1 files changed, 100 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/value-to-json.cc b/third_party/nix/src/libexpr/value-to-json.cc
new file mode 100644
index 000000000000..5fe8570adeb4
--- /dev/null
+++ b/third_party/nix/src/libexpr/value-to-json.cc
@@ -0,0 +1,100 @@
+#include "value-to-json.hh"
+#include "json.hh"
+#include "eval-inline.hh"
+#include "util.hh"
+
+#include <cstdlib>
+#include <iomanip>
+
+
+namespace nix {
+
+void printValueAsJSON(EvalState & state, bool strict,
+    Value & v, JSONPlaceholder & out, PathSet & context)
+{
+    checkInterrupt();
+
+    if (strict) state.forceValue(v);
+
+    switch (v.type) {
+
+        case tInt:
+            out.write(v.integer);
+            break;
+
+        case tBool:
+            out.write(v.boolean);
+            break;
+
+        case tString:
+            copyContext(v, context);
+            out.write(v.string.s);
+            break;
+
+        case tPath:
+            out.write(state.copyPathToStore(context, v.path));
+            break;
+
+        case tNull:
+            out.write(nullptr);
+            break;
+
+        case tAttrs: {
+            auto maybeString = state.tryAttrsToString(noPos, v, context, false, false);
+            if (maybeString) {
+                out.write(*maybeString);
+                break;
+            }
+            auto i = v.attrs->find(state.sOutPath);
+            if (i == v.attrs->end()) {
+                auto obj(out.object());
+                StringSet names;
+                for (auto & j : *v.attrs)
+                    names.insert(j.name);
+                for (auto & j : names) {
+                    Attr & a(*v.attrs->find(state.symbols.create(j)));
+                    auto placeholder(obj.placeholder(j));
+                    printValueAsJSON(state, strict, *a.value, placeholder, context);
+                }
+            } else
+                printValueAsJSON(state, strict, *i->value, out, context);
+            break;
+        }
+
+        case tList1: case tList2: case tListN: {
+            auto list(out.list());
+            for (unsigned int n = 0; n < v.listSize(); ++n) {
+                auto placeholder(list.placeholder());
+                printValueAsJSON(state, strict, *v.listElems()[n], placeholder, context);
+            }
+            break;
+        }
+
+        case tExternal:
+            v.external->printValueAsJSON(state, strict, out, context);
+            break;
+
+        case tFloat:
+            out.write(v.fpoint);
+            break;
+
+        default:
+            throw TypeError(format("cannot convert %1% to JSON") % showType(v));
+    }
+}
+
+void printValueAsJSON(EvalState & state, bool strict,
+    Value & v, std::ostream & str, PathSet & context)
+{
+    JSONPlaceholder out(str);
+    printValueAsJSON(state, strict, v, out, context);
+}
+
+void ExternalValueBase::printValueAsJSON(EvalState & state, bool strict,
+    JSONPlaceholder & out, PathSet & context) const
+{
+    throw TypeError(format("cannot convert %1% to JSON") % showType());
+}
+
+
+}