sbuild-lock.h

/* Copyright © 2005-2007  Roger Leigh <rleigh@debian.org>
 *
 * schroot 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 3 of the License, or
 * (at your option) any later version.
 *
 * schroot 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 *********************************************************************/

#ifndef SBUILD_LOCK_H
#define SBUILD_LOCK_H

#include <sbuild/sbuild-lock.h>
#include <sbuild/sbuild-custom-error.h>

#include <string>

#include <sys/time.h>
#include <fcntl.h>
#include <signal.h>

namespace sbuild
{

  class lock
  {
  public:
    enum type
      {
        LOCK_SHARED    = F_RDLCK, 
        LOCK_EXCLUSIVE = F_WRLCK, 
        LOCK_NONE      = F_UNLCK  
      };

    enum error_code
      {
        TIMEOUT_HANDLER,      
        TIMEOUT_SET,          
        TIMEOUT_CANCEL,       
        LOCK,                 
        UNLOCK,               
        LOCK_TIMEOUT,         
        UNLOCK_TIMEOUT,       
        DEVICE_LOCK,          
        DEVICE_LOCK_TIMEOUT,  
        DEVICE_TEST,          
        DEVICE_UNLOCK,        
        DEVICE_UNLOCK_TIMEOUT 
      };

    typedef custom_error<error_code> error;

    virtual void
    set_lock (type         lock_type,
              unsigned int timeout) = 0;

    virtual void
    unset_lock () = 0;

  protected:
    lock ();
    virtual ~lock ();

    void
    set_alarm ();

    void
    clear_alarm ();

    void
    set_timer (struct itimerval const& timer);

    void
    unset_timer ();

  private:
    struct sigaction saved_signals;
  };

  class file_lock : public lock
  {
  public:
    file_lock (int fd);

    virtual ~file_lock ();

    virtual void
    set_lock (lock::type   lock_type,
              unsigned int timeout);

    virtual void
    unset_lock ();

  private:
    int fd;
    bool locked;
  };

#ifdef SBUILD_FEATURE_DEVLOCK

  class device_lock : public lock
  {
  public:
    device_lock (std::string const& device);

    virtual ~device_lock ();

    virtual void
    set_lock (lock::type   lock_type,
              unsigned int timeout);

    virtual void
    unset_lock ();

  private:
    std::string device;
    bool locked;
  };
#endif // SBUILD_FEATURE_DEVLOCK

}

#endif /* SBUILD_LOCK_H */

/*
 * Local Variables:
 * mode:C++
 * End:
 */