Improve drag-and-drop emulation time handling

* src/xselect.c (x_handle_selection_request): Use
display-specific pending DND time.
(x_set_pending_dnd_time): Delete function.
* src/xterm.c (x_dnd_do_unsupported_drop, handle_one_xevent):
Set dpyinfo->pending_dnd_time instead.
* src/xterm.h (struct x_display_info): New field
`pending_dnd_time'.  Make handling pending drops
display-specific to avoid interference when there are multiple
displays.

3 files changed, 32 insertions, 49 deletions

diff --git a/src/xselect.c b/src/xselect.c
index d1b6d454abd..80db0d1fe2a 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -40,8 +40,6 @@ 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;
 
@@ -265,7 +263,7 @@ x_atom_to_symbol (struct x_display_info *dpyinfo, Atom atom)
    TIMESTAMP should be the timestamp where selection ownership will be
    assumed.
    DND_DATA is the local value that will be used for selection requests
-   with `pending_dnd_time'.
+   with `dpyinfo->pending_dnd_time'.
    Update the Vselection_alist so that we can reply to later requests for
    our selection.  */
 
@@ -855,8 +853,11 @@ x_handle_selection_request (struct selection_input_event *event)
 
   /* 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)
+  if (dpyinfo->pending_dnd_time
+      && ((SELECTION_EVENT_TIME (event)
+           == dpyinfo->pending_dnd_time + 1)
+          || (SELECTION_EVENT_TIME (event)
+              == dpyinfo->pending_dnd_time + 2)))
     use_alternate = true;
 
   block_input ();
@@ -2884,12 +2885,6 @@ 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 1afb8adcfee..d9485980fea 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -3873,8 +3873,10 @@ x_dnd_do_unsupported_drop (struct x_display_info *dpyinfo,
          && child_return != None)
     child = child_return;
 
+  x_uncatch_errors ();
+
   if (!CONSP (value))
-    goto cancel;
+    return;
 
   current_value = assq_no_quit (QPRIMARY,
                                 dpyinfo->terminal->Vselection_alist);
@@ -3891,9 +3893,7 @@ x_dnd_do_unsupported_drop (struct x_display_info *dpyinfo,
      from generating events that will insert something else.  */
 
   if (owner != FRAME_X_WINDOW (f))
-    goto cancel;
-
-  x_uncatch_errors ();
+    return;
 
   event.xbutton.window = child;
   event.xbutton.subwindow = None;
@@ -3903,7 +3903,7 @@ x_dnd_do_unsupported_drop (struct x_display_info *dpyinfo,
   event.xbutton.button = 2;
   event.xbutton.same_screen = True;
 
-  x_set_pending_dnd_time (before);
+  dpyinfo->pending_dnd_time = before;
 
   event.xbutton.type = ButtonPress;
   event.xbutton.time = before + 1;
@@ -3924,9 +3924,6 @@ x_dnd_do_unsupported_drop (struct x_display_info *dpyinfo,
   x_dnd_action_symbol = QXdndActionPrivate;
 
   return;
-
- cancel:
-  x_uncatch_errors ();
 }
 
 static void
@@ -18934,23 +18931,17 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                               }
                           }
                         else
-                          {
-                            x_set_pending_dnd_time (event->xbutton.time);
-                            x_dnd_send_unsupported_drop (dpyinfo, (x_dnd_last_seen_toplevel != None
-                                                                   ? x_dnd_last_seen_toplevel
-                                                                   : x_dnd_last_seen_window),
-                                                         event->xbutton.x_root, event->xbutton.y_root,
-                                                         event->xbutton.time);
-                          }
+                          x_dnd_send_unsupported_drop (dpyinfo, (x_dnd_last_seen_toplevel != None
+                                                                 ? x_dnd_last_seen_toplevel
+                                                                 : x_dnd_last_seen_window),
+                                                       event->xbutton.x_root, event->xbutton.y_root,
+                                                       event->xbutton.time);
                       }
                     else if (x_dnd_last_seen_toplevel != None)
-                      {
-                        x_set_pending_dnd_time (event->xbutton.time);
-                        x_dnd_send_unsupported_drop (dpyinfo, x_dnd_last_seen_toplevel,
-                                                     event->xbutton.x_root,
-                                                     event->xbutton.y_root,
-                                                     event->xbutton.time);
-                      }
+                      x_dnd_send_unsupported_drop (dpyinfo, x_dnd_last_seen_toplevel,
+                                                   event->xbutton.x_root,
+                                                   event->xbutton.y_root,
+                                                   event->xbutton.time);
 
 
                     x_dnd_last_protocol_version = -1;
@@ -20352,22 +20343,16 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                                     }
                                 }
                               else
-                                {
-                                  x_set_pending_dnd_time (xev->time);
-                                  x_dnd_send_unsupported_drop (dpyinfo, (x_dnd_last_seen_toplevel != None
-                                                                         ? x_dnd_last_seen_toplevel
-                                                                         : x_dnd_last_seen_window),
-                                                               xev->root_x, xev->root_y, xev->time);
-                                }
+                                x_dnd_send_unsupported_drop (dpyinfo, (x_dnd_last_seen_toplevel != None
+                                                                       ? x_dnd_last_seen_toplevel
+                                                                       : x_dnd_last_seen_window),
+                                                             xev->root_x, xev->root_y, xev->time);
                             }
                           else if (x_dnd_last_seen_toplevel != None)
-                            {
-                              x_set_pending_dnd_time (xev->time);
-                              x_dnd_send_unsupported_drop (dpyinfo,
-                                                           x_dnd_last_seen_toplevel,
-                                                           xev->root_x, xev->root_y,
-                                                           xev->time);
-                            }
+                            x_dnd_send_unsupported_drop (dpyinfo,
+                                                         x_dnd_last_seen_toplevel,
+                                                         xev->root_x, xev->root_y,
+                                                         xev->time);
 
                           x_dnd_last_protocol_version = -1;
                           x_dnd_last_motif_style = XM_DRAG_STYLE_NONE;
diff --git a/src/xterm.h b/src/xterm.h
index 6684d7839f3..92e88bb50fa 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -765,6 +765,10 @@ struct x_display_info
 
   /* Pointer to the next request in `failable_requests'.  */
   struct x_failable_request *next_failable_request;
+
+  /* The pending drag-and-drop time for middle-click based
+     drag-and-drop emulation.  */
+  Time pending_dnd_time;
 };
 
 #ifdef HAVE_X_I18N
@@ -1617,7 +1621,6 @@ 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,
                              Lisp_Object, Time);
 extern Atom x_intern_cached_atom (struct x_display_info *, const char *,