substantial refactoring of api and decoder internals

This commit is contained in:
alisdair sullivan 2010-06-20 17:00:08 -07:00
parent c3bdc3b681
commit cff4d17561
9 changed files with 304 additions and 718 deletions

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%% The MIT License
%% Copyright (c) 2010 Alisdair Sullivan <alisdairsullivan@yahoo.ca>
%% 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.
%% this module is an example of how to use the raw parser api
-module(jsx_parser).
-author("alisdairsullivan@yahoo.ca").
-export([decode/1, event/2]).
%% export to allow the dirty hack below
-export([literal/1, string/1, float/1, integer/1]).
%% this is a strict parser, no comments, no naked values and only one key per object. it
%% also is not streaming, though it could be modified to parse partial objects/lists.
%% event takes two arguments, the result of calling the parser on a json argument (or the
%% generator returned by the parser) and a term that holds the erlang representation of
%% the json.
decode(JSON) ->
F = jsx:parser(),
try event(F(JSON), [])
catch error:badjson -> {error, badjson}
end.
%% erlang representation is dicts for objects and lists for arrays.
event({start_object, Next}, Stack) ->
event(Next(), [dict:new()] ++ Stack);
event({start_array, Next}, Stack) ->
event(Next(), [[]] ++ Stack);
event({end_object, Next}, [Object, {key, Key}, Parent|Stack]) when is_tuple(Parent) ->
event(Next(), [insert(Key, Object, Parent)] ++ Stack);
event({end_array, Next}, [Array, {key, Key}, Parent|Stack]) when is_tuple(Parent) ->
event(Next(), [insert(Key, lists:reverse(Array), Parent)] ++ Stack);
event({end_object, Next}, [Object, Parent|Stack]) when is_list(Parent) ->
event(Next(), [[Object] ++ Parent] ++ Stack);
event({end_array, Next}, [Array, Parent|Stack]) when is_list(Parent) ->
event(Next(), [[lists:reverse(Array)] ++ Parent] ++ Stack);
%% special cases for closing the root objects
event({end_object, Next}, [Object]) ->
event(Next(), [Object]);
event({end_array, Next}, [Array]) ->
event(Next(), [lists:reverse(Array)]);
%% keys are just pushed onto the stack until their corresponding value is
%% encountered
event({{key, Key}, Next}, [Stack]) ->
event(Next(), [{key, Key}] ++ Stack);
%% reject values that aren't wrapped by an array or object
event({{_Type, _Value}, _Next}, []) ->
{error, badjson};
%% this is kind of a dirty hack, but erlang will interpret atoms when applied to (Args)
%% as a function. so naming our formatting functions string, integer, float and literal will
%% allow the following shortcut
event({{Type, Value}, Next}, [{key, Key}, Object|Stack]) ->
event(Next(), [insert(Key, ?MODULE:Type(Value), Object)] ++ Stack);
event({{Type, Value}, Next}, [Array|Stack]) when is_list(Array) ->
event(Next(), [[?MODULE:Type(Value)] ++ Array] ++ Stack);
event({end_json, _}, [Stack]) ->
Stack.
%% we're restricting keys to one occurence per object, as the spec implies.
insert(Key, Val, Dict) ->
case dict:is_key(Key, Dict) of
false -> dict:store(Key, Val, Dict)
; true -> erlang:error(badjson)
end.
%% strings and literals we just return with no post-processing, numbers we convert
%% from strings to integers/floats as appropriate
string(String) ->
String.
integer(Number) ->
list_to_integer(Number).
float(Number) ->
list_to_float(Number).
literal(Literal) ->
Literal.

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%% The MIT License
%% Copyright (c) 2010 Alisdair Sullivan <alisdairsullivan@yahoo.ca>
%% 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_prettify).
-author("alisdairsullivan@yahoo.ca").
-export([pretty/2, prettify/2]).
-record(opts, {
indent = " "
}).
pretty(JSON, Opts) ->
Init = init(parse_opts(Opts, #opts{})),
P = jsx:parser({jsx_prettify, prettify, Init}, []),
case P(JSON) of
{incomplete, _} -> {error, badjson}
; {error, badjson} -> {error, badjson}
; {Result, _} -> Result
end.
parse_opts([{indent, Val}|Rest], Opts) ->
parse_opts(Rest, Opts#opts{indent = [ 16#20 || _ <- lists:seq(1, Val) ]});
parse_opts([], Opts) ->
Opts.
init(Opts) ->
{[], Opts#opts.indent, 0, new}.
prettify(start_object, {Acc, Indent, Level, value}) ->
{Acc ++ ",\n" ++ indent(Indent, Level) ++ "{", Indent, Level + 1, new};
prettify(start_object, {Acc, Indent, Level, new}) ->
{Acc ++ ",\n" ++ indent(Indent, Level) ++ "{", Indent, Level + 1, new};
prettify(start_object, {Acc, Indent, Level, _}) ->
{Acc ++ "{", Indent, Level + 1, new};
prettify(start_array, {Acc, Indent, Level, value}) ->
{Acc ++ ",\n" ++ indent(Indent, Level) ++ "[", Indent, Level + 1, new};
prettify(start_array, {Acc, Indent, Level, new}) ->
{Acc ++ ",\n" ++ indent(Indent, Level) ++ "[", Indent, Level + 1, new};
prettify(start_array, {Acc, Indent, Level, _}) ->
{Acc ++ "[", Indent, Level + 1, new};
prettify(end_object, {Acc, Indent, Level, value}) ->
{Acc ++ "\n" ++ indent(Indent, Level - 1) ++ "}", Indent, Level - 1, value};
prettify(end_object, {Acc, Indent, Level, new}) ->
{Acc ++ "}", Indent, Level - 1, value};
prettify(end_array, {Acc, Indent, Level, value}) ->
{Acc ++ "\n" ++ indent(Indent, Level - 1) ++ "]", Indent, Level - 1, value};
prettify(end_array, {Acc, Indent, Level, new}) ->
{Acc ++ "]", Indent, Level - 1, value};
prettify({key, Key}, {Acc, Indent, Level, value}) ->
{Acc ++ ",\n" ++ indent(Indent, Level) ++ "\"" ++ Key ++ "\": ", Indent, Level, key};
prettify({key, Key}, {Acc, Indent, Level, _}) ->
{Acc ++ "\n" ++ indent(Indent, Level) ++ "\"" ++ Key ++ "\": ", Indent, Level, key};
prettify({Type, Value}, {Acc, Indent, Level, value}) ->
{Acc ++ ",\n" ++ indent(Indent, Level) ++ format(Type, Value), Indent, Level, value};
prettify({Type, Value}, {Acc, Indent, Level, new}) ->
{Acc ++ "\n" ++ indent(Indent, Level) ++ format(Type, Value), Indent, Level, value};
prettify({Type, Value}, {Acc, Indent, Level, key}) ->
{Acc ++ format(Type, Value), Indent, Level, value};
prettify(reset, {_, Indent, _, _}) ->
{[], Indent, 0, new};
prettify(end_json, {Acc, _, _, _}) ->
Acc.
format(string, String) ->
"\"" ++ String ++ "\"";
format(literal, Literal) ->
erlang:atom_to_list(Literal);
format(_, Number) ->
Number.
indent(Indent, Level) ->
indent(Indent, Level, "").
indent(Indent, 0, Acc) ->
Acc;
indent(Indent, N, Acc) ->
Indent ++ Acc.

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%% The MIT License
%% Copyright (c) 2010 Alisdair Sullivan <alisdairsullivan@yahoo.ca>
%% 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_stream_parser).
-author("alisdairsullivan@yahoo.ca").
-export([decoder/1, event/2]).
decoder(Opts) ->
Decoder = jsx:parser({jsx_stream_parser, event, 0}, Opts),
fun(Stream) -> try
case Decoder(Stream) of
{incomplete, F} -> {incomplete, F}
; {error, badjson} -> {error, badjson}
end
catch
throw:{ok, Result} -> {ok, Result}
; throw:not_found -> {error, not_found}
end
end.
event(start_object, Level) ->
Level + 1;
event(start_array, 0) ->
throw(not_found);
event(start_array, Level) ->
Level + 1;
event(end_object, Level) ->
Level - 1;
event(end_array, Level) ->
Level - 1;
event({key, "_id"}, 1) ->
capture;
event({string, String}, capture) ->
throw({ok, String});
event(reset, _) ->
0;
event(end_json, _) ->
throw(not_found);
event(_, Level) ->
Level.

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%% The MIT License
%% Copyright (c) 2010 Alisdair Sullivan <alisdairsullivan@yahoo.ca>
%% 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_verify).
-author("alisdairsullivan@yahoo.ca").
-export([is_json/1, event/2]).
%% this is a strict parser, no comments, no naked values and only one key per object. it
%% also is not streaming, though it could be modified to parse partial objects/lists.
is_json(JSON) ->
P = jsx:parser({jsx_verify, event, ok}, []),
case P(JSON) of
{incomplete, _} ->
false
; {error, badjson} ->
false
; _ ->
true
end.
%% erlang representation is dicts for objects and lists for arrays. these are pushed
%% onto a stack, the top of which is our current level, deeper levels represent parent
%% and grandparent levels in the json structure. keys are also stored on top of the array
%% during parsing of their associated values.
event(_, ok) ->
ok.