1 files changed, 61 insertions, 0 deletions
diff --git a/object/store/packed/delta_resolve_chain.go b/object/store/packed/delta_resolve_chain.go
new file mode 100644
index 00000000..6347ee41
--- /dev/null
+++ b/object/store/packed/delta_resolve_chain.go
@@ -0,0 +1,61 @@
+package packed
+
+import (
+	"fmt"
+
+	deltaapply "codeberg.org/lindenii/furgit/format/packfile/delta/apply"
+	objecttype "codeberg.org/lindenii/furgit/object/type"
+)
+
+// deltaResolveChain resolves one object chain into content bytes.
+func (store *Store) deltaResolveChain(chain deltaChain, declaredSize int64) (objecttype.Type, []byte, error) {
+	ty, out, nextDelta, err := store.deltaResolveChainStart(chain)
+	if err != nil {
+		return objecttype.TypeInvalid, nil, err
+	}
+
+	for i := nextDelta; i >= 0; i-- {
+		node := chain.deltas[i]
+
+		pack, err := store.openPack(node.loc.packName)
+		if err != nil {
+			return objecttype.TypeInvalid, nil, err
+		}
+
+		delta, err := inflateAt(pack, node.dataOffset, -1)
+		if err != nil {
+			return objecttype.TypeInvalid, nil, err
+		}
+
+		out, err = deltaapply.Apply(out, delta)
+		if err != nil {
+			return objecttype.TypeInvalid, nil, err
+		}
+
+		store.cacheMu.Lock()
+		store.deltaCache.add(
+			deltaBaseKey{packName: node.loc.packName, offset: node.loc.offset},
+			ty,
+			out,
+		)
+		store.cacheMu.Unlock()
+	}
+
+	if int64(len(out)) != declaredSize {
+		return objecttype.TypeInvalid, nil, fmt.Errorf(
+			"objectstore/packed: resolved content size mismatch: got %d want %d",
+			len(out),
+			declaredSize,
+		)
+	}
+
+	if ty != chain.baseType {
+		return objecttype.TypeInvalid, nil, fmt.Errorf(
+			"objectstore/packed: resolved content type mismatch: got %d want %d",
+			ty,
+			chain.baseType,
+		)
+	}
+
+	return ty, out, nil
+}