support topic wildcard

event_bus.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"reflect"
 	"sync"
+
+	"github.com/bcw104/EventBus/wildcard"
 )
 
 //BusSubscriber defines subscription-related bus behavior
@@ -45,7 +47,7 @@ type eventHandler struct {
 	flagOnce      bool
 	async         bool
 	transactional bool
-	sync.Mutex // lock for an event handler - useful for running async callbacks serially
+	sync.Mutex    // lock for an event handler - useful for running async callbacks serially
 }
 
 // New returns new EventBus with empty handlers.
@@ -131,23 +133,25 @@ func (bus *EventBus) Unsubscribe(topic string, handler interface{}) error {
 func (bus *EventBus) Publish(topic string, args ...interface{}) {
 	bus.lock.Lock() // will unlock if handler is not found or always after setUpPublish
 	defer bus.lock.Unlock()
-	if handlers, ok := bus.handlers[topic]; ok && 0 < len(handlers) {
-		// Handlers slice may be changed by removeHandler and Unsubscribe during iteration,
-		// so make a copy and iterate the copied slice.
-		copyHandlers := make([]*eventHandler, 0, len(handlers))
-		copyHandlers = append(copyHandlers, handlers...)
-		for i, handler := range copyHandlers {
-			if handler.flagOnce {
-				bus.removeHandler(topic, i)
-			}
-			if !handler.async {
-				bus.doPublish(handler, topic, args...)
-			} else {
-				bus.wg.Add(1)
-				if handler.transactional {
-					handler.Lock()
+	for topicPattern, handlers := range bus.handlers {
+		if 0 < len(handlers) && wildcard.MatchSimple(topicPattern, topic) {
+			// Handlers slice may be changed by removeHandler and Unsubscribe during iteration,
+			// so make a copy and iterate the copied slice.
+			copyHandlers := make([]*eventHandler, 0, len(handlers))
+			copyHandlers = append(copyHandlers, handlers...)
+			for i, handler := range copyHandlers {
+				if handler.flagOnce {
+					bus.removeHandler(topic, i)
+				}
+				if !handler.async {
+					bus.doPublish(handler, topic, args...)
+				} else {
+					bus.wg.Add(1)
+					if handler.transactional {
+						handler.Lock()
+					}
+					go bus.doPublishAsync(handler, topic, args...)
 				}
-				go bus.doPublishAsync(handler, topic, args...)
 			}
 		}
 	}

wildcard/match.go

@@ -0,0 +1,67 @@
+package wildcard
+
+// MatchSimple - finds whether the text matches/satisfies the pattern string.
+// supports only '*' wildcard in the pattern.
+// considers a file system path as a flat name space.
+func MatchSimple(pattern, name string) bool {
+	if pattern == "" {
+		return name == pattern
+	}
+	if pattern == "*" {
+		return true
+	}
+	rname := make([]rune, 0, len(name))
+	rpattern := make([]rune, 0, len(pattern))
+	for _, r := range name {
+		rname = append(rname, r)
+	}
+	for _, r := range pattern {
+		rpattern = append(rpattern, r)
+	}
+	simple := true // Does only wildcard '*' match.
+	return deepMatchRune(rname, rpattern, simple)
+}
+
+// Match -  finds whether the text matches/satisfies the pattern string.
+// supports  '*' and '?' wildcards in the pattern string.
+// unlike path.Match(), considers a path as a flat name space while matching the pattern.
+// The difference is illustrated in the example here https://play.golang.org/p/Ega9qgD4Qz .
+func Match(pattern, name string) (matched bool) {
+	if pattern == "" {
+		return name == pattern
+	}
+	if pattern == "*" {
+		return true
+	}
+	rname := make([]rune, 0, len(name))
+	rpattern := make([]rune, 0, len(pattern))
+	for _, r := range name {
+		rname = append(rname, r)
+	}
+	for _, r := range pattern {
+		rpattern = append(rpattern, r)
+	}
+	simple := false // Does extended wildcard '*' and '?' match.
+	return deepMatchRune(rname, rpattern, simple)
+}
+
+func deepMatchRune(str, pattern []rune, simple bool) bool {
+	for len(pattern) > 0 {
+		switch pattern[0] {
+		default:
+			if len(str) == 0 || str[0] != pattern[0] {
+				return false
+			}
+		case '?':
+			if len(str) == 0 && !simple {
+				return false
+			}
+		case '*':
+			return deepMatchRune(str, pattern[1:], simple) ||
+				(len(str) > 0 && deepMatchRune(str[1:], pattern, simple))
+		}
+		str = str[1:]
+		pattern = pattern[1:]
+	}
+	return len(str) == 0 && len(pattern) == 0
+}