object/store/packed: Start the internal/reading split

1 files changed, 20 insertions, 0 deletions

diff --git a/object/store/packed/internal/reading/read_header.go b/object/store/packed/internal/reading/read_header.go
new file mode 100644
index 00000000..d627a6b3
--- /dev/null
+++ b/object/store/packed/internal/reading/read_header.go
@@ -0,0 +1,20 @@
+package reading
+
+import (
+	objectid "codeberg.org/lindenii/furgit/object/id"
+	objecttype "codeberg.org/lindenii/furgit/object/type"
+)
+
+// ReadHeader reads an object's type and declared content size.
+//
+// It resolves header metadata only. It does not verify that the full pack entry
+// payload is readable and does not verify any zlib Adler-32 trailer for
+// compressed entry data.
+func (store *Store) ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) {
+	loc, err := store.lookup(id)
+	if err != nil {
+		return objecttype.TypeInvalid, 0, err
+	}
+
+	return store.resolveHeaderAt(loc)
+}