代码生成

base/utils/regexp.go

@@ -0,0 +1,44 @@
+package utils
+
+import (
+	"pandax/base/global"
+	"regexp"
+	"sync"
+)
+
+var (
+	regexMu = sync.RWMutex{}
+	// Cache for regex object.
+	// Note that:
+	// 1. It uses sync.RWMutex ensuring the concurrent safety.
+	// 2. There's no expiring logic for this map.
+	regexMap = make(map[string]*regexp.Regexp)
+)
+
+// getRegexp returns *regexp.Regexp object with given `pattern`.
+// It uses cache to enhance the performance for compiling regular expression pattern,
+// which means, it will return the same *regexp.Regexp object with the same regular
+// expression pattern.
+//
+// It is concurrent-safe for multiple goroutines.
+func GetRegexp(pattern string) (regex *regexp.Regexp, err error) {
+	// Retrieve the regular expression object using reading lock.
+	regexMu.RLock()
+	regex = regexMap[pattern]
+	regexMu.RUnlock()
+	if regex != nil {
+		return
+	}
+	// If it does not exist in the cache,
+	// it compiles the pattern and creates one.
+	regex, err = regexp.Compile(pattern)
+	if err != nil {
+		global.Log.Warnf(`regexp.Compile failed for pattern "%s"`, pattern)
+		return
+	}
+	// Cache the result object using writing lock.
+	regexMu.Lock()
+	regexMap[pattern] = regex
+	regexMu.Unlock()
+	return
+}