;;; savebuflist.el --- functions to save/restore a "session"

;;; Copyright (c) 2002, Brian St. Pierre <bstpierre @ bstpierre.org>

;;; Permission to use, copy, modify, and distribute this software and its
;;; documentation for any purpose, without fee, and without a written agreement
;;; is hereby granted, provided that the above copyright notice and this
;;; paragraph and the following two paragraphs appear in all copies.
;;;
;;; IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
;;; INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST
;;; PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION,
;;; EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;;;
;;; THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
;;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
;;; PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
;;; BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
;;; SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

;;; Author: Brian St. Pierre
;;; Maintainer: Brian St. Pierre <bstpierre @ bstpierre.org>
;;; Keywords: session, buffer list
;;; Created: 2002-04-22
;;; Modified: 2002-10-25 (v 0.2)
;;;
;;; 2003-07-09 v 0.3
;;;  - Leaning more towards "session management".
;;;  - Added savebuflist-close.
;;;  - Created savebuflist prefix keymap (C-c s <key>)

(defun savebuflist-save (save-name)
  "Save a list of buffers currently visiting files to filename."
  (interactive "FSave buflist to: ")
  (let ((oldbuf (current-buffer))
        (n 0))
    (save-current-buffer
      (set-buffer (get-buffer-create "*savebuflist*"))
      (erase-buffer)
      (while (< n (length (buffer-list)))
        (let ((buf-filename (buffer-file-name (nth n (buffer-list)))))
          (if buf-filename
              (progn
                (beginning-of-line)
                (insert buf-filename)
                (newline))
              ) ; end if
          ) ; end let file
        (setq n (+ n 1))
        ) ; end while
      (write-file save-name)
      (kill-buffer (current-buffer))
      ) ; end save-current-buffer
    ) ; end let oldbuf/n
  ) ; end defun


(defun savebuflist-restore (filename)
  "Close current session, load buffers in previously saved session."
  (interactive "fLoad buflist from: ")
  (savebuflist-close)
  (let ((oldbuf (current-buffer))
        (n 0))
    (save-current-buffer
      (set-buffer (find-file-noselect filename))
      (while (not (eobp))
        (let ((buf-filename (substring (thing-at-point 'line) 0 -1)))
          (cond
           ((eq buf-filename filename) nil)
           ((not (file-readable-p buf-filename))
            (message (concat "Can't read " buf-filename ".")))
           ((string= (file-name-nondirectory buf-filename) "TAGS")
            (visit-tags-table buf-filename))
           (t (find-file-noselect buf-filename))
           ) ; end cond
          ) ; end let buf-filename
        (forward-line)
        ) ; end while
      (kill-buffer (current-buffer))
      ) ; end save-current-buffer
    ) ; end let oldbuf/n
  (buffer-menu)
  ) ; end defun

(defun savebuflist-close ()
  "Close all buffers that are visiting a file."
  (interactive)
  (let (
        (buflist (buffer-list))
        (n 0))
    (while (< n (length buflist))
      (let* ((buf (nth n buflist))
             (buf-filename (buffer-file-name buf)))
        (if (and buf-filename (not (buffer-modified-p buf)))
            (kill-buffer buf))
        ) ; end let buf/buf-filename
      (setq n (+ n 1))
      ) ; end while
    ) ; end let buflist/n
  ) ; end defun

;;; Session Management
;;;
;;; These use savebuflist.el.
;;; FIXME: allow customization.
(defvar savebuflist-prefix-map (make-sparse-keymap))
(defvar savebuflist-prefix-key "\C-cs")
(define-prefix-command 'savebuflist-prefix-map)
(global-set-key savebuflist-prefix-key savebuflist-prefix-map)

(define-key savebuflist-prefix-map "r" 'savebuflist-restore)
(define-key savebuflist-prefix-map "s" 'savebuflist-save)
(define-key savebuflist-prefix-map "c" 'savebuflist-close)

(provide 'savebuflist)