C++ 使用C++；11?

下面是类似Qt的隐式共享/COW类的最小示例：

#include <QSharedData>
#include <QString>

class EmployeeData : public QSharedData
{
public:
    EmployeeData() : id(-1) { }
    EmployeeData(const EmployeeData &other)
        : QSharedData(other), id(other.id), name(other.name) { }
    ~EmployeeData() { }

    int id;
    QString name;
};

class Employee
{
public:
    Employee() { d = new EmployeeData; }
    Employee(int id, QString name) {
        d = new EmployeeData;
        setId(id);
        setName(name);
    }
    Employee(const Employee &other)
          : d (other.d)
    {
    }
    void setId(int id) { d->id = id; }
    void setName(QString name) { d->name = name; }

    int id() const { return d->id; }
    QString name() const { return d->name; }

private:
    QSharedDataPointer<EmployeeData> d;
};

---

谢谢。

“摆脱这种基本的getter/setter方法”，它与Qt的隐式共享无关，只是基本的API设计。如果您真的愿意，您可以将Qt的隐式共享机制包装在一个

ComplexStruct

实例周围，并在一个getter/setter对中公开整个结构。

struct A {
    ComplexStruct complexValue; // some struct which has lost of data
}

struct B {
    A value;
    int count;
}

int main() {
    B b;
    A a = b.value; // here I get deep copy of struct A with ComplexStruct, which is slow,
    // but with Qt-like implicitly sharing it will be fast and easy
}