implement file tree

db.go

@@ -32,6 +32,8 @@ func New(key Type, params ...string) (db DB, err error) {
 		err = nil
 	case RCLONE:
 		db, err = NewRClone(params[0], params[1])
+	case FILES:
+		db, err = NewFiles(params[0])
 	case BOLT:
 		db, err = NewBolt(params[0])
 	case MINIO:

db_test.go

@@ -96,6 +96,12 @@ func TestImplementations(t *testing.T) {
 		cases = append(cases, bolt)
 	}
 
+	if files, err := NewFiles(path.Join(dir, "files")); err != nil {
+		t.Errorf("cannot make files: %v", err)
+	} else {
+		cases = append(cases, files)
+	}
+
 	if leveldb, err := NewLevelDB(path.Join(dir, "leveldb")); err != nil {
 		t.Errorf("cannot make leveldb: %v", err)
 	} else {

files.go

@@ -0,0 +1,70 @@
+package storage
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+type Files struct {
+	root string
+}
+
+func NewFiles(root string) (*Files, error) {
+	_, err := os.Stat(path.Dir(root))
+	if err != nil {
+		return nil, err
+	}
+	root, err = filepath.Abs(root)
+	if err != nil {
+		return nil, err
+	}
+	return &Files{
+		root: root,
+	}, os.MkdirAll(root, os.ModePerm)
+}
+
+func (b *Files) List(ns []string, limits ...string) ([]string, error) {
+	namespace := resolveNamespace(ns)
+	files := make([]string, 0)
+	err := filepath.Walk(b.root, func(p string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+		if !strings.HasPrefix(strings.TrimPrefix(p, b.root+"/"), namespace) {
+			return nil
+		}
+		files = append(files, path.Join(b.root, p))
+		return nil
+	})
+	return files, err
+	/*
+		namespace := resolveNamespace(ns)
+		limits = resolveLimits(limits)
+	*/
+}
+
+func (b *Files) Get(key string, ns ...string) ([]byte, error) {
+	namespace := resolveNamespace(ns)
+	path := path.Join(b.root, namespace, key)
+	return ioutil.ReadFile(path)
+}
+
+func (b *Files) Set(key string, value []byte, ns ...string) error {
+	namespace := resolveNamespace(ns)
+	dir := path.Join(b.root, namespace)
+	if err := os.MkdirAll(dir, os.ModePerm); err != nil {
+		return err
+	}
+	path := path.Join(dir, key)
+	return ioutil.WriteFile(path, value, os.ModePerm)
+}
+
+func (b *Files) Close() error {
+	return nil
+}

type.go

@@ -11,6 +11,7 @@ const (
 	REDIS           = Type(iota)
 	DYNOMITE        = Type(iota)
 	BOLT            = Type(iota)
+	FILES           = Type(iota)
 	COCKROACH       = Type(iota)
 	CACHE           = Type(iota)
 	LEVELDB         = Type(iota)
@@ -33,6 +34,8 @@ func (t Type) String() string {
 		return "rclone"
 	case COCKROACH:
 		return "cockroach"
+	case FILES:
+		return "files"
 	case BOLT:
 		return "bolt"
 	case MINIO: