Feature: support store group selected node to cache (enable by default)

component/profile/cachefile/cache.go

@@ -0,0 +1,115 @@
+package cachefile
+
+import (
+	"bytes"
+	"encoding/gob"
+	"io/ioutil"
+	"os"
+	"sync"
+
+	"github.com/Dreamacro/clash/component/profile"
+	C "github.com/Dreamacro/clash/constant"
+	"github.com/Dreamacro/clash/log"
+)
+
+var (
+	initOnce     sync.Once
+	fileMode     os.FileMode = 0666
+	defaultCache *CacheFile
+)
+
+type cache struct {
+	Selected map[string]string
+}
+
+// CacheFile store and update the cache file
+type CacheFile struct {
+	path  string
+	model *cache
+	enc   *gob.Encoder
+	buf   *bytes.Buffer
+	mux   sync.Mutex
+}
+
+func (c *CacheFile) SetSelected(group, selected string) {
+	if !profile.StoreSelected.Load() {
+		return
+	}
+
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	model, err := c.element()
+	if err != nil {
+		log.Warnln("[CacheFile] read cache %s failed: %s", c.path, err.Error())
+		return
+	}
+
+	model.Selected[group] = selected
+	c.buf.Reset()
+	if err := c.enc.Encode(model); err != nil {
+		log.Warnln("[CacheFile] encode gob failed: %s", err.Error())
+		return
+	}
+
+	if err := ioutil.WriteFile(c.path, c.buf.Bytes(), fileMode); err != nil {
+		log.Warnln("[CacheFile] write cache to %s failed: %s", c.path, err.Error())
+		return
+	}
+}
+
+func (c *CacheFile) SelectedMap() map[string]string {
+	if !profile.StoreSelected.Load() {
+		return nil
+	}
+
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	model, err := c.element()
+	if err != nil {
+		log.Warnln("[CacheFile] read cache %s failed: %s", c.path, err.Error())
+		return nil
+	}
+
+	mapping := map[string]string{}
+	for k, v := range model.Selected {
+		mapping[k] = v
+	}
+	return mapping
+}
+
+func (c *CacheFile) element() (*cache, error) {
+	if c.model != nil {
+		return c.model, nil
+	}
+
+	model := &cache{
+		Selected: map[string]string{},
+	}
+
+	if buf, err := ioutil.ReadFile(c.path); err == nil {
+		bufReader := bytes.NewBuffer(buf)
+		dec := gob.NewDecoder(bufReader)
+		if err := dec.Decode(model); err != nil {
+			return nil, err
+		}
+	}
+
+	c.model = model
+	return c.model, nil
+}
+
+// Cache return singleton of CacheFile
+func Cache() *CacheFile {
+	initOnce.Do(func() {
+		buf := &bytes.Buffer{}
+		defaultCache = &CacheFile{
+			path: C.Path.Cache(),
+			buf:  buf,
+			enc:  gob.NewEncoder(buf),
+		}
+	})
+
+	return defaultCache
+}