%% Copyright (c) 2014, 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_http_te).
%% Identity.
-export([stream_identity/2]).
-export([identity/1]).
%% Chunked.
-export([stream_chunked/2]).
-export([chunk/1]).
-export([last_chunk/0]).
%% The state type is the same for both identity and chunked.
-type state() :: {non_neg_integer(), non_neg_integer()}.
-type decode_ret() :: more
| {more, Data::binary(), state()}
| {more, Data::binary(), RemLen::non_neg_integer(), state()}
| {more, Data::binary(), Rest::binary(), state()}
| {done, TotalLen::non_neg_integer(), Rest::binary()}
| {done, Data::binary(), TotalLen::non_neg_integer(), Rest::binary()}.
-export_type([decode_ret/0]).
-ifdef(EXTRA).
dripfeed(<< C, Rest/bits >>, Acc, State, F) ->
case F(<< Acc/binary, C >>, State) of
more ->
dripfeed(Rest, << Acc/binary, C >>, State, F);
{more, _, State2} ->
dripfeed(Rest, <<>>, State2, F);
{more, _, _, State2} ->
dripfeed(Rest, <<>>, State2, F);
{more, _, _, Acc2, State2} ->
dripfeed(Rest, Acc2, State2, F);
{done, _, <<>>} ->
ok;
{done, _, _, <<>>} ->
ok
end.
-endif.
%% Identity.
%% @doc Decode an identity stream.
-spec stream_identity(Data, State)
-> {more, Data, Len, State} | {done, Data, Len, Data}
when Data::binary(), State::state(), Len::non_neg_integer().
stream_identity(Data, {Streamed, Total}) ->
Streamed2 = Streamed + byte_size(Data),
if
Streamed2 < Total ->
{more, Data, Total - Streamed2, {Streamed2, Total}};
true ->
Size = Total - Streamed,
<< Data2:Size/binary, Rest/bits >> = Data,
{done, Data2, Total, Rest}
end.
-spec identity(Data) -> Data when Data::iodata().
identity(Data) ->
Data.
-ifdef(TEST).
stream_identity_test() ->
{done, <<>>, 0, <<>>}
= stream_identity(identity(<<>>), {0, 0}),
{done, <<"\r\n">>, 2, <<>>}
= stream_identity(identity(<<"\r\n">>), {0, 2}),
{done, << 0:80000 >>, 10000, <<>>}
= stream_identity(identity(<< 0:80000 >>), {0, 10000}),
ok.
stream_identity_parts_test() ->
{more, << 0:8000 >>, 1999, S1}
= stream_identity(<< 0:8000 >>, {0, 2999}),
{more, << 0:8000 >>, 999, S2}
= stream_identity(<< 0:8000 >>, S1),
{done, << 0:7992 >>, 2999, <<>>}
= stream_identity(<< 0:7992 >>, S2),
ok.
-endif.
-ifdef(PERF).
%% Using the same data as the chunked one for comparison.
horse_stream_identity() ->
horse:repeat(10000,
stream_identity(<<
"4\r\n"
"Wiki\r\n"
"5\r\n"
"pedia\r\n"
"e\r\n"
" in\r\n\r\nchunks.\r\n"
"0\r\n"
"\r\n">>, {0, 43})
).
horse_stream_identity_dripfeed() ->
horse:repeat(10000,
dripfeed(<<
"4\r\n"
"Wiki\r\n"
"5\r\n"
"pedia\r\n"
"e\r\n"
" in\r\n\r\nchunks.\r\n"
"0\r\n"
"\r\n">>, <<>>, {0, 43}, fun stream_identity/2)
).
-endif.
%% Chunked.
%% @doc Decode a chunked stream.
-spec stream_chunked(Data, State)
-> more | {more, Data, State} | {more, Data, Len, State}
| {more, Data, Data, State}
| {done, Len, Data} | {done, Data, Len, Data}
when Data::binary(), State::state(), Len::non_neg_integer().
stream_chunked(Data, State) ->
stream_chunked(Data, State, <<>>).
%% New chunk.
stream_chunked(Data = << C, _/bits >>, {0, Streamed}, Acc) when C =/= $\r ->
case chunked_len(Data, Streamed, Acc, 0) of
{next, Rest, State, Acc2} ->
stream_chunked(Rest, State, Acc2);
{more, State, Acc2} ->
{more, Acc2, Data, State};
Ret ->
Ret
end;
%% Trailing \r\n before next chunk.
stream_chunked(<< "\r\n", Rest/bits >>, {2, Streamed}, Acc) ->
stream_chunked(Rest, {0, Streamed}, Acc);
%% Trailing \r before next chunk.
stream_chunked(<< "\r" >>, {2, Streamed}, Acc) ->
{more, Acc, {1, Streamed}};
%% Trailing \n before next chunk.
stream_chunked(<< "\n", Rest/bits >>, {1, Streamed}, Acc) ->
stream_chunked(Rest, {0, Streamed}, Acc);
%% More data needed.
stream_chunked(<<>>, State = {Rem, _}, Acc) ->
{more, Acc, Rem, State};
%% Chunk data.
stream_chunked(Data, {Rem, Streamed}, Acc) when Rem > 2 ->
DataSize = byte_size(Data),
RemSize = Rem - 2,
case Data of
<< Chunk:RemSize/binary, "\r\n", Rest/bits >> ->
stream_chunked(Rest, {0, Streamed + RemSize}, << Acc/binary, Chunk/binary >>);
<< Chunk:RemSize/binary, "\r" >> ->
{more, << Acc/binary, Chunk/binary >>, {1, Streamed + RemSize}};
%% Everything in Data is part of the chunk.
_ ->
Rem2 = Rem - DataSize,
{more, << Acc/binary, Data/binary >>, Rem2, {Rem2, Streamed + DataSize}}
end.
chunked_len(<< $0, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16);
chunked_len(<< $1, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 1);
chunked_len(<< $2, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 2);
chunked_len(<< $3, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 3);
chunked_len(<< $4, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 4);
chunked_len(<< $5, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 5);
chunked_len(<< $6, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 6);
chunked_len(<< $7, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 7);
chunked_len(<< $8, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 8);
chunked_len(<< $9, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 9);
chunked_len(<< $A, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 10);
chunked_len(<< $B, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 11);
chunked_len(<< $C, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 12);
chunked_len(<< $D, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 13);
chunked_len(<< $E, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 14);
chunked_len(<< $F, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 15);
chunked_len(<< $a, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 10);
chunked_len(<< $b, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 11);
chunked_len(<< $c, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 12);
chunked_len(<< $d, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 13);
chunked_len(<< $e, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 14);
chunked_len(<< $f, R/bits >>, S, A, Len) -> chunked_len(R, S, A, Len * 16 + 15);
%% Final chunk.
chunked_len(<< "\r\n\r\n", R/bits >>, S, <<>>, 0) -> {done, S, R};
chunked_len(<< "\r\n\r\n", R/bits >>, S, A, 0) -> {done, A, S, R};
chunked_len(_, _, _, 0) -> more;
%% Normal chunk. Add 2 to Len for the trailing \r\n.
chunked_len(<< "\r\n", R/bits >>, S, A, Len) -> {next, R, {Len + 2, S}, A};
chunked_len(<<"\r">>, _, <<>>, _) -> more;
chunked_len(<<"\r">>, S, A, _) -> {more, {0, S}, A};
chunked_len(<<>>, _, <<>>, _) -> more;
chunked_len(<<>>, S, A, _) -> {more, {0, S}, A}.
%% @doc Encode a chunk.
-spec chunk(D) -> D when D::iodata().
chunk(Data) ->
[integer_to_list(iolist_size(Data), 16), <<"\r\n">>,
Data, <<"\r\n">>].
%% @doc Encode the last chunk of a chunked stream.
-spec last_chunk() -> << _:40 >>.
last_chunk() ->
<<"0\r\n\r\n">>.
-ifdef(TEST).
stream_chunked_identity_test() ->
{done, <<"Wikipedia in\r\n\r\nchunks.">>, 23, <<>>}
= stream_chunked(iolist_to_binary([
chunk("Wiki"),
chunk("pedia"),
chunk(" in\r\n\r\nchunks."),
last_chunk()
]), {0, 0}),
ok.
stream_chunked_one_pass_test() ->
{done, 0, <<>>} = stream_chunked(<<"0\r\n\r\n">>, {0, 0}),
{done, <<"Wikipedia in\r\n\r\nchunks.">>, 23, <<>>}
= stream_chunked(<<
"4\r\n"
"Wiki\r\n"
"5\r\n"
"pedia\r\n"
"e\r\n"
" in\r\n\r\nchunks.\r\n"
"0\r\n"
"\r\n">>, {0, 0}),
ok.
stream_chunked_n_passes_test() ->
S0 = {0, 0},
more = stream_chunked(<<"4\r">>, S0),
{more, <<>>, 6, S1} = stream_chunked(<<"4\r\n">>, S0),
{more, <<"Wiki">>, 0, S2} = stream_chunked(<<"Wiki\r\n">>, S1),
{more, <<"pedia">>, 0, <<"e\r">>, S3} = stream_chunked(<<"5\r\npedia\r\ne\r">>, S2),
{more, <<" in\r\n\r\nchunks.">>, 2, S4} = stream_chunked(<<"e\r\n in\r\n\r\nchunks.">>, S3),
{done, 23, <<>>} = stream_chunked(<<"\r\n0\r\n\r\n">>, S4),
%% A few extra for coverage purposes.
more = stream_chunked(<<"\n3">>, {1, 0}),
{more, <<"abc">>, 2, {2, 3}} = stream_chunked(<<"\n3\r\nabc">>, {1, 0}),
{more, <<"abc">>, {1, 3}} = stream_chunked(<<"3\r\nabc\r">>, {0, 0}),
{more, <<"abc">>, 0, <<"123">>, {0, 3}} = stream_chunked(<<"3\r\nabc\r\n123">>, {0, 0}),
ok.
stream_chunked_dripfeed_test() ->
dripfeed(<<
"4\r\n"
"Wiki\r\n"
"5\r\n"
"pedia\r\n"
"e\r\n"
" in\r\n\r\nchunks.\r\n"
"0\r\n"
"\r\n">>, <<>>, {0, 0}, fun stream_chunked/2).
stream_chunked_error_test_() ->
Tests = [
{<<>>, undefined},
{<<"\n\naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa">>, {2, 0}}
],
[{lists:flatten(io_lib:format("value ~p state ~p", [V, S])),
fun() -> {'EXIT', _} = (catch stream_chunked(V, S)) end}
|| {V, S} <- Tests].
-endif.
-ifdef(PERF).
horse_stream_chunked() ->
horse:repeat(10000,
stream_chunked(<<
"4\r\n"
"Wiki\r\n"
"5\r\n"
"pedia\r\n"
"e\r\n"
" in\r\n\r\nchunks.\r\n"
"0\r\n"
"\r\n">>, {0, 0})
).
horse_stream_chunked_dripfeed() ->
horse:repeat(10000,
dripfeed(<<
"4\r\n"
"Wiki\r\n"
"5\r\n"
"pedia\r\n"
"e\r\n"
" in\r\n\r\nchunks.\r\n"
"0\r\n"
"\r\n">>, <<>>, {0, 43}, fun stream_chunked/2)
).
-endif.
