1 files changed, 30 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/nar-accessor.hh b/third_party/nix/src/libstore/nar-accessor.hh
new file mode 100644
index 000000000000..2871199de16e
--- /dev/null
+++ b/third_party/nix/src/libstore/nar-accessor.hh
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <functional>
+
+#include "fs-accessor.hh"
+
+namespace nix {
+
+/* Return an object that provides access to the contents of a NAR
+   file. */
+ref<FSAccessor> makeNarAccessor(ref<const std::string> nar);
+
+/* Create a NAR accessor from a NAR listing (in the format produced by
+   listNar()). The callback getNarBytes(offset, length) is used by the
+   readFile() method of the accessor to get the contents of files
+   inside the NAR. */
+typedef std::function<std::string(uint64_t, uint64_t)> GetNarBytes;
+
+ref<FSAccessor> makeLazyNarAccessor(
+    const std::string & listing,
+    GetNarBytes getNarBytes);
+
+class JSONPlaceholder;
+
+/* Write a JSON representation of the contents of a NAR (except file
+   contents). */
+void listNar(JSONPlaceholder & res, ref<FSAccessor> accessor,
+    const Path & path, bool recurse);
+
+}