forked from Silverfish/proton-bridge
57 lines
1.8 KiB
Go
57 lines
1.8 KiB
Go
// Copyright (c) 2020 Proton Technologies AG
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//
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// This file is part of ProtonMail Bridge.
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//
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// ProtonMail Bridge is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// ProtonMail Bridge is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with ProtonMail Bridge. If not, see <https://www.gnu.org/licenses/>.
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package parser
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import (
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"bytes"
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"io"
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)
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const endOfMail = "\r\n.\r\n"
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// endOfMailTrimmer wraps a reader to trim the End-Of-Mail indicator at the end
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// of the input, if present.
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//
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// During SMTP sending of a message, the DATA command indicates that you are
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// about to send the text (or body) of the message. The message text must end
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// with "\r\n.\r\n." I'm 99% sure that these 5 bytes should not be considered
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// part of the message body. However, some mail servers keep them as part of
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// the message, which our parser sometimes doesn't like. Therefore, we strip
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// them if we find them.
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type endOfMailTrimmer struct {
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r io.Reader
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buf bytes.Buffer
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}
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func newEndOfMailTrimmer(r io.Reader) *endOfMailTrimmer {
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return &endOfMailTrimmer{r: r}
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}
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func (r *endOfMailTrimmer) Read(p []byte) (int, error) {
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_, err := io.CopyN(&r.buf, r.r, int64(len(p)+len(endOfMail)-r.buf.Len()))
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if err != nil && err != io.EOF {
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return 0, err
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}
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if err == io.EOF && bytes.HasSuffix(r.buf.Bytes(), []byte(endOfMail)) {
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r.buf.Truncate(r.buf.Len() - len(endOfMail))
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}
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return r.buf.Read(p)
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}
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