v1.0.0

common/strmatcher/strmatcher.go

@@ -0,0 +1,106 @@
+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) {
+	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 &regexMatcher{
+			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
+}