quic_ack_notifier.h revision a1401311d1ab56c4ed0a474bd38c108f75cb0cd9 
1// Copyright 2013 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.
4
5#ifndef NET_QUIC_QUIC_ACK_NOTIFIER_H_
6#define NET_QUIC_QUIC_ACK_NOTIFIER_H_
7
8#include "base/memory/ref_counted.h"
9#include "net/quic/quic_protocol.h"
10
11namespace net {
12
13// Used to register with a QuicConnection for notification once a set of packets
14// have all been ACKed.
15// The connection informs this class of newly ACKed sequence numbers, and once
16// we have seen ACKs for all the sequence numbers we are interested in, we
17// trigger a call to a provided Closure.
18class NET_EXPORT_PRIVATE QuicAckNotifier {
19 public:
20 class NET_EXPORT_PRIVATE DelegateInterface
21     : public base::RefCounted<DelegateInterface> {
22   public:
23    DelegateInterface();
24    // Args:
25    //  num_original_packets - Number of packets in the original transmission.
26    //  num_original_bytes - Number of packets in the original transmission.
27    //  num_retransmitted_packets - Number of packets that had to be
28    //                              retransmitted.
29    //  num_retransmitted_bytes - Number of bytes that had to be retransmitted.
30    virtual void OnAckNotification(int num_original_packets,
31                                   int num_original_bytes,
32                                   int num_retransmitted_packets,
33                                   int num_retransmitted_bytes) = 0;
34   protected:
35    friend class base::RefCounted<DelegateInterface>;
36
37    // Delegates are ref counted.
38    virtual ~DelegateInterface();
39  };
40
41  // QuicAckNotifier is expected to keep its own reference to the delegate.
42  explicit QuicAckNotifier(DelegateInterface* delegate);
43  virtual ~QuicAckNotifier();
44
45  // Register a sequence number that this AckNotifier should be interested in.
46  void AddSequenceNumber(const QuicPacketSequenceNumber& sequence_number,
47                         int packet_payload_size);
48
49  // Called by the QuicConnection on receipt of new ACK frame, with the sequence
50  // number referenced by the ACK frame.
51  // Deletes the matching sequence number from the stored set of sequence
52  // numbers. If this set is now empty, call the stored delegate's
53  // OnAckNotification method.
54  //
55  // Returns true if the provided sequence_number caused the delegate to be
56  // called, false otherwise.
57  bool OnAck(QuicPacketSequenceNumber sequence_number);
58
59  bool IsEmpty() { return sequence_numbers_.empty(); }
60
61  // If a packet is retransmitted by the connection it will be sent with a
62  // different sequence number. Updates our internal set of sequence_numbers to
63  // track the latest number.
64  void UpdateSequenceNumber(QuicPacketSequenceNumber old_sequence_number,
65                            QuicPacketSequenceNumber new_sequence_number);
66
67 private:
68  struct PacketInfo {
69    PacketInfo();
70    explicit PacketInfo(int payload_size);
71
72    int packet_payload_size;
73  };
74
75  // The delegate's OnAckNotification() method will be called once we have been
76  // notified of ACKs for all the sequence numbers we are tracking.
77  // This is not owned by OnAckNotifier and must outlive it.
78  scoped_refptr<DelegateInterface> delegate_;
79
80  // Sequence numbers this notifier is waiting to hear about. The
81  // delegate will not be called until this is empty.
82  base::hash_map<QuicPacketSequenceNumber, PacketInfo> sequence_numbers_;
83
84  // Transmission and retransmission stats.
85  // Number of packets in the original transmission.
86  int original_packet_count_;
87  // Number of packets in the original transmission.
88  int original_byte_count_;
89  // Number of packets that had to be retransmitted.
90  int retransmitted_packet_count_;
91  // Number of bytes that had to be retransmitted.
92  int retransmitted_byte_count_;
93};
94
95};  // namespace net
96
97#endif  // NET_QUIC_QUIC_ACK_NOTIFIER_H_
98