Review fixes.

3 files changed, 50 insertions, 18 deletions

diff --git a/base/base_tests/stl_helpers_test.cpp b/base/base_tests/stl_helpers_test.cpp
index 029df6af98..71462cfbaf 100644
--- a/base/base_tests/stl_helpers_test.cpp
+++ b/base/base_tests/stl_helpers_test.cpp
@@ -125,4 +125,28 @@ UNIT_TEST(SortUnique_VectorTest)
   TestSortUnique<vector>();
   TestSortUnique<deque>();
 }
+
+UNIT_TEST(IgnoreFirstArgument)
+{
+  {
+    int s = 0;
+    auto f1 = [&](int a, int b) { s += a + b; };
+    auto f2 = [&](int a, int b) { s -= a + b; };
+    auto f3 = my::MakeIgnoreFirstArgument(f2);
+
+    f1(2, 3);
+    TEST_EQUAL(s, 5, ());
+    f3(1, 2, 3);
+    TEST_EQUAL(s, 0, ());
+  }
+
+  {
+    auto f1 = [](int a, int b) -> int { return a + b; };
+    auto f2 = my::MakeIgnoreFirstArgument(f1);
+
+    auto const x = f1(2, 3);
+    auto const y = f2("ignored", 2, 3);
+    TEST_EQUAL(x, y, ());
+  }
+}
 }  // namespace
diff --git a/base/mem_trie.hpp b/base/mem_trie.hpp
index 354675663d..fdd35af365 100644
--- a/base/mem_trie.hpp
+++ b/base/mem_trie.hpp
@@ -59,16 +59,6 @@ public:
       ForEachInNode(*root, prefix, std::forward<ToDo>(toDo));
   }
 
-  // Calls |toDo| for each value in the node that is reachable
-  // by |prefix| from the trie root. Does nothing if such node does
-  // not exist.
-  template <typename ToDo>
-  void ForEachValueInNode(String const & prefix, ToDo && toDo) const
-  {
-    if (auto const * root = MoveTo(prefix))
-      ForEachValueInNode(*root, std::forward<ToDo>(toDo));
-  }
-
   // Calls |toDo| for each key-value pair in a subtree that is
   // reachable by |prefix| from the trie root. Does nothing if such
   // subtree does not exist.
@@ -136,14 +126,6 @@ private:
       toDo(prefix, value);
   }
 
-  // Calls |toDo| for each value in |node|.
-  template <typename ToDo>
-  void ForEachValueInNode(Node const & node, ToDo && toDo) const
-  {
-    for (auto const & value : node.m_values)
-      toDo(value);
-  }
-
   // Calls |toDo| for each key-value pair in subtree where |node| is a
   // root of the subtree. |prefix| is a path from the trie root to the
   // |node|.
diff --git a/base/stl_helpers.hpp b/base/stl_helpers.hpp
index 2130dd03d7..5ee22b6897 100644
--- a/base/stl_helpers.hpp
+++ b/base/stl_helpers.hpp
@@ -2,6 +2,7 @@
 
 #include <algorithm>
 #include <functional>
+#include <type_traits>
 #include <utility>
 #include <vector>
 
@@ -137,4 +138,29 @@ typename std::underlying_type<T>::type Key(T value)
 {
   return static_cast<typename std::underlying_type<T>::type>(value);
 }
+
+// Use this if you want to make a functor whose first
+// argument is ignored and the rest are forwarded to |fn|.
+template <typename Fn>
+class IgnoreFirstArgument
+{
+public:
+  template <typename Gn>
+  IgnoreFirstArgument(Gn && gn) : m_fn(std::forward<Gn>(gn)) {}
+
+  template <typename Arg, typename... Args>
+  typename std::result_of<Fn(Args &&...)>::type operator()(Arg && arg, Args &&... args)
+  {
+    return m_fn(std::forward<Args>(args)...);
+  }
+
+private:
+  Fn m_fn;
+};
+
+template <typename Fn>
+IgnoreFirstArgument<Fn> MakeIgnoreFirstArgument(Fn && fn)
+{
+  return IgnoreFirstArgument<Fn>(std::forward<Fn>(fn));
+}
 }  // namespace my