1 files changed, 520 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/derivations.cc b/third_party/nix/src/libstore/derivations.cc
new file mode 100644
index 000000000000..9c344502f386
--- /dev/null
+++ b/third_party/nix/src/libstore/derivations.cc
@@ -0,0 +1,520 @@
+#include "libstore/derivations.hh"
+
+#include <absl/strings/match.h>
+#include <absl/strings/str_split.h>
+#include <absl/strings/string_view.h>
+#include <glog/logging.h>
+
+#include "libproto/worker.pb.h"
+#include "libstore/fs-accessor.hh"
+#include "libstore/globals.hh"
+#include "libstore/store-api.hh"
+#include "libstore/worker-protocol.hh"
+#include "libutil/istringstream_nocopy.hh"
+#include "libutil/util.hh"
+
+namespace nix {
+
+// TODO(#statusor): looks like easy absl::Status conversion
+void DerivationOutput::parseHashInfo(bool& recursive, Hash& hash) const {
+  recursive = false;
+  std::string algo = hashAlgo;
+
+  if (std::string(algo, 0, 2) == "r:") {
+    recursive = true;
+    algo = std::string(algo, 2);
+  }
+
+  HashType hashType = parseHashType(algo);
+  if (hashType == htUnknown) {
+    throw Error(format("unknown hash algorithm '%1%'") % algo);
+  }
+
+  auto hash_ = Hash::deserialize(this->hash, hashType);
+  hash = Hash::unwrap_throw(hash_);
+}
+
+nix::proto::Derivation_DerivationOutput DerivationOutput::to_proto() const {
+  nix::proto::Derivation_DerivationOutput result;
+  result.mutable_path()->set_path(path);
+  result.set_hash_algo(hashAlgo);
+  result.set_hash(hash);
+  return result;
+}
+
+BasicDerivation BasicDerivation::from_proto(
+    const nix::proto::Derivation* proto_derivation) {
+  BasicDerivation result;
+  result.platform = proto_derivation->platform();
+  result.builder = proto_derivation->builder().path();
+
+  for (auto [k, v] : proto_derivation->outputs()) {
+    result.outputs.emplace(k, v);
+  }
+
+  result.inputSrcs.insert(proto_derivation->input_sources().paths().begin(),
+                          proto_derivation->input_sources().paths().end());
+
+  result.args.insert(result.args.end(), proto_derivation->args().begin(),
+                     proto_derivation->args().end());
+
+  for (auto [k, v] : proto_derivation->env()) {
+    result.env.emplace(k, v);
+  }
+
+  return result;
+}
+
+nix::proto::Derivation BasicDerivation::to_proto() const {
+  nix::proto::Derivation result;
+  for (const auto& [key, output] : outputs) {
+    result.mutable_outputs()->insert({key, output.to_proto()});
+  }
+  for (const auto& input_src : inputSrcs) {
+    *result.mutable_input_sources()->add_paths() = input_src;
+  }
+  result.set_platform(platform);
+  result.mutable_builder()->set_path(builder);
+  for (const auto& arg : args) {
+    result.add_args(arg);
+  }
+
+  for (const auto& [key, value] : env) {
+    result.mutable_env()->insert({key, value});
+  }
+
+  return result;
+}
+
+Path BasicDerivation::findOutput(const std::string& id) const {
+  auto i = outputs.find(id);
+  if (i == outputs.end()) {
+    throw Error(format("derivation has no output '%1%'") % id);
+  }
+  return i->second.path;
+}
+
+bool BasicDerivation::isBuiltin() const {
+  return std::string(builder, 0, 8) == "builtin:";
+}
+
+Path writeDerivation(const ref<Store>& store, const Derivation& drv,
+                     const std::string& name, RepairFlag repair) {
+  PathSet references;
+  references.insert(drv.inputSrcs.begin(), drv.inputSrcs.end());
+  for (auto& i : drv.inputDrvs) {
+    references.insert(i.first);
+  }
+  /* Note that the outputs of a derivation are *not* references
+     (that can be missing (of course) and should not necessarily be
+     held during a garbage collection). */
+  std::string suffix = name + drvExtension;
+  std::string contents = drv.unparse();
+  return settings.readOnlyMode
+             ? store->computeStorePathForText(suffix, contents, references)
+             : store->addTextToStore(suffix, contents, references, repair);
+}
+
+/* Read string `s' from stream `str'. */
+static void expect(std::istream& str, const std::string& s) {
+  char s2[s.size()];
+  str.read(s2, s.size());
+  if (std::string(s2, s.size()) != s) {
+    throw FormatError(format("expected string '%1%'") % s);
+  }
+}
+
+/* Read a C-style string from stream `str'. */
+static std::string parseString(std::istream& str) {
+  std::string res;
+  expect(str, "\"");
+  int c;
+  while ((c = str.get()) != '"' && c != EOF) {
+    if (c == '\\') {
+      c = str.get();
+      if (c == 'n') {
+        res += '\n';
+      } else if (c == 'r') {
+        res += '\r';
+      } else if (c == 't') {
+        res += '\t';
+      } else if (c == EOF) {
+        throw FormatError("unexpected EOF while parsing C-style escape");
+      } else {
+        res += static_cast<char>(c);
+      }
+    } else {
+      res += static_cast<char>(c);
+    }
+  }
+  return res;
+}
+
+static Path parsePath(std::istream& str) {
+  std::string s = parseString(str);
+  if (s.empty() || s[0] != '/') {
+    throw FormatError(format("bad path '%1%' in derivation") % s);
+  }
+  return s;
+}
+
+static bool endOfList(std::istream& str) {
+  if (str.peek() == ',') {
+    str.get();
+    return false;
+  }
+  if (str.peek() == ']') {
+    str.get();
+    return true;
+  }
+  return false;
+}
+
+static StringSet parseStrings(std::istream& str, bool arePaths) {
+  StringSet res;
+  while (!endOfList(str)) {
+    res.insert(arePaths ? parsePath(str) : parseString(str));
+  }
+  return res;
+}
+
+Derivation parseDerivation(const std::string& s) {
+  Derivation drv;
+  istringstream_nocopy str(s);
+  expect(str, "Derive([");
+
+  /* Parse the list of outputs. */
+  while (!endOfList(str)) {
+    DerivationOutput out;
+    expect(str, "(");
+    std::string id = parseString(str);
+    expect(str, ",");
+    out.path = parsePath(str);
+    expect(str, ",");
+    out.hashAlgo = parseString(str);
+    expect(str, ",");
+    out.hash = parseString(str);
+    expect(str, ")");
+    drv.outputs[id] = out;
+  }
+
+  /* Parse the list of input derivations. */
+  expect(str, ",[");
+  while (!endOfList(str)) {
+    expect(str, "(");
+    Path drvPath = parsePath(str);
+    expect(str, ",[");
+    drv.inputDrvs[drvPath] = parseStrings(str, false);
+    expect(str, ")");
+  }
+
+  expect(str, ",[");
+  drv.inputSrcs = parseStrings(str, true);
+  expect(str, ",");
+  drv.platform = parseString(str);
+  expect(str, ",");
+  drv.builder = parseString(str);
+
+  /* Parse the builder arguments. */
+  expect(str, ",[");
+  while (!endOfList(str)) {
+    drv.args.push_back(parseString(str));
+  }
+
+  /* Parse the environment variables. */
+  expect(str, ",[");
+  while (!endOfList(str)) {
+    expect(str, "(");
+    std::string name = parseString(str);
+    expect(str, ",");
+    std::string value = parseString(str);
+    expect(str, ")");
+    drv.env[name] = value;
+  }
+
+  expect(str, ")");
+  return drv;
+}
+
+Derivation readDerivation(const Path& drvPath) {
+  try {
+    return parseDerivation(readFile(drvPath));
+  } catch (FormatError& e) {
+    throw Error(format("error parsing derivation '%1%': %2%") % drvPath %
+                e.msg());
+  }
+}
+
+Derivation Store::derivationFromPath(const Path& drvPath) {
+  assertStorePath(drvPath);
+  ensurePath(drvPath);
+  auto accessor = getFSAccessor();
+  try {
+    return parseDerivation(accessor->readFile(drvPath));
+  } catch (FormatError& e) {
+    throw Error(format("error parsing derivation '%1%': %2%") % drvPath %
+                e.msg());
+  }
+}
+
+const char* findChunk(const char* begin) {
+  while (*begin != 0 && *begin != '\"' && *begin != '\\' && *begin != '\n' &&
+         *begin != '\r' && *begin != '\t') {
+    begin++;
+  }
+
+  return begin;
+}
+
+static void printString(std::string& res, const std::string& s) {
+  res += '"';
+
+  const char* it = s.c_str();
+  while (*it != 0) {
+    const char* end = findChunk(it);
+    std::copy(it, end, std::back_inserter(res));
+
+    it = end;
+
+    switch (*it) {
+      case '"':
+      case '\\':
+        res += "\\";
+        res += *it;
+        break;
+      case '\n':
+        res += "\\n";
+        break;
+      case '\r':
+        res += "\\r";
+        break;
+      case '\t':
+        res += "\\t";
+        break;
+      default:
+        continue;
+    }
+
+    it++;
+  }
+
+  res += '"';
+}
+
+template <class ForwardIterator>
+static void printStrings(std::string& res, ForwardIterator i,
+                         ForwardIterator j) {
+  res += '[';
+  bool first = true;
+  for (; i != j; ++i) {
+    if (first) {
+      first = false;
+    } else {
+      res += ',';
+    }
+    printString(res, *i);
+  }
+  res += ']';
+}
+
+std::string Derivation::unparse() const {
+  std::string s;
+  s.reserve(65536);
+  s += "Derive([";
+
+  bool first = true;
+  for (auto& i : outputs) {
+    if (first) {
+      first = false;
+    } else {
+      s += ',';
+    }
+    s += '(';
+    printString(s, i.first);
+    s += ',';
+    printString(s, i.second.path);
+    s += ',';
+    printString(s, i.second.hashAlgo);
+    s += ',';
+    printString(s, i.second.hash);
+    s += ')';
+  }
+
+  s += "],[";
+  first = true;
+  for (auto& i : inputDrvs) {
+    if (first) {
+      first = false;
+    } else {
+      s += ',';
+    }
+    s += '(';
+    printString(s, i.first);
+    s += ',';
+    printStrings(s, i.second.begin(), i.second.end());
+    s += ')';
+  }
+
+  s += "],";
+  printStrings(s, inputSrcs.begin(), inputSrcs.end());
+
+  s += ',';
+  printString(s, platform);
+  s += ',';
+  printString(s, builder);
+  s += ',';
+  printStrings(s, args.begin(), args.end());
+
+  s += ",[";
+  first = true;
+  for (auto& i : env) {
+    if (first) {
+      first = false;
+    } else {
+      s += ',';
+    }
+    s += '(';
+    printString(s, i.first);
+    s += ',';
+    printString(s, i.second);
+    s += ')';
+  }
+
+  s += "])";
+
+  return s;
+}
+
+bool isDerivation(const std::string& fileName) {
+  return absl::EndsWith(fileName, drvExtension);
+}
+
+bool BasicDerivation::isFixedOutput() const {
+  return outputs.size() == 1 && outputs.begin()->first == "out" &&
+         !outputs.begin()->second.hash.empty();
+}
+
+DrvHashes drvHashes;
+
+/* Returns the hash of a derivation modulo fixed-output
+   subderivations.  A fixed-output derivation is a derivation with one
+   output (`out') for which an expected hash and hash algorithm are
+   specified (using the `outputHash' and `outputHashAlgo'
+   attributes).  We don't want changes to such derivations to
+   propagate upwards through the dependency graph, changing output
+   paths everywhere.
+
+   For instance, if we change the url in a call to the `fetchurl'
+   function, we do not want to rebuild everything depending on it
+   (after all, (the hash of) the file being downloaded is unchanged).
+   So the *output paths* should not change.  On the other hand, the
+   *derivation paths* should change to reflect the new dependency
+   graph.
+
+   That's what this function does: it returns a hash which is just the
+   hash of the derivation ATerm, except that any input derivation
+   paths have been replaced by the result of a recursive call to this
+   function, and that for fixed-output derivations we return a hash of
+   its output path. */
+Hash hashDerivationModulo(Store& store, Derivation drv) {
+  /* Return a fixed hash for fixed-output derivations. */
+  if (drv.isFixedOutput()) {
+    auto i = drv.outputs.begin();
+    return hashString(htSHA256, "fixed:out:" + i->second.hashAlgo + ":" +
+                                    i->second.hash + ":" + i->second.path);
+  }
+
+  /* For other derivations, replace the inputs paths with recursive
+     calls to this function.*/
+  DerivationInputs inputs2;
+  for (auto& i : drv.inputDrvs) {
+    Hash h = drvHashes[i.first];
+    if (!h) {
+      assert(store.isValidPath(i.first));
+      Derivation drv2 = readDerivation(store.toRealPath(i.first));
+      h = hashDerivationModulo(store, drv2);
+      drvHashes[i.first] = h;
+    }
+    inputs2[h.to_string(Base16, false)] = i.second;
+  }
+  drv.inputDrvs = inputs2;
+
+  return hashString(htSHA256, drv.unparse());
+}
+
+DrvPathWithOutputs parseDrvPathWithOutputs(absl::string_view path) {
+  auto pos = path.find('!');
+  if (pos == absl::string_view::npos) {
+    return DrvPathWithOutputs(path, std::set<std::string>());
+  }
+
+  return DrvPathWithOutputs(
+      path.substr(0, pos),
+      absl::StrSplit(path.substr(pos + 1), absl::ByChar(','),
+                     absl::SkipEmpty()));
+}
+
+Path makeDrvPathWithOutputs(const Path& drvPath,
+                            const std::set<std::string>& outputs) {
+  return outputs.empty() ? drvPath
+                         : drvPath + "!" + concatStringsSep(",", outputs);
+}
+
+bool wantOutput(const std::string& output,
+                const std::set<std::string>& wanted) {
+  return wanted.empty() || wanted.find(output) != wanted.end();
+}
+
+PathSet BasicDerivation::outputPaths() const {
+  PathSet paths;
+  for (auto& i : outputs) {
+    paths.insert(i.second.path);
+  }
+  return paths;
+}
+
+Source& readDerivation(Source& in, Store& store, BasicDerivation& drv) {
+  drv.outputs.clear();
+  auto nr = readNum<size_t>(in);
+  for (size_t n = 0; n < nr; n++) {
+    auto name = readString(in);
+    DerivationOutput o;
+    in >> o.path >> o.hashAlgo >> o.hash;
+    store.assertStorePath(o.path);
+    drv.outputs[name] = o;
+  }
+
+  drv.inputSrcs = readStorePaths<PathSet>(store, in);
+  in >> drv.platform >> drv.builder;
+  drv.args = readStrings<Strings>(in);
+
+  nr = readNum<size_t>(in);
+  for (size_t n = 0; n < nr; n++) {
+    auto key = readString(in);
+    auto value = readString(in);
+    drv.env[key] = value;
+  }
+
+  return in;
+}
+
+Sink& operator<<(Sink& out, const BasicDerivation& drv) {
+  out << drv.outputs.size();
+  for (auto& i : drv.outputs) {
+    out << i.first << i.second.path << i.second.hashAlgo << i.second.hash;
+  }
+  out << drv.inputSrcs << drv.platform << drv.builder << drv.args;
+  out << drv.env.size();
+  for (auto& i : drv.env) {
+    out << i.first << i.second;
+  }
+  return out;
+}
+
+std::string hashPlaceholder(const std::string& outputName) {
+  // FIXME: memoize?
+  return "/" + hashString(htSHA256, "nix-output:" + outputName)
+                   .to_string(Base32, false);
+}
+
+}  // namespace nix