forked from ProtonMail/proton-bridge
/
mailbox_header.go
71 lines (57 loc) · 1.79 KB
/
mailbox_header.go
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// 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 imap
import (
"bytes"
"strings"
"github.com/ProtonMail/proton-bridge/pkg/message"
"github.com/emersion/go-imap"
)
func filterHeader(header []byte, section *imap.BodySectionName) []byte {
// Empty section.Fields means BODY[HEADER] was requested so we should return the full header.
if len(section.Fields) == 0 {
return header
}
fieldMap := make(map[string]struct{})
for _, field := range section.Fields {
fieldMap[strings.ToLower(field)] = struct{}{}
}
return filterHeaderLines(header, func(field string) bool {
_, ok := fieldMap[strings.ToLower(field)]
if section.NotFields {
ok = !ok
}
return ok
})
}
func filterHeaderLines(header []byte, wantField func(string) bool) []byte {
var res []byte
for _, line := range message.HeaderLines(header) {
if len(bytes.TrimSpace(line)) == 0 {
res = append(res, line...)
} else {
split := bytes.SplitN(line, []byte(": "), 2)
if len(split) != 2 {
continue
}
if wantField(string(bytes.ToLower(split[0]))) {
res = append(res, line...)
}
}
}
return res
}