[PATCH v4 4/6] emacs: notmuch-show: refresh all windows displaying buffer

[Ioan-Adrian Ratiu <adi@adirat.com>]

This updates all windows displaying a notmuch-show buffer when the
buffer refresh function is called.

Each window displaying a notmuch-show buffer has its own currently
displayed message based on the (point) location. We store the state
of all displayed windows when refreshing a notmuch-show buffer and
re-apply the current shown message (point) for all windows.

Implementation note: Each window has it's own (point) value, besides
the buffer's (point) value. Sometimes these values are identical like
in the case where a single window displays a buffer. When multiple
windows display a buffer, (point) returns each window's specific value.
What we are storing in this changeset is the window values not the
buffer point values. The buffer's point is returned only if no window
is displaying the buffer, a case we do not care about here.

Signed-off-by: Ioan-Adrian Ratiu <adi@adirat.com>
---
 emacs/notmuch-show.el | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 1772d10..bd69751 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -1317,8 +1317,13 @@ If no messages match the query return NIL."
 
 This includes:
  - the list of open messages,
- - the current message."
-  (list (notmuch-show-get-message-id) (notmuch-show-get-message-ids-for-open-messages)))
+ - the combination of current message id with/for each visible window."
+  (let* ((win-list (get-buffer-window-list (current-buffer) nil t))
+	 (win-id-combo (mapcar (lambda (win)
+				 (with-selected-window win
+				   (list win (notmuch-show-get-message-id))))
+			       win-list)))
+    (list win-id-combo (notmuch-show-get-message-ids-for-open-messages))))
 
 (defun notmuch-show-get-query ()
   "Return the current query in this show buffer"
@@ -1345,8 +1350,8 @@ This includes:
 This includes:
  - opening the messages previously opened,
  - closing all other messages,
- - moving to the correct current message."
-  (let ((current (car state))
+ - moving to the correct current message in every displayed window."
+  (let ((win-msg-alist (car state))
 	(open (cadr state)))
 
     ;; Open those that were open.
@@ -1355,8 +1360,10 @@ This includes:
 					   (member (notmuch-show-get-message-id) open))
 	  until (not (notmuch-show-goto-message-next)))
 
-    ;; Go to the previously open message.
-    (notmuch-show-goto-message current)))
+    (dolist (win-msg-pair win-msg-alist)
+      (with-selected-window (car win-msg-pair)
+	;; Go to the previously open message in this window
+	(notmuch-show-goto-message (cadr win-msg-pair))))))
 
 (defun notmuch-show-refresh-view (&optional reset-state ignore)
   "Refresh the current view.
-- 
2.10.0