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      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 #include "net/quic/quic_ack_notifier_manager.h"
      6 
      7 #include <stddef.h>
      8 #include <list>
      9 #include <map>
     10 #include <utility>
     11 #include <vector>
     12 
     13 #include "base/stl_util.h"
     14 #include "net/quic/quic_ack_notifier.h"
     15 #include "net/quic/quic_protocol.h"
     16 
     17 namespace net {
     18 
     19 AckNotifierManager::AckNotifierManager() {}
     20 
     21 AckNotifierManager::~AckNotifierManager() {
     22   STLDeleteElements(&ack_notifiers_);
     23 }
     24 
     25 void AckNotifierManager::OnPacketAcked(
     26     QuicPacketSequenceNumber sequence_number,
     27     QuicTime::Delta delta_largest_observed) {
     28   // Inform all the registered AckNotifiers of the new ACK.
     29   AckNotifierMap::iterator map_it = ack_notifier_map_.find(sequence_number);
     30   if (map_it == ack_notifier_map_.end()) {
     31     // No AckNotifier is interested in this sequence number.
     32     return;
     33   }
     34 
     35   // One or more AckNotifiers are registered as interested in this sequence
     36   // number. Iterate through them and call OnAck on each.
     37   for (AckNotifierSet::iterator set_it = map_it->second.begin();
     38        set_it != map_it->second.end(); ++set_it) {
     39     QuicAckNotifier* ack_notifier = *set_it;
     40     ack_notifier->OnAck(sequence_number, delta_largest_observed);
     41 
     42     // If this has resulted in an empty AckNotifer, erase it.
     43     if (ack_notifier->IsEmpty()) {
     44       delete ack_notifier;
     45       ack_notifiers_.erase(ack_notifier);
     46     }
     47   }
     48 
     49   // Remove the sequence number from the map as we have notified all the
     50   // registered AckNotifiers, and we won't see it again.
     51   ack_notifier_map_.erase(map_it);
     52 }
     53 
     54 void AckNotifierManager::UpdateSequenceNumber(
     55     QuicPacketSequenceNumber old_sequence_number,
     56     QuicPacketSequenceNumber new_sequence_number) {
     57   AckNotifierMap::iterator map_it = ack_notifier_map_.find(old_sequence_number);
     58   if (map_it != ack_notifier_map_.end()) {
     59     // We will add an entry to the map for the new sequence number, and move
     60     // the
     61     // list of AckNotifiers over.
     62     AckNotifierSet new_set;
     63     for (AckNotifierSet::iterator notifier_it = map_it->second.begin();
     64          notifier_it != map_it->second.end(); ++notifier_it) {
     65       (*notifier_it)
     66           ->UpdateSequenceNumber(old_sequence_number, new_sequence_number);
     67       new_set.insert(*notifier_it);
     68     }
     69     ack_notifier_map_[new_sequence_number] = new_set;
     70     ack_notifier_map_.erase(map_it);
     71   }
     72 }
     73 
     74 void AckNotifierManager::OnSerializedPacket(
     75     const SerializedPacket& serialized_packet) {
     76   // Run through all the frames and if any of them are stream frames and have
     77   // an AckNotifier registered, then inform the AckNotifier that it should be
     78   // interested in this packet's sequence number.
     79 
     80   RetransmittableFrames* frames = serialized_packet.retransmittable_frames;
     81 
     82   // AckNotifiers can only be attached to retransmittable frames.
     83   if (!frames) {
     84     return;
     85   }
     86 
     87   for (QuicFrames::const_iterator it = frames->frames().begin();
     88        it != frames->frames().end(); ++it) {
     89     if (it->type == STREAM_FRAME && it->stream_frame->notifier != NULL) {
     90       QuicAckNotifier* notifier = it->stream_frame->notifier;
     91 
     92       // The AckNotifier needs to know it is tracking this packet's sequence
     93       // number.
     94       notifier->AddSequenceNumber(serialized_packet.sequence_number,
     95                                   serialized_packet.packet->length());
     96 
     97       // Update the mapping in the other direction, from sequence
     98       // number to AckNotifier.
     99       ack_notifier_map_[serialized_packet.sequence_number].insert(notifier);
    100 
    101       // Take ownership of the AckNotifier.
    102       ack_notifiers_.insert(notifier);
    103     }
    104   }
    105 }
    106 
    107 }  // namespace net
    108