Add scoped migration acceptance run

backend/04-imap-source.go

@@ -137,9 +137,13 @@ func (m *imapClientMailbox) listMailboxes() ([]imapListMailbox, error) {
 }
 
 func (m *imapClientMailbox) fetchAll(folder string) ([]RawMessage, error) {
-	if _, err := m.c.Select(folder, &imap.SelectOptions{ReadOnly: true}).Wait(); err != nil {
+	selected, err := m.c.Select(folder, &imap.SelectOptions{ReadOnly: true}).Wait()
+	if err != nil {
 		return nil, err
 	}
+	if selected.NumMessages == 0 {
+		return nil, nil
+	}
 
 	section := &imap.FetchItemBodySection{Peek: true}
 	seqSet := imap.SeqSet{}

backend/07-migrate.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"path/filepath"
+	"strings"
 	"time"
 )
 
@@ -22,6 +23,14 @@ import (
 // name = Konto-Name oder "all". watch = true -> Delta-Schleife bis Abbruch
 // (Cutover-Fenster), sonst einmaliger Durchlauf.
 func RunMigration(name string, watch bool, interval time.Duration) error {
+	return runMigration(name, watch, interval, nil)
+}
+
+func RunMigrationFolders(name string, folders []string) error {
+	return runMigration(name, false, 0, selectedFolderSet(folders))
+}
+
+func runMigration(name string, watch bool, interval time.Duration, selectedFolders map[string]bool) error {
 	if interval <= 0 {
 		interval = 60 * time.Second
 	}
@@ -45,7 +54,7 @@ func RunMigration(name string, watch bool, interval time.Duration) error {
 				if !a.Active {
 					continue
 				}
-				if err := migrateAccount(a); err != nil {
+				if err := migrateAccount(a, selectedFolders); err != nil {
 					if !watch {
 						return err
 					}
@@ -62,7 +71,7 @@ func RunMigration(name string, watch bool, interval time.Duration) error {
 }
 
 // migrateAccount fuehrt einen einzelnen Umzug aus (ein Durchlauf).
-func migrateAccount(a Account) error {
+func migrateAccount(a Account, selectedFolders map[string]bool) error {
 	if a.ID == 0 {
 		stored, err := GetAccount(a.Name)
 		if err != nil {
@@ -102,6 +111,9 @@ func migrateAccount(a Account) error {
 	}
 	total, done, errs := 0, 0, 0
 	for _, folder := range folders {
+		if len(selectedFolders) > 0 && !selectedFolders[folder.Name] {
+			continue
+		}
 		dstFolder := MapSourceToTarget(folder.Name, folder.Attrs, folder.Delim, dst.Delim(), targets, "")
 		if dstFolder == "" {
 			dstFolder = folder.Name
@@ -165,6 +177,17 @@ func migrateAccount(a Account) error {
 	return nil
 }
 
+func selectedFolderSet(folders []string) map[string]bool {
+	out := make(map[string]bool, len(folders))
+	for _, folder := range folders {
+		folder = strings.TrimSpace(folder)
+		if folder != "" {
+			out[folder] = true
+		}
+	}
+	return out
+}
+
 func CheckAccount(name string) error {
 	a, err := GetAccount(name)
 	if err != nil {