imap: add LIST-STATUS extension

Add IMAP extension LIST-STATUS handling to IMAP worker.

Reference: https://www.rfc-editor.org/rfc/rfc5819.html
Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>

1 files changed, 149 insertions, 0 deletions

diff --git a/worker/imap/extensions/liststatus.go b/worker/imap/extensions/liststatus.go
new file mode 100644
index 00000000..44b93a76
--- /dev/null
+++ b/worker/imap/extensions/liststatus.go
@@ -0,0 +1,149 @@
+package extensions
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/emersion/go-imap"
+	"github.com/emersion/go-imap/client"
+	"github.com/emersion/go-imap/responses"
+	"github.com/emersion/go-imap/utf7"
+)
+
+// A LIST-STATUS client
+type ListStatusClient struct {
+	c *client.Client
+}
+
+func NewListStatusClient(c *client.Client) *ListStatusClient {
+	return &ListStatusClient{c}
+}
+
+// SupportListStatus checks if the server supports the LIST-STATUS extension.
+func (c *ListStatusClient) SupportListStatus() (bool, error) {
+	return c.c.Support("LIST-STATUS")
+}
+
+// ListStatus performs a LIST-STATUS command, listing mailboxes and also
+// retrieving the requested status items. A nil channel can be passed in order
+// to only retrieve the STATUS responses
+func (c *ListStatusClient) ListStatus(
+	ref string,
+	name string,
+	items []imap.StatusItem,
+	ch chan *imap.MailboxInfo,
+) ([]*imap.MailboxStatus, error) {
+	if ch != nil {
+		defer close(ch)
+	}
+
+	if c.c.State() != imap.AuthenticatedState && c.c.State() != imap.SelectedState {
+		return nil, client.ErrNotLoggedIn
+	}
+
+	cmd := &ListStatusCommand{
+		Reference: ref,
+		Mailbox:   name,
+		Items:     items,
+	}
+	res := &ListStatusResponse{Mailboxes: ch}
+
+	status, err := c.c.Execute(cmd, res)
+	if err != nil {
+		return nil, err
+	}
+	return res.Statuses, status.Err()
+}
+
+// ListStatusCommand is a LIST command, as defined in RFC 3501 section 6.3.8. If
+// Subscribed is set to true, LSUB will be used instead. Mailbox statuses will
+// be returned if Items is not nil
+type ListStatusCommand struct {
+	Reference string
+	Mailbox   string
+
+	Subscribed bool
+	Items      []imap.StatusItem
+}
+
+func (cmd *ListStatusCommand) Command() *imap.Command {
+	name := "LIST"
+	if cmd.Subscribed {
+		name = "LSUB"
+	}
+
+	enc := utf7.Encoding.NewEncoder()
+	ref, _ := enc.String(cmd.Reference)
+	mailbox, _ := enc.String(cmd.Mailbox)
+
+	items := make([]string, len(cmd.Items))
+	if cmd.Items != nil {
+		for i, item := range cmd.Items {
+			items[i] = string(item)
+		}
+	}
+
+	args := fmt.Sprintf("RETURN (STATUS (%s))", strings.Join(items, " "))
+	return &imap.Command{
+		Name:      name,
+		Arguments: []interface{}{ref, mailbox, imap.RawString(args)},
+	}
+}
+
+// A LIST-STATUS response
+type ListStatusResponse struct {
+	Mailboxes  chan *imap.MailboxInfo
+	Subscribed bool
+	Statuses   []*imap.MailboxStatus
+}
+
+func (r *ListStatusResponse) Name() string {
+	if r.Subscribed {
+		return "LSUB"
+	} else {
+		return "LIST"
+	}
+}
+
+func (r *ListStatusResponse) Handle(resp imap.Resp) error {
+	name, _, ok := imap.ParseNamedResp(resp)
+	if !ok {
+		return responses.ErrUnhandled
+	}
+	switch name {
+	case "LIST":
+		if r.Mailboxes == nil {
+			return nil
+		}
+		res := responses.List{Mailboxes: r.Mailboxes}
+		return res.Handle(resp)
+	case "STATUS":
+		res := responses.Status{
+			Mailbox: new(imap.MailboxStatus),
+		}
+		err := res.Handle(resp)
+		if err != nil {
+			return err
+		}
+		r.Statuses = append(r.Statuses, res.Mailbox)
+	default:
+		return responses.ErrUnhandled
+	}
+
+	return nil
+}
+
+func (r *ListStatusResponse) WriteTo(w *imap.Writer) error {
+	respName := r.Name()
+
+	for mbox := range r.Mailboxes {
+		fields := []interface{}{imap.RawString(respName)}
+		fields = append(fields, mbox.Format()...)
+
+		resp := imap.NewUntaggedResp(fields)
+		if err := resp.WriteTo(w); err != nil {
+			return err
+		}
+	}
+	return nil
+}