From fcf7e786b07fc2daa6a934abef3813319a9ebee8 Mon Sep 17 00:00:00 2001
From: Alex Fabijanic <alex@pocoproject.org>
Date: Mon, 27 Jun 2022 17:03:08 +0200
Subject: [PATCH] fix(Any): As of C++11, std::swap is noexcept. #2386

---
 Foundation/include/Poco/Any.h        | 29 +++++++++++++--
 Foundation/include/Poco/Config.h     |  2 +-
 Foundation/testsuite/src/AnyTest.cpp | 53 ++++++++++++++++++++++++++--
 3 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/Foundation/include/Poco/Any.h b/Foundation/include/Poco/Any.h
index 98eb5dbb67..ef325270b3 100644
--- a/Foundation/include/Poco/Any.h
+++ b/Foundation/include/Poco/Any.h
@@ -23,6 +23,9 @@
 #include <cstring>
 
 
+#define poco_any_assert(cond) do { if (!(cond)) std::abort(); } while (0)
+
+
 namespace Poco {
 
 class Any;
@@ -56,6 +59,9 @@ union Placeholder
 	/// (i.e. there will be no heap-allocation). The local buffer size is one byte
 	/// larger - [POCO_SMALL_OBJECT_SIZE + 1], additional byte value indicating
 	/// where the object was allocated (0 => heap, 1 => local).
+	///
+	/// Important: for SOO builds, only same-type (or trivial both-empty no-op)
+	/// swap operation is allowed.
 {
 public:
 	struct Size
@@ -82,8 +88,22 @@ union Placeholder
 
 	void swap(Placeholder& other) noexcept
 	{
-		poco_assert (isLocal() && other.isLocal());
-		std::swap(pHolder, other.pHolder);
+		bool empty = isEmpty();
+		bool otherEmpty = other.isEmpty();
+		bool local = isLocal();
+		bool otherLocal = other.isLocal();
+
+		if (empty && otherEmpty) return;
+		poco_any_assert (local == otherLocal);
+		if (!local) std::swap(pHolder, other.pHolder);
+		else
+		{
+			unsigned int sz = SizeV + 1;
+			unsigned char tmpHolder[sz] = {};
+			std::memcpy(tmpHolder, holder, sz);
+			std::memcpy(holder, other.holder, sz);
+			std::memcpy(other.holder, tmpHolder, sz);
+		}
 	}
 
 	void erase()
@@ -314,6 +334,11 @@ class Any
 		return empty() ? typeid(void) : content()->type();
 	}
 
+	bool local() const
+	{
+		return _valueHolder.isLocal();
+	}
+
 private:
 	class ValueHolder
 	{
diff --git a/Foundation/include/Poco/Config.h b/Foundation/include/Poco/Config.h
index 9cfa370808..33845ce823 100644
--- a/Foundation/include/Poco/Config.h
+++ b/Foundation/include/Poco/Config.h
@@ -79,7 +79,7 @@
 // while those smaller will be placement new-ed into an
 // internal stack-auto-allocated buffer.
 #if !defined(POCO_SMALL_OBJECT_SIZE)
-	#define POCO_SMALL_OBJECT_SIZE 32
+	#define POCO_SMALL_OBJECT_SIZE 64
 #endif
 
 
diff --git a/Foundation/testsuite/src/AnyTest.cpp b/Foundation/testsuite/src/AnyTest.cpp
index b8ed755143..0362bb4d40 100644
--- a/Foundation/testsuite/src/AnyTest.cpp
+++ b/Foundation/testsuite/src/AnyTest.cpp
@@ -186,6 +186,14 @@ void AnyTest::testAnySwap()
 {
 	std::string text = "test message";
 	Any original = text, swapped;
+#ifdef POCO_NO_SOO
+	assertFalse (original.local());
+#else
+	assertTrue (original.local());
+#endif
+	assertFalse (original.empty());
+	assertFalse (swapped.local());
+	assertTrue (swapped.empty());
 	std::string* originalPtr = AnyCast<std::string>(&original);
 	Any* swapResult = &original.swap(swapped);
 
@@ -194,10 +202,49 @@ void AnyTest::testAnySwap()
 	assertTrue (swapped.type() == typeid(std::string));
 	assertTrue (text == AnyCast<std::string>(swapped));
 	assertTrue (0 != originalPtr);
-#ifdef POCO_NO_SOO // pointers only match when heap-allocated
-	assertTrue (originalPtr == AnyCast<std::string>(&swapped));
-#endif
 	assertTrue (swapResult == &original);
+
+	struct BigObject
+	{
+		Poco::UInt64 one = 1;
+		Poco::UInt64 two = 2;
+		Poco::UInt64 three = 3;
+		Poco::UInt64 four = 4;
+		Poco::UInt64 five = 5;
+		Poco::UInt64 six = 6;
+		Poco::UInt64 seven = 7;
+		Poco::UInt64 eight = 8;
+		Poco::UInt64 nine = 9;
+
+		bool operator==(const BigObject& other)
+		{
+			return one == other.one &&
+				two == other.two &&
+				three == other.three &&
+				four == other.four &&
+				five == other.five &&
+				six == other.six &&
+				seven == other.seven &&
+				eight == other.eight &&
+				nine == other.nine;
+		}
+	};
+
+	BigObject bigObject;
+	Any bigOriginal = bigObject, swappedBig;
+	assertFalse (bigOriginal.local());
+	assertFalse (bigOriginal.empty());
+	assertFalse (swappedBig.local());
+	assertTrue (swappedBig.empty());
+	BigObject* bigPtr = AnyCast<BigObject>(&bigOriginal);
+	Any* swapBigResult = &bigOriginal.swap(swappedBig);
+
+	assertTrue (bigOriginal.empty());
+	assertTrue (!swappedBig.empty());
+	assertTrue (swappedBig.type() == typeid(BigObject));
+	assertTrue (bigObject == AnyCast<BigObject>(swappedBig));
+	assertTrue (0 != bigPtr);
+	assertTrue (swapBigResult == &bigOriginal);
 }