ref: Create a storage interface

This `Storage` interface will define all the interactions with the
storage system. For now I plan to support native file system through
go's standard library and Nextcloud through *webdav*. So this is the
first step in that direction.

1 files changed, 30 insertions, 0 deletions

diff --git a/storage/storage.go b/storage/storage.go
new file mode 100644
index 0000000..b788efb
--- /dev/null
+++ b/storage/storage.go
@@ -0,0 +1,30 @@
+package storage
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"io"
+)
+
+type WalkMode int
+
+const (
+	Folder WalkMode = iota
+	File
+	FileFolder
+)
+
+type Storage interface {
+	Walk(path string, walkMode WalkMode) <-chan string
+	Get(path string) (io.Reader, error)
+}
+
+func CalculateSHA256(r io.Reader) (string, error) {
+	h := sha256.New()
+	if _, err := io.Copy(h, r); err != nil {
+		return "", err
+	}
+
+	return fmt.Sprintf("%x", h.Sum(nil)), nil
+
+}