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Auto merge of #78104 - ssomers:btree_root_redux, r=Mark-Simulacrum

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BTreeMap: replace Root with NodeRef<Owned, ...>

`NodeRef<marker::Owned, …>` already exists as a representation of root nodes, and it makes more sense to alias `Root` to that than to reuse the space-efficient `BoxedNode` that is oblivious to height, where height is required.

r? `@Mark-Simulacrum`
This commit is contained in:
bors 2020-11-20 16:12:35 +00:00
commit 593fe977a7
9 changed files with 171 additions and 179 deletions
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4
library/alloc/src/collections/btree/append.rs
View File

@ -34,7 +34,7 @@ impl<K, V> Root<K, V> {
where
I: Iterator<Item = (K, V)>,
{
let mut cur_node = self.node_as_mut().last_leaf_edge().into_node();
let mut cur_node = self.borrow_mut().last_leaf_edge().into_node();
// Iterate through all key-value pairs, pushing them into nodes at the right level.
for (key, value) in iter {
// Try to push key-value pair into the current leaf node.
@ -86,7 +86,7 @@ impl<K, V> Root<K, V> {
fn fix_right_edge(&mut self) {
// Handle underfull nodes, start from the top.
let mut cur_node = self.node_as_mut();
let mut cur_node = self.borrow_mut();
while let Internal(internal) = cur_node.force() {
// Check if right-most child is underfull.
let mut last_kv = internal.last_kv().consider_for_balancing();

44
library/alloc/src/collections/btree/map.rs
View File

@ -157,7 +157,7 @@ impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> {
{
let root = out_tree.root.as_mut().unwrap(); // unwrap succeeds because we just wrapped
let mut out_node = match root.node_as_mut().force() {
let mut out_node = match root.borrow_mut().force() {
Leaf(leaf) => leaf,
Internal(_) => unreachable!(),
};
@ -213,7 +213,7 @@ impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> {
// Ord` constraint, which this method lacks.
BTreeMap { root: None, length: 0 }
} else {
clone_subtree(self.root.as_ref().unwrap().node_as_ref()) // unwrap succeeds because not empty
clone_subtree(self.root.as_ref().unwrap().reborrow()) // unwrap succeeds because not empty
}
}
}
@ -226,7 +226,7 @@ where
type Key = K;
fn get(&self, key: &Q) -> Option<&K> {
let root_node = self.root.as_ref()?.node_as_ref();
let root_node = self.root.as_ref()?.reborrow();
match search::search_tree(root_node, key) {
Found(handle) => Some(handle.into_kv().0),
GoDown(_) => None,
@ -235,7 +235,7 @@ where
fn take(&mut self, key: &Q) -> Option<K> {
let (map, dormant_map) = DormantMutRef::new(self);
let root_node = map.root.as_mut()?.node_as_mut();
let root_node = map.root.as_mut()?.borrow_mut();
match search::search_tree(root_node, key) {
Found(handle) => {
Some(OccupiedEntry { handle, dormant_map, _marker: PhantomData }.remove_kv().0)
@ -246,7 +246,7 @@ where
fn replace(&mut self, key: K) -> Option<K> {
let (map, dormant_map) = DormantMutRef::new(self);
let root_node = Self::ensure_is_owned(&mut map.root).node_as_mut();
let root_node = Self::ensure_is_owned(&mut map.root).borrow_mut();
match search::search_tree::<marker::Mut<'_>, K, (), K>(root_node, &key) {
Found(handle) => Some(mem::replace(handle.into_key_mut(), key)),
GoDown(handle) => {
@ -522,7 +522,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
K: Borrow<Q>,
Q: Ord,
{
let root_node = self.root.as_ref()?.node_as_ref();
let root_node = self.root.as_ref()?.reborrow();
match search::search_tree(root_node, key) {
Found(handle) => Some(handle.into_kv().1),
GoDown(_) => None,
@ -550,7 +550,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
K: Borrow<Q>,
Q: Ord,
{
let root_node = self.root.as_ref()?.node_as_ref();
let root_node = self.root.as_ref()?.reborrow();
match search::search_tree(root_node, k) {
Found(handle) => Some(handle.into_kv()),
GoDown(_) => None,
@ -576,7 +576,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
/// ```
#[unstable(feature = "map_first_last", issue = "62924")]
pub fn first_key_value(&self) -> Option<(&K, &V)> {
let root_node = self.root.as_ref()?.node_as_ref();
let root_node = self.root.as_ref()?.reborrow();
root_node.first_leaf_edge().right_kv().ok().map(Handle::into_kv)
}
@ -603,7 +603,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
#[unstable(feature = "map_first_last", issue = "62924")]
pub fn first_entry(&mut self) -> Option<OccupiedEntry<'_, K, V>> {
let (map, dormant_map) = DormantMutRef::new(self);
let root_node = map.root.as_mut()?.node_as_mut();
let root_node = map.root.as_mut()?.borrow_mut();
let kv = root_node.first_leaf_edge().right_kv().ok()?;
Some(OccupiedEntry { handle: kv.forget_node_type(), dormant_map, _marker: PhantomData })
}
@ -650,7 +650,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
/// ```
#[unstable(feature = "map_first_last", issue = "62924")]
pub fn last_key_value(&self) -> Option<(&K, &V)> {
let root_node = self.root.as_ref()?.node_as_ref();
let root_node = self.root.as_ref()?.reborrow();
root_node.last_leaf_edge().left_kv().ok().map(Handle::into_kv)
}
@ -677,7 +677,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
#[unstable(feature = "map_first_last", issue = "62924")]
pub fn last_entry(&mut self) -> Option<OccupiedEntry<'_, K, V>> {
let (map, dormant_map) = DormantMutRef::new(self);
let root_node = map.root.as_mut()?.node_as_mut();
let root_node = map.root.as_mut()?.borrow_mut();
let kv = root_node.last_leaf_edge().left_kv().ok()?;
Some(OccupiedEntry { handle: kv.forget_node_type(), dormant_map, _marker: PhantomData })
}
@ -758,7 +758,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
K: Borrow<Q>,
Q: Ord,
{
let root_node = self.root.as_mut()?.node_as_mut();
let root_node = self.root.as_mut()?.borrow_mut();
match search::search_tree(root_node, key) {
Found(handle) => Some(handle.into_val_mut()),
GoDown(_) => None,
@ -854,7 +854,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
Q: Ord,
{
let (map, dormant_map) = DormantMutRef::new(self);
let root_node = map.root.as_mut()?.node_as_mut();
let root_node = map.root.as_mut()?.borrow_mut();
match search::search_tree(root_node, key) {
Found(handle) => {
Some(OccupiedEntry { handle, dormant_map, _marker: PhantomData }.remove_entry())
@ -971,7 +971,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
R: RangeBounds<T>,
{
if let Some(root) = &self.root {
let (f, b) = root.node_as_ref().range_search(range);
let (f, b) = root.reborrow().range_search(range);
Range { front: Some(f), back: Some(b) }
} else {
@ -1017,7 +1017,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
R: RangeBounds<T>,
{
if let Some(root) = &mut self.root {
let (f, b) = root.node_as_valmut().range_search(range);
let (f, b) = root.borrow_valmut().range_search(range);
RangeMut { front: Some(f), back: Some(b), _marker: PhantomData }
} else {
@ -1047,7 +1047,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
pub fn entry(&mut self, key: K) -> Entry<'_, K, V> {
// FIXME(@porglezomp) Avoid allocating if we don't insert
let (map, dormant_map) = DormantMutRef::new(self);
let root_node = Self::ensure_is_owned(&mut map.root).node_as_mut();
let root_node = Self::ensure_is_owned(&mut map.root).borrow_mut();
match search::search_tree(root_node, &key) {
Found(handle) => Occupied(OccupiedEntry { handle, dormant_map, _marker: PhantomData }),
GoDown(handle) => {
@ -1103,10 +1103,10 @@ impl<K: Ord, V> BTreeMap<K, V> {
left_root.split_off(right_root, key);
if left_root.height() < right_root.height() {
self.length = left_root.node_as_ref().calc_length();
self.length = left_root.reborrow().calc_length();
right.length = total_num - self.len();
} else {
right.length = right_root.node_as_ref().calc_length();
right.length = right_root.reborrow().calc_length();
self.length = total_num - right.len();
}
@ -1154,7 +1154,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
pub(super) fn drain_filter_inner(&mut self) -> DrainFilterInner<'_, K, V> {
if let Some(root) = self.root.as_mut() {
let (root, dormant_root) = DormantMutRef::new(root);
let front = root.node_as_mut().first_leaf_edge();
let front = root.borrow_mut().first_leaf_edge();
DrainFilterInner {
length: &mut self.length,
dormant_root: Some(dormant_root),
@ -1361,7 +1361,7 @@ impl<K, V> IntoIterator for BTreeMap<K, V> {
fn into_iter(self) -> IntoIter<K, V> {
let mut me = ManuallyDrop::new(self);
if let Some(root) = me.root.take() {
let (f, b) = root.into_ref().full_range();
let (f, b) = root.full_range();
IntoIter { front: Some(f), back: Some(b), length: me.length }
} else {
@ -2007,7 +2007,7 @@ impl<K, V> BTreeMap<K, V> {
#[stable(feature = "rust1", since = "1.0.0")]
pub fn iter(&self) -> Iter<'_, K, V> {
if let Some(root) = &self.root {
let (f, b) = root.node_as_ref().full_range();
let (f, b) = root.reborrow().full_range();
Iter { range: Range { front: Some(f), back: Some(b) }, length: self.length }
} else {
@ -2039,7 +2039,7 @@ impl<K, V> BTreeMap<K, V> {
#[stable(feature = "rust1", since = "1.0.0")]
pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
if let Some(root) = &mut self.root {
let (f, b) = root.node_as_valmut().full_range();
let (f, b) = root.borrow_valmut().full_range();
IterMut {
range: RangeMut { front: Some(f), back: Some(b), _marker: PhantomData },

2
library/alloc/src/collections/btree/map/entry.rs
View File

@ -286,7 +286,7 @@ impl<'a, K: Ord, V> VacantEntry<'a, K, V> {
// Safety: We have consumed self.handle and the reference returned.
let map = unsafe { self.dormant_map.awaken() };
let root = map.root.as_mut().unwrap();
root.push_internal_level().push(ins.k, ins.v, ins.right);
root.push_internal_level().push(ins.kv.0, ins.kv.1, ins.right);
map.length += 1;
val_ptr
}

4
library/alloc/src/collections/btree/map/tests.rs
View File

@ -49,7 +49,7 @@ impl<K, V> BTreeMap<K, V> {
// Panics if the map (or the code navigating it) is corrupted.
fn check_invariants(&self) {
if let Some(root) = &self.root {
let root_node = root.node_as_ref();
let root_node = root.reborrow();
// Check the back pointers top-down, before we attempt to rely on
// more serious navigation code.
@ -92,7 +92,7 @@ impl<K, V> BTreeMap<K, V> {
K: Debug,
{
if let Some(root) = self.root.as_ref() {
root.node_as_ref().dump_keys()
root.reborrow().dump_keys()
} else {
String::from("not yet allocated")
}

198
library/alloc/src/collections/btree/node.rs
View File

@ -31,7 +31,7 @@
use core::cmp::Ordering;
use core::marker::PhantomData;
use core::mem::{self, MaybeUninit};
use core::ptr::{self, NonNull, Unique};
use core::ptr::{self, NonNull};
use crate::alloc::{AllocRef, Global, Layout};
use crate::boxed::Box;
@ -114,100 +114,80 @@ impl<K, V> InternalNode<K, V> {
/// of nodes it actually contains, and, partially due to this lack of information,
/// has no destructor.
struct BoxedNode<K, V> {
ptr: Unique<LeafNode<K, V>>,
ptr: NonNull<LeafNode<K, V>>,
}
impl<K, V> BoxedNode<K, V> {
fn from_leaf(node: Box<LeafNode<K, V>>) -> Self {
BoxedNode { ptr: Unique::from(Box::leak(node)) }
}
fn from_internal(node: Box<InternalNode<K, V>>) -> Self {
BoxedNode { ptr: Unique::from(Box::leak(node)).cast() }
fn from_owned(ptr: NonNull<LeafNode<K, V>>) -> Self {
BoxedNode { ptr }
}
fn as_ptr(&self) -> NonNull<LeafNode<K, V>> {
NonNull::from(self.ptr)
self.ptr
}
}
/// An owned tree.
///
/// Note that this does not have a destructor, and must be cleaned up manually.
pub struct Root<K, V> {
node: BoxedNode<K, V>,
/// The number of levels below the root node.
height: usize,
}
unsafe impl<K: Sync, V: Sync> Sync for Root<K, V> {}
unsafe impl<K: Send, V: Send> Send for Root<K, V> {}
pub type Root<K, V> = NodeRef<marker::Owned, K, V, marker::LeafOrInternal>;
impl<K, V> Root<K, V> {
/// Returns the number of levels below the root.
pub fn height(&self) -> usize {
self.height
}
/// Returns a new owned tree, with its own root node that is initially empty.
pub fn new_leaf() -> Self {
Root { node: BoxedNode::from_leaf(Box::new(unsafe { LeafNode::new() })), height: 0 }
NodeRef::new().forget_type()
}
}
impl<K, V> NodeRef<marker::Owned, K, V, marker::Leaf> {
fn new() -> Self {
Self::from_new_leaf(Box::new(unsafe { LeafNode::new() }))
}
/// Borrows and returns an immutable reference to the node owned by the root.
pub fn node_as_ref(&self) -> NodeRef<marker::Immut<'_>, K, V, marker::LeafOrInternal> {
NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
fn from_new_leaf(leaf: Box<LeafNode<K, V>>) -> Self {
NodeRef { height: 0, node: NonNull::from(Box::leak(leaf)), _marker: PhantomData }
}
}
impl<K, V> NodeRef<marker::Owned, K, V, marker::Internal> {
fn from_new_internal(internal: Box<InternalNode<K, V>>, height: usize) -> Self {
NodeRef { height, node: NonNull::from(Box::leak(internal)).cast(), _marker: PhantomData }
}
}
impl<K, V, Type> NodeRef<marker::Owned, K, V, Type> {
/// Mutably borrows the owned node. Unlike `reborrow_mut`, this is safe,
/// because the return value cannot be used to destroy the node itself,
/// and there cannot be other references to the tree (except during the
/// process of `into_iter` or `drop`, but that is a horrific already).
pub fn borrow_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, Type> {
NodeRef { height: self.height, node: self.node, _marker: PhantomData }
}
/// Borrows and returns a mutable reference to the node owned by the root.
pub fn node_as_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::LeafOrInternal> {
NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
}
/// Borrows and returns a mutable reference to the leaf node owned by the root.
/// # Safety
/// The root node is a leaf.
unsafe fn leaf_node_as_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::Leaf> {
debug_assert!(self.height == 0);
NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
}
/// Borrows and returns a mutable reference to the internal node owned by the root.
/// # Safety
/// The root node is not a leaf.
unsafe fn internal_node_as_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::Internal> {
debug_assert!(self.height > 0);
NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
}
pub fn node_as_valmut(&mut self) -> NodeRef<marker::ValMut<'_>, K, V, marker::LeafOrInternal> {
NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
}
pub fn into_ref(self) -> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> {
NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
/// Slightly mutably borrows the owned node.
pub fn borrow_valmut(&mut self) -> NodeRef<marker::ValMut<'_>, K, V, Type> {
NodeRef { height: self.height, node: self.node, _marker: PhantomData }
}
/// Packs the reference, aware of type and height, into a type-agnostic pointer.
fn into_boxed_node(self) -> BoxedNode<K, V> {
self.node
BoxedNode::from_owned(self.node)
}
}
impl<K, V> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> {
/// Adds a new internal node with a single edge pointing to the previous root node,
/// make that new node the root node, and return it. This increases the height by 1
/// and is the opposite of `pop_internal_level`.
pub fn push_internal_level(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::Internal> {
let mut new_node = Box::new(unsafe { InternalNode::new() });
new_node.edges[0].write(unsafe { ptr::read(&mut self.node) });
new_node.edges[0].write(BoxedNode::from_owned(self.node));
let mut new_root = NodeRef::from_new_internal(new_node, self.height + 1);
new_root.borrow_mut().first_edge().correct_parent_link();
*self = new_root.forget_type();
self.node = BoxedNode::from_internal(new_node);
self.height += 1;
unsafe {
let mut ret = self.internal_node_as_mut();
ret.reborrow_mut().first_edge().correct_parent_link();
ret
}
// `self.borrow_mut()`, except that we just forgot we're internal now:
NodeRef { height: self.height, node: self.node, _marker: PhantomData }
}
/// Removes the internal root node, using its first child as the new root node.
@ -216,19 +196,17 @@ impl<K, V> Root<K, V> {
/// This decreases the height by 1 and is the opposite of `push_internal_level`.
///
/// Requires exclusive access to the `Root` object but not to the root node;
/// it will not invalidate existing handles or references to the root node.
/// it will not invalidate other handles or references to the root node.
///
/// Panics if there is no internal level, i.e., if the root node is a leaf.
pub fn pop_internal_level(&mut self) {
assert!(self.height > 0);
let top = BoxedNode::as_ptr(&self.node);
let top = self.node;
let mut internal_node = unsafe { self.internal_node_as_mut() };
let internal_node = NodeRef::as_internal_mut(&mut internal_node);
self.node = unsafe { internal_node.edges[0].assume_init_read() };
self.height -= 1;
self.node_as_mut().clear_parent_link();
let internal_node = NodeRef { height: self.height, node: top, _marker: PhantomData };
*self = internal_node.first_edge().descend();
self.borrow_mut().clear_parent_link();
unsafe {
Global.dealloc(top.cast(), Layout::new::<InternalNode<K, V>>());
@ -755,10 +733,10 @@ impl<'a, K: 'a, V: 'a> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
ForceResult::Leaf(_) => None,
ForceResult::Internal(internal) => {
let boxed_node = ptr::read(internal.reborrow().edge_at(idx + 1));
let mut edge = Root { node: boxed_node, height: internal.height - 1 };
let mut edge = Root::from_boxed_node(boxed_node, internal.height - 1);
// In practice, clearing the parent is a waste of time, because we will
// insert the node elsewhere and set its parent link again.
edge.node_as_mut().clear_parent_link();
edge.borrow_mut().clear_parent_link();
Some(edge)
}
};
@ -784,10 +762,10 @@ impl<'a, K: 'a, V: 'a> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
ForceResult::Internal(mut internal) => {
let boxed_node =
slice_remove(internal.reborrow_mut().into_edge_area_slice(), 0);
let mut edge = Root { node: boxed_node, height: internal.height - 1 };
let mut edge = Root::from_boxed_node(boxed_node, internal.height - 1);
// In practice, clearing the parent is a waste of time, because we will
// insert the node elsewhere and set its parent link again.
edge.node_as_mut().clear_parent_link();
edge.borrow_mut().clear_parent_link();
internal.correct_childrens_parent_links(0..old_len);
@ -1028,17 +1006,17 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, mark
} else {
let (middle_kv_idx, insertion) = splitpoint(self.idx);
let middle = unsafe { Handle::new_kv(self.node, middle_kv_idx) };
let (mut left, k, v, mut right) = middle.split();
let mut result = middle.split();
let mut insertion_edge = match insertion {
LeftOrRight::Left(insert_idx) => unsafe {
Handle::new_edge(left.reborrow_mut(), insert_idx)
Handle::new_edge(result.left.reborrow_mut(), insert_idx)
},
LeftOrRight::Right(insert_idx) => unsafe {
Handle::new_edge(right.leaf_node_as_mut(), insert_idx)
Handle::new_edge(result.right.borrow_mut(), insert_idx)
},
};
let val_ptr = insertion_edge.insert_fit(key, val);
(InsertResult::Split(SplitResult { left: left.forget_type(), k, v, right }), val_ptr)
(InsertResult::Split(result), val_ptr)
}
}
}
@ -1092,17 +1070,17 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
} else {
let (middle_kv_idx, insertion) = splitpoint(self.idx);
let middle = unsafe { Handle::new_kv(self.node, middle_kv_idx) };
let (mut left, k, v, mut right) = middle.split();
let mut result = middle.split();
let mut insertion_edge = match insertion {
LeftOrRight::Left(insert_idx) => unsafe {
Handle::new_edge(left.reborrow_mut(), insert_idx)
Handle::new_edge(result.left.reborrow_mut(), insert_idx)
},
LeftOrRight::Right(insert_idx) => unsafe {
Handle::new_edge(right.internal_node_as_mut(), insert_idx)
Handle::new_edge(result.right.borrow_mut(), insert_idx)
},
};
insertion_edge.insert_fit(key, val, edge);
InsertResult::Split(SplitResult { left: left.forget_type(), k, v, right })
InsertResult::Split(result)
}
}
}
@ -1124,16 +1102,16 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, mark
(InsertResult::Fit(handle), ptr) => {
return (InsertResult::Fit(handle.forget_node_type()), ptr);
}
(InsertResult::Split(split), val_ptr) => (split, val_ptr),
(InsertResult::Split(split), val_ptr) => (split.forget_node_type(), val_ptr),
};
loop {
split = match split.left.ascend() {
Ok(parent) => match parent.insert(split.k, split.v, split.right) {
Ok(parent) => match parent.insert(split.kv.0, split.kv.1, split.right) {
InsertResult::Fit(handle) => {
return (InsertResult::Fit(handle.forget_node_type()), val_ptr);
}
InsertResult::Split(split) => split,
InsertResult::Split(split) => split.forget_node_type(),
},
Err(root) => {
return (InsertResult::Split(SplitResult { left: root, ..split }), val_ptr);
@ -1239,14 +1217,14 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, mark
/// - The key and value pointed to by this handle are extracted.
/// - All the key/value pairs to the right of this handle are put into a newly
/// allocated node.
pub fn split(mut self) -> (NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, K, V, Root<K, V>) {
pub fn split(mut self) -> SplitResult<'a, K, V, marker::Leaf> {
unsafe {
let mut new_node = Box::new(LeafNode::new());
let (k, v) = self.split_leaf_data(&mut new_node);
let kv = self.split_leaf_data(&mut new_node);
let right = Root { node: BoxedNode::from_leaf(new_node), height: 0 };
(self.node, k, v, right)
let right = NodeRef::from_new_leaf(new_node);
SplitResult { left: self.node, kv, right }
}
}
@ -1272,7 +1250,7 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
/// - The key and value pointed to by this handle are extracted.
/// - All the edges and key/value pairs to the right of this handle are put into
/// a newly allocated node.
pub fn split(mut self) -> (NodeRef<marker::Mut<'a>, K, V, marker::Internal>, K, V, Root<K, V>) {
pub fn split(mut self) -> SplitResult<'a, K, V, marker::Internal> {
unsafe {
let mut new_node = Box::new(InternalNode::new());
let new_len = self.split_new_node_len();
@ -1282,14 +1260,14 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
new_node.edges.as_mut_ptr(),
new_len + 1,
);
let (k, v) = self.split_leaf_data(&mut new_node.data);
let kv = self.split_leaf_data(&mut new_node.data);
let height = self.node.height;
let mut right = Root { node: BoxedNode::from_internal(new_node), height };
let mut right = NodeRef::from_new_internal(new_node, height);
right.internal_node_as_mut().correct_childrens_parent_links(0..=new_len);
right.borrow_mut().correct_childrens_parent_links(0..=new_len);
(self.node, k, v, right)
SplitResult { left: self.node, kv, right }
}
}
}
@ -1756,20 +1734,30 @@ pub enum ForceResult<Leaf, Internal> {
}
/// Result of insertion, when a node needed to expand beyond its capacity.
/// Does not distinguish between `Leaf` and `Internal` because `Root` doesn't.
pub struct SplitResult<'a, K, V> {
// Altered node in existing tree with elements and edges that belong to the left of `k`.
pub left: NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>,
pub struct SplitResult<'a, K, V, NodeType> {
// Altered node in existing tree with elements and edges that belong to the left of `kv`.
pub left: NodeRef<marker::Mut<'a>, K, V, NodeType>,
// Some key and value split off, to be inserted elsewhere.
pub k: K,
pub v: V,
// Owned, unattached, new node with elements and edges that belong to the right of `k`.
pub right: Root<K, V>,
pub kv: (K, V),
// Owned, unattached, new node with elements and edges that belong to the right of `kv`.
pub right: NodeRef<marker::Owned, K, V, NodeType>,
}
pub enum InsertResult<'a, K, V, Type> {
Fit(Handle<NodeRef<marker::Mut<'a>, K, V, Type>, marker::KV>),
Split(SplitResult<'a, K, V>),
impl<'a, K, V> SplitResult<'a, K, V, marker::Leaf> {
pub fn forget_node_type(self) -> SplitResult<'a, K, V, marker::LeafOrInternal> {
SplitResult { left: self.left.forget_type(), kv: self.kv, right: self.right.forget_type() }
}
}
impl<'a, K, V> SplitResult<'a, K, V, marker::Internal> {
pub fn forget_node_type(self) -> SplitResult<'a, K, V, marker::LeafOrInternal> {
SplitResult { left: self.left.forget_type(), kv: self.kv, right: self.right.forget_type() }
}
}
pub enum InsertResult<'a, K, V, NodeType> {
Fit(Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, marker::KV>),
Split(SplitResult<'a, K, V, NodeType>),
}
pub mod marker {

21
library/alloc/src/collections/btree/node/tests.rs
View File

@ -74,16 +74,19 @@ fn test_splitpoint() {
#[test]
fn test_partial_cmp_eq() {
let mut root1: Root<i32, ()> = Root::new_leaf();
let mut leaf1 = unsafe { root1.leaf_node_as_mut() };
let mut root1 = NodeRef::new();
let mut leaf1 = root1.borrow_mut();
leaf1.push(1, ());
let mut root1 = root1.forget_type();
root1.push_internal_level();
let root2: Root<i32, ()> = Root::new_leaf();
let root2 = Root::new_leaf();
root1.reborrow().assert_back_pointers();
root2.reborrow().assert_back_pointers();
let leaf_edge_1a = root1.node_as_ref().first_leaf_edge().forget_node_type();
let leaf_edge_1b = root1.node_as_ref().last_leaf_edge().forget_node_type();
let top_edge_1 = root1.node_as_ref().first_edge();
let top_edge_2 = root2.node_as_ref().first_edge();
let leaf_edge_1a = root1.reborrow().first_leaf_edge().forget_node_type();
let leaf_edge_1b = root1.reborrow().last_leaf_edge().forget_node_type();
let top_edge_1 = root1.reborrow().first_edge();
let top_edge_2 = root2.reborrow().first_edge();
assert!(leaf_edge_1a == leaf_edge_1a);
assert!(leaf_edge_1a != leaf_edge_1b);
@ -100,8 +103,8 @@ fn test_partial_cmp_eq() {
assert_eq!(top_edge_1.partial_cmp(&top_edge_2), None);
root1.pop_internal_level();
unsafe { root1.into_ref().deallocate_and_ascend() };
unsafe { root2.into_ref().deallocate_and_ascend() };
unsafe { root1.deallocate_and_ascend() };
unsafe { root2.deallocate_and_ascend() };
}
#[test]

12
library/alloc/src/collections/btree/split.rs
View File

@ -9,7 +9,7 @@ impl<K, V> Root<K, V> {
K: Borrow<Q>,
{
debug_assert!(right_root.height() == 0);
debug_assert!(right_root.node_as_ref().len() == 0);
debug_assert!(right_root.len() == 0);
let left_root = self;
for _ in 0..left_root.height() {
@ -17,8 +17,8 @@ impl<K, V> Root<K, V> {
}
{
let mut left_node = left_root.node_as_mut();
let mut right_node = right_root.node_as_mut();
let mut left_node = left_root.borrow_mut();
let mut right_node = right_root.borrow_mut();
loop {
let mut split_edge = match search_node(left_node, key) {
@ -48,7 +48,7 @@ impl<K, V> Root<K, V> {
/// Removes empty levels on the top, but keeps an empty leaf if the entire tree is empty.
fn fix_top(&mut self) {
while self.height() > 0 && self.node_as_ref().len() == 0 {
while self.height() > 0 && self.len() == 0 {
self.pop_internal_level();
}
}
@ -57,7 +57,7 @@ impl<K, V> Root<K, V> {
self.fix_top();
{
let mut cur_node = self.node_as_mut();
let mut cur_node = self.borrow_mut();
while let Internal(node) = cur_node.force() {
let mut last_kv = node.last_kv().consider_for_balancing();
@ -83,7 +83,7 @@ impl<K, V> Root<K, V> {
self.fix_top();
{
let mut cur_node = self.node_as_mut();
let mut cur_node = self.borrow_mut();
while let Internal(node) = cur_node.force() {
let mut first_kv = node.first_kv().consider_for_balancing();

61
src/etc/gdb_providers.py
View File

@ -207,42 +207,43 @@ class StdRefCellProvider:
yield "borrow", self.borrow
# Yields children (in a provider's sense of the word) for a tree headed by a BoxedNode.
# In particular, yields each key/value pair in the node and in any child nodes.
def children_of_node(boxed_node, height):
def cast_to_internal(node):
internal_type_name = node.type.target().name.replace("LeafNode", "InternalNode", 1)
internal_type = lookup_type(internal_type_name)
return node.cast(internal_type.pointer())
# Yields children (in a provider's sense of the word) for a BTreeMap.
def children_of_btree_map(map):
# Yields each key/value pair in the node and in any child nodes.
def children_of_node(node_ptr, height):
def cast_to_internal(node):
internal_type_name = node.type.target().name.replace("LeafNode", "InternalNode", 1)
internal_type = lookup_type(internal_type_name)
return node.cast(internal_type.pointer())
node_ptr = unwrap_unique_or_non_null(boxed_node["ptr"])
leaf = node_ptr.dereference()
keys = leaf["keys"]
vals = leaf["vals"]
edges = cast_to_internal(node_ptr)["edges"] if height > 0 else None
length = int(leaf["len"])
leaf = node_ptr.dereference()
keys = leaf["keys"]
vals = leaf["vals"]
edges = cast_to_internal(node_ptr)["edges"] if height > 0 else None
length = leaf["len"]
for i in xrange(0, length + 1):
if height > 0:
boxed_child_node = edges[i]["value"]["value"]
for child in children_of_node(boxed_child_node, height - 1):
yield child
if i < length:
# Avoid "Cannot perform pointer math on incomplete type" on zero-sized arrays.
key = keys[i]["value"]["value"] if keys.type.sizeof > 0 else "()"
val = vals[i]["value"]["value"] if vals.type.sizeof > 0 else "()"
yield key, val
for i in xrange(0, length + 1):
if height > 0:
boxed_child_node = edges[i]["value"]["value"]
child_node = unwrap_unique_or_non_null(boxed_child_node["ptr"])
for child in children_of_node(child_node, height - 1):
yield child
if i < length:
# Avoid "Cannot perform pointer math on incomplete type" on zero-sized arrays.
key = keys[i]["value"]["value"] if keys.type.sizeof > 0 else "()"
val = vals[i]["value"]["value"] if vals.type.sizeof > 0 else "()"
yield key, val
# Yields children for a BTreeMap.
def children_of_map(map):
if map["length"] > 0:
root = map["root"]
if root.type.name.startswith("core::option::Option<"):
root = root.cast(gdb.lookup_type(root.type.name[21:-1]))
boxed_root_node = root["node"]
node_ptr = root["node"]
if node_ptr.type.name.startswith("alloc::collections::btree::node::BoxedNode<"):
node_ptr = node_ptr["ptr"]
node_ptr = unwrap_unique_or_non_null(node_ptr)
height = root["height"]
for child in children_of_node(boxed_root_node, height):
for child in children_of_node(node_ptr, height):
yield child
@ -255,7 +256,7 @@ class StdBTreeSetProvider:
def children(self):
inner_map = self.valobj["map"]
for i, (child, _) in enumerate(children_of_map(inner_map)):
for i, (child, _) in enumerate(children_of_btree_map(inner_map)):
yield "[{}]".format(i), child
@staticmethod
@ -271,7 +272,7 @@ class StdBTreeMapProvider:
return "BTreeMap(size={})".format(self.valobj["length"])
def children(self):
for i, (key, val) in enumerate(children_of_map(self.valobj)):
for i, (key, val) in enumerate(children_of_btree_map(self.valobj)):
yield "key{}".format(i), key
yield "val{}".format(i), val

4
src/test/debuginfo/pretty-std-collections.rs
View File

@ -102,7 +102,7 @@ fn main() {
btree_set.insert(i);
}
let mut empty_btree_set: BTreeSet<i32> = BTreeSet::new();
let empty_btree_set: BTreeSet<i32> = BTreeSet::new();
// BTreeMap
let mut btree_map = BTreeMap::new();
@ -110,7 +110,7 @@ fn main() {
btree_map.insert(i, i);
}
let mut empty_btree_map: BTreeMap<i32, u32> = BTreeMap::new();
let empty_btree_map: BTreeMap<i32, u32> = BTreeMap::new();
let mut option_btree_map: BTreeMap<bool, Option<bool>> = BTreeMap::new();
option_btree_map.insert(false, None);