transmission/libtransmission/peer-mgr-active-requests.cc

235 lines
5.2 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 <ctime>
#include <memory>
#include <utility>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#define LIBTRANSMISSION_PEER_MODULE
#include "peer-mgr-active-requests.h"
#include "tr-assert.h"
namespace
{
struct peer_at
{
tr_peer* peer;
time_t when;
peer_at(tr_peer* p, time_t w)
: peer{ p }
, when{ w }
{
}
[[nodiscard]] int compare(peer_at const& that) const // <=>
{
if (peer != that.peer)
{
return peer < that.peer ? -1 : 1;
}
return 0;
}
bool operator==(peer_at const& that) const
{
return compare(that) == 0;
}
};
struct PeerAtHash
{
std::size_t operator()(peer_at const& pa) const noexcept
{
return std::hash<tr_peer*>{}(pa.peer);
}
};
} // namespace
class ActiveRequests::Impl
{
public:
size_t size() const
{
return size_;
}
size_t count(tr_peer const* peer) const
{
auto const it = count_.find(peer);
return it != std::end(count_) ? it->second : size_t{};
}
void incCount(tr_peer const* peer)
{
++count_[peer];
++size_;
}
void decCount(tr_peer const* peer)
{
auto it = count_.find(peer);
TR_ASSERT(it != std::end(count_));
TR_ASSERT(it->second > 0);
TR_ASSERT(size_ > 0);
if (it != std::end(count_))
{
if (--it->second == 0)
{
count_.erase(it);
}
--size_;
}
}
std::unordered_map<tr_peer const*, size_t> count_;
std::unordered_map<tr_block_index_t, std::unordered_set<peer_at, PeerAtHash>> blocks_;
private:
size_t size_ = 0;
};
ActiveRequests::ActiveRequests()
: impl_{ std::make_unique<Impl>() }
{
}
ActiveRequests::~ActiveRequests() = default;
bool ActiveRequests::add(tr_block_index_t block, tr_peer* peer, time_t when)
{
bool const added = impl_->blocks_[block].emplace(peer, when).second;
if (added)
{
impl_->incCount(peer);
}
return added;
}
// remove a request to `peer` for `block`
bool ActiveRequests::remove(tr_block_index_t block, tr_peer const* peer)
{
auto const it = impl_->blocks_.find(block);
auto const key = peer_at{ const_cast<tr_peer*>(peer), 0 };
auto const removed = it != std::end(impl_->blocks_) && it->second.erase(key) != 0;
if (removed)
{
impl_->decCount(peer);
if (std::empty(it->second))
{
impl_->blocks_.erase(it);
}
}
return removed;
}
// remove requests to `peer` and return the associated blocks
std::vector<tr_block_index_t> ActiveRequests::remove(tr_peer const* peer)
{
auto removed = std::vector<tr_block_index_t>{};
removed.reserve(impl_->blocks_.size());
auto const key = peer_at{ const_cast<tr_peer*>(peer), 0 };
for (auto const& [block, peers_at] : impl_->blocks_)
{
if (peers_at.count(key) != 0U)
{
removed.push_back(block);
}
}
for (auto block : removed)
{
remove(block, peer);
}
return removed;
}
// remove requests for `block` and return the associated peers
std::vector<tr_peer*> ActiveRequests::remove(tr_block_index_t block)
{
auto removed = std::vector<tr_peer*>{};
if (auto it = impl_->blocks_.find(block); it != std::end(impl_->blocks_))
{
auto const n = std::size(it->second);
removed.resize(n);
std::transform(
std::begin(it->second),
std::end(it->second),
std::begin(removed),
[](auto const& sent) { return sent.peer; });
impl_->blocks_.erase(block);
}
for (auto const* const peer : removed)
{
impl_->decCount(peer);
}
return removed;
}
// return true if there's an active request to `peer` for `block`
bool ActiveRequests::has(tr_block_index_t block, tr_peer const* peer) const
{
auto const it = impl_->blocks_.find(block);
return it != std::end(impl_->blocks_) && (it->second.count(peer_at{ const_cast<tr_peer*>(peer), 0 }) != 0U);
}
// count how many peers we're asking for `block`
size_t ActiveRequests::count(tr_block_index_t block) const
{
return std::size(impl_->blocks_[block]);
}
// count how many active block requests we have to `peer`
size_t ActiveRequests::count(tr_peer const* peer) const
{
return impl_->count(peer);
}
// return the total number of active requests
size_t ActiveRequests::size() const
{
return impl_->size();
}
// returns the active requests sent before `when`
std::vector<std::pair<tr_block_index_t, tr_peer*>> ActiveRequests::sentBefore(time_t when) const
{
auto sent_before = std::vector<std::pair<tr_block_index_t, tr_peer*>>{};
sent_before.reserve(std::size(impl_->blocks_));
for (auto const& [block, peers_at] : impl_->blocks_)
{
for (auto const& sent : peers_at)
{
if (sent.when < when)
{
sent_before.emplace_back(block, sent.peer);
}
}
}
return sent_before;
}