180 lines
3.7 KiB
Go
180 lines
3.7 KiB
Go
// Copyright 2013 Beego Authors
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// Copyright 2014 The Macaron Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License"): you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations
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// under the License.
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package cache
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import (
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"errors"
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"sync"
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"time"
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)
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// MemoryItem represents a memory cache item.
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type MemoryItem struct {
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val interface{}
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created int64
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expire int64
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}
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func (item *MemoryItem) hasExpired() bool {
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return item.expire > 0 &&
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(time.Now().Unix()-item.created) >= item.expire
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}
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// MemoryCacher represents a memory cache adapter implementation.
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type MemoryCacher struct {
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lock sync.RWMutex
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items map[string]*MemoryItem
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interval int // GC interval.
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}
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// NewMemoryCacher creates and returns a new memory cacher.
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func NewMemoryCacher() *MemoryCacher {
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return &MemoryCacher{items: make(map[string]*MemoryItem)}
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}
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// Put puts value into cache with key and expire time.
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// If expired is 0, it will be deleted by next GC operation.
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func (c *MemoryCacher) Put(key string, val interface{}, expire int64) error {
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c.lock.Lock()
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defer c.lock.Unlock()
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c.items[key] = &MemoryItem{
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val: val,
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created: time.Now().Unix(),
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expire: expire,
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}
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return nil
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}
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// Get gets cached value by given key.
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func (c *MemoryCacher) Get(key string) interface{} {
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c.lock.RLock()
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defer c.lock.RUnlock()
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item, ok := c.items[key]
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if !ok {
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return nil
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}
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if item.hasExpired() {
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go c.Delete(key)
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return nil
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}
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return item.val
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}
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// Delete deletes cached value by given key.
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func (c *MemoryCacher) Delete(key string) error {
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c.lock.Lock()
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defer c.lock.Unlock()
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delete(c.items, key)
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return nil
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}
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// Incr increases cached int-type value by given key as a counter.
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func (c *MemoryCacher) Incr(key string) (err error) {
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c.lock.RLock()
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defer c.lock.RUnlock()
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item, ok := c.items[key]
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if !ok {
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return errors.New("key not exist")
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}
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item.val, err = Incr(item.val)
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return err
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}
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// Decr decreases cached int-type value by given key as a counter.
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func (c *MemoryCacher) Decr(key string) (err error) {
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c.lock.RLock()
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defer c.lock.RUnlock()
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item, ok := c.items[key]
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if !ok {
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return errors.New("key not exist")
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}
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item.val, err = Decr(item.val)
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return err
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}
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// IsExist returns true if cached value exists.
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func (c *MemoryCacher) IsExist(key string) bool {
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c.lock.RLock()
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defer c.lock.RUnlock()
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_, ok := c.items[key]
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return ok
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}
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// Flush deletes all cached data.
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func (c *MemoryCacher) Flush() error {
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c.lock.Lock()
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defer c.lock.Unlock()
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c.items = make(map[string]*MemoryItem)
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return nil
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}
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func (c *MemoryCacher) checkRawExpiration(key string) {
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item, ok := c.items[key]
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if !ok {
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return
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}
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if item.hasExpired() {
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delete(c.items, key)
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}
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}
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func (c *MemoryCacher) checkExpiration(key string) {
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c.lock.Lock()
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defer c.lock.Unlock()
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c.checkRawExpiration(key)
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}
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func (c *MemoryCacher) startGC() {
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c.lock.Lock()
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defer c.lock.Unlock()
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if c.interval < 1 {
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return
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}
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if c.items != nil {
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for key, _ := range c.items {
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c.checkRawExpiration(key)
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}
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}
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time.AfterFunc(time.Duration(c.interval)*time.Second, func() { c.startGC() })
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}
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// StartAndGC starts GC routine based on config string settings.
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func (c *MemoryCacher) StartAndGC(opt Options) error {
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c.lock.Lock()
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c.interval = opt.Interval
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c.lock.Unlock()
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go c.startGC()
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return nil
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}
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func init() {
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Register("memory", NewMemoryCacher())
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}
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