Make X windows container-less

; This is an attempt to make (managed) X windows container-less, i.e. direct children of the root window.  This is mainly to make EXWM compatible with third-party compositors.  Other issues like wrong absolute position should also get resolved by the way.  The workspace containers ("virtual roots") are also removed.  However Emacs frames are still wrapped in containers to avoid unexpected stack reordering.

* exwm-cm.el: Make this module obsolete as EXWM supports third-party compositors now.

* exwm-core.el (exwm--container):
* exwm-floating.el (exwm-floating--set-floating)
(exwm-floating--unset-floating, exwm-floating-hide)
(exwm-floating--start-moveresize, exwm-floating--stop-moveresize)
(exwm-floating--do-moveresize, exwm-floating-move):
* exwm-input.el (exwm-input--update-focus):
* exwm-layout.el (exwm-layout--show, exwm-layout--hide)
(exwm-layout-set-fullscreen, exwm-layout-unset-fullscreen):
* exwm-manage.el (exwm-manage--manage-window, exwm-manage--unmanage-window)
(exwm-manage--kill-buffer-query-function, exwm-manage--kill-client):
* exwm-workspace.el (exwm-workspace--set-fullscreen, exwm-workspace-switch)
(exwm-workspace-move-window, exwm-workspace--add-frame-as-workspace)
(exwm-workspace--remove-frame-as-workspace): Make adaptions for container-less X windows.

* exwm-workspace.el (exwm-workspace--update-ewmh-props):
* exwm.el (exwm--init-icccm-ewmh, exwm--exit-icccm-ewmh): No longer use virtual roots.

* exwm-input.el (exwm-input--on-workspace-list-change)
(exwm-input--update-global-prefix-keys, exwm-input--init, exwm-input--exit): From now on global key bindings are grabbed on the root window so it's no long required to re-grab them each time the workspace list changes.  As a result `exwm-input--on-workspace-list-change' and its corresponding references are discarded.  It remains to be seen if this change will raise input focus issues.

* exwm-manage.el (exwm-manage--manage-window): Explicitly set the workspace for newly managed X windows.
* exwm-floating.el (exwm-floating--set-floating): Avoid implicit reference to the current workspace.

* exwm-core.el (exwm--set-geometry): New function for setting the geometry of an X window.
* exwm-layout.el (exwm-layout--resize-container): Replaced by `exwm-layout--resize-container'.

* exwm-core.el (exwm--guide-window): New global variable recording the guide X window.
* exwm.el (exwm--init-icccm-ewmh): Set it.

* exwm-input.el (exwm-input--post-init): New function containing staffs for initialization but should better get called after the event loop starts.
* exwm.el (exwm-init): Use it.

1 files changed, 21 insertions, 124 deletions

diff --git a/exwm-manage.el b/exwm-manage.el
index 97c9d8e3e202..0a9d92fc024b 100644
--- a/exwm-manage.el
+++ b/exwm-manage.el
@@ -92,8 +92,6 @@ corresponding buffer.")
                      :window exwm--root
                      :data (vconcat (mapcar #'car exwm--id-buffer-alist)))))
 
-(defvar exwm-floating--border-colormap)
-(defvar exwm-floating--border-pixel)
 (defvar exwm-workspace--current)
 (defvar exwm-workspace--switch-history-outdated)
 (defvar exwm-workspace-current-index)
@@ -137,7 +135,8 @@ corresponding buffer.")
       (setq exwm--id-buffer-alist
             (nconc exwm--id-buffer-alist `((,id . ,(current-buffer)))))
       (exwm-mode)
-      (setq exwm--id id)
+      (setq exwm--id id
+            exwm--frame exwm-workspace--current)
       (exwm--update-window-type id)
       (exwm--update-class id)
       (exwm--update-transient-for id)
@@ -180,38 +179,13 @@ corresponding buffer.")
         (xcb:+request exwm--connection
             (make-instance 'xcb:MapWindow :window id))
         (with-slots (x y width height) exwm--geometry
-          ;; Reparent to virtual root
-          (unless (or (memq xcb:Atom:_NET_WM_WINDOW_TYPE_DESKTOP
-                            exwm-window-type)
-                      (memq xcb:Atom:_NET_WM_WINDOW_TYPE_DOCK
-                            exwm-window-type))
-            (let ((workspace (frame-parameter exwm-workspace--current
-                                              'exwm-workspace))
-                  workarea)
-              (when (and (/= x 0)
-                         (/= y 0))
-                (setq workarea (elt exwm-workspace--workareas
-                                    exwm-workspace-current-index)
-                      x (- x (aref workarea 0))
-                      y (- y (aref workarea 1))))
-              (xcb:+request exwm--connection
-                  (make-instance 'xcb:ReparentWindow
-                                 :window id
-                                 :parent workspace
-                                 :x x :y y))))
           ;; Center window of type _NET_WM_WINDOW_TYPE_SPLASH
           (when (memq xcb:Atom:_NET_WM_WINDOW_TYPE_SPLASH exwm-window-type)
-            (xcb:+request exwm--connection
-                (make-instance 'xcb:ConfigureWindow
-                               :window id
-                               :value-mask (eval-when-compile
-                                             (logior xcb:ConfigWindow:X
-                                                     xcb:ConfigWindow:Y))
-                               :x (/ (- (exwm-workspace--current-width) width)
-                                     2)
-                               :y (/ (- (exwm-workspace--current-height)
-                                        height)
-                                     2)))))
+            (exwm--set-geometry id
+                                (/ (- (exwm-workspace--current-width) width) 2)
+                                (/ (- (exwm-workspace--current-height) height)
+                                   2)
+                                nil nil)))
         ;; Check for desktop.
         (when (memq xcb:Atom:_NET_WM_WINDOW_TYPE_DESKTOP exwm-window-type)
           ;; There should be only one desktop X window.
@@ -229,41 +203,6 @@ corresponding buffer.")
         (throw 'return 'ignored))
       ;; Manage the window
       (exwm--log "Manage #x%x" id)
-      ;; Create a new container as the parent of this X window
-      (setq exwm--container (xcb:generate-id exwm--connection))
-      (xcb:+request exwm--connection
-          (make-instance 'xcb:CreateWindow
-                         :depth 0
-                         :wid exwm--container
-                         :parent (frame-parameter exwm-workspace--current
-                                                  'exwm-workspace)
-                         :x 0
-                         :y 0
-                         :width 1
-                         :height 1
-                         :border-width 0
-                         :class xcb:WindowClass:InputOutput
-                         :visual 0
-                         :value-mask (logior xcb:CW:BackPixmap
-                                             (if exwm-floating--border-pixel
-                                                 xcb:CW:BorderPixel 0)
-                                             xcb:CW:OverrideRedirect
-                                             xcb:CW:EventMask
-                                             (if exwm-floating--border-colormap
-                                                 xcb:CW:Colormap 0))
-                         :background-pixmap xcb:BackPixmap:ParentRelative
-                         :border-pixel exwm-floating--border-pixel
-                         :override-redirect 1
-                         :event-mask xcb:EventMask:SubstructureRedirect
-                         :colormap exwm-floating--border-colormap))
-      (exwm--debug
-       (xcb:+request exwm--connection
-           (make-instance 'xcb:ewmh:set-_NET_WM_NAME
-                          :window exwm--container
-                          :data (format "EXWM container for 0x%x" id))))
-      (xcb:+request exwm--connection
-          (make-instance 'xcb:ReparentWindow
-                         :window id :parent exwm--container :x 0 :y 0))
       (xcb:+request exwm--connection    ;remove border
           (make-instance 'xcb:ConfigureWindow
                          :window id :value-mask xcb:ConfigWindow:BorderWidth
@@ -340,12 +279,6 @@ manager is shutting down."
         (exwm-workspace--set-fullscreen f)))
     (when (buffer-live-p buffer)
       (with-current-buffer buffer
-        ;; Flickering seems unavoidable here if the DestroyWindow request is
-        ;; not initiated by us.
-        ;; What we can do is to hide the its container ASAP.
-        (xcb:+request exwm--connection
-            (make-instance 'xcb:UnmapWindow :window exwm--container))
-        (xcb:flush exwm--connection)
         ;; Unmap the X window.
         (xcb:+request exwm--connection
             (make-instance 'xcb:UnmapWindow :window id))
@@ -353,30 +286,10 @@ manager is shutting down."
         (setq exwm-workspace--switch-history-outdated t)
         ;;
         (when withdraw-only
-          ;; Reparent back to root
           (xcb:+request exwm--connection
               (make-instance 'xcb:ChangeWindowAttributes
                              :window id :value-mask xcb:CW:EventMask
                              :event-mask xcb:EventMask:NoEvent))
-          (let (x y geometry geometry-parent)
-            (if (not exwm--floating-frame)
-                (setq x 0 y 0)          ;the position does not matter
-              (setq geometry-parent
-                    (xcb:+request-unchecked+reply exwm--connection
-                        (make-instance 'xcb:GetGeometry
-                                       :drawable exwm--container))
-                    geometry (xcb:+request-unchecked+reply exwm--connection
-                                 (make-instance 'xcb:GetGeometry
-                                                :drawable id)))
-              (if (not (and geometry-parent geometry))
-                  (setq x 0 y 0)        ;e.g. have been destroyed
-                (setq x (+ (slot-value geometry-parent 'x)
-                           (slot-value geometry 'x))
-                      y (+ (slot-value geometry-parent 'y)
-                           (slot-value geometry 'y)))))
-            (xcb:+request exwm--connection
-                (make-instance 'xcb:ReparentWindow
-                               :window id :parent exwm--root :x x :y y)))
           ;; Delete WM_STATE property
           (xcb:+request exwm--connection
               (make-instance 'xcb:DeleteProperty
@@ -388,19 +301,20 @@ manager is shutting down."
                                :window id
                                :property xcb:Atom:_NET_WM_DESKTOP))))
         (when exwm--floating-frame
-          ;; Unmap the floating frame before destroying the containers.
-          (let ((window (frame-parameter exwm--floating-frame 'exwm-outer-id)))
+          ;; Unmap the floating frame before destroying its container.
+          (let ((window (frame-parameter exwm--floating-frame 'exwm-outer-id))
+                (container (frame-parameter exwm--floating-frame
+                                            'exwm-container)))
             (xcb:+request exwm--connection
                 (make-instance 'xcb:UnmapWindow :window window))
             (xcb:+request exwm--connection
                 (make-instance 'xcb:ReparentWindow
-                               :window window :parent exwm--root :x 0 :y 0))))
+                               :window window :parent exwm--root :x 0 :y 0))
+            (xcb:+request exwm--connection
+                (make-instance 'xcb:DestroyWindow :window container))))
         ;; Restore the workspace if this X window is currently fullscreen.
         (when (memq xcb:Atom:_NET_WM_STATE_FULLSCREEN exwm--ewmh-state)
           (exwm-workspace--set-fullscreen exwm--frame))
-        ;; Destroy the X window container (and the frame container if any).
-        (xcb:+request exwm--connection
-            (make-instance 'xcb:DestroyWindow :window exwm--container))
         (exwm-manage--set-client-list)
         (xcb:flush exwm--connection))
       (let ((kill-buffer-func
@@ -444,38 +358,28 @@ manager is shutting down."
   "Run in `kill-buffer-query-functions'."
   (catch 'return
     (when (or (not exwm--id)
-              (not exwm--container)
               (xcb:+request-checked+request-check exwm--connection
                   (make-instance 'xcb:MapWindow
                                  :window exwm--id)))
       ;; The X window is no longer alive so just close the buffer.
-      ;; Destroy the container.
-      ;; Hide the container to prevent flickering.
-      (when exwm--container
-        (xcb:+request exwm--connection
-            (make-instance 'xcb:UnmapWindow
-                           :window exwm--container))
-        (xcb:flush exwm--connection))
       (when exwm--floating-frame
-        (let ((window (frame-parameter exwm--floating-frame 'exwm-outer-id)))
+        (let ((window (frame-parameter exwm--floating-frame 'exwm-outer-id))
+              (container (frame-parameter exwm--floating-frame
+                                          'exwm-container)))
           (xcb:+request exwm--connection
               (make-instance 'xcb:UnmapWindow :window window))
           (xcb:+request exwm--connection
               (make-instance 'xcb:ReparentWindow
                              :window window
                              :parent exwm--root
-                             :x 0 :y 0))))
-      (when exwm--container
-        (xcb:+request exwm--connection
-            (make-instance 'xcb:DestroyWindow
-                           :window exwm--container)))
+                             :x 0 :y 0))
+          (xcb:+request exwm--connection
+              (make-instance 'xcb:DestroyWindow
+                             :window container))))
       (xcb:flush exwm--connection)
       (throw 'return t))
     (unless (memq xcb:Atom:WM_DELETE_WINDOW exwm--protocols)
       ;; The X window does not support WM_DELETE_WINDOW; destroy it.
-      ;; Hide the container to prevent flickering.
-      (xcb:+request exwm--connection
-          (make-instance 'xcb:UnmapWindow :window exwm--container))
       (xcb:+request exwm--connection
           (make-instance 'xcb:DestroyWindow :window exwm--id))
       (xcb:flush exwm--connection)
@@ -529,13 +433,6 @@ Would you like to kill it? "
 (defun exwm-manage--kill-client (&optional id)
   "Kill an X client."
   (unless id (setq id (exwm--buffer->id (current-buffer))))
-  ;; Hide the container to prevent flickering.
-  (let ((buffer (exwm--id->buffer id)))
-    (when buffer
-      (with-current-buffer buffer
-        (xcb:+request exwm--connection
-            (make-instance 'xcb:UnmapWindow :window exwm--container))
-        (xcb:flush exwm--connection))))
   (let* ((response (xcb:+request-unchecked+reply exwm--connection
                        (make-instance 'xcb:ewmh:get-_NET_WM_PID :window id)))
          (pid (and response (slot-value response 'value)))