transmission/libtransmission/announce-list.cc

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/*
* This file Copyright (C) Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#include <algorithm>
#include <set>
#include <string>
#include <string_view>
#include "transmission.h"
#include "announce-list.h"
#include "quark.h"
#include "torrent-metainfo.h"
#include "utils.h"
#include "variant.h"
using namespace std::literals;
size_t tr_announce_list::set(char const* const* announce_urls, tr_tracker_tier_t const* tiers, size_t n)
{
trackers_.clear();
for (size_t i = 0; i < n; ++i)
{
add(tiers[i], announce_urls[i]);
}
return size();
}
bool tr_announce_list::remove(std::string_view announce_url)
{
auto it = find(announce_url);
if (it == std::end(trackers_))
{
return false;
}
trackers_.erase(it);
return true;
}
bool tr_announce_list::remove(tr_tracker_id_t id)
{
auto it = find(id);
if (it == std::end(trackers_))
{
return false;
}
trackers_.erase(it);
return true;
}
bool tr_announce_list::replace(tr_tracker_id_t id, std::string_view announce_url_sv)
{
auto const announce = tr_urlParseTracker(announce_url_sv);
if (!announce || !canAdd(*announce))
{
return false;
}
auto it = find(id);
if (it == std::end(trackers_))
{
return false;
}
auto const tier = it->tier;
trackers_.erase(it);
return add(tier, announce_url_sv);
}
bool tr_announce_list::add(tr_tracker_tier_t tier, std::string_view announce_url_sv)
{
auto const announce = tr_urlParseTracker(announce_url_sv);
if (!announce || !canAdd(*announce))
{
return false;
}
auto tracker = tracker_info{};
tracker.announce_str = announce_url_sv;
tracker.announce = *tr_urlParseTracker(tracker.announce_str.sv());
tracker.tier = getTier(tier, *announce);
tracker.id = nextUniqueId();
tracker.host = tr_strvJoin(tracker.announce.host, ":"sv, tracker.announce.portstr);
auto const scrape_str = announceToScrape(announce_url_sv);
if (scrape_str)
{
tracker.scrape_str = *scrape_str;
tracker.scrape = *tr_urlParseTracker(tracker.scrape_str.sv());
}
auto const it = std::lower_bound(std::begin(trackers_), std::end(trackers_), tracker);
trackers_.insert(it, tracker);
return true;
}
std::optional<std::string> tr_announce_list::announceToScrape(std::string_view announce)
{
// To derive the scrape URL use the following steps:
// Begin with the announce URL. Find the last '/' in it.
// If the text immediately following that '/' isn't 'announce'
// it will be taken as a sign that that tracker doesn't support
// the scrape convention. If it does, substitute 'scrape' for
// 'announce' to find the scrape page.
auto constexpr oldval = std::string_view{ "/announce" };
if (auto pos = announce.rfind(oldval.front()); pos != std::string_view::npos && announce.find(oldval, pos) == pos)
{
auto const prefix = announce.substr(0, pos);
auto const suffix = announce.substr(pos + std::size(oldval));
return tr_strvJoin(prefix, std::string_view{ "/scrape" }, suffix);
}
// some torrents with UDP announce URLs don't have /announce
if (tr_strvStartsWith(announce, std::string_view{ "udp:" }))
{
return std::string{ announce };
}
return {};
}
tr_quark tr_announce_list::announceToScrape(tr_quark announce)
{
auto const scrape_str = announceToScrape(tr_quark_get_string_view(announce));
if (scrape_str)
{
return tr_quark_new(*scrape_str);
}
return TR_KEY_NONE;
}
std::set<tr_tracker_tier_t> tr_announce_list::tiers() const
{
auto tiers = std::set<tr_tracker_tier_t>{};
for (auto const& tracker : trackers_)
{
tiers.insert(tracker.tier);
}
return tiers;
}
tr_tracker_tier_t tr_announce_list::nextTier() const
{
return std::empty(trackers_) ? 0 : trackers_.back().tier + 1;
}
tr_tracker_id_t tr_announce_list::nextUniqueId()
{
static tr_tracker_id_t id = 0;
return id++;
}
tr_announce_list::trackers_t::iterator tr_announce_list::find(tr_tracker_id_t id)
{
auto const test = [&id](auto const& tracker)
{
return tracker.id == id;
};
return std::find_if(std::begin(trackers_), std::end(trackers_), test);
}
tr_announce_list::trackers_t::iterator tr_announce_list::find(std::string_view announce)
{
auto const test = [&announce](auto const& tracker)
{
return announce == tracker.announce.full;
};
return std::find_if(std::begin(trackers_), std::end(trackers_), test);
}
// if two announce URLs differ only by scheme, put them in the same tier.
// (note: this can leave gaps in the `tier' values, but since the calling
// function doesn't care, there's no point in removing the gaps...)
tr_tracker_tier_t tr_announce_list::getTier(tr_tracker_tier_t tier, tr_url_parsed_t const& announce) const
{
auto const is_sibling = [&announce](tracker_info const& tracker)
{
return tracker.announce.host == announce.host && tracker.announce.path == announce.path;
};
auto const it = std::find_if(std::begin(trackers_), std::end(trackers_), is_sibling);
return it != std::end(trackers_) ? it->tier : tier;
}
bool tr_announce_list::canAdd(tr_url_parsed_t const& announce)
{
// looking at components instead of the full original URL lets
// us weed out implicit-vs-explicit port duplicates e.g.
// "http://tracker/announce" + "http://tracker:80/announce"
auto const is_same = [&announce](auto const& tracker)
{
return tracker.announce.scheme == announce.scheme && tracker.announce.host == announce.host &&
tracker.announce.port == announce.port && tracker.announce.path == announce.path;
};
return std::none_of(std::begin(trackers_), std::end(trackers_), is_same);
}
bool tr_announce_list::save(std::string const& torrent_file, tr_error** error) const
{
// load the .torrent file
auto metainfo = tr_variant{};
if (!tr_variantFromFile(&metainfo, TR_VARIANT_PARSE_BENC, std::string{ torrent_file }, error))
{
return false;
}
// remove the old fields
tr_variantDictRemove(&metainfo, TR_KEY_announce);
tr_variantDictRemove(&metainfo, TR_KEY_announce_list);
// add the new fields
if (this->size() == 1)
{
tr_variantDictAddQuark(&metainfo, TR_KEY_announce, at(0).announce_str.quark());
}
else if (this->size() > 1)
{
tr_variant* tier_list = tr_variantDictAddList(&metainfo, TR_KEY_announce_list, 0);
auto current_tier = std::optional<tr_tracker_tier_t>{};
tr_variant* tracker_list = nullptr;
for (auto const& tracker : *this)
{
if (tracker_list == nullptr || !current_tier || current_tier != tracker.tier)
{
tracker_list = tr_variantListAddList(tier_list, 1);
current_tier = tracker.tier;
}
tr_variantListAddQuark(tracker_list, tracker.announce_str.quark());
}
}
// confirm that it's good by parsing it back again
auto const contents = tr_variantToStr(&metainfo, TR_VARIANT_FMT_BENC);
tr_variantFree(&metainfo);
auto tm = tr_torrent_metainfo{};
if (!tm.parseBenc(contents))
{
return false;
}
// save it
return tr_saveFile(torrent_file, contents, error);
}