// RPC primitives for safcm: basic connection implementation

// Copyright (C) 2021  Simon Ruderich
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package safcm

import (
	"encoding/gob"
	"io"
)

type GobConn struct {
	enc *gob.Encoder
	dec *gob.Decoder
}

func NewGobConn(r io.Reader, w io.Writer) *GobConn {
	return &GobConn{
		enc: gob.NewEncoder(w),
		dec: gob.NewDecoder(r),
	}
}

func (c *GobConn) Send(x Msg) error {
	// & lets Encode send the interface itself and not a concrete type
	// which is necessary to Decode as an interface
	return c.enc.Encode(&x)
}

func (c *GobConn) Recv() (Msg, error) {
	var x Msg
	err := c.dec.Decode(&x)
	if err != nil {
		return nil, err
	}
	return x, nil
}