forked from bluele/gcache
/
cache.go
148 lines (124 loc) · 3.02 KB
/
cache.go
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package gcache
import (
"errors"
"sync"
"time"
)
const (
TYPE_SIMPLE = "simple"
TYPE_LRU = "lru"
TYPE_LFU = "lfu"
TYPE_ARC = "arc"
)
var KeyNotFoundError = errors.New("Key not found.")
type Cache interface {
Set(interface{}, interface{})
Get(interface{}) (interface{}, error)
GetIFPresent(interface{}) (interface{}, error)
GetALL() map[interface{}]interface{}
get(interface{}, bool) (interface{}, error)
Remove(interface{}) bool
Purge()
Keys() []interface{}
Len() int
statsAccessor
}
type baseCache struct {
size int
loaderFunc *LoaderFunc
evictedFunc *EvictedFunc
addedFunc *AddedFunc
expiration *time.Duration
mu sync.RWMutex
loadGroup Group
*stats
}
type LoaderFunc func(interface{}) (interface{}, error)
type EvictedFunc func(interface{}, interface{})
type AddedFunc func(interface{}, interface{})
type CacheBuilder struct {
tp string
size int
loaderFunc *LoaderFunc
evictedFunc *EvictedFunc
addedFunc *AddedFunc
expiration *time.Duration
}
func New(size int) *CacheBuilder {
if size <= 0 {
panic("gcache: size <= 0")
}
return &CacheBuilder{
tp: TYPE_SIMPLE,
size: size,
}
}
// Set a loader function.
// loaderFunc: create a new value with this function if cached value is expired.
func (cb *CacheBuilder) LoaderFunc(loaderFunc LoaderFunc) *CacheBuilder {
cb.loaderFunc = &loaderFunc
return cb
}
func (cb *CacheBuilder) EvictType(tp string) *CacheBuilder {
cb.tp = tp
return cb
}
func (cb *CacheBuilder) Simple() *CacheBuilder {
return cb.EvictType(TYPE_SIMPLE)
}
func (cb *CacheBuilder) LRU() *CacheBuilder {
return cb.EvictType(TYPE_LRU)
}
func (cb *CacheBuilder) LFU() *CacheBuilder {
return cb.EvictType(TYPE_LFU)
}
func (cb *CacheBuilder) ARC() *CacheBuilder {
return cb.EvictType(TYPE_ARC)
}
func (cb *CacheBuilder) EvictedFunc(evictedFunc EvictedFunc) *CacheBuilder {
cb.evictedFunc = &evictedFunc
return cb
}
func (cb *CacheBuilder) AddedFunc(addedFunc AddedFunc) *CacheBuilder {
cb.addedFunc = &addedFunc
return cb
}
func (cb *CacheBuilder) Expiration(expiration time.Duration) *CacheBuilder {
cb.expiration = &expiration
return cb
}
func (cb *CacheBuilder) Build() Cache {
return cb.build()
}
func (cb *CacheBuilder) build() Cache {
switch cb.tp {
case TYPE_SIMPLE:
return newSimpleCache(cb)
case TYPE_LRU:
return newLRUCache(cb)
case TYPE_LFU:
return newLFUCache(cb)
case TYPE_ARC:
return newARC(cb)
default:
panic("gcache: Unknown type " + cb.tp)
}
}
func buildCache(c *baseCache, cb *CacheBuilder) {
c.size = cb.size
c.loaderFunc = cb.loaderFunc
c.expiration = cb.expiration
c.addedFunc = cb.addedFunc
c.evictedFunc = cb.evictedFunc
c.stats = &stats{}
}
// load a new value using by specified key.
func (c *baseCache) load(key interface{}, cb func(interface{}, error) (interface{}, error), isWait bool) (interface{}, bool, error) {
v, called, err := c.loadGroup.Do(key, func() (interface{}, error) {
return cb((*c.loaderFunc)(key))
}, isWait)
if err != nil {
return nil, called, err
}
return v, called, nil
}