1 files changed, 128 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/parsed-derivations.cc b/third_party/nix/src/libstore/parsed-derivations.cc
new file mode 100644
index 000000000000..6989a21fee5c
--- /dev/null
+++ b/third_party/nix/src/libstore/parsed-derivations.cc
@@ -0,0 +1,128 @@
+#include "libstore/parsed-derivations.hh"
+
+#include <absl/strings/str_split.h>
+
+namespace nix {
+
+ParsedDerivation::ParsedDerivation(const Path& drvPath, BasicDerivation& drv)
+    : drvPath(drvPath), drv(drv) {
+  /* Parse the __json attribute, if any. */
+  auto jsonAttr = drv.env.find("__json");
+  if (jsonAttr != drv.env.end()) {
+    try {
+      structuredAttrs = nlohmann::json::parse(jsonAttr->second);
+    } catch (std::exception& e) {
+      throw Error("cannot process __json attribute of '%s': %s", drvPath,
+                  e.what());
+    }
+  }
+}
+
+std::optional<std::string> ParsedDerivation::getStringAttr(
+    const std::string& name) const {
+  if (structuredAttrs) {
+    auto i = structuredAttrs->find(name);
+    if (i == structuredAttrs->end()) {
+      return {};
+    }
+    if (!i->is_string()) {
+      throw Error("attribute '%s' of derivation '%s' must be a string", name,
+                  drvPath);
+    }
+    return i->get<std::string>();
+
+  } else {
+    auto i = drv.env.find(name);
+    if (i == drv.env.end()) {
+      return {};
+    }
+    return i->second;
+  }
+}
+
+bool ParsedDerivation::getBoolAttr(const std::string& name, bool def) const {
+  if (structuredAttrs) {
+    auto i = structuredAttrs->find(name);
+    if (i == structuredAttrs->end()) {
+      return def;
+    }
+    if (!i->is_boolean()) {
+      throw Error("attribute '%s' of derivation '%s' must be a Boolean", name,
+                  drvPath);
+    }
+    return i->get<bool>();
+
+  } else {
+    auto i = drv.env.find(name);
+    if (i == drv.env.end()) {
+      return def;
+    }
+    return i->second == "1";
+  }
+}
+
+std::optional<Strings> ParsedDerivation::getStringsAttr(
+    const std::string& name) const {
+  if (structuredAttrs) {
+    auto i = structuredAttrs->find(name);
+    if (i == structuredAttrs->end()) {
+      return {};
+    }
+    if (!i->is_array()) {
+      throw Error("attribute '%s' of derivation '%s' must be a list of strings",
+                  name, drvPath);
+    }
+    Strings res;
+    for (const auto& j : *i) {
+      if (!j.is_string()) {
+        throw Error(
+            "attribute '%s' of derivation '%s' must be a list of strings", name,
+            drvPath);
+      }
+      res.push_back(j.get<std::string>());
+    }
+    return res;
+
+  } else {
+    auto i = drv.env.find(name);
+    if (i == drv.env.end()) {
+      return {};
+    }
+    return absl::StrSplit(i->second, absl::ByAnyChar(" \t\n\r"),
+                          absl::SkipEmpty());
+  }
+}
+
+StringSet ParsedDerivation::getRequiredSystemFeatures() const {
+  StringSet res;
+  for (auto& i : getStringsAttr("requiredSystemFeatures").value_or(Strings())) {
+    res.insert(i);
+  }
+  return res;
+}
+
+bool ParsedDerivation::canBuildLocally() const {
+  if (drv.platform != settings.thisSystem.get() &&
+      (settings.extraPlatforms.get().count(drv.platform) == 0u) &&
+      !drv.isBuiltin()) {
+    return false;
+  }
+
+  for (auto& feature : getRequiredSystemFeatures()) {
+    if (settings.systemFeatures.get().count(feature) == 0u) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool ParsedDerivation::willBuildLocally() const {
+  return getBoolAttr("preferLocalBuild") && canBuildLocally();
+}
+
+bool ParsedDerivation::substitutesAllowed() const {
+  return getBoolAttr("allowSubstitutes", true);
+}
+
+}  // namespace nix