AppFlowy/rust-lib/flowy-sys/src/handler/boxed.rs

use crate::error::Error;
use crate::payload::Payload;
use crate::request::FlowyRequest;
use crate::response::{FlowyResponse, Responder};
use crate::service::{Service, ServiceFactory, ServiceRequest, ServiceResponse};
use crate::util::ready::*;
use futures_core::ready;
use paste::paste;
use pin_project::pin_project;
use std::future::Future;
use std::marker::PhantomData;
use std::pin::Pin;
use std::task::{Context, Poll};

pub struct BoxServiceFactory<Cfg, Req, Res, Err, InitErr>(Inner<Cfg, Req, Res, Err, InitErr>);
impl<C, Req, Res, Err, InitErr> ServiceFactory<Req> for BoxServiceFactory<C, Req, Res, Err, InitErr>
where
    Req: 'static,
    Res: 'static,
    Err: 'static,
    InitErr: 'static,
{
    type Response = Res;
    type Error = Err;
    type Service = BoxService<Req, Res, Err>;
    type InitError = InitErr;
    type Config = C;

    type Future = BoxFuture<Result<Self::Service, InitErr>>;

    fn new_service(&self, cfg: C) -> Self::Future {
        self.0.new_service(cfg)
    }
}

pub type BoxFuture<T> = Pin<Box<dyn Future<Output = T>>>;
pub type BoxService<Req, Res, Err> =
    Box<dyn Service<Req, Response = Res, Error = Err, Future = BoxFuture<Result<Res, Err>>>>;

pub fn service<S, Req>(service: S) -> BoxService<Req, S::Response, S::Error>
where
    S: Service<Req> + 'static,
    Req: 'static,
    S::Future: 'static,
{
    Box::new(ServiceWrapper::new(service))
}

impl<S, Req> Service<Req> for Box<S>
where
    S: Service<Req> + ?Sized,
{
    type Response = S::Response;
    type Error = S::Error;
    type Future = S::Future;

    fn call(&self, request: Req) -> S::Future {
        (**self).call(request)
    }
}

struct ServiceWrapper<S> {
    inner: S,
}

impl<S> ServiceWrapper<S> {
    fn new(inner: S) -> Self {
        Self { inner }
    }
}

impl<S, Req, Res, Err> Service<Req> for ServiceWrapper<S>
where
    S: Service<Req, Response = Res, Error = Err>,
    S::Future: 'static,
{
    type Response = Res;
    type Error = Err;
    type Future = BoxFuture<Result<Res, Err>>;

    fn call(&self, req: Req) -> Self::Future {
        Box::pin(self.inner.call(req))
    }
}

struct FactoryWrapper<SF>(SF);

impl<SF, Req, Cfg, Res, Err, InitErr> ServiceFactory<Req> for FactoryWrapper<SF>
where
    Req: 'static,
    Res: 'static,
    Err: 'static,
    InitErr: 'static,
    SF: ServiceFactory<Req, Config = Cfg, Response = Res, Error = Err, InitError = InitErr>,
    SF::Future: 'static,
    SF::Service: 'static,
    <SF::Service as Service<Req>>::Future: 'static,
{
    type Response = Res;
    type Error = Err;
    // type Service: Service<Req, Response = Self::Response, Error = Self::Error>;
    type Service = BoxService<Req, Res, Err>;
    type InitError = InitErr;
    type Config = Cfg;
    type Future = BoxFuture<Result<Self::Service, Self::InitError>>;

    fn new_service(&self, cfg: Cfg) -> Self::Future {
        let f = self.0.new_service(cfg);
        Box::pin(async { f.await.map(|s| Box::new(ServiceWrapper::new(s)) as _) })
    }
}

pub fn factory<SF, Req>(
    factory: SF,
) -> BoxServiceFactory<SF::Config, Req, SF::Response, SF::Error, SF::InitError>
where
    SF: ServiceFactory<Req> + 'static,
    Req: 'static,
    SF::Response: 'static,
    SF::Service: 'static,
    SF::Future: 'static,
    SF::Error: 'static,
    SF::InitError: 'static,
{
    BoxServiceFactory(Box::new(FactoryWrapper(factory)))
}

type Inner<C, Req, Res, Err, InitErr> = Box<
    dyn ServiceFactory<
        Req,
        Config = C,
        Response = Res,
        Error = Err,
        InitError = InitErr,
        Service = BoxService<Req, Res, Err>,
        Future = BoxFuture<Result<BoxService<Req, Res, Err>, InitErr>>,
    >,
>;