Improved Cache Stability With Concurrency

Author: AspieSoft

regex.go

@@ -5,6 +5,7 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/GRbit/go-pcre"
 )
@@ -59,6 +60,38 @@ func JoinBytes(bytes ...interface{}) []byte {
 	return res
 }
 
+var writingCache int = 0
+
+func setCache(re string, reg pcre.Regexp){
+	for writingCache != 0 {
+		time.Sleep(1000)
+	}
+
+	writingCache++
+
+	if writingCache != 1 {
+		writingCache--
+		go setCache(re, reg)
+		return
+	}
+
+	regCache[re] = reg
+
+	writingCache--
+}
+
+func getCache(re string) (pcre.Regexp, bool) {
+	if writingCache != 0 {
+		return pcre.Regexp{}, false
+	}
+	
+	if val, ok := regCache[re]; ok {
+		return val, true
+	}
+
+	return pcre.Regexp{}, false
+}
+
 func Compile(re string) Regexp {
 	if strings.Contains(re, `\'`) {
 		r := []byte(re)
@@ -79,12 +112,13 @@ func Compile(re string) Regexp {
 		re = regReReplaceComment.ReplaceAllString(re, ``, 0)
 	}
 
-	if val, ok := regCache[re]; ok {
+	if val, ok := getCache(re); ok {
 		return val
 	} else {
 		// reg := pcre.MustCompileJIT(re, pcre.UTF8, pcre.CONFIG_JIT)
 		reg := pcre.MustCompile(re, pcre.UTF8)
-		regCache[re] = reg
+		// regCache[re] = reg
+		go setCache(re, reg)
 		return reg
 	}
 }

regex_test.go

@@ -3,7 +3,9 @@ package regex
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"testing"
+	"time"
 )
 
 func TestCompile(t *testing.T) {
@@ -29,3 +31,15 @@ func TestReplace(t *testing.T) {
 	check("string with `block` quotes", `\'.*?\'`, "'single'", "string with 'single' quotes")
 }
 
+func TestConcurent(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		go (func(){
+			res := RepFunc([]byte("test"), `(t)`, func(data func(int) []byte) []byte {
+				return data(1)
+			})
+			fmt.Println(string(res))
+		})()
+	}
+
+	time.Sleep(1000000 * 1000) // 1 second
+}