;;; osc.el --- Support for OSC escape sequences -*- lexical-binding: t; -*-
;; Copyright (C) 2022 Free Software Foundation, Inc.
;; Author: Augusto Stoffel <arstoffel@gmail.com>
;; Matthias Meulien <orontee@gmail.com>
;; Maintainer: emacs-devel@gnu.org
;; Keywords: processes, terminals, services
;; 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 <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Interpretation of OSC (Operating System Commands) escape sequences.
;; Handlers for OSC 2, 7 and 8 (for window title, current directory
;; and hyperlinks respectively) are provided.
;; The function `osc-compilation-filter' can be added to
;; `compilation-filter-hook' to collect OSC sequences in compilation
;; buffers. The variable `osc-for-compilation-buffer' tells what to
;; do with collected sequences.
;;; Code:
(defconst osc-control-seq-regexp
;; See ECMA 48, section 8.3.89 "OSC - OPERATING SYSTEM COMMAND".
"\e\\][\x08-\x0D]*[\x20-\x7E]*\\(\a\\|\e\\\\\\)"
"Regexp matching an OSC control sequence.")
(defun osc-filter-region (begin end)
"Filter out all OSC control sequences from region between BEGIN and END."
(save-excursion
(goto-char begin)
;; Delete escape sequences.
(while (re-search-forward osc-control-seq-regexp end t)
(delete-region (match-beginning 0) (match-end 0)))))
(defvar-local osc-handlers '(("2" . osc-window-title-handler)
("7" . osc-directory-tracker)
("8" . osc-hyperlink-handler))
"Alist of handlers for OSC escape sequences.
See `osc-apply-on-region' for details.")
(defvar-local osc--marker nil)
;; The function `osc-apply-on-region' can set `osc--marker' to the start
;; position of an escape sequence without termination.
(defun osc-apply-on-region (begin end)
"Interpret OSC escape sequences in region between BEGIN and END.
This function searches for escape sequences of the forms
ESC ] command ; text BEL
ESC ] command ; text ESC \\
Every occurrence of such escape sequences is removed from the
buffer. Then, if `command' is a key in the alist that is the value
of the local variable `osc-handlers', that key's value, which should
be a function, is called with `command' and `text' as arguments, with
point where the escape sequence was located."
(save-excursion
(goto-char (or osc--marker begin))
(when (eq (char-before) ?\e) (backward-char))
(while (re-search-forward "\e]" end t)
(let ((pos0 (match-beginning 0))
(code (and (re-search-forward "\\=\\([0-9A-Za-z]*\\);" end t)
(match-string 1)))
(pos1 (point)))
(if (re-search-forward "\a\\|\e\\\\" end t)
(let ((text (buffer-substring-no-properties
pos1 (match-beginning 0))))
(setq osc--marker nil)
(delete-region pos0 (point))
(when-let ((fun (cdr (assoc-string code osc-handlers))))
(funcall fun code text)))
(put-text-property pos0 end 'invisible t)
(setq osc--marker (copy-marker pos0)))))))
;; Window title handling (OSC 2)
(defvar-local osc-window-title nil)
(defun osc-window-title-handler (_ text)
"Set value of `osc-window-title' from an OSC 2 escape sequence.
The variable `osc-window-title' can then be referenced in
`frame-title-format' to dynamically set the frame title.
This function is intended to be included as an element of the
list that is the value of `osc-handlers'."
(setq osc-window-title text))
;; Current directory tracking (OSC 7)
(declare-function url-host "url/url-parse.el")
(declare-function url-type "url/url-parse.el")
(declare-function url-filename "url/url-parse.el")
(defun osc-directory-tracker (_ text)
"Update `default-directory' from OSC 7 escape sequences.
This function is intended to be included as an element of the
the list that is the value of `osc-handlers'. You should arrange
for your shell to print the appropriate escape sequence at each prompt,
such as with the following command:
printf \"\\e]7;file://%s%s\\e\\\\\" \"$HOSTNAME\" \"$PWD\"
This functionality serves as an alternative to `dirtrack-mode'
and `shell-dirtrack-mode'."
(let ((url (url-generic-parse-url text)))
(when (and (string= (url-type url) "file")
(or (null (url-host url))
(string= (url-host url) (system-name))))
(ignore-errors
(cd-absolute (url-unhex-string (url-filename url)))))))
;; Hyperlink handling (OSC 8)
(defvar osc-hyperlink-map
(let ((map (make-sparse-keymap)))
(define-key map "\C-c\r" 'browse-url-button-open)
(define-key map [mouse-2] 'browse-url-button-open)
(define-key map [follow-link] 'mouse-face)
map)
"Keymap used by OSC 8 hyperlink buttons.")
(define-button-type 'osc-hyperlink
'keymap osc-hyperlink-map
'help-echo (lambda (_ buffer pos)
(when-let ((url (get-text-property pos 'browse-url-data buffer)))
(format "mouse-2, C-c RET: Open %s" url))))
(defvar-local osc-hyperlink--state nil)
(defun osc-hyperlink-handler (_ text)
"Create a hyperlink from an OSC 8 escape sequence.
This function is intended to be included as an elemnt of the list
that is the value of `osc-handlers'."
(when osc-hyperlink--state
(let ((start (car osc-hyperlink--state))
(url (cdr osc-hyperlink--state)))
(make-text-button start (point)
'type 'osc-hyperlink
'browse-url-data url)))
(setq osc-hyperlink--state
(and (string-match ";\\(.+\\)" text)
(cons (point-marker) (match-string-no-properties 1 text)))))
(defcustom osc-for-compilation-buffer 'filter
"What to do with OSC escape sequences in compilation output.
If nil, do nothing.
If the symbol `filter', then filter out all OSC control sequences.
If any other non-nil value, then collect OSC control sequences
and call the appropriate handlers as described in `osc-handlers'.
In order for this to have any effect, `osc-compilation-filter'
must be in `compilation-filter-hook'."
:type '(choice (const :tag "Do nothing" nil)
(const :tag "Filter out OSC" filter)
(other :tag "Translate OSC" t))
:group 'osc
:version "29.1")
(defvar compilation-filter-start)
;;;###autoload
(defun osc-compilation-filter ()
"Maybe collect OSC control sequences.
This function depends on the variable `osc-for-compilation-buffer',
and is meant to be used in `compilation-filter-hook'."
(let ((inhibit-read-only t))
(pcase osc-for-compilation-buffer
('nil nil)
('filter
(osc-filter-region compilation-filter-start (point)))
(_
(osc-apply-on-region compilation-filter-start (point))))))
(provide 'osc)
;;; osc.el ends here