-;;; savehist.el --- Save minibuffer history
+;;; savehist.el --- Save minibuffer history.
-;; Copyright (c) 1997 Free Software Foundation
+;; Copyright (C) 1997, 2005, 2006 Free Software Foundation
;; Author: Hrvoje Niksic <hniksic@xemacs.org>
;; Keywords: minibuffer
-;; Version: 0.4
+;; Version: 24
;; This file is part of GNU Emacs.
;;; Commentary:
-;; This package provides the feature of saving minibuffer
-;; history to an external file after exit. When Emacs is about the exit,
-;; `savehist-save' will dump the contents of various minibuffer
-;; histories (as determined by `savehist-history-variables') to a save
-;; file (`~/.emacs-history' by default). Although the package was
-;; designed for saving the minibuffer histories, any variables can be
-;; saved that way.
+;; Many editors (e.g. Vim) have the feature of saving minibuffer
+;; history to an external file after exit. This package provides the
+;; same feature in Emacs. When set up, it saves recorded minibuffer
+;; histories to a file (`~/.emacs-history' by default). Additional
+;; variables may be specified by customizing
+;; `savehist-additional-variables'.
-;; To use savehist, put the following to `~/.emacs':
+;; To use savehist, turn on savehist-mode by putting the following in
+;; `~/.emacs':
;;
-;; (require 'savehist)
-;; (savehist-load)
+;; (savehist-mode 1)
+;;
+;; or with customize: `M-x customize-option RET savehist-mode RET'.
+;;
+;; You can also explicitly save history with `M-x savehist-save' and
+;; load it by loading the `savehist-file' with `M-x load-file'.
+
+;; If you are using a version of Emacs that does not ship with this
+;; package, be sure to have `savehist.el' in a directory that is in
+;; your load-path, and to byte-compile it.
-;; Be sure to have `savehist.el' in a directory that is in your
-;; load-path, and byte-compile it.
-\f
;;; Code:
+(require 'custom)
+(eval-when-compile
+ (require 'cl))
+
;; User variables
(defgroup savehist nil
"Save minibuffer history."
+ :version "22.1"
:group 'minibuffer)
+;;;###autoload
+(defcustom savehist-mode nil
+ "Mode for automatic saving of minibuffer history.
+Set this by calling the `savehist-mode' function or using the customize
+interface."
+ :type 'boolean
+ :set (lambda (symbol value) (savehist-mode (or value 0)))
+ :initialize 'custom-initialize-default
+ :require 'savehist
+ :group 'savehist)
-(defcustom savehist-history-variables
- '(
- ;; Catch-all minibuffer history
- minibuffer-history
- ;; File-oriented commands
- file-name-history
- ;; Regexp-related reads
- regexp-history
- ;; Searches in minibuffer (via `M-r' and such)
- minibuffer-history-search-history
- ;; Query replace
- query-replace-history
- ;; eval-expression (`M-:')
- read-expression-history
- ;; shell-command (`M-!')
- shell-command-history
- ;; compile
- compile-history
- ;; find-tag (`M-.')
- find-tag-history
- ;; grep
- grep-history
- ;; Viper stuff
- vip-ex-history vip-search-history
- vip-replace1-history vip-replace2-history
- vip-shell-history vip-search-history
-
- ;; XEmacs-specific:
- ;; Buffer-related commands
- buffer-history
- ;; Reads of variables and functions
- variable-history function-history
- ;; Extended commands
- read-command-history
-
- ;; Info, lookup, and bookmark historys
- Info-minibuffer-history
- Manual-page-minibuffer-history
-
- ;; Emacs-specific:
- ;; Extended commands
- extended-command-history)
- "*List of symbols to be saved.
-Every symbol should refer to a variable. The variable will be saved
-only if it is bound and has a non-nil value. Thus it is safe to
-specify a superset of the variables a user is expected to want to
-save.
-
-Default value contains minibuffer history variables used by Emacs, XEmacs,
-and Viper (uh-oh)."
- :type '(repeat (symbol :tag "Variable"))
+(defcustom savehist-save-minibuffer-history t
+ "*If non-nil, save all recorded minibuffer histories.
+If you want to save only specific histories, use `savehist-save-hook' to
+modify the value of `savehist-minibuffer-history-variables'."
+ :type 'boolean
:group 'savehist)
-(defcustom savehist-file "~/.emacs-history"
- "*File name to save minibuffer history to.
-The minibuffer history is a series of Lisp expressions, which should be
-loaded using `savehist-load' from your .emacs. See `savehist-load' for
-more details."
- :type 'file
+(defcustom savehist-additional-variables ()
+ "*List of additional variables to save.
+Each element is a symbol whose value will be persisted across Emacs
+sessions that use savehist. The contents of variables should be
+printable with the Lisp printer. You don't need to add minibuffer
+history variables to this list, all minibuffer histories will be
+saved automatically as long as `savehist-save-minibuffer-history' is
+non-nil.
+
+User options should be saved with the customize interface. This
+list is useful for saving automatically updated variables that are not
+minibuffer histories, such as `compile-command' or `kill-ring'."
+ :type '(repeat variable)
+ :group 'savehist)
+
+(defcustom savehist-ignored-variables nil ;; '(command-history)
+ "*List of additional variables not to save."
+ :type '(repeat variable)
:group 'savehist)
-(defcustom savehist-length 100
- "*Maximum length of a minibuffer list.
-If set to nil, the length is unlimited."
- :type '(choice integer
- (const :tag "Unlimited" nil))
+(defcustom savehist-file
+ (cond
+ ;; Backward compatibility with previous versions of savehist.
+ ((file-exists-p "~/.emacs-history") "~/.emacs-history")
+ ((and (not (featurep 'xemacs)) (file-directory-p "~/.emacs.d/"))
+ "~/.emacs.d/history")
+ ((and (featurep 'xemacs) (file-directory-p "~/.xemacs/"))
+ "~/.xemacs/history")
+ ;; For users without `~/.emacs.d/' or `~/.xemacs/'.
+ (t "~/.emacs-history"))
+ "*File name where minibuffer history is saved to and loaded from.
+The minibuffer history is a series of Lisp expressions loaded
+automatically when `savehist-mode' is turned on. See `savehist-mode'
+for more details.
+
+If you want your minibuffer history shared between Emacs and XEmacs,
+customize this value and make sure that `savehist-coding-system' is
+set to a coding system that exists in both emacsen."
+ :type 'file
:group 'savehist)
-(defcustom savehist-modes 384
+(defcustom savehist-file-modes #o600
"*Default permissions of the history file.
-This is decimal, not octal. The default is 384 (0600 in octal)."
+This is decimal, not octal. The default is 384 (0600 in octal).
+Set to nil to use the default permissions that Emacs uses, typically
+mandated by umask. The default is a bit more restrictive to protect
+the user's privacy."
+ :type 'integer
+ :group 'savehist)
+
+(defcustom savehist-autosave-interval (* 5 60)
+ "*The interval between autosaves of minibuffer history.
+If set to nil, disables timer-based autosaving."
:type 'integer
:group 'savehist)
+(defcustom savehist-mode-hook nil
+ "Hook called when `savehist-mode' is turned on."
+ :type 'hook
+ :group 'savehist)
+
+(defcustom savehist-save-hook nil
+ "Hook called by `savehist-save' before saving the variables.
+You can use this hook to influence choice and content of variables to
+save."
+ :type 'hook
+ :group 'savehist)
+
+;; This should be capable of representing characters used by Emacs.
+;; We prefer UTF-8 over ISO 2022 because it is well-known outside
+;; Mule. XEmacs prir to 21.5 had UTF-8 provided by an external
+;; package which may not be loaded, which is why we check for version.
+(defvar savehist-coding-system (if (and (featurep 'xemacs)
+ (<= emacs-major-version 21)
+ (< emacs-minor-version 5))
+ 'iso-2022-8 'utf-8)
+ "The coding system savehist uses for saving the minibuffer history.
+Changing this value while Emacs is running is supported, but considered
+unwise, unless you know what you are doing.")
+
+;; Internal variables.
+
+(defvar savehist-timer nil)
+
+(defvar savehist-last-checksum nil)
+
+(defvar savehist-minibuffer-history-variables nil
+ "List of minibuffer histories.
+The contents of this variable is built while Emacs is running, and saved
+along with minibuffer history. You can change its value off
+`savehist-save-hook' to influence which variables are saved.")
+
+(defconst savehist-no-conversion (if (featurep 'xemacs) 'binary 'no-conversion)
+ "Coding system without any conversion.
+This is used for calculating an internal checksum. Should be as fast
+as possible, ideally simply exposing the internal representation of
+buffer text.")
+
+(defvar savehist-loaded nil
+ "Whether the history has already been loaded.
+This prevents toggling `savehist-mode' from destroying existing
+minibuffer history.")
+
+(when (featurep 'xemacs)
+ ;; Must declare this under XEmacs, which doesn't have built-in
+ ;; minibuffer history truncation.
+ (defvar history-length 100))
\f
-;; Functions
+;; Functions.
;;;###autoload
-(defun savehist-load (&optional no-hook)
- "Load the minibuffer histories from `savehist-file'.
-Unless NO-HOOK is specified, the function will also add the save function
-to `kill-emacs-hook', thus ensuring that the minibuffer contents will be
-saved before leaving Emacs.
-
-This function should be normally used from your Emacs init file. Since it
-removes your current minibuffer histories, it is unwise to call it at any
-other time."
+(defun savehist-mode (arg)
+ "Toggle savehist-mode.
+Positive ARG turns on `savehist-mode'. When on, savehist-mode causes
+minibuffer history to be saved periodically and when exiting Emacs.
+When turned on for the first time in an Emacs session, it causes the
+previous minibuffer history to be loaded from `savehist-file'.
+
+This mode should normally be turned on from your Emacs init file.
+Calling it at any other time replaces your current minibuffer histories,
+which is probably undesirable."
(interactive "P")
- (unless no-hook
- (add-hook 'kill-emacs-hook 'savehist-save))
- (load savehist-file t))
+ (setq savehist-mode
+ (if (null arg)
+ (not savehist-mode)
+ (> (prefix-numeric-value arg) 0)))
+ (if (not savehist-mode)
+ (savehist-uninstall)
+ (when (and (not savehist-loaded)
+ (file-exists-p savehist-file))
+ (condition-case errvar
+ (progn
+ ;; Don't set coding-system-for-read -- we rely on the
+ ;; coding cookie to convey that information. That way, if
+ ;; the user changes the value of savehist-coding-system,
+ ;; we can still correctly load the old file.
+ (load savehist-file nil (not (interactive-p)))
+ (setq savehist-loaded t))
+ (error
+ ;; Don't install the mode if reading failed. Doing so would
+ ;; effectively destroy the user's data at the next save.
+ (setq savehist-mode nil)
+ (savehist-uninstall)
+ (signal (car errvar) (cdr errvar)))))
+ (savehist-install)
+ (run-hooks 'savehist-mode-hook))
+ ;; Return the new setting.
+ savehist-mode)
+(add-minor-mode 'savehist-mode "")
-;;;###autoload
-(defun savehist-save ()
- "Save the histories from `savehist-history-variables' to `savehist-file'.
-A variable will be saved if it is bound and non-nil."
+(defun savehist-load ()
+ "Obsolete function provided for transition from old versions of savehist.
+Don't call this from new code, use (savehist-mode 1) instead.
+
+This function loads the variables stored in `savehist-file' and turns on
+`savehist-mode'. If `savehist-file' is in the old format that doesn't
+record the value of `savehist-minibuffer-history-variables', that value
+is deducted from the contents of the file."
+ (savehist-mode 1)
+ ;; Old versions of savehist distributed with XEmacs didn't save
+ ;; savehist-minibuffer-history-variables. If that variable is nil
+ ;; after loading the file, try to intuit the intended value.
+ (when (null savehist-minibuffer-history-variables)
+ (setq savehist-minibuffer-history-variables
+ (with-temp-buffer
+ (ignore-errors
+ (insert-file-contents savehist-file))
+ (let ((vars ()) form)
+ (while (setq form (condition-case nil
+ (read (current-buffer)) (error nil)))
+ ;; Each form read is of the form (setq VAR VALUE).
+ ;; Collect VAR, i.e. (nth form 1).
+ (push (nth 1 form) vars))
+ vars)))))
+(make-obsolete 'savehist-load 'savehist-mode)
+
+(defun savehist-install ()
+ "Hook savehist into Emacs.
+Normally invoked by calling `savehist-mode' to set the minor mode.
+Installs `savehist-autosave' in `kill-emacs-hook' and on a timer.
+To undo this, call `savehist-uninstall'."
+ (add-hook 'minibuffer-setup-hook 'savehist-minibuffer-hook)
+ (add-hook 'kill-emacs-hook 'savehist-autosave)
+ ;; Install an invocation of savehist-autosave on a timer. This
+ ;; should not cause noticeable delays for users -- savehist-autosave
+ ;; executes in under 5 ms on my system.
+ (when (and savehist-autosave-interval
+ (null savehist-timer))
+ (setq savehist-timer
+ (if (featurep 'xemacs)
+ (start-itimer
+ "savehist" 'savehist-autosave savehist-autosave-interval
+ savehist-autosave-interval)
+ (run-with-timer savehist-autosave-interval
+ savehist-autosave-interval 'savehist-autosave)))))
+
+(defun savehist-uninstall ()
+ "Undo installing savehist.
+Normally invoked by calling `savehist-mode' to unset the minor mode."
+ (remove-hook 'minibuffer-setup-hook 'savehist-minibuffer-hook)
+ (remove-hook 'kill-emacs-hook 'savehist-autosave)
+ (when savehist-timer
+ (if (featurep 'xemacs)
+ (delete-itimer savehist-timer)
+ (cancel-timer savehist-timer))
+ (setq savehist-timer nil)))
+
+(defun savehist-save (&optional auto-save)
+ "Save the values of minibuffer history variables.
+Unbound symbols referenced in `savehist-additional-variables' are ignored.
+If AUTO-SAVE is non-nil, compare the saved contents to the one last saved,
+ and don't save the buffer if they are the same."
(interactive)
- (save-excursion
- ;; Is it wise to junk `find-file-hooks' just like that? How else
- ;; should I avoid font-lock et al.?
- (let ((find-file-hooks nil)
- (buffer-exists-p (get-file-buffer savehist-file)))
- (set-buffer (find-file-noselect savehist-file))
- (unwind-protect
- (progn
- (erase-buffer)
- (insert
- ";; -*- emacs-lisp -*-\n"
- ";; Minibuffer history file.\n\n"
- ";; This file is automatically generated by `savehist-save'"
- " or when\n"
- ";; exiting Emacs.\n"
- ";; Do not edit. Unless you really want to, that is.\n\n")
- (let ((print-length nil)
- (print-string-length nil)
- (print-level nil)
- (print-readably t))
- (dolist (sym savehist-history-variables)
- (when (and (boundp sym)
- (symbol-value sym))
- (prin1
- `(setq ,sym (quote ,(savehist-delimit (symbol-value sym)
- savehist-length)))
- (current-buffer))
- (insert ?\n))))
- (save-buffer)
- (set-file-modes savehist-file savehist-modes))
- (or buffer-exists-p
- (kill-buffer (current-buffer)))))))
-
-;; If ARG is a list with less than N elements, return it, else return
-;; its subsequence of N elements. If N is nil or ARG is not a list,
-;; always return ARG.
-(defun savehist-delimit (arg n)
- (if (and n
- (listp arg)
- (> (length arg) n))
- (subseq arg 0 n)
- arg))
+ (with-temp-buffer
+ (insert
+ (format ";; -*- mode: emacs-lisp; coding: %s -*-\n" savehist-coding-system)
+ ";; Minibuffer history file, automatically generated by `savehist'.\n\n")
+ (run-hooks 'savehist-save-hook)
+ (let ((print-length nil)
+ (print-string-length nil)
+ (print-level nil)
+ (print-readably t)
+ (print-quoted t))
+ ;; Save the minibuffer histories, along with the value of
+ ;; savehist-minibuffer-history-variables itself.
+ (when savehist-save-minibuffer-history
+ (prin1 `(setq savehist-minibuffer-history-variables
+ ',savehist-minibuffer-history-variables)
+ (current-buffer))
+ (insert ?\n)
+ (dolist (symbol savehist-minibuffer-history-variables)
+ (when (boundp symbol)
+ (let ((value (savehist-trim-history (symbol-value symbol))))
+ (when value ; don't save empty histories
+ (prin1 `(setq ,symbol ',value) (current-buffer))
+ (insert ?\n))))))
+ ;; Save the additional variables.
+ (dolist (symbol savehist-additional-variables)
+ (when (boundp symbol)
+ (let ((value (symbol-value symbol)))
+ (when (savehist-printable value)
+ (prin1 `(setq ,symbol ',value) (current-buffer))
+ (insert ?\n))))))
+ ;; If autosaving, avoid writing if nothing has changed since the
+ ;; last write.
+ (let ((checksum (md5 (current-buffer) nil nil savehist-no-conversion)))
+ (unless (and auto-save (equal checksum savehist-last-checksum))
+ ;; Set file-precious-flag when saving the buffer because we
+ ;; don't want a half-finished write ruining the entire
+ ;; history. Remember that this is run from a timer and from
+ ;; kill-emacs-hook, and also that multiple Emacs instances
+ ;; could write to this file at once.
+ (let ((file-precious-flag t)
+ (coding-system-for-write savehist-coding-system))
+ (write-region (point-min) (point-max) savehist-file nil
+ (unless (interactive-p) 'quiet)))
+ (when savehist-file-modes
+ (set-file-modes savehist-file savehist-file-modes))
+ (setq savehist-last-checksum checksum)))))
+
+(defun savehist-autosave ()
+ "Save the minibuffer history if it has been modified since the last save.
+Does nothing if `savehist-mode' is off."
+ (when savehist-mode
+ (savehist-save t)))
+
+(defun savehist-trim-history (value)
+ "Retain only the first `history-length' items in VALUE.
+Only used under XEmacs, which doesn't (yet) implement automatic
+trimming of history lists to `history-length' items."
+ (if (and (featurep 'xemacs)
+ (natnump history-length)
+ (> (length value) history-length))
+ ;; Equivalent to `(subseq value 0 history-length)', but doesn't
+ ;; need cl-extra at run-time.
+ (loop repeat history-length collect (pop value))
+ value))
+
+(defun savehist-printable (value)
+ "Return non-nil if VALUE is printable."
+ (cond
+ ;; Quick response for oft-encountered types known to be printable.
+ ((stringp value))
+ ((numberp value))
+ ((symbolp value))
+ (t
+ ;; For others, check explicitly.
+ (with-temp-buffer
+ (condition-case nil
+ (let ((print-readably t) (print-level nil))
+ ;; Print the value into a buffer...
+ (prin1 value (current-buffer))
+ ;; ...and attempt to read it.
+ (read (point-min-marker))
+ ;; The attempt worked: the object is printable.
+ t)
+ ;; The attempt failed: the object is not printable.
+ (error nil))))))
+
+(defun savehist-minibuffer-hook ()
+ (unless (or (eq minibuffer-history-variable t)
+ ;; XEmacs sets minibuffer-history-variable to t to mean "no
+ ;; history is being recorded".
+ (memq minibuffer-history-variable savehist-ignored-variables))
+ (add-to-list 'savehist-minibuffer-history-variables
+ minibuffer-history-variable)))
(provide 'savehist)
+\f
+;; arch-tag: b3ce47f4-c5ad-4ebc-ad02-73aba705cf9f
;;; savehist.el ends here