Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 233 insertions, 0 deletions

diff --git a/third_party/rust/tokio/src/time/clock.rs b/third_party/rust/tokio/src/time/clock.rs
new file mode 100644
index 0000000000..41be9bac48
--- /dev/null
+++ b/third_party/rust/tokio/src/time/clock.rs
@@ -0,0 +1,233 @@
+#![cfg_attr(not(feature = "rt"), allow(dead_code))]
+
+//! Source of time abstraction.
+//!
+//! By default, `std::time::Instant::now()` is used. However, when the
+//! `test-util` feature flag is enabled, the values returned for `now()` are
+//! configurable.
+
+cfg_not_test_util! {
+    use crate::time::{Instant};
+
+    #[derive(Debug, Clone)]
+    pub(crate) struct Clock {}
+
+    pub(crate) fn now() -> Instant {
+        Instant::from_std(std::time::Instant::now())
+    }
+
+    impl Clock {
+        pub(crate) fn new(_enable_pausing: bool, _start_paused: bool) -> Clock {
+            Clock {}
+        }
+
+        pub(crate) fn now(&self) -> Instant {
+            now()
+        }
+    }
+}
+
+cfg_test_util! {
+    use crate::time::{Duration, Instant};
+    use crate::loom::sync::{Arc, Mutex};
+
+    cfg_rt! {
+        fn clock() -> Option<Clock> {
+            crate::runtime::context::clock()
+        }
+    }
+
+    cfg_not_rt! {
+        fn clock() -> Option<Clock> {
+            None
+        }
+    }
+
+    /// A handle to a source of time.
+    #[derive(Debug, Clone)]
+    pub(crate) struct Clock {
+        inner: Arc<Mutex<Inner>>,
+    }
+
+    #[derive(Debug)]
+    struct Inner {
+        /// True if the ability to pause time is enabled.
+        enable_pausing: bool,
+
+        /// Instant to use as the clock's base instant.
+        base: std::time::Instant,
+
+        /// Instant at which the clock was last unfrozen.
+        unfrozen: Option<std::time::Instant>,
+    }
+
+    /// Pauses time.
+    ///
+    /// The current value of `Instant::now()` is saved and all subsequent calls
+    /// to `Instant::now()` will return the saved value. The saved value can be
+    /// changed by [`advance`] or by the time auto-advancing once the runtime
+    /// has no work to do. This only affects the `Instant` type in Tokio, and
+    /// the `Instant` in std continues to work as normal.
+    ///
+    /// Pausing time requires the `current_thread` Tokio runtime. This is the
+    /// default runtime used by `#[tokio::test]`. The runtime can be initialized
+    /// with time in a paused state using the `Builder::start_paused` method.
+    ///
+    /// For cases where time is immediately paused, it is better to pause
+    /// the time using the `main` or `test` macro:
+    /// ```
+    /// #[tokio::main(flavor = "current_thread", start_paused = true)]
+    /// async fn main() {
+    ///    println!("Hello world");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// Panics if time is already frozen or if called from outside of a
+    /// `current_thread` Tokio runtime.
+    ///
+    /// # Auto-advance
+    ///
+    /// If time is paused and the runtime has no work to do, the clock is
+    /// auto-advanced to the next pending timer. This means that [`Sleep`] or
+    /// other timer-backed primitives can cause the runtime to advance the
+    /// current time when awaited.
+    ///
+    /// [`Sleep`]: crate::time::Sleep
+    /// [`advance`]: crate::time::advance
+    pub fn pause() {
+        let clock = clock().expect("time cannot be frozen from outside the Tokio runtime");
+        clock.pause();
+    }
+
+    /// Resumes time.
+    ///
+    /// Clears the saved `Instant::now()` value. Subsequent calls to
+    /// `Instant::now()` will return the value returned by the system call.
+    ///
+    /// # Panics
+    ///
+    /// Panics if time is not frozen or if called from outside of the Tokio
+    /// runtime.
+    pub fn resume() {
+        let clock = clock().expect("time cannot be frozen from outside the Tokio runtime");
+        let mut inner = clock.inner.lock();
+
+        if inner.unfrozen.is_some() {
+            panic!("time is not frozen");
+        }
+
+        inner.unfrozen = Some(std::time::Instant::now());
+    }
+
+    /// Advances time.
+    ///
+    /// Increments the saved `Instant::now()` value by `duration`. Subsequent
+    /// calls to `Instant::now()` will return the result of the increment.
+    ///
+    /// This function will make the current time jump forward by the given
+    /// duration in one jump. This means that all `sleep` calls with a deadline
+    /// before the new time will immediately complete "at the same time", and
+    /// the runtime is free to poll them in any order.  Additionally, this
+    /// method will not wait for the `sleep` calls it advanced past to complete.
+    /// If you want to do that, you should instead call [`sleep`] and rely on
+    /// the runtime's auto-advance feature.
+    ///
+    /// Note that calls to `sleep` are not guaranteed to complete the first time
+    /// they are polled after a call to `advance`. For example, this can happen
+    /// if the runtime has not yet touched the timer driver after the call to
+    /// `advance`. However if they don't, the runtime will poll the task again
+    /// shortly.
+    ///
+    /// # Panics
+    ///
+    /// Panics if time is not frozen or if called from outside of the Tokio
+    /// runtime.
+    ///
+    /// # Auto-advance
+    ///
+    /// If the time is paused and there is no work to do, the runtime advances
+    /// time to the next timer. See [`pause`](pause#auto-advance) for more
+    /// details.
+    ///
+    /// [`sleep`]: fn@crate::time::sleep
+    pub async fn advance(duration: Duration) {
+        let clock = clock().expect("time cannot be frozen from outside the Tokio runtime");
+        clock.advance(duration);
+
+        crate::task::yield_now().await;
+    }
+
+    /// Returns the current instant, factoring in frozen time.
+    pub(crate) fn now() -> Instant {
+        if let Some(clock) = clock() {
+            clock.now()
+        } else {
+            Instant::from_std(std::time::Instant::now())
+        }
+    }
+
+    impl Clock {
+        /// Returns a new `Clock` instance that uses the current execution context's
+        /// source of time.
+        pub(crate) fn new(enable_pausing: bool, start_paused: bool) -> Clock {
+            let now = std::time::Instant::now();
+
+            let clock = Clock {
+                inner: Arc::new(Mutex::new(Inner {
+                    enable_pausing,
+                    base: now,
+                    unfrozen: Some(now),
+                })),
+            };
+
+            if start_paused {
+                clock.pause();
+            }
+
+            clock
+        }
+
+        pub(crate) fn pause(&self) {
+            let mut inner = self.inner.lock();
+
+            if !inner.enable_pausing {
+                drop(inner); // avoid poisoning the lock
+                panic!("`time::pause()` requires the `current_thread` Tokio runtime. \
+                        This is the default Runtime used by `#[tokio::test].");
+            }
+
+            let elapsed = inner.unfrozen.as_ref().expect("time is already frozen").elapsed();
+            inner.base += elapsed;
+            inner.unfrozen = None;
+        }
+
+        pub(crate) fn is_paused(&self) -> bool {
+            let inner = self.inner.lock();
+            inner.unfrozen.is_none()
+        }
+
+        pub(crate) fn advance(&self, duration: Duration) {
+            let mut inner = self.inner.lock();
+
+            if inner.unfrozen.is_some() {
+                panic!("time is not frozen");
+            }
+
+            inner.base += duration;
+        }
+
+        pub(crate) fn now(&self) -> Instant {
+            let inner = self.inner.lock();
+
+            let mut ret = inner.base;
+
+            if let Some(unfrozen) = inner.unfrozen {
+                ret += unfrozen.elapsed();
+            }
+
+            Instant::from_std(ret)
+        }
+    }
+}