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Add namespace for Item and inline janitor 

Signed-off-by: Peng Gao <peng.gao.dut@gmail.com>
This commit is contained in:
Peng Gao 2016-09-01 14:03:22 +08:00
parent f26e1d0b06
commit 884405c431
4 changed files with 141 additions and 176 deletions
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151
cache.go
View File

@ -22,34 +22,34 @@ type Attr_tpl struct {
}
// Item struct
type Item struct {
type Item_tpl struct {
Object ValueType_tpl
Expiration int64
}
// Expired returns true if the item has expired.
func (item Item) Expired() bool {
func (item Item_tpl) Expired() bool {
return item.Expiration != 0 && time.Now().UnixNano() > item.Expiration
}
// Cache struct
type Cache_tpl struct {
*cache
*cache_tpl
// If this is confusing, see the comment at the bottom of New()
}
type cache struct {
type cache_tpl struct {
defaultExpiration time.Duration
items map[string]Item
items map[string]Item_tpl
mu sync.RWMutex
onEvicted func(string, ValueType_tpl)
janitor *janitor
stop chan bool
}
// Add an item to the cache, replacing any existing item. If the duration is 0
// (DefaultExpiration), the cache's default expiration time is used. If it is -1
// (NoExpiration), the item never expires.
func (c *cache) Set(k string, x ValueType_tpl, d time.Duration) {
func (c *cache_tpl) Set(k string, x ValueType_tpl, d time.Duration) {
// "Inlining" of set
var e int64
if d == DefaultExpiration {
@ -59,7 +59,7 @@ func (c *cache) Set(k string, x ValueType_tpl, d time.Duration) {
e = time.Now().Add(d).UnixNano()
}
c.mu.Lock()
c.items[k] = Item{
c.items[k] = Item_tpl{
Object: x,
Expiration: e,
}
@ -68,7 +68,7 @@ func (c *cache) Set(k string, x ValueType_tpl, d time.Duration) {
c.mu.Unlock()
}
func (c *cache) set(k string, x ValueType_tpl, d time.Duration) {
func (c *cache_tpl) set(k string, x ValueType_tpl, d time.Duration) {
var e int64
if d == DefaultExpiration {
d = c.defaultExpiration
@ -76,7 +76,7 @@ func (c *cache) set(k string, x ValueType_tpl, d time.Duration) {
if d > 0 {
e = time.Now().Add(d).UnixNano()
}
c.items[k] = Item{
c.items[k] = Item_tpl{
Object: x,
Expiration: e,
}
@ -84,7 +84,7 @@ func (c *cache) set(k string, x ValueType_tpl, d time.Duration) {
// Add 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 otherwise.
func (c *cache) Add(k string, x ValueType_tpl, d time.Duration) error {
func (c *cache_tpl) Add(k string, x ValueType_tpl, d time.Duration) error {
c.mu.Lock()
_, found := c.get(k)
if found {
@ -98,7 +98,7 @@ func (c *cache) Add(k string, x ValueType_tpl, d time.Duration) error {
// Set a new value for the cache key only if it already exists, and the existing
// item hasn't expired. Returns an error otherwise.
func (c *cache) Replace(k string, x ValueType_tpl, d time.Duration) error {
func (c *cache_tpl) Replace(k string, x ValueType_tpl, d time.Duration) error {
c.mu.Lock()
_, found := c.get(k)
if !found {
@ -112,7 +112,7 @@ func (c *cache) Replace(k string, x ValueType_tpl, d time.Duration) error {
// Get an item from the cache. Returns the item or nil, and a bool indicating
// whether the key was found.
func (c *cache) Get(k string) (ValueType_tpl, bool) {
func (c *cache_tpl) Get(k string) (ValueType_tpl, bool) {
c.mu.RLock()
// "Inlining" of get and Expired
item, found := c.items[k]
@ -125,7 +125,7 @@ func (c *cache) Get(k string) (ValueType_tpl, bool) {
return item.Object, true
}
func (c *cache) get(k string) (*ValueType_tpl, bool) {
func (c *cache_tpl) get(k string) (*ValueType_tpl, bool) {
item, found := c.items[k]
if !found || item.Expiration > 0 && time.Now().UnixNano() > item.Expiration {
return nil, false
@ -140,7 +140,7 @@ func (c *cache) get(k string) (*ValueType_tpl, bool) {
// item's value is not an integer, if it was not found, or if it is not
// possible to increment it by n. To retrieve the incremented value, use one
// of the specialized methods, e.g. IncrementInt64.
func (c *cache) Increment(k string, n ValueType_tpl) error {
func (c *cache_tpl) Increment(k string, n ValueType_tpl) error {
c.mu.Lock()
v, found := c.items[k]
if !found || v.Expired() {
@ -158,7 +158,7 @@ func (c *cache) Increment(k string, n ValueType_tpl) error {
// item's value is not an integer, if it was not found, or if it is not
// possible to decrement it by n. To retrieve the decremented value, use one
// of the specialized methods, e.g. DecrementInt64.
func (c *cache) Decrement(k string, n ValueType_tpl) error {
func (c *cache_tpl) Decrement(k string, n ValueType_tpl) error {
// TODO: Implement Increment and Decrement more cleanly.
// (Cannot do Increment(k, n*-1) for uints.)
c.mu.Lock()
@ -176,7 +176,7 @@ func (c *cache) Decrement(k string, n ValueType_tpl) error {
// MARK_Numberic_tpl_end
// Delete an item from the cache. Does nothing if the key is not in the cache.
func (c *cache) Delete(k string) {
func (c *cache_tpl) Delete(k string) {
// fast path
if c.onEvicted == nil {
c.mu.Lock()
@ -193,7 +193,7 @@ func (c *cache) Delete(k string) {
}
}
func (c *cache) delete(k string) (ValueType_tpl, bool) {
func (c *cache_tpl) delete(k string) (ValueType_tpl, bool) {
if v, found := c.items[k]; found {
delete(c.items, k)
return v.Object, true
@ -202,18 +202,16 @@ func (c *cache) delete(k string) (ValueType_tpl, bool) {
return 0, false
}
func (c *cache) deleteFast(k string) {
func (c *cache_tpl) deleteFast(k string) {
delete(c.items, k)
}
type keyAndValue struct {
key string
value ValueType_tpl
}
// Delete all expired items from the cache.
func (c *cache) DeleteExpired() {
var evictedItems []keyAndValue
func (c *cache_tpl) DeleteExpired() {
var evictedItems []struct {
key string
value ValueType_tpl
}
now := time.Now().UnixNano()
// fast path
if c.onEvicted == nil {
@ -234,7 +232,10 @@ func (c *cache) DeleteExpired() {
if v.Expiration > 0 && now > v.Expiration {
ov, evicted := c.delete(k)
if evicted {
evictedItems = append(evictedItems, keyAndValue{k, ov})
evictedItems = append(evictedItems, struct {
key string
value ValueType_tpl
}{k, ov})
}
}
}
@ -246,7 +247,7 @@ func (c *cache) DeleteExpired() {
// Returns the number of items in the cache. This may include items that have
// expired, but have not yet been cleaned up. Equivalent to len(c.Items()).
func (c *cache) ItemCount() int {
func (c *cache_tpl) ItemCount() int {
c.mu.RLock()
n := len(c.items)
c.mu.RUnlock()
@ -254,68 +255,32 @@ func (c *cache) ItemCount() int {
}
// Delete all items from the cache.
func (c *cache) Flush() {
func (c *cache_tpl) Flush() {
c.mu.Lock()
c.items = map[string]Item{}
c.items = map[string]Item_tpl{}
c.mu.Unlock()
}
type janitor struct {
Interval time.Duration
stop chan bool
// _ *cache_tpl is used as a namespace, so that "stopJanitor" will not conflicts for the name.
func (_ *cache_tpl) stopJanitor(c *Cache_tpl) {
c.stop <- true
}
func (j *janitor) Run(c *cache) {
j.stop = make(chan bool)
ticker := time.NewTicker(j.Interval)
for {
select {
case <-ticker.C:
c.DeleteExpired()
case <-j.stop:
ticker.Stop()
return
func (c *cache_tpl) runJanitor(ci time.Duration) {
c.stop = make(chan bool)
go func() {
ticker := time.NewTicker(ci)
for {
select {
case <-ticker.C:
c.DeleteExpired()
case <-c.stop:
ticker.Stop()
return
}
}
}
}
}()
func stopJanitor(c *Cache_tpl) {
c.janitor.stop <- true
}
func runJanitor(c *cache, ci time.Duration) {
j := &janitor{
Interval: ci,
}
c.janitor = j
go j.Run(c)
}
func newCache(de time.Duration, m map[string]Item) *cache {
if de == 0 {
de = -1
}
c := &cache{
defaultExpiration: de,
items: m,
}
return c
}
func newCacheWithJanitor(de time.Duration, ci time.Duration, m map[string]Item, onEvicted func(k string, v ValueType_tpl)) *Cache_tpl {
c := newCache(de, m)
c.onEvicted = onEvicted
// This trick ensures that the janitor goroutine (which--granted it
// was enabled--is running DeleteExpired on c forever) does not keep
// the returned C object from being garbage collected. When it is
// garbage collected, the finalizer stops the janitor goroutine, after
// which c can be collected.
C := &Cache_tpl{c}
if ci > 0 {
runJanitor(c, ci)
runtime.SetFinalizer(C, stopJanitor)
}
return C
}
// New Returns a new cache with a given default expiration duration and
@ -325,6 +290,24 @@ func newCacheWithJanitor(de time.Duration, ci time.Duration, m map[string]Item,
// expired items are not deleted from the cache before calling c.DeleteExpired().
//
func New_tpl(attr Attr_tpl) *Cache_tpl {
items := make(map[string]Item, attr.Size)
return newCacheWithJanitor(attr.DefaultExpiration, attr.DefaultCleanupInterval, items, attr.OnEvicted)
items := make(map[string]Item_tpl, attr.Size)
if attr.DefaultExpiration == 0 {
attr.DefaultExpiration = -1
}
c := &cache_tpl{
defaultExpiration: attr.DefaultExpiration,
items: items,
}
c.onEvicted = attr.OnEvicted
// This trick ensures that the janitor goroutine (which--granted it
// was enabled--is running DeleteExpired on c forever) does not keep
// the returned C object from being garbage collected. When it is
// garbage collected, the finalizer stops the janitor goroutine, after
// which c can be collected.
C := &Cache_tpl{c}
if attr.DefaultCleanupInterval > 0 {
c.runJanitor(attr.DefaultCleanupInterval)
runtime.SetFinalizer(C, c.stopJanitor)
}
return C
}

152
cachemap/cache.tmpl
View File

@ -22,34 +22,34 @@ type {{.ValueType}}CacheAttr struct {
}
// Item struct
type Item struct {
type {{.ValueType}}Item struct {
Object {{.ValueType}}
Expiration int64
}
// Expired returns true if the item has expired.
func (item Item) Expired() bool {
func (item {{.ValueType}}Item) Expired() bool {
return item.Expiration != 0 && time.Now().UnixNano() > item.Expiration
}
// Cache struct
type {{.ValueType}}Cache struct {
*cache
*{{.ValueType}}cache
// If this is confusing, see the comment at the bottom of New()
}
type cache struct {
type {{.ValueType}}cache struct {
defaultExpiration time.Duration
items map[string]Item
items map[string]{{.ValueType}}Item
mu sync.RWMutex
onEvicted func(string, {{.ValueType}})
janitor *janitor
stop chan bool
}
// Add an item to the cache, replacing any existing item. If the duration is 0
// (DefaultExpiration), the cache's default expiration time is used. If it is -1
// (NoExpiration), the item never expires.
func (c *cache) Set(k string, x {{.ValueType}}, d time.Duration) {
func (c *{{.ValueType}}cache) Set(k string, x {{.ValueType}}, d time.Duration) {
// "Inlining" of set
var e int64
if d == DefaultExpiration {
@ -59,7 +59,7 @@ func (c *cache) Set(k string, x {{.ValueType}}, d time.Duration) {
e = time.Now().Add(d).UnixNano()
}
c.mu.Lock()
c.items[k] = Item{
c.items[k] = {{.ValueType}}Item{
Object: x,
Expiration: e,
}
@ -68,7 +68,7 @@ func (c *cache) Set(k string, x {{.ValueType}}, d time.Duration) {
c.mu.Unlock()
}
func (c *cache) set(k string, x {{.ValueType}}, d time.Duration) {
func (c *{{.ValueType}}cache) set(k string, x {{.ValueType}}, d time.Duration) {
var e int64
if d == DefaultExpiration {
d = c.defaultExpiration
@ -76,7 +76,7 @@ func (c *cache) set(k string, x {{.ValueType}}, d time.Duration) {
if d > 0 {
e = time.Now().Add(d).UnixNano()
}
c.items[k] = Item{
c.items[k] = {{.ValueType}}Item{
Object: x,
Expiration: e,
}
@ -84,7 +84,7 @@ func (c *cache) set(k string, x {{.ValueType}}, d time.Duration) {
// Add 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 otherwise.
func (c *cache) Add(k string, x {{.ValueType}}, d time.Duration) error {
func (c *{{.ValueType}}cache) Add(k string, x {{.ValueType}}, d time.Duration) error {
c.mu.Lock()
_, found := c.get(k)
if found {
@ -98,7 +98,7 @@ func (c *cache) Add(k string, x {{.ValueType}}, d time.Duration) error {
// Set a new value for the cache key only if it already exists, and the existing
// item hasn't expired. Returns an error otherwise.
func (c *cache) Replace(k string, x {{.ValueType}}, d time.Duration) error {
func (c *{{.ValueType}}cache) Replace(k string, x {{.ValueType}}, d time.Duration) error {
c.mu.Lock()
_, found := c.get(k)
if !found {
@ -112,7 +112,7 @@ func (c *cache) Replace(k string, x {{.ValueType}}, d time.Duration) error {
// Get an item from the cache. Returns the item or nil, and a bool indicating
// whether the key was found.
func (c *cache) Get(k string) ({{.ValueType}}, bool) {
func (c *{{.ValueType}}cache) Get(k string) ({{.ValueType}}, bool) {
c.mu.RLock()
// "Inlining" of get and Expired
item, found := c.items[k]
@ -125,7 +125,7 @@ func (c *cache) Get(k string) ({{.ValueType}}, bool) {
return item.Object, true
}
func (c *cache) get(k string) (*{{.ValueType}}, bool) {
func (c *{{.ValueType}}cache) get(k string) (*{{.ValueType}}, bool) {
item, found := c.items[k]
if !found || item.Expiration > 0 && time.Now().UnixNano() > item.Expiration {
return nil, false
@ -140,7 +140,7 @@ func (c *cache) get(k string) (*{{.ValueType}}, bool) {
// item's value is not an integer, if it was not found, or if it is not
// possible to increment it by n. To retrieve the incremented value, use one
// of the specialized methods, e.g. IncrementInt64.
func (c *cache) Increment(k string, n {{.ValueType}}) error {
func (c *{{.ValueType}}cache) Increment(k string, n {{.ValueType}}) error {
c.mu.Lock()
v, found := c.items[k]
if !found || v.Expired() {
@ -158,7 +158,7 @@ func (c *cache) Increment(k string, n {{.ValueType}}) error {
// item's value is not an integer, if it was not found, or if it is not
// possible to decrement it by n. To retrieve the decremented value, use one
// of the specialized methods, e.g. DecrementInt64.
func (c *cache) Decrement(k string, n {{.ValueType}}) error {
func (c *{{.ValueType}}cache) Decrement(k string, n {{.ValueType}}) error {
// TODO: Implement Increment and Decrement more cleanly.
// (Cannot do Increment(k, n*-1) for uints.)
c.mu.Lock()
@ -167,6 +167,7 @@ func (c *cache) Decrement(k string, n {{.ValueType}}) error {
c.mu.Unlock()
return fmt.Errorf("Item not found")
}
v.Object -= n
c.items[k] = v
c.mu.Unlock()
return nil
@ -175,7 +176,7 @@ func (c *cache) Decrement(k string, n {{.ValueType}}) error {
{{end}}
// Delete an item from the cache. Does nothing if the key is not in the cache.
func (c *cache) Delete(k string) {
func (c *{{.ValueType}}cache) Delete(k string) {
// fast path
if c.onEvicted == nil {
c.mu.Lock()
@ -192,7 +193,7 @@ func (c *cache) Delete(k string) {
}
}
func (c *cache) delete(k string) ({{.ValueType}}, bool) {
func (c *{{.ValueType}}cache) delete(k string) ({{.ValueType}}, bool) {
if v, found := c.items[k]; found {
delete(c.items, k)
return v.Object, true
@ -200,18 +201,16 @@ func (c *cache) delete(k string) ({{.ValueType}}, bool) {
return {{.ZeroValue}}, false
}
func (c *cache) deleteFast(k string) {
func (c *{{.ValueType}}cache) deleteFast(k string) {
delete(c.items, k)
}
type keyAndValue struct {
key string
value {{.ValueType}}
}
// Delete all expired items from the cache.
func (c *cache) DeleteExpired() {
var evictedItems []keyAndValue
func (c *{{.ValueType}}cache) DeleteExpired() {
var evictedItems []struct{
key string
value {{.ValueType}}
}
now := time.Now().UnixNano()
// fast path
if c.onEvicted == nil {
@ -232,7 +231,10 @@ func (c *cache) DeleteExpired() {
if v.Expiration > 0 && now > v.Expiration {
ov, evicted := c.delete(k)
if evicted {
evictedItems = append(evictedItems, keyAndValue{k, ov})
evictedItems = append(evictedItems, struct{
key string
value {{.ValueType}}
}{k, ov})
}
}
}
@ -244,7 +246,7 @@ func (c *cache) DeleteExpired() {
// Returns the number of items in the cache. This may include items that have
// expired, but have not yet been cleaned up. Equivalent to len(c.Items()).
func (c *cache) ItemCount() int {
func (c *{{.ValueType}}cache) ItemCount() int {
c.mu.RLock()
n := len(c.items)
c.mu.RUnlock()
@ -252,68 +254,32 @@ func (c *cache) ItemCount() int {
}
// Delete all items from the cache.
func (c *cache) Flush() {
func (c *{{.ValueType}}cache) Flush() {
c.mu.Lock()
c.items = map[string]Item{}
c.items = map[string]{{.ValueType}}Item{}
c.mu.Unlock()
}
type janitor struct {
Interval time.Duration
stop chan bool
// _ *{{.ValueType}}cache is used as a namespace, so that "stopJanitor" will not conflicts for the name.
func (_ *{{.ValueType}}cache) stopJanitor(c *{{.ValueType}}Cache) {
c.stop <- true
}
func (j *janitor) Run(c *cache) {
j.stop = make(chan bool)
ticker := time.NewTicker(j.Interval)
for {
select {
case <-ticker.C:
c.DeleteExpired()
case <-j.stop:
ticker.Stop()
return
func (c *{{.ValueType}}cache) runJanitor(ci time.Duration) {
c.stop = make(chan bool)
go func() {
ticker := time.NewTicker(ci)
for {
select {
case <-ticker.C:
c.DeleteExpired()
case <-c.stop:
ticker.Stop()
return
}
}
}
}
}()
func stopJanitor(c *{{.ValueType}}Cache) {
c.janitor.stop <- true
}
func runJanitor(c *cache, ci time.Duration) {
j := &janitor{
Interval: ci,
}
c.janitor = j
go j.Run(c)
}
func newCache(de time.Duration, m map[string]Item) *cache {
if de == 0 {
de = -1
}
c := &cache{
defaultExpiration: de,
items: m,
}
return c
}
func newCacheWithJanitor(de time.Duration, ci time.Duration, m map[string]Item, onEvicted func(k string, v {{.ValueType}})) *{{.ValueType}}Cache {
c := newCache(de, m)
c.onEvicted = onEvicted
// This trick ensures that the janitor goroutine (which--granted it
// was enabled--is running DeleteExpired on c forever) does not keep
// the returned C object from being garbage collected. When it is
// garbage collected, the finalizer stops the janitor goroutine, after
// which c can be collected.
C := &{{.ValueType}}Cache{c}
if ci > 0 {
runJanitor(c, ci)
runtime.SetFinalizer(C, stopJanitor)
}
return C
}
// New Returns a new cache with a given default expiration duration and
@ -323,6 +289,24 @@ func newCacheWithJanitor(de time.Duration, ci time.Duration, m map[string]Item,
// expired items are not deleted from the cache before calling c.DeleteExpired().
//
func New{{.ValueType}}Cache(attr {{.ValueType}}CacheAttr) *{{.ValueType}}Cache {
items := make(map[string]Item, attr.Size)
return newCacheWithJanitor(attr.DefaultExpiration, attr.DefaultCleanupInterval, items, attr.OnEvicted)
items := make(map[string]{{.ValueType}}Item, attr.Size)
if attr.DefaultExpiration == 0 {
attr.DefaultExpiration = -1
}
c := &{{.ValueType}}cache{
defaultExpiration: attr.DefaultExpiration,
items: items,
}
c.onEvicted = attr.OnEvicted
// This trick ensures that the janitor goroutine (which--granted it
// was enabled--is running DeleteExpired on c forever) does not keep
// the returned C object from being garbage collected. When it is
// garbage collected, the finalizer stops the janitor goroutine, after
// which c can be collected.
C := &{{.ValueType}}Cache{c}
if attr.DefaultCleanupInterval > 0 {
c.runJanitor(attr.DefaultCleanupInterval)
runtime.SetFinalizer(C, c.stopJanitor)
}
return C
}

2
cachemap/const.tmpl
View File

@ -15,5 +15,3 @@ const (
// created (e.g. 5 minutes.)
DefaultExpiration time.Duration = 0
)

12
sharded.go
View File

@ -26,7 +26,7 @@ type unexportedShardedCache struct {
type shardedCache struct {
seed uint32
m uint32
cs []*cache
cs []*cache_tpl
janitor *shardedJanitor
}
@ -62,7 +62,7 @@ func djb33(seed uint32, k string) uint32 {
return d ^ (d >> 16)
}
func (sc *shardedCache) bucket(k string) *cache {
func (sc *shardedCache) bucket(k string) *cache_tpl {
return sc.cs[djb33(sc.seed, k)%sc.m]
}
@ -106,7 +106,7 @@ func (sc *shardedCache) DeleteExpired() {
// is needed to use a cache and its corresponding Items() return values at
// the same time, as the maps are shared.
// TODO: 不准备暴露这个接口,使用者不应该知道底层的数据.
func (sc *shardedCache) items() []map[string]Item {
func (sc *shardedCache) items() []map[string]Item_tpl {
return nil
}
@ -159,12 +159,12 @@ func newShardedCache(n int, de time.Duration) *shardedCache {
sc := &shardedCache{
seed: seed,
m: uint32(n),
cs: make([]*cache, n),
cs: make([]*cache_tpl, n),
}
for i := 0; i < n; i++ {
c := &cache{
c := &cache_tpl{
defaultExpiration: de,
items: map[string]Item{},
items: map[string]Item_tpl{},
}
sc.cs[i] = c
}