Switch to FxHash

Cargo.toml

@@ -45,6 +45,7 @@ mlua_derive = { version = "=0.6.0", optional = true, path = "mlua_derive" }
 bstr = { version = "0.2", features = ["std"], default_features = false }
 once_cell = { version = "1.0" }
 num-traits = { version = "0.2.14" }
+rustc-hash = "1.0"
 futures-core = { version = "0.3.5", optional = true }
 futures-task = { version = "0.3.5", optional = true }
 futures-util = { version = "0.3.5", optional = true }

src/lua.rs

@@ -1,6 +1,5 @@
 use std::any::TypeId;
 use std::cell::{Ref, RefCell, RefMut, UnsafeCell};
-use std::collections::HashMap;
 use std::ffi::CString;
 use std::fmt;
 use std::marker::PhantomData;
@@ -9,6 +8,8 @@ use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe, Location};
 use std::sync::{Arc, Mutex, RwLock};
 use std::{mem, ptr, str};
 
+use rustc_hash::FxHashMap;
+
 use crate::error::{Error, Result};
 use crate::ffi;
 use crate::function::Function;
@@ -63,8 +64,8 @@ pub struct Lua {
 
 // Data associated with the Lua.
 struct ExtraData {
-    registered_userdata: HashMap<TypeId, c_int>,
-    registered_userdata_mt: HashMap<*const c_void, Option<TypeId>>,
+    registered_userdata: FxHashMap<TypeId, c_int>,
+    registered_userdata_mt: FxHashMap<*const c_void, Option<TypeId>>,
     registry_unref_list: Arc<Mutex<Option<Vec<c_int>>>>,
 
     libs: StdLib,
@@ -456,8 +457,8 @@ impl Lua {
         // Create ExtraData
 
         let extra = Arc::new(UnsafeCell::new(ExtraData {
-            registered_userdata: HashMap::new(),
-            registered_userdata_mt: HashMap::new(),
+            registered_userdata: FxHashMap::default(),
+            registered_userdata_mt: FxHashMap::default(),
             registry_unref_list: Arc::new(Mutex::new(Some(Vec::new()))),
             ref_thread,
             libs: StdLib::NONE,
@@ -2425,7 +2426,7 @@ impl<'lua, T: AsRef<[u8]> + ?Sized> AsChunk<'lua> for T {
 }
 
 // Creates required entries in the metatable cache (see `util::METATABLE_CACHE`)
-pub(crate) fn init_metatable_cache(cache: &mut HashMap<TypeId, u8>) {
+pub(crate) fn init_metatable_cache(cache: &mut FxHashMap<TypeId, u8>) {
     cache.insert(TypeId::of::<Arc<UnsafeCell<ExtraData>>>(), 0);
     cache.insert(TypeId::of::<Callback>(), 0);
     cache.insert(TypeId::of::<CallbackUpvalue>(), 0);

src/serde/de.rs

@@ -1,9 +1,9 @@
 use std::cell::RefCell;
-use std::collections::HashSet;
 use std::os::raw::c_void;
 use std::rc::Rc;
 use std::string::String as StdString;
 
+use rustc_hash::FxHashSet;
 use serde::de::{self, IntoDeserializer};
 
 use crate::error::{Error, Result};
@@ -16,7 +16,7 @@ use crate::value::Value;
 pub struct Deserializer<'lua> {
     value: Value<'lua>,
     options: Options,
-    visited: Rc<RefCell<HashSet<*const c_void>>>,
+    visited: Rc<RefCell<FxHashSet<*const c_void>>>,
 }
 
 /// A struct with options to change default deserializer behavior.
@@ -86,14 +86,14 @@ impl<'lua> Deserializer<'lua> {
         Deserializer {
             value,
             options,
-            visited: Rc::new(RefCell::new(HashSet::new())),
+            visited: Rc::new(RefCell::new(FxHashSet::default())),
         }
     }
 
     fn from_parts(
         value: Value<'lua>,
         options: Options,
-        visited: Rc<RefCell<HashSet<*const c_void>>>,
+        visited: Rc<RefCell<FxHashSet<*const c_void>>>,
     ) -> Self {
         Deserializer {
             value,
@@ -313,7 +313,7 @@ impl<'lua, 'de> serde::Deserializer<'de> for Deserializer<'lua> {
 struct SeqDeserializer<'lua> {
     seq: TableSequence<'lua, Value<'lua>>,
     options: Options,
-    visited: Rc<RefCell<HashSet<*const c_void>>>,
+    visited: Rc<RefCell<FxHashSet<*const c_void>>>,
 }
 
 impl<'lua, 'de> de::SeqAccess<'de> for SeqDeserializer<'lua> {
@@ -351,7 +351,7 @@ struct MapDeserializer<'lua> {
     pairs: TablePairs<'lua, Value<'lua>, Value<'lua>>,
     value: Option<Value<'lua>>,
     options: Options,
-    visited: Rc<RefCell<HashSet<*const c_void>>>,
+    visited: Rc<RefCell<FxHashSet<*const c_void>>>,
     processed: usize,
 }
 
@@ -407,7 +407,7 @@ struct EnumDeserializer<'lua> {
     variant: StdString,
     value: Option<Value<'lua>>,
     options: Options,
-    visited: Rc<RefCell<HashSet<*const c_void>>>,
+    visited: Rc<RefCell<FxHashSet<*const c_void>>>,
 }
 
 impl<'lua, 'de> de::EnumAccess<'de> for EnumDeserializer<'lua> {
@@ -431,7 +431,7 @@ impl<'lua, 'de> de::EnumAccess<'de> for EnumDeserializer<'lua> {
 struct VariantDeserializer<'lua> {
     value: Option<Value<'lua>>,
     options: Options,
-    visited: Rc<RefCell<HashSet<*const c_void>>>,
+    visited: Rc<RefCell<FxHashSet<*const c_void>>>,
 }
 
 impl<'lua, 'de> de::VariantAccess<'de> for VariantDeserializer<'lua> {
@@ -499,12 +499,12 @@ impl<'lua, 'de> de::VariantAccess<'de> for VariantDeserializer<'lua> {
 // Used to track recursive tables but allow to traverse same tables multiple times
 struct RecursionGuard {
     ptr: *const c_void,
-    visited: Rc<RefCell<HashSet<*const c_void>>>,
+    visited: Rc<RefCell<FxHashSet<*const c_void>>>,
 }
 
 impl RecursionGuard {
     #[inline]
-    fn new(table: &Table, visited: &Rc<RefCell<HashSet<*const c_void>>>) -> Self {
+    fn new(table: &Table, visited: &Rc<RefCell<FxHashSet<*const c_void>>>) -> Self {
         let visited = Rc::clone(visited);
         let lua = table.0.lua;
         let ptr =
@@ -524,7 +524,7 @@ impl Drop for RecursionGuard {
 fn check_value_if_skip(
     value: &Value,
     options: Options,
-    visited: &RefCell<HashSet<*const c_void>>,
+    visited: &RefCell<FxHashSet<*const c_void>>,
 ) -> Result<bool> {
     match value {
         Value::Table(table) => {

src/util.rs

@@ -1,5 +1,4 @@
 use std::any::{Any, TypeId};
-use std::collections::HashMap;
 use std::error::Error as StdError;
 use std::fmt::Write;
 use std::os::raw::{c_char, c_int, c_void};
@@ -8,12 +7,13 @@ use std::sync::Arc;
 use std::{mem, ptr, slice};
 
 use once_cell::sync::Lazy;
+use rustc_hash::FxHashMap;
 
 use crate::error::{Error, Result};
 use crate::ffi;
 
-static METATABLE_CACHE: Lazy<HashMap<TypeId, u8>> = Lazy::new(|| {
-    let mut map = HashMap::with_capacity(32);
+static METATABLE_CACHE: Lazy<FxHashMap<TypeId, u8>> = Lazy::new(|| {
+    let mut map = FxHashMap::with_capacity_and_hasher(32, Default::default());
     crate::lua::init_metatable_cache(&mut map);
     map.insert(TypeId::of::<WrappedFailure>(), 0);
     map.insert(TypeId::of::<String>(), 0);