lisp/xwidget.el

   1 ;;; xwidget.el --- api functions for xwidgets  -*- lexical-binding: t -*-
   2 ;;
   3 ;; Copyright (C) 2011-2016 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 (defcustom xwidget-webkit-scroll-behavior 'native
  38   "Scrolling behavior of the webkit instance.
  39 The possible values are: `native' or `image'."
  40   :version "25.1"
  41   :group 'frames   ; TODO add xwidgets group if more options are added
  42   :type '(choice (const native) (const image)))
  43
  44 (declare-function make-xwidget "xwidget.c"
  45                   (beg end type title width height arguments &optional buffer))
  46 (declare-function xwidget-set-adjustment "xwidget.c"
  47                   (xwidget axis relative value))
  48 (declare-function xwidget-buffer "xwidget.c" (xwidget))
  49 (declare-function xwidget-webkit-get-title "xwidget.c" (xwidget))
  50 (declare-function xwidget-size-request "xwidget.c" (xwidget))
  51 (declare-function xwidget-resize "xwidget.c" (xwidget new-width new-height))
  52 (declare-function xwidget-webkit-execute-script "xwidget.c" (xwidget script))
  53 (declare-function xwidget-webkit-goto-uri "xwidget.c" (xwidget uri))
  54 (declare-function xwidget-plist "xwidget.c" (xwidget))
  55 (declare-function set-xwidget-plist "xwidget.c" (xwidget plist))
  56 (declare-function xwidget-view-window "xwidget.c" (xwidget-view))
  57 (declare-function xwidget-view-model "xwidget.c" (xwidget-view))
  58 (declare-function delete-xwidget-view "xwidget.c" (xwidget-view))
  59 (declare-function get-buffer-xwidgets "xwidget.c" (buffer))
  60
  61 (defun xwidget-insert (pos type title width height &optional args)
  62   "Insert an xwidget at position POS.
  63 Supply the xwidget's TYPE, TITLE, WIDTH, and HEIGHT.
  64 See `make-xwidget' for the possible TYPE values.
  65 The usage of optional argument ARGS depends on the xwidget.
  66 This returns the result of `make-xwidget'."
  67   (goto-char pos)
  68   (let ((id (make-xwidget (point) (point)
  69                           type title width height args)))
  70     (put-text-property (point) (+ 1 (point))
  71                        'display (list 'xwidget ':xwidget id))
  72     id))
  73
  74 (defun xwidget-at (pos)
  75   "Return xwidget at POS."
  76   ;; TODO this function is a bit tedious because the C layer isn't well
  77   ;; protected yet and xwidgetp apparently doesn't work yet.
  78   (let* ((disp (get-text-property pos 'display))
  79          (xw (car (cdr (cdr  disp)))))
  80     ;;(if (xwidgetp  xw) xw nil)
  81     (if (equal 'xwidget (car disp)) xw)))
  82
  83
  84
  85 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  86 ;;; webkit support
  87 (require 'browse-url)
  88 (require 'image-mode);;for some image-mode alike functionality
  89
  90 ;;;###autoload
  91 (defun xwidget-webkit-browse-url (url &optional new-session)
  92   "Ask xwidget-webkit to browse URL.
  93 NEW-SESSION specifies whether to create a new xwidget-webkit session.
  94 Interactively, URL defaults to the string looking like a url around point."
  95   (interactive (progn
  96                  (require 'browse-url)
  97                  (browse-url-interactive-arg "xwidget-webkit URL: "
  98                                              ;;(xwidget-webkit-current-url)
  99                                              )))
 100   (when (stringp url)
 101     (if new-session
 102         (xwidget-webkit-new-session url)
 103       (xwidget-webkit-goto-url url))))
 104
 105 ;;todo.
 106 ;; - check that the webkit support is compiled in
 107 (defvar xwidget-webkit-mode-map
 108   (let ((map (make-sparse-keymap)))
 109     (define-key map "g" 'xwidget-webkit-browse-url)
 110     (define-key map "a" 'xwidget-webkit-adjust-size-dispatch)
 111     (define-key map "b" 'xwidget-webkit-back)
 112     (define-key map "r" 'xwidget-webkit-reload)
 113     (define-key map "t" (lambda () (interactive) (message "o"))) ;FIXME: ?!?
 114     (define-key map "\C-m" 'xwidget-webkit-insert-string)
 115     (define-key map "w" 'xwidget-webkit-current-url)
 116
 117     ;;similar to image mode bindings
 118     (define-key map (kbd "SPC")                 'xwidget-webkit-scroll-up)
 119     (define-key map (kbd "DEL")                 'xwidget-webkit-scroll-down)
 120
 121     (define-key map [remap scroll-up]           'xwidget-webkit-scroll-up)
 122     (define-key map [remap scroll-up-command]   'xwidget-webkit-scroll-up)
 123
 124     (define-key map [remap scroll-down]         'xwidget-webkit-scroll-down)
 125     (define-key map [remap scroll-down-command] 'xwidget-webkit-scroll-down)
 126
 127     (define-key map [remap forward-char]        'xwidget-webkit-scroll-forward)
 128     (define-key map [remap backward-char]       'xwidget-webkit-scroll-backward)
 129     (define-key map [remap right-char]          'xwidget-webkit-scroll-forward)
 130     (define-key map [remap left-char]           'xwidget-webkit-scroll-backward)
 131     ;; (define-key map [remap previous-line]          'image-previous-line)
 132     ;; (define-key map [remap next-line]              'image-next-line)
 133
 134     ;; (define-key map [remap move-beginning-of-line] 'image-bol)
 135     ;; (define-key map [remap move-end-of-line]       'image-eol)
 136     ;; (define-key map [remap beginning-of-buffer]    'image-bob)
 137     ;; (define-key map [remap end-of-buffer]          'image-eob)
 138     map)
 139   "Keymap for `xwidget-webkit-mode'.")
 140
 141 (defun xwidget-webkit-scroll-up ()
 142   "Scroll webkit up.
 143 Depending on the value of `xwidget-webkit-scroll-behavior',
 144 this scrolls in 'native' fashion, or like `image-mode' would."
 145   (interactive)
 146   (if (eq xwidget-webkit-scroll-behavior 'native)
 147       (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t 50)
 148     (image-scroll-up)))
 149
 150 (defun xwidget-webkit-scroll-down ()
 151   "Scroll webkit down.
 152 Depending on the value of `xwidget-webkit-scroll-behavior',
 153 this scrolls in 'native' fashion, or like `image-mode' would."
 154   (interactive)
 155   (if (eq xwidget-webkit-scroll-behavior 'native)
 156       (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t -50)
 157     (image-scroll-down)))
 158
 159 (defun xwidget-webkit-scroll-forward ()
 160   "Scroll webkit forwards.
 161 Depending on the value of `xwidget-webkit-scroll-behavior',
 162 this scrolls in 'native' fashion, or like `image-mode' would."
 163   (interactive)
 164   (if (eq xwidget-webkit-scroll-behavior 'native)
 165       (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t 50)
 166     (xwidget-webkit-scroll-forward)))   ; FIXME infloop!
 167
 168 (defun xwidget-webkit-scroll-backward ()
 169   "Scroll webkit backwards.
 170 Depending on the value of `xwidget-webkit-scroll-behavior',
 171 this scrolls in 'native' fashion, or like `image-mode' would."
 172   (interactive)
 173   (if (eq xwidget-webkit-scroll-behavior 'native)
 174       (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t -50)
 175     (xwidget-webkit-scroll-backward))) ; FIXME infloop!
 176
 177
 178 ;; The xwidget event needs to go into a higher level handler
 179 ;; since the xwidget can generate an event even if it's offscreen.
 180 ;; TODO this needs to use callbacks and consider different xwidget event types.
 181 (define-key (current-global-map) [xwidget-event] #'xwidget-event-handler)
 182 (defun xwidget-log (&rest msg)
 183   "Log MSG to a buffer."
 184   (let ((buf (get-buffer-create " *xwidget-log*")))
 185     (with-current-buffer buf
 186       (insert (apply #'format msg))
 187       (insert "\n"))))
 188
 189 (defun xwidget-event-handler ()
 190   "Receive xwidget event."
 191   (interactive)
 192   (xwidget-log "stuff happened to xwidget %S" last-input-event)
 193   (let*
 194       ((xwidget-event-type (nth 1 last-input-event))
 195        (xwidget (nth 2 last-input-event))
 196        ;;(xwidget-callback (xwidget-get xwidget 'callback))
 197        ;;TODO stopped working for some reason
 198        )
 199     ;;(funcall  xwidget-callback xwidget xwidget-event-type)
 200     (message "xw callback %s" xwidget)
 201     (funcall  'xwidget-webkit-callback xwidget xwidget-event-type)))
 202
 203 (defun xwidget-webkit-callback (xwidget xwidget-event-type)
 204   "Callback for xwidgets.
 205 XWIDGET instance, XWIDGET-EVENT-TYPE depends on the originating xwidget."
 206   (if (not (buffer-live-p (xwidget-buffer xwidget)))
 207       (xwidget-log
 208        "error: callback called for xwidget with dead buffer")
 209     (with-current-buffer (xwidget-buffer xwidget)
 210       (let* ((strarg  (nth 3 last-input-event)))
 211         (cond ((eq xwidget-event-type 'document-load-finished)
 212                (xwidget-log "webkit finished loading: '%s'"
 213                             (xwidget-webkit-get-title xwidget))
 214                ;;TODO - check the native/internal scroll
 215                ;;(xwidget-adjust-size-to-content xwidget)
 216                (xwidget-webkit-adjust-size-dispatch) ;;TODO xwidget arg
 217                (rename-buffer (format "*xwidget webkit: %s *"
 218                                       (xwidget-webkit-get-title xwidget)))
 219                (pop-to-buffer (current-buffer)))
 220               ((eq xwidget-event-type
 221                    'navigation-policy-decision-requested)
 222                (if (string-match ".*#\\(.*\\)" strarg)
 223                    (xwidget-webkit-show-id-or-named-element
 224                     xwidget
 225                     (match-string 1 strarg))))
 226               (t (xwidget-log "unhandled event:%s" xwidget-event-type)))))))
 227
 228 (defvar bookmark-make-record-function)
 229 (define-derived-mode xwidget-webkit-mode
 230     special-mode "xwidget-webkit" "Xwidget webkit view mode."
 231     (setq buffer-read-only t)
 232     (setq-local bookmark-make-record-function
 233                 #'xwidget-webkit-bookmark-make-record)
 234     ;; Keep track of [vh]scroll when switching buffers
 235     (image-mode-setup-winprops))
 236
 237 (defun xwidget-webkit-bookmark-make-record ()
 238   "Integrate Emacs bookmarks with the webkit xwidget."
 239   (nconc (bookmark-make-record-default t t)
 240          `((page     . ,(xwidget-webkit-current-url))
 241            (handler  . (lambda (bmk) (browse-url
 242                                  (bookmark-prop-get bmk 'page)))))))
 243
 244
 245 (defvar xwidget-webkit-last-session-buffer nil)
 246
 247 (defun xwidget-webkit-last-session ()
 248   "Last active webkit, or nil."
 249   (if (buffer-live-p xwidget-webkit-last-session-buffer)
 250       (with-current-buffer xwidget-webkit-last-session-buffer
 251         (xwidget-at (point-min)))
 252     nil))
 253
 254 (defun xwidget-webkit-current-session ()
 255   "Either the webkit in the current buffer, or the last one used.
 256 The latter might be nil."
 257   (or (xwidget-at (point-min)) (xwidget-webkit-last-session)))
 258
 259 (defun xwidget-adjust-size-to-content (xw)
 260   "Resize XW to content."
 261   ;; xwidgets doesn't support widgets that have their own opinions about
 262   ;; size well, yet this reads the desired size and resizes the Emacs
 263   ;; allocated area accordingly.
 264   (let ((size (xwidget-size-request xw)))
 265     (xwidget-resize xw (car size) (cadr size))))
 266
 267
 268 (defvar xwidget-webkit-activeelement-js"
 269 function findactiveelement(doc){
 270 //alert(doc.activeElement.value);
 271    if(doc.activeElement.value != undefined){
 272       return doc.activeElement;
 273    }else{
 274         // recurse over the child documents:
 275         var frames = doc.getElementsByTagName('frame');
 276         for (var i = 0; i < frames.length; i++)
 277         {
 278                 var d = frames[i].contentDocument;
 279                  var rv = findactiveelement(d);
 280                  if(rv != undefined){
 281                     return rv;
 282                  }
 283         }
 284     }
 285     return undefined;
 286 };
 287
 288
 289 "
 290
 291   "javascript that finds the active element."
 292   ;; Yes it's ugly, because:
 293   ;; - there is apparently no way to find the active frame other than recursion
 294   ;; - the js "for each" construct misbehaved on the "frames" collection
 295   ;; - a window with no frameset still has frames.length == 1, but
 296   ;; frames[0].document.activeElement != document.activeElement
 297   ;;TODO the activeelement type needs to be examined, for iframe, etc.
 298   )
 299
 300 (defun xwidget-webkit-insert-string (xw str)
 301   "Insert string STR in the active field in the webkit XW."
 302   ;; Read out the string in the field first and provide for edit.
 303   (interactive
 304    (let* ((xww (xwidget-webkit-current-session))
 305
 306           (field-value
 307            (progn
 308              (xwidget-webkit-execute-script xww xwidget-webkit-activeelement-js)
 309              (xwidget-webkit-execute-script-rv
 310               xww
 311               "findactiveelement(document).value;")))
 312           (field-type (xwidget-webkit-execute-script-rv
 313                        xww
 314                        "findactiveelement(document).type;")))
 315      (list xww
 316            (cond ((equal "text" field-type)
 317                   (read-string "Text: " field-value))
 318                  ((equal "password" field-type)
 319                   (read-passwd "Password: " nil field-value))
 320                  ((equal "textarea" field-type)
 321                   (xwidget-webkit-begin-edit-textarea xww field-value))))))
 322   (xwidget-webkit-execute-script
 323    xw
 324    (format "findactiveelement(document).value='%s'" str)))
 325
 326 (defvar xwidget-xwbl)
 327 (defun xwidget-webkit-begin-edit-textarea (xw text)
 328   "Start editing of a webkit text area.
 329 XW is the xwidget identifier, TEXT is retrieved from the webkit."
 330   (switch-to-buffer
 331    (generate-new-buffer "textarea"))
 332   (set (make-local-variable 'xwidget-xwbl) xw)
 333   (insert text))
 334
 335 (defun xwidget-webkit-end-edit-textarea ()
 336   "End editing of a webkit text area."
 337   (interactive)
 338   (goto-char (point-min))
 339   (while (search-forward "\n" nil t)
 340     (replace-match "\\n" nil t))
 341   (xwidget-webkit-execute-script
 342    xwidget-xwbl
 343    (format "findactiveelement(document).value='%s'"
 344            (buffer-substring (point-min) (point-max))))
 345   ;;TODO convert linefeed to \n
 346   )
 347
 348 (defun xwidget-webkit-show-named-element (xw element-name)
 349   "Make webkit xwidget XW show a named element ELEMENT-NAME.
 350 For example, use this to display an anchor."
 351   (interactive (list (xwidget-webkit-current-session)
 352                      (read-string "Element name: ")))
 353   ;;TODO since an xwidget is an Emacs object, it is not trivial to do
 354   ;; some things that are taken for granted in a normal browser.
 355   ;; scrolling an anchor/named-element into view is one such thing.
 356   ;; This function implements a proof-of-concept for this.  Problems
 357   ;; remaining: - The selected window is scrolled but this is not
 358   ;; always correct - This needs to be interfaced into browse-url
 359   ;; somehow.  The tricky part is that we need to do this in two steps:
 360   ;; A: load the base url, wait for load signal to arrive B: navigate
 361   ;; to the anchor when the base url is finished rendering
 362
 363   ;; This part figures out the Y coordinate of the element
 364   (let ((y (string-to-number
 365             (xwidget-webkit-execute-script-rv
 366              xw
 367              (format
 368               "document.getElementsByName('%s')[0].getBoundingClientRect().top"
 369               element-name)
 370              0))))
 371     ;; Now we need to tell Emacs to scroll the element into view.
 372     (xwidget-log "scroll: %d" y)
 373     (set-window-vscroll (selected-window) y t)))
 374
 375 (defun xwidget-webkit-show-id-element (xw element-id)
 376   "Make webkit xwidget XW show an id-element ELEMENT-ID.
 377 For example, use this to display an anchor."
 378   (interactive (list (xwidget-webkit-current-session)
 379                      (read-string "Element id: ")))
 380   (let ((y (string-to-number
 381             (xwidget-webkit-execute-script-rv
 382              xw
 383              (format "document.getElementById('%s').getBoundingClientRect().top"
 384                      element-id)
 385              0))))
 386     ;; Now we need to tell Emacs to scroll the element into view.
 387     (xwidget-log "scroll: %d" y)
 388     (set-window-vscroll (selected-window) y t)))
 389
 390 (defun xwidget-webkit-show-id-or-named-element (xw element-id)
 391    "Make webkit xwidget XW show a name or element id ELEMENT-ID.
 392 For example, use this to display an anchor."
 393   (interactive (list (xwidget-webkit-current-session)
 394                      (read-string "Name or element id: ")))
 395   (let* ((y1 (string-to-number
 396               (xwidget-webkit-execute-script-rv
 397                xw
 398                (format "document.getElementsByName('%s')[0].getBoundingClientRect().top" element-id)
 399                "0")))
 400          (y2 (string-to-number
 401               (xwidget-webkit-execute-script-rv
 402                xw
 403                (format "document.getElementById('%s').getBoundingClientRect().top" element-id)
 404                "0")))
 405          (y3 (max y1 y2)))
 406     ;; Now we need to tell Emacs to scroll the element into view.
 407     (xwidget-log "scroll: %d" y3)
 408     (set-window-vscroll (selected-window) y3 t)))
 409
 410 (defun xwidget-webkit-adjust-size-to-content ()
 411   "Adjust webkit to content size."
 412   (interactive)
 413   (xwidget-adjust-size-to-content (xwidget-webkit-current-session)))
 414
 415 (defun xwidget-webkit-adjust-size-dispatch ()
 416   "Adjust size according to mode."
 417   (interactive)
 418   (if (eq xwidget-webkit-scroll-behavior 'native)
 419       (xwidget-webkit-adjust-size-to-window)
 420     (xwidget-webkit-adjust-size-to-content))
 421   ;; The recenter is intended to correct a visual glitch.
 422   ;; It errors out if the buffer isn't visible, but then we don't get
 423   ;; the glitch, so silence errors.
 424   (ignore-errors
 425     (recenter-top-bottom)))
 426
 427 (defun xwidget-webkit-adjust-size-to-window ()
 428   "Adjust webkit to window."
 429   (interactive)
 430   (xwidget-resize (xwidget-webkit-current-session) (window-pixel-width)
 431                   (window-pixel-height)))
 432
 433 (defun xwidget-webkit-adjust-size (w h)
 434   "Manually set webkit size to width W, height H."
 435   ;; TODO shouldn't be tied to the webkit xwidget
 436   (interactive "nWidth:\nnHeight:\n")
 437   (xwidget-resize (xwidget-webkit-current-session) w h))
 438
 439 (defun xwidget-webkit-fit-width ()
 440   "Adjust width of webkit to window width."
 441   (interactive)
 442   (xwidget-webkit-adjust-size (- (nth 2 (window-inside-pixel-edges))
 443                                  (car (window-inside-pixel-edges)))
 444                               1000))
 445
 446 (defun xwidget-webkit-new-session (url)
 447   "Create a new webkit session buffer with URL."
 448   (let*
 449       ((bufname (generate-new-buffer-name "*xwidget-webkit*"))
 450        xw)
 451     (setq xwidget-webkit-last-session-buffer (switch-to-buffer
 452                                               (get-buffer-create bufname)))
 453     (insert " 'a' adjusts the xwidget size.")
 454     (setq xw (xwidget-insert 1 'webkit-osr  bufname 1000 1000))
 455     (xwidget-put xw 'callback 'xwidget-webkit-callback)
 456     (xwidget-webkit-mode)
 457     (xwidget-webkit-goto-uri (xwidget-webkit-last-session) url)))
 458
 459
 460 (defun xwidget-webkit-goto-url (url)
 461   "Goto URL."
 462   (if (xwidget-webkit-current-session)
 463       (progn
 464         (xwidget-webkit-goto-uri (xwidget-webkit-current-session) url))
 465     (xwidget-webkit-new-session url)))
 466
 467 (defun xwidget-webkit-back ()
 468   "Go back in history."
 469   (interactive)
 470   (xwidget-webkit-execute-script (xwidget-webkit-current-session)
 471                                  "history.go(-1);"))
 472
 473 (defun xwidget-webkit-reload ()
 474   "Reload current url."
 475   (interactive)
 476   (xwidget-webkit-execute-script (xwidget-webkit-current-session)
 477                                  "history.go(0);"))
 478
 479 (defun xwidget-webkit-current-url ()
 480   "Get the webkit url and place it on the kill-ring."
 481   (interactive)
 482   (let* ((rv (xwidget-webkit-execute-script-rv (xwidget-webkit-current-session)
 483                                                "document.URL"))
 484          (url (kill-new (or rv ""))))
 485     (message "url: %s" url)
 486     url))
 487
 488 (defun xwidget-webkit-execute-script-rv (xw script &optional default)
 489   "Same as `xwidget-webkit-execute-script' but with return value.
 490 XW is the webkit instance.  SCRIPT is the script to execute.
 491 DEFAULT is the default return value."
 492   ;; Notice the ugly "title" hack.  It is needed because the Webkit
 493   ;; API at the time of writing didn't support returning values.  This
 494   ;; is a wrapper for the title hack so it's easy to remove should
 495   ;; Webkit someday support JS return values or we find some other way
 496   ;; to access the DOM.
 497
 498   ;; Reset webkit title.  Not very nice.
 499   (let* ((emptytag "titlecantbewhitespaceohthehorror")
 500          title)
 501     (xwidget-webkit-execute-script xw (format "document.title=\"%s\";"
 502                                               (or default emptytag)))
 503     (xwidget-webkit-execute-script xw (format "document.title=%s;" script))
 504     (setq title (xwidget-webkit-get-title xw))
 505     (if (equal emptytag title)
 506         (setq title ""))
 507     (unless title
 508       (setq title default))
 509     title))
 510
 511 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 512 (defun xwidget-webkit-get-selection ()
 513   "Get the webkit selection."
 514   (xwidget-webkit-execute-script-rv (xwidget-webkit-current-session)
 515                                     "window.getSelection().toString();"))
 516
 517 (defun xwidget-webkit-copy-selection-as-kill ()
 518   "Get the webkit selection and put it on the kill-ring."
 519   (interactive)
 520   (kill-new (xwidget-webkit-get-selection)))
 521
 522
 523 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 524 ;; Xwidget plist management (similar to the process plist functions)
 525
 526 (defun xwidget-get (xwidget propname)
 527   "Get an xwidget's property value.
 528 XWIDGET is an xwidget, PROPNAME a property.
 529 Returns the last value stored with `xwidget-put'."
 530   (plist-get (xwidget-plist xwidget) propname))
 531
 532 (defun xwidget-put (xwidget propname value)
 533   "Set an xwidget's property value.
 534 XWIDGET is an xwidget, PROPNAME a property to be set to specified VALUE.
 535 You can retrieve the value with `xwidget-get'."
 536   (set-xwidget-plist xwidget
 537                      (plist-put (xwidget-plist xwidget) propname value)))
 538
 539
 540 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 541
 542 (defvar xwidget-view-list)              ; xwidget.c
 543 (defvar xwidget-list)                   ; xwidget.c
 544
 545 (defun xwidget-delete-zombies ()
 546   "Helper for `xwidget-cleanup'."
 547   (dolist (xwidget-view xwidget-view-list)
 548     (when (or (not (window-live-p (xwidget-view-window xwidget-view)))
 549               (not (memq (xwidget-view-model xwidget-view)
 550                          xwidget-list)))
 551       (delete-xwidget-view xwidget-view))))
 552
 553 (defun xwidget-cleanup ()
 554   "Delete zombie xwidgets."
 555   ;; During development it was sometimes easy to wind up with zombie
 556   ;; xwidget instances.
 557   ;; This function tries to implement a workaround should it occur again.
 558   (interactive)
 559   ;; Kill xviews that should have been deleted but still linger.
 560   (xwidget-delete-zombies)
 561   ;; Redraw display otherwise ghost of zombies will remain to haunt the screen
 562   (redraw-display))
 563
 564 (defun xwidget-kill-buffer-query-function ()
 565   "Ask before killing a buffer that has xwidgets."
 566   (let ((xwidgets (get-buffer-xwidgets (current-buffer))))
 567     (or (not xwidgets)
 568         (not (memq t (mapcar #'xwidget-query-on-exit-flag xwidgets)))
 569         (yes-or-no-p
 570          (format "Buffer %S has xwidgets; kill it? " (buffer-name))))))
 571
 572 (when (featurep 'xwidget-internal)
 573   (add-hook 'kill-buffer-query-functions #'xwidget-kill-buffer-query-function)
 574   ;; This would have felt better in C, but this seems to work well in
 575   ;; practice though.
 576   (add-hook 'window-configuration-change-hook #'xwidget-delete-zombies))
 577
 578 (provide 'xwidget)
 579 ;;; xwidget.el ends here