Check whether place can be restored successfully

Closes #29

1 files changed, 12 insertions, 3 deletions

diff --git a/nov.el b/nov.el
index a9c57cd..f3e0a25 100644
--- a/nov.el
+++ b/nov.el
@@ -650,6 +650,11 @@ Saving is only done if `nov-save-place-file' is set."
       (with-temp-file nov-save-place-file
         (insert (prin1-to-string places))))))
 
+(defun nov--index-valid-p (documents index)
+  (and (integerp index)
+       (>= index 0)
+       (< index (length documents))))
+
 ;;;###autoload
 (define-derived-mode nov-mode special-mode "EPUB"
   "Major mode for reading EPUB documents"
@@ -686,9 +691,13 @@ Saving is only done if `nov-save-place-file' is set."
     (if place
         (let ((index (cdr (assq 'index place)))
               (point (cdr (assq 'point place))))
-          (setq nov-documents-index index)
-          (nov-render-document)
-          (goto-char point))
+          (if (nov--index-valid-p nov-documents index)
+              (progn
+                (setq nov-documents-index index)
+                (nov-render-document)
+                (goto-char point))
+            (warn "Couldn't restore last position")
+            (nov-render-document)))
       (nov-render-document))))
 
 (provide 'nov)