C++ 具有外部实例创建的ObjectPool
我尝试修改现有的对象池类,以便能够将实例创建者类作为参数传递给对象池。基本上,我希望能够将实际的对象构造排除在内存池之外,这样我就可以更自由地创建要池化的实例 以下是对象池定义:C++ 具有外部实例创建的ObjectPool,c++,templates,object,C++,Templates,Object,我尝试修改现有的对象池类,以便能够将实例创建者类作为参数传递给对象池。基本上,我希望能够将实际的对象构造排除在内存池之外,这样我就可以更自由地创建要池化的实例 以下是对象池定义: template < typename T, typename InstanceCreator = DefaultInstanceFactory<T> > class ObjectPool : private noncopyable { ... } 在上面的方法中,我标记了
template <
typename T,
typename InstanceCreator = DefaultInstanceFactory<T>
>
class ObjectPool : private noncopyable {
...
}
在上面的方法中,我标记了实际的问题行。我不知道如何用外部实例创建者替换placement newnew(obj)T()
行,以便重用该内存
为完整起见,将对象返回池的方法如下所示
ObjectPool<int> intPool((DefaultInstanceFactory<int>()));
template <typename T>
class DefaultInstanceFactory {
public:
T * operator ()() const {
return new T;
}
};
void returnObject(T * obj) {
// --- Get containing PooledItem pointer
PooledItem * item = reinterpret_cast<PooledItem *>(obj);
// --- Make sure object came from this pool
if (item->next != reinterpret_cast<PooledItem *>(this)) {
// throw Exception
}
// --- Destroy object now if we want to reconstruct it later
if (destroyOnRelease) {
item->cast()->~T();
item->initialized = false;
}
void returnObject(T*obj){
//---获取包含PooledItem指针的
PooledItem*项目=重新解释铸件(obj);
//---确保对象来自此池
如果(项目->下一步!=重新解释施法(此)){
//抛出异常
}
//---如果我们以后要重建对象,请立即销毁它
如果(destroyOnRelease){
物品->铸造()->~T();
item->initialized=false;
}
有谁能给我一些帮助,如何修改这些方法,使外部实例创建者能够正确地集成?到目前为止,我不知道是否需要更改returnObject方法中的某些内容,到目前为止,我认为没有
感谢您的帮助!听起来您需要更改InstanceFactory的签名以获取指针
template <typename T>
class DefaultInstanceFactory {
public:
void operator ()(T* out) const {
return new(out) T;
}
};
模板
类DefaultInstanceFactory{
公众:
void运算符()(T*out)常量{
返回新的(输出的)T;
}
};
T * borrowObject() {
PooledItem * item = getItem();
T * obj = item->cast();
if (! item->initialized) {
// old original line, call the defaut constructor of T
new (obj) T();
// how to integrate the external Instance Creator at this point?
//new (instCreator_ ()) T(1);
//instCreator_ ();
item->initialized = true;
}
if (obj == NULL) {
throw ObjectPoolException(
"Object is NULL!", __FILE__, __LINE__, __FUNCTION__);
}
return obj;
}
void returnObject(T * obj) {
// --- Get containing PooledItem pointer
PooledItem * item = reinterpret_cast<PooledItem *>(obj);
// --- Make sure object came from this pool
if (item->next != reinterpret_cast<PooledItem *>(this)) {
// throw Exception
}
// --- Destroy object now if we want to reconstruct it later
if (destroyOnRelease) {
item->cast()->~T();
item->initialized = false;
}
template <typename T>
class DefaultInstanceFactory {
public:
void operator ()(T* out) const {
return new(out) T;
}
};