rust/compiler/rustc_query_system/src/cache.rs
2020-08-30 18:45:07 +03:00

63 lines
1.7 KiB
Rust

//! Cache for candidate selection.
use crate::dep_graph::DepNodeIndex;
use crate::query::QueryContext;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::sync::HashMapExt;
use rustc_data_structures::sync::Lock;
use std::hash::Hash;
#[derive(Clone)]
pub struct Cache<Key, Value> {
hashmap: Lock<FxHashMap<Key, WithDepNode<Value>>>,
}
impl<Key, Value> Default for Cache<Key, Value> {
fn default() -> Self {
Self { hashmap: Default::default() }
}
}
impl<Key, Value> Cache<Key, Value> {
/// Actually frees the underlying memory in contrast to what stdlib containers do on `clear`
pub fn clear(&self) {
*self.hashmap.borrow_mut() = Default::default();
}
}
impl<Key: Eq + Hash, Value: Clone> Cache<Key, Value> {
pub fn get<CTX: QueryContext>(&self, key: &Key, tcx: CTX) -> Option<Value> {
Some(self.hashmap.borrow().get(key)?.get(tcx))
}
pub fn insert(&self, key: Key, dep_node: DepNodeIndex, value: Value) {
self.hashmap.borrow_mut().insert(key, WithDepNode::new(dep_node, value));
}
pub fn insert_same(&self, key: Key, dep_node: DepNodeIndex, value: Value)
where
Value: Eq,
{
self.hashmap.borrow_mut().insert_same(key, WithDepNode::new(dep_node, value));
}
}
#[derive(Clone, Eq, PartialEq)]
pub struct WithDepNode<T> {
dep_node: DepNodeIndex,
cached_value: T,
}
impl<T: Clone> WithDepNode<T> {
pub fn new(dep_node: DepNodeIndex, cached_value: T) -> Self {
WithDepNode { dep_node, cached_value }
}
pub fn get<CTX: QueryContext>(&self, tcx: CTX) -> T {
tcx.dep_graph().read_index(self.dep_node);
self.cached_value.clone()
}
}