From: Mark Oteiza <mvoteiza@udel.edu>
To: Eli Zaretskii <eliz@gnu.org>
Cc: cpitclaudel@gmail.com, emacs-devel@gnu.org
Subject: Library for XDG things (was Re: [PATCH] checking eww download directory)
Date: Sat, 28 Jan 2017 20:01:50 -0500 [thread overview]
Message-ID: <20170129010150.GB16992@holos.localdomain> (raw)
In-Reply-To: <83r33nzkkx.fsf@gnu.org>
On 28/01/17 at 09:53am, Eli Zaretskii wrote:
> > From: Mark Oteiza <mvoteiza@udel.edu>
> > Date: Fri, 27 Jan 2017 15:17:10 -0500
> > Cc: emacs-devel@gnu.org
> >
> > > How hard would it be to integrate with the xdg-user-dirs standard
> > > instead? On many GNU/Linux systems, running "xdg-user-dir DOWNLOAD" is
> > > enough (http://stackoverflow.com/questions/13161226/). This would
> > > make eww consistent with Firefox, too (they take the slightly more
> > > painful route of parsing ~/.config/user-dirs.dirs:
> > > https://dxr.mozilla.org/mozilla-release/source/xpcom/io/SpecialSystemDirectory.cpp#256)
> >
> > An xdg.el would be nice to have for elisp that interfaces
> > with XDG-following things. mpc.el and image-dired.el are two files that
> > come to mind: mpd follows [0], image-dired
> > supports [1]. Actually, it looks like those are the only two files with
> > XDG bits, and I put them there. How about that.
> >
> > Anyways, these aren't difficult to implement. If it would be a welcome
> > addition I'd have a go at writing it.
> >
> > [0] https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
> > [1] https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html
>
> This has come up before. I think this would be welcome, but one issue
> that didn't get resolved is how much of that should be automatic
> (i.e. should Emacs automatically search certain directories for
> certain kinds of files), and if so, how to split the imaginary xdg.el
> into two parts, with the automatic part living in some preloaded file
> (probably files.el). There's also the issue of whether users and/or
> Lisp programs should be able to disable this search (e.g., by binding
> some variable).
Sounds like a daunting goal. I imagine having XDG bits preloaded would
only really be necessary if Emacs decided it was going to follow the
base directory spec (and probably only on GNU/Linux).
In the mean time, the following is a small library of some useful
functions. At least for the base directory spec it remains rather low
level as the standard gives a lot of freedom to how applications want to
handle multiple locations of config/data:
;;; xdg.el --- XDG specification and standard library -*- lexical-binding: t -*-
;; Copyright (C) 2017 Mark Oteiza <mvoteiza@udel.edu>
;; Author: Mark Oteiza <mvoteiza@udel.edu>
;; Keywords: files, data
;; This program 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.
;; This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;; Library providing some convenience functions for the following XDG
;; standards and specifications
;;
;; - XDG Base Directory Specification
;; - Thumbnail Managing Standard
;; - xdg-user-dirs configuration
;;; Code:
\f
;; XDG Base Directory Specification
;; https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
(defmacro xdg--dir-home (environ default-path)
(declare (debug (stringp stringp)))
(let ((env (make-symbol "env")))
`(let ((,env (getenv ,environ)))
(if (or (null ,env) (not (file-name-absolute-p ,env)))
(expand-file-name ,default-path)
,env))))
(defun xdg-config-home ()
"Return the base directory for user specific configuration files."
(xdg--dir-home "XDG_CONFIG_HOME" "~/.config"))
(defun xdg-cache-home ()
"Return the base directory for user specific cache files."
(xdg--dir-home "XDG_CACHE_HOME" "~/.cache"))
(defun xdg-data-home ()
"Return the base directory for user specific data files."
(xdg--dir-home "XDG_DATA_HOME" "~/.local/share"))
(defun xdg-runtime-dir ()
"Return the value of $XDG_RUNTIME_DIR."
(getenv "XDG_RUNTIME_DIR"))
(defun xdg-config-dirs ()
"Return the config directory search path as a list."
(let ((env (getenv "XDG_CONFIG_DIRS")))
(if (or (null env) (string= env ""))
'("/etc/xdg")
(parse-colon-path env))))
(defun xdg-data-dirs ()
"Return the data directory search path as a list."
(let ((env (getenv "XDG_CONFIG_DIRS")))
(if (or (null env) (string= env ""))
'("/usr/local/share/" "/usr/share/")
(parse-colon-path env))))
\f
;; Thumbnail Managing Standard
;; https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html
(defun xdg-thumb-uri (filename)
"Return the canonical URI for FILENAME.
If FILENAME has absolute path /foo/bar.jpg, its canonical URI is
file:///foo/bar.jpg"
(concat "file://" (expand-file-name filename)))
(defun xdg-thumb-name (filename)
"Return the appropriate thumbnail filename for FILENAME."
(concat (md5 (xdg-thumb-uri filename)) ".png"))
(defun xdg-thumb-mtime (filename)
"Return modification time of FILENAME as integral seconds from the epoch."
(floor (float-time (nth 5 (file-attributes filename)))))
\f
;; XDG User Directories
;; https://www.freedesktop.org/wiki/Software/xdg-user-dirs/
(defconst xdg-line-regexp
(eval-when-compile
(rx "XDG_"
(group-n 1 (or "DESKTOP" "DOWNLOAD" "TEMPLATES" "PUBLICSHARE"
"DOCUMENTS" "MUSIC" "PICTURES" "VIDEOS"))
"_DIR=\""
(group-n 2 (or "/" "$HOME/") (*? (or (not (any "\"")) "\\\"")))
"\""))
"Regexp matching non-comment lines in xdg-user-dirs config files.")
(defvar xdg-user-dirs nil
"Alist of directory keys and values.")
(defun xdg--user-dirs-parse-line ()
"Return pair of user-dirs key to directory value in LINE, otherwise nil.
This should be called at the beginning of a line."
(skip-chars-forward "[:blank:]")
(when (and (/= (following-char) ?#)
(looking-at xdg-line-regexp))
(let ((k (match-string 1))
(v (match-string 2)))
(when (and k v) (cons k v)))))
(defun xdg--user-dirs-parse-file (filename)
"Return alist of xdg-user-dirs from FILENAME."
(let (elt res)
(with-temp-buffer
(insert-file-contents filename)
(goto-char (point-min))
(while (not (eobp))
(setq elt (xdg--user-dirs-parse-line))
(when (consp elt) (push elt res))
(forward-line)))
res))
(defun xdg-user-dir (name)
"Return the path of user directory referred to by NAME."
(when (null xdg-user-dirs)
(setq xdg-user-dirs
(xdg--user-dirs-parse-file
(expand-file-name "user-dirs.dirs" (xdg-config-home)))))
(cdr (assoc name xdg-user-dirs)))
(provide 'xdg)
;;; xdg.el ends here
next prev parent reply other threads:[~2017-01-29 1:01 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-27 19:10 [PATCH] checking eww download directory Mark Oteiza
2017-01-27 19:21 ` Lars Ingebrigtsen
2017-01-27 19:48 ` Mark Oteiza
2017-01-27 20:10 ` Eli Zaretskii
2017-01-28 8:01 ` Yuri Khan
2017-01-28 8:54 ` Eli Zaretskii
2017-01-28 14:14 ` Lars Ingebrigtsen
2017-01-28 21:04 ` Mark Oteiza
2017-01-27 19:27 ` Lars Ingebrigtsen
2017-01-27 19:38 ` Clément Pit-Claudel
2017-01-27 20:17 ` Mark Oteiza
2017-01-27 22:21 ` Clément Pit-Claudel
2017-01-28 7:53 ` Eli Zaretskii
2017-01-29 1:01 ` Mark Oteiza [this message]
2017-01-30 14:40 ` Library for XDG things (was Re: [PATCH] checking eww download directory) Ted Zlatanov
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