WatchedFileSensor.h

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// -*- mode: C++; indent-tabs-mode: nil; c-basic-offset: 4; tab-width: 4; -*-
// vim: set shiftwidth=4 softtabstop=4 expandtab:
/*
 ********************************************************************
 ** NIDAS: NCAR In-situ Data Acquistion Software
 **
 ** 2011, Copyright University Corporation for Atmospheric Research
 **
 ** This program is free software; you can redistribute it and/or modify
 ** it under the terms of the GNU General Public License as published by
 ** the Free Software Foundation; either version 2 of the License, or
 ** (at your option) any later version.
 **
 ** This program is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 ** GNU General Public License for more details.
 **
 ** The LICENSE.txt file accompanying this software contains
 ** a copy of the GNU General Public License. If it is not found,
 ** write to the Free Software Foundation, Inc.,
 ** 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 **
 ********************************************************************
*/
 
#include <nidas/Config.h> 
#ifdef HAVE_SYS_INOTIFY_H
 
/* From inotify man page:
 * Inotify  was  merged into the 2.6.13 Linux kernel.  The required library inter‐
 * faces were added to glibc in version 2.4.   (IN_DONT_FOLLOW,  IN_MASK_ADD,  and
 * IN_ONLYDIR were only added in version 2.5.)
 * As of Aug 2011, we're using glibc 2.3.3 on the Vipers and Vulcans
 *      cat /opt/arcom/arm-linux/lib/libc.so
 *      ls -l /opt/arcom/arm-linux/lib/libc.so.6 ->  libc-2.3.3.so
 * So, there is no inotify on the Vipers/Vulcans until they are upgraded.
 * HAVE_SYS_INOTIFY_H will be defined by Scons if sys/inotify.h is found.
 */
 
#ifndef NIDAS_DYNLD_WATCHEDFILESENSOR_H
#define NIDAS_DYNLD_WATCHEDFILESENSOR_H
 
#include <nidas/core/CharacterSensor.h>
#include <nidas/core/UnixIODevice.h>
 
namespace nidas { namespace dynld {
 
using namespace nidas::core;
 
class WatchedFileSensor : public CharacterSensor
{
 
public:
 
    WatchedFileSensor();
 
    ~WatchedFileSensor();
 
    int getReadFd() const
    {
        return _inotifyfd;
    }
 
    int getWriteFd() const
    {
        return -1;
    }
 
    void open(int flags);
 
    /*
     * Stop monitoring the file.
     */
    void close();
 
    bool readSamples();
 
private:
 
    void getFileStatus();
 
    void getPathStatus(dev_t& dev, ino_t& inode);
 
    bool differentInode();
 
    void reopen();
 
    int _inotifyfd;
 
    int _watchd;
 
    uint32_t _events;
 
    IODevice* _iodev;
 
    int _flags;
 
    dev_t _dev;
 
    ino_t _inode;
 
    bool _seekToEnd;
 
    off_t _size;
 
    off_t _curpos;
 
    WatchedFileSensor(const  WatchedFileSensor&);
 
    WatchedFileSensor& operator=(const  WatchedFileSensor&);
 
};
 
}}  // namespace nidas namespace dynld
 
#endif
#endif  // HAVE_SYS_INOTIFY_H