DeviceFile.cc

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// SPDX-FileCopyrightText: Deutsches Elektronen-Synchrotron DESY, MSK, ChimeraTK Project <chimeratk-support@desy.de>
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "DeviceFile.h"
 
#include "Exception.h"
#include <sys/stat.h>
 
#include <cstring>
#include <fcntl.h>
#include <iostream>
#include <utility>
 
namespace ChimeraTK {
 
  DeviceFile::DeviceFile(const std::string& deviceFilePath, int flags)
  : _path{deviceFilePath}, _fd{::open(_path.c_str(), flags)} {
#ifdef _DEBUG
    std::cout << "XDMA: opening device file " << _path << std::endl;
#endif
    if(_fd < 0) {
      throw runtime_error(_strerror("Cannot open device: "));
    }
  }
 
  DeviceFile::DeviceFile(DeviceFile&& d) : _path(std::move(d._path)), _fd(std::exchange(d._fd, 0)) {}
 
  DeviceFile::~DeviceFile() {
    if(_fd > 0) {
#ifdef _DEBUG
      std::cout << "XDMA: closing device file " << _path << std::endl;
#endif
      ::close(_fd);
    }
  }
 
  std::string DeviceFile::_strerror(const std::string& msg) const {
    char tmp[255];
    return msg + _path + ": " + ::strerror_r(errno, tmp, sizeof(tmp));
  }
 
  DeviceFile::operator int() const {
    return _fd;
  }
 
  std::string DeviceFile::name() const {
    return _path;
  }
 
  bool DeviceFile::goodState() const {
    struct stat s {};
    if(fstat(_fd, &s) != 0) {
      return false;
    }
    // check whether device file was deleted since opened
    return s.st_nlink > 0;
  }
 
} // namespace ChimeraTK