route/vendor/github.com/zclconf/go-cty/cty/json/marshal.go

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2017-12-02 23:34:35 +00:00
package json
import (
"bytes"
"encoding/json"
"sort"
"github.com/zclconf/go-cty/cty"
)
func marshal(val cty.Value, t cty.Type, path cty.Path, b *bytes.Buffer) error {
// If we're going to decode as DynamicPseudoType then we need to save
// dynamic type information to recover the real type.
if t == cty.DynamicPseudoType && val.Type() != cty.DynamicPseudoType {
return marshalDynamic(val, path, b)
}
if val.IsNull() {
b.WriteString("null")
return nil
}
if !val.IsKnown() {
return path.NewErrorf("value is not known")
}
// The caller should've guaranteed that the given val is conformant with
// the given type t, so we'll proceed under that assumption here.
switch {
case t.IsPrimitiveType():
switch t {
case cty.String:
json, err := json.Marshal(val.AsString())
if err != nil {
return path.NewErrorf("failed to serialize value: %s", err)
}
b.Write(json)
return nil
case cty.Number:
if val.RawEquals(cty.PositiveInfinity) || val.RawEquals(cty.NegativeInfinity) {
return path.NewErrorf("cannot serialize infinity as JSON")
}
b.WriteString(val.AsBigFloat().Text('f', -1))
return nil
case cty.Bool:
if val.True() {
b.WriteString("true")
} else {
b.WriteString("false")
}
return nil
default:
panic("unsupported primitive type")
}
case t.IsListType(), t.IsSetType():
b.WriteRune('[')
first := true
ety := t.ElementType()
it := val.ElementIterator()
path := append(path, nil) // local override of 'path' with extra element
for it.Next() {
if !first {
b.WriteRune(',')
}
ek, ev := it.Element()
path[len(path)-1] = cty.IndexStep{
Key: ek,
}
err := marshal(ev, ety, path, b)
if err != nil {
return err
}
first = false
}
b.WriteRune(']')
return nil
case t.IsMapType():
b.WriteRune('{')
first := true
ety := t.ElementType()
it := val.ElementIterator()
path := append(path, nil) // local override of 'path' with extra element
for it.Next() {
if !first {
b.WriteRune(',')
}
ek, ev := it.Element()
path[len(path)-1] = cty.IndexStep{
Key: ek,
}
var err error
err = marshal(ek, ek.Type(), path, b)
if err != nil {
return err
}
b.WriteRune(':')
err = marshal(ev, ety, path, b)
if err != nil {
return err
}
first = false
}
b.WriteRune('}')
return nil
case t.IsTupleType():
b.WriteRune('[')
etys := t.TupleElementTypes()
it := val.ElementIterator()
path := append(path, nil) // local override of 'path' with extra element
i := 0
for it.Next() {
if i > 0 {
b.WriteRune(',')
}
ety := etys[i]
ek, ev := it.Element()
path[len(path)-1] = cty.IndexStep{
Key: ek,
}
err := marshal(ev, ety, path, b)
if err != nil {
return err
}
i++
}
b.WriteRune(']')
return nil
case t.IsObjectType():
b.WriteRune('{')
atys := t.AttributeTypes()
path := append(path, nil) // local override of 'path' with extra element
names := make([]string, 0, len(atys))
for k := range atys {
names = append(names, k)
}
sort.Strings(names)
for i, k := range names {
aty := atys[k]
if i > 0 {
b.WriteRune(',')
}
av := val.GetAttr(k)
path[len(path)-1] = cty.GetAttrStep{
Name: k,
}
var err error
err = marshal(cty.StringVal(k), cty.String, path, b)
if err != nil {
return err
}
b.WriteRune(':')
err = marshal(av, aty, path, b)
if err != nil {
return err
}
}
b.WriteRune('}')
return nil
case t.IsCapsuleType():
rawVal := val.EncapsulatedValue()
jsonVal, err := json.Marshal(rawVal)
if err != nil {
return path.NewError(err)
}
b.Write(jsonVal)
return nil
default:
// should never happen
return path.NewErrorf("cannot JSON-serialize %s", t.FriendlyName())
}
}
// marshalDynamic adds an extra wrapping object containing dynamic type
// information for the given value.
func marshalDynamic(val cty.Value, path cty.Path, b *bytes.Buffer) error {
typeJSON, err := MarshalType(val.Type())
if err != nil {
return path.NewErrorf("failed to serialize type: %s", err)
}
b.WriteString(`{"value":`)
marshal(val, val.Type(), path, b)
b.WriteString(`,"type":`)
b.Write(typeJSON)
b.WriteRune('}')
return nil
}