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2b86d62c | 1 | ;;; loadhist.el --- lisp functions for working with feature groups |
131a0c01 | 2 | ;;; Copyright (C) 1995 Free Software Foundation, Inc. |
2b86d62c RS |
3 | |
4 | ;; Author: Eric S. Raymond <esr@snark.thyrsus.com> | |
5 | ;; Version: 1.0 | |
6 | ;; Keywords: internal | |
7 | ||
131a0c01 KH |
8 | ;; This file is part of GNU Emacs. |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
11 | ;; it under the terms of the GNU General Public License as published by | |
12 | ;; the Free Software Foundation; either version 2, or (at your option) | |
13 | ;; any later version. | |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to | |
22 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | ||
2b86d62c RS |
24 | ;;; Commentary: |
25 | ||
26 | ;; These functions exploit the load-history system variable. | |
27 | ;; Entry points include `unload-feature', `symbol-file', and `feature-file'. | |
28 | ||
29 | ;;; Code: | |
30 | ||
31 | (defun symbol-file (sym) | |
32 | "Return the input source from which SYM was loaded. | |
33 | This is a file name, or nil if the source was a buffer with no associated file." | |
34 | (catch 'foundit | |
35 | (mapcar | |
36 | (function (lambda (x) (if (memq sym (cdr x)) (throw 'foundit (car x))))) | |
37 | load-history) | |
38 | nil)) | |
39 | ||
40 | (defun feature-symbols (feature) | |
41 | "Return the file and list of symbols associated with a given FEATURE." | |
42 | (catch 'foundit | |
43 | (mapcar | |
44 | (function (lambda (x) | |
45 | (if (member (cons 'provide feature) (cdr x)) | |
46 | (throw 'foundit x)))) | |
47 | load-history) | |
48 | nil)) | |
49 | ||
50 | (defun feature-file (feature) | |
51 | "Return the file name from which a given FEATURE was loaded. | |
52 | Actually, return the load argument, if any; this is sometimes the name of a | |
53 | Lisp file without an extension. If the feature came from an eval-buffer on | |
54 | a buffer with no associated file, or an eval-region, return nil." | |
55 | (if (not (featurep feature)) | |
56 | (error "%s is not a currently loaded feature." (symbol-name feature)) | |
57 | (car (feature-symbols feature)))) | |
58 | ||
59 | (defun file-provides (file) | |
60 | "Return the list of features provided by FILE." | |
61 | (let ((symbols (cdr (assoc file load-history))) (provides nil)) | |
62 | (mapcar | |
63 | (function (lambda (x) | |
64 | (if (and (consp x) (eq (car x) 'provide)) | |
65 | (setq provides (cons (cdr x) provides))))) | |
66 | symbols) | |
67 | provides | |
68 | )) | |
69 | ||
70 | (defun file-requires (file) | |
71 | "Return the list of features required by FILE." | |
72 | (let ((symbols (cdr (assoc file load-history))) (requires nil)) | |
73 | (mapcar | |
74 | (function (lambda (x) | |
75 | (if (and (consp x) (eq (car x) 'require)) | |
76 | (setq requires (cons (cdr x) requires))))) | |
77 | symbols) | |
78 | requires | |
79 | )) | |
80 | ||
81 | (defun set-intersect (p q) | |
82 | ;; Return the set intersection of two lists | |
83 | (let ((ret nil)) | |
84 | (mapcar | |
85 | (function (lambda (x) (if (memq x q) (setq ret (cons x ret))))) | |
86 | p) | |
87 | ret | |
88 | )) | |
89 | ||
90 | (defun file-dependents (file) | |
e01ac82c RS |
91 | "Return the list of loaded libraries that depend on FILE. |
92 | This can include FILE itself." | |
2b86d62c RS |
93 | (let ((provides (file-provides file)) (dependents nil)) |
94 | (mapcar | |
95 | (function (lambda (x) | |
96 | (if (set-intersect provides (file-requires (car x))) | |
97 | (setq dependents (cons (car x) dependents))))) | |
98 | load-history) | |
99 | dependents | |
100 | )) | |
101 | ||
102 | ;;;###autoload | |
103 | (defun unload-feature (feature &optional force) | |
104 | "Unload the library that provided FEATURE, restoring all its autoloads. | |
105 | If the feature is required by any other loaded code, and optional FORCE | |
106 | is nil, raise an error." | |
107 | (interactive "SFeature: ") | |
108 | (if (not (featurep feature)) | |
109 | (error "%s is not a currently loaded feature." (symbol-name feature))) | |
110 | (if (not force) | |
e01ac82c RS |
111 | (let* ((file (feature-file feature)) |
112 | (dependents (delete file (copy-sequence (file-dependents file))))) | |
2b86d62c RS |
113 | (if dependents |
114 | (error "Loaded libraries %s depend on %s." | |
115 | (prin1-to-string dependents) file) | |
116 | ))) | |
117 | (let* ((flist (feature-symbols feature)) (file (car flist))) | |
118 | (mapcar | |
119 | (function (lambda (x) | |
120 | (cond ((stringp x) nil) | |
c344d4be KH |
121 | ((consp x) |
122 | ;; Remove any feature names that this file provided. | |
123 | (if (eq (car x) 'provide) | |
124 | (setq features (delq (cdr x) features)))) | |
2b86d62c RS |
125 | ((boundp x) (makunbound x)) |
126 | ((fboundp x) | |
127 | (fmakunbound x) | |
128 | (let ((aload (get x 'autoload))) | |
96c3ed60 | 129 | (if aload (fset x (cons 'autoload aload))))))) |
2b86d62c RS |
130 | ) |
131 | (cdr flist)))) | |
132 | ||
133 | (provide 'loadhist) | |
134 | ||
135 | ;;; loadhist.el ends here |