1;;; loadhist.el --- lisp functions for working with feature groups 2 3;; Copyright (C) 1995, 1998, 2000, 2001, 2002, 2003, 2004, 4;; 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Author: Eric S. Raymond <esr@snark.thyrsus.com> 7;; Maintainer: FSF 8;; Keywords: internal 9 10;; This file is part of GNU Emacs. 11 12;; GNU Emacs is free software; you can redistribute it and/or modify 13;; it under the terms of the GNU General Public License as published by 14;; the Free Software Foundation; either version 2, or (at your option) 15;; any later version. 16 17;; GNU Emacs is distributed in the hope that it will be useful, 18;; but WITHOUT ANY WARRANTY; without even the implied warranty of 19;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20;; GNU General Public License for more details. 21 22;; You should have received a copy of the GNU General Public License 23;; along with GNU Emacs; see the file COPYING. If not, write to the 24;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 25;; Boston, MA 02110-1301, USA. 26 27;;; Commentary: 28 29;; These functions exploit the load-history system variable. 30;; Entry points include `unload-feature', `symbol-file', and 31;; `feature-file', documented in the Emacs Lisp manual. 32 33;;; Code: 34 35(eval-when-compile (require 'cl)) 36 37(defun feature-symbols (feature) 38 "Return the file and list of definitions associated with FEATURE. 39The value is actually the element of `load-history' 40for the file that did (provide FEATURE)." 41 (catch 'foundit 42 (mapc (lambda (x) 43 (if (member (cons 'provide feature) (cdr x)) 44 (throw 'foundit x))) 45 load-history) 46 nil)) 47 48(defun feature-file (feature) 49 "Return the file name from which a given FEATURE was loaded. 50Actually, return the load argument, if any; this is sometimes the name of a 51Lisp file without an extension. If the feature came from an `eval-buffer' on 52a buffer with no associated file, or an `eval-region', return nil." 53 (if (not (featurep feature)) 54 (error "%S is not a currently loaded feature" feature) 55 (car (feature-symbols feature)))) 56 57(defun file-loadhist-lookup (file) 58 "Return the `load-history' element for FILE. 59FILE can be a file name, or a library name. 60A library name is equivalent to the file name that `load-library' would load." 61 ;; First look for FILE as given. 62 (let ((symbols (assoc file load-history))) 63 ;; Try converting a library name to an absolute file name. 64 (and (null symbols) 65 (let ((absname 66 (locate-file file load-path (get-load-suffixes)))) 67 (and absname (not (equal absname file)) 68 (setq symbols (cdr (assoc absname load-history)))))) 69 symbols)) 70 71(defun file-provides (file) 72 "Return the list of features provided by FILE as it was loaded. 73FILE can be a file name, or a library name. 74A library name is equivalent to the file name that `load-library' would load." 75 (let ((symbols (file-loadhist-lookup file)) 76 provides) 77 (mapc (lambda (x) 78 (if (and (consp x) (eq (car x) 'provide)) 79 (setq provides (cons (cdr x) provides)))) 80 symbols) 81 provides)) 82 83(defun file-requires (file) 84 "Return the list of features required by FILE as it was loaded. 85FILE can be a file name, or a library name. 86A library name is equivalent to the file name that `load-library' would load." 87 (let ((symbols (file-loadhist-lookup file)) 88 requires) 89 (mapc (lambda (x) 90 (if (and (consp x) (eq (car x) 'require)) 91 (setq requires (cons (cdr x) requires)))) 92 symbols) 93 requires)) 94 95(defsubst file-set-intersect (p q) 96 "Return the set intersection of two lists." 97 (let ((ret nil)) 98 (dolist (x p ret) 99 (if (memq x q) (setq ret (cons x ret)))) 100 ret)) 101 102(defun file-dependents (file) 103 "Return the list of loaded libraries that depend on FILE. 104This can include FILE itself. 105FILE can be a file name, or a library name. 106A library name is equivalent to the file name that `load-library' would load." 107 (let ((provides (file-provides file)) 108 (dependents nil)) 109 (dolist (x load-history dependents) 110 (if (file-set-intersect provides (file-requires (car x))) 111 (setq dependents (cons (car x) dependents)))) 112 dependents)) 113 114(defun read-feature (prompt &optional loaded-p) 115 "Read feature name from the minibuffer, prompting with string PROMPT. 116If optional second arg LOADED-P is non-nil, the feature must be loaded 117from a file." 118 (intern 119 (completing-read prompt 120 (cons nil features) 121 (and loaded-p 122 #'(lambda (f) 123 (and f ; ignore nil 124 (feature-file f)))) 125 loaded-p))) 126 127(defvaralias 'loadhist-hook-functions 'unload-feature-special-hooks) 128(defvar unload-feature-special-hooks 129 '(after-change-functions 130 after-insert-file-functions auto-fill-function 131 before-change-functions blink-paren-function 132 buffer-access-fontify-functions command-line-functions 133 comment-indent-function kill-buffer-query-functions 134 kill-emacs-query-functions lisp-indent-function 135 mouse-position-function 136 redisplay-end-trigger-functions temp-buffer-show-function 137 window-scroll-functions window-size-change-functions 138 write-region-annotate-functions) 139 "A list of special hooks from Info node `(elisp)Standard Hooks'. 140 141These are symbols with hook-type values whose names don't end in 142`-hook' or `-hooks', from which `unload-feature' tries to remove 143pertinent symbols.") 144 145(defvar unload-hook-features-list nil 146 "List of features of the package being unloaded. 147 148This is meant to be used by FEATURE-unload-hook hooks, see the 149documentation of `unload-feature' for details.") 150 151;;;###autoload 152(defun unload-feature (feature &optional force) 153 "Unload the library that provided FEATURE, restoring all its autoloads. 154If the feature is required by any other loaded code, and prefix arg FORCE 155is nil, raise an error. 156 157This function tries to undo modifications made by the package to 158hooks. Packages may define a hook FEATURE-unload-hook that is called 159instead of the normal heuristics for doing this. Such a hook should 160undo all the relevant global state changes that may have been made by 161loading the package or executing functions in it. It has access to 162the package's feature list (before anything is unbound) in the 163variable `unload-hook-features-list' and could remove features from it 164in the event that the package has done something normally-ill-advised, 165such as redefining an Emacs function." 166 (interactive 167 (list 168 (read-feature "Unload feature: " t) 169 current-prefix-arg)) 170 (unless (featurep feature) 171 (error "%s is not a currently loaded feature" (symbol-name feature))) 172 (unless force 173 (let* ((file (feature-file feature)) 174 (dependents (delete file (copy-sequence (file-dependents file))))) 175 (when dependents 176 (error "Loaded libraries %s depend on %s" 177 (prin1-to-string dependents) file)))) 178 (let* ((unload-hook-features-list (feature-symbols feature)) 179 (file (pop unload-hook-features-list)) 180 ;; If non-nil, this is a symbol for which we should 181 ;; restore a previous autoload if possible. 182 restore-autoload 183 (unload-hook (intern-soft (concat (symbol-name feature) 184 "-unload-hook")))) 185 ;; Try to avoid losing badly when hooks installed in critical 186 ;; places go away. (Some packages install things on 187 ;; `kill-buffer-hook', `activate-menubar-hook' and the like.) 188 ;; First off, provide a clean way for package FOO to arrange 189 ;; this by adding hooks on the variable `FOO-unload-hook'. 190 (if unload-hook 191 (run-hooks unload-hook) 192 ;; Otherwise, do our best. Look through the obarray for symbols 193 ;; which seem to be hook variables or special hook functions and 194 ;; remove anything from them which matches the feature-symbols 195 ;; about to get zapped. Obviously this won't get anonymous 196 ;; functions which the package might just have installed, and 197 ;; there might be other important state, but this tactic 198 ;; normally works. 199 (mapatoms 200 (lambda (x) 201 (when (and (boundp x) 202 (or (and (consp (symbol-value x)) ; Random hooks. 203 (string-match "-hooks?\\'" (symbol-name x))) 204 (memq x unload-feature-special-hooks))) ; Known abnormal hooks etc. 205 (dolist (y unload-hook-features-list) 206 (when (and (eq (car-safe y) 'defun) 207 (not (get (cdr y) 'autoload))) 208 (remove-hook x (cdr y))))))) 209 ;; Remove any feature-symbols from auto-mode-alist as well. 210 (dolist (y unload-hook-features-list) 211 (when (and (eq (car-safe y) 'defun) 212 (not (get (cdr y) 'autoload))) 213 (setq auto-mode-alist 214 (rassq-delete-all (cdr y) auto-mode-alist))))) 215 (when (fboundp 'elp-restore-function) ; remove ELP stuff first 216 (dolist (elt unload-hook-features-list) 217 (when (symbolp elt) 218 (elp-restore-function elt)))) 219 220 (dolist (x unload-hook-features-list) 221 (if (consp x) 222 (case (car x) 223 ;; Remove any feature names that this file provided. 224 (provide 225 (setq features (delq (cdr x) features))) 226 ((defun autoload) 227 (let ((fun (cdr x))) 228 (when (fboundp fun) 229 (when (fboundp 'ad-unadvise) 230 (ad-unadvise fun)) 231 (let ((aload (get fun 'autoload))) 232 (if (and aload (eq fun restore-autoload)) 233 (fset fun (cons 'autoload aload)) 234 (fmakunbound fun)))))) 235 ;; (t . SYMBOL) comes before (defun . SYMBOL) 236 ;; and says we should restore SYMBOL's autoload 237 ;; when we undefine it. 238 ((t) (setq restore-autoload (cdr x))) 239 ((require defface) nil) 240 (t (message "Unexpected element %s in load-history" x))) 241 ;; Kill local values as much as possible. 242 (dolist (buf (buffer-list)) 243 (with-current-buffer buf 244 (if (and (boundp x) (timerp (symbol-value x))) 245 (cancel-timer (symbol-value x))) 246 (kill-local-variable x))) 247 (if (and (boundp x) (timerp (symbol-value x))) 248 (cancel-timer (symbol-value x))) 249 ;; Get rid of the default binding if we can. 250 (unless (local-variable-if-set-p x) 251 (makunbound x)))) 252 ;; Delete the load-history element for this file. 253 (setq load-history (delq (assoc file load-history) load-history))) 254 ;; Don't return load-history, it is not useful. 255 nil) 256 257(provide 'loadhist) 258 259;; arch-tag: 70bb846a-c413-4f01-bf88-78dba4ac0798 260;;; loadhist.el ends here 261