Rust 闭包错误 -> ...由当前函数拥有 |捕获移动值 :

Question

这段代码:

//let seen_cell = std::cell::RefCell::new(window_0);
window_0.connect_delete_event(|_, _| {

    //window_0.destroy();
    window.hide();
    Inhibit(true)  
    });

button_0.connect_clicked(|_|{  
    window.show_all(); 
    }  
);

产生错误:

error[E0373]: closure may outlive the current function, but it borrows `window`, which is owned by the current function
   --> src/main.rs:192:36
    |
192 |     window_0.connect_delete_event( |_, _| {
    |                                    ^^^^^^ may outlive borrowed value `window`
...
195 |         window.hide();
    |         ------ `window` is borrowed here
    |
help: to force the closure to take ownership of `window` (and any other referenced variables), use the `move` keyword, as shown:
    |     window_0.connect_delete_event( move |_, _| {

error[E0373]: closure may outlive the current function, but it borrows `window`, which is owned by the current function
   --> src/main.rs:199:30
    |
199 |     button_0.connect_clicked(|_|{
    |                              ^^^ may outlive borrowed value `window`
200 |         window.show_all();
    |         ------ `window` is borrowed here
    |
help: to force the closure to take ownership of `window` (and any other referenced variables), use the `move` keyword, as shown:
    |     button_0.connect_clicked(move |_|{

如果我尝试这样做:

//let seen_cell = std::cell::RefCell::new(window_0);
window_0.connect_delete_event(move |_, _| {

    //window_0.destroy();
    window.hide();
    Inhibit(true)  
    });

button_0.connect_clicked(|_|{  
    window.show_all(); 
    }  
);

我得到错误:

error[E0373]: closure may outlive the current function, but it borrows `window`, which is owned by the current function
   --> src/main.rs:199:30
    |
199 |     button_0.connect_clicked(|_|{
    |                              ^^^ may outlive borrowed value `window`
200 |         window.show_all();
    |         ------ `window` is borrowed here
    |
help: to force the closure to take ownership of `window` (and any other referenced variables), use the `move` keyword, as shown:
    |     button_0.connect_clicked(move |_|{

error[E0382]: capture of moved value: `window`
   --> src/main.rs:199:30
    |
192 |     window_0.connect_delete_event(move |_, _| {
    |                                   ----------- value moved (into closure) here
...
199 |     button_0.connect_clicked(|_|{
    |                              ^^^ value captured here after move
    |
    = note: move occurs because `window` has type `gtk::Window`, which does not implement the `Copy` trait

如果我尝试这样做:

//let seen_cell = std::cell::RefCell::new(window_0);
window_0.connect_delete_event(move |_, _| {

    //window_0.destroy();
    window.hide();
    Inhibit(true)  
    });

button_0.connect_clicked(move|_|{  
    window.show_all(); 
    }  
);

我得到错误:

error[E0382]: capture of moved value: `window`
   --> src/main.rs:200:9
    |
192 |     window_0.connect_delete_event(move |_, _| {
    |                                   ----------- value moved (into closure) here
...
200 |         window.show_all();
    |         ^^^^^^ value captured here after move
    |
    = note: move occurs because `window` has type `gtk::Window`, which does not implement the `Copy` trait

我看过类似的问题，但我没能解决这个问题。我怎样才能以最好的方式解决这个问题，也许是使用 Arc 或类似的方法？

Answer 1

我已经使用从 gtk-rs 的一些示例项目中提取的宏解决了上述问题

macro_rules! clone {
        (@param _) => ( _ );
        (@param $x:ident) => ( $x );
        ($($n:ident),+ => move || $body:expr) => (
            {
                $( let $n = $n.clone(); )+
                move || $body
            }
        );
        ($($n:ident),+ => move |$($p:tt),+| $body:expr) => (
            {
                $( let $n = $n.clone(); )+
                move |$(clone!(@param $p),)+| $body
            }
        );
    }

---

以我所描述的案例为例:

window_0.connect_delete_event(clone!(window => move |_, _| {

//window_0.destroy();
window.hide();
Inhibit(true)  
}));

button_0.connect_clicked(clone!(window => move |_|{  
    window.show_all(); 

}));

这是相关部分 window_0.connect_delete_event(clone!(window => move。在我的例子中它也适用于 button_0.connect_clicked 因为 window 后面在类似的地方用到