%% ``Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%%
%% $Id: asn1rt_driver_handler.erl,v 1.1 2008/12/17 09:53:30 mikpe Exp $
%%
-module(asn1rt_driver_handler).
-export([init/1,load_driver/0,unload_driver/0]).
load_driver() ->
spawn(asn1rt_driver_handler, init, [self()]).
init(From) ->
Port=
case load_driver("asn1_erl_drv") of
ok ->
open_named_port(From);
already_done ->
From ! driver_ready;
Error -> % if erl_ddll:load_driver fails
erl_ddll:unload_driver("asn1_erl_drv"),
From ! Error
end,
register_and_loop(Port).
load_driver(DriverName) ->
case is_driver_loaded(DriverName) of
false ->
Dir = filename:join([code:priv_dir(asn1),"lib"]),
erl_ddll:load_driver(Dir,DriverName);
true ->
ok
end.
is_driver_loaded(_Name) ->
case whereis(asn1_driver_owner) of
undefined ->
false;
_ ->
true
end.
open_named_port(From) ->
case is_port_open(drv_complete) of
false ->
case catch open_port({spawn,"asn1_erl_drv"},[]) of
{'EXIT',Reason} ->
From ! {port_error,Reason};
Port ->
register(drv_complete,Port),
From ! driver_ready,
Port
end;
_ ->
From ! driver_ready,
ok
end.
is_port_open(Name) ->
case whereis(Name) of
Port when port(Port) ->
true;
_ -> false
end.
register_and_loop(Port) when port(Port) ->
register(asn1_driver_owner,self()),
loop();
register_and_loop(_) ->
ok.
loop() ->
receive
unload ->
case whereis(drv_complete) of
Port when port(Port) ->
port_close(Port);
_ -> ok
end,
erl_ddll:unload_driver("asn1_erl_drv"),
ok;
_ ->
loop()
end.
unload_driver() ->
case whereis(asn1_driver_owner) of
Pid when pid(Pid) ->
Pid ! unload,
ok;
_ ->
ok
end.
