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     virtual void OnAckNotification() = 0;
  25
  26    protected:
  27     friend class base::RefCounted<DelegateInterface>;
  28
  29     // Delegates are ref counted.
  30     virtual ~DelegateInterface();
  31   };
  32
  33   // QuicAckNotifier is expected to keep its own reference to the delegate.
  34   explicit QuicAckNotifier(DelegateInterface* delegate);
  35   virtual ~QuicAckNotifier();
  36
  37   // Register a sequence number that this AckNotifier should be interested in.
  38   void AddSequenceNumber(const QuicPacketSequenceNumber& sequence_number);
  39
  40   // Register a set of sequence numbers that this AckNotifier should be
  41   // interested in.
  42   void AddSequenceNumbers(const SequenceNumberSet& sequence_numbers);
  43
  44   // Called by the QuicConnection on receipt of new ACK frame, with the sequence
  45   // number referenced by the ACK frame.
  46   // Deletes the matching sequence number from the stored set of sequence
  47   // numbers. If this set is now empty, call the stored delegate's
  48   // OnAckNotification method.
  49   //
  50   // Returns true if the provided sequence_number caused the delegate to be
  51   // called, false otherwise.
  52   bool OnAck(QuicPacketSequenceNumber sequence_number);
  53
  54   bool IsEmpty() { return sequence_numbers_.empty(); }
  55
  56   // If a packet is retransmitted by the connection it will be sent with a
  57   // different sequence number. Updates our internal set of sequence_numbers to
  58   // track the latest number.
  59   void UpdateSequenceNumber(QuicPacketSequenceNumber old_sequence_number,
  60                             QuicPacketSequenceNumber new_sequence_number);
  61
  62  private:
  63   // The delegate's OnAckNotification() method will be called once we have been
  64   // notified of ACKs for all the sequence numbers we are tracking.
  65   // This is not owned by OnAckNotifier and must outlive it.
  66   scoped_refptr<DelegateInterface> delegate_;
  67
  68   // Set of sequence numbers this notifier is waiting to hear about. The
  69   // delegate will not be called until this is an empty set.
  70   SequenceNumberSet sequence_numbers_;
  71 };
  72
  73 };  // namespace net
  74
  75 #endif  // NET_QUIC_QUIC_ACK_NOTIFIER_H_