libdatachannel/include/rtc/description.hpp

/**
 * Copyright (c) 2019-2020 Paul-Louis Ageneau
 * Copyright (c) 2020 Staz M
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef RTC_DESCRIPTION_H
#define RTC_DESCRIPTION_H

#include "candidate.hpp"
#include "include.hpp"

#include <iostream>
#include <map>
#include <memory>
#include <optional>
#include <variant>
#include <vector>

namespace rtc {

class Description {
public:
	enum class Type { Unspec = 0, Offer = 1, Answer = 2 };
	enum class Role { ActPass = 0, Passive = 1, Active = 2 };
	enum class Direction { SendOnly, RecvOnly, SendRecv, Inactive, Unknown };

	Description(const string &sdp, const string &typeString = "");
	Description(const string &sdp, Type type);
	Description(const string &sdp, Type type, Role role);

	Type type() const;
	string typeString() const;
	Role role() const;
	string roleString() const;
	string bundleMid() const;
	std::optional<string> fingerprint() const;
	bool ended() const;

	void hintType(Type type);
	void setFingerprint(string fingerprint);

	void addCandidate(Candidate candidate);
	void endCandidates();
	std::vector<Candidate> extractCandidates();

	operator string() const;
	string generateSdp(string_view eol) const;
	string generateApplicationSdp(string_view eol) const;

	class Entry {
	public:
		virtual ~Entry() = default;

		virtual string type() const { return mType; }
		virtual string description() const { return mDescription; }
		virtual string mid() const { return mMid; }
		Direction direction() const { return mDirection; }
		void setDirection(Direction dir);

		virtual void parseSdpLine(string_view line);
		virtual string generateSdp(string_view eol) const;

	protected:
		Entry(string mline, string mid = "", Direction dir = Direction::Unknown);

		std::vector<string> mAttributes;

	private:
		string mType;
		string mDescription;
		string mMid;
		Direction mDirection;
	};

	struct Application : public Entry {
	public:
		Application(string mid = "data");
		Application(const Application &other) = default;
		Application(Application &&other) = default;

		string description() const override;
		Application reciprocate() const;

		void setSctpPort(uint16_t port) { mSctpPort = port; }
		void hintSctpPort(uint16_t port) { mSctpPort = mSctpPort.value_or(port); }
		void setMaxMessageSize(size_t size) { mMaxMessageSize = size; }

		std::optional<uint16_t> sctpPort() const { return mSctpPort; }
		std::optional<size_t> maxMessageSize() const { return mMaxMessageSize; }

		virtual void parseSdpLine(string_view line) override;
		virtual string generateSdp(string_view eol) const override;

	private:
		std::optional<uint16_t> mSctpPort;
		std::optional<size_t> mMaxMessageSize;
	};

	// Media (non-data)
	class Media : public Entry {
	public:
		Media(string mline, string mid = "media", Direction dir = Direction::SendOnly);
		Media(const Media &other) = default;
		Media(Media &&other) = default;
		virtual ~Media() = default;

		string description() const override;
		Media reciprocate() const;

		void removeFormat(const string &fmt);

		void addVideoCodec(int payloadType, const string &codec);
		void addH264Codec(int payloadType);
		void addVP8Codec(int payloadType);
		void addVP9Codec(int payloadType);

		void setBitrate(int bitrate);
		int getBitrate() const;

		bool hasPayloadType(int payloadType) const;

		virtual void parseSdpLine(string_view line) override;
		virtual string generateSdp(string_view eol) const override;

	private:
		int mBas = -1;

		struct RTPMap {
			RTPMap(string_view mline);

			void removeFB(const string &string);
			void addFB(const string &string);

			int pt;
			string format;
			int clockRate;
			string encParams;

			std::vector<string> rtcpFbs;
			std::vector<string> fmtps;
		};

		Media::RTPMap &getFormat(int fmt);
		Media::RTPMap &getFormat(const string &fmt);

		std::map<int, RTPMap> mRtpMap;
	};

	class Audio : public Media {
	public:
		Audio(string mid = "audio", Direction dir = Direction::SendOnly);
	};

	class Video : public Media {
	public:
		Video(string mid = "video", Direction dir = Direction::SendOnly);
	};

	bool hasApplication() const;
	bool hasAudioOrVideo() const;

	int addMedia(Media media);
	int addMedia(Application application);
	int addApplication(string mid = "data");
	int addVideo(string mid = "video", Direction dir = Direction::SendOnly);
	int addAudio(string mid = "audio", Direction dir = Direction::SendOnly);

	std::variant<Media *, Application *> media(int index);
	std::variant<const Media *, const Application *> media(int index) const;
	int mediaCount() const;

	Application *application();

private:
	std::shared_ptr<Entry> createEntry(string mline, string mid, Direction dir);
	void removeApplication();

	Type mType;

	// Session-level attributes
	Role mRole;
	string mSessionId;
	string mIceUfrag, mIcePwd;
	std::optional<string> mFingerprint;

	// Entries
	std::vector<std::shared_ptr<Entry>> mEntries;
	std::shared_ptr<Application> mApplication;

	// Candidates
	std::vector<Candidate> mCandidates;
	bool mEnded = false;

	static Type stringToType(const string &typeString);
	static string typeToString(Type type);
	static string roleToString(Role role);
};

} // namespace rtc

std::ostream &operator<<(std::ostream &out, const rtc::Description &description);

#endif