services: Add Plasma desktop service.

* gnu/services/desktop.scm (kde-desktop-service-type): New variable.
(<kde-desktop-configuration>): New record type.
(kde-desktop-configuration): New procedure.
* doc/guix.texi (Desktop Services): Document it.

Co-authored-by: Zheng Junjie <873216071@qq.com>
Signed-off-by: 宋文武 <iyzsong@member.fsf.org>

doc/guix.texi

@@ -116,6 +116,7 @@ Copyright @copyright{} 2022 Antero Mejr@*
 Copyright @copyright{} 2023 Karl Hallsby@*
 Copyright @copyright{} 2023 Nathaniel Nicandro@*
 Copyright @copyright{} 2023 Tanguy Le Carrour@*
+Copyright @copyright{} 2023 Zheng Junjie@*
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -23721,6 +23722,23 @@ The GNOME package to use.
 @end table
 @end deftp
 
+@defvar plasma-desktop-service-type
+This is the type of the service that adds the @uref{https://kde.org/plasma-desktop/,
+Plasma} desktop environment.  Its value is a @code{plasma-desktop-configuration}
+object (see below).
+
+This service adds the @code{plasma} package to the system profile.
+@end defvar
+
+@deftp {Data Type} plasma-desktop-configuration
+Configuration record for the Plasma desktop environment.
+
+@table @asis
+@item @code{plasma} (default: @code{plasma})
+The Plasma package to use.
+@end table
+@end deftp
+
 @defvar xfce-desktop-service-type
 This is the type of a service to run the @uref{Xfce, https://xfce.org/}
 desktop environment.  Its value is an @code{xfce-desktop-configuration} object

gnu/services/desktop.scm

@@ -5,6 +5,7 @@
 ;;; Copyright © 2016 Sou Bunnbu <iyzsong@gmail.com>
 ;;; Copyright © 2017, 2020, 2022, 2023 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;; Copyright © 2017 Nikita <nikita@n0.is>
+;;; Copyright © 2017, 2019 Hartmut Goebel <h.goebel@crazy-compilers.com>
 ;;; Copyright © 2018, 2020, 2022 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2018, 2023 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2017, 2019 Christopher Baines <mail@cbaines.net>
@@ -15,6 +16,7 @@
 ;;; Copyright © 2021 Brice Waegeneire <brice@waegenei.re>
 ;;; Copyright © 2021, 2022 muradm <mail@muradm.net>
 ;;; Copyright © 2023 Bruno Victal <mirai@makinata.eu>
+;;; Copyright © 2023 Zheng Junjie <873216071@qq.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -55,6 +57,9 @@
   #:use-module (gnu packages cups)
   #:use-module (gnu packages freedesktop)
   #:use-module (gnu packages gnome)
+  #:use-module (gnu packages kde)
+  #:use-module (gnu packages kde-frameworks)
+  #:use-module (gnu packages kde-plasma)
   #:use-module (gnu packages xfce)
   #:use-module (gnu packages avahi)
   #:use-module (gnu packages xdisorg)
@@ -150,6 +155,10 @@
             sugar-desktop-configuration?
             sugar-desktop-service-type
 
+            plasma-desktop-configuration
+            plasma-desktop-configuration?
+            plasma-desktop-service-type
+
             xfce-desktop-configuration
             xfce-desktop-configuration?
             xfce-desktop-service
@@ -1625,6 +1634,50 @@ profile, and extends dbus with the ability for @code{efl} to generate
 thumbnails and makes setuid the programs which enlightenment needs to function
 as expected.")))
 
+;;;
+;;; KDE Plasma desktop service.
+;;;
+
+(define-record-type* <plasma-desktop-configuration> plasma-desktop-configuration
+  make-plasma-desktop-configuration
+  plasma-desktop-configuration?
+  (plasma-package plasma-package (default plasma)))
+
+(define (plasma-polkit-settings config)
+  "Return the list of KDE Plasma dependencies that provide polkit actions and
+rules."
+  (let ((plasma-plasma (plasma-package config)))
+    (map (lambda (name)
+           ((package-direct-input-selector name) plasma-plasma))
+         '("plasma-desktop"
+           "plasma-workspace"
+           "plasma-disks"
+           "kinfocenter"
+           "libksysguard"
+           "ktexteditor"
+           "powerdevil"
+           "plasma-firewall"))))
+
+;; see https://bugs.kde.org/show_bug.cgi?id=456210
+;; if `kde' no exits, fallback to `other', and then unlock lockscreen not work,
+;; so add it.
+(define (plasma-pam-services config)
+  (list (unix-pam-service "kde")))
+
+(define plasma-desktop-service-type
+  (service-type
+   (name 'plasma-desktop)
+   (description "Run the KDE Plasma desktop environment.")
+   (default-value (plasma-desktop-configuration))
+   (extensions
+    (list (service-extension polkit-service-type
+                             plasma-polkit-settings)
+          (service-extension pam-root-service-type
+                             plasma-pam-services)
+          (service-extension profile-service-type
+                             (compose list
+                                      plasma-package))))))
+
 
 ;;;
 ;;; inputattach-service-type