net/quic/quic_ack_notifier.h

   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
  11 namespace 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.
  18 class 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,
  34                                    QuicTime::Delta delta_largest_observed) = 0;
  35    protected:
  36     friend class base::RefCounted<DelegateInterface>;
  37
  38     // Delegates are ref counted.
  39     virtual ~DelegateInterface();
  40   };
  41
  42   // QuicAckNotifier is expected to keep its own reference to the delegate.
  43   explicit QuicAckNotifier(DelegateInterface* delegate);
  44   virtual ~QuicAckNotifier();
  45
  46   // Register a sequence number that this AckNotifier should be interested in.
  47   void AddSequenceNumber(const QuicPacketSequenceNumber& sequence_number,
  48                          int packet_payload_size);
  49
  50   // Called by the QuicConnection on receipt of new ACK frame, with the sequence
  51   // number referenced by the ACK frame.
  52   // Deletes the matching sequence number from the stored set of sequence
  53   // numbers. If this set is now empty, call the stored delegate's
  54   // OnAckNotification method.
  55   //
  56   // Returns true if the provided sequence_number caused the delegate to be
  57   // called, false otherwise.
  58   bool OnAck(QuicPacketSequenceNumber sequence_number,
  59              QuicTime::Delta delta_largest_observed);
  60
  61   bool IsEmpty() { return sequence_numbers_.empty(); }
  62
  63   // If a packet is retransmitted by the connection it will be sent with a
  64   // different sequence number. Updates our internal set of sequence_numbers to
  65   // track the latest number.
  66   void UpdateSequenceNumber(QuicPacketSequenceNumber old_sequence_number,
  67                             QuicPacketSequenceNumber new_sequence_number);
  68
  69  private:
  70   struct PacketInfo {
  71     PacketInfo();
  72     explicit PacketInfo(int payload_size);
  73
  74     int packet_payload_size;
  75   };
  76
  77   // The delegate's OnAckNotification() method will be called once we have been
  78   // notified of ACKs for all the sequence numbers we are tracking.
  79   // This is not owned by OnAckNotifier and must outlive it.
  80   scoped_refptr<DelegateInterface> delegate_;
  81
  82   // Sequence numbers this notifier is waiting to hear about. The
  83   // delegate will not be called until this is empty.
  84   base::hash_map<QuicPacketSequenceNumber, PacketInfo> sequence_numbers_;
  85
  86   // Transmission and retransmission stats.
  87   // Number of packets in the original transmission.
  88   int original_packet_count_;
  89   // Number of packets in the original transmission.
  90   int original_byte_count_;
  91   // Number of packets that had to be retransmitted.
  92   int retransmitted_packet_count_;
  93   // Number of bytes that had to be retransmitted.
  94   int retransmitted_byte_count_;
  95
  96   DISALLOW_COPY_AND_ASSIGN(QuicAckNotifier);
  97 };
  98
  99 };  // namespace net
 100
 101 #endif  // NET_QUIC_QUIC_ACK_NOTIFIER_H_