Initial

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/github.com/docker/distribution/reference/regexp.go

@@ -0,0 +1,143 @@
+package reference
+
+import "regexp"
+
+var (
+	// alphaNumericRegexp defines the alpha numeric atom, typically a
+	// component of names. This only allows lower case characters and digits.
+	alphaNumericRegexp = match(`[a-z0-9]+`)
+
+	// separatorRegexp defines the separators allowed to be embedded in name
+	// components. This allow one period, one or two underscore and multiple
+	// dashes.
+	separatorRegexp = match(`(?:[._]|__|[-]*)`)
+
+	// nameComponentRegexp restricts registry path component names to start
+	// with at least one letter or number, with following parts able to be
+	// separated by one period, one or two underscore and multiple dashes.
+	nameComponentRegexp = expression(
+		alphaNumericRegexp,
+		optional(repeated(separatorRegexp, alphaNumericRegexp)))
+
+	// domainComponentRegexp restricts the registry domain component of a
+	// repository name to start with a component as defined by DomainRegexp
+	// and followed by an optional port.
+	domainComponentRegexp = match(`(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])`)
+
+	// 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}`)
+
+	// anchoredTagRegexp matches valid tag names, anchored at the start and
+	// end of the matched string.
+	anchoredTagRegexp = anchored(TagRegexp)
+
+	// DigestRegexp matches valid digests.
+	DigestRegexp = match(`[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`)
+
+	// anchoredDigestRegexp matches valid digests, anchored at the start and
+	// end of the matched string.
+	anchoredDigestRegexp = anchored(DigestRegexp)
+
+	// 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)))
+
+	// anchoredNameRegexp is used to parse a name value, capturing the
+	// domain and trailing components.
+	anchoredNameRegexp = anchored(
+		optional(capture(DomainRegexp), literal(`/`)),
+		capture(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})`)
+
+	// anchoredIdentifierRegexp is used to check or match an
+	// identifier value, anchored at start and end of string.
+	anchoredIdentifierRegexp = anchored(IdentifierRegexp)
+
+	// anchoredShortIdentifierRegexp is used to check if a value
+	// is a possible identifier prefix, anchored at start and end
+	// of string.
+	anchoredShortIdentifierRegexp = anchored(ShortIdentifierRegexp)
+)
+
+// match compiles the string to a regular expression.
+var match = regexp.MustCompile
+
+// literal compiles s into a literal regular expression, escaping any regexp
+// reserved characters.
+func literal(s string) *regexp.Regexp {
+	re := match(regexp.QuoteMeta(s))
+
+	if _, complete := re.LiteralPrefix(); !complete {
+		panic("must be a literal")
+	}
+
+	return re
+}
+
+// expression defines a full expression, where each regular expression must
+// follow the previous.
+func expression(res ...*regexp.Regexp) *regexp.Regexp {
+	var s string
+	for _, re := range res {
+		s += re.String()
+	}
+
+	return match(s)
+}
+
+// optional wraps the expression in a non-capturing group and makes the
+// production optional.
+func optional(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(group(expression(res...)).String() + `?`)
+}
+
+// repeated wraps the regexp in a non-capturing group to get one or more
+// matches.
+func repeated(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(group(expression(res...)).String() + `+`)
+}
+
+// group wraps the regexp in a non-capturing group.
+func group(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(`(?:` + expression(res...).String() + `)`)
+}
+
+// capture wraps the expression in a capturing group.
+func capture(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(`(` + expression(res...).String() + `)`)
+}
+
+// anchored anchors the regular expression by adding start and end delimiters.
+func anchored(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(`^` + expression(res...).String() + `$`)
+}