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1 | ;;; saveplace.el --- automatically save place in files. |
2 | ||
e7dc77f6 | 3 | ;; Copyright (C) 1993, 1994 Free Software Foundation, Inc. |
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4 | |
5 | ;; Author: Karl Fogel <kfogel@cs.oberlin.edu> | |
6 | ;; Maintainer: FSF | |
7 | ;; Created: July, 1993 | |
b6ace927 | 8 | ;; Version: 1.2 |
722074ef RS |
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 | |
b578f267 EN |
24 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
25 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
26 | ;; Boston, MA 02111-1307, USA. | |
27 | ||
28 | ;;; Commentary: | |
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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 | ;; | |
e7dc77f6 RS |
36 | ;; Thanks to Stefan Schoef, who sent a patch with the |
37 | ;; `save-place-version-control' stuff in it. | |
722074ef | 38 | |
b578f267 EN |
39 | ;;; Code: |
40 | ||
722074ef RS |
41 | ;; this is what I was using during testing: |
42 | ;; (define-key ctl-x-map "p" 'toggle-save-place) | |
43 | ||
44 | (defvar save-place-alist nil | |
45 | "Alist of saved places to go back to when revisiting files. | |
46 | Each element looks like (FILENAME . POSITION); | |
47 | visiting file FILENAME goes automatically to position POSITION | |
48 | rather than the beginning of the buffer. | |
49 | This alist is saved between Emacs sessions.") | |
50 | ||
51 | (defvar save-place nil | |
52 | "*Non-nil means automatically save place in each file. | |
53 | This means when you visit a file, point goes to the last place | |
54 | where it was when you previously visited the same file. | |
55 | This variable is automatically buffer-local. | |
56 | ||
57 | If you wish your place in any file to always be automatically saved, | |
58 | simply put this in your `~/.emacs' file: | |
59 | ||
60 | \(setq-default save-place t\)") | |
61 | ||
62 | (make-variable-buffer-local 'save-place) | |
63 | ||
0d448e33 | 64 | (defvar save-place-file (convert-standard-filename "~/.emacs-places") |
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65 | "*Name of the file that records `save-place-alist' value.") |
66 | ||
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67 | (defvar save-place-version-control 'nospecial |
68 | "*Controls whether to make numbered backups of master save-place file. | |
69 | It can have four values: t, nil, `never', and `nospecial'. The first | |
70 | three have the same meaning that they do for the variable | |
71 | `version-control', and the final value `nospecial' means just use the | |
72 | value of `version-control'.") | |
73 | ||
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74 | (defvar save-place-loaded nil |
75 | "Non-nil means that the `save-place-file' has been loaded.") | |
76 | ||
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77 | (defvar save-place-limit nil |
78 | "Maximum number of entries to retain in the list; nil means no limit.") | |
79 | ||
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80 | (defun toggle-save-place (&optional parg) |
81 | "Toggle whether to save your place in this file between sessions. | |
82 | If this mode is enabled, point is recorded when you kill the buffer | |
83 | or exit Emacs. Visiting this file again will go to that position, | |
84 | even in a later Emacs session. | |
85 | ||
86 | If called with a prefix arg, the mode is enabled if and only if | |
87 | the argument is positive. | |
88 | ||
89 | To save places automatically in all files, put this in your `.emacs' file: | |
90 | ||
91 | \(setq-default save-place t\)" | |
92 | (interactive "P") | |
93 | (if (not buffer-file-name) | |
44a75d48 | 94 | (message "Buffer `%s' not visiting a file" (buffer-name)) |
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95 | (if (and save-place (or (not parg) (<= parg 0))) |
96 | (progn | |
44a75d48 | 97 | (message "No place will be saved in this file") |
722074ef | 98 | (setq save-place nil)) |
44a75d48 | 99 | (message "Place will be saved") |
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100 | (setq save-place t)))) |
101 | ||
102 | (defun save-place-to-alist () | |
103 | ;; put filename and point in a cons box and then cons that onto the | |
104 | ;; front of the save-place-alist, if save-place is non-nil. | |
105 | ;; Otherwise, just delete that file from the alist. | |
106 | ;; first check to make sure alist has been loaded in from the master | |
107 | ;; file. If not, do so, then feel free to modify the alist. It | |
108 | ;; will be saved again when Emacs is killed. | |
109 | (or save-place-loaded (load-save-place-alist-from-file)) | |
110 | (if buffer-file-name | |
111 | (progn | |
112 | (let ((cell (assoc buffer-file-name save-place-alist))) | |
113 | (if cell | |
114 | (setq save-place-alist (delq cell save-place-alist)))) | |
115 | (if save-place | |
116 | (setq save-place-alist | |
19d0c48a RS |
117 | (cons (cons buffer-file-name |
118 | (if (not (eq major-mode 'hexl-mode)) | |
119 | (point) | |
120 | (1+ (hexl-current-address)))) | |
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121 | save-place-alist)))))) |
122 | ||
123 | (defun save-place-alist-to-file () | |
124 | (let ((file (expand-file-name save-place-file))) | |
125 | (save-excursion | |
b483a3c1 | 126 | (message "Saving places to %s..." file) |
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127 | (set-buffer (get-buffer-create " *Saved Places*")) |
128 | (delete-region (point-min) (point-max)) | |
129 | (if (file-readable-p file) | |
130 | (insert-file-contents file)) | |
131 | (delete-region (point-min) (point-max)) | |
132 | (goto-char (point-min)) | |
133 | (print save-place-alist (current-buffer)) | |
e7dc77f6 RS |
134 | (let ((version-control |
135 | (cond | |
136 | ((null save-place-version-control) nil) | |
137 | ((eq 'never save-place-version-control) 'never) | |
138 | ((eq 'nospecial save-place-version-control) version-control) | |
139 | (t | |
140 | t)))) | |
141 | (write-file file) | |
142 | (kill-buffer (current-buffer)) | |
b483a3c1 | 143 | (message "Saving places to %s...done" file))))) |
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144 | |
145 | (defun load-save-place-alist-from-file () | |
146 | (if (not save-place-loaded) | |
147 | (progn | |
148 | (setq save-place-loaded t) | |
149 | (let ((file (expand-file-name save-place-file))) | |
150 | ;; make sure that the alist does not get overwritten, and then | |
151 | ;; load it if it exists: | |
152 | (if (file-readable-p file) | |
153 | (save-excursion | |
b483a3c1 | 154 | (message "Loading places from %s..." save-place-file) |
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155 | ;; don't want to use find-file because we have been |
156 | ;; adding hooks to it. | |
157 | (set-buffer (get-buffer-create " *Saved Places*")) | |
158 | (delete-region (point-min) (point-max)) | |
159 | (insert-file-contents file) | |
160 | (goto-char (point-min)) | |
161 | (setq save-place-alist | |
162 | (car (read-from-string | |
163 | (buffer-substring (point-min) (point-max))))) | |
6cf02570 RS |
164 | |
165 | ;; If there is a limit, and we're over it, then we'll | |
166 | ;; have to truncate the end of the list: | |
167 | (if save-place-limit | |
168 | (if (<= save-place-limit 0) | |
169 | ;; Zero gets special cased. I'm not thrilled | |
170 | ;; with this, but the loop for >= 1 is tight. | |
171 | (setq save-place-alist nil) | |
172 | ;; Else the limit is >= 1, so enforce it by | |
173 | ;; counting and then `setcdr'ing. | |
174 | (let ((s save-place-alist) | |
175 | (count 1)) | |
176 | (while s | |
177 | (if (>= count save-place-limit) | |
178 | (setcdr s nil) | |
179 | (setq count (1+ count))) | |
180 | (setq s (cdr s)))))) | |
181 | ||
722074ef | 182 | (kill-buffer (current-buffer)) |
b483a3c1 | 183 | (message "Loading places from %s...done" file) |
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184 | t) |
185 | t) | |
186 | nil)))) | |
187 | ||
188 | (defun save-places-to-alist () | |
189 | ;; go through buffer-list, saving places to alist if save-place is | |
190 | ;; non-nil, deleting them from alist if it is nil. | |
191 | (let ((buf-list (buffer-list))) | |
192 | (while buf-list | |
193 | ;; put this into a save-excursion in case someone is counting on | |
194 | ;; another function in kill-emacs-hook to act on the last buffer | |
195 | ;; they were in: | |
196 | (save-excursion | |
197 | (set-buffer (car buf-list)) | |
198 | ;; save-place checks buffer-file-name too, but we can avoid | |
199 | ;; overhead of function call by checking here too. | |
200 | (and buffer-file-name (save-place-to-alist)) | |
201 | (setq buf-list (cdr buf-list)))))) | |
b6ace927 RS |
202 | |
203 | (defun save-place-find-file-hook () | |
204 | (or save-place-loaded (load-save-place-alist-from-file)) | |
205 | (let ((cell (assoc buffer-file-name save-place-alist))) | |
206 | (if cell | |
207 | (progn | |
47c5a471 RS |
208 | (or after-find-file-from-revert-buffer |
209 | (goto-char (cdr cell))) | |
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210 | ;; and make sure it will be saved again for later |
211 | (setq save-place t))))) | |
212 | ||
4d2c9a10 | 213 | (defun save-place-kill-emacs-hook () |
b6ace927 RS |
214 | (save-places-to-alist) |
215 | (save-place-alist-to-file)) | |
216 | ||
217 | (add-hook 'find-file-hooks 'save-place-find-file-hook t) | |
218 | ||
219 | (add-hook 'kill-emacs-hook 'save-place-kill-emacs-hook) | |
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220 | |
221 | (add-hook 'kill-buffer-hook 'save-place-to-alist) | |
222 | ||
223 | (provide 'saveplace) ; why not... | |
224 | ||
225 | ;;; saveplace.el ends here | |
b6ace927 | 226 |