make calibration cache expire after one hour

backend/genesys_gl847.c

@@ -3952,6 +3952,9 @@ gl847_is_compatible_calibration (Genesys_Device * dev,
 				 Genesys_Calibration_Cache * cache,
 				 int for_overwrite)
 {
+#ifdef HAVE_SYS_TIME_H
+  struct timeval time;
+#endif
   SANE_Status status;
 
   DBG (DBG_proc, "gl847_is_compatible_calibration\n");
@@ -3971,6 +3974,19 @@ gl847_is_compatible_calibration (Genesys_Device * dev,
   if (dev->current_setup.half_ccd != cache->used_setup.half_ccd)
     return SANE_STATUS_UNSUPPORTED;
 
+  /* a cache entry expires after 60 minutes for non sheetfed scanners */
+#ifdef HAVE_SYS_TIME_H
+  gettimeofday (&time, NULL);
+  if ((time.tv_sec - cache->last_calibration > 60 * 60)
+      && (dev->model->is_sheetfed == SANE_FALSE)
+      && (dev->settings.scan_method == SCAN_METHOD_FLATBED))
+    {
+      DBG (DBG_proc,
+	   "gl847_is_compatible_calibration: expired entry, non compatible cache\n");
+      return SANE_STATUS_UNSUPPORTED;
+    }
+#endif
+
   DBG (DBG_proc, "gl847_is_compatible_calibration: completed\n");
 
   return SANE_STATUS_GOOD;