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// Copyright 2013 Beego Authors
// Copyright 2014 The Macaron Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.
package cache
import (
"crypto/md5"
"encoding/hex"
"fmt"
"io/ioutil"
"log"
"os"
"path/filepath"
"sync"
"time"
"github.com/unknwon/com"
)
// Item represents a cache item.
type Item struct {
Val interface{}
Created int64
Expire int64
}
func (item *Item) hasExpired() bool {
return item.Expire > 0 &&
(time.Now().Unix()-item.Created) >= item.Expire
}
// FileCacher represents a file cache adapter implementation.
type FileCacher struct {
lock sync.Mutex
rootPath string
interval int // GC interval.
}
// NewFileCacher creates and returns a new file cacher.
func NewFileCacher() *FileCacher {
return &FileCacher{}
}
func (c *FileCacher) filepath(key string) string {
m := md5.Sum([]byte(key))
hash := hex.EncodeToString(m[:])
return filepath.Join(c.rootPath, string(hash[0]), string(hash[1]), hash)
}
// Put puts value into cache with key and expire time.
// If expired is 0, it will be deleted by next GC operation.
func (c *FileCacher) Put(key string, val interface{}, expire int64) error {
filename := c.filepath(key)
item := &Item{val, time.Now().Unix(), expire}
data, err := EncodeGob(item)
if err != nil {
return err
}
os.MkdirAll(filepath.Dir(filename), os.ModePerm)
return ioutil.WriteFile(filename, data, os.ModePerm)
}
func (c *FileCacher) read(key string) (*Item, error) {
filename := c.filepath(key)
data, err := ioutil.ReadFile(filename)
if err != nil {
return nil, err
}
item := new(Item)
return item, DecodeGob(data, item)
}
// Get gets cached value by given key.
func (c *FileCacher) Get(key string) interface{} {
item, err := c.read(key)
if err != nil {
return nil
}
if item.hasExpired() {
os.Remove(c.filepath(key))
return nil
}
return item.Val
}
// Delete deletes cached value by given key.
func (c *FileCacher) Delete(key string) error {
return os.Remove(c.filepath(key))
}
// Incr increases cached int-type value by given key as a counter.
func (c *FileCacher) Incr(key string) error {
item, err := c.read(key)
if err != nil {
return err
}
item.Val, err = Incr(item.Val)
if err != nil {
return err
}
return c.Put(key, item.Val, item.Expire)
}
// Decrease cached int value.
func (c *FileCacher) Decr(key string) error {
item, err := c.read(key)
if err != nil {
return err
}
item.Val, err = Decr(item.Val)
if err != nil {
return err
}
return c.Put(key, item.Val, item.Expire)
}
// IsExist returns true if cached value exists.
func (c *FileCacher) IsExist(key string) bool {
return com.IsExist(c.filepath(key))
}
// Flush deletes all cached data.
func (c *FileCacher) Flush() error {
return os.RemoveAll(c.rootPath)
}
func (c *FileCacher) startGC() {
c.lock.Lock()
defer c.lock.Unlock()
if c.interval < 1 {
return
}
if err := filepath.Walk(c.rootPath, func(path string, fi os.FileInfo, err error) error {
if err != nil {
return fmt.Errorf("Walk: %v", err)
}
if fi.IsDir() {
return nil
}
data, err := ioutil.ReadFile(path)
if err != nil && !os.IsNotExist(err) {
fmt.Errorf("ReadFile: %v", err)
}
item := new(Item)
if err = DecodeGob(data, item); err != nil {
return err
}
if item.hasExpired() {
if err = os.Remove(path); err != nil && !os.IsNotExist(err) {
return fmt.Errorf("Remove: %v", err)
}
}
return nil
}); err != nil {
log.Printf("error garbage collecting cache files: %v", err)
}
time.AfterFunc(time.Duration(c.interval)*time.Second, func() { c.startGC() })
}
// StartAndGC starts GC routine based on config string settings.
func (c *FileCacher) StartAndGC(opt Options) error {
c.lock.Lock()
c.rootPath = opt.AdapterConfig
c.interval = opt.Interval
if !filepath.IsAbs(c.rootPath) {
panic("rootPath must be an absolute path")
}
c.lock.Unlock()
if err := os.MkdirAll(c.rootPath, os.ModePerm); err != nil {
return err
}
go c.startGC()
return nil
}
func init() {
Register("file", NewFileCacher())
}
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