Merging upstream version 1.72.1+dfsg1.

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

1 files changed, 143 insertions, 11 deletions

diff --git a/vendor/tokio/src/sync/semaphore.rs b/vendor/tokio/src/sync/semaphore.rs
index 4b697a9bf..e679d0e6b 100644
--- a/vendor/tokio/src/sync/semaphore.rs
+++ b/vendor/tokio/src/sync/semaphore.rs
@@ -1,5 +1,7 @@
 use super::batch_semaphore as ll; // low level implementation
 use super::{AcquireError, TryAcquireError};
+#[cfg(all(tokio_unstable, feature = "tracing"))]
+use crate::util::trace;
 use std::sync::Arc;
 
 /// Counting semaphore performing asynchronous permit acquisition.
@@ -71,12 +73,14 @@ use std::sync::Arc;
 /// }
 /// ```
 ///
-/// [`PollSemaphore`]: https://docs.rs/tokio-util/0.6/tokio_util/sync/struct.PollSemaphore.html
+/// [`PollSemaphore`]: https://docs.rs/tokio-util/latest/tokio_util/sync/struct.PollSemaphore.html
 /// [`Semaphore::acquire_owned`]: crate::sync::Semaphore::acquire_owned
 #[derive(Debug)]
 pub struct Semaphore {
     /// The low level semaphore
     ll_sem: ll::Semaphore,
+    #[cfg(all(tokio_unstable, feature = "tracing"))]
+    resource_span: tracing::Span,
 }
 
 /// A permit from the semaphore.
@@ -85,6 +89,7 @@ pub struct Semaphore {
 ///
 /// [`acquire`]: crate::sync::Semaphore::acquire()
 #[must_use]
+#[clippy::has_significant_drop]
 #[derive(Debug)]
 pub struct SemaphorePermit<'a> {
     sem: &'a Semaphore,
@@ -97,6 +102,7 @@ pub struct SemaphorePermit<'a> {
 ///
 /// [`acquire_owned`]: crate::sync::Semaphore::acquire_owned()
 #[must_use]
+#[clippy::has_significant_drop]
 #[derive(Debug)]
 pub struct OwnedSemaphorePermit {
     sem: Arc<Semaphore>,
@@ -119,10 +125,41 @@ fn bounds() {
 }
 
 impl Semaphore {
+    /// The maximum number of permits which a semaphore can hold. It is `usize::MAX >> 3`.
+    ///
+    /// Exceeding this limit typically results in a panic.
+    pub const MAX_PERMITS: usize = super::batch_semaphore::Semaphore::MAX_PERMITS;
+
     /// Creates a new semaphore with the initial number of permits.
+    ///
+    /// Panics if `permits` exceeds [`Semaphore::MAX_PERMITS`].
+    #[track_caller]
     pub fn new(permits: usize) -> Self {
+        #[cfg(all(tokio_unstable, feature = "tracing"))]
+        let resource_span = {
+            let location = std::panic::Location::caller();
+
+            tracing::trace_span!(
+                "runtime.resource",
+                concrete_type = "Semaphore",
+                kind = "Sync",
+                loc.file = location.file(),
+                loc.line = location.line(),
+                loc.col = location.column(),
+                inherits_child_attrs = true,
+            )
+        };
+
+        #[cfg(all(tokio_unstable, feature = "tracing"))]
+        let ll_sem = resource_span.in_scope(|| ll::Semaphore::new(permits));
+
+        #[cfg(any(not(tokio_unstable), not(feature = "tracing")))]
+        let ll_sem = ll::Semaphore::new(permits);
+
         Self {
-            ll_sem: ll::Semaphore::new(permits),
+            ll_sem,
+            #[cfg(all(tokio_unstable, feature = "tracing"))]
+            resource_span,
         }
     }
 
@@ -139,9 +176,16 @@ impl Semaphore {
     #[cfg(all(feature = "parking_lot", not(all(loom, test))))]
     #[cfg_attr(docsrs, doc(cfg(feature = "parking_lot")))]
     pub const fn const_new(permits: usize) -> Self {
-        Self {
+        #[cfg(all(tokio_unstable, feature = "tracing"))]
+        return Self {
             ll_sem: ll::Semaphore::const_new(permits),
-        }
+            resource_span: tracing::Span::none(),
+        };
+
+        #[cfg(any(not(tokio_unstable), not(feature = "tracing")))]
+        return Self {
+            ll_sem: ll::Semaphore::const_new(permits),
+        };
     }
 
     /// Returns the current number of available permits.
@@ -151,7 +195,7 @@ impl Semaphore {
 
     /// Adds `n` new permits to the semaphore.
     ///
-    /// The maximum number of permits is `usize::MAX >> 3`, and this function will panic if the limit is exceeded.
+    /// The maximum number of permits is [`Semaphore::MAX_PERMITS`], and this function will panic if the limit is exceeded.
     pub fn add_permits(&self, n: usize) {
         self.ll_sem.release(n);
     }
@@ -191,9 +235,20 @@ impl Semaphore {
     /// [`AcquireError`]: crate::sync::AcquireError
     /// [`SemaphorePermit`]: crate::sync::SemaphorePermit
     pub async fn acquire(&self) -> Result<SemaphorePermit<'_>, AcquireError> {
-        self.ll_sem.acquire(1).await?;
+        #[cfg(all(tokio_unstable, feature = "tracing"))]
+        let inner = trace::async_op(
+            || self.ll_sem.acquire(1),
+            self.resource_span.clone(),
+            "Semaphore::acquire",
+            "poll",
+            true,
+        );
+        #[cfg(not(all(tokio_unstable, feature = "tracing")))]
+        let inner = self.ll_sem.acquire(1);
+
+        inner.await?;
         Ok(SemaphorePermit {
-            sem: &self,
+            sem: self,
             permits: 1,
         })
     }
@@ -227,9 +282,21 @@ impl Semaphore {
     /// [`AcquireError`]: crate::sync::AcquireError
     /// [`SemaphorePermit`]: crate::sync::SemaphorePermit
     pub async fn acquire_many(&self, n: u32) -> Result<SemaphorePermit<'_>, AcquireError> {
+        #[cfg(all(tokio_unstable, feature = "tracing"))]
+        trace::async_op(
+            || self.ll_sem.acquire(n),
+            self.resource_span.clone(),
+            "Semaphore::acquire_many",
+            "poll",
+            true,
+        )
+        .await?;
+
+        #[cfg(not(all(tokio_unstable, feature = "tracing")))]
         self.ll_sem.acquire(n).await?;
+
         Ok(SemaphorePermit {
-            sem: &self,
+            sem: self,
             permits: n,
         })
     }
@@ -350,7 +417,18 @@ impl Semaphore {
     /// [`AcquireError`]: crate::sync::AcquireError
     /// [`OwnedSemaphorePermit`]: crate::sync::OwnedSemaphorePermit
     pub async fn acquire_owned(self: Arc<Self>) -> Result<OwnedSemaphorePermit, AcquireError> {
-        self.ll_sem.acquire(1).await?;
+        #[cfg(all(tokio_unstable, feature = "tracing"))]
+        let inner = trace::async_op(
+            || self.ll_sem.acquire(1),
+            self.resource_span.clone(),
+            "Semaphore::acquire_owned",
+            "poll",
+            true,
+        );
+        #[cfg(not(all(tokio_unstable, feature = "tracing")))]
+        let inner = self.ll_sem.acquire(1);
+
+        inner.await?;
         Ok(OwnedSemaphorePermit {
             sem: self,
             permits: 1,
@@ -403,7 +481,18 @@ impl Semaphore {
         self: Arc<Self>,
         n: u32,
     ) -> Result<OwnedSemaphorePermit, AcquireError> {
-        self.ll_sem.acquire(n).await?;
+        #[cfg(all(tokio_unstable, feature = "tracing"))]
+        let inner = trace::async_op(
+            || self.ll_sem.acquire(n),
+            self.resource_span.clone(),
+            "Semaphore::acquire_many_owned",
+            "poll",
+            true,
+        );
+        #[cfg(not(all(tokio_unstable, feature = "tracing")))]
+        let inner = self.ll_sem.acquire(n);
+
+        inner.await?;
         Ok(OwnedSemaphorePermit {
             sem: self,
             permits: n,
@@ -540,6 +629,25 @@ impl<'a> SemaphorePermit<'a> {
     pub fn forget(mut self) {
         self.permits = 0;
     }
+
+    /// Merge two [`SemaphorePermit`] instances together, consuming `other`
+    /// without releasing the permits it holds.
+    ///
+    /// Permits held by both `self` and `other` are released when `self` drops.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if permits from different [`Semaphore`] instances
+    /// are merged.
+    #[track_caller]
+    pub fn merge(&mut self, mut other: Self) {
+        assert!(
+            std::ptr::eq(self.sem, other.sem),
+            "merging permits from different semaphore instances"
+        );
+        self.permits += other.permits;
+        other.permits = 0;
+    }
 }
 
 impl OwnedSemaphorePermit {
@@ -549,9 +657,33 @@ impl OwnedSemaphorePermit {
     pub fn forget(mut self) {
         self.permits = 0;
     }
+
+    /// Merge two [`OwnedSemaphorePermit`] instances together, consuming `other`
+    /// without releasing the permits it holds.
+    ///
+    /// Permits held by both `self` and `other` are released when `self` drops.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if permits from different [`Semaphore`] instances
+    /// are merged.
+    #[track_caller]
+    pub fn merge(&mut self, mut other: Self) {
+        assert!(
+            Arc::ptr_eq(&self.sem, &other.sem),
+            "merging permits from different semaphore instances"
+        );
+        self.permits += other.permits;
+        other.permits = 0;
+    }
+
+    /// Returns the [`Semaphore`] from which this permit was acquired.
+    pub fn semaphore(&self) -> &Arc<Semaphore> {
+        &self.sem
+    }
 }
 
-impl<'a> Drop for SemaphorePermit<'_> {
+impl Drop for SemaphorePermit<'_> {
     fn drop(&mut self) {
         self.sem.add_permits(self.permits as usize);
     }