rust - 了解相关的生命周期

Question

我如何告诉编译器一个生命周期必须长于另一个生命周期？

use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, Debug)]
pub struct Tokens<'a> {
    buffer: String,
    list: Vec<Token<'a>>,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct Token<'a> {
    term: &'a str,
}

产量

error: lifetime may not live long enough
 --> src/pipeline/tokenizers/test.rs:6:5
  |
3 | #[derive(Serialize, Deserialize, Debug)]
  |                     ----------- lifetime `'de` defined here
4 | pub struct Tokens<'a> {
  |                   -- lifetime `'a` defined here
5 |     buffer: String,
6 |     list: Vec<Token<'a>>,
  |     ^^^^ requires that `'de` must outlive `'a`
  |
  = help: consider adding the following bound: `'de: 'a`

在上面的代码中，token.term: &str 将始终引用一片 tokens.buffer。我不确定如何指定这种关系。我也不确定如何添加请求的边界。

这会起作用吗？如果是这样，神奇的语法是什么？

Answer 1

您可以使用属性#[serde(borrow)]，它使生成的反序列化实现借用数据。

use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, Debug)]
pub struct Tokens<'a> {
    buffer: String,
    #[serde(borrow)]
    list: Vec<Token<'a>>,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct Token<'a> {
    term: &'a str,
}

参见:

• Borrowing Data in a Derived impl
• Serde field attributes (borrow)