Observe connection status on deinitialization

* exwm-workspace.el (exwm-workspace--remove-frame-as-workspace):
Add optional argument quit.

* exwm-background.el (exwm-background--exit):
* exwm-input.el (exwm-input--exit):
* exwm-manage.el (exwm-manage--unmanage-window):
* exwm-systemtray.el (exwm-systemtray--exit):
* exwm-workspace.el (exwm-workspace--exit-minibuffer-frame)
(exwm-workspace--exit):
* exwm-xim.el (exwm-xim--exit): Observe connection status when
deinitializing in order to support deinitializing when the
connection breaks.

exwm-background.el

@@ -172,19 +172,17 @@ replace it.")
 (defun exwm-background--init ()
   "Initialize background module."
   (exwm--log)
-
   (add-hook 'enable-theme-functions 'exwm-background--update)
   (add-hook 'disable-theme-functions 'exwm-background--update)
-
   (exwm-background--update))
 
 (defun exwm-background--exit ()
   "Uninitialize the background module."
   (exwm--log)
-
   (remove-hook 'enable-theme-functions 'exwm-background--update)
   (remove-hook 'disable-theme-functions 'exwm-background--update)
-  (when exwm-background--connection
+  (when (and exwm-background--connection
+             (slot-value exwm-background--connection 'connected))
     (xcb:disconnect exwm-background--connection))
   (setq exwm-background--pixmap nil
         exwm-background--connection nil

exwm-input.el

@@ -1215,7 +1215,7 @@ One use is to access the keymap bound to KEYS (as prefix keys) in char-mode."
   (when exwm-input--update-focus-timer
     (cancel-timer exwm-input--update-focus-timer))
   ;; Make input focus working even without a WM.
-  (when exwm--connection
+  (when (slot-value exwm--connection 'connected)
     (xcb:+request exwm--connection
         (make-instance 'xcb:SetInputFocus
                        :revert-to xcb:InputFocus:PointerRoot

exwm-manage.el

@@ -430,7 +430,9 @@ manager is shutting down."
       (exwm-workspace--update-workareas)
       (dolist (f exwm-workspace--list)
         (exwm-workspace--set-fullscreen f)))
-    (when (buffer-live-p buffer)
+    (when (and (buffer-live-p buffer)
+               ;; Invoked from `exwm-manage--exit' upon disconnection.
+               (slot-value exwm--connection 'connected))
       (with-current-buffer buffer
         ;; Unmap the X window.
         (xcb:+request exwm--connection
@@ -512,8 +514,11 @@ manager is shutting down."
 
 (defun exwm-manage--kill-buffer-query-function ()
   "Run in `kill-buffer-query-functions'."
-  (exwm--log "id=#x%x; buffer=%s" exwm--id (current-buffer))
+  (exwm--log "id=#x%x; buffer=%s" (or exwm--id 0) (current-buffer))
   (catch 'return
+    (when (or (not exwm--connection)
+              (not (slot-value exwm--connection 'connected)))
+      (throw 'return t))
     (when (or (not exwm--id)
               (xcb:+request-checked+request-check exwm--connection
                   (make-instance 'xcb:ChangeWindowAttributes

exwm-systemtray.el

@@ -652,6 +652,7 @@ indicate how to support actual transparency."
   "Exit the systemtray module."
   (exwm--log)
   (when exwm-systemtray--connection
+    (when (slot-value exwm-systemtray--connection 'connected)
       ;; Hide & reparent out the embedder before disconnection to prevent
       ;; embedded icons from being reparented to an Emacs frame (which is the
       ;; parent of the embedder).
@@ -664,7 +665,7 @@ indicate how to support actual transparency."
                          :parent exwm--root
                          :x 0
                          :y 0))
-    (xcb:disconnect exwm-systemtray--connection)
+      (xcb:disconnect exwm-systemtray--connection))
     (setq exwm-systemtray--connection nil
           exwm-systemtray--list nil
           exwm-systemtray--selection-owner-window nil

exwm-workspace.el

@@ -1389,16 +1389,18 @@ Return nil if FRAME is the only workspace."
     (unless (eq frame nextw)
       nextw)))
 
-(defun exwm-workspace--remove-frame-as-workspace (frame)
+(defun exwm-workspace--remove-frame-as-workspace (frame &optional quit)
   "Stop treating frame FRAME as a workspace."
   ;; TODO: restore all frame parameters (e.g. exwm-workspace, buffer-predicate,
   ;; etc)
   (exwm--log "Removing frame `%s' as workspace" frame)
+  (unless quit
     (let* ((next-frame (exwm-workspace--get-next-workspace frame))
            (following-frames (cdr (memq frame exwm-workspace--list))))
       ;; Need to remove the workspace from the list for the correct calculation of
       ;; indexes below.
       (setq exwm-workspace--list (delete frame exwm-workspace--list))
+      ;; Move the windows to the next workspace and switch to it.
       (unless next-frame
         ;; The user managed to delete the last workspace, so create a new one.
         (exwm--log "Last workspace deleted; create a new one")
@@ -1414,7 +1416,7 @@ Return nil if FRAME is the only workspace."
             (exwm-workspace--set-desktop (car pair)))))
       ;; If the current workspace is deleted, switch to next one.
       (when (eq frame exwm-workspace--current)
-      (exwm-workspace-switch next-frame)))
+        (exwm-workspace-switch next-frame))))
   ;; Reparent out the frame.
   (let ((outer-id (frame-parameter frame 'exwm-outer-id)))
     (xcb:+request exwm--connection
@@ -1448,8 +1450,9 @@ Return nil if FRAME is the only workspace."
   ;; Update EWMH properties.
   (exwm-workspace--update-ewmh-props)
   ;; Update switch history.
+  (unless quit
     (setq exwm-workspace--switch-history-outdated t)
-  (run-hooks 'exwm-workspace-list-change-hook))
+    (run-hooks 'exwm-workspace-list-change-hook)))
 
 (defun exwm-workspace--on-delete-frame (frame)
   "Hook run upon `delete-frame' that tears down FRAME's configuration as a workspace."
@@ -1623,7 +1626,9 @@ applied to all subsequently created X frames."
   (setq default-minibuffer-frame nil)
   (when (frame-live-p exwm-workspace--minibuffer) ; might be already dead
     (let ((id (frame-parameter exwm-workspace--minibuffer 'exwm-outer-id)))
-      (when (and exwm-workspace--minibuffer id)
+      (when (and exwm-workspace--minibuffer id
+                 ;; Invoked from `exwm-manage--exit' upon disconnection.
+                 (slot-value exwm--connection 'connected))
         (xcb:+request exwm--connection
             (make-instance 'xcb:ReparentWindow
                            :window id
@@ -1708,10 +1713,10 @@ applied to all subsequently created X frames."
                  #'exwm-workspace--on-echo-area-clear))
   ;; Hide & reparent out all frames (save-set can't be used here since
   ;; X windows will be re-mapped).
-  (setq exwm-workspace--current nil)
+  (when (slot-value exwm--connection 'connected)
     (dolist (i exwm-workspace--list)
       (when (frame-live-p i)                    ; might be already dead
-      (exwm-workspace--remove-frame-as-workspace i)
+        (exwm-workspace--remove-frame-as-workspace i 'quit)
         (modify-frame-parameters i '((exwm-selected-window . nil)
                                      (exwm-urgency . nil)
                                      (exwm-outer-id . nil)
@@ -1719,8 +1724,10 @@ applied to all subsequently created X frames."
                                      (exwm-container . nil)
                                      ;; (internal-border-width . nil) ; integerp
                                      (fullscreen . nil)
-                                   (buffer-predicate . nil)))))
+                                     (buffer-predicate . nil))))))
   ;; Don't let dead frames linger.
+  (setq exwm-workspace--current nil)
+  (setq exwm-workspace-current-index 0)
   (setq exwm-workspace--list nil))
 
 (defun exwm-workspace--post-init ()

exwm-xim.el

@@ -754,10 +754,12 @@ Such event would be received when the client window is destroyed."
   ;; Close IMS communication connections.
   (mapc (lambda (i)
           (when (vectorp i)
-            (xcb:disconnect (elt i 0))))
+            (when (slot-value (elt i 0) 'connected)
+              (xcb:disconnect (elt i 0)))))
         exwm-xim--server-client-plist)
   ;; Close the IMS connection.
-  (unless exwm-xim--conn
+  (unless (and exwm-xim--conn
+               (slot-value exwm-xim--conn 'connected))
     (cl-return-from exwm-xim--exit))
   ;; Remove exwm-xim from XIM_SERVERS.
   (let ((reply (xcb:+request-unchecked+reply exwm-xim--conn

exwm.el

@@ -907,12 +907,12 @@ manager.  If t, replace it, if nil, abort and ask the user if `ask'."
   (run-hooks 'exwm-exit-hook)
   (setq confirm-kill-emacs nil)
   ;; Exit modules.
+  (when exwm--connection
     (exwm-input--exit)
     (exwm-manage--exit)
     (exwm-workspace--exit)
     (exwm-floating--exit)
     (exwm-layout--exit)
-  (when exwm--connection
     (xcb:flush exwm--connection)
     (xcb:disconnect exwm--connection))
   (setq exwm--connection nil)