lisp/linum.el

   1 ;;; linum.el --- display line numbers in the left margin -*- lexical-binding: t -*-
   2
   3 ;; Copyright (C) 2008-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Markus Triska <markus.triska@gmx.at>
   6 ;; Maintainer: emacs-devel@gnu.org
   7 ;; Keywords: convenience
   8 ;; Version: 0.9x
   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 3 of the License, or
  15 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; Display line numbers for the current buffer.
  28 ;;
  29 ;; Toggle display of line numbers with M-x linum-mode.  To enable
  30 ;; line numbering in all buffers, use M-x global-linum-mode.
  31
  32 ;;; Code:
  33
  34 (defconst linum-version "0.9x")
  35
  36 (defvar linum-overlays nil "Overlays used in this buffer.")
  37 (defvar linum-available nil "Overlays available for reuse.")
  38 (defvar linum-before-numbering-hook nil
  39   "Functions run in each buffer before line numbering starts.")
  40
  41 (mapc #'make-variable-buffer-local '(linum-overlays linum-available))
  42
  43 (defgroup linum nil
  44   "Show line numbers in the left margin."
  45   :group 'convenience)
  46
  47 (defcustom linum-format 'dynamic
  48   "Format used to display line numbers.
  49 Either a format string like \"%7d\", `dynamic' to adapt the width
  50 as needed, or a function that is called with a line number as its
  51 argument and should evaluate to a string to be shown on that line.
  52 See also `linum-before-numbering-hook'."
  53   :group 'linum
  54   :type '(choice (string :tag "Format string")
  55                  (const :tag "Dynamic width" dynamic)
  56                  (function :tag "Function")))
  57
  58 (defface linum
  59   '((t :inherit (shadow default)))
  60   "Face for displaying line numbers in the display margin."
  61   :group 'linum)
  62
  63 (defcustom linum-eager t
  64   "Whether line numbers should be updated after each command.
  65 The conservative setting nil might miss some buffer changes,
  66 and you have to scroll or press \\[recenter-top-bottom] to update the numbers."
  67   :group 'linum
  68   :type 'boolean)
  69
  70 (defcustom linum-delay nil
  71   "Delay updates to give Emacs a chance for other changes."
  72   :group 'linum
  73   :type 'boolean)
  74
  75 ;;;###autoload
  76 (define-minor-mode linum-mode
  77   "Toggle display of line numbers in the left margin (Linum mode).
  78 With a prefix argument ARG, enable Linum mode if ARG is positive,
  79 and disable it otherwise.  If called from Lisp, enable the mode
  80 if ARG is omitted or nil.
  81
  82 Linum mode is a buffer-local minor mode."
  83   :lighter ""                           ; for desktop.el
  84   (if linum-mode
  85       (progn
  86         (if linum-eager
  87             (add-hook 'post-command-hook (if linum-delay
  88                                              'linum-schedule
  89                                            'linum-update-current) nil t)
  90           (add-hook 'after-change-functions 'linum-after-change nil t))
  91         (add-hook 'window-scroll-functions 'linum-after-scroll nil t)
  92         ;; Using both window-size-change-functions and
  93         ;; window-configuration-change-hook seems redundant. --Stef
  94         ;; (add-hook 'window-size-change-functions 'linum-after-size nil t)
  95         (add-hook 'change-major-mode-hook 'linum-delete-overlays nil t)
  96         (add-hook 'window-configuration-change-hook
  97                   ;; FIXME: If the buffer is shown in N windows, this
  98                   ;; will be called N times rather than once.  We should use
  99                   ;; something like linum-update-window instead.
 100                   'linum-update-current nil t)
 101         (linum-update-current))
 102     (remove-hook 'post-command-hook 'linum-update-current t)
 103     (remove-hook 'post-command-hook 'linum-schedule t)
 104     ;; (remove-hook 'window-size-change-functions 'linum-after-size t)
 105     (remove-hook 'window-scroll-functions 'linum-after-scroll t)
 106     (remove-hook 'after-change-functions 'linum-after-change t)
 107     (remove-hook 'window-configuration-change-hook 'linum-update-current t)
 108     (remove-hook 'change-major-mode-hook 'linum-delete-overlays t)
 109     (linum-delete-overlays)))
 110
 111 ;;;###autoload
 112 (define-globalized-minor-mode global-linum-mode linum-mode linum-on)
 113
 114 (defun linum-on ()
 115   (unless (minibufferp)
 116     (linum-mode 1)))
 117
 118 (defun linum-delete-overlays ()
 119   "Delete all overlays displaying line numbers for this buffer."
 120   (mapc #'delete-overlay linum-overlays)
 121   (setq linum-overlays nil)
 122   (dolist (w (get-buffer-window-list (current-buffer) nil t))
 123     ;; restore margins if needed FIXME: This still fails if the
 124     ;; "other" mode has incidentally set margins to exactly what linum
 125     ;; had: see bug#20674 for a similar workaround in nlinum.el
 126     (let ((set-margins (window-parameter w 'linum--set-margins))
 127           (current-margins (window-margins w)))
 128       (when (and set-margins
 129                  (equal set-margins current-margins))
 130         (set-window-margins w 0 (cdr current-margins))
 131         (set-window-parameter w 'linum--set-margins nil)))))
 132
 133 (defun linum-update-current ()
 134   "Update line numbers for the current buffer."
 135   (linum-update (current-buffer)))
 136
 137 (defun linum-update (buffer)
 138   "Update line numbers for all windows displaying BUFFER."
 139   (with-current-buffer buffer
 140     (when linum-mode
 141       (setq linum-available linum-overlays)
 142       (setq linum-overlays nil)
 143       (save-excursion
 144         (mapc #'linum-update-window
 145               (get-buffer-window-list buffer nil 'visible)))
 146       (mapc #'delete-overlay linum-available)
 147       (setq linum-available nil))))
 148
 149 ;; Behind display-graphic-p test.
 150 (declare-function font-info "font.c" (name &optional frame))
 151
 152 (defun linum--face-width (face)
 153   (let ((info (font-info (face-font face)))
 154         width)
 155     (setq width (aref info 11))
 156     (if (<= width 0)
 157         (setq width (aref info 10)))
 158     width))
 159
 160 (defun linum-update-window (win)
 161   "Update line numbers for the portion visible in window WIN."
 162   (goto-char (window-start win))
 163   (let ((line (line-number-at-pos))
 164         (limit (window-end win t))
 165         (fmt (cond ((stringp linum-format) linum-format)
 166                    ((eq linum-format 'dynamic)
 167                     (let ((w (length (number-to-string
 168                                       (count-lines (point-min) (point-max))))))
 169                       (concat "%" (number-to-string w) "d")))))
 170         (width 0))
 171     (run-hooks 'linum-before-numbering-hook)
 172     ;; Create an overlay (or reuse an existing one) for each
 173     ;; line visible in this window, if necessary.
 174     (while (and (not (eobp)) (< (point) limit))
 175       (let* ((str (if fmt
 176                       (propertize (format fmt line) 'face 'linum)
 177                     (funcall linum-format line)))
 178              (visited (catch 'visited
 179                         (dolist (o (overlays-in (point) (point)))
 180                           (when (equal-including-properties
 181                                  (overlay-get o 'linum-str) str)
 182                             (unless (memq o linum-overlays)
 183                               (push o linum-overlays))
 184                             (setq linum-available (delq o linum-available))
 185                             (throw 'visited t))))))
 186         (setq width (max width (length str)))
 187         (unless visited
 188           (let ((ov (if (null linum-available)
 189                         (make-overlay (point) (point))
 190                       (move-overlay (pop linum-available) (point) (point)))))
 191             (push ov linum-overlays)
 192             (overlay-put ov 'before-string
 193                          (propertize " " 'display `((margin left-margin) ,str)))
 194             (overlay-put ov 'linum-str str))))
 195       ;; Text may contain those nasty intangible properties, but that
 196       ;; shouldn't prevent us from counting those lines.
 197       (let ((inhibit-point-motion-hooks t))
 198         (forward-line))
 199       (setq line (1+ line)))
 200     (when (display-graphic-p)
 201       (setq width (ceiling
 202                    (/ (* width 1.0 (linum--face-width 'linum))
 203                       (frame-char-width)))))
 204     ;; open up space in the left margin, if needed, and record that
 205     ;; fact as the window-parameter `linum--set-margins'
 206     (let ((existing-margins (window-margins win)))
 207       (when (> width (or (car existing-margins) 0))
 208         (set-window-margins win width (cdr existing-margins))
 209         (set-window-parameter win 'linum--set-margins (window-margins win))))))
 210
 211 (defun linum-after-change (beg end _len)
 212   ;; update overlays on deletions, and after newlines are inserted
 213   (when (or (= beg end)
 214             (= end (point-max))
 215             (string-match-p "\n" (buffer-substring-no-properties beg end)))
 216     (linum-update-current)))
 217
 218 (defun linum-after-scroll (win _start)
 219   (linum-update (window-buffer win)))
 220
 221 ;; (defun linum-after-size (frame)
 222 ;;   (linum-after-config))
 223
 224 (defun linum-schedule ()
 225   ;; schedule an update; the delay gives Emacs a chance for display changes
 226   (run-with-idle-timer 0 nil #'linum-update-current))
 227
 228 ;; (defun linum-after-config ()
 229 ;;   (walk-windows (lambda (w) (linum-update (window-buffer w))) nil 'visible))
 230
 231 (defun linum-unload-function ()
 232   "Unload the Linum library."
 233   (global-linum-mode -1)
 234   ;; continue standard unloading
 235   nil)
 236
 237 (provide 'linum)
 238
 239 ;;; linum.el ends here