lisp/x-dnd.el

   1 ;;; x-dnd.el --- drag and drop support for X.
   2
   3 ;; Copyright (C) 2004, 2005, 2006, 2007 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
 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 (defun x-dnd-handle-xdnd (event frame window message format data)
 426   "Receive one XDND event (client message) and send the appropriate reply.
 427 EVENT is the client message.  FRAME is where the mouse is now.
 428 WINDOW is the window within FRAME where the mouse is now.
 429 FORMAT is 32 (not used).  MESSAGE is the data part of an XClientMessageEvent."
 430   (cond ((equal "XdndEnter" message)
 431          (let* ((flags (aref data 1))
 432                 (version (and (consp flags) (ash (car flags) -8)))
 433                 (more-than-3 (and (consp flags) (cdr flags)))
 434                 (dnd-source (aref data 0)))
 435            (if version  ;; If flags is bad, version will be nil.
 436                (x-dnd-save-state
 437                 window nil nil
 438                 (if (> more-than-3 0)
 439                     (x-window-property "XdndTypeList"
 440                                        frame "AnyPropertyType"
 441                                        dnd-source nil t)
 442                   (vector (x-get-atom-name (aref data 2))
 443                           (x-get-atom-name (aref data 3))
 444                           (x-get-atom-name (aref data 4))))))))
 445
 446         ((equal "XdndPosition" message)
 447          (let* ((x (car (aref data 2)))
 448                 (y (cdr (aref data 2)))
 449                 (action (x-get-atom-name (aref data 4)))
 450                 (dnd-source (aref data 0))
 451                 (dnd-time (aref data 3))
 452                 (action-type (x-dnd-maybe-call-test-function
 453                               window
 454                               (cdr (assoc action x-dnd-xdnd-to-action))))
 455                 (reply-action (car (rassoc (car action-type)
 456                                            x-dnd-xdnd-to-action)))
 457                 (accept ;; 1 = accept, 0 = reject
 458                  (if (and reply-action action-type) 1 0))
 459                 (list-to-send
 460                  (list (string-to-number
 461                         (frame-parameter frame 'outer-window-id))
 462                        accept ;; 1 = Accept, 0 = reject.
 463                        (x-dnd-get-drop-x-y frame window)
 464                        (x-dnd-get-drop-width-height
 465                         frame window (eq accept 1))
 466                        (or reply-action 0)
 467                        )))
 468            (x-send-client-message
 469             frame dnd-source frame "XdndStatus" 32 list-to-send)
 470            ))
 471
 472         ((equal "XdndLeave" message)
 473          (x-dnd-forget-drop window))
 474
 475         ((equal "XdndDrop" message)
 476          (if (windowp window) (select-window window))
 477          (let* ((dnd-source (aref data 0))
 478                 (value (and (x-dnd-current-type window)
 479                             (x-get-selection-internal
 480                              'XdndSelection
 481                              (intern (x-dnd-current-type window)))))
 482                 success action ret-action)
 483
 484            (setq action (if value
 485                             (condition-case info
 486                                 (x-dnd-drop-data event frame window value
 487                                                  (x-dnd-current-type window))
 488                               (error
 489                                (message "Error: %s" info)
 490                                nil))))
 491
 492            (setq success (if action 1 0))
 493            (setq ret-action
 494                  (if (eq success 1)
 495                      (or (car (rassoc action x-dnd-xdnd-to-action))
 496                          "XdndActionPrivate")
 497                    0))
 498
 499            (x-send-client-message
 500             frame dnd-source frame "XdndFinished" 32
 501             (list (string-to-number (frame-parameter frame 'outer-window-id))
 502                   success       ;; 1 = Success, 0 = Error
 503                   (if success "XdndActionPrivate" 0)
 504                   ))
 505            (x-dnd-forget-drop window)))
 506
 507         (t (error "Unknown XDND message %s %s" message data))))
 508
 509 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 510 ;;;  Motif protocol.
 511
 512 (defun x-dnd-init-motif-for-frame (frame)
 513   "Set _MOTIF_DRAG_RECEIVER_INFO  for FRAME to indicate that we do Motif DND."
 514   (x-change-window-property "_MOTIF_DRAG_RECEIVER_INFO"
 515                             (list
 516                              (byteorder)
 517                              0                  ; The Motif DND version.
 518                              5                  ; We want drag dynamic.
 519                              0 0 0 0 0 0 0
 520                              0 0 0 0 0 0)       ; Property must be 16 bytes.
 521                             frame "_MOTIF_DRAG_RECEIVER_INFO" 8 t))
 522
 523 (defun x-dnd-get-motif-value (data offset size byteorder)
 524   (cond ((eq size 2)
 525          (if (eq byteorder ?l)
 526              (+ (ash (aref data (1+ offset)) 8)
 527                 (aref data offset))
 528            (+ (ash (aref data offset) 8)
 529               (aref data (1+ offset)))))
 530
 531         ((eq size 4)
 532          (if (eq byteorder ?l)
 533              (cons (+ (ash (aref data (+ 3 offset)) 8)
 534                       (aref data (+ 2 offset)))
 535                    (+ (ash (aref data (1+ offset)) 8)
 536                       (aref data offset)))
 537            (cons (+ (ash (aref data offset) 8)
 538                     (aref data (1+ offset)))
 539                  (+ (ash (aref data (+ 2 offset)) 8)
 540                     (aref data (+ 3 offset))))))))
 541
 542 (defun x-dnd-motif-value-to-list (value size byteorder)
 543   (let ((bytes (cond ((eq size 2)
 544                       (list (logand (lsh value -8) ?\xff)
 545                             (logand value ?\xff)))
 546
 547                      ((eq size 4)
 548                       (if (consp value)
 549                           (list (logand (lsh (car value) -8) ?\xff)
 550                                 (logand (car value) ?\xff)
 551                                 (logand (lsh (cdr value) -8) ?\xff)
 552                                 (logand (cdr value) ?\xff))
 553                         (list (logand (lsh value -24) ?\xff)
 554                               (logand (lsh value -16) ?\xff)
 555                               (logand (lsh value -8) ?\xff)
 556                               (logand value ?\xff)))))))
 557     (if (eq byteorder ?l)
 558         (reverse bytes)
 559       bytes)))
 560
 561
 562 (defvar x-dnd-motif-message-types
 563   '((0 . XmTOP_LEVEL_ENTER)
 564     (1 . XmTOP_LEVEL_LEAVE)
 565     (2 . XmDRAG_MOTION)
 566     (3 . XmDROP_SITE_ENTER)
 567     (4 . XmDROP_SITE_LEAVE)
 568     (5 . XmDROP_START)
 569     (6 . XmDROP_FINISH)
 570     (7 . XmDRAG_DROP_FINISH)
 571     (8 . XmOPERATION_CHANGED))
 572   "Mapping from numbers to Motif DND message types.")
 573
 574 (defvar x-dnd-motif-to-action
 575   '((1 . move)
 576     (2 . copy)
 577     (3 . link)  ; Both 3 and 4 has been seen as link.
 578     (4 . link)
 579     (2 . private)) ; Motif does not have private, so use copy for private.
 580   "Mapping from number to operation for Motif DND.")
 581
 582 (defun x-dnd-handle-motif (event frame window message-atom format data)
 583   (let* ((message-type (cdr (assoc (aref data 0) x-dnd-motif-message-types)))
 584          (source-byteorder (aref data 1))
 585          (my-byteorder (byteorder))
 586          (source-flags (x-dnd-get-motif-value data 2 2 source-byteorder))
 587          (source-action (cdr (assoc (logand ?\xF source-flags)
 588                                     x-dnd-motif-to-action))))
 589
 590     (cond ((eq message-type 'XmTOP_LEVEL_ENTER)
 591            (let* ((dnd-source (x-dnd-get-motif-value
 592                                data 8 4 source-byteorder))
 593                   (selection-atom (x-dnd-get-motif-value
 594                                    data 12 4 source-byteorder))
 595                   (atom-name (x-get-atom-name selection-atom))
 596                   (types (when atom-name
 597                            (x-get-selection-internal (intern atom-name)
 598                                                      'TARGETS))))
 599              (x-dnd-forget-drop frame)
 600              (when types (x-dnd-save-state window nil nil
 601                                            types
 602                                            dnd-source))))
 603
 604           ;; Can not forget drop here, LEAVE comes before DROP_START and
 605           ;; we need the state in DROP_START.
 606           ((eq message-type 'XmTOP_LEVEL_LEAVE)
 607            nil)
 608
 609           ((eq message-type 'XmDRAG_MOTION)
 610            (let* ((state (x-dnd-get-state-for-frame frame))
 611                   (timestamp (x-dnd-motif-value-to-list
 612                               (x-dnd-get-motif-value data 4 4
 613                                                      source-byteorder)
 614                               4 my-byteorder))
 615                   (x (x-dnd-motif-value-to-list
 616                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 617                       2 my-byteorder))
 618                   (y (x-dnd-motif-value-to-list
 619                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 620                       2 my-byteorder))
 621                   (dnd-source (aref state 6))
 622                   (first-move (not (aref state 3)))
 623                   (action-type (x-dnd-maybe-call-test-function
 624                                 window
 625                                 source-action))
 626                   (reply-action (car (rassoc (car action-type)
 627                                              x-dnd-motif-to-action)))
 628                   (reply-flags
 629                    (x-dnd-motif-value-to-list
 630                     (if reply-action
 631                         (+ reply-action
 632                            ?\x30        ; 30:  valid drop site
 633                            ?\x700)      ; 700: can do copy, move or link
 634                       ?\x30)            ; 30:  drop site, but noop.
 635                     2 my-byteorder))
 636                   (reply (append
 637                           (list
 638                            (+ ?\x80     ; 0x80 indicates a reply.
 639                               (if first-move
 640                                   3     ; First time, reply is SITE_ENTER.
 641                                 2))     ; Not first time, reply is DRAG_MOTION.
 642                            my-byteorder)
 643                           reply-flags
 644                           timestamp
 645                           x
 646                           y)))
 647              (x-send-client-message frame
 648                                     dnd-source
 649                                     frame
 650                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 651                                     8
 652                                     reply)))
 653
 654           ((eq message-type 'XmOPERATION_CHANGED)
 655            (let* ((state (x-dnd-get-state-for-frame frame))
 656                   (timestamp (x-dnd-motif-value-to-list
 657                               (x-dnd-get-motif-value data 4 4 source-byteorder)
 658                               4 my-byteorder))
 659                   (dnd-source (aref state 6))
 660                   (action-type (x-dnd-maybe-call-test-function
 661                                 window
 662                                 source-action))
 663                   (reply-action (car (rassoc (car action-type)
 664                                              x-dnd-motif-to-action)))
 665                   (reply-flags
 666                    (x-dnd-motif-value-to-list
 667                     (if reply-action
 668                         (+ reply-action
 669                            ?\x30        ; 30:  valid drop site
 670                            ?\x700)      ; 700: can do copy, move or link
 671                       ?\x30)            ; 30:  drop site, but noop
 672                     2 my-byteorder))
 673                   (reply (append
 674                           (list
 675                            (+ ?\x80     ; 0x80 indicates a reply.
 676                               8)        ; 8 is OPERATION_CHANGED
 677                            my-byteorder)
 678                           reply-flags
 679                           timestamp)))
 680              (x-send-client-message frame
 681                                     dnd-source
 682                                     frame
 683                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 684                                     8
 685                                     reply)))
 686
 687           ((eq message-type 'XmDROP_START)
 688            (let* ((x (x-dnd-motif-value-to-list
 689                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 690                       2 my-byteorder))
 691                   (y (x-dnd-motif-value-to-list
 692                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 693                       2 my-byteorder))
 694                   (selection-atom (x-dnd-get-motif-value
 695                                    data 12 4 source-byteorder))
 696                   (atom-name (x-get-atom-name selection-atom))
 697                   (dnd-source (x-dnd-get-motif-value
 698                                data 16 4 source-byteorder))
 699                   (action-type (x-dnd-maybe-call-test-function
 700                                 window
 701                                 source-action))
 702                   (reply-action (car (rassoc (car action-type)
 703                                              x-dnd-motif-to-action)))
 704                   (reply-flags
 705                    (x-dnd-motif-value-to-list
 706                     (if reply-action
 707                         (+ reply-action
 708                            ?\x30        ; 30:  valid drop site
 709                            ?\x700)      ; 700: can do copy, move or link
 710                       (+ ?\x30          ; 30:  drop site, but noop.
 711                          ?\x200))       ; 200: drop cancel.
 712                     2 my-byteorder))
 713                   (reply (append
 714                           (list
 715                            (+ ?\x80     ; 0x80 indicates a reply.
 716                               5)        ; DROP_START.
 717                            my-byteorder)
 718                           reply-flags
 719                           x
 720                           y))
 721                   (timestamp (x-dnd-get-motif-value
 722                               data 4 4 source-byteorder))
 723                   action)
 724
 725              (x-send-client-message frame
 726                                     dnd-source
 727                                     frame
 728                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 729                                     8
 730                                     reply)
 731              (setq action
 732                    (when (and reply-action atom-name)
 733                      (let* ((value (x-get-selection-internal
 734                                     (intern atom-name)
 735                                     (intern (x-dnd-current-type window)))))
 736                        (when value
 737                          (condition-case info
 738                              (x-dnd-drop-data event frame window value
 739                                               (x-dnd-current-type window))
 740                            (error
 741                             (message "Error: %s" info)
 742                             nil))))))
 743              (x-get-selection-internal
 744               (intern atom-name)
 745               (if action 'XmTRANSFER_SUCCESS 'XmTRANSFER_FAILURE)
 746               timestamp)
 747              (x-dnd-forget-drop frame)))
 748
 749           (t (error "Unknown Motif DND message %s %s" message-atom data)))))
 750
 751
 752 ;;;
 753
 754 (provide 'x-dnd)
 755
 756 ;;; arch-tag: b621fb7e-50da-4323-850b-5fc71ae64621
 757 ;;; x-dnd.el ends here