[elpa] externals-release/ement 588113092f 4/6: Fix: (ement-room-list) Another attempt

[ELPA Syncer]

branch: externals-release/ement
commit 588113092f759fbf262847b258037ca2fd9e457f
Author: Adam Porter <adam@alphapapa.net>
Commit: Adam Porter <adam@alphapapa.net>

    Fix: (ement-room-list) Another attempt
    
    This seems to work most of the time, but not all of the time.  See
    comment at bottom of function.  This will have to be good enough for
    now.
---
 README.org         |   3 +-
 ement-room-list.el | 160 +++++++++++++++++++++++++++++------------------------
 2 files changed, 90 insertions(+), 73 deletions(-)

diff --git a/README.org b/README.org
index fe5b3e20e5..a6882d9db8 100644
--- a/README.org
+++ b/README.org
@@ -298,7 +298,8 @@ Note that, while ~matrix-client~ remains usable, and 
probably will for some time
 
 ** 0.9.3-pre
 
-Nothing new yet.
+*Fixes*
++ Another attempt at restoring position in room list when refreshing.
 
 ** 0.9.2
 
diff --git a/ement-room-list.el b/ement-room-list.el
index 516ac80b05..076314e13e 100644
--- a/ement-room-list.el
+++ b/ement-room-list.el
@@ -547,7 +547,8 @@ After showing it, its window is selected.  The buffer is 
named
 BUFFER-NAME and is shown with DISPLAY-BUFFER-ACTION; or if
 DISPLAY-BUFFER-ACTION is nil, the buffer is not displayed."
   (interactive)
-  (let (format-table column-sizes window-start)
+  (let ((window-start 0) (window-point 0)
+        format-table column-sizes)
     (cl-labels (;; (heading-face
                 ;;  (depth) (list :inherit (list 'bufler-group 
(bufler-level-face depth))))
                 (format-item (item) (gethash item format-table))
@@ -615,77 +616,92 @@ DISPLAY-BUFFER-ACTION is nil, the buffer is not 
displayed."
       ;;   (kill-buffer buffer-name))
       (unless ement-sessions
         (error "Ement: Not connected.  Use `ement-connect' to connect"))
-      (with-current-buffer (get-buffer-create buffer-name)
-        (ement-room-list-mode)
-        (let* ((room-session-vectors
-                (cl-loop for (_id . session) in ement-sessions
-                         append (cl-loop for room in (ement-session-rooms 
session)
-                                         collect (vector room session))))
-               (taxy (cl-macrolet ((first-item
-                                    (pred) `(lambda (taxy)
-                                              (when (taxy-items taxy)
-                                                (,pred (car (taxy-items 
taxy))))))
-                                   (name= (name) `(lambda (taxy)
-                                                    (equal ,name (taxy-name 
taxy)))))
-                       (thread-last
-                         (make-fn
-                          :name "Ement Rooms"
-                          :take (taxy-make-take-function keys 
ement-room-list-keys))
-                         (taxy-fill room-session-vectors)
-                         (taxy-sort #'> #'item-latest-ts)
-                         (taxy-sort #'t<nil #'item-invited-p)
-                         (taxy-sort #'t<nil #'item-favourite-p)
-                         (taxy-sort #'t>nil #'item-low-priority-p)
-                         (taxy-sort #'t<nil #'item-unread-p)
-                         (taxy-sort #'t<nil #'item-space-p)
-                         ;; Within each taxy, left rooms should be sorted last 
so that one
-                         ;; can never be the first room in the taxy (unless 
it's the taxy
-                         ;; of left rooms), which would cause the taxy to be 
incorrectly
-                         ;; sorted last.
-                         (taxy-sort #'t>nil #'item-left-p)
-                         (taxy-sort* #'string< #'taxy-name)
-                         (taxy-sort* #'> #'taxy-latest-ts)
-                         (taxy-sort* #'t<nil (name= "Buffers"))
-                         (taxy-sort* #'t<nil (first-item item-unread-p))
-                         (taxy-sort* #'t<nil (first-item item-favourite-p))
-                         (taxy-sort* #'t<nil (first-item item-invited-p))
-                         (taxy-sort* #'t>nil (first-item item-space-p))
-                         (taxy-sort* #'t>nil (name= "Low-priority"))
-                         (taxy-sort* #'t>nil (first-item item-left-p)))))
-               (taxy-magit-section-insert-indent-items nil)
-               (inhibit-read-only t)
-               (format-cons (taxy-magit-section-format-items
-                             ement-room-list-columns 
ement-room-list-column-formatters taxy))
-               (pos (point))
-               (section-ident (when (magit-current-section)
-                                (magit-section-ident 
(magit-current-section)))))
-          (setf format-table (car format-cons)
-                column-sizes (cdr format-cons)
-                header-line-format (taxy-magit-section-format-header
-                                    column-sizes 
ement-room-list-column-formatters)
-                window-start (if (get-buffer-window buffer-name)
-                                 (window-start (get-buffer-window buffer-name))
-                               0))
-          (when ement-room-list-visibility-cache
-            (setf magit-section-visibility-cache 
ement-room-list-visibility-cache))
-          (add-hook 'kill-buffer-hook #'ement-room-list--cache-visibility nil 
'local)
-          (delete-all-overlays)
-          (erase-buffer)
-          (save-excursion
-            (taxy-magit-section-insert taxy :items 'first
-              ;; :blank-between-depth bufler-taxy-blank-between-depth
-              :initial-depth 0))
-          (goto-char pos)
-          (when (and section-ident (magit-get-section section-ident))
-            (goto-char (oref (magit-get-section section-ident) start)))))
-      (when display-buffer-action
-        (when-let ((window (display-buffer buffer-name display-buffer-action)))
-          (select-window window)))
-      (when (get-buffer-window buffer-name)
-        (set-window-start (get-buffer-window buffer-name) window-start))
-      ;; NOTE: In order for `bookmark--jump-via' to work properly, the 
restored buffer
-      ;; must be set as the current buffer, so we have to do this explicitly 
here.
-      (set-buffer buffer-name))))
+      (if (not (cl-loop for (_id . session) in ement-sessions
+                        thereis (ement-session-rooms session)))
+          (ement-message "No rooms have been joined")
+        (with-current-buffer (get-buffer-create buffer-name)
+          (ement-room-list-mode)
+          (let* ((room-session-vectors
+                  (cl-loop for (_id . session) in ement-sessions
+                           append (cl-loop for room in (ement-session-rooms 
session)
+                                           collect (vector room session))))
+                 (taxy (cl-macrolet ((first-item
+                                      (pred) `(lambda (taxy)
+                                                (when (taxy-items taxy)
+                                                  (,pred (car (taxy-items 
taxy))))))
+                                     (name= (name) `(lambda (taxy)
+                                                      (equal ,name (taxy-name 
taxy)))))
+                         (thread-last
+                           (make-fn
+                            :name "Ement Rooms"
+                            :take (taxy-make-take-function keys 
ement-room-list-keys))
+                           (taxy-fill room-session-vectors)
+                           (taxy-sort #'> #'item-latest-ts)
+                           (taxy-sort #'t<nil #'item-invited-p)
+                           (taxy-sort #'t<nil #'item-favourite-p)
+                           (taxy-sort #'t>nil #'item-low-priority-p)
+                           (taxy-sort #'t<nil #'item-unread-p)
+                           (taxy-sort #'t<nil #'item-space-p)
+                           ;; Within each taxy, left rooms should be sorted 
last so that one
+                           ;; can never be the first room in the taxy (unless 
it's the taxy
+                           ;; of left rooms), which would cause the taxy to be 
incorrectly
+                           ;; sorted last.
+                           (taxy-sort #'t>nil #'item-left-p)
+                           (taxy-sort* #'string< #'taxy-name)
+                           (taxy-sort* #'> #'taxy-latest-ts)
+                           (taxy-sort* #'t<nil (name= "Buffers"))
+                           (taxy-sort* #'t<nil (first-item item-unread-p))
+                           (taxy-sort* #'t<nil (first-item item-favourite-p))
+                           (taxy-sort* #'t<nil (first-item item-invited-p))
+                           (taxy-sort* #'t>nil (first-item item-space-p))
+                           (taxy-sort* #'t>nil (name= "Low-priority"))
+                           (taxy-sort* #'t>nil (first-item item-left-p)))))
+                 (taxy-magit-section-insert-indent-items nil)
+                 (inhibit-read-only t)
+                 (format-cons (taxy-magit-section-format-items
+                               ement-room-list-columns 
ement-room-list-column-formatters taxy))
+                 (pos (point))
+                 (section-ident (when (magit-current-section)
+                                  (magit-section-ident 
(magit-current-section)))))
+            (setf format-table (car format-cons)
+                  column-sizes (cdr format-cons)
+                  header-line-format (taxy-magit-section-format-header
+                                      column-sizes 
ement-room-list-column-formatters))
+            (when-let ((window (get-buffer-window (current-buffer))))
+              (setf window-point (window-point window)
+                    window-start (window-start window)))
+            (when ement-room-list-visibility-cache
+              (setf magit-section-visibility-cache 
ement-room-list-visibility-cache))
+            (add-hook 'kill-buffer-hook #'ement-room-list--cache-visibility 
nil 'local)
+            ;; Before this point, no changes have been made to the buffer's 
contents.
+            (delete-all-overlays)
+            (erase-buffer)
+            (save-excursion
+              (taxy-magit-section-insert taxy :items 'first
+                ;; :blank-between-depth bufler-taxy-blank-between-depth
+                :initial-depth 0))
+            (if-let* ((section-ident)
+                      (section (magit-get-section section-ident)))
+                (goto-char (oref section start))
+              (goto-char pos))))
+        (when display-buffer-action
+          (when-let ((window (display-buffer buffer-name 
display-buffer-action)))
+            (select-window window)))
+        (when-let ((window (get-buffer-window buffer-name)))
+          (set-window-start window window-start)
+          (set-window-point window window-point))
+        ;; FIXME: Despite all this code to save and restore point and window 
point and
+        ;; window start, when I send a message from the minibuffer, or when I 
abort
+        ;; sending a message from the minibuffer, point is moved to the 
beginning of the
+        ;; buffer.  While the minibuffer is open (and the typing messages are 
being sent
+        ;; to the server, causing it to repeatedly sync), the point stays in 
the correct
+        ;; place.  I can't find any reason why this happens.  It makes no 
sense.  And
+        ;; while trying to debug the problem, somehow Emacs got put into an 
unbreakable,
+        ;; infinite loop twice; even C-g and SIGUSR2 didn't stop it.
+
+        ;; NOTE: In order for `bookmark--jump-via' to work properly, the 
restored buffer
+        ;; must be set as the current buffer, so we have to do this explicitly 
here.
+        (set-buffer buffer-name)))))
 
 (cl-defun ement-room-list-side-window (&key (side 'left))
   "Show room list in side window on SIDE.