CFileSystemWatcher.h

Go to the documentation of this file.

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, 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 |
   +------------------------------------------------------------------------+ */
#ifndef CFileSystemWatcher_H
#define CFileSystemWatcher_H

#include <mrpt/utils/utils_defs.h>
#include <mrpt/system/os.h>
#include <mrpt/utils/CThreadSafeQueue.h>
#include <thread>

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_base_grp
  */
class CFileSystemWatcher
{
   public:
        /** Each of the changes detected by utils::CFileSystemWatcher
          */
        struct TFileSystemChange
        {
                TFileSystemChange()
                        : path(),
                          isDir(false),
                          eventModified(false),
                          eventCloseWrite(false),
                          eventDeleted(false),
                          eventMovedTo(false),
                          eventMovedFrom(false),
                          eventCreated(false),
                          eventAccessed(false)
                {
                }

                /** Complete path of the file/directory that has changed. */
                std::string path;
                /** Whether the event happened to a file or a directory. */
                bool isDir;
                bool eventModified;
                bool eventCloseWrite;
                bool eventDeleted;
                bool eventMovedTo;
                bool eventMovedFrom;
                bool eventCreated;
                bool eventAccessed;
        };

        typedef std::deque<TFileSystemChange> TFileSystemChangeList;

        /** 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 MRPT_OS_WINDOWS
        void* m_hNotif;
        std::thread m_watchThread;
        /** Watch thread; only needed in win32 */
        void thread_win32_watch();
        mrpt::utils::CThreadSafeQueue<TFileSystemChange> m_queue_events_win32;

#endif

#if defined(MRPT_OS_LINUX) || defined(MRPT_OS_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

#endif