Implement the kqueue API (#488)

Add an eventvec for kqueue

Remove vscode from gitignore

Replace kqueue with an arbitrary FD

Improve FilterKind ergonomics

Add references to functions

Make kevent unsafe with RawFd

Kickstart my heart!

Empty commit to re-run the CI

Author: notgull

src/backend/libc/io/syscalls.rs

@@ -27,6 +27,18 @@ use core::ptr;
 #[cfg(all(feature = "fs", feature = "net"))]
 use libc_errno::errno;
 
+#[cfg(any(
+    target_os = "macos",
+    target_os = "ios",
+    target_os = "tvos",
+    target_os = "watchos",
+    target_os = "freebsd",
+    target_os = "dragonfly",
+    target_os = "openbsd",
+    target_os = "netbsd"
+))]
+use crate::io::kqueue::Event;
+
 pub(crate) fn read(fd: BorrowedFd<'_>, buf: &mut [u8]) -> io::Result<usize> {
     let nread = unsafe {
         ret_ssize_t(c::read(
@@ -450,6 +462,46 @@ pub(crate) fn ioctl_tiocnxcl(fd: BorrowedFd) -> io::Result<()> {
     unsafe { ret(c::ioctl(borrowed_fd(fd), c::TIOCNXCL as _)) }
 }
 
+#[cfg(any(
+    target_os = "macos",
+    target_os = "ios",
+    target_os = "tvos",
+    target_os = "watchos",
+    target_os = "freebsd",
+    target_os = "dragonfly",
+    target_os = "openbsd",
+    target_os = "netbsd"
+))]
+pub(crate) fn kqueue() -> io::Result<OwnedFd> {
+    unsafe { ret_owned_fd(c::kqueue()) }
+}
+
+#[cfg(any(
+    target_os = "macos",
+    target_os = "ios",
+    target_os = "tvos",
+    target_os = "watchos",
+    target_os = "freebsd",
+    target_os = "dragonfly",
+    target_os = "openbsd",
+    target_os = "netbsd"
+))]
+pub(crate) unsafe fn kevent(
+    kq: BorrowedFd<'_>,
+    changelist: &[Event],
+    eventlist: &mut [MaybeUninit<Event>],
+    timeout: Option<&c::timespec>,
+) -> io::Result<c::c_int> {
+    ret_c_int(c::kevent(
+        borrowed_fd(kq),
+        changelist.as_ptr() as *const _,
+        changelist.len() as _,
+        eventlist.as_mut_ptr() as *mut _,
+        eventlist.len() as _,
+        timeout.map_or(core::ptr::null(), |t| t as *const _),
+    ))
+}
+
 #[cfg(not(target_os = "wasi"))]
 pub(crate) fn pipe() -> io::Result<(OwnedFd, OwnedFd)> {
     unsafe {