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%% Copyright (c) Loïc Hoguin <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-module(cow_capsule).
%% Parsing.
-export([parse/1]).
%% Building.
-export([wt_drain_session/0]).
-export([wt_close_session/2]).
-type capsule() ::
wt_drain_session |
{wt_close_session, cow_http3:wt_app_error_code(), binary()}.
%% Parsing.
-spec parse(binary())
-> {ok, capsule(), binary()}
| {ok, binary()} %% Unknown capsule gets skipped.
| more
| {skip, non_neg_integer()} %% Unknown capsule; remaining length to skip.
| error.
%% @todo Handle DATAGRAM capsules. {datagram, binary()}
parse(<<2:2, 16#78ae:30, 0, Rest/bits>>) ->
{ok, wt_drain_session, Rest};
parse(<<1:2, 16#2843:14, Rest0/bits>>) when byte_size(Rest0) >= 5 ->
LenOrError = case Rest0 of
<<0:2, Len0:6, Rest1/bits>> ->
{Len0, Rest1};
<<1:2, Len0:14, Rest1/bits>> when Len0 =< 1028 ->
{Len0, Rest1};
%% AppCode is 4 bytes and AppMsg is up to 1024 bytes.
_ ->
error
end,
case LenOrError of
{Len1, Rest2} ->
AppMsgLen = Len1 - 4,
case Rest2 of
<<AppCode:32, AppMsg:AppMsgLen/binary, Rest/bits>> ->
{ok, {wt_close_session, AppCode, AppMsg}, Rest};
_ ->
more
end;
error ->
error
end;
parse(<<>>) ->
more;
%% Skip unknown capsules.
parse(Data) ->
%% @todo This can use maybe_expr in OTP-25+.
case cow_http3:parse_int(Data) of
more ->
more;
{_Type, Rest0} ->
case cow_http3:parse_int(Rest0) of
more ->
more;
{Len, Rest1} ->
case Rest1 of
<<_:Len/unit:8, Rest>> ->
{ok, Rest};
_ ->
{skip, Len - byte_size(Rest1)}
end
end
end.
%% Building.
-spec wt_drain_session() -> binary().
%% @todo Where should I put capsules?
wt_drain_session() ->
<<2:2, 16#78ae:30, 0>>.
-spec wt_close_session(cow_http3:wt_app_error_code(), iodata()) -> iodata().
wt_close_session(AppCode, <<>>) ->
<<1:2, 16#2843:14, 4, AppCode:32>>;
wt_close_session(AppCode, AppMsg) ->
Len = 4 + iolist_size(AppMsg),
[<<1:2, 16#2843:14>>, cow_http3:encode_int(Len), <<AppCode:32>>, AppMsg].
|
