1;;; saveplace.el --- automatically save place in files 2 3;; Copyright (C) 1993, 1994, 2001, 2002, 2003, 2004, 4;; 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Author: Karl Fogel <kfogel@red-bean.com> 7;; Maintainer: FSF 8;; Created: July, 1993 9;; Keywords: bookmarks, placeholders 10 11;; This file is part of GNU Emacs. 12 13;; GNU Emacs is free software; you can redistribute it and/or modify 14;; it under the terms of the GNU General Public License as published by 15;; the Free Software Foundation; either version 2, or (at your option) 16;; any later version. 17 18;; GNU Emacs is distributed in the hope that it will be useful, 19;; but WITHOUT ANY WARRANTY; without even the implied warranty of 20;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21;; GNU General Public License for more details. 22 23;; You should have received a copy of the GNU General Public License 24;; along with GNU Emacs; see the file COPYING. If not, write to the 25;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 26;; Boston, MA 02110-1301, USA. 27 28;;; Commentary: 29 30;; Automatically save place in files, so that visiting them later 31;; (even during a different Emacs session) automatically moves point 32;; to the saved position, when the file is first found. Uses the 33;; value of buffer-local variable save-place to determine whether to 34;; save position or not. 35;; 36;; Thanks to Stefan Schoef, who sent a patch with the 37;; `save-place-version-control' stuff in it. 38 39;;; Code: 40 41;; this is what I was using during testing: 42;; (define-key ctl-x-map "p" 'toggle-save-place) 43 44(defgroup save-place nil 45 "Automatically save place in files." 46 :group 'data) 47 48 49(defvar save-place-alist nil 50 "Alist of saved places to go back to when revisiting files. 51Each element looks like (FILENAME . POSITION); 52visiting file FILENAME goes automatically to position POSITION 53rather than the beginning of the buffer. 54This alist is saved between Emacs sessions.") 55 56(defcustom save-place nil 57 "*Non-nil means automatically save place in each file. 58This means when you visit a file, point goes to the last place 59where it was when you previously visited the same file. 60This variable is automatically buffer-local. 61 62If you wish your place in any file to always be automatically saved, 63simply put this in your `~/.emacs' file: 64 65\(setq-default save-place t) 66\(require 'saveplace) 67 68or else use the Custom facility to set this option." 69 :type 'boolean 70 :require 'saveplace 71 :group 'save-place) 72 73(make-variable-buffer-local 'save-place) 74 75(defcustom save-place-file (convert-standard-filename "~/.emacs-places") 76 "*Name of the file that records `save-place-alist' value." 77 :type 'file 78 :group 'save-place) 79 80(defcustom save-place-version-control nil 81 "*Controls whether to make numbered backups of master save-place file. 82It can have four values: t, nil, `never', and `nospecial'. The first 83three have the same meaning that they do for the variable 84`version-control', and the final value `nospecial' means just use the 85value of `version-control'." 86 :type '(radio (const :tag "Unconditionally" t) 87 (const :tag "For VC Files" nil) 88 (const never) 89 (const :tag "Use value of `version-control'" nospecial)) 90 :group 'save-place) 91 92(defvar save-place-loaded nil 93 "Non-nil means that the `save-place-file' has been loaded.") 94 95(defcustom save-place-limit nil 96 "Maximum number of entries to retain in the list; nil means no limit." 97 :type '(choice (integer :tag "Entries" :value 1) 98 (const :tag "No Limit" nil)) 99 :group 'save-place) 100 101(defcustom save-place-forget-unreadable-files t 102 "Non-nil means forget place in unreadable files. 103 104The filenames in `save-place-alist' that do not match 105`save-place-skip-check-regexp' are filtered through 106`file-readable-p'. if nil, their alist entries are removed. 107 108You may do this anytime by calling the complementary function, 109`save-place-forget-unreadable-files'. When this option is turned on, 110this happens automatically before saving `save-place-alist' to 111`save-place-file'." 112 :type 'boolean :group 'save-place) 113 114(defcustom save-place-save-skipped t 115 "If non-nil, remember files matching `save-place-skip-check-regexp'. 116 117When filtering `save-place-alist' for unreadable files, some will not 118be checked, based on said regexp, and instead saved or forgotten based 119on this flag." 120 :type 'boolean :group 'save-place) 121 122(defcustom save-place-skip-check-regexp 123 ;; thanks to ange-ftp-name-format 124 "\\`/\\(?:cdrom\\|floppy\\|mnt\\|\\(?:[^@/:]*@\\)?[^@/:]*[^@/:.]:\\)" 125 "Regexp whose file names shall not be checked for readability. 126 127When forgetting unreadable files, file names matching this regular 128expression shall not be checked for readability, but instead be 129subject to `save-place-save-skipped'. 130 131Files for which such a check may be inconvenient include those on 132removable and network volumes." 133 :type 'regexp :group 'save-place) 134 135(defun toggle-save-place (&optional parg) 136 "Toggle whether to save your place in this file between sessions. 137If this mode is enabled, point is recorded when you kill the buffer 138or exit Emacs. Visiting this file again will go to that position, 139even in a later Emacs session. 140 141If called with a prefix arg, the mode is enabled if and only if 142the argument is positive. 143 144To save places automatically in all files, put this in your `.emacs' file: 145 146\(setq-default save-place t\)" 147 (interactive "P") 148 (if (not buffer-file-name) 149 (message "Buffer `%s' not visiting a file" (buffer-name)) 150 (if (and save-place (or (not parg) (<= parg 0))) 151 (progn 152 (message "No place will be saved in this file") 153 (setq save-place nil)) 154 (message "Place will be saved") 155 (setq save-place t)))) 156 157(defun save-place-to-alist () 158 ;; put filename and point in a cons box and then cons that onto the 159 ;; front of the save-place-alist, if save-place is non-nil. 160 ;; Otherwise, just delete that file from the alist. 161 ;; first check to make sure alist has been loaded in from the master 162 ;; file. If not, do so, then feel free to modify the alist. It 163 ;; will be saved again when Emacs is killed. 164 (or save-place-loaded (load-save-place-alist-from-file)) 165 (if buffer-file-name 166 (progn 167 (let ((cell (assoc buffer-file-name save-place-alist)) 168 (position (if (not (eq major-mode 'hexl-mode)) 169 (point) 170 (with-no-warnings 171 (1+ (hexl-current-address)))))) 172 (if cell 173 (setq save-place-alist (delq cell save-place-alist))) 174 (if (and save-place 175 (not (= position 1))) ;; Optimize out the degenerate case. 176 (setq save-place-alist 177 (cons (cons buffer-file-name position) 178 save-place-alist))))))) 179 180(defun save-place-forget-unreadable-files () 181 "Remove unreadable files from `save-place-alist'. 182For each entry in the alist, if `file-readable-p' returns nil for the 183filename, remove the entry. Save the new alist \(as the first pair 184may have changed\) back to `save-place-alist'." 185 (interactive) 186 ;; the following was adapted from an in-place filtering function, 187 ;; `filter-mod', used in the original. 188 (unless (null save-place-alist) ;says it better than `when' 189 ;; first, check all except first 190 (let ((fmprev save-place-alist) (fmcur (cdr save-place-alist))) 191 (while fmcur ;not null 192 ;; a value is only saved when it becomes FMPREV. 193 (if (if (string-match save-place-skip-check-regexp (caar fmcur)) 194 save-place-save-skipped 195 (file-readable-p (caar fmcur))) 196 (setq fmprev fmcur) 197 (setcdr fmprev (cdr fmcur))) 198 (setq fmcur (cdr fmcur)))) 199 ;; test first pair, keep it if OK, otherwise 2nd element, which 200 ;; may be '() 201 (unless (if (string-match save-place-skip-check-regexp 202 (caar save-place-alist)) 203 save-place-save-skipped 204 (file-readable-p (caar save-place-alist))) 205 (setq save-place-alist (cdr save-place-alist))))) 206 207(defun save-place-alist-to-file () 208 (let ((file (expand-file-name save-place-file))) 209 (save-excursion 210 (message "Saving places to %s..." file) 211 (set-buffer (get-buffer-create " *Saved Places*")) 212 (delete-region (point-min) (point-max)) 213 (when save-place-forget-unreadable-files 214 (save-place-forget-unreadable-files)) 215 (let ((print-length nil) 216 (print-level nil)) 217 (print save-place-alist (current-buffer))) 218 (let ((version-control 219 (cond 220 ((null save-place-version-control) nil) 221 ((eq 'never save-place-version-control) 'never) 222 ((eq 'nospecial save-place-version-control) version-control) 223 (t 224 t)))) 225 (condition-case nil 226 ;; Don't use write-file; we don't want this buffer to visit it. 227 (write-region (point-min) (point-max) file) 228 (file-error (message "Can't write %s" file))) 229 (kill-buffer (current-buffer)) 230 (message "Saving places to %s...done" file))))) 231 232(defun load-save-place-alist-from-file () 233 (if (not save-place-loaded) 234 (progn 235 (setq save-place-loaded t) 236 (let ((file (expand-file-name save-place-file))) 237 ;; make sure that the alist does not get overwritten, and then 238 ;; load it if it exists: 239 (if (file-readable-p file) 240 (save-excursion 241 (message "Loading places from %s..." file) 242 ;; don't want to use find-file because we have been 243 ;; adding hooks to it. 244 (set-buffer (get-buffer-create " *Saved Places*")) 245 (delete-region (point-min) (point-max)) 246 (insert-file-contents file) 247 (goto-char (point-min)) 248 (setq save-place-alist 249 (car (read-from-string 250 (buffer-substring (point-min) (point-max))))) 251 252 ;; If there is a limit, and we're over it, then we'll 253 ;; have to truncate the end of the list: 254 (if save-place-limit 255 (if (<= save-place-limit 0) 256 ;; Zero gets special cased. I'm not thrilled 257 ;; with this, but the loop for >= 1 is tight. 258 (setq save-place-alist nil) 259 ;; Else the limit is >= 1, so enforce it by 260 ;; counting and then `setcdr'ing. 261 (let ((s save-place-alist) 262 (count 1)) 263 (while s 264 (if (>= count save-place-limit) 265 (setcdr s nil) 266 (setq count (1+ count))) 267 (setq s (cdr s)))))) 268 269 (kill-buffer (current-buffer)) 270 (message "Loading places from %s...done" file))) 271 nil)))) 272 273(defun save-places-to-alist () 274 ;; go through buffer-list, saving places to alist if save-place is 275 ;; non-nil, deleting them from alist if it is nil. 276 (let ((buf-list (buffer-list))) 277 (while buf-list 278 ;; put this into a save-excursion in case someone is counting on 279 ;; another function in kill-emacs-hook to act on the last buffer 280 ;; they were in: 281 (save-excursion 282 (set-buffer (car buf-list)) 283 ;; save-place checks buffer-file-name too, but we can avoid 284 ;; overhead of function call by checking here too. 285 (and buffer-file-name (save-place-to-alist)) 286 (setq buf-list (cdr buf-list)))))) 287 288(defun save-place-find-file-hook () 289 (or save-place-loaded (load-save-place-alist-from-file)) 290 (let ((cell (assoc buffer-file-name save-place-alist))) 291 (if cell 292 (progn 293 (or after-find-file-from-revert-buffer 294 (goto-char (cdr cell))) 295 ;; and make sure it will be saved again for later 296 (setq save-place t))))) 297 298(defun save-place-kill-emacs-hook () 299 ;; First update the alist. This loads the old save-place-file if nec. 300 (save-places-to-alist) 301 ;; Now save the alist in the file, if we have ever loaded the file 302 ;; (including just now). 303 (if save-place-loaded 304 (save-place-alist-to-file))) 305 306(add-hook 'find-file-hook 'save-place-find-file-hook t) 307 308(add-hook 'kill-emacs-hook 'save-place-kill-emacs-hook) 309 310(add-hook 'kill-buffer-hook 'save-place-to-alist) 311 312(provide 'saveplace) ; why not... 313 314;;; arch-tag: 3c2ef47b-0a22-4558-b116-118c9ef454a0 315;;; saveplace.el ends here 316