Fixes race in getKeyMetadata accessor, when called from KeyMetadata (#233)

Author: cognusion

bigcache.go

@@ -193,7 +193,7 @@ func (c *BigCache) Stats() Stats {
 func (c *BigCache) KeyMetadata(key string) Metadata {
 	hashedKey := c.hash.Sum64(key)
 	shard := c.getShard(hashedKey)
-	return shard.getKeyMetadata(hashedKey)
+	return shard.getKeyMetadataWithLock(hashedKey)
 }
 
 // Iterator returns iterator function to iterate over EntryInfo's from whole cache.

shard.go

@@ -341,6 +341,15 @@ func (s *cacheShard) getStats() Stats {
 	return stats
 }
 
+func (s *cacheShard) getKeyMetadataWithLock(key uint64) Metadata {
+	s.lock.RLock()
+	c := s.hashmapStats[key]
+	s.lock.RUnlock()
+	return Metadata{
+		RequestCount: c,
+	}
+}
+
 func (s *cacheShard) getKeyMetadata(key uint64) Metadata {
 	return Metadata{
 		RequestCount: s.hashmapStats[key],