forked from emersion/go-imap
/
bodystructure.go
117 lines (105 loc) · 2.67 KB
/
bodystructure.go
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package backendutil
import (
"bufio"
"bytes"
"io"
"io/ioutil"
"mime"
"strings"
"github.com/artpar/go-imap"
"github.com/emersion/go-message/textproto"
)
type countReader struct {
r io.Reader
bytes uint32
newlines uint32
endsWithLF bool
}
func (r *countReader) Read(b []byte) (int, error) {
n, err := r.r.Read(b)
r.bytes += uint32(n)
if n != 0 {
r.newlines += uint32(bytes.Count(b[:n], []byte{'\n'}))
r.endsWithLF = b[n-1] == '\n'
}
// If the stream does not end with a newline - count missing newline.
if err == io.EOF {
if !r.endsWithLF {
r.newlines++
}
}
return n, err
}
// FetchBodyStructure computes a message's body structure from its content.
func FetchBodyStructure(header textproto.Header, body io.Reader, extended bool) (*imap.BodyStructure, error) {
bs := new(imap.BodyStructure)
mediaType, mediaParams, err := mime.ParseMediaType(header.Get("Content-Type"))
if err == nil {
typeParts := strings.SplitN(mediaType, "/", 2)
bs.MIMEType = typeParts[0]
if len(typeParts) == 2 {
bs.MIMESubType = typeParts[1]
}
bs.Params = mediaParams
} else {
bs.MIMEType = "text"
bs.MIMESubType = "plain"
}
bs.Id = header.Get("Content-Id")
bs.Description = header.Get("Content-Description")
bs.Encoding = header.Get("Content-Transfer-Encoding")
if mr := multipartReader(header, body); mr != nil {
var parts []*imap.BodyStructure
for {
p, err := mr.NextPart()
if err == io.EOF {
break
} else if err != nil {
return nil, err
}
pbs, err := FetchBodyStructure(p.Header, p, extended)
if err != nil {
return nil, err
}
parts = append(parts, pbs)
}
bs.Parts = parts
} else {
countedBody := countReader{r: body}
needLines := false
if bs.MIMEType == "message" && bs.MIMESubType == "rfc822" {
// This will result in double-buffering if body is already a
// bufio.Reader (most likely it is). :\
bufBody := bufio.NewReader(&countedBody)
subMsgHdr, err := textproto.ReadHeader(bufBody)
if err != nil {
return nil, err
}
bs.Envelope, err = FetchEnvelope(subMsgHdr)
if err != nil {
return nil, err
}
bs.BodyStructure, err = FetchBodyStructure(subMsgHdr, bufBody, extended)
if err != nil {
return nil, err
}
needLines = true
} else if bs.MIMEType == "text" {
needLines = true
}
if _, err := io.Copy(ioutil.Discard, &countedBody); err != nil {
return nil, err
}
bs.Size = countedBody.bytes
if needLines {
bs.Lines = countedBody.newlines
}
}
if extended {
bs.Extended = true
bs.Disposition, bs.DispositionParams, _ = mime.ParseMediaType(header.Get("Content-Disposition"))
// TODO: bs.Language, bs.Location
// TODO: bs.MD5
}
return bs, nil
}