ethdb: Implement interface for prefixed operations to the DB (#3536)

ethdb/database.go

@@ -305,3 +305,55 @@ func (b *ldbBatch) Put(key, value []byte) error {
 func (b *ldbBatch) Write() error {
 	return b.db.Write(b.b, nil)
 }
+
+type table struct {
+	db     Database
+	prefix string
+}
+
+// NewTable returns a Database object that prefixes all keys with a given
+// string.
+func NewTable(db Database, prefix string) Database {
+	return &table{
+		db:     db,
+		prefix: prefix,
+	}
+}
+
+func (dt *table) Put(key []byte, value []byte) error {
+	return dt.db.Put(append([]byte(dt.prefix), key...), value)
+}
+
+func (dt *table) Get(key []byte) ([]byte, error) {
+	return dt.db.Get(append([]byte(dt.prefix), key...))
+}
+
+func (dt *table) Delete(key []byte) error {
+	return dt.db.Delete(append([]byte(dt.prefix), key...))
+}
+
+func (dt *table) Close() {
+	// Do nothing; don't close the underlying DB.
+}
+
+type tableBatch struct {
+	batch  Batch
+	prefix string
+}
+
+// NewTableBatch returns a Batch object which prefixes all keys with a given string.
+func NewTableBatch(db Database, prefix string) Batch {
+	return &tableBatch{db.NewBatch(), prefix}
+}
+
+func (dt *table) NewBatch() Batch {
+	return &tableBatch{dt.db.NewBatch(), dt.prefix}
+}
+
+func (tb *tableBatch) Put(key, value []byte) error {
+	return tb.batch.Put(append([]byte(tb.prefix), key...), value)
+}
+
+func (tb *tableBatch) Write() error {
+	return tb.batch.Write()
+}