Add missing ENABLE command and response

Author: emersion

commands/enable.go

@@ -0,0 +1,23 @@
+package commands
+
+import (
+	"github.com/emersion/go-imap"
+)
+
+// An ENABLE command, defined in RFC 5161 section 3.1.
+type Enable struct {
+	Caps []string
+}
+
+func (cmd *Enable) Command() *imap.Command {
+	return &imap.Command{
+		Name:      "ENABLE",
+		Arguments: imap.FormatStringList(cmd.Caps),
+	}
+}
+
+func (cmd *Enable) Parse(fields []interface{}) error {
+	var err error
+	cmd.Caps, err = imap.ParseStringList(fields)
+	return err
+}

responses/enabled.go

@@ -0,0 +1,33 @@
+package responses
+
+import (
+	"github.com/emersion/go-imap"
+)
+
+// An ENABLED response, defined in RFC 5161 section 3.2.
+type Enabled struct {
+	Caps []string
+}
+
+func (r *Enabled) Handle(resp imap.Resp) error {
+	name, fields, ok := imap.ParseNamedResp(resp)
+	if !ok || name != "ENABLED" {
+		return ErrUnhandled
+	}
+
+	if caps, err := imap.ParseStringList(fields); err != nil {
+		return err
+	} else {
+		r.Caps = append(r.Caps, caps...)
+	}
+
+	return nil
+}
+
+func (r *Enabled) WriteTo(w *imap.Writer) error {
+	fields := []interface{}{imap.RawString("ENABLED")}
+	for _, cap := range r.Caps {
+		fields = append(fields, imap.RawString(cap))
+	}
+	return imap.NewUntaggedResp(fields).WriteTo(w)
+}