Add 'third_party/nix/' from commit 'be66c7a6b24e3c3c6157fd37b86c7203d14acf10' r/724

git-subtree-dir: third_party/nix
git-subtree-mainline: cf8cd640c1adf74a3706efbcb0ea4625da106fb2
git-subtree-split: be66c7a6b24e3c3c6157fd37b86c7203d14acf10

1 files changed, 33 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..64780a6daf40
--- /dev/null
+++ b/third_party/nix/src/libstore/fs-accessor.hh
@@ -0,0 +1,33 @@
+#pragma once
+
+#include "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;
+};
+
+}