hook

var (

	// DomainRegexp 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.
	DomainRegexp = expression(
		domainComponentRegexp,
		optional(repeated(literal(`.`), domainComponentRegexp)),
		optional(literal(`:`), match(`[0-9]+`)))

	// TagRegexp matches valid tag names. From docker/docker:graph/tags.go.
	TagRegexp = match(`[\w][\w.-]{0,127}`)

	// DigestRegexp matches valid digests.
	DigestRegexp = match(`[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`)

	// NameRegexp is the format for the name component of references. The
	// regexp has capturing groups for the domain and name part omitting
	// the separating forward slash from either.
	NameRegexp = expression(
		optional(DomainRegexp, literal(`/`)),
		nameComponentRegexp,
		optional(repeated(literal(`/`), nameComponentRegexp)))

	// ReferenceRegexp is the full supported format of a reference. The regexp
	// is anchored and has capturing groups for name, tag, and digest
	// components.
	ReferenceRegexp = anchored(capture(NameRegexp),
		optional(literal(":"), capture(TagRegexp)),
		optional(literal("@"), capture(DigestRegexp)))

	// 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.
	IdentifierRegexp = match(`([a-f0-9]{64})`)

	// ShortIdentifierRegexp is the format used to represent a prefix
	// of an identifier. A prefix may be used to match a sha256 identifier
	// within a list of trusted identifiers.
	ShortIdentifierRegexp = match(`([a-f0-9]{6,64})`)
)

var Settings = &settings.Settings