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mirror of https://github.com/json-iterator/go.git synced 2024-12-09 08:55:35 +02:00
json-iterator/reflect_optional.go
2018-02-21 12:16:50 +08:00

132 lines
3.4 KiB
Go

package jsoniter
import (
"reflect"
"unsafe"
"github.com/v2pro/plz/reflect2"
)
func decoderOfOptional(cfg *frozenConfig, prefix string, typ reflect.Type) ValDecoder {
elemType := typ.Elem()
decoder := decoderOfType(cfg, prefix, elemType)
if prefix == "" && elemType.Kind() == reflect.Ptr {
return &dereferenceDecoder{reflect2.Type2(elemType), decoder}
}
return &OptionalDecoder{reflect2.Type2(elemType), decoder}
}
func encoderOfOptional(cfg *frozenConfig, prefix string, typ reflect.Type) ValEncoder {
elemType := typ.Elem()
elemEncoder := encoderOfType(cfg, prefix, elemType)
encoder := &OptionalEncoder{elemEncoder}
return encoder
}
type OptionalDecoder struct {
ValueType reflect2.Type
ValueDecoder ValDecoder
}
func (decoder *OptionalDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
if iter.ReadNil() {
*((*unsafe.Pointer)(ptr)) = nil
} else {
if *((*unsafe.Pointer)(ptr)) == nil {
//pointer to null, we have to allocate memory to hold the value
newPtr := decoder.ValueType.UnsafeNew()
decoder.ValueDecoder.Decode(newPtr, iter)
*((*unsafe.Pointer)(ptr)) = newPtr
} else {
//reuse existing instance
decoder.ValueDecoder.Decode(*((*unsafe.Pointer)(ptr)), iter)
}
}
}
type dereferenceDecoder struct {
// only to deference a pointer
valueType reflect2.Type
valueDecoder ValDecoder
}
func (decoder *dereferenceDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
if *((*unsafe.Pointer)(ptr)) == nil {
//pointer to null, we have to allocate memory to hold the value
newPtr := decoder.valueType.UnsafeNew()
decoder.valueDecoder.Decode(newPtr, iter)
*((*unsafe.Pointer)(ptr)) = newPtr
} else {
//reuse existing instance
decoder.valueDecoder.Decode(*((*unsafe.Pointer)(ptr)), iter)
}
}
type OptionalEncoder struct {
ValueEncoder ValEncoder
}
func (encoder *OptionalEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
if *((*unsafe.Pointer)(ptr)) == nil {
stream.WriteNil()
} else {
encoder.ValueEncoder.Encode(*((*unsafe.Pointer)(ptr)), stream)
}
}
func (encoder *OptionalEncoder) IsEmpty(ptr unsafe.Pointer) bool {
return *((*unsafe.Pointer)(ptr)) == nil
}
type dereferenceEncoder struct {
ValueEncoder ValEncoder
}
func (encoder *dereferenceEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
if *((*unsafe.Pointer)(ptr)) == nil {
stream.WriteNil()
} else {
encoder.ValueEncoder.Encode(*((*unsafe.Pointer)(ptr)), stream)
}
}
func (encoder *dereferenceEncoder) IsEmpty(ptr unsafe.Pointer) bool {
dePtr := *((*unsafe.Pointer)(ptr))
if dePtr == nil {
return true
}
return encoder.ValueEncoder.IsEmpty(dePtr)
}
func (encoder *dereferenceEncoder) IsEmbeddedPtrNil(ptr unsafe.Pointer) bool {
deReferenced := *((*unsafe.Pointer)(ptr))
if deReferenced == nil {
return true
}
isEmbeddedPtrNil, converted := encoder.ValueEncoder.(IsEmbeddedPtrNil)
if !converted {
return false
}
fieldPtr := unsafe.Pointer(deReferenced)
return isEmbeddedPtrNil.IsEmbeddedPtrNil(fieldPtr)
}
type referenceEncoder struct {
encoder ValEncoder
}
func (encoder *referenceEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
encoder.encoder.Encode(unsafe.Pointer(&ptr), stream)
}
func (encoder *referenceEncoder) IsEmpty(ptr unsafe.Pointer) bool {
return encoder.encoder.IsEmpty(unsafe.Pointer(&ptr))
}
type referenceDecoder struct {
decoder ValDecoder
}
func (decoder *referenceDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
decoder.decoder.Decode(unsafe.Pointer(&ptr), iter)
}