pass lenght of datablobs into the directory compare function to avoid overreads

3 files changed, 17 insertions, 12 deletions

diff --git a/camlibs/canon/canon.c b/camlibs/canon/canon.c
index b8ca56393..9393f0b0e 100644
--- a/camlibs/canon/canon.c
+++ b/camlibs/canon/canon.c
@@ -1284,7 +1284,9 @@ canon_int_capture_preview (Camera *camera, unsigned char **data, unsigned int *l
  * canon_int_find_new_image:
  * @camera: Camera * to this camera
  * @initial_state: Camera directory dump before image capture
+ * @initial_state_len: Lengt of before dump 
  * @final_state: Directory dump after image capture
+ * @final_state_len: Length of after dump
  * @path: Will be filled in with the path and filename of the captured
  *        image, in canonical gphoto2 format.
  *
@@ -1293,8 +1295,11 @@ canon_int_capture_preview (Camera *camera, unsigned char **data, unsigned int *l
  * and its pathname is decoded into the given CameraFilePath.
  *
  */
-void canon_int_find_new_image ( Camera *camera, unsigned char *initial_state, unsigned char *final_state,
-                           CameraFilePath *path )
+void canon_int_find_new_image (
+		Camera *camera,
+		unsigned char *initial_state, unsigned int initial_state_length,
+		unsigned char *final_state, unsigned int final_state_length,
+		CameraFilePath *path )
 {
         char *old_entry = (char *)initial_state, *new_entry = (char *)final_state;
 
@@ -1633,12 +1638,13 @@ canon_int_capture_image (Camera *camera, CameraFilePath *path,
                 }
 
                 /* Find new file name in camera directory */
-                canon_int_find_new_image ( camera, initial_state, final_state, path );
+                canon_int_find_new_image ( camera, initial_state, initial_state_len, final_state, final_state_len, path );
 
 		/* Save this state to the camera directory state */
 		if (camera->pl->directory_state)
 			free (camera->pl->directory_state);
 		camera->pl->directory_state = final_state;
+		camera->pl->directory_state_length = final_state_len;
 
                 free ( initial_state );
                 break;
diff --git a/camlibs/canon/canon.h b/camlibs/canon/canon.h
index 34750ac2d..06cec2b3f 100644
--- a/camlibs/canon/canon.h
+++ b/camlibs/canon/canon.h
@@ -497,6 +497,7 @@ struct _CameraPrivateLibrary
 	int cached_ready;       /* whether the camera is ready to rock */
 
 	unsigned char *directory_state;	/* directory content state for wait_for_event */
+	unsigned int directory_state_length;	/* length of directory content state for wait_for_event */
 
 	long image_key, thumb_length, image_length; /* For immediate download of captured image */
 	long image_b_key, image_b_length; /* For immediate download of secondary captured image */
@@ -722,7 +723,7 @@ int canon_int_get_zoom(Camera *camera, unsigned char *zoom_level, unsigned char
  */
 int canon_int_get_release_params (Camera *camera, GPContext *context);
 
-void canon_int_find_new_image ( Camera *camera, unsigned char *initial_state, unsigned char *final_state, CameraFilePath *path );
+void canon_int_find_new_image ( Camera *camera, unsigned char *initial_state, unsigned int initial_state_length, unsigned char *final_state, unsigned int final_state_length, CameraFilePath *path );
 
 
 /* path conversion - needs drive letter, and therefore cannot be moved
diff --git a/camlibs/canon/usb.c b/camlibs/canon/usb.c
index d43d32bb6..c655b3c1d 100644
--- a/camlibs/canon/usb.c
+++ b/camlibs/canon/usb.c
@@ -940,11 +940,11 @@ canon_usb_wait_for_event (Camera *camera, int timeout,
 	unsigned char *final_state = NULL; /* For comparing
 					     * before/after
 					     * directories */
-	unsigned int directory_state_len, final_state_len;
+	unsigned int final_state_len;
         int status = GP_OK;
 
 	if (!camera->pl->directory_state)
-		status = canon_usb_list_all_dirs ( camera, &camera->pl->directory_state, &directory_state_len, context );
+		status = canon_usb_list_all_dirs ( camera, &camera->pl->directory_state, &camera->pl->directory_state_length, context );
 	if (status < GP_OK) {
 		GP_DEBUG ("canon_usb_wait_for_event: status %d", status);
 		return status;
@@ -967,7 +967,7 @@ canon_usb_wait_for_event (Camera *camera, int timeout,
 		if (status < GP_OK)
 			return status;
 		/* Find new file name in camera directory */
-		canon_int_find_new_image ( camera, camera->pl->directory_state, final_state, path );
+		canon_int_find_new_image ( camera, camera->pl->directory_state, camera->pl->directory_state_length, final_state, final_state_len, path );
 		if (path->folder[0] != '/') {
 			free (path);
 			*eventtype = GP_EVENT_UNKNOWN;
@@ -976,6 +976,7 @@ canon_usb_wait_for_event (Camera *camera, int timeout,
 		}
 		free ( camera->pl->directory_state );
 		camera->pl->directory_state = final_state;
+		camera->pl->directory_state_length = final_state_len;
 		return GP_OK;
 	}
 	default:
@@ -1022,11 +1023,8 @@ canon_usb_capture_dialogue (Camera *camera, unsigned int *return_length, int *ph
                 *return_length = 0;
 
 	/* for later wait_event */
-	if (!camera->pl->directory_state) {
-		unsigned int directory_state_len;
-
-		status = canon_usb_list_all_dirs ( camera, &camera->pl->directory_state, &directory_state_len, context );
-	}
+	if (!camera->pl->directory_state)
+		status = canon_usb_list_all_dirs ( camera, &camera->pl->directory_state, &camera->pl->directory_state_length, context );
 
         GP_DEBUG ("canon_usb_capture_dialogue()");