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Refactor: introduced restorer tree visitor

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Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
This commit is contained in:
Igor Fedorenko
2018-04-07 22:43:14 -04:00
parent 26be094f28
commit 5fa6dc53cb
4 changed files with 89 additions and 42 deletions
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110
internal/restorer/restorer.go
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@@ -2,7 +2,6 @@ package restorer
import (
"context"
"os"
"path/filepath"
"github.com/restic/restic/internal/errors"
@@ -40,9 +39,15 @@ func NewRestorer(repo restic.Repository, id restic.ID) (*Restorer, error) {
return r, nil
}
// restoreTo restores a tree from the repo to a destination. target is the path in
// the file system, location within the snapshot.
func (res *Restorer) restoreTo(ctx context.Context, target, location string, treeID restic.ID, idx *restic.HardlinkIndex) error {
type treeVisitor struct {
enterDir func(node *restic.Node, target, location string) error
visitNode func(node *restic.Node, target, location string) error
leaveDir func(node *restic.Node, target, location string) error
}
// traverseTree traverses a tree from the repo and calls treeVisitor.
// target is the path in the file system, location within the snapshot.
func (res *Restorer) traverseTree(ctx context.Context, target, location string, treeID restic.ID, visitor treeVisitor) error {
debug.Log("%v %v %v", target, location, treeID)
tree, err := res.repo.LoadTree(ctx, treeID)
if err != nil {
@@ -85,32 +90,65 @@ func (res *Restorer) restoreTo(ctx context.Context, target, location string, tre
selectedForRestore, childMayBeSelected := res.SelectFilter(nodeLocation, nodeTarget, node)
debug.Log("SelectFilter returned %v %v", selectedForRestore, childMayBeSelected)
if node.Type == "dir" && childMayBeSelected {
sanitizeError := func(err error) error {
if err != nil {
err = res.Error(nodeTarget, node, err)
}
return err
}
enteredDir := false
if node.Type == "dir" {
if node.Subtree == nil {
return errors.Errorf("Dir without subtree in tree %v", treeID.Str())
}
err = res.restoreTo(ctx, nodeTarget, nodeLocation, *node.Subtree, idx)
if err != nil {
err = res.Error(nodeLocation, node, err)
// ifedorenko: apparently a dir can be selected explicitly or implicitly when a child is selected
// to support implicit selection, visit the directory from within visitor#visitNode
if selectedForRestore {
enteredDir = true
err = sanitizeError(visitor.enterDir(node, nodeTarget, nodeLocation))
if err != nil {
return err
}
} else {
_visitor := visitor
visitor = treeVisitor{
enterDir: _visitor.enterDir,
visitNode: func(node *restic.Node, nodeTarget, nodeLocation string) error {
if !enteredDir {
enteredDir = true
derr := sanitizeError(_visitor.enterDir(node, nodeTarget, nodeLocation))
if derr != nil {
return derr
}
}
return _visitor.visitNode(node, nodeTarget, nodeLocation)
},
leaveDir: _visitor.leaveDir,
}
}
if childMayBeSelected {
err = sanitizeError(res.traverseTree(ctx, nodeTarget, nodeLocation, *node.Subtree, visitor))
if err != nil {
return err
}
}
}
if selectedForRestore {
err = res.restoreNodeTo(ctx, node, nodeTarget, nodeLocation, idx)
if selectedForRestore && node.Type != "dir" {
err = sanitizeError(visitor.visitNode(node, nodeTarget, nodeLocation))
if err != nil {
err = res.Error(nodeLocation, node, errors.Wrap(err, "restoreNodeTo"))
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.
err = node.RestoreTimestamps(nodeTarget)
if enteredDir {
err = sanitizeError(visitor.leaveDir(node, nodeTarget, nodeLocation))
if err != nil {
err = res.Error(nodeLocation, node, errors.Wrap(err, "RestoreTimestamps"))
if err != nil {
@@ -124,33 +162,26 @@ func (res *Restorer) restoreTo(ctx context.Context, target, location string, tre
}
func (res *Restorer) restoreNodeTo(ctx context.Context, node *restic.Node, target, location string, idx *restic.HardlinkIndex) error {
debug.Log("%v %v %v", node.Name, target, location)
debug.Log("restoreNode %v %v %v", node.Name, target, location)
err := node.CreateAt(ctx, target, res.repo, idx)
if err != nil {
debug.Log("node.CreateAt(%s) error %v", target, err)
}
// Did it fail because of ENOENT?
if err != nil && os.IsNotExist(errors.Cause(err)) {
debug.Log("create intermediate paths")
// Create parent directories and retry
err = fs.MkdirAll(filepath.Dir(target), 0700)
if err == nil || os.IsExist(errors.Cause(err)) {
err = node.CreateAt(ctx, target, res.repo, idx)
}
if err == nil {
err = res.restoreNodeMetadataTo(node, target, location)
}
return err
}
func (res *Restorer) restoreNodeMetadataTo(node *restic.Node, target, location string) error {
debug.Log("restoreNodeMetadata %v %v %v", node.Name, target, location)
err := node.RestoreMetadata(target)
if err != nil {
debug.Log("error %v", err)
err = res.Error(location, node, err)
if err != nil {
return err
}
debug.Log("node.RestoreMetadata(%s) error %v", target, err)
}
return nil
return err
}
// RestoreTo creates the directories and files in the snapshot below dst.
@@ -165,7 +196,22 @@ func (res *Restorer) RestoreTo(ctx context.Context, dst string) error {
}
idx := restic.NewHardlinkIndex()
return res.restoreTo(ctx, dst, string(filepath.Separator), *res.sn.Tree, idx)
return res.traverseTree(ctx, dst, string(filepath.Separator), *res.sn.Tree, treeVisitor{
enterDir: func(node *restic.Node, target, location string) error {
// create dir with default permissions
// #leaveDir restores dir metadata after visiting all children
return fs.MkdirAll(target, 0700)
},
visitNode: func(node *restic.Node, target, location string) error {
return res.restoreNodeTo(ctx, node, target, location, idx)
},
leaveDir: func(node *restic.Node, target, location string) error {
// Restore directory permissions and timestamp at the end. If we did it earlier
// - children restore could fail because of restictive directory permission
// - children restore could overwrite the timestamp of the directory they are in
return res.restoreNodeMetadataTo(node, target, location)
},
})
}
// Snapshot returns the snapshot this restorer is configured to use.