legacy-dotfiles/emacs.d/elisp/linum-ex.el
2011-05-27 00:36:44 +02:00

287 lines
11 KiB
EmacsLisp

;;; linum-ex.el --- Display line numbers to the left of buffers
;; originally derived from linum.el, which is
;; Copyright (C) 2007, 2008 Markus Triska
;; modifications in linum-ex.el provided by: Dino Chiesa
;; Author: Markus Triska <markus.triska@gmx.at>
;; Last saved: <2011-May-23 12:47:18>
;;
;; Keywords: convenience
;; This file is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 3, or (at your option)
;; any later version.
;; This file is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;; Commentary:
;; Display line numbers for the current buffer. Copy linum-ex.el to your
;; load-path and add to your .emacs:
;; (require 'linum-ex)
;; Then toggle display of line numbers with M-x linum-mode. To enable
;; line numbering in all buffers, use M-x global-linum-mode.
;; =======================================================
;;
;; Dino Chiesa Mon, 23 May 2011 12:00
;;
;; notes on changes.
;;
;; The problem with the original linum module is that it updated the
;; line numbers after every scroll and possibly every command. This
;; works for small files but not for files with 100,000+ lines. Even
;; with linum-delay turned on, linum had the effect of "Freezing" the
;; display when the user was continuously scrolling. It also introduced
;; noticeable delays when scrolling only momentarily.
;;
;; One idea for working around that is to use run-with-idle-timer, and
;; only update the line numbers when emacs is idle. One can set a single
;; timer, for, say 0.1s, and then when emacs goes idle for that period,
;; the line numbers will be updated. Seems like the perfect fit,
;; but there's a problem: a timer created via run-with-idle-timer
;; gets canceled after being delayed 10 times.
;;
;; So if the after-scroll event sets up a timer via run-with-idle-timer,
;; only when no timer has been set, the timer may get canceled silently,
;; by timer.el . Look at `timer-max-repeats'.
;;
;; This happens if emacs is busy for 1s, as for example when the user is
;; holding pgdn to continuously scroll through a large document. If the
;; timer doesn't fire, then the line numbers don't ever get updated.
;;
;; To avoid that pitfall, this code can set run-with-idle-timer for
;; every scroll event, and handle the delay explicitly, right here. The
;; way to do it is, within the after-scroll event, store the "last
;; scrolled" time, and then call `run-with-idle-timer'. There may be
;; other outstanding timer events, but we don't care. In the function
;; that gets called when the timer fires, check to see if a reasonable
;; interval (Say 0.1s) has elapsed since the last scroll event. If so,
;; do linum-update. If not, it means scrolling is still happening, so,
;; do nothing. All this applies only if linum-delay is non-nil.
;;
;; The result is that timers fire constantly while the user is
;; continuously scrolling, but the line numbers get updated only after
;; the user stops scrolling. The user experiences no delay while
;; scrolling, but (unfortunately) gets no line numbers either. The user
;; sees updated line numbers immediately when he stops.
;;
;; =======================================================
;;; Code:
(require 'timer)
(defconst linum-version "0.991")
(defvar linum-overlays nil "Overlays used in this buffer.")
(defvar linum-available nil "Overlays available for reuse.")
(defvar linum-before-numbering-hook nil
"Functions run in each buffer before line numbering starts.")
(mapc #'make-variable-buffer-local '(linum-overlays linum-available))
(defgroup linum nil
"Show line numbers to the left of buffers"
:group 'convenience)
;;;###autoload
(defcustom linum-format 'dynamic
"Format used to display line numbers. Either a format string
like \"%7d\", 'dynamic to adapt the width as needed, or a
function that is called with a line number as its argument and
should evaluate to a string to be shown on that line. See also
`linum-before-numbering-hook'."
:group 'linum
:type 'sexp)
(defface linum
'((t :inherit (shadow default)))
"Face for displaying line numbers in the display margin."
:group 'linum)
(defcustom linum-eager t
"Whether line numbers should be updated after each command.
The conservative setting `nil' might miss some buffer changes,
and you have to scroll or press C-l to update the numbers."
:group 'linum
:type 'boolean)
(defcustom linum-delay nil
"Delay updates to give Emacs a chance for other changes."
:group 'linum
:type 'boolean)
(defvar linum--delay-time 0.1
"Delay time. See also `linum-delay'")
(defvar linum--last-scroll nil
"Time of last scroll event. See also `linum-delay'")
(defvar linum--last-cmd nil
"Time of last command. See also `linum-delay'")
(defvar linum--win nil
"Window of the last scroll event. See also `linum-delay'")
;;;###autoload
(define-minor-mode linum-mode
"Toggle display of line numbers in the left marginal area."
:lighter "" ; for desktop.el
(if linum-mode
(progn
(if linum-eager
(add-hook 'post-command-hook 'linum-post-command)
(add-hook 'after-change-functions 'linum-after-change nil t))
(add-hook 'window-scroll-functions 'linum-after-scroll nil t)
;; mistake in Emacs: window-size-change-functions cannot be local
(add-hook 'window-size-change-functions 'linum-after-size)
(add-hook 'change-major-mode-hook 'linum-delete-overlays nil t)
(add-hook 'window-configuration-change-hook
'linum-after-config nil t)
(set (make-local-variable 'linum--win) nil)
(set (make-local-variable 'linum--last-scroll) nil)
(set (make-local-variable 'linum--last-cmd) nil)
(linum-update-current))
(remove-hook 'post-command-hook 'linum-post-command t)
(remove-hook 'window-size-change-functions 'linum-after-size)
(remove-hook 'window-scroll-functions 'linum-after-scroll t)
(remove-hook 'after-change-functions 'linum-after-change t)
(remove-hook 'window-configuration-change-hook 'linum-after-config t)
(remove-hook 'change-major-mode-hook 'linum-delete-overlays t)
(linum-delete-overlays)))
;;;###autoload
(define-globalized-minor-mode global-linum-mode linum-mode linum-on)
(defun linum-on ()
(unless (minibufferp)
(linum-mode 1)))
(defun linum-delete-overlays ()
"Delete all overlays displaying line numbers for this buffer."
(mapc #'delete-overlay linum-overlays)
(setq linum-overlays nil)
(dolist (w (get-buffer-window-list (current-buffer) nil t))
(set-window-margins w 0)))
(defun linum-update-current ()
"Update line numbers for the current buffer."
(linum-update (current-buffer)))
(defun linum-update (buffer)
"Update line numbers for all windows displaying BUFFER."
(with-current-buffer buffer
(when linum-mode
(setq linum-available linum-overlays)
(setq linum-overlays nil)
(save-excursion
(mapc #'linum-update-window
(get-buffer-window-list buffer nil 'visible)))
(mapc #'delete-overlay linum-available)
(setq linum-available nil
linum--last-cmd nil
linum--last-scroll nil))))
(defun linum-update-window (win)
"Update line numbers for the portion visible in window WIN."
(goto-char (window-start win))
(let ((line (line-number-at-pos))
(limit (window-end win t))
(fmt (cond ((stringp linum-format) linum-format)
((eq linum-format 'dynamic)
(let ((w (length (number-to-string
(count-lines (point-min) (point-max))))))
(concat "%" (number-to-string w) "d")))))
(width 0))
(run-hooks 'linum-before-numbering-hook)
;; Create an overlay (or reuse an existing one) for each
;; line visible in this window, if necessary.
(while (and (not (eobp)) (<= (point) limit))
(let* ((str (if fmt
(propertize (format fmt line) 'face 'linum)
(funcall linum-format line)))
(visited (catch 'visited
(dolist (o (overlays-in (point) (point)))
(when (string= (overlay-get o 'linum-str) str)
(unless (memq o linum-overlays)
(push o linum-overlays))
(setq linum-available (delete o linum-available))
(throw 'visited t))))))
(setq width (max width (length str)))
(unless visited
(let ((ov (if (null linum-available)
(make-overlay (point) (point))
(move-overlay (pop linum-available) (point) (point)))))
(push ov linum-overlays)
(overlay-put ov 'before-string
(propertize " " 'display `((margin left-margin) ,str)))
(overlay-put ov 'linum-str str))))
(forward-line)
(setq line (1+ line)))
(set-window-margins win width)))
(defun linum-after-change (beg end len)
;; update overlays on deletions, and after newlines are inserted
(when (or (= beg end)
(= end (point-max))
;; TODO: use string-match-p with CVS or new release
(string-match "\n" (buffer-substring-no-properties beg end)))
(linum-update-current)))
(defun linum--after-scroll-fired ()
(if linum--last-scroll
(let ((now (current-time))
(one-moment-after-scroll (timer-relative-time linum--last-scroll linum--delay-time)))
(if (time-less-p one-moment-after-scroll now)
(linum-update linum--win)))))
(defun linum-after-scroll (win start)
(if linum-delay
(progn
(setq linum--win (window-buffer win))
(setq linum--last-scroll (current-time))
(run-with-idle-timer linum--delay-time nil 'linum--after-scroll-fired))
(linum-update (window-buffer win))))
(defun linum--post-command-fired ()
(if linum--last-cmd
(let ((now (current-time))
(one-moment-after-cmd (timer-relative-time linum--last-cmd linum--delay-time)))
(if (time-less-p one-moment-after-cmd now)
(linum-update-current)))))
(defun linum-post-command ()
(if linum-delay
(progn
(setq linum--win (window-buffer win))
(setq linum--last-cmd (current-time))
(run-with-idle-timer linum--delay-time nil 'linum--post-command-fired))
(linum-update-current)))
(defun linum-after-size (frame)
(linum-after-config))
(defun linum-after-config ()
(walk-windows (lambda (w) (linum-update (window-buffer w))) nil 'visible))
(provide 'linum-ex)
;;; linum-ex.el ends here