视频地址

头条地址：https://www.ixigua.com/i6775861706447913485
Ｂ站地址：https://www.bilibili.com/video/av81202308/

源码地址

github地址：https://github.com/anonymousGiga/learn_rust

讲解内容

自定义智能指针MyBox：实现Deref trait
//+++++++错误代码+++++++++++++++++

struct MyBox<T>(T);
impl<T> MyBox<T> {
    fn new(x: T) -> MyBox<T> {
        MyBox(x)
    }
}

fn main() {
    let x = 5;
    let y = MyBox::new(x);
    assert_eq!(5, x);
    assert_eq!(5, *y);
}

//+++++++++正确代码++++++++++++++++

//实现Deref Trait
use std::ops::Deref;
struct MyBox<T>(T);
impl<T> MyBox<T> {
    fn new(x: T) -> MyBox<T> {
        MyBox(x)
    }
}

impl<T> Deref for MyBox<T> { //为MyBox实现Deref trait
    type Target = T;
    fn deref(&self) -> &T { //注意：此处返回值是引用，因为一般并不希望解引用获取MyBox<T>内部值的所有权
        &self.0
    }
}

fn main() {
    let x = 5;
    let y = MyBox::new(x);
    assert_eq!(5, x);
    assert_eq!(5, *y); //实现Deref trait后即可解引用，使用*y实际等价于 *(y.deref())
}