use super::one::RefMut;
use crate::lock::RwLockWriteGuard;
use crate::util;
use crate::util::SharedValue;
use crate::HashMap;
use core::hash::{BuildHasher, Hash};
use core::mem;
use core::ptr;
use std::collections::hash_map::RandomState;
pub enum Entry<'a, K, V, S = RandomState> {
Occupied(OccupiedEntry<'a, K, V, S>),
Vacant(VacantEntry<'a, K, V, S>),
}
impl<'a, K: Eq + Hash, V, S: BuildHasher> Entry<'a, K, V, S> {
pub fn and_modify(self, f: impl FnOnce(&mut V)) -> Self {
match self {
Entry::Occupied(mut entry) => {
f(entry.get_mut());
Entry::Occupied(entry)
}
Entry::Vacant(entry) => Entry::Vacant(entry),
}
}
pub fn key(&self) -> &K {
match *self {
Entry::Occupied(ref entry) => entry.key(),
Entry::Vacant(ref entry) => entry.key(),
}
}
pub fn into_key(self) -> K {
match self {
Entry::Occupied(entry) => entry.into_key(),
Entry::Vacant(entry) => entry.into_key(),
}
}
pub fn or_default(self) -> RefMut<'a, K, V, S>
where
V: Default,
{
match self {
Entry::Occupied(entry) => entry.into_ref(),
Entry::Vacant(entry) => entry.insert(V::default()),
}
}
pub fn or_insert(self, value: V) -> RefMut<'a, K, V, S> {
match self {
Entry::Occupied(entry) => entry.into_ref(),
Entry::Vacant(entry) => entry.insert(value),
}
}
pub fn or_insert_with(self, value: impl FnOnce() -> V) -> RefMut<'a, K, V, S> {
match self {
Entry::Occupied(entry) => entry.into_ref(),
Entry::Vacant(entry) => entry.insert(value()),
}
}
pub fn or_try_insert_with<E>(
self,
value: impl FnOnce() -> Result<V, E>,
) -> Result<RefMut<'a, K, V, S>, E> {
match self {
Entry::Occupied(entry) => Ok(entry.into_ref()),
Entry::Vacant(entry) => Ok(entry.insert(value()?)),
}
}
pub fn insert(self, value: V) -> RefMut<'a, K, V, S> {
match self {
Entry::Occupied(mut entry) => {
entry.insert(value);
entry.into_ref()
}
Entry::Vacant(entry) => entry.insert(value),
}
}
pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V, S>
where
K: Clone,
{
match self {
Entry::Occupied(mut entry) => {
entry.insert(value);
entry
}
Entry::Vacant(entry) => entry.insert_entry(value),
}
}
}
pub struct VacantEntry<'a, K, V, S = RandomState> {
shard: RwLockWriteGuard<'a, HashMap<K, V, S>>,
key: K,
}
unsafe impl<'a, K: Eq + Hash + Sync, V: Sync, S: BuildHasher> Send for VacantEntry<'a, K, V, S> {}
unsafe impl<'a, K: Eq + Hash + Sync, V: Sync, S: BuildHasher> Sync for VacantEntry<'a, K, V, S> {}
impl<'a, K: Eq + Hash, V, S: BuildHasher> VacantEntry<'a, K, V, S> {
pub(crate) unsafe fn new(shard: RwLockWriteGuard<'a, HashMap<K, V, S>>, key: K) -> Self {
Self { shard, key }
}
pub fn insert(mut self, value: V) -> RefMut<'a, K, V, S> {
unsafe {
let c: K = ptr::read(&self.key);
self.shard.insert(self.key, SharedValue::new(value));
let (k, v) = self.shard.get_key_value(&c).unwrap();
let k = util::change_lifetime_const(k);
let v = &mut *v.as_ptr();
let r = RefMut::new(self.shard, k, v);
mem::forget(c);
r
}
}
pub fn insert_entry(mut self, value: V) -> OccupiedEntry<'a, K, V, S>
where
K: Clone,
{
unsafe {
self.shard.insert(self.key.clone(), SharedValue::new(value));
let (k, v) = self.shard.get_key_value(&self.key).unwrap();
let kptr: *const K = k;
let vptr: *mut V = v.as_ptr();
OccupiedEntry::new(self.shard, self.key, (kptr, vptr))
}
}
pub fn into_key(self) -> K {
self.key
}
pub fn key(&self) -> &K {
&self.key
}
}
pub struct OccupiedEntry<'a, K, V, S = RandomState> {
shard: RwLockWriteGuard<'a, HashMap<K, V, S>>,
elem: (*const K, *mut V),
key: K,
}
unsafe impl<'a, K: Eq + Hash + Sync, V: Sync, S: BuildHasher> Send for OccupiedEntry<'a, K, V, S> {}
unsafe impl<'a, K: Eq + Hash + Sync, V: Sync, S: BuildHasher> Sync for OccupiedEntry<'a, K, V, S> {}
impl<'a, K: Eq + Hash, V, S: BuildHasher> OccupiedEntry<'a, K, V, S> {
pub(crate) unsafe fn new(
shard: RwLockWriteGuard<'a, HashMap<K, V, S>>,
key: K,
elem: (*const K, *mut V),
) -> Self {
Self { shard, elem, key }
}
pub fn get(&self) -> &V {
unsafe { &*self.elem.1 }
}
pub fn get_mut(&mut self) -> &mut V {
unsafe { &mut *self.elem.1 }
}
pub fn insert(&mut self, value: V) -> V {
mem::replace(self.get_mut(), value)
}
pub fn into_ref(self) -> RefMut<'a, K, V, S> {
unsafe { RefMut::new(self.shard, self.elem.0, self.elem.1) }
}
pub fn into_key(self) -> K {
self.key
}
pub fn key(&self) -> &K {
unsafe { &*self.elem.0 }
}
pub fn remove(mut self) -> V {
let key = unsafe { &*self.elem.0 };
self.shard.remove(key).unwrap().into_inner()
}
pub fn remove_entry(mut self) -> (K, V) {
let key = unsafe { &*self.elem.0 };
let (k, v) = self.shard.remove_entry(key).unwrap();
(k, v.into_inner())
}
pub fn replace_entry(mut self, value: V) -> (K, V) {
let nk = self.key;
let key = unsafe { &*self.elem.0 };
let (k, v) = self.shard.remove_entry(key).unwrap();
self.shard.insert(nk, SharedValue::new(value));
(k, v.into_inner())
}
}
#[cfg(test)]
mod tests {
use crate::DashMap;
use super::*;
#[test]
fn test_insert_entry_into_vacant() {
let map: DashMap<u32, u32> = DashMap::new();
let entry = map.entry(1);
assert!(matches!(entry, Entry::Vacant(_)));
let entry = entry.insert_entry(2);
assert_eq!(*entry.get(), 2);
drop(entry);
assert_eq!(*map.get(&1).unwrap(), 2);
}
#[test]
fn test_insert_entry_into_occupied() {
let map: DashMap<u32, u32> = DashMap::new();
map.insert(1, 1000);
let entry = map.entry(1);
assert!(matches!(&entry, Entry::Occupied(entry) if *entry.get() == 1000));
let entry = entry.insert_entry(2);
assert_eq!(*entry.get(), 2);
drop(entry);
assert_eq!(*map.get(&1).unwrap(), 2);
}
}