From 070cd265e47a601b572a26f0cc2dd30473f700fc Mon Sep 17 00:00:00 2001
From: Taiki Endo <te316e89@gmail.com>
Date: Sun, 13 Mar 2022 01:39:59 +0900
Subject: [PATCH] Do not panic on very large timeout

---
 crossbeam-channel/src/channel.rs      | 5 +++--
 crossbeam-channel/src/flavors/at.rs   | 2 +-
 crossbeam-channel/src/flavors/tick.rs | 3 ++-
 crossbeam-channel/src/select.rs       | 4 ++--
 crossbeam-channel/src/utils.rs        | 8 ++++++++
 crossbeam-utils/src/sync/parker.rs    | 7 ++++++-
 6 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/crossbeam-channel/src/channel.rs b/crossbeam-channel/src/channel.rs
index 8988235db..e16f226b1 100644
--- a/crossbeam-channel/src/channel.rs
+++ b/crossbeam-channel/src/channel.rs
@@ -14,6 +14,7 @@ use crate::err::{
 };
 use crate::flavors;
 use crate::select::{Operation, SelectHandle, Token};
+use crate::utils;
 
 /// Creates a channel of unbounded capacity.
 ///
@@ -471,7 +472,7 @@ impl<T> Sender<T> {
     /// );
     /// ```
     pub fn send_timeout(&self, msg: T, timeout: Duration) -> Result<(), SendTimeoutError<T>> {
-        self.send_deadline(msg, Instant::now() + timeout)
+        self.send_deadline(msg, utils::timeout_to_deadline(timeout))
     }
 
     /// Waits for a message to be sent into the channel, but only until a given deadline.
@@ -861,7 +862,7 @@ impl<T> Receiver<T> {
     /// );
     /// ```
     pub fn recv_timeout(&self, timeout: Duration) -> Result<T, RecvTimeoutError> {
-        self.recv_deadline(Instant::now() + timeout)
+        self.recv_deadline(utils::timeout_to_deadline(timeout))
     }
 
     /// Waits for a message to be received from the channel, but only before a given deadline.
diff --git a/crossbeam-channel/src/flavors/at.rs b/crossbeam-channel/src/flavors/at.rs
index 23a7ae734..ee49244c4 100644
--- a/crossbeam-channel/src/flavors/at.rs
+++ b/crossbeam-channel/src/flavors/at.rs
@@ -35,7 +35,7 @@ impl Channel {
     /// Creates a channel that delivers a message after a certain duration of time.
     #[inline]
     pub(crate) fn new_timeout(dur: Duration) -> Self {
-        Self::new_deadline(Instant::now() + dur)
+        Self::new_deadline(utils::timeout_to_deadline(dur))
     }
 
     /// Attempts to receive a message without blocking.
diff --git a/crossbeam-channel/src/flavors/tick.rs b/crossbeam-channel/src/flavors/tick.rs
index bd12929a9..147098c68 100644
--- a/crossbeam-channel/src/flavors/tick.rs
+++ b/crossbeam-channel/src/flavors/tick.rs
@@ -10,6 +10,7 @@ use crossbeam_utils::atomic::AtomicCell;
 use crate::context::Context;
 use crate::err::{RecvTimeoutError, TryRecvError};
 use crate::select::{Operation, SelectHandle, Token};
+use crate::utils;
 
 /// Result of a receive operation.
 pub(crate) type TickToken = Option<Instant>;
@@ -28,7 +29,7 @@ impl Channel {
     #[inline]
     pub(crate) fn new(dur: Duration) -> Self {
         Channel {
-            delivery_time: AtomicCell::new(Instant::now() + dur),
+            delivery_time: AtomicCell::new(utils::timeout_to_deadline(dur)),
             duration: dur,
         }
     }
diff --git a/crossbeam-channel/src/select.rs b/crossbeam-channel/src/select.rs
index ea70a9eb1..b2f3e01b3 100644
--- a/crossbeam-channel/src/select.rs
+++ b/crossbeam-channel/src/select.rs
@@ -487,7 +487,7 @@ pub fn select_timeout<'a>(
     handles: &mut [(&'a dyn SelectHandle, usize, *const u8)],
     timeout: Duration,
 ) -> Result<SelectedOperation<'a>, SelectTimeoutError> {
-    select_deadline(handles, Instant::now() + timeout)
+    select_deadline(handles, utils::timeout_to_deadline(timeout))
 }
 
 /// Blocks until a given deadline, or until one of the operations becomes ready and selects it.
@@ -1043,7 +1043,7 @@ impl<'a> Select<'a> {
     /// }
     /// ```
     pub fn ready_timeout(&mut self, timeout: Duration) -> Result<usize, ReadyTimeoutError> {
-        self.ready_deadline(Instant::now() + timeout)
+        self.ready_deadline(utils::timeout_to_deadline(timeout))
     }
 
     /// Blocks until a given deadline, or until one of the operations becomes ready.
diff --git a/crossbeam-channel/src/utils.rs b/crossbeam-channel/src/utils.rs
index 557b6a0d7..cebe59da1 100644
--- a/crossbeam-channel/src/utils.rs
+++ b/crossbeam-channel/src/utils.rs
@@ -61,6 +61,14 @@ pub(crate) fn sleep_until(deadline: Option<Instant>) {
     }
 }
 
+// https://github.com/crossbeam-rs/crossbeam/issues/795
+pub(crate) fn timeout_to_deadline(timeout: Duration) -> Instant {
+    match Instant::now().checked_add(timeout) {
+        Some(deadline) => deadline,
+        None => Instant::now() + Duration::from_secs(86400 * 365 * 30),
+    }
+}
+
 /// A simple spinlock.
 pub(crate) struct Spinlock<T> {
     flag: AtomicBool,
diff --git a/crossbeam-utils/src/sync/parker.rs b/crossbeam-utils/src/sync/parker.rs
index 531f5a5fc..021e7c87c 100644
--- a/crossbeam-utils/src/sync/parker.rs
+++ b/crossbeam-utils/src/sync/parker.rs
@@ -121,7 +121,12 @@ impl Parker {
     /// p.park_timeout(Duration::from_millis(500));
     /// ```
     pub fn park_timeout(&self, timeout: Duration) {
-        self.park_deadline(Instant::now() + timeout)
+        // https://github.com/crossbeam-rs/crossbeam/issues/795
+        let deadline = match Instant::now().checked_add(timeout) {
+            Some(deadline) => deadline,
+            None => Instant::now() + Duration::from_secs(86400 * 365 * 30),
+        };
+        self.park_deadline(deadline)
     }
 
     /// Blocks the current thread until the token is made available, or until a certain deadline.