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a2535589 JA |
1 | ;; Copyright (C) 1985, 1986 Free Software Foundation, inc. |
2 | ||
3 | ;; This file is part of GNU Emacs. | |
4 | ||
5 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
6 | ;; it under the terms of the GNU General Public License as published by | |
7 | ;; the Free Software Foundation; either version 1, or (at your option) | |
8 | ;; any later version. | |
9 | ||
10 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
11 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | ;; GNU General Public License for more details. | |
14 | ||
15 | ;; You should have received a copy of the GNU General Public License | |
16 | ;; along with GNU Emacs; see the file COPYING. If not, write to | |
17 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
18 | ||
19 | ||
20 | ;; This file is autloaded to handle certain conditions | |
21 | ;; detected by the file-locking code within Emacs. | |
22 | ;; The two entry points are `ask-user-about-lock' and | |
23 | ;; `ask-user-about-supersession-threat'. | |
24 | ||
25 | ||
26 | (put 'file-locked 'error-conditions '(file-locked file-error error)) | |
27 | ||
f9f9507e | 28 | ;;;###autoload |
a2535589 JA |
29 | (defun ask-user-about-lock (fn opponent) |
30 | "Ask user what to do when he wants to edit FILE but it is locked by USER. | |
31 | This function has a choice of three things to do: | |
32 | do (signal 'buffer-file-locked (list FILE USER)) | |
33 | to refrain from editing the file | |
34 | return t (grab the lock on the file) | |
35 | return nil (edit the file even though it is locked). | |
36 | You can rewrite it to use any criterion you like to choose which one to do." | |
37 | (discard-input) | |
38 | (save-window-excursion | |
39 | (let (answer) | |
40 | (while (null answer) | |
41 | (message "%s is locking %s: action (s, q, p, ?)? " opponent fn) | |
42 | (let ((tem (let ((inhibit-quit t) | |
43 | (cursor-in-echo-area t)) | |
44 | (prog1 (downcase (read-char)) | |
45 | (setq quit-flag nil))))) | |
46 | (if (= tem help-char) | |
47 | (ask-user-about-lock-help) | |
48 | (setq answer (assoc tem '((?s . t) | |
49 | (?q . yield) | |
50 | (?\C-g . yield) | |
51 | (?p . nil) | |
52 | (?? . help)))) | |
53 | (cond ((null answer) | |
54 | (beep) | |
55 | (message "Please type q, s, or p; or ? for help") | |
56 | (sit-for 3)) | |
57 | ((eq (cdr answer) 'help) | |
58 | (ask-user-about-lock-help) | |
59 | (setq answer nil)) | |
60 | ((eq (cdr answer) 'yield) | |
61 | (signal 'file-locked (list "File is locked" fn opponent))))))) | |
62 | (cdr answer)))) | |
63 | ||
64 | (defun ask-user-about-lock-help () | |
65 | (with-output-to-temp-buffer "*Help*" | |
66 | (princ "It has been detected that you want to modify a file that someone else has | |
67 | already started modifying in EMACS. | |
68 | ||
69 | You can <s>teal the file; The other user becomes the | |
70 | intruder if (s)he ever unmodifies the file and then changes it again. | |
71 | You can <p>roceed; you edit at your own (and the other user's) risk. | |
72 | You can <q>uit; don't modify this file."))) | |
73 | ||
74 | (put | |
75 | 'file-supersession 'error-conditions '(file-supersession file-error error)) | |
76 | ||
f9f9507e | 77 | ;;;###autoload |
a2535589 JA |
78 | (defun ask-user-about-supersession-threat (fn) |
79 | "Ask a user who is about to modify an obsolete buffer what to do. | |
80 | This function has two choices: it can return, in which case the modification | |
81 | of the buffer will proceed, or it can (signal 'file-supersession (file)), | |
82 | in which case the proposed buffer modification will not be made. | |
83 | ||
84 | You can rewrite this to use any criterion you like to choose which one to do. | |
85 | The buffer in question is current when this function is called." | |
86 | (discard-input) | |
87 | (save-window-excursion | |
88 | (let (answer) | |
89 | (while (null answer) | |
90 | (message "File has changed on disk; really want to edit the buffer? (y, n or C-h) ") | |
91 | (let ((tem (downcase (let ((cursor-in-echo-area t)) | |
92 | (read-char))))) | |
93 | (setq answer | |
94 | (if (= tem help-char) | |
95 | 'help | |
96 | (cdr (assoc tem '((?n . yield) | |
97 | (?\C-g . yield) | |
98 | (?y . proceed) | |
99 | (?? . help)))))) | |
100 | (cond ((null answer) | |
101 | (beep) | |
102 | (message "Please type y or n; or ? for help") | |
103 | (sit-for 3)) | |
104 | ((eq answer 'help) | |
105 | (ask-user-about-supersession-help) | |
106 | (setq answer nil)) | |
107 | ((eq answer 'yield) | |
108 | (signal 'file-supersession | |
109 | (list "File changed on disk" fn)))))) | |
110 | (message | |
111 | "File on disk now will become a backup file if you save these changes.") | |
112 | (setq buffer-backed-up nil)))) | |
113 | ||
114 | (defun ask-user-about-supersession-help () | |
115 | (with-output-to-temp-buffer "*Help*" | |
116 | (princ "You want to modify a buffer whose disk file has changed | |
117 | since you last read it in or saved it with this buffer. | |
118 | ||
119 | If you say `y' to go ahead and modify this buffer, | |
120 | you risk ruining the work of whoever rewrote the file. | |
121 | If you say `n', the change you started to make will be aborted. | |
122 | ||
123 | Usually, you should type `n' and then `M-x revert-buffer', | |
124 | to get the latest version of the file, then make the change again."))) | |
125 | ||
126 |