Add --graphml option to the nix-store --query command

This prints the references graph of the store paths in the graphML
format [1]. The graphML format is supported by several graph tools
such as the Python Networkx library or the Apache Thinkerpop project.

[1] http://graphml.graphdrawing.org

1 files changed, 11 insertions, 0 deletions

diff --git a/src/nix-store/graphml.hh b/src/nix-store/graphml.hh
new file mode 100644
index 000000000..b78df1e49
--- /dev/null
+++ b/src/nix-store/graphml.hh
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "types.hh"
+
+namespace nix {
+
+class Store;
+
+void printGraphML(ref<Store> store, const PathSet & roots);
+
+}