package jsoniter import ( "fmt" "github.com/modern-go/reflect2" "reflect" "unsafe" ) // ValDecoder is an internal type registered to cache as needed. // Don't confuse jsoniter.ValDecoder with json.Decoder. // For json.Decoder's adapter, refer to jsoniter.AdapterDecoder(todo link). // // Reflection on type to create decoders, which is then cached // Reflection on value is avoided as we can, as the reflect.Value itself will allocate, with following exceptions // 1. create instance of new value, for example *int will need a int to be allocated // 2. append to slice, if the existing cap is not enough, allocate will be done using Reflect.New // 3. assignment to map, both key and value will be reflect.Value // For a simple struct binding, it will be reflect.Value free and allocation free type ValDecoder interface { Decode(ptr unsafe.Pointer, iter *Iterator) } // ValEncoder is an internal type registered to cache as needed. // Don't confuse jsoniter.ValEncoder with json.Encoder. // For json.Encoder's adapter, refer to jsoniter.AdapterEncoder(todo godoc link). type ValEncoder interface { IsEmpty(ptr unsafe.Pointer) bool Encode(ptr unsafe.Pointer, stream *Stream) } type checkIsEmpty interface { IsEmpty(ptr unsafe.Pointer) bool } type ctx struct { *frozenConfig prefix string encoders map[reflect2.Type]ValEncoder decoders map[reflect2.Type]ValDecoder } func (b *ctx) append(prefix string) *ctx { return &ctx{ frozenConfig: b.frozenConfig, prefix: b.prefix + " " + prefix, encoders: b.encoders, decoders: b.decoders, } } // ReadVal copy the underlying JSON into go interface, same as json.Unmarshal func (iter *Iterator) ReadVal(obj interface{}) { cacheKey := reflect2.RTypeOf(obj) decoder := iter.cfg.getDecoderFromCache(cacheKey) if decoder == nil { typ := reflect2.TypeOf(obj) if typ.Kind() != reflect.Ptr { iter.ReportError("ReadVal", "can only unmarshal into pointer") return } decoder = iter.cfg.DecoderOf(typ) } ptr := reflect2.PtrOf(obj) if ptr == nil { iter.ReportError("ReadVal", "can not read into nil pointer") return } decoder.Decode(ptr, iter) } // WriteVal copy the go interface into underlying JSON, same as json.Marshal func (stream *Stream) WriteVal(val interface{}) { if nil == val { stream.WriteNil() return } cacheKey := reflect2.RTypeOf(val) encoder := stream.cfg.getEncoderFromCache(cacheKey) if encoder == nil { typ := reflect2.TypeOf(val) encoder = stream.cfg.EncoderOf(typ) } encoder.Encode(reflect2.PtrOf(val), stream) } func (cfg *frozenConfig) DecoderOf(typ reflect2.Type) ValDecoder { cacheKey := typ.RType() decoder := cfg.getDecoderFromCache(cacheKey) if decoder != nil { return decoder } ctx := &ctx{ frozenConfig: cfg, prefix: "", decoders: map[reflect2.Type]ValDecoder{}, encoders: map[reflect2.Type]ValEncoder{}, } ptrType := typ.(*reflect2.UnsafePtrType) decoder = decoderOfType(ctx, ptrType.Elem()) cfg.addDecoderToCache(cacheKey, decoder) return decoder } func decoderOfType(ctx *ctx, typ reflect2.Type) ValDecoder { decoder := getTypeDecoderFromExtension(ctx, typ) if decoder != nil { return decoder } decoder = createDecoderOfType(ctx, typ) for _, extension := range extensions { decoder = extension.DecorateDecoder(typ, decoder) } for _, extension := range ctx.extensions { decoder = extension.DecorateDecoder(typ, decoder) } return decoder } func createDecoderOfType(ctx *ctx, typ reflect2.Type) ValDecoder { decoder := ctx.decoders[typ] if decoder != nil { return decoder } placeholder := &placeholderDecoder{} ctx.decoders[typ] = placeholder decoder = _createDecoderOfType(ctx, typ) placeholder.decoder = decoder return decoder } func _createDecoderOfType(ctx *ctx, typ reflect2.Type) ValDecoder { decoder := createDecoderOfJsonRawMessage(ctx, typ) if decoder != nil { return decoder } decoder = createDecoderOfJsonNumber(ctx, typ) if decoder != nil { return decoder } decoder = createDecoderOfMarshaler(ctx, typ) if decoder != nil { return decoder } decoder = createDecoderOfAny(ctx, typ) if decoder != nil { return decoder } decoder = createDecoderOfNative(ctx, typ) if decoder != nil { return decoder } switch typ.Kind() { case reflect.Interface: ifaceType, isIFace := typ.(*reflect2.UnsafeIFaceType) if isIFace { return &ifaceDecoder{valType: ifaceType} } return &efaceDecoder{} case reflect.Struct: return decoderOfStruct(ctx, typ) case reflect.Array: return decoderOfArray(ctx, typ) case reflect.Slice: return decoderOfSlice(ctx, typ) case reflect.Map: return decoderOfMap(ctx, typ) case reflect.Ptr: return decoderOfOptional(ctx, typ) default: return &lazyErrorDecoder{err: fmt.Errorf("%s%s is unsupported type", ctx.prefix, typ.String())} } } func (cfg *frozenConfig) EncoderOf(typ reflect2.Type) ValEncoder { cacheKey := typ.RType() encoder := cfg.getEncoderFromCache(cacheKey) if encoder != nil { return encoder } ctx := &ctx{ frozenConfig: cfg, prefix: "", decoders: map[reflect2.Type]ValDecoder{}, encoders: map[reflect2.Type]ValEncoder{}, } encoder = encoderOfType(ctx, typ) if typ.LikePtr() { encoder = &onePtrEncoder{encoder} } cfg.addEncoderToCache(cacheKey, encoder) return encoder } type onePtrEncoder struct { encoder ValEncoder } func (encoder *onePtrEncoder) IsEmpty(ptr unsafe.Pointer) bool { return encoder.encoder.IsEmpty(unsafe.Pointer(&ptr)) } func (encoder *onePtrEncoder) Encode(ptr unsafe.Pointer, stream *Stream) { encoder.encoder.Encode(unsafe.Pointer(&ptr), stream) } func encoderOfType(ctx *ctx, typ reflect2.Type) ValEncoder { encoder := getTypeEncoderFromExtension(ctx, typ) if encoder != nil { return encoder } encoder = createEncoderOfType(ctx, typ) for _, extension := range extensions { encoder = extension.DecorateEncoder(typ, encoder) } for _, extension := range ctx.extensions { encoder = extension.DecorateEncoder(typ, encoder) } return encoder } func createEncoderOfType(ctx *ctx, typ reflect2.Type) ValEncoder { encoder := ctx.encoders[typ] if encoder != nil { return encoder } placeholder := &placeholderEncoder{} ctx.encoders[typ] = placeholder encoder = _createEncoderOfType(ctx, typ) placeholder.encoder = encoder return encoder } func _createEncoderOfType(ctx *ctx, typ reflect2.Type) ValEncoder { encoder := createEncoderOfJsonRawMessage(ctx, typ) if encoder != nil { return encoder } encoder = createEncoderOfJsonNumber(ctx, typ) if encoder != nil { return encoder } encoder = createEncoderOfMarshaler(ctx, typ) if encoder != nil { return encoder } encoder = createEncoderOfAny(ctx, typ) if encoder != nil { return encoder } encoder = createEncoderOfNative(ctx, typ) if encoder != nil { return encoder } kind := typ.Kind() switch kind { case reflect.Interface: return &dynamicEncoder{typ} case reflect.Struct: return encoderOfStruct(ctx, typ) case reflect.Array: return encoderOfArray(ctx, typ) case reflect.Slice: return encoderOfSlice(ctx, typ) case reflect.Map: return encoderOfMap(ctx, typ) case reflect.Ptr: return encoderOfOptional(ctx, typ) default: return &lazyErrorEncoder{err: fmt.Errorf("%s%s is unsupported type", ctx.prefix, typ.String())} } } type lazyErrorDecoder struct { err error } func (decoder *lazyErrorDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) { if iter.WhatIsNext() != NilValue { if iter.Error == nil { iter.Error = decoder.err } } else { iter.Skip() } } type lazyErrorEncoder struct { err error } func (encoder *lazyErrorEncoder) Encode(ptr unsafe.Pointer, stream *Stream) { if ptr == nil { stream.WriteNil() } else if stream.Error == nil { stream.Error = encoder.err } } func (encoder *lazyErrorEncoder) IsEmpty(ptr unsafe.Pointer) bool { return false } type placeholderDecoder struct { decoder ValDecoder } func (decoder *placeholderDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) { decoder.decoder.Decode(ptr, iter) } type placeholderEncoder struct { encoder ValEncoder } func (encoder *placeholderEncoder) Encode(ptr unsafe.Pointer, stream *Stream) { encoder.encoder.Encode(ptr, stream) } func (encoder *placeholderEncoder) IsEmpty(ptr unsafe.Pointer) bool { return encoder.encoder.IsEmpty(ptr) }