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mirror of https://github.com/octoleo/restic.git synced 2024-10-31 19:02:32 +00:00

Add walker for trees in the repo

This commit is contained in:
Alexander Neumann 2018-06-09 18:19:27 +02:00
parent 14aead94b3
commit 3a86f4852b
3 changed files with 558 additions and 0 deletions

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package walker

134
internal/walker/walker.go Normal file
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package walker
import (
"context"
"path"
"sort"
"github.com/pkg/errors"
"github.com/restic/restic/internal/restic"
)
// TreeLoader loads a tree from a repository.
type TreeLoader interface {
LoadTree(context.Context, restic.ID) (*restic.Tree, error)
}
// SkipNode is returned by WalkFunc when a dir node should not be walked.
var SkipNode = errors.New("skip this node")
// WalkFunc is the type of the function called for each node visited by Walk.
// Path is the slash-separated path from the root node. If there was a problem
// loading a node, err is set to a non-nil error. WalkFunc can chose to ignore
// it by returning nil.
//
// When the special value SkipNode is returned and node is a dir node, it is
// not walked. When the node is not a dir node, the remaining items in this
// tree are skipped.
//
// Setting ignore to true tells Walk that it should not visit the node again.
// For tree nodes, this means that the function is not called for the
// referenced tree. If the node is not a tree, and all nodes in the current
// tree have ignore set to true, the current tree will not be visited again.
// When err is not nil and different from SkipNode, the value returned for
// ignore is ignored.
type WalkFunc func(path string, node *restic.Node, nodeErr error) (ignore bool, err error)
// Walk calls walkFn recursively for each node in root. If walkFn returns an
// error, it is passed up the call stack. The trees in ignoreTrees are not
// walked. If walkFn ignores trees, these are added to the set.
func Walk(ctx context.Context, repo TreeLoader, root restic.ID, ignoreTrees restic.IDSet, walkFn WalkFunc) error {
tree, err := repo.LoadTree(ctx, root)
_, err = walkFn("/", nil, err)
if err != nil {
if err == SkipNode {
err = nil
}
return err
}
_, err = walk(ctx, repo, "/", tree, ignoreTrees, walkFn)
return err
}
// walk recursively traverses the tree, ignoring subtrees when the ID of the
// subtree is in ignoreTrees. If err is nil and ignore is true, the subtree ID
// will be added to ignoreTrees by walk.
func walk(ctx context.Context, repo TreeLoader, prefix string, tree *restic.Tree, ignoreTrees restic.IDSet, walkFn WalkFunc) (ignore bool, err error) {
var allNodesIgnored = true
sort.Slice(tree.Nodes, func(i, j int) bool {
return tree.Nodes[i].Name < tree.Nodes[j].Name
})
for _, node := range tree.Nodes {
p := path.Join(prefix, node.Name)
if node.Type == "" {
return false, errors.Errorf("node type is empty for node %q", node.Name)
}
if node.Type != "dir" {
ignore, err := walkFn(p, node, nil)
if err != nil {
if err == SkipNode {
// skip the remaining entries in this tree
return allNodesIgnored, nil
}
return false, err
}
if ignore == false {
allNodesIgnored = false
}
continue
}
if node.Subtree == nil {
return false, errors.Errorf("subtree for node %v in tree %v is nil", node.Name, p)
}
if ignoreTrees.Has(*node.Subtree) {
continue
}
subtree, err := repo.LoadTree(ctx, *node.Subtree)
ignore, err := walkFn(p, node, err)
if err != nil {
if err == SkipNode {
if ignore {
ignoreTrees.Insert(*node.Subtree)
}
continue
}
return false, err
}
if ignore {
ignoreTrees.Insert(*node.Subtree)
}
if !ignore {
allNodesIgnored = false
}
ignore, err = walk(ctx, repo, p, subtree, ignoreTrees, walkFn)
if err != nil {
return false, err
}
if ignore {
ignoreTrees.Insert(*node.Subtree)
}
if !ignore {
allNodesIgnored = false
}
}
return allNodesIgnored, nil
}

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package walker
import (
"context"
"encoding/json"
"fmt"
"testing"
"github.com/pkg/errors"
"github.com/restic/restic/internal/restic"
)
// TestTree is used to construct a list of trees for testing the walker.
type TestTree map[string]interface{}
// TestNode is used to test the walker.
type TestFile struct{}
func BuildTreeMap(tree TestTree) (m TreeMap, root restic.ID) {
m = TreeMap{}
id := buildTreeMap(tree, m)
return m, id
}
func buildTreeMap(tree TestTree, m TreeMap) restic.ID {
res := restic.NewTree()
for name, item := range tree {
switch elem := item.(type) {
case TestFile:
res.Insert(&restic.Node{
Name: name,
Type: "file",
})
case TestTree:
id := buildTreeMap(elem, m)
res.Insert(&restic.Node{
Name: name,
Subtree: &id,
Type: "dir",
})
default:
panic(fmt.Sprintf("invalid type %T", elem))
}
}
buf, err := json.Marshal(res)
if err != nil {
panic(err)
}
id := restic.Hash(buf)
if _, ok := m[id]; !ok {
m[id] = res
}
return id
}
// TreeMap returns the trees from the map on LoadTree.
type TreeMap map[restic.ID]*restic.Tree
func (t TreeMap) LoadTree(ctx context.Context, id restic.ID) (*restic.Tree, error) {
tree, ok := t[id]
if !ok {
return nil, errors.New("tree not found")
}
return tree, nil
}
// checkFunc returns a function suitable for walking the tree to check
// something, and a function which will check the final result.
type checkFunc func(t testing.TB) (walker WalkFunc, final func(testing.TB))
// checkItemOrder ensures that the order of the 'path' arguments is the one passed in as 'want'.
func checkItemOrder(want []string) checkFunc {
pos := 0
return func(t testing.TB) (walker WalkFunc, final func(testing.TB)) {
walker = func(path string, node *restic.Node, err error) (bool, error) {
if err != nil {
t.Errorf("error walking %v: %v", path, err)
return false, err
}
if pos >= len(want) {
t.Errorf("additional unexpected path found: %v", path)
return false, nil
}
if path != want[pos] {
t.Errorf("wrong path found, want %q, got %q", want[pos], path)
}
pos++
return false, nil
}
final = func(t testing.TB) {
if pos != len(want) {
t.Errorf("not enough items returned, want %d, got %d", len(want), pos)
}
}
return walker, final
}
}
// checkSkipFor returns SkipNode if path is in skipFor, it checks that the
// paths the walk func is called for are exactly the ones in wantPaths.
func checkSkipFor(skipFor map[string]struct{}, wantPaths []string) checkFunc {
var pos int
return func(t testing.TB) (walker WalkFunc, final func(testing.TB)) {
walker = func(path string, node *restic.Node, err error) (bool, error) {
if err != nil {
t.Errorf("error walking %v: %v", path, err)
return false, err
}
if pos >= len(wantPaths) {
t.Errorf("additional unexpected path found: %v", path)
return false, nil
}
if path != wantPaths[pos] {
t.Errorf("wrong path found, want %q, got %q", wantPaths[pos], path)
}
pos++
if _, ok := skipFor[path]; ok {
return false, SkipNode
}
return false, nil
}
final = func(t testing.TB) {
if pos != len(wantPaths) {
t.Errorf("wrong number of paths returned, want %d, got %d", len(wantPaths), pos)
}
}
return walker, final
}
}
// checkIgnore returns SkipNode if path is in skipFor and sets ignore according
// to ignoreFor. It checks that the paths the walk func is called for are exactly
// the ones in wantPaths.
func checkIgnore(skipFor map[string]struct{}, ignoreFor map[string]bool, wantPaths []string) checkFunc {
var pos int
return func(t testing.TB) (walker WalkFunc, final func(testing.TB)) {
walker = func(path string, node *restic.Node, err error) (bool, error) {
if err != nil {
t.Errorf("error walking %v: %v", path, err)
return false, err
}
if pos >= len(wantPaths) {
t.Errorf("additional unexpected path found: %v", path)
return ignoreFor[path], nil
}
if path != wantPaths[pos] {
t.Errorf("wrong path found, want %q, got %q", wantPaths[pos], path)
}
pos++
if _, ok := skipFor[path]; ok {
return ignoreFor[path], SkipNode
}
return ignoreFor[path], nil
}
final = func(t testing.TB) {
if pos != len(wantPaths) {
t.Errorf("wrong number of paths returned, want %d, got %d", len(wantPaths), pos)
}
}
return walker, final
}
}
func TestWalker(t *testing.T) {
var tests = []struct {
tree TestTree
checks []checkFunc
}{
{
tree: TestTree{
"foo": TestFile{},
"subdir": TestTree{
"subfile": TestFile{},
},
},
checks: []checkFunc{
checkItemOrder([]string{
"/",
"/foo",
"/subdir",
"/subdir/subfile",
}),
checkSkipFor(
map[string]struct{}{
"/subdir": struct{}{},
}, []string{
"/",
"/foo",
"/subdir",
},
),
checkIgnore(
map[string]struct{}{}, map[string]bool{
"/subdir": true,
}, []string{
"/",
"/foo",
"/subdir",
"/subdir/subfile",
},
),
},
},
{
tree: TestTree{
"foo": TestFile{},
"subdir1": TestTree{
"subfile1": TestFile{},
},
"subdir2": TestTree{
"subfile2": TestFile{},
"subsubdir2": TestTree{
"subsubfile3": TestFile{},
},
},
},
checks: []checkFunc{
checkItemOrder([]string{
"/",
"/foo",
"/subdir1",
"/subdir1/subfile1",
"/subdir2",
"/subdir2/subfile2",
"/subdir2/subsubdir2",
"/subdir2/subsubdir2/subsubfile3",
}),
checkSkipFor(
map[string]struct{}{
"/subdir1": struct{}{},
}, []string{
"/",
"/foo",
"/subdir1",
"/subdir2",
"/subdir2/subfile2",
"/subdir2/subsubdir2",
"/subdir2/subsubdir2/subsubfile3",
},
),
checkSkipFor(
map[string]struct{}{
"/subdir1": struct{}{},
"/subdir2/subsubdir2": struct{}{},
}, []string{
"/",
"/foo",
"/subdir1",
"/subdir2",
"/subdir2/subfile2",
"/subdir2/subsubdir2",
},
),
checkSkipFor(
map[string]struct{}{
"/foo": struct{}{},
}, []string{
"/",
"/foo",
},
),
},
},
{
tree: TestTree{
"foo": TestFile{},
"subdir1": TestTree{
"subfile1": TestFile{},
"subfile2": TestFile{},
"subfile3": TestFile{},
},
"subdir2": TestTree{
"subfile1": TestFile{},
"subfile2": TestFile{},
"subfile3": TestFile{},
},
"subdir3": TestTree{
"subfile1": TestFile{},
"subfile2": TestFile{},
"subfile3": TestFile{},
},
"zzz other": TestFile{},
},
checks: []checkFunc{
checkItemOrder([]string{
"/",
"/foo",
"/subdir1",
"/subdir1/subfile1",
"/subdir1/subfile2",
"/subdir1/subfile3",
"/subdir2",
"/subdir2/subfile1",
"/subdir2/subfile2",
"/subdir2/subfile3",
"/subdir3",
"/subdir3/subfile1",
"/subdir3/subfile2",
"/subdir3/subfile3",
"/zzz other",
}),
checkIgnore(
map[string]struct{}{
"/subdir1": struct{}{},
}, map[string]bool{
"/subdir1": true,
}, []string{
"/",
"/foo",
"/subdir1",
"/zzz other",
},
),
checkIgnore(
map[string]struct{}{}, map[string]bool{
"/subdir1": true,
}, []string{
"/",
"/foo",
"/subdir1",
"/subdir1/subfile1",
"/subdir1/subfile2",
"/subdir1/subfile3",
"/zzz other",
},
),
checkIgnore(
map[string]struct{}{
"/subdir2": struct{}{},
}, map[string]bool{
"/subdir2": true,
}, []string{
"/",
"/foo",
"/subdir1",
"/subdir1/subfile1",
"/subdir1/subfile2",
"/subdir1/subfile3",
"/subdir2",
"/zzz other",
},
),
checkIgnore(
map[string]struct{}{}, map[string]bool{
"/subdir1/subfile1": true,
"/subdir1/subfile2": true,
"/subdir1/subfile3": true,
}, []string{
"/",
"/foo",
"/subdir1",
"/subdir1/subfile1",
"/subdir1/subfile2",
"/subdir1/subfile3",
"/zzz other",
},
),
checkIgnore(
map[string]struct{}{}, map[string]bool{
"/subdir2/subfile1": true,
"/subdir2/subfile2": true,
"/subdir2/subfile3": true,
}, []string{
"/",
"/foo",
"/subdir1",
"/subdir1/subfile1",
"/subdir1/subfile2",
"/subdir1/subfile3",
"/subdir2",
"/subdir2/subfile1",
"/subdir2/subfile2",
"/subdir2/subfile3",
"/zzz other",
},
),
},
},
}
for _, test := range tests {
t.Run("", func(t *testing.T) {
repo, root := BuildTreeMap(test.tree)
for _, check := range test.checks {
t.Run("", func(t *testing.T) {
ctx, cancel := context.WithCancel(context.TODO())
defer cancel()
fn, last := check(t)
err := Walk(ctx, repo, root, restic.NewIDSet(), fn)
if err != nil {
t.Error(err)
}
last(t)
})
}
})
}
}