diff options
Diffstat (limited to 'vendor/github.com/docker/distribution/reference/reference.go')
-rw-r--r-- | vendor/github.com/docker/distribution/reference/reference.go | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/vendor/github.com/docker/distribution/reference/reference.go b/vendor/github.com/docker/distribution/reference/reference.go new file mode 100644 index 000000000..2f66cca87 --- /dev/null +++ b/vendor/github.com/docker/distribution/reference/reference.go @@ -0,0 +1,433 @@ +// Package reference provides a general type to represent any way of referencing images within the registry. +// Its main purpose is to abstract tags and digests (content-addressable hash). +// +// Grammar +// +// reference := name [ ":" tag ] [ "@" digest ] +// name := [domain '/'] path-component ['/' path-component]* +// domain := domain-component ['.' domain-component]* [':' port-number] +// domain-component := /([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])/ +// port-number := /[0-9]+/ +// path-component := alpha-numeric [separator alpha-numeric]* +// alpha-numeric := /[a-z0-9]+/ +// separator := /[_.]|__|[-]*/ +// +// tag := /[\w][\w.-]{0,127}/ +// +// digest := digest-algorithm ":" digest-hex +// digest-algorithm := digest-algorithm-component [ digest-algorithm-separator digest-algorithm-component ]* +// digest-algorithm-separator := /[+.-_]/ +// digest-algorithm-component := /[A-Za-z][A-Za-z0-9]*/ +// digest-hex := /[0-9a-fA-F]{32,}/ ; At least 128 bit digest value +// +// identifier := /[a-f0-9]{64}/ +// short-identifier := /[a-f0-9]{6,64}/ +package reference + +import ( + "errors" + "fmt" + "strings" + + "github.com/opencontainers/go-digest" +) + +const ( + // NameTotalLengthMax is the maximum total number of characters in a repository name. + NameTotalLengthMax = 255 +) + +var ( + // ErrReferenceInvalidFormat represents an error while trying to parse a string as a reference. + ErrReferenceInvalidFormat = errors.New("invalid reference format") + + // ErrTagInvalidFormat represents an error while trying to parse a string as a tag. + ErrTagInvalidFormat = errors.New("invalid tag format") + + // ErrDigestInvalidFormat represents an error while trying to parse a string as a tag. + ErrDigestInvalidFormat = errors.New("invalid digest format") + + // ErrNameContainsUppercase is returned for invalid repository names that contain uppercase characters. + ErrNameContainsUppercase = errors.New("repository name must be lowercase") + + // ErrNameEmpty is returned for empty, invalid repository names. + ErrNameEmpty = errors.New("repository name must have at least one component") + + // ErrNameTooLong is returned when a repository name is longer than NameTotalLengthMax. + ErrNameTooLong = fmt.Errorf("repository name must not be more than %v characters", NameTotalLengthMax) + + // ErrNameNotCanonical is returned when a name is not canonical. + ErrNameNotCanonical = errors.New("repository name must be canonical") +) + +// Reference is an opaque object reference identifier that may include +// modifiers such as a hostname, name, tag, and digest. +type Reference interface { + // String returns the full reference + String() string +} + +// Field provides a wrapper type for resolving correct reference types when +// working with encoding. +type Field struct { + reference Reference +} + +// AsField wraps a reference in a Field for encoding. +func AsField(reference Reference) Field { + return Field{reference} +} + +// Reference unwraps the reference type from the field to +// return the Reference object. This object should be +// of the appropriate type to further check for different +// reference types. +func (f Field) Reference() Reference { + return f.reference +} + +// MarshalText serializes the field to byte text which +// is the string of the reference. +func (f Field) MarshalText() (p []byte, err error) { + return []byte(f.reference.String()), nil +} + +// UnmarshalText parses text bytes by invoking the +// reference parser to ensure the appropriately +// typed reference object is wrapped by field. +func (f *Field) UnmarshalText(p []byte) error { + r, err := Parse(string(p)) + if err != nil { + return err + } + + f.reference = r + return nil +} + +// Named is an object with a full name +type Named interface { + Reference + Name() string +} + +// Tagged is an object which has a tag +type Tagged interface { + Reference + Tag() string +} + +// NamedTagged is an object including a name and tag. +type NamedTagged interface { + Named + Tag() string +} + +// Digested is an object which has a digest +// in which it can be referenced by +type Digested interface { + Reference + Digest() digest.Digest +} + +// Canonical reference is an object with a fully unique +// name including a name with domain and digest +type Canonical interface { + Named + Digest() digest.Digest +} + +// namedRepository is a reference to a repository with a name. +// A namedRepository has both domain and path components. +type namedRepository interface { + Named + Domain() string + Path() string +} + +// Domain returns the domain part of the Named reference +func Domain(named Named) string { + if r, ok := named.(namedRepository); ok { + return r.Domain() + } + domain, _ := splitDomain(named.Name()) + return domain +} + +// Path returns the name without the domain part of the Named reference +func Path(named Named) (name string) { + if r, ok := named.(namedRepository); ok { + return r.Path() + } + _, path := splitDomain(named.Name()) + return path +} + +func splitDomain(name string) (string, string) { + match := anchoredNameRegexp.FindStringSubmatch(name) + if len(match) != 3 { + return "", name + } + return match[1], match[2] +} + +// SplitHostname splits a named reference into a +// hostname and name string. If no valid hostname is +// found, the hostname is empty and the full value +// is returned as name +// DEPRECATED: Use Domain or Path +func SplitHostname(named Named) (string, string) { + if r, ok := named.(namedRepository); ok { + return r.Domain(), r.Path() + } + return splitDomain(named.Name()) +} + +// Parse parses s and returns a syntactically valid Reference. +// If an error was encountered it is returned, along with a nil Reference. +// NOTE: Parse will not handle short digests. +func Parse(s string) (Reference, error) { + matches := ReferenceRegexp.FindStringSubmatch(s) + if matches == nil { + if s == "" { + return nil, ErrNameEmpty + } + if ReferenceRegexp.FindStringSubmatch(strings.ToLower(s)) != nil { + return nil, ErrNameContainsUppercase + } + return nil, ErrReferenceInvalidFormat + } + + if len(matches[1]) > NameTotalLengthMax { + return nil, ErrNameTooLong + } + + var repo repository + + nameMatch := anchoredNameRegexp.FindStringSubmatch(matches[1]) + if nameMatch != nil && len(nameMatch) == 3 { + repo.domain = nameMatch[1] + repo.path = nameMatch[2] + } else { + repo.domain = "" + repo.path = matches[1] + } + + ref := reference{ + namedRepository: repo, + tag: matches[2], + } + if matches[3] != "" { + var err error + ref.digest, err = digest.Parse(matches[3]) + if err != nil { + return nil, err + } + } + + r := getBestReferenceType(ref) + if r == nil { + return nil, ErrNameEmpty + } + + return r, nil +} + +// ParseNamed parses s and returns a syntactically valid reference implementing +// the Named interface. The reference must have a name and be in the canonical +// form, otherwise an error is returned. +// If an error was encountered it is returned, along with a nil Reference. +// NOTE: ParseNamed will not handle short digests. +func ParseNamed(s string) (Named, error) { + named, err := ParseNormalizedNamed(s) + if err != nil { + return nil, err + } + if named.String() != s { + return nil, ErrNameNotCanonical + } + return named, nil +} + +// WithName returns a named object representing the given string. If the input +// is invalid ErrReferenceInvalidFormat will be returned. +func WithName(name string) (Named, error) { + if len(name) > NameTotalLengthMax { + return nil, ErrNameTooLong + } + + match := anchoredNameRegexp.FindStringSubmatch(name) + if match == nil || len(match) != 3 { + return nil, ErrReferenceInvalidFormat + } + return repository{ + domain: match[1], + path: match[2], + }, nil +} + +// WithTag combines the name from "name" and the tag from "tag" to form a +// reference incorporating both the name and the tag. +func WithTag(name Named, tag string) (NamedTagged, error) { + if !anchoredTagRegexp.MatchString(tag) { + return nil, ErrTagInvalidFormat + } + var repo repository + if r, ok := name.(namedRepository); ok { + repo.domain = r.Domain() + repo.path = r.Path() + } else { + repo.path = name.Name() + } + if canonical, ok := name.(Canonical); ok { + return reference{ + namedRepository: repo, + tag: tag, + digest: canonical.Digest(), + }, nil + } + return taggedReference{ + namedRepository: repo, + tag: tag, + }, nil +} + +// WithDigest combines the name from "name" and the digest from "digest" to form +// a reference incorporating both the name and the digest. +func WithDigest(name Named, digest digest.Digest) (Canonical, error) { + if !anchoredDigestRegexp.MatchString(digest.String()) { + return nil, ErrDigestInvalidFormat + } + var repo repository + if r, ok := name.(namedRepository); ok { + repo.domain = r.Domain() + repo.path = r.Path() + } else { + repo.path = name.Name() + } + if tagged, ok := name.(Tagged); ok { + return reference{ + namedRepository: repo, + tag: tagged.Tag(), + digest: digest, + }, nil + } + return canonicalReference{ + namedRepository: repo, + digest: digest, + }, nil +} + +// TrimNamed removes any tag or digest from the named reference. +func TrimNamed(ref Named) Named { + domain, path := SplitHostname(ref) + return repository{ + domain: domain, + path: path, + } +} + +func getBestReferenceType(ref reference) Reference { + if ref.Name() == "" { + // Allow digest only references + if ref.digest != "" { + return digestReference(ref.digest) + } + return nil + } + if ref.tag == "" { + if ref.digest != "" { + return canonicalReference{ + namedRepository: ref.namedRepository, + digest: ref.digest, + } + } + return ref.namedRepository + } + if ref.digest == "" { + return taggedReference{ + namedRepository: ref.namedRepository, + tag: ref.tag, + } + } + + return ref +} + +type reference struct { + namedRepository + tag string + digest digest.Digest +} + +func (r reference) String() string { + return r.Name() + ":" + r.tag + "@" + r.digest.String() +} + +func (r reference) Tag() string { + return r.tag +} + +func (r reference) Digest() digest.Digest { + return r.digest +} + +type repository struct { + domain string + path string +} + +func (r repository) String() string { + return r.Name() +} + +func (r repository) Name() string { + if r.domain == "" { + return r.path + } + return r.domain + "/" + r.path +} + +func (r repository) Domain() string { + return r.domain +} + +func (r repository) Path() string { + return r.path +} + +type digestReference digest.Digest + +func (d digestReference) String() string { + return digest.Digest(d).String() +} + +func (d digestReference) Digest() digest.Digest { + return digest.Digest(d) +} + +type taggedReference struct { + namedRepository + tag string +} + +func (t taggedReference) String() string { + return t.Name() + ":" + t.tag +} + +func (t taggedReference) Tag() string { + return t.tag +} + +type canonicalReference struct { + namedRepository + digest digest.Digest +} + +func (c canonicalReference) String() string { + return c.Name() + "@" + c.digest.String() +} + +func (c canonicalReference) Digest() digest.Digest { + return c.digest +} |