sbuild-lock.h

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00001 /* Copyright © 2005-2007  Roger Leigh <rleigh@debian.org>
00002  *
00003  * schroot is free software: you can redistribute it and/or modify it
00004  * under the terms of the GNU General Public License as published by
00005  * the Free Software Foundation, either version 3 of the License, or
00006  * (at your option) any later version.
00007  *
00008  * schroot is distributed in the hope that it will be useful, but
00009  * WITHOUT ANY WARRANTY; without even the implied warranty of
00010  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00011  * General Public License for more details.
00012  *
00013  * You should have received a copy of the GNU General Public License
00014  * along with this program.  If not, see
00015  * <http://www.gnu.org/licenses/>.
00016  *
00017  *********************************************************************/
00018 
00019 #ifndef SBUILD_LOCK_H
00020 #define SBUILD_LOCK_H
00021 
00022 #include <sbuild/sbuild-custom-error.h>
00023 
00024 #include <string>
00025 
00026 #include <sys/time.h>
00027 #include <fcntl.h>
00028 #include <signal.h>
00029 
00030 namespace sbuild
00031 {
00032 
00037   class lock
00038   {
00039   public:
00041     enum type
00042       {
00043         LOCK_SHARED    = F_RDLCK, 
00044         LOCK_EXCLUSIVE = F_WRLCK, 
00045         LOCK_NONE      = F_UNLCK  
00046       };
00047 
00049     enum error_code
00050       {
00051         TIMEOUT_HANDLER,      
00052         TIMEOUT_SET,          
00053         TIMEOUT_CANCEL,       
00054         LOCK,                 
00055         UNLOCK,               
00056         LOCK_TIMEOUT,         
00057         UNLOCK_TIMEOUT,       
00058         DEVICE_LOCK,          
00059         DEVICE_LOCK_TIMEOUT,  
00060         DEVICE_TEST,          
00061         DEVICE_UNLOCK,        
00062         DEVICE_UNLOCK_TIMEOUT 
00063       };
00064 
00066     typedef custom_error<error_code> error;
00067 
00074     virtual void
00075     set_lock (type         lock_type,
00076               unsigned int timeout) = 0;
00077 
00082     virtual void
00083     unset_lock () = 0;
00084 
00085   protected:
00087     lock ();
00089     virtual ~lock ();
00090 
00096     void
00097     set_alarm ();
00098 
00103     void
00104     clear_alarm ();
00105 
00115     void
00116     set_timer (struct itimerval const& timer);
00117 
00124     void
00125     unset_timer ();
00126 
00127   private:
00129     struct sigaction saved_signals;
00130   };
00131 
00136   class file_lock : public lock
00137   {
00138   public:
00144     file_lock (int fd);
00145 
00147     virtual ~file_lock ();
00148 
00149     virtual void
00150     set_lock (lock::type   lock_type,
00151               unsigned int timeout);
00152 
00153     virtual void
00154     unset_lock ();
00155 
00156   private:
00158     int fd;
00160     bool locked;
00161   };
00162 
00169   class device_lock : public lock
00170   {
00171   public:
00177     device_lock (std::string const& device);
00178 
00180     virtual ~device_lock ();
00181 
00182     virtual void
00183     set_lock (lock::type   lock_type,
00184               unsigned int timeout);
00185 
00186     virtual void
00187     unset_lock ();
00188 
00189   private:
00191     std::string device;
00193     bool locked;
00194   };
00195 
00196 }
00197 
00198 #endif /* SBUILD_LOCK_H */
00199 
00200 /*
00201  * Local Variables:
00202  * mode:C++
00203  * End:
00204  */

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