From 8b6f6db0f5faddc970a7867aecdb03f3cde5fa78 Mon Sep 17 00:00:00 2001
From: Dan Gudmundsson <dgud@erlang.org>
Date: Fri, 2 Dec 2011 16:26:45 +0100
Subject: [wx] Avoid deadlock in handle_sync_event

Avoid sending cb messages to the wx_object, since it may deadlock.
Instead send it to the wxe_server which reads the state from the wx_object's
process_dictionary.

Ugly but it's the only way I can avoid the deadlock.
---
 lib/wx/test/wx_obj_test.erl | 86 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 lib/wx/test/wx_obj_test.erl

(limited to 'lib/wx/test/wx_obj_test.erl')

diff --git a/lib/wx/test/wx_obj_test.erl b/lib/wx/test/wx_obj_test.erl
new file mode 100644
index 0000000000..b4d7640c7e
--- /dev/null
+++ b/lib/wx/test/wx_obj_test.erl
@@ -0,0 +1,86 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2011. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+-module(wx_obj_test).
+-include_lib("wx/include/wx.hrl").
+
+-export([start/1]).
+
+%% wx_object callbacks
+-export([init/1, handle_info/2, terminate/2, code_change/3, handle_call/3,
+	 handle_sync_event/3, handle_event/2, handle_cast/2]).
+
+-record(state, {frame, panel, opts}).
+
+start(Opts) ->
+    wx_object:start_link(?MODULE, [{parent, self()}, Opts], []).
+
+init(Opts) ->
+    put(parent_pid, proplists:get_value(parent, Opts)),
+    Frame = wxFrame:new(wx:null(), ?wxID_ANY, "Test wx_object", [{size, {500, 400}}]),
+    Sz = wxBoxSizer:new(?wxHORIZONTAL),
+    Panel = wxPanel:new(Frame),
+    wxSizer:add(Sz, Panel, [{flag, ?wxEXPAND}, {proportion, 1}]),
+    wxPanel:connect(Panel, size, [{skip, true}]),
+    wxPanel:connect(Panel, paint, [callback, {userData, proplists:get_value(parent, Opts)}]),
+    wxWindow:show(Frame),
+    {Frame, #state{frame=Frame, panel=Panel, opts=Opts}}.
+
+handle_sync_event(Event = #wx{obj=Panel}, WxEvent, #state{opts=Opts}) ->
+    DC=wxPaintDC:new(Panel),  %% We must create & destroy paintDC, or call wxEvent:skip(WxEvent))
+    wxPaintDC:destroy(DC),    %% in sync_event. Otherwise wx on windows keeps sending the events.
+    Pid = proplists:get_value(parent, Opts),
+    true = is_pid(Pid),
+    Pid ! {sync_event, Event, WxEvent},
+    ok.
+
+handle_event(Event, State = #state{opts=Opts}) ->
+    Pid = proplists:get_value(parent, Opts),
+    Pid ! {event, Event},
+    {noreply, State}.
+
+handle_call(What, From, State) when is_function(What) ->
+    Result = What(State),
+    {reply, {call, Result, From}, State};
+handle_call(What, From, State) ->
+    {reply, {call, What, From}, State}.
+
+handle_cast(What, State = #state{opts=Opts})  when is_function(What) ->
+    Result = What(State),
+    Pid = proplists:get_value(parent, Opts),
+    Pid ! {cast, Result},
+    {noreply, State};
+
+handle_cast(What, State = #state{opts=Opts}) ->
+    Pid = proplists:get_value(parent, Opts),
+    Pid ! {cast, What},
+    {noreply, State}.
+
+handle_info(What, State = #state{opts=Opts}) ->
+    Pid = proplists:get_value(parent, Opts),
+    Pid ! {info, What},
+    {noreply, State}.
+
+terminate(What, #state{opts=Opts}) ->
+    Pid = proplists:get_value(parent, Opts),
+    Pid ! {terminate, What},
+    ok.
+
+code_change(Ver1, Ver2, State = #state{opts=Opts}) ->
+    Pid = proplists:get_value(parent, Opts),
+    Pid ! {code_change, Ver1, Ver2},
+    State.
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