reference: make some regexp vars a const, remove intermediate vars
This patch: - makes regexp strings that are constant a const - moves some variables closer to where they're used - removes some intermediate vars - un-wraps some lines; they're lengthy, but probably more readable than having them wrapped over multiple lines. - touches-up some docs. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
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Sebastiaan van Stijn
parent
10eace9a53
commit
226b21beb6
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@ -2,13 +2,13 @@ package reference
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import "regexp"
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var (
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// alphaNumeric defines the alpha numeric atom, typically a
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const (
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// alphanumeric defines the alphanumeric atom, typically a
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// component of names. This only allows lower case characters and digits.
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alphaNumeric = `[a-z0-9]+`
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alphanumeric = `[a-z0-9]+`
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// separator defines the separators allowed to be embedded in name
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// components. This allow one period, one or two underscore and multiple
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// components. This allows one period, one or two underscore and multiple
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// dashes. Repeated dashes and underscores are intentionally treated
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// differently. In order to support valid hostnames as name components,
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// supporting repeated dash was added. Additionally double underscore is
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@ -16,33 +16,43 @@ var (
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// supported names.
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separator = `(?:[._]|__|[-]*)`
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// nameComponent restricts registry path component names to start
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// with at least one letter or number, with following parts able to be
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// separated by one period, one or two underscore and multiple dashes.
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nameComponent = expression(
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alphaNumeric,
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optional(repeated(separator, alphaNumeric)))
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// domainNameComponent restricts the registry domain component of a
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// repository name to start with a component as defined by DomainRegexp.
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domainNameComponent = `(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])`
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// tag matches valid tag names. From docker/docker:graph/tags.go.
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tag = `[\w][\w.-]{0,127}`
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// digestPat matches well-formed digests, including algorithm (e.g. "sha256:<encoded>").
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//
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// TODO(thaJeztah): this should follow the same rules as https://pkg.go.dev/github.com/opencontainers/go-digest@v1.0.0#DigestRegexp
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// so that go-digest defines the canonical format. Note that the go-digest is
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// more relaxed:
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// - it allows multiple algorithms (e.g. "sha256+b64:<encoded>") to allow
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// future expansion of supported algorithms.
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// - it allows the "<encoded>" value to use urlsafe base64 encoding as defined
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// in [rfc4648, section 5].
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//
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// [rfc4648, section 5]: https://www.rfc-editor.org/rfc/rfc4648#section-5.
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digestPat = `[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`
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// identifier is the format for a content addressable identifier using sha256.
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// These identifiers are like digests without the algorithm, since sha256 is used.
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identifier = `([a-f0-9]{64})`
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// ipv6address are enclosed between square brackets and may be represented
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// in many ways, see rfc5952. Only IPv6 in compressed or uncompressed format
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// are allowed, IPv6 zone identifiers (rfc6874) or Special addresses such as
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// IPv4-Mapped are deliberately excluded.
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ipv6address = expression(
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literal(`[`), `(?:[a-fA-F0-9:]+)`, literal(`]`),
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)
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ipv6address = `\[(?:[a-fA-F0-9:]+)\]`
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)
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var (
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// domainName defines the structure of potential domain components
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// that may be part of image names. This is purposely a subset of what is
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// allowed by DNS to ensure backwards compatibility with Docker image
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// names. This includes IPv4 addresses on decimal format.
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domainName = expression(
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domainNameComponent,
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optional(repeated(literal(`.`), domainNameComponent)),
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)
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domainName = expression(domainNameComponent, optional(repeated(literal(`.`), domainNameComponent)))
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// host defines the structure of potential domains based on the URI
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// Host subcomponent on rfc3986. It may be a subset of DNS domain name,
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@ -53,69 +63,63 @@ var (
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// allowed by the URI Host subcomponent on rfc3986 to ensure backwards
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// compatibility with Docker image names.
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domain = expression(
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host,
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optional(literal(`:`), `[0-9]+`))
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domain = expression(host, optional(literal(`:`), `[0-9]+`))
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// DomainRegexp defines the structure of potential domain components
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// that may be part of image names. This is purposely a subset of what is
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// allowed by DNS to ensure backwards compatibility with Docker image
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// names.
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// DomainRegexp matches hostname or IP-addresses, optionally including a port
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// number. It defines the structure of potential domain components that may be
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// part of image names. This is purposely a subset of what is allowed by DNS to
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// ensure backwards compatibility with Docker image names. It may be a subset of
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// DNS domain name, an IPv4 address in decimal format, or an IPv6 address between
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// square brackets (excluding zone identifiers as defined by [rfc6874] or special
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// addresses such as IPv4-Mapped).
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//
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// [rfc6874]: https://www.rfc-editor.org/rfc/rfc6874.
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DomainRegexp = regexp.MustCompile(domain)
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tag = `[\w][\w.-]{0,127}`
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// TagRegexp matches valid tag names. From docker/docker:graph/tags.go.
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TagRegexp = regexp.MustCompile(tag)
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anchoredTag = anchored(tag)
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// anchoredTagRegexp matches valid tag names, anchored at the start and
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// end of the matched string.
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anchoredTagRegexp = regexp.MustCompile(anchoredTag)
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anchoredTagRegexp = regexp.MustCompile(anchored(tag))
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digestPat = `[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`
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// DigestRegexp matches valid digests.
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// DigestRegexp matches well-formed digests, including algorithm (e.g. "sha256:<encoded>").
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DigestRegexp = regexp.MustCompile(digestPat)
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anchoredDigest = anchored(digestPat)
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// anchoredDigestRegexp matches valid digests, anchored at the start and
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// end of the matched string.
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anchoredDigestRegexp = regexp.MustCompile(anchoredDigest)
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anchoredDigestRegexp = regexp.MustCompile(anchored(digestPat))
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// nameComponent restricts registry path component names to start
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// with at least one letter or number, with following parts able to be
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// separated by one period, one or two underscore and multiple dashes.
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nameComponent = expression(alphanumeric, optional(repeated(separator, alphanumeric)))
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namePat = expression(optional(domain, literal(`/`)), nameComponent, optional(repeated(literal(`/`), nameComponent)))
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namePat = expression(
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optional(domain, literal(`/`)),
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nameComponent,
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optional(repeated(literal(`/`), nameComponent)))
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// NameRegexp is the format for the name component of references. The
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// regexp has capturing groups for the domain and name part omitting
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// the separating forward slash from either.
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NameRegexp = regexp.MustCompile(namePat)
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anchoredName = anchored(
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optional(capture(domain), literal(`/`)),
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capture(nameComponent,
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optional(repeated(literal(`/`), nameComponent))))
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// anchoredNameRegexp is used to parse a name value, capturing the
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// domain and trailing components.
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anchoredNameRegexp = regexp.MustCompile(anchoredName)
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anchoredNameRegexp = regexp.MustCompile(anchored(optional(capture(domain), literal(`/`)), capture(nameComponent, optional(repeated(literal(`/`), nameComponent)))))
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referencePat = anchored(capture(namePat), optional(literal(":"), capture(tag)), optional(literal("@"), capture(digestPat)))
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referencePat = anchored(capture(namePat),
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optional(literal(":"), capture(tag)),
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optional(literal("@"), capture(digestPat)))
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// ReferenceRegexp is the full supported format of a reference. The regexp
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// is anchored and has capturing groups for name, tag, and digest
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// components.
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ReferenceRegexp = regexp.MustCompile(referencePat)
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identifier = `([a-f0-9]{64})`
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// IdentifierRegexp is the format for string identifier used as a
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// content addressable identifier using sha256. These identifiers
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// are like digests without the algorithm, since sha256 is used.
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IdentifierRegexp = regexp.MustCompile(identifier)
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anchoredIdentifier = anchored(identifier)
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// anchoredIdentifierRegexp is used to check or match an
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// identifier value, anchored at start and end of string.
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anchoredIdentifierRegexp = regexp.MustCompile(anchoredIdentifier)
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anchoredIdentifierRegexp = regexp.MustCompile(anchored(identifier))
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)
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// literal compiles s into a literal regular expression, escaping any regexp
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