src/dubbo_codec.erl

%%%-------------------------------------------------------------------
%%% @author dlive
%%% @copyright (C) 2016, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 20. 十月 2016 下午6:21
%%%-------------------------------------------------------------------
-module(dubbo_codec).
-author("dlive").

-include("dubbo.hrl").
-include("hessian.hrl").

-ifdef(TEST).
-compile(export_all).
-endif.
%% API
-export([encode_request/1,encode_response/1]).

-export([decode_header/1]).
-export([decode_response/2]).
-export([decode_request/2]).



-spec encode_request(#dubbo_request{})->{ok,binary()} | {error,term()}.
encode_request(Request)->
    {ok,RequestData} = encode_request_data(Request#dubbo_request.serialize_type,Request),
    Size = byte_size(RequestData),
    Header = encode_header(Request,Size,0),
    RequestContent = <<Header/binary,RequestData/binary>>,
    {ok,RequestContent}.

encode_header(Request,DataLen,RequestState)->
    Header2=-128 bor Request#dubbo_request.serialize_type,
    Header21=case Request#dubbo_request.is_twoway of
        true -> Header2 bor 64;
        false-> Header2
    end,
    Header22=case Request#dubbo_request.is_event of
                 true -> Header21 bor 32;
                 false-> Header21
             end,
    RequestId = Request#dubbo_request.mid,
    Header = << ?DUBBO_MEGIC:16,Header22:8,RequestState:8,RequestId:64,DataLen:32>>,
    Header.
encode_request_data(?SERIALIZATION_FASTJSON,Request)->
    dubbo_serializa_json:encode_request_data(Request);

encode_request_data(?SERIALIZATION_HESSIAN,Request)->
    dubbo_serializa_hessian:encode_request_data(Request).


-spec encode_response(#dubbo_response{})-> {ok,term()}.
encode_response(Response)->
    {ok,ResponseData} = encode_response_data(Response#dubbo_response.serialize_type,Response),
    Size = byte_size(ResponseData),
    Header = encode_response_header(Response,Size,?RESPONSE_STATE_OK),
    ResponseContent = <<Header/binary,ResponseData/binary>>,
    {ok, ResponseContent}.

encode_response_data(?SERIALIZATION_FASTJSON,Response)->
    {ok,Bin} = dubbo_serializa_json:encode_response_data(Response),
    {ok,Bin};
encode_response_data(?SERIALIZATION_HESSIAN,Response)->

    {ok,Bin} = dubbo_serializa_hessian:encode_response_data(Response),
    {ok,Bin}.

encode_response_header(Response,DataLen, ResponseState)->
    Header2= Response#dubbo_response.serialize_type,
    Header21=case Response#dubbo_response.is_twoway of
                 true -> Header2 bor 64;
                 false-> Header2
             end,
    Header22=case Response#dubbo_response.is_event of
                 true -> Header21 bor 32;
                 false-> Header21
             end,
    RequestId = Response#dubbo_response.mid,
    Header = << ?DUBBO_MEGIC:16,Header22:8, ResponseState:8,RequestId:64,DataLen:32>>,
    Header.


-spec(decode_header(Header::binary())-> {State::ok|error,Type::request|response,Data::dubbo_response()|dubbo_request()}).
decode_header(Header)->
    <<?DUBBO_MEGIC_HIGH,?DUBBO_MEGIC_LOW,Flag:8,State:8,Mid:64,DataLen:32>> = Header,
    if
        (Flag band 16#80) == 0 ->
            {DecodeState,Res} = decode_header(response,Flag,State,Mid,DataLen),
            {DecodeState,response,Res};
        true ->
            {DecodeState,Req} = decode_header(request,Flag,State,Mid,DataLen),
            {DecodeState,request,Req}
    end.
decode_header(request,Flag,_State,Mid,_DataLen)->
    SerializeType = Flag band 16#1f,
    IsTwoWay = if
                   (Flag band 16#40) /=0 -> true;
                   true -> false
    end,
    IsEvent = if
                  (Flag band 16#20) /=0 -> true;
                  true -> false
              end,
    Req = #dubbo_request{
        is_event = IsEvent,
        is_twoway = IsTwoWay,
        mid = Mid,
        mversion = <<"2.0.0">>,
        serialize_type = SerializeType
    },
    {ok,Req};
decode_header(response,Flag,State,Mid,_DataLen)->
    SerializeType = Flag band 16#1f,
    IsEvent = if
        (Flag band 16#20) /= 0 -> true;
        true -> false
    end,
    Res = #dubbo_response{is_event = IsEvent,
        serialize_type = SerializeType,
        state = State,
        mid = Mid
    },
    {ok,Res}.

-spec decode_response(#dubbo_response{},binary())-> {ok,#dubbo_response{}}.
decode_response(Res,Data)->
    case Res#dubbo_response.serialize_type of
        ?SERIALIZATION_FASTJSON ->
            dubbo_serializa_json:decode_response(Res,Data);
        ?SERIALIZATION_HESSIAN ->
            dubbo_serializa_hessian:decode_response(Res,Data)
    end.


-spec decode_request(#dubbo_request{},binary())-> {ok,#dubbo_request{}}.
decode_request(Req,Data)->
    case Req#dubbo_request.serialize_type of
        ?SERIALIZATION_FASTJSON ->
            dubbo_serializa_json:decode_request(Req,Data);
        ?SERIALIZATION_HESSIAN ->
            dubbo_serializa_hessian:decode_request(Req,Data)
    end.