lisp/x-dnd.el

   1 ;;; x-dnd.el --- drag and drop support for X.
   2
   3 ;; Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
   4
   5 ;; Author: Jan Dj\e,Ad\e(Brv <jan.h.d@swipnet.se>
   6 ;; Maintainer: FSF
   7 ;; Keywords: window, drag, drop
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; This file provides the drop part only.  Currently supported protocols
  27 ;; are XDND, Motif and the old KDE 1.x protocol.
  28
  29 ;;; Code:
  30
  31 (require 'dnd)
  32
  33 ;;; Customizable variables
  34 (defcustom x-dnd-test-function 'x-dnd-default-test-function
  35   "The function drag and drop uses to determine if to accept or reject a drop.
  36 The function takes three arguments, WINDOW, ACTION and TYPES.
  37 WINDOW is where the mouse is when the function is called.  WINDOW may be a
  38 frame if the mouse isn't over a real window (i.e. menu bar, tool bar or
  39 scroll bar).  ACTION is the suggested action from the drag and drop source,
  40 one of the symbols move, copy, link or ask.  TYPES is a list of available
  41 types for the drop.
  42
  43 The function shall return nil to reject the drop or a cons with two values,
  44 the wanted action as car and the wanted type as cdr.  The wanted action
  45 can be copy, move, link, ask or private.
  46 The default value for this variable is `x-dnd-default-test-function'."
  47   :version "22.1"
  48   :type 'symbol
  49   :group 'x)
  50
  51
  52
  53 (defcustom x-dnd-types-alist
  54   '(
  55     ("text/uri-list" . x-dnd-handle-uri-list)
  56     ("text/x-moz-url" . x-dnd-handle-moz-url)
  57     ("_NETSCAPE_URL" . x-dnd-handle-uri-list)
  58     ("FILE_NAME" . x-dnd-handle-file-name)
  59     ("UTF8_STRING" . x-dnd-insert-utf8-text)
  60     ("text/plain;charset=UTF-8" . x-dnd-insert-utf8-text)
  61     ("text/plain;charset=utf-8" . x-dnd-insert-utf8-text)
  62     ("text/unicode" . x-dnd-insert-utf16-text)
  63     ("text/plain" . dnd-insert-text)
  64     ("COMPOUND_TEXT" . x-dnd-insert-ctext)
  65     ("STRING" . dnd-insert-text)
  66     ("TEXT"   . dnd-insert-text)
  67     )
  68   "Which function to call to handle a drop of that type.
  69 If the type for the drop is not present, or the function is nil,
  70 the drop is rejected.  The function takes three arguments, WINDOW, ACTION
  71 and DATA.  WINDOW is where the drop occurred, ACTION is the action for
  72 this drop (copy, move, link, private or ask) as determined by a previous
  73 call to `x-dnd-test-function'.  DATA is the drop data.
  74 The function shall return the action used (copy, move, link or private)
  75 if drop is successful, nil if not."
  76   :version "22.1"
  77   :type 'alist
  78   :group 'x)
  79
  80 (defcustom x-dnd-known-types
  81   '("text/uri-list"
  82     "text/x-moz-url"
  83     "_NETSCAPE_URL"
  84     "FILE_NAME"
  85     "UTF8_STRING"
  86     "text/plain;charset=UTF-8"
  87     "text/plain;charset=utf-8"
  88     "text/unicode"
  89     "text/plain"
  90     "COMPOUND_TEXT"
  91     "STRING"
  92     "TEXT"
  93     )
  94   "The types accepted by default for dropped data.
  95 The types are chosen in the order they appear in the list."
  96   :version "22.1"
  97   :type '(repeat string)
  98   :group 'x
  99 )
 100
 101 ;; Internal variables
 102
 103 (defvar x-dnd-current-state nil
 104   "The current state for a drop.
 105 This is an alist with one entry for each display.  The value for each display
 106 is a vector that contains the state for drag and drop for that display.
 107 Elements in the vector are:
 108 Last buffer drag was in,
 109 last window drag was in,
 110 types available for drop,
 111 the action suggested by the source,
 112 the type we want for the drop,
 113 the action we want for the drop,
 114 any protocol specific data.")
 115
 116 (defvar x-dnd-empty-state [nil nil nil nil nil nil nil])
 117
 118 (declare-function x-register-dnd-atom "xselect.c")
 119
 120 (defun x-dnd-init-frame (&optional frame)
 121   "Setup drag and drop for FRAME (i.e. create appropriate properties)."
 122   (when (eq 'x (window-system frame))
 123     (x-register-dnd-atom "DndProtocol" frame)
 124     (x-register-dnd-atom "_MOTIF_DRAG_AND_DROP_MESSAGE" frame)
 125     (x-register-dnd-atom "XdndEnter" frame)
 126     (x-register-dnd-atom "XdndPosition" frame)
 127     (x-register-dnd-atom "XdndLeave" frame)
 128     (x-register-dnd-atom "XdndDrop" frame)
 129     (x-dnd-init-xdnd-for-frame frame)
 130     (x-dnd-init-motif-for-frame frame)))
 131
 132 (defun x-dnd-get-state-cons-for-frame (frame-or-window)
 133   "Return the entry in `x-dnd-current-state' for a frame or window."
 134   (let* ((frame (if (framep frame-or-window) frame-or-window
 135                   (window-frame frame-or-window)))
 136          (display (frame-parameter frame 'display)))
 137     (if (not (assoc display x-dnd-current-state))
 138         (push (cons display (copy-sequence x-dnd-empty-state))
 139               x-dnd-current-state))
 140     (assoc display x-dnd-current-state)))
 141
 142 (defun x-dnd-get-state-for-frame (frame-or-window)
 143   "Return the state in `x-dnd-current-state' for a frame or window."
 144   (cdr (x-dnd-get-state-cons-for-frame frame-or-window)))
 145
 146 (defun x-dnd-default-test-function (window action types)
 147   "The default test function for drag and drop.
 148 WINDOW is where the mouse is when this function is called.  It may be
 149 a frame if the mouse is over the menu bar, scroll bar or tool bar.
 150 ACTION is the suggested action from the source, and TYPES are the
 151 types the drop data can have.  This function only accepts drops with
 152 types in `x-dnd-known-types'.  It always returns the action private."
 153   (let ((type (x-dnd-choose-type types)))
 154     (when type (cons 'private type))))
 155
 156
 157 (defun x-dnd-current-type (frame-or-window)
 158   "Return the type we want the DND data to be in for the current drop.
 159 FRAME-OR-WINDOW is the frame or window that the mouse is over."
 160   (aref (x-dnd-get-state-for-frame frame-or-window) 4))
 161
 162 (defun x-dnd-forget-drop (frame-or-window)
 163   "Remove all state for the last drop.
 164 FRAME-OR-WINDOW is the frame or window that the mouse is over."
 165   (setcdr (x-dnd-get-state-cons-for-frame frame-or-window)
 166           (copy-sequence x-dnd-empty-state)))
 167
 168 (defun x-dnd-maybe-call-test-function (window action)
 169   "Call `x-dnd-test-function' if something has changed.
 170 WINDOW is the window the mouse is over.  ACTION is the suggested
 171 action from the source.  If nothing has changed, return the last
 172 action and type we got from `x-dnd-test-function'."
 173   (let ((buffer (when (window-live-p window)
 174                   (window-buffer window)))
 175         (current-state (x-dnd-get-state-for-frame window)))
 176     (when (or (not (equal buffer (aref current-state 0)))
 177               (not (equal window (aref current-state 1)))
 178               (not (equal action (aref current-state 3))))
 179       (save-excursion
 180         (when buffer (set-buffer buffer))
 181         (let* ((action-type (funcall x-dnd-test-function
 182                                      window
 183                                      action
 184                                      (aref current-state 2)))
 185                (handler (cdr (assoc (cdr action-type) x-dnd-types-alist))))
 186           ;; Ignore action-type if we have no handler.
 187           (setq current-state
 188                 (x-dnd-save-state window
 189                                   action
 190                                   (when handler action-type)))))))
 191   (let ((current-state (x-dnd-get-state-for-frame window)))
 192     (cons (aref current-state 5)
 193           (aref current-state 4))))
 194
 195 (defun x-dnd-save-state (window action action-type &optional types extra-data)
 196   "Save the state of the current drag and drop.
 197 WINDOW is the window the mouse is over.  ACTION is the action suggested
 198 by the source.  ACTION-TYPE is the result of calling `x-dnd-test-function'.
 199 If given, TYPES are the types for the drop data that the source supports.
 200 EXTRA-DATA is data needed for a specific protocol."
 201   (let ((current-state (x-dnd-get-state-for-frame window)))
 202     (aset current-state 5 (car action-type))
 203     (aset current-state 4 (cdr action-type))
 204     (aset current-state 3 action)
 205     (when types (aset current-state 2 types))
 206     (when extra-data (aset current-state 6 extra-data))
 207     (aset current-state 1 window)
 208     (aset current-state 0 (and (window-live-p window) (window-buffer window)))
 209     (setcdr (x-dnd-get-state-cons-for-frame window) current-state)))
 210
 211
 212 (defun x-dnd-handle-moz-url (window action data)
 213   "Handle one item of type text/x-moz-url.
 214 WINDOW is the window where the drop happened.  ACTION is ignored.
 215 DATA is the moz-url, which is formatted as two strings separated by \\r\\n.
 216 The first string is the URL, the second string is the title of that URL.
 217 DATA is encoded in utf-16.  Decode the URL and call `x-dnd-handle-uri-list'."
 218   ;; Mozilla and applications based on it (Galeon for example) uses
 219   ;; text/unicode, but it is impossible to tell if it is le or be.  Use what
 220   ;; the machine Emacs runs on use.  This looses if dropping between machines
 221   ;; with different endian, but it is the best we can do.
 222   (let* ((coding (if (eq (byteorder) ?B) 'utf-16be 'utf-16le))
 223          (string (decode-coding-string data coding))
 224          (strings (split-string string "[\r\n]" t))
 225          ;; Can one drop more than one moz-url ??  Assume not.
 226          (url (car strings))
 227          (title (car (cdr strings))))
 228     (x-dnd-handle-uri-list window action url)))
 229
 230 (defun x-dnd-insert-utf8-text (window action text)
 231   "Decode the UTF-8 text and insert it at point.
 232 TEXT is the text as a string, WINDOW is the window where the drop happened."
 233   (dnd-insert-text window action (decode-coding-string text 'utf-8)))
 234
 235 (defun x-dnd-insert-utf16-text (window action text)
 236   "Decode the UTF-16 text and insert it at point.
 237 TEXT is the text as a string, WINDOW is the window where the drop happened."
 238   ;; See comment in x-dnd-handle-moz-url about coding.
 239   (let ((coding (if (eq (byteorder) ?B) 'utf-16be 'utf-16le)))
 240     (dnd-insert-text window action (decode-coding-string text coding))))
 241
 242 (defun x-dnd-insert-ctext (window action text)
 243   "Decode the compound text and insert it at point.
 244 TEXT is the text as a string, WINDOW is the window where the drop happened."
 245   (dnd-insert-text window action
 246                    (decode-coding-string text
 247                                          'compound-text-with-extensions)))
 248
 249 (defun x-dnd-handle-uri-list (window action string)
 250   "Split an uri-list into separate URIs and call `dnd-handle-one-url'.
 251 WINDOW is the window where the drop happened.
 252 STRING is the uri-list as a string.  The URIs are separated by \\r\\n."
 253   (let ((uri-list (split-string string "[\0\r\n]" t))
 254         retval)
 255     (dolist (bf uri-list)
 256       ;; If one URL is handled, treat as if the whole drop succeeded.
 257       (let ((did-action (dnd-handle-one-url window action bf)))
 258         (when did-action (setq retval did-action))))
 259     retval))
 260
 261 (defun x-dnd-handle-file-name (window action string)
 262   "Convert file names to URLs and call `dnd-handle-one-url'.
 263 WINDOW is the window where the drop happened.
 264 STRING is the file names as a string, separated by nulls."
 265   (let ((uri-list (split-string string "[\0\r\n]" t))
 266         (coding (and default-enable-multibyte-characters
 267                      (or file-name-coding-system
 268                          default-file-name-coding-system)))
 269         retval)
 270     (dolist (bf uri-list)
 271       ;; If one URL is handled, treat as if the whole drop succeeded.
 272       (if coding (setq bf (encode-coding-string bf coding)))
 273       (let* ((file-uri (concat "file://"
 274                                (mapconcat 'url-hexify-string
 275                                           (split-string bf "/") "/")))
 276              (did-action (dnd-handle-one-url window action file-uri)))
 277         (when did-action (setq retval did-action))))
 278     retval))
 279
 280
 281 (defun x-dnd-choose-type (types &optional known-types)
 282   "Choose which type we want to receive for the drop.
 283 TYPES are the types the source of the drop offers, a vector of type names
 284 as strings or symbols.  Select among the types in `x-dnd-known-types' or
 285 KNOWN-TYPES if given, and return that type name.
 286 If no suitable type is found, return nil."
 287   (let* ((known-list (or known-types x-dnd-known-types))
 288          (first-known-type (car known-list))
 289          (types-array types)
 290          (found (when first-known-type
 291                   (catch 'done
 292                     (dotimes (i (length types-array))
 293                       (let* ((type (aref types-array i))
 294                              (typename (if (symbolp type)
 295                                            (symbol-name type) type)))
 296                         (when (equal first-known-type typename)
 297                           (throw 'done first-known-type))))
 298                     nil))))
 299
 300     (if (and (not found) (cdr known-list))
 301         (x-dnd-choose-type types (cdr known-list))
 302       found)))
 303
 304 (defun x-dnd-drop-data (event frame window data type)
 305   "Drop one data item onto a frame.
 306 EVENT is the client message for the drop, FRAME is the frame the drop
 307 occurred on.  WINDOW is the window of FRAME where the drop happened.
 308 DATA is the data received from the source, and type is the type for DATA,
 309 see `x-dnd-types-alist').
 310
 311 Returns the action used (move, copy, link, private) if drop was successful,
 312 nil if not."
 313   (let* ((type-info (assoc type x-dnd-types-alist))
 314          (handler (cdr type-info))
 315          (state (x-dnd-get-state-for-frame frame))
 316          (action (aref state 5))
 317          (w (posn-window (event-start event))))
 318     (when handler
 319       (if (and (window-live-p w)
 320                (not (window-minibuffer-p w))
 321                (not (window-dedicated-p w)))
 322           ;; If dropping in an ordinary window which we could use,
 323           ;; let dnd-open-file-other-window specify what to do.
 324           (progn
 325             (when (not mouse-yank-at-point)
 326               (goto-char (posn-point (event-start event))))
 327             (funcall handler window action data))
 328         ;; If we can't display the file here,
 329         ;; make a new window for it.
 330         (let ((dnd-open-file-other-window t))
 331           (select-frame frame)
 332           (funcall handler window action data))))))
 333
 334 (defun x-dnd-handle-drag-n-drop-event (event)
 335   "Receive drag and drop events (X client messages).
 336 Currently XDND, Motif and old KDE 1.x protocols are recognized."
 337   (interactive "e")
 338   (let* ((client-message (car (cdr (cdr event))))
 339          (window (posn-window (event-start event)))
 340          (message-atom (aref client-message 0))
 341          (frame (aref client-message 1))
 342          (format (aref client-message 2))
 343          (data (aref client-message 3)))
 344
 345     (cond ((equal "DndProtocol" message-atom)   ; Old KDE 1.x.
 346            (x-dnd-handle-old-kde event frame window message-atom format data))
 347
 348           ((equal "_MOTIF_DRAG_AND_DROP_MESSAGE" message-atom)  ; Motif
 349            (x-dnd-handle-motif event frame window message-atom format data))
 350
 351           ((and (> (length message-atom) 4)     ; XDND protocol.
 352                 (equal "Xdnd" (substring message-atom 0 4)))
 353            (x-dnd-handle-xdnd event frame window message-atom format data)))))
 354
 355
 356 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 357 ;;;  Old KDE protocol.  Only dropping of files.
 358
 359 (declare-function x-window-property "xfns.c"
 360                   (prop &optional frame type source delete-p vector-ret-p))
 361
 362 (defun x-dnd-handle-old-kde (event frame window message format data)
 363   "Open the files in a KDE 1.x drop."
 364   (let ((values (x-window-property "DndSelection" frame nil 0 t)))
 365     (x-dnd-handle-uri-list window 'private
 366                            (replace-regexp-in-string "\0$" "" values))))
 367 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 368
 369
 370
 371 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 372 ;;;  XDND protocol.
 373
 374 (defvar x-dnd-xdnd-to-action
 375   '(("XdndActionPrivate" . private)
 376     ("XdndActionCopy" . copy)
 377     ("XdndActionMove" . move)
 378     ("XdndActionLink" . link)
 379     ("XdndActionAsk" . ask))
 380   "Mapping from XDND action types to lisp symbols.")
 381
 382 (declare-function x-change-window-property "xfns.c"
 383                   (prop value &optional frame type format outer-P))
 384
 385 (defun x-dnd-init-xdnd-for-frame (frame)
 386   "Set the XdndAware property for FRAME to indicate that we do XDND."
 387   (x-change-window-property "XdndAware"
 388                             '(5)        ;; The version of XDND we support.
 389                             frame "ATOM" 32 t))
 390
 391 (defun x-dnd-get-drop-width-height (frame w accept)
 392   "Return the width/height to be sent in a XDndStatus message.
 393 FRAME is the frame and W is the window where the drop happened.
 394 If ACCEPT is nil return 0 (empty rectangle),
 395 otherwise if W is a window, return its width/height,
 396 otherwise return the frame width/height."
 397   (if accept
 398       (if (windowp w)   ;; w is not a window if dropping on the menu bar,
 399                         ;; scroll bar or tool bar.
 400           (let ((edges (window-inside-pixel-edges w)))
 401             (cons
 402              (- (nth 2 edges) (nth 0 edges))    ;; right - left
 403              (- (nth 3 edges) (nth 1 edges))))  ;; bottom - top
 404         (cons (frame-pixel-width frame)
 405               (frame-pixel-height frame)))
 406     0))
 407
 408 (defun x-dnd-get-drop-x-y (frame w)
 409   "Return the x/y coordinates to be sent in a XDndStatus message.
 410 Coordinates are required to be absolute.
 411 FRAME is the frame and W is the window where the drop happened.
 412 If W is a window, return its absolute corrdinates,
 413 otherwise return the frame coordinates."
 414   (let* ((frame-left (frame-parameter frame 'left))
 415          ;; If the frame is outside the display, frame-left looks like
 416          ;; '(0 -16).  Extract the -16.
 417          (frame-real-left (if (consp frame-left) (car (cdr frame-left))
 418                             frame-left))
 419          (frame-top (frame-parameter frame 'top))
 420          (frame-real-top (if (consp frame-top) (car (cdr frame-top))
 421                            frame-top)))
 422     (if (windowp w)
 423         (let ((edges (window-inside-pixel-edges w)))
 424           (cons
 425            (+ frame-real-left (nth 0 edges))
 426            (+ frame-real-top (nth 1 edges))))
 427       (cons frame-real-left frame-real-top))))
 428
 429 (declare-function x-get-atom-name "xselect.c" (value &optional frame))
 430 (declare-function x-send-client-message "xselect.c"
 431                   (display dest from message-type format values))
 432 (declare-function x-get-selection-internal "xselect.c"
 433                   (selection-symbol target-type &optional time-stamp))
 434
 435 (defun x-dnd-handle-xdnd (event frame window message format data)
 436   "Receive one XDND event (client message) and send the appropriate reply.
 437 EVENT is the client message.  FRAME is where the mouse is now.
 438 WINDOW is the window within FRAME where the mouse is now.
 439 FORMAT is 32 (not used).  MESSAGE is the data part of an XClientMessageEvent."
 440   (cond ((equal "XdndEnter" message)
 441          (let* ((flags (aref data 1))
 442                 (version (and (consp flags) (ash (car flags) -8)))
 443                 (more-than-3 (and (consp flags) (cdr flags)))
 444                 (dnd-source (aref data 0)))
 445            (if version  ;; If flags is bad, version will be nil.
 446                (x-dnd-save-state
 447                 window nil nil
 448                 (if (> more-than-3 0)
 449                     (x-window-property "XdndTypeList"
 450                                        frame "AnyPropertyType"
 451                                        dnd-source nil t)
 452                   (vector (x-get-atom-name (aref data 2))
 453                           (x-get-atom-name (aref data 3))
 454                           (x-get-atom-name (aref data 4))))))))
 455
 456         ((equal "XdndPosition" message)
 457          (let* ((x (car (aref data 2)))
 458                 (y (cdr (aref data 2)))
 459                 (action (x-get-atom-name (aref data 4)))
 460                 (dnd-source (aref data 0))
 461                 (dnd-time (aref data 3))
 462                 (action-type (x-dnd-maybe-call-test-function
 463                               window
 464                               (cdr (assoc action x-dnd-xdnd-to-action))))
 465                 (reply-action (car (rassoc (car action-type)
 466                                            x-dnd-xdnd-to-action)))
 467                 (accept ;; 1 = accept, 0 = reject
 468                  (if (and reply-action action-type) 1 0))
 469                 (list-to-send
 470                  (list (string-to-number
 471                         (frame-parameter frame 'outer-window-id))
 472                        accept ;; 1 = Accept, 0 = reject.
 473                        (x-dnd-get-drop-x-y frame window)
 474                        (x-dnd-get-drop-width-height
 475                         frame window (eq accept 1))
 476                        (or reply-action 0)
 477                        )))
 478            (x-send-client-message
 479             frame dnd-source frame "XdndStatus" 32 list-to-send)
 480            ))
 481
 482         ((equal "XdndLeave" message)
 483          (x-dnd-forget-drop window))
 484
 485         ((equal "XdndDrop" message)
 486          (if (windowp window) (select-window window))
 487          (let* ((dnd-source (aref data 0))
 488                 (value (and (x-dnd-current-type window)
 489                             (x-get-selection-internal
 490                              'XdndSelection
 491                              (intern (x-dnd-current-type window)))))
 492                 success action ret-action)
 493
 494            (setq action (if value
 495                             (condition-case info
 496                                 (x-dnd-drop-data event frame window value
 497                                                  (x-dnd-current-type window))
 498                               (error
 499                                (message "Error: %s" info)
 500                                nil))))
 501
 502            (setq success (if action 1 0))
 503            (setq ret-action
 504                  (if (eq success 1)
 505                      (or (car (rassoc action x-dnd-xdnd-to-action))
 506                          "XdndActionPrivate")
 507                    0))
 508
 509            (x-send-client-message
 510             frame dnd-source frame "XdndFinished" 32
 511             (list (string-to-number (frame-parameter frame 'outer-window-id))
 512                   success       ;; 1 = Success, 0 = Error
 513                   (if success "XdndActionPrivate" 0)
 514                   ))
 515            (x-dnd-forget-drop window)))
 516
 517         (t (error "Unknown XDND message %s %s" message data))))
 518
 519 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 520 ;;;  Motif protocol.
 521
 522 (defun x-dnd-init-motif-for-frame (frame)
 523   "Set _MOTIF_DRAG_RECEIVER_INFO for FRAME to indicate that we do Motif DND."
 524   (x-change-window-property "_MOTIF_DRAG_RECEIVER_INFO"
 525                             (list
 526                              (byteorder)
 527                              0                  ; The Motif DND version.
 528                              5                  ; We want drag dynamic.
 529                              0 0 0 0 0 0 0
 530                              0 0 0 0 0 0)       ; Property must be 16 bytes.
 531                             frame "_MOTIF_DRAG_RECEIVER_INFO" 8 t))
 532
 533 (defun x-dnd-get-motif-value (data offset size byteorder)
 534   (cond ((eq size 2)
 535          (if (eq byteorder ?l)
 536              (+ (ash (aref data (1+ offset)) 8)
 537                 (aref data offset))
 538            (+ (ash (aref data offset) 8)
 539               (aref data (1+ offset)))))
 540
 541         ((eq size 4)
 542          (if (eq byteorder ?l)
 543              (cons (+ (ash (aref data (+ 3 offset)) 8)
 544                       (aref data (+ 2 offset)))
 545                    (+ (ash (aref data (1+ offset)) 8)
 546                       (aref data offset)))
 547            (cons (+ (ash (aref data offset) 8)
 548                     (aref data (1+ offset)))
 549                  (+ (ash (aref data (+ 2 offset)) 8)
 550                     (aref data (+ 3 offset))))))))
 551
 552 (defun x-dnd-motif-value-to-list (value size byteorder)
 553   (let ((bytes (cond ((eq size 2)
 554                       (list (logand (lsh value -8) ?\xff)
 555                             (logand value ?\xff)))
 556
 557                      ((eq size 4)
 558                       (if (consp value)
 559                           (list (logand (lsh (car value) -8) ?\xff)
 560                                 (logand (car value) ?\xff)
 561                                 (logand (lsh (cdr value) -8) ?\xff)
 562                                 (logand (cdr value) ?\xff))
 563                         (list (logand (lsh value -24) ?\xff)
 564                               (logand (lsh value -16) ?\xff)
 565                               (logand (lsh value -8) ?\xff)
 566                               (logand value ?\xff)))))))
 567     (if (eq byteorder ?l)
 568         (reverse bytes)
 569       bytes)))
 570
 571
 572 (defvar x-dnd-motif-message-types
 573   '((0 . XmTOP_LEVEL_ENTER)
 574     (1 . XmTOP_LEVEL_LEAVE)
 575     (2 . XmDRAG_MOTION)
 576     (3 . XmDROP_SITE_ENTER)
 577     (4 . XmDROP_SITE_LEAVE)
 578     (5 . XmDROP_START)
 579     (6 . XmDROP_FINISH)
 580     (7 . XmDRAG_DROP_FINISH)
 581     (8 . XmOPERATION_CHANGED))
 582   "Mapping from numbers to Motif DND message types.")
 583
 584 (defvar x-dnd-motif-to-action
 585   '((1 . move)
 586     (2 . copy)
 587     (3 . link)  ; Both 3 and 4 has been seen as link.
 588     (4 . link)
 589     (2 . private)) ; Motif does not have private, so use copy for private.
 590   "Mapping from number to operation for Motif DND.")
 591
 592 (defun x-dnd-handle-motif (event frame window message-atom format data)
 593   (let* ((message-type (cdr (assoc (aref data 0) x-dnd-motif-message-types)))
 594          (source-byteorder (aref data 1))
 595          (my-byteorder (byteorder))
 596          (source-flags (x-dnd-get-motif-value data 2 2 source-byteorder))
 597          (source-action (cdr (assoc (logand ?\xF source-flags)
 598                                     x-dnd-motif-to-action))))
 599
 600     (cond ((eq message-type 'XmTOP_LEVEL_ENTER)
 601            (let* ((dnd-source (x-dnd-get-motif-value
 602                                data 8 4 source-byteorder))
 603                   (selection-atom (x-dnd-get-motif-value
 604                                    data 12 4 source-byteorder))
 605                   (atom-name (x-get-atom-name selection-atom))
 606                   (types (when atom-name
 607                            (x-get-selection-internal (intern atom-name)
 608                                                      'TARGETS))))
 609              (x-dnd-forget-drop frame)
 610              (when types (x-dnd-save-state window nil nil
 611                                            types
 612                                            dnd-source))))
 613
 614           ;; Can not forget drop here, LEAVE comes before DROP_START and
 615           ;; we need the state in DROP_START.
 616           ((eq message-type 'XmTOP_LEVEL_LEAVE)
 617            nil)
 618
 619           ((eq message-type 'XmDRAG_MOTION)
 620            (let* ((state (x-dnd-get-state-for-frame frame))
 621                   (timestamp (x-dnd-motif-value-to-list
 622                               (x-dnd-get-motif-value data 4 4
 623                                                      source-byteorder)
 624                               4 my-byteorder))
 625                   (x (x-dnd-motif-value-to-list
 626                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 627                       2 my-byteorder))
 628                   (y (x-dnd-motif-value-to-list
 629                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 630                       2 my-byteorder))
 631                   (dnd-source (aref state 6))
 632                   (first-move (not (aref state 3)))
 633                   (action-type (x-dnd-maybe-call-test-function
 634                                 window
 635                                 source-action))
 636                   (reply-action (car (rassoc (car action-type)
 637                                              x-dnd-motif-to-action)))
 638                   (reply-flags
 639                    (x-dnd-motif-value-to-list
 640                     (if reply-action
 641                         (+ reply-action
 642                            ?\x30        ; 30:  valid drop site
 643                            ?\x700)      ; 700: can do copy, move or link
 644                       ?\x30)            ; 30:  drop site, but noop.
 645                     2 my-byteorder))
 646                   (reply (append
 647                           (list
 648                            (+ ?\x80     ; 0x80 indicates a reply.
 649                               (if first-move
 650                                   3     ; First time, reply is SITE_ENTER.
 651                                 2))     ; Not first time, reply is DRAG_MOTION.
 652                            my-byteorder)
 653                           reply-flags
 654                           timestamp
 655                           x
 656                           y)))
 657              (x-send-client-message frame
 658                                     dnd-source
 659                                     frame
 660                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 661                                     8
 662                                     reply)))
 663
 664           ((eq message-type 'XmOPERATION_CHANGED)
 665            (let* ((state (x-dnd-get-state-for-frame frame))
 666                   (timestamp (x-dnd-motif-value-to-list
 667                               (x-dnd-get-motif-value data 4 4 source-byteorder)
 668                               4 my-byteorder))
 669                   (dnd-source (aref state 6))
 670                   (action-type (x-dnd-maybe-call-test-function
 671                                 window
 672                                 source-action))
 673                   (reply-action (car (rassoc (car action-type)
 674                                              x-dnd-motif-to-action)))
 675                   (reply-flags
 676                    (x-dnd-motif-value-to-list
 677                     (if reply-action
 678                         (+ reply-action
 679                            ?\x30        ; 30:  valid drop site
 680                            ?\x700)      ; 700: can do copy, move or link
 681                       ?\x30)            ; 30:  drop site, but noop
 682                     2 my-byteorder))
 683                   (reply (append
 684                           (list
 685                            (+ ?\x80     ; 0x80 indicates a reply.
 686                               8)        ; 8 is OPERATION_CHANGED
 687                            my-byteorder)
 688                           reply-flags
 689                           timestamp)))
 690              (x-send-client-message frame
 691                                     dnd-source
 692                                     frame
 693                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 694                                     8
 695                                     reply)))
 696
 697           ((eq message-type 'XmDROP_START)
 698            (let* ((x (x-dnd-motif-value-to-list
 699                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 700                       2 my-byteorder))
 701                   (y (x-dnd-motif-value-to-list
 702                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 703                       2 my-byteorder))
 704                   (selection-atom (x-dnd-get-motif-value
 705                                    data 12 4 source-byteorder))
 706                   (atom-name (x-get-atom-name selection-atom))
 707                   (dnd-source (x-dnd-get-motif-value
 708                                data 16 4 source-byteorder))
 709                   (action-type (x-dnd-maybe-call-test-function
 710                                 window
 711                                 source-action))
 712                   (reply-action (car (rassoc (car action-type)
 713                                              x-dnd-motif-to-action)))
 714                   (reply-flags
 715                    (x-dnd-motif-value-to-list
 716                     (if reply-action
 717                         (+ reply-action
 718                            ?\x30        ; 30:  valid drop site
 719                            ?\x700)      ; 700: can do copy, move or link
 720                       (+ ?\x30          ; 30:  drop site, but noop.
 721                          ?\x200))       ; 200: drop cancel.
 722                     2 my-byteorder))
 723                   (reply (append
 724                           (list
 725                            (+ ?\x80     ; 0x80 indicates a reply.
 726                               5)        ; DROP_START.
 727                            my-byteorder)
 728                           reply-flags
 729                           x
 730                           y))
 731                   (timestamp (x-dnd-get-motif-value
 732                               data 4 4 source-byteorder))
 733                   action)
 734
 735              (x-send-client-message frame
 736                                     dnd-source
 737                                     frame
 738                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 739                                     8
 740                                     reply)
 741              (setq action
 742                    (when (and reply-action atom-name)
 743                      (let* ((value (x-get-selection-internal
 744                                     (intern atom-name)
 745                                     (intern (x-dnd-current-type window)))))
 746                        (when value
 747                          (condition-case info
 748                              (x-dnd-drop-data event frame window value
 749                                               (x-dnd-current-type window))
 750                            (error
 751                             (message "Error: %s" info)
 752                             nil))))))
 753              (x-get-selection-internal
 754               (intern atom-name)
 755               (if action 'XmTRANSFER_SUCCESS 'XmTRANSFER_FAILURE)
 756               timestamp)
 757              (x-dnd-forget-drop frame)))
 758
 759           (t (error "Unknown Motif DND message %s %s" message-atom data)))))
 760
 761
 762 ;;;
 763
 764 (provide 'x-dnd)
 765
 766 ;; arch-tag: b621fb7e-50da-4323-850b-5fc71ae64621
 767 ;;; x-dnd.el ends here