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transmission/libtransmission/verify.cc

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// This file Copyright © 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 <chrono>
#include <ctime>
#include <mutex>
#include <optional>
#include <thread>
#include <vector>
#include <fmt/core.h>
#include "libtransmission/transmission.h"
#include "libtransmission/completion.h"
#include "libtransmission/crypto-utils.h"
#include "libtransmission/file.h"
#include "libtransmission/verify.h"
using namespace std::chrono_literals;
namespace
{
auto constexpr SleepPerSecondDuringVerify = 100ms;
[[nodiscard]] auto current_time_secs()
{
return std::chrono::time_point_cast<std::chrono::seconds>(std::chrono::steady_clock::now());
}
} // namespace
void tr_verify_worker::verify_torrent(Mediator& verify_mediator, std::atomic<bool> const& abort_flag)
{
verify_mediator.on_verify_started();
tr_sys_file_t fd = TR_BAD_SYS_FILE;
uint64_t file_pos = 0U;
uint32_t piece_pos = 0U;
tr_file_index_t file_index = 0U;
tr_file_index_t prev_file_index = ~file_index;
tr_piece_index_t piece = 0U;
auto buffer = std::vector<std::byte>(1024U * 256U);
auto sha = tr_sha1::create();
auto last_slept_at = current_time_secs();
auto const& metainfo = verify_mediator.metainfo();
while (!abort_flag && piece < metainfo.piece_count())
{
auto const file_length = metainfo.file_size(file_index);
/* if we're starting a new file... */
if (file_pos == 0 && fd == TR_BAD_SYS_FILE && file_index != prev_file_index)
{
auto const found = verify_mediator.find_file(file_index);
fd = !found ? TR_BAD_SYS_FILE : tr_sys_file_open(found->c_str(), TR_SYS_FILE_READ | TR_SYS_FILE_SEQUENTIAL, 0);
prev_file_index = file_index;
}
/* figure out how much we can read this pass */
uint64_t left_in_piece = metainfo.piece_size(piece) - piece_pos;
uint64_t left_in_file = file_length - file_pos;
uint64_t bytes_this_pass = std::min(left_in_file, left_in_piece);
bytes_this_pass = std::min(bytes_this_pass, uint64_t(std::size(buffer)));
/* read a bit */
if (fd != TR_BAD_SYS_FILE)
{
auto num_read = uint64_t{};
if (tr_sys_file_read_at(fd, std::data(buffer), bytes_this_pass, file_pos, &num_read) && num_read > 0)
{
bytes_this_pass = num_read;
sha->add(std::data(buffer), bytes_this_pass);
tr_sys_file_advise(fd, file_pos, bytes_this_pass, TR_SYS_FILE_ADVICE_DONT_NEED);
}
}
/* move our offsets */
left_in_piece -= bytes_this_pass;
left_in_file -= bytes_this_pass;
piece_pos += bytes_this_pass;
file_pos += bytes_this_pass;
/* if we're finishing a piece... */
if (left_in_piece == 0)
{
auto const has_piece = sha->finish() == metainfo.piece_hash(piece);
verify_mediator.on_piece_checked(piece, has_piece);
/* sleeping even just a few msec per second goes a long
* way towards reducing IO load... */
if (auto const now = current_time_secs(); last_slept_at != now)
{
last_slept_at = now;
std::this_thread::sleep_for(SleepPerSecondDuringVerify);
}
sha->clear();
++piece;
piece_pos = 0;
}
/* if we're finishing a file... */
if (left_in_file == 0)
{
if (fd != TR_BAD_SYS_FILE)
{
tr_sys_file_close(fd);
fd = TR_BAD_SYS_FILE;
}
++file_index;
file_pos = 0;
}
}
/* cleanup */
if (fd != TR_BAD_SYS_FILE)
{
tr_sys_file_close(fd);
}
verify_mediator.on_verify_done(abort_flag);
}
void tr_verify_worker::verify_thread_func()
{
for (;;)
{
{
auto const lock = std::lock_guard{ verify_mutex_ };
if (stop_current_)
{
stop_current_ = false;
stop_current_cv_.notify_one();
}
if (std::empty(todo_))
{
current_node_.reset();
verify_thread_id_.reset();
return;
}
current_node_ = std::move(todo_.extract(std::begin(todo_)).value());
}
verify_torrent(*current_node_->mediator_, stop_current_);
}
}
void tr_verify_worker::add(std::unique_ptr<Mediator> mediator, tr_priority_t priority)
{
auto const lock = std::lock_guard{ verify_mutex_ };
mediator->on_verify_queued();
todo_.emplace(std::move(mediator), priority);
if (!verify_thread_id_)
{
auto thread = std::thread(&tr_verify_worker::verify_thread_func, this);
verify_thread_id_ = thread.get_id();
thread.detach();
}
}
void tr_verify_worker::remove(tr_sha1_digest_t const& info_hash)
{
auto lock = std::unique_lock(verify_mutex_);
if (current_node_ && current_node_->matches(info_hash))
{
stop_current_ = true;
stop_current_cv_.wait(lock, [this]() { return !stop_current_; });
}
else if (auto const iter = std::find_if(
std::begin(todo_),
std::end(todo_),
[&info_hash](auto const& node) { return node.matches(info_hash); });
iter != std::end(todo_))
{
iter->mediator_->on_verify_done(true /*aborted*/);
todo_.erase(iter);
}
}
tr_verify_worker::~tr_verify_worker()
{
{
auto const lock = std::lock_guard{ verify_mutex_ };
stop_current_ = true;
todo_.clear();
}
while (verify_thread_id_.has_value())
{
std::this_thread::sleep_for(20ms);
}
}
int tr_verify_worker::Node::compare(Node const& that) const noexcept
{
// prefer higher-priority torrents
if (priority_ != that.priority_)
{
return priority_ > that.priority_ ? -1 : 1;
}
// prefer smaller torrents, since they will verify faster
auto const& metainfo = mediator_->metainfo();
auto const& that_metainfo = that.mediator_->metainfo();
if (metainfo.total_size() != that_metainfo.total_size())
{
return metainfo.total_size() < that_metainfo.total_size() ? -1 : 1;
}
// uniqueness check
auto const& this_hash = metainfo.info_hash();
auto const& that_hash = that_metainfo.info_hash();
if (this_hash != that_hash)
{
return this_hash < that_hash ? -1 : 1;
}
return 0;
}