Function constructStructType

json/codec.go:477–517

(t reflect.Type, seen map[reflect.Type]*structType, canAddr bool)

}

func constructStructType(t reflect.Type, seen map[reflect.Type]*structType, canAddr bool) *structType {
	// Used for preventing infinite recursion on types that have pointers to
	// themselves.
	st := seen[t]

	if st == nil {
		st = &structType{
			fields:      make([]structField, 0, t.NumField()),
			fieldsIndex: make(map[string]*structField),
			ficaseIndex: make(map[string]*structField),
			typ:         t,
		}

		seen[t] = st
		st.fields = appendStructFields(st.fields, t, 0, seen, canAddr)

		for i := range st.fields {
			f := &st.fields[i]
			s := strings.ToLower(f.name)
			st.fieldsIndex[f.name] = f
			// When there is ambiguity because multiple fields have the same
			// case-insensitive representation, the first field must win.
			if _, exists := st.ficaseIndex[s]; !exists {
				st.ficaseIndex[s] = f
			}
		}

		// At a certain point the linear scan provided by keyset is less
		// efficient than a map. The 32 was chosen based on benchmarks in the
		// segmentio/asm repo run with an Intel Kaby Lake processor and go1.17.
		if len(st.fields) <= 32 {
			keys := make([][]byte, len(st.fields))
			for i, f := range st.fields {
				keys[i] = []byte(f.name)
			}
			st.keyset = keyset.New(keys)
		}
	}

	return st
}

func constructStructEncodeFunc(st *structType) encodeFunc {
	return func(e encoder, b []byte, p unsafe.Pointer) ([]byte, error) {