libcryfs/vendor/spdlog/details/file_helper.h
2016-02-10 00:58:03 +01:00

143 lines
2.7 KiB
C++

//
// Copyright(c) 2015 Gabi Melman.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
//
#pragma once
// Helper class for file sink
// When failing to open a file, retry several times(5) with small delay between the tries(10 ms)
// Can be set to auto flush on every line
// Throw spdlog_ex exception on errors
#include <string>
#include <thread>
#include <chrono>
#include "os.h"
#include "log_msg.h"
namespace spdlog
{
namespace details
{
class file_helper
{
public:
const int open_tries = 5;
const int open_interval = 10;
explicit file_helper(bool force_flush) :
_fd(nullptr),
_force_flush(force_flush)
{}
file_helper(const file_helper&) = delete;
file_helper& operator=(const file_helper&) = delete;
~file_helper()
{
close();
}
void open(const std::string& fname, bool truncate = false)
{
close();
const char* mode = truncate ? "wb" : "ab";
_filename = fname;
for (int tries = 0; tries < open_tries; ++tries)
{
if (!os::fopen_s(&_fd, fname, mode))
return;
std::this_thread::sleep_for(std::chrono::milliseconds(open_interval));
}
throw spdlog_ex("Failed opening file " + fname + " for writing");
}
void reopen(bool truncate)
{
if (_filename.empty())
throw spdlog_ex("Failed re opening file - was not opened before");
open(_filename, truncate);
}
void flush()
{
std::fflush(_fd);
}
void close()
{
if (_fd)
{
std::fclose(_fd);
_fd = nullptr;
}
}
void write(const log_msg& msg)
{
size_t msg_size = msg.formatted.size();
auto data = msg.formatted.data();
if (std::fwrite(data, 1, msg_size, _fd) != msg_size)
throw spdlog_ex("Failed writing to file " + _filename);
if (_force_flush)
std::fflush(_fd);
}
long size()
{
if (!_fd)
throw spdlog_ex("Cannot use size() on closed file " + _filename);
auto pos = ftell(_fd);
if (fseek(_fd, 0, SEEK_END) != 0)
throw spdlog_ex("fseek failed on file " + _filename);
auto file_size = ftell(_fd);
if(fseek(_fd, pos, SEEK_SET) !=0)
throw spdlog_ex("fseek failed on file " + _filename);
if (file_size == -1)
throw spdlog_ex("ftell failed on file " + _filename);
return file_size;
}
const std::string& filename() const
{
return _filename;
}
static bool file_exists(const std::string& name)
{
return os::file_exists(name);
}
private:
FILE* _fd;
std::string _filename;
bool _force_flush;
};
}
}