diff options
Diffstat (limited to 'vendor/github.com/distribution/reference/regexp.go')
| -rw-r--r-- | vendor/github.com/distribution/reference/regexp.go | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/vendor/github.com/distribution/reference/regexp.go b/vendor/github.com/distribution/reference/regexp.go new file mode 100644 index 0000000..65bc49d --- /dev/null +++ b/vendor/github.com/distribution/reference/regexp.go @@ -0,0 +1,163 @@ +package reference + +import ( + "regexp" + "strings" +) + +// DigestRegexp matches well-formed digests, including algorithm (e.g. "sha256:<encoded>"). +var DigestRegexp = regexp.MustCompile(digestPat) + +// DomainRegexp matches hostname or IP-addresses, optionally including a port +// number. It defines the structure of potential domain components that may be +// part of image names. This is purposely a subset of what is allowed by DNS to +// ensure backwards compatibility with Docker image names. It may be a subset of +// DNS domain name, an IPv4 address in decimal format, or an IPv6 address between +// square brackets (excluding zone identifiers as defined by [RFC 6874] or special +// addresses such as IPv4-Mapped). +// +// [RFC 6874]: https://www.rfc-editor.org/rfc/rfc6874. +var DomainRegexp = regexp.MustCompile(domainAndPort) + +// IdentifierRegexp is the format for string identifier used as a +// content addressable identifier using sha256. These identifiers +// are like digests without the algorithm, since sha256 is used. +var IdentifierRegexp = regexp.MustCompile(identifier) + +// NameRegexp is the format for the name component of references, including +// an optional domain and port, but without tag or digest suffix. +var NameRegexp = regexp.MustCompile(namePat) + +// ReferenceRegexp is the full supported format of a reference. The regexp +// is anchored and has capturing groups for name, tag, and digest +// components. +var ReferenceRegexp = regexp.MustCompile(referencePat) + +// TagRegexp matches valid tag names. From [docker/docker:graph/tags.go]. +// +// [docker/docker:graph/tags.go]: https://github.com/moby/moby/blob/v1.6.0/graph/tags.go#L26-L28 +var TagRegexp = regexp.MustCompile(tag) + +const ( + // alphanumeric defines the alphanumeric atom, typically a + // component of names. This only allows lower case characters and digits. + alphanumeric = `[a-z0-9]+` + + // separator defines the separators allowed to be embedded in name + // components. This allows one period, one or two underscore and multiple + // dashes. Repeated dashes and underscores are intentionally treated + // differently. In order to support valid hostnames as name components, + // supporting repeated dash was added. Additionally double underscore is + // now allowed as a separator to loosen the restriction for previously + // supported names. + separator = `(?:[._]|__|[-]+)` + + // localhost is treated as a special value for domain-name. Any other + // domain-name without a "." or a ":port" are considered a path component. + localhost = `localhost` + + // domainNameComponent restricts the registry domain component of a + // repository name to start with a component as defined by DomainRegexp. + domainNameComponent = `(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])` + + // optionalPort matches an optional port-number including the port separator + // (e.g. ":80"). + optionalPort = `(?::[0-9]+)?` + + // tag matches valid tag names. From docker/docker:graph/tags.go. + tag = `[\w][\w.-]{0,127}` + + // digestPat matches well-formed digests, including algorithm (e.g. "sha256:<encoded>"). + // + // TODO(thaJeztah): this should follow the same rules as https://pkg.go.dev/github.com/opencontainers/go-digest@v1.0.0#DigestRegexp + // so that go-digest defines the canonical format. Note that the go-digest is + // more relaxed: + // - it allows multiple algorithms (e.g. "sha256+b64:<encoded>") to allow + // future expansion of supported algorithms. + // - it allows the "<encoded>" value to use urlsafe base64 encoding as defined + // in [rfc4648, section 5]. + // + // [rfc4648, section 5]: https://www.rfc-editor.org/rfc/rfc4648#section-5. + digestPat = `[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}` + + // identifier is the format for a content addressable identifier using sha256. + // These identifiers are like digests without the algorithm, since sha256 is used. + identifier = `([a-f0-9]{64})` + + // ipv6address are enclosed between square brackets and may be represented + // in many ways, see rfc5952. Only IPv6 in compressed or uncompressed format + // are allowed, IPv6 zone identifiers (rfc6874) or Special addresses such as + // IPv4-Mapped are deliberately excluded. + ipv6address = `\[(?:[a-fA-F0-9:]+)\]` +) + +var ( + // domainName defines the structure of potential domain components + // that may be part of image names. This is purposely a subset of what is + // allowed by DNS to ensure backwards compatibility with Docker image + // names. This includes IPv4 addresses on decimal format. + domainName = domainNameComponent + anyTimes(`\.`+domainNameComponent) + + // host defines the structure of potential domains based on the URI + // Host subcomponent on rfc3986. It may be a subset of DNS domain name, + // or an IPv4 address in decimal format, or an IPv6 address between square + // brackets (excluding zone identifiers as defined by rfc6874 or special + // addresses such as IPv4-Mapped). + host = `(?:` + domainName + `|` + ipv6address + `)` + + // allowed by the URI Host subcomponent on rfc3986 to ensure backwards + // compatibility with Docker image names. + domainAndPort = host + optionalPort + + // anchoredTagRegexp matches valid tag names, anchored at the start and + // end of the matched string. + anchoredTagRegexp = regexp.MustCompile(anchored(tag)) + + // anchoredDigestRegexp matches valid digests, anchored at the start and + // end of the matched string. + anchoredDigestRegexp = regexp.MustCompile(anchored(digestPat)) + + // pathComponent restricts path-components to start with an alphanumeric + // character, with following parts able to be separated by a separator + // (one period, one or two underscore and multiple dashes). + pathComponent = alphanumeric + anyTimes(separator+alphanumeric) + + // remoteName matches the remote-name of a repository. It consists of one + // or more forward slash (/) delimited path-components: + // + // pathComponent[[/pathComponent] ...] // e.g., "library/ubuntu" + remoteName = pathComponent + anyTimes(`/`+pathComponent) + namePat = optional(domainAndPort+`/`) + remoteName + + // anchoredNameRegexp is used to parse a name value, capturing the + // domain and trailing components. + anchoredNameRegexp = regexp.MustCompile(anchored(optional(capture(domainAndPort), `/`), capture(remoteName))) + + referencePat = anchored(capture(namePat), optional(`:`, capture(tag)), optional(`@`, capture(digestPat))) + + // anchoredIdentifierRegexp is used to check or match an + // identifier value, anchored at start and end of string. + anchoredIdentifierRegexp = regexp.MustCompile(anchored(identifier)) +) + +// optional wraps the expression in a non-capturing group and makes the +// production optional. +func optional(res ...string) string { + return `(?:` + strings.Join(res, "") + `)?` +} + +// anyTimes wraps the expression in a non-capturing group that can occur +// any number of times. +func anyTimes(res ...string) string { + return `(?:` + strings.Join(res, "") + `)*` +} + +// capture wraps the expression in a capturing group. +func capture(res ...string) string { + return `(` + strings.Join(res, "") + `)` +} + +// anchored anchors the regular expression by adding start and end delimiters. +func anchored(res ...string) string { + return `^` + strings.Join(res, "") + `$` +} |