Do not delete the MULTIPLE property after reading it

Per the ICCCM spec:

> The requestor should delete [...] the property specified in the
> MULTIPLE request when it has copied all the data.

We are not the requestor, so we should not be deleting this property
(which is what x_get_window_property_as_lisp_data does).  The property
needs to remain available as the requestor will generally want to read
it back to see which conversions succeeded or not.

* src/xselect.c (x_get_window_property_as_lisp_data): Add flag which
skips deleting the read property, or handling INCR (which does not
make sense for MULTIPLE).
(x_handle_selection_request): Enable the flag.

1 files changed, 16 insertions, 10 deletions

diff --git a/src/xselect.c b/src/xselect.c
index cfe028a1696..537be2ddd54 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -52,7 +52,7 @@ static void unexpect_property_change (struct prop_location *);
 static void wait_for_property_change (struct prop_location *);
 static Lisp_Object x_get_window_property_as_lisp_data (struct x_display_info *,
                                                        Window, Atom,
-                                                       Lisp_Object, Atom);
+                                                       Lisp_Object, Atom, bool);
 static Lisp_Object selection_data_to_lisp_data (struct x_display_info *,
                                                 const unsigned char *,
                                                 ptrdiff_t, Atom, int);
@@ -799,7 +799,7 @@ x_handle_selection_request (struct selection_input_event *event)
       if (property == None) goto DONE;
       multprop
         = x_get_window_property_as_lisp_data (dpyinfo, requestor, property,
-                                              QMULTIPLE, selection);
+                                              QMULTIPLE, selection, true);
 
       if (!VECTORP (multprop) || ASIZE (multprop) % 2)
         goto DONE;
@@ -1210,7 +1210,7 @@ x_get_foreign_selection (Lisp_Object selection_symbol, Lisp_Object target_type,
   return
     x_get_window_property_as_lisp_data (dpyinfo, requestor_window,
                                         target_property, target_type,
-                                        selection_atom);
+                                        selection_atom, false);
 }
 
 /* Subroutines of x_get_window_property_as_lisp_data */
@@ -1461,7 +1461,8 @@ static Lisp_Object
 x_get_window_property_as_lisp_data (struct x_display_info *dpyinfo,
                                     Window window, Atom property,
                                     Lisp_Object target_type,
-                                    Atom selection_atom)
+                                    Atom selection_atom,
+                                    bool for_multiple)
 {
   Atom actual_type;
   int actual_format;
@@ -1477,6 +1478,8 @@ x_get_window_property_as_lisp_data (struct x_display_info *dpyinfo,
                          &actual_type, &actual_format, &actual_size);
   if (! data)
     {
+      if (for_multiple)
+        return Qnil;
       block_input ();
       bool there_is_a_selection_owner
         = XGetSelectionOwner (display, selection_atom) != 0;
@@ -1499,7 +1502,7 @@ x_get_window_property_as_lisp_data (struct x_display_info *dpyinfo,
         }
     }
 
-  if (actual_type == dpyinfo->Xatom_INCR)
+  if (!for_multiple && actual_type == dpyinfo->Xatom_INCR)
     {
       /* That wasn't really the data, just the beginning.  */
 
@@ -1515,11 +1518,14 @@ x_get_window_property_as_lisp_data (struct x_display_info *dpyinfo,
                                      &actual_size);
     }
 
-  block_input ();
-  TRACE1 ("  Delete property %s", XGetAtomName (display, property));
-  XDeleteProperty (display, window, property);
-  XFlush (display);
-  unblock_input ();
+  if (!for_multiple)
+    {
+      block_input ();
+      TRACE1 ("  Delete property %s", XGetAtomName (display, property));
+      XDeleteProperty (display, window, property);
+      XFlush (display);
+      unblock_input ();
+    }
 
   /* It's been read.  Now convert it to a lisp object in some semi-rational
      manner.  */