v0.3.0-alpha.1 with async support

Squashed commit of the async branch.

1 files changed, 16 insertions, 12 deletions

diff --git a/src/types.rs b/src/types.rs
index e88d0c1..38065bc 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -1,7 +1,11 @@
+use std::cell::RefCell;
 use std::os::raw::{c_int, c_void};
-use std::sync::{Arc, Mutex};
+use std::rc::Rc;
 use std::{fmt, mem, ptr};
 
+#[cfg(feature = "async")]
+use futures_core::future::LocalBoxFuture;
+
 use crate::error::Result;
 use crate::ffi;
 use crate::lua::Lua;
@@ -20,29 +24,28 @@ pub struct LightUserData(pub *mut c_void);
 pub(crate) type Callback<'lua, 'a> =
     Box<dyn Fn(&'lua Lua, MultiValue<'lua>) -> Result<MultiValue<'lua>> + 'a>;
 
+#[cfg(feature = "async")]
+pub(crate) type AsyncCallback<'lua, 'a> =
+    Box<dyn Fn(&'lua Lua, MultiValue<'lua>) -> LocalBoxFuture<'lua, Result<MultiValue<'lua>>> + 'a>;
+
 /// An auto generated key into the Lua registry.
 ///
-/// This is a handle to a value stored inside the Lua registry.  It is not directly usable like the
-/// `Table` or `Function` handle types, but since it doesn't hold a reference to a parent Lua and is
-/// Send + Sync + 'static, it is much more flexible and can be used in many situations where it is
-/// impossible to directly store a normal handle type.  It is not automatically garbage collected on
-/// Drop, but it can be removed with [`Lua::remove_registry_value`], and instances not manually
-/// removed can be garbage collected with [`Lua::expire_registry_values`].
+/// This is a handle to a value stored inside the Lua registry.  It is not automatically
+/// garbage collected on Drop, but it can be removed with [`Lua::remove_registry_value`],
+/// and instances not manually removed can be garbage collected with [`Lua::expire_registry_values`].
 ///
 /// Be warned, If you place this into Lua via a `UserData` type or a rust callback, it is *very
 /// easy* to accidentally cause reference cycles that the Lua garbage collector cannot resolve.
 /// Instead of placing a `RegistryKey` into a `UserData` type, prefer instead to use
-/// [`UserData::set_user_value`] / [`UserData::get_user_value`], and instead of moving a RegistryKey
-/// into a callback, prefer [`Lua::scope`].
+/// [`UserData::set_user_value`] / [`UserData::get_user_value`].
 ///
 /// [`Lua::remove_registry_value`]: struct.Lua.html#method.remove_registry_value
 /// [`Lua::expire_registry_values`]: struct.Lua.html#method.expire_registry_values
-/// [`Lua::scope`]: struct.Lua.html#method.scope
 /// [`UserData::set_user_value`]: struct.UserData.html#method.set_user_value
 /// [`UserData::get_user_value`]: struct.UserData.html#method.get_user_value
 pub struct RegistryKey {
     pub(crate) registry_id: c_int,
-    pub(crate) unref_list: Arc<Mutex<Option<Vec<c_int>>>>,
+    pub(crate) unref_list: Rc<RefCell<Option<Vec<c_int>>>>,
 }
 
 impl fmt::Debug for RegistryKey {
@@ -53,7 +56,8 @@ impl fmt::Debug for RegistryKey {
 
 impl Drop for RegistryKey {
     fn drop(&mut self) {
-        if let Some(list) = mlua_expect!(self.unref_list.lock(), "unref_list poisoned").as_mut() {
+        let mut unref_list = mlua_expect!(self.unref_list.try_borrow_mut(), "unref list borrowed");
+        if let Some(list) = unref_list.as_mut() {
             list.push(self.registry_id);
         }
     }