added ID type

internal/types/id.go

@@ -0,0 +1,64 @@
+package types
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+var (
+	idRegex = regexp.MustCompile(`(.*?)(@(.*))?:(.*)`)
+)
+
+// ID an id of a file consists of at least a Bucket and a Key. Version is optional.
+// Can also be used as an ID for a directory. When the key ends with "/" it is treated as dir.
+type ID struct {
+	Bucket  string // Name of the bucket
+	Key     string // Key of the object
+	Version string // Version of the object. For now we ignore it
+}
+
+// String Return String representation of an ID
+// Looks like this: "bucketName@version:/id/of/obj" or "bucketName:/id/of/obj"
+func (i *ID) String() string {
+	i.Normalize()
+	if i.Version == "" {
+		return fmt.Sprintf("%s:%s", i.Bucket, i.Key)
+	} else {
+		return fmt.Sprintf("%s@%s:%s", i.Bucket, i.Version, i.Key)
+	}
+}
+
+// Normalize normalzes the key to have a "/" prefix
+func (i *ID) Normalize() {
+	if !strings.HasPrefix(i.Key, "/") {
+		i.Key = "/" + i.Key
+	}
+}
+
+// Valid checks if bucket and key is not empty
+func (i *ID) Valid() bool {
+	return i.Bucket != "" && i.Key != ""
+}
+
+// ParseID parses a string to an ID. Null if invalid
+func ParseID(id string) *ID {
+	match := idRegex.FindStringSubmatch(id)
+	if match == nil {
+		return nil
+	}
+
+	rtn := &ID{
+		Bucket:  match[1],
+		Version: match[3],
+		Key:     match[4],
+	}
+
+	if !rtn.Valid() {
+		return nil
+	}
+
+	rtn.Normalize()
+
+	return rtn
+}