Files
proton-bridge/pkg/message/scanner.go
2021-05-26 14:48:46 +00:00

97 lines
2.1 KiB
Go

// Copyright (c) 2021 Proton Technologies AG
//
// This file is part of ProtonMail Bridge.
//
// ProtonMail Bridge 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.
//
// ProtonMail Bridge 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 ProtonMail Bridge. If not, see <https://www.gnu.org/licenses/>.
package message
import (
"bufio"
"bytes"
"errors"
"io"
)
type partScanner struct {
r *bufio.Reader
boundary string
progress int
}
type part struct {
b []byte
offset int
}
func newPartScanner(r io.Reader, boundary string) (*partScanner, error) {
scanner := &partScanner{r: bufio.NewReader(r), boundary: boundary}
if _, _, err := scanner.readToBoundary(); err != nil {
return nil, err
}
return scanner, nil
}
func (s *partScanner) scanAll() ([]part, error) {
var parts []part
for {
offset := s.progress
b, more, err := s.readToBoundary()
if err != nil {
return nil, err
}
if !more {
return parts, nil
}
parts = append(parts, part{b: b, offset: offset})
}
}
func (s *partScanner) readToBoundary() ([]byte, bool, error) {
var res []byte
for {
line, err := s.r.ReadBytes('\n')
if err != nil {
if !errors.Is(err, io.EOF) {
return nil, false, err
}
if len(line) == 0 {
return nil, false, nil
}
}
s.progress += len(line)
switch {
case bytes.HasPrefix(bytes.TrimSpace(line), []byte("--"+s.boundary)):
return bytes.TrimSuffix(bytes.TrimSuffix(res, []byte("\n")), []byte("\r")), true, nil
case bytes.HasSuffix(bytes.TrimSpace(line), []byte(s.boundary+"--")):
return bytes.TrimSuffix(bytes.TrimSuffix(res, []byte("\n")), []byte("\r")), false, nil
default:
res = append(res, line...)
}
}
}