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perf: consolidate paths to parent path when threshold exceeded for fsevents watcher #60

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Merged
sapphi-red merged 1 commit into from
Dec 19, 2025
Merged

perf: consolidate paths to parent path when threshold exceeded for fsevents watcher #60

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73 changes: 73 additions & 0 deletions notify/src/consolidating_path_trie.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,10 +23,18 @@ impl<T> PathTrieNode<T> {
.binary_search_by(|(k, _)| k.as_os_str().cmp(key))
}

pub(crate) fn children_len(&self) -> usize {
self.children.len()
}

pub fn remove_children(&mut self) {
self.children.clear();
}

pub fn set_value(&mut self, value: T) {
self.value = Some(value);
}

pub fn descendants(&self) -> impl Iterator<Item = (PathBuf, &T)> {
PathTrieIter::new(self)
}
Expand Down Expand Up @@ -65,6 +73,19 @@ impl<T> PathTrie<T> {
current
}

/// Get the node associated with the given path.
/// It may not have a value.
pub fn get_node_mut(&mut self, path: impl AsRef<Path>) -> Option<&mut PathTrieNode<T>> {
let path = path.as_ref();
let mut current = &mut self.root;
for component in path.components() {
let key = component.as_os_str();
let idx = current.get_child_index(key).ok()?;
current = &mut current.children[idx].1;
}
Some(current)
}

/// Get the node associated with the given path.
/// It only returns if the node has a value.
#[expect(dead_code)]
Expand Down Expand Up @@ -155,6 +176,8 @@ pub struct ConsolidatingPathTrie {
}

impl ConsolidatingPathTrie {
const CHILDREN_CONSOLIDATION_THRESHOLD: usize = 10;

pub fn new() -> Self {
Self {
trie: PathTrie::new(),
Expand All @@ -168,6 +191,17 @@ impl ConsolidatingPathTrie {
}
let inserted = self.trie.insert(path, ());
inserted.remove_children();

for ancestor_path in path.ancestors().skip(1) {
if let Some(parent_node) = self.trie.get_node_mut(ancestor_path)
&& parent_node.children_len() >= Self::CHILDREN_CONSOLIDATION_THRESHOLD
{
parent_node.remove_children();
parent_node.set_value(());
} else {
break;
}
}
}

pub fn values(&self) -> Vec<PathBuf> {
Expand Down Expand Up @@ -236,4 +270,43 @@ mod tests {
ct.insert(PathBuf::from("/a/b"));
assert_eq!(ct.values(), vec![PathBuf::from("/a/b")]);
}

#[test]
fn consolidate_to_single_parent() {
let mut cr = ConsolidatingPathTrie::new();
for i in 1..=ConsolidatingPathTrie::CHILDREN_CONSOLIDATION_THRESHOLD {
cr.insert(PathBuf::from(format!("/a/b/c{i}")));
}
assert_eq!(cr.values(), vec![PathBuf::from("/a/b")]);
}

#[test]
fn consolidate_to_single_parent_nested1() {
let mut cr = ConsolidatingPathTrie::new();
for i in 1..ConsolidatingPathTrie::CHILDREN_CONSOLIDATION_THRESHOLD {
cr.insert(PathBuf::from(format!("/a/b/c{i}")));
}
for i in 1..=ConsolidatingPathTrie::CHILDREN_CONSOLIDATION_THRESHOLD {
cr.insert(PathBuf::from(format!("/a/b/cc/d{i}")));
}
assert_eq!(cr.values(), vec![PathBuf::from("/a/b")]);
}

#[test]
fn consolidate_to_single_parent_nested2() {
let mut cr = ConsolidatingPathTrie::new();
cr.insert(PathBuf::from("/a/b/c1"));
cr.insert(PathBuf::from("/a/b/c2"));
for i in 1..=ConsolidatingPathTrie::CHILDREN_CONSOLIDATION_THRESHOLD {
cr.insert(PathBuf::from(format!("/a/b/c3/d{i}")));
}
assert_eq!(
cr.values(),
vec![
PathBuf::from("/a/b/c1"),
PathBuf::from("/a/b/c2"),
PathBuf::from("/a/b/c3")
]
);
}
}