Merge pull request #795 from Rustln/main

Perfect `async/.await` example
pull/801/head
Sunface 3 years ago committed by GitHub
commit dee1c9ed02
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@ -278,9 +278,30 @@ hello, world!
考虑一个载歌载舞的例子,如果不用`.await`,我们可能会有如下实现:
```rust
async fn learn_song() -> Song { /* ... */ }
async fn sing_song(song: Song) { /* ... */ }
async fn dance() { /* ... */ }
use futures::executor::block_on;
struct Song {
author: String,
name: String,
}
async fn learn_song() -> Song {
Song {
author: "曲婉婷".to_string(),
name: String::from("《我的歌声里》"),
}
}
async fn sing_song(song: Song) {
println!(
"给大家献上一首{}的{} ~ {}",
song.author, song.name, "你存在我深深的脑海里~ ~"
);
}
async fn dance() {
println!("唱到情深处,身体不由自主的动了起来~ ~");
}
fn main() {
let song = block_on(learn_song());
@ -292,7 +313,31 @@ fn main() {
当然,以上代码运行结果无疑是正确的,但。。。它的性能何在?需要通过连续三次阻塞去等待三个任务的完成,一次只能做一件事,实际上我们完全可以载歌载舞啊:
```rust
async fn sing_song(song: Song) { /* ... */ }
use futures::executor::block_on;
struct Song {
author: String,
name: String,
}
async fn learn_song() -> Song {
Song {
author: "曲婉婷".to_string(),
name: String::from("《我的歌声里》"),
}
}
async fn sing_song(song: Song) {
println!(
"给大家献上一首{}的{} ~ {}",
song.author, song.name, "你存在我深深的脑海里~ ~"
);
}
async fn dance() {
println!("唱到情深处,身体不由自主的动了起来~ ~");
}
async fn learn_and_sing() {
// 这里使用`.await`来等待学歌的完成,但是并不会阻塞当前线程,该线程在学歌的任务`.await`后,完全可以去执行跳舞的任务
let song = learn_song().await;

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