From f79eea106c5d05e706ccd101dee0606f384e224f Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Wed, 13 Nov 2024 11:29:32 -0800
Subject: [PATCH] btree: simplify the backdoor between set and map
The internal `btree::Recover` trait acted as a private API between
`BTreeSet` and `BTreeMap`, but we can use `pub(_)` restrictions these
days, and some of the methods don't need special handling anymore.
* `BTreeSet::get` can use `BTreeMap::get_key_value`
* `BTreeSet::take` can use `BTreeMap::remove_entry`
* `BTreeSet::replace` does need help, but this now uses a `pub(super)`
method on `BTreeMap` instead of the trait.
* `btree::Recover` is now removed.
---
library/alloc/src/collections/btree/map.rs | 40 +++----------------
library/alloc/src/collections/btree/mod.rs | 8 ----
library/alloc/src/collections/btree/set.rs | 7 ++--
.../alloc/src/collections/btree/set_val.rs | 4 +-
4 files changed, 11 insertions(+), 48 deletions(-)
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index 55649d865fc63..66353ccfa47d3 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -289,40 +289,12 @@ impl<K: Clone, V: Clone, A: Allocator + Clone> Clone for BTreeMap<K, V, A> {
}
}
-impl<K, Q: ?Sized, A: Allocator + Clone> super::Recover<Q> for BTreeMap<K, SetValZST, A>
-where
- K: Borrow<Q> + Ord,
- Q: Ord,
-{
- type Key = K;
-
- fn get(&self, key: &Q) -> Option<&K> {
- let root_node = self.root.as_ref()?.reborrow();
- match root_node.search_tree(key) {
- Found(handle) => Some(handle.into_kv().0),
- GoDown(_) => None,
- }
- }
-
- fn take(&mut self, key: &Q) -> Option<K> {
- let (map, dormant_map) = DormantMutRef::new(self);
- let root_node = map.root.as_mut()?.borrow_mut();
- match root_node.search_tree(key) {
- Found(handle) => Some(
- OccupiedEntry {
- handle,
- dormant_map,
- alloc: (*map.alloc).clone(),
- _marker: PhantomData,
- }
- .remove_kv()
- .0,
- ),
- GoDown(_) => None,
- }
- }
-
- fn replace(&mut self, key: K) -> Option<K> {
+/// Internal functionality for `BTreeSet`.
+impl<K, A: Allocator + Clone> BTreeMap<K, SetValZST, A> {
+ pub(super) fn replace(&mut self, key: K) -> Option<K>
+ where
+ K: Ord,
+ {
let (map, dormant_map) = DormantMutRef::new(self);
let root_node =
map.root.get_or_insert_with(|| Root::new((*map.alloc).clone())).borrow_mut();
diff --git a/library/alloc/src/collections/btree/mod.rs b/library/alloc/src/collections/btree/mod.rs
index c7d0144de30cb..b8667d09c33b3 100644
--- a/library/alloc/src/collections/btree/mod.rs
+++ b/library/alloc/src/collections/btree/mod.rs
@@ -12,11 +12,3 @@ mod search;
pub mod set;
mod set_val;
mod split;
-
-trait Recover<Q: ?Sized> {
- type Key;
-
- fn get(&self, key: &Q) -> Option<&Self::Key>;
- fn take(&mut self, key: &Q) -> Option<Self::Key>;
- fn replace(&mut self, key: Self::Key) -> Option<Self::Key>;
-}
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index a40209fa2e397..8daee6030c270 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -7,7 +7,6 @@ use core::iter::{FusedIterator, Peekable};
use core::mem::ManuallyDrop;
use core::ops::{BitAnd, BitOr, BitXor, Bound, RangeBounds, Sub};
-use super::Recover;
use super::map::{BTreeMap, Keys};
use super::merge_iter::MergeIterInner;
use super::set_val::SetValZST;
@@ -635,7 +634,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
T: Borrow<Q> + Ord,
Q: Ord,
{
- Recover::get(&self.map, value)
+ self.map.get_key_value(value).map(|(k, _)| k)
}
/// Returns `true` if `self` has no elements in common with `other`.
@@ -926,7 +925,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
where
T: Ord,
{
- Recover::replace(&mut self.map, value)
+ self.map.replace(value)
}
/// If the set contains an element equal to the value, removes it from the
@@ -978,7 +977,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
T: Borrow<Q> + Ord,
Q: Ord,
{
- Recover::take(&mut self.map, value)
+ self.map.remove_entry(value).map(|(k, _)| k)
}
/// Retains only the elements specified by the predicate.
diff --git a/library/alloc/src/collections/btree/set_val.rs b/library/alloc/src/collections/btree/set_val.rs
index 80c459bcf81db..cf30160bfbbc2 100644
--- a/library/alloc/src/collections/btree/set_val.rs
+++ b/library/alloc/src/collections/btree/set_val.rs
@@ -3,14 +3,14 @@
/// * `BTreeMap<T, ()>` (possible user-defined map)
/// * `BTreeMap<T, SetValZST>` (internal set representation)
#[derive(Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Clone, Default)]
-pub struct SetValZST;
+pub(super) struct SetValZST;
/// A trait to differentiate between `BTreeMap` and `BTreeSet` values.
/// Returns `true` only for type `SetValZST`, `false` for all other types (blanket implementation).
/// `TypeId` requires a `'static` lifetime, use of this trait avoids that restriction.
///
/// [`TypeId`]: std::any::TypeId
-pub trait IsSetVal {
+pub(super) trait IsSetVal {
fn is_set_val() -> bool;
}