refactor: storage interface

pkg/storage/fs/fs.go

@@ -1,27 +1,30 @@
-// fs implements Storage on filesystem
+// fs implements galaxy/storage.Storage with filesystem
 package fs
 
 import (
-	"errors"
+	"fmt"
 	"galaxy/util"
 )
 
-type fs struct {
-	rootPath string
+type fsStorage struct {
+	path string
 }
 
-// NewStorage returns on-filesystem implementation of the "galaxy/storage.Storage" with root located at rootPath.
+// NewFS returns on-filesystem implementation of the "galaxy/storage.Storage" with root located at rootPath.
 // rootPath must me a directory and has write access to the current user. If initial checks failed, return nil and non-nil error.
-func NewFS(rootPath string) (*fs, error) {
-	ok, err := util.Writable(rootPath)
-	if err != nil {
-		return nil, err
+func NewStorage(path string) (*fsStorage, error) {
+	if ok, err := util.PathExists(path, true); err != nil {
+		return nil, fmt.Errorf("new storage: check path %q exists: %w", path, err)
+	} else if !ok {
+		return nil, fmt.Errorf("new storage: path %q does not exists", path)
 	}
-	if !ok {
-		return nil, errors.New("user does not have write permissions to the storage root")
+	if ok, err := util.Writable(path); err != nil {
+		return nil, fmt.Errorf("new storage: check path %q writable: %w", path, err)
+	} else if !ok {
+		return nil, fmt.Errorf("new storage: path %q is not writable", path)
 	}
-	s := &fs{
-		rootPath: rootPath,
+	s := &fsStorage{
+		path: path,
 	}
 	return s, nil
 }