first

lib/cache/file.go

@@ -0,0 +1,103 @@
+package cache
+
+import (
+	"crypto/md5"
+	"fmt"
+	"os"
+	"sync"
+	"time"
+)
+
+type FileCache struct {
+	mu    sync.Mutex
+	locks map[string]*sync.Mutex
+	Dir   string
+}
+
+func (fc *FileCache) getLock(key string) *sync.Mutex {
+	fc.mu.Lock()
+	defer fc.mu.Unlock()
+	if fc.locks == nil {
+		fc.locks = make(map[string]*sync.Mutex)
+	}
+	if _, ok := fc.locks[key]; !ok {
+		fc.locks[key] = new(sync.Mutex)
+	}
+	return fc.locks[key]
+}
+
+func (c *FileCache) Get(key string, value interface{}) error {
+	data, _ := c.getValue(key)
+	err := DecodeValue(data, value)
+	return err
+}
+
+// 获取值,如果文件不存在或者过期，返回空，过滤掉错误
+func (c *FileCache) getValue(key string) (string, error) {
+	f := c.fileName(key)
+	fileInfo, err := os.Stat(f)
+	if err != nil {
+		//文件不存在
+		return "", nil
+	}
+	difT := time.Now().Sub(fileInfo.ModTime())
+	if difT >= 0 {
+		os.Remove(f)
+		return "", nil
+	}
+	data, err := os.ReadFile(f)
+	if err != nil {
+		return "", nil
+	}
+	return string(data), nil
+}
+
+// 保存值
+func (c *FileCache) saveValue(key string, value string, exp int) error {
+	f := c.fileName(key)
+	lock := c.getLock(f)
+	lock.Lock()
+	defer lock.Unlock()
+
+	err := os.WriteFile(f, ([]byte)(value), 0644)
+	if err != nil {
+		return err
+	}
+	if exp <= 0 {
+		exp = MaxTimeOut
+	}
+	expFromNow := time.Now().Add(time.Duration(exp) * time.Second)
+	err = os.Chtimes(f, expFromNow, expFromNow)
+	return err
+}
+
+func (c *FileCache) Set(key string, value interface{}, exp int) error {
+	str, err := EncodeValue(value)
+	if err != nil {
+		return err
+	}
+
+	err = c.saveValue(key, str, exp)
+	return err
+}
+
+func (c *FileCache) SetDir(path string) {
+	c.Dir = path
+}
+
+func (c *FileCache) fileName(key string) string {
+	f := c.Dir + string(os.PathSeparator) + fmt.Sprintf("%x", md5.Sum([]byte(key)))
+	return f
+}
+
+func (c *FileCache) Gc() error {
+	//检查文件过期时间，并删除
+	return nil
+}
+
+func NewFileCache() *FileCache {
+	return &FileCache{
+		locks: make(map[string]*sync.Mutex),
+		Dir:   os.TempDir(),
+	}
+}