遵循这个问题：Boost序列化子类我正在尝试支持使用 boost 序列化生成的存档的前向兼容性，但我在使用较旧的代码读取较新的存档时遇到问题：
class A {
public:
A() {}
virtual ~A() = default;
private:
friend class boost::serialization::access;
template <class Archive> void serialize(Archive &ar, const unsigned int version) {
ar &mAttributeFromA;
}
std::string mAttributeFromA = "mAttributeFromA";
};
BOOST_CLASS_VERSION(A, 0)
class B : public A {
public:
B() {}
private:
friend class boost::serialization::access;
template <class Archive> void serialize(Archive &ar, const unsigned int version)
{
ar &boost::serialization::base_object<A>(*this);
ar &mAttributeFromB;
if (version == 1)
ar &mNewAttribute;
}
std::string mAttributeFromB = "mAttributeFromB";
std::string mNewAttribute = "mNewAttribute";
};
BOOST_CLASS_VERSION(B, 1)
class Manager {
public:
boost::ptr_vector<A> mListOfA; // can store A or B
private:
friend class boost::serialization::access;
template <class Archive> void serialize(Archive &ar, const unsigned int /*version*/) { ar &mListOfA; }
};
BOOST_CLASS_VERSION(Manager, 0)
int main() {
Manager mgr;
mgr.mListOfA.push_back(new B);
mgr.mListOfA.push_back(new B);
std::ofstream ofs("myFile.txt");
{
boost::archive::text_oarchive oa(ofs);
oa << mgr;
}
try {
Manager mgr2;
std::ifstream ifs("myFile.txt");
boost::archive::text_iarchive ia(ifs);
ia >> mgr2;
mgr2.mListOfA.at(0);
} catch(boost::archive::archive_exception e)
{
e.what();
}
}
BOOST_CLASS_EXPORT(A)
BOOST_CLASS_EXPORT(B)
这将生成以下存档：
22 serialization::archive 13 0 0 0 0 2 3 1 B 1 1
0 1 0
1 15 mAttributeFromA 15 mAttributeFromB 13 mNewAttribute 3
2
3 15 mAttributeFromA 15 mAttributeFromB 13 mNewAttribute
如果我尝试使用相同的代码重新加载存档，一切都会完美运行。
但是，如果我尝试使用旧版本的代码加载存档：（类版本为 0 并且 mNewAttribute 消失了）
class B : public A {
public:
B() {}
private:
friend class boost::serialization::access;
template <class Archive> void serialize(Archive &ar, const unsigned int version)
{
ar &boost::serialization::base_object<A>(*this);
ar &mAttributeFromB;
}
std::string mAttributeFromB = "mAttributeFromB";
};
BOOST_CLASS_VERSION(B, 0)
反序列化给我带来了“输入流错误"
On Coliru
如何使用旧代码反序列化新存档？
- 编辑 -
奇怪的是，如果我添加AandB 对象内部的管理器正在工作。但是只有 A 或只有 B 就会失败......
