bongo: Add cache

* common.el (durand-take): Declare as pure and side-effect free.

* durand-bongo.el (bongo-sub-redisplay): Do nothing when not playing,
  to avoid clearing the subtitles buffer when stopped.

(durand-bongo-time-process): A helper to replace nil values by 0 in
the return value of `parse-time-string'.

(bongo-sub-status-string): Use a cache to avoid searching for the
subtitle every second.

1 files changed, 1 insertions, 0 deletions

diff --git a/common.el b/common.el
index 871f069..94cbe3c 100644
--- a/common.el
+++ b/common.el
@@ -461,6 +461,7 @@ current line; negative ARG means to put the line upwards."
 (defun durand-take (n ls)
   "Return the first N items of LS.
 If the length of LS is less than N, then return the whole LS."
+  (declare (pure t) (side-effect-free t))
   (cond
    ((< (length ls) n) ls)
    ((let ((i 0) result)