Switch the bloom element list to a SmallVec and track pushed hashes.

This commit is contained in:
Bobby Holley 2017-05-24 16:30:18 +02:00
parent 0f0e0d81fb
commit 5d5c715152

View file

@ -46,8 +46,29 @@ pub struct StyleBloom<E: TElement> {
/// The bloom filter per se.
filter: Box<BloomFilter>,
/// The stack of elements that this bloom filter contains.
elements: Vec<SendElement<E>>,
/// The stack of elements that this bloom filter contains, along with the
/// number of hashes pushed for each element.
elements: SmallVec<[PushedElement<E>; 16]>,
/// Stack of hashes that have been pushed onto this filter.
pushed_hashes: SmallVec<[u32; 64]>,
}
struct PushedElement<E: TElement> {
/// The element that was pushed.
element: SendElement<E>,
/// The number of hashes pushed for the element.
num_hashes: usize,
}
impl<E: TElement> PushedElement<E> {
fn new(el: E, num_hashes: usize) -> Self {
PushedElement {
element: unsafe { SendElement::new(el) },
num_hashes: num_hashes,
}
}
}
fn each_relevant_element_hash<E, F>(element: E, mut f: F)
@ -75,7 +96,8 @@ impl<E: TElement> StyleBloom<E> {
pub fn new() -> Self {
StyleBloom {
filter: Box::new(BloomFilter::new()),
elements: vec![],
elements: Default::default(),
pushed_hashes: Default::default(),
}
}
@ -98,23 +120,36 @@ impl<E: TElement> StyleBloom<E> {
/// Same as `push`, but without asserting, in order to use it from
/// `rebuild`.
fn push_internal(&mut self, element: E) {
let mut count = 0;
each_relevant_element_hash(element, |hash| {
count += 1;
self.filter.insert_hash(hash);
self.pushed_hashes.push(hash);
});
self.elements.push(unsafe { SendElement::new(element) });
self.elements.push(PushedElement::new(element, count));
}
/// Pop the last element in the bloom filter and return it.
#[inline]
fn pop(&mut self) -> Option<E> {
let popped = self.elements.pop().map(|el| *el);
let (popped_element, num_hashes) = match self.elements.pop() {
None => return None,
Some(x) => (*x.element, x.num_hashes),
};
if let Some(popped) = popped {
each_relevant_element_hash(popped, |hash| {
self.filter.remove_hash(hash);
})
// Verify that the pushed hashes match the ones we'd get from the element.
let mut expected_hashes = vec![];
if cfg!(debug_assertions) {
each_relevant_element_hash(popped_element, |hash| expected_hashes.push(hash));
}
popped
for _ in 0..num_hashes {
let hash = self.pushed_hashes.pop().unwrap();
debug_assert_eq!(expected_hashes.pop().unwrap(), hash);
self.filter.remove_hash(hash);
}
Some(popped_element)
}
/// Returns true if the bloom filter is empty.
@ -158,7 +193,7 @@ impl<E: TElement> StyleBloom<E> {
if cfg!(debug_assertions) {
let mut checked = 0;
while let Some(parent) = element.traversal_parent() {
assert_eq!(parent, *self.elements[self.elements.len() - 1 - checked]);
assert_eq!(parent, *(self.elements[self.elements.len() - 1 - checked].element));
element = parent;
checked += 1;
}
@ -171,7 +206,7 @@ impl<E: TElement> StyleBloom<E> {
/// (if any) and its ancestors.
#[inline]
pub fn current_parent(&self) -> Option<E> {
self.elements.last().map(|el| **el)
self.elements.last().map(|ref el| *el.element)
}
/// Insert the parents of an element in the bloom filter, trying to recover
@ -268,7 +303,7 @@ impl<E: TElement> StyleBloom<E> {
//
// Thus it's possible with Gecko that we do not find any common
// ancestor.
while **self.elements.last().unwrap() != common_parent {
while *(self.elements.last().unwrap().element) != common_parent {
parents_to_insert.push(common_parent);
self.pop().unwrap();
common_parent = match common_parent.traversal_parent() {