1 files changed, 116 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 0000000000..87be8a24ea
--- /dev/null
+++ b/third_party/nix/src/libstore/parsed-derivations.cc
@@ -0,0 +1,116 @@
+#include "parsed-derivations.hh"
+
+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 {};
+        else {
+            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 {};
+        else
+            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;
+        else {
+            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;
+        else
+            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 {};
+        else {
+            if (!i->is_array())
+                throw Error("attribute '%s' of derivation '%s' must be a list of strings", name, drvPath);
+            Strings res;
+            for (auto j = i->begin(); j != i->end(); ++j) {
+                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 {};
+        else
+            return tokenizeString<Strings>(i->second);
+    }
+}
+
+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)
+        && !drv.isBuiltin())
+        return false;
+
+    for (auto & feature : getRequiredSystemFeatures())
+        if (!settings.systemFeatures.get().count(feature)) return false;
+
+    return true;
+}
+
+bool ParsedDerivation::willBuildLocally() const
+{
+    return getBoolAttr("preferLocalBuild") && canBuildLocally();
+}
+
+bool ParsedDerivation::substitutesAllowed() const
+{
+    return getBoolAttr("allowSubstitutes", true);
+}
+
+}