1 files changed, 33 insertions, 0 deletions
diff --git a/eth/downloader/modes.go b/eth/downloader/modes.go
index ae3c43888..8ecdf91f1 100644
--- a/eth/downloader/modes.go
+++ b/eth/downloader/modes.go
@@ -16,6 +16,8 @@
 
 package downloader
 
+import "fmt"
+
 // SyncMode represents the synchronisation mode of the downloader.
 type SyncMode int
 
@@ -25,6 +27,10 @@ const (
 	LightSync                 // Download only the headers and terminate afterwards
 )
 
+func (mode SyncMode) IsValid() bool {
+	return mode >= FullSync && mode <= LightSync
+}
+
 // String implements the stringer interface.
 func (mode SyncMode) String() string {
 	switch mode {
@@ -38,3 +44,30 @@ func (mode SyncMode) String() string {
 		return "unknown"
 	}
 }
+
+func (mode SyncMode) MarshalText() ([]byte, error) {
+	switch mode {
+	case FullSync:
+		return []byte("full"), nil
+	case FastSync:
+		return []byte("fast"), nil
+	case LightSync:
+		return []byte("light"), nil
+	default:
+		return nil, fmt.Errorf("unknown sync mode %d", mode)
+	}
+}
+
+func (mode *SyncMode) UnmarshalText(text []byte) error {
+	switch string(text) {
+	case "full":
+		*mode = FullSync
+	case "fast":
+		*mode = FastSync
+	case "light":
+		*mode = LightSync
+	default:
+		return fmt.Errorf(`unknown sync mode %q, want "full", "fast" or "light"`, text)
+	}
+	return nil
+}