mirror of
https://github.com/restic/restic.git
synced 2024-08-23 12:50:45 +02:00
381 lines
7.8 KiB
Go
381 lines
7.8 KiB
Go
package local
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/hex"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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"sort"
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"strings"
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"github.com/restic/restic/backend"
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)
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var ErrWrongData = errors.New("wrong data returned by backend, checksum does not match")
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type Local struct {
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p string
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ver uint
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id string
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}
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// Open opens the local backend at dir.
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func Open(dir string) (*Local, error) {
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items := []string{
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dir,
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filepath.Join(dir, backend.Paths.Data),
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filepath.Join(dir, backend.Paths.Snapshots),
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filepath.Join(dir, backend.Paths.Trees),
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filepath.Join(dir, backend.Paths.Index),
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filepath.Join(dir, backend.Paths.Locks),
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filepath.Join(dir, backend.Paths.Keys),
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filepath.Join(dir, backend.Paths.Temp),
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}
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// test if all necessary dirs and files are there
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for _, d := range items {
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if _, err := os.Stat(d); err != nil {
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return nil, fmt.Errorf("%s does not exist", d)
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}
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}
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// read version file
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f, err := os.Open(filepath.Join(dir, backend.Paths.Version))
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if err != nil {
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return nil, fmt.Errorf("unable to read version file: %v\n", err)
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}
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var version uint
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n, err := fmt.Fscanf(f, "%d", &version)
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if err != nil {
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return nil, err
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}
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if n != 1 {
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return nil, errors.New("could not read version from file")
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}
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err = f.Close()
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if err != nil {
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return nil, err
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}
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// check version
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if version != backend.Version {
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return nil, fmt.Errorf("wrong version %d", version)
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}
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// read ID
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f, err = os.Open(filepath.Join(dir, backend.Paths.ID))
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if err != nil {
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return nil, err
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}
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buf, err := ioutil.ReadAll(f)
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if err != nil {
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return nil, err
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}
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err = f.Close()
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if err != nil {
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return nil, err
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}
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id := strings.TrimSpace(string(buf))
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if err != nil {
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return nil, err
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}
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return &Local{p: dir, ver: version, id: id}, nil
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}
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// Create creates all the necessary files and directories for a new local
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// backend at dir.
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func Create(dir string) (*Local, error) {
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versionFile := filepath.Join(dir, backend.Paths.Version)
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idFile := filepath.Join(dir, backend.Paths.ID)
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dirs := []string{
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dir,
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filepath.Join(dir, backend.Paths.Data),
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filepath.Join(dir, backend.Paths.Snapshots),
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filepath.Join(dir, backend.Paths.Trees),
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filepath.Join(dir, backend.Paths.Index),
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filepath.Join(dir, backend.Paths.Locks),
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filepath.Join(dir, backend.Paths.Keys),
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filepath.Join(dir, backend.Paths.Temp),
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}
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// test if files already exist
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_, err := os.Lstat(versionFile)
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if err == nil {
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return nil, errors.New("version file already exists")
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}
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_, err = os.Lstat(idFile)
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if err == nil {
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return nil, errors.New("id file already exists")
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}
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// test if directories already exist
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for _, d := range dirs[1:] {
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if _, err := os.Stat(d); err == nil {
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return nil, fmt.Errorf("dir %s already exists", d)
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}
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}
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// create paths for data, refs and temp
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for _, d := range dirs {
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err := os.MkdirAll(d, backend.Modes.Dir)
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if err != nil {
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return nil, err
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}
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}
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// create version file
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f, err := os.Create(versionFile)
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if err != nil {
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return nil, err
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}
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_, err = fmt.Fprintf(f, "%d\n", backend.Version)
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if err != nil {
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return nil, err
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}
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err = f.Close()
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if err != nil {
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return nil, err
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}
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// create ID file
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id := make([]byte, sha256.Size)
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_, err = rand.Read(id)
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if err != nil {
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return nil, err
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}
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f, err = os.Create(idFile)
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if err != nil {
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return nil, err
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}
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_, err = fmt.Fprintln(f, hex.EncodeToString(id))
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if err != nil {
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return nil, err
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}
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err = f.Close()
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if err != nil {
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return nil, err
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}
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// open backend
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return Open(dir)
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}
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// Location returns this backend's location (the directory name).
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func (b *Local) Location() string {
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return b.p
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}
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// Return temp directory in correct directory for this backend.
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func (b *Local) tempFile() (*os.File, error) {
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return ioutil.TempFile(filepath.Join(b.p, backend.Paths.Temp), "temp-")
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}
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type localBlob struct {
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f *os.File
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size uint
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final bool
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basedir string
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}
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func (lb *localBlob) Write(p []byte) (int, error) {
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if lb.final {
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return 0, errors.New("blob already closed")
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}
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n, err := lb.f.Write(p)
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lb.size += uint(n)
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return n, err
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}
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func (lb *localBlob) Size() uint {
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return lb.size
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}
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func (lb *localBlob) Finalize(t backend.Type, name string) error {
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if lb.final {
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return errors.New("Already finalized")
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}
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lb.final = true
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err := lb.f.Close()
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if err != nil {
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return fmt.Errorf("local: file.Close: %v", err)
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}
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f := filename(lb.basedir, t, name)
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// create directories if necessary, ignore errors
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if t == backend.Data || t == backend.Tree {
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os.MkdirAll(filepath.Dir(f), backend.Modes.Dir)
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}
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// test if new path already exists
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if _, err := os.Stat(f); err == nil {
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return fmt.Errorf("Close(): file %v already exists", f)
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}
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if err := os.Rename(lb.f.Name(), f); err != nil {
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return err
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}
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// set mode to read-only
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fi, err := os.Stat(f)
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if err != nil {
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return err
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}
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return os.Chmod(f, fi.Mode()&os.FileMode(^uint32(0222)))
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}
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// Create creates a new Blob. The data is available only after Finalize()
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// has been called on the returned Blob.
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func (b *Local) Create() (backend.Blob, error) {
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// TODO: make sure that tempfile is removed upon error
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// create tempfile in backend
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file, err := b.tempFile()
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if err != nil {
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return nil, err
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}
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blob := localBlob{
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f: file,
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basedir: b.p,
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}
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return &blob, nil
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}
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// Construct path for given Type and name.
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func filename(base string, t backend.Type, name string) string {
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return filepath.Join(dirname(base, t, name), name)
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}
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// Construct directory for given Type.
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func dirname(base string, t backend.Type, name string) string {
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var n string
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switch t {
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case backend.Data:
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n = backend.Paths.Data
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if len(name) > 2 {
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n = filepath.Join(n, name[:2])
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}
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case backend.Snapshot:
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n = backend.Paths.Snapshots
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case backend.Tree:
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n = backend.Paths.Trees
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if len(name) > 2 {
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n = filepath.Join(n, name[:2])
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}
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case backend.Index:
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n = backend.Paths.Index
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case backend.Lock:
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n = backend.Paths.Locks
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case backend.Key:
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n = backend.Paths.Keys
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}
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return filepath.Join(base, n)
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}
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// Get returns a reader that yields the content stored under the given
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// name. The reader should be closed after draining it.
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func (b *Local) Get(t backend.Type, name string) (io.ReadCloser, error) {
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return os.Open(filename(b.p, t, name))
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}
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// Test returns true if a blob of the given type and name exists in the backend.
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func (b *Local) Test(t backend.Type, name string) (bool, error) {
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_, err := os.Stat(filename(b.p, t, name))
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if err != nil {
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if os.IsNotExist(err) {
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return false, nil
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}
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return false, err
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}
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return true, nil
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}
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// Remove removes the blob with the given name and type.
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func (b *Local) Remove(t backend.Type, name string) error {
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return os.Remove(filename(b.p, t, name))
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}
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// List returns a channel that yields all names of blobs of type t. A
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// goroutine ist started for this. If the channel done is closed, sending
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// stops.
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func (b *Local) List(t backend.Type, done <-chan struct{}) <-chan string {
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// TODO: use os.Open() and d.Readdirnames() instead of Glob()
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var pattern string
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if t == backend.Data || t == backend.Tree {
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pattern = filepath.Join(dirname(b.p, t, ""), "*", "*")
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} else {
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pattern = filepath.Join(dirname(b.p, t, ""), "*")
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}
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ch := make(chan string)
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matches, err := filepath.Glob(pattern)
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if err != nil {
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close(ch)
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return ch
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}
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for i := range matches {
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matches[i] = filepath.Base(matches[i])
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}
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sort.Strings(matches)
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go func() {
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defer close(ch)
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for _, m := range matches {
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if m == "" {
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continue
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}
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select {
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case ch <- m:
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case <-done:
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return
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}
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}
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}()
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return ch
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}
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// Version returns the version of this local backend.
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func (b *Local) Version() uint {
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return b.ver
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}
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// ID returns the ID of this local backend.
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func (b *Local) ID() string {
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return b.id
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}
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// Delete removes the repository and all files.
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func (b *Local) Delete() error { return os.RemoveAll(b.p) }
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// Close does nothing
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func (b *Local) Close() error { return nil }
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