Update vendor/

vendor/github.com/emersion/go-message/writer.go

@@ -0,0 +1,116 @@
+package message
+
+import (
+	"errors"
+	"io"
+	"mime/multipart"
+	"net/textproto"
+	"sort"
+	"strings"
+)
+
+// From https://golang.org/src/mime/multipart/writer.go?s=2140:2215#L76
+func writeHeader(w io.Writer, header Header) error {
+	keys := make([]string, 0, len(header))
+	for k := range header {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	for _, k := range keys {
+		for _, v := range header[k] {
+			if _, err := io.WriteString(w, formatHeaderField(k, v)); err != nil {
+				return err
+			}
+		}
+	}
+	_, err := io.WriteString(w, "\r\n")
+	return err
+}
+
+// A Writer formats entities.
+type Writer struct {
+	w  io.Writer
+	c  io.Closer
+	mw *multipart.Writer
+}
+
+// newWriter creates a new Writer writing to w with the provided header. Nothing
+// is written to w when it is called. header is modified in-place.
+func newWriter(w io.Writer, header Header) *Writer {
+	ww := &Writer{w: w}
+
+	mediaType, mediaParams, _ := header.ContentType()
+	if strings.HasPrefix(mediaType, "multipart/") {
+		ww.mw = multipart.NewWriter(ww.w)
+
+		// Do not set ww's io.Closer for now: if this is a multipart entity but
+		// CreatePart is not used (only Write is used), then the final boundary
+		// is expected to be written by the user too. In this case, ww.Close
+		// shouldn't write the final boundary.
+
+		if mediaParams["boundary"] != "" {
+			ww.mw.SetBoundary(mediaParams["boundary"])
+		} else {
+			mediaParams["boundary"] = ww.mw.Boundary()
+			header.SetContentType(mediaType, mediaParams)
+		}
+
+		header.Del("Content-Transfer-Encoding")
+	} else {
+		wc := encodingWriter(header.Get("Content-Transfer-Encoding"), ww.w)
+		ww.w = wc
+		ww.c = wc
+	}
+
+	return ww
+}
+
+// CreateWriter creates a new Writer writing to w. If header contains an
+// encoding, data written to the Writer will automatically be encoded with it.
+func CreateWriter(w io.Writer, header Header) (*Writer, error) {
+	ww := newWriter(w, header)
+	if err := writeHeader(w, header); err != nil {
+		return nil, err
+	}
+	return ww, nil
+}
+
+// Write implements io.Writer.
+func (w *Writer) Write(b []byte) (int, error) {
+	return w.w.Write(b)
+}
+
+// Close implements io.Closer.
+func (w *Writer) Close() error {
+	if w.c != nil {
+		return w.c.Close()
+	}
+	return nil
+}
+
+// CreatePart returns a Writer to a new part in this multipart entity. If this
+// entity is not multipart, it fails. The body of the part should be written to
+// the returned io.WriteCloser.
+func (w *Writer) CreatePart(header Header) (*Writer, error) {
+	if w.mw == nil {
+		return nil, errors.New("cannot create a part in a non-multipart message")
+	}
+
+	if w.c == nil {
+		// We know that the user calls CreatePart so Close should write the final
+		// boundary
+		w.c = w.mw
+	}
+
+	// cw -> ww -> pw -> w.mw -> w.w
+
+	ww := &struct{ io.Writer }{nil}
+	cw := newWriter(ww, header)
+	pw, err := w.mw.CreatePart(textproto.MIMEHeader(header))
+	if err != nil {
+		return nil, err
+	}
+
+	ww.Writer = pw
+	return cw, nil
+}