Add folly::Identity function object to Utility.h; replace AtomicHashArray's AHAIdenti...

[folly.git] / folly / AtomicHashArray.h

diff --git a/folly/AtomicHashArray.h b/folly/AtomicHashArray.h
index 96a647d1a3da6bcf0e0f907273a20da1c09f7a24..e590dad5cdb38b2a882043bc87d0d1b84bfa0672 100644 (file)
--- a/folly/AtomicHashArray.h
+++ b/folly/AtomicHashArray.h
@@ -39,6 +39,7 @@
 
 #include <folly/Hash.h>
 #include <folly/ThreadCachedInt.h>
+#include <folly/Utility.h>
 
 namespace folly {
 
@@ -66,16 +67,6 @@ struct AtomicHashArrayQuadraticProbeFcn
 
 // Enables specializing checkLegalKey without specializing its class.
 namespace detail {
-// Local copy of folly::gen::Identity, to avoid heavy dependencies.
-class AHAIdentity {
- public:
-  template<class Value>
-  auto operator()(Value&& value) const ->
-    decltype(std::forward<Value>(value)) {
-    return std::forward<Value>(value);
-  }
-};
-
 template <typename NotKeyT, typename KeyT>
 inline void checkLegalKeyIfKeyTImpl(NotKeyT /* ignored */,
                                     KeyT /* emptyKey */,
@@ -91,20 +82,24 @@ inline void checkLegalKeyIfKeyTImpl(KeyT key_in, KeyT emptyKey,
 }
 }  // namespace detail
 
-template <class KeyT, class ValueT,
-          class HashFcn = std::hash<KeyT>,
-          class EqualFcn = std::equal_to<KeyT>,
-          class Allocator = std::allocator<char>,
-          class ProbeFcn = AtomicHashArrayLinearProbeFcn,
-          class KeyConvertFcn = detail::AHAIdentity>
+template <
+    class KeyT,
+    class ValueT,
+    class HashFcn = std::hash<KeyT>,
+    class EqualFcn = std::equal_to<KeyT>,
+    class Allocator = std::allocator<char>,
+    class ProbeFcn = AtomicHashArrayLinearProbeFcn,
+    class KeyConvertFcn = Identity>
 class AtomicHashMap;
 
-template <class KeyT, class ValueT,
-          class HashFcn = std::hash<KeyT>,
-          class EqualFcn = std::equal_to<KeyT>,
-          class Allocator = std::allocator<char>,
-          class ProbeFcn = AtomicHashArrayLinearProbeFcn,
-          class KeyConvertFcn = detail::AHAIdentity>
+template <
+    class KeyT,
+    class ValueT,
+    class HashFcn = std::hash<KeyT>,
+    class EqualFcn = std::equal_to<KeyT>,
+    class Allocator = std::allocator<char>,
+    class ProbeFcn = AtomicHashArrayLinearProbeFcn,
+    class KeyConvertFcn = Identity>
 class AtomicHashArray : boost::noncopyable {
   static_assert((std::is_convertible<KeyT,int32_t>::value ||
                  std::is_convertible<KeyT,int64_t>::value ||
@@ -348,13 +343,12 @@ friend class AtomicHashMap<KeyT,
     SimpleRetT() = default;
   };
 
-
-
-  template <typename LookupKeyT = key_type,
-            typename LookupHashFcn = hasher,
-            typename LookupEqualFcn = key_equal,
-            typename LookupKeyToKeyFcn = detail::AHAIdentity,
-            typename... ArgTs>
+  template <
+      typename LookupKeyT = key_type,
+      typename LookupHashFcn = hasher,
+      typename LookupEqualFcn = key_equal,
+      typename LookupKeyToKeyFcn = Identity,
+      typename... ArgTs>
   SimpleRetT insertInternal(LookupKeyT key, ArgTs&&... vCtorArgs);
 
   template <typename LookupKeyT = key_type,