use std::borrow::Borrow;
use std::hash::{Hash, Hasher};
use std::sync::atomic::{AtomicU32, Ordering};
use std::sync::{Mutex, MutexGuard};
use std::time::{SystemTime, UNIX_EPOCH};
use ahash::RandomState;
use once_cell::sync::Lazy;
use smartstring::{LazyCompact, SmartString};
use crate::frame::groupby::hashing::HASHMAP_INIT_SIZE;
use crate::prelude::PlHashMap;
pub(crate) static USE_STRING_CACHE: AtomicU32 = AtomicU32::new(0);
pub struct IUseStringCache {
#[allow(dead_code)]
private_zst: (),
}
impl Default for IUseStringCache {
fn default() -> Self {
Self::new()
}
}
impl IUseStringCache {
pub fn new() -> IUseStringCache {
toggle_string_cache(true);
IUseStringCache { private_zst: () }
}
}
impl Drop for IUseStringCache {
fn drop(&mut self) {
toggle_string_cache(false)
}
}
pub fn with_string_cache<F: FnOnce() -> T, T>(func: F) -> T {
toggle_string_cache(true);
let out = func();
toggle_string_cache(false);
out
}
pub fn toggle_string_cache(toggle: bool) {
if toggle {
USE_STRING_CACHE.fetch_add(1, Ordering::Release);
} else {
let previous = USE_STRING_CACHE.fetch_sub(1, Ordering::Release);
if previous == 0 || previous == 1 {
USE_STRING_CACHE.store(0, Ordering::Release);
STRING_CACHE.clear()
}
}
}
pub fn reset_string_cache() {
USE_STRING_CACHE.store(0, Ordering::Release);
STRING_CACHE.clear()
}
pub fn using_string_cache() -> bool {
USE_STRING_CACHE.load(Ordering::Acquire) > 0
}
pub(crate) struct SCacheInner {
pub(crate) map: PlHashMap<StrHashGlobal, u32>,
pub(crate) uuid: u128,
}
impl Default for SCacheInner {
fn default() -> Self {
Self {
map: PlHashMap::with_capacity_and_hasher(
HASHMAP_INIT_SIZE,
StringCache::get_hash_builder(),
),
uuid: SystemTime::now()
.duration_since(UNIX_EPOCH)
.unwrap()
.as_nanos(),
}
}
}
pub(crate) struct StringCache(pub(crate) Mutex<SCacheInner>);
impl StringCache {
pub(crate) fn get_hash_builder() -> RandomState {
RandomState::with_seed(0)
}
pub(crate) fn lock_map(&self) -> MutexGuard<SCacheInner> {
self.0.lock().unwrap()
}
pub(crate) fn clear(&self) {
let mut lock = self.lock_map();
*lock = Default::default();
}
}
impl Default for StringCache {
fn default() -> Self {
StringCache(Mutex::new(Default::default()))
}
}
pub(crate) static STRING_CACHE: Lazy<StringCache> = Lazy::new(Default::default);
#[derive(Eq, Clone)]
pub struct StrHashGlobal {
pub(crate) str: SmartString<LazyCompact>,
pub(crate) hash: u64,
}
impl Hash for StrHashGlobal {
fn hash<H: Hasher>(&self, state: &mut H) {
state.write_u64(self.hash)
}
}
impl StrHashGlobal {
pub(crate) fn new(s: SmartString<LazyCompact>, hash: u64) -> Self {
Self { str: s, hash }
}
}
impl PartialEq for StrHashGlobal {
fn eq(&self, other: &Self) -> bool {
(self.hash == other.hash) && (self.str == other.str)
}
}
impl Borrow<str> for StrHashGlobal {
fn borrow(&self) -> &str {
self.str.as_str()
}
}