415 lines
12 KiB
Go
415 lines
12 KiB
Go
package jsoniter
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import (
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"fmt"
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"reflect"
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"sort"
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"strings"
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"unicode"
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"unsafe"
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)
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var typeDecoders = map[string]ValDecoder{}
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var fieldDecoders = map[string]ValDecoder{}
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var typeEncoders = map[string]ValEncoder{}
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var fieldEncoders = map[string]ValEncoder{}
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var extensions = []Extension{}
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// StructDescriptor describe how should we encode/decode the struct
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type StructDescriptor struct {
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onePtrEmbedded bool
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onePtrOptimization bool
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Type reflect.Type
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Fields []*Binding
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}
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// GetField get one field from the descriptor by its name.
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// Can not use map here to keep field orders.
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func (structDescriptor *StructDescriptor) GetField(fieldName string) *Binding {
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for _, binding := range structDescriptor.Fields {
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if binding.Field.Name == fieldName {
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return binding
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}
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}
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return nil
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}
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// Binding describe how should we encode/decode the struct field
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type Binding struct {
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levels []int
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Field *reflect.StructField
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FromNames []string
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ToNames []string
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Encoder ValEncoder
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Decoder ValDecoder
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}
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// Extension the one for all SPI. Customize encoding/decoding by specifying alternate encoder/decoder.
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// Can also rename fields by UpdateStructDescriptor.
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type Extension interface {
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UpdateStructDescriptor(structDescriptor *StructDescriptor)
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CreateDecoder(typ reflect.Type) ValDecoder
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CreateEncoder(typ reflect.Type) ValEncoder
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DecorateDecoder(typ reflect.Type, decoder ValDecoder) ValDecoder
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DecorateEncoder(typ reflect.Type, encoder ValEncoder) ValEncoder
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}
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// DummyExtension embed this type get dummy implementation for all methods of Extension
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type DummyExtension struct {
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}
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// UpdateStructDescriptor No-op
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func (extension *DummyExtension) UpdateStructDescriptor(structDescriptor *StructDescriptor) {
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}
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// CreateDecoder No-op
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func (extension *DummyExtension) CreateDecoder(typ reflect.Type) ValDecoder {
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return nil
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}
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// CreateEncoder No-op
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func (extension *DummyExtension) CreateEncoder(typ reflect.Type) ValEncoder {
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return nil
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}
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// DecorateDecoder No-op
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func (extension *DummyExtension) DecorateDecoder(typ reflect.Type, decoder ValDecoder) ValDecoder {
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return decoder
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}
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// DecorateEncoder No-op
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func (extension *DummyExtension) DecorateEncoder(typ reflect.Type, encoder ValEncoder) ValEncoder {
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return encoder
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}
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type funcDecoder struct {
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fun DecoderFunc
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}
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func (decoder *funcDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
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decoder.fun(ptr, iter)
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}
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type funcEncoder struct {
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fun EncoderFunc
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isEmptyFunc func(ptr unsafe.Pointer) bool
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}
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func (encoder *funcEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
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encoder.fun(ptr, stream)
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}
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func (encoder *funcEncoder) EncodeInterface(val interface{}, stream *Stream) {
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WriteToStream(val, stream, encoder)
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}
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func (encoder *funcEncoder) IsEmpty(ptr unsafe.Pointer) bool {
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if encoder.isEmptyFunc == nil {
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return false
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}
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return encoder.isEmptyFunc(ptr)
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}
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// DecoderFunc the function form of TypeDecoder
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type DecoderFunc func(ptr unsafe.Pointer, iter *Iterator)
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// EncoderFunc the function form of TypeEncoder
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type EncoderFunc func(ptr unsafe.Pointer, stream *Stream)
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// RegisterTypeDecoderFunc register TypeDecoder for a type with function
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func RegisterTypeDecoderFunc(typ string, fun DecoderFunc) {
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typeDecoders[typ] = &funcDecoder{fun}
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}
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// RegisterTypeDecoder register TypeDecoder for a typ
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func RegisterTypeDecoder(typ string, decoder ValDecoder) {
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typeDecoders[typ] = decoder
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}
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// RegisterFieldDecoderFunc register TypeDecoder for a struct field with function
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func RegisterFieldDecoderFunc(typ string, field string, fun DecoderFunc) {
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RegisterFieldDecoder(typ, field, &funcDecoder{fun})
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}
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// RegisterFieldDecoder register TypeDecoder for a struct field
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func RegisterFieldDecoder(typ string, field string, decoder ValDecoder) {
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fieldDecoders[fmt.Sprintf("%s/%s", typ, field)] = decoder
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}
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// RegisterTypeEncoderFunc register TypeEncoder for a type with encode/isEmpty function
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func RegisterTypeEncoderFunc(typ string, fun EncoderFunc, isEmptyFunc func(unsafe.Pointer) bool) {
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typeEncoders[typ] = &funcEncoder{fun, isEmptyFunc}
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}
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// RegisterTypeEncoder register TypeEncoder for a type
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func RegisterTypeEncoder(typ string, encoder ValEncoder) {
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typeEncoders[typ] = encoder
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}
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// RegisterFieldEncoderFunc register TypeEncoder for a struct field with encode/isEmpty function
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func RegisterFieldEncoderFunc(typ string, field string, fun EncoderFunc, isEmptyFunc func(unsafe.Pointer) bool) {
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RegisterFieldEncoder(typ, field, &funcEncoder{fun, isEmptyFunc})
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}
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// RegisterFieldEncoder register TypeEncoder for a struct field
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func RegisterFieldEncoder(typ string, field string, encoder ValEncoder) {
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fieldEncoders[fmt.Sprintf("%s/%s", typ, field)] = encoder
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}
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// RegisterExtension register extension
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func RegisterExtension(extension Extension) {
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extensions = append(extensions, extension)
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}
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func getTypeDecoderFromExtension(typ reflect.Type) ValDecoder {
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decoder := _getTypeDecoderFromExtension(typ)
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if decoder != nil {
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for _, extension := range extensions {
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decoder = extension.DecorateDecoder(typ, decoder)
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}
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}
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return decoder
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}
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func _getTypeDecoderFromExtension(typ reflect.Type) ValDecoder {
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for _, extension := range extensions {
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decoder := extension.CreateDecoder(typ)
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if decoder != nil {
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return decoder
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}
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}
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typeName := typ.String()
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decoder := typeDecoders[typeName]
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if decoder != nil {
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return decoder
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}
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if typ.Kind() == reflect.Ptr {
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decoder := typeDecoders[typ.Elem().String()]
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if decoder != nil {
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return &OptionalDecoder{typ.Elem(), decoder}
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}
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}
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return nil
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}
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func getTypeEncoderFromExtension(typ reflect.Type) ValEncoder {
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encoder := _getTypeEncoderFromExtension(typ)
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if encoder != nil {
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for _, extension := range extensions {
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encoder = extension.DecorateEncoder(typ, encoder)
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}
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}
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return encoder
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}
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func _getTypeEncoderFromExtension(typ reflect.Type) ValEncoder {
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for _, extension := range extensions {
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encoder := extension.CreateEncoder(typ)
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if encoder != nil {
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return encoder
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}
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}
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typeName := typ.String()
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encoder := typeEncoders[typeName]
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if encoder != nil {
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return encoder
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}
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if typ.Kind() == reflect.Ptr {
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encoder := typeEncoders[typ.Elem().String()]
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if encoder != nil {
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return &OptionalEncoder{encoder}
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}
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}
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return nil
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}
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func describeStruct(cfg *frozenConfig, typ reflect.Type) (*StructDescriptor, error) {
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embeddedBindings := []*Binding{}
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bindings := []*Binding{}
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for i := 0; i < typ.NumField(); i++ {
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field := typ.Field(i)
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tag := field.Tag.Get(cfg.getTagKey())
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tagParts := strings.Split(tag, ",")
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if tag == "-" {
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continue
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}
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if field.Anonymous && (tag == "" || tagParts[0] == "") {
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if field.Type.Kind() == reflect.Struct {
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structDescriptor, err := describeStruct(cfg, field.Type)
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if err != nil {
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return nil, err
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}
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for _, binding := range structDescriptor.Fields {
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binding.levels = append([]int{i}, binding.levels...)
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omitempty := binding.Encoder.(*structFieldEncoder).omitempty
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binding.Encoder = &structFieldEncoder{&field, binding.Encoder, omitempty}
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binding.Decoder = &structFieldDecoder{&field, binding.Decoder}
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embeddedBindings = append(embeddedBindings, binding)
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}
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continue
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} else if field.Type.Kind() == reflect.Ptr && field.Type.Elem().Kind() == reflect.Struct {
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structDescriptor, err := describeStruct(cfg, field.Type.Elem())
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if err != nil {
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return nil, err
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}
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for _, binding := range structDescriptor.Fields {
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binding.levels = append([]int{i}, binding.levels...)
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omitempty := binding.Encoder.(*structFieldEncoder).omitempty
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binding.Encoder = &OptionalEncoder{binding.Encoder}
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binding.Encoder = &structFieldEncoder{&field, binding.Encoder, omitempty}
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binding.Decoder = &deferenceDecoder{field.Type.Elem(), binding.Decoder}
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binding.Decoder = &structFieldDecoder{&field, binding.Decoder}
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embeddedBindings = append(embeddedBindings, binding)
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}
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continue
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}
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}
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fieldNames := calcFieldNames(field.Name, tagParts[0], tag)
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fieldCacheKey := fmt.Sprintf("%s/%s", typ.String(), field.Name)
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decoder := fieldDecoders[fieldCacheKey]
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if decoder == nil {
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var err error
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decoder, err = decoderOfType(cfg, field.Type)
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if len(fieldNames) > 0 && err != nil {
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return nil, err
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}
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}
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encoder := fieldEncoders[fieldCacheKey]
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if encoder == nil {
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var err error
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encoder, err = encoderOfType(cfg, field.Type)
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if len(fieldNames) > 0 && err != nil {
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return nil, err
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}
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// map is stored as pointer in the struct,
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// and treat nil or empty map as empty field
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if encoder != nil && field.Type.Kind() == reflect.Map {
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encoder = &optionalMapEncoder{encoder}
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}
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}
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binding := &Binding{
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Field: &field,
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FromNames: fieldNames,
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ToNames: fieldNames,
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Decoder: decoder,
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Encoder: encoder,
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}
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binding.levels = []int{i}
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bindings = append(bindings, binding)
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}
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return createStructDescriptor(cfg, typ, bindings, embeddedBindings), nil
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}
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func createStructDescriptor(cfg *frozenConfig, typ reflect.Type, bindings []*Binding, embeddedBindings []*Binding) *StructDescriptor {
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onePtrEmbedded := false
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onePtrOptimization := false
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if typ.NumField() == 1 {
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firstField := typ.Field(0)
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switch firstField.Type.Kind() {
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case reflect.Ptr:
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if firstField.Anonymous && firstField.Type.Elem().Kind() == reflect.Struct {
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onePtrEmbedded = true
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}
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fallthrough
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case reflect.Map:
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onePtrOptimization = true
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case reflect.Struct:
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onePtrOptimization = isStructOnePtr(firstField.Type)
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}
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}
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structDescriptor := &StructDescriptor{
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onePtrEmbedded: onePtrEmbedded,
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onePtrOptimization: onePtrOptimization,
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Type: typ,
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Fields: bindings,
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}
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for _, extension := range extensions {
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extension.UpdateStructDescriptor(structDescriptor)
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}
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processTags(structDescriptor, cfg)
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// merge normal & embedded bindings & sort with original order
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allBindings := sortableBindings(append(embeddedBindings, structDescriptor.Fields...))
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sort.Sort(allBindings)
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structDescriptor.Fields = allBindings
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return structDescriptor
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}
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func isStructOnePtr(typ reflect.Type) bool {
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if typ.NumField() == 1 {
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firstField := typ.Field(0)
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switch firstField.Type.Kind() {
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case reflect.Ptr:
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return true
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case reflect.Map:
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return true
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case reflect.Struct:
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return isStructOnePtr(firstField.Type)
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}
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}
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return false
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}
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type sortableBindings []*Binding
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func (bindings sortableBindings) Len() int {
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return len(bindings)
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}
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func (bindings sortableBindings) Less(i, j int) bool {
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left := bindings[i].levels
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right := bindings[j].levels
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k := 0
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for {
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if left[k] < right[k] {
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return true
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} else if left[k] > right[k] {
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return false
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}
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k++
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}
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}
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func (bindings sortableBindings) Swap(i, j int) {
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bindings[i], bindings[j] = bindings[j], bindings[i]
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}
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func processTags(structDescriptor *StructDescriptor, cfg *frozenConfig) {
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for _, binding := range structDescriptor.Fields {
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shouldOmitEmpty := false
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tagParts := strings.Split(binding.Field.Tag.Get(cfg.getTagKey()), ",")
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for _, tagPart := range tagParts[1:] {
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if tagPart == "omitempty" {
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shouldOmitEmpty = true
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} else if tagPart == "string" {
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if binding.Field.Type.Kind() == reflect.String {
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binding.Decoder = &stringModeStringDecoder{binding.Decoder, cfg}
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binding.Encoder = &stringModeStringEncoder{binding.Encoder, cfg}
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} else {
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binding.Decoder = &stringModeNumberDecoder{binding.Decoder}
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binding.Encoder = &stringModeNumberEncoder{binding.Encoder}
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}
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}
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}
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binding.Decoder = &structFieldDecoder{binding.Field, binding.Decoder}
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binding.Encoder = &structFieldEncoder{binding.Field, binding.Encoder, shouldOmitEmpty}
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}
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}
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func calcFieldNames(originalFieldName string, tagProvidedFieldName string, wholeTag string) []string {
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// ignore?
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if wholeTag == "-" {
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return []string{}
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}
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// rename?
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var fieldNames []string
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if tagProvidedFieldName == "" {
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fieldNames = []string{originalFieldName}
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} else {
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fieldNames = []string{tagProvidedFieldName}
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}
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// private?
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isNotExported := unicode.IsLower(rune(originalFieldName[0]))
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if isNotExported {
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fieldNames = []string{}
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}
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return fieldNames
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}
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