CFileSystemWatcher.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#pragma once
 
#include <mrpt/system/os.h>
#include <thread>
#include <mutex>
#include <queue>
 
namespace mrpt
{
namespace system
{
/** This class subscribes to notifications of file system changes, thus it can
 * be used to efficiently stay informed about changes in a directory tree.
  *  - Windows: Requires Windows 2000 or newer.
  *  - Linux: Requires kernel 2.6.13 or newer.
  *  Using this class in an old Linux or other unsoported system (Unix,etc...)
 * has no effect, i.e. no notification will be ever received.
  *  \sa CDirectoryExplorer
 * \ingroup mrpt_system_grp
  */
class CFileSystemWatcher
{
   public:
        /** Each of the changes detected by utils::CFileSystemWatcher
          */
        struct TFileSystemChange
        {
                TFileSystemChange() {}
                /** Complete path of the file/directory that has changed. */
                std::string path{};
                /** Whether the event happened to a file or a directory. */
                bool isDir{false};
                bool eventModified{false};
                bool eventCloseWrite{false};
                bool eventDeleted{false};
                bool eventMovedTo{false};
                bool eventMovedFrom{false};
                bool eventCreated{false};
                bool eventAccessed{false};
        };
 
        using TFileSystemChangeList = std::deque<TFileSystemChange>;
 
        /** Creates the subscription to a specified path.
          * \param path The file or directory to watch.
          */
        CFileSystemWatcher(const std::string& path);
 
        /** Destructor
          */
        virtual ~CFileSystemWatcher();
 
        /** Call this method sometimes to get the list of changes in the watched
         * directory.
          *  \sa processChange
          */
        void getChanges(TFileSystemChangeList& out_list);
 
   private:
        /** Ended in "/" */
        std::string m_watchedDirectory;
#ifdef _WIN32
        void* m_hNotif{nullptr};
        std::thread m_watchThread;
        /** Watch thread; only needed in win32 */
        void thread_win32_watch();
        std::queue<TFileSystemChange*> m_queue_events_win32_msgs;
        mutable std::mutex m_queue_events_win32_cs;
#endif
 
#if defined(MRPT_OS_LINUX) || defined(__APPLE__)
        /** The fd returned by inotify_init. */
        int m_fd;
        /** The fd of the watch. */
        int m_wd;
#endif
 
};  // End of class def.
 
}  // End of namespace
}  // End of namespace