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path: root/third_party/nix/src/libutil/archive.hh
#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