lisp/xwidget.el

   1 ;;; xwidget.el --- api functions for xwidgets  -*- lexical-binding: t -*-
   2 ;;
   3 ;; Copyright (C) 2011-2017 Free Software Foundation, Inc.
   4 ;;
   5 ;; Author: Joakim Verona (joakim@verona.se)
   6 ;;
   7 ;; This file is part of GNU Emacs.
   8 ;;
   9 ;; GNU Emacs is free software: you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation, either version 3 of the License, or
  12 ;; (at your option) any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  21 ;;
  22 ;; --------------------------------------------------------------------
  23
  24 ;;; Commentary:
  25 ;;
  26 ;; See xwidget.c for more api functions.
  27
  28 ;; This breaks compilation when we don't have xwidgets.
  29 ;; And is pointless when we do, since it's in C and so preloaded.
  30 ;;(require 'xwidget-internal)
  31
  32 ;;; Code:
  33
  34 (require 'cl-lib)
  35 (require 'bookmark)
  36
  37 (declare-function make-xwidget "xwidget.c"
  38                   (type title width height arguments &optional buffer))
  39 (declare-function xwidget-set-adjustment "xwidget.c"
  40                   (xwidget axis relative value))
  41 (declare-function xwidget-buffer "xwidget.c" (xwidget))
  42 (declare-function xwidget-webkit-get-title "xwidget.c" (xwidget))
  43 (declare-function xwidget-size-request "xwidget.c" (xwidget))
  44 (declare-function xwidget-resize "xwidget.c" (xwidget new-width new-height))
  45 (declare-function xwidget-webkit-execute-script "xwidget.c" (xwidget script))
  46 (declare-function xwidget-webkit-goto-uri "xwidget.c" (xwidget uri))
  47 (declare-function xwidget-plist "xwidget.c" (xwidget))
  48 (declare-function set-xwidget-plist "xwidget.c" (xwidget plist))
  49 (declare-function xwidget-view-window "xwidget.c" (xwidget-view))
  50 (declare-function xwidget-view-model "xwidget.c" (xwidget-view))
  51 (declare-function delete-xwidget-view "xwidget.c" (xwidget-view))
  52 (declare-function get-buffer-xwidgets "xwidget.c" (buffer))
  53 (declare-function xwidget-query-on-exit-flag "xwidget.c" (xwidget))
  54
  55 (defun xwidget-insert (pos type title width height &optional args)
  56   "Insert an xwidget at position POS.
  57 Supply the xwidget's TYPE, TITLE, WIDTH, and HEIGHT.
  58 See `make-xwidget' for the possible TYPE values.
  59 The usage of optional argument ARGS depends on the xwidget.
  60 This returns the result of `make-xwidget'."
  61   (goto-char pos)
  62   (let ((id (make-xwidget type title width height args)))
  63     (put-text-property (point) (+ 1 (point))
  64                        'display (list 'xwidget ':xwidget id))
  65     id))
  66
  67 (defun xwidget-at (pos)
  68   "Return xwidget at POS."
  69   ;; TODO this function is a bit tedious because the C layer isn't well
  70   ;; protected yet and xwidgetp apparently doesn't work yet.
  71   (let* ((disp (get-text-property pos 'display))
  72          (xw (car (cdr (cdr  disp)))))
  73     ;;(if (xwidgetp  xw) xw nil)
  74     (if (equal 'xwidget (car disp)) xw)))
  75
  76
  77
  78 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  79 ;;; webkit support
  80 (require 'browse-url)
  81 (require 'image-mode);;for some image-mode alike functionality
  82
  83 ;;;###autoload
  84 (defun xwidget-webkit-browse-url (url &optional new-session)
  85   "Ask xwidget-webkit to browse URL.
  86 NEW-SESSION specifies whether to create a new xwidget-webkit session.
  87 Interactively, URL defaults to the string looking like a url around point."
  88   (interactive (progn
  89                  (require 'browse-url)
  90                  (browse-url-interactive-arg "xwidget-webkit URL: "
  91                                              ;;(xwidget-webkit-current-url)
  92                                              )))
  93   (or (featurep 'xwidget-internal)
  94       (user-error "Your Emacs was not compiled with xwidgets support"))
  95   (when (stringp url)
  96     (if new-session
  97         (xwidget-webkit-new-session url)
  98       (xwidget-webkit-goto-url url))))
  99
 100 ;;todo.
 101 ;; - check that the webkit support is compiled in
 102 (defvar xwidget-webkit-mode-map
 103   (let ((map (make-sparse-keymap)))
 104     (define-key map "g" 'xwidget-webkit-browse-url)
 105     (define-key map "a" 'xwidget-webkit-adjust-size-dispatch)
 106     (define-key map "b" 'xwidget-webkit-back)
 107     (define-key map "r" 'xwidget-webkit-reload)
 108     (define-key map "t" (lambda () (interactive) (message "o"))) ;FIXME: ?!?
 109     (define-key map "\C-m" 'xwidget-webkit-insert-string)
 110     (define-key map "w" 'xwidget-webkit-current-url)
 111
 112     ;;similar to image mode bindings
 113     (define-key map (kbd "SPC")                 'xwidget-webkit-scroll-up)
 114     (define-key map (kbd "DEL")                 'xwidget-webkit-scroll-down)
 115
 116     (define-key map [remap scroll-up]           'xwidget-webkit-scroll-up)
 117     (define-key map [remap scroll-up-command]   'xwidget-webkit-scroll-up)
 118
 119     (define-key map [remap scroll-down]         'xwidget-webkit-scroll-down)
 120     (define-key map [remap scroll-down-command] 'xwidget-webkit-scroll-down)
 121
 122     (define-key map [remap forward-char]        'xwidget-webkit-scroll-forward)
 123     (define-key map [remap backward-char]       'xwidget-webkit-scroll-backward)
 124     (define-key map [remap right-char]          'xwidget-webkit-scroll-forward)
 125     (define-key map [remap left-char]           'xwidget-webkit-scroll-backward)
 126     ;; (define-key map [remap previous-line]          'image-previous-line)
 127     ;; (define-key map [remap next-line]              'image-next-line)
 128
 129     ;; (define-key map [remap move-beginning-of-line] 'image-bol)
 130     ;; (define-key map [remap move-end-of-line]       'image-eol)
 131     ;; (define-key map [remap beginning-of-buffer]    'image-bob)
 132     ;; (define-key map [remap end-of-buffer]          'image-eob)
 133     map)
 134   "Keymap for `xwidget-webkit-mode'.")
 135
 136 (defun xwidget-webkit-scroll-up ()
 137   "Scroll webkit up."
 138   (interactive)
 139   (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t 50))
 140
 141 (defun xwidget-webkit-scroll-down ()
 142   "Scroll webkit down."
 143   (interactive)
 144   (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t -50))
 145
 146 (defun xwidget-webkit-scroll-forward ()
 147   "Scroll webkit forwards."
 148   (interactive)
 149   (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t 50))
 150
 151 (defun xwidget-webkit-scroll-backward ()
 152   "Scroll webkit backwards."
 153   (interactive)
 154   (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t -50))
 155
 156
 157 ;; The xwidget event needs to go into a higher level handler
 158 ;; since the xwidget can generate an event even if it's offscreen.
 159 ;; TODO this needs to use callbacks and consider different xwidget event types.
 160 (define-key (current-global-map) [xwidget-event] #'xwidget-event-handler)
 161 (defun xwidget-log (&rest msg)
 162   "Log MSG to a buffer."
 163   (let ((buf (get-buffer-create " *xwidget-log*")))
 164     (with-current-buffer buf
 165       (insert (apply #'format msg))
 166       (insert "\n"))))
 167
 168 (defun xwidget-event-handler ()
 169   "Receive xwidget event."
 170   (interactive)
 171   (xwidget-log "stuff happened to xwidget %S" last-input-event)
 172   (let*
 173       ((xwidget-event-type (nth 1 last-input-event))
 174        (xwidget (nth 2 last-input-event))
 175        ;;(xwidget-callback (xwidget-get xwidget 'callback))
 176        ;;TODO stopped working for some reason
 177        )
 178     ;;(funcall  xwidget-callback xwidget xwidget-event-type)
 179     (message "xw callback %s" xwidget)
 180     (funcall  'xwidget-webkit-callback xwidget xwidget-event-type)))
 181
 182 (defun xwidget-webkit-callback (xwidget xwidget-event-type)
 183   "Callback for xwidgets.
 184 XWIDGET instance, XWIDGET-EVENT-TYPE depends on the originating xwidget."
 185   (if (not (buffer-live-p (xwidget-buffer xwidget)))
 186       (xwidget-log
 187        "error: callback called for xwidget with dead buffer")
 188     (with-current-buffer (xwidget-buffer xwidget)
 189       (let* ((strarg  (nth 3 last-input-event)))
 190         (cond ((eq xwidget-event-type 'document-load-finished)
 191                (xwidget-log "webkit finished loading: '%s'"
 192                             (xwidget-webkit-get-title xwidget))
 193                ;;TODO - check the native/internal scroll
 194                ;;(xwidget-adjust-size-to-content xwidget)
 195                (xwidget-webkit-adjust-size-dispatch) ;;TODO xwidget arg
 196                (rename-buffer (format "*xwidget webkit: %s *"
 197                                       (xwidget-webkit-get-title xwidget)))
 198                (pop-to-buffer (current-buffer)))
 199               ((eq xwidget-event-type
 200                    'navigation-policy-decision-requested)
 201                (if (string-match ".*#\\(.*\\)" strarg)
 202                    (xwidget-webkit-show-id-or-named-element
 203                     xwidget
 204                     (match-string 1 strarg))))
 205               (t (xwidget-log "unhandled event:%s" xwidget-event-type)))))))
 206
 207 (defvar bookmark-make-record-function)
 208 (define-derived-mode xwidget-webkit-mode
 209     special-mode "xwidget-webkit" "Xwidget webkit view mode."
 210     (setq buffer-read-only t)
 211     (setq-local bookmark-make-record-function
 212                 #'xwidget-webkit-bookmark-make-record)
 213     ;; Keep track of [vh]scroll when switching buffers
 214     (image-mode-setup-winprops))
 215
 216 (defun xwidget-webkit-bookmark-make-record ()
 217   "Integrate Emacs bookmarks with the webkit xwidget."
 218   (nconc (bookmark-make-record-default t t)
 219          `((page     . ,(xwidget-webkit-current-url))
 220            (handler  . (lambda (bmk) (browse-url
 221                                  (bookmark-prop-get bmk 'page)))))))
 222
 223
 224 (defvar xwidget-webkit-last-session-buffer nil)
 225
 226 (defun xwidget-webkit-last-session ()
 227   "Last active webkit, or nil."
 228   (if (buffer-live-p xwidget-webkit-last-session-buffer)
 229       (with-current-buffer xwidget-webkit-last-session-buffer
 230         (xwidget-at (point-min)))
 231     nil))
 232
 233 (defun xwidget-webkit-current-session ()
 234   "Either the webkit in the current buffer, or the last one used.
 235 The latter might be nil."
 236   (or (xwidget-at (point-min)) (xwidget-webkit-last-session)))
 237
 238 (defun xwidget-adjust-size-to-content (xw)
 239   "Resize XW to content."
 240   ;; xwidgets doesn't support widgets that have their own opinions about
 241   ;; size well, yet this reads the desired size and resizes the Emacs
 242   ;; allocated area accordingly.
 243   (let ((size (xwidget-size-request xw)))
 244     (xwidget-resize xw (car size) (cadr size))))
 245
 246
 247 (defvar xwidget-webkit-activeelement-js"
 248 function findactiveelement(doc){
 249 //alert(doc.activeElement.value);
 250    if(doc.activeElement.value != undefined){
 251       return doc.activeElement;
 252    }else{
 253         // recurse over the child documents:
 254         var frames = doc.getElementsByTagName('frame');
 255         for (var i = 0; i < frames.length; i++)
 256         {
 257                 var d = frames[i].contentDocument;
 258                  var rv = findactiveelement(d);
 259                  if(rv != undefined){
 260                     return rv;
 261                  }
 262         }
 263     }
 264     return undefined;
 265 };
 266
 267
 268 "
 269
 270   "javascript that finds the active element."
 271   ;; Yes it's ugly, because:
 272   ;; - there is apparently no way to find the active frame other than recursion
 273   ;; - the js "for each" construct misbehaved on the "frames" collection
 274   ;; - a window with no frameset still has frames.length == 1, but
 275   ;; frames[0].document.activeElement != document.activeElement
 276   ;;TODO the activeelement type needs to be examined, for iframe, etc.
 277   )
 278
 279 (defun xwidget-webkit-insert-string (xw str)
 280   "Insert string STR in the active field in the webkit XW."
 281   ;; Read out the string in the field first and provide for edit.
 282   (interactive
 283    (let* ((xww (xwidget-webkit-current-session))
 284
 285           (field-value
 286            (progn
 287              (xwidget-webkit-execute-script xww xwidget-webkit-activeelement-js)
 288              (xwidget-webkit-execute-script-rv
 289               xww
 290               "findactiveelement(document).value;")))
 291           (field-type (xwidget-webkit-execute-script-rv
 292                        xww
 293                        "findactiveelement(document).type;")))
 294      (list xww
 295            (cond ((equal "text" field-type)
 296                   (read-string "Text: " field-value))
 297                  ((equal "password" field-type)
 298                   (read-passwd "Password: " nil field-value))
 299                  ((equal "textarea" field-type)
 300                   (xwidget-webkit-begin-edit-textarea xww field-value))))))
 301   (xwidget-webkit-execute-script
 302    xw
 303    (format "findactiveelement(document).value='%s'" str)))
 304
 305 (defvar xwidget-xwbl)
 306 (defun xwidget-webkit-begin-edit-textarea (xw text)
 307   "Start editing of a webkit text area.
 308 XW is the xwidget identifier, TEXT is retrieved from the webkit."
 309   (switch-to-buffer
 310    (generate-new-buffer "textarea"))
 311   (set (make-local-variable 'xwidget-xwbl) xw)
 312   (insert text))
 313
 314 (defun xwidget-webkit-end-edit-textarea ()
 315   "End editing of a webkit text area."
 316   (interactive)
 317   (goto-char (point-min))
 318   (while (search-forward "\n" nil t)
 319     (replace-match "\\n" nil t))
 320   (xwidget-webkit-execute-script
 321    xwidget-xwbl
 322    (format "findactiveelement(document).value='%s'"
 323            (buffer-substring (point-min) (point-max))))
 324   ;;TODO convert linefeed to \n
 325   )
 326
 327 (defun xwidget-webkit-show-named-element (xw element-name)
 328   "Make webkit xwidget XW show a named element ELEMENT-NAME.
 329 For example, use this to display an anchor."
 330   (interactive (list (xwidget-webkit-current-session)
 331                      (read-string "Element name: ")))
 332   ;;TODO since an xwidget is an Emacs object, it is not trivial to do
 333   ;; some things that are taken for granted in a normal browser.
 334   ;; scrolling an anchor/named-element into view is one such thing.
 335   ;; This function implements a proof-of-concept for this.  Problems
 336   ;; remaining: - The selected window is scrolled but this is not
 337   ;; always correct - This needs to be interfaced into browse-url
 338   ;; somehow.  The tricky part is that we need to do this in two steps:
 339   ;; A: load the base url, wait for load signal to arrive B: navigate
 340   ;; to the anchor when the base url is finished rendering
 341
 342   ;; This part figures out the Y coordinate of the element
 343   (let ((y (string-to-number
 344             (xwidget-webkit-execute-script-rv
 345              xw
 346              (format
 347               "document.getElementsByName('%s')[0].getBoundingClientRect().top"
 348               element-name)
 349              0))))
 350     ;; Now we need to tell Emacs to scroll the element into view.
 351     (xwidget-log "scroll: %d" y)
 352     (set-window-vscroll (selected-window) y t)))
 353
 354 (defun xwidget-webkit-show-id-element (xw element-id)
 355   "Make webkit xwidget XW show an id-element ELEMENT-ID.
 356 For example, use this to display an anchor."
 357   (interactive (list (xwidget-webkit-current-session)
 358                      (read-string "Element id: ")))
 359   (let ((y (string-to-number
 360             (xwidget-webkit-execute-script-rv
 361              xw
 362              (format "document.getElementById('%s').getBoundingClientRect().top"
 363                      element-id)
 364              0))))
 365     ;; Now we need to tell Emacs to scroll the element into view.
 366     (xwidget-log "scroll: %d" y)
 367     (set-window-vscroll (selected-window) y t)))
 368
 369 (defun xwidget-webkit-show-id-or-named-element (xw element-id)
 370    "Make webkit xwidget XW show a name or element id ELEMENT-ID.
 371 For example, use this to display an anchor."
 372   (interactive (list (xwidget-webkit-current-session)
 373                      (read-string "Name or element id: ")))
 374   (let* ((y1 (string-to-number
 375               (xwidget-webkit-execute-script-rv
 376                xw
 377                (format "document.getElementsByName('%s')[0].getBoundingClientRect().top" element-id)
 378                "0")))
 379          (y2 (string-to-number
 380               (xwidget-webkit-execute-script-rv
 381                xw
 382                (format "document.getElementById('%s').getBoundingClientRect().top" element-id)
 383                "0")))
 384          (y3 (max y1 y2)))
 385     ;; Now we need to tell Emacs to scroll the element into view.
 386     (xwidget-log "scroll: %d" y3)
 387     (set-window-vscroll (selected-window) y3 t)))
 388
 389 (defun xwidget-webkit-adjust-size-to-content ()
 390   "Adjust webkit to content size."
 391   (interactive)
 392   (xwidget-adjust-size-to-content (xwidget-webkit-current-session)))
 393
 394 (defun xwidget-webkit-adjust-size-dispatch ()
 395   "Adjust size according to mode."
 396   (interactive)
 397   (xwidget-webkit-adjust-size-to-window)
 398   ;; The recenter is intended to correct a visual glitch.
 399   ;; It errors out if the buffer isn't visible, but then we don't get
 400   ;; the glitch, so silence errors.
 401   (ignore-errors
 402     (recenter-top-bottom)))
 403
 404 (defun xwidget-webkit-adjust-size-to-window ()
 405   "Adjust webkit to window."
 406   (interactive)
 407   (xwidget-resize (xwidget-webkit-current-session) (window-pixel-width)
 408                   (window-pixel-height)))
 409
 410 (defun xwidget-webkit-adjust-size (w h)
 411   "Manually set webkit size to width W, height H."
 412   ;; TODO shouldn't be tied to the webkit xwidget
 413   (interactive "nWidth:\nnHeight:\n")
 414   (xwidget-resize (xwidget-webkit-current-session) w h))
 415
 416 (defun xwidget-webkit-fit-width ()
 417   "Adjust width of webkit to window width."
 418   (interactive)
 419   (xwidget-webkit-adjust-size (- (nth 2 (window-inside-pixel-edges))
 420                                  (car (window-inside-pixel-edges)))
 421                               1000))
 422
 423 (defun xwidget-webkit-new-session (url)
 424   "Create a new webkit session buffer with URL."
 425   (let*
 426       ((bufname (generate-new-buffer-name "*xwidget-webkit*"))
 427        xw)
 428     (setq xwidget-webkit-last-session-buffer (switch-to-buffer
 429                                               (get-buffer-create bufname)))
 430     (insert " 'a' adjusts the xwidget size.")
 431     (setq xw (xwidget-insert 1 'webkit  bufname 1000 1000))
 432     (xwidget-put xw 'callback 'xwidget-webkit-callback)
 433     (xwidget-webkit-mode)
 434     (xwidget-webkit-goto-uri (xwidget-webkit-last-session) url)))
 435
 436
 437 (defun xwidget-webkit-goto-url (url)
 438   "Goto URL."
 439   (if (xwidget-webkit-current-session)
 440       (progn
 441         (xwidget-webkit-goto-uri (xwidget-webkit-current-session) url))
 442     (xwidget-webkit-new-session url)))
 443
 444 (defun xwidget-webkit-back ()
 445   "Go back in history."
 446   (interactive)
 447   (xwidget-webkit-execute-script (xwidget-webkit-current-session)
 448                                  "history.go(-1);"))
 449
 450 (defun xwidget-webkit-reload ()
 451   "Reload current url."
 452   (interactive)
 453   (xwidget-webkit-execute-script (xwidget-webkit-current-session)
 454                                  "history.go(0);"))
 455
 456 (defun xwidget-webkit-current-url ()
 457   "Get the webkit url and place it on the kill-ring."
 458   (interactive)
 459   (let* ((rv (xwidget-webkit-execute-script-rv (xwidget-webkit-current-session)
 460                                                "document.URL"))
 461          (url (kill-new (or rv ""))))
 462     (message "url: %s" url)
 463     url))
 464
 465 (defun xwidget-webkit-execute-script-rv (xw script &optional default)
 466   "Same as `xwidget-webkit-execute-script' but with return value.
 467 XW is the webkit instance.  SCRIPT is the script to execute.
 468 DEFAULT is the default return value."
 469   ;; Notice the ugly "title" hack.  It is needed because the Webkit
 470   ;; API at the time of writing didn't support returning values.  This
 471   ;; is a wrapper for the title hack so it's easy to remove should
 472   ;; Webkit someday support JS return values or we find some other way
 473   ;; to access the DOM.
 474
 475   ;; Reset webkit title.  Not very nice.
 476   (let* ((emptytag "titlecantbewhitespaceohthehorror")
 477          title)
 478     (xwidget-webkit-execute-script xw (format "document.title=\"%s\";"
 479                                               (or default emptytag)))
 480     (xwidget-webkit-execute-script xw (format "document.title=%s;" script))
 481     (setq title (xwidget-webkit-get-title xw))
 482     (if (equal emptytag title)
 483         (setq title ""))
 484     (unless title
 485       (setq title default))
 486     title))
 487
 488 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 489 (defun xwidget-webkit-get-selection ()
 490   "Get the webkit selection."
 491   (xwidget-webkit-execute-script-rv (xwidget-webkit-current-session)
 492                                     "window.getSelection().toString();"))
 493
 494 (defun xwidget-webkit-copy-selection-as-kill ()
 495   "Get the webkit selection and put it on the kill-ring."
 496   (interactive)
 497   (kill-new (xwidget-webkit-get-selection)))
 498
 499
 500 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 501 ;; Xwidget plist management (similar to the process plist functions)
 502
 503 (defun xwidget-get (xwidget propname)
 504   "Get an xwidget's property value.
 505 XWIDGET is an xwidget, PROPNAME a property.
 506 Returns the last value stored with `xwidget-put'."
 507   (plist-get (xwidget-plist xwidget) propname))
 508
 509 (defun xwidget-put (xwidget propname value)
 510   "Set an xwidget's property value.
 511 XWIDGET is an xwidget, PROPNAME a property to be set to specified VALUE.
 512 You can retrieve the value with `xwidget-get'."
 513   (set-xwidget-plist xwidget
 514                      (plist-put (xwidget-plist xwidget) propname value)))
 515
 516
 517 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 518
 519 (defvar xwidget-view-list)              ; xwidget.c
 520 (defvar xwidget-list)                   ; xwidget.c
 521
 522 (defun xwidget-delete-zombies ()
 523   "Helper for `xwidget-cleanup'."
 524   (dolist (xwidget-view xwidget-view-list)
 525     (when (or (not (window-live-p (xwidget-view-window xwidget-view)))
 526               (not (memq (xwidget-view-model xwidget-view)
 527                          xwidget-list)))
 528       (delete-xwidget-view xwidget-view))))
 529
 530 (defun xwidget-cleanup ()
 531   "Delete zombie xwidgets."
 532   ;; During development it was sometimes easy to wind up with zombie
 533   ;; xwidget instances.
 534   ;; This function tries to implement a workaround should it occur again.
 535   (interactive)
 536   ;; Kill xviews that should have been deleted but still linger.
 537   (xwidget-delete-zombies)
 538   ;; Redraw display otherwise ghost of zombies will remain to haunt the screen
 539   (redraw-display))
 540
 541 (defun xwidget-kill-buffer-query-function ()
 542   "Ask before killing a buffer that has xwidgets."
 543   (let ((xwidgets (get-buffer-xwidgets (current-buffer))))
 544     (or (not xwidgets)
 545         (not (memq t (mapcar #'xwidget-query-on-exit-flag xwidgets)))
 546         (yes-or-no-p
 547          (format "Buffer %S has xwidgets; kill it? " (buffer-name))))))
 548
 549 (when (featurep 'xwidget-internal)
 550   (add-hook 'kill-buffer-query-functions #'xwidget-kill-buffer-query-function)
 551   ;; This would have felt better in C, but this seems to work well in
 552   ;; practice though.
 553   (add-hook 'window-configuration-change-hook #'xwidget-delete-zombies))
 554
 555 (provide 'xwidget)
 556 ;;; xwidget.el ends here