Fix and add tests for empty_base_optimization.

Builds/VisualStudio2013/beast.vcxproj

@@ -777,6 +777,12 @@
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
     </ClCompile>
+    <ClCompile Include="..\..\beast\utility\tests\empty_base_optimization.test.cpp">
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
+    </ClCompile>
     <ClCompile Include="..\..\beast\utility\Utility.cpp" />
     <ClCompile Include="..\..\modules\beast_asio\basics\PeerRole.cpp">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>

Builds/VisualStudio2013/beast.vcxproj.filters

@@ -321,6 +321,9 @@
     <Filter Include="beast\streams">
       <UniqueIdentifier>{899ea9a6-1969-4cde-b26d-8ad60acebfa4}</UniqueIdentifier>
     </Filter>
+    <Filter Include="beast\utility\tests">
+      <UniqueIdentifier>{3c58ba5e-1855-4865-8a9f-c0afd5014e74}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\modules\beast_core\beast_core.h">
@@ -1940,6 +1943,9 @@
     <ClCompile Include="..\..\beast\streams\streams.cpp">
       <Filter>beast\streams</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\beast\utility\tests\empty_base_optimization.test.cpp">
+      <Filter>beast\utility\tests</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <Text Include="..\..\TODO.txt">

beast/utility/Utility.cpp

@@ -32,3 +32,4 @@
 #include "impl/LeakChecked.cpp"
 #include "impl/StaticObject.cpp"
 #include "impl/PropertyStream.cpp"
+#include "tests/empty_base_optimization.test.cpp"

beast/utility/empty_base_optimization.h

@@ -24,20 +24,10 @@
 #include <type_traits>
 #include <utility>
 
-#ifndef BEAST_NO_EMPTY_BASE_OPTIMIZATION
-# if defined _MSC_VER
-#  define BEAST_NO_EMPTY_BASE_OPTIMIZATION 1
-# else
-#  define BEAST_NO_EMPTY_BASE_OPTIMIZATION 1
-# endif
-#endif
-
 namespace beast {
 
 namespace detail {
 
-#if ! BEAST_NO_EMPTY_BASE_OPTIMIZATION
-
 template <class T>
 struct empty_base_optimization_decide
     : std::integral_constant <bool,
@@ -49,16 +39,6 @@ struct empty_base_optimization_decide
 {
 };
 
-#else
-
-template <class T>
-struct empty_base_optimization_decide
-    : std::false_type
-{
-};
-
-#endif
-
 }
 
 //------------------------------------------------------------------------------
@@ -72,43 +52,15 @@ template <
 class empty_base_optimization : private T
 {
 public:
-    template <
-        class... Args,
-        class = typename std::enable_if <
-            std::is_constructible <T, Args...>::value>::type
-    >
-    explicit /*constexpr*/ empty_base_optimization (
-        Args&&... args)
-            /*noexcept (std::is_nothrow_constructible <T, Args...>::value);*/
-            : T (std::forward <Args> (args)...)
-    {
-    }
+    empty_base_optimization() = default;
 
-#if 1
-    empty_base_optimization (T const& t)
+    empty_base_optimization(T const& t)
         : T (t)
-    {
-    }
+    {}
 
-    empty_base_optimization (T&& t)
+    empty_base_optimization(T&& t)
         : T (std::move (t))
-    {
-    }
-
-    empty_base_optimization& operator= (
-        empty_base_optimization const& other)
-    {
-        *this = other;
-        return *this;
-    }
-
-    empty_base_optimization& operator= (
-        empty_base_optimization&& other)
-    {
-        *this = std::move (other);
-        return *this;
-    }
-#endif
+    {}
 
     T& member() noexcept
     {
@@ -130,17 +82,15 @@ template <
 class empty_base_optimization <T, UniqueID, false>
 {
 public:
-    template <
-        class... Args,
-        class = typename std::enable_if <
-            std::is_constructible <T, Args...>::value>::type
-    >
-    explicit /*constexpr*/ empty_base_optimization (
-        Args&&... args)
-            /*noexcept (std::is_nothrow_constructible <T, Args...>::value);*/
-            : m_t (std::forward <Args> (args)...)
-    {
-    }
+    empty_base_optimization() = default;
+
+    empty_base_optimization(T const& t)
+        : m_t (t)
+    {}
+
+    empty_base_optimization(T&& t)
+        : m_t (std::move (t))
+    {}
 
     T& member() noexcept
     {

beast/utility/tests/empty_base_optimization.test.cpp

@@ -0,0 +1,113 @@
+//-------------------- empty_base_optimization.test.cpp ------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2014 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#if BEAST_INCLUDE_BEASTCONFIG
+#include "../../../BeastConfig.h"
+#endif
+
+#include "../empty_base_optimization.h"
+
+#include "../../../modules/beast_core/beast_core.h" // for UnitTest
+
+namespace beast {
+
+class empty_base_optimization_Tests
+    : public UnitTest
+{
+public:
+    template <class T>
+    class test1
+        : private empty_base_optimization<T>
+    {
+        typedef empty_base_optimization<T> Base;
+        void* m_p;
+    public:
+        explicit test1 (T const& t)
+            : Base (t)
+        {}
+
+        T&       member()       {return Base::member();}
+        T const& member() const {return Base::member();}
+    };
+
+    template <class T>
+    class test2
+    {
+        void* m_p;
+        T m_t;
+    public:
+        explicit test2 (T const& t)
+            : m_t (t)
+        {}
+
+        T&       member()       {return m_t;}
+        T const& member() const {return m_t;}
+    };
+
+    struct Empty
+    {
+        operator bool() {return true;}
+    };
+
+    static
+    bool
+    test_one ()
+    {
+        test1<int> t1(1);
+        test2<int> t2(2);
+        static_assert(sizeof(t1) == sizeof(t2), "don't optimize for int");
+        if (t1.member() != 1)
+            return false;
+        if (t2.member() != 2)
+            return false;
+        return true;
+    }
+
+    static
+    bool
+    test_two ()
+    {
+        test1<Empty> t1((Empty()));
+        test2<Empty> t2((Empty()));
+        static_assert(sizeof(t1) < sizeof(t2), "do optimize for Empty");
+        if (t1.member() != true)
+            return false;
+        if (t2.member() != true)
+            return false;
+        return true;
+    }
+
+    void
+    runTest ()
+    {
+        beginTestCase ("empty_base_optimization");
+        expect (test_one());
+        expect (test_two());
+        pass ();
+    }
+
+    empty_base_optimization_Tests()
+        : UnitTest ("empty_base_optimization", "beast")
+    {
+    }
+};
+
+static empty_base_optimization_Tests empty_base_optimization_tests;
+
+}  // beast