Enable silent start of wx

Add {silent_start, boolean()} option to wx:new/1 in order to be able
to suppress error messages during startup of wx.

4 files changed, 57 insertions, 37 deletions

diff --git a/lib/wx/src/wx.erl b/lib/wx/src/wx.erl
index 7d62305048..2a4b18d101 100644
--- a/lib/wx/src/wx.erl
+++ b/lib/wx/src/wx.erl
@@ -102,12 +102,18 @@ new() ->
 
 %% @doc Starts a wx server.
 %% Option may be {debug, Level}, see debug/1.
--spec new([Option]) -> wx_object() when Option :: {debug, list() | atom()}.
+%% Or {silent_start, Bool}, which causes error messages at startup to
+%% be suppressed. The latter can be used as a silent test of whether
+%% wx is properly installed or not.
+-spec new([Option]) -> wx_object() when Option :: {debug, list() | atom()} |
+                                                  {silent_start, boolean()}.
 new(Options) when is_list(Options) ->
-    #wx_env{port=Port} = wxe_server:start(),
-    put(opengl_port, Port),
     Debug = proplists:get_value(debug, Options, 0),
-    debug(Debug),
+    SilentStart = proplists:get_value(silent_start, Options, false),
+    Level = calc_level(Debug),
+    #wx_env{port=Port} = wxe_server:start(SilentStart andalso Level =:= 0),
+    put(opengl_port, Port),
+    set_debug(Level),
     null().
 
 %% @doc Stops a wx server.
@@ -282,13 +288,16 @@ release_memory(Bin) when is_binary(Bin) ->
 -spec debug(Level | [Level]) -> ok
      when Level :: none | verbose | trace | driver | integer().
 
-debug(none) -> debug(0);
-debug(verbose) -> debug(1);
-debug(trace) -> debug(2);
-debug(driver) -> debug(16);
-debug([]) -> debug(0);
+debug(Debug) ->
+    Level = calc_level(Debug),
+    set_debug(Level).
 
-debug(List) when is_list(List) ->
+calc_level(none) -> calc_level(0);
+calc_level(verbose) -> calc_level(1);
+calc_level(trace) -> calc_level(2);
+calc_level(driver) -> calc_level(16);
+calc_level([]) -> calc_level(0);
+calc_level(List) when is_list(List) ->
     {Drv,Erl} =
 	lists:foldl(fun(verbose, {Drv,_Erl}) ->
 			    {Drv,1};
@@ -297,8 +306,11 @@ debug(List) when is_list(List) ->
 		       (driver, {_Drv,Erl}) ->
 			    {16, Erl}
 		    end, {0,0}, List),
-    debug(Drv + Erl);
-debug(Level) when is_integer(Level) ->
+    Drv + Erl;
+calc_level(Level) when is_integer(Level) ->
+    Level.
+
+set_debug(Level) when is_integer(Level) ->
     case get(?WXE_IDENTIFIER) of
 	undefined -> erlang:error({wxe,unknown_port});
 	#wx_env{debug=Old} when Old =:= Level -> ok;
diff --git a/lib/wx/src/wxe_master.erl b/lib/wx/src/wxe_master.erl
index ac6e4a56e6..b98a7c793e 100644
--- a/lib/wx/src/wxe_master.erl
+++ b/lib/wx/src/wxe_master.erl
@@ -28,7 +28,7 @@
 -behaviour(gen_server).
 
 %% API
--export([start/0, init_port/0, init_opengl/0]).
+-export([start/1, init_port/1, init_opengl/0]).
 
 %% gen_server callbacks
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
@@ -47,20 +47,20 @@
 %% API
 %%====================================================================
 %%--------------------------------------------------------------------
-%% Function: start_link() -> {ok,Pid} | ignore | {error,Error}
+%% Function: start(SilentStart) -> {ok,Pid} | ignore | {error,Error}
 %% Description: Starts the server
 %%--------------------------------------------------------------------
-start() ->
-    gen_server:start({local, ?MODULE}, ?MODULE, [], []).
+start(SilentStart) ->
+    gen_server:start({local, ?MODULE}, ?MODULE, [SilentStart], []).
 
 %%--------------------------------------------------------------------
-%% Function: init_port() -> {UserPort,CallBackPort} | error(Error)
+%% Function: init_port(SilentStart) -> {UserPort,CallBackPort} | error(Error)
 %% Description: Creates the port
 %%--------------------------------------------------------------------
-init_port() ->
+init_port(SilentStart) ->
     case whereis(?MODULE) of
 	undefined ->
-	    case start() of
+	    case start(SilentStart) of
 		{ok,Pid} -> Pid;
 		{error,{already_started,Pid}} -> Pid;
 		{error, {Reason,Stack}} ->
@@ -93,14 +93,17 @@ init_opengl() ->
 %%                         {stop, Reason}
 %% Description: Initiates the server
 %%--------------------------------------------------------------------
-init([]) ->
+init([SilentStart]) ->
     DriverName = ?DRIVER,
-    PrivDir = wxe_util:priv_dir(?DRIVER),
+    PrivDir = wxe_util:priv_dir(?DRIVER, SilentStart),
     erlang:group_leader(whereis(init), self()),
     case catch erlang:system_info(smp_support) of
 	true -> ok;
 	_ -> 
-	    error_logger:format("WX ERROR: SMP emulator required (start with erl -smp)", []),
+	    wxe_util:opt_error_log(SilentStart,
+                                   "WX ERROR: SMP emulator required"
+                                   " (start with erl -smp)",
+                                   []),
 	    erlang:error(not_smp)
     end,
 
@@ -114,7 +117,9 @@ init([]) ->
     case erl_ddll:load_driver(PrivDir,DriverName) of
 	ok -> ok;
 	{error, What} -> 
-	    error_logger:format("WX Failed loading ~p@~p ~n", [DriverName,PrivDir]),
+	    wxe_util:opt_error_log(SilentStart,
+                                   "WX Failed loading ~p@~p ~n",
+                                   [DriverName,PrivDir]),
 	    Str = erl_ddll:format_error(What),
 	    erlang:error({load_driver,Str})
     end,
@@ -210,4 +215,3 @@ debug_ping(Port) ->
     _R = (catch erlang:port_call(Port, 0, [])),
 %%    io:format("Erlang ping ~p ~n", [_R]),
     debug_ping(Port).
-
diff --git a/lib/wx/src/wxe_server.erl b/lib/wx/src/wxe_server.erl
index 6e982c97f6..689fe16a70 100644
--- a/lib/wx/src/wxe_server.erl
+++ b/lib/wx/src/wxe_server.erl
@@ -29,7 +29,7 @@
 -behaviour(gen_server).
 
 %% API
--export([start/0, stop/0, register_me/1, set_debug/2, invoke_callback/1]).
+-export([start/1, stop/0, register_me/1, set_debug/2, invoke_callback/1]).
 
 %% gen_server callbacks
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
@@ -49,13 +49,13 @@
 %% API
 %%====================================================================
 %%--------------------------------------------------------------------
-%% Function: start() -> #wx_env{}
+%% Function: start(SilentStart) -> #wx_env{}
 %% Description: Starts the server
 %%--------------------------------------------------------------------
-start() ->
+start(SilentStart) ->
     case get(?WXE_IDENTIFIER) of
 	undefined ->
-	    case gen_server:start(?MODULE, [], []) of
+	    case gen_server:start(?MODULE, [SilentStart], []) of
 		{ok, Pid}  ->
 		    {ok, Port} = gen_server:call(Pid, get_port, infinity),
 		    wx:set_env(Env = #wx_env{port=Port,sv=Pid}),
@@ -69,7 +69,7 @@ start() ->
 		    Env;
 		false ->  %% Ok we got an old wx env, someone forgot
 		    erase(?WXE_IDENTIFIER),  %% to call wx:destroy()
-		    start()
+		    start(SilentStart)
 	    end
     end.
 
@@ -88,8 +88,8 @@ set_debug(Pid, Level) ->
 %% gen_server callbacks
 %%====================================================================
 
-init([]) ->
-    {Port,CBPort} = wxe_master:init_port(),
+init([SilentStart]) ->
+    {Port,CBPort} = wxe_master:init_port(SilentStart),
     put(?WXE_IDENTIFIER, #wx_env{port=Port,sv=self()}),
     {ok,#state{port=Port, cb_port=CBPort,
 	       users=gb_trees:empty(), cb=gb_trees:empty(), cb_cnt=1}}.
diff --git a/lib/wx/src/wxe_util.erl b/lib/wx/src/wxe_util.erl
index 02bca62486..3022b7f3f2 100644
--- a/lib/wx/src/wxe_util.erl
+++ b/lib/wx/src/wxe_util.erl
@@ -32,7 +32,7 @@
 	 get_const/1,colour_bin/1,datetime_bin/1,
 	 to_bool/1,from_bool/1]).
 
--export([wxgl_dl/0, priv_dir/1]).
+-export([wxgl_dl/0, priv_dir/2, opt_error_log/3]).
 
 -include("wxe.hrl").
 
@@ -205,7 +205,7 @@ check_previous() ->
 
 wxgl_dl() ->
     DynLib0 = "erl_gl",
-    PrivDir = priv_dir(DynLib0),
+    PrivDir = priv_dir(DynLib0, false),
     DynLib = case os:type() of
 		 {win32,_} ->
 		     DynLib0 ++ ".dll";
@@ -214,7 +214,7 @@ wxgl_dl() ->
 	     end,
     filename:join(PrivDir, DynLib).
 
-priv_dir(Driver0) ->
+priv_dir(Driver0, Silent) ->
     {file, Path} = code:is_loaded(?MODULE),
     Priv = case filelib:is_regular(Path) of
 	       true ->
@@ -229,13 +229,13 @@ priv_dir(Driver0) ->
 		 _ ->
 		     Driver0 ++ ".so"
 	     end,
-
     case file:read_file_info(filename:join(Priv, Driver)) of
 	{ok, _} ->
 	    Priv;
 	{error, _} ->
-	    error_logger:format("ERROR: Could not find \'~s\' in: ~s~n",
-				[Driver, Priv]),
+	    opt_error_log(Silent,
+                          "ERROR: Could not find \'~s\' in: ~s~n",
+                          [Driver, Priv]),
 	    erlang:error({load_driver, "No driver found"})
     end.
 
@@ -244,3 +244,7 @@ strip(Src, Src) ->
 strip([H|R], Src) ->
     [H| strip(R, Src)].
 
+opt_error_log(false, Format, Args) ->
+    error_logger:format(Format, Args);
+opt_error_log(true, _Format, _Args) ->
+    ok.