introduce option to skip checking for repeated keys

jsxbench

@@ -39,8 +39,10 @@ main([]) ->
     format(frequency:profile({"empty array to json", ?averageN({jsx, encode, [[]]}, 1000)})),
     format(frequency:profile({"sample tweet to term", ?averageN({jsx, decode, [sample_tweet()]}, 1000)})),
     format(frequency:profile({"sample tweet to json", ?averageN({jsx, encode, [jsx:decode(sample_tweet())]}, 1000)})),
+    format(frequency:profile({"sample tweet to json (without key checks)", ?averageN({jsx, encode, [jsx:decode(sample_tweet()), [repeat_keys]]}, 1000)})),
     format(frequency:profile({"sample github user to term", ?averageN({jsx, decode, [sample_github_user()]}, 1000)})),
-    format(frequency:profile({"sample github user to json", ?averageN({jsx, encode, [jsx:decode(sample_github_user())]}, 1000)})).
+    format(frequency:profile({"sample github user to json", ?averageN({jsx, encode, [jsx:decode(sample_github_user())]}, 1000)})),
+    format(frequency:profile({"sample github user to json", ?averageN({jsx, encode, [jsx:decode(sample_github_user()), [repeat_keys]]}, 1000)})).
 
 
 format([]) -> ok;

src/jsx_config.erl

@@ -63,6 +63,8 @@ parse_config([unescaped_jsonp|Rest], Config) ->
     parse_config(Rest, Config#config{unescaped_jsonp=true});
 parse_config([dirty_strings|Rest], Config) ->
     parse_config(Rest, Config#config{dirty_strings=true});
+parse_config([repeat_keys|Rest], Config) ->
+    parse_config(Rest, Config#config{repeat_keys=true});
 parse_config([strict|Rest], Config) ->
     parse_config(Rest, Config#config{strict_comments=true,
         strict_commas=true,
@@ -146,6 +148,7 @@ valid_flags() ->
         escaped_strings,
         unescaped_jsonp,
         dirty_strings,
+        repeat_keys,
         strict,
         stream,
         error_handler,
@@ -184,6 +187,7 @@ config_test_() ->
                     escaped_strings = true,
                     unescaped_jsonp = true,
                     dirty_strings = true,
+                    repeat_keys = true,
                     strict_comments = true,
                     strict_commas = true,
                     strict_utf8 = true,
@@ -195,6 +199,7 @@ config_test_() ->
                     escaped_strings,
                     unescaped_jsonp,
                     dirty_strings,
+                    repeat_keys,
                     strict,
                     stream
                 ])
@@ -264,6 +269,7 @@ config_to_list_test_() ->
                 escaped_strings,
                 unescaped_jsonp,
                 dirty_strings,
+                repeat_keys,
                 stream,
                 strict
             ],
@@ -272,6 +278,7 @@ config_to_list_test_() ->
                     escaped_strings = true,
                     unescaped_jsonp = true,
                     dirty_strings = true,
+                    repeat_keys = true,
                     strict_comments = true,
                     strict_utf8 = true,
                     strict_single_quotes = true,

src/jsx_config.hrl

@@ -3,6 +3,7 @@
     escaped_strings = false             :: boolean(),
     unescaped_jsonp = false             :: boolean(),
     dirty_strings = false               :: boolean(),
+    repeat_keys = false                 :: boolean(),
     strict_comments = false             :: boolean(),
     strict_commas = false               :: boolean(),
     strict_utf8 = false                 :: boolean(),

src/jsx_parser.erl

@@ -141,6 +141,19 @@ object([end_object|Tokens], Handler, [{object, _}|Stack], Config) ->
 object([{key, Key}|Tokens], Handler, Stack, Config)
 when is_atom(Key); is_binary(Key); is_integer(Key) ->
     object([Key|Tokens], Handler, Stack, Config);
+object([Key|Tokens], Handler, [{object, _Keys}|Stack], Config=#config{repeat_keys=true})
+when is_atom(Key); is_binary(Key); is_integer(Key) ->
+    try clean_string(fix_key(Key), Config)
+    of K ->
+        value(
+            Tokens,
+            handle_event({key, K}, Handler, Config),
+            [{object, []}|Stack],
+            Config
+        )
+    catch error:badarg ->
+        ?error(object, [{string, Key}|Tokens], Handler, Stack, Config)
+    end;
 object([Key|Tokens], Handler, [{object, Keys}|Stack], Config)
 when is_atom(Key); is_binary(Key); is_integer(Key) ->
     try