if the sequencer has received this frame before.
71 bool IsDuplicate(const QuicStreamFrame& frame) const;
73 // Calls |ProcessRawData| on |stream_| for each buffered frame that may
75 void FlushBufferedFrames();
77 // Blocks processing of frames until |FlushBufferedFrames| is called.
78 void SetBlockedUntilFlush();
80 size_t num_bytes_buffered() const {
81 return num_bytes_buffered_;
85 friend class test::QuicStreamSequencerPeer;
87 // Wait until we've seen 'offset' bytes, and then terminate the stream.
88 void CloseStreamAtOffset(QuicStreamOffset offset);
90 // If we've received a FIN and have processed all remaining data, then inform
91 // the stream of FIN, and clear buffers.
92 bool MaybeCloseStream();
94 // Called whenever bytes are consumed by the stream. Updates
95 // num_bytes_consumed_ and num_bytes_buffered_.
96 void RecordBytesConsumed(size_t bytes_consumed);
98 // The stream which owns this sequencer.
99 ReliableQuicStream* stream_;
101 // The last data consumed by the stream.
102 QuicStreamOffset num_bytes_consumed_;
104 // TODO(alyssar) use something better than strings.
105 typedef map<QuicStreamOffset, string> FrameMap;
107 // Stores buffered frames (maps from sequence number -> frame data as string).
110 // The maximum memory the sequencer can buffer.
111 size_t max_frame_memory_;
113 // The offset, if any, we got a stream termination for. When this many bytes
114 // have been processed, the sequencer will be closed.
115 QuicStreamOffset close_offset_;
117 // If true, the sequencer is blocked from passing data to the stream and will
118 // buffer all new incoming data until FlushBufferedFrames is called.
121 // Tracks how many bytes the sequencer has buffered.
122 size_t num_bytes_buffered_;
127 #endif // NET_QUIC_QUIC_STREAM_SEQUENCER_H_