feat(cmd): mv and cp

cmd/mv.go

@@ -0,0 +1,112 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/dgraph-io/badger/v4"
+	"github.com/spf13/cobra"
+)
+
+var cpCmd = &cobra.Command{
+	Use:   "cp FROM[@DB] TO[@DB]",
+	Short: "Make a copy of a key.",
+	Args:  cobra.ExactArgs(2),
+	RunE:  cp,
+}
+
+var mvCmd = &cobra.Command{
+	Use:   "mv FROM[@DB] TO[@DB]",
+	Short: "Move a key between (or within) databases.",
+	Args:  cobra.ExactArgs(2),
+	RunE:  mv,
+}
+
+func cp(cmd *cobra.Command, args []string) error {
+	copy = true
+	return mv(cmd, args)
+}
+
+func mv(cmd *cobra.Command, args []string) error {
+	store := &Store{}
+
+	fromKey, fromDB, err := store.parse(args[0], true)
+	if err != nil {
+		return err
+	}
+	toKey, toDB, err := store.parse(args[1], true)
+	if err != nil {
+		return err
+	}
+
+	var srcVal []byte
+	var srcMeta byte
+	var srcExpires uint64
+	readErr := store.Transaction(TransactionArgs{
+		key:      fmt.Sprintf("%s@%s", fromKey, fromDB),
+		readonly: true,
+		transact: func(tx *badger.Txn, k []byte) error {
+			item, err := tx.Get(k)
+			if err != nil {
+				return err
+			}
+			srcMeta = item.UserMeta()
+			srcExpires = item.ExpiresAt()
+			return item.Value(func(v []byte) error {
+				srcVal = append(srcVal[:0], v...)
+				return nil
+			})
+		},
+	})
+	if readErr != nil {
+		return readErr
+	}
+
+	writeErr := store.Transaction(TransactionArgs{
+		key:      fmt.Sprintf("%s@%s", toKey, toDB),
+		readonly: false,
+		sync:     false,
+		transact: func(tx *badger.Txn, k []byte) error {
+			if !force {
+				if _, err := tx.Get(k); err == nil {
+					return fmt.Errorf("%q already exists; run again with --force to overwrite it", args[1])
+				} else if err != badger.ErrKeyNotFound {
+					return err
+				}
+			}
+			entry := badger.NewEntry(k, srcVal).WithMeta(srcMeta)
+			if srcExpires > 0 {
+				entry.ExpiresAt = srcExpires
+			}
+			return tx.SetEntry(entry)
+		},
+	})
+	if writeErr != nil {
+		return writeErr
+	}
+
+	if copy {
+		return nil
+	}
+
+	return store.Transaction(TransactionArgs{
+		key:      fmt.Sprintf("%s@%s", fromKey, fromDB),
+		readonly: false,
+		sync:     false,
+		transact: func(tx *badger.Txn, k []byte) error {
+			return tx.Delete(k)
+		},
+	})
+}
+
+var (
+	copy  bool = false
+	force bool = false
+)
+
+func init() {
+	mvCmd.Flags().BoolVar(&copy, "copy", false, "Copy instead of move (keeps source)")
+	mvCmd.Flags().BoolVarP(&force, "force", "f", false, "Overwrite destination if it exists")
+	rootCmd.AddCommand(mvCmd)
+	cpCmd.Flags().BoolVarP(&force, "force", "f", false, "Overwrite destination if it exists")
+	rootCmd.AddCommand(cpCmd)
+}