;;; ob-comint.el --- org-babel functions for interaction with comint buffers

;; Copyright (C) 2009-2013 Free Software Foundation, Inc.

;; Author: Eric Schulte
;; Keywords: literate programming, reproducible research, comint
;; Homepage: http://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 <http://www.gnu.org/licenses/>.

;;; Commentary:

;; These functions build on comint to ease the sending and receiving
;; of commands and results from comint buffers.

;; Note that the buffers in this file are analogous to sessions in
;; org-babel at large.

;;; Code:
(require 'ob)
(require 'org-compat)
(require 'comint)
(eval-when-compile (require 'cl))
(declare-function with-parsed-tramp-file-name "tramp" (filename var &rest body))
(declare-function tramp-flush-directory-property "tramp" (vec directory))

(defun org-babel-comint-buffer-livep (buffer)
  "Check if BUFFER is a comint buffer with a live process."
  (let ((buffer (if buffer (get-buffer buffer))))
    (and buffer (buffer-live-p buffer) (get-buffer-process buffer) buffer)))

(defmacro org-babel-comint-in-buffer (buffer &rest body)
  "Check BUFFER and execute BODY.
BUFFER is checked with `org-babel-comint-buffer-livep'.  BODY is
executed inside the protection of `save-excursion' and
`save-match-data'."
  (declare (indent 1))
  `(save-excursion
     (save-match-data
       (unless (org-babel-comint-buffer-livep ,buffer)
         (error "Buffer %s does not exist or has no process" ,buffer))
       (set-buffer ,buffer)
       ,@body)))
(def-edebug-spec org-babel-comint-in-buffer (form body))

(defmacro org-babel-comint-with-output (meta &rest body)
  "Evaluate BODY in BUFFER and return process output.
Will wait until EOE-INDICATOR appears in the output, then return
all process output.  If REMOVE-ECHO and FULL-BODY are present and
non-nil, then strip echo'd body from the returned output.  META
should be a list containing the following where the last two
elements are optional.

 (BUFFER EOE-INDICATOR REMOVE-ECHO FULL-BODY)

This macro ensures that the filter is removed in case of an error
or user `keyboard-quit' during execution of body."
  (declare (indent 1))
  (let ((buffer (car meta))
	(eoe-indicator (cadr meta))
	(remove-echo (cadr (cdr meta)))
	(full-body (cadr (cdr (cdr meta)))))
    `(org-babel-comint-in-buffer ,buffer
       (let ((string-buffer "") dangling-text raw)
	 ;; setup filter
	 (setq comint-output-filter-functions
	       (cons (lambda (text) (setq string-buffer (concat string-buffer text)))
		     comint-output-filter-functions))
	 (unwind-protect
	     (progn
	       ;; got located, and save dangling text
	       (goto-char (process-mark (get-buffer-process (current-buffer))))
	       (let ((start (point))
		     (end (point-max)))
		 (setq dangling-text (buffer-substring start end))
		 (delete-region start end))
	       ;; pass FULL-BODY to process
	       ,@body
	       ;; wait for end-of-evaluation indicator
	       (while (progn
			(goto-char comint-last-input-end)
			(not (save-excursion
			       (and (re-search-forward
				     (regexp-quote ,eoe-indicator) nil t)
				    (re-search-forward
				     comint-prompt-regexp nil t)))))
		 (accept-process-output (get-buffer-process (current-buffer)))
		 ;; thought the following this would allow async
		 ;; background running, but I was wrong...
		 ;; (run-with-timer .5 .5 'accept-process-output
		 ;; 		 (get-buffer-process (current-buffer)))
		 )
	       ;; replace cut dangling text
	       (goto-char (process-mark (get-buffer-process (current-buffer))))
	       (insert dangling-text))
	   ;; remove filter
	   (setq comint-output-filter-functions
		 (cdr comint-output-filter-functions)))
	 ;; remove echo'd FULL-BODY from input
	 (if (and ,remove-echo ,full-body
		  (string-match
		   (replace-regexp-in-string
		    "\n" "[\r\n]+" (regexp-quote (or ,full-body "")))
		   string-buffer))
	     (setq raw (substring string-buffer (match-end 0))))
	 (split-string string-buffer comint-prompt-regexp)))))
(def-edebug-spec org-babel-comint-with-output (form body))

(defun org-babel-comint-input-command (buffer cmd)
  "Pass CMD to BUFFER.
The input will not be echoed."
  (org-babel-comint-in-buffer buffer
    (goto-char (process-mark (get-buffer-process buffer)))
    (insert cmd)
    (comint-send-input)
    (org-babel-comint-wait-for-output buffer)))

(defun org-babel-comint-wait-for-output (buffer)
  "Wait until output arrives from BUFFER.
Note: this is only safe when waiting for the result of a single
statement (not large blocks of code)."
  (org-babel-comint-in-buffer buffer
    (while (progn
             (goto-char comint-last-input-end)
             (not (and (re-search-forward comint-prompt-regexp nil t)
                       (goto-char (match-beginning 0))
                       (string= (face-name (face-at-point))
                                "comint-highlight-prompt"))))
      (accept-process-output (get-buffer-process buffer)))))

(defun org-babel-comint-eval-invisibly-and-wait-for-file
  (buffer file string &optional period)
  "Evaluate STRING in BUFFER invisibly.
Don't return until FILE exists.  Code in STRING must ensure that
FILE exists at end of evaluation."
  (unless (org-babel-comint-buffer-livep buffer)
    (error "Buffer %s does not exist or has no process" buffer))
  (if (file-exists-p file) (delete-file file))
  (process-send-string
   (get-buffer-process buffer)
   (if (string-match "\n$" string) string (concat string "\n")))
  ;; From Tramp 2.1.19 the following cache flush is not necessary
  (if (file-remote-p default-directory)
      (let (v)
	(with-parsed-tramp-file-name default-directory nil
				     (tramp-flush-directory-property v ""))))
  (while (not (file-exists-p file)) (sit-for (or period 0.25))))

(provide 'ob-comint)



;;; ob-comint.el ends here
