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restic/restorer.go
2015-05-14 15:58:26 +02:00

117 lines
2.9 KiB
Go

package restic
import (
"fmt"
"os"
"path/filepath"
"syscall"
"github.com/restic/restic/backend"
"github.com/restic/restic/repository"
"github.com/juju/errors"
)
// Restorer is used to restore a snapshot to a directory.
type Restorer struct {
repo *repository.Repository
sn *Snapshot
Error func(dir string, node *Node, err error) error
Filter func(item string, dstpath string, node *Node) bool
}
var restorerAbortOnAllErrors = func(str string, node *Node, err error) error { return err }
// NewRestorer creates a restorer preloaded with the content from the snapshot id.
func NewRestorer(repo *repository.Repository, id backend.ID) (*Restorer, error) {
r := &Restorer{repo: repo, Error: restorerAbortOnAllErrors}
var err error
r.sn, err = LoadSnapshot(repo, id)
if err != nil {
return nil, errors.Annotate(err, "load snapshot for restorer")
}
return r, nil
}
func (res *Restorer) restoreTo(dst string, dir string, treeID backend.ID) error {
tree, err := LoadTree(res.repo, treeID)
if err != nil {
return res.Error(dir, nil, errors.Annotate(err, "LoadTree"))
}
for _, node := range tree.Nodes {
if err := res.restoreNodeTo(node, dir, dst); err != nil {
return err
}
if node.Type == "dir" {
if node.Subtree == nil {
return fmt.Errorf("Dir without subtree in tree %v", treeID.Str())
}
subp := filepath.Join(dir, node.Name)
err = res.restoreTo(dst, subp, node.Subtree)
if err != nil {
err = res.Error(subp, node, errors.Annotate(err, "restore subtree"))
if err != nil {
return err
}
}
// Restore directory timestamp at the end. If we would do it earlier, restoring files within
// the directory would overwrite the timestamp of the directory they are in.
if err := node.RestoreTimestamps(filepath.Join(dst, dir, node.Name)); err != nil {
return err
}
}
}
return nil
}
func (res *Restorer) restoreNodeTo(node *Node, dir string, dst string) error {
dstPath := filepath.Join(dst, dir, node.Name)
if res.Filter != nil && res.Filter(filepath.Join(dir, node.Name), dstPath, node) {
return nil
}
err := node.CreateAt(dstPath, res.repo)
// Did it fail because of ENOENT?
if pe, ok := errors.Cause(err).(*os.PathError); ok {
errn, ok := pe.Err.(syscall.Errno)
if ok && errn == syscall.ENOENT {
// Create parent directories and retry
err = os.MkdirAll(filepath.Dir(dstPath), 0700)
if err == nil || err == os.ErrExist {
err = node.CreateAt(dstPath, res.repo)
}
}
}
if err != nil {
err = res.Error(dstPath, node, errors.Annotate(err, "create node"))
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 {
return res.restoreTo(dir, "", res.sn.Tree)
}
// Snapshot returns the snapshot this restorer is configured to use.
func (res *Restorer) Snapshot() *Snapshot {
return res.sn
}