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BTreeMap: tag internal functions with preconditions as unsafe #68418

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BTreeMap: tag internal functions with preconditions as unsafe #68418

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182af10
Declare unsafe all functions that can't handle shared roots
ssomers Jan 21, 2020
cc9ae53
Declare unsafe all functions that debug_assert something other than s…
ssomers Jan 21, 2020
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82 changes: 42 additions & 40 deletions src/liballoc/collections/btree/map.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -156,10 +156,10 @@ impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> {

let mut in_edge = leaf.first_edge();
while let Ok(kv) = in_edge.right_kv() {
let (k, v) = kv.into_kv();
let (k, v) = unsafe { kv.into_kv() };
in_edge = kv.right_edge();

out_node.push(k.clone(), v.clone());
unsafe { out_node.push(k.clone(), v.clone()) };
out_tree.length += 1;
}
}
Expand All @@ -170,10 +170,10 @@ impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> {
let mut out_tree = clone_subtree(internal.first_edge().descend());

{
let mut out_node = out_tree.root.push_level();
let mut out_node = unsafe { out_tree.root.push_level() };
let mut in_edge = internal.first_edge();
while let Ok(kv) = in_edge.right_kv() {
let (k, v) = kv.into_kv();
let (k, v) = unsafe { kv.into_kv() };
in_edge = kv.right_edge();

let k = (*k).clone();
Expand All @@ -189,7 +189,7 @@ impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> {
(root, length)
};

out_node.push(k, v, subroot);
unsafe { out_node.push(k, v, subroot) };
out_tree.length += 1 + sublength;
}
}
Expand Down Expand Up @@ -218,7 +218,7 @@ where

fn get(&self, key: &Q) -> Option<&K> {
match search::search_tree(self.root.as_ref(), key) {
Found(handle) => Some(handle.into_kv().0),
Found(handle) => Some(unsafe { handle.into_kv().0 }),
GoDown(_) => None,
}
}
Expand All @@ -237,7 +237,7 @@ where
fn replace(&mut self, key: K) -> Option<K> {
self.ensure_root_is_owned();
match search::search_tree::<marker::Mut<'_>, K, (), K>(self.root.as_mut(), &key) {
Found(handle) => Some(mem::replace(handle.into_kv_mut().0, key)),
Found(handle) => Some(mem::replace(unsafe { handle.into_kv_mut().0 }, key)),
GoDown(handle) => {
VacantEntry { key, handle, length: &mut self.length, _marker: PhantomData }
.insert(());
Expand Down Expand Up @@ -536,7 +536,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
Q: Ord,
{
match search::search_tree(self.root.as_ref(), key) {
Found(handle) => Some(handle.into_kv().1),
Found(handle) => Some(unsafe { handle.into_kv().1 }),
GoDown(_) => None,
}
}
Expand All @@ -563,7 +563,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
Q: Ord,
{
match search::search_tree(self.root.as_ref(), k) {
Found(handle) => Some(handle.into_kv()),
Found(handle) => Some(unsafe { handle.into_kv() }),
GoDown(_) => None,
}
}
Expand Down Expand Up @@ -592,7 +592,8 @@ impl<K: Ord, V> BTreeMap<K, V> {
K: Borrow<T>,
{
let front = first_leaf_edge(self.root.as_ref());
front.right_kv().ok().map(Handle::into_kv)
let handle = front.right_kv().ok()?;
Some(unsafe { handle.into_kv() })
}

/// Returns the first entry in the map for in-place manipulation.
Expand Down Expand Up @@ -623,7 +624,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
match self.length {
0 => None,
_ => Some(OccupiedEntry {
handle: self.root.as_mut().first_kv(),
handle: unsafe { self.root.as_mut().first_kv() },
length: &mut self.length,
_marker: PhantomData,
}),
Expand Down Expand Up @@ -653,7 +654,8 @@ impl<K: Ord, V> BTreeMap<K, V> {
K: Borrow<T>,
{
let back = last_leaf_edge(self.root.as_ref());
back.left_kv().ok().map(Handle::into_kv)
let handle = back.left_kv().ok()?;
unsafe { Some(handle.into_kv()) }
}

/// Returns the last entry in the map for in-place manipulation.
Expand Down Expand Up @@ -684,7 +686,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
match self.length {
0 => None,
_ => Some(OccupiedEntry {
handle: self.root.as_mut().last_kv(),
handle: unsafe { self.root.as_mut().last_kv() },
length: &mut self.length,
_marker: PhantomData,
}),
Expand Down Expand Up @@ -744,7 +746,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
Q: Ord,
{
match search::search_tree(self.root.as_mut(), key) {
Found(handle) => Some(handle.into_kv_mut().1),
Found(handle) => Some(unsafe { handle.into_kv_mut().1 }),
GoDown(_) => None,
}
}
Expand Down Expand Up @@ -995,7 +997,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
for (key, value) in iter {
// Try to push key-value pair into the current leaf node.
if cur_node.len() < node::CAPACITY {
cur_node.push(key, value);
unsafe { cur_node.push(key, value) };
} else {
// No space left, go up and push there.
let mut open_node;
Expand All @@ -1015,7 +1017,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
}
Err(node) => {
// We are at the top, create a new root node and push there.
open_node = node.into_root_mut().push_level();
open_node = unsafe { node.into_root_mut().push_level() };
break;
}
}
Expand All @@ -1025,9 +1027,9 @@ impl<K: Ord, V> BTreeMap<K, V> {
let tree_height = open_node.height() - 1;
let mut right_tree = node::Root::new_leaf();
for _ in 0..tree_height {
right_tree.push_level();
unsafe { right_tree.push_level() };
}
open_node.push(key, value, right_tree);
unsafe { open_node.push(key, value, right_tree) };

// Go down to the right-most leaf again.
cur_node = last_leaf_edge(open_node.forget_type()).into_node();
Expand All @@ -1050,7 +1052,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
Ok(left) => left,
Err(_) => unreachable!(),
};
last_kv.bulk_steal_left(node::MIN_LEN - right_child_len);
unsafe { last_kv.bulk_steal_left(node::MIN_LEN - right_child_len) };
last_edge = last_kv.right_edge();
}

Expand Down Expand Up @@ -1102,7 +1104,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
let mut right = Self::new();
right.root = node::Root::new_leaf();
for _ in 0..(self.root.as_ref().height()) {
right.root.push_level();
unsafe { right.root.push_level() };
}

{
Expand All @@ -1116,7 +1118,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
GoDown(handle) => handle,
};

split_edge.move_suffix(&mut right_node);
unsafe { split_edge.move_suffix(&mut right_node) };

match (split_edge.force(), right_node.force()) {
(Internal(edge), Internal(node)) => {
Expand Down Expand Up @@ -1186,7 +1188,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
break;
}
}
self.root.pop_level();
unsafe { self.root.pop_level() };
}
}

Expand All @@ -1197,15 +1199,15 @@ impl<K: Ord, V> BTreeMap<K, V> {
let mut cur_node = self.root.as_mut();

while let Internal(node) = cur_node.force() {
let mut last_kv = node.last_kv();
let mut last_kv = unsafe { node.last_kv() };

if last_kv.can_merge() {
cur_node = last_kv.merge().descend();
cur_node = unsafe { last_kv.merge() }.descend();
} else {
let right_len = last_kv.reborrow().right_edge().descend().len();
// `MINLEN + 1` to avoid readjust if merge happens on the next level.
if right_len < node::MIN_LEN + 1 {
last_kv.bulk_steal_left(node::MIN_LEN + 1 - right_len);
unsafe { last_kv.bulk_steal_left(node::MIN_LEN + 1 - right_len) };
}
cur_node = last_kv.right_edge().descend();
}
Expand All @@ -1223,14 +1225,14 @@ impl<K: Ord, V> BTreeMap<K, V> {
let mut cur_node = self.root.as_mut();

while let Internal(node) = cur_node.force() {
let mut first_kv = node.first_kv();
let mut first_kv = unsafe { node.first_kv() };

if first_kv.can_merge() {
cur_node = first_kv.merge().descend();
cur_node = unsafe { first_kv.merge().descend() };
} else {
let left_len = first_kv.reborrow().left_edge().descend().len();
if left_len < node::MIN_LEN + 1 {
first_kv.bulk_steal_right(node::MIN_LEN + 1 - left_len);
unsafe { first_kv.bulk_steal_right(node::MIN_LEN + 1 - left_len) };
}
cur_node = first_kv.left_edge().descend();
}
Expand Down Expand Up @@ -2387,7 +2389,7 @@ impl<'a, K: Ord, V> VacantEntry<'a, K, V> {
let mut ins_edge;

let mut cur_parent = match self.handle.insert(self.key, value) {
(Fit(handle), _) => return handle.into_kv_mut().1,
(Fit(handle), _) => return unsafe { handle.into_kv_mut().1 },
(Split(left, k, v, right), ptr) => {
ins_k = k;
ins_v = v;
Expand All @@ -2409,7 +2411,7 @@ impl<'a, K: Ord, V> VacantEntry<'a, K, V> {
}
},
Err(root) => {
root.push_level().push(ins_k, ins_v, ins_edge);
unsafe { root.push_level().push(ins_k, ins_v, ins_edge) };
return unsafe { &mut *out_ptr };
}
}
Expand All @@ -2431,7 +2433,7 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
/// ```
#[stable(feature = "map_entry_keys", since = "1.10.0")]
pub fn key(&self) -> &K {
self.handle.reborrow().into_kv().0
unsafe { self.handle.reborrow().into_kv().0 }
}

/// Take ownership of the key and value from the map.
Expand Down Expand Up @@ -2475,7 +2477,7 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn get(&self) -> &V {
self.handle.reborrow().into_kv().1
unsafe { self.handle.reborrow().into_kv().1 }
}

/// Gets a mutable reference to the value in the entry.
Expand Down Expand Up @@ -2506,7 +2508,7 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn get_mut(&mut self) -> &mut V {
self.handle.kv_mut().1
unsafe { self.handle.kv_mut().1 }
}

/// Converts the entry into a mutable reference to its value.
Expand All @@ -2532,7 +2534,7 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn into_mut(self) -> &'a mut V {
self.handle.into_kv_mut().1
unsafe { self.handle.into_kv_mut().1 }
}

/// Sets the value of the entry with the `OccupiedEntry`'s key,
Expand Down Expand Up @@ -2584,17 +2586,17 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {

let (small_leaf, old_key, old_val) = match self.handle.force() {
Leaf(leaf) => {
let (hole, old_key, old_val) = leaf.remove();
let (hole, old_key, old_val) = unsafe { leaf.remove() };
(hole.into_node(), old_key, old_val)
}
Internal(mut internal) => {
let key_loc = internal.kv_mut().0 as *mut K;
let val_loc = internal.kv_mut().1 as *mut V;
let key_loc = unsafe { internal.kv_mut().0 as *mut K };
let val_loc = unsafe { internal.kv_mut().1 as *mut V };

let to_remove = first_leaf_edge(internal.right_edge().descend()).right_kv().ok();
let to_remove = unsafe { unwrap_unchecked(to_remove) };

let (hole, key, val) = to_remove.remove();
let (hole, key, val) = unsafe { to_remove.remove() };

let old_key = unsafe { mem::replace(&mut *key_loc, key) };
let old_val = unsafe { mem::replace(&mut *val_loc, val) };
Expand All @@ -2612,7 +2614,7 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
Merged(parent) => {
if parent.len() == 0 {
// We must be at the root
parent.into_root_mut().pop_level();
unsafe { parent.into_root_mut().pop_level() };
break;
} else {
cur_node = parent.forget_type();
Expand Down Expand Up @@ -2653,7 +2655,7 @@ fn handle_underfull_node<K, V>(
};

if handle.can_merge() {
Merged(handle.merge().into_node())
Merged(unsafe { handle.merge() }.into_node())
} else {
if is_left {
handle.steal_left();
Expand Down
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