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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/cast/pacing/paced_sender.h"
#include "base/bind.h"
#include "base/message_loop/message_loop.h"
namespace media {
namespace cast {
static const int64 kPacingIntervalMs = 10;
// Each frame will be split into no more than kPacingMaxBurstsPerFrame
// bursts of packets.
static const size_t kPacingMaxBurstsPerFrame = 3;
PacedSender::PacedSender(scoped_refptr<CastEnvironment> cast_environment,
PacketSender* transport)
: cast_environment_(cast_environment),
burst_size_(1),
packets_sent_in_burst_(0),
transport_(transport),
weak_factory_(this) {
ScheduleNextSend();
}
PacedSender::~PacedSender() {}
bool PacedSender::SendPackets(const PacketList& packets) {
DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
cast_environment_->Logging()->InsertPacketListEvent(kPacketSentToPacer,
packets);
return SendPacketsToTransport(packets, &packet_list_);
}
bool PacedSender::ResendPackets(const PacketList& packets) {
DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
cast_environment_->Logging()->InsertPacketListEvent(kPacketRetransmited,
packets);
return SendPacketsToTransport(packets, &resend_packet_list_);
}
bool PacedSender::SendPacketsToTransport(const PacketList& packets,
PacketList* packets_not_sent) {
DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
UpdateBurstSize(packets.size());
if (!packets_not_sent->empty()) {
packets_not_sent->insert(packets_not_sent->end(),
packets.begin(), packets.end());
return true;
}
PacketList packets_to_send;
PacketList::const_iterator first_to_store_it = packets.begin();
size_t max_packets_to_send_now = burst_size_ - packets_sent_in_burst_;
if (max_packets_to_send_now > 0) {
size_t packets_to_send_now = std::min(max_packets_to_send_now,
packets.size());
std::advance(first_to_store_it, packets_to_send_now);
packets_to_send.insert(packets_to_send.begin(),
packets.begin(), first_to_store_it);
}
packets_not_sent->insert(packets_not_sent->end(),
first_to_store_it, packets.end());
packets_sent_in_burst_ += packets_to_send.size();
if (packets_to_send.empty()) return true;
cast_environment_->Logging()->InsertPacketListEvent(kPacketSentToNetwork,
packets);
return transport_->SendPackets(packets_to_send);
}
bool PacedSender::SendRtcpPacket(const Packet& packet) {
DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
// We pass the RTCP packets straight through.
return transport_->SendPacket(packet);
}
void PacedSender::ScheduleNextSend() {
base::TimeDelta time_to_next = time_last_process_ -
cast_environment_->Clock()->NowTicks() +
base::TimeDelta::FromMilliseconds(kPacingIntervalMs);
time_to_next = std::max(time_to_next, base::TimeDelta());
cast_environment_->PostDelayedTask(CastEnvironment::MAIN, FROM_HERE,
base::Bind(&PacedSender::SendNextPacketBurst, weak_factory_.GetWeakPtr()),
time_to_next);
}
void PacedSender::SendNextPacketBurst() {
DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
SendStoredPackets();
time_last_process_ = cast_environment_->Clock()->NowTicks();
ScheduleNextSend();
}
void PacedSender::SendStoredPackets() {
DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
if (packet_list_.empty() && resend_packet_list_.empty()) return;
size_t packets_to_send = burst_size_;
PacketList packets_to_resend;
// Send our re-send packets first.
if (!resend_packet_list_.empty()) {
PacketList::iterator it = resend_packet_list_.begin();
size_t packets_to_send_now = std::min(packets_to_send,
resend_packet_list_.size());
std::advance(it, packets_to_send_now);
packets_to_resend.insert(packets_to_resend.begin(),
resend_packet_list_.begin(), it);
resend_packet_list_.erase(resend_packet_list_.begin(), it);
packets_to_send -= packets_to_resend.size();
}
if (!packet_list_.empty() && packets_to_send > 0) {
PacketList::iterator it = packet_list_.begin();
size_t packets_to_send_now = std::min(packets_to_send,
packet_list_.size());
std::advance(it, packets_to_send_now);
packets_to_resend.insert(packets_to_resend.end(),
packet_list_.begin(), it);
packet_list_.erase(packet_list_.begin(), it);
if (packet_list_.empty()) {
burst_size_ = 1; // Reset burst size after we sent the last stored packet
packets_sent_in_burst_ = 0;
}
}
transport_->SendPackets(packets_to_resend);
}
void PacedSender::UpdateBurstSize(size_t packets_to_send) {
DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
packets_to_send = std::max(packets_to_send,
resend_packet_list_.size() + packet_list_.size());
packets_to_send += (kPacingMaxBurstsPerFrame - 1); // Round up.
burst_size_ = std::max(packets_to_send / kPacingMaxBurstsPerFrame,
burst_size_);
}
} // namespace cast
} // namespace media
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