03-Drop
Drop — Rust By Practice
内容来源 · Rust By Practice / Rust 语言实战
原文链接: https://practice-rust.beatai.org/smart-pointers/drop.html
Drop
Drop trait 允许我们在值离开作用域时自定义清理逻辑。Rust 会在变量离开作用域时自动调用 drop。
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| // 让代码工作
struct CustomSmartPointer {
data: String,
}
impl Drop for CustomSmartPointer {
fn drop(&mut self) {
println!("Dropping CustomSmartPointer with data `{}`!", self.data);
}
}
fn main() {
let c = CustomSmartPointer {
data: String::from("my stuff"),
};
println!("CustomSmartPointer created.");
println!("About to leave main.");
println!("Success!");
}
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| // 让代码工作
struct CustomSmartPointer {
data: String,
}
impl Drop for CustomSmartPointer {
fn drop(&mut self) {
println!("Dropping `{}`", self.data);
}
}
fn main() {
let c = CustomSmartPointer {
data: String::from("first"),
};
let d = CustomSmartPointer {
data: String::from("second"),
};
println!("Created two pointers.");
drop(c);
println!("Dropped first pointer early.");
println!("Success!");
}
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| // 填空
struct HasDrop(i32);
impl Drop for HasDrop {
fn drop(&mut self) {
println!("Dropped {}", self.0);
}
}
fn main() {
let a = HasDrop(1);
let b = HasDrop(2);
{
let c = HasDrop(3);
println!("inner scope");
}
println!("Success!");
}
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你可以在这里找到答案（在 solutions 路径下），但请只在需要时使用