;;; pcmpl-linux.el --- functions for dealing with GNU/Linux completions -*- lexical-binding: t -*-
;; Copyright (C) 1999-2022 Free Software Foundation, Inc.
;; Package: pcomplete
;; 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 <https://www.gnu.org/licenses/>.
;;; Commentary:
;; These functions are for use with GNU/Linux. Since they depend on a
;; certain knowledge of the layout of such systems, they probably
;; won't work very well on other operating systems.
;;; Code:
(provide 'pcmpl-linux)
(require 'pcomplete)
(eval-when-compile (require 'rx))
;; Functions:
;;;###autoload
(defun pcomplete/kill ()
"Completion for GNU/Linux `kill', using /proc filesystem."
(if (pcomplete-match "^-\\(.*\\)" 0)
(pcomplete-here
(pcomplete-uniquify-list
(split-string
(pcomplete-process-result "kill" "-l")))
(pcomplete-match-string 1 0)))
(while (pcomplete-here
(if (file-directory-p "/proc")
(directory-files "/proc" nil "\\`[0-9]+\\'"))
nil #'identity)))
;;;###autoload
(defun pcomplete/umount ()
"Completion for GNU/Linux `umount'."
(pcomplete-opt "hVafrnvt(pcmpl-linux-fs-types)")
(while (pcomplete-here (pcmpl-linux-mounted-directories)
nil #'identity)))
;;;###autoload
(defun pcomplete/mount ()
"Completion for GNU/Linux `mount'."
(pcomplete-opt "hVanfFrsvwt(pcmpl-linux-fs-types)o?L?U?")
(while (pcomplete-here (pcomplete-entries) nil #'identity)))
(defconst pcmpl-linux-fs-modules-path-format "/lib/modules/%s/kernel/fs/")
(defun pcmpl-linux-fs-types ()
"Return a list of available fs modules on GNU/Linux systems."
(let ((kernel-ver (pcomplete-process-result "uname" "-r")))
(directory-files
(format pcmpl-linux-fs-modules-path-format kernel-ver))))
(defconst pcmpl-linux-mtab-file "/etc/mtab")
(defun pcmpl-linux-mounted-directories ()
"Return a list of mounted directory names."
(let (points)
(when (file-readable-p pcmpl-linux-mtab-file)
(with-temp-buffer
(insert-file-contents-literally pcmpl-linux-mtab-file)
(while (not (eobp))
(let* ((line (buffer-substring (point) (line-end-position)))
(args (split-string line " ")))
(setq points (cons (nth 1 args) points)))
(forward-line)))
(pcomplete-uniquify-list points))))
(defun pcomplete-pare-list (l r)
"Destructively remove from list L all elements matching any in list R.
Test is done using `equal'."
(while (and l (and r (member (car l) r)))
(setq l (cdr l)))
(let ((m l))
(while m
(while (and (cdr m)
(and r (member (cadr m) r)))
(setcdr m (cddr m)))
(setq m (cdr m))))
l)
(defun pcmpl-linux-mountable-directories ()
"Return a list of mountable directory names."
(let (points)
(when (file-readable-p "/etc/fstab")
(with-temp-buffer
(insert-file-contents-literally "/etc/fstab")
(while (not (eobp))
(let* ((line (buffer-substring (point) (line-end-position)))
(args (split-string line "\\s-+")))
(setq points (cons (nth 1 args) points)))
(forward-line)))
(pcomplete-pare-list
(pcomplete-uniquify-list points)
(cons "swap" (pcmpl-linux-mounted-directories))))))
;;; systemd
(defun pcmpl-linux--systemd-units (&rest args)
"Run `systemd list-units ARGS' and return the output as a list."
(with-temp-buffer
(apply #'call-process
"systemctl" nil '(t nil) nil
"list-units" "--full" "--legend=no" "--plain" args)
(goto-char (point-min))
(let (result)
(while (re-search-forward (rx bol (group (+ (not space)))
(+ space) (+ (not space))
(+ space) (group (+ (not space)))
(+ space) (+ (not space))
(+ space) (group (* nonl)))
nil t)
(push (match-string 1) result)
(put-text-property 0 1 'pcomplete-annotation
(concat " " (match-string 2))
(car result))
(put-text-property 0 1 'pcomplete-description
(match-string 3)
(car result)))
(nreverse result))))
;;;###autoload
(defun pcomplete/systemctl ()
"Completion for the `systemctl' command."
(let ((subcmds (pcomplete-from-help
"systemctl --help"
:margin (rx bol " " (group) alpha)
:argument (rx (+ (any alpha ?-)))
:metavar (rx (group (+ " " (>= 2 (any upper "[]|."))))))))
(while (not (member (pcomplete-arg 1) subcmds))
(if (string-prefix-p "-" (pcomplete-arg 0))
(pcomplete-here (pcomplete-from-help "systemctl --help"
:metavar "[^ ]+"
:separator " \\(\\)-"))
(pcomplete-here subcmds)))
(let ((subcmd (pcomplete-arg 1))
(context (if (member "--user" pcomplete-args) "--user" "--system")))
(while (pcase subcmd
((guard (string-prefix-p "-" (pcomplete-arg 0)))
(pcomplete-here
(pcomplete-from-help "systemctl --help")))
;; TODO: suggest only relevant units to each subcommand
("start"
(pcomplete-here
(pcmpl-linux--systemd-units context "--state" "inactive,failed")))
((or "restart" "stop")
(pcomplete-here
(pcmpl-linux--systemd-units context "--state" "active")))
(_ (pcomplete-here
(completion-table-in-turn
(pcmpl-linux--systemd-units context "--all")
(pcomplete-entries)))))))))
;;;###autoload
(defun pcomplete/journalctl ()
"Completion for the `journalctl' command."
(while (if (string-prefix-p "-" (pcomplete-arg 0))
(pcomplete-here (pcomplete-from-help "journalctl --help"
:metavar "[^ ]+"
:separator " \\(\\)-"))
(pcomplete-here (mapcar (lambda (s) (concat s "="))
(process-lines "journalctl" "--fields"))))))
;;; pcmpl-linux.el ends here