146 lines
2.8 KiB
Go
146 lines
2.8 KiB
Go
package cache
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import (
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"encoding/json"
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"errors"
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"fmt"
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"strconv"
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"sync"
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"time"
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)
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var (
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DefaultEvery int = 60 // 1 minute
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)
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type MemoryItem struct {
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val interface{}
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Lastaccess time.Time
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expired int
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}
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func (itm *MemoryItem) Access() interface{} {
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itm.Lastaccess = time.Now()
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return itm.val
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}
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type MemoryCache struct {
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lock sync.RWMutex
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dur time.Duration
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items map[string]*MemoryItem
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Every int // Run an expiration check Every seconds
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}
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// NewDefaultCache returns a new FileCache with sane defaults.
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func NewMemoryCache() *MemoryCache {
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cache := MemoryCache{items: make(map[string]*MemoryItem)}
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return &cache
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}
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func (bc *MemoryCache) Get(name string) interface{} {
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bc.lock.RLock()
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defer bc.lock.RUnlock()
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itm, ok := bc.items[name]
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if !ok {
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return nil
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}
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return itm.Access()
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}
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func (bc *MemoryCache) Put(name string, value interface{}, expired int) error {
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bc.lock.Lock()
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defer bc.lock.Unlock()
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t := MemoryItem{val: value, Lastaccess: time.Now(), expired: expired}
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if _, ok := bc.items[name]; ok {
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return errors.New("the key is exist")
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} else {
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bc.items[name] = &t
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}
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return nil
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}
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func (bc *MemoryCache) Delete(name string) error {
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bc.lock.Lock()
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defer bc.lock.Unlock()
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if _, ok := bc.items[name]; !ok {
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return errors.New("key not exist")
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}
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delete(bc.items, name)
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_, valid := bc.items[name]
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if valid {
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return errors.New("delete key error")
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}
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return nil
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}
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func (bc *MemoryCache) IsExist(name string) bool {
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bc.lock.RLock()
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defer bc.lock.RUnlock()
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_, ok := bc.items[name]
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return ok
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}
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func (bc *MemoryCache) ClearAll() error {
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bc.lock.Lock()
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defer bc.lock.Unlock()
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bc.items = make(map[string]*MemoryItem)
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return nil
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}
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// Start activates the file cache; it will
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func (bc *MemoryCache) StartAndGC(config string) error {
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var cf map[string]int
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json.Unmarshal([]byte(config), &cf)
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if _, ok := cf["every"]; !ok {
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cf = make(map[string]int)
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cf["interval"] = DefaultEvery
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}
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dur, err := time.ParseDuration(fmt.Sprintf("%ds", cf["interval"]))
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if err != nil {
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return err
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}
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bc.Every = cf["interval"]
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bc.dur = dur
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go bc.vaccuum()
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return nil
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}
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func (bc *MemoryCache) vaccuum() {
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if bc.Every < 1 {
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return
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}
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for {
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<-time.After(time.Duration(bc.dur) * time.Second)
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if bc.items == nil {
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return
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}
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for name, _ := range bc.items {
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bc.item_expired(name)
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}
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}
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}
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// item_expired returns true if an item is expired.
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func (bc *MemoryCache) item_expired(name string) bool {
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bc.lock.Lock()
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defer bc.lock.Unlock()
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itm, ok := bc.items[name]
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if !ok {
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return true
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}
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dur := time.Now().Sub(itm.Lastaccess)
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sec, err := strconv.Atoi(fmt.Sprintf("%0.0f", dur.Seconds()))
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if err != nil {
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delete(bc.items, name)
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return true
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} else if sec >= itm.expired {
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delete(bc.items, name)
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return true
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}
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return false
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}
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func init() {
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Register("memory", NewMemoryCache())
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}
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