/
json.go
145 lines (121 loc) · 2.4 KB
/
json.go
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package mc_json
import (
"bytes"
"encoding/json"
"io"
msgio "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-msgio"
mc "github.com/ipsn/go-ipfs/gxlibs/github.com/multiformats/go-multicodec"
)
var HeaderPath string
var Header []byte
var HeaderMsgioPath string
var HeaderMsgio []byte
func init() {
HeaderPath = "/json"
HeaderMsgioPath = "/json/msgio"
Header = mc.Header([]byte(HeaderPath))
HeaderMsgio = mc.Header([]byte(HeaderMsgioPath))
}
type codec struct {
mc bool
msgio bool
}
func Codec(msgio bool) mc.Codec {
return &codec{mc: false, msgio: msgio}
}
func Multicodec(msgio bool) mc.Multicodec {
return &codec{mc: true, msgio: msgio}
}
func (c *codec) Encoder(w io.Writer) mc.Encoder {
buf := bytes.NewBuffer(nil)
return &encoder{
w: w,
c: c,
buf: buf,
enc: json.NewEncoder(buf),
}
}
func (c *codec) Decoder(r io.Reader) mc.Decoder {
return &decoder{
r: r,
c: c,
}
}
func (c *codec) Header() []byte {
if c.msgio {
return HeaderMsgio
}
return Header
}
type encoder struct {
w io.Writer
c *codec
enc *json.Encoder
buf *bytes.Buffer
}
type decoder struct {
r io.Reader
c *codec
}
func (c *encoder) Encode(v interface{}) error {
defer c.buf.Reset()
w := c.w
if c.c.mc {
// if multicodec, write the header first
if _, err := c.w.Write(c.c.Header()); err != nil {
return err
}
}
if c.c.msgio {
w = msgio.NewWriter(w)
}
// recast to deal with map[interface{}]interface{} case
vr, err := recast(v)
if err != nil {
return err
}
if err := c.enc.Encode(vr); err != nil {
return err
}
_, err = io.Copy(w, c.buf)
return err
}
func (c *decoder) Decode(v interface{}) error {
r := c.r
if c.c.mc {
// if multicodec, consume the header first
if err := mc.ConsumeHeader(c.r, c.c.Header()); err != nil {
return err
}
}
if c.c.msgio {
// need to make a new one per read.
var err error
r, err = msgio.LimitedReader(c.r)
if err != nil {
return err
}
}
return json.NewDecoder(r).Decode(v)
}
func recast(v interface{}) (cv interface{}, err error) {
switch v.(type) {
case map[interface{}]interface{}:
vmi := v.(map[interface{}]interface{})
vms := make(map[string]interface{}, len(vmi))
for k, v2 := range vmi {
ks, ok := k.(string)
if !ok {
return v, mc.ErrType
}
rv2, err := recast(v2)
if err != nil {
return v, err
}
vms[ks] = rv2
}
return vms, nil
default:
return v, nil // hope for the best.
}
}