1 files changed, 31 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/fs-accessor.hh b/third_party/nix/src/libstore/fs-accessor.hh
new file mode 100644
index 000000000000..1bc1373dcb2f
--- /dev/null
+++ b/third_party/nix/src/libstore/fs-accessor.hh
@@ -0,0 +1,31 @@
+#pragma once
+
+#include "libutil/types.hh"
+
+namespace nix {
+
+/* An abstract class for accessing a filesystem-like structure, such
+   as a (possibly remote) Nix store or the contents of a NAR file. */
+class FSAccessor {
+ public:
+  enum Type { tMissing, tRegular, tSymlink, tDirectory };
+
+  struct Stat {
+    Type type = tMissing;
+    uint64_t fileSize = 0;      // regular files only
+    bool isExecutable = false;  // regular files only
+    uint64_t narOffset = 0;     // regular files only
+  };
+
+  virtual ~FSAccessor() {}
+
+  virtual Stat stat(const Path& path) = 0;
+
+  virtual StringSet readDirectory(const Path& path) = 0;
+
+  virtual std::string readFile(const Path& path) = 0;
+
+  virtual std::string readLink(const Path& path) = 0;
+};
+
+}  // namespace nix