Add decrypt, refactor

restorer.go

@@ -0,0 +1,100 @@
+package khepri
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/fd0/khepri/backend"
+)
+
+type Restorer struct {
+	be  backend.Server
+	key *Key
+	ch  *ContentHandler
+	sn  *Snapshot
+
+	Error  func(dir string, node *Node, err error) error
+	Filter func(item string, node *Node) bool
+}
+
+// NewRestorer creates a restorer preloaded with the content from the snapshot snid.
+func NewRestorer(be backend.Server, key *Key, snid backend.ID) (*Restorer, error) {
+	r := &Restorer{
+		be:  be,
+		key: key,
+	}
+
+	var err error
+	r.ch, err = NewContentHandler(be, key)
+	if err != nil {
+		return nil, err
+	}
+
+	r.sn, err = r.ch.LoadSnapshot(snid)
+	if err != nil {
+		return nil, err
+	}
+
+	// abort on all errors
+	r.Error = func(string, *Node, error) error { return err }
+	// allow all files
+	r.Filter = func(string, *Node) bool { return true }
+
+	return r, nil
+}
+
+func (res *Restorer) to(dir string, tree_id backend.ID) error {
+	tree := Tree{}
+	err := res.ch.LoadJSON(backend.Tree, tree_id, &tree)
+	if err != nil {
+		return res.Error(dir, nil, err)
+	}
+
+	for _, node := range tree {
+		p := filepath.Join(dir, node.Name)
+		if !res.Filter(p, node) {
+			continue
+		}
+
+		err := node.CreateAt(res.ch, p)
+		if err != nil {
+			err = res.Error(p, node, err)
+			if err != nil {
+				return err
+			}
+		}
+
+		if node.Type == "dir" {
+			if node.Subtree == nil {
+				return errors.New(fmt.Sprintf("Dir without subtree in tree %s", tree_id))
+			}
+
+			err = res.to(p, node.Subtree)
+			if err != nil {
+				err = res.Error(p, node, err)
+				if err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+// RestoreTo creates the directories and files in the snapshot below dir.
+// Before an item is created, res.Filter is called.
+func (res *Restorer) RestoreTo(dir string) error {
+	err := os.MkdirAll(dir, 0700)
+	if err != nil && err != os.ErrExist {
+		return err
+	}
+
+	return res.to(dir, res.sn.Content)
+}
+
+func (res *Restorer) Snapshot() *Snapshot {
+	return res.sn
+}