Support for killing the X terminal

Check whether frames are alive upon teardown, as it might not be
the case when the terminal is killed as
`delete-terminal-functions' might be invoked after the terminal is
deleted.

* exwm-core.el (exwm--terminal): New variable holding the terminal
EXWM runs under.
(exwm-init, exwm-exit): Set and unset it.

* exwm.el (exwm--on-delete-terminal): New function for exiting
EXWM when the terminal is deleted.
(exwm-init): Use it.

* exwm.el (exwm--confirm-kill-terminal, exwm-init): Ask for
confirmation before deleting terminal.

* exwm-workspace.el (exwm-workspace--fullscreen-workspace): New
function.  Ensure the frame is alive.
(exwm-workspace--add-frame-as-workspace): Use it.
(exwm-workspace--exit-minibuffer-frame): Cancel
`exwm-workspace--display-echo-area-timer'.
(exwm-workspace--exit-minibuffer-frame): Ensure the minibuffer
frame is alive.
(exwm-workspace--exit): Ignore dead workspace frames.

1 files changed, 23 insertions, 1 deletions

diff --git a/exwm.el b/exwm.el
index 4c1689a55615..9e2df1ad6411 100644
--- a/exwm.el
+++ b/exwm.el
@@ -604,6 +604,13 @@
                (eq selection xcb:Atom:WM_S0))
       (exwm-exit))))
 
+(defun exwm--on-delete-terminal (terminal)
+  "Handle terminal being deleted without Emacs being killed.
+This may happen when invoking `save-buffers-kill-terminal' within an emacsclient
+session."
+  (when (eq terminal exwm--terminal)
+    (exwm-exit)))
+
 (defun exwm--init-icccm-ewmh ()
   "Initialize ICCCM/EWMH support."
   (exwm--log)
@@ -840,6 +847,7 @@ manager.  If t, replace it, if nil, abort and ask the user if `ask'."
   (condition-case err
       (progn
         (exwm-enable 'undo)               ;never initialize again
+        (setq exwm--terminal (frame-terminal frame))
         (setq exwm--connection (xcb:connect))
         (set-process-query-on-exit-flag (slot-value exwm--connection 'process)
                                         nil) ;prevent query message on exit
@@ -862,6 +870,10 @@ manager.  If t, replace it, if nil, abort and ask the user if `ask'."
         ;; Disable some features not working well with EXWM
         (setq use-dialog-box nil
               confirm-kill-emacs #'exwm--confirm-kill-emacs)
+        (advice-add 'save-buffers-kill-terminal
+                    :before-while #'exwm--confirm-kill-terminal)
+        ;; Clean up if the terminal is deleted.
+        (add-hook 'delete-terminal-functions 'exwm--on-delete-terminal)
         (exwm--lock)
         (exwm--init-icccm-ewmh)
         (exwm-layout--init)
@@ -898,7 +910,9 @@ manager.  If t, replace it, if nil, abort and ask the user if `ask'."
   (when exwm--connection
     (xcb:flush exwm--connection)
     (xcb:disconnect exwm--connection))
-  (setq exwm--connection nil))
+  (setq exwm--connection nil)
+  (setq exwm--terminal nil)
+  (exwm--log "Exited"))
 
 ;;;###autoload
 (defun exwm-enable (&optional undo)
@@ -977,6 +991,14 @@ manager.  If t, replace it, if nil, abort and ask the user if `ask'."
                ;; For other types, return the value as-is.
                (t result))))))
 
+(defun exwm--confirm-kill-terminal (&optional _)
+  "Confirm before killing terminal."
+  ;; This is invoked instead of `save-buffers-kill-emacs' (C-x C-c) on client
+  ;; frames.
+  (if (eq (frame-terminal) exwm--terminal)
+      (exwm--confirm-kill-emacs "[EXWM] Kill terminal?")
+    t))
+
 (defun exwm--confirm-kill-emacs (prompt &optional force)
   "Confirm before exiting Emacs."
   (exwm--log)