1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163
use futures_task::{LocalSpawn, Spawn}; #[cfg(feature = "compat")] use crate::compat::Compat; #[cfg(feature = "channel")] #[cfg(feature = "std")] use crate::future::{FutureExt, RemoteHandle}; #[cfg(feature = "alloc")] use alloc::boxed::Box; #[cfg(feature = "alloc")] use futures_core::future::Future; #[cfg(feature = "alloc")] use futures_task::{FutureObj, LocalFutureObj, SpawnError}; impl<Sp: ?Sized> SpawnExt for Sp where Sp: Spawn {} impl<Sp: ?Sized> LocalSpawnExt for Sp where Sp: LocalSpawn {} /// Extension trait for `Spawn`. pub trait SpawnExt: Spawn { /// Spawns a task that polls the given future with output `()` to /// completion. /// /// This method returns a [`Result`] that contains a [`SpawnError`] if /// spawning fails. /// /// You can use [`spawn_with_handle`](SpawnExt::spawn_with_handle) if /// you want to spawn a future with output other than `()` or if you want /// to be able to await its completion. /// /// Note this method will eventually be replaced with the upcoming /// `Spawn::spawn` method which will take a `dyn Future` as input. /// Technical limitations prevent `Spawn::spawn` from being implemented /// today. Feel free to use this method in the meantime. /// /// ``` /// use futures::executor::ThreadPool; /// use futures::task::SpawnExt; /// /// let executor = ThreadPool::new().unwrap(); /// /// let future = async { /* ... */ }; /// executor.spawn(future).unwrap(); /// ``` #[cfg(feature = "alloc")] fn spawn<Fut>(&self, future: Fut) -> Result<(), SpawnError> where Fut: Future<Output = ()> + Send + 'static, { self.spawn_obj(FutureObj::new(Box::new(future))) } /// Spawns a task that polls the given future to completion and returns a /// future that resolves to the spawned future's output. /// /// This method returns a [`Result`] that contains a [`RemoteHandle`](crate::future::RemoteHandle), or, if /// spawning fails, a [`SpawnError`]. [`RemoteHandle`](crate::future::RemoteHandle) is a future that /// resolves to the output of the spawned future. /// /// ``` /// use futures::executor::{block_on, ThreadPool}; /// use futures::future; /// use futures::task::SpawnExt; /// /// let executor = ThreadPool::new().unwrap(); /// /// let future = future::ready(1); /// let join_handle_fut = executor.spawn_with_handle(future).unwrap(); /// assert_eq!(block_on(join_handle_fut), 1); /// ``` #[cfg(feature = "channel")] #[cfg_attr(docsrs, doc(cfg(feature = "channel")))] #[cfg(feature = "std")] fn spawn_with_handle<Fut>(&self, future: Fut) -> Result<RemoteHandle<Fut::Output>, SpawnError> where Fut: Future + Send + 'static, Fut::Output: Send, { let (future, handle) = future.remote_handle(); self.spawn(future)?; Ok(handle) } /// Wraps a [`Spawn`] and makes it usable as a futures 0.1 `Executor`. /// Requires the `compat` feature to enable. #[cfg(feature = "compat")] #[cfg_attr(docsrs, doc(cfg(feature = "compat")))] fn compat(self) -> Compat<Self> where Self: Sized, { Compat::new(self) } } /// Extension trait for `LocalSpawn`. pub trait LocalSpawnExt: LocalSpawn { /// Spawns a task that polls the given future with output `()` to /// completion. /// /// This method returns a [`Result`] that contains a [`SpawnError`] if /// spawning fails. /// /// You can use [`spawn_with_handle`](SpawnExt::spawn_with_handle) if /// you want to spawn a future with output other than `()` or if you want /// to be able to await its completion. /// /// Note this method will eventually be replaced with the upcoming /// `Spawn::spawn` method which will take a `dyn Future` as input. /// Technical limitations prevent `Spawn::spawn` from being implemented /// today. Feel free to use this method in the meantime. /// /// ``` /// use futures::executor::LocalPool; /// use futures::task::LocalSpawnExt; /// /// let executor = LocalPool::new(); /// let spawner = executor.spawner(); /// /// let future = async { /* ... */ }; /// spawner.spawn_local(future).unwrap(); /// ``` #[cfg(feature = "alloc")] fn spawn_local<Fut>(&self, future: Fut) -> Result<(), SpawnError> where Fut: Future<Output = ()> + 'static, { self.spawn_local_obj(LocalFutureObj::new(Box::new(future))) } /// Spawns a task that polls the given future to completion and returns a /// future that resolves to the spawned future's output. /// /// This method returns a [`Result`] that contains a [`RemoteHandle`](crate::future::RemoteHandle), or, if /// spawning fails, a [`SpawnError`]. [`RemoteHandle`](crate::future::RemoteHandle) is a future that /// resolves to the output of the spawned future. /// /// ``` /// use futures::executor::LocalPool; /// use futures::task::LocalSpawnExt; /// /// let mut executor = LocalPool::new(); /// let spawner = executor.spawner(); /// /// let future = async { 1 }; /// let join_handle_fut = spawner.spawn_local_with_handle(future).unwrap(); /// assert_eq!(executor.run_until(join_handle_fut), 1); /// ``` #[cfg(feature = "channel")] #[cfg_attr(docsrs, doc(cfg(feature = "channel")))] #[cfg(feature = "std")] fn spawn_local_with_handle<Fut>( &self, future: Fut, ) -> Result<RemoteHandle<Fut::Output>, SpawnError> where Fut: Future + 'static, { let (future, handle) = future.remote_handle(); self.spawn_local(future)?; Ok(handle) } }