refactor: split cargo workspace

2026-06-05 11:56:21 -04:00 · 2026-06-05 11:56:21 -04:00 · 1c21bd1259
commit 1c21bd1259
parent 5db14936e7
695 changed files with 32023 additions and 44964 deletions
--- a/crates/utils/Cargo.toml
+++ b/crates/utils/Cargo.toml
@ -0,0 +1,26 @@
+[package]
+name = "jay-utils"
+version = "0.1.0"
+edition = "2024"
+license = "GPL-3.0-only"
+
+[dependencies]
+jay-config = { version = "1.10.0", path = "../jay-config" }
+
+ahash = "0.8.7"
+arrayvec = "0.7.4"
+bstr = { version = "1.9.0", default-features = false, features = ["std"] }
+cfg-if = "1.0.0"
+isnt = "0.2.0"
+linearize = { version = "0.1.3", features = ["derive"] }
+log = { version = "0.4.20", features = ["std"] }
+parking_lot = "0.12.1"
+rand = "0.10.0"
+serde = { version = "1.0.196", features = ["derive"] }
+smallvec = { version = "1.11.1", features = ["const_generics", "const_new", "union"] }
+thiserror = "2.0.11"
+uapi = "0.2.13"
+
+[features]
+it = []
+rc_tracking = []
--- a/crates/utils/src/array.rs
+++ b/crates/utils/src/array.rs
@ -0,0 +1,11 @@
+pub fn from_fn<F, T, const N: usize>(mut cb: F) -> [T; N]
+where
+    F: FnMut(usize) -> T,
+{
+    let mut idx = 0;
+    [(); N].map(|_| {
+        let res = cb(idx);
+        idx += 1;
+        res
+    })
+}
--- a/crates/utils/src/array_to_tuple.rs
+++ b/crates/utils/src/array_to_tuple.rs
@ -0,0 +1,28 @@
+pub trait ArrayToTuple {
+    type Tuple;
+
+    fn to_tuple(self) -> Self::Tuple;
+}
+
+macro_rules! ignore {
+    ($t:tt) => {
+        T
+    };
+}
+
+macro_rules! array_to_tuple {
+    ($n:expr, $($field:ident,)*) => {
+        impl<T> ArrayToTuple for [T; $n] {
+            type Tuple = ($(ignore!($field),)*);
+
+            fn to_tuple(self) -> Self::Tuple {
+                let [$($field,)*] = self;
+                #[allow(clippy::allow_attributes)]
+                #[allow(clippy::unused_unit)]
+                ($($field,)*)
+            }
+        }
+    };
+}
+
+array_to_tuple!(2, t1, t2,);
--- a/crates/utils/src/asyncevent.rs
+++ b/crates/utils/src/asyncevent.rs
@ -0,0 +1,60 @@
+use {
+    crate::numcell::NumCell,
+    std::{
+        cell::Cell,
+        fmt::{Debug, Formatter},
+        future::Future,
+        pin::Pin,
+        task::{Context, Poll, Waker},
+    },
+};
+
+#[derive(Default)]
+pub struct AsyncEvent {
+    triggers: NumCell<u32>,
+    waker: Cell<Option<Waker>>,
+}
+
+impl Debug for AsyncEvent {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("AsyncEvent")
+            .field("triggers", &self.triggers.get())
+            .finish_non_exhaustive()
+    }
+}
+
+impl AsyncEvent {
+    pub fn clear(&self) {
+        self.triggers.set(0);
+        self.waker.take();
+    }
+
+    pub fn trigger(&self) {
+        if self.triggers.fetch_add(1) == 0
+            && let Some(waker) = self.waker.take()
+        {
+            waker.wake();
+        }
+    }
+
+    pub fn triggered(&self) -> AsyncEventTriggered<'_> {
+        AsyncEventTriggered { ae: self }
+    }
+}
+
+pub struct AsyncEventTriggered<'a> {
+    ae: &'a AsyncEvent,
+}
+
+impl<'a> Future for AsyncEventTriggered<'a> {
+    type Output = ();
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        if self.ae.triggers.replace(0) == 0 {
+            self.ae.waker.set(Some(cx.waker().clone()));
+            Poll::Pending
+        } else {
+            Poll::Ready(())
+        }
+    }
+}
--- a/crates/utils/src/atomic_enum.rs
+++ b/crates/utils/src/atomic_enum.rs
@ -0,0 +1,42 @@
+use {
+    linearize::Linearize,
+    std::{
+        marker::PhantomData,
+        sync::atomic::{AtomicUsize, Ordering},
+    },
+};
+
+pub struct AtomicEnum<T> {
+    v: AtomicUsize,
+    _phantom: PhantomData<T>,
+}
+
+impl<T> Default for AtomicEnum<T>
+where
+    T: Default + Linearize + Copy,
+{
+    fn default() -> Self {
+        Self::new(T::default())
+    }
+}
+
+impl<T> AtomicEnum<T>
+where
+    T: Linearize + Copy,
+{
+    pub fn new(t: T) -> Self {
+        Self {
+            v: AtomicUsize::new(t.linearize()),
+            _phantom: Default::default(),
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn load(&self, ordering: Ordering) -> T {
+        unsafe { T::from_linear_unchecked(self.v.load(ordering)) }
+    }
+
+    pub fn store(&self, t: T, ordering: Ordering) {
+        self.v.store(t.linearize(), ordering);
+    }
+}
--- a/crates/utils/src/binary_search_map.rs
+++ b/crates/utils/src/binary_search_map.rs
@ -0,0 +1,219 @@
+use {
+    crate::ptr_ext::{MutPtrExt, PtrExt},
+    smallvec::SmallVec,
+    std::{
+        fmt::{Debug, Formatter},
+        mem,
+    },
+};
+
+pub struct BinarySearchMap<K, V, const N: usize> {
+    m: SmallVec<[(K, V); N]>,
+}
+
+impl<K: Debug, V: Debug, const N: usize> Debug for BinarySearchMap<K, V, N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_map()
+            .entries(self.m.iter().map(|e| (&e.0, &e.1)))
+            .finish()
+    }
+}
+
+impl<K, V, const N: usize> Default for BinarySearchMap<K, V, N> {
+    fn default() -> Self {
+        Self {
+            m: Default::default(),
+        }
+    }
+}
+
+impl<K, V, const N: usize> BinarySearchMap<K, V, N> {
+    pub fn new_with(k: K, v: V) -> Self {
+        let mut sv = SmallVec::new();
+        sv.push((k, v));
+        Self { m: sv }
+    }
+
+    pub fn new() -> Self {
+        Self {
+            m: SmallVec::new_const(),
+        }
+    }
+
+    pub fn len(&self) -> usize {
+        self.m.len()
+    }
+
+    fn pos(&self, k: &K) -> Result<usize, usize>
+    where
+        K: Ord + Eq,
+    {
+        self.m.binary_search_by(|(c, _)| c.cmp(k))
+    }
+
+    pub fn contains(&self, k: &K) -> bool
+    where
+        K: Ord + Eq,
+    {
+        self.pos(k).is_ok()
+    }
+
+    pub fn not_contains(&self, k: &K) -> bool
+    where
+        K: Ord + Eq,
+    {
+        !self.contains(k)
+    }
+
+    pub fn insert(&mut self, k: K, v: V) -> Option<V>
+    where
+        K: Ord + Eq,
+    {
+        match self.pos(&k) {
+            Ok(p) => Some(mem::replace(&mut self.m[p], (k, v)).1),
+            Err(p) => {
+                self.m.insert(p, (k, v));
+                None
+            }
+        }
+    }
+
+    pub fn get(&self, k: &K) -> Option<&V>
+    where
+        K: Ord + Eq,
+    {
+        self.pos(k).ok().map(|p| &self.m[p].1)
+    }
+
+    pub fn get_mut(&mut self, k: &K) -> Option<&mut V>
+    where
+        K: Ord + Eq,
+    {
+        self.pos(k).ok().map(|p| &mut self.m[p].1)
+    }
+
+    pub fn get_or_default_mut(&mut self, k: K) -> &mut V
+    where
+        K: Ord + Eq,
+        V: Default,
+    {
+        self.get_or_insert_with(k, || V::default())
+    }
+
+    pub fn get_or_insert_with<F>(&mut self, k: K, f: F) -> &mut V
+    where
+        K: Ord + Eq,
+        F: FnOnce() -> V,
+    {
+        let p = match self.pos(&k) {
+            Ok(p) => return &mut self.m[p].1,
+            Err(p) => p,
+        };
+        self.m.insert(p, (k, f()));
+        &mut self.m[p].1
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.m.is_empty()
+    }
+
+    pub fn remove(&mut self, k: &K) -> Option<V>
+    where
+        K: Ord + Eq,
+    {
+        if let Ok(p) = self.pos(k) {
+            return Some(self.m.remove(p).1);
+        }
+        None
+    }
+
+    pub fn clear(&mut self) {
+        let _v = mem::replace(&mut self.m, SmallVec::new());
+    }
+
+    pub fn take(&mut self) -> SmallVec<[(K, V); N]> {
+        mem::take(&mut self.m)
+    }
+
+    pub fn iter<'a>(&'a self) -> BinarySearchMapIter<'a, K, V, N> {
+        BinarySearchMapIter { pos: 0, map: self }
+    }
+
+    pub fn values<'a>(&'a self) -> impl Iterator<Item = &'a V> + 'a {
+        self.iter().map(|(_, v)| v)
+    }
+
+    pub fn iter_mut<'a>(&'a mut self) -> BinarySearchMapMutIterMut<'a, K, V, N> {
+        BinarySearchMapMutIterMut { pos: 0, map: self }
+    }
+
+    pub fn values_mut<'a>(&'a mut self) -> impl Iterator<Item = &'a mut V> + 'a {
+        self.iter_mut().map(|(_, v)| v)
+    }
+
+    pub fn remove_if<F: FnMut(&K, &V) -> bool>(&mut self, mut f: F) {
+        let mut i = 0;
+        while i < self.m.len() {
+            let (k, v) = &self.m[i];
+            if f(k, v) {
+                self.m.remove(i);
+            } else {
+                i += 1;
+            }
+        }
+    }
+}
+
+impl<'a, K: Copy, V, const N: usize> IntoIterator for &'a BinarySearchMap<K, V, N> {
+    type Item = (&'a K, &'a V);
+    type IntoIter = BinarySearchMapIter<'a, K, V, N>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        BinarySearchMapIter { pos: 0, map: self }
+    }
+}
+
+impl<'a, K: Copy, V, const N: usize> IntoIterator for &'a mut BinarySearchMap<K, V, N> {
+    type Item = (&'a K, &'a mut V);
+    type IntoIter = BinarySearchMapMutIterMut<'a, K, V, N>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        BinarySearchMapMutIterMut { pos: 0, map: self }
+    }
+}
+
+pub struct BinarySearchMapIter<'a, K, V, const N: usize> {
+    pos: usize,
+    map: &'a BinarySearchMap<K, V, N>,
+}
+
+impl<'a, K, V, const N: usize> Iterator for BinarySearchMapIter<'a, K, V, N> {
+    type Item = (&'a K, &'a V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.pos >= self.map.m.len() {
+            return None;
+        }
+        let (k, v) = &self.map.m[self.pos];
+        self.pos += 1;
+        Some((k, v))
+    }
+}
+
+pub struct BinarySearchMapMutIterMut<'a, K, V, const N: usize> {
+    pos: usize,
+    map: &'a mut BinarySearchMap<K, V, N>,
+}
+
+impl<'a, K, V, const N: usize> Iterator for BinarySearchMapMutIterMut<'a, K, V, N> {
+    type Item = (&'a K, &'a mut V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.pos >= self.map.m.len() {
+            return None;
+        }
+        let (k, v) = &mut self.map.m[self.pos];
+        self.pos += 1;
+        unsafe { Some(((k as *const K).deref(), (v as *mut V).deref_mut())) }
+    }
+}
--- a/crates/utils/src/bitfield.rs
+++ b/crates/utils/src/bitfield.rs
@ -0,0 +1,37 @@
+#![allow(dead_code)]
+
+const SEG_SIZE: usize = usize::BITS as usize;
+
+#[derive(Default)]
+pub struct Bitfield {
+    vals: Vec<usize>,
+}
+
+impl Bitfield {
+    pub fn take(&mut self, val: u32) {
+        let idx = val as usize / SEG_SIZE;
+        let pos = val as usize % SEG_SIZE;
+        while self.vals.len() <= idx {
+            self.vals.push(!0);
+        }
+        self.vals[idx] &= !(1 << pos);
+    }
+
+    pub fn acquire(&mut self) -> u32 {
+        for (idx, n) in self.vals.iter_mut().enumerate() {
+            if *n != 0 {
+                let pos = n.trailing_zeros();
+                *n &= !(1 << pos);
+                return (idx * SEG_SIZE) as u32 + pos;
+            }
+        }
+        self.vals.push(!1);
+        ((self.vals.len() - 1) * SEG_SIZE) as u32
+    }
+
+    pub fn release(&mut self, val: u32) {
+        let idx = val as usize / SEG_SIZE;
+        let pos = val as usize % SEG_SIZE;
+        self.vals[idx] |= 1 << pos;
+    }
+}
--- a/crates/utils/src/bitflags.rs
+++ b/crates/utils/src/bitflags.rs
@ -0,0 +1,32 @@
+pub trait BitflagsExt {
+    fn contains(self, other: Self) -> bool;
+    fn not_contains(self, other: Self) -> bool;
+    fn intersects(self, other: Self) -> bool;
+}
+
+macro_rules! num {
+    ($ty:ident) => {
+        impl BitflagsExt for $ty {
+            fn contains(self, other: Self) -> bool {
+                self & other == other
+            }
+
+            fn not_contains(self, other: Self) -> bool {
+                self & other != other
+            }
+
+            fn intersects(self, other: Self) -> bool {
+                self & other != 0
+            }
+        }
+    };
+}
+
+num!(u8);
+num!(u16);
+num!(u32);
+num!(u64);
+num!(i8);
+num!(i16);
+num!(i32);
+num!(i64);
--- a/crates/utils/src/buf.rs
+++ b/crates/utils/src/buf.rs
@ -0,0 +1,328 @@
+use {
+    crate::{numcell::NumCell, ptr_ext::PtrExt},
+    std::{
+        alloc::Layout,
+        cmp,
+        collections::Bound,
+        fmt::Arguments,
+        io::{self, Write},
+        marker::PhantomData,
+        mem,
+        ops::{Deref, DerefMut, Range, RangeBounds},
+        ptr::NonNull,
+        slice,
+    },
+    uapi::Pod,
+};
+
+const METADATA_SIZE: u32 = 8;
+const METADATA_ALIGN: usize = 4;
+const SIZE_OFF: u32 = 0;
+const RC_OFF: u32 = 4;
+const RC_OFF_INV: u32 = METADATA_SIZE - RC_OFF;
+const SIZE_OFF_INV: u32 = METADATA_SIZE - SIZE_OFF;
+
+pub struct Buf {
+    storage: NonNull<u8>,
+    range: Range<u32>,
+}
+
+impl Buf {
+    pub fn from_slice(vec: &[u8]) -> Buf {
+        let len = vec.len();
+        assert!(len <= (u32::MAX - METADATA_SIZE) as usize);
+        let len = len as u32;
+        let size = len + METADATA_SIZE;
+        let layout = Layout::from_size_align(size as _, METADATA_ALIGN).unwrap();
+        let ptr = unsafe { std::alloc::alloc(layout) };
+        if ptr.is_null() {
+            std::alloc::handle_alloc_error(layout);
+        }
+        unsafe {
+            *ptr.cast::<u32>() = size;
+            *ptr.add(RC_OFF as _).cast::<u32>() = 1;
+            let mut buf = Buf {
+                storage: NonNull::new_unchecked(ptr.add(METADATA_SIZE as _)),
+                range: Range { start: 0, end: len },
+            };
+            buf[..].copy_from_slice(vec);
+            buf
+        }
+    }
+
+    pub fn new(len: usize) -> Buf {
+        assert!(len <= (u32::MAX - METADATA_SIZE) as usize);
+        let len = len as u32;
+        let size = len + METADATA_SIZE;
+        let layout = Layout::from_size_align(size as _, METADATA_ALIGN).unwrap();
+        let ptr = unsafe { std::alloc::alloc_zeroed(layout) };
+        if ptr.is_null() {
+            std::alloc::handle_alloc_error(layout);
+        }
+        unsafe {
+            *ptr.cast::<u32>() = size;
+            *ptr.add(RC_OFF as _).cast::<u32>() = 1;
+            Buf {
+                storage: NonNull::new_unchecked(ptr.add(METADATA_SIZE as _)),
+                range: Range { start: 0, end: len },
+            }
+        }
+    }
+
+    pub fn clone(&mut self) -> Buf {
+        self.rc().fetch_add(1);
+        Buf {
+            storage: self.storage,
+            range: self.range.clone(),
+        }
+    }
+
+    pub fn slice(&mut self, range: impl RangeBounds<usize>) -> Buf {
+        let start = match range.start_bound() {
+            Bound::Included(&n) => n,
+            Bound::Excluded(&n) => n.wrapping_add(1),
+            Bound::Unbounded => 0,
+        };
+        let end = match range.end_bound() {
+            Bound::Included(&n) => n.wrapping_add(1),
+            Bound::Excluded(&n) => n,
+            Bound::Unbounded => self.len(),
+        };
+        self.slice_(start as _, end as _)
+    }
+
+    fn slice_(&mut self, start: u32, end: u32) -> Buf {
+        assert!(start <= end);
+        assert!(end <= self.len32());
+        self.rc().fetch_add(1);
+        Buf {
+            storage: self.storage,
+            range: Range {
+                start: self.range.start + start,
+                end: self.range.start + end,
+            },
+        }
+    }
+
+    fn rc(&self) -> &NumCell<u32> {
+        unsafe {
+            self.storage
+                .as_ptr()
+                .sub(RC_OFF_INV as _)
+                .cast::<NumCell<u32>>()
+                .deref()
+        }
+    }
+
+    fn assert_unique(&self) {
+        assert_eq!(self.rc().get(), 1);
+    }
+
+    pub fn len32(&self) -> u32 {
+        self.range.end - self.range.start
+    }
+
+    pub fn len(&self) -> usize {
+        self.len32() as _
+    }
+
+    fn size32(&self) -> u32 {
+        unsafe {
+            *self
+                .storage
+                .as_ptr()
+                .sub(SIZE_OFF_INV as _)
+                .cast::<u32>()
+                .deref()
+        }
+    }
+
+    pub fn cap32(&self) -> u32 {
+        self.size32() - METADATA_SIZE
+    }
+
+    pub fn as_ptr(&self) -> *mut u8 {
+        unsafe { self.storage.as_ptr().add(self.range.start as _) }
+    }
+
+    pub fn write_fmt(&mut self, args: Arguments) -> Result<Self, io::Error> {
+        let cap = self.len();
+        let mut buf = self.deref_mut();
+        buf.write_fmt(args)?;
+        let len = cap - buf.len();
+        Ok(self.slice(..len))
+    }
+
+    pub fn into_full(self) -> Self {
+        let new = Self {
+            storage: self.storage,
+            range: 0..self.cap32(),
+        };
+        mem::forget(self);
+        new
+    }
+
+    fn as_slice(&self) -> &[u8] {
+        unsafe { slice::from_raw_parts(self.as_ptr(), self.len()) }
+    }
+
+    fn as_slice_mut(&mut self) -> &mut [u8] {
+        unsafe { slice::from_raw_parts_mut(self.as_ptr(), self.len()) }
+    }
+}
+
+impl Default for Buf {
+    fn default() -> Self {
+        Self::new(0)
+    }
+}
+
+impl Deref for Buf {
+    type Target = [u8];
+
+    fn deref(&self) -> &Self::Target {
+        self.assert_unique();
+        self.as_slice()
+    }
+}
+
+impl DerefMut for Buf {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.assert_unique();
+        self.as_slice_mut()
+    }
+}
+
+impl Drop for Buf {
+    fn drop(&mut self) {
+        unsafe {
+            let prev = self.rc().fetch_sub(1);
+            if prev != 1 {
+                return;
+            }
+            let ptr = self.storage.as_ptr().sub(METADATA_SIZE as _).cast::<u32>();
+            let size = *ptr as _;
+            let layout = Layout::from_size_align_unchecked(size, METADATA_ALIGN);
+            std::alloc::dealloc(ptr as _, layout);
+        }
+    }
+}
+
+pub struct DynamicBuf {
+    buf: Buf,
+    len: usize,
+}
+
+impl DynamicBuf {
+    pub fn new() -> Self {
+        Self {
+            buf: Buf::new(0),
+            len: 0,
+        }
+    }
+
+    pub fn from_buf(buf: Buf) -> Self {
+        buf.assert_unique();
+        Self {
+            buf: buf.into_full(),
+            len: 0,
+        }
+    }
+
+    pub fn unwrap(mut self) -> Buf {
+        self.buf.slice(..self.len)
+    }
+
+    pub fn len(&self) -> usize {
+        self.len
+    }
+
+    pub fn reserve(&mut self, n: usize) {
+        if self.buf.len() - self.len < n {
+            let cap = self.len.checked_add(n).unwrap();
+            let cap = cmp::max(self.buf.len() * 2, cap);
+            let mut new = Buf::new(cap);
+            new[..self.len].copy_from_slice(&self.buf[..self.len]);
+            self.buf = new;
+        }
+    }
+
+    pub fn extend_from_slice(&mut self, buf: &[u8]) {
+        self.reserve(buf.len());
+        self.buf.as_slice_mut()[self.len..self.len + buf.len()].copy_from_slice(buf);
+        self.len += buf.len();
+    }
+
+    pub fn push(&mut self, b: u8) {
+        self.extend_from_slice(&[b]);
+    }
+
+    pub fn clear(&mut self) {
+        self.len = 0;
+    }
+
+    pub fn borrow(&mut self) -> BorrowedBuf<'_> {
+        BorrowedBuf {
+            buf: self.buf.slice(..self.len),
+            _phantom: Default::default(),
+        }
+    }
+}
+
+pub struct BorrowedBuf<'a> {
+    pub buf: Buf,
+    _phantom: PhantomData<&'a mut DynamicBuf>,
+}
+
+impl<'a> Drop for BorrowedBuf<'a> {
+    fn drop(&mut self) {
+        assert_eq!(self.buf.rc().get(), 2);
+    }
+}
+
+impl Write for DynamicBuf {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Deref for DynamicBuf {
+    type Target = [u8];
+
+    fn deref(&self) -> &Self::Target {
+        self.buf.as_slice()
+    }
+}
+
+impl DerefMut for DynamicBuf {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.buf.as_slice_mut()
+    }
+}
+
+pub struct TypedBuf<T: Pod> {
+    buf: Buf,
+    _phantom: PhantomData<T>,
+}
+
+impl<T: Pod> TypedBuf<T> {
+    pub fn new() -> Self {
+        Self {
+            buf: Buf::new(size_of::<T>()),
+            _phantom: Default::default(),
+        }
+    }
+
+    pub fn buf(&mut self) -> Buf {
+        self.buf.clone()
+    }
+
+    pub fn t(&self) -> T {
+        uapi::pod_read(&self.buf[..]).unwrap()
+    }
+}
--- a/crates/utils/src/cell_ext.rs
+++ b/crates/utils/src/cell_ext.rs
@ -0,0 +1,16 @@
+use {crate::ptr_ext::PtrExt, std::cell::Cell};
+
+pub trait CellExt {
+    fn is_some(&self) -> bool;
+    fn is_none(&self) -> bool;
+}
+
+impl<T> CellExt for Cell<Option<T>> {
+    fn is_some(&self) -> bool {
+        unsafe { self.as_ptr().deref().is_some() }
+    }
+
+    fn is_none(&self) -> bool {
+        !self.is_some()
+    }
+}
--- a/crates/utils/src/clonecell.rs
+++ b/crates/utils/src/clonecell.rs
@ -0,0 +1,98 @@
+use {
+    crate::ptr_ext::{MutPtrExt, PtrExt},
+    jay_config::{keyboard::mods::Modifiers, window::Window},
+    std::{
+        cell::UnsafeCell,
+        fmt::{Debug, Formatter},
+        mem,
+        rc::{Rc, Weak},
+        sync::Arc,
+    },
+};
+
+pub struct CloneCell<T> {
+    data: UnsafeCell<T>,
+}
+
+impl<T: UnsafeCellCloneSafe> Clone for CloneCell<T> {
+    fn clone(&self) -> Self {
+        Self {
+            data: UnsafeCell::new(self.get()),
+        }
+    }
+}
+
+impl<T: UnsafeCellCloneSafe + Debug> Debug for CloneCell<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.get().fmt(f)
+    }
+}
+
+impl<T> CloneCell<T> {
+    pub const fn new(t: T) -> Self {
+        Self {
+            data: UnsafeCell::new(t),
+        }
+    }
+
+    #[inline(always)]
+    pub fn get(&self) -> T
+    where
+        T: UnsafeCellCloneSafe,
+    {
+        unsafe { self.data.get().deref().clone() }
+    }
+
+    #[inline(always)]
+    pub fn set(&self, t: T) -> T {
+        unsafe { mem::replace(self.data.get().deref_mut(), t) }
+    }
+
+    #[inline(always)]
+    pub fn take(&self) -> T
+    where
+        T: Default,
+    {
+        self.set(T::default())
+    }
+}
+
+impl<T> CloneCell<Option<T>> {
+    #[inline(always)]
+    pub fn is_some(&self) -> bool {
+        unsafe { self.data.get().deref().is_some() }
+    }
+
+    #[inline(always)]
+    pub fn is_none(&self) -> bool {
+        unsafe { self.data.get().deref().is_none() }
+    }
+}
+
+impl<T: Default> Default for CloneCell<T> {
+    fn default() -> Self {
+        Self::new(Default::default())
+    }
+}
+
+pub unsafe trait UnsafeCellCloneSafe: Clone {}
+
+unsafe impl<T: UnsafeCellCloneSafe> UnsafeCellCloneSafe for Option<T> {}
+
+unsafe impl<T: ?Sized> UnsafeCellCloneSafe for Rc<T> {}
+unsafe impl<T: ?Sized> UnsafeCellCloneSafe for Weak<T> {}
+unsafe impl<T: ?Sized> UnsafeCellCloneSafe for Arc<T> {}
+
+unsafe impl UnsafeCellCloneSafe for () {}
+unsafe impl UnsafeCellCloneSafe for u64 {}
+unsafe impl UnsafeCellCloneSafe for i32 {}
+unsafe impl UnsafeCellCloneSafe for u32 {}
+unsafe impl UnsafeCellCloneSafe for usize {}
+
+unsafe impl<A: UnsafeCellCloneSafe, B: UnsafeCellCloneSafe> UnsafeCellCloneSafe for (A, B) {}
+
+unsafe impl UnsafeCellCloneSafe for Modifiers {}
+
+unsafe impl UnsafeCellCloneSafe for Window {}
+
+unsafe impl<T> UnsafeCellCloneSafe for crate::linkedlist::NodeRef<T> {}
--- a/crates/utils/src/compat.rs
+++ b/crates/utils/src/compat.rs
@ -0,0 +1,11 @@
+use {cfg_if::cfg_if, uapi::c};
+
+cfg_if! {
+    if #[cfg(target_env = "musl")] {
+        pub type IoctlNumber = c::c_int;
+        pub type IovLength = c::c_int;
+    } else {
+        pub type IoctlNumber = c::c_ulong;
+        pub type IovLength = usize;
+    }
+}
--- a/crates/utils/src/copyhashmap.rs
+++ b/crates/utils/src/copyhashmap.rs
@ -0,0 +1,126 @@
+use {
+    crate::{
+        clonecell::UnsafeCellCloneSafe,
+        ptr_ext::{MutPtrExt, PtrExt},
+    },
+    ahash::AHashMap,
+    std::{
+        borrow::Borrow,
+        cell::UnsafeCell,
+        fmt::{Debug, Formatter},
+        hash::Hash,
+        mem,
+        ops::{Deref, DerefMut},
+    },
+};
+
+pub struct CopyHashMap<K, V> {
+    map: UnsafeCell<AHashMap<K, V>>,
+}
+
+impl<K: Debug, V: Debug> Debug for CopyHashMap<K, V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.map.fmt(f)
+    }
+}
+
+impl<K, V> Default for CopyHashMap<K, V> {
+    fn default() -> Self {
+        Self {
+            map: Default::default(),
+        }
+    }
+}
+
+impl<K: Eq + Hash, V> CopyHashMap<K, V> {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn set(&self, k: K, v: V) -> Option<V> {
+        unsafe { self.map.get().deref_mut().insert(k, v) }
+    }
+
+    pub fn get<Q>(&self, k: &Q) -> Option<V>
+    where
+        V: UnsafeCellCloneSafe,
+        Q: Hash + Eq + ?Sized,
+        K: Borrow<Q>,
+    {
+        unsafe { self.map.get().deref().get(k).cloned() }
+    }
+
+    pub fn remove<Q>(&self, k: &Q) -> Option<V>
+    where
+        Q: Hash + Eq + ?Sized,
+        K: Borrow<Q>,
+    {
+        unsafe { self.map.get().deref_mut().remove(k) }
+    }
+
+    pub fn contains<Q>(&self, k: &Q) -> bool
+    where
+        Q: Hash + Eq + ?Sized,
+        K: Borrow<Q>,
+    {
+        unsafe { self.map.get().deref().contains_key(k) }
+    }
+
+    pub fn not_contains<Q>(&self, k: &Q) -> bool
+    where
+        Q: Hash + Eq + ?Sized,
+        K: Borrow<Q>,
+    {
+        !self.contains(k)
+    }
+
+    pub fn lock(&self) -> Locked<'_, K, V> {
+        Locked {
+            source: self,
+            map: self.clear(),
+        }
+    }
+
+    pub fn clear(&self) -> AHashMap<K, V> {
+        unsafe { mem::take(self.map.get().deref_mut()) }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        unsafe { self.map.get().deref().is_empty() }
+    }
+
+    pub fn is_not_empty(&self) -> bool {
+        !self.is_empty()
+    }
+
+    pub fn len(&self) -> usize {
+        unsafe { self.map.get().deref().len() }
+    }
+}
+
+pub struct Locked<'a, K, V> {
+    source: &'a CopyHashMap<K, V>,
+    map: AHashMap<K, V>,
+}
+
+impl<'a, K, V> Drop for Locked<'a, K, V> {
+    fn drop(&mut self) {
+        unsafe {
+            mem::swap(&mut self.map, self.source.map.get().deref_mut());
+        }
+    }
+}
+
+impl<'a, K, V> Deref for Locked<'a, K, V> {
+    type Target = AHashMap<K, V>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.map
+    }
+}
+
+impl<'a, K, V> DerefMut for Locked<'a, K, V> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.map
+    }
+}
--- a/crates/utils/src/double_buffered.rs
+++ b/crates/utils/src/double_buffered.rs
@ -0,0 +1,36 @@
+use std::{cell::Cell, ops::Deref};
+
+#[derive(Default)]
+pub struct DoubleBuffered<T> {
+    bufs: [T; 2],
+    front: Cell<usize>,
+}
+
+impl<T> DoubleBuffered<T> {
+    pub fn new(bufs: [T; 2]) -> Self {
+        Self {
+            bufs,
+            front: Cell::new(0),
+        }
+    }
+
+    pub fn front(&self) -> &T {
+        unsafe { self.bufs.get_unchecked(self.front.get()) }
+    }
+
+    pub fn back(&self) -> &T {
+        unsafe { self.bufs.get_unchecked(1 - self.front.get()) }
+    }
+
+    pub fn flip(&self) {
+        self.front.set(1 - self.front.get());
+    }
+}
+
+impl<T> Deref for DoubleBuffered<T> {
+    type Target = [T; 2];
+
+    fn deref(&self) -> &Self::Target {
+        &self.bufs
+    }
+}
--- a/crates/utils/src/errorfmt.rs
+++ b/crates/utils/src/errorfmt.rs
@ -0,0 +1,23 @@
+use std::{
+    error::Error,
+    fmt::{Display, Formatter},
+};
+
+pub struct ErrorFmt<E>(pub E);
+
+impl<E: Error> Display for ErrorFmt<E> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let mut e_opt = Some(&self.0 as &dyn Error);
+        let mut first = true;
+        while let Some(e) = e_opt {
+            if first {
+                write!(f, "{}", e)?;
+                first = false;
+            } else {
+                write!(f, ": {}", e)?;
+            }
+            e_opt = e.source();
+        }
+        Ok(())
+    }
+}
--- a/crates/utils/src/event_listener.rs
+++ b/crates/utils/src/event_listener.rs
@ -0,0 +1,153 @@
+use {
+    crate::{
+        linkedlist::{LinkedList, LinkedListIter, LinkedNode},
+        queue::AsyncQueue,
+    },
+    std::{
+        cell::Cell,
+        ops::Deref,
+        rc::{Rc, Weak},
+    },
+};
+
+pub async fn handle_lazy_event_sources_of(sources: &LazyEventSources) {
+    loop {
+        let source = sources.queue.pop().await;
+        source.queued.set(false);
+        for listener in source.listeners.iter() {
+            listener.triggered();
+        }
+    }
+}
+
+pub struct EventSource<T: ?Sized> {
+    listeners: LinkedList<Weak<T>>,
+    on_attach: Cell<Option<Box<dyn FnOnce()>>>,
+}
+
+pub struct EventListener<T: ?Sized> {
+    link: LinkedNode<Weak<T>>,
+}
+
+#[derive(Default)]
+pub struct LazyEventSources {
+    queue: AsyncQueue<Rc<LazyEventSource>>,
+}
+
+pub trait LazyEventSourceListener {
+    fn triggered(self: Rc<Self>);
+}
+
+pub struct LazyEventSource {
+    sources: Rc<LazyEventSources>,
+    queued: Cell<bool>,
+    listeners: EventSource<dyn LazyEventSourceListener>,
+}
+
+impl<T: ?Sized> Default for EventSource<T> {
+    fn default() -> Self {
+        Self {
+            listeners: Default::default(),
+            on_attach: Default::default(),
+        }
+    }
+}
+
+impl<T: ?Sized> EventSource<T> {
+    pub fn clear(&self) {
+        self.on_attach.take();
+    }
+
+    pub fn iter(&self) -> EventSourceIter<T> {
+        EventSourceIter {
+            iter: self.listeners.iter(),
+        }
+    }
+
+    pub fn has_listeners(&self) -> bool {
+        self.listeners.is_not_empty()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.listeners.is_empty()
+    }
+
+    pub fn on_attach(&self, f: Box<dyn FnOnce()>) {
+        self.on_attach.set(Some(f));
+    }
+}
+
+pub struct EventSourceIter<T: ?Sized> {
+    iter: LinkedListIter<Weak<T>>,
+}
+
+impl<T: ?Sized> Iterator for EventSourceIter<T> {
+    type Item = Rc<T>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        for weak in self.iter.by_ref() {
+            if let Some(t) = weak.upgrade() {
+                return Some(t);
+            }
+        }
+        None
+    }
+}
+
+impl<T: ?Sized> EventListener<T> {
+    pub fn new(t: Weak<T>) -> Self {
+        Self {
+            link: LinkedNode::detached(t),
+        }
+    }
+
+    pub fn attach(&self, source: &EventSource<T>) {
+        source.listeners.add_last_existing(&self.link);
+        if let Some(on_attach) = source.on_attach.take() {
+            on_attach();
+        }
+    }
+
+    pub fn detach(&self) {
+        self.link.detach();
+    }
+
+    pub fn get(&self) -> Option<Rc<T>> {
+        self.link.upgrade()
+    }
+}
+
+impl Deref for LazyEventSource {
+    type Target = EventSource<dyn LazyEventSourceListener>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.listeners
+    }
+}
+
+impl LazyEventSource {
+    pub fn trigger(self: &Rc<Self>) {
+        if self.listeners.is_empty() {
+            return;
+        }
+        if self.queued.replace(true) {
+            return;
+        }
+        self.sources.queue.push(self.clone());
+    }
+}
+
+impl LazyEventSources {
+    #[allow(dead_code)]
+    pub fn create_source(self: &Rc<Self>) -> Rc<LazyEventSource> {
+        Rc::new(LazyEventSource {
+            sources: self.clone(),
+            queued: Default::default(),
+            listeners: Default::default(),
+        })
+    }
+
+    pub fn clear(&self) {
+        self.queue.clear();
+    }
+}
--- a/crates/utils/src/fdcloser.rs
+++ b/crates/utils/src/fdcloser.rs
@ -0,0 +1,52 @@
+use {
+    parking_lot::{Condvar, Mutex},
+    std::{mem, rc::Rc, sync::Arc},
+    uapi::OwnedFd,
+};
+
+pub struct FdCloser {
+    fds: Mutex<Vec<OwnedFd>>,
+    cv: Condvar,
+}
+
+impl FdCloser {
+    pub fn new() -> Arc<Self> {
+        let slf = Arc::new(Self {
+            fds: Mutex::new(Vec::new()),
+            cv: Condvar::new(),
+        });
+        let slf2 = slf.clone();
+        std::thread::Builder::new()
+            .name("fd closer".to_string())
+            .spawn(move || {
+                let mut fds = vec![];
+                let mut lock = slf2.fds.lock();
+                loop {
+                    mem::swap(&mut *lock, &mut fds);
+                    if fds.len() > 0 {
+                        drop(lock);
+                        fds.clear();
+                        lock = slf2.fds.lock();
+                    } else {
+                        slf2.cv.wait(&mut lock);
+                    }
+                }
+            })
+            .unwrap();
+        slf
+    }
+
+    pub fn close(&self, fd: Rc<OwnedFd>) {
+        match Rc::try_unwrap(fd) {
+            Ok(fd) => {
+                self.fds.lock().push(fd);
+                self.cv.notify_all();
+            }
+            Err(_e) => {
+                log::warn!(
+                    "Could not close file descriptor in separate thread. There are still references."
+                );
+            }
+        }
+    }
+}
--- a/crates/utils/src/free_list.rs
+++ b/crates/utils/src/free_list.rs
@ -0,0 +1,93 @@
+#[cfg(test)]
+mod tests;
+
+use {
+    crate::ptr_ext::MutPtrExt,
+    std::{
+        array,
+        cell::UnsafeCell,
+        fmt::{Debug, Formatter},
+        marker::PhantomData,
+    },
+};
+
+type Seg = usize;
+const SEG_SIZE: usize = size_of::<Seg>() * 8;
+
+pub struct FreeList<T, const N: usize> {
+    levels: UnsafeCell<[Vec<Seg>; N]>,
+    _phantom: PhantomData<T>,
+}
+
+impl<T, const N: usize> Default for FreeList<T, N> {
+    fn default() -> Self {
+        Self {
+            levels: UnsafeCell::new(array::from_fn(|_| Vec::new())),
+            _phantom: Default::default(),
+        }
+    }
+}
+
+impl<T, const N: usize> Debug for FreeList<T, N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("FreeList")
+            .field("levels", self.get())
+            .finish()
+    }
+}
+
+impl<T, const N: usize> FreeList<T, N> {
+    fn get(&self) -> &mut [Vec<Seg>; N] {
+        unsafe { self.levels.get().deref_mut() }
+    }
+
+    pub fn release(&self, n: T)
+    where
+        T: Into<u32>,
+    {
+        let mut ext = n.into() as usize;
+        let mut int;
+        let levels = self.get();
+        assert!(ext / SEG_SIZE < levels[0].len());
+        for level in self.get() {
+            int = ext % SEG_SIZE;
+            ext /= SEG_SIZE;
+            unsafe {
+                *level.get_unchecked_mut(ext) |= 1 << int;
+            }
+        }
+    }
+
+    pub fn acquire(&self) -> T
+    where
+        u32: Into<T>,
+    {
+        let mut ext = 'last: {
+            let level = &mut self.get()[N - 1];
+            for (idx, &seg) in level.iter().enumerate() {
+                if seg != 0 {
+                    break 'last idx;
+                }
+            }
+            level.len()
+        };
+        for level in self.get().iter_mut().rev() {
+            if ext == level.len() {
+                level.push(!0);
+            }
+            let seg = unsafe { level.get_unchecked(ext) };
+            ext = SEG_SIZE * ext + seg.trailing_zeros() as usize;
+        }
+        let id = ext as u32;
+        for level in self.get().iter_mut() {
+            let int = ext % SEG_SIZE;
+            ext /= SEG_SIZE;
+            let seg = unsafe { level.get_unchecked_mut(ext) };
+            *seg &= !(1 << int);
+            if *seg != 0 {
+                break;
+            }
+        }
+        id.into()
+    }
+}
--- a/crates/utils/src/free_list/tests.rs
+++ b/crates/utils/src/free_list/tests.rs
@ -0,0 +1,40 @@
+use crate::free_list::FreeList;
+
+#[test]
+fn test() {
+    let list = FreeList::<u32, 3>::default();
+    for i in 0..4097 {
+        assert_eq!(list.acquire(), i);
+    }
+    list.release(100);
+    assert_eq!(list.acquire(), 100);
+    assert_eq!(list.acquire(), 4097);
+    for i in 1..22 {
+        list.release(i);
+    }
+    for i in 1..22 {
+        assert_eq!(list.acquire(), i);
+    }
+    assert_eq!(list.acquire(), 4098);
+    for i in 64..128 {
+        list.release(i);
+    }
+    for i in 64..128 {
+        assert_eq!(list.acquire(), i);
+    }
+    assert_eq!(list.acquire(), 4099);
+    for i in 0..4100 {
+        list.release(i);
+    }
+    for i in 0..4101 {
+        assert_eq!(list.acquire(), i);
+    }
+}
+
+#[test]
+#[should_panic]
+fn release_out_of_bounds() {
+    let list = FreeList::<u32, 3>::default();
+    list.acquire();
+    list.release(500);
+}
--- a/crates/utils/src/geometric_decay.rs
+++ b/crates/utils/src/geometric_decay.rs
@ -0,0 +1,37 @@
+use std::cell::Cell;
+
+pub struct GeometricDecay {
+    p1: f64,
+    p2: f64,
+    v: Cell<f64>,
+}
+
+impl GeometricDecay {
+    pub fn new(mut p1: f64, reset: u64) -> Self {
+        if p1.is_nan() || p1 < 0.01 {
+            p1 = 0.01;
+        }
+        if p1 > 0.99 {
+            p1 = 0.99;
+        }
+        let p2 = 1.0 - p1;
+        Self {
+            p1,
+            p2,
+            v: Cell::new(reset as f64 / p1),
+        }
+    }
+
+    pub fn reset(&self, v: u64) {
+        self.v.set(v as f64 / self.p1);
+    }
+
+    pub fn get(&self) -> u64 {
+        (self.p1 * self.v.get()) as u64
+    }
+
+    pub fn add(&self, n: u64) {
+        let v = n as f64 + self.p2 * self.v.get();
+        self.v.set(v);
+    }
+}
--- a/crates/utils/src/hash_map_ext.rs
+++ b/crates/utils/src/hash_map_ext.rs
@ -0,0 +1,15 @@
+use std::collections::HashMap;
+
+pub trait HashMapExt {
+    type V;
+
+    fn drain_values(&mut self) -> impl Iterator<Item = Self::V>;
+}
+
+impl<K, V, S> HashMapExt for HashMap<K, V, S> {
+    type V = V;
+
+    fn drain_values(&mut self) -> impl Iterator<Item = Self::V> {
+        self.drain().map(|(_, v)| v)
+    }
+}
--- a/crates/utils/src/lib.rs
+++ b/crates/utils/src/lib.rs
@ -0,0 +1,58 @@
+pub mod array;
+pub mod array_to_tuple;
+pub mod asyncevent;
+pub mod atomic_enum;
+pub mod binary_search_map;
+pub mod bitfield;
+pub mod bitflags;
+pub mod buf;
+pub mod cell_ext;
+pub mod clonecell;
+pub mod compat;
+pub mod copyhashmap;
+pub mod double_buffered;
+pub mod errorfmt;
+pub mod event_listener;
+pub mod fdcloser;
+pub mod free_list;
+pub mod geometric_decay;
+pub mod hash_map_ext;
+pub mod linkedlist;
+pub mod log_on_drop;
+pub mod mmap;
+pub mod nice;
+pub mod nonblock;
+pub mod num_cpus;
+pub mod numcell;
+pub mod on_change;
+pub mod on_drop_event;
+pub mod once;
+pub mod opaque;
+pub mod opaque_cell;
+pub mod opt;
+pub mod option_ext;
+pub mod ordered_float;
+pub mod oserror;
+pub mod page_size;
+pub mod pid_info;
+pub mod pidfd_send_signal;
+pub mod pipe;
+pub mod process_name;
+pub mod ptr_ext;
+pub mod queue;
+pub mod rc_eq;
+pub mod refcounted;
+pub mod smallmap;
+pub mod stack;
+pub mod static_text;
+pub mod string_ext;
+pub mod syncqueue;
+pub mod threshold_counter;
+pub mod tri;
+pub mod unlink_on_drop;
+pub mod vec_ext;
+pub mod vecdeque_ext;
+pub mod vecset;
+pub mod vecstorage;
+pub mod windows;
+pub mod xrd;
--- a/crates/utils/src/linkedlist.rs
+++ b/crates/utils/src/linkedlist.rs
@ -0,0 +1,414 @@
+use {
+    crate::numcell::NumCell,
+    std::{
+        cell::Cell,
+        fmt::{Debug, Formatter},
+        mem,
+        ops::Deref,
+        ptr::NonNull,
+    },
+};
+
+const LINKED_NODE_REF_COUNT: usize = !(!0 >> 1);
+
+pub struct LinkedList<T> {
+    root: LinkedNode<T>,
+}
+
+impl<T: Debug> Debug for LinkedList<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_list().entries(self.iter()).finish()
+    }
+}
+
+impl<T> Default for LinkedList<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T> LinkedList<T> {
+    pub fn new() -> Self {
+        Self {
+            root: LinkedNode::new(None),
+        }
+    }
+
+    pub fn append_all(&self, other: &LinkedList<T>) {
+        if other.is_empty() || self.root.data == other.root.data {
+            return;
+        }
+        unsafe {
+            let o_root = other.root.data;
+            let o_first = o_root.as_ref().next.get();
+            let o_last = o_root.as_ref().prev.get();
+            let s_first = self.root.data;
+            let s_last = s_first.as_ref().prev.get();
+            o_first.as_ref().prev.set(s_last);
+            s_last.as_ref().next.set(o_first);
+            o_last.as_ref().next.set(s_first);
+            s_first.as_ref().prev.set(o_last);
+            o_root.as_ref().next.set(o_root);
+            o_root.as_ref().prev.set(o_root);
+        }
+    }
+
+    fn endpoint(&self, ep: NonNull<NodeData<T>>) -> Option<NodeRef<T>> {
+        unsafe {
+            if ep != self.root.data {
+                ep.as_ref().rc.fetch_add(1);
+                Some(NodeRef { data: ep })
+            } else {
+                None
+            }
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.last().is_none()
+    }
+
+    pub fn is_not_empty(&self) -> bool {
+        !self.is_empty()
+    }
+
+    pub fn last(&self) -> Option<NodeRef<T>> {
+        unsafe { self.endpoint(self.root.data.as_ref().prev.get()) }
+    }
+
+    pub fn first(&self) -> Option<NodeRef<T>> {
+        unsafe { self.endpoint(self.root.data.as_ref().next.get()) }
+    }
+
+    pub fn add_last(&self, t: T) -> LinkedNode<T> {
+        self.root.prepend(t)
+    }
+
+    pub fn add_first(&self, t: T) -> LinkedNode<T> {
+        self.root.append(t)
+    }
+
+    pub fn add_last_existing(&self, t: &NodeRef<T>) {
+        self.root.prepend_existing(t)
+    }
+
+    pub fn add_first_existing(&self, t: &NodeRef<T>) {
+        self.root.append_existing(t)
+    }
+
+    pub fn rotate_last(&self, t: &NodeRef<T>) {
+        unsafe {
+            let root = self.root.data.as_ref();
+            root.prev.get().as_ref().next.set(root.next.get());
+            root.next.get().as_ref().prev.set(root.prev.get());
+            root.prev.set(t.data);
+            root.next.set(t.data.as_ref().next.get());
+            t.data.as_ref().next.get().as_ref().prev.set(self.root.data);
+            t.data.as_ref().next.set(self.root.data);
+        }
+    }
+
+    pub fn iter(&self) -> LinkedListIter<T> {
+        unsafe {
+            let root = self.root.data.as_ref();
+            root.rc.fetch_add(1);
+            root.next.get().as_ref().rc.fetch_add(1);
+            LinkedListIter {
+                root: self.root.data,
+                next: root.next.get(),
+            }
+        }
+    }
+
+    pub fn rev_iter(&self) -> RevLinkedListIter<T> {
+        unsafe {
+            let root = self.root.data.as_ref();
+            root.rc.fetch_add(1);
+            root.prev.get().as_ref().rc.fetch_add(1);
+            RevLinkedListIter {
+                root: self.root.data,
+                next: root.prev.get(),
+            }
+        }
+    }
+}
+
+pub struct LinkedListIter<T> {
+    root: NonNull<NodeData<T>>,
+    next: NonNull<NodeData<T>>,
+}
+
+impl<T> Iterator for LinkedListIter<T> {
+    type Item = NodeRef<T>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.root == self.next {
+            return None;
+        }
+        unsafe {
+            let old_next = self.next;
+            self.next = old_next.as_ref().next.get();
+            self.next.as_ref().rc.fetch_add(1);
+            Some(NodeRef { data: old_next })
+        }
+    }
+}
+
+impl<T> Drop for LinkedListIter<T> {
+    fn drop(&mut self) {
+        unsafe {
+            dec_ref_count(self.root, 1);
+            dec_ref_count(self.next, 1);
+        }
+    }
+}
+
+pub struct RevLinkedListIter<T> {
+    root: NonNull<NodeData<T>>,
+    next: NonNull<NodeData<T>>,
+}
+
+impl<T> Iterator for RevLinkedListIter<T> {
+    type Item = NodeRef<T>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.root == self.next {
+            return None;
+        }
+        unsafe {
+            let old_next = self.next;
+            self.next = old_next.as_ref().prev.get();
+            self.next.as_ref().rc.fetch_add(1);
+            Some(NodeRef { data: old_next })
+        }
+    }
+}
+
+impl<T> Drop for RevLinkedListIter<T> {
+    fn drop(&mut self) {
+        unsafe {
+            dec_ref_count(self.root, 1);
+            dec_ref_count(self.next, 1);
+        }
+    }
+}
+
+#[repr(transparent)]
+#[must_use]
+pub struct LinkedNode<T> {
+    data: NonNull<NodeData<T>>,
+}
+
+impl<T: Debug> Debug for LinkedNode<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        unsafe { self.data.as_ref().data.as_ref().unwrap_unchecked().fmt(f) }
+    }
+}
+
+impl<T> Deref for LinkedNode<T> {
+    type Target = NodeRef<T>;
+
+    fn deref(&self) -> &Self::Target {
+        unsafe { mem::transmute(self) }
+    }
+}
+
+#[repr(transparent)]
+pub struct NodeRef<T> {
+    data: NonNull<NodeData<T>>,
+}
+
+impl<T: Debug> Debug for NodeRef<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        unsafe { self.data.as_ref().data.as_ref().unwrap_unchecked().fmt(f) }
+    }
+}
+
+impl<T> Deref for NodeRef<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        unsafe { self.data.as_ref().data.as_ref().unwrap_unchecked() }
+    }
+}
+
+impl<T> Drop for NodeRef<T> {
+    fn drop(&mut self) {
+        unsafe {
+            dec_ref_count(self.data, 1);
+        }
+    }
+}
+
+impl<T> Clone for NodeRef<T> {
+    fn clone(&self) -> Self {
+        unsafe {
+            self.data.as_ref().rc.fetch_add(1);
+            Self { data: self.data }
+        }
+    }
+}
+
+impl<T> NodeRef<T> {
+    pub fn prepend(&self, t: T) -> LinkedNode<T> {
+        unsafe { prepend(self.data, t) }
+    }
+
+    pub fn append(&self, t: T) -> LinkedNode<T> {
+        unsafe { append(self.data, t) }
+    }
+
+    pub fn prepend_existing(&self, t: &NodeRef<T>) {
+        unsafe { prepend_existing(self.data, t) }
+    }
+
+    pub fn append_existing(&self, t: &NodeRef<T>) {
+        unsafe { append_existing(self.data, t) }
+    }
+
+    fn peer<F>(&self, peer: F) -> Option<NodeRef<T>>
+    where
+        F: FnOnce(&NodeData<T>) -> &Cell<NonNull<NodeData<T>>>,
+    {
+        unsafe {
+            let data = self.data.as_ref();
+            let other = peer(data).get();
+            if other.as_ref().data.is_some() {
+                other.as_ref().rc.fetch_add(1);
+                Some(NodeRef { data: other })
+            } else {
+                None
+            }
+        }
+    }
+
+    pub fn prev(&self) -> Option<NodeRef<T>> {
+        self.peer(|d| &d.prev)
+    }
+
+    pub fn next(&self) -> Option<NodeRef<T>> {
+        self.peer(|d| &d.next)
+    }
+
+    pub fn detach(&self) {
+        unsafe {
+            let data = self.data.as_ref();
+            data.prev.get().as_ref().next.set(data.next.get());
+            data.next.get().as_ref().prev.set(data.prev.get());
+            data.prev.set(self.data);
+            data.next.set(self.data);
+        }
+    }
+}
+
+struct NodeData<T> {
+    rc: NumCell<usize>,
+    prev: Cell<NonNull<NodeData<T>>>,
+    next: Cell<NonNull<NodeData<T>>>,
+    data: Option<T>,
+}
+
+unsafe fn dec_ref_count<T>(slf: NonNull<NodeData<T>>, n: usize) {
+    unsafe {
+        if slf.as_ref().rc.fetch_sub(n) == n {
+            drop(Box::from_raw(slf.as_ptr()));
+        }
+    }
+}
+
+impl<T> Drop for LinkedNode<T> {
+    fn drop(&mut self) {
+        unsafe {
+            self.detach();
+            dec_ref_count(self.data, LINKED_NODE_REF_COUNT);
+        }
+    }
+}
+
+impl<T> LinkedNode<T> {
+    fn new(t: Option<T>) -> Self {
+        let node = Box::leak(Box::new(NodeData {
+            rc: NumCell::new(LINKED_NODE_REF_COUNT),
+            prev: Cell::new(NonNull::dangling()),
+            next: Cell::new(NonNull::dangling()),
+            data: t,
+        }));
+        let ptr = NonNull::from(&mut *node);
+        node.prev.set(ptr);
+        node.next.set(ptr);
+        LinkedNode { data: node.into() }
+    }
+
+    pub fn detached(t: T) -> Self {
+        Self::new(Some(t))
+    }
+
+    pub fn to_ref(&self) -> NodeRef<T> {
+        unsafe {
+            self.data.as_ref().rc.fetch_add(1);
+            NodeRef { data: self.data }
+        }
+    }
+}
+
+unsafe fn prepend_existing<T>(data: NonNull<NodeData<T>>, t: &NodeRef<T>) {
+    unsafe {
+        let dref = data.as_ref();
+        let tref = t.data.as_ref();
+        if tref.rc.get() < LINKED_NODE_REF_COUNT {
+            log::error!("Trying to prepend a node whose linked node has already been dropped");
+            return;
+        }
+        t.detach();
+        tref.prev.set(dref.prev.get());
+        tref.next.set(data);
+        dref.prev.get().as_ref().next.set(t.data);
+        dref.prev.set(t.data);
+    }
+}
+
+unsafe fn prepend<T>(data: NonNull<NodeData<T>>, t: T) -> LinkedNode<T> {
+    unsafe {
+        let dref = data.as_ref();
+        let node = NonNull::new_unchecked(Box::into_raw(Box::new(NodeData {
+            rc: NumCell::new(LINKED_NODE_REF_COUNT),
+            prev: Cell::new(dref.prev.get()),
+            next: Cell::new(data),
+            data: Some(t),
+        })));
+        dref.prev.get().as_ref().next.set(node);
+        dref.prev.set(node);
+        LinkedNode { data: node }
+    }
+}
+
+unsafe fn append_existing<T>(data: NonNull<NodeData<T>>, t: &NodeRef<T>) {
+    unsafe {
+        let dref = data.as_ref();
+        let tref = t.data.as_ref();
+        if tref.rc.get() < LINKED_NODE_REF_COUNT {
+            log::error!("Trying to append a node whose linked node has already been dropped");
+            return;
+        }
+        t.detach();
+        tref.prev.set(data);
+        tref.next.set(dref.next.get());
+        dref.next.get().as_ref().prev.set(t.data);
+        dref.next.set(t.data);
+    }
+}
+
+unsafe fn append<T>(data: NonNull<NodeData<T>>, t: T) -> LinkedNode<T> {
+    unsafe {
+        let dref = data.as_ref();
+        let node = NonNull::new_unchecked(Box::into_raw(Box::new(NodeData {
+            rc: NumCell::new(LINKED_NODE_REF_COUNT),
+            prev: Cell::new(data),
+            next: Cell::new(dref.next.get()),
+            data: Some(t),
+        })));
+        dref.next.get().as_ref().prev.set(node);
+        dref.next.set(node);
+        LinkedNode { data: node }
+    }
+}
--- a/crates/utils/src/log_on_drop.rs
+++ b/crates/utils/src/log_on_drop.rs
@ -0,0 +1,7 @@
+pub struct LogOnDrop(pub &'static str);
+
+impl Drop for LogOnDrop {
+    fn drop(&mut self) {
+        log::info!("{}", self.0);
+    }
+}
--- a/crates/utils/src/mmap.rs
+++ b/crates/utils/src/mmap.rs
@ -0,0 +1,34 @@
+use {
+    crate::{oserror::OsError, ptr_ext::PtrExt},
+    std::ptr,
+    uapi::c,
+};
+
+pub struct Mmapped {
+    pub ptr: *const [u8],
+}
+
+pub fn mmap(
+    len: usize,
+    prot: c::c_int,
+    flags: c::c_int,
+    fd: c::c_int,
+    offset: c::off_t,
+) -> Result<Mmapped, OsError> {
+    let res = unsafe { c::mmap(ptr::null_mut(), len, prot, flags, fd, offset) };
+    if res == c::MAP_FAILED {
+        Err(OsError::default())
+    } else {
+        Ok(Mmapped {
+            ptr: ptr::slice_from_raw_parts(res.cast(), len),
+        })
+    }
+}
+
+impl Drop for Mmapped {
+    fn drop(&mut self) {
+        unsafe {
+            c::munmap(self.ptr.deref().as_ptr() as _, self.ptr.deref().len());
+        }
+    }
+}
--- a/crates/utils/src/nice.rs
+++ b/crates/utils/src/nice.rs
@ -0,0 +1,28 @@
+use {
+    c::sched_setscheduler,
+    std::{
+        env, mem,
+        sync::atomic::{AtomicBool, Ordering::Relaxed},
+    },
+    uapi::c::{self, SCHED_RESET_ON_FORK, SCHED_RR, sched_param},
+};
+
+static DID_ELEVATE_SCHEDULER: AtomicBool = AtomicBool::new(false);
+
+pub const JAY_NO_REALTIME: &str = "JAY_NO_REALTIME";
+
+pub fn elevate_scheduler() {
+    if env::var(JAY_NO_REALTIME).as_deref().unwrap_or_default() == "1" {
+        return;
+    }
+    let mut param = unsafe { mem::zeroed::<sched_param>() };
+    param.sched_priority = 1;
+    let res = unsafe { sched_setscheduler(0, SCHED_RR | SCHED_RESET_ON_FORK, &param) };
+    if res == 0 {
+        DID_ELEVATE_SCHEDULER.store(true, Relaxed);
+    }
+}
+
+pub fn did_elevate_scheduler() -> bool {
+    DID_ELEVATE_SCHEDULER.load(Relaxed)
+}
--- a/crates/utils/src/nonblock.rs
+++ b/crates/utils/src/nonblock.rs
@ -0,0 +1,16 @@
+use {
+    crate::oserror::{OsError, OsErrorExt},
+    uapi::c,
+};
+
+pub fn set_nonblock(fd: c::c_int) -> Result<(), OsError> {
+    let fl = uapi::fcntl_getfl(fd).to_os_error()?;
+    uapi::fcntl_setfl(fd, fl | c::O_NONBLOCK).to_os_error()?;
+    Ok(())
+}
+
+pub fn set_block(fd: c::c_int) -> Result<(), OsError> {
+    let fl = uapi::fcntl_getfl(fd).to_os_error()?;
+    uapi::fcntl_setfl(fd, fl & !c::O_NONBLOCK).to_os_error()?;
+    Ok(())
+}
--- a/crates/utils/src/num_cpus.rs
+++ b/crates/utils/src/num_cpus.rs
@ -0,0 +1,20 @@
+use {
+    crate::oserror::{OsError, OsErrorExt},
+    smallvec::{SmallVec, smallvec_inline},
+    uapi::c,
+};
+
+pub fn num_cpus() -> Result<u32, OsError> {
+    let mut buf: SmallVec<[usize; 32]> = smallvec_inline![0; 32];
+    loop {
+        match uapi::sched_getaffinity(0, &mut buf).to_os_error() {
+            Ok(_) => return Ok(count(&buf)),
+            Err(OsError(c::EINVAL)) => buf.extend_from_slice(&[0; 32][..]),
+            Err(e) => return Err(e),
+        }
+    }
+}
+
+fn count(buf: &[usize]) -> u32 {
+    buf.iter().copied().map(|n| n.count_ones()).sum()
+}
--- a/crates/utils/src/numcell.rs
+++ b/crates/utils/src/numcell.rs
@ -0,0 +1,129 @@
+use std::{
+    cell::Cell,
+    fmt::{Debug, Formatter},
+    ops::{Add, BitAnd, BitOr, Sub},
+};
+
+#[derive(Default)]
+pub struct NumCell<T> {
+    t: Cell<T>,
+}
+
+impl<T: Copy + Debug> Debug for NumCell<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.t.get().fmt(f)
+    }
+}
+
+impl<T> NumCell<T> {
+    #[inline(always)]
+    pub fn new(t: T) -> Self {
+        Self { t: Cell::new(t) }
+    }
+
+    #[inline(always)]
+    pub fn set(&self, n: T) {
+        let _ = self.t.replace(n);
+    }
+
+    #[inline(always)]
+    pub fn replace(&self, n: T) -> T {
+        self.t.replace(n)
+    }
+
+    #[inline(always)]
+    pub fn get(&self) -> T
+    where
+        T: Copy,
+    {
+        self.t.get()
+    }
+
+    #[inline(always)]
+    pub fn fetch_add(&self, n: T) -> T
+    where
+        T: Copy + Add<T, Output = T>,
+    {
+        let res = self.t.get();
+        self.t.set(res + n);
+        res
+    }
+
+    #[inline(always)]
+    pub fn add_fetch(&self, n: T) -> T
+    where
+        T: Copy + Add<T, Output = T>,
+    {
+        let res = self.t.get() + n;
+        self.t.set(res);
+        res
+    }
+
+    #[inline(always)]
+    pub fn fetch_sub(&self, n: T) -> T
+    where
+        T: Copy + Sub<T, Output = T>,
+    {
+        let res = self.t.get();
+        self.t.set(res - n);
+        res
+    }
+
+    #[inline(always)]
+    pub fn or_assign(&self, n: T)
+    where
+        T: Copy + BitOr<Output = T>,
+    {
+        self.t.set(self.t.get() | n);
+    }
+
+    #[inline(always)]
+    pub fn and_assign(&self, n: T)
+    where
+        T: Copy + BitAnd<Output = T>,
+    {
+        self.t.set(self.t.get() & n);
+    }
+
+    #[inline(always)]
+    pub fn is_zero(&self) -> bool
+    where
+        T: Eq + Copy + Default,
+    {
+        self.t.get() == T::default()
+    }
+
+    #[inline(always)]
+    pub fn is_not_zero(&self) -> bool
+    where
+        T: Eq + Copy + Default,
+    {
+        !self.is_zero()
+    }
+
+    #[inline(always)]
+    pub fn take(&self) -> T
+    where
+        T: Default,
+    {
+        self.t.replace(T::default())
+    }
+}
+
+impl<T: BitOr<Output = T> + Copy> BitOr<T> for &'_ NumCell<T> {
+    type Output = T;
+
+    #[inline(always)]
+    fn bitor(self, rhs: T) -> Self::Output {
+        self.t.get() | rhs
+    }
+}
+
+impl<T: BitAnd<Output = T> + Copy> BitAnd<T> for &'_ NumCell<T> {
+    type Output = T;
+
+    #[inline(always)]
+    fn bitand(self, rhs: T) -> Self::Output {
+        self.t.get() & rhs
+    }
+}
--- a/crates/utils/src/on_change.rs
+++ b/crates/utils/src/on_change.rs
@ -0,0 +1,44 @@
+use {
+    crate::{clonecell::CloneCell, syncqueue::SyncQueue},
+    std::{
+        fmt::{Debug, Formatter},
+        rc::Rc,
+    },
+};
+
+pub struct OnChange<T> {
+    pub on_change: CloneCell<Option<Rc<dyn Fn()>>>,
+    pub events: SyncQueue<T>,
+}
+
+impl<T> OnChange<T> {
+    pub fn clear(&self) {
+        self.on_change.take();
+        self.events.take();
+    }
+
+    pub fn send_event(&self, event: T) {
+        self.events.push(event);
+        if let Some(cb) = self.on_change.get() {
+            cb();
+        }
+    }
+}
+
+impl<T> Default for OnChange<T> {
+    fn default() -> Self {
+        Self {
+            on_change: Default::default(),
+            events: Default::default(),
+        }
+    }
+}
+
+impl<T> Debug for OnChange<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self.on_change.get() {
+            None => f.write_str("None"),
+            Some(_) => f.write_str("Some"),
+        }
+    }
+}
--- a/crates/utils/src/on_drop_event.rs
+++ b/crates/utils/src/on_drop_event.rs
@ -0,0 +1,18 @@
+use {crate::asyncevent::AsyncEvent, std::rc::Rc};
+
+#[derive(Default)]
+pub struct OnDropEvent {
+    ae: Rc<AsyncEvent>,
+}
+
+impl OnDropEvent {
+    pub fn event(&self) -> Rc<AsyncEvent> {
+        self.ae.clone()
+    }
+}
+
+impl Drop for OnDropEvent {
+    fn drop(&mut self) {
+        self.ae.trigger()
+    }
+}
--- a/crates/utils/src/once.rs
+++ b/crates/utils/src/once.rs
@ -0,0 +1,26 @@
+#![allow(dead_code)]
+
+use std::{cell::Cell, future::Future};
+
+#[derive(Default)]
+pub struct Once {
+    done: Cell<bool>,
+}
+
+impl Once {
+    pub fn set(&self) -> bool {
+        !self.done.replace(true)
+    }
+
+    pub fn exec<F: FnOnce()>(&self, f: F) {
+        if !self.done.replace(true) {
+            f();
+        }
+    }
+
+    pub async fn exec_async<G: Future<Output = ()>, F: FnOnce() -> G>(&self, f: F) {
+        if !self.done.replace(true) {
+            f().await;
+        }
+    }
+}
--- a/crates/utils/src/opaque.rs
+++ b/crates/utils/src/opaque.rs
@ -0,0 +1,109 @@
+use {
+    crate::array,
+    arrayvec::ArrayString,
+    rand::{RngExt, rng},
+    serde::{Deserialize, Deserializer, Serialize, Serializer, de},
+    std::{
+        fmt::{Debug, Display, Formatter},
+        num::ParseIntError,
+        str::FromStr,
+    },
+    thiserror::Error,
+};
+
+#[cfg(test)]
+mod tests;
+
+#[derive(Copy, Clone, Eq, PartialEq, Hash, Ord, PartialOrd)]
+#[repr(transparent)]
+pub struct Opaque {
+    v: [u64; 3],
+}
+
+pub fn opaque() -> Opaque {
+    let mut rng = rng();
+    Opaque {
+        v: array::from_fn(|_| rng.random()),
+    }
+}
+
+impl Opaque {
+    pub fn to_string(self) -> ArrayString<OPAQUE_LEN> {
+        use std::fmt::Write;
+        let mut s = ArrayString::new();
+        write!(s, "{}", self).unwrap();
+        s
+    }
+}
+
+impl Display for Opaque {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{:016x}", self.v[2])?;
+        write!(f, "{:016x}", self.v[1])?;
+        write!(f, "{:016x}", self.v[0])?;
+        Ok(())
+    }
+}
+
+impl Debug for Opaque {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        Display::fmt(self, f)
+    }
+}
+
+impl Serialize for Opaque {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let s = self.to_string();
+        serializer.serialize_str(&s)
+    }
+}
+
+impl<'de> Deserialize<'de> for Opaque {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = <&str>::deserialize(deserializer)?;
+        Opaque::from_str(s).map_err(de::Error::custom)
+    }
+}
+
+impl FromStr for Opaque {
+    type Err = OpaqueError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.len() != OPAQUE_LEN {
+            return Err(OpaqueError::InvalidStringLength);
+        }
+        if !s.is_char_boundary(OPAQUE_SEGMENT) {
+            return Err(OpaqueError::NotAscii);
+        }
+        let (a, s) = s.split_at(OPAQUE_SEGMENT);
+        if !s.is_char_boundary(OPAQUE_SEGMENT) {
+            return Err(OpaqueError::NotAscii);
+        }
+        let (b, c) = s.split_at(OPAQUE_SEGMENT);
+        let v = [
+            u64::from_str_radix(c, 16).map_err(OpaqueError::Parse)?,
+            u64::from_str_radix(b, 16).map_err(OpaqueError::Parse)?,
+            u64::from_str_radix(a, 16).map_err(OpaqueError::Parse)?,
+        ];
+        Ok(Self { v })
+    }
+}
+
+pub const OPAQUE_LEN: usize = 48;
+const OPAQUE_SEGMENT: usize = OPAQUE_LEN / 3;
+
+#[derive(Debug, Error)]
+pub enum OpaqueError {
+    #[error("The string is not exactly {OPAQUE_LEN} bytes long")]
+    InvalidStringLength,
+    #[error("The string is not ascii")]
+    NotAscii,
+    #[error("Could not parse the string as a hex number")]
+    Parse(ParseIntError),
+}
--- a/crates/utils/src/opaque/tests.rs
+++ b/crates/utils/src/opaque/tests.rs
@ -0,0 +1,12 @@
+use {
+    crate::opaque::{Opaque, opaque},
+    std::str::FromStr,
+};
+
+#[test]
+fn roundtrip() {
+    let v1 = opaque();
+    let s = v1.to_string();
+    let v2 = Opaque::from_str(&s).unwrap();
+    assert_eq!(v1, v2);
+}
--- a/crates/utils/src/opaque_cell.rs
+++ b/crates/utils/src/opaque_cell.rs
@ -0,0 +1,28 @@
+use std::{
+    cell::Cell,
+    fmt::{Debug, Formatter},
+    ops::{Deref, DerefMut},
+};
+
+#[derive(Default)]
+pub struct OpaqueCell<T>(Cell<T>);
+
+impl<T> Deref for OpaqueCell<T> {
+    type Target = Cell<T>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<T> DerefMut for OpaqueCell<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<T> Debug for OpaqueCell<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Cell<{}> {{ ... }}", std::any::type_name::<T>())
+    }
+}
--- a/crates/utils/src/opt.rs
+++ b/crates/utils/src/opt.rs
@ -0,0 +1,27 @@
+use {crate::clonecell::CloneCell, std::rc::Rc};
+
+pub struct Opt<T> {
+    t: CloneCell<Option<Rc<T>>>,
+}
+
+impl<T> Default for Opt<T> {
+    fn default() -> Self {
+        Self {
+            t: Default::default(),
+        }
+    }
+}
+
+impl<T> Opt<T> {
+    pub fn set(&self, t: Option<Rc<T>>) {
+        self.t.set(t);
+    }
+
+    pub fn get(&self) -> Option<Rc<T>> {
+        self.t.get()
+    }
+
+    pub fn is_none(&self) -> bool {
+        self.t.is_none()
+    }
+}
--- a/crates/utils/src/option_ext.rs
+++ b/crates/utils/src/option_ext.rs
@ -0,0 +1,9 @@
+pub trait OptionExt<T> {
+    fn get_or_insert_default_ext(&mut self) -> &mut T;
+}
+
+impl<T: Default> OptionExt<T> for Option<T> {
+    fn get_or_insert_default_ext(&mut self) -> &mut T {
+        self.get_or_insert_with(|| Default::default())
+    }
+}
--- a/crates/utils/src/ordered_float.rs
+++ b/crates/utils/src/ordered_float.rs
@ -0,0 +1,74 @@
+use std::{
+    fmt::{Debug, Display, Formatter},
+    hash::{Hash, Hasher},
+    ops::{Add, Div, Mul, Sub},
+};
+
+macro_rules! define {
+    ($big:ident, $little:ty) => {
+        #[derive(Copy, Clone)]
+        #[repr(transparent)]
+        pub struct $big(pub $little);
+
+        impl Eq for $big {}
+
+        impl PartialEq for $big {
+            fn eq(&self, other: &Self) -> bool {
+                self.0.to_bits() == other.0.to_bits()
+            }
+        }
+
+        impl Hash for $big {
+            fn hash<H: Hasher>(&self, state: &mut H) {
+                self.0.to_bits().hash(state);
+            }
+        }
+
+        impl Add<Self> for $big {
+            type Output = Self;
+
+            fn add(self, rhs: $big) -> Self::Output {
+                Self(self.0 + rhs.0)
+            }
+        }
+
+        impl Sub<Self> for $big {
+            type Output = Self;
+
+            fn sub(self, rhs: Self) -> Self::Output {
+                Self(self.0 - rhs.0)
+            }
+        }
+
+        impl Mul<Self> for $big {
+            type Output = Self;
+
+            fn mul(self, rhs: Self) -> Self::Output {
+                Self(self.0 * rhs.0)
+            }
+        }
+
+        impl Div<Self> for $big {
+            type Output = Self;
+
+            fn div(self, rhs: Self) -> Self::Output {
+                Self(self.0 / rhs.0)
+            }
+        }
+
+        impl Display for $big {
+            fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+                Display::fmt(&self.0, f)
+            }
+        }
+
+        impl Debug for $big {
+            fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+                Debug::fmt(&self.0, f)
+            }
+        }
+    };
+}
+
+define!(F64, f64);
+define!(F32, f32);
--- a/crates/utils/src/oserror.rs
+++ b/crates/utils/src/oserror.rs
@ -0,0 +1,242 @@
+use {
+    std::{
+        error::Error,
+        fmt::{Display, Formatter},
+        sync::LazyLock,
+    },
+    uapi::{
+        Errno,
+        c::{self, c_int},
+    },
+};
+
+static ERRORS: LazyLock<&'static [Option<&'static str>]> = LazyLock::new(|| {
+    static MSGS: &[(c::c_int, &str)] = &[
+        (c::EWOULDBLOCK, "Operation would block"),
+        (c::ENOTSUP, "Not supported"),
+        (c::EHWPOISON, "Memory page has hardware error"),
+        (c::ERFKILL, "Operation not possible due to RF-kill"),
+        (c::EKEYREJECTED, "Key was rejected by service"),
+        (c::EKEYREVOKED, "Key has been revoked"),
+        (c::EKEYEXPIRED, "Key has expired"),
+        (c::ENOKEY, "Required key not available"),
+        (c::EMEDIUMTYPE, "Wrong medium type"),
+        (c::ENOMEDIUM, "No medium found"),
+        (c::EREMOTEIO, "Remote I/O error"),
+        (c::EISNAM, "Is a named type file"),
+        (c::ENAVAIL, "No XENIX semaphores available"),
+        (c::ENOTNAM, "Not a XENIX named type file"),
+        (c::EUCLEAN, "Structure needs cleaning"),
+        (c::ESTRPIPE, "Streams pipe error"),
+        (c::ELIBEXEC, "Cannot exec a shared library directly"),
+        (
+            c::ELIBMAX,
+            "Attempting to link in too many shared libraries",
+        ),
+        (c::ELIBSCN, ".lib section in a.out corrupted"),
+        (c::ELIBBAD, "Accessing a corrupted shared library"),
+        (c::ELIBACC, "Can not access a needed shared library"),
+        (c::EREMCHG, "Remote address changed"),
+        (c::EBADFD, "File descriptor in bad state"),
+        (c::ENOTUNIQ, "Name not unique on network"),
+        (c::EDOTDOT, "RFS specific error"),
+        (c::ECOMM, "Communication error on send"),
+        (c::ESRMNT, "Srmount error"),
+        (c::EADV, "Advertise error"),
+        (c::ENOPKG, "Package not installed"),
+        (c::ENONET, "Machine is not on the network"),
+        (c::EBFONT, "Bad font file format"),
+        (c::EBADSLT, "Invalid slot"),
+        (c::EBADRQC, "Invalid request code"),
+        (c::ENOANO, "No anode"),
+        (c::EXFULL, "Exchange full"),
+        (c::EBADR, "Invalid request descriptor"),
+        (c::EBADE, "Invalid exchange"),
+        (c::EL2HLT, "Level 2 halted"),
+        (c::ENOCSI, "No CSI structure available"),
+        (c::EUNATCH, "Protocol driver not attached"),
+        (c::ELNRNG, "Link number out of range"),
+        (c::EL3RST, "Level 3 reset"),
+        (c::EL3HLT, "Level 3 halted"),
+        (c::EL2NSYNC, "Level 2 not synchronized"),
+        (c::ECHRNG, "Channel number out of range"),
+        (c::ERESTART, "Interrupted system call should be restarted"),
+        (c::ENOTRECOVERABLE, "State not recoverable"),
+        (c::EOWNERDEAD, "Owner died"),
+        (c::ECANCELED, "Operation canceled"),
+        (c::ETIME, "Timer expired"),
+        (c::EPROTO, "Protocol error"),
+        (c::EOVERFLOW, "Value too large for defined data type"),
+        (c::ENOSTR, "Device not a stream"),
+        (c::ENOSR, "Out of streams resources"),
+        (c::ENOMSG, "No message of desired type"),
+        (c::ENOLINK, "Link has been severed"),
+        (c::ENODATA, "No data available"),
+        (c::EMULTIHOP, "Multihop attempted"),
+        (c::EIDRM, "Identifier removed"),
+        (c::EBADMSG, "Bad message"),
+        (
+            c::EILSEQ,
+            "Invalid or incomplete multibyte or wide character",
+        ),
+        (c::ENOSYS, "Function not implemented"),
+        (c::ENOLCK, "No locks available"),
+        (c::EREMOTE, "Object is remote"),
+        (c::ESTALE, "Stale file handle"),
+        (c::EDQUOT, "Disk quota exceeded"),
+        (c::EUSERS, "Too many users"),
+        (c::ENOTEMPTY, "Directory not empty"),
+        (c::EHOSTUNREACH, "No route to host"),
+        (c::EHOSTDOWN, "Host is down"),
+        (c::ENAMETOOLONG, "File name too long"),
+        (c::ELOOP, "Too many levels of symbolic links"),
+        (c::ECONNREFUSED, "Connection refused"),
+        (c::ETIMEDOUT, "Connection timed out"),
+        (c::ETOOMANYREFS, "Too many references: cannot splice"),
+        (
+            c::ESHUTDOWN,
+            "Cannot send after transport endpoint shutdown",
+        ),
+        (c::EDESTADDRREQ, "Destination address required"),
+        (c::ENOTCONN, "Transport endpoint is not connected"),
+        (c::EISCONN, "Transport endpoint is already connected"),
+        (c::ENOBUFS, "No buffer space available"),
+        (c::ECONNRESET, "Connection reset by peer"),
+        (c::ECONNABORTED, "Software caused connection abort"),
+        (c::ENETRESET, "Network dropped connection on reset"),
+        (c::ENETUNREACH, "Network is unreachable"),
+        (c::ENETDOWN, "Network is down"),
+        (c::EADDRNOTAVAIL, "Cannot assign requested address"),
+        (c::EADDRINUSE, "Address already in use"),
+        (c::EAFNOSUPPORT, "Address family not supported by protocol"),
+        (c::EPFNOSUPPORT, "Protocol family not supported"),
+        (c::EOPNOTSUPP, "Operation not supported"),
+        (c::ESOCKTNOSUPPORT, "Socket type not supported"),
+        (c::EPROTONOSUPPORT, "Protocol not supported"),
+        (c::ENOPROTOOPT, "Protocol not available"),
+        (c::EPROTOTYPE, "Protocol wrong type for socket"),
+        (c::EMSGSIZE, "Message too long"),
+        (c::ENOTSOCK, "Socket operation on non-socket"),
+        (c::EALREADY, "Operation already in progress"),
+        (c::EINPROGRESS, "Operation now in progress"),
+        (c::EAGAIN, "Resource temporarily unavailable"),
+        (c::ERANGE, "Numerical result out of range"),
+        (c::EDOM, "Numerical argument out of domain"),
+        (c::EPIPE, "Broken pipe"),
+        (c::EMLINK, "Too many links"),
+        (c::EROFS, "Read-only file system"),
+        (c::ESPIPE, "Illegal seek"),
+        (c::ENOSPC, "No space left on device"),
+        (c::EFBIG, "File too large"),
+        (c::ETXTBSY, "Text file busy"),
+        (c::ENOTTY, "Inappropriate ioctl for device"),
+        (c::ENFILE, "Too many open files in system"),
+        (c::EMFILE, "Too many open files"),
+        (c::EINVAL, "Invalid argument"),
+        (c::EISDIR, "Is a directory"),
+        (c::ENOTDIR, "Not a directory"),
+        (c::ENODEV, "No such device"),
+        (c::EXDEV, "Invalid cross-device link"),
+        (c::EEXIST, "File exists"),
+        (c::EBUSY, "Device or resource busy"),
+        (c::ENOTBLK, "Block device required"),
+        (c::EFAULT, "Bad address"),
+        (c::EACCES, "Permission denied"),
+        (c::ENOMEM, "Cannot allocate memory"),
+        (c::EDEADLK, "Resource deadlock avoided"),
+        (c::ECHILD, "No child processes"),
+        (c::EBADF, "Bad file descriptor"),
+        (c::ENOEXEC, "Exec format error"),
+        (c::E2BIG, "Argument list too long"),
+        (c::ENXIO, "No such device or address"),
+        (c::EIO, "Input/output error"),
+        (c::EINTR, "Interrupted system call"),
+        (c::ESRCH, "No such process"),
+        (c::ENOENT, "No such file or directory"),
+        (c::EPERM, "Operation not permitted"),
+    ];
+    let mut res = vec![];
+    for &(idx, msg) in MSGS {
+        let idx = idx as usize;
+        while res.len() <= idx {
+            res.push(None);
+        }
+        res[idx] = Some(msg);
+    }
+    res.leak()
+});
+
+#[derive(Debug, Eq, PartialEq)]
+pub struct OsError(pub c::c_int);
+
+impl From<c::c_int> for OsError {
+    fn from(v: c_int) -> Self {
+        Self(v)
+    }
+}
+
+impl From<std::io::Error> for OsError {
+    fn from(v: std::io::Error) -> Self {
+        match v.raw_os_error() {
+            Some(v) => Self(v),
+            None => Self(c::EINVAL),
+        }
+    }
+}
+
+impl Default for OsError {
+    fn default() -> Self {
+        OsError(Errno::default().0)
+    }
+}
+
+impl Error for OsError {}
+
+impl Display for OsError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let msg = ERRORS
+            .get(self.0 as usize)
+            .and_then(|v| *v)
+            .unwrap_or("unknown error");
+        write!(f, "{} (os error {})", msg, self.0)
+    }
+}
+
+pub trait OsErrorExt {
+    type Container;
+
+    fn to_os_error(self) -> Self::Container;
+}
+
+impl<T> OsErrorExt for Result<T, Errno> {
+    type Container = Result<T, OsError>;
+
+    fn to_os_error(self) -> Self::Container {
+        match self {
+            Ok(v) => Ok(v),
+            Err(e) => Err(OsError(e.0)),
+        }
+    }
+}
+
+pub trait OsErrorExt2 {
+    type T;
+
+    fn map_os_err<F, O>(self, op: O) -> Result<Self::T, F>
+    where
+        O: FnOnce(OsError) -> F;
+}
+
+impl<T> OsErrorExt2 for Result<T, Errno> {
+    type T = T;
+
+    fn map_os_err<F, O>(self, op: O) -> Result<T, F>
+    where
+        O: FnOnce(OsError) -> F,
+    {
+        match self {
+            Ok(t) => Ok(t),
+            Err(e) => Err(op(OsError(e.0))),
+        }
+    }
+}
--- a/crates/utils/src/page_size.rs
+++ b/crates/utils/src/page_size.rs
@ -0,0 +1,8 @@
+use {std::sync::LazyLock, uapi::c};
+
+static PAGE_SIZE: LazyLock<usize> =
+    LazyLock::new(|| uapi::sysconf(c::_SC_PAGESIZE).unwrap_or(4096) as _);
+
+pub fn page_size() -> usize {
+    *PAGE_SIZE
+}
--- a/crates/utils/src/pid_info.rs
+++ b/crates/utils/src/pid_info.rs
@ -0,0 +1,59 @@
+use {
+    crate::{errorfmt::ErrorFmt, oserror::OsErrorExt},
+    bstr::ByteSlice,
+    std::os::unix::ffi::OsStrExt,
+    uapi::{OwnedFd, c},
+};
+
+pub struct PidInfo {
+    pub uid: c::uid_t,
+    pub pid: c::pid_t,
+    pub comm: String,
+    pub exe: String,
+}
+
+pub fn get_pid_info(uid: c::uid_t, pid: c::pid_t) -> PidInfo {
+    let comm = match std::fs::read(format!("/proc/{}/comm", pid)) {
+        Ok(name) => name.trim_ascii_end().as_bstr().to_string(),
+        Err(e) => {
+            log::warn!("Could not read `comm` of pid {}: {}", pid, ErrorFmt(e));
+            "Unknown".to_string()
+        }
+    };
+    let exe = match std::fs::read_link(format!("/proc/{}/exe", pid)) {
+        Ok(name) => name
+            .as_os_str()
+            .as_bytes()
+            .trim_ascii_end()
+            .as_bstr()
+            .to_string(),
+        Err(e) => {
+            log::warn!("Could not read `exe` of pid {}: {}", pid, ErrorFmt(e));
+            "Unknown".to_string()
+        }
+    };
+    PidInfo {
+        uid,
+        pid,
+        comm,
+        exe,
+    }
+}
+
+pub fn get_socket_creds(socket: &OwnedFd) -> Option<(c::uid_t, c::pid_t)> {
+    let mut cred = c::ucred {
+        pid: 0,
+        uid: 0,
+        gid: 0,
+    };
+    match uapi::getsockopt(socket.raw(), c::SOL_SOCKET, c::SO_PEERCRED, &mut cred).to_os_error() {
+        Ok(_) => Some((cred.uid, cred.pid)),
+        Err(e) => {
+            log::error!(
+                "Cannot determine peer credentials of new connection: {}",
+                ErrorFmt(e),
+            );
+            None
+        }
+    }
+}
--- a/crates/utils/src/pidfd_send_signal.rs
+++ b/crates/utils/src/pidfd_send_signal.rs
@ -0,0 +1,23 @@
+use {
+    crate::oserror::{OsError, OsErrorExt},
+    c::{c_int, syscall},
+    std::{ptr, rc::Rc},
+    uapi::{
+        OwnedFd,
+        c::{self, SYS_pidfd_send_signal, siginfo_t},
+        map_err,
+    },
+};
+
+pub fn pidfd_send_signal(pidfd: &Rc<OwnedFd>, signal: c_int) -> Result<(), OsError> {
+    let res = unsafe {
+        syscall(
+            SYS_pidfd_send_signal,
+            pidfd.raw(),
+            signal,
+            ptr::null_mut::<siginfo_t>(),
+            0,
+        )
+    };
+    map_err!(res).map(drop).to_os_error()
+}
--- a/crates/utils/src/pipe.rs
+++ b/crates/utils/src/pipe.rs
@ -0,0 +1,32 @@
+use {
+    crate::oserror::{OsError, OsErrorExt},
+    uapi::{OwnedFd, c, pipe2},
+};
+
+pub struct Pipe<L, R> {
+    pub read: L,
+    pub write: R,
+}
+
+pub fn pipe() -> Result<Pipe<OwnedFd, OwnedFd>, OsError> {
+    let (read, write) = pipe2(c::O_CLOEXEC).to_os_error()?;
+    Ok(Pipe { read, write })
+}
+
+impl<L, R> Pipe<L, R> {
+    #[allow(dead_code)]
+    pub fn map_read<Lprime>(self, map: impl FnOnce(L) -> Lprime) -> Pipe<Lprime, R> {
+        Pipe {
+            read: map(self.read),
+            write: self.write,
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn map_write<Rprime>(self, map: impl FnOnce(R) -> Rprime) -> Pipe<L, Rprime> {
+        Pipe {
+            read: self.read,
+            write: map(self.write),
+        }
+    }
+}
--- a/crates/utils/src/process_name.rs
+++ b/crates/utils/src/process_name.rs
@ -0,0 +1,8 @@
+use uapi::{IntoUstr, c};
+
+pub fn set_process_name(name: &str) {
+    unsafe {
+        let name = name.into_ustr();
+        c::prctl(c::PR_SET_NAME, name.as_ptr());
+    }
+}
--- a/crates/utils/src/ptr_ext.rs
+++ b/crates/utils/src/ptr_ext.rs
@ -0,0 +1,28 @@
+pub trait PtrExt<T: ?Sized> {
+    unsafe fn deref<'a>(self) -> &'a T;
+}
+
+pub trait MutPtrExt<T: ?Sized> {
+    unsafe fn deref_mut<'a>(self) -> &'a mut T;
+}
+
+impl<T: ?Sized> PtrExt<T> for *const T {
+    #[inline(always)]
+    unsafe fn deref<'a>(self) -> &'a T {
+        unsafe { &*self }
+    }
+}
+
+impl<T: ?Sized> PtrExt<T> for *mut T {
+    #[inline(always)]
+    unsafe fn deref<'a>(self) -> &'a T {
+        unsafe { &*self }
+    }
+}
+
+impl<T: ?Sized> MutPtrExt<T> for *mut T {
+    #[inline(always)]
+    unsafe fn deref_mut<'a>(self) -> &'a mut T {
+        unsafe { &mut *self }
+    }
+}
--- a/crates/utils/src/queue.rs
+++ b/crates/utils/src/queue.rs
@ -0,0 +1,107 @@
+use {
+    crate::ptr_ext::{MutPtrExt, PtrExt},
+    std::{
+        cell::{Cell, UnsafeCell},
+        collections::VecDeque,
+        future::Future,
+        mem,
+        pin::Pin,
+        task::{Context, Poll, Waker},
+    },
+};
+
+pub struct AsyncQueue<T> {
+    data: UnsafeCell<VecDeque<T>>,
+    waiter: Cell<Option<Waker>>,
+}
+
+impl<T> Default for AsyncQueue<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T> AsyncQueue<T> {
+    pub fn new() -> Self {
+        Self {
+            data: Default::default(),
+            waiter: Default::default(),
+        }
+    }
+
+    pub fn push(&self, t: T) {
+        unsafe {
+            self.data.get().deref_mut().push_back(t);
+        }
+        if let Some(waiter) = self.waiter.take() {
+            waiter.wake();
+        }
+    }
+
+    pub fn try_pop(&self) -> Option<T> {
+        unsafe { self.data.get().deref_mut().pop_front() }
+    }
+
+    pub fn pop<'a>(&'a self) -> AsyncQueuePop<'a, T> {
+        AsyncQueuePop { queue: self }
+    }
+
+    pub fn non_empty<'a>(&'a self) -> AsyncQueueNonEmpty<'a, T> {
+        AsyncQueueNonEmpty { queue: self }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        unsafe { self.data.get().deref().is_empty() }
+    }
+
+    pub fn is_not_empty(&self) -> bool {
+        !self.is_empty()
+    }
+
+    pub fn clear(&self) {
+        unsafe {
+            mem::take(self.data.get().deref_mut());
+        }
+        self.waiter.take();
+    }
+
+    pub fn move_to(&self, other: &mut VecDeque<T>) {
+        unsafe {
+            other.append(self.data.get().deref_mut());
+        }
+    }
+}
+
+pub struct AsyncQueuePop<'a, T> {
+    queue: &'a AsyncQueue<T>,
+}
+
+impl<'a, T> Future for AsyncQueuePop<'a, T> {
+    type Output = T;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        if let Some(t) = self.queue.try_pop() {
+            Poll::Ready(t)
+        } else {
+            self.queue.waiter.set(Some(cx.waker().clone()));
+            Poll::Pending
+        }
+    }
+}
+
+pub struct AsyncQueueNonEmpty<'a, T> {
+    queue: &'a AsyncQueue<T>,
+}
+
+impl<'a, T> Future for AsyncQueueNonEmpty<'a, T> {
+    type Output = ();
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        if unsafe { self.queue.data.get().deref().len() } > 0 {
+            Poll::Ready(())
+        } else {
+            self.queue.waiter.set(Some(cx.waker().clone()));
+            Poll::Pending
+        }
+    }
+}
--- a/crates/utils/src/rc_eq.rs
+++ b/crates/utils/src/rc_eq.rs
@ -0,0 +1,37 @@
+use std::{
+    ops::Deref,
+    rc::{Rc, Weak},
+};
+
+pub fn rc_eq<T: ?Sized>(a: &Rc<T>, b: &Rc<T>) -> bool {
+    Rc::as_ptr(a) as *const u8 == Rc::as_ptr(b) as *const u8
+}
+
+pub fn rc_weak_eq<T: ?Sized>(a: &Rc<T>, b: &Weak<T>) -> bool {
+    Rc::as_ptr(a) as *const u8 == b.as_ptr() as *const u8
+}
+
+#[derive(Default)]
+pub struct RcEq<T>(pub Rc<T>);
+
+impl<T> Clone for RcEq<T> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+}
+
+impl<T> PartialEq for RcEq<T> {
+    fn eq(&self, other: &Self) -> bool {
+        rc_eq(&self.0, &other.0)
+    }
+}
+
+impl<T> Eq for RcEq<T> {}
+
+impl<T> Deref for RcEq<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
--- a/crates/utils/src/refcounted.rs
+++ b/crates/utils/src/refcounted.rs
@ -0,0 +1,90 @@
+use {
+    crate::ptr_ext::{MutPtrExt, PtrExt},
+    std::{cell::UnsafeCell, mem, ops::Deref},
+};
+
+pub struct RefCounted<T> {
+    map: UnsafeCell<Vec<(T, usize)>>,
+}
+
+impl<T> Default for RefCounted<T> {
+    fn default() -> Self {
+        Self {
+            map: UnsafeCell::new(vec![]),
+        }
+    }
+}
+
+impl<T: Eq> RefCounted<T> {
+    pub fn add(&self, t: T) -> bool {
+        unsafe {
+            let map = self.map.get().deref_mut();
+            for (k, v) in &mut *map {
+                if k == &t {
+                    *v += 1;
+                    return false;
+                }
+            }
+            map.push((t, 1));
+            true
+        }
+    }
+
+    pub fn remove(&self, t: &T) -> bool {
+        unsafe {
+            let map = self.map.get().deref_mut();
+            let idx = 'idx: {
+                for (idx, (k, v)) in map.iter_mut().enumerate() {
+                    if k == t {
+                        *v -= 1;
+                        if *v > 0 {
+                            return false;
+                        } else {
+                            break 'idx idx;
+                        }
+                    }
+                }
+                return false;
+            };
+            let _v = map.swap_remove(idx);
+            true
+        }
+    }
+
+    pub fn to_vec(&self) -> Vec<T>
+    where
+        T: Copy,
+    {
+        unsafe { self.map.get().deref().iter().map(|k| k.0).collect() }
+    }
+
+    pub fn lock(&self) -> Locked<'_, T> {
+        unsafe {
+            Locked {
+                vec: mem::take(self.map.get().deref_mut()),
+                rc: self,
+            }
+        }
+    }
+}
+
+pub struct Locked<'a, T> {
+    rc: &'a RefCounted<T>,
+    vec: Vec<(T, usize)>,
+}
+
+impl<'a, T> Deref for Locked<'a, T> {
+    type Target = [(T, usize)];
+
+    fn deref(&self) -> &Self::Target {
+        &self.vec
+    }
+}
+
+impl<'a, T> Drop for Locked<'a, T> {
+    fn drop(&mut self) {
+        unsafe {
+            *self.rc.map.get() = mem::take(&mut self.vec);
+        }
+    }
+}
--- a/crates/utils/src/smallmap.rs
+++ b/crates/utils/src/smallmap.rs
@ -0,0 +1,319 @@
+use {
+    crate::{
+        clonecell::UnsafeCellCloneSafe,
+        ptr_ext::{MutPtrExt, PtrExt},
+    },
+    smallvec::SmallVec,
+    std::{
+        cell::UnsafeCell,
+        fmt::{Debug, Formatter},
+        mem,
+    },
+};
+
+pub struct SmallMap<K, V, const N: usize> {
+    m: UnsafeCell<SmallMapMut<K, V, N>>,
+}
+
+impl<K: Debug, V: Debug, const N: usize> Debug for SmallMap<K, V, N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        unsafe { self.m.get().deref().fmt(f) }
+    }
+}
+
+impl<K, V, const N: usize> Default for SmallMap<K, V, N> {
+    fn default() -> Self {
+        Self {
+            m: Default::default(),
+        }
+    }
+}
+
+impl<K: Eq, V, const N: usize> SmallMap<K, V, N> {
+    pub fn new_with(k: K, v: V) -> Self {
+        Self {
+            m: UnsafeCell::new(SmallMapMut::new_with(k, v)),
+        }
+    }
+
+    pub fn new() -> Self {
+        Self {
+            m: UnsafeCell::new(SmallMapMut::new()),
+        }
+    }
+
+    pub fn contains(&self, k: &K) -> bool {
+        unsafe { self.m.get().deref().contains(k) }
+    }
+
+    pub fn len(&self) -> usize {
+        unsafe { self.m.get().deref().len() }
+    }
+
+    pub fn insert(&self, k: K, v: V) -> Option<V> {
+        unsafe { self.m.get().deref_mut().insert(k, v) }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        unsafe { self.m.get().deref().is_empty() }
+    }
+
+    pub fn is_not_empty(&self) -> bool {
+        !self.is_empty()
+    }
+
+    pub fn remove(&self, k: &K) -> Option<V> {
+        unsafe { self.m.get().deref_mut().remove(k) }
+    }
+
+    pub fn clear(&self) {
+        unsafe {
+            self.m.get().deref_mut().clear();
+        }
+    }
+
+    pub fn take(&self) -> SmallVec<[(K, V); N]> {
+        unsafe { self.m.get().deref_mut().take() }
+    }
+
+    pub fn replace(&self, other: SmallVec<[(K, V); N]>) -> SmallVec<[(K, V); N]> {
+        unsafe { mem::replace(&mut self.m.get().deref_mut().m, other) }
+    }
+
+    pub fn pop(&self) -> Option<(K, V)> {
+        unsafe { self.m.get().deref_mut().pop() }
+    }
+
+    pub fn iter<'a>(&'a self) -> SmallMapIter<'a, K, V, N> {
+        SmallMapIter { pos: 0, map: self }
+    }
+}
+
+impl<K: Eq, V: UnsafeCellCloneSafe, const N: usize> SmallMap<K, V, N> {
+    pub fn get(&self, k: &K) -> Option<V> {
+        unsafe {
+            let m = &self.m.get().deref().m;
+            for (ek, ev) in m {
+                if ek == k {
+                    return Some(ev.clone());
+                }
+            }
+            None
+        }
+    }
+}
+
+impl<'a, K: Copy, V: UnsafeCellCloneSafe, const N: usize> IntoIterator for &'a SmallMap<K, V, N> {
+    type Item = (K, V);
+    type IntoIter = SmallMapIter<'a, K, V, N>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        SmallMapIter { pos: 0, map: self }
+    }
+}
+
+pub struct SmallMapIter<'a, K, V, const N: usize> {
+    pos: usize,
+    map: &'a SmallMap<K, V, N>,
+}
+
+impl<'a, K: Copy, V: UnsafeCellCloneSafe, const N: usize> Iterator for SmallMapIter<'a, K, V, N> {
+    type Item = (K, V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        unsafe {
+            let v = &self.map.m.get().deref().m;
+            if self.pos >= v.len() {
+                return None;
+            }
+            let (k, v) = &v[self.pos];
+            self.pos += 1;
+            Some((*k, v.clone()))
+        }
+    }
+}
+
+pub struct SmallMapMut<K, V, const N: usize> {
+    m: SmallVec<[(K, V); N]>,
+}
+
+impl<K: Debug, V: Debug, const N: usize> Debug for SmallMapMut<K, V, N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_map()
+            .entries(self.m.iter().map(|e| (&e.0, &e.1)))
+            .finish()
+    }
+}
+
+impl<K, V, const N: usize> Default for SmallMapMut<K, V, N> {
+    fn default() -> Self {
+        Self {
+            m: Default::default(),
+        }
+    }
+}
+
+impl<K: Eq, V, const N: usize> SmallMapMut<K, V, N> {
+    pub fn new_with(k: K, v: V) -> Self {
+        let mut sv = SmallVec::new();
+        sv.push((k, v));
+        Self { m: sv }
+    }
+
+    pub fn new() -> Self {
+        Self {
+            m: SmallVec::new_const(),
+        }
+    }
+
+    pub fn len(&self) -> usize {
+        self.m.len()
+    }
+
+    pub fn contains(&self, k: &K) -> bool {
+        for (ek, _) in &self.m {
+            if ek == k {
+                return true;
+            }
+        }
+        false
+    }
+
+    pub fn insert(&mut self, k: K, v: V) -> Option<V> {
+        for (ek, ev) in &mut self.m {
+            if ek == &k {
+                return Some(mem::replace(ev, v));
+            }
+        }
+        self.m.push((k, v));
+        None
+    }
+
+    pub fn get(&self, k: &K) -> Option<&V> {
+        for (ek, ev) in &self.m {
+            if ek == k {
+                return Some(ev);
+            }
+        }
+        None
+    }
+
+    pub fn get_mut(&mut self, k: &K) -> Option<&mut V> {
+        for (ek, ev) in &mut self.m {
+            if ek == k {
+                return Some(ev);
+            }
+        }
+        None
+    }
+
+    pub fn get_or_default_mut(&mut self, k: K) -> &mut V
+    where
+        V: Default,
+    {
+        self.get_or_insert_with(k, || V::default())
+    }
+
+    pub fn get_or_insert_with<F>(&mut self, k: K, f: F) -> &mut V
+    where
+        F: FnOnce() -> V,
+    {
+        for (ek, ev) in &mut self.m {
+            if ek == &k {
+                return unsafe { (ev as *mut V).deref_mut() };
+            }
+        }
+        self.m.push((k, f()));
+        &mut self.m.last_mut().unwrap().1
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.m.is_empty()
+    }
+
+    pub fn remove(&mut self, k: &K) -> Option<V> {
+        for (idx, (ek, _)) in self.m.iter_mut().enumerate() {
+            if ek == k {
+                return Some(self.m.swap_remove(idx).1);
+            }
+        }
+        None
+    }
+
+    pub fn clear(&mut self) {
+        let _v = mem::replace(&mut self.m, SmallVec::new());
+    }
+
+    pub fn take(&mut self) -> SmallVec<[(K, V); N]> {
+        mem::take(&mut self.m)
+    }
+
+    pub fn pop(&mut self) -> Option<(K, V)> {
+        self.m.pop()
+    }
+
+    pub fn iter<'a>(&'a self) -> SmallMapMutIter<'a, K, V, N> {
+        SmallMapMutIter { pos: 0, map: self }
+    }
+
+    pub fn iter_mut<'a>(&'a mut self) -> SmallMapMutIterMut<'a, K, V, N> {
+        SmallMapMutIterMut { pos: 0, map: self }
+    }
+
+    pub fn remove_if<F: FnMut(&K, &V) -> bool>(&mut self, mut f: F) {
+        let mut i = 0;
+        while i < self.m.len() {
+            let (k, v) = &self.m[i];
+            if f(k, v) {
+                self.m.swap_remove(i);
+            } else {
+                i += 1;
+            }
+        }
+    }
+}
+
+impl<'a, K: Copy, V, const N: usize> IntoIterator for &'a SmallMapMut<K, V, N> {
+    type Item = (&'a K, &'a V);
+    type IntoIter = SmallMapMutIter<'a, K, V, N>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        SmallMapMutIter { pos: 0, map: self }
+    }
+}
+
+pub struct SmallMapMutIter<'a, K, V, const N: usize> {
+    pos: usize,
+    map: &'a SmallMapMut<K, V, N>,
+}
+
+impl<'a, K, V, const N: usize> Iterator for SmallMapMutIter<'a, K, V, N> {
+    type Item = (&'a K, &'a V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.pos >= self.map.m.len() {
+            return None;
+        }
+        let (k, v) = &self.map.m[self.pos];
+        self.pos += 1;
+        Some((k, v))
+    }
+}
+
+pub struct SmallMapMutIterMut<'a, K, V, const N: usize> {
+    pos: usize,
+    map: &'a mut SmallMapMut<K, V, N>,
+}
+
+impl<'a, K, V, const N: usize> Iterator for SmallMapMutIterMut<'a, K, V, N> {
+    type Item = (&'a mut K, &'a mut V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.pos >= self.map.m.len() {
+            return None;
+        }
+        let (k, v) = &mut self.map.m[self.pos];
+        self.pos += 1;
+        unsafe { Some(((k as *mut K).deref_mut(), (v as *mut V).deref_mut())) }
+    }
+}
--- a/crates/utils/src/stack.rs
+++ b/crates/utils/src/stack.rs
@ -0,0 +1,49 @@
+use {
+    crate::{
+        clonecell::UnsafeCellCloneSafe,
+        ptr_ext::{MutPtrExt, PtrExt},
+    },
+    std::{cell::UnsafeCell, mem},
+};
+
+pub struct Stack<T> {
+    vec: UnsafeCell<Vec<T>>,
+}
+
+impl<T> Default for Stack<T> {
+    fn default() -> Self {
+        Self {
+            vec: Default::default(),
+        }
+    }
+}
+
+impl<T> Stack<T> {
+    pub fn push(&self, v: T) {
+        unsafe {
+            self.vec.get().deref_mut().push(v);
+        }
+    }
+
+    pub fn pop(&self) -> Option<T> {
+        unsafe { self.vec.get().deref_mut().pop() }
+    }
+
+    pub fn to_vec(&self) -> Vec<T>
+    where
+        T: UnsafeCellCloneSafe,
+    {
+        unsafe {
+            let v = self.vec.get().deref();
+            (*v).clone()
+        }
+    }
+
+    pub fn take(&self) -> Vec<T> {
+        unsafe { mem::take(self.vec.get().deref_mut()) }
+    }
+
+    pub fn len(&self) -> usize {
+        unsafe { self.vec.get().deref().len() }
+    }
+}
--- a/crates/utils/src/static_text.rs
+++ b/crates/utils/src/static_text.rs
@ -0,0 +1,3 @@
+pub trait StaticText {
+    fn text(&self) -> &'static str;
+}
--- a/crates/utils/src/string_ext.rs
+++ b/crates/utils/src/string_ext.rs
@ -0,0 +1,11 @@
+use isnt::std_1::primitive::IsntStrExt;
+
+pub trait StringExt {
+    fn to_string_if_not_empty(&self) -> Option<String>;
+}
+
+impl StringExt for str {
+    fn to_string_if_not_empty(&self) -> Option<String> {
+        self.is_not_empty().then(|| self.to_string())
+    }
+}
--- a/crates/utils/src/syncqueue.rs
+++ b/crates/utils/src/syncqueue.rs
@ -0,0 +1,68 @@
+use {
+    crate::ptr_ext::MutPtrExt,
+    std::{cell::UnsafeCell, collections::VecDeque, mem},
+};
+
+#[derive(Debug)]
+pub struct SyncQueue<T> {
+    el: UnsafeCell<VecDeque<T>>,
+}
+
+impl<T> Default for SyncQueue<T> {
+    fn default() -> Self {
+        Self {
+            el: Default::default(),
+        }
+    }
+}
+
+impl<T> SyncQueue<T> {
+    pub fn push(&self, t: T) {
+        unsafe {
+            self.el.get().deref_mut().push_back(t);
+        }
+    }
+
+    pub fn push_front(&self, t: T) {
+        unsafe {
+            self.el.get().deref_mut().push_front(t);
+        }
+    }
+
+    pub fn append(&self, src: &mut Vec<T>) {
+        unsafe {
+            self.el.get().deref_mut().extend(src.drain(..));
+        }
+    }
+
+    #[inline]
+    pub fn pop(&self) -> Option<T> {
+        unsafe { self.el.get().deref_mut().pop_front() }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        unsafe { self.el.get().deref_mut().is_empty() }
+    }
+
+    pub fn is_not_empty(&self) -> bool {
+        !self.is_empty()
+    }
+
+    pub fn swap(&self, queue: &mut VecDeque<T>) {
+        unsafe {
+            mem::swap(self.el.get().deref_mut(), queue);
+        }
+    }
+
+    pub fn take(&self) -> VecDeque<T> {
+        let mut res = VecDeque::new();
+        self.swap(&mut res);
+        res
+    }
+
+    pub fn clear(&self) {
+        unsafe {
+            self.el.get().deref_mut().clear();
+        }
+    }
+}
--- a/crates/utils/src/threshold_counter.rs
+++ b/crates/utils/src/threshold_counter.rs
@ -0,0 +1,24 @@
+use crate::numcell::NumCell;
+
+#[derive(Default)]
+pub struct ThresholdCounter {
+    counter: NumCell<usize>,
+}
+
+impl ThresholdCounter {
+    pub fn inc(&self) -> bool {
+        self.counter.fetch_add(1) == 0
+    }
+
+    pub fn dec(&self) -> bool {
+        self.counter.fetch_sub(1) == 1
+    }
+
+    pub fn adj(&self, inc: bool) -> bool {
+        if inc { self.inc() } else { self.dec() }
+    }
+
+    pub fn active(&self) -> bool {
+        self.counter.get() > 0
+    }
+}
--- a/crates/utils/src/tri.rs
+++ b/crates/utils/src/tri.rs
@ -0,0 +1,51 @@
+use std::{
+    future::Future,
+    marker::PhantomData,
+    pin::Pin,
+    task::{Context, Poll},
+};
+
+pub trait Try: Sized {
+    fn tri<F>(f: F) -> Result<(), Self>
+    where
+        F: FnOnce() -> Result<(), Self>;
+
+    fn tria<F>(f: F) -> Tria<Self, F>
+    where
+        F: Future<Output = Result<(), Self>>;
+}
+
+impl<E> Try for E {
+    fn tri<F>(f: F) -> Result<(), Self>
+    where
+        F: FnOnce() -> Result<(), Self>,
+    {
+        f()
+    }
+
+    fn tria<F>(f: F) -> Tria<E, F>
+    where
+        F: Future<Output = Result<(), Self>>,
+    {
+        Tria {
+            f,
+            _phantom: Default::default(),
+        }
+    }
+}
+
+pub struct Tria<E, F> {
+    f: F,
+    _phantom: PhantomData<E>,
+}
+
+impl<E, F> Future for Tria<E, F>
+where
+    F: Future<Output = Result<(), E>>,
+{
+    type Output = Result<(), E>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        unsafe { Pin::new_unchecked(&mut Pin::get_unchecked_mut(self).f).poll(cx) }
+    }
+}
--- a/crates/utils/src/unlink_on_drop.rs
+++ b/crates/utils/src/unlink_on_drop.rs
@ -0,0 +1,7 @@
+pub struct UnlinkOnDrop<'a>(pub &'a str);
+
+impl<'a> Drop for UnlinkOnDrop<'a> {
+    fn drop(&mut self) {
+        let _ = uapi::unlink(self.0);
+    }
+}
--- a/crates/utils/src/vec_ext.rs
+++ b/crates/utils/src/vec_ext.rs
@ -0,0 +1,40 @@
+use std::{mem::MaybeUninit, ops::Range, slice};
+
+pub trait VecExt<T> {
+    fn split_at_spare_mut_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<T>]);
+    fn split_at_spare_mut_bytes_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<u8>]);
+}
+
+impl<T> VecExt<T> for Vec<T> {
+    fn split_at_spare_mut_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<T>]) {
+        let Range {
+            start: ptr,
+            end: spare_ptr,
+        } = self.as_mut_ptr_range();
+        let spare_ptr = spare_ptr.cast::<MaybeUninit<T>>();
+        let spare_len = self.capacity() - self.len();
+        unsafe {
+            let initialized = slice::from_raw_parts_mut(ptr, self.len());
+            let spare = slice::from_raw_parts_mut(spare_ptr, spare_len);
+            (initialized, spare)
+        }
+    }
+
+    fn split_at_spare_mut_bytes_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<u8>]) {
+        let (l, r) = self.split_at_spare_mut_ext();
+        unsafe { (l, uapi::as_maybe_uninit_bytes_mut2(r)) }
+    }
+}
+
+pub trait UninitVecExt<T> {
+    fn set_len_safe(&mut self, n: usize);
+}
+
+impl<T> UninitVecExt<T> for Vec<MaybeUninit<T>> {
+    fn set_len_safe(&mut self, n: usize) {
+        assert!(n <= self.capacity());
+        unsafe {
+            self.set_len(n);
+        }
+    }
+}
--- a/crates/utils/src/vecdeque_ext.rs
+++ b/crates/utils/src/vecdeque_ext.rs
@ -0,0 +1,35 @@
+use std::{
+    collections::{Bound, VecDeque},
+    ops::RangeBounds,
+};
+
+pub trait VecDequeExt<T> {
+    fn get_slices(&self, range: impl RangeBounds<usize>) -> (&[T], &[T]);
+}
+
+impl<T> VecDequeExt<T> for VecDeque<T> {
+    fn get_slices(&self, range: impl RangeBounds<usize>) -> (&[T], &[T]) {
+        let (l, r) = self.as_slices();
+        let start = match range.start_bound().cloned() {
+            Bound::Included(n) => n,
+            Bound::Excluded(n) => n + 1,
+            Bound::Unbounded => 0,
+        };
+        let end = match range.end_bound().cloned() {
+            Bound::Included(n) => n + 1,
+            Bound::Excluded(n) => n,
+            Bound::Unbounded => self.len(),
+        };
+        let left = {
+            let lo = start.min(l.len());
+            let hi = end.min(l.len());
+            &l[lo..hi]
+        };
+        let right = {
+            let lo = start.saturating_sub(l.len());
+            let hi = end.saturating_sub(l.len());
+            &r[lo..hi]
+        };
+        (left, right)
+    }
+}
--- a/crates/utils/src/vecset.rs
+++ b/crates/utils/src/vecset.rs
@ -0,0 +1,58 @@
+use std::ops::Deref;
+
+pub struct VecSet<T> {
+    vec: Vec<T>,
+}
+
+impl<T> Default for VecSet<T> {
+    fn default() -> Self {
+        Self { vec: vec![] }
+    }
+}
+
+impl<T> Deref for VecSet<T> {
+    type Target = [T];
+
+    fn deref(&self) -> &Self::Target {
+        &self.vec
+    }
+}
+
+impl<T> VecSet<T> {
+    pub fn clear(&mut self) {
+        self.vec.clear();
+    }
+}
+
+impl<T: PartialEq> VecSet<T> {
+    pub fn insert(&mut self, val: T) -> bool {
+        if self.vec.contains(&val) {
+            return false;
+        }
+        self.vec.push(val);
+        true
+    }
+
+    pub fn remove(&mut self, val: &T) -> bool {
+        for i in 0..self.vec.len() {
+            if self.vec[i] == *val {
+                self.vec.swap_remove(i);
+                return true;
+            }
+        }
+        false
+    }
+
+    pub fn pop(&mut self) -> Option<T> {
+        self.vec.pop()
+    }
+
+    pub fn extend(&mut self, vals: &[T])
+    where
+        T: Copy,
+    {
+        for v in vals.iter().copied() {
+            self.insert(v);
+        }
+    }
+}
--- a/crates/utils/src/vecstorage.rs
+++ b/crates/utils/src/vecstorage.rs
@ -0,0 +1,105 @@
+use std::{
+    mem::ManuallyDrop,
+    ops::{Deref, DerefMut},
+};
+
+macro_rules! assert_size_eq {
+    ($t:ty, $u:ty) => {{
+        struct AssertEqSize<T, U>(std::marker::PhantomData<T>, std::marker::PhantomData<U>);
+        impl<T, U> AssertEqSize<T, U> {
+            const VAL: usize = {
+                if std::mem::size_of::<T>() != std::mem::size_of::<U>() {
+                    panic!("Types have different size");
+                }
+                1
+            };
+        }
+        let _ = AssertEqSize::<$t, $u>::VAL;
+    }};
+}
+
+macro_rules! assert_align_eq {
+    ($t:ty, $u:ty) => {{
+        struct AssertEqAlign<T, U>(std::marker::PhantomData<T>, std::marker::PhantomData<U>);
+        impl<T, U> AssertEqAlign<T, U> {
+            const VAL: usize = {
+                if std::mem::align_of::<T>() != std::mem::align_of::<U>() {
+                    panic!("Types have different alignment");
+                }
+                1
+            };
+        }
+        let _ = AssertEqAlign::<$t, $u>::VAL;
+    }};
+}
+
+pub struct VecStorage<T> {
+    ptr: *mut T,
+    cap: usize,
+}
+
+impl<T> Default for VecStorage<T> {
+    fn default() -> Self {
+        let mut v = ManuallyDrop::new(vec![]);
+        Self {
+            ptr: v.as_mut_ptr(),
+            cap: v.capacity(),
+        }
+    }
+}
+
+impl<T> VecStorage<T> {
+    pub fn take<'a>(&'a mut self) -> RealizedVec<'a, T, T> {
+        self.take_as()
+    }
+
+    pub fn take_as<'a, U>(&'a mut self) -> RealizedVec<'a, T, U> {
+        assert_size_eq!(T, U);
+        assert_align_eq!(T, U);
+        unsafe {
+            RealizedVec {
+                vec: ManuallyDrop::new(self.to_vector()),
+                storage: self,
+            }
+        }
+    }
+
+    unsafe fn to_vector<U>(&mut self) -> Vec<U> {
+        unsafe { Vec::from_raw_parts(self.ptr as _, 0, self.cap) }
+    }
+}
+
+impl<T> Drop for VecStorage<T> {
+    fn drop(&mut self) {
+        unsafe {
+            drop(self.to_vector::<T>());
+        }
+    }
+}
+
+pub struct RealizedVec<'a, T, U> {
+    vec: ManuallyDrop<Vec<U>>,
+    storage: &'a mut VecStorage<T>,
+}
+
+impl<'a, T, U> Drop for RealizedVec<'a, T, U> {
+    fn drop(&mut self) {
+        self.vec.clear();
+        self.storage.ptr = self.vec.as_mut_ptr() as _;
+        self.storage.cap = self.vec.capacity();
+    }
+}
+
+impl<'a, T, U> Deref for RealizedVec<'a, T, U> {
+    type Target = Vec<U>;
+
+    fn deref(&self) -> &Self::Target {
+        self.vec.deref()
+    }
+}
+
+impl<'a, T, U> DerefMut for RealizedVec<'a, T, U> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.vec.deref_mut()
+    }
+}
--- a/crates/utils/src/windows.rs
+++ b/crates/utils/src/windows.rs
@ -0,0 +1,46 @@
+use crate::ptr_ext::PtrExt;
+
+pub trait WindowsExt<T> {
+    type Windows<'a, const N: usize>: Iterator<Item = &'a [T; N]>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn array_windows_ext<'a, const N: usize>(&'a self) -> Self::Windows<'a, N>;
+    fn array_chunks_ext<'a, const N: usize>(&'a self) -> &'a [[T; N]];
+}
+
+impl<T> WindowsExt<T> for [T] {
+    type Windows<'a, const N: usize>
+        = WindowsIter<'a, T, N>
+    where
+        T: 'a;
+
+    fn array_windows_ext<'a, const N: usize>(&'a self) -> Self::Windows<'a, N> {
+        WindowsIter { slice: self }
+    }
+
+    fn array_chunks_ext<'a, const N: usize>(&'a self) -> &'a [[T; N]] {
+        let len = self.len() / N;
+        unsafe { std::slice::from_raw_parts(self.as_ptr() as _, len) }
+    }
+}
+
+pub struct WindowsIter<'a, T, const N: usize> {
+    slice: &'a [T],
+}
+
+impl<'a, T, const N: usize> Iterator for WindowsIter<'a, T, N> {
+    type Item = &'a [T; N];
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.slice.len() < N {
+            return None;
+        }
+        let res = unsafe { self.slice.as_ptr().cast::<[T; N]>().deref() };
+        if N > 0 {
+            self.slice = &self.slice[1..];
+        }
+        Some(res)
+    }
+}
--- a/crates/utils/src/xrd.rs
+++ b/crates/utils/src/xrd.rs
@ -0,0 +1,5 @@
+pub const XRD: &str = "XDG_RUNTIME_DIR";
+
+pub fn xrd() -> Option<String> {
+    std::env::var(XRD).ok()
+}