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use std::fmt::Debug;
use std::sync::Arc;
use crossbeam_skiplist::SkipMap;
use parking_lot::Mutex;
use crate::cdc::change::ChangeEventUnassigned;
use crate::core::node::NodeLike;
type OldVersion<Node> = Arc<Mutex<Node>>;
type CurrentVersion<Node> = Arc<Mutex<Node>>;
pub enum Operation<T: Send + Ord, Node: NodeLike<T>> {
Split(OldVersion<Node>, T, T),
UpdateMax(CurrentVersion<Node>, T),
MakeUnreachable(CurrentVersion<Node>, T),
}
impl<T, Node> Operation<T, Node>
where
T: Debug + Ord + Send + Clone + 'static,
Node: NodeLike<T> + Send + 'static,
{
pub fn commit(
self,
index: &SkipMap<T, Arc<Mutex<Node>>>,
) -> Result<(Option<T>, Vec<ChangeEventUnassigned<T>>), ()> {
match self {
Operation::Split(old_node, old_max, value) => {
let mut guard = old_node.lock_arc();
if let Some(entry) = index.get(&old_max) {
if Arc::ptr_eq(entry.value(), &old_node) {
let mut cdc = vec![];
#[cfg(feature = "cdc")]
let max_value = guard
.max()
.expect("node should be non empty if split")
.clone();
entry.remove();
let mut new_vec = guard.halve();
#[cfg(feature = "cdc")]
{
let node_split = ChangeEventUnassigned::SplitNode {
max_value,
split_index: guard.len(),
};
cdc.push(node_split);
}
let mut old_value: Option<T> = None;
let mut insert_attempted = false;
if let Some(max) = guard.max().cloned() {
if max > value {
let (inserted, idx) = NodeLike::insert(&mut *guard, value.clone());
insert_attempted = true;
if !inserted {
old_value = NodeLike::replace(&mut *guard, idx, value.clone());
#[cfg(feature = "cdc")]
{
let value_insertion = ChangeEventUnassigned::RemoveAt {
max_value: max.clone(),
index: idx,
value: old_value.clone().unwrap(),
};
cdc.push(value_insertion);
}
}
#[cfg(feature = "cdc")]
{
let value_insertion = ChangeEventUnassigned::InsertAt {
max_value: max.clone(),
index: idx,
value: value.clone(),
};
cdc.push(value_insertion);
}
}
index.insert(max, old_node.clone());
}
if let Some(mut max) = new_vec.max().cloned() {
if !insert_attempted {
let (inserted, idx) = NodeLike::insert(&mut new_vec, value.clone());
let old_max = max.clone();
if inserted {
if value > max {
max = value.clone()
}
} else {
old_value = NodeLike::replace(&mut new_vec, idx, value.clone());
#[cfg(feature = "cdc")]
{
let value_insertion = ChangeEventUnassigned::RemoveAt {
max_value: old_max.clone(),
index: idx,
value: old_value.clone().unwrap(),
};
cdc.push(value_insertion);
}
}
#[cfg(feature = "cdc")]
{
let value_insertion = ChangeEventUnassigned::InsertAt {
max_value: old_max.clone(),
index: idx,
value: value.clone(),
};
cdc.push(value_insertion);
}
}
let new_node = Arc::new(Mutex::new(new_vec));
index.insert(max, new_node);
}
return Ok((old_value, cdc));
}
}
Err(())
}
Operation::UpdateMax(node, old_max) => {
let guard = node.lock_arc();
if guard.max().is_none() {
return Ok((None, vec![]));
}
let new_max = guard.max().unwrap();
if let Some(entry) = index.get(&old_max) {
if Arc::ptr_eq(entry.value(), &node) {
let cdc = vec![];
return Ok(match new_max.cmp(&old_max) {
std::cmp::Ordering::Equal => (None, cdc),
std::cmp::Ordering::Greater => {
index.remove(&old_max);
index.insert(new_max.clone(), node.clone());
(None, cdc)
}
std::cmp::Ordering::Less => {
index.remove(&old_max);
index.insert(new_max.clone(), node.clone());
(None, cdc)
}
});
}
}
Err(())
}
Operation::MakeUnreachable(node, old_max) => {
let guard = node.lock_arc();
let new_max = guard.max();
if let Some(entry) = index.get(&old_max) {
if Arc::ptr_eq(entry.value(), &node) {
return match new_max.cmp(&Some(&old_max)) {
std::cmp::Ordering::Less => {
let mut cdc = vec![];
#[cfg(feature = "cdc")]
{
let node_removal = ChangeEventUnassigned::RemoveNode {
max_value: old_max.clone(),
};
cdc.push(node_removal);
}
index.remove(&old_max);
Ok((None, cdc))
}
_ => Err(()),
};
}
}
Err(())
}
}
}
}