Adding upstream version 86.0.1.upstream/86.0.1upstream

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

1 files changed, 47 insertions, 0 deletions

diff --git a/third_party/rust/mio/src/sys/unix/dlsym.rs b/third_party/rust/mio/src/sys/unix/dlsym.rs
new file mode 100644
index 0000000000..e88c595fc9
--- /dev/null
+++ b/third_party/rust/mio/src/sys/unix/dlsym.rs
@@ -0,0 +1,47 @@
+use std::marker;
+use std::mem;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use libc;
+
+macro_rules! dlsym {
+    (fn $name:ident($($t:ty),*) -> $ret:ty) => (
+        #[allow(bad_style)]
+        static $name: ::sys::unix::dlsym::DlSym<unsafe extern fn($($t),*) -> $ret> =
+            ::sys::unix::dlsym::DlSym {
+                name: concat!(stringify!($name), "\0"),
+                addr: ::std::sync::atomic::ATOMIC_USIZE_INIT,
+                _marker: ::std::marker::PhantomData,
+            };
+    )
+}
+
+pub struct DlSym<F> {
+    pub name: &'static str,
+    pub addr: AtomicUsize,
+    pub _marker: marker::PhantomData<F>,
+}
+
+impl<F> DlSym<F> {
+    pub fn get(&self) -> Option<&F> {
+        assert_eq!(mem::size_of::<F>(), mem::size_of::<usize>());
+        unsafe {
+            if self.addr.load(Ordering::SeqCst) == 0 {
+                self.addr.store(fetch(self.name), Ordering::SeqCst);
+            }
+            if self.addr.load(Ordering::SeqCst) == 1 {
+                None
+            } else {
+                mem::transmute::<&AtomicUsize, Option<&F>>(&self.addr)
+            }
+        }
+    }
+}
+
+unsafe fn fetch(name: &str) -> usize {
+    assert_eq!(name.as_bytes()[name.len() - 1], 0);
+    match libc::dlsym(libc::RTLD_DEFAULT, name.as_ptr() as *const _) as usize {
+        0 => 1,
+        n => n,
+    }
+}