Do not use defer for unlocking in Scratch

It is a fairly costly operation:

```
benchmark                 old ns/op     new ns/op     delta
BenchmarkScratchGet-4     109           31.6          -71.01%

benchmark                 old allocs     new allocs     delta
BenchmarkScratchGet-4     0              0              +0.00%

benchmark                 old bytes     new bytes     delta
BenchmarkScratchGet-4     0             0             +0.00%
´´´
This commit is contained in:
Bjørn Erik Pedersen 2016-03-24 15:33:25 +01:00
parent fa1a9653e5
commit c846b051f3

View file

@ -31,11 +31,11 @@ type Scratch struct {
//
// If the first add for a key is an array or slice, then the next value(s) will be appended.
func (c *Scratch) Add(key string, newAddend interface{}) (string, error) {
c.mu.Lock()
defer c.mu.Unlock()
var newVal interface{}
c.mu.RLock()
existingAddend, found := c.values[key]
c.mu.RUnlock()
if found {
var err error
@ -57,7 +57,9 @@ func (c *Scratch) Add(key string, newAddend interface{}) (string, error) {
} else {
newVal = newAddend
}
c.mu.Lock()
c.values[key] = newVal
c.mu.Unlock()
return "", nil // have to return something to make it work with the Go templates
}
@ -65,46 +67,45 @@ func (c *Scratch) Add(key string, newAddend interface{}) (string, error) {
// This value can later be retrieved with Get.
func (c *Scratch) Set(key string, value interface{}) string {
c.mu.Lock()
defer c.mu.Unlock()
c.values[key] = value
c.mu.Unlock()
return ""
}
// Get returns a value previously set by Add or Set
func (c *Scratch) Get(key string) interface{} {
c.mu.RLock()
defer c.mu.RUnlock()
val := c.values[key]
c.mu.RUnlock()
return c.values[key]
return val
}
// SetInMap stores a value to a map with the given key in the Node context.
// This map can later be retrieved with GetSortedMapValues.
func (c *Scratch) SetInMap(key string, mapKey string, value interface{}) string {
c.mu.Lock()
defer c.mu.Unlock()
_, found := c.values[key]
if !found {
c.values[key] = make(map[string]interface{})
}
c.values[key].(map[string]interface{})[mapKey] = value
c.mu.Unlock()
return ""
}
// GetSortedMapValues returns a sorted map previously filled with SetInMap
func (c *Scratch) GetSortedMapValues(key string) interface{} {
c.mu.RLock()
defer c.mu.RUnlock()
if c.values[key] == nil {
c.mu.RUnlock()
return nil
}
unsortedMap := c.values[key].(map[string]interface{})
c.mu.RUnlock()
var keys []string
for mapKey := range unsortedMap {
keys = append(keys, mapKey)