exwm/exwm-workspace.el

;;; exwm-workspace.el --- Workspace Module for EXWM  -*- lexical-binding: t -*-

;; Copyright (C) 2015-2018 Free Software Foundation, Inc.

;; Author: Chris Feng <chris.w.feng@gmail.com>

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This module adds workspace support for EXWM.

;;; Code:

(require 'server)

(require 'exwm-core)

(defgroup exwm-workspace nil
  "Workspace."
  :version "25.3"
  :group 'exwm)

(defcustom exwm-workspace-switch-hook nil
  "Normal hook run after switching workspace."
  :type 'hook)

(defcustom exwm-workspace-list-change-hook nil
  "Normal hook run when the workspace list is changed (workspace added,
deleted, moved, etc)."
  :type 'hook)

(defcustom exwm-workspace-show-all-buffers nil
  "Non-nil to show buffers on other workspaces."
  :type 'boolean)

(defcustom exwm-workspace-warp-cursor nil
  "Non-nil to warp cursor automatically after workspace switch."
  :type 'boolean)

(defcustom exwm-workspace-number 1
  "Initial number of workspaces."
  :type 'integer)

(defcustom exwm-workspace-index-map #'number-to-string
  "Function for mapping a workspace index to a string for display.

By default `number-to-string' is applied which yields 0 1 2 ... ."
  :type 'function)

(defcustom exwm-workspace-minibuffer-position nil
  "Position of the minibuffer frame."
  :type '(choice (const :tag "Bottom (fixed)" nil)
                 (const :tag "Bottom (auto-hide)" bottom)
                 (const :tag "Top (auto-hide)" top)))

(defcustom exwm-workspace-display-echo-area-timeout 1
  "Timeout for displaying echo area."
  :type 'integer)

(defcustom exwm-workspace-switch-create-limit 10
  "Number of workspaces `exwm-workspace-switch-create' allowed to create
each time."
  :type 'integer)

(defvar exwm-workspace-current-index 0 "Index of current active workspace.")

(defvar exwm-workspace--attached-minibuffer-height 0
  "Height (in pixel) of the attached minibuffer.

If the minibuffer is detached, this value is 0.")

(defvar exwm-workspace--client nil
  "The 'client' frame parameter of emacsclient frames.")

(defvar exwm-workspace--create-silently nil
  "When non-nil workspaces are created in the background (not switched to).

Please manually run the hook `exwm-workspace-list-change-hook' afterwards.")

(defvar exwm-workspace--current nil "Current active workspace.")

(defvar exwm-workspace--display-echo-area-timer nil
  "Timer for auto-hiding echo area.")

(defvar exwm-workspace--id-struts-alist nil "Alist of X window and struts.")

(defvar exwm-workspace--fullscreen-frame-count 0
  "Count the fullscreen workspace frames.")

(defvar exwm-workspace--list nil "List of all workspaces (Emacs frames).")

(defvar exwm-workspace--minibuffer nil
  "The minibuffer frame shared among all frames.")

(defvar exwm-workspace--prompt-add-allowed nil
  "Non-nil to allow adding workspace from the prompt.")

(defvar exwm-workspace--prompt-delete-allowed nil
  "Non-nil to allow deleting workspace from the prompt.")

(defvar exwm-workspace--struts nil "Areas occupied by struts.")

(defvar exwm-workspace--switch-history nil
  "History for `read-from-minibuffer' to interactively switch workspace.")

(defvar exwm-workspace--switch-history-outdated nil
  "Non-nil to indicate `exwm-workspace--switch-history' is outdated.")

(defvar exwm-workspace--timer nil "Timer used to track echo area changes.")

(defvar exwm-workspace--update-workareas-hook nil
  "Normal hook run when workareas get updated.")

(defvar exwm-workspace--workareas nil "Workareas (struts excluded).")

(defvar exwm-input--during-command)
(defvar exwm-input--event-hook)
(defvar exwm-layout-show-all-buffers)
(defvar exwm-manage--desktop)
(declare-function exwm-input--on-buffer-list-update "exwm-input.el" ())
(declare-function exwm-layout--fullscreen-p "exwm-layout.el" ())
(declare-function exwm-layout--hide "exwm-layout.el" (id))
(declare-function exwm-layout--other-buffer-predicate "exwm-layout.el"
                  (buffer))
(declare-function exwm-layout--refresh "exwm-layout.el")
(declare-function exwm-layout--show "exwm-layout.el" (id &optional window))

(defsubst exwm-workspace--position (frame)
  "Retrieve index of given FRAME in workspace list.

NIL if FRAME is not a workspace"
  (cl-position frame exwm-workspace--list))

(defsubst exwm-workspace--count ()
  "Retrieve total number of workspaces."
  (length exwm-workspace--list))

(defsubst exwm-workspace--workspace-p (frame)
  "Return t if FRAME is a workspace."
  (memq frame exwm-workspace--list))

(defsubst exwm-workspace--client-p (&optional frame)
  "Return non-nil if FRAME is an emacsclient frame."
  (frame-parameter frame 'client))

(defvar exwm-workspace--switch-map
  (let ((map (make-sparse-keymap)))
    (define-key map [t] (lambda () (interactive)))
    (define-key map "+" #'exwm-workspace--prompt-add)
    (define-key map "-" #'exwm-workspace--prompt-delete)
    (dotimes (i 10)
      (define-key map (int-to-string i)
        #'exwm-workspace--switch-map-nth-prefix))
    (define-key map "\C-a" (lambda () (interactive) (goto-history-element 1)))
    (define-key map "\C-e" (lambda ()
                             (interactive)
                             (goto-history-element (exwm-workspace--count))))
    (define-key map "\C-g" #'abort-recursive-edit)
    (define-key map "\C-]" #'abort-recursive-edit)
    (define-key map "\C-j" #'exit-minibuffer)
    ;; (define-key map "\C-m" #'exit-minibuffer) ;not working
    (define-key map [return] #'exit-minibuffer)
    (define-key map " " #'exit-minibuffer)
    (define-key map "\C-f" #'previous-history-element)
    (define-key map "\C-b" #'next-history-element)
    ;; Alternative keys
    (define-key map [right] #'previous-history-element)
    (define-key map [left] #'next-history-element)
    map)
  "Keymap used for interactively switch workspace.")

(defun exwm-workspace--workspace-from-frame-or-index (frame-or-index)
  "Retrieve the workspace frame from FRAME-OR-INDEX."
  (cond
   ((framep frame-or-index)
    (unless (exwm-workspace--position frame-or-index)
      (user-error "[EXWM] Frame is not a workspace %S" frame-or-index))
    frame-or-index)
   ((integerp frame-or-index)
    (unless (and (<= 0 frame-or-index)
                 (< frame-or-index (exwm-workspace--count)))
      (user-error "[EXWM] Workspace index out of range: %d" frame-or-index))
    (elt exwm-workspace--list frame-or-index))
   (t (user-error "[EXWM] Invalid workspace: %s" frame-or-index))))

(defun exwm-workspace--prompt-for-workspace (&optional prompt)
  "Prompt for a workspace, returning the workspace frame."
  (exwm-workspace--update-switch-history)
  (let* ((current-idx (exwm-workspace--position exwm-workspace--current))
         (history-add-new-input nil)  ;prevent modifying history
         (history-idx (read-from-minibuffer
                       (or prompt "Workspace: ")
                       (elt exwm-workspace--switch-history current-idx)
                       exwm-workspace--switch-map nil
                       `(exwm-workspace--switch-history . ,(1+ current-idx))))
         (workspace-idx (cl-position history-idx exwm-workspace--switch-history
                                     :test #'equal)))
    (elt exwm-workspace--list workspace-idx)))

(defun exwm-workspace--prompt-add ()
  "Add workspace from the prompt."
  (interactive)
  (when exwm-workspace--prompt-add-allowed
    (let ((exwm-workspace--create-silently t))
      (make-frame)
      (run-hooks 'exwm-workspace-list-change-hook))
    (exwm-workspace--update-switch-history)
    (goto-history-element minibuffer-history-position)))

(defun exwm-workspace--prompt-delete ()
  "Delete workspace from the prompt."
  (interactive)
  (when (and exwm-workspace--prompt-delete-allowed
             (< 1 (exwm-workspace--count)))
    (let ((frame (elt exwm-workspace--list (1- minibuffer-history-position))))
      (if (eq frame exwm-workspace--current)
          ;; Abort the recursive minibuffer if deleting the current workspace.
          (progn
            (exwm--defer 0 #'delete-frame frame)
            (abort-recursive-edit))
        (delete-frame frame)
        (exwm-workspace--update-switch-history)
        (goto-history-element (min minibuffer-history-position
                                   (exwm-workspace--count)))))))

(defun exwm-workspace--update-switch-history ()
  "Update the history for switching workspace to reflect the latest status."
  (when exwm-workspace--switch-history-outdated
    (setq exwm-workspace--switch-history-outdated nil)
    (let* ((num (exwm-workspace--count))
           (sequence (number-sequence 0 (1- num)))
           (not-empty (make-vector num nil)))
      (dolist (i exwm--id-buffer-alist)
        (with-current-buffer (cdr i)
          (when exwm--frame
            (setf (aref not-empty
                        (exwm-workspace--position exwm--frame))
                  t))))
      (setq exwm-workspace--switch-history
            (mapcar
             (lambda (i)
               (mapconcat
                (lambda (j)
                  (format (if (= i j) "[%s]" " %s ")
                          (propertize
                           (apply exwm-workspace-index-map (list j))
                           'face
                           (cond ((frame-parameter (elt exwm-workspace--list j)
                                                   'exwm-urgency)
                                  '(:foreground "orange"))
                                 ((aref not-empty j) '(:foreground "green"))
                                 (t nil)))))
                sequence ""))
             sequence)))))

;;;###autoload
(defun exwm-workspace--get-geometry (frame)
  "Return the geometry of frame FRAME."
  (or (frame-parameter frame 'exwm-geometry)
      (make-instance 'xcb:RECTANGLE
                     :x 0
                     :y 0
                     :width (x-display-pixel-width)
                     :height (x-display-pixel-height))))

;;;###autoload
(defun exwm-workspace--current-height ()
  "Return the height of current workspace."
  (let ((geometry (frame-parameter exwm-workspace--current 'exwm-geometry)))
    (if geometry
        (slot-value geometry 'height)
      (x-display-pixel-height))))

;;;###autoload
(defun exwm-workspace--minibuffer-own-frame-p ()
  "Reports whether the minibuffer is displayed in its own frame."
  (memq exwm-workspace-minibuffer-position '(top bottom)))

(defun exwm-workspace--update-struts ()
  "Update `exwm-workspace--struts'."
  (setq exwm-workspace--struts nil)
  (let (struts struts*)
    (dolist (pair exwm-workspace--id-struts-alist)
      (setq struts (cdr pair))
      (when struts
        (dotimes (i 4)
          (when (/= 0 (aref struts i))
            (setq struts*
                  (vector (aref [left right top bottom] i)
                          (aref struts i)
                          (when (= 12 (length struts))
                            (substring struts (+ 4 (* i 2)) (+ 6 (* i 2))))))
            (if (= 0 (mod i 2))
                ;; Make left/top processed first.
                (push struts* exwm-workspace--struts)
              (setq exwm-workspace--struts
                    (append exwm-workspace--struts (list struts*))))))))))

(defun exwm-workspace--update-workareas ()
  "Update `exwm-workspace--workareas'."
  (let ((root-width (x-display-pixel-width))
        (root-height (x-display-pixel-height))
        workareas
        edge width position
        delta)
    ;; Calculate workareas with no struts.
    (if (frame-parameter (car exwm-workspace--list) 'exwm-geometry)
        ;; Use the 'exwm-geometry' frame parameter if possible.
        (dolist (f exwm-workspace--list)
          (with-slots (x y width height) (frame-parameter f 'exwm-geometry)
            (setq workareas (append workareas
                                    (list (vector x y width height))))))
      ;; Fall back to use the screen size.
      (let ((workarea (vector 0 0 root-width root-height)))
        (setq workareas (make-list (exwm-workspace--count) workarea))))
    ;; Exclude areas occupied by struts.
    (dolist (struts exwm-workspace--struts)
      (setq edge (aref struts 0)
            width (aref struts 1)
            position (aref struts 2))
      (dolist (w workareas)
        (pcase edge
          ;; Left and top are always processed first.
          (`left
           (setq delta (- (aref w 0) width))
           (when (and (< delta 0)
                      (or (not position)
                          (< (max (aref position 0) (aref w 1))
                             (min (aref position 1)
                                  (+ (aref w 1) (aref w 3))))))
             (cl-incf (aref w 2) delta)
             (setf (aref w 0) width)))
          (`right
           (setq delta (- root-width (aref w 0) (aref w 2) width))
           (when (and (< delta 0)
                      (or (not position)
                          (< (max (aref position 0) (aref w 1))
                             (min (aref position 1)
                                  (+ (aref w 1) (aref w 3))))))
             (cl-incf (aref w 2) delta)))
          (`top
           (setq delta (- (aref w 1) width))
           (when (and (< delta 0)
                      (or (not position)
                          (< (max (aref position 0) (aref w 0))
                             (min (aref position 1)
                                  (+ (aref w 0) (aref w 2))))))
             (cl-incf (aref w 3) delta)
             (setf (aref w 1) width)))
          (`bottom
           (setq delta (- root-height (aref w 1) (aref w 3) width))
           (when (and (< delta 0)
                      (or (not position)
                          (< (max (aref position 0) (aref w 0))
                             (min (aref position 1)
                                  (+ (aref w 0) (aref w 2))))))
             (cl-incf (aref w 3) delta))))))
    ;; Save the result.
    (setq exwm-workspace--workareas workareas)
    (xcb:flush exwm--connection))
  (run-hooks 'exwm-workspace--update-workareas-hook))

(defun exwm-workspace--set-active (frame active)
  "Make frame FRAME active on its output."
  (exwm--log "active=%s; frame=%s" frame active)
  (set-frame-parameter frame 'exwm-active active)
  (if active
      (exwm-workspace--set-fullscreen frame)
    (exwm--set-geometry (frame-parameter frame 'exwm-container) nil nil 1 1))
  (exwm-layout--refresh frame)
  (xcb:flush exwm--connection))

(defun exwm-workspace--active-p (frame)
  "Return non-nil if FRAME is active"
  (frame-parameter frame 'exwm-active))

(defun exwm-workspace--set-fullscreen (frame)
  "Make frame FRAME fullscreen according to `exwm-workspace--workareas'."
  (exwm--log "frame=%s" frame)
  (let ((workarea (elt exwm-workspace--workareas
                       (exwm-workspace--position frame)))
        (id (frame-parameter frame 'exwm-outer-id))
        (container (frame-parameter frame 'exwm-container))
        x y width height)
    (setq x (aref workarea 0)
          y (aref workarea 1)
          width (aref workarea 2)
          height (aref workarea 3))
    (exwm--log "x=%s; y=%s; w=%s; h=%s" x y width height)
    (when (and (eq frame exwm-workspace--current)
               (exwm-workspace--minibuffer-own-frame-p))
      (exwm-workspace--resize-minibuffer-frame))
    (if (exwm-workspace--active-p frame)
        (exwm--set-geometry container x y width height)
      (exwm--set-geometry container x y 1 1))
    (exwm--set-geometry id nil nil width height)
    (xcb:flush exwm--connection))
  ;; This is only used for workspace initialization.
  (when exwm-workspace--fullscreen-frame-count
    (cl-incf exwm-workspace--fullscreen-frame-count)))

(defun exwm-workspace--resize-minibuffer-frame ()
  "Resize minibuffer (and its container) to fit the size of workspace."
  (cl-assert (exwm-workspace--minibuffer-own-frame-p))
  (let ((workarea (elt exwm-workspace--workareas exwm-workspace-current-index))
        (container (frame-parameter exwm-workspace--minibuffer
                                    'exwm-container))
        y width)
    (setq y (if (eq exwm-workspace-minibuffer-position 'top)
                (- (aref workarea 1)
                   exwm-workspace--attached-minibuffer-height)
              ;; Reset the frame size.
              (set-frame-height exwm-workspace--minibuffer 1)
              (redisplay)               ;FIXME.
              (+ (aref workarea 1) (aref workarea 3)
                 (- (frame-pixel-height exwm-workspace--minibuffer))
                 exwm-workspace--attached-minibuffer-height))
          width (aref workarea 2))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ConfigureWindow
                       :window container
                       :value-mask (logior xcb:ConfigWindow:X
                                           xcb:ConfigWindow:Y
                                           xcb:ConfigWindow:Width
                                           (if exwm-manage--desktop
                                               xcb:ConfigWindow:Sibling
                                             0)
                                           xcb:ConfigWindow:StackMode)
                       :x (aref workarea 0)
                       :y y
                       :width width
                       :sibling exwm-manage--desktop
                       :stack-mode (if exwm-manage--desktop
                                       xcb:StackMode:Above
                                     xcb:StackMode:Below)))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ConfigureWindow
                       :window (frame-parameter exwm-workspace--minibuffer
                                                'exwm-outer-id)
                       :value-mask xcb:ConfigWindow:Width
                       :width width))))

(defun exwm-workspace--switch-map-nth-prefix (&optional prefix-digits)
  "Allow selecting a workspace by number.

PREFIX-DIGITS is a list of the digits introduced so far."
  (interactive)
  (let* ((k (aref (substring (this-command-keys-vector) -1) 0))
         (d (- k ?0))
         ;; Convert prefix-digits to number.  For example, '(2 1) to 120.
         (o 1)
         (pn (apply #'+ (mapcar (lambda (x)
                                  (setq o (* 10 o))
                                  (* o x))
                                prefix-digits)))
         (n (+ pn d))
         prefix-length index-max index-length)
    (if (or (= n 0)
            (> n
               (setq index-max (1- (exwm-workspace--count))))
            (>= (setq prefix-length (length prefix-digits))
                (setq index-length (floor (log index-max 10))))
            ;; Check if it's still possible to do a match.
            (> (* n (expt 10 (- index-length prefix-length)))
               index-max))
        (exwm-workspace--switch-map-select-nth n)
      ;; Go ahead if there are enough digits to select any workspace.
      (set-transient-map
       (let ((map (make-sparse-keymap))
             (cmd `(lambda ()
                     (interactive)
                     (exwm-workspace--switch-map-nth-prefix
                      ',(cons d prefix-digits)))))
         (dotimes (i 10)
           (define-key map (int-to-string i) cmd))
         ;; Accept
         (define-key map [return]
           `(lambda ()
              (interactive)
              (exwm-workspace--switch-map-select-nth ,n)))
         map)))))

(defun exwm-workspace--switch-map-select-nth (n)
  "Select Nth workspace."
  (interactive)
  (goto-history-element (1+ n))
  (exit-minibuffer))

;;;###autoload
(defun exwm-workspace-switch (frame-or-index &optional force)
  "Switch to workspace INDEX (0-based).

Query for the index if not specified when called interactively.  Passing a
workspace frame as the first option or making use of the rest options are
for internal use only."
  (interactive
   (list
    (cond
     ((null current-prefix-arg)
      (unless (and (derived-mode-p 'exwm-mode)
                   ;; The prompt is invisible in fullscreen mode.
                   (exwm-layout--fullscreen-p))
        (let ((exwm-workspace--prompt-add-allowed t)
              (exwm-workspace--prompt-delete-allowed t))
          (exwm-workspace--prompt-for-workspace "Switch to [+/-]: "))))
     ((and (integerp current-prefix-arg)
           (<= 0 current-prefix-arg (exwm-workspace--count)))
      current-prefix-arg)
     (t 0))))
  (exwm--log)
  (let* ((frame (exwm-workspace--workspace-from-frame-or-index frame-or-index))
         (old-frame exwm-workspace--current)
         (index (exwm-workspace--position frame))
         (window (frame-parameter frame 'exwm-selected-window)))
    (when (or force (not (eq frame exwm-workspace--current)))
      (unless (window-live-p window)
        (setq window (frame-selected-window frame)))
      ;; Raise this frame.
      (xcb:+request exwm--connection
          (make-instance 'xcb:ConfigureWindow
                         :window (frame-parameter frame 'exwm-container)
                         :value-mask (logior xcb:ConfigWindow:Sibling
                                             xcb:ConfigWindow:StackMode)
                         :sibling exwm--guide-window
                         :stack-mode xcb:StackMode:Below))
      (setq exwm-workspace--current frame
            exwm-workspace-current-index index)
      (unless (exwm-workspace--workspace-p (selected-frame))
        ;; Save the floating frame window selected on the previous workspace.
        (set-frame-parameter (buffer-local-value 'exwm--frame (window-buffer))
                             'exwm-selected-window (selected-window)))
      ;; Show/Hide X windows.
      (let ((output-old (frame-parameter old-frame 'exwm-randr-output))
            (output-new (frame-parameter frame 'exwm-randr-output))
            (active-old (exwm-workspace--active-p old-frame))
            (active-new (exwm-workspace--active-p frame))
            workspaces-to-hide)
        (cond
         ((not active-old)
          (exwm-workspace--set-active frame t))
         ((equal output-old output-new)
          (exwm-workspace--set-active frame t)
          (unless (eq frame old-frame)
            (exwm-workspace--set-active old-frame nil)
            (setq workspaces-to-hide (list old-frame))))
         (active-new)
         (t
          (dolist (w exwm-workspace--list)
            (when (and (exwm-workspace--active-p w)
                       (equal output-new
                              (frame-parameter w 'exwm-randr-output)))
              (exwm-workspace--set-active w nil)
              (setq workspaces-to-hide (append workspaces-to-hide (list w)))))
          (exwm-workspace--set-active frame t)))
        (dolist (i exwm--id-buffer-alist)
          (with-current-buffer (cdr i)
            (if (memq exwm--frame workspaces-to-hide)
                (exwm-layout--hide exwm--id)
              (when (eq frame exwm--frame)
                (let ((window (get-buffer-window nil t)))
                  (when window
                    (exwm-layout--show exwm--id window))))))))
      (select-window window)
      (x-focus-frame (window-frame window)) ;The real input focus.
      (set-frame-parameter frame 'exwm-selected-window nil)
      ;; Close the (possible) active minibuffer
      (when (active-minibuffer-window)
        (exwm--defer 0 (lambda ()
                         ;; Might be aborted by then.
                         (when (active-minibuffer-window)
                           (abort-recursive-edit)))))
      (if (exwm-workspace--minibuffer-own-frame-p)
          ;; Resize the minibuffer frame.
          (exwm-workspace--resize-minibuffer-frame)
        ;; Set a default minibuffer frame.
        (setq default-minibuffer-frame frame))
      ;; Hide windows in other workspaces by preprending a space
      (unless exwm-workspace-show-all-buffers
        (dolist (i exwm--id-buffer-alist)
          (with-current-buffer (cdr i)
            (let ((name (replace-regexp-in-string "^\\s-*" ""
                                                  (buffer-name))))
              (exwm-workspace-rename-buffer (if (eq frame exwm--frame)
                                                name
                                              (concat " " name)))))))
      ;; Update demands attention flag
      (set-frame-parameter frame 'exwm-urgency nil)
      ;; Update switch workspace history
      (setq exwm-workspace--switch-history-outdated t)
      ;; Set _NET_CURRENT_DESKTOP
      (xcb:+request exwm--connection
          (make-instance 'xcb:ewmh:set-_NET_CURRENT_DESKTOP
                         :window exwm--root :data index))
      (xcb:flush exwm--connection))
    (when exwm-workspace-warp-cursor
      (with-slots (win-x win-y)
          (xcb:+request-unchecked+reply exwm--connection
              (make-instance 'xcb:QueryPointer
                             :window (frame-parameter frame
                                                      'exwm-outer-id)))
        (when (or (< win-x 0)
                  (< win-y 0)
                  (> win-x (frame-pixel-width frame))
                  (> win-y (frame-pixel-height frame)))
          (xcb:+request exwm--connection
              (make-instance 'xcb:WarpPointer
                             :src-window xcb:Window:None
                             :dst-window (frame-parameter frame
                                                          'exwm-outer-id)
                             :src-x 0
                             :src-y 0
                             :src-width 0
                             :src-height 0
                             :dst-x (/ (frame-pixel-width frame) 2)
                             :dst-y (/ (frame-pixel-height frame) 2)))
          (xcb:flush exwm--connection))))
    (when (and (not (eq frame old-frame))
               (frame-live-p old-frame))
      (with-selected-frame old-frame
        (run-hooks 'focus-out-hook)))
    (run-hooks 'focus-in-hook)
    (run-hooks 'exwm-workspace-switch-hook)))

;;;###autoload
(defun exwm-workspace-switch-create (frame-or-index)
  "Switch to workspace INDEX or creating it first if it does not exist yet.

Passing a workspace frame as the first option is for internal use only."
  (interactive
   (list
    (cond
     ((integerp current-prefix-arg)
      current-prefix-arg)
     (t 0))))
  (unless frame-or-index
    (setq frame-or-index 0))
  (if (or (framep frame-or-index)
          (< frame-or-index (exwm-workspace--count)))
      (exwm-workspace-switch frame-or-index)
    (let ((exwm-workspace--create-silently t))
      (dotimes (_ (min exwm-workspace-switch-create-limit
                       (1+ (- frame-or-index
                              (exwm-workspace--count)))))
        (make-frame))
      (run-hooks 'exwm-workspace-list-change-hook))
    (exwm-workspace-switch frame-or-index)))

;;;###autoload
(defun exwm-workspace-swap (workspace1 workspace2)
  "Interchange position of WORKSPACE1 with that of WORKSPACE2."
  (interactive
   (unless (and (derived-mode-p 'exwm-mode)
                ;; The prompt is invisible in fullscreen mode.
                (exwm-layout--fullscreen-p))
     (let (w1 w2)
       (let ((exwm-workspace--prompt-add-allowed t)
             (exwm-workspace--prompt-delete-allowed t))
         (setq w1 (exwm-workspace--prompt-for-workspace
                   "Pick a workspace [+/-]: ")))
       (setq w2 (exwm-workspace--prompt-for-workspace
                 (format "Swap workspace %d with: "
                         (exwm-workspace--position w1))))
       (list w1 w2))))
  (exwm--log)
  (let ((pos1 (exwm-workspace--position workspace1))
        (pos2 (exwm-workspace--position workspace2)))
    (if (or (not pos1) (not pos2) (= pos1 pos2))
        (user-error "[EXWM] Cannot swap %s and %s" workspace1 workspace2)
      (setf (elt exwm-workspace--list pos1) workspace2)
      (setf (elt exwm-workspace--list pos2) workspace1)
      ;; Update the _NET_WM_DESKTOP property of each X window affected.
      (dolist (pair exwm--id-buffer-alist)
        (when (memq (buffer-local-value 'exwm--frame (cdr pair))
                    (list workspace1 workspace2))
          (exwm-workspace--set-desktop (car pair))))
      (xcb:flush exwm--connection)
      (when (memq exwm-workspace--current (list workspace1 workspace2))
        ;; With the current workspace involved, lots of stuffs need refresh.
        (set-frame-parameter exwm-workspace--current 'exwm-selected-window
                             (selected-window))
        (exwm-workspace-switch exwm-workspace--current t))
      (run-hooks 'exwm-workspace-list-change-hook))))

;;;###autoload
(defun exwm-workspace-move (workspace nth)
  "Move WORKSPACE to the NTH position.

When called interactively, prompt for a workspace and move current one just
before it."
  (interactive
   (cond
    ((null current-prefix-arg)
     (unless (and (derived-mode-p 'exwm-mode)
                  ;; The prompt is invisible in fullscreen mode.
                  (exwm-layout--fullscreen-p))
       (list exwm-workspace--current
             (exwm-workspace--position
              (exwm-workspace--prompt-for-workspace "Move workspace to: ")))))
    ((and (integerp current-prefix-arg)
          (<= 0 current-prefix-arg (exwm-workspace--count)))
     (list exwm-workspace--current current-prefix-arg))
    (t (list exwm-workspace--current 0))))
  (exwm--log)
  (let ((pos (exwm-workspace--position workspace))
        flag start end index)
    (if (= nth pos)
        (user-error "[EXWM] Cannot move to same position")
      ;; Set if the current workspace is involved.
      (setq flag (or (eq workspace exwm-workspace--current)
                     (eq (elt exwm-workspace--list nth)
                         exwm-workspace--current)))
      ;; Do the move.
      (with-no-warnings                 ;For Emacs 24.
        (pop (nthcdr pos exwm-workspace--list)))
      (push workspace (nthcdr nth exwm-workspace--list))
      ;; Update the _NET_WM_DESKTOP property of each X window affected.
      (setq start (min pos nth)
            end (max pos nth))
      (dolist (pair exwm--id-buffer-alist)
        (setq index (exwm-workspace--position
                     (buffer-local-value 'exwm--frame (cdr pair))))
        (unless (or (< index start) (> index end))
          (exwm-workspace--set-desktop (car pair))))
      (when flag
        ;; With the current workspace involved, lots of stuffs need refresh.
        (set-frame-parameter exwm-workspace--current 'exwm-selected-window
                             (selected-window))
        (exwm-workspace-switch exwm-workspace--current t))
      (run-hooks 'exwm-workspace-list-change-hook))))

;;;###autoload
(defun exwm-workspace-add (&optional index)
  "Add a workspace as the INDEX-th workspace, or the last one if INDEX is nil.

INDEX must not exceed the current number of workspaces."
  (interactive)
  (if (and index
           ;; No need to move if it's the last one.
           (< index (exwm-workspace--count)))
      (exwm-workspace-move (make-frame) index)
    (make-frame)))

;;;###autoload
(defun exwm-workspace-delete (&optional frame-or-index)
  "Delete the workspace FRAME-OR-INDEX."
  (interactive)
  (when (< 1 (exwm-workspace--count))
    (delete-frame
     (if frame-or-index
         (exwm-workspace--workspace-from-frame-or-index frame-or-index)
       exwm-workspace--current))))

(defun exwm-workspace--set-desktop (id)
  "Set _NET_WM_DESKTOP for X window ID."
  (with-current-buffer (exwm--id->buffer id)
    (let ((desktop (exwm-workspace--position exwm--frame)))
      (setq exwm--desktop desktop)
      (xcb:+request exwm--connection
          (make-instance 'xcb:ewmh:set-_NET_WM_DESKTOP
                         :window id
                         :data desktop)))))

;;;###autoload
(defun exwm-workspace-move-window (frame-or-index &optional id)
  "Move window ID to workspace FRAME-OR-INDEX."
  (interactive (list
                (cond
                 ((null current-prefix-arg)
                  (let ((exwm-workspace--prompt-add-allowed t)
                        (exwm-workspace--prompt-delete-allowed t))
                    (exwm-workspace--prompt-for-workspace "Move to [+/-]: ")))
                 ((and (integerp current-prefix-arg)
                       (<= 0 current-prefix-arg (exwm-workspace--count)))
                  current-prefix-arg)
                 (t 0))))
  (let ((frame (exwm-workspace--workspace-from-frame-or-index frame-or-index))
        old-frame container)
    (unless id (setq id (exwm--buffer->id (window-buffer))))
    (with-current-buffer (exwm--id->buffer id)
      (unless (eq exwm--frame frame)
        (unless exwm-workspace-show-all-buffers
          (let ((name (replace-regexp-in-string "^\\s-*" "" (buffer-name))))
            (exwm-workspace-rename-buffer
             (if (eq frame exwm-workspace--current)
                 name
               (concat " " name)))))
        (setq old-frame exwm--frame
              exwm--frame frame)
        (if (not exwm--floating-frame)
            ;; Tiling.
            (if (get-buffer-window nil frame)
                (when (eq frame exwm-workspace--current)
                  (run-window-configuration-change-hook frame))
              (set-window-buffer (get-buffer-window nil t)
                                 (other-buffer nil t))
              (unless (eq frame exwm-workspace--current)
                ;; Clear the 'exwm-selected-window' frame parameter.
                (set-frame-parameter frame 'exwm-selected-window nil))
              (set-window-buffer (frame-selected-window frame)
                                 (exwm--id->buffer id))
              (if (eq frame exwm-workspace--current)
                  (select-window (frame-selected-window frame))
                (unless (exwm-workspace--active-p frame)
                  (exwm-layout--hide id))))
          ;; Floating.
          (setq container (frame-parameter exwm--floating-frame
                                           'exwm-container))
          (unless (equal (frame-parameter old-frame 'exwm-randr-output)
                         (frame-parameter frame 'exwm-randr-output))
            (with-slots (x y)
                (xcb:+request-unchecked+reply exwm--connection
                    (make-instance 'xcb:GetGeometry
                                   :drawable container))
              (with-slots ((x1 x)
                           (y1 y))
                  (exwm-workspace--get-geometry old-frame)
                (with-slots ((x2 x)
                             (y2 y))
                    (exwm-workspace--get-geometry frame)
                  (setq x (+ x (- x2 x1))
                        y (+ y (- y2 y1)))))
              (exwm--set-geometry id x y nil nil)
              (exwm--set-geometry container x y nil nil)))
          (if (exwm-workspace--minibuffer-own-frame-p)
              (if (eq frame exwm-workspace--current)
                  (select-window (frame-root-window exwm--floating-frame))
                (select-window (frame-selected-window exwm-workspace--current))
                (unless (exwm-workspace--active-p frame)
                  (exwm-layout--hide id)))
            ;; The frame needs to be recreated since it won't use the
            ;; minibuffer on the new workspace.
            ;; The code is mostly copied from `exwm-floating--set-floating'.
            (let* ((old-frame exwm--floating-frame)
                   (new-frame
                    (with-current-buffer
                        (or (get-buffer "*scratch*")
                            (progn
                              (set-buffer-major-mode
                               (get-buffer-create "*scratch*"))
                              (get-buffer "*scratch*")))
                      (make-frame
                       `((minibuffer . ,(minibuffer-window frame))
                         (left . ,(* window-min-width -100))
                         (top . ,(* window-min-height -100))
                         (width . ,window-min-width)
                         (height . ,window-min-height)
                         (unsplittable . t)))))
                   (outer-id (string-to-number
                              (frame-parameter new-frame
                                               'outer-window-id)))
                   (window-id (string-to-number
                               (frame-parameter new-frame 'window-id)))
                   (window (frame-root-window new-frame)))
              (set-frame-parameter new-frame 'exwm-outer-id outer-id)
              (set-frame-parameter new-frame 'exwm-id window-id)
              (set-frame-parameter new-frame 'exwm-container container)
              (make-frame-invisible new-frame)
              (set-frame-size new-frame
                              (frame-pixel-width old-frame)
                              (frame-pixel-height old-frame)
                              t)
              (xcb:+request exwm--connection
                  (make-instance 'xcb:ReparentWindow
                                 :window outer-id
                                 :parent container
                                 :x 0 :y 0))
              (xcb:flush exwm--connection)
              (with-current-buffer (exwm--id->buffer id)
                (setq window-size-fixed nil
                      exwm--floating-frame new-frame)
                (set-window-dedicated-p (frame-root-window old-frame) nil)
                (remove-hook 'window-configuration-change-hook
                             #'exwm-layout--refresh)
                (set-window-buffer window (current-buffer))
                (add-hook 'window-configuration-change-hook
                          #'exwm-layout--refresh)
                (set-window-dedicated-p window t))
              ;; Select a tiling window and delete the old frame.
              (select-window (frame-selected-window exwm-workspace--current))
              (delete-frame old-frame)
              ;; The rest is the same.
              (make-frame-visible new-frame)
              (exwm--set-geometry outer-id 0 0 nil nil)
              (xcb:flush exwm--connection)
              (redisplay)
              (if (eq frame exwm-workspace--current)
                  (with-current-buffer (exwm--id->buffer id)
                    (select-window (frame-root-window exwm--floating-frame)))
                (unless (exwm-workspace--active-p frame)
                  (exwm-layout--hide id)))))
          ;; Update the 'exwm-selected-window' frame parameter.
          (when (not (eq frame exwm-workspace--current))
            (with-current-buffer (exwm--id->buffer id)
              (set-frame-parameter frame 'exwm-selected-window
                                   (frame-root-window
                                    exwm--floating-frame)))))
        ;; Set _NET_WM_DESKTOP.
        (exwm-workspace--set-desktop id)
        (xcb:flush exwm--connection)))
    (setq exwm-workspace--switch-history-outdated t)))

;;;###autoload
(defun exwm-workspace-switch-to-buffer (buffer-or-name)
  "Make the current Emacs window display another buffer."
  (interactive
   (let ((inhibit-quit t))
     ;; Show all buffers
     (unless exwm-workspace-show-all-buffers
       (dolist (pair exwm--id-buffer-alist)
         (with-current-buffer (cdr pair)
           (when (= ?\s (aref (buffer-name) 0))
             (let ((buffer-list-update-hook
                    (remq #'exwm-input--on-buffer-list-update
                          buffer-list-update-hook)))
               (rename-buffer (substring (buffer-name) 1)))))))
     (prog1
         (with-local-quit
           (list (get-buffer (read-buffer-to-switch "Switch to buffer: "))))
       ;; Hide buffers on other workspaces
       (unless exwm-workspace-show-all-buffers
         (dolist (pair exwm--id-buffer-alist)
           (with-current-buffer (cdr pair)
             (unless (or (eq exwm--frame exwm-workspace--current)
                         (= ?\s (aref (buffer-name) 0)))
               (let ((buffer-list-update-hook
                      (remq #'exwm-input--on-buffer-list-update
                            buffer-list-update-hook)))
                 (rename-buffer (concat " " (buffer-name)))))))))))
  (exwm--log)
  (when buffer-or-name
    (with-current-buffer buffer-or-name
      (if (derived-mode-p 'exwm-mode)
          ;; EXWM buffer.
          (if (eq exwm--frame exwm-workspace--current)
              ;; On the current workspace.
              (if (not exwm--floating-frame)
                  (switch-to-buffer buffer-or-name)
                ;; Select the floating frame.
                (select-frame-set-input-focus exwm--floating-frame)
                (select-window (frame-root-window exwm--floating-frame)))
            ;; On another workspace.
            (if exwm-layout-show-all-buffers
                (exwm-workspace-move-window exwm-workspace--current
                                            exwm--id)
              (let ((window (get-buffer-window buffer-or-name exwm--frame)))
                (if window
                    (set-frame-parameter exwm--frame
                                         'exwm-selected-window window)
                  (set-window-buffer (frame-selected-window exwm--frame)
                                     buffer-or-name)))
              (exwm-workspace-switch exwm--frame)))
        ;; Ordinary buffer.
        (switch-to-buffer buffer-or-name)))))

(defun exwm-workspace-rename-buffer (newname)
  "Rename a buffer."
  (let ((hidden (= ?\s (aref newname 0)))
        (basename (replace-regexp-in-string "<[0-9]+>$" "" newname))
        (counter 1)
        tmp)
    (when hidden (setq basename (substring basename 1)))
    (setq newname basename)
    (while (and (setq tmp (or (get-buffer newname)
                              (get-buffer (concat " " newname))))
                (not (eq tmp (current-buffer))))
      (setq newname (format "%s<%d>" basename (cl-incf counter))))
    (let ((buffer-list-update-hook
           (remq #'exwm-input--on-buffer-list-update
                 buffer-list-update-hook)))
      (rename-buffer (concat (and hidden " ") newname)))))

(defun exwm-workspace--x-create-frame (orig-fun params)
  "Set override-redirect on the frame created by `x-create-frame'."
  (let ((frame (funcall orig-fun params)))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ChangeWindowAttributes
                       :window (string-to-number
                                (frame-parameter frame 'outer-window-id))
                       :value-mask xcb:CW:OverrideRedirect
                       :override-redirect 1))
    (xcb:flush exwm--connection)
    frame))

(defsubst exwm-workspace--minibuffer-attached-p ()
  "Return non-nil if the minibuffer is attached.

Please check `exwm-workspace--minibuffer-own-frame-p' first."
  (assq (frame-parameter exwm-workspace--minibuffer 'exwm-container)
        exwm-workspace--id-struts-alist))

;;;###autoload
(defun exwm-workspace-attach-minibuffer ()
  "Attach the minibuffer so that it always shows."
  (interactive)
  (when (and (exwm-workspace--minibuffer-own-frame-p)
             (not (exwm-workspace--minibuffer-attached-p)))
    ;; Reset the frame size.
    (set-frame-height exwm-workspace--minibuffer 1)
    (redisplay)                       ;FIXME.
    (setq exwm-workspace--attached-minibuffer-height
          (frame-pixel-height exwm-workspace--minibuffer))
    (exwm-workspace--show-minibuffer)
    (let ((container (frame-parameter exwm-workspace--minibuffer
                                      'exwm-container)))
      (push (cons container
                  (if (eq exwm-workspace-minibuffer-position 'top)
                      (vector 0 0 exwm-workspace--attached-minibuffer-height 0)
                    (vector 0 0 0 exwm-workspace--attached-minibuffer-height)))
            exwm-workspace--id-struts-alist)
      (exwm-workspace--update-struts)
      (exwm-workspace--update-workareas)
      (dolist (f exwm-workspace--list)
        (exwm-workspace--set-fullscreen f)))))

;;;###autoload
(defun exwm-workspace-detach-minibuffer ()
  "Detach the minibuffer so that it automatically hides."
  (interactive)
  (when (and (exwm-workspace--minibuffer-own-frame-p)
             (exwm-workspace--minibuffer-attached-p))
    (setq exwm-workspace--attached-minibuffer-height 0)
    (let ((container (frame-parameter exwm-workspace--minibuffer
                                      'exwm-container)))
      (setq exwm-workspace--id-struts-alist
            (assq-delete-all container exwm-workspace--id-struts-alist))
      (exwm-workspace--update-struts)
      (exwm-workspace--update-workareas)
      (dolist (f exwm-workspace--list)
        (exwm-workspace--set-fullscreen f))
      (exwm-workspace--hide-minibuffer))))

;;;###autoload
(defun exwm-workspace-toggle-minibuffer ()
  "Attach the minibuffer if it's detached, or detach it if it's attached."
  (interactive)
  (when (exwm-workspace--minibuffer-own-frame-p)
    (if (exwm-workspace--minibuffer-attached-p)
        (exwm-workspace-detach-minibuffer)
      (exwm-workspace-attach-minibuffer))))

(defun exwm-workspace--update-minibuffer-height (&optional echo-area)
  "Update the minibuffer frame height."
  (unless (exwm-workspace--client-p)
    (let ((height
           (with-current-buffer
               (window-buffer (minibuffer-window exwm-workspace--minibuffer))
             (max 1
                  (if echo-area
                      (let ((width (frame-width exwm-workspace--minibuffer))
                            (result 0))
                        (mapc (lambda (i)
                                (setq result
                                      (+ result
                                         (ceiling (1+ (length i)) width))))
                              (split-string (or (current-message) "") "\n"))
                        result)
                    (count-screen-lines))))))
      (when (and (integerp max-mini-window-height)
                 (> height max-mini-window-height))
        (setq height max-mini-window-height))
      (set-frame-height exwm-workspace--minibuffer height))))

(defun exwm-workspace--on-ConfigureNotify (data _synthetic)
  "Adjust the container to fit the minibuffer frame."
  (let ((obj (make-instance 'xcb:ConfigureNotify))
        workarea y)
    (xcb:unmarshal obj data)
    (with-slots (window height) obj
      (when (eq (frame-parameter exwm-workspace--minibuffer 'exwm-outer-id)
                window)
        (when (and (floatp max-mini-window-height)
                   (> height (* max-mini-window-height
                                (exwm-workspace--current-height))))
          (setq height (floor
                        (* max-mini-window-height
                           (exwm-workspace--current-height))))
          (xcb:+request exwm--connection
              (make-instance 'xcb:ConfigureWindow
                             :window window
                             :value-mask xcb:ConfigWindow:Height
                             :height height)))
        (when (/= (exwm-workspace--count) (length exwm-workspace--workareas))
          ;; There is a chance the workareas are not updated timely.
          (exwm-workspace--update-workareas))
        (setq workarea (elt exwm-workspace--workareas
                            exwm-workspace-current-index)
              y (if (eq exwm-workspace-minibuffer-position 'top)
                    (- (aref workarea 1)
                       exwm-workspace--attached-minibuffer-height)
                  (+ (aref workarea 1) (aref workarea 3) (- height)
                     exwm-workspace--attached-minibuffer-height)))
        (xcb:+request exwm--connection
            (make-instance 'xcb:ConfigureWindow
                           :window (frame-parameter exwm-workspace--minibuffer
                                                    'exwm-container)
                           :value-mask (logior xcb:ConfigWindow:Y
                                               xcb:ConfigWindow:Height)
                           :y y
                           :height height))
        (xcb:flush exwm--connection)))))

(defun exwm-workspace--display-buffer (buffer alist)
  "Display BUFFER as if the current workspace is selected."
  ;; Only when the floating minibuffer frame is selected.
  ;; This also protect this functions from being recursively called.
  (when (eq (selected-frame) exwm-workspace--minibuffer)
    (with-selected-frame exwm-workspace--current
      (display-buffer buffer alist))))

(defun exwm-workspace--show-minibuffer ()
  "Show the minibuffer frame."
  ;; Cancel pending timer.
  (when exwm-workspace--display-echo-area-timer
    (cancel-timer exwm-workspace--display-echo-area-timer)
    (setq exwm-workspace--display-echo-area-timer nil))
  ;; Show the minibuffer frame.
  (unless (exwm-workspace--minibuffer-attached-p)
    (exwm--set-geometry (frame-parameter exwm-workspace--minibuffer
                                         'exwm-container)
                        nil nil
                        (frame-pixel-width exwm-workspace--minibuffer)
                        (frame-pixel-height exwm-workspace--minibuffer)))
  (xcb:+request exwm--connection
      (make-instance 'xcb:ConfigureWindow
                     :window (frame-parameter exwm-workspace--minibuffer
                                              'exwm-container)
                     :value-mask xcb:ConfigWindow:StackMode
                     :stack-mode xcb:StackMode:Above))
  (xcb:flush exwm--connection))

(defun exwm-workspace--hide-minibuffer ()
  "Hide the minibuffer frame."
  ;; Hide the minibuffer frame.
  (if (exwm-workspace--minibuffer-attached-p)
      (xcb:+request exwm--connection
          (make-instance 'xcb:ConfigureWindow
                         :window (frame-parameter exwm-workspace--minibuffer
                                                  'exwm-container)
                         :value-mask (logior (if exwm-manage--desktop
                                                 xcb:ConfigWindow:Sibling
                                               0)
                                             xcb:ConfigWindow:StackMode)
                         :sibling exwm-manage--desktop
                         :stack-mode (if exwm-manage--desktop
                                         xcb:StackMode:Above
                                       xcb:StackMode:Below)))
    (exwm--set-geometry (frame-parameter exwm-workspace--minibuffer
                                         'exwm-container)
                        nil nil 1 1))
  (xcb:flush exwm--connection))

(defun exwm-workspace--on-minibuffer-setup ()
  "Run in minibuffer-setup-hook to show the minibuffer and its container."
  (when (and (= 1 (minibuffer-depth))
             (not (exwm-workspace--client-p)))
    (add-hook 'post-command-hook #'exwm-workspace--update-minibuffer-height)
    (exwm-workspace--show-minibuffer))
  ;; FIXME: This is a temporary fix for the *Completions* buffer not
  ;;        being correctly fitted by its displaying window.  As with
  ;;        `exwm-workspace--display-buffer', the problem is caused by
  ;;        the fact that the minibuffer (rather than the workspace)
  ;;        frame is the 'selected frame'.  `get-buffer-window' will
  ;;        fail to retrieve the correct window.  It's likely there are
  ;;        other related issues.
  ;; This is not required by Emacs 24.
  (when (fboundp 'window-preserve-size)
    (let ((window (get-buffer-window "*Completions*"
                                     exwm-workspace--current)))
      (when window
        (fit-window-to-buffer window)
        (window-preserve-size window)))))

(defun exwm-workspace--on-minibuffer-exit ()
  "Run in minibuffer-exit-hook to hide the minibuffer container."
  (when (and (= 1 (minibuffer-depth))
             (not (exwm-workspace--client-p)))
    (remove-hook 'post-command-hook #'exwm-workspace--update-minibuffer-height)
    (exwm-workspace--hide-minibuffer)))

(defun exwm-workspace--on-echo-area-dirty ()
  "Run when new message arrives to show the echo area and its container."
  (when (and (not (active-minibuffer-window))
             (not (exwm-workspace--client-p))
             (or (current-message)
                 cursor-in-echo-area))
    (exwm-workspace--update-minibuffer-height t)
    (exwm-workspace--show-minibuffer)
    (unless (or (not exwm-workspace-display-echo-area-timeout)
                exwm-input--during-command ;e.g. read-event
                input-method-use-echo-area)
      (setq exwm-workspace--display-echo-area-timer
            (run-with-timer exwm-workspace-display-echo-area-timeout nil
                            #'exwm-workspace--echo-area-maybe-clear)))))

(defun exwm-workspace--echo-area-maybe-clear ()
  "Eventually clear the echo area container."
  (exwm--log)
  (if (not (current-message))
      (exwm-workspace--on-echo-area-clear)
    ;; Reschedule.
    (cancel-timer exwm-workspace--display-echo-area-timer)
    (setq exwm-workspace--display-echo-area-timer
          (run-with-timer exwm-workspace-display-echo-area-timeout nil
                          #'exwm-workspace--echo-area-maybe-clear))))

(defun exwm-workspace--on-echo-area-clear ()
  "Run in echo-area-clear-hook to hide echo area container."
  (unless (exwm-workspace--client-p)
    (unless (active-minibuffer-window)
      (exwm-workspace--hide-minibuffer))
    (when exwm-workspace--display-echo-area-timer
      (cancel-timer exwm-workspace--display-echo-area-timer)
      (setq exwm-workspace--display-echo-area-timer nil))))

(defun exwm-workspace--set-desktop-geometry ()
  "Set _NET_DESKTOP_GEOMETRY."
  ;; We don't support large desktop so it's the same with screen size.
  (xcb:+request exwm--connection
      (make-instance 'xcb:ewmh:set-_NET_DESKTOP_GEOMETRY
                     :window exwm--root
                     :width (x-display-pixel-width)
                     :height (x-display-pixel-height))))

(defun exwm-workspace--add-frame-as-workspace (frame)
  "Configure frame FRAME to be treated as a workspace."
  (setq exwm-workspace--list (nconc exwm-workspace--list (list frame)))
  (let ((outer-id (string-to-number (frame-parameter frame
                                                     'outer-window-id)))
        (window-id (string-to-number (frame-parameter frame 'window-id)))
        (container (xcb:generate-id exwm--connection)))
    ;; Save window IDs
    (set-frame-parameter frame 'exwm-outer-id outer-id)
    (set-frame-parameter frame 'exwm-id window-id)
    (set-frame-parameter frame 'exwm-container container)
    ;; In case it's created by emacsclient.
    (set-frame-parameter frame 'client nil)
    ;; Copy RandR frame parameters from the first workspace to
    ;; prevent potential problems.  The values do not matter here as
    ;; they'll be updated by the RandR module later.
    (let ((w (car exwm-workspace--list)))
      (dolist (param '(exwm-randr-output
                       exwm-geometry))
        (set-frame-parameter frame param (frame-parameter w param))))
    (xcb:+request exwm--connection
        (make-instance 'xcb:CreateWindow
                       :depth 0
                       :wid container
                       :parent exwm--root
                       :x -1
                       :y -1
                       :width 1
                       :height 1
                       :border-width 0
                       :class xcb:WindowClass:InputOutput
                       :visual 0
                       :value-mask (logior xcb:CW:BackPixmap
                                           xcb:CW:OverrideRedirect)
                       :background-pixmap xcb:BackPixmap:ParentRelative
                       :override-redirect 1))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ConfigureWindow
                       :window container
                       :value-mask xcb:ConfigWindow:StackMode
                       :stack-mode xcb:StackMode:Below))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ewmh:set-_NET_WM_NAME
                       :window container
                       :data
                       (format "EXWM workspace %d frame container"
                               (exwm-workspace--position frame))))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ReparentWindow
                       :window outer-id :parent container :x 0 :y 0))
    (xcb:+request exwm--connection
        (make-instance 'xcb:MapWindow :window container)))
  (xcb:flush exwm--connection)
  ;; Delay making the workspace fullscreen until Emacs becomes idle
  (exwm--defer 0 #'set-frame-parameter frame 'fullscreen 'fullboth)
  ;; Update EWMH properties.
  (exwm-workspace--update-ewmh-props)
  (if exwm-workspace--create-silently
      (setq exwm-workspace--switch-history-outdated t)
    (exwm-workspace-switch frame t)
    (run-hooks 'exwm-workspace-list-change-hook)))

(defun exwm-workspace--remove-frame-as-workspace (frame)
  "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)
  (let* ((index (exwm-workspace--position frame))
         (lastp (= index (1- (exwm-workspace--count))))
         (nextw (elt exwm-workspace--list (+ index (if lastp -1 +1)))))
    ;; Need to remove the workspace from the list in order for
    ;; the correct calculation of indexes.
    (setq exwm-workspace--list (delete frame exwm-workspace--list))
    ;; Clients need to be moved to some other workspace before this is being
    ;; removed.
    (dolist (pair exwm--id-buffer-alist)
      (with-current-buffer (cdr pair)
        (when (eq exwm--frame frame)
          (exwm-workspace-move-window nextw exwm--id))))
    ;; Update the _NET_WM_DESKTOP property of each X window affected.
    (dolist (pair exwm--id-buffer-alist)
      (when (<= (1- index)
                (exwm-workspace--position (buffer-local-value 'exwm--frame
                                                              (cdr pair))))
        (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 nextw)))
  ;; Reparent out the frame.
  (let ((outer-id (frame-parameter frame 'exwm-outer-id)))
    (xcb:+request exwm--connection
        (make-instance 'xcb:UnmapWindow
                       :window outer-id))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ReparentWindow
                       :window outer-id
                       :parent exwm--root
                       :x 0
                       :y 0))
    ;; Reset the override-redirect.
    (xcb:+request exwm--connection
        (make-instance 'xcb:ChangeWindowAttributes
                       :window outer-id
                       :value-mask xcb:CW:OverrideRedirect
                       :override-redirect 0))
    ;; Remove fullscreen state.
    (xcb:+request exwm--connection
        (make-instance 'xcb:ewmh:set-_NET_WM_STATE
                       :window outer-id
                       :data nil))
    (xcb:+request exwm--connection
        (make-instance 'xcb:MapWindow
                       :window outer-id)))
  ;; Destroy the container.
  (xcb:+request exwm--connection
      (make-instance 'xcb:DestroyWindow
                     :window (frame-parameter frame 'exwm-container)))
  (xcb:flush exwm--connection)
  ;; Update EWMH properties.
  (exwm-workspace--update-ewmh-props)
  ;; Update switch history.
  (setq exwm-workspace--switch-history-outdated t)
  (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."
  (cond
   ((not (exwm-workspace--workspace-p frame))
    (exwm--log "Frame `%s' is not a workspace" frame))
   (t
    (when (= 1 (exwm-workspace--count))
      ;; The user managed to delete the last workspace, so create a new one.
      (exwm--log "Last workspace deleted; create a new one")
      ;; TODO: this makes sense in the hook.  But we need a function that takes
      ;; care of converting a workspace into a regular unmanaged frame.
      (let ((exwm-workspace--create-silently t))
        (make-frame)))
    (exwm-workspace--remove-frame-as-workspace frame))))

(defun exwm-workspace--on-after-make-frame (frame)
  "Hook run upon `make-frame' that configures FRAME as a workspace."
  (cond
   ((exwm-workspace--workspace-p frame)
    (exwm--log "Frame `%s' is already a workspace" frame))
   ((not (display-graphic-p frame))
    (exwm--log "Frame `%s' is not graphical" frame))
   ((not (string-equal
          (replace-regexp-in-string "\\.0$" ""
                                    (slot-value exwm--connection 'display))
          (replace-regexp-in-string "\\.0$" ""
                                    (frame-parameter frame 'display))))
    (exwm--log "Frame `%s' is on a different DISPLAY (%S instead of %S)"
               frame
               (frame-parameter frame 'display)
               (slot-value exwm--connection 'display)))
   ((frame-parameter frame 'unsplittable)
    ;; We create floating frames with the "unsplittable" parameter set.
    ;; Though it may not be a floating frame, we won't treat an
    ;; unsplittable frame as a workspace anyway.
    (exwm--log "Frame `%s' is floating" frame))
   (t
    (exwm--log "Adding frame `%s' as workspace" frame)
    (exwm-workspace--add-frame-as-workspace frame))))

(defun exwm-workspace--update-ewmh-props ()
  "Update EWMH properties to match the workspace list."
  (let ((num-workspaces (exwm-workspace--count)))
    ;; Avoid setting 0 desktops.
    (when (= 0 num-workspaces)
      (setq num-workspaces 1))
    ;; Set _NET_NUMBER_OF_DESKTOPS.
    (xcb:+request exwm--connection
        (make-instance 'xcb:ewmh:set-_NET_NUMBER_OF_DESKTOPS
                       :window exwm--root :data num-workspaces))
    ;; Set _NET_DESKTOP_GEOMETRY.
    (exwm-workspace--set-desktop-geometry)
    ;; Update workareas.
    (exwm-workspace--update-workareas))
  (xcb:flush exwm--connection))

(defun exwm-workspace--modify-all-x-frames-parameters (new-x-parameters)
  "Modifies `window-system-default-frame-alist' for the X Window System.
NEW-X-PARAMETERS is an alist of frame parameters, merged into current
`window-system-default-frame-alist' for the X Window System.  The parameters are
applied to all subsequently created X frames."
  ;; The parameters are modified in place; take current
  ;; ones or insert a new X-specific list.
  (let ((x-parameters (or (assq 'x window-system-default-frame-alist)
                          (let ((new-x-parameters '(x)))
                            (push new-x-parameters
                                  window-system-default-frame-alist)
                            new-x-parameters))))
    (setf (cdr x-parameters)
          (append new-x-parameters (cdr x-parameters)))))

(defun exwm-workspace--handle-focus-in (_orig-func _event)
  "Replacement for `handle-focus-in'."
  (interactive "e"))

(defun exwm-workspace--handle-focus-out (_orig-func _event)
  "Replacement for `handle-focus-out'."
  (interactive "e"))

(defun exwm-workspace--init-minibuffer-frame ()
  ;; Initialize workspaces without minibuffers.
  (setq exwm-workspace--minibuffer
        (make-frame '((window-system . x) (minibuffer . only)
                      (left . 10000) (right . 10000)
                      (width . 1) (height . 1)
                      (client . nil))))
  ;; This is the only usable minibuffer frame.
  (setq default-minibuffer-frame exwm-workspace--minibuffer)
  (exwm-workspace--modify-all-x-frames-parameters
   '((minibuffer . nil)))
  (let ((outer-id (string-to-number
                   (frame-parameter exwm-workspace--minibuffer
                                    'outer-window-id)))
        (window-id (string-to-number
                    (frame-parameter exwm-workspace--minibuffer
                                     'window-id)))
        (container (xcb:generate-id exwm--connection)))
    (set-frame-parameter exwm-workspace--minibuffer
                         'exwm-outer-id outer-id)
    (set-frame-parameter exwm-workspace--minibuffer 'exwm-id window-id)
    (set-frame-parameter exwm-workspace--minibuffer 'exwm-container
                         container)
    (xcb:+request exwm--connection
        (make-instance 'xcb:CreateWindow
                       :depth 0
                       :wid container
                       :parent exwm--root
                       :x 0
                       :y 0
                       :width 1
                       :height 1
                       :border-width 0
                       :class xcb:WindowClass:InputOutput
                       :visual 0
                       :value-mask (logior xcb:CW:BackPixmap
                                           xcb:CW:OverrideRedirect)
                       :background-pixmap xcb:BackPixmap:ParentRelative
                       :override-redirect 1))
    (xcb:+request exwm--connection
        (make-instance 'xcb:ewmh:set-_NET_WM_NAME
                       :window container
                       :data "EXWM minibuffer container"))
    ;; Reparent the minibuffer frame to the container.
    (xcb:+request exwm--connection
        (make-instance 'xcb:ReparentWindow
                       :window outer-id :parent container :x 0 :y 0))
    ;; Map the container.
    (xcb:+request exwm--connection
        (make-instance 'xcb:MapWindow
                       :window container))
    ;; Attach event listener for monitoring the frame
    (xcb:+request exwm--connection
        (make-instance 'xcb:ChangeWindowAttributes
                       :window outer-id
                       :value-mask xcb:CW:EventMask
                       :event-mask xcb:EventMask:StructureNotify))
    (xcb:+event exwm--connection 'xcb:ConfigureNotify
                #'exwm-workspace--on-ConfigureNotify))
  ;; Show/hide minibuffer / echo area when they're active/inactive.
  (add-hook 'minibuffer-setup-hook #'exwm-workspace--on-minibuffer-setup)
  (add-hook 'minibuffer-exit-hook #'exwm-workspace--on-minibuffer-exit)
  (setq exwm-workspace--timer
        (run-with-idle-timer 0 t #'exwm-workspace--on-echo-area-dirty))
  (add-hook 'echo-area-clear-hook #'exwm-workspace--on-echo-area-clear)
  ;; The default behavior of `display-buffer' (indirectly called by
  ;; `minibuffer-completion-help') is not correct here.
  (cl-pushnew '(exwm-workspace--display-buffer) display-buffer-alist
              :test #'equal))

(defun exwm-workspace--exit-minibuffer-frame ()
  ;; Only on minibuffer-frame.
  (remove-hook 'minibuffer-setup-hook #'exwm-workspace--on-minibuffer-setup)
  (remove-hook 'minibuffer-exit-hook #'exwm-workspace--on-minibuffer-exit)
  (remove-hook 'echo-area-clear-hook #'exwm-workspace--on-echo-area-clear)
  (when exwm-workspace--timer
    (cancel-timer exwm-workspace--timer)
    (setq exwm-workspace--timer nil))
  (setq display-buffer-alist
        (cl-delete '(exwm-workspace--display-buffer) display-buffer-alist
                   :test #'equal))
  (setq default-minibuffer-frame nil)
  (let ((id (frame-parameter exwm-workspace--minibuffer 'exwm-outer-id)))
    (when (and exwm-workspace--minibuffer id)
      (xcb:+request exwm--connection
          (make-instance 'xcb:ReparentWindow
                         :window id
                         :parent exwm--root
                         :x 0
                         :y 0)))
    (setq exwm-workspace--minibuffer nil)))

(defun exwm-workspace--init ()
  "Initialize workspace module."
  ;; Prevent unexpected exit
  (setq exwm-workspace--fullscreen-frame-count 0)
  (exwm-workspace--modify-all-x-frames-parameters
   '((internal-border-width . 0)))
  (let ((initial-workspaces (frame-list)))
    (if (not (exwm-workspace--minibuffer-own-frame-p))
        ;; Initialize workspaces with minibuffers.
        (when (< 1 (length initial-workspaces))
          ;; Exclude the initial frame.
          (dolist (i initial-workspaces)
            (unless (frame-parameter i 'window-id)
              (setq initial-workspaces (delq i initial-workspaces))))
          (setq exwm-workspace--client
                (frame-parameter (car initial-workspaces) 'client))
          (let ((f (car initial-workspaces)))
            ;; Remove the possible internal border.
            (set-frame-parameter f 'internal-border-width 0)
            ;; Prevent user from deleting the first frame by accident.
            (set-frame-parameter f 'client nil)))
      (exwm-workspace--init-minibuffer-frame)
      ;; Remove/hide existing frames.
      (dolist (f initial-workspaces)
        (if (frame-parameter f 'client)
            (progn
              (unless exwm-workspace--client
                (setq exwm-workspace--client (frame-parameter f 'client)))
              (make-frame-invisible f))
          (when (eq 'x (framep f))   ;do not delete the initial frame.
            (delete-frame f))))
      ;; Recreate one frame with the external minibuffer set.
      (setq initial-workspaces (list (make-frame '((window-system . x)
                                                   (client . nil))))))
    ;; Prevent `other-buffer' from selecting already displayed EXWM buffers.
    (modify-all-frames-parameters
     '((buffer-predicate . exwm-layout--other-buffer-predicate)))
    ;; Create remaining workspaces.
    (dotimes (_ (- exwm-workspace-number (length initial-workspaces)))
      (nconc initial-workspaces (list (make-frame '((window-system . x)
                                                    (client . nil))))))
    ;; Configure workspaces
    (dolist (i initial-workspaces)
      (exwm-workspace--add-frame-as-workspace i)))
  (xcb:flush exwm--connection)
  ;; We have to advice `x-create-frame' or every call to it would hang EXWM
  (advice-add 'x-create-frame :around #'exwm-workspace--x-create-frame)
  ;; We have to manually handle focus-in and focus-out events for Emacs
  ;; frames.
  (advice-add 'handle-focus-in :around #'exwm-workspace--handle-focus-in)
  (advice-add 'handle-focus-out :around #'exwm-workspace--handle-focus-out)
  ;; Make new frames create new workspaces.
  (add-hook 'after-make-frame-functions
            #'exwm-workspace--on-after-make-frame)
  (add-hook 'delete-frame-functions #'exwm-workspace--on-delete-frame)
  (when (exwm-workspace--minibuffer-own-frame-p)
    (add-hook 'exwm-input--event-hook
              #'exwm-workspace--on-echo-area-clear))
  ;; Switch to the first workspace
  (exwm-workspace-switch 0 t)
  ;; Prevent frame parameters introduced by this module from being
  ;; saved/restored.
  (dolist (i '(exwm-active exwm-outer-id exwm-id exwm-container exwm-geometry
                           exwm-selected-window exwm-urgency fullscreen))
    (unless (assq i frameset-filter-alist)
      (push (cons i :never) frameset-filter-alist))))

(defun exwm-workspace--exit ()
  "Exit the workspace module."
  (when (exwm-workspace--minibuffer-own-frame-p)
    (exwm-workspace--exit-minibuffer-frame))
  (advice-remove 'x-create-frame #'exwm-workspace--x-create-frame)
  (advice-remove 'handle-focus-in #'exwm-workspace--handle-focus-in)
  (advice-remove 'handle-focus-out #'exwm-workspace--handle-focus-out)
  (remove-hook 'after-make-frame-functions
               #'exwm-workspace--on-after-make-frame)
  (remove-hook 'delete-frame-functions
               #'exwm-workspace--on-delete-frame)
  (when (exwm-workspace--minibuffer-own-frame-p)
    (remove-hook 'exwm-input--event-hook
                 #'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)
  (dolist (i exwm-workspace--list)
    (exwm-workspace--remove-frame-as-workspace i)
    (modify-frame-parameters i '((exwm-selected-window . nil)
                                 (exwm-urgency . nil)
                                 (exwm-outer-id . nil)
                                 (exwm-id . nil)
                                 (exwm-container . nil)
                                 ;; (internal-border-width . nil) ; integerp
                                 ;; (client . nil)
                                 (fullscreen . nil)
                                 (buffer-predicate . nil))))
  ;; Restore the 'client' frame parameter (before `exwm-exit').
  (when exwm-workspace--client
    (dolist (f exwm-workspace--list)
      (set-frame-parameter f 'client exwm-workspace--client))
    (when (exwm-workspace--minibuffer-own-frame-p)
      (set-frame-parameter exwm-workspace--minibuffer 'client
                           exwm-workspace--client))
    (setq exwm-workspace--client nil)))

(defun exwm-workspace--post-init ()
  "The second stage in the initialization of the workspace module."
  (when exwm-workspace--client
    ;; Reset the 'fullscreen' frame parameter to make emacsclinet frames
    ;; fullscreen (even without the RandR module enabled).
    (dolist (i exwm-workspace--list)
      (set-frame-parameter i 'fullscreen nil)
      (set-frame-parameter i 'fullscreen 'fullboth)))
  ;; Wait until all workspace frames are resized.
  (with-timeout (1)
    (while (< exwm-workspace--fullscreen-frame-count (exwm-workspace--count))
      (accept-process-output nil 0.1)))
  (setq exwm-workspace--fullscreen-frame-count nil))



(provide 'exwm-workspace)

;;; exwm-workspace.el ends here