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_retransmitted_packets - Number of packets that had to be
  26     //                              retransmitted.
  27     //  num_retransmitted_bytes - Number of bytes that had to be retransmitted.
  28     virtual void OnAckNotification(int num_retransmitted_packets,
  29                                    int num_retransmitted_bytes,
  30                                    QuicTime::Delta delta_largest_observed) = 0;
  31
  32    protected:
  33     friend class base::RefCounted<DelegateInterface>;
  34
  35     // Delegates are ref counted.
  36     virtual ~DelegateInterface();
  37   };
  38
  39   // QuicAckNotifier is expected to keep its own reference to the delegate.
  40   explicit QuicAckNotifier(DelegateInterface* delegate);
  41   virtual ~QuicAckNotifier();
  42
  43   // Register a serialized packet the notifier should track.
  44   void OnSerializedPacket();
  45
  46   // Called on receipt of new ACK frame for an unacked packet.
  47   // Decrements the number of unacked packets and if there are none left, calls
  48   // the stored delegate's OnAckNotification method.
  49   //
  50   // Returns true if the delegate was called, false otherwise.
  51   bool OnAck(QuicTime::Delta delta_largest_observed);
  52
  53   // Called when we've given up waiting for a sequence number, typically when
  54   // the connection is torn down.
  55   // Returns true if there are no more unacked packets being tracked.
  56   bool OnPacketAbandoned();
  57
  58   bool HasUnackedPackets() const { return unacked_packets_ > 0; }
  59
  60   // If a packet is retransmitted by the connection, it will be sent with a
  61   // different sequence number.
  62   void OnPacketRetransmitted(int packet_payload_size);
  63
  64  private:
  65   // The delegate's OnAckNotification() method will be called once we have been
  66   // notified of ACKs for all the sequence numbers we are tracking.
  67   // This is not owned by OnAckNotifier and must outlive it.
  68   scoped_refptr<DelegateInterface> delegate_;
  69
  70   // The number of unacked packets being tracked.
  71   int unacked_packets_;
  72
  73   // Number of packets that had to be retransmitted.
  74   int retransmitted_packet_count_;
  75   // Number of bytes that had to be retransmitted.
  76   int retransmitted_byte_count_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(QuicAckNotifier);
  79 };
  80
  81 }  // namespace net
  82
  83 #endif  // NET_QUIC_QUIC_ACK_NOTIFIER_H_