From a19fdb717bc320a41092195a97bbd2281ae2472e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Chmielowski?= <pchmielowski@process-one.net>
Date: Tue, 18 Feb 2020 15:02:14 +0100
Subject: [PATCH] Do read piefxis file fully before starting processing
 included file

Previous method of processing files, could lead to mixing events generated
by parsers for multiple files, where we could get in inconsistant state.

After this change we gather all events generated by parser for single file,
before we start parsing any included file.

This fixes issue #3166
---
 src/ejabberd_piefxis.erl | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/ejabberd_piefxis.erl b/src/ejabberd_piefxis.erl
index e4c74177c..737ed502f 100644
--- a/src/ejabberd_piefxis.erl
+++ b/src/ejabberd_piefxis.erl
@@ -296,17 +296,26 @@ process(#state{xml_stream_state = XMLStreamState, fd = Fd} = State) ->
     end.
 
 process_els(State) ->
+    Els = gather_els(State, []),
+    process_els(State, lists:reverse(Els)).
+
+gather_els(State, List) ->
     receive
         {'$gen_event', El} ->
-            case process_el(El, State) of
-                {ok, NewState} ->
-                    process_els(NewState);
-                Err ->
-                    Err
-            end
+            gather_els(State, [El | List])
     after 0 ->
-            {ok, State}
-    end.
+        List
+end.
+
+process_els(State, [El | Tail]) ->
+    case process_el(El, State) of
+        {ok, NewState} ->
+            process_els(NewState, Tail);
+        Err ->
+            Err
+    end;
+process_els(State, []) ->
+    {ok, State}.
 
 process_el({xmlstreamstart, <<"server-data">>, Attrs}, State) ->
     case fxml:get_attr_s(<<"xmlns">>, Attrs) of