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avoid as_leaf_mut asserting exclusive access
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@RalfJung
RalfJung committed Dec 9, 2018
1 parent 0e70c26 commit 4558340
Showing 1 changed file with 33 additions and 30 deletions.
63 changes: 33 additions & 30 deletions src/liballoc/collections/btree/node.rs
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Expand Up @@ -307,7 +307,7 @@ impl<K, V> Root<K, V> {
.node)
};
self.height -= 1;
self.as_mut().as_leaf_mut().parent = ptr::null();
unsafe { (*self.as_mut().as_leaf_mut()).parent = ptr::null(); }

unsafe {
Global.dealloc(NonNull::from(top).cast(), Layout::new::<InternalNode<K, V>>());
Expand Down Expand Up @@ -570,9 +570,10 @@ impl<'a, K, V, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
}
}

fn as_leaf_mut(&mut self) -> &mut LeafNode<K, V> {
// We are mutable, so we cannot be the root, so this is okay.
unsafe { self.node.as_mut() }
/// Returns a raw ptr to avoid asserting exclusive access to the entire node.
fn as_leaf_mut(&mut self) -> *mut LeafNode<K, V> {
// We are mutable, so we cannot be the root, so accessing this as a leaf is okay.
self.node.as_ptr()
}

fn keys_mut(&mut self) -> &mut [K] {
Expand Down Expand Up @@ -659,7 +660,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
} else {
unsafe {
slice::from_raw_parts_mut(
self.as_leaf_mut().keys.as_mut_ptr() as *mut K,
(*self.as_leaf_mut()).keys.as_mut_ptr() as *mut K,
self.len()
)
}
Expand All @@ -670,7 +671,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
debug_assert!(!self.is_shared_root());
unsafe {
slice::from_raw_parts_mut(
self.as_leaf_mut().vals.as_mut_ptr() as *mut V,
(*self.as_leaf_mut()).vals.as_mut_ptr() as *mut V,
self.len()
)
}
Expand All @@ -694,9 +695,9 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Leaf> {
unsafe {
ptr::write(self.keys_mut().get_unchecked_mut(idx), key);
ptr::write(self.vals_mut().get_unchecked_mut(idx), val);
}

self.as_leaf_mut().len += 1;
(*self.as_leaf_mut()).len += 1;
}
}

/// Adds a key/value pair to the beginning of the node.
Expand All @@ -708,9 +709,9 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Leaf> {
unsafe {
slice_insert(self.keys_mut(), 0, key);
slice_insert(self.vals_mut(), 0, val);
}

self.as_leaf_mut().len += 1;
(*self.as_leaf_mut()).len += 1;
}
}
}

Expand All @@ -729,7 +730,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
ptr::write(self.vals_mut().get_unchecked_mut(idx), val);
ptr::write(self.as_internal_mut().edges.get_unchecked_mut(idx + 1), edge.node);

self.as_leaf_mut().len += 1;
(*self.as_leaf_mut()).len += 1;

Handle::new_edge(self.reborrow_mut(), idx + 1).correct_parent_link();
}
Expand Down Expand Up @@ -765,7 +766,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
edge.node
);

self.as_leaf_mut().len += 1;
(*self.as_leaf_mut()).len += 1;

self.correct_all_childrens_parent_links();
}
Expand All @@ -789,12 +790,12 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
ForceResult::Internal(internal) => {
let edge = ptr::read(internal.as_internal().edges.get_unchecked(idx + 1));
let mut new_root = Root { node: edge, height: internal.height - 1 };
new_root.as_mut().as_leaf_mut().parent = ptr::null();
(*new_root.as_mut().as_leaf_mut()).parent = ptr::null();
Some(new_root)
}
};

self.as_leaf_mut().len -= 1;
(*self.as_leaf_mut()).len -= 1;
(key, val, edge)
}
}
Expand Down Expand Up @@ -822,7 +823,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
);

let mut new_root = Root { node: edge, height: internal.height - 1 };
new_root.as_mut().as_leaf_mut().parent = ptr::null();
(*new_root.as_mut().as_leaf_mut()).parent = ptr::null();

for i in 0..old_len {
Handle::new_edge(internal.reborrow_mut(), i).correct_parent_link();
Expand All @@ -832,7 +833,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
}
};

self.as_leaf_mut().len -= 1;
(*self.as_leaf_mut()).len -= 1;

(key, val, edge)
}
Expand Down Expand Up @@ -1023,7 +1024,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge
slice_insert(self.node.keys_mut(), self.idx, key);
slice_insert(self.node.vals_mut(), self.idx, val);

self.node.as_leaf_mut().len += 1;
(*self.node.as_leaf_mut()).len += 1;

self.node.vals_mut().get_unchecked_mut(self.idx)
}
Expand Down Expand Up @@ -1066,8 +1067,10 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
let idx = self.idx as u16;
let ptr = self.node.as_internal_mut() as *mut _;
let mut child = self.descend();
child.as_leaf_mut().parent = ptr;
child.as_leaf_mut().parent_idx.set(idx);
unsafe {
(*child.as_leaf_mut()).parent = ptr;
(*child.as_leaf_mut()).parent_idx.set(idx);
}
}

/// Unsafely asserts to the compiler some static information about whether the underlying
Expand Down Expand Up @@ -1215,7 +1218,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::KV>
new_len
);

self.node.as_leaf_mut().len = self.idx as u16;
(*self.node.as_leaf_mut()).len = self.idx as u16;
new_node.len = new_len as u16;

(
Expand All @@ -1237,7 +1240,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::KV>
unsafe {
let k = slice_remove(self.node.keys_mut(), self.idx);
let v = slice_remove(self.node.vals_mut(), self.idx);
self.node.as_leaf_mut().len -= 1;
(*self.node.as_leaf_mut()).len -= 1;
(self.left_edge(), k, v)
}
}
Expand Down Expand Up @@ -1278,7 +1281,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
new_len + 1
);

self.node.as_leaf_mut().len = self.idx as u16;
(*self.node.as_leaf_mut()).len = self.idx as u16;
new_node.data.len = new_len as u16;

let mut new_root = Root {
Expand Down Expand Up @@ -1352,9 +1355,9 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
for i in self.idx+1..self.node.len() {
Handle::new_edge(self.node.reborrow_mut(), i).correct_parent_link();
}
self.node.as_leaf_mut().len -= 1;
(*self.node.as_leaf_mut()).len -= 1;

left_node.as_leaf_mut().len += right_len as u16 + 1;
(*left_node.as_leaf_mut()).len += right_len as u16 + 1;

if self.node.height > 1 {
ptr::copy_nonoverlapping(
Expand Down Expand Up @@ -1464,8 +1467,8 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
move_kv(left_kv, new_left_len, parent_kv, 0, 1);
}

left_node.reborrow_mut().as_leaf_mut().len -= count as u16;
right_node.reborrow_mut().as_leaf_mut().len += count as u16;
(*left_node.reborrow_mut().as_leaf_mut()).len -= count as u16;
(*right_node.reborrow_mut().as_leaf_mut()).len += count as u16;

match (left_node.force(), right_node.force()) {
(ForceResult::Internal(left), ForceResult::Internal(mut right)) => {
Expand Down Expand Up @@ -1525,8 +1528,8 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
new_right_len);
}

left_node.reborrow_mut().as_leaf_mut().len += count as u16;
right_node.reborrow_mut().as_leaf_mut().len -= count as u16;
(*left_node.reborrow_mut().as_leaf_mut()).len += count as u16;
(*right_node.reborrow_mut().as_leaf_mut()).len -= count as u16;

match (left_node.force(), right_node.force()) {
(ForceResult::Internal(left), ForceResult::Internal(mut right)) => {
Expand Down Expand Up @@ -1617,8 +1620,8 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, ma

move_kv(left_kv, left_new_len, right_kv, 0, right_new_len);

left_node.reborrow_mut().as_leaf_mut().len = left_new_len as u16;
right_node.reborrow_mut().as_leaf_mut().len = right_new_len as u16;
(*left_node.reborrow_mut().as_leaf_mut()).len = left_new_len as u16;
(*right_node.reborrow_mut().as_leaf_mut()).len = right_new_len as u16;

match (left_node.force(), right_node.force()) {
(ForceResult::Internal(left), ForceResult::Internal(right)) => {
Expand Down

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