1 files changed, 17 insertions, 49 deletions

diff --git a/third_party/nix/src/libexpr/attr-set.hh b/third_party/nix/src/libexpr/attr-set.hh
index 795ee2337f..f0b1448ba2 100644
--- a/third_party/nix/src/libexpr/attr-set.hh
+++ b/third_party/nix/src/libexpr/attr-set.hh
@@ -1,8 +1,6 @@
 // This file implements the underlying structure of Nix attribute sets.
 #pragma once
 
-#include <cstddef>
-
 #include <absl/container/btree_map.h>
 #include <gc/gc_allocator.h>
 
@@ -26,75 +24,45 @@ struct Attr {
 
 // Convenience alias for the backing map, with the garbage-collecting
 // allocator explicitly specified.
-using AttributeMap = absl::btree_map<Symbol, Attr, std::less<Symbol>,
-                                     gc_allocator<std::pair<Symbol, Attr>>>;
-
-using AttributeVector =
-    std::vector<std::pair<Symbol, Attr>, gc_allocator<std::pair<Symbol, Attr>>>;
-
-class BindingsIterator : public std::iterator<std::forward_iterator_tag,
-                                              std::pair<const Symbol, Attr>> {
-  friend class Bindings;
-  friend class BTreeBindings;
-  friend class VectorBindings;
-
- public:
-  BindingsIterator() : _iterator(){};
-  BindingsIterator& operator++();
-  BindingsIterator operator++(int);
-  bool operator==(const BindingsIterator& other) const;
-  bool operator!=(const BindingsIterator& other) const;
-  reference operator*() const;
-  pointer operator->() const { return &operator*(); }
-
-  BindingsIterator& operator=(const BindingsIterator& other) {
-    _iterator = other._iterator;
-    return *this;
-  }
-
- protected:
-  explicit BindingsIterator(AttributeMap::iterator&& iterator)
-      : _iterator(iterator){};
-
-  explicit BindingsIterator(AttributeVector::iterator&& iterator)
-      : _iterator(iterator){};
-
- private:
-  std::variant<AttributeMap::iterator, AttributeVector::iterator> _iterator;
-};
+using AttributeMap =
+    absl::btree_map<Symbol, Attr, std::less<Symbol>,
+                    gc_allocator<std::pair<const Symbol, Attr>>>;
 
 class Bindings {
  public:
-  typedef BindingsIterator iterator;
+  typedef AttributeMap::iterator iterator;
 
-  // Allocate a new attribute set with a static capacity that is visible to the
-  // garbage collector.
+  // Allocate a new attribute set that is visible to the garbage
+  // collector.
   static Bindings* NewGC(size_t capacity = 0);
 
   // Return the number of contained elements.
-  virtual size_t size() = 0;
+  size_t size();
 
   // Is this attribute set empty?
-  virtual bool empty() = 0;
+  bool empty();
 
   // Insert, but do not replace, values in the attribute set.
-  virtual void push_back(const Attr& attr) = 0;
+  void push_back(const Attr& attr);
 
   // Look up a specific element of the attribute set.
-  virtual iterator find(const Symbol& name) = 0;
+  iterator find(const Symbol& name);
 
   // TODO
-  virtual iterator begin() = 0;
-  virtual iterator end() = 0;
+  iterator begin();
+  iterator end();
 
   // Merge values from other into this attribute set.
-  virtual void merge(Bindings& other) = 0;
+  void merge(const Bindings& other);
 
   // TODO: can callers just iterate?
-  [[deprecated]] virtual std::vector<const Attr*> lexicographicOrder() = 0;
+  [[deprecated]] std::vector<const Attr*> lexicographicOrder();
 
   // oh no
   friend class EvalState;
+
+ private:
+  AttributeMap attributes_;
 };
 
 }  // namespace nix