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Jet Tang's questions

Martin Hope
Jet Tang
Asked: 2025-03-24 13:58:32 +0800 CST
  • 6

我正在创建一个具有两个参数的 API 函数，我希望第二个参数的类型取决于第一个参数的值，例如：

enum Component{
   Cpu,
   Disk
}

struct CpuState {
    pub frequency: u64
}

struct DiskState {
    pub speed: u64
}

type Handler<T> = Box<dyn Fn(T) -> Box<dyn Future<Output = String> + Send> + Send + Sync>;

// the type of parameter(`<T>`) in handler is depends on the component you chosen.
fn monitor(component: Component, handler: Handler){}

我尝试过的方法是使用特征，但不起作用：

trait StateEventHandler {
    type Component;
    type Handler;
}

impl StateEventHandler for CpuState {
    type Component = Component::Cpu; // error: expected type, found variant `Component::Cpu`
not a type
    type Handler = Handler<CpuState>;
}

impl StateEventHandler for DiskState {
    type Component = Component::DiskState; // error like above
    type Handler = Handler<DiskState>;
}

fn monitor<T: StateEventHandler>(component: T::Component, handler: T::Handler){}

怎么办呢？

rust