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//! Implement Fallible HashMap
use super::TryClone;
use crate::TryReserveError;
use core::borrow::Borrow;
use core::default::Default;
use core::fmt::Debug;
use core::hash::Hash;
#[cfg(not(all(feature = "std", feature = "rust_1_57")))]
type HashMap<K, V> = hashbrown::hash_map::HashMap<K, V>;
#[cfg(all(feature = "std", feature = "rust_1_57"))]
type HashMap<K, V> = std::collections::HashMap<K, V>;
#[cfg(not(all(feature = "std", feature = "rust_1_57")))]
use hashbrown::hash_map::{Iter, IntoIter};
#[cfg(all(feature = "std", feature = "rust_1_57"))]
use std::collections::hash_map::{Iter, IntoIter};
pub struct TryHashMap<K, V> {
inner: HashMap<K, V>,
}
impl<K, V> Default for TryHashMap<K, V> {
#[inline(always)]
fn default() -> Self {
Self {
inner: Default::default(),
}
}
}
impl<K: Debug, V: Debug> Debug for TryHashMap<K, V> {
#[inline]
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
self.inner.fmt(f)
}
}
impl<K, V> TryHashMap<K, V>
where
K: Eq + Hash,
{
#[inline]
pub fn with_capacity(capacity: usize) -> Result<Self, TryReserveError> {
let mut map = Self {
inner: HashMap::new(),
};
map.reserve(capacity)?;
Ok(map)
}
#[inline(always)]
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.get(k)
}
#[inline]
pub fn insert(&mut self, k: K, v: V) -> Result<Option<V>, TryReserveError> {
self.reserve(if self.inner.capacity() == 0 { 4 } else { 1 })?;
Ok(self.inner.insert(k, v))
}
#[inline(always)]
pub fn iter(&self) -> Iter<'_, K, V> {
self.inner.iter()
}
#[inline(always)]
pub fn len(&self) -> usize {
self.inner.len()
}
#[inline(always)]
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.remove(k)
}
#[inline(always)]
fn reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
#[cfg(not(all(feature = "std", feature = "rust_1_57")))]
{
self.inner.try_reserve(additional)
}
#[cfg(all(feature = "std", feature = "rust_1_57"))]
{
self.inner.try_reserve(additional).map_err(|_| {
crate::make_try_reserve_error(self.len(), additional,
core::mem::size_of::<K>() + core::mem::size_of::<V>(),
core::mem::align_of::<K>().max(core::mem::align_of::<V>()),
)
})
}
}
}
impl<K, V> IntoIterator for TryHashMap<K, V> {
type Item = (K, V);
type IntoIter = IntoIter<K, V>;
#[inline(always)]
fn into_iter(self) -> Self::IntoIter {
self.inner.into_iter()
}
}
impl<K, V> TryClone for TryHashMap<K, V>
where
K: Eq + Hash + TryClone,
V: TryClone,
{
fn try_clone(&self) -> Result<Self, TryReserveError> {
let mut clone = Self::with_capacity(self.inner.len())?;
for (key, value) in self.inner.iter() {
clone.insert(key.try_clone()?, value.try_clone()?)?;
}
Ok(clone)
}
}
#[test]
fn tryhashmap_oom() {
match TryHashMap::<char, char>::default().reserve(core::usize::MAX) {
Ok(_) => panic!("it should be OOM"),
_ => (),
}
}