rust - PathBuf::from(＆some_other_pathbuf)会克隆some_other_pathbuf的数据吗？

Question

我正在编写一个custom_rename函数，该函数接收String和对PathBuf的不可变引用:

fn custom_rename(new_name: String, old_path: &PathBuf) {
    let mut new_path = PathBuf::from(&old_path);
    new_path.pop();
    new_path.push(new_name);
    std::fs::rename(old_path, new_path).expect("error");
}

PathBuf::from()函数会克隆 old_path的数据吗？根据 The Rust Programming Language，Rustaceans尝试避免克隆。

Answer 1

是的，PathBuf拥有数据。带有引用时，拥有数据的唯一方法是克隆数据。
我会这样写

use std::{fs, path::Path};

fn custom_rename(new_name: &str, old_path: &Path) {
    let mut new_path = old_path.to_owned();
    new_path.pop();
    new_path.push(new_name);
    fs::rename(old_path, new_path).expect("error");
}

也可以看看:

Is it more conventional to pass-by-value or pass-by-reference when the method needs ownership of the value?

Why is it discouraged to accept a reference to a String (&String), Vec (&Vec), or Box (&Box) as a function argument?