webrtc/libjingle/session/media/mediamessages.cc - platform/external/webrtc - Git at Google

 /*
  * libjingle
  * Copyright 2010 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
  *     this list of conditions and the following disclaimer in the documentation
  *     and/or other materials provided with the distribution.
  *  3. The name of the author may not be used to endorse or promote products
  *     derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 /*
  * Documentation is in mediamessages.h.
  */

 #include "webrtc/libjingle/session/media/mediamessages.h"

 #include "webrtc/p2p/base/constants.h"
 #include "webrtc/libjingle/session/media/mediasessionclient.h"
 #include "webrtc/libjingle/xmllite/xmlelement.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/stringencode.h"

 namespace cricket {

 namespace {

 bool ParseSsrc(const std::string& string, uint32* ssrc) {
   return rtc::FromString(string, ssrc);
 }

 // Builds a <view> element according to the following spec:
 // goto/jinglemuc
 buzz::XmlElement* CreateViewElem(const std::string& name,
                                  const std::string& type) {
   buzz::XmlElement* view_elem =
       new buzz::XmlElement(QN_JINGLE_DRAFT_VIEW, true);
   view_elem->AddAttr(QN_NAME, name);
   view_elem->SetAttr(QN_TYPE, type);
   return view_elem;
 }

 buzz::XmlElement* CreateVideoViewElem(const std::string& content_name,
                                       const std::string& type) {
   return CreateViewElem(content_name, type);
 }

 buzz::XmlElement* CreateNoneVideoViewElem(const std::string& content_name) {
   return CreateVideoViewElem(content_name, STR_JINGLE_DRAFT_VIEW_TYPE_NONE);
 }

 buzz::XmlElement* CreateStaticVideoViewElem(const std::string& content_name,
                                             const StaticVideoView& view) {
   buzz::XmlElement* view_elem =
       CreateVideoViewElem(content_name, STR_JINGLE_DRAFT_VIEW_TYPE_STATIC);
   AddXmlAttr(view_elem, QN_SSRC, view.selector.ssrc);

   buzz::XmlElement* params_elem = new buzz::XmlElement(QN_JINGLE_DRAFT_PARAMS);
   AddXmlAttr(params_elem, QN_WIDTH, view.width);
   AddXmlAttr(params_elem, QN_HEIGHT, view.height);
   AddXmlAttr(params_elem, QN_FRAMERATE, view.framerate);
   AddXmlAttr(params_elem, QN_PREFERENCE, view.preference);
   view_elem->AddElement(params_elem);

   return view_elem;
 }

 }  //  namespace

 bool IsJingleViewRequest(const buzz::XmlElement* action_elem) {
   return action_elem->FirstNamed(QN_JINGLE_DRAFT_VIEW) != NULL;
 }

 bool ParseStaticVideoView(const buzz::XmlElement* view_elem,
                           StaticVideoView* view,
                           ParseError* error) {
   uint32 ssrc;
   if (!ParseSsrc(view_elem->Attr(QN_SSRC), &ssrc)) {
     return BadParse("Invalid or missing view ssrc.", error);
   }
   view->selector = StreamSelector(ssrc);

   const buzz::XmlElement* params_elem =
       view_elem->FirstNamed(QN_JINGLE_DRAFT_PARAMS);
   if (params_elem) {
     view->width = GetXmlAttr(params_elem, QN_WIDTH, 0);
     view->height = GetXmlAttr(params_elem, QN_HEIGHT, 0);
     view->framerate = GetXmlAttr(params_elem, QN_FRAMERATE, 0);
     view->preference = GetXmlAttr(params_elem, QN_PREFERENCE, 0);
   } else {
     return BadParse("Missing view params.", error);
   }

   return true;
 }

 bool ParseJingleViewRequest(const buzz::XmlElement* action_elem,
                             ViewRequest* view_request,
                             ParseError* error) {
   for (const buzz::XmlElement* view_elem =
            action_elem->FirstNamed(QN_JINGLE_DRAFT_VIEW);
        view_elem != NULL;
        view_elem = view_elem->NextNamed(QN_JINGLE_DRAFT_VIEW)) {
     std::string type = view_elem->Attr(QN_TYPE);
     if (STR_JINGLE_DRAFT_VIEW_TYPE_NONE == type) {
       view_request->static_video_views.clear();
       return true;
     } else if (STR_JINGLE_DRAFT_VIEW_TYPE_STATIC == type) {
       StaticVideoView static_video_view(StreamSelector(0), 0, 0, 0);
       if (!ParseStaticVideoView(view_elem, &static_video_view, error)) {
         return false;
       }
       view_request->static_video_views.push_back(static_video_view);
     } else {
       LOG(LS_INFO) << "Ingnoring unknown view type: " << type;
     }
   }
   return true;
 }

 bool WriteJingleViewRequest(const std::string& content_name,
                             const ViewRequest& request,
                             XmlElements* elems,
                             WriteError* error) {
   if (request.static_video_views.empty()) {
     elems->push_back(CreateNoneVideoViewElem(content_name));
   } else {
     for (StaticVideoViews::const_iterator view =
              request.static_video_views.begin();
          view != request.static_video_views.end(); ++view) {
       elems->push_back(CreateStaticVideoViewElem(content_name, *view));
     }
   }
   return true;
 }

 bool ParseSsrcAsLegacyStream(const buzz::XmlElement* desc_elem,
                              std::vector<StreamParams>* streams,
                              ParseError* error) {
   const std::string ssrc_str = desc_elem->Attr(QN_SSRC);
   if (!ssrc_str.empty()) {
     uint32 ssrc;
     if (!ParseSsrc(ssrc_str, &ssrc)) {
       return BadParse("Missing or invalid ssrc.", error);
     }

     streams->push_back(StreamParams::CreateLegacy(ssrc));
   }
   return true;
 }

 bool ParseSsrcs(const buzz::XmlElement* parent_elem,
                 std::vector<uint32>* ssrcs,
                 ParseError* error) {
   for (const buzz::XmlElement* ssrc_elem =
            parent_elem->FirstNamed(QN_JINGLE_DRAFT_SSRC);
        ssrc_elem != NULL;
        ssrc_elem = ssrc_elem->NextNamed(QN_JINGLE_DRAFT_SSRC)) {
     uint32 ssrc;
     if (!ParseSsrc(ssrc_elem->BodyText(), &ssrc)) {
       return BadParse("Missing or invalid ssrc.", error);
     }

     ssrcs->push_back(ssrc);
   }
   return true;
 }

 bool ParseSsrcGroups(const buzz::XmlElement* parent_elem,
                      std::vector<SsrcGroup>* ssrc_groups,
                      ParseError* error) {
   for (const buzz::XmlElement* group_elem =
            parent_elem->FirstNamed(QN_JINGLE_DRAFT_SSRC_GROUP);
        group_elem != NULL;
        group_elem = group_elem->NextNamed(QN_JINGLE_DRAFT_SSRC_GROUP)) {
     std::string semantics = group_elem->Attr(QN_SEMANTICS);
     std::vector<uint32> ssrcs;
     if (!ParseSsrcs(group_elem, &ssrcs, error)) {
       return false;
     }
     ssrc_groups->push_back(SsrcGroup(semantics, ssrcs));
   }
   return true;
 }

 bool ParseJingleStream(const buzz::XmlElement* stream_elem,
                        std::vector<StreamParams>* streams,
                        ParseError* error) {
   StreamParams stream;
   // We treat the nick as a stream groupid.
   stream.groupid = stream_elem->Attr(QN_NICK);
   stream.id = stream_elem->Attr(QN_NAME);
   stream.type = stream_elem->Attr(QN_TYPE);
   stream.display = stream_elem->Attr(QN_DISPLAY);
   stream.cname = stream_elem->Attr(QN_CNAME);
   if (!ParseSsrcs(stream_elem, &(stream.ssrcs), error)) {
     return false;
   }
   std::vector<SsrcGroup> ssrc_groups;
   if (!ParseSsrcGroups(stream_elem, &(stream.ssrc_groups), error)) {
     return false;
   }
   streams->push_back(stream);
   return true;
 }

 bool ParseJingleRtpHeaderExtensions(const buzz::XmlElement* parent_elem,
                                     std::vector<RtpHeaderExtension>* hdrexts,
                                     ParseError* error) {
   for (const buzz::XmlElement* hdrext_elem =
            parent_elem->FirstNamed(QN_JINGLE_RTP_HDREXT);
        hdrext_elem != NULL;
        hdrext_elem = hdrext_elem->NextNamed(QN_JINGLE_RTP_HDREXT)) {
     std::string uri = hdrext_elem->Attr(QN_URI);
     int id = GetXmlAttr(hdrext_elem, QN_ID, 0);
     if (id <= 0) {
       return BadParse("Invalid RTP header extension id.", error);
     }
     hdrexts->push_back(RtpHeaderExtension(uri, id));
   }
   return true;
 }

 bool HasJingleStreams(const buzz::XmlElement* desc_elem) {
   const buzz::XmlElement* streams_elem =
       desc_elem->FirstNamed(QN_JINGLE_DRAFT_STREAMS);
   return (streams_elem != NULL);
 }

 bool ParseJingleStreams(const buzz::XmlElement* desc_elem,
                         std::vector<StreamParams>* streams,
                         ParseError* error) {
   const buzz::XmlElement* streams_elem =
       desc_elem->FirstNamed(QN_JINGLE_DRAFT_STREAMS);
   if (streams_elem == NULL) {
     return BadParse("Missing streams element.", error);
   }
   for (const buzz::XmlElement* stream_elem =
            streams_elem->FirstNamed(QN_JINGLE_DRAFT_STREAM);
        stream_elem != NULL;
        stream_elem = stream_elem->NextNamed(QN_JINGLE_DRAFT_STREAM)) {
     if (!ParseJingleStream(stream_elem, streams, error)) {
       return false;
     }
   }
   return true;
 }

 void WriteSsrcs(const std::vector<uint32>& ssrcs,
                 buzz::XmlElement* parent_elem) {
   for (std::vector<uint32>::const_iterator ssrc = ssrcs.begin();
        ssrc != ssrcs.end(); ++ssrc) {
     buzz::XmlElement* ssrc_elem =
         new buzz::XmlElement(QN_JINGLE_DRAFT_SSRC, false);
     SetXmlBody(ssrc_elem, *ssrc);

     parent_elem->AddElement(ssrc_elem);
   }
 }

 void WriteSsrcGroups(const std::vector<SsrcGroup>& groups,
                      buzz::XmlElement* parent_elem) {
   for (std::vector<SsrcGroup>::const_iterator group = groups.begin();
        group != groups.end(); ++group) {
     buzz::XmlElement* group_elem =
         new buzz::XmlElement(QN_JINGLE_DRAFT_SSRC_GROUP, false);
     AddXmlAttrIfNonEmpty(group_elem, QN_SEMANTICS, group->semantics);
     WriteSsrcs(group->ssrcs, group_elem);

     parent_elem->AddElement(group_elem);
   }
 }

 void WriteJingleStream(const StreamParams& stream,
                        buzz::XmlElement* parent_elem) {
   buzz::XmlElement* stream_elem =
       new buzz::XmlElement(QN_JINGLE_DRAFT_STREAM, false);
   // We treat the nick as a stream groupid.
   AddXmlAttrIfNonEmpty(stream_elem, QN_NICK, stream.groupid);
   AddXmlAttrIfNonEmpty(stream_elem, QN_NAME, stream.id);
   AddXmlAttrIfNonEmpty(stream_elem, QN_TYPE, stream.type);
   AddXmlAttrIfNonEmpty(stream_elem, QN_DISPLAY, stream.display);
   AddXmlAttrIfNonEmpty(stream_elem, QN_CNAME, stream.cname);
   WriteSsrcs(stream.ssrcs, stream_elem);
   WriteSsrcGroups(stream.ssrc_groups, stream_elem);

   parent_elem->AddElement(stream_elem);
 }

 void WriteJingleStreams(const std::vector<StreamParams>& streams,
                         buzz::XmlElement* parent_elem) {
   buzz::XmlElement* streams_elem =
       new buzz::XmlElement(QN_JINGLE_DRAFT_STREAMS, true);
   for (std::vector<StreamParams>::const_iterator stream = streams.begin();
        stream != streams.end(); ++stream) {
     WriteJingleStream(*stream, streams_elem);
   }

   parent_elem->AddElement(streams_elem);
 }

 void WriteJingleRtpHeaderExtensions(
     const std::vector<RtpHeaderExtension>& hdrexts,
     buzz::XmlElement* parent_elem) {
   for (std::vector<RtpHeaderExtension>::const_iterator hdrext = hdrexts.begin();
        hdrext != hdrexts.end(); ++hdrext) {
     buzz::XmlElement* hdrext_elem =
       new buzz::XmlElement(QN_JINGLE_RTP_HDREXT, false);
     AddXmlAttr(hdrext_elem, QN_URI, hdrext->uri);
     AddXmlAttr(hdrext_elem, QN_ID, hdrext->id);
     parent_elem->AddElement(hdrext_elem);
   }
 }


 }  // namespace cricket
	/*
	* libjingle
	* Copyright 2010 Google Inc.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	* 3. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
	* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	/*
	* Documentation is in mediamessages.h.
	*/

	#include "webrtc/libjingle/session/media/mediamessages.h"

	#include "webrtc/p2p/base/constants.h"
	#include "webrtc/libjingle/session/media/mediasessionclient.h"
	#include "webrtc/libjingle/xmllite/xmlelement.h"
	#include "webrtc/base/logging.h"
	#include "webrtc/base/stringencode.h"

	namespace cricket {

	namespace {

	bool ParseSsrc(const std::string& string, uint32* ssrc) {
	return rtc::FromString(string, ssrc);
	}

	// Builds a <view> element according to the following spec:
	// goto/jinglemuc
	buzz::XmlElement* CreateViewElem(const std::string& name,
	const std::string& type) {
	buzz::XmlElement* view_elem =
	new buzz::XmlElement(QN_JINGLE_DRAFT_VIEW, true);
	view_elem->AddAttr(QN_NAME, name);
	view_elem->SetAttr(QN_TYPE, type);
	return view_elem;
	}

	buzz::XmlElement* CreateVideoViewElem(const std::string& content_name,
	const std::string& type) {
	return CreateViewElem(content_name, type);
	}

	buzz::XmlElement* CreateNoneVideoViewElem(const std::string& content_name) {
	return CreateVideoViewElem(content_name, STR_JINGLE_DRAFT_VIEW_TYPE_NONE);
	}

	buzz::XmlElement* CreateStaticVideoViewElem(const std::string& content_name,
	const StaticVideoView& view) {
	buzz::XmlElement* view_elem =
	CreateVideoViewElem(content_name, STR_JINGLE_DRAFT_VIEW_TYPE_STATIC);
	AddXmlAttr(view_elem, QN_SSRC, view.selector.ssrc);

	buzz::XmlElement* params_elem = new buzz::XmlElement(QN_JINGLE_DRAFT_PARAMS);
	AddXmlAttr(params_elem, QN_WIDTH, view.width);
	AddXmlAttr(params_elem, QN_HEIGHT, view.height);
	AddXmlAttr(params_elem, QN_FRAMERATE, view.framerate);
	AddXmlAttr(params_elem, QN_PREFERENCE, view.preference);
	view_elem->AddElement(params_elem);

	return view_elem;
	}

	} // namespace

	bool IsJingleViewRequest(const buzz::XmlElement* action_elem) {
	return action_elem->FirstNamed(QN_JINGLE_DRAFT_VIEW) != NULL;
	}

	bool ParseStaticVideoView(const buzz::XmlElement* view_elem,
	StaticVideoView* view,
	ParseError* error) {
	uint32 ssrc;
	if (!ParseSsrc(view_elem->Attr(QN_SSRC), &ssrc)) {
	return BadParse("Invalid or missing view ssrc.", error);
	}
	view->selector = StreamSelector(ssrc);

	const buzz::XmlElement* params_elem =
	view_elem->FirstNamed(QN_JINGLE_DRAFT_PARAMS);
	if (params_elem) {
	view->width = GetXmlAttr(params_elem, QN_WIDTH, 0);
	view->height = GetXmlAttr(params_elem, QN_HEIGHT, 0);
	view->framerate = GetXmlAttr(params_elem, QN_FRAMERATE, 0);
	view->preference = GetXmlAttr(params_elem, QN_PREFERENCE, 0);
	} else {
	return BadParse("Missing view params.", error);
	}

	return true;
	}

	bool ParseJingleViewRequest(const buzz::XmlElement* action_elem,
	ViewRequest* view_request,
	ParseError* error) {
	for (const buzz::XmlElement* view_elem =
	action_elem->FirstNamed(QN_JINGLE_DRAFT_VIEW);
	view_elem != NULL;
	view_elem = view_elem->NextNamed(QN_JINGLE_DRAFT_VIEW)) {
	std::string type = view_elem->Attr(QN_TYPE);
	if (STR_JINGLE_DRAFT_VIEW_TYPE_NONE == type) {
	view_request->static_video_views.clear();
	return true;
	} else if (STR_JINGLE_DRAFT_VIEW_TYPE_STATIC == type) {
	StaticVideoView static_video_view(StreamSelector(0), 0, 0, 0);
	if (!ParseStaticVideoView(view_elem, &static_video_view, error)) {
	return false;
	}
	view_request->static_video_views.push_back(static_video_view);
	} else {
	LOG(LS_INFO) << "Ingnoring unknown view type: " << type;
	}
	}
	return true;
	}

	bool WriteJingleViewRequest(const std::string& content_name,
	const ViewRequest& request,
	XmlElements* elems,
	WriteError* error) {
	if (request.static_video_views.empty()) {
	elems->push_back(CreateNoneVideoViewElem(content_name));
	} else {
	for (StaticVideoViews::const_iterator view =
	request.static_video_views.begin();
	view != request.static_video_views.end(); ++view) {
	elems->push_back(CreateStaticVideoViewElem(content_name, *view));
	}
	}
	return true;
	}

	bool ParseSsrcAsLegacyStream(const buzz::XmlElement* desc_elem,
	std::vector<StreamParams>* streams,
	ParseError* error) {
	const std::string ssrc_str = desc_elem->Attr(QN_SSRC);
	if (!ssrc_str.empty()) {
	uint32 ssrc;
	if (!ParseSsrc(ssrc_str, &ssrc)) {
	return BadParse("Missing or invalid ssrc.", error);
	}

	streams->push_back(StreamParams::CreateLegacy(ssrc));
	}
	return true;
	}

	bool ParseSsrcs(const buzz::XmlElement* parent_elem,
	std::vector<uint32>* ssrcs,
	ParseError* error) {
	for (const buzz::XmlElement* ssrc_elem =
	parent_elem->FirstNamed(QN_JINGLE_DRAFT_SSRC);
	ssrc_elem != NULL;
	ssrc_elem = ssrc_elem->NextNamed(QN_JINGLE_DRAFT_SSRC)) {
	uint32 ssrc;
	if (!ParseSsrc(ssrc_elem->BodyText(), &ssrc)) {
	return BadParse("Missing or invalid ssrc.", error);
	}

	ssrcs->push_back(ssrc);
	}
	return true;
	}

	bool ParseSsrcGroups(const buzz::XmlElement* parent_elem,
	std::vector<SsrcGroup>* ssrc_groups,
	ParseError* error) {
	for (const buzz::XmlElement* group_elem =
	parent_elem->FirstNamed(QN_JINGLE_DRAFT_SSRC_GROUP);
	group_elem != NULL;
	group_elem = group_elem->NextNamed(QN_JINGLE_DRAFT_SSRC_GROUP)) {
	std::string semantics = group_elem->Attr(QN_SEMANTICS);
	std::vector<uint32> ssrcs;
	if (!ParseSsrcs(group_elem, &ssrcs, error)) {
	return false;
	}
	ssrc_groups->push_back(SsrcGroup(semantics, ssrcs));
	}
	return true;
	}

	bool ParseJingleStream(const buzz::XmlElement* stream_elem,
	std::vector<StreamParams>* streams,
	ParseError* error) {
	StreamParams stream;
	// We treat the nick as a stream groupid.
	stream.groupid = stream_elem->Attr(QN_NICK);
	stream.id = stream_elem->Attr(QN_NAME);
	stream.type = stream_elem->Attr(QN_TYPE);
	stream.display = stream_elem->Attr(QN_DISPLAY);
	stream.cname = stream_elem->Attr(QN_CNAME);
	if (!ParseSsrcs(stream_elem, &(stream.ssrcs), error)) {
	return false;
	}
	std::vector<SsrcGroup> ssrc_groups;
	if (!ParseSsrcGroups(stream_elem, &(stream.ssrc_groups), error)) {
	return false;
	}
	streams->push_back(stream);
	return true;
	}

	bool ParseJingleRtpHeaderExtensions(const buzz::XmlElement* parent_elem,
	std::vector<RtpHeaderExtension>* hdrexts,
	ParseError* error) {
	for (const buzz::XmlElement* hdrext_elem =
	parent_elem->FirstNamed(QN_JINGLE_RTP_HDREXT);
	hdrext_elem != NULL;
	hdrext_elem = hdrext_elem->NextNamed(QN_JINGLE_RTP_HDREXT)) {
	std::string uri = hdrext_elem->Attr(QN_URI);
	int id = GetXmlAttr(hdrext_elem, QN_ID, 0);
	if (id <= 0) {
	return BadParse("Invalid RTP header extension id.", error);
	}
	hdrexts->push_back(RtpHeaderExtension(uri, id));
	}
	return true;
	}

	bool HasJingleStreams(const buzz::XmlElement* desc_elem) {
	const buzz::XmlElement* streams_elem =
	desc_elem->FirstNamed(QN_JINGLE_DRAFT_STREAMS);
	return (streams_elem != NULL);
	}

	bool ParseJingleStreams(const buzz::XmlElement* desc_elem,
	std::vector<StreamParams>* streams,
	ParseError* error) {
	const buzz::XmlElement* streams_elem =
	desc_elem->FirstNamed(QN_JINGLE_DRAFT_STREAMS);
	if (streams_elem == NULL) {
	return BadParse("Missing streams element.", error);
	}
	for (const buzz::XmlElement* stream_elem =
	streams_elem->FirstNamed(QN_JINGLE_DRAFT_STREAM);
	stream_elem != NULL;
	stream_elem = stream_elem->NextNamed(QN_JINGLE_DRAFT_STREAM)) {
	if (!ParseJingleStream(stream_elem, streams, error)) {
	return false;
	}
	}
	return true;
	}

	void WriteSsrcs(const std::vector<uint32>& ssrcs,
	buzz::XmlElement* parent_elem) {
	for (std::vector<uint32>::const_iterator ssrc = ssrcs.begin();
	ssrc != ssrcs.end(); ++ssrc) {
	buzz::XmlElement* ssrc_elem =
	new buzz::XmlElement(QN_JINGLE_DRAFT_SSRC, false);
	SetXmlBody(ssrc_elem, *ssrc);

	parent_elem->AddElement(ssrc_elem);
	}
	}

	void WriteSsrcGroups(const std::vector<SsrcGroup>& groups,
	buzz::XmlElement* parent_elem) {
	for (std::vector<SsrcGroup>::const_iterator group = groups.begin();
	group != groups.end(); ++group) {
	buzz::XmlElement* group_elem =
	new buzz::XmlElement(QN_JINGLE_DRAFT_SSRC_GROUP, false);
	AddXmlAttrIfNonEmpty(group_elem, QN_SEMANTICS, group->semantics);
	WriteSsrcs(group->ssrcs, group_elem);

	parent_elem->AddElement(group_elem);
	}
	}

	void WriteJingleStream(const StreamParams& stream,
	buzz::XmlElement* parent_elem) {
	buzz::XmlElement* stream_elem =
	new buzz::XmlElement(QN_JINGLE_DRAFT_STREAM, false);
	// We treat the nick as a stream groupid.
	AddXmlAttrIfNonEmpty(stream_elem, QN_NICK, stream.groupid);
	AddXmlAttrIfNonEmpty(stream_elem, QN_NAME, stream.id);
	AddXmlAttrIfNonEmpty(stream_elem, QN_TYPE, stream.type);
	AddXmlAttrIfNonEmpty(stream_elem, QN_DISPLAY, stream.display);
	AddXmlAttrIfNonEmpty(stream_elem, QN_CNAME, stream.cname);
	WriteSsrcs(stream.ssrcs, stream_elem);
	WriteSsrcGroups(stream.ssrc_groups, stream_elem);

	parent_elem->AddElement(stream_elem);
	}

	void WriteJingleStreams(const std::vector<StreamParams>& streams,
	buzz::XmlElement* parent_elem) {
	buzz::XmlElement* streams_elem =
	new buzz::XmlElement(QN_JINGLE_DRAFT_STREAMS, true);
	for (std::vector<StreamParams>::const_iterator stream = streams.begin();
	stream != streams.end(); ++stream) {
	WriteJingleStream(*stream, streams_elem);
	}

	parent_elem->AddElement(streams_elem);
	}

	void WriteJingleRtpHeaderExtensions(
	const std::vector<RtpHeaderExtension>& hdrexts,
	buzz::XmlElement* parent_elem) {
	for (std::vector<RtpHeaderExtension>::const_iterator hdrext = hdrexts.begin();
	hdrext != hdrexts.end(); ++hdrext) {
	buzz::XmlElement* hdrext_elem =
	new buzz::XmlElement(QN_JINGLE_RTP_HDREXT, false);
	AddXmlAttr(hdrext_elem, QN_URI, hdrext->uri);
	AddXmlAttr(hdrext_elem, QN_ID, hdrext->id);
	parent_elem->AddElement(hdrext_elem);
	}
	}


	} // namespace cricket