[elpa] externals/diff-hl 09ffe8d 21/25: Introduce diff-hl-update-once, to avoid diffing twice in normal-mode

[Dmitry Gutov]

branch: externals/diff-hl
commit 09ffe8dce1af5fe32ab6e12e3a424504db365700
Author: Dmitry Gutov <dgutov@yandex.ru>
Commit: Dmitry Gutov <dgutov@yandex.ru>

    Introduce diff-hl-update-once, to avoid diffing twice in normal-mode
    
    Fixes #152
---
 diff-hl.el | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/diff-hl.el b/diff-hl.el
index 0f59263..11d9850 100644
--- a/diff-hl.el
+++ b/diff-hl.el
@@ -358,6 +358,15 @@ performance when viewing such files in certain conditions."
                 (overlay-put h 'insert-in-front-hooks hook)
                 (overlay-put h 'insert-behind-hooks hook)))))))))
 
+(defvar-local diff-hl--modified-tick nil)
+
+(put 'diff-hl--modified-tick 'permanent-local t)
+
+(defun diff-hl-update-once ()
+  (unless (equal diff-hl--modified-tick (buffer-chars-modified-tick))
+    (diff-hl-update)
+    (setq diff-hl--modified-tick (buffer-chars-modified-tick))))
+
 (defun diff-hl-add-highlighting (type shape)
   (let ((o (make-overlay (point) (point))))
     (overlay-put o 'diff-hl t)
@@ -571,7 +580,7 @@ The value of this variable is a mode line template as in
                     ;; let's wait until the state information is
                     ;; saved, in order not to fetch it twice.
                     'find-file-hook)
-                  'diff-hl-update t t)
+                  'diff-hl-update-once t t)
         (add-hook 'vc-checkin-hook 'diff-hl-update nil t)
         ;; https://github.com/magit/magit/issues/603
         (add-hook 'magit-revert-buffer-hook 'diff-hl-update nil t)