transmission/libtransmission/peer-mgr-wishlist.cc

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// 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 <cstddef>
#include <set>
#include <utility>
#include <vector>
#define LIBTRANSMISSION_PEER_MODULE
#include "libtransmission/transmission.h"
#include "libtransmission/crypto-utils.h" // for tr_salt_shaker
#include "libtransmission/peer-mgr-wishlist.h"
#include "libtransmission/tr-assert.h"
namespace
{
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using SaltType = tr_piece_index_t;
struct Candidate
{
tr_piece_index_t piece;
size_t n_blocks_missing;
tr_priority_t priority;
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SaltType salt;
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Candidate(tr_piece_index_t piece_in, size_t missing_in, tr_priority_t priority_in, SaltType salt_in)
: piece{ piece_in }
, n_blocks_missing{ missing_in }
, priority{ priority_in }
, salt{ salt_in }
{
}
[[nodiscard]] int compare(Candidate const& that) const // <=>
{
// prefer pieces closer to completion
if (n_blocks_missing != that.n_blocks_missing)
{
return n_blocks_missing < that.n_blocks_missing ? -1 : 1;
}
// prefer higher priority
if (priority != that.priority)
{
return priority > that.priority ? -1 : 1;
}
if (salt != that.salt)
{
return salt < that.salt ? -1 : 1;
}
return 0;
}
bool operator<(Candidate const& that) const // less than
{
return compare(that) < 0;
}
};
std::vector<Candidate> getCandidates(Wishlist::Mediator const& mediator)
{
// count up the pieces that we still want
auto wanted_pieces = std::vector<std::pair<tr_piece_index_t, size_t>>{};
auto const n_pieces = mediator.countAllPieces();
wanted_pieces.reserve(n_pieces);
for (tr_piece_index_t i = 0; i < n_pieces; ++i)
{
if (!mediator.clientCanRequestPiece(i))
{
continue;
}
size_t const n_missing = mediator.countMissingBlocks(i);
if (n_missing == 0)
{
continue;
}
wanted_pieces.emplace_back(i, n_missing);
}
// transform them into candidates
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auto salter = tr_salt_shaker<SaltType>{};
auto const n = std::size(wanted_pieces);
auto candidates = std::vector<Candidate>{};
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auto const is_sequential = mediator.isSequentialDownload();
candidates.reserve(n);
for (size_t i = 0; i < n; ++i)
{
auto const [piece, n_missing] = wanted_pieces[i];
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auto const salt = is_sequential ? piece : salter();
candidates.emplace_back(piece, n_missing, mediator.priority(piece), salt);
}
return candidates;
}
fix: sonarcloud warnings / code smells (#2242) * fix: use-init-statement Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX1f6EvHJiycnfA7gfrG\&open\=AX1f6EvHJiycnfA7gfrG * fix replace-use-of-new warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX1ZNs41ZmlvCveKTzon\&open\=AX1ZNs41ZmlvCveKTzon * fix has-virtual-functions-but-non-virtual-destructor warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX1ZNs72ZmlvCveKTzo6\&open\=AX1ZNs72ZmlvCveKTzo6 * fix make-variable-const warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX0_a_OVNJn7rAzml_7B\&open\=AX0_a_OVNJn7rAzml_7B * fix remove-redundant-static-specifiers Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06St-81usi2gyYkPTb\&open\=AX06St-81usi2gyYkPTb * fix function-should-be-declared-const Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06St-81usi2gyYkPTd\&open\=AX06St-81usi2gyYkPTd * fix use-init-statement warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06St-81usi2gyYkPTc\&open\=AX06St-81usi2gyYkPTc * fix class-has-virtual-functions-but-non-virtual-destructor warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06Stz41usi2gyYkPTS\&open\=AX06Stz41usi2gyYkPTS * fix remove-commented-out-code warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06St241usi2gyYkPTT\&open\=AX06St241usi2gyYkPTT * fix remove-commented-out-code warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06St241usi2gyYkPTV\&open\=AX06St241usi2gyYkPTV * fix has-virtual-functions-but-non-virtual-destructor warning https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06St241usi2gyYkPTW\&open\=AX06St241usi2gyYkPTW * fix remove-commented-out-code warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX06SuCA1usi2gyYkPTh\&open\=AX06SuCA1usi2gyYkPTh * fix use-init-statement warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX0rAQvnfJ-O-YIDS9xF\&open\=AX0rAQvnfJ-O-YIDS9xF * fix use-init-statement warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX0rAQvnfJ-O-YIDS9xG\&open\=AX0rAQvnfJ-O-YIDS9xG * fix remove-redundant-access-specifier warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX1ZNs5tZmlvCveKTzor\&open\=AX1ZNs5tZmlvCveKTzor * fix use-init-statement warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX01Itl7f_SST5i7BN1l\&open\=AX01Itl7f_SST5i7BN1l * fix use-init-statement warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX0wDijI2l89lDvp1C9P\&open\=AX0wDijI2l89lDvp1C9P * fix use-automatically-managed-memory-instead-of-new warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX1f6E6HJiycnfA7gfrI\&open\=AX1f6E6HJiycnfA7gfrI * fix use-init-statement warning Xref: https://sonarcloud.io/project/issues\?id\=transmission_transmission\&issues\=AX0l8vknEafnvRiIHUEv\&open\=AX0l8vknEafnvRiIHUEv * fixup! fix has-virtual-functions-but-non-virtual-destructor warning
2021-11-28 01:58:35 +00:00
std::vector<tr_block_span_t> makeSpans(tr_block_index_t const* sorted_blocks, size_t n_blocks)
{
if (n_blocks == 0)
{
return {};
}
auto spans = std::vector<tr_block_span_t>{};
auto cur = tr_block_span_t{ sorted_blocks[0], sorted_blocks[0] + 1 };
for (size_t i = 1; i < n_blocks; ++i)
{
if (cur.end == sorted_blocks[i])
{
++cur.end;
}
else
{
spans.push_back(cur);
cur = tr_block_span_t{ sorted_blocks[i], sorted_blocks[i] + 1 };
}
}
spans.push_back(cur);
return spans;
}
} // namespace
std::vector<tr_block_span_t> Wishlist::next(size_t n_wanted_blocks)
{
if (n_wanted_blocks == 0)
{
return {};
}
auto candidates = getCandidates(mediator_);
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// We usually won't need all the candidates to be sorted until endgame, so don't
// waste cycles sorting all of them here. partial sort is enough.
auto constexpr MaxSortedPieces = size_t{ 30 };
auto const middle = std::min(std::size(candidates), MaxSortedPieces);
std::partial_sort(std::begin(candidates), std::begin(candidates) + middle, std::end(candidates));
auto blocks = std::set<tr_block_index_t>{};
for (auto const& candidate : candidates)
{
// do we have enough?
if (std::size(blocks) >= n_wanted_blocks)
{
break;
}
// walk the blocks in this piece
auto const [begin, end] = mediator_.blockSpan(candidate.piece);
for (tr_block_index_t block = begin; block < end && std::size(blocks) < n_wanted_blocks; ++block)
{
// don't request blocks we've already got
if (!mediator_.clientCanRequestBlock(block))
{
continue;
}
// don't request from too many peers
size_t const n_peers = mediator_.countActiveRequests(block);
if (size_t const max_peers = mediator_.isEndgame() ? 2 : 1; n_peers >= max_peers)
{
continue;
}
blocks.insert(block);
}
}
auto const blocks_v = std::vector<tr_block_index_t>{ std::begin(blocks), std::end(blocks) };
return makeSpans(std::data(blocks_v), std::size(blocks_v));
}