增加policy缓存，降低日志量和计算量

pkg/util/hashcache/cache.go

@@ -0,0 +1,103 @@
+package hashcache
+
+import (
+	"crypto/md5"
+	"crypto/sha1"
+	"crypto/sha256"
+	"sync"
+	"time"
+)
+
+type cacheNode struct {
+	key    string
+	expire time.Time
+	value  interface{}
+}
+
+type Cache struct {
+	table      []cacheNode
+	lock       *sync.Mutex
+	size       uint32
+	defaultTtl time.Duration
+}
+
+func NewCache(size uint32, defaultTTL time.Duration) *Cache {
+	ca := &Cache{table: make([]cacheNode, size), lock: &sync.Mutex{}, size: size, defaultTtl: defaultTTL}
+	return ca
+}
+
+const (
+	HASH_ALG_MD5    int = iota
+	HASH_ALG_SHA1
+	HASH_ALG_SHA256
+)
+
+func bytes2int(b []byte) uint32 {
+	return ((uint32(b[0]) << 24) | (uint32(b[1]) << 16) | (uint32(b[2]) << 8) | (uint32(b[3])))
+}
+
+func checksum(alg int, key string) uint32 {
+	var hash uint32 = 0
+	switch alg {
+	case HASH_ALG_MD5:
+		v := md5.Sum([]byte(key))
+		hash = bytes2int(v[0:4])
+	case HASH_ALG_SHA1:
+		v := sha1.Sum([]byte(key))
+		hash = bytes2int(v[0:4])
+	case HASH_ALG_SHA256:
+		v := sha256.Sum224([]byte(key))
+		hash = bytes2int(v[0:4])
+	}
+	return hash
+}
+
+func (c *Cache) find(key string) (bool, uint32) {
+	var idx uint32
+	now := time.Now()
+	for _, alg := range []int{HASH_ALG_MD5, HASH_ALG_SHA1, HASH_ALG_SHA256} {
+		idx = checksum(alg, key) % c.size
+		if c.table[idx].key == key {
+			if c.table[idx].expire.IsZero() || c.table[idx].expire.After(now) {
+				return true, idx
+			}
+			break
+		}
+	}
+	return false, idx
+}
+
+func (c *Cache) Get(key string) interface{} {
+	find, idx := c.find(key)
+	if find {
+		return c.table[idx].value
+	}
+	return nil
+}
+
+func (c *Cache) AtomicGet(key string) interface{} {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	return c.Get(key)
+}
+
+func (c *Cache) Set(key string, val interface{}, expire ...time.Time) {
+	find, idx := c.find(key)
+	if !find {
+		c.table[idx].key = key
+	}
+	c.table[idx].value = val
+	if len(expire) > 0 && ! expire[0].IsZero() {
+		c.table[idx].expire = expire[0]
+	} else if c.defaultTtl > time.Millisecond {
+		c.table[idx].expire = time.Now().Add(c.defaultTtl)
+	} else {
+		c.table[idx].expire = time.Time{}
+	}
+}
+
+func (c *Cache) AtomicSet(key string, val interface{}) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.Set(key, val)
+}