71 lines
1.3 KiB
Go
71 lines
1.3 KiB
Go
package grpc
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
var (
|
|
maxMessageSize = 1024 * 1024 * 4
|
|
maxInt = int(^uint(0) >> 1)
|
|
)
|
|
|
|
func decode(r io.Reader) (uint8, []byte, error) {
|
|
header := make([]byte, 5)
|
|
|
|
// read the header
|
|
if _, err := r.Read(header[:]); err != nil {
|
|
return uint8(0), nil, err
|
|
}
|
|
|
|
// get encoding format e.g compressed
|
|
cf := uint8(header[0])
|
|
|
|
// get message length
|
|
length := binary.BigEndian.Uint32(header[1:])
|
|
|
|
// no encoding format
|
|
if length == 0 {
|
|
return cf, nil, nil
|
|
}
|
|
|
|
//
|
|
if int64(length) > int64(maxInt) {
|
|
return cf, nil, fmt.Errorf("grpc: received message larger than max length allowed on current machine (%d vs. %d)", length, maxInt)
|
|
}
|
|
if int(length) > maxMessageSize {
|
|
return cf, nil, fmt.Errorf("grpc: received message larger than max (%d vs. %d)", length, maxMessageSize)
|
|
}
|
|
|
|
msg := make([]byte, int(length))
|
|
|
|
if _, err := r.Read(msg); err != nil {
|
|
if err == io.EOF {
|
|
err = io.ErrUnexpectedEOF
|
|
}
|
|
return cf, nil, err
|
|
}
|
|
|
|
return cf, msg, nil
|
|
}
|
|
|
|
func encode(cf uint8, buf []byte, w io.Writer) error {
|
|
header := make([]byte, 5)
|
|
|
|
// set compression
|
|
header[0] = byte(cf)
|
|
|
|
// write length as header
|
|
binary.BigEndian.PutUint32(header[1:], uint32(len(buf)))
|
|
|
|
// read the header
|
|
if _, err := w.Write(header[:]); err != nil {
|
|
return err
|
|
}
|
|
|
|
// write the buffer
|
|
_, err := w.Write(buf)
|
|
return err
|
|
}
|