text: // Copyright (c) 2014-2019, AEON, The Monero Project
  // 
  // All rights reserved.
  // 
  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  // 
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  // 
  // 2. Redistributions in binary form must reproduce the above copyright notice, this list
  //    of conditions and the following disclaimer in the documentation and/or other
  //    materials provided with the distribution.
  // 
  // 3. Neither the name of the copyright holder nor the names of its contributors may be
  //    used to endorse or promote products derived from this software without specific
  //    prior written permission.
  // 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
  // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
  // THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  // 
  // Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
  
  #pragma once 
  
  #include <boost/thread/locks.hpp>
  #include <boost/thread/mutex.hpp>
  #include <boost/optional.hpp>
  #include <system_error>
  #include <csignal>
  #include <cstdio>
  #include <functional>
  #include <memory>
  #include <string>
  
  #ifdef _WIN32
  #include "windows.h"
  #include "misc_log_ex.h"
  #endif
  
  #include "crypto/hash.h"
  
  /*! \brief Various Tools
   *
   *  
   * 
   */
  namespace tools
  {
    //! Functional class for closing C file handles.
    struct close_file
    {
      void operator()(std::FILE* handle) const noexcept
      {
        if (handle)
        {
          std::fclose(handle);
        }
      }
    };
  
    //! A file restricted to process owner AND process. Deletes file on destruction.
    class private_file {
      std::unique_ptr<std::FILE, close_file> m_handle;
      std::string m_filename;
  
      private_file(std::FILE* handle, std::string&& filename) noexcept;
    public:
  
      //! `handle() == nullptr && filename.empty()`.
      private_file() noexcept;
  
      /*! \return File only readable by owner and only used by this process
        OR `private_file{}` on error. */
      static private_file create(std::string filename);
  
      private_file(private_file&&) = default;
      private_file& operator=(private_file&&) = default;
  
      //! Deletes `filename()` and closes `handle()`.
      ~private_file() noexcept;
  
      std::FILE* handle() const noexcept { return m_handle.get(); }
      const std::string& filename() const noexcept { return m_filename; }
    };
  
    class file_locker
    {
    public:
      file_locker(const std::string &filename);
      ~file_locker();
      bool locked() const;
    private:
  #ifdef WIN32
      HANDLE m_fd;
  #else
      int m_fd;
  #endif
    };
  
    /*! \brief Returns the default data directory.
     *
     * \details Windows < Vista: C:\\Documents and Settings\\Username\\Application Data\\CRYPTONOTE_NAME
     *
     * Windows >= Vista: C:\\Users\\Username\\AppData\\Roaming\\CRYPTONOTE_NAME
     *
     * Mac: ~/Library/Application Support/CRYPTONOTE_NAME
     *
     * Unix: ~/.CRYPTONOTE_NAME
     */
    std::string get_default_data_dir();
  
  #ifdef WIN32
    /**
     * @brief 
     *
     * @param nfolder
     * @param iscreate
     *
     * @return 
     */
    std::string get_special_folder_path(int nfolder, bool iscreate);
  #endif
  
    /*! \brief Returns the OS version string
     *
     * \details This is a wrapper around the primitives
     * get_windows_version_display_string() and
     * get_nix_version_display_string()
     */
    std::string get_os_version_string();
  
    /*! \brief creates directories for a path
     *
     *  wrapper around boost::filesyste::create_directories.  
     *  (ensure-directory-exists): greenspun's tenth rule in action!
     */
    bool create_directories_if_necessary(const std::string& path);
    /*! \brief std::rename wrapper for nix and something strange for windows.
     */
    std::error_code replace_file(const std::string& replacement_name, const std::string& replaced_name);
  
    bool sanitize_locale();
  
    bool disable_core_dumps();
  
    bool on_startup();
  
    /*! \brief Defines a signal handler for win32 and *nix
     */
    class signal_handler
    {
    public:
      /*! \brief installs a signal handler  */
      template<typename T>
      static bool install(T t)
      {
  #if defined(WIN32)
        bool r = TRUE == ::SetConsoleCtrlHandler(&win_handler, TRUE);
        if (r)
        {
          m_handler = t;
        }
        return r;
  #else
        static struct sigaction sa;
        memset(&sa, 0, sizeof(struct sigaction));
        sa.sa_handler = posix_handler;
        sa.sa_flags = 0;
        /* Only blocks SIGINT, SIGTERM and SIGPIPE */
        sigaction(SIGINT, &sa, NULL);
        signal(SIGTERM, posix_handler);
        signal(SIGPIPE, SIG_IGN);
        m_handler = t;
        return true;
  #endif
      }
  
    private:
  #if defined(WIN32)
      /*! \brief Handler for win */
      static BOOL WINAPI win_handler(DWORD type)
      {
        if (CTRL_C_EVENT == type || CTRL_BREAK_EVENT == type)
        {
          handle_signal(type);
        }
        else
        {
          MGINFO_RED("Got control signal " << type << ". Exiting without saving...");
          return FALSE;
        }
        return TRUE;
      }
  #else
      /*! \brief handler for NIX */
      static void posix_handler(int type)
      {
        handle_signal(type);
      }
  #endif
  
      /*! \brief calles m_handler */
      static void handle_signal(int type)
      {
        static boost::mutex m_mutex;
        boost::unique_lock<boost::mutex> lock(m_mutex);
        m_handler(type);
      }
  
      /*! \brief where the installed handler is stored */
      static std::function<void(int)> m_handler;
    };
  
    void set_strict_default_file_permissions(bool strict);
  
    void set_max_concurrency(unsigned n);
    unsigned get_max_concurrency();
  
    bool is_local_address(const std::string &address);
    int vercmp(const char *v0, const char *v1); // returns < 0, 0, > 0, similar to strcmp, but more human friendly than lexical - does not attempt to validate
  
    bool sha256sum(const uint8_t *data, size_t len, crypto::hash &hash);
    bool sha256sum(const std::string &filename, crypto::hash &hash);
  
    boost::optional<bool> is_hdd(const char *path);
  
    boost::optional<std::pair<uint32_t, uint32_t>> parse_subaddress_lookahead(const std::string& str);
  
    std::string glob_to_regex(const std::string &val);
  #ifdef _WIN32
    std::string input_line_win();
  #endif
  }
  