lisp/x-dnd.el

   1 ;;; x-dnd.el --- drag and drop support for X.
   2
   3 ;; Copyright (C) 2004, 2005, 2006, 2007, 2008 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, or (at your option)
  14 ;; 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; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This file provides the drop part only.  Currently supported protocols
  29 ;; are XDND, Motif and the old KDE 1.x protocol.
  30
  31 ;;; Code:
  32
  33 (require 'dnd)
  34
  35 ;;; Customizable variables
  36 (defcustom x-dnd-test-function 'x-dnd-default-test-function
  37   "The function drag and drop uses to determine if to accept or reject a drop.
  38 The function takes three arguments, WINDOW ACTION and TYPES.
  39 WINDOW is where the mouse is when the function is called.  WINDOW may be a
  40 frame if the mouse isn't over a real window (i.e. menu bar, tool bar or
  41 scroll bar).  ACTION is the suggested action from the drag and drop source,
  42 one of the symbols move, copy link or ask.  TYPES is a list of available types
  43 for the drop.
  44
  45 The function shall return nil to reject the drop or a cons with two values,
  46 the wanted action as car and the wanted type as cdr.  The wanted action
  47 can be copy, move, link, ask or private.
  48 The default value for this variable is `x-dnd-default-test-function'."
  49   :version "22.1"
  50   :type 'symbol
  51   :group 'x)
  52
  53
  54
  55 (defcustom x-dnd-types-alist
  56   '(
  57     ("text/uri-list" . x-dnd-handle-uri-list)
  58     ("text/x-moz-url" . x-dnd-handle-moz-url)
  59     ("_NETSCAPE_URL" . x-dnd-handle-uri-list)
  60     ("FILE_NAME" . x-dnd-handle-file-name)
  61     ("UTF8_STRING" . x-dnd-insert-utf8-text)
  62     ("text/plain;charset=UTF-8" . x-dnd-insert-utf8-text)
  63     ("text/plain;charset=utf-8" . x-dnd-insert-utf8-text)
  64     ("text/unicode" . x-dnd-insert-utf16-text)
  65     ("text/plain" . dnd-insert-text)
  66     ("COMPOUND_TEXT" . x-dnd-insert-ctext)
  67     ("STRING" . dnd-insert-text)
  68     ("TEXT"   . dnd-insert-text)
  69     )
  70   "Which function to call to handle a drop of that type.
  71 If the type for the drop is not present, or the function is nil,
  72 the drop is rejected.  The function takes three arguments, WINDOW, ACTION
  73 and DATA.  WINDOW is where the drop occurred, ACTION is the action for
  74 this drop (copy, move, link, private or ask) as determined by a previous
  75 call to `x-dnd-test-function'.  DATA is the drop data.
  76 The function shall return the action used (copy, move, link or private) if drop
  77 is successful, nil if not."
  78   :version "22.1"
  79   :type 'alist
  80   :group 'x)
  81
  82 (defcustom x-dnd-known-types
  83   '("text/uri-list"
  84     "text/x-moz-url"
  85     "_NETSCAPE_URL"
  86     "FILE_NAME"
  87     "UTF8_STRING"
  88     "text/plain;charset=UTF-8"
  89     "text/plain;charset=utf-8"
  90     "text/unicode"
  91     "text/plain"
  92     "COMPOUND_TEXT"
  93     "STRING"
  94     "TEXT"
  95     )
  96   "The types accepted by default for dropped data.
  97 The types are chosen in the order they appear in the list."
  98   :version "22.1"
  99   :type '(repeat string)
 100   :group 'x
 101 )
 102
 103 ;; Internal variables
 104
 105 (defvar x-dnd-current-state nil
 106   "The current state for a drop.
 107 This is an alist with one entry for each display.  The value for each display
 108 is a vector that contains the state for drag and drop for that display.
 109 Elements in the vector are:
 110 Last buffer drag was in,
 111 last window drag was in,
 112 types available for drop,
 113 the action suggested by the source,
 114 the type we want for the drop,
 115 the action we want for the drop,
 116 any protocol specific data.")
 117
 118 (defvar x-dnd-empty-state [nil nil nil nil nil nil nil])
 119
 120 (declare-function x-register-dnd-atom "xselect.c")
 121
 122 (defun x-dnd-init-frame (&optional frame)
 123   "Setup drag and drop for FRAME (i.e. create appropriate properties)."
 124   (when (eq 'x (window-system frame))
 125     (x-register-dnd-atom "DndProtocol" frame)
 126     (x-register-dnd-atom "_MOTIF_DRAG_AND_DROP_MESSAGE" frame)
 127     (x-register-dnd-atom "XdndEnter" frame)
 128     (x-register-dnd-atom "XdndPosition" frame)
 129     (x-register-dnd-atom "XdndLeave" frame)
 130     (x-register-dnd-atom "XdndDrop" frame)
 131     (x-dnd-init-xdnd-for-frame frame)
 132     (x-dnd-init-motif-for-frame frame)))
 133
 134 (defun x-dnd-get-state-cons-for-frame (frame-or-window)
 135   "Return the entry in x-dnd-current-state for a frame or window."
 136   (let* ((frame (if (framep frame-or-window) frame-or-window
 137                   (window-frame frame-or-window)))
 138          (display (frame-parameter frame 'display)))
 139     (if (not (assoc display x-dnd-current-state))
 140         (push (cons display (copy-sequence x-dnd-empty-state))
 141               x-dnd-current-state))
 142     (assoc display x-dnd-current-state)))
 143
 144 (defun x-dnd-get-state-for-frame (frame-or-window)
 145   "Return the state in x-dnd-current-state for a frame or window."
 146   (cdr (x-dnd-get-state-cons-for-frame frame-or-window)))
 147
 148 (defun x-dnd-default-test-function (window action types)
 149   "The default test function for drag and drop.
 150 WINDOW is where the mouse is when this function is called.  It may be a frame
 151 if the mouse is over the menu bar, scroll bar or tool bar.
 152 ACTION is the suggested action from the source, and TYPES are the
 153 types the drop data can have.  This function only accepts drops with
 154 types in `x-dnd-known-types'.  It always returns the action private."
 155   (let ((type (x-dnd-choose-type types)))
 156     (when type (cons 'private type))))
 157
 158
 159 (defun x-dnd-current-type (frame-or-window)
 160   "Return the type we want the DND data to be in for the current drop.
 161 FRAME-OR-WINDOW is the frame or window that the mouse is over."
 162   (aref (x-dnd-get-state-for-frame frame-or-window) 4))
 163
 164 (defun x-dnd-forget-drop (frame-or-window)
 165   "Remove all state for the last drop.
 166 FRAME-OR-WINDOW is the frame or window that the mouse is over."
 167   (setcdr (x-dnd-get-state-cons-for-frame frame-or-window)
 168           (copy-sequence x-dnd-empty-state)))
 169
 170 (defun x-dnd-maybe-call-test-function (window action)
 171   "Call `x-dnd-test-function' if something has changed.
 172 WINDOW is the window the mouse is over.  ACTION is the suggested
 173 action from the source.  If nothing has changed, return the last
 174 action and type we got from `x-dnd-test-function'."
 175   (let ((buffer (when (window-live-p window)
 176                   (window-buffer window)))
 177         (current-state (x-dnd-get-state-for-frame window)))
 178     (when (or (not (equal buffer (aref current-state 0)))
 179               (not (equal window (aref current-state 1)))
 180               (not (equal action (aref current-state 3))))
 181       (save-excursion
 182         (when buffer (set-buffer buffer))
 183         (let* ((action-type (funcall x-dnd-test-function
 184                                      window
 185                                      action
 186                                      (aref current-state 2)))
 187                (handler (cdr (assoc (cdr action-type) x-dnd-types-alist))))
 188           ;; Ignore action-type if we have no handler.
 189           (setq current-state
 190                 (x-dnd-save-state window
 191                                   action
 192                                   (when handler action-type)))))))
 193   (let ((current-state (x-dnd-get-state-for-frame window)))
 194     (cons (aref current-state 5)
 195           (aref current-state 4))))
 196
 197 (defun x-dnd-save-state (window action action-type &optional types extra-data)
 198   "Save the state of the current drag and drop.
 199 WINDOW is the window the mouse is over.  ACTION is the action suggested
 200 by the source.  ACTION-TYPE is the result of calling `x-dnd-test-function'.
 201 If given, TYPES are the types for the drop data that the source supports.
 202 EXTRA-DATA is data needed for a specific protocol."
 203   (let ((current-state (x-dnd-get-state-for-frame window)))
 204     (aset current-state 5 (car action-type))
 205     (aset current-state 4 (cdr action-type))
 206     (aset current-state 3 action)
 207     (when types (aset current-state 2 types))
 208     (when extra-data (aset current-state 6 extra-data))
 209     (aset current-state 1 window)
 210     (aset current-state 0 (and (window-live-p window) (window-buffer window)))
 211     (setcdr (x-dnd-get-state-cons-for-frame window) current-state)))
 212
 213
 214 (defun x-dnd-handle-moz-url (window action data)
 215   "Handle one item of type text/x-moz-url.
 216 WINDOW is the window where the drop happened.  ACTION is ignored.
 217 DATA is the moz-url, which is formatted as two strings separated by \r\n.
 218 The first string is the URL, the second string is the title of that URL.
 219 DATA is encoded in utf-16.  Decode the URL and call `x-dnd-handle-uri-list'."
 220   ;; Mozilla and applications based on it (Galeon for example) uses
 221   ;; text/unicode, but it is impossible to tell if it is le or be.  Use what
 222   ;; the machine Emacs runs on use.  This looses if dropping between machines
 223   ;; with different endian, but it is the best we can do.
 224   (let* ((coding (if (eq (byteorder) ?B) 'utf-16be 'utf-16le))
 225          (string (decode-coding-string data coding))
 226          (strings (split-string string "[\r\n]" t))
 227          ;; Can one drop more than one moz-url ??  Assume not.
 228          (url (car strings))
 229          (title (car (cdr strings))))
 230     (x-dnd-handle-uri-list window action url)))
 231
 232 (defun x-dnd-insert-utf8-text (window action text)
 233   "Decode the UTF-8 text and insert it at point.
 234 TEXT is the text as a string, WINDOW is the window where the drop happened."
 235   (dnd-insert-text window action (decode-coding-string text 'utf-8)))
 236
 237 (defun x-dnd-insert-utf16-text (window action text)
 238   "Decode the UTF-16 text and insert it at point.
 239 TEXT is the text as a string, WINDOW is the window where the drop happened."
 240   ;; See comment in x-dnd-handle-moz-url about coding.
 241   (let ((coding (if (eq (byteorder) ?B) 'utf-16be 'utf-16le)))
 242     (dnd-insert-text window action (decode-coding-string text coding))))
 243
 244 (defun x-dnd-insert-ctext (window action text)
 245   "Decode the compound text and insert it at point.
 246 TEXT is the text as a string, WINDOW is the window where the drop happened."
 247   (dnd-insert-text window action
 248                    (decode-coding-string text
 249                                          'compound-text-with-extensions)))
 250
 251 (defun x-dnd-handle-uri-list (window action string)
 252   "Split an uri-list into separate URIs and call `dnd-handle-one-url'.
 253 WINDOW is the window where the drop happened.
 254 STRING is the uri-list as a string.  The URIs are separated by \r\n."
 255   (let ((uri-list (split-string string "[\0\r\n]" t))
 256         retval)
 257     (dolist (bf uri-list)
 258       ;; If one URL is handeled, treat as if the whole drop succeeded.
 259       (let ((did-action (dnd-handle-one-url window action bf)))
 260         (when did-action (setq retval did-action))))
 261     retval))
 262
 263 (defun x-dnd-handle-file-name (window action string)
 264   "Convert file names to URLs and call `dnd-handle-one-url'.
 265 WINDOW is the window where the drop happened.
 266 STRING is the file names as a string, separated by nulls."
 267   (let ((uri-list (split-string string "[\0\r\n]" t))
 268         (coding (and default-enable-multibyte-characters
 269                      (or file-name-coding-system
 270                          default-file-name-coding-system)))
 271         retval)
 272     (dolist (bf uri-list)
 273       ;; If one URL is handeled, treat as if the whole drop succeeded.
 274       (if coding (setq bf (encode-coding-string bf coding)))
 275       (let* ((file-uri (concat "file://"
 276                                (mapconcat 'url-hexify-string
 277                                           (split-string bf "/") "/")))
 278              (did-action (dnd-handle-one-url window action file-uri)))
 279         (when did-action (setq retval did-action))))
 280     retval))
 281
 282
 283 (defun x-dnd-choose-type (types &optional known-types)
 284   "Choose which type we want to receive for the drop.
 285 TYPES are the types the source of the drop offers, a vector of type names
 286 as strings or symbols.  Select among the types in `x-dnd-known-types' or
 287 KNOWN-TYPES if given,  and return that type name.
 288 If no suitable type is found, return nil."
 289   (let* ((known-list (or known-types x-dnd-known-types))
 290          (first-known-type (car known-list))
 291          (types-array types)
 292          (found (when first-known-type
 293                   (catch 'done
 294                     (dotimes (i (length types-array))
 295                       (let* ((type (aref types-array i))
 296                              (typename (if (symbolp type)
 297                                            (symbol-name type) type)))
 298                         (when (equal first-known-type typename)
 299                           (throw 'done first-known-type))))
 300                     nil))))
 301
 302     (if (and (not found) (cdr known-list))
 303         (x-dnd-choose-type types (cdr known-list))
 304       found)))
 305
 306 (defun x-dnd-drop-data (event frame window data type)
 307   "Drop one data item onto a frame.
 308 EVENT is the client message for the drop, FRAME is the frame the drop occurred
 309 on.  WINDOW is the window of FRAME where the drop happened.  DATA is the data
 310 received from the source, and type is the type for DATA, see
 311 `x-dnd-types-alist').
 312
 313 Returns the action used (move, copy, link, private) if drop was successful,
 314 nil if not."
 315   (let* ((type-info (assoc type x-dnd-types-alist))
 316          (handler (cdr type-info))
 317          (state (x-dnd-get-state-for-frame frame))
 318          (action (aref state 5))
 319          (w (posn-window (event-start event))))
 320     (when handler
 321       (if (and (window-live-p w)
 322                (not (window-minibuffer-p w))
 323                (not (window-dedicated-p w)))
 324           ;; If dropping in an ordinary window which we could use,
 325           ;; let dnd-open-file-other-window specify what to do.
 326           (progn
 327             (when (not mouse-yank-at-point)
 328               (goto-char (posn-point (event-start event))))
 329             (funcall handler window action data))
 330         ;; If we can't display the file here,
 331         ;; make a new window for it.
 332         (let ((dnd-open-file-other-window t))
 333           (select-frame frame)
 334           (funcall handler window action data))))))
 335
 336 (defun x-dnd-handle-drag-n-drop-event (event)
 337   "Receive drag and drop events (X client messages).
 338 Currently XDND, Motif and old KDE 1.x protocols are recognized."
 339   (interactive "e")
 340   (let* ((client-message (car (cdr (cdr event))))
 341          (window (posn-window (event-start event)))
 342          (message-atom (aref client-message 0))
 343          (frame (aref client-message 1))
 344          (format (aref client-message 2))
 345          (data (aref client-message 3)))
 346
 347     (cond ((equal "DndProtocol" message-atom)   ; Old KDE 1.x.
 348            (x-dnd-handle-old-kde event frame window message-atom format data))
 349
 350           ((equal "_MOTIF_DRAG_AND_DROP_MESSAGE" message-atom)  ; Motif
 351            (x-dnd-handle-motif event frame window message-atom format data))
 352
 353           ((and (> (length message-atom) 4)     ; XDND protocol.
 354                 (equal "Xdnd" (substring message-atom 0 4)))
 355            (x-dnd-handle-xdnd event frame window message-atom format data)))))
 356
 357
 358 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 359 ;;;  Old KDE protocol.  Only dropping of files.
 360
 361 (defun x-dnd-handle-old-kde (event frame window message format data)
 362   "Open the files in a KDE 1.x drop."
 363   (let ((values (x-window-property "DndSelection" frame nil 0 t)))
 364     (x-dnd-handle-uri-list window 'private
 365                            (replace-regexp-in-string "\0$" "" values))))
 366 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 367
 368
 369
 370 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 371 ;;;  XDND protocol.
 372
 373 (defvar x-dnd-xdnd-to-action
 374   '(("XdndActionPrivate" . private)
 375     ("XdndActionCopy" . copy)
 376     ("XdndActionMove" . move)
 377     ("XdndActionLink" . link)
 378     ("XdndActionAsk" . ask))
 379   "Mapping from XDND action types to lisp symbols.")
 380
 381 (defun x-dnd-init-xdnd-for-frame (frame)
 382   "Set the XdndAware property for FRAME to indicate that we do XDND."
 383   (x-change-window-property "XdndAware"
 384                             '(5)        ;; The version of XDND we support.
 385                             frame "ATOM" 32 t))
 386
 387 (defun x-dnd-get-drop-width-height (frame w accept)
 388   "Return the widht/height to be sent in a XDndStatus message.
 389 FRAME is the frame and W is the window where the drop happened.
 390 If ACCEPT is nil return 0 (empty rectangle),
 391 otherwise if W is a window, return its widht/height,
 392 otherwise return the frame width/height."
 393   (if accept
 394       (if (windowp w)   ;; w is not a window if dropping on the menu bar,
 395                         ;; scroll bar or tool bar.
 396           (let ((edges (window-inside-pixel-edges w)))
 397             (cons
 398              (- (nth 2 edges) (nth 0 edges))    ;; right - left
 399              (- (nth 3 edges) (nth 1 edges))))  ;; bottom - top
 400         (cons (frame-pixel-width frame)
 401               (frame-pixel-height frame)))
 402     0))
 403
 404 (defun x-dnd-get-drop-x-y (frame w)
 405   "Return the x/y coordinates to be sent in a XDndStatus message.
 406 Coordinates are required to be absolute.
 407 FRAME is the frame and W is the window where the drop happened.
 408 If W is a window, return its absolute corrdinates,
 409 otherwise return the frame coordinates."
 410   (let* ((frame-left (frame-parameter frame 'left))
 411          ;; If the frame is outside the display, frame-left looks like
 412          ;; '(0 -16).  Extract the -16.
 413          (frame-real-left (if (consp frame-left) (car (cdr frame-left))
 414                             frame-left))
 415          (frame-top (frame-parameter frame 'top))
 416          (frame-real-top (if (consp frame-top) (car (cdr frame-top))
 417                            frame-top)))
 418     (if (windowp w)
 419         (let ((edges (window-inside-pixel-edges w)))
 420           (cons
 421            (+ frame-real-left (nth 0 edges))
 422            (+ frame-real-top (nth 1 edges))))
 423       (cons frame-real-left frame-real-top))))
 424
 425 (declare-function x-get-atom-name "xselect.c")
 426 (declare-function x-send-client-message "xselect.c")
 427
 428 (defun x-dnd-handle-xdnd (event frame window message format data)
 429   "Receive one XDND event (client message) and send the appropriate reply.
 430 EVENT is the client message.  FRAME is where the mouse is now.
 431 WINDOW is the window within FRAME where the mouse is now.
 432 FORMAT is 32 (not used).  MESSAGE is the data part of an XClientMessageEvent."
 433   (cond ((equal "XdndEnter" message)
 434          (let* ((flags (aref data 1))
 435                 (version (and (consp flags) (ash (car flags) -8)))
 436                 (more-than-3 (and (consp flags) (cdr flags)))
 437                 (dnd-source (aref data 0)))
 438            (if version  ;; If flags is bad, version will be nil.
 439                (x-dnd-save-state
 440                 window nil nil
 441                 (if (> more-than-3 0)
 442                     (x-window-property "XdndTypeList"
 443                                        frame "AnyPropertyType"
 444                                        dnd-source nil t)
 445                   (vector (x-get-atom-name (aref data 2))
 446                           (x-get-atom-name (aref data 3))
 447                           (x-get-atom-name (aref data 4))))))))
 448
 449         ((equal "XdndPosition" message)
 450          (let* ((x (car (aref data 2)))
 451                 (y (cdr (aref data 2)))
 452                 (action (x-get-atom-name (aref data 4)))
 453                 (dnd-source (aref data 0))
 454                 (dnd-time (aref data 3))
 455                 (action-type (x-dnd-maybe-call-test-function
 456                               window
 457                               (cdr (assoc action x-dnd-xdnd-to-action))))
 458                 (reply-action (car (rassoc (car action-type)
 459                                            x-dnd-xdnd-to-action)))
 460                 (accept ;; 1 = accept, 0 = reject
 461                  (if (and reply-action action-type) 1 0))
 462                 (list-to-send
 463                  (list (string-to-number
 464                         (frame-parameter frame 'outer-window-id))
 465                        accept ;; 1 = Accept, 0 = reject.
 466                        (x-dnd-get-drop-x-y frame window)
 467                        (x-dnd-get-drop-width-height
 468                         frame window (eq accept 1))
 469                        (or reply-action 0)
 470                        )))
 471            (x-send-client-message
 472             frame dnd-source frame "XdndStatus" 32 list-to-send)
 473            ))
 474
 475         ((equal "XdndLeave" message)
 476          (x-dnd-forget-drop window))
 477
 478         ((equal "XdndDrop" message)
 479          (if (windowp window) (select-window window))
 480          (let* ((dnd-source (aref data 0))
 481                 (value (and (x-dnd-current-type window)
 482                             (x-get-selection-internal
 483                              'XdndSelection
 484                              (intern (x-dnd-current-type window)))))
 485                 success action ret-action)
 486
 487            (setq action (if value
 488                             (condition-case info
 489                                 (x-dnd-drop-data event frame window value
 490                                                  (x-dnd-current-type window))
 491                               (error
 492                                (message "Error: %s" info)
 493                                nil))))
 494
 495            (setq success (if action 1 0))
 496            (setq ret-action
 497                  (if (eq success 1)
 498                      (or (car (rassoc action x-dnd-xdnd-to-action))
 499                          "XdndActionPrivate")
 500                    0))
 501
 502            (x-send-client-message
 503             frame dnd-source frame "XdndFinished" 32
 504             (list (string-to-number (frame-parameter frame 'outer-window-id))
 505                   success       ;; 1 = Success, 0 = Error
 506                   (if success "XdndActionPrivate" 0)
 507                   ))
 508            (x-dnd-forget-drop window)))
 509
 510         (t (error "Unknown XDND message %s %s" message data))))
 511
 512 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 513 ;;;  Motif protocol.
 514
 515 (defun x-dnd-init-motif-for-frame (frame)
 516   "Set _MOTIF_DRAG_RECEIVER_INFO  for FRAME to indicate that we do Motif DND."
 517   (x-change-window-property "_MOTIF_DRAG_RECEIVER_INFO"
 518                             (list
 519                              (byteorder)
 520                              0                  ; The Motif DND version.
 521                              5                  ; We want drag dynamic.
 522                              0 0 0 0 0 0 0
 523                              0 0 0 0 0 0)       ; Property must be 16 bytes.
 524                             frame "_MOTIF_DRAG_RECEIVER_INFO" 8 t))
 525
 526 (defun x-dnd-get-motif-value (data offset size byteorder)
 527   (cond ((eq size 2)
 528          (if (eq byteorder ?l)
 529              (+ (ash (aref data (1+ offset)) 8)
 530                 (aref data offset))
 531            (+ (ash (aref data offset) 8)
 532               (aref data (1+ offset)))))
 533
 534         ((eq size 4)
 535          (if (eq byteorder ?l)
 536              (cons (+ (ash (aref data (+ 3 offset)) 8)
 537                       (aref data (+ 2 offset)))
 538                    (+ (ash (aref data (1+ offset)) 8)
 539                       (aref data offset)))
 540            (cons (+ (ash (aref data offset) 8)
 541                     (aref data (1+ offset)))
 542                  (+ (ash (aref data (+ 2 offset)) 8)
 543                     (aref data (+ 3 offset))))))))
 544
 545 (defun x-dnd-motif-value-to-list (value size byteorder)
 546   (let ((bytes (cond ((eq size 2)
 547                       (list (logand (lsh value -8) ?\xff)
 548                             (logand value ?\xff)))
 549
 550                      ((eq size 4)
 551                       (if (consp value)
 552                           (list (logand (lsh (car value) -8) ?\xff)
 553                                 (logand (car value) ?\xff)
 554                                 (logand (lsh (cdr value) -8) ?\xff)
 555                                 (logand (cdr value) ?\xff))
 556                         (list (logand (lsh value -24) ?\xff)
 557                               (logand (lsh value -16) ?\xff)
 558                               (logand (lsh value -8) ?\xff)
 559                               (logand value ?\xff)))))))
 560     (if (eq byteorder ?l)
 561         (reverse bytes)
 562       bytes)))
 563
 564
 565 (defvar x-dnd-motif-message-types
 566   '((0 . XmTOP_LEVEL_ENTER)
 567     (1 . XmTOP_LEVEL_LEAVE)
 568     (2 . XmDRAG_MOTION)
 569     (3 . XmDROP_SITE_ENTER)
 570     (4 . XmDROP_SITE_LEAVE)
 571     (5 . XmDROP_START)
 572     (6 . XmDROP_FINISH)
 573     (7 . XmDRAG_DROP_FINISH)
 574     (8 . XmOPERATION_CHANGED))
 575   "Mapping from numbers to Motif DND message types.")
 576
 577 (defvar x-dnd-motif-to-action
 578   '((1 . move)
 579     (2 . copy)
 580     (3 . link)  ; Both 3 and 4 has been seen as link.
 581     (4 . link)
 582     (2 . private)) ; Motif does not have private, so use copy for private.
 583   "Mapping from number to operation for Motif DND.")
 584
 585 (defun x-dnd-handle-motif (event frame window message-atom format data)
 586   (let* ((message-type (cdr (assoc (aref data 0) x-dnd-motif-message-types)))
 587          (source-byteorder (aref data 1))
 588          (my-byteorder (byteorder))
 589          (source-flags (x-dnd-get-motif-value data 2 2 source-byteorder))
 590          (source-action (cdr (assoc (logand ?\xF source-flags)
 591                                     x-dnd-motif-to-action))))
 592
 593     (cond ((eq message-type 'XmTOP_LEVEL_ENTER)
 594            (let* ((dnd-source (x-dnd-get-motif-value
 595                                data 8 4 source-byteorder))
 596                   (selection-atom (x-dnd-get-motif-value
 597                                    data 12 4 source-byteorder))
 598                   (atom-name (x-get-atom-name selection-atom))
 599                   (types (when atom-name
 600                            (x-get-selection-internal (intern atom-name)
 601                                                      'TARGETS))))
 602              (x-dnd-forget-drop frame)
 603              (when types (x-dnd-save-state window nil nil
 604                                            types
 605                                            dnd-source))))
 606
 607           ;; Can not forget drop here, LEAVE comes before DROP_START and
 608           ;; we need the state in DROP_START.
 609           ((eq message-type 'XmTOP_LEVEL_LEAVE)
 610            nil)
 611
 612           ((eq message-type 'XmDRAG_MOTION)
 613            (let* ((state (x-dnd-get-state-for-frame frame))
 614                   (timestamp (x-dnd-motif-value-to-list
 615                               (x-dnd-get-motif-value data 4 4
 616                                                      source-byteorder)
 617                               4 my-byteorder))
 618                   (x (x-dnd-motif-value-to-list
 619                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 620                       2 my-byteorder))
 621                   (y (x-dnd-motif-value-to-list
 622                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 623                       2 my-byteorder))
 624                   (dnd-source (aref state 6))
 625                   (first-move (not (aref state 3)))
 626                   (action-type (x-dnd-maybe-call-test-function
 627                                 window
 628                                 source-action))
 629                   (reply-action (car (rassoc (car action-type)
 630                                              x-dnd-motif-to-action)))
 631                   (reply-flags
 632                    (x-dnd-motif-value-to-list
 633                     (if reply-action
 634                         (+ reply-action
 635                            ?\x30        ; 30:  valid drop site
 636                            ?\x700)      ; 700: can do copy, move or link
 637                       ?\x30)            ; 30:  drop site, but noop.
 638                     2 my-byteorder))
 639                   (reply (append
 640                           (list
 641                            (+ ?\x80     ; 0x80 indicates a reply.
 642                               (if first-move
 643                                   3     ; First time, reply is SITE_ENTER.
 644                                 2))     ; Not first time, reply is DRAG_MOTION.
 645                            my-byteorder)
 646                           reply-flags
 647                           timestamp
 648                           x
 649                           y)))
 650              (x-send-client-message frame
 651                                     dnd-source
 652                                     frame
 653                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 654                                     8
 655                                     reply)))
 656
 657           ((eq message-type 'XmOPERATION_CHANGED)
 658            (let* ((state (x-dnd-get-state-for-frame frame))
 659                   (timestamp (x-dnd-motif-value-to-list
 660                               (x-dnd-get-motif-value data 4 4 source-byteorder)
 661                               4 my-byteorder))
 662                   (dnd-source (aref state 6))
 663                   (action-type (x-dnd-maybe-call-test-function
 664                                 window
 665                                 source-action))
 666                   (reply-action (car (rassoc (car action-type)
 667                                              x-dnd-motif-to-action)))
 668                   (reply-flags
 669                    (x-dnd-motif-value-to-list
 670                     (if reply-action
 671                         (+ reply-action
 672                            ?\x30        ; 30:  valid drop site
 673                            ?\x700)      ; 700: can do copy, move or link
 674                       ?\x30)            ; 30:  drop site, but noop
 675                     2 my-byteorder))
 676                   (reply (append
 677                           (list
 678                            (+ ?\x80     ; 0x80 indicates a reply.
 679                               8)        ; 8 is OPERATION_CHANGED
 680                            my-byteorder)
 681                           reply-flags
 682                           timestamp)))
 683              (x-send-client-message frame
 684                                     dnd-source
 685                                     frame
 686                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 687                                     8
 688                                     reply)))
 689
 690           ((eq message-type 'XmDROP_START)
 691            (let* ((x (x-dnd-motif-value-to-list
 692                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 693                       2 my-byteorder))
 694                   (y (x-dnd-motif-value-to-list
 695                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 696                       2 my-byteorder))
 697                   (selection-atom (x-dnd-get-motif-value
 698                                    data 12 4 source-byteorder))
 699                   (atom-name (x-get-atom-name selection-atom))
 700                   (dnd-source (x-dnd-get-motif-value
 701                                data 16 4 source-byteorder))
 702                   (action-type (x-dnd-maybe-call-test-function
 703                                 window
 704                                 source-action))
 705                   (reply-action (car (rassoc (car action-type)
 706                                              x-dnd-motif-to-action)))
 707                   (reply-flags
 708                    (x-dnd-motif-value-to-list
 709                     (if reply-action
 710                         (+ reply-action
 711                            ?\x30        ; 30:  valid drop site
 712                            ?\x700)      ; 700: can do copy, move or link
 713                       (+ ?\x30          ; 30:  drop site, but noop.
 714                          ?\x200))       ; 200: drop cancel.
 715                     2 my-byteorder))
 716                   (reply (append
 717                           (list
 718                            (+ ?\x80     ; 0x80 indicates a reply.
 719                               5)        ; DROP_START.
 720                            my-byteorder)
 721                           reply-flags
 722                           x
 723                           y))
 724                   (timestamp (x-dnd-get-motif-value
 725                               data 4 4 source-byteorder))
 726                   action)
 727
 728              (x-send-client-message frame
 729                                     dnd-source
 730                                     frame
 731                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 732                                     8
 733                                     reply)
 734              (setq action
 735                    (when (and reply-action atom-name)
 736                      (let* ((value (x-get-selection-internal
 737                                     (intern atom-name)
 738                                     (intern (x-dnd-current-type window)))))
 739                        (when value
 740                          (condition-case info
 741                              (x-dnd-drop-data event frame window value
 742                                               (x-dnd-current-type window))
 743                            (error
 744                             (message "Error: %s" info)
 745                             nil))))))
 746              (x-get-selection-internal
 747               (intern atom-name)
 748               (if action 'XmTRANSFER_SUCCESS 'XmTRANSFER_FAILURE)
 749               timestamp)
 750              (x-dnd-forget-drop frame)))
 751
 752           (t (error "Unknown Motif DND message %s %s" message-atom data)))))
 753
 754
 755 ;;;
 756
 757 (provide 'x-dnd)
 758
 759 ;; arch-tag: b621fb7e-50da-4323-850b-5fc71ae64621
 760 ;;; x-dnd.el ends here