use std::sync::{Arc, Weak};
use crate::state::StateObject;
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub(crate) struct SnapshotWeakSetDebugStats {
pub len: usize,
pub capacity: usize,
}
pub(crate) struct SnapshotWeakSet {
entries: Vec<(usize, Weak<dyn StateObject>)>,
}
impl std::fmt::Debug for SnapshotWeakSet {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("SnapshotWeakSet")
.field("entry_count", &self.entries.len())
.finish()
}
}
impl SnapshotWeakSet {
pub(crate) fn new() -> Self {
Self {
entries: Vec::with_capacity(16),
}
}
#[cfg(test)]
pub(crate) fn add<T: StateObject + 'static>(&mut self, state: &Arc<T>) {
let hash = Arc::as_ptr(state) as *const () as usize;
let trait_obj: Arc<dyn StateObject> = state.clone();
let weak = Arc::downgrade(&trait_obj);
let pos = self.entries.partition_point(|(h, _)| *h < hash);
let has_live = self.entries[pos..]
.iter()
.take_while(|(h, _)| *h == hash)
.any(|(_, existing)| existing.upgrade().is_some());
if has_live {
return;
}
self.entries.insert(pos, (hash, weak));
if self.entries.len() == self.entries.capacity() {
self.entries.reserve(self.entries.len());
}
}
pub(crate) fn add_trait_object(&mut self, state: &Arc<dyn StateObject>) {
let hash = Arc::as_ptr(state) as *const () as usize;
let weak = Arc::downgrade(state);
let pos = self.entries.partition_point(|(h, _)| *h < hash);
let has_live = self.entries[pos..]
.iter()
.take_while(|(h, _)| *h == hash)
.any(|(_, existing)| existing.upgrade().is_some());
if has_live {
return;
}
self.entries.insert(pos, (hash, weak));
if self.entries.len() == self.entries.capacity() {
self.entries.reserve(self.entries.len());
}
}
pub(crate) fn remove_if<F>(&mut self, mut predicate: F)
where
F: FnMut(&dyn StateObject) -> bool,
{
self.entries.retain(|(_, weak)| {
if let Some(strong) = weak.upgrade() {
predicate(&*strong)
} else {
false
}
});
}
pub(crate) fn len(&self) -> usize {
self.entries.len()
}
pub(crate) fn is_empty(&self) -> bool {
self.entries.is_empty()
}
pub(crate) fn debug_stats(&self) -> SnapshotWeakSetDebugStats {
SnapshotWeakSetDebugStats {
len: self.entries.len(),
capacity: self.entries.capacity(),
}
}
#[cfg(test)]
pub(crate) fn alive_count(&self) -> usize {
self.entries
.iter()
.filter(|(_, weak)| weak.upgrade().is_some())
.count()
}
}
impl Default for SnapshotWeakSet {
fn default() -> Self {
Self::new()
}
}
#[cfg(test)]
#[expect(clippy::arc_with_non_send_sync)]
#[path = "tests/snapshot_weak_set_tests.rs"]
mod tests;