1 files changed, 26 insertions, 0 deletions
diff --git a/format/commitgraph/read/open.go b/format/commitgraph/read/open.go
new file mode 100644
index 00000000..9c708b49
--- /dev/null
+++ b/format/commitgraph/read/open.go
@@ -0,0 +1,26 @@
+package read
+
+import (
+	"fmt"
+	"os"
+
+	objectid "codeberg.org/lindenii/furgit/object/id"
+)
+
+// Open opens commit-graph data from one objects root.
+//
+// Open borrows root during construction and does not close it.
+func Open(root *os.Root, algo objectid.Algorithm, mode OpenMode) (*Reader, error) {
+	if algo.Size() == 0 {
+		return nil, objectid.ErrInvalidAlgorithm
+	}
+
+	switch mode {
+	case OpenSingle:
+		return openSingle(root, algo)
+	case OpenChain:
+		return openChain(root, algo)
+	default:
+		return nil, fmt.Errorf("commitgraph: invalid open mode %d", mode)
+	}
+}