Initial commit

vendor/github.com/emersion/go-imap/responses/authenticate.go

@@ -0,0 +1,72 @@
+package responses
+
+import (
+	"encoding/base64"
+
+	"github.com/emersion/go-imap"
+	"github.com/emersion/go-sasl"
+)
+
+// An AUTHENTICATE response.
+type Authenticate struct {
+	Mechanism       sasl.Client
+	InitialResponse []byte
+	Writer          *imap.Writer
+}
+
+func (r *Authenticate) HandleFrom(hdlr imap.RespHandler) (err error) {
+	w := r.Writer
+
+	// Cancel auth if an error occurs
+	defer (func() {
+		if err != nil {
+			w.Write([]byte("*\r\n"))
+			w.Flush()
+		}
+	})()
+
+	for h := range hdlr {
+		cont, ok := h.Resp.(*imap.ContinuationResp)
+		if !ok {
+			h.Reject()
+			continue
+		}
+		h.Accept()
+
+		// Empty challenge, send initial response as stated in RFC 2222 section 5.1
+		if cont.Info == "" && r.InitialResponse != nil {
+			encoded := base64.StdEncoding.EncodeToString(r.InitialResponse)
+			if _, err = w.Write([]byte(encoded + "\r\n")); err != nil {
+				return
+			}
+			if err = w.Flush(); err != nil {
+				return
+			}
+
+			r.InitialResponse = nil
+			continue
+		}
+
+		var challenge []byte
+		challenge, err = base64.StdEncoding.DecodeString(cont.Info)
+		if err != nil {
+			return
+		}
+
+		var res []byte
+		res, err = r.Mechanism.Next(challenge)
+		if err != nil {
+			return
+		}
+
+		encoded := base64.StdEncoding.EncodeToString(res)
+		if _, err = w.Write([]byte(encoded + "\r\n")); err != nil {
+			return
+		}
+		if err = w.Flush(); err != nil {
+			return
+		}
+	}
+
+	return
+}