1 files changed, 27 insertions, 13 deletions

diff --git a/src/libexpr/attr-set.cc b/src/libexpr/attr-set.cc
index b6091c955..52ac47e9b 100644
--- a/src/libexpr/attr-set.cc
+++ b/src/libexpr/attr-set.cc
@@ -7,26 +7,19 @@
 namespace nix {
 
 
+
 /* Allocate a new array of attributes for an attribute set with a specific
    capacity. The space is implicitly reserved after the Bindings
    structure. */
 Bindings * EvalState::allocBindings(size_t capacity)
 {
+    if (capacity == 0)
+        return &emptyBindings;
     if (capacity > std::numeric_limits<Bindings::size_t>::max())
         throw Error("attribute set of size %d is too big", capacity);
-    return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity)) Bindings((Bindings::size_t) capacity);
-}
-
-
-void EvalState::mkAttrs(Value & v, size_t capacity)
-{
-    if (capacity == 0) {
-        v = vEmptySet;
-        return;
-    }
-    v.mkAttrs(allocBindings(capacity));
     nrAttrsets++;
     nrAttrsInAttrsets += capacity;
+    return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity)) Bindings((Bindings::size_t) capacity);
 }
 
 
@@ -41,15 +34,36 @@ Value * EvalState::allocAttr(Value & vAttrs, const Symbol & name)
 }
 
 
-Value * EvalState::allocAttr(Value & vAttrs, const std::string & name)
+Value * EvalState::allocAttr(Value & vAttrs, std::string_view name)
 {
     return allocAttr(vAttrs, symbols.create(name));
 }
 
 
+Value & BindingsBuilder::alloc(const Symbol & name, ptr<Pos> pos)
+{
+    auto value = state.allocValue();
+    bindings->push_back(Attr(name, value, pos));
+    return *value;
+}
+
+
+Value & BindingsBuilder::alloc(std::string_view name, ptr<Pos> pos)
+{
+    return alloc(state.symbols.create(name), pos);
+}
+
+
 void Bindings::sort()
 {
-    std::sort(begin(), end());
+    if (size_) std::sort(begin(), end());
+}
+
+
+Value & Value::mkAttrs(BindingsBuilder & bindings)
+{
+    mkAttrs(bindings.finish());
+    return *this;
 }