Add support for dragging text onto windows that don't support any DND protocol

* src/xselect.c (x_own_selection): Export function.
(x_handle_selection_request): Handle selection requests to the
pending DND time.
(x_set_pending_dnd_time): New function.

* src/xterm.c (x_dnd_send_unsupported_drop): New function.
Implement according to the suggestions in the XDND protocol
specification.
(x_dnd_get_target_window): Return the toplevel window as well.
(x_dnd_cleanup_drag_and_drop, x_dnd_begin_drag_and_drop)
(x_dnd_update_state, handle_one_xevent): Send unsupported drops
and use last seen toplevel instead of target for `return_frame'.
* src/xterm.h: Update prototypes.

diff --git a/src/xselect.c b/src/xselect.c
index 7719876884eb9c63de366507294c9e0580b621c3..2969c816a3601fa243a397070185baf384f536d7 100644 (file)
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -39,6 +39,8 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 #include <X11/Xproto.h>
 
+static Time pending_dnd_time;
+
 struct prop_location;
 struct selection_data;
 
@@ -304,7 +306,7 @@ x_atom_to_symbol (struct x_display_info *dpyinfo, Atom atom)
    Update the Vselection_alist so that we can reply to later requests for
    our selection.  */
 
-static void
+void
 x_own_selection (Lisp_Object selection_name, Lisp_Object selection_value,
                 Lisp_Object frame)
 {
@@ -771,6 +773,12 @@ x_handle_selection_request (struct selection_input_event *event)
 
   if (!dpyinfo) goto DONE;
 
+  /* This is how the XDND protocol recommends dropping text onto a
+     target that doesn't support XDND.  */
+  if (SELECTION_EVENT_TIME (event) == pending_dnd_time + 1
+      || SELECTION_EVENT_TIME (event) == pending_dnd_time + 2)
+    selection_symbol = QXdndSelection;
+
   local_selection_data = LOCAL_SELECTION (selection_symbol, dpyinfo);
 
   /* Decline if we don't own any selections.  */
@@ -2671,6 +2679,12 @@ x_timestamp_for_selection (struct x_display_info *dpyinfo,
   return value;
 }
 
+void
+x_set_pending_dnd_time (Time time)
+{
+  pending_dnd_time = time;
+}
+
 static void syms_of_xselect_for_pdumper (void);
 
 void

diff --git a/src/xterm.c b/src/xterm.c
index d29a7a122aaa1b7f8001270d0a1b274b43d7a818..77861c3fc0b8bc83d8f8b7174f3dc87a01e06ea8 100644 (file)
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -899,9 +899,14 @@ static int x_dnd_return_frame;
    `x_dnd_begin_drag_and_drop'.  */
 static struct frame *x_dnd_return_frame_object;
 
-/* The last toplevel window the mouse pointer moved over.  */
+/* The last drop target window the mouse pointer moved over.  This can
+   be different from `x_dnd_last_seen_toplevel' if that window had an
+   XdndProxy.  */
 static Window x_dnd_last_seen_window;
 
+/* The last toplevel the mouse pointer moved over.  */
+static Window x_dnd_last_seen_toplevel;
+
 /* The window where the drop happened.  Normally None, but it is set
    when something is actually dropped.  */
 static Window x_dnd_end_window;
@@ -2747,10 +2752,104 @@ x_dnd_get_wm_state_and_proto (struct x_display_info *dpyinfo,
   return rc;
 }
 
+/* From the XDND protocol specification:
+
+   Dropping on windows that do not support XDND
+
+   Since middle clicking is the universal shortcut for pasting in X,
+   one can drop data into a window that does not support XDND by:
+
+   1. After the mouse has been released to trigger the drop, obtain
+   ownership of XA_PRIMARY.
+
+   2. Send a ButtonPress event and then a ButtonRelease event to the
+   deepest subwindow containing the mouse to simulate a middle click.
+   The times for these events should be the time of the actual button
+   release +1 and +2, respectively.  These values will not be used by
+   anybody else, so one can unambiguously recognize the resulting
+   XConvertSelection() request.
+
+   3. If a request for XA_PRIMARY arrives bearing the timestamp of
+   either the ButtonPress or the ButtonRelease event, treat it as a
+   request for XdndSelection.  Note that you must use the X data
+   types instead of the MIME types in this case.  (e.g. XA_STRING
+   instead of text/plain).  */
+static void
+x_dnd_send_unsupported_drop (struct x_display_info *dpyinfo, Window target_window,
+                            int root_x, int root_y, Time before)
+{
+  XEvent event;
+  int dest_x, dest_y;
+  Window child_return, child;
+  Lisp_Object frame;
+  int i;
+
+  for (i = 0; i < x_dnd_n_targets; ++i)
+    {
+      if (x_dnd_targets[i] == XA_STRING
+         || x_dnd_targets[i] == dpyinfo->Xatom_COMPOUND_TEXT
+         || x_dnd_targets[i] == dpyinfo->Xatom_UTF8_STRING)
+       break;
+    }
+
+  if (i == x_dnd_n_targets)
+    return;
+
+  event.xbutton.type = ButtonPress;
+  event.xbutton.serial = 0;
+  event.xbutton.send_event = True;
+  event.xbutton.display = dpyinfo->display;
+  event.xbutton.root = dpyinfo->root_window;
+  event.xbutton.x_root = root_x;
+  event.xbutton.y_root = root_y;
+
+  XSETFRAME (frame, x_dnd_frame);
+
+  x_catch_errors (dpyinfo->display);
+  child = dpyinfo->root_window;
+
+  while (XTranslateCoordinates (dpyinfo->display, child,
+                               child, root_x, root_y, &dest_x,
+                               &dest_y, &child_return)
+        && child_return != None
+        && XTranslateCoordinates (dpyinfo->display, child,
+                                  child_return, root_x, root_y,
+                                  &dest_x, &dest_y, &child))
+    {
+      child = child_return;
+      root_x = dest_x;
+      root_y = dest_y;
+    }
+
+  if (child != dpyinfo->root_window)
+    {
+      x_own_selection (QPRIMARY, Qnil, frame);
+
+      event.xbutton.window = child;
+      event.xbutton.x = dest_x;
+      event.xbutton.y = dest_y;
+      event.xbutton.state = 0;
+      event.xbutton.button = 2;
+      event.xbutton.same_screen = True;
+      event.xbutton.time = before + 1;
+      event.xbutton.time = before + 2;
+
+      x_set_pending_dnd_time (before);
+
+      XSendEvent (dpyinfo->display, child,
+                 True, ButtonPressMask, &event);
+      event.xbutton.type = ButtonRelease;
+      XSendEvent (dpyinfo->display, child,
+                 True, ButtonReleaseMask, &event);
+    }
+
+  x_uncatch_errors ();
+}
+
 static Window
 x_dnd_get_target_window (struct x_display_info *dpyinfo,
                         int root_x, int root_y, int *proto_out,
-                        int *motif_out)
+                        int *motif_out, Window *toplevel_out)
 {
   Window child_return, child, dummy, proxy;
   int dest_x_return, dest_y_return, rc, proto, motif;
@@ -2767,6 +2866,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
 
   proto = -1;
   *motif_out = XM_DRAG_STYLE_NONE;
+  *toplevel_out = None;
 
   if (x_dnd_use_toplevels)
     {
@@ -2779,6 +2879,8 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
          && FRAME_X_WINDOW (x_dnd_frame) == child)
        *motif_out = XM_DRAG_STYLE_NONE;
 
+      *toplevel_out = child;
+
       if (child != None)
        {
 #ifndef USE_XCB
@@ -2808,6 +2910,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
        {
          *proto_out = -1;
          *motif_out = XM_DRAG_STYLE_NONE;
+         *toplevel_out = None;
 
          return None;
        }
@@ -2841,6 +2944,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
                          if (proto != -1)
                            {
                              *proto_out = proto;
+                             *toplevel_out = overlay_window;
                              x_uncatch_errors_after_check ();
 
                              return proxy;
@@ -2863,6 +2967,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
 
          if (proto != -1)
            {
+             *toplevel_out = dpyinfo->root_window;
              *proto_out = proto;
              return proxy;
            }
@@ -2871,6 +2976,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
       /* No toplevel was found and the overlay and root windows were
         not proxies, so return None.  */
       *proto_out = -1;
+      *toplevel_out = dpyinfo->root_window;
       return None;
     }
 
@@ -2894,21 +3000,6 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
          break;
        }
 
-      proxy = x_dnd_get_window_proxy (dpyinfo, child_return);
-
-      if (proxy != None)
-       {
-         proto = x_dnd_get_window_proto (dpyinfo, proxy);
-
-         if (proto != -1)
-           {
-             *proto_out = proto;
-
-             x_uncatch_errors ();
-             return proxy;
-           }
-       }
-
       if (child_return)
        {
          if (x_dnd_get_wm_state_and_proto (dpyinfo, child_return,
@@ -2919,11 +3010,28 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
            {
              *proto_out = proto;
              *motif_out = motif;
+             *toplevel_out = child_return;
              x_uncatch_errors ();
 
              return child_return;
            }
 
+         proxy = x_dnd_get_window_proxy (dpyinfo, child_return);
+
+         if (proxy != None)
+           {
+             proto = x_dnd_get_window_proto (dpyinfo, proxy);
+
+             if (proto != -1)
+               {
+                 *proto_out = proto;
+                 *toplevel_out = child_return;
+
+                 x_uncatch_errors ();
+                 return proxy;
+               }
+           }
+
          rc = XTranslateCoordinates (dpyinfo->display,
                                      child, child_return,
                                      dest_x_return, dest_y_return,
@@ -2934,6 +3042,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
            {
              x_uncatch_errors_after_check ();
              *proto_out = -1;
+             *toplevel_out = dpyinfo->root_window;
              return None;
            }
        }
@@ -2956,6 +3065,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
              if (proto != -1)
                {
                  *proto_out = proto;
+                 *toplevel_out = child;
                  return proxy;
                }
            }
@@ -2993,6 +3103,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
                      if (proto != -1)
                        {
                          *proto_out = proto;
+                         *toplevel_out = overlay_window;
                          x_uncatch_errors_after_check ();
 
                          return proxy;
@@ -3014,6 +3125,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
 
          if (proto != -1)
            {
+             *toplevel_out = child;
              *proto_out = proto;
              return proxy;
            }
@@ -3021,6 +3133,7 @@ x_dnd_get_target_window (struct x_display_info *dpyinfo,
     }
 
   *proto_out = x_dnd_get_window_proto (dpyinfo, child);
+  *toplevel_out = child;
   return child;
 #endif
 }
@@ -3370,6 +3483,7 @@ x_dnd_cleanup_drag_and_drop (void *frame)
 
       x_dnd_end_window = x_dnd_last_seen_window;
       x_dnd_last_seen_window = None;
+      x_dnd_last_seen_toplevel = None;
       x_dnd_in_progress = false;
       x_set_dnd_targets (NULL, 0);
     }
@@ -9236,6 +9350,7 @@ x_dnd_begin_drag_and_drop (struct frame *f, Time time, Atom xaction,
   x_dnd_in_progress = true;
   x_dnd_frame = f;
   x_dnd_last_seen_window = None;
+  x_dnd_last_seen_toplevel = None;
   x_dnd_last_protocol_version = -1;
   x_dnd_last_motif_style = XM_DRAG_STYLE_NONE;
   x_dnd_mouse_rect_target = None;
@@ -9402,6 +9517,7 @@ x_dnd_begin_drag_and_drop (struct frame *f, Time time, Atom xaction,
 
              x_dnd_end_window = x_dnd_last_seen_window;
              x_dnd_last_seen_window = None;
+             x_dnd_last_seen_toplevel = None;
              x_dnd_in_progress = false;
              x_dnd_frame = NULL;
              x_set_dnd_targets (NULL, 0);
@@ -13053,7 +13169,7 @@ x_dnd_update_state (struct x_display_info *dpyinfo, Time timestamp)
 {
   int root_x, root_y, dummy_x, dummy_y, target_proto, motif_style;
   unsigned int dummy_mask;
-  Window dummy, dummy_child, target;
+  Window dummy, dummy_child, target, toplevel;
   xm_top_level_leave_message lmsg;
   xm_top_level_enter_message emsg;
   xm_drag_motion_message dmsg;
@@ -13068,14 +13184,33 @@ x_dnd_update_state (struct x_display_info *dpyinfo, Time timestamp)
     {
       target = x_dnd_get_target_window (dpyinfo, root_x,
                                        root_y, &target_proto,
-                                       &motif_style);
+                                       &motif_style, &toplevel);
 
-      if (target != x_dnd_last_seen_window)
+      if (toplevel != x_dnd_last_seen_toplevel)
        {
-         if (target != FRAME_OUTER_WINDOW (x_dnd_frame)
+         if (toplevel != FRAME_OUTER_WINDOW (x_dnd_frame)
              && x_dnd_return_frame == 1)
            x_dnd_return_frame = 2;
 
+         if (x_dnd_return_frame == 2
+             && x_any_window_to_frame (dpyinfo, toplevel))
+           {
+             x_dnd_end_window = x_dnd_last_seen_window;
+             x_dnd_last_seen_window = None;
+             x_dnd_last_seen_toplevel = None;
+             x_dnd_in_progress = false;
+             x_dnd_return_frame_object
+               = x_any_window_to_frame (dpyinfo, toplevel);
+             x_dnd_return_frame = 3;
+             x_dnd_waiting_for_finish = false;
+             target = None;
+           }
+
+         x_dnd_last_seen_toplevel = toplevel;
+       }
+
+      if (target != x_dnd_last_seen_window)
+       {
          if (x_dnd_last_seen_window != None
              && x_dnd_last_protocol_version != -1
              && x_dnd_last_seen_window != FRAME_OUTER_WINDOW (x_dnd_frame))
@@ -13099,19 +13234,6 @@ x_dnd_update_state (struct x_display_info *dpyinfo, Time timestamp)
                                                 x_dnd_last_seen_window, &lmsg);
            }
 
-         if (x_dnd_return_frame == 2
-             && x_any_window_to_frame (dpyinfo, target))
-           {
-             x_dnd_end_window = x_dnd_last_seen_window;
-             x_dnd_last_seen_window = None;
-             x_dnd_in_progress = false;
-             x_dnd_return_frame_object
-               = x_any_window_to_frame (dpyinfo, target);
-             x_dnd_return_frame = 3;
-             x_dnd_waiting_for_finish = false;
-             target = None;
-           }
-
          x_dnd_action = None;
          x_dnd_last_seen_window = target;
          x_dnd_last_protocol_version = target_proto;
@@ -13208,6 +13330,7 @@ x_dnd_update_state (struct x_display_info *dpyinfo, Time timestamp)
 
       x_dnd_end_window = x_dnd_last_seen_window;
       x_dnd_last_seen_window = None;
+      x_dnd_last_seen_toplevel = None;
       x_dnd_in_progress = false;
       x_dnd_waiting_for_finish = false;
       x_dnd_frame = NULL;
@@ -14681,7 +14804,7 @@ handle_one_xevent (struct x_display_info *dpyinfo,
        if (x_dnd_in_progress
            && dpyinfo == FRAME_DISPLAY_INFO (x_dnd_frame))
          {
-           Window target;
+           Window target, toplevel;
            int target_proto, motif_style;
            xm_top_level_leave_message lmsg;
            xm_top_level_enter_message emsg;
@@ -14699,14 +14822,33 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                                              event->xmotion.x_root,
                                              event->xmotion.y_root,
                                              &target_proto,
-                                             &motif_style);
+                                             &motif_style, &toplevel);
 
-           if (target != x_dnd_last_seen_window)
+           if (toplevel != x_dnd_last_seen_toplevel)
              {
-               if (target != FRAME_OUTER_WINDOW (x_dnd_frame)
+               if (toplevel != FRAME_OUTER_WINDOW (x_dnd_frame)
                    && x_dnd_return_frame == 1)
                  x_dnd_return_frame = 2;
 
+               if (x_dnd_return_frame == 2
+                   && x_any_window_to_frame (dpyinfo, toplevel))
+                 {
+                   x_dnd_end_window = x_dnd_last_seen_window;
+                   x_dnd_last_seen_window = None;
+                   x_dnd_last_seen_toplevel = None;
+                   x_dnd_in_progress = false;
+                   x_dnd_return_frame_object
+                     = x_any_window_to_frame (dpyinfo, toplevel);
+                   x_dnd_return_frame = 3;
+                   x_dnd_waiting_for_finish = false;
+                   target = None;
+                 }
+
+               x_dnd_last_seen_toplevel = toplevel;
+             }
+
+           if (target != x_dnd_last_seen_window)
+             {
                if (x_dnd_last_seen_window != None
                    && x_dnd_last_protocol_version != -1
                    && x_dnd_last_seen_window != FRAME_OUTER_WINDOW (x_dnd_frame))
@@ -14751,19 +14893,6 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                      }
                  }
 
-               if (x_dnd_return_frame == 2
-                   && x_any_window_to_frame (dpyinfo, target))
-                 {
-                   x_dnd_end_window = x_dnd_last_seen_window;
-                   x_dnd_last_seen_window = None;
-                   x_dnd_in_progress = false;
-                   x_dnd_return_frame_object
-                     = x_any_window_to_frame (dpyinfo, target);
-                   x_dnd_return_frame = 3;
-                   x_dnd_waiting_for_finish = false;
-                   target = None;
-                 }
-
                x_dnd_action = None;
                x_dnd_last_seen_window = target;
                x_dnd_last_protocol_version = target_proto;
@@ -15311,11 +15440,19 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                            x_dnd_waiting_for_motif_finish = 1;
                          }
                      }
+                   else
+                     {
+                       x_set_pending_dnd_time (event->xbutton.time);
+                       x_dnd_send_unsupported_drop (dpyinfo, x_dnd_last_seen_window,
+                                                    event->xbutton.x_root, event->xbutton.y_root,
+                                                    event->xbutton.time);
+                     }
                  }
 
                x_dnd_last_protocol_version = -1;
                x_dnd_last_motif_style = XM_DRAG_STYLE_NONE;
                x_dnd_last_seen_window = None;
+               x_dnd_last_seen_toplevel = None;
                x_dnd_frame = NULL;
                x_set_dnd_targets (NULL, 0);
              }
@@ -16136,7 +16273,7 @@ handle_one_xevent (struct x_display_info *dpyinfo,
              if (x_dnd_in_progress
                  && dpyinfo == FRAME_DISPLAY_INFO (x_dnd_frame))
                {
-                 Window target;
+                 Window target, toplevel;
                  int target_proto, motif_style;
 
                  /* Sometimes the drag-and-drop operation starts with the
@@ -16151,14 +16288,34 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                                                    xev->root_x,
                                                    xev->root_y,
                                                    &target_proto,
-                                                   &motif_style);
+                                                   &motif_style,
+                                                   &toplevel);
 
-                 if (target != x_dnd_last_seen_window)
+                 if (toplevel != x_dnd_last_seen_toplevel)
                    {
-                     if (target != FRAME_OUTER_WINDOW (x_dnd_frame)
+                     if (toplevel != FRAME_OUTER_WINDOW (x_dnd_frame)
                          && x_dnd_return_frame == 1)
                        x_dnd_return_frame = 2;
 
+                     if (x_dnd_return_frame == 2
+                         && x_any_window_to_frame (dpyinfo, toplevel))
+                       {
+                         x_dnd_end_window = x_dnd_last_seen_window;
+                         x_dnd_last_seen_window = None;
+                         x_dnd_last_seen_toplevel = None;
+                         x_dnd_in_progress = false;
+                         x_dnd_return_frame_object
+                           = x_any_window_to_frame (dpyinfo, toplevel);
+                         x_dnd_return_frame = 3;
+                         x_dnd_waiting_for_finish = false;
+                         target = None;
+                       }
+
+                     x_dnd_last_seen_toplevel = toplevel;
+                   }
+
+                 if (target != x_dnd_last_seen_window)
+                   {
                      if (x_dnd_last_seen_window != None
                          && x_dnd_last_protocol_version != -1
                          && x_dnd_last_seen_window != FRAME_OUTER_WINDOW (x_dnd_frame))
@@ -16205,19 +16362,6 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                            }
                        }
 
-                     if (x_dnd_return_frame == 2
-                         && x_any_window_to_frame (dpyinfo, target))
-                       {
-                         x_dnd_end_window = x_dnd_last_seen_window;
-                         x_dnd_last_seen_window = None;
-                         x_dnd_in_progress = false;
-                         x_dnd_return_frame_object
-                           = x_any_window_to_frame (dpyinfo, target);
-                         x_dnd_return_frame = 3;
-                         x_dnd_waiting_for_finish = false;
-                         target = None;
-                       }
-
                      x_dnd_action = None;
                      x_dnd_last_seen_window = target;
                      x_dnd_last_protocol_version = target_proto;
@@ -16458,11 +16602,18 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                                  x_dnd_waiting_for_motif_finish = 1;
                                }
                            }
+                         else
+                           {
+                             x_set_pending_dnd_time (xev->time);
+                             x_dnd_send_unsupported_drop (dpyinfo, x_dnd_last_seen_window,
+                                                          xev->root_x, xev->root_y, xev->time);
+                           }
                        }
 
                      x_dnd_last_protocol_version = -1;
                      x_dnd_last_motif_style = XM_DRAG_STYLE_NONE;
                      x_dnd_last_seen_window = None;
+                     x_dnd_last_seen_toplevel = None;
                      x_dnd_frame = NULL;
                      x_set_dnd_targets (NULL, 0);
 

diff --git a/src/xterm.h b/src/xterm.h
index 5627fd23c57254f203768589cbbf8fd561925c07..79dee6a569cea30d541848a61f575c459a32a873 100644 (file)
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -1489,6 +1489,8 @@ extern void x_clipboard_manager_save_all (void);
 
 extern Lisp_Object x_timestamp_for_selection (struct x_display_info *,
                                              Lisp_Object);
+extern void x_set_pending_dnd_time (Time);
+extern void x_own_selection (Lisp_Object, Lisp_Object, Lisp_Object);
 
 #ifdef USE_GTK
 extern bool xg_set_icon (struct frame *, Lisp_Object);