use expiration time option

- use expiration  time option value to managed cached entries
- changelog for genesys build #2506

ChangeLog

@@ -1,3 +1,8 @@
+2015-04-12 Stéphane Voltz <stef.dev@free.fr>
+	* doc/sane-genesys.man backend/genesys.[ch] backend/genesys_low.c:
+	fix calibration cleared when calibration file loaded,
+	add expiration time option for cache.
+
 2015-04-07 Rolf Bensch <rolf at bensch hyphen online dot de>
 	* backend/pixma_mp810.c: Canon Pixma MP990 TPU scan patch from Guillaume
 	  Courtois.

backend/genesys.c

@@ -5320,6 +5320,9 @@ calc_parameters (Genesys_Scanner * s)
       s->dev->settings.brightness=0;
     }
 
+  /* cache expiration time */
+   s->dev->settings.expiration_time=s->val[OPT_EXPIRATION_TIME].w;
+
   return status;
 }
 

backend/genesys_low.c

@@ -1766,7 +1766,8 @@ int sanei_genesys_get_lowest_dpi(Genesys_Device *dev)
  * A calibration cache is compatible if color mode and x dpi match the user
  * requested scan. In the case of CIS scanners, dpi isn't a criteria.
  * flatbed cache entries are considred too old and then expires if they
- * are older dans 1h, forcing calcibration at least once an hour. */
+ * are older than the expiration time option, forcing calibration at least once
+ * then given time. */
 SANE_Status
 sanei_genesys_is_compatible_calibration (Genesys_Device * dev,
 				 Genesys_Calibration_Cache * cache,
@@ -1832,13 +1833,13 @@ sanei_genesys_is_compatible_calibration (Genesys_Device * dev,
       return SANE_STATUS_UNSUPPORTED;
     }
 
-  /* a cache entry expires after 60 minutes for non sheetfed scanners */
+  /* a cache entry expires after afetr expiration time for non sheetfed scanners */
   /* this is not taken into account when overwriting cache entries    */
 #ifdef HAVE_SYS_TIME_H
-  if(for_overwrite == SANE_FALSE)
+  if(for_overwrite == SANE_FALSE && dev->settings.expiration_time >=0)
     {
       gettimeofday (&time, NULL);
-      if ((time.tv_sec - cache->last_calibration > 60 * 60)
+      if ((time.tv_sec - cache->last_calibration > dev->settings.expiration_time*60)
           && (dev->model->is_sheetfed == SANE_FALSE)
           && (dev->settings.scan_method == SCAN_METHOD_FLATBED))
         {

backend/genesys_low.h

@@ -707,6 +707,9 @@ typedef struct
 
   /**< value for brightness enhancement in the [-100..100] range */
   int brightness;
+  
+  /**< cahe entries expiration time */
+  int expiration_time;
 } Genesys_Settings;
 
 typedef struct Genesys_Current_Setup