Auto merge of #54043 - fintelia:raw_entry, r=alexcrichton
Add raw_entry API to HashMap This is a continuation of #50821.
This commit is contained in:
bors
commit
e800988579
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@ -20,7 +20,7 @@ use fmt::{self, Debug};
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use hash::{Hash, Hasher, BuildHasher, SipHasher13};
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use iter::{FromIterator, FusedIterator};
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use mem::{self, replace};
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use ops::{Deref, Index};
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use ops::{Deref, DerefMut, Index};
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use sys;
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use super::table::{self, Bucket, EmptyBucket, Fallibility, FullBucket, FullBucketMut, RawTable,
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@ -435,12 +435,13 @@ fn search_hashed<K, V, M, F>(table: M, hash: SafeHash, is_match: F) -> InternalE
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return InternalEntry::TableIsEmpty;
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}
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search_hashed_nonempty(table, hash, is_match)
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search_hashed_nonempty(table, hash, is_match, true)
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}
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/// Search for a pre-hashed key when the hash map is known to be non-empty.
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#[inline]
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fn search_hashed_nonempty<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F)
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fn search_hashed_nonempty<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F,
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compare_hashes: bool)
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-> InternalEntry<K, V, M>
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where M: Deref<Target = RawTable<K, V>>,
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F: FnMut(&K) -> bool
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@ -476,7 +477,7 @@ fn search_hashed_nonempty<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F)
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}
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// If the hash doesn't match, it can't be this one..
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if hash == full.hash() {
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if !compare_hashes || hash == full.hash() {
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// If the key doesn't match, it can't be this one..
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if is_match(full.read().0) {
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return InternalEntry::Occupied { elem: full };
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@ -488,6 +489,57 @@ fn search_hashed_nonempty<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F)
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}
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}
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/// Same as `search_hashed_nonempty` but for mutable access.
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#[inline]
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fn search_hashed_nonempty_mut<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F,
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compare_hashes: bool)
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-> InternalEntry<K, V, M>
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where M: DerefMut<Target = RawTable<K, V>>,
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F: FnMut(&K) -> bool
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{
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// Do not check the capacity as an extra branch could slow the lookup.
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let size = table.size();
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let mut probe = Bucket::new(table, hash);
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let mut displacement = 0;
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loop {
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let mut full = match probe.peek() {
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Empty(bucket) => {
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// Found a hole!
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return InternalEntry::Vacant {
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hash,
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elem: NoElem(bucket, displacement),
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};
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}
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Full(bucket) => bucket,
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};
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let probe_displacement = full.displacement();
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if probe_displacement < displacement {
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// Found a luckier bucket than me.
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// We can finish the search early if we hit any bucket
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// with a lower distance to initial bucket than we've probed.
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return InternalEntry::Vacant {
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hash,
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elem: NeqElem(full, probe_displacement),
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};
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}
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// If the hash doesn't match, it can't be this one..
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if hash == full.hash() || !compare_hashes {
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// If the key doesn't match, it can't be this one..
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if is_match(full.read_mut().0) {
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return InternalEntry::Occupied { elem: full };
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}
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}
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displacement += 1;
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probe = full.next();
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debug_assert!(displacement <= size);
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}
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}
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fn pop_internal<K, V>(starting_bucket: FullBucketMut<K, V>)
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-> (K, V, &mut RawTable<K, V>)
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{
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@ -593,7 +645,7 @@ impl<K, V, S> HashMap<K, V, S>
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}
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let hash = self.make_hash(q);
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search_hashed_nonempty(&self.table, hash, |k| q.eq(k.borrow()))
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search_hashed_nonempty(&self.table, hash, |k| q.eq(k.borrow()), true)
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.into_occupied_bucket()
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}
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@ -608,7 +660,7 @@ impl<K, V, S> HashMap<K, V, S>
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}
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let hash = self.make_hash(q);
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search_hashed_nonempty(&mut self.table, hash, |k| q.eq(k.borrow()))
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search_hashed_nonempty(&mut self.table, hash, |k| q.eq(k.borrow()), true)
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.into_occupied_bucket()
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}
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@ -1484,6 +1536,68 @@ impl<K, V, S> HashMap<K, V, S>
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}
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}
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impl<K, V, S> HashMap<K, V, S>
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where K: Eq + Hash,
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S: BuildHasher
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{
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/// Creates a raw entry builder for the HashMap.
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///
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/// Raw entries provide the lowest level of control for searching and
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/// manipulating a map. They must be manually initialized with a hash and
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/// then manually searched. After this, insertions into a vacant entry
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/// still require an owned key to be provided.
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///
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/// Raw entries are useful for such exotic situations as:
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///
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/// * Hash memoization
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/// * Deferring the creation of an owned key until it is known to be required
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/// * Using a search key that doesn't work with the Borrow trait
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/// * Using custom comparison logic without newtype wrappers
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///
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/// Because raw entries provide much more low-level control, it's much easier
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/// to put the HashMap into an inconsistent state which, while memory-safe,
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/// will cause the map to produce seemingly random results. Higher-level and
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/// more foolproof APIs like `entry` should be preferred when possible.
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///
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/// In particular, the hash used to initialized the raw entry must still be
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/// consistent with the hash of the key that is ultimately stored in the entry.
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/// This is because implementations of HashMap may need to recompute hashes
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/// when resizing, at which point only the keys are available.
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///
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/// Raw entries give mutable access to the keys. This must not be used
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/// to modify how the key would compare or hash, as the map will not re-evaluate
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/// where the key should go, meaning the keys may become "lost" if their
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/// location does not reflect their state. For instance, if you change a key
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/// so that the map now contains keys which compare equal, search may start
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/// acting eratically, with two keys randomly masking eachother. Implementations
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/// are free to assume this doesn't happen (within the limits of memory-safety).
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn raw_entry_mut(&mut self) -> RawEntryBuilderMut<K, V, S> {
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self.reserve(1);
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RawEntryBuilderMut { map: self }
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}
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/// Creates a raw immutable entry builder for the HashMap.
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///
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/// Raw entries provide the lowest level of control for searching and
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/// manipulating a map. They must be manually initialized with a hash and
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/// then manually searched.
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///
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/// This is useful for
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/// * Hash memoization
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/// * Using a search key that doesn't work with the Borrow trait
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/// * Using custom comparison logic without newtype wrappers
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///
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/// Unless you are in such a situation, higher-level and more foolproof APIs like
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/// `get` should be preferred.
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///
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/// Immutable raw entries have very limited use; you might instead want `raw_entry_mut`.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn raw_entry(&self) -> RawEntryBuilder<K, V, S> {
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RawEntryBuilder { map: self }
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<K, V, S> PartialEq for HashMap<K, V, S>
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where K: Eq + Hash,
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@ -1724,6 +1838,456 @@ impl<'a, K, V> InternalEntry<K, V, &'a mut RawTable<K, V>> {
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}
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}
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/// A builder for computing where in a HashMap a key-value pair would be stored.
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///
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/// See the [`HashMap::raw_entry_mut`] docs for usage examples.
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///
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/// [`HashMap::raw_entry_mut`]: struct.HashMap.html#method.raw_entry_mut
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub struct RawEntryBuilderMut<'a, K: 'a, V: 'a, S: 'a> {
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map: &'a mut HashMap<K, V, S>,
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}
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/// A view into a single entry in a map, which may either be vacant or occupied.
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///
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/// This is a lower-level version of [`Entry`].
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///
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/// This `enum` is constructed from the [`raw_entry`] method on [`HashMap`].
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///
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/// [`HashMap`]: struct.HashMap.html
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/// [`Entry`]: enum.Entry.html
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/// [`raw_entry`]: struct.HashMap.html#method.raw_entry
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub enum RawEntryMut<'a, K: 'a, V: 'a, S: 'a> {
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/// An occupied entry.
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Occupied(RawOccupiedEntryMut<'a, K, V>),
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/// A vacant entry.
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Vacant(RawVacantEntryMut<'a, K, V, S>),
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}
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/// A view into an occupied entry in a `HashMap`.
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/// It is part of the [`RawEntryMut`] enum.
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///
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/// [`RawEntryMut`]: enum.RawEntryMut.html
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub struct RawOccupiedEntryMut<'a, K: 'a, V: 'a> {
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elem: FullBucket<K, V, &'a mut RawTable<K, V>>,
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}
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/// A view into a vacant entry in a `HashMap`.
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/// It is part of the [`RawEntryMut`] enum.
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///
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/// [`RawEntryMut`]: enum.RawEntryMut.html
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub struct RawVacantEntryMut<'a, K: 'a, V: 'a, S: 'a> {
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elem: VacantEntryState<K, V, &'a mut RawTable<K, V>>,
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hash_builder: &'a S,
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}
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/// A builder for computing where in a HashMap a key-value pair would be stored.
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///
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/// See the [`HashMap::raw_entry`] docs for usage examples.
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///
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/// [`HashMap::raw_entry`]: struct.HashMap.html#method.raw_entry
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub struct RawEntryBuilder<'a, K: 'a, V: 'a, S: 'a> {
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map: &'a HashMap<K, V, S>,
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}
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impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
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where S: BuildHasher,
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K: Eq + Hash,
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{
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/// Create a `RawEntryMut` from the given key.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn from_key<Q: ?Sized>(self, k: &Q) -> RawEntryMut<'a, K, V, S>
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where K: Borrow<Q>,
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Q: Hash + Eq
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{
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let mut hasher = self.map.hash_builder.build_hasher();
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k.hash(&mut hasher);
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self.from_key_hashed_nocheck(hasher.finish(), k)
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}
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/// Create a `RawEntryMut` from the given key and its hash.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn from_key_hashed_nocheck<Q: ?Sized>(self, hash: u64, k: &Q) -> RawEntryMut<'a, K, V, S>
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where K: Borrow<Q>,
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Q: Eq
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{
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self.from_hash(hash, |q| q.borrow().eq(k))
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}
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fn search<F>(self, hash: u64, is_match: F, compare_hashes: bool) -> RawEntryMut<'a, K, V, S>
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where for<'b> F: FnMut(&'b K) -> bool,
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{
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match search_hashed_nonempty_mut(&mut self.map.table,
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SafeHash::new(hash),
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is_match,
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compare_hashes) {
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InternalEntry::Occupied { elem } => {
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RawEntryMut::Occupied(RawOccupiedEntryMut { elem })
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}
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InternalEntry::Vacant { elem, .. } => {
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RawEntryMut::Vacant(RawVacantEntryMut {
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elem,
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hash_builder: &self.map.hash_builder,
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})
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}
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InternalEntry::TableIsEmpty => {
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unreachable!()
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}
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}
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}
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/// Create a `RawEntryMut` from the given hash.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn from_hash<F>(self, hash: u64, is_match: F) -> RawEntryMut<'a, K, V, S>
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where for<'b> F: FnMut(&'b K) -> bool,
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{
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self.search(hash, is_match, true)
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}
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/// Search possible locations for an element with hash `hash` until `is_match` returns true for
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/// one of them. There is no guarantee that all keys passed to `is_match` will have the provided
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/// hash.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn search_bucket<F>(self, hash: u64, is_match: F) -> RawEntryMut<'a, K, V, S>
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where for<'b> F: FnMut(&'b K) -> bool,
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{
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self.search(hash, is_match, false)
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}
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}
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impl<'a, K, V, S> RawEntryBuilder<'a, K, V, S>
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where S: BuildHasher,
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{
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/// Access an entry by key.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn from_key<Q: ?Sized>(self, k: &Q) -> Option<(&'a K, &'a V)>
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where K: Borrow<Q>,
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Q: Hash + Eq
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{
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let mut hasher = self.map.hash_builder.build_hasher();
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k.hash(&mut hasher);
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self.from_key_hashed_nocheck(hasher.finish(), k)
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}
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/// Access an entry by a key and its hash.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn from_key_hashed_nocheck<Q: ?Sized>(self, hash: u64, k: &Q) -> Option<(&'a K, &'a V)>
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where K: Borrow<Q>,
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Q: Hash + Eq
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{
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self.from_hash(hash, |q| q.borrow().eq(k))
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}
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fn search<F>(self, hash: u64, is_match: F, compare_hashes: bool) -> Option<(&'a K, &'a V)>
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where F: FnMut(&K) -> bool
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{
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match search_hashed_nonempty(&self.map.table,
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SafeHash::new(hash),
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is_match,
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compare_hashes) {
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InternalEntry::Occupied { elem } => Some(elem.into_refs()),
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InternalEntry::Vacant { .. } => None,
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InternalEntry::TableIsEmpty => unreachable!(),
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}
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}
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/// Access an entry by hash.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn from_hash<F>(self, hash: u64, is_match: F) -> Option<(&'a K, &'a V)>
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where F: FnMut(&K) -> bool
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{
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self.search(hash, is_match, true)
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}
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/// Search possible locations for an element with hash `hash` until `is_match` returns true for
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/// one of them. There is no guarantee that all keys passed to `is_match` will have the provided
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/// hash.
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn search_bucket<F>(self, hash: u64, is_match: F) -> Option<(&'a K, &'a V)>
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where F: FnMut(&K) -> bool
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{
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self.search(hash, is_match, false)
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}
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}
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impl<'a, K, V, S> RawEntryMut<'a, K, V, S> {
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/// Ensures a value is in the entry by inserting the default if empty, and returns
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/// mutable references to the key and value in the entry.
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///
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/// # Examples
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///
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/// ```
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/// #![feature(hash_raw_entry)]
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/// use std::collections::HashMap;
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///
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/// let mut map: HashMap<&str, u32> = HashMap::new();
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/// map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 12);
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///
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/// assert_eq!(map["poneyland"], 12);
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///
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/// *map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 12).1 += 10;
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/// assert_eq!(map["poneyland"], 22);
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/// ```
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn or_insert(self, default_key: K, default_val: V) -> (&'a mut K, &'a mut V)
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where K: Hash,
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S: BuildHasher,
|
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{
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match self {
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RawEntryMut::Occupied(entry) => entry.into_key_value(),
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RawEntryMut::Vacant(entry) => entry.insert(default_key, default_val),
|
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}
|
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}
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/// Ensures a value is in the entry by inserting the result of the default function if empty,
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/// and returns mutable references to the key and value in the entry.
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///
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/// # Examples
|
||||
///
|
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/// ```
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/// #![feature(hash_raw_entry)]
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/// use std::collections::HashMap;
|
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///
|
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/// let mut map: HashMap<&str, String> = HashMap::new();
|
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///
|
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/// map.raw_entry_mut().from_key("poneyland").or_insert_with(|| {
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/// ("poneyland", "hoho".to_string())
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/// });
|
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///
|
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/// assert_eq!(map["poneyland"], "hoho".to_string());
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/// ```
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#[unstable(feature = "hash_raw_entry", issue = "54043")]
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pub fn or_insert_with<F>(self, default: F) -> (&'a mut K, &'a mut V)
|
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where F: FnOnce() -> (K, V),
|
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K: Hash,
|
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S: BuildHasher,
|
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{
|
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match self {
|
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RawEntryMut::Occupied(entry) => entry.into_key_value(),
|
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RawEntryMut::Vacant(entry) => {
|
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let (k, v) = default();
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entry.insert(k, v)
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||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Provides in-place mutable access to an occupied entry before any
|
||||
/// potential inserts into the map.
|
||||
///
|
||||
/// # Examples
|
||||
///
|
||||
/// ```
|
||||
/// #![feature(hash_raw_entry)]
|
||||
/// use std::collections::HashMap;
|
||||
///
|
||||
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
||||
///
|
||||
/// map.raw_entry_mut()
|
||||
/// .from_key("poneyland")
|
||||
/// .and_modify(|_k, v| { *v += 1 })
|
||||
/// .or_insert("poneyland", 42);
|
||||
/// assert_eq!(map["poneyland"], 42);
|
||||
///
|
||||
/// map.raw_entry_mut()
|
||||
/// .from_key("poneyland")
|
||||
/// .and_modify(|_k, v| { *v += 1 })
|
||||
/// .or_insert("poneyland", 0);
|
||||
/// assert_eq!(map["poneyland"], 43);
|
||||
/// ```
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn and_modify<F>(self, f: F) -> Self
|
||||
where F: FnOnce(&mut K, &mut V)
|
||||
{
|
||||
match self {
|
||||
RawEntryMut::Occupied(mut entry) => {
|
||||
{
|
||||
let (k, v) = entry.get_key_value_mut();
|
||||
f(k, v);
|
||||
}
|
||||
RawEntryMut::Occupied(entry)
|
||||
},
|
||||
RawEntryMut::Vacant(entry) => RawEntryMut::Vacant(entry),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a, K, V> RawOccupiedEntryMut<'a, K, V> {
|
||||
/// Gets a reference to the key in the entry.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn key(&self) -> &K {
|
||||
self.elem.read().0
|
||||
}
|
||||
|
||||
/// Gets a mutable reference to the key in the entry.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn key_mut(&mut self) -> &mut K {
|
||||
self.elem.read_mut().0
|
||||
}
|
||||
|
||||
/// Converts the entry into a mutable reference to the key in the entry
|
||||
/// with a lifetime bound to the map itself.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn into_key(self) -> &'a mut K {
|
||||
self.elem.into_mut_refs().0
|
||||
}
|
||||
|
||||
/// Gets a reference to the value in the entry.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn get(&self) -> &V {
|
||||
self.elem.read().1
|
||||
}
|
||||
|
||||
/// Converts the OccupiedEntry into a mutable reference to the value in the entry
|
||||
/// with a lifetime bound to the map itself.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn into_mut(self) -> &'a mut V {
|
||||
self.elem.into_mut_refs().1
|
||||
}
|
||||
|
||||
/// Gets a mutable reference to the value in the entry.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn get_mut(&mut self) -> &mut V {
|
||||
self.elem.read_mut().1
|
||||
}
|
||||
|
||||
/// Gets a reference to the key and value in the entry.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn get_key_value(&mut self) -> (&K, &V) {
|
||||
self.elem.read()
|
||||
}
|
||||
|
||||
/// Gets a mutable reference to the key and value in the entry.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn get_key_value_mut(&mut self) -> (&mut K, &mut V) {
|
||||
self.elem.read_mut()
|
||||
}
|
||||
|
||||
/// Converts the OccupiedEntry into a mutable reference to the key and value in the entry
|
||||
/// with a lifetime bound to the map itself.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn into_key_value(self) -> (&'a mut K, &'a mut V) {
|
||||
self.elem.into_mut_refs()
|
||||
}
|
||||
|
||||
/// Sets the value of the entry, and returns the entry's old value.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn insert(&mut self, value: V) -> V {
|
||||
mem::replace(self.get_mut(), value)
|
||||
}
|
||||
|
||||
/// Sets the value of the entry, and returns the entry's old value.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn insert_key(&mut self, key: K) -> K {
|
||||
mem::replace(self.key_mut(), key)
|
||||
}
|
||||
|
||||
/// Takes the value out of the entry, and returns it.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn remove(self) -> V {
|
||||
pop_internal(self.elem).1
|
||||
}
|
||||
|
||||
/// Take the ownership of the key and value from the map.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn remove_entry(self) -> (K, V) {
|
||||
let (k, v, _) = pop_internal(self.elem);
|
||||
(k, v)
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a, K, V, S> RawVacantEntryMut<'a, K, V, S> {
|
||||
/// Sets the value of the entry with the VacantEntry's key,
|
||||
/// and returns a mutable reference to it.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn insert(self, key: K, value: V) -> (&'a mut K, &'a mut V)
|
||||
where K: Hash,
|
||||
S: BuildHasher,
|
||||
{
|
||||
let mut hasher = self.hash_builder.build_hasher();
|
||||
key.hash(&mut hasher);
|
||||
self.insert_hashed_nocheck(hasher.finish(), key, value)
|
||||
}
|
||||
|
||||
/// Sets the value of the entry with the VacantEntry's key,
|
||||
/// and returns a mutable reference to it.
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
pub fn insert_hashed_nocheck(self, hash: u64, key: K, value: V) -> (&'a mut K, &'a mut V) {
|
||||
let hash = SafeHash::new(hash);
|
||||
let b = match self.elem {
|
||||
NeqElem(mut bucket, disp) => {
|
||||
if disp >= DISPLACEMENT_THRESHOLD {
|
||||
bucket.table_mut().set_tag(true);
|
||||
}
|
||||
robin_hood(bucket, disp, hash, key, value)
|
||||
},
|
||||
NoElem(mut bucket, disp) => {
|
||||
if disp >= DISPLACEMENT_THRESHOLD {
|
||||
bucket.table_mut().set_tag(true);
|
||||
}
|
||||
bucket.put(hash, key, value)
|
||||
},
|
||||
};
|
||||
b.into_mut_refs()
|
||||
}
|
||||
}
|
||||
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
impl<'a, K, V, S> Debug for RawEntryBuilderMut<'a, K, V, S> {
|
||||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||||
f.debug_struct("RawEntryBuilder")
|
||||
.finish()
|
||||
}
|
||||
}
|
||||
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
impl<'a, K: Debug, V: Debug, S> Debug for RawEntryMut<'a, K, V, S> {
|
||||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||||
match *self {
|
||||
RawEntryMut::Vacant(ref v) => {
|
||||
f.debug_tuple("RawEntry")
|
||||
.field(v)
|
||||
.finish()
|
||||
}
|
||||
RawEntryMut::Occupied(ref o) => {
|
||||
f.debug_tuple("RawEntry")
|
||||
.field(o)
|
||||
.finish()
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
impl<'a, K: Debug, V: Debug> Debug for RawOccupiedEntryMut<'a, K, V> {
|
||||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||||
f.debug_struct("RawOccupiedEntryMut")
|
||||
.field("key", self.key())
|
||||
.field("value", self.get())
|
||||
.finish()
|
||||
}
|
||||
}
|
||||
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
impl<'a, K, V, S> Debug for RawVacantEntryMut<'a, K, V, S> {
|
||||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||||
f.debug_struct("RawVacantEntryMut")
|
||||
.finish()
|
||||
}
|
||||
}
|
||||
|
||||
#[unstable(feature = "hash_raw_entry", issue = "54043")]
|
||||
impl<'a, K, V, S> Debug for RawEntryBuilder<'a, K, V, S> {
|
||||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||||
f.debug_struct("RawEntryBuilder")
|
||||
.finish()
|
||||
}
|
||||
}
|
||||
|
||||
/// A view into a single entry in a map, which may either be vacant or occupied.
|
||||
///
|
||||
/// This `enum` is constructed from the [`entry`] method on [`HashMap`].
|
||||
|
|
@ -3681,4 +4245,106 @@ mod test_map {
|
|||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_raw_entry() {
|
||||
use super::RawEntryMut::{Occupied, Vacant};
|
||||
|
||||
let xs = [(1i32, 10i32), (2, 20), (3, 30), (4, 40), (5, 50), (6, 60)];
|
||||
|
||||
let mut map: HashMap<_, _> = xs.iter().cloned().collect();
|
||||
|
||||
let compute_hash = |map: &HashMap<i32, i32>, k: i32| -> u64 {
|
||||
use core::hash::{BuildHasher, Hash, Hasher};
|
||||
|
||||
let mut hasher = map.hasher().build_hasher();
|
||||
k.hash(&mut hasher);
|
||||
hasher.finish()
|
||||
};
|
||||
|
||||
// Existing key (insert)
|
||||
match map.raw_entry_mut().from_key(&1) {
|
||||
Vacant(_) => unreachable!(),
|
||||
Occupied(mut view) => {
|
||||
assert_eq!(view.get(), &10);
|
||||
assert_eq!(view.insert(100), 10);
|
||||
}
|
||||
}
|
||||
let hash1 = compute_hash(&map, 1);
|
||||
assert_eq!(map.raw_entry().from_key(&1).unwrap(), (&1, &100));
|
||||
assert_eq!(map.raw_entry().from_hash(hash1, |k| *k == 1).unwrap(), (&1, &100));
|
||||
assert_eq!(map.raw_entry().from_key_hashed_nocheck(hash1, &1).unwrap(), (&1, &100));
|
||||
assert_eq!(map.raw_entry().search_bucket(hash1, |k| *k == 1).unwrap(), (&1, &100));
|
||||
assert_eq!(map.len(), 6);
|
||||
|
||||
// Existing key (update)
|
||||
match map.raw_entry_mut().from_key(&2) {
|
||||
Vacant(_) => unreachable!(),
|
||||
Occupied(mut view) => {
|
||||
let v = view.get_mut();
|
||||
let new_v = (*v) * 10;
|
||||
*v = new_v;
|
||||
}
|
||||
}
|
||||
let hash2 = compute_hash(&map, 2);
|
||||
assert_eq!(map.raw_entry().from_key(&2).unwrap(), (&2, &200));
|
||||
assert_eq!(map.raw_entry().from_hash(hash2, |k| *k == 2).unwrap(), (&2, &200));
|
||||
assert_eq!(map.raw_entry().from_key_hashed_nocheck(hash2, &2).unwrap(), (&2, &200));
|
||||
assert_eq!(map.raw_entry().search_bucket(hash2, |k| *k == 2).unwrap(), (&2, &200));
|
||||
assert_eq!(map.len(), 6);
|
||||
|
||||
// Existing key (take)
|
||||
let hash3 = compute_hash(&map, 3);
|
||||
match map.raw_entry_mut().from_key_hashed_nocheck(hash3, &3) {
|
||||
Vacant(_) => unreachable!(),
|
||||
Occupied(view) => {
|
||||
assert_eq!(view.remove_entry(), (3, 30));
|
||||
}
|
||||
}
|
||||
assert_eq!(map.raw_entry().from_key(&3), None);
|
||||
assert_eq!(map.raw_entry().from_hash(hash3, |k| *k == 3), None);
|
||||
assert_eq!(map.raw_entry().from_key_hashed_nocheck(hash3, &3), None);
|
||||
assert_eq!(map.raw_entry().search_bucket(hash3, |k| *k == 3), None);
|
||||
assert_eq!(map.len(), 5);
|
||||
|
||||
|
||||
// Nonexistent key (insert)
|
||||
match map.raw_entry_mut().from_key(&10) {
|
||||
Occupied(_) => unreachable!(),
|
||||
Vacant(view) => {
|
||||
assert_eq!(view.insert(10, 1000), (&mut 10, &mut 1000));
|
||||
}
|
||||
}
|
||||
assert_eq!(map.raw_entry().from_key(&10).unwrap(), (&10, &1000));
|
||||
assert_eq!(map.len(), 6);
|
||||
|
||||
// Ensure all lookup methods produce equivalent results.
|
||||
for k in 0..12 {
|
||||
let hash = compute_hash(&map, k);
|
||||
let v = map.get(&k).cloned();
|
||||
let kv = v.as_ref().map(|v| (&k, v));
|
||||
|
||||
assert_eq!(map.raw_entry().from_key(&k), kv);
|
||||
assert_eq!(map.raw_entry().from_hash(hash, |q| *q == k), kv);
|
||||
assert_eq!(map.raw_entry().from_key_hashed_nocheck(hash, &k), kv);
|
||||
assert_eq!(map.raw_entry().search_bucket(hash, |q| *q == k), kv);
|
||||
|
||||
match map.raw_entry_mut().from_key(&k) {
|
||||
Occupied(mut o) => assert_eq!(Some(o.get_key_value()), kv),
|
||||
Vacant(_) => assert_eq!(v, None),
|
||||
}
|
||||
match map.raw_entry_mut().from_key_hashed_nocheck(hash, &k) {
|
||||
Occupied(mut o) => assert_eq!(Some(o.get_key_value()), kv),
|
||||
Vacant(_) => assert_eq!(v, None),
|
||||
}
|
||||
match map.raw_entry_mut().from_hash(hash, |q| *q == k) {
|
||||
Occupied(mut o) => assert_eq!(Some(o.get_key_value()), kv),
|
||||
Vacant(_) => assert_eq!(v, None),
|
||||
}
|
||||
match map.raw_entry_mut().search_bucket(hash, |q| *q == k) {
|
||||
Occupied(mut o) => assert_eq!(Some(o.get_key_value()), kv),
|
||||
Vacant(_) => assert_eq!(v, None),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
|
|
|||
|
|
@ -283,6 +283,7 @@
|
|||
#![feature(prelude_import)]
|
||||
#![feature(ptr_internals)]
|
||||
#![feature(raw)]
|
||||
#![feature(hash_raw_entry)]
|
||||
#![feature(rustc_attrs)]
|
||||
#![feature(rustc_const_unstable)]
|
||||
#![feature(std_internals)]
|
||||
|
|
|
|||
Loading…
Reference in New Issue