1 files changed, 72 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/common-eval-args.cc b/third_party/nix/src/libexpr/common-eval-args.cc
new file mode 100644
index 0000000000..f63d3f8276
--- /dev/null
+++ b/third_party/nix/src/libexpr/common-eval-args.cc
@@ -0,0 +1,72 @@
+#include "libexpr/common-eval-args.hh"
+
+#include "libexpr/eval.hh"
+#include "libmain/shared.hh"
+#include "libstore/download.hh"
+#include "libutil/util.hh"
+
+namespace nix {
+
+MixEvalArgs::MixEvalArgs() {
+  mkFlag()
+      .longName("arg")
+      .description("argument to be passed to Nix functions")
+      .labels({"name", "expr"})
+      .handler([&](std::vector<std::string> ss) {
+        auto_args_[ss[0]] = std::make_pair(kArgTypeExpr, ss[1]);
+      });
+
+  mkFlag()
+      .longName("argstr")
+      .description("string-valued argument to be passed to Nix functions")
+      .labels({"name", "string"})
+      .handler([&](std::vector<std::string> ss) {
+        auto_args_[ss[0]] = std::make_pair(kArgTypeString, ss[1]);
+      });
+
+  mkFlag()
+      .shortName('I')
+      .longName("include")
+      .description(
+          "add a path to the list of locations used to look up <...> file "
+          "names")
+      .label("path")
+      .handler([&](const std::string& s) { searchPath.push_back(s); });
+}
+
+std::unique_ptr<Bindings> MixEvalArgs::getAutoArgs(EvalState& state) {
+  auto res = Bindings::New(auto_args_.size());
+  for (auto& [arg, arg_value] : auto_args_) {
+    Value* v = state.allocValue();
+    switch (arg_value.first) {
+      case kArgTypeExpr: {
+        state.mkThunk_(
+            *v, state.parseExprFromString(arg_value.second, absPath(".")));
+        break;
+      }
+      case kArgTypeString: {
+        mkString(*v, arg_value.second);
+        break;
+      }
+    }
+
+    res->push_back(Attr(state.symbols.Create(arg), v));
+  }
+  return res;
+}
+
+Path lookupFileArg(EvalState& state, std::string s) {
+  if (isUri(s)) {
+    CachedDownloadRequest request(s);
+    request.unpack = true;
+    return getDownloader()->downloadCached(state.store, request).path;
+  }
+  if (s.size() > 2 && s.at(0) == '<' && s.at(s.size() - 1) == '>') {
+    Path p = s.substr(1, s.size() - 2);
+    return state.findFile(p);
+  } else {
+    return absPath(s);
+  }
+}
+
+}  // namespace nix