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) throw(nidas::util::IOException,
        nidas::util::InvalidParameterException);

    /*
     * Stop monitoring the file.
     */
    void close() throw(nidas::util::IOException);

    bool readSamples() throw(nidas::util::IOException);

private:

    void getFileStatus() throw(nidas::util::IOException);

    void getPathStatus(dev_t& dev, ino_t& inode) throw(nidas::util::IOException);

    bool differentInode() throw(nidas::util::IOException);

    void reopen() throw(nidas::util::IOException);

    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