Add --batch-size command-line flag

imap_clean.go

@@ -26,6 +26,7 @@ var (
 	dryRun            = flag.Bool("dry-run", false, "do not actually delete messages")
 	folder            = flag.String("folder", "INBOX", "remote IMAP folder")
 	verbose           = flag.Bool("verbose", false, "print additional debug messages")
+	batchSize         = flag.Int("batch-size", 100, "deletion batch size")
 )
 
 func vlog(fmt string, args ...interface{}) {
@@ -92,11 +93,9 @@ func buildCriteria() (*imap.SearchCriteria, error) {
 	return crit, nil
 }
 
-const batchSize = 200
-
 func uidBatch(c *client.Client, uids []uint32, f func([]uint32) error) error {
-	for i := 0; i < len(uids); i += batchSize {
-		j := i + batchSize
+	for i := 0; i < len(uids); i += *batchSize {
+		j := i + *batchSize
 		if j > len(uids) {
 			j = len(uids)
 		}