package strmatcher import ( "regexp" ) // Matcher is the interface to determine a string matches a pattern. type Matcher interface { // Match returns true if the given string matches a predefined pattern. Match(string) bool String() string } // Type is the type of the matcher. type Type byte const ( // Full is the type of matcher that the input string must exactly equal to the pattern. Full Type = iota // Substr is the type of matcher that the input string must contain the pattern as a sub-string. Substr // Domain is the type of matcher that the input string must be a sub-domain or itself of the pattern. Domain // Regex is the type of matcher that the input string must matches the regular-expression pattern. Regex ) // New creates a new Matcher based on the given pattern. func (t Type) New(pattern string) (Matcher, error) { // 1. regex matching is case-sensitive switch t { case Full: return fullMatcher(pattern), nil case Substr: return substrMatcher(pattern), nil case Domain: return domainMatcher(pattern), nil case Regex: r, err := regexp.Compile(pattern) if err != nil { return nil, err } return ®exMatcher{ pattern: r, }, nil default: panic("Unknown type") } } // IndexMatcher is the interface for matching with a group of matchers. type IndexMatcher interface { // Match returns the index of a matcher that matches the input. It returns empty array if no such matcher exists. Match(input string) []uint32 } type matcherEntry struct { m Matcher id uint32 } // MatcherGroup is an implementation of IndexMatcher. // Empty initialization works. type MatcherGroup struct { count uint32 fullMatcher FullMatcherGroup domainMatcher DomainMatcherGroup otherMatchers []matcherEntry } // Add adds a new Matcher into the MatcherGroup, and returns its index. The index will never be 0. func (g *MatcherGroup) Add(m Matcher) uint32 { g.count++ c := g.count switch tm := m.(type) { case fullMatcher: g.fullMatcher.addMatcher(tm, c) case domainMatcher: g.domainMatcher.addMatcher(tm, c) default: g.otherMatchers = append(g.otherMatchers, matcherEntry{ m: m, id: c, }) } return c } // Match implements IndexMatcher.Match. func (g *MatcherGroup) Match(pattern string) []uint32 { result := []uint32{} result = append(result, g.fullMatcher.Match(pattern)...) result = append(result, g.domainMatcher.Match(pattern)...) for _, e := range g.otherMatchers { if e.m.Match(pattern) { result = append(result, e.id) } } return result } // Size returns the number of matchers in the MatcherGroup. func (g *MatcherGroup) Size() uint32 { return g.count }