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 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 types
  41 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) if drop
  75 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 a frame
 149 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 handeled, 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 handeled, 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 occurred
 307 on.  WINDOW is the window of FRAME where the drop happened.  DATA is the data
 308 received from the source, and type is the type for DATA, see
 309 `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 (defun x-dnd-handle-old-kde (event frame window message format data)
 360   "Open the files in a KDE 1.x drop."
 361   (let ((values (x-window-property "DndSelection" frame nil 0 t)))
 362     (x-dnd-handle-uri-list window 'private
 363                            (replace-regexp-in-string "\0$" "" values))))
 364 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 365
 366
 367
 368 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 369 ;;;  XDND protocol.
 370
 371 (defvar x-dnd-xdnd-to-action
 372   '(("XdndActionPrivate" . private)
 373     ("XdndActionCopy" . copy)
 374     ("XdndActionMove" . move)
 375     ("XdndActionLink" . link)
 376     ("XdndActionAsk" . ask))
 377   "Mapping from XDND action types to lisp symbols.")
 378
 379 (defun x-dnd-init-xdnd-for-frame (frame)
 380   "Set the XdndAware property for FRAME to indicate that we do XDND."
 381   (x-change-window-property "XdndAware"
 382                             '(5)        ;; The version of XDND we support.
 383                             frame "ATOM" 32 t))
 384
 385 (defun x-dnd-get-drop-width-height (frame w accept)
 386   "Return the widht/height to be sent in a XDndStatus message.
 387 FRAME is the frame and W is the window where the drop happened.
 388 If ACCEPT is nil return 0 (empty rectangle),
 389 otherwise if W is a window, return its widht/height,
 390 otherwise return the frame width/height."
 391   (if accept
 392       (if (windowp w)   ;; w is not a window if dropping on the menu bar,
 393                         ;; scroll bar or tool bar.
 394           (let ((edges (window-inside-pixel-edges w)))
 395             (cons
 396              (- (nth 2 edges) (nth 0 edges))    ;; right - left
 397              (- (nth 3 edges) (nth 1 edges))))  ;; bottom - top
 398         (cons (frame-pixel-width frame)
 399               (frame-pixel-height frame)))
 400     0))
 401
 402 (defun x-dnd-get-drop-x-y (frame w)
 403   "Return the x/y coordinates to be sent in a XDndStatus message.
 404 Coordinates are required to be absolute.
 405 FRAME is the frame and W is the window where the drop happened.
 406 If W is a window, return its absolute corrdinates,
 407 otherwise return the frame coordinates."
 408   (let* ((frame-left (frame-parameter frame 'left))
 409          ;; If the frame is outside the display, frame-left looks like
 410          ;; '(0 -16).  Extract the -16.
 411          (frame-real-left (if (consp frame-left) (car (cdr frame-left))
 412                             frame-left))
 413          (frame-top (frame-parameter frame 'top))
 414          (frame-real-top (if (consp frame-top) (car (cdr frame-top))
 415                            frame-top)))
 416     (if (windowp w)
 417         (let ((edges (window-inside-pixel-edges w)))
 418           (cons
 419            (+ frame-real-left (nth 0 edges))
 420            (+ frame-real-top (nth 1 edges))))
 421       (cons frame-real-left frame-real-top))))
 422
 423 (declare-function x-get-atom-name "xselect.c")
 424 (declare-function x-send-client-message "xselect.c")
 425
 426 (defun x-dnd-handle-xdnd (event frame window message format data)
 427   "Receive one XDND event (client message) and send the appropriate reply.
 428 EVENT is the client message.  FRAME is where the mouse is now.
 429 WINDOW is the window within FRAME where the mouse is now.
 430 FORMAT is 32 (not used).  MESSAGE is the data part of an XClientMessageEvent."
 431   (cond ((equal "XdndEnter" message)
 432          (let* ((flags (aref data 1))
 433                 (version (and (consp flags) (ash (car flags) -8)))
 434                 (more-than-3 (and (consp flags) (cdr flags)))
 435                 (dnd-source (aref data 0)))
 436            (if version  ;; If flags is bad, version will be nil.
 437                (x-dnd-save-state
 438                 window nil nil
 439                 (if (> more-than-3 0)
 440                     (x-window-property "XdndTypeList"
 441                                        frame "AnyPropertyType"
 442                                        dnd-source nil t)
 443                   (vector (x-get-atom-name (aref data 2))
 444                           (x-get-atom-name (aref data 3))
 445                           (x-get-atom-name (aref data 4))))))))
 446
 447         ((equal "XdndPosition" message)
 448          (let* ((x (car (aref data 2)))
 449                 (y (cdr (aref data 2)))
 450                 (action (x-get-atom-name (aref data 4)))
 451                 (dnd-source (aref data 0))
 452                 (dnd-time (aref data 3))
 453                 (action-type (x-dnd-maybe-call-test-function
 454                               window
 455                               (cdr (assoc action x-dnd-xdnd-to-action))))
 456                 (reply-action (car (rassoc (car action-type)
 457                                            x-dnd-xdnd-to-action)))
 458                 (accept ;; 1 = accept, 0 = reject
 459                  (if (and reply-action action-type) 1 0))
 460                 (list-to-send
 461                  (list (string-to-number
 462                         (frame-parameter frame 'outer-window-id))
 463                        accept ;; 1 = Accept, 0 = reject.
 464                        (x-dnd-get-drop-x-y frame window)
 465                        (x-dnd-get-drop-width-height
 466                         frame window (eq accept 1))
 467                        (or reply-action 0)
 468                        )))
 469            (x-send-client-message
 470             frame dnd-source frame "XdndStatus" 32 list-to-send)
 471            ))
 472
 473         ((equal "XdndLeave" message)
 474          (x-dnd-forget-drop window))
 475
 476         ((equal "XdndDrop" message)
 477          (if (windowp window) (select-window window))
 478          (let* ((dnd-source (aref data 0))
 479                 (value (and (x-dnd-current-type window)
 480                             (x-get-selection-internal
 481                              'XdndSelection
 482                              (intern (x-dnd-current-type window)))))
 483                 success action ret-action)
 484
 485            (setq action (if value
 486                             (condition-case info
 487                                 (x-dnd-drop-data event frame window value
 488                                                  (x-dnd-current-type window))
 489                               (error
 490                                (message "Error: %s" info)
 491                                nil))))
 492
 493            (setq success (if action 1 0))
 494            (setq ret-action
 495                  (if (eq success 1)
 496                      (or (car (rassoc action x-dnd-xdnd-to-action))
 497                          "XdndActionPrivate")
 498                    0))
 499
 500            (x-send-client-message
 501             frame dnd-source frame "XdndFinished" 32
 502             (list (string-to-number (frame-parameter frame 'outer-window-id))
 503                   success       ;; 1 = Success, 0 = Error
 504                   (if success "XdndActionPrivate" 0)
 505                   ))
 506            (x-dnd-forget-drop window)))
 507
 508         (t (error "Unknown XDND message %s %s" message data))))
 509
 510 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 511 ;;;  Motif protocol.
 512
 513 (defun x-dnd-init-motif-for-frame (frame)
 514   "Set _MOTIF_DRAG_RECEIVER_INFO  for FRAME to indicate that we do Motif DND."
 515   (x-change-window-property "_MOTIF_DRAG_RECEIVER_INFO"
 516                             (list
 517                              (byteorder)
 518                              0                  ; The Motif DND version.
 519                              5                  ; We want drag dynamic.
 520                              0 0 0 0 0 0 0
 521                              0 0 0 0 0 0)       ; Property must be 16 bytes.
 522                             frame "_MOTIF_DRAG_RECEIVER_INFO" 8 t))
 523
 524 (defun x-dnd-get-motif-value (data offset size byteorder)
 525   (cond ((eq size 2)
 526          (if (eq byteorder ?l)
 527              (+ (ash (aref data (1+ offset)) 8)
 528                 (aref data offset))
 529            (+ (ash (aref data offset) 8)
 530               (aref data (1+ offset)))))
 531
 532         ((eq size 4)
 533          (if (eq byteorder ?l)
 534              (cons (+ (ash (aref data (+ 3 offset)) 8)
 535                       (aref data (+ 2 offset)))
 536                    (+ (ash (aref data (1+ offset)) 8)
 537                       (aref data offset)))
 538            (cons (+ (ash (aref data offset) 8)
 539                     (aref data (1+ offset)))
 540                  (+ (ash (aref data (+ 2 offset)) 8)
 541                     (aref data (+ 3 offset))))))))
 542
 543 (defun x-dnd-motif-value-to-list (value size byteorder)
 544   (let ((bytes (cond ((eq size 2)
 545                       (list (logand (lsh value -8) ?\xff)
 546                             (logand value ?\xff)))
 547
 548                      ((eq size 4)
 549                       (if (consp value)
 550                           (list (logand (lsh (car value) -8) ?\xff)
 551                                 (logand (car value) ?\xff)
 552                                 (logand (lsh (cdr value) -8) ?\xff)
 553                                 (logand (cdr value) ?\xff))
 554                         (list (logand (lsh value -24) ?\xff)
 555                               (logand (lsh value -16) ?\xff)
 556                               (logand (lsh value -8) ?\xff)
 557                               (logand value ?\xff)))))))
 558     (if (eq byteorder ?l)
 559         (reverse bytes)
 560       bytes)))
 561
 562
 563 (defvar x-dnd-motif-message-types
 564   '((0 . XmTOP_LEVEL_ENTER)
 565     (1 . XmTOP_LEVEL_LEAVE)
 566     (2 . XmDRAG_MOTION)
 567     (3 . XmDROP_SITE_ENTER)
 568     (4 . XmDROP_SITE_LEAVE)
 569     (5 . XmDROP_START)
 570     (6 . XmDROP_FINISH)
 571     (7 . XmDRAG_DROP_FINISH)
 572     (8 . XmOPERATION_CHANGED))
 573   "Mapping from numbers to Motif DND message types.")
 574
 575 (defvar x-dnd-motif-to-action
 576   '((1 . move)
 577     (2 . copy)
 578     (3 . link)  ; Both 3 and 4 has been seen as link.
 579     (4 . link)
 580     (2 . private)) ; Motif does not have private, so use copy for private.
 581   "Mapping from number to operation for Motif DND.")
 582
 583 (defun x-dnd-handle-motif (event frame window message-atom format data)
 584   (let* ((message-type (cdr (assoc (aref data 0) x-dnd-motif-message-types)))
 585          (source-byteorder (aref data 1))
 586          (my-byteorder (byteorder))
 587          (source-flags (x-dnd-get-motif-value data 2 2 source-byteorder))
 588          (source-action (cdr (assoc (logand ?\xF source-flags)
 589                                     x-dnd-motif-to-action))))
 590
 591     (cond ((eq message-type 'XmTOP_LEVEL_ENTER)
 592            (let* ((dnd-source (x-dnd-get-motif-value
 593                                data 8 4 source-byteorder))
 594                   (selection-atom (x-dnd-get-motif-value
 595                                    data 12 4 source-byteorder))
 596                   (atom-name (x-get-atom-name selection-atom))
 597                   (types (when atom-name
 598                            (x-get-selection-internal (intern atom-name)
 599                                                      'TARGETS))))
 600              (x-dnd-forget-drop frame)
 601              (when types (x-dnd-save-state window nil nil
 602                                            types
 603                                            dnd-source))))
 604
 605           ;; Can not forget drop here, LEAVE comes before DROP_START and
 606           ;; we need the state in DROP_START.
 607           ((eq message-type 'XmTOP_LEVEL_LEAVE)
 608            nil)
 609
 610           ((eq message-type 'XmDRAG_MOTION)
 611            (let* ((state (x-dnd-get-state-for-frame frame))
 612                   (timestamp (x-dnd-motif-value-to-list
 613                               (x-dnd-get-motif-value data 4 4
 614                                                      source-byteorder)
 615                               4 my-byteorder))
 616                   (x (x-dnd-motif-value-to-list
 617                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 618                       2 my-byteorder))
 619                   (y (x-dnd-motif-value-to-list
 620                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 621                       2 my-byteorder))
 622                   (dnd-source (aref state 6))
 623                   (first-move (not (aref state 3)))
 624                   (action-type (x-dnd-maybe-call-test-function
 625                                 window
 626                                 source-action))
 627                   (reply-action (car (rassoc (car action-type)
 628                                              x-dnd-motif-to-action)))
 629                   (reply-flags
 630                    (x-dnd-motif-value-to-list
 631                     (if reply-action
 632                         (+ reply-action
 633                            ?\x30        ; 30:  valid drop site
 634                            ?\x700)      ; 700: can do copy, move or link
 635                       ?\x30)            ; 30:  drop site, but noop.
 636                     2 my-byteorder))
 637                   (reply (append
 638                           (list
 639                            (+ ?\x80     ; 0x80 indicates a reply.
 640                               (if first-move
 641                                   3     ; First time, reply is SITE_ENTER.
 642                                 2))     ; Not first time, reply is DRAG_MOTION.
 643                            my-byteorder)
 644                           reply-flags
 645                           timestamp
 646                           x
 647                           y)))
 648              (x-send-client-message frame
 649                                     dnd-source
 650                                     frame
 651                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 652                                     8
 653                                     reply)))
 654
 655           ((eq message-type 'XmOPERATION_CHANGED)
 656            (let* ((state (x-dnd-get-state-for-frame frame))
 657                   (timestamp (x-dnd-motif-value-to-list
 658                               (x-dnd-get-motif-value data 4 4 source-byteorder)
 659                               4 my-byteorder))
 660                   (dnd-source (aref state 6))
 661                   (action-type (x-dnd-maybe-call-test-function
 662                                 window
 663                                 source-action))
 664                   (reply-action (car (rassoc (car action-type)
 665                                              x-dnd-motif-to-action)))
 666                   (reply-flags
 667                    (x-dnd-motif-value-to-list
 668                     (if reply-action
 669                         (+ reply-action
 670                            ?\x30        ; 30:  valid drop site
 671                            ?\x700)      ; 700: can do copy, move or link
 672                       ?\x30)            ; 30:  drop site, but noop
 673                     2 my-byteorder))
 674                   (reply (append
 675                           (list
 676                            (+ ?\x80     ; 0x80 indicates a reply.
 677                               8)        ; 8 is OPERATION_CHANGED
 678                            my-byteorder)
 679                           reply-flags
 680                           timestamp)))
 681              (x-send-client-message frame
 682                                     dnd-source
 683                                     frame
 684                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 685                                     8
 686                                     reply)))
 687
 688           ((eq message-type 'XmDROP_START)
 689            (let* ((x (x-dnd-motif-value-to-list
 690                       (x-dnd-get-motif-value data 8 2 source-byteorder)
 691                       2 my-byteorder))
 692                   (y (x-dnd-motif-value-to-list
 693                       (x-dnd-get-motif-value data 10 2 source-byteorder)
 694                       2 my-byteorder))
 695                   (selection-atom (x-dnd-get-motif-value
 696                                    data 12 4 source-byteorder))
 697                   (atom-name (x-get-atom-name selection-atom))
 698                   (dnd-source (x-dnd-get-motif-value
 699                                data 16 4 source-byteorder))
 700                   (action-type (x-dnd-maybe-call-test-function
 701                                 window
 702                                 source-action))
 703                   (reply-action (car (rassoc (car action-type)
 704                                              x-dnd-motif-to-action)))
 705                   (reply-flags
 706                    (x-dnd-motif-value-to-list
 707                     (if reply-action
 708                         (+ reply-action
 709                            ?\x30        ; 30:  valid drop site
 710                            ?\x700)      ; 700: can do copy, move or link
 711                       (+ ?\x30          ; 30:  drop site, but noop.
 712                          ?\x200))       ; 200: drop cancel.
 713                     2 my-byteorder))
 714                   (reply (append
 715                           (list
 716                            (+ ?\x80     ; 0x80 indicates a reply.
 717                               5)        ; DROP_START.
 718                            my-byteorder)
 719                           reply-flags
 720                           x
 721                           y))
 722                   (timestamp (x-dnd-get-motif-value
 723                               data 4 4 source-byteorder))
 724                   action)
 725
 726              (x-send-client-message frame
 727                                     dnd-source
 728                                     frame
 729                                     "_MOTIF_DRAG_AND_DROP_MESSAGE"
 730                                     8
 731                                     reply)
 732              (setq action
 733                    (when (and reply-action atom-name)
 734                      (let* ((value (x-get-selection-internal
 735                                     (intern atom-name)
 736                                     (intern (x-dnd-current-type window)))))
 737                        (when value
 738                          (condition-case info
 739                              (x-dnd-drop-data event frame window value
 740                                               (x-dnd-current-type window))
 741                            (error
 742                             (message "Error: %s" info)
 743                             nil))))))
 744              (x-get-selection-internal
 745               (intern atom-name)
 746               (if action 'XmTRANSFER_SUCCESS 'XmTRANSFER_FAILURE)
 747               timestamp)
 748              (x-dnd-forget-drop frame)))
 749
 750           (t (error "Unknown Motif DND message %s %s" message-atom data)))))
 751
 752
 753 ;;;
 754
 755 (provide 'x-dnd)
 756
 757 ;; arch-tag: b621fb7e-50da-4323-850b-5fc71ae64621
 758 ;;; x-dnd.el ends here