1 files changed, 125 insertions, 0 deletions
diff --git a/vendor/parking_lot_core-0.8.6/src/thread_parker/wasm_atomic.rs b/vendor/parking_lot_core-0.8.6/src/thread_parker/wasm_atomic.rs
new file mode 100644
index 000000000..2128e93cb
--- /dev/null
+++ b/vendor/parking_lot_core-0.8.6/src/thread_parker/wasm_atomic.rs
@@ -0,0 +1,125 @@
+// Copyright 2016 Amanieu d'Antras
+//
+// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
+// http://opensource.org/licenses/MIT>, at your option. This file may not be
+// copied, modified, or distributed except according to those terms.
+
+use cfg_if::cfg_if;
+use core::{
+    arch::wasm32,
+    sync::atomic::{AtomicI32, Ordering},
+};
+use instant::Instant;
+use std::time::Duration;
+use std::{convert::TryFrom, thread};
+
+cfg_if! {
+    if #[cfg(all(
+        target_arch = "wasm32",
+        target_os = "unknown",
+        target_vendor = "unknown"
+    ))] {
+        // This function serves as a polyfill for `Instant::checked_duration_since`, which is
+        // currently not implemented for wasm32-unknown-unknown.
+        // TODO: Remove this shim once it
+        fn checked_duration_since_now(other: Instant) -> Option<Duration> {
+            let now = Instant::now();
+
+            if other < now {
+                None
+            } else {
+                Some(other.duration_since(now))
+            }
+        }
+    } else {
+        // If we are not targeting wasm32, we can use the native `checked_duration_since`.
+        fn checked_duration_since_now(timeout: Instant) -> Option<Duration> {
+            timeout.checked_duration_since(Instant::now())
+        }
+    }
+}
+
+// Helper type for putting a thread to sleep until some other thread wakes it up
+pub struct ThreadParker {
+    parked: AtomicI32,
+}
+
+const UNPARKED: i32 = 0;
+const PARKED: i32 = 1;
+
+impl super::ThreadParkerT for ThreadParker {
+    type UnparkHandle = UnparkHandle;
+
+    const IS_CHEAP_TO_CONSTRUCT: bool = true;
+
+    #[inline]
+    fn new() -> ThreadParker {
+        ThreadParker {
+            parked: AtomicI32::new(UNPARKED),
+        }
+    }
+
+    #[inline]
+    unsafe fn prepare_park(&self) {
+        self.parked.store(PARKED, Ordering::Relaxed);
+    }
+
+    #[inline]
+    unsafe fn timed_out(&self) -> bool {
+        self.parked.load(Ordering::Relaxed) == PARKED
+    }
+
+    #[inline]
+    unsafe fn park(&self) {
+        while self.parked.load(Ordering::Acquire) == PARKED {
+            let r = wasm32::memory_atomic_wait32(self.ptr(), PARKED, -1);
+            // we should have either woken up (0) or got a not-equal due to a
+            // race (1). We should never time out (2)
+            debug_assert!(r == 0 || r == 1);
+        }
+    }
+
+    #[inline]
+    unsafe fn park_until(&self, timeout: Instant) -> bool {
+        while self.parked.load(Ordering::Acquire) == PARKED {
+            if let Some(left) = checked_duration_since_now(timeout) {
+                let nanos_left = i64::try_from(left.as_nanos()).unwrap_or(i64::max_value());
+                let r = wasm32::memory_atomic_wait32(self.ptr(), PARKED, nanos_left);
+                debug_assert!(r == 0 || r == 1 || r == 2);
+            } else {
+                return false;
+            }
+        }
+        true
+    }
+
+    #[inline]
+    unsafe fn unpark_lock(&self) -> UnparkHandle {
+        // We don't need to lock anything, just clear the state
+        self.parked.store(UNPARKED, Ordering::Release);
+        UnparkHandle(self.ptr())
+    }
+}
+
+impl ThreadParker {
+    #[inline]
+    fn ptr(&self) -> *mut i32 {
+        &self.parked as *const AtomicI32 as *mut i32
+    }
+}
+
+pub struct UnparkHandle(*mut i32);
+
+impl super::UnparkHandleT for UnparkHandle {
+    #[inline]
+    unsafe fn unpark(self) {
+        let num_notified = wasm32::memory_atomic_notify(self.0 as *mut i32, 1);
+        debug_assert!(num_notified == 0 || num_notified == 1);
+    }
+}
+
+#[inline]
+pub fn thread_yield() {
+    thread::yield_now();
+}