chord/vendor/github.com/go-json-experiment/json/arshal_inlined.go
2025-03-15 20:42:37 -04:00

229 lines
7.0 KiB
Go

// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package json
import (
"bytes"
"errors"
"io"
"reflect"
"github.com/go-json-experiment/json/internal/jsonflags"
"github.com/go-json-experiment/json/internal/jsonopts"
"github.com/go-json-experiment/json/internal/jsonwire"
"github.com/go-json-experiment/json/jsontext"
)
// This package supports "inlining" a Go struct field, where the contents
// of the serialized field (which must be a JSON object) are treated as if
// they are part of the parent Go struct (which represents a JSON object).
//
// Generally, inlined fields are of a Go struct type, where the fields of the
// nested struct are virtually hoisted up to the parent struct using rules
// similar to how Go embedding works (but operating within the JSON namespace).
//
// However, inlined fields may also be of a Go map type with a string key or
// a jsontext.Value. Such inlined fields are called "fallback" fields since they
// represent any arbitrary JSON object member. Explicitly named fields take
// precedence over the inlined fallback. Only one inlined fallback is allowed.
var errRawInlinedNotObject = errors.New("inlined raw value must be a JSON object")
var jsontextValueType = reflect.TypeFor[jsontext.Value]()
// marshalInlinedFallbackAll marshals all the members in an inlined fallback.
func marshalInlinedFallbackAll(enc *jsontext.Encoder, va addressableValue, mo *jsonopts.Struct, f *structField, insertUnquotedName func([]byte) bool) error {
v := addressableValue{va.Field(f.index0), va.forcedAddr} // addressable if struct value is addressable
if len(f.index) > 0 {
v = v.fieldByIndex(f.index, false)
if !v.IsValid() {
return nil // implies a nil inlined field
}
}
v = v.indirect(false)
if !v.IsValid() {
return nil
}
if v.Type() == jsontextValueType {
// TODO(https://go.dev/issue/62121): Use reflect.Value.AssertTo.
b := *v.Addr().Interface().(*jsontext.Value)
if len(b) == 0 { // TODO: Should this be nil? What if it were all whitespace?
return nil
}
dec := export.GetBufferedDecoder(b)
defer export.PutBufferedDecoder(dec)
xd := export.Decoder(dec)
xd.Flags.Set(jsonflags.AllowDuplicateNames | jsonflags.AllowInvalidUTF8 | 1)
tok, err := dec.ReadToken()
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return newMarshalErrorBefore(enc, v.Type(), err)
}
if tok.Kind() != '{' {
return newMarshalErrorBefore(enc, v.Type(), errRawInlinedNotObject)
}
for dec.PeekKind() != '}' {
// Parse the JSON object name.
var flags jsonwire.ValueFlags
val, err := xd.ReadValue(&flags)
if err != nil {
return newMarshalErrorBefore(enc, v.Type(), err)
}
if insertUnquotedName != nil {
name := jsonwire.UnquoteMayCopy(val, flags.IsVerbatim())
if !insertUnquotedName(name) {
return newDuplicateNameError(enc.StackPointer().Parent(), val, enc.OutputOffset())
}
}
if err := enc.WriteValue(val); err != nil {
return err
}
// Parse the JSON object value.
val, err = xd.ReadValue(&flags)
if err != nil {
return newMarshalErrorBefore(enc, v.Type(), err)
}
if err := enc.WriteValue(val); err != nil {
return err
}
}
if _, err := dec.ReadToken(); err != nil {
return newMarshalErrorBefore(enc, v.Type(), err)
}
if err := xd.CheckEOF(); err != nil {
return newMarshalErrorBefore(enc, v.Type(), err)
}
return nil
} else {
m := v // must be a map[~string]V
n := m.Len()
if n == 0 {
return nil
}
mk := newAddressableValue(m.Type().Key())
mv := newAddressableValue(m.Type().Elem())
marshalKey := func(mk addressableValue) error {
b, err := jsonwire.AppendQuote(enc.UnusedBuffer(), mk.String(), &mo.Flags)
if err != nil {
return newMarshalErrorBefore(enc, m.Type().Key(), err)
}
if insertUnquotedName != nil {
isVerbatim := bytes.IndexByte(b, '\\') < 0
name := jsonwire.UnquoteMayCopy(b, isVerbatim)
if !insertUnquotedName(name) {
return newDuplicateNameError(enc.StackPointer().Parent(), b, enc.OutputOffset())
}
}
return enc.WriteValue(b)
}
marshalVal := f.fncs.marshal
if mo.Marshalers != nil {
marshalVal, _ = mo.Marshalers.(*Marshalers).lookup(marshalVal, mv.Type())
}
if !mo.Flags.Get(jsonflags.Deterministic) || n <= 1 {
for iter := m.MapRange(); iter.Next(); {
mk.SetIterKey(iter)
if err := marshalKey(mk); err != nil {
return err
}
mv.Set(iter.Value())
if err := marshalVal(enc, mv, mo); err != nil {
return err
}
}
} else {
names := getStrings(n)
for i, iter := 0, m.Value.MapRange(); i < n && iter.Next(); i++ {
mk.SetIterKey(iter)
(*names)[i] = mk.String()
}
names.Sort()
for _, name := range *names {
mk.SetString(name)
if err := marshalKey(mk); err != nil {
return err
}
// TODO(https://go.dev/issue/57061): Use mv.SetMapIndexOf.
mv.Set(m.MapIndex(mk.Value))
if err := marshalVal(enc, mv, mo); err != nil {
return err
}
}
putStrings(names)
}
return nil
}
}
// unmarshalInlinedFallbackNext unmarshals only the next member in an inlined fallback.
func unmarshalInlinedFallbackNext(dec *jsontext.Decoder, va addressableValue, uo *jsonopts.Struct, f *structField, quotedName, unquotedName []byte) error {
v := addressableValue{va.Field(f.index0), va.forcedAddr} // addressable if struct value is addressable
if len(f.index) > 0 {
v = v.fieldByIndex(f.index, true)
}
v = v.indirect(true)
if v.Type() == jsontextValueType {
b := v.Addr().Interface().(*jsontext.Value)
if len(*b) == 0 { // TODO: Should this be nil? What if it were all whitespace?
*b = append(*b, '{')
} else {
*b = jsonwire.TrimSuffixWhitespace(*b)
if jsonwire.HasSuffixByte(*b, '}') {
// TODO: When merging into an object for the first time,
// should we verify that it is valid?
*b = jsonwire.TrimSuffixByte(*b, '}')
*b = jsonwire.TrimSuffixWhitespace(*b)
if !jsonwire.HasSuffixByte(*b, ',') && !jsonwire.HasSuffixByte(*b, '{') {
*b = append(*b, ',')
}
} else {
return newUnmarshalErrorAfterWithSkipping(dec, uo, v.Type(), errRawInlinedNotObject)
}
}
*b = append(*b, quotedName...)
*b = append(*b, ':')
val, err := dec.ReadValue()
if err != nil {
return err
}
*b = append(*b, val...)
*b = append(*b, '}')
return nil
} else {
name := string(unquotedName) // TODO: Intern this?
m := v // must be a map[~string]V
if m.IsNil() {
m.Set(reflect.MakeMap(m.Type()))
}
mk := reflect.ValueOf(name)
if mkt := m.Type().Key(); mkt != stringType {
mk = mk.Convert(mkt)
}
mv := newAddressableValue(m.Type().Elem()) // TODO: Cache across calls?
if v2 := m.MapIndex(mk); v2.IsValid() {
mv.Set(v2)
}
unmarshal := f.fncs.unmarshal
if uo.Unmarshalers != nil {
unmarshal, _ = uo.Unmarshalers.(*Unmarshalers).lookup(unmarshal, mv.Type())
}
err := unmarshal(dec, mv, uo)
m.SetMapIndex(mk, mv.Value)
if err != nil {
return err
}
return nil
}
}