Merge support for MOVE extension

Author: emersion

README.md

@@ -136,6 +136,7 @@ includes:
 * [UNSELECT](https://tools.ietf.org/html/rfc3691)
 * [APPENDLIMIT](https://tools.ietf.org/html/rfc7889)
 * [ENABLE](https://tools.ietf.org/html/rfc5161)
+* [MOVE](https://tools.ietf.org/html/rfc6851)
 
 Support for other extensions is provided via separate packages. See below.
 
@@ -151,7 +152,6 @@ to learn how to use them.
 * [ID](https://github.com/ProtonMail/go-imap-id)
 * [IDLE](https://github.com/emersion/go-imap-idle)
 * [METADATA](https://github.com/emersion/go-imap-metadata)
-* [MOVE](https://github.com/emersion/go-imap-move)
 * [NAMESPACE](https://github.com/foxcpp/go-imap-namespace)
 * [QUOTA](https://github.com/emersion/go-imap-quota)
 * [SORT and THREAD](https://github.com/emersion/go-imap-sortthread)

backend/move.go

@@ -0,0 +1,19 @@
+package backend
+
+import (
+	"github.com/emersion/go-imap"
+)
+
+// MoveMailbox is a mailbox that supports moving messages.
+type MoveMailbox interface {
+	Mailbox
+
+	// Move the specified message(s) to the end of the specified destination
+	// mailbox. This means that a new message is created in the target mailbox
+	// with a new UID, the original message is removed from the source mailbox,
+	// and it appears to the client as a single action.
+	//
+	// If the destination mailbox does not exist, a server SHOULD return an error.
+	// It SHOULD NOT automatically create the mailbox.
+	MoveMessages(uid bool, seqset *imap.SeqSet, dest string) error
+}

client/cmd_selected.go

@@ -272,6 +272,73 @@ func (c *Client) UidCopy(seqset *imap.SeqSet, dest string) error {
 	return c.copy(true, seqset, dest)
 }
 
+func (c *Client) move(uid bool, seqset *imap.SeqSet, dest string) error {
+	if c.State() != imap.SelectedState {
+		return ErrNoMailboxSelected
+	}
+
+	if ok, err := c.Support("MOVE"); err != nil {
+		return err
+	} else if !ok {
+		return c.moveFallback(uid, seqset, dest)
+	}
+
+	var cmd imap.Commander = &commands.Move{
+		SeqSet:  seqset,
+		Mailbox: dest,
+	}
+	if uid {
+		cmd = &commands.Uid{Cmd: cmd}
+	}
+
+	if status, err := c.Execute(cmd, nil); err != nil {
+		return err
+	} else {
+		return status.Err()
+	}
+}
+
+// moveFallback uses COPY, STORE and EXPUNGE for servers which don't support
+// MOVE.
+func (c *Client) moveFallback(uid bool, seqset *imap.SeqSet, dest string) error {
+	item := imap.FormatFlagsOp(imap.AddFlags, true)
+	flags := []interface{}{imap.DeletedFlag}
+	if uid {
+		if err := c.UidCopy(seqset, dest); err != nil {
+			return err
+		}
+
+		if err := c.UidStore(seqset, item, flags, nil); err != nil {
+			return err
+		}
+	} else {
+		if err := c.Copy(seqset, dest); err != nil {
+			return err
+		}
+
+		if err := c.Store(seqset, item, flags, nil); err != nil {
+			return err
+		}
+	}
+
+	return c.Expunge(nil)
+}
+
+// Move moves the specified message(s) to the end of the specified destination
+// mailbox.
+//
+// If the server doesn't support the MOVE extension defined in RFC 6851,
+// go-imap will fallback to copy, store and expunge.
+func (c *Client) Move(seqset *imap.SeqSet, dest string) error {
+	return c.move(false, seqset, dest)
+}
+
+// UidMove is identical to Move, but seqset is interpreted as containing unique
+// identifiers instead of message sequence numbers.
+func (c *Client) UidMove(seqset *imap.SeqSet, dest string) error {
+	return c.move(true, seqset, dest)
+}
+
 // Unselect frees server's resources associated with the selected mailbox and
 // returns the server to the authenticated state. This command performs the same
 // actions as Close, except that no messages are permanently removed from the

commands/move.go

@@ -0,0 +1,48 @@
+package commands
+
+import (
+	"errors"
+
+	"github.com/emersion/go-imap"
+	"github.com/emersion/go-imap/utf7"
+)
+
+// A MOVE command.
+// See RFC 6851 section 3.1.
+type Move struct {
+	SeqSet  *imap.SeqSet
+	Mailbox string
+}
+
+func (cmd *Move) Command() *imap.Command {
+	mailbox, _ := utf7.Encoding.NewEncoder().String(cmd.Mailbox)
+
+	return &imap.Command{
+		Name:      "MOVE",
+		Arguments: []interface{}{cmd.SeqSet, mailbox},
+	}
+}
+
+func (cmd *Move) Parse(fields []interface{}) (err error) {
+	if len(fields) < 2 {
+		return errors.New("No enough arguments")
+	}
+
+	seqset, ok := fields[0].(string)
+	if !ok {
+		return errors.New("Invalid sequence set")
+	}
+	if cmd.SeqSet, err = imap.ParseSeqSet(seqset); err != nil {
+		return err
+	}
+
+	mailbox, ok := fields[1].(string)
+	if !ok {
+		return errors.New("Mailbox name must be a string")
+	}
+	if cmd.Mailbox, err = utf7.Encoding.NewDecoder().String(mailbox); err != nil {
+		return err
+	}
+
+	return
+}

server/cmd_selected.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 
 	"github.com/emersion/go-imap"
+	"github.com/emersion/go-imap/backend"
 	"github.com/emersion/go-imap/commands"
 	"github.com/emersion/go-imap/responses"
 )
@@ -294,6 +295,30 @@ func (cmd *Copy) UidHandle(conn Conn) error {
 	return cmd.handle(true, conn)
 }
 
+type Move struct {
+	commands.Move
+}
+
+func (h *Move) handle(uid bool, conn Conn) error {
+	mailbox := conn.Context().Mailbox
+	if mailbox == nil {
+		return ErrNoMailboxSelected
+	}
+
+	if m, ok := mailbox.(backend.MoveMailbox); ok {
+		return m.MoveMessages(uid, h.SeqSet, h.Mailbox)
+	}
+	return errors.New("MOVE extension not supported")
+}
+
+func (h *Move) Handle(conn Conn) error {
+	return h.handle(false, conn)
+}
+
+func (h *Move) UidHandle(conn Conn) error {
+	return h.handle(true, conn)
+}
+
 type Uid struct {
 	commands.Uid
 }

server/conn.go

@@ -163,7 +163,7 @@ func (c *conn) Close() error {
 }
 
 func (c *conn) Capabilities() []string {
-	caps := []string{"IMAP4rev1", "LITERAL+", "SASL-IR", "CHILDREN", "UNSELECT"}
+	caps := []string{"IMAP4rev1", "LITERAL+", "SASL-IR", "CHILDREN", "UNSELECT", "MOVE"}
 
 	appendLimitSet := false
 	if c.ctx.State == imap.AuthenticatedState {

server/server.go

@@ -174,8 +174,9 @@ func New(bkd backend.Backend) *Server {
 			hdlr.Subscribed = true
 			return hdlr
 		},
-		"STATUS": func() Handler { return &Status{} },
-		"APPEND": func() Handler { return &Append{} },
+		"STATUS":   func() Handler { return &Status{} },
+		"APPEND":   func() Handler { return &Append{} },
+		"UNSELECT": func() Handler { return &Unselect{} },
 
 		"CHECK":   func() Handler { return &Check{} },
 		"CLOSE":   func() Handler { return &Close{} },
@@ -184,9 +185,8 @@ func New(bkd backend.Backend) *Server {
 		"FETCH":   func() Handler { return &Fetch{} },
 		"STORE":   func() Handler { return &Store{} },
 		"COPY":    func() Handler { return &Copy{} },
+		"MOVE":    func() Handler { return &Move{} },
 		"UID":     func() Handler { return &Uid{} },
-
-		"UNSELECT": func() Handler { return &Unselect{} },
 	}
 
 	return s
@@ -404,7 +404,7 @@ func (s *Server) Close() error {
 func (s *Server) Enable(extensions ...Extension) {
 	for _, ext := range extensions {
 		// Ignore built-in extensions
-		if ext.Command("UNSELECT") != nil {
+		if ext.Command("UNSELECT") != nil || ext.Command("MOVE") != nil {
 			continue
 		}
 		s.extensions = append(s.extensions, ext)

server/server_test.go

@@ -10,7 +10,7 @@ import (
 )
 
 // Extnesions that are always advertised by go-imap server.
-const builtinExtensions = "LITERAL+ SASL-IR CHILDREN UNSELECT APPENDLIMIT"
+const builtinExtensions = "LITERAL+ SASL-IR CHILDREN UNSELECT MOVE APPENDLIMIT"
 
 func testServer(t *testing.T) (s *server.Server, conn net.Conn) {
 	bkd := memory.New()