将数据从回调闭包传递给 Rust 中的 mpsc 生产者

Question

我有以下代码。我创建了一个 mpsc 通道，目标是将发送者传递给闭包，该闭包将注册为带有库的回调，然后将来自回调的数据发送到通道以供其他地方使用。

use std::sync::mpsc::channel;
use std::sync::mpsc::Sender;
use std::thread;

fn init(sender: Sender<&[u8]>) {
    let handle_event = |x:i32, data:&[u8]| {
        sender.send(data).unwrap();
        };
    //handle will be registered as callback with some library
    //and used later in this thread
    sender.send("Callback registered".as_bytes()).unwrap();
}

fn main() {
    let (producer, bottle) = channel();
    let child = thread::spawn(move ||init(producer));
    for message in bottle {
        //process data
    }
    let res = child.join();
    
}

但我在编译时收到以下错误：

error[E0312]: lifetime of reference outlives lifetime of borrowed content...
 --> src/main.rs:7:21
  |
7 |         sender.send(data).unwrap();
  |                     ^^^^
  |
note: ...the reference is valid for the anonymous lifetime defined on the function body at 5:24...
 --> src/main.rs:5:24
  |
5 | fn init(sender: Sender<&[u8]>) {
  |                        ^^^^^
note: ...but the borrowed content is only valid for the anonymous lifetime #1 defined on the body at 6:24
 --> src/main.rs:6:24
  |
6 |       let handle_event = |x:i32, data:&[u8]| {
  |  ________________________^
7 | |         sender.send(data).unwrap();
8 | |         };
  | |_________^

我该如何解决这个问题？我注册回调的那一行也会抛出这个错误。

explicit lifetime required in the type of `sender`
   |
64 |         .sample_cb(handle_event)
   |          ^^^^^^^^^ lifetime `'static` required

回调应该是这个特征

pub trait SampleCb: FnMut(i32, &[u8]) + 'static {}

我不确定第二个错误是否是由于第一个错误引起的，因为第一个错误无论是否注册为回调都会发生，如here

Answer 1

要修复您的第一个错误，只需在 Sender<&[u8]> 上命名生命周期，然后将该生命周期添加到 handle_event 的参数中：

// name the lifetime 'a
fn init<'a>(sender: Sender<&'a [u8]>) {
    // take in &'a [u8] instead of &[u8]
    let handle_event = |x: i32, data: &'a [u8]| {
        sender.send(data).unwrap();
    };
    // ...
}

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