vendor/tokio/src/runtime/current_thread/mod.rs

//! A runtime implementation that runs everything on the current thread.
//!
//! [`current_thread::Runtime`][rt] is similar to the primary
//! [`Runtime`][concurrent-rt] except that it runs all components on the current
//! thread instead of using a thread pool. This means that it is able to spawn
//! futures that do not implement `Send`.
//!
//! Same as the default [`Runtime`][concurrent-rt], the
//! [`current_thread::Runtime`][rt] includes:
//!
//! * A [reactor] to drive I/O resources.
//! * An [executor] to execute tasks that use these I/O resources.
//! * A [timer] for scheduling work to run after a set period of time.
//!
//! Note that [`current_thread::Runtime`][rt] does not implement `Send` itself
//! and cannot be safely moved to other threads.
//!
//! # Spawning from other threads
//!
//! While [`current_thread::Runtime`][rt] does not implement `Send` and cannot
//! safely be moved to other threads, it provides a `Handle` that can be sent
//! to other threads and allows to spawn new tasks from there.
//!
//! For example:
//!
//! ```
//! # extern crate tokio;
//! # extern crate futures;
//! use tokio::runtime::current_thread::Runtime;
//! use tokio::prelude::*;
//! use std::thread;
//!
//! # fn main() {
//! let mut runtime = Runtime::new().unwrap();
//! let handle = runtime.handle();
//!
//! thread::spawn(move || {
//!     handle.spawn(future::ok(()));
//! }).join().unwrap();
//!
//! # /*
//! runtime.run().unwrap();
//! # */
//! # }
//! ```
//!
//! # Examples
//!
//! Creating a new `Runtime` and running a future `f` until its completion and
//! returning its result.
//!
//! ```
//! use tokio::runtime::current_thread::Runtime;
//! use tokio::prelude::*;
//!
//! let mut runtime = Runtime::new().unwrap();
//!
//! // Use the runtime...
//! // runtime.block_on(f); // where f is a future
//! ```
//!
//! [rt]: struct.Runtime.html
//! [concurrent-rt]: ../struct.Runtime.html
//! [chan]: https://docs.rs/futures/0.1/futures/sync/mpsc/fn.channel.html
//! [reactor]: ../../reactor/struct.Reactor.html
//! [executor]: https://tokio.rs/docs/getting-started/runtime-model/#executors
//! [timer]: ../../timer/index.html

mod builder;
mod runtime;

pub use self::builder::Builder;
pub use self::runtime::{Runtime, Handle};
pub use tokio_current_thread::spawn;
pub use tokio_current_thread::TaskExecutor;

use futures::Future;

/// Run the provided future to completion using a runtime running on the current thread.
///
/// This first creates a new [`Runtime`], and calls [`Runtime::block_on`] with the provided future,
/// which blocks the current thread until the provided future completes. It then calls
/// [`Runtime::run`] to wait for any other spawned futures to resolve.
pub fn block_on_all<F>(future: F) -> Result<F::Item, F::Error>
where
    F: Future,
{
    let mut r = Runtime::new().expect("failed to start runtime on current thread");
    let v = r.block_on(future)?;
    r.run().expect("failed to resolve remaining futures");
    Ok(v)
}

/// Start a current-thread runtime using the supplied future to bootstrap execution.
///
/// # Panics
///
/// This function panics if called from the context of an executor.
pub fn run<F>(future: F)
where
    F: Future<Item = (), Error = ()> + 'static,
{

    let mut r = Runtime::new().expect("failed to start runtime on current thread");
    r.spawn(future);
    r.run().expect("failed to resolve remaining futures");
}