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Add/Replace atomicity for r60.3

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This commit is contained in:
Patrick Mylund Nielsen 2012-01-04 09:09:39 +01:00
parent e6e2a3d192
commit 62a061f1f4
2 changed files with 36 additions and 26 deletions
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41
cache.go
View File

@ -2,6 +2,7 @@ package cache
import (
"fmt"
"os"
"reflect"
"runtime"
"sync"
@ -91,7 +92,7 @@ type Cache struct {
}
type cache struct {
DefaultExpiration time.Duration
DefaultExpiration int64
Items map[string]*Item
mu *sync.Mutex
janitor *janitor
@ -99,30 +100,30 @@ type cache struct {
type Item struct {
Object interface{}
Expiration *time.Time
Expiration *int64
}
type janitor struct {
Interval time.Duration
Interval int64
stop chan bool
}
// Adds an item to the cache, replacing any existing item. If the duration is 0, the
// cache's default expiration time is used. If it is -1, the item never expires.
func (c *cache) Set(k string, x interface{}, d time.Duration) {
func (c *cache) Set(k string, x interface{}, d int64) {
c.mu.Lock()
defer c.mu.Unlock()
c.set(k, x, d)
}
func (c *cache) set(k string, x interface{}, d time.Duration) {
var e *time.Time
func (c *cache) set(k string, x interface{}, d int64) {
var e *int64
if d == 0 {
d = c.DefaultExpiration
}
if d > 0 {
t := time.Now().Add(d)
t := time.Nanoseconds() + d
e = &t
}
c.Items[k] = &Item{
@ -132,8 +133,8 @@ func (c *cache) set(k string, x interface{}, d time.Duration) {
}
// Adds an item to the cache only if an item doesn't already exist for the given key,
// or if the existing item has expired. Returns an error if not.
func (c *cache) Add(k string, x interface{}, d time.Duration) error {
// or if the existing item has expired. Returns an os.Error if not.
func (c *cache) Add(k string, x interface{}, d int64) os.Error {
c.mu.Lock()
defer c.mu.Unlock()
@ -145,9 +146,9 @@ func (c *cache) Add(k string, x interface{}, d time.Duration) error {
return nil
}
// Sets a new value for the cache item only if it already exists. Returns an error if
// Sets a new value for the cache item only if it already exists. Returns an os.Error if
// it does not.
func (c *cache) Replace(k string, x interface{}, d time.Duration) error {
func (c *cache) Replace(k string, x interface{}, d int64) os.Error {
c.mu.Lock()
defer c.mu.Unlock()
@ -181,10 +182,10 @@ func (c *cache) get(k string) (interface{}, bool) {
}
// Increment an item of type int, int8, int16, int32, int64, uintptr, uint, uint8,
// uint32, uint64, float32 or float64 by n. Returns an error if the item's value is
// uint32, uint64, float32 or float64 by n. Returns an os.Error if the item's value is
// not an integer, if it was not found, or if it is not possible to increment it by
// n. Passing a negative number will cause the item to be decremented.
func (c *cache) IncrementFloat(k string, n float64) error {
func (c *cache) IncrementFloat(k string, n float64) os.Error {
c.mu.Lock()
defer c.mu.Unlock()
@ -228,18 +229,18 @@ func (c *cache) IncrementFloat(k string, n float64) error {
}
// Increment an item of type int, int8, int16, int32, int64, uintptr, uint, uint8,
// uint32, or uint64, float32 or float64 by n. Returns an error if the item's value
// uint32, or uint64, float32 or float64 by n. Returns an os.Error if the item's value
// is not an integer, if it was not found, or if it is not possible to increment it
// by n. Passing a negative number will cause the item to be decremented.
func (c *cache) Increment(k string, n int64) error {
func (c *cache) Increment(k string, n int64) os.Error {
return c.IncrementFloat(k, float64(n))
}
// Decrement an item of type int, int8, int16, int32, int64, uintptr, uint, uint8,
// uint32, or uint64, float32 or float64 by n. Returns an error if the item's value
// uint32, or uint64, float32 or float64 by n. Returns an os.Error if the item's value
// is not an integer, if it was not found, or if it is not possible to decrement it
// by n.
func (c *cache) Decrement(k string, n int64) error {
func (c *cache) Decrement(k string, n int64) os.Error {
return c.Increment(k, n*-1)
}
@ -252,7 +253,7 @@ func (c *cache) Delete(k string) {
}
func (c *cache) delete(k string) {
delete(c.Items, k)
c.Items[k] = nil, false
}
// Deletes all expired items from the cache.
@ -280,7 +281,7 @@ func (i *Item) Expired() bool {
if i.Expiration == nil {
return false
}
return i.Expiration.Before(time.Now())
return *i.Expiration < time.Nanoseconds()
}
func (j *janitor) Run(c *cache) {
@ -309,7 +310,7 @@ func stopJanitor(c *Cache) {
// expire and must be deleted manually. If the cleanup interval is less than one,
// expired items are not deleted from the cache before their next lookup or before
// calling DeleteExpired.
func New(de, ci time.Duration) *Cache {
func New(de, ci int64) *Cache {
if de == 0 {
de = -1
}

21
cache_test.go
View File

@ -5,6 +5,15 @@ import (
"time"
)
const (
Nanosecond = 1
Microsecond = 1000 * Nanosecond
Millisecond = 1000 * Microsecond
Second = 1000 * Millisecond
Minute = 60 * Second
Hour = 60 * Minute
)
func TestCache(t *testing.T) {
tc := New(0, 0)
@ -61,19 +70,19 @@ func TestCache(t *testing.T) {
func TestCacheTimes(t *testing.T) {
var found bool
tc := New(50*time.Millisecond, 1*time.Millisecond)
tc := New(50*Millisecond, 1*Millisecond)
tc.Set("a", 1, 0)
tc.Set("b", 2, -1)
tc.Set("c", 3, 20*time.Millisecond)
tc.Set("d", 4, 70*time.Millisecond)
tc.Set("c", 3, 20*Millisecond)
tc.Set("d", 4, 70*Millisecond)
<-time.After(25 * time.Millisecond)
<-time.After(25 * Millisecond)
_, found = tc.Get("c")
if found {
t.Error("Found c when it should have been automatically deleted")
}
<-time.After(30 * time.Millisecond)
<-time.After(30 * Millisecond)
_, found = tc.Get("a")
if found {
t.Error("Found a when it should have been automatically deleted")
@ -89,7 +98,7 @@ func TestCacheTimes(t *testing.T) {
t.Error("Did not find d even though it was set to expire later than the default")
}
<-time.After(20 * time.Millisecond)
<-time.After(20 * Millisecond)
_, found = tc.Get("d")
if found {
t.Error("Found d when it should have been automatically deleted (later than the default)")