transmission/libtransmission/announce-list.cc

341 lines
9.3 KiB
C++

// This file Copyright © 2021-2023 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <algorithm>
#include <string>
#include <string_view>
#include <fmt/core.h>
#include "libtransmission/transmission.h"
#include "libtransmission/announce-list.h"
#include "libtransmission/quark.h"
#include "libtransmission/torrent-metainfo.h"
#include "libtransmission/utils.h"
#include "libtransmission/variant.h"
#include "libtransmission/web-utils.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(announce_urls[i], tiers[i]);
}
return size();
}
bool tr_announce_list::remove(std::string_view announce_url)
{
auto const 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)
{
if (auto const announce = tr_urlParseTracker(announce_url_sv); !announce || !can_add(*announce))
{
return false;
}
auto it = find(id);
if (it == std::end(trackers_))
{
return false;
}
auto const tier = it->tier;
trackers_.erase(it);
return add(announce_url_sv, tier);
}
bool tr_announce_list::add(std::string_view announce_url_sv, tr_tracker_tier_t tier)
{
auto const announce = tr_urlParseTracker(announce_url_sv);
if (!announce || !can_add(*announce))
{
return false;
}
auto tracker = tracker_info{};
tracker.announce = announce_url_sv;
tracker.tier = get_tier(tier, *announce);
tracker.id = next_unique_id();
tracker.host_and_port = fmt::format(FMT_STRING("{:s}:{:d}"), announce->host, announce->port);
tracker.sitename = announce->sitename;
if (auto const scrape_str = announce_to_scrape(announce_url_sv); scrape_str)
{
tracker.scrape = *scrape_str;
}
auto const it = std::lower_bound(std::begin(trackers_), std::end(trackers_), tracker);
trackers_.insert(it, tracker);
return true;
}
void tr_announce_list::add(tr_announce_list const& src)
{
if (std::empty(src))
{
return;
}
auto src_tier = src.at(0).tier;
auto& tgt = *this;
auto tgt_tier = tgt.nextTier();
for (auto const& tracker : src)
{
if (src_tier != tracker.tier)
{
src_tier = tracker.tier;
++tgt_tier;
}
tgt.add(tracker.announce.sv(), tgt_tier);
}
}
std::optional<std::string> tr_announce_list::announce_to_scrape(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 = "/announce"sv;
auto constexpr Newval = "/scrape"sv;
if (auto pos = announce.rfind(Oldval.front()); pos != std::string_view::npos && announce.find(Oldval, pos) == pos)
{
return std::string{ announce }.replace(pos, std::size(Oldval), Newval);
}
// some torrents with UDP announce URLs don't have /announce
if (tr_strv_starts_with(announce, "udp:"sv))
{
return std::string{ announce };
}
return {};
}
tr_quark tr_announce_list::announce_to_scrape(tr_quark announce)
{
if (auto const scrape_str = announce_to_scrape(tr_quark_get_string_view(announce)); scrape_str)
{
return tr_quark_new(*scrape_str);
}
return TR_KEY_NONE;
}
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::next_unique_id()
{
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.sv();
};
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::get_tier(tr_tracker_tier_t tier, tr_url_parsed_t const& announce) const
{
auto const is_sibling = [&announce](auto const& tracker)
{
auto const tracker_announce = tracker.announce.sv();
// fast test to avoid tr_urlParse()ing most trackers
if (!tr_strv_contains(tracker_announce, announce.host))
{
return false;
}
auto const candidate = tr_urlParse(tracker_announce);
return candidate->host == announce.host && candidate->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::can_add(tr_url_parsed_t const& announce) const noexcept
{
// 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)
{
auto const tracker_announce = tracker.announce.sv();
// fast test to avoid tr_urlParse()ing most trackers
if (!tr_strv_contains(tracker_announce, announce.host))
{
return false;
}
auto const tracker_parsed = tr_urlParse(tracker_announce);
return tracker_parsed->scheme == announce.scheme && tracker_parsed->host == announce.host &&
tracker_parsed->port == announce.port && tracker_parsed->path == announce.path;
};
return std::none_of(std::begin(trackers_), std::end(trackers_), is_same);
}
bool tr_announce_list::save(std::string_view torrent_file, tr_error** error) const
{
// load the torrent file
auto metainfo = tr_variant{};
if (!tr_variantFromFile(&metainfo, TR_VARIANT_PARSE_BENC, 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.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.quark());
}
}
// confirm that it's good by parsing it back again
auto const contents = tr_variantToStr(&metainfo, TR_VARIANT_FMT_BENC);
tr_variantClear(&metainfo);
if (auto tm = tr_torrent_metainfo{}; !tm.parse_benc(contents, error))
{
return false;
}
// save it
return tr_file_save(torrent_file, contents, error);
}
bool tr_announce_list::parse(std::string_view text)
{
auto scratch = tr_announce_list{};
auto current_tier = tr_tracker_tier_t{ 0 };
auto current_tier_size = size_t{ 0 };
auto line = std::string_view{};
while (tr_strv_sep(&text, &line, '\n'))
{
if (tr_strv_ends_with(line, '\r'))
{
line = line.substr(0, std::size(line) - 1);
}
line = tr_strv_strip(line);
if (std::empty(line))
{
if (current_tier_size > 0)
{
++current_tier;
current_tier_size = 0;
}
}
else if (scratch.add(line, current_tier))
{
++current_tier_size;
}
else
{
return false;
}
}
*this = scratch;
return true;
}
std::string tr_announce_list::to_string() const
{
auto text = std::string{};
auto current_tier = std::optional<tr_tracker_tier_t>{};
for (auto const& tracker : *this)
{
if (current_tier && *current_tier != tracker.tier)
{
text += '\n';
}
text += tracker.announce.sv();
text += '\n';
current_tier = tracker.tier;
}
return text;
}