%% The MIT License %% Copyright (c) 2010 Alisdair Sullivan %% Permission is hereby granted, free of charge, to any person obtaining a copy %% of this software and associated documentation files (the "Software"), to deal %% in the Software without restriction, including without limitation the rights %% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell %% copies of the Software, and to permit persons to whom the Software is %% furnished to do so, subject to the following conditions: %% The above copyright notice and this permission notice shall be included in %% all copies or substantial portions of the Software. %% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR %% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, %% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE %% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER %% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, %% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN %% THE SOFTWARE. -module(jsx). -author("alisdairsullivan@yahoo.ca"). %% the core parser api -export([parser/0, parser/1]). %% example usage of core api -export([is_json/1, is_json/2]). -export([decode/1, decode/2, decode/3, decode/4]). -export([fold/1, fold/2, fold/3, fold/4]). %% types for function specifications -include("jsx_types.hrl"). -spec parser() -> jsx_parser(). -spec parser(Opts::jsx_opts()) -> jsx_parser(). parser() -> parser([]). parser(OptsList) -> F = case proplists:get_value(encoding, OptsList, auto) of utf8 -> fun jsx_utf8:parse/2 ; utf16 -> fun jsx_utf16:parse/2 ; utf32 -> fun jsx_utf32:parse/2 ; {utf16, little} -> fun jsx_utf16le:parse/2 ; {utf32, little} -> fun jsx_utf32le:parse/2 ; auto -> fun detect_encoding/2 end, start(F, OptsList). start(F, OptsList) -> Opts = parse_opts(OptsList), fun(Stream) -> F(Stream, Opts) end. -spec is_json(JSON::json()) -> true | false. -spec is_json(JSON::json(), Opts::jsx_opts()) -> true | false. is_json(JSON) -> is_json(JSON, []). is_json(JSON, Opts) -> case fold(fun(end_json, ok) -> true ;(_, _) -> ok end, ok, JSON, Opts) of {incomplete, _} -> false ; {error, _} -> false ; {ok, true} -> true end. -spec decode(JSON::json()) -> {ok, [jsx_event(),...]} | {error, atom()}. -spec decode(JSON::json(), Parse::jsx_opts() | jsx_parser()) -> {ok, [jsx_event(),...]} | {error, atom()}. -spec decode(F::fun((jsx_event(), any()) -> any()), Acc::any(), JSON::json()) -> {ok, any()} | {error, atom()}. -spec decode(F::fun((jsx_event(), any()) -> any()), Acc::any(), JSON::json(), Parse::jsx_opts() | jsx_parser()) -> {ok, any()} | {error, atom()}. decode(JSON) -> decode(JSON, []). decode(JSON, Parse) -> F = fun(end_json, S) -> lists:reverse(S) ;(E, S) -> [E] ++ S end, decode(F, [], JSON, Parse). decode(F, Acc, JSON) -> decode(F, Acc, JSON, []). decode(F, Acc, JSON, Parse) -> case fold(F, Acc, JSON, Parse) of {ok, Result} -> {ok, Result} ; _ -> {error, badjson} end. -spec fold(JSON::json()) -> {ok, [jsx_event(),...]} | {incomplete, jsx_parser(), fun(() -> jsx_parser_result())} | {error, atom()}. -spec fold(JSON::json(), Parse::jsx_opts() | jsx_parser()) -> {ok, [jsx_event(),...]} | {incomplete, jsx_parser(), fun(() -> jsx_parser_result())} | {error, atom()}. -spec fold(F::fun((jsx_event(), any()) -> any()), Acc::any(), JSON::json()) -> {ok, any()} | {incomplete, jsx_parser(), fun(() -> jsx_parser_result())} | {error, atom()}. -spec fold(F::fun((jsx_event(), any()) -> any()), Acc::any(), JSON::json(), Opts::jsx_opts()) -> {ok, any()} | {incomplete, jsx_parser(), fun(() -> jsx_parser_result())} | {error, atom()} ; (F::fun((jsx_event(), any()) -> any()), Acc::any(), JSON::json(), Parser::jsx_parser()) -> {ok, any()} | {incomplete, jsx_parser(), fun(() -> jsx_parser_result())} | {error, atom()}. fold(JSON) -> fold(JSON, []). fold(JSON, Parse) -> F = fun(end_json, S) -> lists:reverse(S) ;(E, S) -> [E] ++ S end, fold(F, [], JSON, Parse). fold(F, Acc, JSON) -> P = jsx:parser(), fold(F, Acc, JSON, P). fold(F, Acc, JSON, Opts) when is_list(Opts) -> P = jsx:parser(Opts), fold(F, Acc, JSON, P); fold(F, Acc, JSON, P) -> fold_loop(F, Acc, P(JSON)). fold_loop(F, Acc, {incomplete, Next, Force}) -> case Force() of {event, Val, End} -> case End() of {event, end_json, _} -> {ok, F(end_json, F(Val, Acc))} ; _ -> {incomplete, fun(Bin) -> fold_loop(F, Acc, Next(Bin)) end} end ; _ -> {incomplete, fun(Bin) -> fold_loop(F, Acc, Next(Bin)) end} end; fold_loop(_, _, {error, Error}) -> {error, Error}; fold_loop(F, Acc, {event, end_json, _}) -> {ok, F(end_json, Acc)}; fold_loop(F, Acc, {event, Event, Next}) -> fold_loop(F, F(Event, Acc), Next()). %% option parsing %% converts a proplist into a tuple parse_opts(Opts) -> parse_opts(Opts, {false, codepoint, false}). parse_opts([], Opts) -> Opts; parse_opts([{comments, Value}|Rest], {_Comments, EscapedUnicode, Stream}) -> true = lists:member(Value, [true, false]), parse_opts(Rest, {Value, EscapedUnicode, Stream}); parse_opts([{escaped_unicode, Value}|Rest], {Comments, _EscapedUnicode, Stream}) -> true = lists:member(Value, [ascii, codepoint, none]), parse_opts(Rest, {Comments, Value, Stream}); parse_opts([{stream_mode, Value}|Rest], {Comments, EscapedUnicode, _Stream}) -> true = lists:member(Value, [true, false]), parse_opts(Rest, {Comments, EscapedUnicode, Value}); parse_opts([{encoding, _}|Rest], Opts) -> parse_opts(Rest, Opts). %% encoding detection %% first check to see if there's a bom, if not, use the rfc4627 method for determining %% encoding. this function makes some assumptions about the validity of the stream %% which may delay failure later than if an encoding is explicitly provided %% utf8 bom detection detect_encoding(<<16#ef, 16#bb, 16#bf, Rest/binary>>, Opts) -> jsx_utf8:parse(Rest, Opts); %% utf32-little bom detection (this has to come before utf16-little) detect_encoding(<<16#ff, 16#fe, 0, 0, Rest/binary>>, Opts) -> jsx_utf32le:parse(Rest, Opts); %% utf16-big bom detection detect_encoding(<<16#fe, 16#ff, Rest/binary>>, Opts) -> jsx_utf16:parse(Rest, Opts); %% utf16-little bom detection detect_encoding(<<16#ff, 16#fe, Rest/binary>>, Opts) -> jsx_utf16le:parse(Rest, Opts); %% utf32-big bom detection detect_encoding(<<0, 0, 16#fe, 16#ff, Rest/binary>>, Opts) -> jsx_utf32:parse(Rest, Opts); %% utf32-little null order detection detect_encoding(<> = JSON, Opts) when X =/= 0 -> jsx_utf32le:parse(JSON, Opts); %% utf16-big null order detection detect_encoding(<<0, X, 0, Y, _Rest/binary>> = JSON, Opts) when X =/= 0, Y =/= 0 -> jsx_utf16:parse(JSON, Opts); %% utf16-little null order detection detect_encoding(<> = JSON, Opts) when X =/= 0, Y =/= 0 -> jsx_utf16le:parse(JSON, Opts); %% utf32-big null order detection detect_encoding(<<0, 0, 0, X, _Rest/binary>> = JSON, Opts) when X =/= 0 -> jsx_utf32:parse(JSON, Opts); %% utf8 null order detection detect_encoding(<> = JSON, Opts) when X =/= 0, Y =/= 0 -> jsx_utf8:parse(JSON, Opts); %% a problem, to autodetect naked single digits' encoding, there is not enough data %% to conclusively determine the encoding correctly. below is an attempt to solve %% the problem detect_encoding(<>, Opts) when X =/= 0 -> {incomplete, fun(Stream) -> detect_encoding(<>, Opts) end, fun() -> try {incomplete, _, Force} = jsx_utf8:parse(<>, Opts), Force() catch error:function_clause -> {error, badjson} end end }; detect_encoding(<<0, X>>, Opts) when X =/= 0 -> {incomplete, fun(Stream) -> detect_encoding(<<0, X, Stream/binary>>, Opts) end, fun() -> try {incomplete, _, Force} = jsx_utf16:parse(<<0, X>>, Opts), Force() catch error:function_clause -> {error, badjson} end end }; detect_encoding(<>, Opts) when X =/= 0 -> {incomplete, fun(Stream) -> detect_encoding(<>, Opts) end, fun() -> try {incomplete, _, Force} = jsx_utf16le:parse(<>, Opts), Force() catch error:function_clause -> {error, badjson} end end }; %% not enough input, request more detect_encoding(Bin, Opts) -> {incomplete, fun(Stream) -> detect_encoding(<>, Opts) end, fun() -> {error, badjson} end }.