// CheckAndSet put a value with a key into the Cache,
// ONLY IF it has no newer values with, i.e. no update since, a given serial.
// It takes key, value parameters as an interface{} type and performs marshal for them.
// If succeed, it returns a serial number(an unix timestamp in millis) for the value.
// If a value of newer serial already exists, CheckAndSet would fail with ErrSetFailed.
func (c *Cache) CheckAndSet(key interface{}, val interface{}, oserial int64) (int64, error) {
bkey, err := c.options.Marshal(key)
if err != nil {
return 0, err
}
client, disconnect, _, err := c.connector.Connect(bkey)
if err != nil {
return 0, err
}
defer func() {
if disconnect != nil {
disconnect()
}
}()
bval, err := c.options.Marshal(val)
if err != nil {
return 0, err
}
nserial := getSerial()
resp := util.LuaEval(client, luaForCheckAndSet, 1, bkey, bval, oserial, nserial, c.options.Expiration.Seconds())
if resp.Err != nil {
return 0, resp.Err
}
if resp.IsType(redis.Nil) {
return 0, ErrSetFailed
}
atomic.AddInt64(&c.loads, 1)
return nserial, nil
}
// Get returns a cached value using bound Connector.
// It takes key, value parameters as an interface{} type and performs marshal/unmarshal for them.
func (c *Cache) Get(key interface{}, val interface{}) (int64, error) {
bkey, err := c.options.Marshal(key)
if err != nil {
return 0, err
}
client, disconnect, validSince, err := c.connector.Connect(bkey)
if err != nil {
return 0, err
}
defer func() {
if disconnect != nil {
disconnect()
}
}()
resp := util.LuaEval(client, luaForGet, 1, bkey, validSince)
if resp.Err != nil {
return 0, resp.Err
}
if resp.IsType(redis.Nil) {
atomic.AddInt64(&c.misses, 1)
return 0, ErrNoKey
}
if resp.IsType(redis.Array) {
if res, err := resp.Array(); err == nil && len(res) == 2 {
if res[0].IsType(redis.BulkStr) && res[1].IsType(redis.Int) {
bval, _ := res[0].Bytes()
serial, _ := res[1].Int64()
if err := c.options.Unmarshal(bval, val); err != nil {
return 0, err
}
atomic.AddInt64(&c.hits, 1)
return serial, nil
}
}
}
return 0, ErrRESPParse
}