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410 lines
15 KiB
EmacsLisp
410 lines
15 KiB
EmacsLisp
;;; savehist.el --- Save minibuffer history
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;; Copyright (C) 1997, 2005-2013 Free Software Foundation, Inc.
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;; Author: Hrvoje Niksic <hniksic@xemacs.org>
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;; Maintainer: FSF
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;; Keywords: minibuffer
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;; Version: 24
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:
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;; Many editors (e.g. Vim) have the feature of saving minibuffer
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;; history to an external file after exit. This package provides the
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;; same feature in Emacs. When set up, it saves recorded minibuffer
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;; histories to a file (`~/.emacs-history' by default). Additional
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;; variables may be specified by customizing
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;; `savehist-additional-variables'.
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;; To use savehist, turn on savehist-mode by putting the following in
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;; `~/.emacs':
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;;
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;; (savehist-mode 1)
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;;
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;; or with customize: `M-x customize-option RET savehist-mode RET'.
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;;
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;; You can also explicitly save history with `M-x savehist-save' and
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;; load it by loading the `savehist-file' with `M-x load-file'.
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;; If you are using a version of Emacs that does not ship with this
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;; package, be sure to have `savehist.el' in a directory that is in
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;; your load-path, and to byte-compile it.
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;;; Code:
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(require 'custom)
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(eval-when-compile
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(require 'cl))
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;; User variables
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(defgroup savehist nil
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"Save minibuffer history."
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:version "22.1"
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:group 'minibuffer)
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(defcustom savehist-save-minibuffer-history t
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"If non-nil, save all recorded minibuffer histories.
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If you want to save only specific histories, use `savehist-save-hook' to
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modify the value of `savehist-minibuffer-history-variables'."
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:type 'boolean
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:group 'savehist)
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(defcustom savehist-additional-variables ()
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"List of additional variables to save.
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Each element is a symbol whose value will be persisted across Emacs
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sessions that use savehist. The contents of variables should be
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printable with the Lisp printer. You don't need to add minibuffer
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history variables to this list, all minibuffer histories will be
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saved automatically as long as `savehist-save-minibuffer-history' is
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non-nil.
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User options should be saved with the customize interface. This
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list is useful for saving automatically updated variables that are not
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minibuffer histories, such as `compile-command' or `kill-ring'."
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:type '(repeat variable)
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:group 'savehist)
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(defcustom savehist-ignored-variables nil ;; '(command-history)
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"List of additional variables not to save."
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:type '(repeat variable)
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:group 'savehist)
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(defcustom savehist-file
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(locate-user-emacs-file "history" ".emacs-history")
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"File name where minibuffer history is saved to and loaded from.
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The minibuffer history is a series of Lisp expressions loaded
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automatically when `savehist-mode' is turned on. See `savehist-mode'
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for more details.
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If you want your minibuffer history shared between Emacs and XEmacs,
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customize this value and make sure that `savehist-coding-system' is
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set to a coding system that exists in both emacsen."
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:type 'file
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:group 'savehist)
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(defcustom savehist-file-modes #o600
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"Default permissions of the history file.
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This is decimal, not octal. The default is 384 (0600 in octal).
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Set to nil to use the default permissions that Emacs uses, typically
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mandated by umask. The default is a bit more restrictive to protect
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the user's privacy."
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:type 'integer
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:group 'savehist)
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(defcustom savehist-autosave-interval (* 5 60)
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"The interval between autosaves of minibuffer history.
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If set to nil, disables timer-based autosaving."
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:type '(choice (const :tag "Disabled" nil)
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(integer :tag "Seconds"))
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:group 'savehist)
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(defcustom savehist-mode-hook nil
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"Hook called when `savehist-mode' is turned on."
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:type 'hook
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:group 'savehist)
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(defcustom savehist-save-hook nil
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"Hook called by `savehist-save' before saving the variables.
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You can use this hook to influence choice and content of variables to
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save."
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:type 'hook
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:group 'savehist)
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;; This should be capable of representing characters used by Emacs.
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;; We prefer UTF-8 over ISO 2022 because it is well-known outside
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;; Mule. XEmacs prior to 21.5 had UTF-8 provided by an external
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;; package which may not be loaded, which is why we check for version.
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(defvar savehist-coding-system (if (and (featurep 'xemacs)
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(<= emacs-major-version 21)
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(< emacs-minor-version 5))
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'iso-2022-8 'utf-8-unix)
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"The coding system savehist uses for saving the minibuffer history.
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Changing this value while Emacs is running is supported, but considered
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unwise, unless you know what you are doing.")
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;; Internal variables.
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(defvar savehist-timer nil)
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(defvar savehist-last-checksum nil)
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(defvar savehist-minibuffer-history-variables nil
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"List of minibuffer histories.
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The contents of this variable is built while Emacs is running, and saved
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along with minibuffer history. You can change its value off
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`savehist-save-hook' to influence which variables are saved.")
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(defconst savehist-no-conversion (if (featurep 'xemacs) 'binary 'no-conversion)
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"Coding system without any conversion.
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This is used for calculating an internal checksum. Should be as fast
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as possible, ideally simply exposing the internal representation of
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buffer text.")
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(defvar savehist-loaded nil
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"Whether the history has already been loaded.
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This prevents toggling `savehist-mode' from destroying existing
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minibuffer history.")
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(when (featurep 'xemacs)
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;; Must declare this under XEmacs, which doesn't have built-in
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;; minibuffer history truncation.
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(defvar history-length 100))
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;; Functions.
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;;;###autoload
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(define-minor-mode savehist-mode
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"Toggle saving of minibuffer history (Savehist mode).
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With a prefix argument ARG, enable Savehist mode if ARG is
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positive, and disable it otherwise. If called from Lisp, enable
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the mode if ARG is omitted or nil.
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When Savehist mode is enabled, minibuffer history is saved
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periodically and when exiting Emacs. When Savehist mode is
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enabled for the first time in an Emacs session, it loads the
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previous minibuffer history from `savehist-file'.
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This mode should normally be turned on from your Emacs init file.
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Calling it at any other time replaces your current minibuffer
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histories, which is probably undesirable."
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:global t
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(if (not savehist-mode)
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(savehist-uninstall)
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(when (and (not savehist-loaded)
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(file-exists-p savehist-file))
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(condition-case errvar
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(progn
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;; Don't set coding-system-for-read -- we rely on the
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;; coding cookie to convey that information. That way, if
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;; the user changes the value of savehist-coding-system,
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;; we can still correctly load the old file.
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(load savehist-file nil (not (called-interactively-p 'interactive)))
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(setq savehist-loaded t))
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(error
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;; Don't install the mode if reading failed. Doing so would
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;; effectively destroy the user's data at the next save.
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(setq savehist-mode nil)
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(savehist-uninstall)
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(signal (car errvar) (cdr errvar)))))
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(savehist-install)))
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(defun savehist-load ()
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"Load the variables stored in `savehist-file' and turn on `savehist-mode'.
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If `savehist-file' is in the old format that doesn't record
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the value of `savehist-minibuffer-history-variables', that
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value is deducted from the contents of the file."
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(declare (obsolete savehist-mode "22.1"))
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(savehist-mode 1)
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;; Old versions of savehist distributed with XEmacs didn't save
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;; savehist-minibuffer-history-variables. If that variable is nil
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;; after loading the file, try to intuit the intended value.
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(when (null savehist-minibuffer-history-variables)
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(setq savehist-minibuffer-history-variables
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(with-temp-buffer
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(ignore-errors
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(insert-file-contents savehist-file))
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(let ((vars ()) form)
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(while (setq form (condition-case nil
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(read (current-buffer)) (error nil)))
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;; Each form read is of the form (setq VAR VALUE).
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;; Collect VAR, i.e. (nth form 1).
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(push (nth 1 form) vars))
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vars)))))
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(defun savehist-install ()
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"Hook savehist into Emacs.
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Normally invoked by calling `savehist-mode' to set the minor mode.
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Installs `savehist-autosave' in `kill-emacs-hook' and on a timer.
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To undo this, call `savehist-uninstall'."
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(add-hook 'minibuffer-setup-hook 'savehist-minibuffer-hook)
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(add-hook 'kill-emacs-hook 'savehist-autosave)
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;; Install an invocation of savehist-autosave on a timer. This
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;; should not cause noticeable delays for users -- savehist-autosave
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;; executes in under 5 ms on my system.
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(when (and savehist-autosave-interval
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(null savehist-timer))
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(setq savehist-timer
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(if (featurep 'xemacs)
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(start-itimer
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"savehist" 'savehist-autosave savehist-autosave-interval
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savehist-autosave-interval)
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(run-with-timer savehist-autosave-interval
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savehist-autosave-interval 'savehist-autosave)))))
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(defun savehist-uninstall ()
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"Undo installing savehist.
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Normally invoked by calling `savehist-mode' to unset the minor mode."
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(remove-hook 'minibuffer-setup-hook 'savehist-minibuffer-hook)
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(remove-hook 'kill-emacs-hook 'savehist-autosave)
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(when savehist-timer
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(if (featurep 'xemacs)
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(delete-itimer savehist-timer)
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(cancel-timer savehist-timer))
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(setq savehist-timer nil)))
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;; From XEmacs?
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(defvar print-readably)
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(defvar print-string-length)
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(defun savehist-save (&optional auto-save)
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"Save the values of minibuffer history variables.
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Unbound symbols referenced in `savehist-additional-variables' are ignored.
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If AUTO-SAVE is non-nil, compare the saved contents to the one last saved,
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and don't save the buffer if they are the same."
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(interactive)
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(with-temp-buffer
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(insert
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(format ";; -*- mode: emacs-lisp; coding: %s -*-\n" savehist-coding-system)
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";; Minibuffer history file, automatically generated by `savehist'.\n\n")
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(run-hooks 'savehist-save-hook)
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(let ((print-length nil)
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(print-string-length nil)
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(print-level nil)
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(print-readably t)
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(print-quoted t))
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;; During the 24.3 development, read-passwd had a bug which resulted in
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;; the passwords being saved by savehist. Trim them, retroactively.
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;; This code can be removed after the 24.3 release.
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(dolist (sym savehist-minibuffer-history-variables)
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(if (and (symbolp sym) (equal (symbol-name sym) "forget-history"))
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(setq savehist-minibuffer-history-variables
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(delq sym savehist-minibuffer-history-variables))))
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;; Save the minibuffer histories, along with the value of
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;; savehist-minibuffer-history-variables itself.
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(when savehist-save-minibuffer-history
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(prin1 `(setq savehist-minibuffer-history-variables
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',savehist-minibuffer-history-variables)
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(current-buffer))
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(insert ?\n)
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(dolist (symbol savehist-minibuffer-history-variables)
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(when (and (boundp symbol)
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(not (memq symbol savehist-ignored-variables)))
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(let ((value (savehist-trim-history (symbol-value symbol)))
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excess-space)
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(when value ; Don't save empty histories.
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(insert "(setq ")
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(prin1 symbol (current-buffer))
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(insert " '(")
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;; We will print an extra space before the first element.
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;; Record where that is.
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(setq excess-space (point))
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;; Print elements of VALUE one by one, carefully.
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(dolist (elt value)
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(let ((start (point)))
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(insert " ")
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;; Try to print and then to read an element.
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(condition-case nil
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(progn
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(prin1 elt (current-buffer))
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(save-excursion
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(goto-char start)
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(read (current-buffer))))
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(error
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;; If writing or reading gave an error, comment it out.
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(goto-char start)
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(insert "\n")
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(while (not (eobp))
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(insert ";;; ")
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(forward-line 1))
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(insert "\n")))
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(goto-char (point-max))))
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;; Delete the extra space before the first element.
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(save-excursion
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(goto-char excess-space)
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(if (eq (following-char) ?\s)
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(delete-region (point) (1+ (point)))))
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(insert "))\n"))))))
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;; Save the additional variables.
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(dolist (symbol savehist-additional-variables)
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(when (boundp symbol)
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(let ((value (symbol-value symbol)))
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(when (savehist-printable value)
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(prin1 `(setq ,symbol ',value) (current-buffer))
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(insert ?\n))))))
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;; If autosaving, avoid writing if nothing has changed since the
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;; last write.
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(let ((checksum (md5 (current-buffer) nil nil savehist-no-conversion)))
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(unless (and auto-save (equal checksum savehist-last-checksum))
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;; Set file-precious-flag when saving the buffer because we
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;; don't want a half-finished write ruining the entire
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;; history. Remember that this is run from a timer and from
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;; kill-emacs-hook, and also that multiple Emacs instances
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;; could write to this file at once.
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(let ((file-precious-flag t)
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(coding-system-for-write savehist-coding-system))
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(write-region (point-min) (point-max) savehist-file nil
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(unless (called-interactively-p 'interactive) 'quiet)))
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(when savehist-file-modes
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(set-file-modes savehist-file savehist-file-modes))
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(setq savehist-last-checksum checksum)))))
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(defun savehist-autosave ()
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"Save the minibuffer history if it has been modified since the last save.
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Does nothing if `savehist-mode' is off."
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(when savehist-mode
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(savehist-save t)))
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(defun savehist-trim-history (value)
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"Retain only the first `history-length' items in VALUE.
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Only used under XEmacs, which doesn't (yet) implement automatic
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trimming of history lists to `history-length' items."
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(if (and (featurep 'xemacs)
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(natnump history-length)
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(> (length value) history-length))
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;; Equivalent to `(subseq value 0 history-length)', but doesn't
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;; need cl-extra at run-time.
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(loop repeat history-length collect (pop value))
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value))
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(defun savehist-printable (value)
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"Return non-nil if VALUE is printable."
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(cond
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;; Quick response for oft-encountered types known to be printable.
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((numberp value))
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((symbolp value))
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;; String without properties
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((and (stringp value)
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(equal-including-properties value (substring-no-properties value))))
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(t
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;; For others, check explicitly.
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(with-temp-buffer
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(condition-case nil
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(let ((print-readably t) (print-level nil))
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;; Print the value into a buffer...
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(prin1 value (current-buffer))
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;; ...and attempt to read it.
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(read (point-min-marker))
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;; The attempt worked: the object is printable.
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t)
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;; The attempt failed: the object is not printable.
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(error nil))))))
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(defun savehist-minibuffer-hook ()
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(unless (or (eq minibuffer-history-variable t)
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;; XEmacs sets minibuffer-history-variable to t to mean "no
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;; history is being recorded".
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(memq minibuffer-history-variable savehist-ignored-variables))
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(add-to-list 'savehist-minibuffer-history-variables
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minibuffer-history-variable)))
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(provide 'savehist)
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;;; savehist.el ends here
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