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) = 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_