Update to provide small and clear interfaces
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
This commit is contained in:
Derek McGowan
parent
f8c09b6a7d
commit
31a448a628
13 changed files with 901 additions and 648 deletions
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@ -7,11 +7,13 @@
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//
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// // repository.go
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// repository := hostname ['/' component]+
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// hostname := component [':' port-number]
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// hostname := hostcomponent [':' port-number]
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// component := alpha-numeric [separator alpha-numeric]*
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// hostcomponent := [hostpart '.']* hostpart
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// alpha-numeric := /[a-zA-Z0-9]+/
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// separator := /[._-]/
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// separator := /[_-]/
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// port-number := /[0-9]+/
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// hostpart := /([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])/
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//
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// // tag.go
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// tag := /[\w][\w.-]{0,127}/
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@ -20,167 +22,224 @@
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// digest := digest-algorithm ":" digest-hex
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// digest-algorithm := digest-algorithm-component [ digest-algorithm-separator digest-algorithm-component ]
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// digest-algorithm-separator := /[+.-_]/
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// digest-algorithm-component := /[A-Za-z]/ /[A-Za-z0-9]*/
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// digest-hex := /[A-Za-z0-9_-]+/ ; supports hex bytes or url safe base64
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// digest-algorithm-component := /[A-Za-z][A-Za-z0-9]*/
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// digest-hex := /[0-9a-fA-F]{32,}/ ; Atleast 128 bit digest value
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package reference
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import (
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"errors"
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"regexp"
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"fmt"
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"github.com/docker/distribution/digest"
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)
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// ErrReferenceInvalidFormat represents an error while trying to parse a string as a reference.
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var ErrReferenceInvalidFormat = errors.New("invalid reference format")
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const (
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// NameTotalLengthMax is the maximum total number of characters in a repository name.
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NameTotalLengthMax = 255
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)
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// Reference abstracts types that reference images in a certain way.
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var (
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// ErrReferenceInvalidFormat represents an error while trying to parse a string as a reference.
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ErrReferenceInvalidFormat = errors.New("invalid reference format")
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// ErrNameEmpty is returned for empty, invalid repository names.
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ErrNameEmpty = errors.New("repository name must have at least one component")
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// ErrNameTooLong is returned when a repository name is longer than
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// RepositoryNameTotalLengthMax
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ErrNameTooLong = fmt.Errorf("repository name must not be more than %v characters", NameTotalLengthMax)
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)
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// Reference is an opaque object reference identifier that may include
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// modifiers such as a hostname, name, tag, and digest.
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type Reference interface {
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// Repository returns the repository part of a reference
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Repository() Repository
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// String returns the entire reference, including the repository part
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// String returns the full reference
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String() string
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}
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func parseHostname(s string) (hostname, tail string) {
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tail = s
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i := regexp.MustCompile(`^` + RepositoryNameHostnameRegexp.String()).FindStringIndex(s)
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if i == nil {
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return
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}
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return s[:i[1]], s[i[1]:]
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// Named is an object with a full name
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type Named interface {
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Name() string
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}
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func parseRepositoryName(s string) (repo, tail string) {
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tail = s
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i := regexp.MustCompile(`^/(?:` + RepositoryNameComponentRegexp.String() + `/)*` + RepositoryNameComponentRegexp.String()).FindStringIndex(s)
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if i == nil {
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return
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}
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return s[:i[1]], s[i[1]:]
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// Tagged is an object which has a tag
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type Tagged interface {
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Tag() string
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}
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func parseTag(s string) (tag Tag, tail string) {
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tail = s
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if len(s) == 0 || s[0] != ':' {
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return
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}
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tag, err := NewTag(s[1:])
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if err != nil {
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return
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}
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tail = s[len(tag)+1:]
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return
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// Digested is an object which has a digest
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// in which it can be referenced by
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type Digested interface {
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Digest() digest.Digest
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}
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func parseDigest(s string) (dgst digest.Digest, tail string) {
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tail = s
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if len(s) == 0 || s[0] != '@' {
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return
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// Canonical reference is an object with a fully unique
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// name including a name with hostname and digest
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type Canonical interface {
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Reference
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Named
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Digested
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}
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// SplitHostname splits a named reference into a
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// hostname and name string. If no valid hostname is
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// found, the hostname is empty and the full value
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// is returned as name
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func SplitHostname(named Named) (string, string) {
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name := named.Name()
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match := anchoredNameRegexp.FindStringSubmatch(name)
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if match == nil || len(match) != 3 {
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return "", name
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}
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dgst, err := digest.ParseDigest(s[1:])
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if err != nil {
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return
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}
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tail = s[len(dgst)+1:]
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return
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return match[1], match[2]
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}
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// Parse parses s and returns a syntactically valid Reference.
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// If an error was encountered it is returned, along with a nil Reference.
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// NOTE: Parse will not handle short digests.
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func Parse(s string) (Reference, error) {
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hostname, s := parseHostname(s)
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name, s := parseRepositoryName(s)
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repository := Repository{Hostname: hostname, Name: name}
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if err := repository.Validate(); err != nil {
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return nil, err
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}
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tag, s := parseTag(s)
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dgst, s := parseDigest(s)
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if len(s) > 0 {
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matches := ReferenceRegexp.FindStringSubmatch(s)
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if matches == nil {
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if s == "" {
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return nil, ErrNameEmpty
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}
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// TODO(dmcgowan): Provide more specific and helpful error
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return nil, ErrReferenceInvalidFormat
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}
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if dgst != "" {
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return DigestReference{repository: repository, digest: dgst, tag: tag}, nil
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if len(matches[1]) > NameTotalLengthMax {
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return nil, ErrNameTooLong
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}
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if tag != "" {
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return TagReference{repository: repository, tag: tag}, nil
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ref := reference{
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name: matches[1],
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tag: matches[2],
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}
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return nil, ErrReferenceInvalidFormat
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}
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// DigestReference represents a reference of the form `repository@sha256:deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef`.
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// Implements the Reference interface.
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type DigestReference struct {
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repository Repository
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digest digest.Digest
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tag Tag
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}
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// Repository returns the repository part.
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func (r DigestReference) Repository() Repository { return r.repository }
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// String returns the full string reference.
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func (r DigestReference) String() string {
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return r.repository.String() + "@" + string(r.digest)
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}
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// NewDigestReference returns an initialized DigestReference.
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func NewDigestReference(canonicalRepository string, digest digest.Digest, optionalTag Tag) (DigestReference, error) {
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ref := DigestReference{}
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repo, err := NewRepository(canonicalRepository)
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if err != nil {
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return ref, err
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}
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ref.repository = repo
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if err := digest.Validate(); err != nil {
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return ref, err
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}
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ref.digest = digest
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if len(optionalTag) > 0 {
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if err := optionalTag.Validate(); err != nil {
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return ref, err
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if matches[3] != "" {
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var err error
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ref.digest, err = digest.ParseDigest(matches[3])
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if err != nil {
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return nil, err
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}
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ref.tag = optionalTag
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}
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return ref, err
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}
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// TagReference represents a reference of the form `repository:tag`.
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// Implements the Reference interface.
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type TagReference struct {
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repository Repository
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tag Tag
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}
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// Repository returns the repository part.
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func (r TagReference) Repository() Repository { return r.repository }
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// String returns the full string reference.
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func (r TagReference) String() string {
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return r.repository.String() + ":" + string(r.tag)
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}
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// NewTagReference returns an initialized TagReference.
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func NewTagReference(canonicalRepository string, tagName string) (TagReference, error) {
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ref := TagReference{}
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repo, err := NewRepository(canonicalRepository)
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if err != nil {
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return ref, err
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r := getBestReferenceType(ref)
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if r == nil {
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return nil, ErrNameEmpty
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}
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ref.repository = repo
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tag, err := NewTag(tagName)
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if err != nil {
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return ref, err
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}
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ref.tag = tag
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return ref, err
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return r, nil
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}
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// ParseNamed parses the input string and returns a named
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// object representing the given string. If the input is
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// invalid ErrReferenceInvalidFormat will be returned.
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func ParseNamed(name string) (Named, error) {
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if !anchoredNameRegexp.MatchString(name) {
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return nil, ErrReferenceInvalidFormat
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}
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return repository(name), nil
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}
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func getBestReferenceType(ref reference) Reference {
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if ref.name == "" {
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// Allow digest only references
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if ref.digest != "" {
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return digestReference(ref.digest)
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}
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return nil
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}
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if ref.tag == "" {
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if ref.digest != "" {
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return canonicalReference{
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name: ref.name,
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digest: ref.digest,
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}
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}
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return repository(ref.name)
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}
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if ref.digest == "" {
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return taggedReference{
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name: ref.name,
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tag: ref.tag,
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}
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}
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return ref
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}
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type reference struct {
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name string
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tag string
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digest digest.Digest
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}
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func (r reference) String() string {
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return r.name + ":" + r.tag + "@" + r.digest.String()
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}
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func (r reference) Name() string {
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return r.name
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}
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func (r reference) Tag() string {
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return r.tag
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}
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func (r reference) Digest() digest.Digest {
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return r.digest
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}
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type repository string
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func (r repository) String() string {
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return string(r)
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}
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func (r repository) Name() string {
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return string(r)
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}
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type digestReference digest.Digest
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func (d digestReference) String() string {
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return d.String()
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}
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func (d digestReference) Digest() digest.Digest {
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return digest.Digest(d)
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}
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type taggedReference struct {
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name string
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tag string
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}
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func (t taggedReference) String() string {
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return t.name + ":" + t.tag
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}
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func (t taggedReference) Name() string {
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return t.name
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}
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func (t taggedReference) Tag() string {
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return t.tag
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}
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type canonicalReference struct {
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name string
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digest digest.Digest
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}
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func (c canonicalReference) String() string {
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return c.name + "@" + c.digest.String()
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}
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func (c canonicalReference) Name() string {
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return c.name
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}
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func (c canonicalReference) Digest() digest.Digest {
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return c.digest
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}
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