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// Copyright (c) 2026 Progmasoft.
// SPDX-License-Identifier: MPL-2.0 WITH AdditionRef-Progmasoft-Exception-1.1
#include "Files.hpp"
#include "Hash.hpp"
#include "Process.hpp"
#if defined(_WIN32)
# include <fcntl.h>
# include <io.h>
# include <share.h>
# include <sys/stat.h>
#else
# include <fcntl.h>
# include <sys/stat.h>
# include <unistd.h>
#endif
#include <atomic>
#include <cstdio>
#include <fstream>
#include <sstream>
#include <system_error>
#include <thread>
namespace Progmasoft::Catch3::Runner
{
namespace
{
/// Creates `path` only if it does not exist, in one atomic step.
bool
CreateExclusively(const std::filesystem::path &path)
{
#if defined(_WIN32)
int descriptor = -1;
if (_wsopen_s(&descriptor,
path.wstring().c_str(),
_O_CREAT | _O_EXCL | _O_WRONLY,
_SH_DENYNO,
_S_IREAD | _S_IWRITE) != 0)
{
return false;
}
_close(descriptor);
return true;
#else
const int descriptor = open(path.c_str(),
O_CREAT | O_EXCL | O_WRONLY | O_CLOEXEC,
S_IRUSR | S_IWUSR);
if (descriptor < 0)
{
return false;
}
close(descriptor);
return true;
#endif
}
} // namespace
FileLock::FileLock(const std::filesystem::path &file,
std::chrono::milliseconds wait,
std::chrono::milliseconds stale)
: path_{file.string() + ".lock"}
{
std::error_code error;
std::filesystem::create_directories(path_.parent_path(), error);
const auto deadline = std::chrono::steady_clock::now() + wait;
while (true)
{
if (CreateExclusively(path_))
{
held_ = true;
return;
}
const auto written = std::filesystem::last_write_time(path_, error);
if (!error &&
std::filesystem::file_time_type::clock::now() - written > stale)
{
std::filesystem::remove(path_, error);
continue;
}
if (std::chrono::steady_clock::now() >= deadline)
{
return;
}
std::this_thread::sleep_for(std::chrono::milliseconds(10));
}
}
FileLock::~FileLock()
{
if (held_)
{
std::error_code error;
std::filesystem::remove(path_, error);
}
}
Expected<std::string>
ReadFile(const std::filesystem::path &file)
{
std::ifstream input(file, std::ios::binary);
if (!input)
{
return Error{"cannot read '" + file.string() + "'"};
}
std::ostringstream contents;
contents << input.rdbuf();
if (input.bad())
{
return Error{"cannot read '" + file.string() + "'"};
}
return contents.str();
}
Status
WriteFileAtomically(const std::filesystem::path &file,
std::string_view contents)
{
std::error_code error;
if (file.has_parent_path())
{
std::filesystem::create_directories(file.parent_path(), error);
}
const auto temporary =
std::filesystem::path{file.string() + "." + UniqueName() + ".tmp"};
{
std::ofstream output(temporary, std::ios::binary | std::ios::trunc);
output.write(contents.data(),
static_cast<std::streamsize>(contents.size()));
if (!output)
{
output.close();
std::filesystem::remove(temporary, error);
return Error{"cannot write '" + file.string() + "'"};
}
}
std::filesystem::rename(temporary, file, error);
if (error)
{
std::error_code ignored;
std::filesystem::remove(temporary, ignored);
return Error{"cannot replace '" + file.string() +
"': " + error.message()};
}
return Status::Ok();
}
Status
CreatePrivateFile(const std::filesystem::path &file)
{
#if defined(_WIN32)
std::error_code error;
const auto status = std::filesystem::symlink_status(file, error);
if (!error && std::filesystem::exists(status) &&
!std::filesystem::is_regular_file(status))
{
return Error{"'" + file.string() + "' is not a regular file"};
}
int descriptor = -1;
if (_wsopen_s(&descriptor,
file.wstring().c_str(),
_O_CREAT | _O_TRUNC | _O_WRONLY | _O_NOINHERIT,
_SH_DENYNO,
_S_IREAD | _S_IWRITE) != 0)
{
return Error{"cannot create '" + file.string() + "'"};
}
_close(descriptor);
return Status::Ok();
#else
int flags = O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK;
# if defined(O_NOFOLLOW)
flags |= O_NOFOLLOW;
# endif
const int descriptor = open(file.c_str(), flags, S_IRUSR | S_IWUSR);
if (descriptor < 0)
{
return Error{"cannot create '" + file.string() + "'"};
}
struct stat information = {};
if (fstat(descriptor, &information) != 0 ||
!S_ISREG(information.st_mode))
{
close(descriptor);
return Error{"'" + file.string() + "' is not a regular file"};
}
// A file that existed keeps its mode; make it private too.
fchmod(descriptor, S_IRUSR | S_IWUSR);
close(descriptor);
return Status::Ok();
#endif
}
std::string
UniqueName()
{
static std::atomic<unsigned> counter{0};
std::ostringstream text;
text << CurrentProcessId() << '-'
<< std::chrono::steady_clock::now().time_since_epoch().count()
<< '-' << std::this_thread::get_id() << '-' << ++counter;
return ToHex(Fnv1a64(text.str()));
}
} // namespace Progmasoft::Catch3::Runner
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