/
tree.go
217 lines (179 loc) · 4.88 KB
/
tree.go
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package restic
import (
"bytes"
"context"
"encoding/json"
"fmt"
"path"
"sort"
"strings"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/debug"
)
// Tree is an ordered list of nodes.
type Tree struct {
Nodes []*Node `json:"nodes"`
}
// NewTree creates a new tree object with the given initial capacity.
func NewTree(capacity int) *Tree {
return &Tree{
Nodes: make([]*Node, 0, capacity),
}
}
func (t *Tree) String() string {
return fmt.Sprintf("Tree<%d nodes>", len(t.Nodes))
}
// Equals returns true if t and other have exactly the same nodes.
func (t *Tree) Equals(other *Tree) bool {
if len(t.Nodes) != len(other.Nodes) {
debug.Log("tree.Equals(): trees have different number of nodes")
return false
}
for i := 0; i < len(t.Nodes); i++ {
if !t.Nodes[i].Equals(*other.Nodes[i]) {
debug.Log("tree.Equals(): node %d is different:", i)
debug.Log(" %#v", t.Nodes[i])
debug.Log(" %#v", other.Nodes[i])
return false
}
}
return true
}
// Insert adds a new node at the correct place in the tree.
func (t *Tree) Insert(node *Node) error {
pos, found := t.find(node.Name)
if found != nil {
return errors.Errorf("node %q already present", node.Name)
}
// https://github.com/golang/go/wiki/SliceTricks
t.Nodes = append(t.Nodes, nil)
copy(t.Nodes[pos+1:], t.Nodes[pos:])
t.Nodes[pos] = node
return nil
}
func (t *Tree) find(name string) (int, *Node) {
pos := sort.Search(len(t.Nodes), func(i int) bool {
return t.Nodes[i].Name >= name
})
if pos < len(t.Nodes) && t.Nodes[pos].Name == name {
return pos, t.Nodes[pos]
}
return pos, nil
}
// Find returns a node with the given name, or nil if none could be found.
func (t *Tree) Find(name string) *Node {
if t == nil {
return nil
}
_, node := t.find(name)
return node
}
// Sort sorts the nodes by name.
func (t *Tree) Sort() {
list := Nodes(t.Nodes)
sort.Sort(list)
t.Nodes = list
}
// Subtrees returns a slice of all subtree IDs of the tree.
func (t *Tree) Subtrees() (trees IDs) {
for _, node := range t.Nodes {
if node.Type == "dir" && node.Subtree != nil {
trees = append(trees, *node.Subtree)
}
}
return trees
}
type BlobLoader interface {
LoadBlob(context.Context, BlobType, ID, []byte) ([]byte, error)
}
// LoadTree loads a tree from the repository.
func LoadTree(ctx context.Context, r BlobLoader, id ID) (*Tree, error) {
debug.Log("load tree %v", id)
buf, err := r.LoadBlob(ctx, TreeBlob, id, nil)
if err != nil {
return nil, err
}
t := &Tree{}
err = json.Unmarshal(buf, t)
if err != nil {
return nil, err
}
return t, nil
}
type BlobSaver interface {
SaveBlob(context.Context, BlobType, []byte, ID, bool) (ID, bool, int, error)
}
// SaveTree stores a tree into the repository and returns the ID. The ID is
// checked against the index. The tree is only stored when the index does not
// contain the ID.
func SaveTree(ctx context.Context, r BlobSaver, t *Tree) (ID, error) {
buf, err := json.Marshal(t)
if err != nil {
return ID{}, errors.Wrap(err, "MarshalJSON")
}
// append a newline so that the data is always consistent (json.Encoder
// adds a newline after each object)
buf = append(buf, '\n')
id, _, _, err := r.SaveBlob(ctx, TreeBlob, buf, ID{}, false)
return id, err
}
var ErrTreeNotOrdered = errors.New("nodes are not ordered or duplicate")
type TreeJSONBuilder struct {
buf bytes.Buffer
lastName string
}
func NewTreeJSONBuilder() *TreeJSONBuilder {
tb := &TreeJSONBuilder{}
_, _ = tb.buf.WriteString(`{"nodes":[`)
return tb
}
func (builder *TreeJSONBuilder) AddNode(node *Node) error {
if node.Name <= builder.lastName {
return fmt.Errorf("node %q, last%q: %w", node.Name, builder.lastName, ErrTreeNotOrdered)
}
if builder.lastName != "" {
_ = builder.buf.WriteByte(',')
}
builder.lastName = node.Name
val, err := json.Marshal(node)
if err != nil {
return err
}
_, _ = builder.buf.Write(val)
return nil
}
func (builder *TreeJSONBuilder) Finalize() ([]byte, error) {
// append a newline so that the data is always consistent (json.Encoder
// adds a newline after each object)
_, _ = builder.buf.WriteString("]}\n")
buf := builder.buf.Bytes()
// drop reference to buffer
builder.buf = bytes.Buffer{}
return buf, nil
}
func FindTreeDirectory(ctx context.Context, repo BlobLoader, id *ID, dir string) (*ID, error) {
if id == nil {
return nil, errors.New("tree id is null")
}
dirs := strings.Split(path.Clean(dir), "/")
subfolder := ""
for _, name := range dirs {
if name == "" || name == "." {
continue
}
subfolder = path.Join(subfolder, name)
tree, err := LoadTree(ctx, repo, *id)
if err != nil {
return nil, fmt.Errorf("path %s: %w", subfolder, err)
}
node := tree.Find(name)
if node == nil {
return nil, fmt.Errorf("path %s: not found", subfolder)
}
if node.Type != "dir" || node.Subtree == nil {
return nil, fmt.Errorf("path %s: not a directory", subfolder)
}
id = node.Subtree
}
return id, nil
}