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