1 files changed, 77 insertions, 0 deletions
diff --git a/third_party/nix/src/libutil/archive.hh b/third_party/nix/src/libutil/archive.hh
new file mode 100644
index 000000000000..396627878541
--- /dev/null
+++ b/third_party/nix/src/libutil/archive.hh
@@ -0,0 +1,77 @@
+#pragma once
+
+#include "libutil/serialise.hh"
+#include "libutil/types.hh"
+
+namespace nix {
+
+/* dumpPath creates a Nix archive of the specified path.  The format
+   is as follows:
+
+   IF path points to a REGULAR FILE:
+     dump(path) = attrs(
+       [ ("type", "regular")
+       , ("contents", contents(path))
+       ])
+
+   IF path points to a DIRECTORY:
+     dump(path) = attrs(
+       [ ("type", "directory")
+       , ("entries", concat(map(f, sort(entries(path)))))
+       ])
+       where f(fn) = attrs(
+         [ ("name", fn)
+         , ("file", dump(path + "/" + fn))
+         ])
+
+   where:
+
+     attrs(as) = concat(map(attr, as)) + encN(0)
+     attrs((a, b)) = encS(a) + encS(b)
+
+     encS(s) = encN(len(s)) + s + (padding until next 64-bit boundary)
+
+     encN(n) = 64-bit little-endian encoding of n.
+
+     contents(path) = the contents of a regular file.
+
+     sort(strings) = lexicographic sort by 8-bit value (strcmp).
+
+     entries(path) = the entries of a directory, without `.' and
+     `..'.
+
+     `+' denotes string concatenation. */
+
+void dumpPath(const Path& path, Sink& sink,
+              PathFilter& filter = defaultPathFilter);
+
+void dumpString(const std::string& s, Sink& sink);
+
+/* FIXME: fix this API, it sucks. */
+struct ParseSink {
+  virtual void createDirectory(const Path& path){};
+
+  virtual void createRegularFile(const Path& path){};
+  virtual void isExecutable(){};
+  virtual void preallocateContents(unsigned long long size){};
+  virtual void receiveContents(unsigned char* data, unsigned int len){};
+
+  virtual void createSymlink(const Path& path, const std::string& target){};
+};
+
+struct TeeSink : ParseSink {
+  TeeSource source;
+
+  explicit TeeSink(Source& source) : source(source) {}
+};
+
+void parseDump(ParseSink& sink, Source& source);
+
+void restorePath(const Path& path, Source& source);
+
+/* Read a NAR from 'source' and write it to 'sink'. */
+void copyNAR(Source& source, Sink& sink);
+
+constexpr std::string_view kNarVersionMagic1 = "nix-archive-1";
+
+}  // namespace nix