Update vendor/

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

@@ -0,0 +1,154 @@
+package message
+
+import (
+	"mime"
+	"net/textproto"
+	"strings"
+
+	"github.com/emersion/go-message/charset"
+)
+
+const maxHeaderLen = 76
+
+func parseHeaderWithParams(s string) (f string, params map[string]string, err error) {
+	f, params, err = mime.ParseMediaType(s)
+	if err != nil {
+		return s, nil, err
+	}
+	for k, v := range params {
+		params[k], _ = charset.DecodeHeader(v)
+	}
+	return
+}
+
+func formatHeaderWithParams(f string, params map[string]string) string {
+	encParams := make(map[string]string)
+	for k, v := range params {
+		encParams[k] = charset.EncodeHeader(v)
+	}
+	return mime.FormatMediaType(f, encParams)
+}
+
+// formatHeaderField formats a header field, ensuring each line is no longer
+// than 76 characters. It tries to fold lines at whitespace characters if
+// possible. If the header contains a word longer than this limit, it will be
+// split.
+func formatHeaderField(k, v string) string {
+	s := k + ": "
+
+	if v == "" {
+		return s + "\r\n"
+	}
+
+	first := true
+	for len(v) > 0 {
+		maxlen := maxHeaderLen
+		if first {
+			maxlen -= len(s)
+		}
+
+		// We'll need to fold before i
+		foldBefore := maxlen + 1
+		foldAt := len(v)
+
+		var folding string
+		if foldBefore > len(v) {
+			// We reached the end of the string
+			if v[len(v)-1] != '\n' {
+				// If there isn't already a trailing CRLF, insert one
+				folding = "\r\n"
+			}
+		} else {
+			// Find the closest whitespace before i
+			foldAt = strings.LastIndexAny(v[:foldBefore], " \t\n")
+			if foldAt == 0 {
+				// The whitespace we found was the previous folding WSP
+				foldAt = foldBefore - 1
+			} else if foldAt < 0 {
+				// We didn't find any whitespace, we have to insert one
+				foldAt = foldBefore - 2
+			}
+
+			switch v[foldAt] {
+			case ' ', '\t':
+				if v[foldAt-1] != '\n' {
+					folding = "\r\n" // The next char will be a WSP, don't need to insert one
+				}
+			case '\n':
+				folding = "" // There is already a CRLF, nothing to do
+			default:
+				folding = "\r\n " // Another char, we need to insert CRLF + WSP
+			}
+		}
+
+		s += v[:foldAt] + folding
+		v = v[foldAt:]
+		first = false
+	}
+
+	return s
+}
+
+// A Header represents the key-value pairs in a message header.
+type Header map[string][]string
+
+// Add adds the key, value pair to the header. It appends to any existing values
+// associated with key.
+func (h Header) Add(key, value string) {
+	textproto.MIMEHeader(h).Add(key, value)
+}
+
+// Set sets the header entries associated with key to the single element value.
+// It replaces any existing values associated with key.
+func (h Header) Set(key, value string) {
+	textproto.MIMEHeader(h).Set(key, value)
+}
+
+// Get gets the first value associated with the given key. If there are no
+// values associated with the key, Get returns "".
+func (h Header) Get(key string) string {
+	return textproto.MIMEHeader(h).Get(key)
+}
+
+// Del deletes the values associated with key.
+func (h Header) Del(key string) {
+	textproto.MIMEHeader(h).Del(key)
+}
+
+// ContentType parses the Content-Type header field.
+//
+// If no Content-Type is specified, it returns "text/plain".
+func (h Header) ContentType() (t string, params map[string]string, err error) {
+	v := h.Get("Content-Type")
+	if v == "" {
+		return "text/plain", nil, nil
+	}
+	return parseHeaderWithParams(v)
+}
+
+// SetContentType formats the Content-Type header field.
+func (h Header) SetContentType(t string, params map[string]string) {
+	h.Set("Content-Type", formatHeaderWithParams(t, params))
+}
+
+// ContentDescription parses the Content-Description header field.
+func (h Header) ContentDescription() (string, error) {
+	return charset.DecodeHeader(h.Get("Content-Description"))
+}
+
+// SetContentDescription parses the Content-Description header field.
+func (h Header) SetContentDescription(desc string) {
+	h.Set("Content-Description", charset.EncodeHeader(desc))
+}
+
+// ContentDisposition parses the Content-Disposition header field, as defined in
+// RFC 2183.
+func (h Header) ContentDisposition() (disp string, params map[string]string, err error) {
+	return parseHeaderWithParams(h.Get("Content-Disposition"))
+}
+
+// SetContentDisposition formats the Content-Disposition header field, as
+// defined in RFC 2183.
+func (h Header) SetContentDisposition(disp string, params map[string]string) {
+	h.Set("Content-Disposition", formatHeaderWithParams(disp, params))
+}