Added files.

internal/imapwire/imapwire.go

@@ -0,0 +1,47 @@
+// Package imapwire implements the IMAP wire protocol.
+//
+// The IMAP wire protocol is defined in RFC 9051 section 4.
+package imapwire
+
+import (
+	"fmt"
+)
+
+// ConnSide describes the side of a connection: client or server.
+type ConnSide int
+
+const (
+	ConnSideClient ConnSide = 1 + iota
+	ConnSideServer
+)
+
+// ContinuationRequest is a continuation request.
+//
+// The sender must call either Done or Cancel. The receiver must call Wait.
+type ContinuationRequest struct {
+	done chan struct{}
+	err  error
+	text string
+}
+
+func NewContinuationRequest() *ContinuationRequest {
+	return &ContinuationRequest{done: make(chan struct{})}
+}
+
+func (cont *ContinuationRequest) Cancel(err error) {
+	if err == nil {
+		err = fmt.Errorf("imapwire: continuation request cancelled")
+	}
+	cont.err = err
+	close(cont.done)
+}
+
+func (cont *ContinuationRequest) Done(text string) {
+	cont.text = text
+	close(cont.done)
+}
+
+func (cont *ContinuationRequest) Wait() (string, error) {
+	<-cont.done
+	return cont.text, cont.err
+}