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regexp.go
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regexp.go
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package reference
import "regexp"
//
// v1 org.opencontainers.image.ref.name:
//
// NOTE: extend separator with "__" here to compatibility with moby
//
// ref ::= component ("/" component)*
// component ::= alphanum (separator alphanum)*
// alphanum ::= [A-Za-z0-9]+
// separator ::= [-._:@+] | "--" | "__"
//
// In the image-spec, there is no definition about Tag.
//
// But, in fact, the Tag looks like:
//
// :\w[\w.-]*$
//
var (
regAlphanum = expression(`[A-Za-z0-9]`)
regSeparator = expression(`([-._:@+]|--|__)`)
regComponent = group(
oneOrMore(regAlphanum),
zeroOrMore(regSeparator, oneOrMore(regAlphanum)))
regRef = entire(
regComponent,
zeroOrMore(expression("/"), regComponent))
regTag = expression(`:\w[\w.-]*$`)
regDigest = expression(`@[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`)
)
// expression converts literal into regexp.
func expression(literal string) *regexp.Regexp {
return regexp.MustCompile(literal)
}
// concat concats several expressions into one.
func concat(exp ...*regexp.Regexp) *regexp.Regexp {
s := ""
for i := range exp {
s = s + exp[i].String()
}
return regexp.MustCompile(s)
}
// entire will match the whole line.
func entire(exp ...*regexp.Regexp) *regexp.Regexp {
return regexp.MustCompile("^" + concat(exp...).String() + "$")
}
// zeroOrMore will group the expressions and match zero or more times.
func zeroOrMore(exp ...*regexp.Regexp) *regexp.Regexp {
return regexp.MustCompile(group(concat(exp...)).String() + "*")
}
// zeroOrMore will group the expressions and match one or more times.
func oneOrMore(exp ...*regexp.Regexp) *regexp.Regexp {
return regexp.MustCompile(group(concat(exp...)).String() + "+")
}
// group defines sub expression.
func group(exp ...*regexp.Regexp) *regexp.Regexp {
return regexp.MustCompile("(?:" + concat(exp...).String() + ")")
}