1 files changed, 111 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/export-import.cc b/third_party/nix/src/libstore/export-import.cc
new file mode 100644
index 0000000000..8e93144339
--- /dev/null
+++ b/third_party/nix/src/libstore/export-import.cc
@@ -0,0 +1,111 @@
+#include <algorithm>
+
+#include "libstore/store-api.hh"
+#include "libstore/worker-protocol.hh"
+#include "libutil/archive.hh"
+
+namespace nix {
+
+struct HashAndWriteSink : Sink {
+  Sink& writeSink;
+  HashSink hashSink;
+  explicit HashAndWriteSink(Sink& writeSink)
+      : writeSink(writeSink), hashSink(htSHA256) {}
+  void operator()(const unsigned char* data, size_t len) override {
+    writeSink(data, len);
+    hashSink(data, len);
+  }
+  Hash currentHash() { return hashSink.currentHash().first; }
+};
+
+void Store::exportPaths(const Paths& paths, Sink& sink) {
+  Paths sorted = topoSortPaths(PathSet(paths.begin(), paths.end()));
+  std::reverse(sorted.begin(), sorted.end());
+
+  std::string doneLabel("paths exported");
+  // logger->incExpected(doneLabel, sorted.size());
+
+  for (auto& path : sorted) {
+    // Activity act(*logger, lvlInfo, format("exporting path '%s'") % path);
+    sink << 1;
+    exportPath(path, sink);
+    // logger->incProgress(doneLabel);
+  }
+
+  sink << 0;
+}
+
+void Store::exportPath(const Path& path, Sink& sink) {
+  auto info = queryPathInfo(path);
+
+  HashAndWriteSink hashAndWriteSink(sink);
+
+  narFromPath(path, hashAndWriteSink);
+
+  /* Refuse to export paths that have changed.  This prevents
+     filesystem corruption from spreading to other machines.
+     Don't complain if the stored hash is zero (unknown). */
+  Hash hash = hashAndWriteSink.currentHash();
+  if (hash != info->narHash && info->narHash != Hash(info->narHash.type)) {
+    throw Error(format("hash of path '%1%' has changed from '%2%' to '%3%'!") %
+                path % info->narHash.to_string() % hash.to_string());
+  }
+
+  hashAndWriteSink << exportMagic << path << info->references << info->deriver
+                   << 0;
+}
+
+Paths Store::importPaths(Source& source,
+                         const std::shared_ptr<FSAccessor>& accessor,
+                         CheckSigsFlag checkSigs) {
+  Paths res;
+  while (true) {
+    auto n = readNum<uint64_t>(source);
+    if (n == 0) {
+      break;
+    }
+    if (n != 1) {
+      throw Error(
+          "input doesn't look like something created by 'nix-store --export'");
+    }
+
+    /* Extract the NAR from the source. */
+    TeeSink tee(source);
+    parseDump(tee, tee.source);
+
+    uint32_t magic = readInt(source);
+    if (magic != exportMagic) {
+      throw Error("Nix archive cannot be imported; wrong format");
+    }
+
+    ValidPathInfo info;
+
+    info.path = readStorePath(*this, source);
+
+    // Activity act(*logger, lvlInfo, format("importing path '%s'") %
+    // info.path);
+
+    info.references = readStorePaths<PathSet>(*this, source);
+
+    info.deriver = readString(source);
+    if (!info.deriver.empty()) {
+      assertStorePath(info.deriver);
+    }
+
+    info.narHash = hashString(htSHA256, *tee.source.data);
+    info.narSize = tee.source.data->size();
+
+    // Ignore optional legacy signature.
+    if (readInt(source) == 1) {
+      readString(source);
+    }
+
+    addToStore(info, tee.source.data, NoRepair, checkSigs, accessor);
+
+    res.push_back(info.path);
+  }
+
+  return res;
+}
+
+}  // namespace nix