package storage import ( "context" "errors" "io" "path" "strings" "github.com/docker/distribution/registry/storage/driver" ) // errFinishedWalk signals an early exit to the walk when the current query // is satisfied. var errFinishedWalk = errors.New("finished walk") // Returns a list, or partial list, of repositories in the registry. // Because it's a quite expensive operation, it should only be used when building up // an initial set of repositories. func (reg *registry) Repositories(ctx context.Context, repos []string, last string) (n int, err error) { var foundRepos []string if len(repos) == 0 { return 0, errors.New("no space in slice") } root, err := pathFor(repositoriesRootPathSpec{}) if err != nil { return 0, err } err = Walk(ctx, reg.blobStore.driver, root, func(fileInfo driver.FileInfo) error { err := handleRepository(fileInfo, root, last, func(repoPath string) error { foundRepos = append(foundRepos, repoPath) return nil }) if err != nil { return err } // if we've filled our array, no need to walk any further if len(foundRepos) == len(repos) { return errFinishedWalk } return nil }) n = copy(repos, foundRepos) switch err { case nil: // nil means that we completed walk and didn't fill buffer. No more // records are available. err = io.EOF case errFinishedWalk: // more records are available. err = nil } return n, err } // Enumerate applies ingester to each repository func (reg *registry) Enumerate(ctx context.Context, ingester func(string) error) error { root, err := pathFor(repositoriesRootPathSpec{}) if err != nil { return err } err = Walk(ctx, reg.blobStore.driver, root, func(fileInfo driver.FileInfo) error { return handleRepository(fileInfo, root, "", ingester) }) return err } // lessPath returns true if one path a is less than path b. // // A component-wise comparison is done, rather than the lexical comparison of // strings. func lessPath(a, b string) bool { // we provide this behavior by making separator always sort first. return compareReplaceInline(a, b, '/', '\x00') < 0 } // compareReplaceInline modifies runtime.cmpstring to replace old with new // during a byte-wise comparison. func compareReplaceInline(s1, s2 string, old, new byte) int { // TODO(stevvooe): We are missing an optimization when the s1 and s2 have // the exact same slice header. It will make the code unsafe but can // provide some extra performance. l := len(s1) if len(s2) < l { l = len(s2) } for i := 0; i < l; i++ { c1, c2 := s1[i], s2[i] if c1 == old { c1 = new } if c2 == old { c2 = new } if c1 < c2 { return -1 } if c1 > c2 { return +1 } } if len(s1) < len(s2) { return -1 } if len(s1) > len(s2) { return +1 } return 0 } // handleRepository calls function fn with a repository path if fileInfo // has a path of a repository under root and that it is lexographically // after last. Otherwise, it will return ErrSkipDir. This should be used // with Walk to do handling with repositories in a storage. func handleRepository(fileInfo driver.FileInfo, root, last string, fn func(repoPath string) error) error { filePath := fileInfo.Path() // lop the base path off repo := filePath[len(root)+1:] _, file := path.Split(repo) if file == "_layers" { repo = strings.TrimSuffix(repo, "/_layers") if lessPath(last, repo) { if err := fn(repo); err != nil { return err } } return driver.ErrSkipDir } else if strings.HasPrefix(file, "_") { return driver.ErrSkipDir } return nil }