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org-mode/lisp/ob-screen.el
2021-01-01 15:02:10 -05:00

144 lines
5.4 KiB
EmacsLisp

;;; ob-screen.el --- Babel Support for Interactive Terminal -*- lexical-binding: t; -*-
;; Copyright (C) 2009-2021 Free Software Foundation, Inc.
;; Author: Benjamin Andresen
;; Maintainer: Ken Mankoff
;; Keywords: literate programming, interactive shell
;; Homepage: https://orgmode.org
;; 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:
;; Org-Babel support for interactive terminals. Mostly shell scripts.
;; Heavily inspired by 'eev' from Eduardo Ochs
;;
;; Adding :cmd and :terminal as header arguments
;; :terminal must support the -T (title) and -e (command) parameter
;;
;; You can test the default setup. (xterm + sh) with
;; M-x org-babel-screen-test RET
;;; Code:
(require 'ob)
(defvar org-babel-screen-location "screen"
"The command location for screen.
In case you want to use a different screen than one selected by your $PATH")
(defvar org-babel-default-header-args:screen
`((:results . "silent") (:session . "default") (:cmd . "sh")
(:terminal . "xterm") (:screenrc . ,null-device))
"Default arguments to use when running screen source blocks.")
(defun org-babel-execute:screen (body params)
"Send a block of code via screen to a terminal using Babel.
\"default\" session is used when none is specified."
(message "Sending source code block to interactive terminal session...")
(save-window-excursion
(let* ((session (cdr (assq :session params)))
(socket (org-babel-screen-session-socketname session)))
(unless socket (org-babel-prep-session:screen session params))
(org-babel-screen-session-execute-string
session (org-babel-expand-body:generic body params)))))
(defun org-babel-prep-session:screen (_session params)
"Prepare SESSION according to the header arguments specified in PARAMS."
(let* ((session (cdr (assq :session params)))
(cmd (cdr (assq :cmd params)))
(terminal (cdr (assq :terminal params)))
(screenrc (cdr (assq :screenrc params)))
(process-name (concat "org-babel: terminal (" session ")")))
(apply 'start-process process-name "*Messages*"
terminal `("-T" ,(concat "org-babel: " session) "-e" ,org-babel-screen-location
"-c" ,screenrc "-mS" ,session ,cmd))
;; XXX: Is there a better way than the following?
(while (not (org-babel-screen-session-socketname session))
;; wait until screen session is available before returning
)))
;; helper functions
(defun org-babel-screen-session-execute-string (session body)
"If SESSION exists, send BODY to it."
(let ((socket (org-babel-screen-session-socketname session)))
(when socket
(let ((tmpfile (org-babel-screen-session-write-temp-file session body)))
(apply 'start-process (concat "org-babel: screen (" session ")") "*Messages*"
org-babel-screen-location
`("-S" ,socket "-X" "eval" "msgwait 0"
,(concat "readreg z " tmpfile)
"paste z"))))))
(defun org-babel-screen-session-socketname (session)
"Check if SESSION exists by parsing output of \"screen -ls\"."
(let* ((screen-ls (shell-command-to-string "screen -ls"))
(sockets (delq
nil
(mapcar
(lambda (x)
(when (string-match (rx (or "(Attached)" "(Detached)")) x)
x))
(split-string screen-ls "\n"))))
(match-socket (car
(delq
nil
(mapcar
(lambda (x)
(and (string-match-p (regexp-quote session) x)
x))
sockets)))))
(when match-socket (car (split-string match-socket)))))
(defun org-babel-screen-session-write-temp-file (_session body)
"Save BODY in a temp file that is named after SESSION."
(let ((tmpfile (org-babel-temp-file "screen-")))
(with-temp-file tmpfile
(insert body)
(insert "\n")
;; org-babel has superfluous spaces
(goto-char (point-min))
(delete-matching-lines "^ +$"))
tmpfile))
(defun org-babel-screen-test ()
"Test if the default setup works.
The terminal should shortly flicker."
(interactive)
(let* ((random-string (format "%s" (random 99999)))
(tmpfile (org-babel-temp-file "ob-screen-test-"))
(body (concat "echo '" random-string "' > " tmpfile "\nexit\n"))
tmp-string)
(org-babel-execute:screen body org-babel-default-header-args:screen)
;; XXX: need to find a better way to do the following
(while (not (file-readable-p tmpfile))
;; do something, otherwise this will be optimized away
(message "org-babel-screen: File not readable yet."))
(setq tmp-string (with-temp-buffer
(insert-file-contents-literally tmpfile)
(buffer-substring (point-min) (point-max))))
(delete-file tmpfile)
(message (concat "org-babel-screen: Setup "
(if (string-match random-string tmp-string)
"WORKS."
"DOESN'T work.")))))
(provide 'ob-screen)
;;; ob-screen.el ends here