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// Copyright (c) 2012 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 "remoting/protocol/content_description.h"
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "remoting/base/constants.h"
#include "remoting/protocol/authenticator.h"
#include "remoting/protocol/name_value_map.h"
#include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
using buzz::QName;
using buzz::XmlElement;
namespace remoting {
namespace protocol {
const char ContentDescription::kChromotingContentName[] = "chromoting";
namespace {
const char kDefaultNs[] = "";
// Following constants are used to format session description in XML.
const char kDescriptionTag[] = "description";
const char kControlTag[] = "control";
const char kEventTag[] = "event";
const char kVideoTag[] = "video";
const char kAudioTag[] = "audio";
const char kDeprecatedResolutionTag[] = "initial-resolution";
const char kTransportAttr[] = "transport";
const char kVersionAttr[] = "version";
const char kCodecAttr[] = "codec";
const char kDeprecatedWidthAttr[] = "width";
const char kDeprecatedHeightAttr[] = "height";
const NameMapElement<ChannelConfig::TransportType> kTransports[] = {
{ ChannelConfig::TRANSPORT_STREAM, "stream" },
{ ChannelConfig::TRANSPORT_MUX_STREAM, "mux-stream" },
{ ChannelConfig::TRANSPORT_DATAGRAM, "datagram" },
{ ChannelConfig::TRANSPORT_NONE, "none" },
};
const NameMapElement<ChannelConfig::Codec> kCodecs[] = {
{ ChannelConfig::CODEC_VERBATIM, "verbatim" },
{ ChannelConfig::CODEC_VP8, "vp8" },
{ ChannelConfig::CODEC_ZIP, "zip" },
{ ChannelConfig::CODEC_OPUS, "opus" },
{ ChannelConfig::CODEC_SPEEX, "speex" },
};
// Format a channel configuration tag for chromotocol session description,
// e.g. for video channel:
// <video transport="stream" version="1" codec="vp8" />
XmlElement* FormatChannelConfig(const ChannelConfig& config,
const std::string& tag_name) {
XmlElement* result = new XmlElement(
QName(kChromotingXmlNamespace, tag_name));
result->AddAttr(QName(kDefaultNs, kTransportAttr),
ValueToName(kTransports, config.transport));
if (config.transport != ChannelConfig::TRANSPORT_NONE) {
result->AddAttr(QName(kDefaultNs, kVersionAttr),
base::IntToString(config.version));
if (config.codec != ChannelConfig::CODEC_UNDEFINED) {
result->AddAttr(QName(kDefaultNs, kCodecAttr),
ValueToName(kCodecs, config.codec));
}
}
return result;
}
// Returns false if the element is invalid.
bool ParseChannelConfig(const XmlElement* element, bool codec_required,
ChannelConfig* config) {
if (!NameToValue(
kTransports, element->Attr(QName(kDefaultNs, kTransportAttr)),
&config->transport)) {
return false;
}
// Version is not required when transport="none".
if (config->transport != ChannelConfig::TRANSPORT_NONE) {
if (!base::StringToInt(element->Attr(QName(kDefaultNs, kVersionAttr)),
&config->version)) {
return false;
}
// Codec is not required when transport="none".
if (codec_required) {
if (!NameToValue(kCodecs, element->Attr(QName(kDefaultNs, kCodecAttr)),
&config->codec)) {
return false;
}
} else {
config->codec = ChannelConfig::CODEC_UNDEFINED;
}
} else {
config->version = 0;
config->codec = ChannelConfig::CODEC_UNDEFINED;
}
return true;
}
} // namespace
ContentDescription::ContentDescription(
scoped_ptr<CandidateSessionConfig> config,
scoped_ptr<buzz::XmlElement> authenticator_message)
: candidate_config_(config.Pass()),
authenticator_message_(authenticator_message.Pass()) {
}
ContentDescription::~ContentDescription() { }
ContentDescription* ContentDescription::Copy() const {
if (!candidate_config_.get() || !authenticator_message_.get()) {
return NULL;
}
scoped_ptr<XmlElement> message(new XmlElement(*authenticator_message_));
return new ContentDescription(candidate_config_->Clone(), message.Pass());
}
// ToXml() creates content description for chromoting session. The
// description looks as follows:
// <description xmlns="google:remoting">
// <control transport="stream" version="1" />
// <event transport="datagram" version="1" />
// <video transport="stream" codec="vp8" version="1" />
// <audio transport="stream" codec="opus" version="1" />
// <authentication>
// Message created by Authenticator implementation.
// </authentication>
// </description>
//
XmlElement* ContentDescription::ToXml() const {
XmlElement* root = new XmlElement(
QName(kChromotingXmlNamespace, kDescriptionTag), true);
std::vector<ChannelConfig>::const_iterator it;
for (it = config()->control_configs().begin();
it != config()->control_configs().end(); ++it) {
root->AddElement(FormatChannelConfig(*it, kControlTag));
}
for (it = config()->event_configs().begin();
it != config()->event_configs().end(); ++it) {
root->AddElement(FormatChannelConfig(*it, kEventTag));
}
for (it = config()->video_configs().begin();
it != config()->video_configs().end(); ++it) {
root->AddElement(FormatChannelConfig(*it, kVideoTag));
}
for (it = config()->audio_configs().begin();
it != config()->audio_configs().end(); ++it) {
ChannelConfig config = *it;
root->AddElement(FormatChannelConfig(config, kAudioTag));
}
// Older endpoints require an initial-resolution tag, but otherwise ignore it.
XmlElement* resolution_tag = new XmlElement(
QName(kChromotingXmlNamespace, kDeprecatedResolutionTag));
resolution_tag->AddAttr(QName(kDefaultNs, kDeprecatedWidthAttr), "640");
resolution_tag->AddAttr(QName(kDefaultNs, kDeprecatedHeightAttr), "480");
root->AddElement(resolution_tag);
if (authenticator_message_.get()) {
DCHECK(Authenticator::IsAuthenticatorMessage(authenticator_message_.get()));
root->AddElement(new XmlElement(*authenticator_message_));
}
return root;
}
// static
// Adds the channel configs corresponding to |tag_name|,
// found in |element|, to |configs|.
bool ContentDescription::ParseChannelConfigs(
const XmlElement* const element,
const char tag_name[],
bool codec_required,
bool optional,
std::vector<ChannelConfig>* const configs) {
QName tag(kChromotingXmlNamespace, tag_name);
const XmlElement* child = element->FirstNamed(tag);
while (child) {
ChannelConfig channel_config;
if (ParseChannelConfig(child, codec_required, &channel_config)) {
configs->push_back(channel_config);
}
child = child->NextNamed(tag);
}
if (optional && configs->empty()) {
// If there's no mention of the tag, implicitly assume disabled channel.
configs->push_back(ChannelConfig::None());
}
return true;
}
// static
scoped_ptr<ContentDescription> ContentDescription::ParseXml(
const XmlElement* element) {
if (element->Name() != QName(kChromotingXmlNamespace, kDescriptionTag)) {
LOG(ERROR) << "Invalid description: " << element->Str();
return scoped_ptr<ContentDescription>();
}
scoped_ptr<CandidateSessionConfig> config(
CandidateSessionConfig::CreateEmpty());
if (!ParseChannelConfigs(element, kControlTag, false, false,
config->mutable_control_configs()) ||
!ParseChannelConfigs(element, kEventTag, false, false,
config->mutable_event_configs()) ||
!ParseChannelConfigs(element, kVideoTag, true, false,
config->mutable_video_configs()) ||
!ParseChannelConfigs(element, kAudioTag, true, true,
config->mutable_audio_configs())) {
return scoped_ptr<ContentDescription>();
}
scoped_ptr<XmlElement> authenticator_message;
const XmlElement* child = Authenticator::FindAuthenticatorMessage(element);
if (child)
authenticator_message.reset(new XmlElement(*child));
return scoped_ptr<ContentDescription>(
new ContentDescription(config.Pass(), authenticator_message.Pass()));
}
} // namespace protocol
} // namespace remoting
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