refactor(Placeholder): more SOO consolidation and optimization

Foundation/include/Poco/Any.h

@@ -97,8 +97,8 @@ public:
 
 	bool isEmpty() const
 	{
-		char buf[POCO_SMALL_OBJECT_SIZE] = {};
+		char buf[SizeV] = {};
-		return 0 == std::memcmp(holder, buf, POCO_SMALL_OBJECT_SIZE);
+		return 0 == std::memcmp(holder, buf, SizeV);
 	}
 
 	bool isLocal() const
@@ -106,13 +106,9 @@ public:
 		return holder[SizeV] != 0;
 	}
 
-	void setLocal(bool local) const
+	template<typename T, typename V,
-	{
+		typename std::enable_if<TypeSizeLE<T, Placeholder::Size::value>::value>::type* = nullptr>
-		holder[SizeV] = local ? 1 : 0;
+	PlaceholderT* assign(const V& value)
-	}
-
-	template <typename T, typename V>
-	PlaceholderT* assignStack(const V& value)
 	{
 		erase();
 		new (reinterpret_cast<PlaceholderT*>(holder)) T(value);
@@ -120,8 +116,9 @@ public:
 		return reinterpret_cast<PlaceholderT*>(holder);
 	}
 
-	template <typename T, typename V>
+	template<typename T, typename V,
-	PlaceholderT* assignHeap(const V& value)
+		typename std::enable_if<TypeSizeGT<T, Placeholder::Size::value>::value>::type* = nullptr>
+	PlaceholderT* assign(const V& value)
 	{
 		erase();
 		pHolder = new T(value);
@@ -140,6 +137,11 @@ public:
 private:
 	typedef typename std::aligned_storage<SizeV+1>::type AlignerType;
 
+	void setLocal(bool local) const
+	{
+		holder[SizeV] = local ? 1 : 0;
+	}
+
 	void destruct(bool clear)
 	{
 		if (!isEmpty())
@@ -189,13 +191,7 @@ private:
 	}
 
 	template <typename T, typename V>
-	PlaceholderT* assignStack(const V& value)
+	PlaceholderT* assign(const V& value)
-	{
-		return assignHeap<T, V>(value);
-	}
-
-	template <typename T, typename V>
-	PlaceholderT* assignHeap(const V& value)
 	{
 		erase();
 		return pHolder = new T(value);
@@ -346,27 +342,13 @@ private:
 
 		virtual void clone(Placeholder<ValueHolder>* pPlaceholder) const
 		{
-			cloneSOO(pPlaceholder, _held);
+			pPlaceholder->assign<Holder<ValueType>, ValueType>(_held);
 		}
 
 		ValueType _held;
 
 	private:
 
-		template<typename VT,
-				 typename std::enable_if<TypeSizeLE<Holder<VT>, Placeholder<VT>::Size::value>::value>::type* = nullptr>
-		static void cloneSOO(Placeholder<ValueHolder>* pPlaceholder, VT& held)
-		{
-			pPlaceholder->assignStack<Holder<ValueType>, ValueType>(held);
-		}
-
-		template<typename VT,
-				 typename std::enable_if<TypeSizeGT<Holder<VT>, Placeholder<VT>::Size::value>::value>::type* = nullptr>
-		static void cloneSOO(Placeholder<ValueHolder>* pPlaceholder, VT& held)
-		{
-			pPlaceholder->assignHeap<Holder<ValueType>, ValueType>(held);
-		}
-
 		Holder & operator = (const Holder &);
 	};
 
@@ -375,18 +357,10 @@ private:
 		return _valueHolder.content();
 	}
 
-	template<typename ValueType,
+	template<typename ValueType>
-		 typename std::enable_if<TypeSizeLE<Holder<ValueType>, Placeholder<ValueType>::Size::value>::value>::type* = nullptr>
 	void construct(const ValueType& value)
 	{
-		_valueHolder.assignStack<Holder<ValueType>, ValueType>(value);
+		_valueHolder.assign<Holder<ValueType>, ValueType>(value);
-	}
-
-	template<typename ValueType,
-		 typename std::enable_if<TypeSizeGT<Holder<ValueType>, Placeholder<ValueType>::Size::value>::value>::type* = nullptr>
-	void construct(const ValueType& value)
-	{
-		_valueHolder.assignHeap<Holder<ValueType>, ValueType>(value);
 	}
 
 	void construct(const Any& other)

Foundation/include/Poco/Config.h

@@ -71,12 +71,7 @@
 // cases when value holder fits into POCO_SMALL_OBJECT_SIZE
 // (see below).
 //
-// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+// #define POCO_NO_SOO
-// !!! NOTE: Any/Dynamic::Var SOO will NOT work reliably   !!!
-// !!! without C++11 (std::aligned_storage in particular). !!!
-// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-//
-//#define POCO_NO_SOO
 
 
 // Small object size in bytes. When assigned to Any or Var,

Foundation/include/Poco/Dynamic/Var.h

@@ -225,6 +225,7 @@ public:
 	Var& operator = (const T& other)
 		/// Assignment operator for assigning POD to Var
 	{
+		clear();
 		construct(other);
 		return *this;
 	}
@@ -610,35 +611,20 @@ private:
 	{
 	}
 
-	template<typename ValueType,
-			 typename std::enable_if<TypeSizeLE<VarHolderImpl<ValueType>, Placeholder<ValueType>::Size::value>::value>::type* = nullptr>
-	void constructSOO(const ValueType& value)
-	{
-		_placeholder.assignStack<VarHolderImpl<ValueType>, ValueType>(value);
-	}
-
-	template<typename ValueType,
-			 typename std::enable_if<TypeSizeGT<VarHolderImpl<ValueType>, Placeholder<ValueType>::Size::value>::value>::type* = nullptr>
-	void constructSOO(const ValueType& value)
-	{
-		_placeholder.assignHeap<VarHolderImpl<ValueType>, ValueType>(value);
-	}
-
 	template<typename ValueType>
 	void construct(const ValueType& value)
 	{
-		constructSOO(value);
+		_placeholder.assign<VarHolderImpl<ValueType>, ValueType>(value);
 	}
 
 	void construct(const char* value)
 	{
 		std::string val(value);
-		constructSOO(val);
+		_placeholder.assign<VarHolderImpl<std::string>, std::string>(val);
 	}
 
 	void construct(const Var& other)
 	{
-		_placeholder.erase();
 		if (!other.isEmpty())
 			other.content()->clone(&_placeholder);
 	}

Foundation/include/Poco/Dynamic/VarHolder.h

@@ -306,7 +306,7 @@ protected:
 		/// pre-allocated buffer inside the holder).
 	{
 		poco_check_ptr (pVarHolder);
-		return makeSOOHolder(pVarHolder, val);
+		return pVarHolder->assign<VarHolderImpl<T>, T>(val);
 	}
 
 	template <typename F, typename T>
@@ -406,21 +406,6 @@ protected:
 	}
 
 private:
-	template<typename T,
-			 typename std::enable_if<TypeSizeLE<VarHolderImpl<T>, Placeholder<T>::Size::value>::value>::type* = nullptr>
-	VarHolder* makeSOOHolder(Placeholder<VarHolder>* pVarHolder, const T& val) const
-	{
-		poco_check_ptr (pVarHolder);
-		return pVarHolder->assignStack<VarHolderImpl<T>, T>(val);
-	}
-
-	template<typename T,
-			 typename std::enable_if<TypeSizeGT<VarHolderImpl<T>, Placeholder<T>::Size::value>::value>::type* = nullptr>
-	VarHolder* makeSOOHolder(Placeholder<VarHolder>* pVarHolder, const T& val) const
-	{
-		poco_check_ptr (pVarHolder);
-		return pVarHolder->assignHeap<VarHolderImpl<T>, T>(val);
-	}
 
 	template <typename F, typename T>
 	void checkUpperLimit(const F& from) const

Foundation/src/Var.cpp

@@ -52,11 +52,8 @@ Var::~Var()
 Var& Var::operator = (const Var& rhs)
 {
 	if (this == &rhs) return *this;
-	if (!rhs.isEmpty())
+	clear();
-		construct(rhs);
+	if (!rhs.isEmpty()) construct(rhs);
-	else
-		_placeholder.erase();
-
 	return *this;
 }
 

Foundation/testsuite/src/AnyTest.cpp

@@ -281,73 +281,43 @@ void AnyTest::testPlaceholder()
 	assertTrue(ph.isEmpty());
 	assertFalse(ph.isLocal());
 
-	char c = *ph.assignStack<char, char>(1);
+	char c = *ph.assign<char, char>(1);
 	assertTrue(1 == c);
 	assertFalse(ph.isEmpty());
 	assertTrue(ph.isLocal());
 
-	c = *ph.assignHeap<char, char>(2);
-	assertTrue(2 == c);
-	assertFalse(ph.isEmpty());
-	assertFalse(ph.isLocal());
-
 	ph.erase();
 	assertTrue(ph.isEmpty());
 	assertFalse(ph.isLocal());
 
-	if (sizeof(std::shared_ptr<int>) <= POCO_SMALL_OBJECT_SIZE)
-	{
 		Placeholder<std::shared_ptr<int>> sph;
 		assertTrue(sph.isEmpty());
 		assertFalse(sph.isLocal());
 
-		int i = **sph.assignStack<std::shared_ptr<int>, int*>(new int(1));
+		int i = **sph.assign<std::shared_ptr<int>, int*>(new int(1));
 		assertTrue(1 == i);
 		assertFalse(sph.isEmpty());
 		assertTrue(sph.isLocal());
 
-		i = **sph.assignHeap<std::shared_ptr<int>, int*>(new int(1));
-		assertTrue(1 == i);
-		assertFalse(sph.isEmpty());
-		assertFalse(sph.isLocal());
-	}
-
-	if (sizeof(Poco::SharedPtr<int>) <= POCO_SMALL_OBJECT_SIZE)
-	{
 		Placeholder<Poco::SharedPtr<int>> psph;
 		assertTrue(psph.isEmpty());
 		assertFalse(psph.isLocal());
 
-		int i = **psph.assignStack<Poco::SharedPtr<int>, int*>(new int(1));
+		i = **psph.assign<Poco::SharedPtr<int>, int*>(new int(2));
-		assertTrue(1 == i);
+		assertTrue(2 == i);
 		assertFalse(psph.isEmpty());
 		assertTrue(psph.isLocal());
 
-		i = **psph.assignHeap<Poco::SharedPtr<int>, int*>(new int(1));
-		assertTrue(1 == i);
-		assertFalse(psph.isEmpty());
-		assertFalse(psph.isLocal());
-	}
-
-	if (sizeof(std::vector<int>) <= POCO_SMALL_OBJECT_SIZE)
-	{
 		Placeholder<std::vector<int>> vph;
 		assertTrue(vph.isEmpty());
 		assertFalse(vph.isLocal());
 
 		std::vector<int> inv{1,2,3};
-		std::vector<int> outv = *vph.assignStack<std::vector<int>, std::vector<int>>(inv);
+		std::vector<int> outv = *vph.assign<std::vector<int>, std::vector<int>>(inv);
 		assertTrue(inv == outv);
 		assertFalse(vph.isEmpty());
 		assertTrue(vph.isLocal());
 
-		outv.clear();
-		outv = *vph.assignHeap<std::vector<int>, std::vector<int>>(inv);
-		assertTrue(inv == outv);
-		assertFalse(vph.isEmpty());
-		assertFalse(vph.isLocal());
-	}
-
 	// ...
 #endif
 }