mirror of
https://github.com/json-iterator/go.git
synced 2024-11-27 08:30:57 +02:00
460 lines
13 KiB
Go
460 lines
13 KiB
Go
package jsoniter
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import (
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"encoding"
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"encoding/json"
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"fmt"
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"reflect"
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"time"
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"unsafe"
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)
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// ValDecoder is an internal type registered to cache as needed.
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// Don't confuse jsoniter.ValDecoder with json.Decoder.
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// For json.Decoder's adapter, refer to jsoniter.AdapterDecoder(todo link).
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//
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// Reflection on type to create decoders, which is then cached
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// Reflection on value is avoided as we can, as the reflect.Value itself will allocate, with following exceptions
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// 1. create instance of new value, for example *int will need a int to be allocated
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// 2. append to slice, if the existing cap is not enough, allocate will be done using Reflect.New
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// 3. assignment to map, both key and value will be reflect.Value
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// For a simple struct binding, it will be reflect.Value free and allocation free
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type ValDecoder interface {
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Decode(ptr unsafe.Pointer, iter *Iterator)
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}
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// ValEncoder is an internal type registered to cache as needed.
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// Don't confuse jsoniter.ValEncoder with json.Encoder.
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// For json.Encoder's adapter, refer to jsoniter.AdapterEncoder(todo godoc link).
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type ValEncoder interface {
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IsEmpty(ptr unsafe.Pointer) bool
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Encode(ptr unsafe.Pointer, stream *Stream)
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EncodeInterface(val interface{}, stream *Stream)
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}
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func writeToStream(val interface{}, stream *Stream, encoder ValEncoder) {
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e := (*emptyInterface)(unsafe.Pointer(&val))
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if e.word == nil {
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stream.WriteNil()
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return
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}
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if reflect.TypeOf(val).Kind() == reflect.Ptr {
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encoder.Encode(unsafe.Pointer(&e.word), stream)
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} else {
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encoder.Encode(e.word, stream)
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}
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}
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type DecoderFunc func(ptr unsafe.Pointer, iter *Iterator)
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type EncoderFunc func(ptr unsafe.Pointer, stream *Stream)
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var jsonNumberType reflect.Type
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var jsonRawMessageType reflect.Type
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var jsoniterRawMessageType reflect.Type
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var anyType reflect.Type
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var marshalerType reflect.Type
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var unmarshalerType reflect.Type
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var textUnmarshalerType reflect.Type
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func init() {
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jsonNumberType = reflect.TypeOf((*json.Number)(nil)).Elem()
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jsonRawMessageType = reflect.TypeOf((*json.RawMessage)(nil)).Elem()
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jsoniterRawMessageType = reflect.TypeOf((*RawMessage)(nil)).Elem()
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anyType = reflect.TypeOf((*Any)(nil)).Elem()
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marshalerType = reflect.TypeOf((*json.Marshaler)(nil)).Elem()
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unmarshalerType = reflect.TypeOf((*json.Unmarshaler)(nil)).Elem()
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textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
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}
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type optionalDecoder struct {
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valueType reflect.Type
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valueDecoder ValDecoder
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}
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func (decoder *optionalDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
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if iter.ReadNil() {
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*((*unsafe.Pointer)(ptr)) = nil
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} else {
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if *((*unsafe.Pointer)(ptr)) == nil {
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// pointer to null, we have to allocate memory to hold the value
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value := reflect.New(decoder.valueType)
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decoder.valueDecoder.Decode(unsafe.Pointer(value.Pointer()), iter)
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*((*uintptr)(ptr)) = value.Pointer()
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} else {
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// reuse existing instance
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decoder.valueDecoder.Decode(*((*unsafe.Pointer)(ptr)), iter)
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}
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}
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}
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type optionalEncoder struct {
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valueEncoder ValEncoder
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}
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func (encoder *optionalEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
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if *((*unsafe.Pointer)(ptr)) == nil {
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stream.WriteNil()
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} else {
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encoder.valueEncoder.Encode(*((*unsafe.Pointer)(ptr)), stream)
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}
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}
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func (encoder *optionalEncoder) EncodeInterface(val interface{}, stream *Stream) {
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writeToStream(val, stream, encoder)
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}
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func (encoder *optionalEncoder) IsEmpty(ptr unsafe.Pointer) bool {
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if *((*unsafe.Pointer)(ptr)) == nil {
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return true
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} else {
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return encoder.valueEncoder.IsEmpty(*((*unsafe.Pointer)(ptr)))
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}
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}
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type placeholderEncoder struct {
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cfg *frozenConfig
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cacheKey reflect.Type
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}
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func (encoder *placeholderEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
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encoder.getRealEncoder().Encode(ptr, stream)
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}
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func (encoder *placeholderEncoder) EncodeInterface(val interface{}, stream *Stream) {
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writeToStream(val, stream, encoder)
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}
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func (encoder *placeholderEncoder) IsEmpty(ptr unsafe.Pointer) bool {
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return encoder.getRealEncoder().IsEmpty(ptr)
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}
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func (encoder *placeholderEncoder) getRealEncoder() ValEncoder {
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for i := 0; i < 30; i++ {
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realDecoder := encoder.cfg.getEncoderFromCache(encoder.cacheKey)
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_, isPlaceholder := realDecoder.(*placeholderEncoder)
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if isPlaceholder {
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time.Sleep(time.Second)
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} else {
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return realDecoder
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}
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}
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panic(fmt.Sprintf("real encoder not found for cache key: %v", encoder.cacheKey))
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}
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type placeholderDecoder struct {
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cfg *frozenConfig
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cacheKey reflect.Type
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}
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func (decoder *placeholderDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
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for i := 0; i < 30; i++ {
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realDecoder := decoder.cfg.getDecoderFromCache(decoder.cacheKey)
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_, isPlaceholder := realDecoder.(*placeholderDecoder)
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if isPlaceholder {
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time.Sleep(time.Second)
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} else {
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realDecoder.Decode(ptr, iter)
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return
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}
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}
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panic(fmt.Sprintf("real decoder not found for cache key: %v", decoder.cacheKey))
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}
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// emptyInterface is the header for an interface{} value.
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type emptyInterface struct {
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typ unsafe.Pointer
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word unsafe.Pointer
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}
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// emptyInterface is the header for an interface with method (not interface{})
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type nonEmptyInterface struct {
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// see ../runtime/iface.go:/Itab
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itab *struct {
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ityp unsafe.Pointer // static interface type
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typ unsafe.Pointer // dynamic concrete type
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link unsafe.Pointer
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bad int32
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unused int32
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fun [100000]unsafe.Pointer // method table
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}
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word unsafe.Pointer
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}
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// Read converts an Iterator instance into go interface, same as json.Unmarshal
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func (iter *Iterator) ReadVal(obj interface{}) {
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typ := reflect.TypeOf(obj)
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cacheKey := typ.Elem()
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decoder, err := decoderOfType(iter.cfg, cacheKey)
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if err != nil {
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iter.Error = err
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return
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}
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e := (*emptyInterface)(unsafe.Pointer(&obj))
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decoder.Decode(e.word, iter)
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}
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func (stream *Stream) WriteVal(val interface{}) {
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if nil == val {
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stream.WriteNil()
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return
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}
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typ := reflect.TypeOf(val)
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cacheKey := typ
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encoder, err := encoderOfType(stream.cfg, cacheKey)
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if err != nil {
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stream.Error = err
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return
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}
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encoder.EncodeInterface(val, stream)
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}
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type prefix string
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func (p prefix) addToDecoder(decoder ValDecoder, err error) (ValDecoder, error) {
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if err != nil {
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return nil, fmt.Errorf("%s: %s", p, err.Error())
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}
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return decoder, err
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}
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func (p prefix) addToEncoder(encoder ValEncoder, err error) (ValEncoder, error) {
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if err != nil {
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return nil, fmt.Errorf("%s: %s", p, err.Error())
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}
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return encoder, err
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}
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func decoderOfType(cfg *frozenConfig, typ reflect.Type) (ValDecoder, error) {
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cacheKey := typ
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decoder := cfg.getDecoderFromCache(cacheKey)
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if decoder != nil {
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return decoder, nil
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}
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decoder = getTypeDecoderFromExtension(typ)
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if decoder != nil {
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cfg.addDecoderToCache(cacheKey, decoder)
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return decoder, nil
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}
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decoder = &placeholderDecoder{cfg: cfg, cacheKey: cacheKey}
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cfg.addDecoderToCache(cacheKey, decoder)
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decoder, err := createDecoderOfType(cfg, typ)
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cfg.addDecoderToCache(cacheKey, decoder)
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return decoder, err
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}
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func createDecoderOfType(cfg *frozenConfig, typ reflect.Type) (ValDecoder, error) {
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if typ.String() == "[]uint8" {
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return &base64Codec{}, nil
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}
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if typ.AssignableTo(jsonRawMessageType) {
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return &jsonRawMessageCodec{}, nil
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}
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if typ.AssignableTo(jsoniterRawMessageType) {
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return &jsoniterRawMessageCodec{}, nil
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}
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if typ.AssignableTo(jsonNumberType) {
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return &jsonNumberCodec{}, nil
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}
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if typ.ConvertibleTo(unmarshalerType) {
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templateInterface := reflect.New(typ).Elem().Interface()
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var decoder ValDecoder = &unmarshalerDecoder{extractInterface(templateInterface)}
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if typ.Kind() != reflect.Struct {
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decoder = &optionalDecoder{typ, decoder}
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}
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return decoder, nil
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}
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if typ.ConvertibleTo(anyType) {
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return &anyCodec{}, nil
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}
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switch typ.Kind() {
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case reflect.String:
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return &stringCodec{}, nil
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case reflect.Int:
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return &intCodec{}, nil
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case reflect.Int8:
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return &int8Codec{}, nil
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case reflect.Int16:
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return &int16Codec{}, nil
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case reflect.Int32:
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return &int32Codec{}, nil
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case reflect.Int64:
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return &int64Codec{}, nil
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case reflect.Uint:
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return &uintCodec{}, nil
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case reflect.Uint8:
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return &uint8Codec{}, nil
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case reflect.Uint16:
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return &uint16Codec{}, nil
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case reflect.Uint32:
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return &uint32Codec{}, nil
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case reflect.Uint64:
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return &uint64Codec{}, nil
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case reflect.Float32:
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return &float32Codec{}, nil
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case reflect.Float64:
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return &float64Codec{}, nil
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case reflect.Bool:
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return &boolCodec{}, nil
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case reflect.Interface:
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if typ.NumMethod() == 0 {
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return &emptyInterfaceCodec{}, nil
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} else {
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return &nonEmptyInterfaceCodec{}, nil
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}
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case reflect.Struct:
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return prefix(fmt.Sprintf("[%s]", typ.String())).addToDecoder(decoderOfStruct(cfg, typ))
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case reflect.Array:
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return prefix("[array]").addToDecoder(decoderOfArray(cfg, typ))
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case reflect.Slice:
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return prefix("[slice]").addToDecoder(decoderOfSlice(cfg, typ))
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case reflect.Map:
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return prefix("[map]").addToDecoder(decoderOfMap(cfg, typ))
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case reflect.Ptr:
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return prefix("[optional]").addToDecoder(decoderOfOptional(cfg, typ))
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default:
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return nil, fmt.Errorf("unsupported type: %v", typ)
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}
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}
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func encoderOfType(cfg *frozenConfig, typ reflect.Type) (ValEncoder, error) {
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cacheKey := typ
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encoder := cfg.getEncoderFromCache(cacheKey)
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if encoder != nil {
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return encoder, nil
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}
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encoder = getTypeEncoderFromExtension(typ)
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if encoder != nil {
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cfg.addEncoderToCache(cacheKey, encoder)
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return encoder, nil
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}
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encoder = &placeholderEncoder{cfg: cfg, cacheKey: cacheKey}
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cfg.addEncoderToCache(cacheKey, encoder)
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encoder, err := createEncoderOfType(cfg, typ)
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cfg.addEncoderToCache(cacheKey, encoder)
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return encoder, err
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}
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func createEncoderOfType(cfg *frozenConfig, typ reflect.Type) (ValEncoder, error) {
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if typ.String() == "[]uint8" {
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return &base64Codec{}, nil
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}
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if typ.AssignableTo(jsonRawMessageType) {
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return &jsonRawMessageCodec{}, nil
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}
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if typ.AssignableTo(jsoniterRawMessageType) {
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return &jsoniterRawMessageCodec{}, nil
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}
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if typ.AssignableTo(jsonNumberType) {
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return &jsonNumberCodec{}, nil
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}
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if typ.ConvertibleTo(marshalerType) {
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templateInterface := reflect.New(typ).Elem().Interface()
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var encoder ValEncoder = &marshalerEncoder{extractInterface(templateInterface)}
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if typ.Kind() != reflect.Struct {
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encoder = &optionalEncoder{encoder}
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}
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return encoder, nil
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}
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if typ.ConvertibleTo(anyType) {
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return &anyCodec{}, nil
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}
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kind := typ.Kind()
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switch kind {
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case reflect.String:
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return &stringCodec{}, nil
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case reflect.Int:
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return &intCodec{}, nil
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case reflect.Int8:
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return &int8Codec{}, nil
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case reflect.Int16:
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return &int16Codec{}, nil
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case reflect.Int32:
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return &int32Codec{}, nil
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case reflect.Int64:
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return &int64Codec{}, nil
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case reflect.Uint:
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return &uintCodec{}, nil
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case reflect.Uint8:
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return &uint8Codec{}, nil
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case reflect.Uint16:
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return &uint16Codec{}, nil
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case reflect.Uint32:
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return &uint32Codec{}, nil
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case reflect.Uint64:
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return &uint64Codec{}, nil
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case reflect.Float32:
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return &float32Codec{}, nil
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case reflect.Float64:
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return &float64Codec{}, nil
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case reflect.Bool:
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return &boolCodec{}, nil
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case reflect.Interface:
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if typ.NumMethod() == 0 {
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return &emptyInterfaceCodec{}, nil
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} else {
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return &nonEmptyInterfaceCodec{}, nil
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}
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case reflect.Struct:
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return prefix(fmt.Sprintf("[%s]", typ.String())).addToEncoder(encoderOfStruct(cfg, typ))
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case reflect.Array:
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return prefix("[array]").addToEncoder(encoderOfArray(cfg, typ))
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case reflect.Slice:
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return prefix("[slice]").addToEncoder(encoderOfSlice(cfg, typ))
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case reflect.Map:
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return prefix("[map]").addToEncoder(encoderOfMap(cfg, typ))
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case reflect.Ptr:
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return prefix("[optional]").addToEncoder(encoderOfOptional(cfg, typ))
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default:
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return nil, fmt.Errorf("unsupported type: %v", typ)
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}
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}
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func decoderOfOptional(cfg *frozenConfig, typ reflect.Type) (ValDecoder, error) {
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elemType := typ.Elem()
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decoder, err := decoderOfType(cfg, elemType)
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if err != nil {
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return nil, err
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}
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return &optionalDecoder{elemType, decoder}, nil
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}
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func encoderOfOptional(cfg *frozenConfig, typ reflect.Type) (ValEncoder, error) {
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elemType := typ.Elem()
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elemEncoder, err := encoderOfType(cfg, elemType)
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if err != nil {
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return nil, err
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}
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encoder := &optionalEncoder{elemEncoder}
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if elemType.Kind() == reflect.Map {
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encoder = &optionalEncoder{encoder}
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}
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return encoder, nil
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}
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func decoderOfMap(cfg *frozenConfig, typ reflect.Type) (ValDecoder, error) {
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decoder, err := decoderOfType(cfg, typ.Elem())
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if err != nil {
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return nil, err
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}
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mapInterface := reflect.New(typ).Interface()
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return &mapDecoder{typ, typ.Key(), typ.Elem(), decoder, extractInterface(mapInterface)}, nil
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}
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func extractInterface(val interface{}) emptyInterface {
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return *((*emptyInterface)(unsafe.Pointer(&val)))
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}
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func encoderOfMap(cfg *frozenConfig, typ reflect.Type) (ValEncoder, error) {
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elemType := typ.Elem()
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encoder, err := encoderOfType(cfg, elemType)
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if err != nil {
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return nil, err
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}
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mapInterface := reflect.New(typ).Elem().Interface()
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if cfg.sortMapKeys {
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return &sortKeysMapEncoder{typ, elemType, encoder, *((*emptyInterface)(unsafe.Pointer(&mapInterface)))}, nil
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} else {
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return &mapEncoder{typ, elemType, encoder, *((*emptyInterface)(unsafe.Pointer(&mapInterface)))}, nil
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}
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}
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