diff options
| -rw-r--r-- | src/cowboy_multipart.erl | 92 |
1 files changed, 75 insertions, 17 deletions
diff --git a/src/cowboy_multipart.erl b/src/cowboy_multipart.erl index fc889ef..a9c378e 100644 --- a/src/cowboy_multipart.erl +++ b/src/cowboy_multipart.erl @@ -74,17 +74,51 @@ parse(Bin, Boundary) -> more(Bin, fun (NewBin) -> parse(NewBin, Boundary) end). -type pattern() :: {binary:cp(), non_neg_integer()}. +-type patterns() :: {pattern(), pattern()}. -%% @doc Return a compiled binary pattern with its size in bytes. -%% The pattern is the boundary prepended with "\r\n--". --spec pattern(binary()) -> pattern(). +%% @doc Return two compiled binary patterns with their sizes in bytes. +%% The boundary pattern is the boundary prepended with "\r\n--". +%% The boundary suffix pattern matches all prefixes of the boundary. +-spec pattern(binary()) -> patterns(). pattern(Boundary) -> MatchPattern = <<"\r\n--", Boundary/binary>>, - {binary:compile_pattern(MatchPattern), byte_size(MatchPattern)}. + MatchPrefixes = prefixes(MatchPattern), + {{binary:compile_pattern(MatchPattern), byte_size(MatchPattern)}, + {binary:compile_pattern(MatchPrefixes), byte_size(MatchPattern)}}. + +%% @doc Return all prefixes of a binary string. +%% The list of prefixes includes the full string. +-spec prefixes(binary()) -> [binary()]. +prefixes(<<C, Rest/binary>>) -> + prefixes(Rest, <<C>>). + +-spec prefixes(binary(), binary()) -> [binary()]. +prefixes(<<C, Rest/binary>>, Acc) -> + [Acc|prefixes(Rest, <<Acc/binary, C>>)]; +prefixes(<<>>, Acc) -> + [Acc]. + +%% @doc Test if a boundary is a possble suffix. +%% The patterns are expected to have been returned from `pattern/1`. +-spec suffix_match(binary(), patterns()) -> nomatch | {integer(), integer()}. +suffix_match(Bin, {_Boundary, {Pat, Len}}) -> + Size = byte_size(Bin), + suffix_match(Bin, Pat, Size, max(-Size, -Len)). + +-spec suffix_match(binary(), tuple(), non_neg_integer(), 0|neg_integer()) -> + nomatch | {integer(), integer()}. +suffix_match(_Bin, _Pat, _Size, _Match=0) -> + nomatch; +suffix_match(Bin, Pat, Size, Match) when Match < 0 -> + case binary:match(Bin, Pat, [{scope, {Size, Match}}]) of + {Pos, Len}=Part when Pos + Len =:= Size -> Part; + {_, Len} -> suffix_match(Bin, Pat, Size, Match + Len); + nomatch -> nomatch + end. %% @doc Parse remaining characters of a line beginning with the boundary. %% If followed by "--", <em>eof</em> is returned and parsing is finished. --spec parse_boundary_tail(binary(), pattern()) -> more(part_result()). +-spec parse_boundary_tail(binary(), patterns()) -> more(part_result()). parse_boundary_tail(Bin, Pattern) when byte_size(Bin) >= 2 -> case Bin of <<"--", _Rest/binary>> -> @@ -100,7 +134,7 @@ parse_boundary_tail(Bin, Pattern) -> more(Bin, fun (NewBin) -> parse_boundary_tail(NewBin, Pattern) end). %% @doc Skip whitespace and unknown chars until CRLF. --spec parse_boundary_eol(binary(), pattern()) -> more(part_result()). +-spec parse_boundary_eol(binary(), patterns()) -> more(part_result()). parse_boundary_eol(Bin, Pattern) -> case binary:match(Bin, <<"\r\n">>) of {CrlfStart, _Length} -> @@ -115,7 +149,7 @@ parse_boundary_eol(Bin, Pattern) -> more(Rest, fun (NewBin) -> parse_boundary_eol(NewBin, Pattern) end) end. --spec parse_boundary_crlf(binary(), pattern()) -> more(part_result()). +-spec parse_boundary_crlf(binary(), patterns()) -> more(part_result()). parse_boundary_crlf(<<"\r\n", Rest/binary>>, Pattern) -> % The binary is at least 2 bytes long as this function is only called by % parse_boundary_eol/3 when CRLF has been found so a more tuple will never @@ -127,11 +161,11 @@ parse_boundary_crlf(Bin, Pattern) -> % considered part of the boundary so EOL needs to be searched again. parse_boundary_eol(Bin, Pattern). --spec parse_headers(binary(), pattern()) -> more(part_result()). +-spec parse_headers(binary(), patterns()) -> more(part_result()). parse_headers(Bin, Pattern) -> parse_headers(Bin, Pattern, []). --spec parse_headers(binary(), pattern(), http_headers()) -> more(part_result()). +-spec parse_headers(binary(), patterns(), http_headers()) -> more(part_result()). parse_headers(Bin, Pattern, Acc) -> case erlang:decode_packet(httph_bin, Bin, []) of {ok, {http_header, _, Name, _, Value}, Rest} -> @@ -150,8 +184,8 @@ parse_headers(Bin, Pattern, Acc) -> more(Bin, fun (NewBin) -> parse_headers(NewBin, Pattern, Acc) end) end. --spec parse_body(binary(), pattern()) -> more(body_result()). -parse_body(Bin, Pattern = {P, PSize}) when byte_size(Bin) >= PSize -> +-spec parse_body(binary(), patterns()) -> more(body_result()). +parse_body(Bin, Pattern = {{P, PSize}, _}) when byte_size(Bin) >= PSize -> case binary:match(Bin, P) of {0, _Length} -> <<_:PSize/binary, Rest/binary>> = Bin, @@ -163,19 +197,27 @@ parse_body(Bin, Pattern = {P, PSize}) when byte_size(Bin) >= PSize -> FResult = end_of_part(Rest, Pattern), {body, PBody, fun () -> FResult end}; nomatch -> - PartialLength = byte_size(Bin) - PSize + 1, - <<PBody:PartialLength/binary, Rest/binary>> = Bin, - {body, PBody, fun () -> parse_body(Rest, Pattern) end} + case suffix_match(Bin, Pattern) of + nomatch -> + %% Prefix of boundary not found at end of input. it's + %% safe to return the whole binary. Saves copying of + %% next input onto tail of current input binary. + {body, Bin, fun () -> parse_body(<<>>, Pattern) end}; + {BoundaryStart, Len} -> + PBody = binary:part(Bin, BoundaryStart, Len), + Rest = binary:part(Bin, 0, BoundaryStart), + {body, PBody, fun () -> parse_body(Rest, Pattern) end} + end end; parse_body(Bin, Pattern) -> more(Bin, fun (NewBin) -> parse_body(NewBin, Pattern) end). --spec end_of_part(binary(), pattern()) -> end_of_part(). +-spec end_of_part(binary(), patterns()) -> end_of_part(). end_of_part(Bin, Pattern) -> {end_of_part, fun () -> parse_boundary_tail(Bin, Pattern) end}. --spec skip(binary(), pattern()) -> more(part_result()). -skip(Bin, Pattern = {P, PSize}) -> +-spec skip(binary(), patterns()) -> more(part_result()). +skip(Bin, Pattern = {{P, PSize}, _}) -> case binary:match(Bin, P) of {BoundaryStart, _Length} -> % Boundary found, proceed with parsing of the next part. @@ -255,4 +297,20 @@ title(Bin) -> ), iolist_to_binary(Title). +suffix_test_() -> + [?_assertEqual(Part, suffix_match(Packet, pattern(Boundary))) || + {Part, Packet, Boundary} <- [ + {nomatch, <<>>, <<"ABC">>}, + {{0, 1}, <<"\r">>, <<"ABC">>}, + {{0, 2}, <<"\r\n">>, <<"ABC">>}, + {{0, 4}, <<"\r\n--">>, <<"ABC">>}, + {{0, 5}, <<"\r\n--A">>, <<"ABC">>}, + {{0, 6}, <<"\r\n--AB">>, <<"ABC">>}, + {{0, 7}, <<"\r\n--ABC">>, <<"ABC">>}, + {nomatch, <<"\r\n--AB1">>, <<"ABC">>}, + {{1, 1}, <<"1\r">>, <<"ABC">>}, + {{2, 2}, <<"12\r\n">>, <<"ABC">>}, + {{3, 4}, <<"123\r\n--">>, <<"ABC">>} + ]]. + -endif. |