text: /*
  
  Copyright (c) 2007-2016, Arvid Norberg
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
      * 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.
      * Neither the name of the author nor the names of its
        contributors may be used to endorse or promote products derived
        from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
  
  */
  
  #include "libtorrent/magnet_uri.hpp"
  #include "libtorrent/session.hpp"
  #include "libtorrent/aux_/escape_string.hpp"
  #include "libtorrent/torrent_status.hpp"
  #include "libtorrent/torrent_info.hpp"
  #include "libtorrent/announce_entry.hpp"
  #include "libtorrent/hex.hpp" // to_hex, from_hex
  #include "libtorrent/socket_io.hpp"
  
  namespace libtorrent
  {
  	std::string make_magnet_uri(torrent_handle const& handle)
  	{
  		if (!handle.is_valid()) return "";
  
  		std::string ret;
  		sha1_hash const& ih = handle.info_hash();
  		ret += "magnet:?xt=urn:btih:";
  		ret += aux::to_hex(ih);
  
  		torrent_status st = handle.status(torrent_handle::query_name);
  		if (!st.name.empty())
  		{
  			ret += "&dn=";
  			ret += escape_string(st.name);
  		}
  
  		for (auto const& tr : handle.trackers())
  		{
  			ret += "&tr=";
  			ret += escape_string(tr.url);
  		}
  
  		for (auto const& s : handle.url_seeds())
  		{
  			ret += "&ws=";
  			ret += escape_string(s);
  		}
  
  		return ret;
  	}
  
  	std::string make_magnet_uri(torrent_info const& info)
  	{
  		std::string ret;
  		sha1_hash const& ih = info.info_hash();
  		ret += "magnet:?xt=urn:btih:";
  		ret += aux::to_hex(ih);
  
  		std::string const& name = info.name();
  
  		if (!name.empty())
  		{
  			ret += "&dn=";
  			ret += escape_string(name);
  		}
  
  		for (auto const& tr : info.trackers())
  		{
  			ret += "&tr=";
  			ret += escape_string(tr.url);
  		}
  
  		for (auto const& s : info.web_seeds())
  		{
  			if (s.type != web_seed_entry::url_seed) continue;
  
  			ret += "&ws=";
  			ret += escape_string(s.url);
  		}
  
  		return ret;
  	}
  
  #ifndef TORRENT_NO_DEPRECATE
  
  	namespace {
  		torrent_handle add_magnet_uri_deprecated(session& ses, std::string const& uri
  			, add_torrent_params p, error_code& ec)
  		{
  			parse_magnet_uri(uri, p, ec);
  			if (ec) return torrent_handle();
  			return ses.add_torrent(p, ec);
  		}
  	}
  
  	torrent_handle add_magnet_uri(session& ses, std::string const& uri
  		, add_torrent_params const& p, error_code& ec)
  	{
  		return add_magnet_uri_deprecated(ses, uri, p, ec);
  	}
  
  #ifndef BOOST_NO_EXCEPTIONS
  	torrent_handle add_magnet_uri(session& ses, std::string const& uri
  		, std::string const& save_path
  		, storage_mode_t storage_mode
  		, bool paused
  		, storage_constructor_type sc
  		, void* userdata)
  	{
  		add_torrent_params params(sc);
  		params.storage_mode = storage_mode;
  		params.userdata = userdata;
  		params.save_path = save_path;
  
  		if (paused) params.flags |= add_torrent_params::flag_paused;
  		else params.flags &= ~add_torrent_params::flag_paused;
  
  		error_code ec;
  		std::string display_name = url_has_argument(uri, "dn");
  		if (!display_name.empty()) params.name = unescape_string(display_name.c_str(), ec);
  		std::string tracker_string = url_has_argument(uri, "tr");
  		if (!tracker_string.empty()) params.trackers.push_back(unescape_string(tracker_string.c_str(), ec));
  
  		std::string btih = url_has_argument(uri, "xt");
  		if (btih.empty()) return torrent_handle();
  
  		if (btih.compare(0, 9, "urn:btih:") != 0) return torrent_handle();
  
  		if (btih.size() == 40 + 9) aux::from_hex({&btih[9], 40}, params.info_hash.data());
  		else params.info_hash.assign(base32decode(btih.substr(9)).c_str());
  
  		return ses.add_torrent(params);
  	}
  
  	torrent_handle add_magnet_uri(session& ses, std::string const& uri
  		, add_torrent_params const& p)
  	{
  		error_code ec;
  		torrent_handle ret = add_magnet_uri_deprecated(ses, uri, p, ec);
  		if (ec) throw system_error(ec);
  		return ret;
  	}
  #endif // BOOST_NO_EXCEPTIONS
  #endif // TORRENT_NO_DEPRECATE
  
  	// TODO: 3 take string_ref here instead
  	void parse_magnet_uri(std::string const& uri, add_torrent_params& p, error_code& ec)
  	{
  		ec.clear();
  		std::string name;
  
  		{
  			error_code e;
  			std::string display_name = url_has_argument(uri, "dn");
  			if (!display_name.empty()) name = unescape_string(display_name.c_str(), e);
  		}
  
  		// parse trackers out of the magnet link
  		std::string::size_type pos = std::string::npos;
  		std::string url = url_has_argument(uri, "tr", &pos);
  		int tier = 0;
  		while (pos != std::string::npos)
  		{
  			// since we're about to assign tiers to the trackers, make sure the two
  			// vectors are aligned
  			if (p.tracker_tiers.size() != p.trackers.size())
  				p.tracker_tiers.resize(p.trackers.size(), 0);
  
  			error_code e;
  			url = unescape_string(url, e);
  			if (e) continue;
  			p.trackers.push_back(url);
  			p.tracker_tiers.push_back(tier++);
  			pos = uri.find("&tr=", pos);
  			if (pos == std::string::npos) break;
  			pos += 4;
  			url = uri.substr(pos, uri.find('&', pos) - pos);
  		}
  
  		// parse web seeds out of the magnet link
  		pos = std::string::npos;
  		url = url_has_argument(uri, "ws", &pos);
  		while (pos != std::string::npos)
  		{
  			error_code e;
  			url = unescape_string(url, e);
  			if (e) continue;
  			p.url_seeds.push_back(url);
  			pos = uri.find("&ws=", pos);
  			if (pos == std::string::npos) break;
  			pos += 4;
  			url = uri.substr(pos, uri.find('&', pos) - pos);
  		}
  
  		std::string btih = url_has_argument(uri, "xt");
  		if (btih.empty())
  		{
  			ec = errors::missing_info_hash_in_uri;
  			return;
  		}
  
  		if (btih.compare(0, 9, "urn:btih:") != 0)
  		{
  			ec = errors::missing_info_hash_in_uri;
  			return;
  		}
  
  		std::string::size_type peer_pos = std::string::npos;
  		std::string peer = url_has_argument(uri, "x.pe", &peer_pos);
  		while (!peer.empty())
  		{
  			error_code e;
  			tcp::endpoint endp = parse_endpoint(peer, e);
  			if (!e)
  				p.peers.push_back(endp);
  
  			peer_pos = uri.find("&x.pe=", peer_pos);
  			if (peer_pos == std::string::npos) break;
  			peer_pos += 6;
  			peer = uri.substr(peer_pos, uri.find('&', peer_pos) - peer_pos);
  		}
  
  #ifndef TORRENT_DISABLE_DHT
  		std::string::size_type node_pos = std::string::npos;
  		std::string node = url_has_argument(uri, "dht", &node_pos);
  		while (!node.empty())
  		{
  			std::string::size_type divider = node.find_last_of(':');
  			if (divider != std::string::npos)
  			{
  				int port = atoi(node.c_str() + divider + 1);
  				if (port != 0)
  					p.dht_nodes.push_back(std::make_pair(node.substr(0, divider), port));
  			}
  
  			node_pos = uri.find("&dht=", node_pos);
  			if (node_pos == std::string::npos) break;
  			node_pos += 5;
  			node = uri.substr(node_pos, uri.find('&', node_pos) - node_pos);
  		}
  #endif
  
  		sha1_hash info_hash;
  		if (btih.size() == 40 + 9) aux::from_hex({&btih[9], 40}, info_hash.data());
  		else if (btih.size() == 32 + 9)
  		{
  			std::string ih = base32decode(btih.substr(9));
  			if (ih.size() != 20)
  			{
  				ec = errors::invalid_info_hash;
  				return;
  			}
  			info_hash.assign(ih);
  		}
  		else
  		{
  			ec = errors::invalid_info_hash;
  			return;
  		}
  
  		p.info_hash = info_hash;
  		if (!name.empty()) p.name = name;
  	}
  }
  