1 files changed, 156 insertions, 0 deletions
diff --git a/vendor/parking_lot_core-0.8.6/src/thread_parker/linux.rs b/vendor/parking_lot_core-0.8.6/src/thread_parker/linux.rs
new file mode 100644
index 000000000..b22d0149f
--- /dev/null
+++ b/vendor/parking_lot_core-0.8.6/src/thread_parker/linux.rs
@@ -0,0 +1,156 @@
+// 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 core::{
+    ptr,
+    sync::atomic::{AtomicI32, Ordering},
+};
+use instant::Instant;
+use libc;
+use std::thread;
+
+// x32 Linux uses a non-standard type for tv_nsec in timespec.
+// See https://sourceware.org/bugzilla/show_bug.cgi?id=16437
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "32"))]
+#[allow(non_camel_case_types)]
+type tv_nsec_t = i64;
+#[cfg(not(all(target_arch = "x86_64", target_pointer_width = "32")))]
+#[allow(non_camel_case_types)]
+type tv_nsec_t = libc::c_long;
+
+fn errno() -> libc::c_int {
+    #[cfg(target_os = "linux")]
+    unsafe {
+        *libc::__errno_location()
+    }
+    #[cfg(target_os = "android")]
+    unsafe {
+        *libc::__errno()
+    }
+}
+
+// Helper type for putting a thread to sleep until some other thread wakes it up
+pub struct ThreadParker {
+    futex: AtomicI32,
+}
+
+impl super::ThreadParkerT for ThreadParker {
+    type UnparkHandle = UnparkHandle;
+
+    const IS_CHEAP_TO_CONSTRUCT: bool = true;
+
+    #[inline]
+    fn new() -> ThreadParker {
+        ThreadParker {
+            futex: AtomicI32::new(0),
+        }
+    }
+
+    #[inline]
+    unsafe fn prepare_park(&self) {
+        self.futex.store(1, Ordering::Relaxed);
+    }
+
+    #[inline]
+    unsafe fn timed_out(&self) -> bool {
+        self.futex.load(Ordering::Relaxed) != 0
+    }
+
+    #[inline]
+    unsafe fn park(&self) {
+        while self.futex.load(Ordering::Acquire) != 0 {
+            self.futex_wait(None);
+        }
+    }
+
+    #[inline]
+    unsafe fn park_until(&self, timeout: Instant) -> bool {
+        while self.futex.load(Ordering::Acquire) != 0 {
+            let now = Instant::now();
+            if timeout <= now {
+                return false;
+            }
+            let diff = timeout - now;
+            if diff.as_secs() as libc::time_t as u64 != diff.as_secs() {
+                // Timeout overflowed, just sleep indefinitely
+                self.park();
+                return true;
+            }
+            // SAFETY: libc::timespec is zero initializable.
+            let mut ts: libc::timespec = std::mem::zeroed();
+            ts.tv_sec = diff.as_secs() as libc::time_t;
+            ts.tv_nsec = diff.subsec_nanos() as tv_nsec_t;
+            self.futex_wait(Some(ts));
+        }
+        true
+    }
+
+    // Locks the parker to prevent the target thread from exiting. This is
+    // necessary to ensure that thread-local ThreadData objects remain valid.
+    // This should be called while holding the queue lock.
+    #[inline]
+    unsafe fn unpark_lock(&self) -> UnparkHandle {
+        // We don't need to lock anything, just clear the state
+        self.futex.store(0, Ordering::Release);
+
+        UnparkHandle { futex: &self.futex }
+    }
+}
+
+impl ThreadParker {
+    #[inline]
+    fn futex_wait(&self, ts: Option<libc::timespec>) {
+        let ts_ptr = ts
+            .as_ref()
+            .map(|ts_ref| ts_ref as *const _)
+            .unwrap_or(ptr::null());
+        let r = unsafe {
+            libc::syscall(
+                libc::SYS_futex,
+                &self.futex,
+                libc::FUTEX_WAIT | libc::FUTEX_PRIVATE_FLAG,
+                1,
+                ts_ptr,
+            )
+        };
+        debug_assert!(r == 0 || r == -1);
+        if r == -1 {
+            debug_assert!(
+                errno() == libc::EINTR
+                    || errno() == libc::EAGAIN
+                    || (ts.is_some() && errno() == libc::ETIMEDOUT)
+            );
+        }
+    }
+}
+
+pub struct UnparkHandle {
+    futex: *const AtomicI32,
+}
+
+impl super::UnparkHandleT for UnparkHandle {
+    #[inline]
+    unsafe fn unpark(self) {
+        // The thread data may have been freed at this point, but it doesn't
+        // matter since the syscall will just return EFAULT in that case.
+        let r = libc::syscall(
+            libc::SYS_futex,
+            self.futex,
+            libc::FUTEX_WAKE | libc::FUTEX_PRIVATE_FLAG,
+            1,
+        );
+        debug_assert!(r == 0 || r == 1 || r == -1);
+        if r == -1 {
+            debug_assert_eq!(errno(), libc::EFAULT);
+        }
+    }
+}
+
+#[inline]
+pub fn thread_yield() {
+    thread::yield_now();
+}