Update leveldb

Signed-off-by: Yuan Si <do4suki@gmail.com>

db/db.go

@@ -0,0 +1,21 @@
+package db
+
+import "fmt"
+
+var (
+	DB *Instance
+)
+
+func init() {
+	DB = GetInstance()
+}
+
+func MatchTokenUid(token, uid string) bool {
+	res, err := DB.Get([]byte(uid))
+	if err != nil {
+		fmt.Println(err)
+		return false
+	}
+
+	return string(res) == token
+}

db/leveldb.go

@@ -0,0 +1,58 @@
+package db
+
+import (
+	"errors"
+	"sync"
+
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+var (
+	once sync.Once
+)
+
+type Instance struct {
+	db *leveldb.DB
+	mu sync.Mutex
+}
+
+func GetInstance() *Instance {
+	in := Instance{}
+	once.Do(func() {
+		var err error
+		in.db, err = leveldb.OpenFile("./data/honoka-chan.db", nil)
+		if err != nil {
+			panic(err)
+		}
+	})
+	return &in
+}
+
+func (in *Instance) Close() error {
+	in.mu.Lock()
+	defer in.mu.Unlock()
+	if in.db != nil {
+		return in.db.Close()
+	}
+	return nil
+}
+
+func (in *Instance) Get(key []byte) ([]byte, error) {
+	if len(key) == 0 {
+		return nil, errors.New("empty key")
+	}
+	res, err := in.db.Get(key, nil)
+	if err == leveldb.ErrNotFound {
+		return nil, nil
+	} else if err != nil {
+		return nil, err
+	}
+	return res, nil
+}
+
+func (in *Instance) Set(key, value []byte) error {
+	if len(key) == 0 {
+		return errors.New("empty key")
+	}
+	return in.db.Put(key, value, nil)
+}