dispatch/vendor/github.com/mailru/easyjson/helpers.go
2020-05-03 09:05:16 +02:00

109 lines
2.9 KiB
Go

// Package easyjson contains marshaler/unmarshaler interfaces and helper functions.
package easyjson
import (
"io"
"io/ioutil"
"net/http"
"strconv"
"unsafe"
"github.com/mailru/easyjson/jlexer"
"github.com/mailru/easyjson/jwriter"
)
// Marshaler is an easyjson-compatible marshaler interface.
type Marshaler interface {
MarshalEasyJSON(w *jwriter.Writer)
}
// Marshaler is an easyjson-compatible unmarshaler interface.
type Unmarshaler interface {
UnmarshalEasyJSON(w *jlexer.Lexer)
}
// Optional defines an undefined-test method for a type to integrate with 'omitempty' logic.
type Optional interface {
IsDefined() bool
}
// UnknownsUnmarshaler provides a method to unmarshal unknown struct fileds and save them as you want
type UnknownsUnmarshaler interface {
UnmarshalUnknown(in *jlexer.Lexer, key string)
}
// UnknownsMarshaler provides a method to write additional struct fields
type UnknownsMarshaler interface {
MarshalUnknowns(w *jwriter.Writer, first bool)
}
func isNilInterface(i interface{}) bool {
return (*[2]uintptr)(unsafe.Pointer(&i))[1] == 0
}
// Marshal returns data as a single byte slice. Method is suboptimal as the data is likely to be copied
// from a chain of smaller chunks.
func Marshal(v Marshaler) ([]byte, error) {
if isNilInterface(v) {
return nullBytes, nil
}
w := jwriter.Writer{}
v.MarshalEasyJSON(&w)
return w.BuildBytes()
}
// MarshalToWriter marshals the data to an io.Writer.
func MarshalToWriter(v Marshaler, w io.Writer) (written int, err error) {
if isNilInterface(v) {
return w.Write(nullBytes)
}
jw := jwriter.Writer{}
v.MarshalEasyJSON(&jw)
return jw.DumpTo(w)
}
// MarshalToHTTPResponseWriter sets Content-Length and Content-Type headers for the
// http.ResponseWriter, and send the data to the writer. started will be equal to
// false if an error occurred before any http.ResponseWriter methods were actually
// invoked (in this case a 500 reply is possible).
func MarshalToHTTPResponseWriter(v Marshaler, w http.ResponseWriter) (started bool, written int, err error) {
if isNilInterface(v) {
w.Header().Set("Content-Type", "application/json")
w.Header().Set("Content-Length", strconv.Itoa(len(nullBytes)))
written, err = w.Write(nullBytes)
return true, written, err
}
jw := jwriter.Writer{}
v.MarshalEasyJSON(&jw)
if jw.Error != nil {
return false, 0, jw.Error
}
w.Header().Set("Content-Type", "application/json")
w.Header().Set("Content-Length", strconv.Itoa(jw.Size()))
started = true
written, err = jw.DumpTo(w)
return
}
// Unmarshal decodes the JSON in data into the object.
func Unmarshal(data []byte, v Unmarshaler) error {
l := jlexer.Lexer{Data: data}
v.UnmarshalEasyJSON(&l)
return l.Error()
}
// UnmarshalFromReader reads all the data in the reader and decodes as JSON into the object.
func UnmarshalFromReader(r io.Reader, v Unmarshaler) error {
data, err := ioutil.ReadAll(r)
if err != nil {
return err
}
l := jlexer.Lexer{Data: data}
v.UnmarshalEasyJSON(&l)
return l.Error()
}