Question

dec_lines(Msg, Lines) ->
    dec_lines(Msg, Lines, fun hdr/5).
dec_lines(Msg, Lines, DecodeFun) ->
    lists:foldl(fun(L1, M) -> dec_line(M, L1, DecodeFun) end, Msg, Lines).


dec_line(Msg, {Key, Line}, DecodeFun) ->
    KeyN = keyN(Key),
    case catch DecodeFun(decode, Key, undefined, Line, Msg) of
    {Msg1=#sip_msg{}, Bin1}  ->
        case skip_LWS(Bin1) of
        << ?CRLFb >> ->
            Msg1; 
        _Bin2 ->
            Msg#sip_msg{error_hdrs = [{Key, 
                           {KeyN, rem_trail_crlf_str(Line)}}
                          | Msg#sip_msg.error_hdrs]}
        end;
    _E -> 
        Msg#sip_msg{error_hdrs = [{Key, {KeyN, rem_trail_crlf_str(Line)}}
                      | Msg#sip_msg.error_hdrs]}
    end.

有趣的hdr / 5：

hdr(Op, Short=[_], O0, O1, O2) -> 
    case lists:member(Short, ?LONG) of
        true  -> hdr(Op, long(Short), O0, O1, O2);
        false -> case {Op, is_binary(O1)} of
                     {decode, true} -> hdr_dec(Short, O0, O1, O2);
                     _              -> hdr1(Op, Short, O1, O2)
                 end
    end;

这是一些dbg日志：

(<0.4158.10>) call sip_decode:keyN("history-info")
(<0.4158.10>) returned from sip_decode:keyN/1 -> 1
(<0.4158.10>) call sip_decode:skip_LWS(<<"\r\n">>)
(<0.4158.10>) returned from sip_decode:skip_LWS/1 -> <<"\r\n">>

我使用这些cmds：

dbg:stop_clear().
dbg:tracer().
dbg:p(all,c).
dbg:tpl(sip_decode,'_',[{'_',[],[{return_trace}]}]).

从dbg日志中，我们知道sip_decode:keyN和skip_LWS(Bin1)都是exectue，所以我认为catch DecodeFun(decode, Key, undefined, Line, Msg)应该被提取，结果匹配{Msg1=#sip_msg{}, Bin1}。

但是从dbg日志中，我找不到DecodeFun的来电，即hdr/5。

为什么dbg没有捕获某些函数调用？

0 个答案: