Fix hangs when x-get-selection is called inside a popup menu

* src/xselect.c (wait_for_property_change):
(x_get_foreign_selection): Use `x_wait_for_cell_change' if input
is blocked.  (bug#22214)
* src/xterm.c (x_wait_for_cell_change): New function.
* src/xterm.h: Update prototypes.

1 files changed, 18 insertions, 4 deletions

diff --git a/src/xselect.c b/src/xselect.c
index bfd081b1e28..a4148735945 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -1148,8 +1148,13 @@ wait_for_property_change (struct prop_location *location)
       intmax_t secs = timeout / 1000;
       int nsecs = (timeout % 1000) * 1000000;
       TRACE2 ("  Waiting %"PRIdMAX" secs, %d nsecs", secs, nsecs);
-      wait_reading_process_output (secs, nsecs, 0, false,
-                                   property_change_reply, NULL, 0);
+
+      if (!input_blocked_p ())
+        wait_reading_process_output (secs, nsecs, 0, false,
+                                     property_change_reply, NULL, 0);
+      else
+        x_wait_for_cell_change (property_change_reply,
+                                make_timespec (secs, nsecs));
 
       if (NILP (XCAR (property_change_reply)))
         {
@@ -1256,8 +1261,17 @@ x_get_foreign_selection (Lisp_Object selection_symbol, Lisp_Object target_type,
   intmax_t secs = timeout / 1000;
   int nsecs = (timeout % 1000) * 1000000;
   TRACE1 ("  Start waiting %"PRIdMAX" secs for SelectionNotify", secs);
-  wait_reading_process_output (secs, nsecs, 0, false,
-                               reading_selection_reply, NULL, 0);
+  /* This function can be called with input blocked inside Xt or GTK
+     timeouts run inside popup menus, so use a function that works
+     when input is blocked.  Prefer wait_reading_process_output
+     otherwise, or the toolkit might not get some events.
+     (bug#22214) */
+  if (!input_blocked_p ())
+    wait_reading_process_output (secs, nsecs, 0, false,
+                                 reading_selection_reply, NULL, 0);
+  else
+    x_wait_for_cell_change (reading_selection_reply,
+                            make_timespec (secs, nsecs));
   TRACE1 ("  Got event = %d", !NILP (XCAR (reading_selection_reply)));
 
   if (NILP (XCAR (reading_selection_reply)))