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// Copyright (C) 2021-2022 Joel Rosdahl and other contributors
//
// See doc/AUTHORS.adoc for a complete list of contributors.
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program; if not, write to the Free Software Foundation, Inc., 51
// Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#include "StatsFile.hpp"
#include <AtomicFile.hpp>
#include <Logging.hpp>
#include <core/exceptions.hpp>
#include <fmtmacros.hpp>
#include <util/LockFile.hpp>
#include <util/file.hpp>
namespace storage::local {
StatsFile::StatsFile(const std::string& path) : m_path(path)
{
}
core::StatisticsCounters
StatsFile::read() const
{
core::StatisticsCounters counters;
const auto data = util::read_file<std::string>(m_path);
if (!data) {
// A nonexistent stats file is OK.
return counters;
}
size_t i = 0;
const char* str = data->c_str();
while (true) {
char* end;
const uint64_t value = std::strtoull(str, &end, 10);
if (end == str) {
break;
}
counters.set_raw(i, value);
++i;
str = end;
}
return counters;
}
std::optional<core::StatisticsCounters>
StatsFile::update(
std::function<void(core::StatisticsCounters& counters)> function) const
{
util::ShortLivedLockFile lock_file(m_path);
util::LockFileGuard lock(lock_file);
if (!lock.acquired()) {
LOG("Failed to acquire lock for {}", m_path);
return std::nullopt;
}
auto counters = read();
function(counters);
AtomicFile file(m_path, AtomicFile::Mode::text);
for (size_t i = 0; i < counters.size(); ++i) {
file.write(FMT("{}\n", counters.get_raw(i)));
}
try {
file.commit();
} catch (const core::Error& e) {
// Make failure to write a stats file a soft error since it's not important
// enough to fail whole the process and also because it is called in the
// Context destructor.
LOG("Error: {}", e.what());
}
return counters;
}
} // namespace storage::local
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