wx_objects: Fix calls to unexported gen_server:print_event/3

In code copied (and modified) from the gen_server module, there
are references to the gen_server:print_event/3 function, which is
not exported.

We could export print_event/3 from the gen_server, but in that
case we must promise to keep the function and keep it compatible
in the future. Since the function is small and wx_object already
contains a lot of code copied from gen_server, let's copy the
code for print_event/3 too.

(Thanks to Kostis Sagonas. This old bug was exposed by a patch
by Kostis that replaced "tuple funs" with real funs.)

1 files changed, 35 insertions, 11 deletions

diff --git a/lib/wx/src/wx_object.erl b/lib/wx/src/wx_object.erl
index 1f0b7922a0..83f9219484 100644
--- a/lib/wx/src/wx_object.erl
+++ b/lib/wx/src/wx_object.erl
@@ -321,7 +321,8 @@ loop(Parent, Name, State, Mod, Time, Debug) ->
 	_Msg when Debug =:= [] ->
 	    handle_msg(Msg, Parent, Name, State, Mod);
 	_Msg ->
-	    Debug1 = sys:handle_debug(Debug, {gen_server, print_event}, Name, {in, Msg}),
+	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
+				      Name, {in, Msg}),
 	    handle_msg(Msg, Parent, Name, State, Mod, Debug1)
     end.
 
@@ -410,12 +411,12 @@ handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, Debug) ->
 	    Debug1 = reply(Name, From, Reply, NState, Debug),
 	    loop(Parent, Name, NState, Mod, Time1, Debug1);
 	{noreply, NState} ->
-	    Debug1 = sys:handle_debug(Debug, {gen_server, print_event}, Name,
-				      {noreply, NState}),
+	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
+				      Name, {noreply, NState}),
 	    loop(Parent, Name, NState, Mod, infinity, Debug1);
 	{noreply, NState, Time1} ->
-	    Debug1 = sys:handle_debug(Debug, {gen_server, print_event}, Name,
-				      {noreply, NState}),
+	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
+				      Name, {noreply, NState}),
 	    loop(Parent, Name, NState, Mod, Time1, Debug1);
 	{stop, Reason, Reply, NState} ->
 	    {'EXIT', R} = 
@@ -437,12 +438,12 @@ handle_no_reply({noreply, NState}, Parent, Name, _Msg, Mod, _State, []) ->
 handle_no_reply({noreply, NState, Time1}, Parent, Name, _Msg, Mod, _State, []) ->
     loop(Parent, Name, NState, Mod, Time1, []);
 handle_no_reply({noreply, NState}, Parent, Name, _Msg, Mod, _State, Debug) ->
-    Debug1 = sys:handle_debug(Debug, {gen_server, print_event}, Name,
-			      {noreply, NState}),
+    Debug1 = sys:handle_debug(Debug, fun print_event/3,
+			      Name, {noreply, NState}),
     loop(Parent, Name, NState, Mod, infinity, Debug1);
 handle_no_reply({noreply, NState, Time1}, Parent, Name, _Msg, Mod, _State, Debug) ->
-    Debug1 = sys:handle_debug(Debug, {gen_server, print_event}, Name,
-			      {noreply, NState}),
+    Debug1 = sys:handle_debug(Debug, fun print_event/3,
+			      Name, {noreply, NState}),
     loop(Parent, Name, NState, Mod, Time1, Debug1);
 handle_no_reply(Reply, _Parent, Name, Msg, Mod, State, Debug) ->
     handle_common_reply(Reply, Name, Msg, Mod, State,Debug).
@@ -462,8 +463,8 @@ handle_common_reply(Reply, Name, Msg, Mod, State, Debug) ->
 %% @hidden
 reply(Name, {To, Tag}, Reply, State, Debug) ->
     reply({To, Tag}, Reply),
-    sys:handle_debug(Debug, {gen_server, print_event}, Name, 
-		     {out, Reply, To, State} ).
+    sys:handle_debug(Debug, fun print_event/3,
+		     Name, {out, Reply, To, State}).
 
 
 %%-----------------------------------------------------------------
@@ -485,6 +486,29 @@ system_code_change([Name, State, Mod, Time], _Module, OldVsn, Extra) ->
 	Else -> Else
     end.
 
+%%-----------------------------------------------------------------
+%% Format debug messages.  Print them as the call-back module sees
+%% them, not as the real erlang messages.  Use trace for that.
+%%-----------------------------------------------------------------
+print_event(Dev, {in, Msg}, Name) ->
+    case Msg of
+	{'$gen_call', {From, _Tag}, Call} ->
+	    io:format(Dev, "*DBG* ~p got call ~p from ~w~n",
+		      [Name, Call, From]);
+	{'$gen_cast', Cast} ->
+	    io:format(Dev, "*DBG* ~p got cast ~p~n",
+		      [Name, Cast]);
+	_ ->
+	    io:format(Dev, "*DBG* ~p got ~p~n", [Name, Msg])
+    end;
+print_event(Dev, {out, Msg, To, State}, Name) ->
+    io:format(Dev, "*DBG* ~p sent ~p to ~w, new state ~w~n",
+	      [Name, Msg, To, State]);
+print_event(Dev, {noreply, State}, Name) ->
+    io:format(Dev, "*DBG* ~p new state ~w~n", [Name, State]);
+print_event(Dev, Event, Name) ->
+    io:format(Dev, "*DBG* ~p dbg  ~p~n", [Name, Event]).
+
 %%% ---------------------------------------------------
 %%% Terminate the server.
 %%% ---------------------------------------------------