Add system tray support

* exwm-systemtray.el: New module adds a simple system tray (using the X11
System Tray protocol).

* exwm-workspace.el (exwm-workspace-switch-hook, exwm-workspace-switch):
New hook run after switching workspace.

1 files changed, 372 insertions, 0 deletions

diff --git a/exwm-systemtray.el b/exwm-systemtray.el
new file mode 100644
index 000000000000..c892fcc1a76a
--- /dev/null
+++ b/exwm-systemtray.el
@@ -0,0 +1,372 @@
+;;; exwm-systemtray.el --- System Tray Module for  -*- lexical-binding: t -*-
+;;;                        EXWM
+
+;; Copyright (C) 2016 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 system tray support for EXWM.
+
+;; To use this module, load and enable it as follows:
+;;   (require 'exwm-systemtray)
+;;   (exwm-systemtray-enable)
+
+;;; Code:
+
+(require 'xcb-xembed)
+(require 'xcb-systemtray)
+(require 'exwm-core)
+(require 'exwm-workspace)
+
+(defclass exwm-systemtray--icon ()
+  ((width :initarg :width)
+   (height :initarg :height)
+   (visible :initarg :visible))
+  :documentation "Attributes of a system tray icon.")
+
+;; GTK icons require at least 16 pixels to show normally.
+(defconst exwm-systemtray--icon-min-size 16 "Minimum icon size.")
+
+(defvar exwm-systemtray-height (max exwm-systemtray--icon-min-size
+                                    (line-pixel-height))
+  "System tray height.
+
+You shall use the default value if using auto-hide minibuffer.")
+
+(defvar exwm-systemtray-icon-gap 2 "Gap between icons.")
+
+(defvar exwm-systemtray--connection nil "The X connection.")
+(defvar exwm-systemtray--list nil "The icon list.")
+(defvar exwm-systemtray--selection-owner-window nil
+  "The selection owner window.")
+(defvar exwm-systemtray--embedder nil "The embedder window.")
+
+(defun exwm-systemtray--embed (icon)
+  "Embed an icon."
+  (exwm--log "(System Tray) Try to embed #x%x" icon)
+  (let ((info (xcb:+request-unchecked+reply exwm-systemtray--connection
+                  (make-instance 'xcb:xembed:get-_XEMBED_INFO
+                                 :window icon)))
+        width* height* visible)
+    (when info
+      (exwm--log "(System Tray) Embed #x%x" icon)
+      (with-slots (width height)
+          (xcb:+request-unchecked+reply exwm-systemtray--connection
+              (make-instance 'xcb:GetGeometry :drawable icon))
+        (setq height* exwm-systemtray-height
+              width* (round (* width (/ (float height*) height))))
+        (when (< width* exwm-systemtray--icon-min-size)
+          (setq width* exwm-systemtray--icon-min-size
+                height* (round (* height (/ (float width*) width)))))
+        (exwm--log "(System Tray) Resize from %dx%d to %dx%d"
+                   width height width* height*))
+      ;; Reparent to the embedder.
+      (xcb:+request exwm-systemtray--connection
+          (make-instance 'xcb:ReparentWindow
+                         :window icon
+                         :parent exwm-systemtray--embedder
+                         :x 0
+                         ;; Vertically centered.
+                         :y (/ (- exwm-systemtray-height height*) 2)))
+      ;; Resize the icon.
+      (xcb:+request exwm-systemtray--connection
+          (make-instance 'xcb:ConfigureWindow
+                         :window icon
+                         :value-mask (logior xcb:ConfigWindow:Width
+                                             xcb:ConfigWindow:Height
+                                             xcb:ConfigWindow:BorderWidth)
+                         :width width*
+                         :height height*
+                         :border-width 0))
+      ;; Set event mask.
+      (xcb:+request exwm-systemtray--connection
+          (make-instance 'xcb:ChangeWindowAttributes
+                         :window icon
+                         :value-mask xcb:CW:EventMask
+                         :event-mask (logior xcb:EventMask:ResizeRedirect
+                                             xcb:EventMask:PropertyChange)))
+      (when (setq visible
+                  (/= 0 (logand (slot-value info 'flags) xcb:xembed:MAPPED)))
+        (exwm--log "(System Tray) Map the window")
+        (xcb:+request exwm-systemtray--connection
+            (make-instance 'xcb:MapWindow :window icon)))
+      (xcb:+request exwm-systemtray--connection
+          (make-instance 'xcb:xembed:SendEvent
+                         :destination icon
+                         :event
+                         (xcb:marshal
+                          (make-instance 'xcb:xembed:EMBEDDED-NOTIFY
+                                         :window icon
+                                         :time xcb:Time:CurrentTime
+                                         :embedder exwm-systemtray--embedder
+                                         :version 0)
+                          exwm-systemtray--connection)))
+      (push `(,icon . ,(make-instance 'exwm-systemtray--icon
+                                      :width width*
+                                      :height height*
+                                      :visible visible))
+            exwm-systemtray--list)
+      (exwm-systemtray--refresh))))
+
+(defun exwm-systemtray--unembed (icon)
+  "Unembed an icon."
+  (exwm--log "(System Tray) Unembed #x%x" icon)
+  (xcb:+request exwm-systemtray--connection
+      (make-instance 'xcb:UnmapWindow :window icon))
+  (xcb:+request exwm-systemtray--connection
+      (make-instance 'xcb:ReparentWindow
+                     :window icon
+                     :parent exwm--root
+                     :x 0 :y 0))
+  (setq exwm-systemtray--list
+        (assq-delete-all icon exwm-systemtray--list))
+  (exwm-systemtray--refresh))
+
+(defun exwm-systemtray--refresh ()
+  "Refresh the system tray."
+  ;; Make sure to redraw the embedder.
+  (xcb:+request exwm-systemtray--connection
+      (make-instance 'xcb:UnmapWindow :window exwm-systemtray--embedder))
+  (let ((x exwm-systemtray-icon-gap)
+        map)
+    (dolist (pair exwm-systemtray--list)
+      (when (slot-value (cdr pair) 'visible)
+        (xcb:+request exwm-systemtray--connection
+            (make-instance 'xcb:ConfigureWindow
+                           :window (car pair)
+                           :value-mask xcb:ConfigWindow:X
+                           :x x))
+        (setq x (+ x (slot-value (cdr pair) 'width)
+                   exwm-systemtray-icon-gap))
+        (setq map t)))
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:ConfigureWindow
+                       :window exwm-systemtray--embedder
+                       :value-mask (logior xcb:ConfigWindow:X
+                                           xcb:ConfigWindow:Width)
+                       :x (- (frame-pixel-width exwm-workspace--current) x)
+                       :width x))
+    (when map
+      (xcb:+request exwm-systemtray--connection
+          (make-instance 'xcb:MapWindow :window exwm-systemtray--embedder))))
+  (xcb:flush exwm-systemtray--connection))
+
+(defun exwm-systemtray--on-DestroyNotify (data _synthetic)
+  "Unembed icons on DestroyNotify."
+  (let ((obj (make-instance 'xcb:DestroyNotify)))
+    (xcb:unmarshal obj data)
+    (with-slots (window) obj
+      (when (alist-get window exwm-systemtray--list)
+        (exwm-systemtray--unembed window)))))
+
+(defun exwm-systemtray--on-ReparentNotify (data _synthetic)
+  "Unembed icons on ReparentNotify."
+  (let ((obj (make-instance 'xcb:ReparentNotify)))
+    (xcb:unmarshal obj data)
+    (with-slots (window parent) obj
+      (when (and (/= parent exwm-systemtray--embedder)
+                 (alist-get window exwm-systemtray--list))
+        (exwm-systemtray--unembed window)))))
+
+(defun exwm-systemtray--on-ResizeRequest (data _synthetic)
+  "Resize the tray icon on ResizeRequest."
+  (let ((obj (make-instance 'xcb:ResizeRequest))
+        attr)
+    (xcb:unmarshal obj data)
+    (with-slots (window width height) obj
+      (when (setq attr (alist-get window exwm-systemtray--list))
+        (with-slots ((width* width)
+                     (height* height))
+            attr
+          (setq height* exwm-systemtray-height
+                width* (round (* width (/ (float height*) height))))
+          (when (< width* exwm-systemtray--icon-min-size)
+            (setq width* exwm-systemtray--icon-min-size
+                  height* (round (* height (/ (float width*) width)))))
+          (xcb:+request exwm-systemtray--connection
+              (make-instance 'xcb:ConfigureWindow
+                             :window window
+                             :value-mask (logior xcb:ConfigWindow:Y
+                                                 xcb:ConfigWindow:Width
+                                                 xcb:ConfigWindow:Height)
+                             ;; Vertically centered.
+                             :y (/ (- exwm-systemtray-height height*) 2)
+                             :width width*
+                             :height height*)))
+        (exwm-systemtray--refresh)))))
+
+(defun exwm-systemtray--on-PropertyNotify (data _synthetic)
+  "Map/Unmap the tray icon on PropertyNotify."
+  (let ((obj (make-instance 'xcb:PropertyNotify))
+        attr info visible)
+    (xcb:unmarshal obj data)
+    (with-slots (window atom state) obj
+      (when (and (eq state xcb:Property:NewValue)
+                 (eq atom xcb:Atom:_XEMBED_INFO)
+                 (setq attr (alist-get window exwm-systemtray--list)))
+        (setq info (xcb:+request-unchecked+reply exwm-systemtray--connection
+                       (make-instance 'xcb:xembed:get-_XEMBED_INFO
+                                      :window window)))
+        (when info
+          (setq visible (/= 0 (logand (slot-value info 'flags)
+                                      xcb:xembed:MAPPED)))
+          (exwm--log "(System Tray) #x%x visible? %s" window visible)
+          (if visible
+              (xcb:+request exwm-systemtray--connection
+                  (make-instance 'xcb:MapWindow :window window))
+            (xcb:+request exwm-systemtray--connection
+                (make-instance 'xcb:UnmapWindow :window window)))
+          (setf (slot-value attr 'visible) visible)
+          (exwm-systemtray--refresh))))))
+
+(defun exwm-systemtray--on-ClientMessage (data _synthetic)
+  "Handle client messages."
+  (let ((obj (make-instance 'xcb:ClientMessage))
+        opcode data32)
+    (xcb:unmarshal obj data)
+    (with-slots (window type data) obj
+      (when (eq type xcb:Atom:_NET_SYSTEM_TRAY_OPCODE)
+        (setq data32 (slot-value data 'data32)
+              opcode (elt data32 1))
+        (cond ((= opcode xcb:systemtray:opcode:REQUEST-DOCK)
+               (exwm-systemtray--embed (elt data32 2)))
+              ((= opcode xcb:systemtray:opcode:BEGIN-MESSAGE)
+               ;; FIXME
+               )
+              ((= opcode xcb:systemtray:opcode:CANCEL-MESSAGE)
+               ;; FIXME
+               )
+              (t
+               (exwm--log "(System Tray) Unknown opcode message: %s" obj)))))))
+
+(defun exwm-systemtray--on-exwm-workspace-switch ()
+  "Reparent the system tray in `exwm-workspace-switch-hook'."
+  (xcb:+request exwm-systemtray--connection
+      (make-instance 'xcb:ReparentWindow
+                     :window exwm-systemtray--embedder
+                     :parent (string-to-number
+                              (frame-parameter exwm-workspace--current
+                                               'window-id))
+                     :x 0
+                     :y (- (frame-pixel-height exwm-workspace--current)
+                           exwm-systemtray-height)))
+  (exwm-systemtray--refresh))
+
+(defvar xcb:Atom:_NET_SYSTEM_TRAY_S0)
+
+(defun exwm-systemtray--init ()
+  "Initialize system tray module."
+  (cl-assert (not exwm-systemtray--connection))
+  (cl-assert (not exwm-systemtray--list))
+  (cl-assert (not exwm-systemtray--selection-owner-window))
+  (cl-assert (not exwm-systemtray--embedder))
+  ;; Create a new connection.
+  (setq exwm-systemtray--connection (xcb:connect-to-socket))
+  (set-process-query-on-exit-flag (slot-value exwm-systemtray--connection
+                                              'process)
+                                  nil)
+  ;; Initialize XELB modules.
+  (xcb:xembed:init exwm-systemtray--connection)
+  (xcb:systemtray:init exwm-systemtray--connection)
+  ;; Acquire the manager selection _NET_SYSTEM_TRAY_S0.
+  (with-slots (owner)
+      (xcb:+request-unchecked+reply exwm-systemtray--connection
+          (make-instance 'xcb:GetSelectionOwner
+                         :selection xcb:Atom:_NET_SYSTEM_TRAY_S0))
+    (when (/= owner xcb:Window:None)
+      (error "[EXWM] Other system tray detected")))
+  (let ((id (xcb:generate-id exwm-systemtray--connection)))
+    (setq exwm-systemtray--selection-owner-window id)
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:CreateWindow
+                       :depth 0 :wid id :parent exwm--root
+                       :x 0 :y 0 :width 1 :height 1
+                       :border-width 0 :class xcb:WindowClass:InputOnly
+                       :visual 0 :value-mask xcb:CW:OverrideRedirect
+                       :override-redirect 1))
+    ;; Get the selection ownership.
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:SetSelectionOwner
+                       :owner id
+                       :selection xcb:Atom:_NET_SYSTEM_TRAY_S0
+                       :time xcb:Time:CurrentTime))
+    ;; Set _NET_WM_NAME.
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:ewmh:set-_NET_WM_NAME
+                       :window id :data "EXWM system tray selection owner"))
+    ;; Set the _NET_SYSTEM_TRAY_ORIENTATION property.
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:xembed:set-_NET_SYSTEM_TRAY_ORIENTATION
+                       :window id
+                       :data xcb:systemtray:ORIENTATION:HORZ)))
+  ;; Create the embedder.
+  (let ((id (xcb:generate-id exwm-systemtray--connection))
+        parent y)
+    (setq exwm-systemtray--embedder id)
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:CreateWindow
+                       :depth 0 :wid id :parent exwm--root
+                       :x 0 :y 0 :width 1 :height exwm-systemtray-height
+                       :border-width 0 :class xcb:WindowClass:CopyFromParent
+                       :visual 0 :value-mask xcb:CW:EventMask
+                       :event-mask xcb:EventMask:SubstructureNotify))
+    (if exwm-workspace-minibuffer-position
+        (setq parent (frame-parameter exwm-workspace--minibuffer
+                                      'exwm-container)
+              ;; Vertically centered.
+              y (/ (- (line-pixel-height) exwm-systemtray-height) 2))
+      (setq parent (string-to-number (frame-parameter exwm-workspace--current
+                                                      'window-id))
+            ;; Bottom aligned.
+            y (- (frame-pixel-height exwm-workspace--current)
+                 exwm-systemtray-height)))
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:ReparentWindow
+                       :window id :parent parent :x 0 :y y))
+    ;; Set _NET_WM_NAME.
+    (xcb:+request exwm-systemtray--connection
+        (make-instance 'xcb:ewmh:set-_NET_WM_NAME
+                       :window id :data "EXWM system tray embedder")))
+  (xcb:flush exwm-systemtray--connection)
+  ;; Attach event listeners.
+  (xcb:+event exwm-systemtray--connection 'xcb:DestroyNotify
+              #'exwm-systemtray--on-DestroyNotify)
+  (xcb:+event exwm-systemtray--connection 'xcb:ReparentNotify
+              #'exwm-systemtray--on-ReparentNotify)
+  (xcb:+event exwm-systemtray--connection 'xcb:ResizeRequest
+              #'exwm-systemtray--on-ResizeRequest)
+  (xcb:+event exwm-systemtray--connection 'xcb:PropertyNotify
+              #'exwm-systemtray--on-PropertyNotify)
+  (xcb:+event exwm-systemtray--connection 'xcb:ClientMessage
+              #'exwm-systemtray--on-ClientMessage)
+  ;; Add hook to reparent the embedder.
+  (unless exwm-workspace-minibuffer-position
+    (add-hook 'exwm-workspace-switch-hook
+              #'exwm-systemtray--on-exwm-workspace-switch)))
+
+(defun exwm-systemtray-enable ()
+  "Enable system tray support for EXWM."
+  (add-hook 'exwm-init-hook #'exwm-systemtray--init))
+
+
+
+(provide 'exwm-systemtray)
+
+;; exwm-systemtray.el ends here