fix calibration file name collision

- handle the case where there are several identical scanners plugged in,
  and avoid sharing the same calibration file

ChangeLog

@@ -1,3 +1,8 @@
+2014-02-24 Stéphane Voltz <stef.dev@free.fr>
+	* doc/sane-genesys.man backend/genesys.[ch]:
+	avoid calibration file name collision in case of several identical
+	scanners
+
 2014-02-10 Louis Lagendijk <louis.lagendijk at gmail.com>
 	* backend/pixma_bjnp.c backend/pixma_bjnp.h backend/pixma_bjnp_private.h:
 	- Added support for Canon laser multi-functionals using the MFNP protocol over port 8610

backend/genesys.c

@@ -58,7 +58,7 @@
  * SANE backend for Genesys Logic GL646/GL841/GL842/GL843/GL846/GL847/GL124 based scanners
  */
 
-#define BUILD 2502
+#define BUILD 2503
 #define BACKEND_NAME genesys
 
 #include "genesys.h"
@@ -2153,7 +2153,10 @@ genesys_white_shading_calibration (Genesys_Device * dev)
 /* This calibration uses a scan over the calibration target, comprising a
  * black and a white strip. (So the motor must be on.)
  */
-GENESYS_STATIC SANE_Status
+#ifndef UNIT_TESTING
+static
+#endif
+SANE_Status
 genesys_dark_white_shading_calibration (Genesys_Device * dev)
 {
   SANE_Status status;
@@ -5381,6 +5384,107 @@ SANE_Range *range=NULL;
   return range;
 }
 
+/** @brief generate calibration cache file nam
+ * Generates the calibration cache file name to use.
+ * Tries to store the chache in $HOME/.sane or
+ * then fallbacks to $TMPDIR or TMP. The filename
+ * uses the model name if only one scanner is plugged
+ * else is uses the device name when several identical
+ * scanners are in use.
+ * @param currdev current scanner device
+ * @return an allocated string containing a file name
+ */
+GENESYS_STATIC char *calibration_filename(Genesys_Device *currdev)
+{
+  char *tmpstr;
+  char *ptr;
+  char filename[80];
+  Genesys_Device *dev;
+  unsigned int count;
+  unsigned int i;
+
+  /* allocate space for result */
+  tmpstr=malloc(PATH_MAX);
+  if(tmpstr==NULL)
+    {
+      return NULL;
+    }
+
+  /* first compute the DIR where we can store cache:
+   * 1 - home dir
+   * 2 - $TMPDIR
+   * 3 - $TMP
+   * 4 - tmp dir
+   * 5 - temp dir
+   * 6 - then resort to current dir
+   */
+  ptr = getenv ("HOME");
+  if(ptr==NULL)
+    {
+      ptr = getenv ("USERPROFILE");
+    }
+  if(ptr==NULL)
+    {
+      ptr = getenv ("TMPDIR");
+    }
+  if(ptr==NULL)
+    {
+      ptr = getenv ("TMP");
+    }
+
+  /* now choose filename:
+   * 1 - if only one scanner, name of the model
+   * 2 - if several scanners of the same model, use device name,
+   *     replacing special chars
+   */
+  count=0;
+  /* count models of the same names if several scanners attached */
+  if(num_devices>1)
+    {
+      for (dev = first_dev; dev; dev = dev->next)
+        {
+          if(strcmp(dev->model->name,currdev->model->name)==0)
+            {
+              count++;
+            }
+        }
+    }
+  if(count>1)
+    {
+      snprintf(filename,sizeof(filename),"%s.cal",currdev->file_name);
+      for(i=0;i<strlen(filename);i++)
+        {
+          if(filename[i]==':'||filename[i]==PATH_SEP)
+            {
+              filename[i]='_';
+            }
+        }
+    }
+  else
+    {
+      snprintf(filename,sizeof(filename),"%s.cal",currdev->model->name);
+    }
+
+  /* build final final name : store dir + filename */
+  if (NULL == ptr)
+    {
+      snprintf (tmpstr, PATH_MAX, "%s", filename);
+    }
+  else
+    {
+#ifdef HAVE_MKDIR
+      /* make sure .sane directory exists in existing store dir */
+      snprintf (tmpstr, PATH_MAX, "%s%c.sane", ptr, PATH_SEP);
+      mkdir(tmpstr,0700);
+#endif
+      snprintf (tmpstr, PATH_MAX, "%s%c.sane%c%s", ptr, PATH_SEP, PATH_SEP, filename);
+    }
+
+  DBG (DBG_info, "%s: calibration filename >%s<\n", __FUNCTION__, tmpstr);
+
+  return tmpstr;
+}
+
 
 static SANE_Status
 init_options (Genesys_Scanner * s)
@@ -5994,6 +6098,17 @@ check_present (SANE_String_Const devname)
   return SANE_STATUS_GOOD;
 }
 
+/** @brief add a scanner device
+ * Insert the given device into the backend list of devices.
+ * @param dev device to add
+ */
+GENESYS_STATIC void add_device(Genesys_Device *dev)
+{
+  ++num_devices;
+  dev->next = first_dev;
+  first_dev = dev;
+}
+
 static SANE_Status
 attach (SANE_String_Const devname, Genesys_Device ** devp, SANE_Bool may_wait)
 {
@@ -6096,9 +6211,7 @@ attach (SANE_String_Const devname, Genesys_Device ** devp, SANE_Bool may_wait)
 
   DBG (DBG_info, "attach: found %s flatbed scanner %s at %s\n",
        dev->model->vendor, dev->model->model, dev->file_name);
-  ++num_devices;
+  add_device(dev);
-  dev->next = first_dev;
-  first_dev = dev;
 
   if (devp)
     *devp = dev;
@@ -6190,6 +6303,8 @@ probe_genesys_devices (void)
       free (new_dev);
     }
 
+  DBG(DBG_info, "%s: %d devices currently attached\n", __FUNCTION__, num_devices);
+
   DBGCOMPLETED;
 
   return status;
@@ -6687,8 +6802,7 @@ sane_open (SANE_String_Const devicename, SANE_Handle * handle)
   Genesys_Device *dev;
   SANE_Status status;
   Genesys_Scanner *s;
-  char tmp_str[PATH_MAX];
+  char *tmpstr;
-  char *ptr;
 
   DBG (DBG_proc, "sane_open: start (devicename = `%s')\n", devicename);
 
@@ -6795,36 +6909,12 @@ sane_open (SANE_String_Const devicename, SANE_Handle * handle)
   RIE (dev->model->cmd_set->init (dev));
 
   /* here is the place to fetch a stored calibration cache */
-
+  tmpstr=calibration_filename(s->dev);
-  /* create calibration-filename
+  s->val[OPT_CALIBRATION_FILE].s = strdup (tmpstr);
-     lifted from plustek-usb.c
+  s->dev->calib_file = strdup (tmpstr);
-   */
-  /* we should add a unique identifying feature to the file name
-     to support multiple scanners of the same model, but to my
-     knowledge, there is no such thing in these scanners.
-     (At least the usb serial is always "0".)
-     TODO add an storedir option to genesys.conf
-   */
-
-  ptr = getenv ("HOME");
-  if (NULL == ptr)
-    {
-      sprintf (tmp_str, "/tmp/%s.cal", s->dev->model->name);
-    }
-  else
-    {
-#ifdef HAVE_MKDIR
-      /* make sure .sane directory exists */
-      sprintf (tmp_str, "%s/.sane", ptr);
-      mkdir(tmp_str,0700);
-#endif
-      sprintf (tmp_str, "%s/.sane/%s.cal", ptr, s->dev->model->name);
-    }
-
-  s->val[OPT_CALIBRATION_FILE].s = strdup (tmp_str);
-  s->dev->calib_file = strdup (tmp_str);
   DBG (DBG_info, "Calibration filename set to:\n");
   DBG (DBG_info, ">%s<\n", s->dev->calib_file);
+  free(tmpstr);
 
   /* now open file, fetch calibration records */
 

backend/genesys.h

@@ -49,6 +49,16 @@
 
 #include "genesys_low.h"
 
+#ifndef PATH_MAX
+# define PATH_MAX	1024
+#endif
+
+#if defined(_WIN32) || defined(HAVE_OS2_H)
+# define PATH_SEP	'\\'
+#else
+# define PATH_SEP	'/'
+#endif
+
 
 #define ENABLE(OPTION)  s->opt[OPTION].cap &= ~SANE_CAP_INACTIVE
 #define DISABLE(OPTION) s->opt[OPTION].cap |=  SANE_CAP_INACTIVE
@@ -148,5 +158,7 @@ typedef struct Genesys_Scanner
 
 #ifdef UNIT_TESTING
 SANE_Status genesys_dark_white_shading_calibration (Genesys_Device * dev);
+char *calibration_filename(Genesys_Device *currdev);
+void add_device(Genesys_Device *dev);
 #endif
 #endif /* not GENESYS_H */

doc/sane-genesys.man

@@ -52,7 +52,13 @@ in the feeder then start calibration either by passing the --calibrate option to
 or by clicking on the available 'calibrate' button in the 'advanced options' in a graphical
 frontend. The result of the calibration is stored in a file in the home directory of the user doing it.
 If you plug the scanner in another machine or use it with another account, calibration
-will have to be redone.
+will have to be redone, unles you use the \-\-calibration\-file option.
+If no home directory is defined,
+USERAPPPROFILE will be used, then TMPDIR or TMP. If none of these directories exist, the backend will try
+to write in the current working directory. Flatbed scanners alos make use of the calibration file as a cache
+to avoid calibration before each scan. Calibration file name is the name of the scanner model if only
+one scanner is detected. In the case of several identical model, the file name will be the name
+of the logical USB device name.
 
 .SH EXTRAS SCAN OPTIONS
 
@@ -112,9 +118,9 @@ next scan will happen.
 .B \-\-calibration\-file
 .RS
         Specify the calibration file name to use. At least the directory containing the file
-must exist, since it won't be created. This allow to handle the case of several identical devices
+must exist, since it won't be created. This option is disabled if the backend is ran
-that would otherwise use the same calibration data. This option is disabled if the backend is ran
+as root. It maybe used in case of sheet-fed scanners to share a calibration file for several
-as root.
+users.
 .RE
 
 .PP