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#pragma once
#include "i18n.h"
#include <string>
#include <fstream>
#include "os/fs.h"
#include "fmt/format.h"
namespace stream
{
// An output stream wrapper which opens a temporary file next to the actual target,
// moving the temporary file over the target file on demand.
// If something goes wrong, a std::runtime_error is thrown.
class TemporaryOutputStream
{
private:
fs::path _targetFile;
fs::path _temporaryPath;
std::ofstream _stream;
public:
TemporaryOutputStream(const fs::path& targetFile) :
_targetFile(targetFile),
_temporaryPath(getTemporaryPath(_targetFile)),
_stream(_temporaryPath)
{
if (!_stream.is_open())
{
throw std::runtime_error(fmt::format(_("Cannot open file for writing: {0}"), _temporaryPath.string()));
}
}
~TemporaryOutputStream()
{
// Remove the temporary file if it still existing at the End Of Life of this object
if (_stream.is_open())
{
_stream.close();
}
if (fs::exists(_temporaryPath))
{
rMessage() << "Cleaning up temporary file " << _temporaryPath << std::endl;
try
{
fs::remove(_temporaryPath);
}
catch (fs::filesystem_error& e)
{
rError() << "Could not remove the temporary file " << _temporaryPath << std::endl
<< e.what() << std::endl;
}
}
}
std::ostream& getStream()
{
return _stream;
}
void closeAndReplaceTargetFile()
{
_stream.close();
// Move the temporary stream over the actual file, removing the target first
if (fs::exists(_targetFile))
{
try
{
fs::remove(_targetFile);
}
catch (fs::filesystem_error& e)
{
rError() << "Could not remove the file " << _targetFile.string() << std::endl
<< e.what() << std::endl;
throw std::runtime_error(fmt::format(_("Could not remove the file {0}"), _targetFile.string()));
}
}
try
{
fs::rename(_temporaryPath, _targetFile);
}
catch (fs::filesystem_error& e)
{
rError() << "Could not rename the temporary file " << _temporaryPath.string() << std::endl
<< e.what() << std::endl;
throw std::runtime_error(
fmt::format(_("Could not rename the temporary file {0}"), _temporaryPath.string()));
}
}
private:
static fs::path getTemporaryPath(const fs::path& targetFile)
{
fs::path tempFile = targetFile;
tempFile.remove_filename();
tempFile /= "_" + targetFile.filename().string();
return tempFile;
}
};
}
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