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// This file is part of gnunet-go, a GNUnet-implementation in Golang.
// Copyright (C) 2019-2022 Bernd Fix >Y<
//
// gnunet-go is free software: you can redistribute it and/or modify it
// under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// gnunet-go 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
// Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: AGPL3.0-or-later
package transport
import (
"bytes"
"context"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"gnunet/message"
"io"
"github.com/bfix/gospel/data"
)
// WriteMessageDirect writes directly to io.Writer
func WriteMessageDirect(wrt io.Writer, msg message.Message) error {
dwc := &directWriteCloser{wrt}
return WriteMessage(context.Background(), dwc, msg)
}
// WriteMessage to io.WriteCloser
func WriteMessage(ctx context.Context, wrt io.WriteCloser, msg message.Message) (err error) {
// convert message to binary data
var buf []byte
if buf, err = data.Marshal(msg); err != nil {
return err
}
// check message header size and packet size
mh, err := message.GetMsgHeader(buf)
if err != nil {
return err
}
if len(buf) != int(mh.MsgSize) {
return errors.New("WriteMessage: message size mismatch")
}
// watch dog for write operation
go func() {
<-ctx.Done()
wrt.Close()
}()
// perform write operation
var n int
if n, err = wrt.Write(buf); err != nil {
return
}
if n != len(buf) {
err = fmt.Errorf("WriteMessage incomplete (%d of %d)", n, len(buf))
}
return
}
//----------------------------------------------------------------------
// ReadMessageDirect reads directly from io.Reader
func ReadMessageDirect(rdr io.Reader, buf []byte) (msg message.Message, err error) {
drc := &directReadCloser{
rdr: rdr,
}
return ReadMessage(context.Background(), drc, buf)
}
// ReadMessage from io.ReadCloser
func ReadMessage(ctx context.Context, rdr io.ReadCloser, buf []byte) (msg message.Message, err error) {
// watch dog for write operation
go func() {
<-ctx.Done()
rdr.Close()
}()
// get bytes from reader
if buf == nil {
buf = make([]byte, 65536)
}
get := func(pos, count int) (err error) {
var n int
if n, err = rdr.Read(buf[pos : pos+count]); err == nil && n != count {
err = fmt.Errorf("not enough bytes on reader (%d of %d)", n, count)
}
return err
}
// read header first
if err = get(0, 4); err != nil {
return
}
var mh *message.Header
if mh, err = message.GetMsgHeader(buf[:4]); err != nil {
return
}
// get rest of message
if err = get(4, int(mh.MsgSize)-4); err != nil {
return
}
if msg, err = message.NewEmptyMessage(mh.MsgType); err != nil {
return
}
if msg == nil {
err = fmt.Errorf("message{%d} is nil", mh.MsgType)
return
}
err = data.Unmarshal(msg, buf[:mh.MsgSize])
return
}
//----------------------------------------------------------------------
// Dump message
func Dump(msg message.Message, format string) string {
switch format {
case "json":
buf, err := json.Marshal(msg)
if err != nil {
return err.Error()
}
return string(buf)
case "hex":
buf := new(bytes.Buffer)
if err := WriteMessageDirect(buf, msg); err != nil {
return err.Error()
}
return hex.EncodeToString(buf.Bytes())
}
return "unknown message dump format"
}
//----------------------------------------------------------------------
// helper for wrapped ReadCloser/WriteCloser (close is nop)
//----------------------------------------------------------------------
type directReadCloser struct {
rdr io.Reader
}
func (drc *directReadCloser) Read(buf []byte) (int, error) {
return drc.rdr.Read(buf)
}
func (drc *directReadCloser) Close() error {
return nil
}
type directWriteCloser struct {
wrt io.Writer
}
func (dwc *directWriteCloser) Write(buf []byte) (int, error) {
return dwc.wrt.Write(buf)
}
func (dwc *directWriteCloser) Close() error {
return nil
}
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