Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 134 insertions, 0 deletions

diff --git a/third_party/rust/tokio/src/task/spawn.rs b/third_party/rust/tokio/src/task/spawn.rs
new file mode 100644
index 0000000000..fa5ff13b01
--- /dev/null
+++ b/third_party/rust/tokio/src/task/spawn.rs
@@ -0,0 +1,134 @@
+use crate::runtime;
+use crate::task::JoinHandle;
+
+use std::future::Future;
+
+doc_rt_core! {
+    /// Spawns a new asynchronous task, returning a
+    /// [`JoinHandle`](super::JoinHandle) for it.
+    ///
+    /// Spawning a task enables the task to execute concurrently to other tasks. The
+    /// spawned task may execute on the current thread, or it may be sent to a
+    /// different thread to be executed. The specifics depend on the current
+    /// [`Runtime`](crate::runtime::Runtime) configuration.
+    ///
+    /// There is no guarantee that a spawned task will execute to completion.
+    /// When a runtime is shutdown, all outstanding tasks are dropped,
+    /// regardless of the lifecycle of that task.
+    ///
+    /// This function must be called from the context of a Tokio runtime. Tasks running on
+    /// the Tokio runtime are always inside its context, but you can also enter the context
+    /// using the [`Handle::enter`](crate::runtime::Handle::enter()) method.
+    ///
+    /// # Examples
+    ///
+    /// In this example, a server is started and `spawn` is used to start a new task
+    /// that processes each received connection.
+    ///
+    /// ```no_run
+    /// use tokio::net::{TcpListener, TcpStream};
+    ///
+    /// use std::io;
+    ///
+    /// async fn process(socket: TcpStream) {
+    ///     // ...
+    /// # drop(socket);
+    /// }
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> io::Result<()> {
+    ///     let mut listener = TcpListener::bind("127.0.0.1:8080").await?;
+    ///
+    ///     loop {
+    ///         let (socket, _) = listener.accept().await?;
+    ///
+    ///         tokio::spawn(async move {
+    ///             // Process each socket concurrently.
+    ///             process(socket).await
+    ///         });
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// Panics if called from **outside** of the Tokio runtime.
+    ///
+    /// # Using `!Send` values from a task
+    ///
+    /// The task supplied to `spawn` must implement `Send`. However, it is
+    /// possible to **use** `!Send` values from the task as long as they only
+    /// exist between calls to `.await`.
+    ///
+    /// For example, this will work:
+    ///
+    /// ```
+    /// use tokio::task;
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// fn use_rc(rc: Rc<()>) {
+    ///     // Do stuff w/ rc
+    /// # drop(rc);
+    /// }
+    ///
+    /// #[tokio::main]
+    /// async fn main() {
+    ///     tokio::spawn(async {
+    ///         // Force the `Rc` to stay in a scope with no `.await`
+    ///         {
+    ///             let rc = Rc::new(());
+    ///             use_rc(rc.clone());
+    ///         }
+    ///
+    ///         task::yield_now().await;
+    ///     }).await.unwrap();
+    /// }
+    /// ```
+    ///
+    /// This will **not** work:
+    ///
+    /// ```compile_fail
+    /// use tokio::task;
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// fn use_rc(rc: Rc<()>) {
+    ///     // Do stuff w/ rc
+    /// # drop(rc);
+    /// }
+    ///
+    /// #[tokio::main]
+    /// async fn main() {
+    ///     tokio::spawn(async {
+    ///         let rc = Rc::new(());
+    ///
+    ///         task::yield_now().await;
+    ///
+    ///         use_rc(rc.clone());
+    ///     }).await.unwrap();
+    /// }
+    /// ```
+    ///
+    /// Holding on to a `!Send` value across calls to `.await` will result in
+    /// an unfriendly compile error message similar to:
+    ///
+    /// ```text
+    /// `[... some type ...]` cannot be sent between threads safely
+    /// ```
+    ///
+    /// or:
+    ///
+    /// ```text
+    /// error[E0391]: cycle detected when processing `main`
+    /// ```
+    pub fn spawn<T>(task: T) -> JoinHandle<T::Output>
+    where
+        T: Future + Send + 'static,
+        T::Output: Send + 'static,
+    {
+        let spawn_handle = runtime::context::spawn_handle()
+        .expect("must be called from the context of Tokio runtime configured with either `basic_scheduler` or `threaded_scheduler`");
+        spawn_handle.spawn(task)
+    }
+}