objectstore/chain: Add an actual chain object store v0.1.45

1 files changed, 32 insertions, 0 deletions

diff --git a/objectstore/chain/header.go b/objectstore/chain/header.go
new file mode 100644
index 00000000..c1d4692c
--- /dev/null
+++ b/objectstore/chain/header.go
@@ -0,0 +1,32 @@
+package chain
+
+import (
+	"errors"
+	"fmt"
+
+	"codeberg.org/lindenii/furgit/objectid"
+	"codeberg.org/lindenii/furgit/objectstore"
+	"codeberg.org/lindenii/furgit/objecttype"
+)
+
+// ReadHeader reads object header data from the first backend that has it.
+func (chain *Chain) ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) {
+	for i, backend := range chain.backends {
+		if backend == nil {
+			continue
+		}
+
+		ty, size, err := backend.ReadHeader(id)
+		if err == nil {
+			return ty, size, nil
+		}
+
+		if errors.Is(err, objectstore.ErrObjectNotFound) {
+			continue
+		}
+
+		return objecttype.TypeInvalid, 0, fmt.Errorf("objectstore: backend %d read header: %w", i, err)
+	}
+
+	return objecttype.TypeInvalid, 0, objectstore.ErrObjectNotFound
+}