| //! A hash set where the elements are held by weak pointers and compared by value. |
| |
| use crate::compat::*; |
| |
| use super::traits::*; |
| use super::weak_key_hash_map as base; |
| |
| pub use super::WeakHashSet; |
| |
| impl <T: WeakKey> WeakHashSet<T, RandomState> { |
| /// Creates an empty `WeakHashSet`. |
| /// |
| /// *O*(1) time |
| pub fn new() -> Self { |
| WeakHashSet(base::WeakKeyHashMap::new()) |
| } |
| |
| /// Creates an empty `WeakHashSet` with the given capacity. |
| /// |
| /// *O*(*n*) time |
| pub fn with_capacity(capacity: usize) -> Self { |
| WeakHashSet(base::WeakKeyHashMap::with_capacity(capacity)) |
| } |
| } |
| |
| impl <T: WeakKey, S: BuildHasher> WeakHashSet<T, S> { |
| /// Creates an empty `WeakHashSet` with the given capacity and hasher. |
| /// |
| /// *O*(*n*) time |
| pub fn with_hasher(hash_builder: S) -> Self { |
| WeakHashSet(base::WeakKeyHashMap::with_hasher(hash_builder)) |
| } |
| |
| /// Creates an empty `WeakHashSet` with the given capacity and hasher. |
| /// |
| /// *O*(*n*) time |
| pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> Self { |
| WeakHashSet(base::WeakKeyHashMap::with_capacity_and_hasher(capacity, hash_builder)) |
| } |
| |
| /// Returns a reference to the map's `BuildHasher`. |
| /// |
| /// *O*(1) time |
| pub fn hasher(&self) -> &S { |
| self.0.hasher() |
| } |
| |
| /// Returns the number of elements the map can hold without reallocating. |
| /// |
| /// *O*(1) time |
| pub fn capacity(&self) -> usize { |
| self.0.capacity() |
| } |
| |
| /// Removes all mappings whose keys have expired. |
| /// |
| /// *O*(*n*) time |
| pub fn remove_expired(&mut self) { |
| self.0.remove_expired() |
| } |
| |
| /// Reserves room for additional elements. |
| /// |
| /// *O*(*n*) time |
| pub fn reserve(&mut self, additional_capacity: usize) { |
| self.0.reserve(additional_capacity) |
| } |
| |
| /// Shrinks the capacity to the minimum allowed to hold the current number of elements. |
| /// |
| /// *O*(*n*) time |
| pub fn shrink_to_fit(&mut self) { |
| self.0.shrink_to_fit() |
| } |
| |
| /// Returns an over-approximation of the number of elements. |
| /// |
| /// *O*(1) time |
| pub fn len(&self) -> usize { |
| self.0.len() |
| } |
| |
| /// Is the set empty? |
| /// |
| /// Note that this may return false even if all keys in the set have |
| /// expired, if they haven't been collected yet. |
| /// |
| /// *O*(1) time |
| pub fn is_empty(&self) -> bool { |
| self.0.is_empty() |
| } |
| |
| /// The proportion of buckets that are used. |
| /// |
| /// This is an over-approximation because of expired elements. |
| /// |
| /// *O*(1) time |
| pub fn load_factor(&self) -> f32 { |
| self.0.load_factor() |
| } |
| |
| /// Removes all associations from the map. |
| /// |
| /// *O*(*n*) time |
| pub fn clear(&mut self) { |
| self.0.clear() |
| } |
| |
| // Non-ptr WeakHashSet should probably have `get` method. |
| |
| /// Returns true if the map contains the specified key. |
| /// |
| /// expected *O*(1) time; worst-case *O*(*p*) time |
| pub fn contains<Q>(&self, key: &Q) -> bool |
| where Q: ?Sized + Eq + Hash, |
| T::Key: Borrow<Q> |
| { |
| self.0.contains_key(key) |
| } |
| |
| /// Gets a strong reference to the given key, if found. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use weak_table::WeakHashSet; |
| /// use std::rc::{Rc, Weak}; |
| /// use std::ops::Deref; |
| /// |
| /// let mut set: WeakHashSet<Weak<String>> = WeakHashSet::new(); |
| /// |
| /// let a = Rc::new("a".to_owned()); |
| /// set.insert(a.clone()); |
| /// |
| /// let also_a = set.get("a").unwrap(); |
| /// |
| /// assert!(Rc::ptr_eq( &a, &also_a )); |
| /// ``` |
| /// |
| /// expected *O*(1) time; worst-case *O*(*p*) time |
| pub fn get<Q>(&self, key: &Q) -> Option<T::Strong> |
| where Q: ?Sized + Eq + Hash, |
| T::Key: Borrow<Q> |
| { |
| self.0.get_key(key) |
| } |
| |
| /// Unconditionally inserts the value, returning the old value if already present. Does not |
| /// replace the key. |
| /// |
| /// expected *O*(1) time; worst-case *O*(*p*) time |
| pub fn insert(&mut self, key: T::Strong) -> bool { |
| self.0.insert(key, ()).is_some() |
| } |
| |
| /// Removes the entry with the given key, if it exists, and returns the value. |
| /// |
| /// expected *O*(1) time; worst-case *O*(*p*) time |
| pub fn remove<Q>(&mut self, key: &Q) -> bool |
| where Q: ?Sized + Eq + Hash, |
| T::Key: Borrow<Q> |
| { |
| self.0.remove(key).is_some() |
| } |
| |
| /// Removes all mappings not satisfying the given predicate. |
| /// |
| /// Also removes any expired mappings. |
| /// |
| /// *O*(*n*) time |
| pub fn retain<F>(&mut self, mut f: F) |
| where F: FnMut(T::Strong) -> bool |
| { |
| self.0.retain(|k, _| f(k)) |
| } |
| |
| /// Is self a subset of other? |
| /// |
| /// expected *O*(*n*) time; worst-case *O*(*nq*) time (where *n* is |
| /// `self.capacity()` and *q* is the length of the probe sequences |
| /// in `other`) |
| pub fn is_subset<S1>(&self, other: &WeakHashSet<T, S1>) -> bool |
| where S1: BuildHasher |
| { |
| self.0.domain_is_subset(&other.0) |
| } |
| } |
| |
| /// An iterator over the elements of a set. |
| pub struct Iter<'a, T: 'a>(base::Keys<'a, T, ()>); |
| |
| impl<'a, T: WeakElement> Iterator for Iter<'a, T> { |
| type Item = T::Strong; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| self.0.next() |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.0.size_hint() |
| } |
| } |
| |
| /// An iterator over the elements of a set. |
| pub struct IntoIter<T>(base::IntoIter<T, ()>); |
| |
| impl<T: WeakElement> Iterator for IntoIter<T> { |
| type Item = T::Strong; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| self.0.next().map(|pair| pair.0) |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.0.size_hint() |
| } |
| } |
| |
| /// A draining iterator over the elements of a set. |
| pub struct Drain<'a, T: 'a>(base::Drain<'a, T, ()>); |
| |
| impl<'a, T: WeakElement> Iterator for Drain<'a, T> { |
| type Item = T::Strong; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| self.0.next().map(|pair| pair.0) |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.0.size_hint() |
| } |
| } |
| |
| impl<T: WeakKey, S> WeakHashSet<T, S> { |
| /// Gets an iterator over the keys and values. |
| /// |
| /// *O*(1) time |
| pub fn iter(&self) -> Iter<T> { |
| Iter(self.0.keys()) |
| } |
| |
| /// Gets a draining iterator, which removes all the values but retains the storage. |
| /// |
| /// *O*(1) time (and *O*(*n*) time to dispose of the result) |
| pub fn drain(&mut self) -> Drain<T> { |
| Drain(self.0.drain()) |
| } |
| } |
| |
| impl<T, S, S1> PartialEq<WeakHashSet<T, S1>> for WeakHashSet<T, S> |
| where T: WeakKey, |
| S: BuildHasher, |
| S1: BuildHasher |
| { |
| fn eq(&self, other: &WeakHashSet<T, S1>) -> bool { |
| self.0 == other.0 |
| } |
| } |
| |
| impl<T: WeakKey, S: BuildHasher> Eq for WeakHashSet<T, S> |
| where T::Key: Eq |
| { } |
| |
| impl<T: WeakKey, S: BuildHasher + Default> Default for WeakHashSet<T, S> { |
| fn default() -> Self { |
| WeakHashSet(base::WeakKeyHashMap::<T, (), S>::default()) |
| } |
| } |
| |
| impl<T, S> FromIterator<T::Strong> for WeakHashSet<T, S> |
| where T: WeakKey, |
| S: BuildHasher + Default |
| { |
| fn from_iter<I: IntoIterator<Item=T::Strong>>(iter: I) -> Self { |
| WeakHashSet(base::WeakKeyHashMap::<T, (), S>::from_iter( |
| iter.into_iter().map(|k| (k, ())))) |
| } |
| } |
| |
| impl<T: WeakKey, S: BuildHasher> Extend<T::Strong> for WeakHashSet<T, S> { |
| fn extend<I: IntoIterator<Item=T::Strong>>(&mut self, iter: I) { |
| self.0.extend(iter.into_iter().map(|k| (k, ()))) |
| } |
| } |
| |
| impl<T: WeakKey, S> Debug for WeakHashSet<T, S> |
| where T::Strong: Debug |
| { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| self.0.fmt(f) |
| } |
| } |
| |
| impl<T: WeakKey, S> IntoIterator for WeakHashSet<T, S> { |
| type Item = T::Strong; |
| type IntoIter = IntoIter<T>; |
| |
| /// Creates an owning iterator from `self`. |
| /// |
| /// *O*(1) time (and *O*(*n*) time to dispose of the result) |
| fn into_iter(self) -> Self::IntoIter { |
| IntoIter(self.0.into_iter()) |
| } |
| } |
| |
| impl<'a, T: WeakKey, S> IntoIterator for &'a WeakHashSet<T, S> { |
| type Item = T::Strong; |
| type IntoIter = Iter<'a, T>; |
| |
| /// Creates a borrowing iterator from `self`. |
| /// |
| /// *O*(1) time |
| fn into_iter(self) -> Self::IntoIter { |
| Iter(self.0.keys()) |
| } |
| } |