chore: vendor

vendor/github.com/docker/distribution/registry/client/repository.go

@@ -0,0 +1,870 @@
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/distribution/reference"
+	"github.com/docker/distribution"
+	v2 "github.com/docker/distribution/registry/api/v2"
+	"github.com/docker/distribution/registry/client/transport"
+	"github.com/docker/distribution/registry/storage/cache"
+	"github.com/docker/distribution/registry/storage/cache/memory"
+	"github.com/opencontainers/go-digest"
+)
+
+// Registry provides an interface for calling Repositories, which returns a catalog of repositories.
+type Registry interface {
+	Repositories(ctx context.Context, repos []string, last string) (n int, err error)
+}
+
+// checkHTTPRedirect is a callback that can manipulate redirected HTTP
+// requests. It is used to preserve Accept and Range headers.
+func checkHTTPRedirect(req *http.Request, via []*http.Request) error {
+	if len(via) >= 10 {
+		return errors.New("stopped after 10 redirects")
+	}
+
+	if len(via) > 0 {
+		for headerName, headerVals := range via[0].Header {
+			if headerName != "Accept" && headerName != "Range" {
+				continue
+			}
+			for _, val := range headerVals {
+				// Don't add to redirected request if redirected
+				// request already has a header with the same
+				// name and value.
+				hasValue := false
+				for _, existingVal := range req.Header[headerName] {
+					if existingVal == val {
+						hasValue = true
+						break
+					}
+				}
+				if !hasValue {
+					req.Header.Add(headerName, val)
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+// NewRegistry creates a registry namespace which can be used to get a listing of repositories
+func NewRegistry(baseURL string, transport http.RoundTripper) (Registry, error) {
+	ub, err := v2.NewURLBuilderFromString(baseURL, false)
+	if err != nil {
+		return nil, err
+	}
+
+	client := &http.Client{
+		Transport:     transport,
+		Timeout:       1 * time.Minute,
+		CheckRedirect: checkHTTPRedirect,
+	}
+
+	return &registry{
+		client: client,
+		ub:     ub,
+	}, nil
+}
+
+type registry struct {
+	client *http.Client
+	ub     *v2.URLBuilder
+}
+
+// Repositories returns a lexigraphically sorted catalog given a base URL.  The 'entries' slice will be filled up to the size
+// of the slice, starting at the value provided in 'last'.  The number of entries will be returned along with io.EOF if there
+// are no more entries
+func (r *registry) Repositories(ctx context.Context, entries []string, last string) (int, error) {
+	var numFilled int
+	var returnErr error
+
+	values := buildCatalogValues(len(entries), last)
+	u, err := r.ub.BuildCatalogURL(values)
+	if err != nil {
+		return 0, err
+	}
+
+	resp, err := r.client.Get(u)
+	if err != nil {
+		return 0, err
+	}
+	defer resp.Body.Close()
+
+	if SuccessStatus(resp.StatusCode) {
+		var ctlg struct {
+			Repositories []string `json:"repositories"`
+		}
+		decoder := json.NewDecoder(resp.Body)
+
+		if err := decoder.Decode(&ctlg); err != nil {
+			return 0, err
+		}
+
+		copy(entries, ctlg.Repositories)
+		numFilled = len(ctlg.Repositories)
+
+		link := resp.Header.Get("Link")
+		if link == "" {
+			returnErr = io.EOF
+		}
+	} else {
+		return 0, HandleErrorResponse(resp)
+	}
+
+	return numFilled, returnErr
+}
+
+// NewRepository creates a new Repository for the given repository name and base URL.
+func NewRepository(name reference.Named, baseURL string, transport http.RoundTripper) (distribution.Repository, error) {
+	ub, err := v2.NewURLBuilderFromString(baseURL, false)
+	if err != nil {
+		return nil, err
+	}
+
+	client := &http.Client{
+		Transport:     transport,
+		CheckRedirect: checkHTTPRedirect,
+		// TODO(dmcgowan): create cookie jar
+	}
+
+	return &repository{
+		client: client,
+		ub:     ub,
+		name:   name,
+	}, nil
+}
+
+type repository struct {
+	client *http.Client
+	ub     *v2.URLBuilder
+	name   reference.Named
+}
+
+func (r *repository) Named() reference.Named {
+	return r.name
+}
+
+func (r *repository) Blobs(ctx context.Context) distribution.BlobStore {
+	statter := &blobStatter{
+		name:   r.name,
+		ub:     r.ub,
+		client: r.client,
+	}
+	return &blobs{
+		name:    r.name,
+		ub:      r.ub,
+		client:  r.client,
+		statter: cache.NewCachedBlobStatter(memory.NewInMemoryBlobDescriptorCacheProvider(), statter),
+	}
+}
+
+func (r *repository) Manifests(ctx context.Context, options ...distribution.ManifestServiceOption) (distribution.ManifestService, error) {
+	// todo(richardscothern): options should be sent over the wire
+	return &manifests{
+		name:   r.name,
+		ub:     r.ub,
+		client: r.client,
+		etags:  make(map[string]string),
+	}, nil
+}
+
+func (r *repository) Tags(ctx context.Context) distribution.TagService {
+	return &tags{
+		client: r.client,
+		ub:     r.ub,
+		name:   r.Named(),
+	}
+}
+
+// tags implements remote tagging operations.
+type tags struct {
+	client *http.Client
+	ub     *v2.URLBuilder
+	name   reference.Named
+}
+
+// All returns all tags
+func (t *tags) All(ctx context.Context) ([]string, error) {
+	var tags []string
+
+	listURLStr, err := t.ub.BuildTagsURL(t.name)
+	if err != nil {
+		return tags, err
+	}
+
+	listURL, err := url.Parse(listURLStr)
+	if err != nil {
+		return tags, err
+	}
+
+	for {
+		resp, err := t.client.Get(listURL.String())
+		if err != nil {
+			return tags, err
+		}
+		defer resp.Body.Close()
+
+		if SuccessStatus(resp.StatusCode) {
+			b, err := ioutil.ReadAll(resp.Body)
+			if err != nil {
+				return tags, err
+			}
+
+			tagsResponse := struct {
+				Tags []string `json:"tags"`
+			}{}
+			if err := json.Unmarshal(b, &tagsResponse); err != nil {
+				return tags, err
+			}
+			tags = append(tags, tagsResponse.Tags...)
+			if link := resp.Header.Get("Link"); link != "" {
+				linkURLStr := strings.Trim(strings.Split(link, ";")[0], "<>")
+				linkURL, err := url.Parse(linkURLStr)
+				if err != nil {
+					return tags, err
+				}
+
+				listURL = listURL.ResolveReference(linkURL)
+			} else {
+				return tags, nil
+			}
+		} else {
+			return tags, HandleErrorResponse(resp)
+		}
+	}
+}
+
+func descriptorFromResponse(response *http.Response) (distribution.Descriptor, error) {
+	desc := distribution.Descriptor{}
+	headers := response.Header
+
+	ctHeader := headers.Get("Content-Type")
+	if ctHeader == "" {
+		return distribution.Descriptor{}, errors.New("missing or empty Content-Type header")
+	}
+	desc.MediaType = ctHeader
+
+	digestHeader := headers.Get("Docker-Content-Digest")
+	if digestHeader == "" {
+		bytes, err := ioutil.ReadAll(response.Body)
+		if err != nil {
+			return distribution.Descriptor{}, err
+		}
+		_, desc, err := distribution.UnmarshalManifest(ctHeader, bytes)
+		if err != nil {
+			return distribution.Descriptor{}, err
+		}
+		return desc, nil
+	}
+
+	dgst, err := digest.Parse(digestHeader)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	desc.Digest = dgst
+
+	lengthHeader := headers.Get("Content-Length")
+	if lengthHeader == "" {
+		return distribution.Descriptor{}, errors.New("missing or empty Content-Length header")
+	}
+	length, err := strconv.ParseInt(lengthHeader, 10, 64)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	desc.Size = length
+
+	return desc, nil
+
+}
+
+// Get issues a HEAD request for a Manifest against its named endpoint in order
+// to construct a descriptor for the tag.  If the registry doesn't support HEADing
+// a manifest, fallback to GET.
+func (t *tags) Get(ctx context.Context, tag string) (distribution.Descriptor, error) {
+	ref, err := reference.WithTag(t.name, tag)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	u, err := t.ub.BuildManifestURL(ref)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+
+	newRequest := func(method string) (*http.Response, error) {
+		req, err := http.NewRequest(method, u, nil)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, t := range distribution.ManifestMediaTypes() {
+			req.Header.Add("Accept", t)
+		}
+		resp, err := t.client.Do(req)
+		return resp, err
+	}
+
+	resp, err := newRequest("HEAD")
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	defer resp.Body.Close()
+
+	switch {
+	case resp.StatusCode >= 200 && resp.StatusCode < 400 && len(resp.Header.Get("Docker-Content-Digest")) > 0:
+		// if the response is a success AND a Docker-Content-Digest can be retrieved from the headers
+		return descriptorFromResponse(resp)
+	default:
+		// if the response is an error - there will be no body to decode.
+		// Issue a GET request:
+		//   - for data from a server that does not handle HEAD
+		//   - to get error details in case of a failure
+		resp, err = newRequest("GET")
+		if err != nil {
+			return distribution.Descriptor{}, err
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode >= 200 && resp.StatusCode < 400 {
+			return descriptorFromResponse(resp)
+		}
+		return distribution.Descriptor{}, HandleErrorResponse(resp)
+	}
+}
+
+func (t *tags) Lookup(ctx context.Context, digest distribution.Descriptor) ([]string, error) {
+	panic("not implemented")
+}
+
+func (t *tags) Tag(ctx context.Context, tag string, desc distribution.Descriptor) error {
+	panic("not implemented")
+}
+
+func (t *tags) Untag(ctx context.Context, tag string) error {
+	panic("not implemented")
+}
+
+type manifests struct {
+	name   reference.Named
+	ub     *v2.URLBuilder
+	client *http.Client
+	etags  map[string]string
+}
+
+func (ms *manifests) Exists(ctx context.Context, dgst digest.Digest) (bool, error) {
+	ref, err := reference.WithDigest(ms.name, dgst)
+	if err != nil {
+		return false, err
+	}
+	u, err := ms.ub.BuildManifestURL(ref)
+	if err != nil {
+		return false, err
+	}
+
+	resp, err := ms.client.Head(u)
+	if err != nil {
+		return false, err
+	}
+
+	if SuccessStatus(resp.StatusCode) {
+		return true, nil
+	} else if resp.StatusCode == http.StatusNotFound {
+		return false, nil
+	}
+	return false, HandleErrorResponse(resp)
+}
+
+// AddEtagToTag allows a client to supply an eTag to Get which will be
+// used for a conditional HTTP request.  If the eTag matches, a nil manifest
+// and ErrManifestNotModified error will be returned. etag is automatically
+// quoted when added to this map.
+func AddEtagToTag(tag, etag string) distribution.ManifestServiceOption {
+	return etagOption{tag, etag}
+}
+
+type etagOption struct{ tag, etag string }
+
+func (o etagOption) Apply(ms distribution.ManifestService) error {
+	if ms, ok := ms.(*manifests); ok {
+		ms.etags[o.tag] = fmt.Sprintf(`"%s"`, o.etag)
+		return nil
+	}
+	return fmt.Errorf("etag options is a client-only option")
+}
+
+// ReturnContentDigest allows a client to set a the content digest on
+// a successful request from the 'Docker-Content-Digest' header. This
+// returned digest is represents the digest which the registry uses
+// to refer to the content and can be used to delete the content.
+func ReturnContentDigest(dgst *digest.Digest) distribution.ManifestServiceOption {
+	return contentDigestOption{dgst}
+}
+
+type contentDigestOption struct{ digest *digest.Digest }
+
+func (o contentDigestOption) Apply(ms distribution.ManifestService) error {
+	return nil
+}
+
+func (ms *manifests) Get(ctx context.Context, dgst digest.Digest, options ...distribution.ManifestServiceOption) (distribution.Manifest, error) {
+	var (
+		digestOrTag string
+		ref         reference.Named
+		err         error
+		contentDgst *digest.Digest
+		mediaTypes  []string
+	)
+
+	for _, option := range options {
+		switch opt := option.(type) {
+		case distribution.WithTagOption:
+			digestOrTag = opt.Tag
+			ref, err = reference.WithTag(ms.name, opt.Tag)
+			if err != nil {
+				return nil, err
+			}
+		case contentDigestOption:
+			contentDgst = opt.digest
+		case distribution.WithManifestMediaTypesOption:
+			mediaTypes = opt.MediaTypes
+		default:
+			err := option.Apply(ms)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	if digestOrTag == "" {
+		digestOrTag = dgst.String()
+		ref, err = reference.WithDigest(ms.name, dgst)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if len(mediaTypes) == 0 {
+		mediaTypes = distribution.ManifestMediaTypes()
+	}
+
+	u, err := ms.ub.BuildManifestURL(ref)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest("GET", u, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, t := range mediaTypes {
+		req.Header.Add("Accept", t)
+	}
+
+	if _, ok := ms.etags[digestOrTag]; ok {
+		req.Header.Set("If-None-Match", ms.etags[digestOrTag])
+	}
+
+	resp, err := ms.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode == http.StatusNotModified {
+		return nil, distribution.ErrManifestNotModified
+	} else if SuccessStatus(resp.StatusCode) {
+		if contentDgst != nil {
+			dgst, err := digest.Parse(resp.Header.Get("Docker-Content-Digest"))
+			if err == nil {
+				*contentDgst = dgst
+			}
+		}
+		mt := resp.Header.Get("Content-Type")
+		body, err := ioutil.ReadAll(resp.Body)
+
+		if err != nil {
+			return nil, err
+		}
+		m, _, err := distribution.UnmarshalManifest(mt, body)
+		if err != nil {
+			return nil, err
+		}
+		return m, nil
+	}
+	return nil, HandleErrorResponse(resp)
+}
+
+// Put puts a manifest.  A tag can be specified using an options parameter which uses some shared state to hold the
+// tag name in order to build the correct upload URL.
+func (ms *manifests) Put(ctx context.Context, m distribution.Manifest, options ...distribution.ManifestServiceOption) (digest.Digest, error) {
+	ref := ms.name
+	var tagged bool
+
+	for _, option := range options {
+		if opt, ok := option.(distribution.WithTagOption); ok {
+			var err error
+			ref, err = reference.WithTag(ref, opt.Tag)
+			if err != nil {
+				return "", err
+			}
+			tagged = true
+		} else {
+			err := option.Apply(ms)
+			if err != nil {
+				return "", err
+			}
+		}
+	}
+	mediaType, p, err := m.Payload()
+	if err != nil {
+		return "", err
+	}
+
+	if !tagged {
+		// generate a canonical digest and Put by digest
+		_, d, err := distribution.UnmarshalManifest(mediaType, p)
+		if err != nil {
+			return "", err
+		}
+		ref, err = reference.WithDigest(ref, d.Digest)
+		if err != nil {
+			return "", err
+		}
+	}
+
+	manifestURL, err := ms.ub.BuildManifestURL(ref)
+	if err != nil {
+		return "", err
+	}
+
+	putRequest, err := http.NewRequest("PUT", manifestURL, bytes.NewReader(p))
+	if err != nil {
+		return "", err
+	}
+
+	putRequest.Header.Set("Content-Type", mediaType)
+
+	resp, err := ms.client.Do(putRequest)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if SuccessStatus(resp.StatusCode) {
+		dgstHeader := resp.Header.Get("Docker-Content-Digest")
+		dgst, err := digest.Parse(dgstHeader)
+		if err != nil {
+			return "", err
+		}
+
+		return dgst, nil
+	}
+
+	return "", HandleErrorResponse(resp)
+}
+
+func (ms *manifests) Delete(ctx context.Context, dgst digest.Digest) error {
+	ref, err := reference.WithDigest(ms.name, dgst)
+	if err != nil {
+		return err
+	}
+	u, err := ms.ub.BuildManifestURL(ref)
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequest("DELETE", u, nil)
+	if err != nil {
+		return err
+	}
+
+	resp, err := ms.client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if SuccessStatus(resp.StatusCode) {
+		return nil
+	}
+	return HandleErrorResponse(resp)
+}
+
+// todo(richardscothern): Restore interface and implementation with merge of #1050
+/*func (ms *manifests) Enumerate(ctx context.Context, manifests []distribution.Manifest, last distribution.Manifest) (n int, err error) {
+	panic("not supported")
+}*/
+
+type blobs struct {
+	name   reference.Named
+	ub     *v2.URLBuilder
+	client *http.Client
+
+	statter distribution.BlobDescriptorService
+	distribution.BlobDeleter
+}
+
+func sanitizeLocation(location, base string) (string, error) {
+	baseURL, err := url.Parse(base)
+	if err != nil {
+		return "", err
+	}
+
+	locationURL, err := url.Parse(location)
+	if err != nil {
+		return "", err
+	}
+
+	return baseURL.ResolveReference(locationURL).String(), nil
+}
+
+func (bs *blobs) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
+	return bs.statter.Stat(ctx, dgst)
+
+}
+
+func (bs *blobs) Get(ctx context.Context, dgst digest.Digest) ([]byte, error) {
+	reader, err := bs.Open(ctx, dgst)
+	if err != nil {
+		return nil, err
+	}
+	defer reader.Close()
+
+	return ioutil.ReadAll(reader)
+}
+
+func (bs *blobs) Open(ctx context.Context, dgst digest.Digest) (distribution.ReadSeekCloser, error) {
+	ref, err := reference.WithDigest(bs.name, dgst)
+	if err != nil {
+		return nil, err
+	}
+	blobURL, err := bs.ub.BuildBlobURL(ref)
+	if err != nil {
+		return nil, err
+	}
+
+	return transport.NewHTTPReadSeeker(bs.client, blobURL,
+		func(resp *http.Response) error {
+			if resp.StatusCode == http.StatusNotFound {
+				return distribution.ErrBlobUnknown
+			}
+			return HandleErrorResponse(resp)
+		}), nil
+}
+
+func (bs *blobs) ServeBlob(ctx context.Context, w http.ResponseWriter, r *http.Request, dgst digest.Digest) error {
+	panic("not implemented")
+}
+
+func (bs *blobs) Put(ctx context.Context, mediaType string, p []byte) (distribution.Descriptor, error) {
+	writer, err := bs.Create(ctx)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	dgstr := digest.Canonical.Digester()
+	n, err := io.Copy(writer, io.TeeReader(bytes.NewReader(p), dgstr.Hash()))
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	if n < int64(len(p)) {
+		return distribution.Descriptor{}, fmt.Errorf("short copy: wrote %d of %d", n, len(p))
+	}
+
+	desc := distribution.Descriptor{
+		MediaType: mediaType,
+		Size:      int64(len(p)),
+		Digest:    dgstr.Digest(),
+	}
+
+	return writer.Commit(ctx, desc)
+}
+
+type optionFunc func(interface{}) error
+
+func (f optionFunc) Apply(v interface{}) error {
+	return f(v)
+}
+
+// WithMountFrom returns a BlobCreateOption which designates that the blob should be
+// mounted from the given canonical reference.
+func WithMountFrom(ref reference.Canonical) distribution.BlobCreateOption {
+	return optionFunc(func(v interface{}) error {
+		opts, ok := v.(*distribution.CreateOptions)
+		if !ok {
+			return fmt.Errorf("unexpected options type: %T", v)
+		}
+
+		opts.Mount.ShouldMount = true
+		opts.Mount.From = ref
+
+		return nil
+	})
+}
+
+func (bs *blobs) Create(ctx context.Context, options ...distribution.BlobCreateOption) (distribution.BlobWriter, error) {
+	var opts distribution.CreateOptions
+
+	for _, option := range options {
+		err := option.Apply(&opts)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var values []url.Values
+
+	if opts.Mount.ShouldMount {
+		values = append(values, url.Values{"from": {opts.Mount.From.Name()}, "mount": {opts.Mount.From.Digest().String()}})
+	}
+
+	u, err := bs.ub.BuildBlobUploadURL(bs.name, values...)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest("POST", u, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := bs.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	switch resp.StatusCode {
+	case http.StatusCreated:
+		desc, err := bs.statter.Stat(ctx, opts.Mount.From.Digest())
+		if err != nil {
+			return nil, err
+		}
+		return nil, distribution.ErrBlobMounted{From: opts.Mount.From, Descriptor: desc}
+	case http.StatusAccepted:
+		// TODO(dmcgowan): Check for invalid UUID
+		uuid := resp.Header.Get("Docker-Upload-UUID")
+		location, err := sanitizeLocation(resp.Header.Get("Location"), u)
+		if err != nil {
+			return nil, err
+		}
+
+		return &httpBlobUpload{
+			statter:   bs.statter,
+			client:    bs.client,
+			uuid:      uuid,
+			startedAt: time.Now(),
+			location:  location,
+		}, nil
+	default:
+		return nil, HandleErrorResponse(resp)
+	}
+}
+
+func (bs *blobs) Resume(ctx context.Context, id string) (distribution.BlobWriter, error) {
+	panic("not implemented")
+}
+
+func (bs *blobs) Delete(ctx context.Context, dgst digest.Digest) error {
+	return bs.statter.Clear(ctx, dgst)
+}
+
+type blobStatter struct {
+	name   reference.Named
+	ub     *v2.URLBuilder
+	client *http.Client
+}
+
+func (bs *blobStatter) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
+	ref, err := reference.WithDigest(bs.name, dgst)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	u, err := bs.ub.BuildBlobURL(ref)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+
+	resp, err := bs.client.Head(u)
+	if err != nil {
+		return distribution.Descriptor{}, err
+	}
+	defer resp.Body.Close()
+
+	if SuccessStatus(resp.StatusCode) {
+		lengthHeader := resp.Header.Get("Content-Length")
+		if lengthHeader == "" {
+			return distribution.Descriptor{}, fmt.Errorf("missing content-length header for request: %s", u)
+		}
+
+		length, err := strconv.ParseInt(lengthHeader, 10, 64)
+		if err != nil {
+			return distribution.Descriptor{}, fmt.Errorf("error parsing content-length: %v", err)
+		}
+
+		return distribution.Descriptor{
+			MediaType: resp.Header.Get("Content-Type"),
+			Size:      length,
+			Digest:    dgst,
+		}, nil
+	} else if resp.StatusCode == http.StatusNotFound {
+		return distribution.Descriptor{}, distribution.ErrBlobUnknown
+	}
+	return distribution.Descriptor{}, HandleErrorResponse(resp)
+}
+
+func buildCatalogValues(maxEntries int, last string) url.Values {
+	values := url.Values{}
+
+	if maxEntries > 0 {
+		values.Add("n", strconv.Itoa(maxEntries))
+	}
+
+	if last != "" {
+		values.Add("last", last)
+	}
+
+	return values
+}
+
+func (bs *blobStatter) Clear(ctx context.Context, dgst digest.Digest) error {
+	ref, err := reference.WithDigest(bs.name, dgst)
+	if err != nil {
+		return err
+	}
+	blobURL, err := bs.ub.BuildBlobURL(ref)
+	if err != nil {
+		return err
+	}
+
+	req, err := http.NewRequest("DELETE", blobURL, nil)
+	if err != nil {
+		return err
+	}
+
+	resp, err := bs.client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if SuccessStatus(resp.StatusCode) {
+		return nil
+	}
+	return HandleErrorResponse(resp)
+}
+
+func (bs *blobStatter) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
+	return nil
+}