cow cache is not same, as map read will modify the underlying map. use sync.Map for 1.9 and above, and mutex if sync.Map not available

feature_config_with_sync_map.go

@@ -0,0 +1,51 @@
+//+build go1.9
+
+package jsoniter
+
+import (
+	"reflect"
+	"sync"
+)
+
+type frozenConfig struct {
+	configBeforeFrozen            Config
+	sortMapKeys                   bool
+	indentionStep                 int
+	objectFieldMustBeSimpleString bool
+	onlyTaggedField               bool
+	decoderCache                  sync.Map
+	encoderCache                  sync.Map
+	extensions                    []Extension
+	streamPool                    chan *Stream
+	iteratorPool                  chan *Iterator
+}
+
+func (cfg *frozenConfig) initCache() {
+	cfg.decoderCache = sync.Map{}
+	cfg.encoderCache = sync.Map{}
+}
+
+
+func (cfg *frozenConfig) addDecoderToCache(cacheKey reflect.Type, decoder ValDecoder) {
+	cfg.decoderCache.Store(cacheKey, decoder)
+}
+
+func (cfg *frozenConfig) addEncoderToCache(cacheKey reflect.Type, encoder ValEncoder) {
+	cfg.encoderCache.Store(cacheKey, encoder)
+}
+
+func (cfg *frozenConfig) getDecoderFromCache(cacheKey reflect.Type) ValDecoder {
+	decoder, found := cfg.decoderCache.Load(cacheKey)
+	if found {
+		return decoder.(ValDecoder)
+	}
+	return nil
+}
+
+func (cfg *frozenConfig) getEncoderFromCache(cacheKey reflect.Type) ValEncoder {
+	encoder, found := cfg.encoderCache.Load(cacheKey)
+	if found {
+		return encoder.(ValEncoder)
+	}
+	return nil
+}