lisp/xt-mouse.el

   1 ;;; xt-mouse.el --- support the mouse when emacs run in an xterm -*- lexical-binding: t -*-
   2
   3 ;; Copyright (C) 1994, 2000-2016 Free Software Foundation, Inc.
   4
   5 ;; Author: Per Abrahamsen <abraham@dina.kvl.dk>
   6 ;; Keywords: mouse, terminals
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; Enable mouse support when running inside an xterm.
  26
  27 ;; This is actually useful when you are running X11 locally, but is
  28 ;; working on remote machine over a modem line or through a gateway.
  29
  30 ;; It works by translating xterm escape codes into generic emacs mouse
  31 ;; events so it should work with any package that uses the mouse.
  32
  33 ;; You don't have to turn off xterm mode to use the normal xterm mouse
  34 ;; functionality, it is still available by holding down the SHIFT key
  35 ;; when you press the mouse button.
  36
  37 ;;; Todo:
  38
  39 ;; Support multi-click -- somehow.
  40
  41 ;;; Code:
  42
  43 (defvar xterm-mouse-debug-buffer nil)
  44
  45 (defun xterm-mouse-translate (_event)
  46   "Read a click and release event from XTerm."
  47   (xterm-mouse-translate-1))
  48
  49 (defun xterm-mouse-translate-extended (_event)
  50   "Read a click and release event from XTerm.
  51 Similar to `xterm-mouse-translate', but using the \"1006\"
  52 extension, which supports coordinates >= 231 (see
  53 http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)."
  54   (xterm-mouse-translate-1 1006))
  55
  56 (defun xterm-mouse-translate-1 (&optional extension)
  57   (save-excursion
  58     (let* ((event (xterm-mouse-event extension))
  59            (ev-command (nth 0 event))
  60            (ev-data    (nth 1 event))
  61            (ev-where   (nth 1 ev-data))
  62            (vec (vector event))
  63            (is-move (eq 'mouse-movement ev-command))
  64            (is-down (string-match "down-" (symbol-name ev-command))))
  65
  66       ;; Mouse events symbols must have an 'event-kind property with
  67       ;; the value 'mouse-click.
  68       (when ev-command (put ev-command 'event-kind 'mouse-click))
  69
  70       (cond
  71        ((null event) nil)               ;Unknown/bogus byte sequence!
  72        (is-down
  73         (setf (terminal-parameter nil 'xterm-mouse-last-down) event)
  74         vec)
  75        (is-move vec)
  76        (t
  77         (let* ((down (terminal-parameter nil 'xterm-mouse-last-down))
  78                (down-data (nth 1 down))
  79                (down-where (nth 1 down-data)))
  80           (setf (terminal-parameter nil 'xterm-mouse-last-down) nil)
  81           (cond
  82            ((null down)
  83             ;; This is an "up-only" event.  Pretend there was an up-event
  84             ;; right before and keep the up-event for later.
  85             (push event unread-command-events)
  86             (vector (cons (intern (replace-regexp-in-string
  87                                    "\\`\\([ACMHSs]-\\)*" "\\&down-"
  88                                    (symbol-name ev-command) t))
  89                           (cdr event))))
  90            ((equal ev-where down-where) vec)
  91            (t
  92             (let ((drag (if (symbolp ev-where)
  93                             0           ;FIXME: Why?!?
  94                           (list (intern (replace-regexp-in-string
  95                                          "\\`\\([ACMHSs]-\\)*" "\\&drag-"
  96                                          (symbol-name ev-command) t))
  97                                 down-data ev-data))))
  98               (if (null track-mouse)
  99                   (vector drag)
 100                 (push drag unread-command-events)
 101                 (vector (list 'mouse-movement ev-data))))))))))))
 102
 103 ;; These two variables have been converted to terminal parameters.
 104 ;;
 105 ;;(defvar xterm-mouse-x 0
 106 ;;  "Position of last xterm mouse event relative to the frame.")
 107 ;;
 108 ;;(defvar xterm-mouse-y 0
 109 ;;  "Position of last xterm mouse event relative to the frame.")
 110
 111 (defvar xt-mouse-epoch nil)
 112
 113 ;; Indicator for the xterm-mouse mode.
 114
 115 (defun xterm-mouse-position-function (pos)
 116   "Bound to `mouse-position-function' in XTerm mouse mode."
 117   (when (terminal-parameter nil 'xterm-mouse-x)
 118     (setcdr pos (cons (terminal-parameter nil 'xterm-mouse-x)
 119                       (terminal-parameter nil 'xterm-mouse-y))))
 120   pos)
 121
 122 (defun xterm-mouse-truncate-wrap (f)
 123   "Truncate with wrap-around."
 124   (condition-case nil
 125       ;; First try the built-in truncate, in case there's no overflow.
 126       (truncate f)
 127     ;; In case of overflow, do wraparound by hand.
 128     (range-error
 129      ;; In our case, we wrap around every 3 days or so, so if we assume
 130      ;; a maximum of 65536 wraparounds, we're safe for a couple years.
 131      ;; Using a power of 2 makes rounding errors less likely.
 132      (let* ((maxwrap (* 65536 2048))
 133             (dbig (truncate (/ f maxwrap)))
 134             (fdiff (- f (* 1.0 maxwrap dbig))))
 135        (+ (truncate fdiff) (* maxwrap dbig))))))
 136
 137 (defcustom xterm-mouse-utf-8 nil
 138   "Non-nil if UTF-8 coordinates should be used to read mouse coordinates.
 139 Set this to non-nil if you are sure that your terminal
 140 understands UTF-8 coordinates, but not SGR coordinates."
 141   :version "25.1"
 142   :type 'boolean
 143   :risky t
 144   :group 'xterm)
 145
 146 (defun xterm-mouse--read-coordinate ()
 147   "Read a mouse coordinate from the current terminal.
 148 If `xterm-mouse-utf-8' was non-nil when
 149 `turn-on-xterm-mouse-tracking-on-terminal' was called, reads the
 150 coordinate as an UTF-8 code unit sequence; otherwise, reads a
 151 single byte."
 152   (let ((previous-keyboard-coding-system (keyboard-coding-system)))
 153     (unwind-protect
 154         (progn
 155           (set-keyboard-coding-system
 156            (if (terminal-parameter nil 'xterm-mouse-utf-8)
 157                'utf-8-unix
 158              'no-conversion))
 159           ;; Wait only a little; we assume that the entire escape sequence
 160           ;; has already been sent when this function is called.
 161           (read-char nil nil 0.1))
 162       (set-keyboard-coding-system previous-keyboard-coding-system))))
 163
 164 ;; In default mode, each numeric parameter of XTerm's mouse report is
 165 ;; a single char, possibly encoded as utf-8.  The actual numeric
 166 ;; parameter then is obtained by subtracting 32 from the character
 167 ;; code.  In extended mode the parameters are returned as decimal
 168 ;; string delimited either by semicolons or for the last parameter by
 169 ;; one of the characters "m" or "M".  If the last character is a "m",
 170 ;; then the mouse event was a button release, else it was a button
 171 ;; press or a mouse motion.  Return value is a cons cell with
 172 ;; (NEXT-NUMERIC-PARAMETER . LAST-CHAR)
 173 (defun xterm-mouse--read-number-from-terminal (extension)
 174   (let (c)
 175     (if extension
 176         (let ((n 0))
 177           (while (progn
 178                    (setq c (read-char))
 179                    (<= ?0 c ?9))
 180             (setq n (+ (* 10 n) c (- ?0))))
 181           (cons n c))
 182       (cons (- (setq c (xterm-mouse--read-coordinate)) 32) c))))
 183
 184 ;; XTerm reports mouse events as
 185 ;; <EVENT-CODE> <X> <Y> in default mode, and
 186 ;; <EVENT-CODE> ";" <X> ";" <Y> <"M" or "m"> in extended mode.
 187 ;; The macro read-number-from-terminal takes care of reading
 188 ;; the response parameters appropriately.  The EVENT-CODE differs
 189 ;; slightly between default and extended mode.
 190 ;; Return a list (EVENT-TYPE-SYMBOL X Y).
 191 (defun xterm-mouse--read-event-sequence (&optional extension)
 192   (pcase-let*
 193       ((`(,code . ,_) (xterm-mouse--read-number-from-terminal extension))
 194        (`(,x . ,_) (xterm-mouse--read-number-from-terminal extension))
 195        (`(,y . ,c) (xterm-mouse--read-number-from-terminal extension))
 196        (wheel (/= (logand code 64) 0))
 197        (move (/= (logand code 32) 0))
 198        (ctrl (/= (logand code 16) 0))
 199        (meta (/= (logand code 8) 0))
 200        (shift (/= (logand code 4) 0))
 201        (down (and (not wheel)
 202                   (not move)
 203                   (if extension
 204                       (eq c ?M)
 205                     (/= (logand code 3) 3))))
 206        (btn (cond
 207              ((or extension down wheel)
 208               (+ (logand code 3) (if wheel 4 1)))
 209               ;; The default mouse protocol does not report the button
 210               ;; number in release events: extract the button number
 211               ;; from last button-down event.
 212              ((terminal-parameter nil 'xterm-mouse-last-down)
 213               (string-to-number
 214                (substring
 215                 (symbol-name
 216                  (car (terminal-parameter nil 'xterm-mouse-last-down)))
 217                 -1)))
 218              ;; Spurious release event without previous button-down
 219              ;; event: assume, that the last button was button 1.
 220              (t 1)))
 221        (sym (if move 'mouse-movement
 222               (intern (concat (if ctrl "C-" "")
 223                               (if meta "M-" "")
 224                               (if shift "S-" "")
 225                               (if down "down-" "")
 226                               "mouse-"
 227                               (number-to-string btn))))))
 228     (list sym (1- x) (1- y))))
 229
 230 (defun xterm-mouse--set-click-count (event click-count)
 231   (setcdr (cdr event) (list click-count))
 232   (let ((name (symbol-name (car event))))
 233     (when (string-match "\\(.*?\\)\\(\\(?:down-\\)?mouse-.*\\)" name)
 234       (setcar event
 235               (intern (concat (match-string 1 name)
 236                               (if (= click-count 2)
 237                                   "double-" "triple-")
 238                               (match-string 2 name)))))))
 239
 240 (defun xterm-mouse-event (&optional extension)
 241   "Convert XTerm mouse event to Emacs mouse event.
 242 EXTENSION, if non-nil, means to use an extension to the usual
 243 terminal mouse protocol; we currently support the value 1006,
 244 which is the \"1006\" extension implemented in Xterm >= 277."
 245   (let ((click (cond ((memq extension '(1006 nil))
 246                       (xterm-mouse--read-event-sequence extension))
 247                      (t
 248                       (error "Unsupported XTerm mouse protocol")))))
 249     (when click
 250       (let* ((type (nth 0 click))
 251              (x    (nth 1 click))
 252              (y    (nth 2 click))
 253              ;; Emulate timestamp information.  This is accurate enough
 254              ;; for default value of mouse-1-click-follows-link (450msec).
 255              (timestamp (xterm-mouse-truncate-wrap
 256                          (* 1000
 257                             (- (float-time)
 258                                (or xt-mouse-epoch
 259                                    (setq xt-mouse-epoch (float-time)))))))
 260              (w (window-at x y))
 261              (ltrb (window-edges w))
 262              (left (nth 0 ltrb))
 263              (top (nth 1 ltrb))
 264              (posn (if w
 265                                 (posn-at-x-y (- x left) (- y top) w t)
 266                               (append (list nil 'menu-bar)
 267                              (nthcdr 2 (posn-at-x-y x y)))))
 268              (event (list type posn)))
 269         (setcar (nthcdr 3 posn) timestamp)
 270
 271         ;; Try to handle double/triple clicks.
 272         (let* ((last-click (terminal-parameter nil 'xterm-mouse-last-click))
 273                (last-type (nth 0 last-click))
 274                (last-name (symbol-name last-type))
 275                (last-time (nth 1 last-click))
 276                (click-count (nth 2 last-click))
 277                (this-time (float-time))
 278                (name (symbol-name type)))
 279           (cond
 280            ((not (string-match "down-" name))
 281             ;; For up events, make the up side match the down side.
 282             (setq this-time last-time)
 283             (when (and click-count (> click-count 1)
 284                        (string-match "down-" last-name)
 285                        (equal name (replace-match "" t t last-name)))
 286               (xterm-mouse--set-click-count event click-count)))
 287            ((not last-time) nil)
 288            ((and (> double-click-time (* 1000 (- this-time last-time)))
 289                  (equal last-name (replace-match "" t t name)))
 290             (setq click-count (1+ click-count))
 291             (xterm-mouse--set-click-count event click-count))
 292            (t (setq click-count 1)))
 293           (set-terminal-parameter nil 'xterm-mouse-last-click
 294                                   (list type this-time click-count)))
 295
 296         (set-terminal-parameter nil 'xterm-mouse-x x)
 297         (set-terminal-parameter nil 'xterm-mouse-y y)
 298         (setq last-input-event event)))))
 299
 300 ;;;###autoload
 301 (define-minor-mode xterm-mouse-mode
 302   "Toggle XTerm mouse mode.
 303 With a prefix argument ARG, enable XTerm mouse mode if ARG is
 304 positive, and disable it otherwise.  If called from Lisp, enable
 305 the mode if ARG is omitted or nil.
 306
 307 Turn it on to use Emacs mouse commands, and off to use xterm mouse commands.
 308 This works in terminal emulators compatible with xterm.  It only
 309 works for simple uses of the mouse.  Basically, only non-modified
 310 single clicks are supported.  When turned on, the normal xterm
 311 mouse functionality for such clicks is still available by holding
 312 down the SHIFT key while pressing the mouse button."
 313   :global t :group 'mouse
 314   (funcall (if xterm-mouse-mode 'add-hook 'remove-hook)
 315            'terminal-init-xterm-hook
 316            'turn-on-xterm-mouse-tracking-on-terminal)
 317   (if xterm-mouse-mode
 318       ;; Turn it on
 319       (progn
 320         (setq mouse-position-function #'xterm-mouse-position-function)
 321         (mapc #'turn-on-xterm-mouse-tracking-on-terminal (terminal-list)))
 322     ;; Turn it off
 323     (mapc #'turn-off-xterm-mouse-tracking-on-terminal (terminal-list))
 324     (setq mouse-position-function nil)))
 325
 326 (defun xterm-mouse-tracking-enable-sequence ()
 327   "Return a control sequence to enable XTerm mouse tracking.
 328 The returned control sequence enables basic mouse tracking, mouse
 329 motion events and finally extended tracking on terminals that
 330 support it.  The following escape sequences are understood by
 331 modern xterms:
 332
 333 \"\\e[?1000h\" \"Basic mouse mode\": Enables reports for mouse
 334             clicks.  There is a limit to the maximum row/column
 335             position (<= 223), which can be reported in this
 336             basic mode.
 337
 338 \"\\e[?1002h\" \"Mouse motion mode\": Enables reports for mouse
 339             motion events during dragging operations.
 340
 341 \"\\e[?1005h\" \"UTF-8 coordinate extension\": Enables an
 342             extension to the basic mouse mode, which uses UTF-8
 343             characters to overcome the 223 row/column limit.
 344             This extension may conflict with non UTF-8
 345             applications or non UTF-8 locales.  It is only
 346             enabled when the option `xterm-mouse-utf-8' is
 347             non-nil.
 348
 349 \"\\e[?1006h\" \"SGR coordinate extension\": Enables a newer
 350             alternative extension to the basic mouse mode, which
 351             overcomes the 223 row/column limit without the
 352             drawbacks of the UTF-8 coordinate extension.
 353
 354 The two extension modes are mutually exclusive, where the last
 355 given escape sequence takes precedence over the former."
 356   (apply #'concat (xterm-mouse--tracking-sequence ?h)))
 357
 358 (defconst xterm-mouse-tracking-enable-sequence
 359   "\e[?1000h\e[?1002h\e[?1005h\e[?1006h"
 360   "Control sequence to enable xterm mouse tracking.
 361 Enables basic mouse tracking, mouse motion events and finally
 362 extended tracking on terminals that support it. The following
 363 escape sequences are understood by modern xterms:
 364
 365 \"\\e[?1000h\" \"Basic mouse mode\": Enables reports for mouse
 366             clicks. There is a limit to the maximum row/column
 367             position (<= 223), which can be reported in this
 368             basic mode.
 369
 370 \"\\e[?1002h\" \"Mouse motion mode\": Enables reports for mouse
 371             motion events during dragging operations.
 372
 373 \"\\e[?1005h\" \"UTF-8 coordinate extension\": Enables an extension
 374             to the basic mouse mode, which uses UTF-8
 375             characters to overcome the 223 row/column limit. This
 376             extension may conflict with non UTF-8 applications or
 377             non UTF-8 locales.
 378
 379 \"\\e[?1006h\" \"SGR coordinate extension\": Enables a newer
 380             alternative extension to the basic mouse mode, which
 381             overcomes the 223 row/column limit without the
 382             drawbacks of the UTF-8 coordinate extension.
 383
 384 The two extension modes are mutually exclusive, where the last
 385 given escape sequence takes precedence over the former.")
 386
 387 (make-obsolete-variable
 388  'xterm-mouse-tracking-enable-sequence
 389  "use the function `xterm-mouse-tracking-enable-sequence' instead."
 390  "25.1")
 391
 392 (defun xterm-mouse-tracking-disable-sequence ()
 393   "Return a control sequence to disable XTerm mouse tracking.
 394 The control sequence resets the modes set by
 395 `xterm-mouse-tracking-enable-sequence'."
 396   (apply #'concat (nreverse (xterm-mouse--tracking-sequence ?l))))
 397
 398 (defconst xterm-mouse-tracking-disable-sequence
 399   "\e[?1006l\e[?1005l\e[?1002l\e[?1000l"
 400   "Reset the modes set by `xterm-mouse-tracking-enable-sequence'.")
 401
 402 (make-obsolete-variable
 403  'xterm-mouse-tracking-disable-sequence
 404  "use the function `xterm-mouse-tracking-disable-sequence' instead."
 405  "25.1")
 406
 407 (defun xterm-mouse--tracking-sequence (suffix)
 408   "Return a control sequence to enable or disable mouse tracking.
 409 SUFFIX is the last character of each escape sequence (?h to
 410 enable, ?l to disable)."
 411   (mapcar
 412    (lambda (code) (format "\e[?%d%c" code suffix))
 413    `(1000 1002 ,@(when xterm-mouse-utf-8 '(1005)) 1006)))
 414
 415 (defun turn-on-xterm-mouse-tracking-on-terminal (&optional terminal)
 416   "Enable xterm mouse tracking on TERMINAL."
 417   (when (and xterm-mouse-mode (eq t (terminal-live-p terminal))
 418              ;; Avoid the initial terminal which is not a termcap device.
 419              ;; FIXME: is there more elegant way to detect the initial
 420              ;; terminal?
 421              (not (string= (terminal-name terminal) "initial_terminal")))
 422     (unless (terminal-parameter terminal 'xterm-mouse-mode)
 423       ;; Simulate selecting a terminal by selecting one of its frames
 424       ;; so that we can set the terminal-local `input-decode-map'.
 425       (with-selected-frame (car (frames-on-display-list terminal))
 426         (define-key input-decode-map "\e[M" 'xterm-mouse-translate)
 427         (define-key input-decode-map "\e[<" 'xterm-mouse-translate-extended))
 428       (let ((enable (xterm-mouse-tracking-enable-sequence))
 429             (disable (xterm-mouse-tracking-disable-sequence)))
 430         (condition-case err
 431             (send-string-to-terminal enable terminal)
 432           ;; FIXME: This should use a dedicated error signal.
 433           (error (if (equal (cadr err) "Terminal is currently suspended")
 434                      nil ; The sequence will be sent upon resume.
 435                    (signal (car err) (cdr err)))))
 436         (push enable (terminal-parameter nil 'tty-mode-set-strings))
 437         (push disable (terminal-parameter nil 'tty-mode-reset-strings))
 438         (set-terminal-parameter terminal 'xterm-mouse-mode t)
 439         (set-terminal-parameter terminal 'xterm-mouse-utf-8
 440                                 xterm-mouse-utf-8)))))
 441
 442 (defun turn-off-xterm-mouse-tracking-on-terminal (terminal)
 443   "Disable xterm mouse tracking on TERMINAL."
 444   ;; Only send the disable command to those terminals to which we've already
 445   ;; sent the enable command.
 446   (when (and (terminal-parameter terminal 'xterm-mouse-mode)
 447              (eq t (terminal-live-p terminal)))
 448     ;; We could remove the key-binding and unset the `xterm-mouse-mode'
 449     ;; terminal parameter, but it seems less harmful to send this escape
 450     ;; command too many times (or to catch an unintended key sequence), than
 451     ;; to send it too few times (or to fail to let xterm-mouse events
 452     ;; pass by untranslated).
 453     (condition-case err
 454         (send-string-to-terminal xterm-mouse-tracking-disable-sequence
 455                                  terminal)
 456       ;; FIXME: This should use a dedicated error signal.
 457       (error (if (equal (cadr err) "Terminal is currently suspended")
 458                  nil
 459                (signal (car err) (cdr err)))))
 460     (setf (terminal-parameter nil 'tty-mode-set-strings)
 461           (remq xterm-mouse-tracking-enable-sequence
 462                 (terminal-parameter nil 'tty-mode-set-strings)))
 463     (setf (terminal-parameter nil 'tty-mode-reset-strings)
 464           (remq xterm-mouse-tracking-disable-sequence
 465                 (terminal-parameter nil 'tty-mode-reset-strings)))
 466     (set-terminal-parameter terminal 'xterm-mouse-mode nil)))
 467
 468 (provide 'xt-mouse)
 469
 470 ;;; xt-mouse.el ends here