premiere-libtorrent/include/libtorrent/announce_entry.hpp

/*

Copyright (c) 2015-2016, Arvid Norberg
All rights reserved.

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modification, are permitted provided that the following conditions
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    * Redistributions of source code must retain the above copyright
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    * Redistributions in binary form must reproduce the above copyright
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      the documentation and/or other materials provided with the distribution.
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      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

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*/

#ifndef TORRENT_ANNOUNCE_ENTRY_HPP_INCLUDED
#define TORRENT_ANNOUNCE_ENTRY_HPP_INCLUDED

#include "libtorrent/config.hpp"
#include "libtorrent/time.hpp"
#include "libtorrent/error_code.hpp"

#include <string>
#include <cstdint>

namespace libtorrent
{
	// this class holds information about one bittorrent tracker, as it
	// relates to a specific torrent.
	struct TORRENT_EXPORT announce_entry
	{
		// constructs a tracker announce entry with ``u`` as the URL.
		announce_entry(std::string const& u);
		announce_entry();
		~announce_entry();
		announce_entry(announce_entry const&) = default;
		announce_entry& operator=(announce_entry const&) = default;

		// tracker URL as it appeared in the torrent file
		std::string url;

		// the current ``&trackerid=`` argument passed to the tracker.
		// this is optional and is normally empty (in which case no
		// trackerid is sent).
		std::string trackerid;

		// if this tracker has returned an error or warning message
		// that message is stored here
		std::string message;

		// if this tracker failed the last time it was contacted
		// this error code specifies what error occurred
		error_code last_error;

		// returns the number of seconds to the next announce on this tracker.
		// ``min_announce_in()`` returns the number of seconds until we are
		// allowed to force another tracker update with this tracker.
		// 
		// If the last time this tracker was contacted failed, ``last_error`` is
		// the error code describing what error occurred.
		int next_announce_in() const;
		int min_announce_in() const;

		// the time of next tracker announce
		time_point next_announce;

		// no announces before this time
		time_point min_announce;

		// TODO: include the number of peers received from this tracker, at last
		// announce

		// these are either -1 or the scrape information this tracker last
		// responded with. *incomplete* is the current number of downloaders in
		// the swarm, *complete* is the current number of seeds in the swarm and
		// *downloaded* is the cumulative number of completed downloads of this
		// torrent, since the beginning of time (from this tracker's point of
		// view).

		// if this tracker has returned scrape data, these fields are filled in
		// with valid numbers. Otherwise they are set to -1. the number of
		// current downloaders
		int scrape_incomplete;
		int scrape_complete;
		int scrape_downloaded;

		// the tier this tracker belongs to
		std::uint8_t tier;

		// the max number of failures to announce to this tracker in
		// a row, before this tracker is not used anymore. 0 means unlimited
		std::uint8_t fail_limit;

		// the number of times in a row we have failed to announce to this
		// tracker.
		std::uint8_t fails:7;

		// true while we're waiting for a response from the tracker.
		bool updating:1;

		// flags for the source bitmask, each indicating where
		// we heard about this tracker
		enum tracker_source
		{
			// the tracker was part of the .torrent file
			source_torrent = 1,
			// the tracker was added programatically via the add_troacker()_ function
			source_client = 2,
			// the tracker was part of a magnet link
			source_magnet_link = 4,
			// the tracker was received from the swarm via tracker exchange
			source_tex = 8
		};

		// a bitmask specifying which sources we got this tracker from.
		std::uint8_t source:4;

		// set to true the first time we receive a valid response
		// from this tracker.
		bool verified:1;

		// set to true when we get a valid response from an announce
		// with event=started. If it is set, we won't send start in the subsequent
		// announces.
		bool start_sent:1;

		// set to true when we send a event=completed.
		bool complete_sent:1;

		// this is false the stats sent to this tracker will be 0
		bool send_stats:1;

		// internal
		bool triggered_manually:1;

		// reset announce counters and clears the started sent flag.
		// The announce_entry will look like we've never talked to
		// the tracker.
		void reset();

		// updates the failure counter and time-outs for re-trying.
		// This is called when the tracker announce fails.
		void failed(time_duration tracker_backoff, int retry_interval = 0);

#ifndef TORRENT_NO_DEPRECATE
		// deprecated in 1.0
		TORRENT_DEPRECATED
		bool will_announce(time_point now) const
		{
			return now <= next_announce
				&& (fails < fail_limit || fail_limit == 0)
				&& !updating;
		}
#endif

		// returns true if we can announce to this tracker now.
		// The current time is passed in as ``now``. The ``is_seed``
		// argument is necessary because once we become a seed, we
		// need to announce right away, even if the re-announce timer
		// hasn't expired yet.
		bool can_announce(time_point now, bool is_seed) const;

		// returns true if the last time we tried to announce to this
		// tracker succeeded, or if we haven't tried yet.
		bool is_working() const
		{ return fails == 0; }

		// trims whitespace characters from the beginning of the URL.
		void trim();
	};

}

#endif