use std::any::{Any, TypeId};
use std::borrow::Borrow;
use std::cell::RefCell;
use std::cmp::Ordering;
use std::collections::HashMap;
use std::hash::{Hash, Hasher};
use std::marker::PhantomData;
use std::ops::Deref;
use std::path::PathBuf;
use std::sync::{LazyLock, Mutex};
use std::{fmt, mem};
use crate::core::builder::Step;
pub struct Interned<T>(usize, PhantomData<*const T>);
impl<T: Internable + Default> Default for Interned<T> {
fn default() -> Self {
T::default().intern()
}
}
impl<T> Copy for Interned<T> {}
impl<T> Clone for Interned<T> {
fn clone(&self) -> Interned<T> {
*self
}
}
impl<T> PartialEq for Interned<T> {
fn eq(&self, other: &Self) -> bool {
self.0 == other.0
}
}
impl<T> Eq for Interned<T> {}
impl PartialEq<str> for Interned<String> {
fn eq(&self, other: &str) -> bool {
*self == other
}
}
impl PartialEq<&str> for Interned<String> {
fn eq(&self, other: &&str) -> bool {
**self == **other
}
}
impl<T> PartialEq<&Interned<T>> for Interned<T> {
fn eq(&self, other: &&Self) -> bool {
self.0 == other.0
}
}
impl<T> PartialEq<Interned<T>> for &Interned<T> {
fn eq(&self, other: &Interned<T>) -> bool {
self.0 == other.0
}
}
unsafe impl<T> Send for Interned<T> {}
unsafe impl<T> Sync for Interned<T> {}
impl fmt::Display for Interned<String> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let s: &str = self;
f.write_str(s)
}
}
impl<T, U: ?Sized + fmt::Debug> fmt::Debug for Interned<T>
where
Self: Deref<Target = U>,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let s: &U = self;
f.write_fmt(format_args!("{s:?}"))
}
}
impl<T: Internable + Hash> Hash for Interned<T> {
fn hash<H: Hasher>(&self, state: &mut H) {
let l = T::intern_cache().lock().unwrap();
l.get(*self).hash(state)
}
}
impl<T: Internable + Deref> Deref for Interned<T> {
type Target = T::Target;
fn deref(&self) -> &Self::Target {
let l = T::intern_cache().lock().unwrap();
unsafe { mem::transmute::<&Self::Target, &Self::Target>(l.get(*self)) }
}
}
impl<T: Internable + AsRef<U>, U: ?Sized> AsRef<U> for Interned<T> {
fn as_ref(&self) -> &U {
let l = T::intern_cache().lock().unwrap();
unsafe { mem::transmute::<&U, &U>(l.get(*self).as_ref()) }
}
}
impl<T: Internable + PartialOrd> PartialOrd for Interned<T> {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
let l = T::intern_cache().lock().unwrap();
l.get(*self).partial_cmp(l.get(*other))
}
}
impl<T: Internable + Ord> Ord for Interned<T> {
fn cmp(&self, other: &Self) -> Ordering {
let l = T::intern_cache().lock().unwrap();
l.get(*self).cmp(l.get(*other))
}
}
struct TyIntern<T: Clone + Eq> {
items: Vec<T>,
set: HashMap<T, Interned<T>>,
}
impl<T: Hash + Clone + Eq> Default for TyIntern<T> {
fn default() -> Self {
TyIntern { items: Vec::new(), set: Default::default() }
}
}
impl<T: Hash + Clone + Eq> TyIntern<T> {
fn intern_borrow<B>(&mut self, item: &B) -> Interned<T>
where
B: Eq + Hash + ToOwned<Owned = T> + ?Sized,
T: Borrow<B>,
{
if let Some(i) = self.set.get(item) {
return *i;
}
let item = item.to_owned();
let interned = Interned(self.items.len(), PhantomData::<*const T>);
self.set.insert(item.clone(), interned);
self.items.push(item);
interned
}
fn intern(&mut self, item: T) -> Interned<T> {
if let Some(i) = self.set.get(&item) {
return *i;
}
let interned = Interned(self.items.len(), PhantomData::<*const T>);
self.set.insert(item.clone(), interned);
self.items.push(item);
interned
}
fn get(&self, i: Interned<T>) -> &T {
&self.items[i.0]
}
}
#[derive(Default)]
pub struct Interner {
strs: Mutex<TyIntern<String>>,
paths: Mutex<TyIntern<PathBuf>>,
lists: Mutex<TyIntern<Vec<String>>>,
}
trait Internable: Clone + Eq + Hash + 'static {
fn intern_cache() -> &'static Mutex<TyIntern<Self>>;
fn intern(self) -> Interned<Self> {
Self::intern_cache().lock().unwrap().intern(self)
}
}
impl Internable for String {
fn intern_cache() -> &'static Mutex<TyIntern<Self>> {
&INTERNER.strs
}
}
impl Internable for PathBuf {
fn intern_cache() -> &'static Mutex<TyIntern<Self>> {
&INTERNER.paths
}
}
impl Internable for Vec<String> {
fn intern_cache() -> &'static Mutex<TyIntern<Self>> {
&INTERNER.lists
}
}
impl Interner {
pub fn intern_str(&self, s: &str) -> Interned<String> {
self.strs.lock().unwrap().intern_borrow(s)
}
}
pub static INTERNER: LazyLock<Interner> = LazyLock::new(Interner::default);
#[derive(Debug)]
pub struct Cache(
RefCell<
HashMap<
TypeId,
Box<dyn Any>, >,
>,
);
impl Cache {
pub fn new() -> Cache {
Cache(RefCell::new(HashMap::new()))
}
pub fn put<S: Step>(&self, step: S, value: S::Output) {
let mut cache = self.0.borrow_mut();
let type_id = TypeId::of::<S>();
let stepcache = cache
.entry(type_id)
.or_insert_with(|| Box::<HashMap<S, S::Output>>::default())
.downcast_mut::<HashMap<S, S::Output>>()
.expect("invalid type mapped");
assert!(!stepcache.contains_key(&step), "processing {step:?} a second time");
stepcache.insert(step, value);
}
pub fn get<S: Step>(&self, step: &S) -> Option<S::Output> {
let mut cache = self.0.borrow_mut();
let type_id = TypeId::of::<S>();
let stepcache = cache
.entry(type_id)
.or_insert_with(|| Box::<HashMap<S, S::Output>>::default())
.downcast_mut::<HashMap<S, S::Output>>()
.expect("invalid type mapped");
stepcache.get(step).cloned()
}
}
#[cfg(test)]
impl Cache {
pub fn all<S: Ord + Clone + Step>(&mut self) -> Vec<(S, S::Output)> {
let cache = self.0.get_mut();
let type_id = TypeId::of::<S>();
let mut v = cache
.remove(&type_id)
.map(|b| b.downcast::<HashMap<S, S::Output>>().expect("correct type"))
.map(|m| m.into_iter().collect::<Vec<_>>())
.unwrap_or_default();
v.sort_by_key(|(s, _)| s.clone());
v
}
pub fn contains<S: Step>(&self) -> bool {
self.0.borrow().contains_key(&TypeId::of::<S>())
}
}