backend: refactor backend Connections and HasAtomicReplace into Properties

internal/backend/backend.go

@@ -17,15 +17,12 @@ var ErrNoRepository = fmt.Errorf("repository does not exist")
 // the context package need not be wrapped, as context cancellation is checked
 // separately by the retrying logic.
 type Backend interface {
-	// Connections returns the maximum number of concurrent backend operations.
-	Connections() uint
+	// Properties returns information about the backend
+	Properties() Properties
 
 	// Hasher may return a hash function for calculating a content hash for the backend
 	Hasher() hash.Hash
 
-	// HasAtomicReplace returns whether Save() can atomically replace files
-	HasAtomicReplace() bool
-
 	// Remove removes a File described by h.
 	Remove(ctx context.Context, h Handle) error
 
@@ -92,6 +89,14 @@ type Backend interface {
 	WarmupWait(ctx context.Context, h []Handle) error
 }
 
+type Properties struct {
+	// Connections states the maximum number of concurrent backend operations.
+	Connections uint
+
+	// HasAtomicReplace states whether Save() can atomically replace files
+	HasAtomicReplace bool
+}
+
 type Unwrapper interface {
 	// Unwrap returns the underlying backend or nil if there is none.
 	Unwrap() Backend