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Wrap `ExtraData` to `Arc<UnsafeCell>>` instead of raw pointer and attach finalizer. 

This would allow to properly deallocate memory in module mode when closing lua state.
This commit is contained in:
Alex Orlenko 2021-08-21 23:17:09 +01:00
parent 7d1b322e18
commit 31d32f2dda
No known key found for this signature in database
GPG Key ID: 4C150C250863B96D
2 changed files with 113 additions and 71 deletions
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2
src/hook.rs
View File

@ -32,7 +32,7 @@ impl<'a> Debug<'a> {
/// [Lua 5.1]: https://www.lua.org/manual/5.1/manual.html#pdf-LUA_HOOKTAILRET /// [Lua 5.1]: https://www.lua.org/manual/5.1/manual.html#pdf-LUA_HOOKTAILRET
pub fn event(&self) -> DebugEvent { pub fn event(&self) -> DebugEvent {
unsafe { unsafe {
match (&*self.ar).event { match (*self.ar).event {
ffi::LUA_HOOKCALL => DebugEvent::Call, ffi::LUA_HOOKCALL => DebugEvent::Call,
ffi::LUA_HOOKRET => DebugEvent::Ret, ffi::LUA_HOOKRET => DebugEvent::Ret,
ffi::LUA_HOOKTAILCALL => DebugEvent::TailCall, ffi::LUA_HOOKTAILCALL => DebugEvent::TailCall,

174
src/lua.rs
View File

@ -55,7 +55,7 @@ use serde::Serialize;
pub struct Lua { pub struct Lua {
pub(crate) state: *mut ffi::lua_State, pub(crate) state: *mut ffi::lua_State,
main_state: Option<*mut ffi::lua_State>, main_state: Option<*mut ffi::lua_State>,
extra: *mut ExtraData, extra: Arc<UnsafeCell<ExtraData>>,
ephemeral: bool, ephemeral: bool,
safe: bool, safe: bool,
// Lua has lots of interior mutability, should not be RefUnwindSafe // Lua has lots of interior mutability, should not be RefUnwindSafe
@ -77,8 +77,8 @@ struct ExtraData {
ref_stack_top: c_int, ref_stack_top: c_int,
ref_free: Vec<c_int>, ref_free: Vec<c_int>,
// Vec of preallocated WrappedFailure enums // Vec of preallocated `WrappedFailure` enums
// Used for callback optimization // Used for callbacks optimization
prealloc_wrapped_failures: Vec<c_int>, prealloc_wrapped_failures: Vec<c_int>,
hook_callback: Option<HookCallback>, hook_callback: Option<HookCallback>,
@ -163,7 +163,7 @@ impl Drop for Lua {
fn drop(&mut self) { fn drop(&mut self) {
unsafe { unsafe {
if !self.ephemeral { if !self.ephemeral {
let extra = &mut *self.extra; let extra = &mut *self.extra.get();
for index in extra.prealloc_wrapped_failures.clone() { for index in extra.prealloc_wrapped_failures.clone() {
ffi::lua_pushnil(extra.ref_thread); ffi::lua_pushnil(extra.ref_thread);
ffi::lua_replace(extra.ref_thread, index); ffi::lua_replace(extra.ref_thread, index);
@ -174,14 +174,18 @@ impl Drop for Lua {
&& extra.ref_stack_top as usize == extra.ref_free.len(), && extra.ref_stack_top as usize == extra.ref_free.len(),
"reference leak detected" "reference leak detected"
); );
*mlua_expect!(extra.registry_unref_list.lock(), "unref list poisoned") = None;
ffi::lua_close(mlua_expect!(self.main_state, "main_state is null")); ffi::lua_close(mlua_expect!(self.main_state, "main_state is null"));
Box::from_raw(extra);
} }
} }
} }
} }
impl Drop for ExtraData {
fn drop(&mut self) {
*mlua_expect!(self.registry_unref_list.lock(), "unref list poisoned") = None;
}
}
impl fmt::Debug for Lua { impl fmt::Debug for Lua {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Lua({:p})", self.state) write!(f, "Lua({:p})", self.state)
@ -246,7 +250,7 @@ impl Lua {
mlua_expect!(lua.disable_c_modules(), "Error during disabling C modules"); mlua_expect!(lua.disable_c_modules(), "Error during disabling C modules");
} }
lua.safe = true; lua.safe = true;
unsafe { (*lua.extra).safe = true }; unsafe { (*lua.extra.get()).safe = true };
Ok(lua) Ok(lua)
} }
@ -339,7 +343,7 @@ impl Lua {
let mut lua = Lua::init_from_ptr(state); let mut lua = Lua::init_from_ptr(state);
lua.ephemeral = false; lua.ephemeral = false;
let extra = &mut *lua.extra; let extra = &mut *lua.extra.get();
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))] #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
{ {
@ -391,13 +395,14 @@ impl Lua {
return lua; return lua;
} }
let ref_thread = mlua_expect!( mlua_expect!(
(|state| { (|state| {
init_error_registry(state)?; init_error_registry(state)?;
// Create the internal metatables and place them in the registry // Create the internal metatables and place them in the registry
// to prevent them from being garbage collected. // to prevent them from being garbage collected.
init_gc_metatable::<Arc<UnsafeCell<ExtraData>>>(state, None)?;
init_gc_metatable::<Callback>(state, None)?; init_gc_metatable::<Callback>(state, None)?;
init_gc_metatable::<CallbackUpvalue>(state, None)?; init_gc_metatable::<CallbackUpvalue>(state, None)?;
#[cfg(feature = "async")] #[cfg(feature = "async")]
@ -419,22 +424,25 @@ impl Lua {
#[cfg(feature = "serialize")] #[cfg(feature = "serialize")]
crate::serde::init_metatables(state)?; crate::serde::init_metatables(state)?;
// Create ref stack thread and place it in the registry to prevent it from being garbage Ok::<_, Error>(())
// collected.
let ref_thread = protect_lua(state, 0, 0, |state| {
let thread = ffi::lua_newthread(state);
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX);
thread
})?;
Ok::<_, Error>(ref_thread)
})(main_state), })(main_state),
"Error during Lua construction", "Error during Lua construction",
); );
// Create ref stack thread and place it in the registry to prevent it from being garbage
// collected.
let ref_thread = mlua_expect!(
protect_lua(state, 0, 0, |state| {
let thread = ffi::lua_newthread(state);
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX);
thread
}),
"Error while creating ref thread",
);
// Create ExtraData // Create ExtraData
let extra = Box::into_raw(Box::new(ExtraData { let extra = Arc::new(UnsafeCell::new(ExtraData {
registered_userdata: HashMap::new(), registered_userdata: HashMap::new(),
registered_userdata_mt: HashSet::new(), registered_userdata_mt: HashSet::new(),
registry_unref_list: Arc::new(Mutex::new(Some(Vec::new()))), registry_unref_list: Arc::new(Mutex::new(Some(Vec::new()))),
@ -450,12 +458,14 @@ impl Lua {
hook_callback: None, hook_callback: None,
})); }));
ffi::lua_pushlightuserdata(main_state, extra as *mut c_void);
mlua_expect!( mlua_expect!(
(|state| {
push_gc_userdata(state, Arc::clone(&extra))?;
protect_lua(main_state, 1, 0, |state| { protect_lua(main_state, 1, 0, |state| {
let extra_key = &EXTRA_REGISTRY_KEY as *const u8 as *const c_void; let extra_key = &EXTRA_REGISTRY_KEY as *const u8 as *const c_void;
ffi::lua_rawsetp(state, ffi::LUA_REGISTRYINDEX, extra_key) ffi::lua_rawsetp(state, ffi::LUA_REGISTRYINDEX, extra_key);
}), })
})(main_state),
"Error while storing extra data", "Error while storing extra data",
); );
@ -499,7 +509,7 @@ impl Lua {
let res = unsafe { load_from_std_lib(state, libs) }; let res = unsafe { load_from_std_lib(state, libs) };
// If `package` library loaded into a safe lua state then disable C modules // If `package` library loaded into a safe lua state then disable C modules
let extra = unsafe { &mut *self.extra }; let extra = unsafe { &mut *self.extra.get() };
let curr_libs = extra.libs; let curr_libs = extra.libs;
if self.safe && (curr_libs ^ (curr_libs | libs)).contains(StdLib::PACKAGE) { if self.safe && (curr_libs ^ (curr_libs | libs)).contains(StdLib::PACKAGE) {
mlua_expect!(self.disable_c_modules(), "Error during disabling C modules"); mlua_expect!(self.disable_c_modules(), "Error during disabling C modules");
@ -582,29 +592,57 @@ impl Lua {
} }
// Executes module entrypoint function, which returns only one Value. // Executes module entrypoint function, which returns only one Value.
// The returned value then pushed to the Lua stack. // The returned value then pushed onto the stack.
#[doc(hidden)] #[doc(hidden)]
#[cfg(not(tarpaulin_include))] #[cfg(not(tarpaulin_include))]
pub fn entrypoint1<'lua, 'callback, R, F>(&'lua self, func: F) -> Result<c_int> pub unsafe fn entrypoint<'lua, A, R, F>(self, func: F) -> Result<c_int>
where where
'lua: 'callback, A: FromLuaMulti<'lua>,
R: ToLua<'callback>, R: ToLua<'lua>,
F: 'static + MaybeSend + Fn(&'callback Lua) -> Result<R>, F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>,
{ {
let cb = self.create_callback(Box::new(move |lua, _| func(lua)?.to_lua_multi(lua)))?; let entrypoint_inner = |lua: &'lua Lua, func: F| {
let res = cb.call(()); let nargs = ffi::lua_gettop(lua.state);
unsafe { check_stack(lua.state, 3)?;
check_stack(self.state, 2)?;
match res { let mut args = MultiValue::new();
Ok(res) => self.push_value(res)?, args.reserve(nargs as usize);
for _ in 0..nargs {
args.push_front(lua.pop_value());
}
// We create callback rather than call `func` directly to catch errors
// with attached stacktrace.
let callback = lua.create_callback(Box::new(move |lua, args| {
func(lua, A::from_lua_multi(args, lua)?)?.to_lua_multi(lua)
}))?;
callback.call(args)
};
match entrypoint_inner(mem::transmute(&self), func) {
Ok(res) => {
self.push_value(res)?;
Ok(1)
}
Err(err) => { Err(err) => {
self.push_value(Value::Error(err))?; self.push_value(Value::Error(err))?;
// This longjmp is undesired, but we cannot wrap it to a C let state = self.state;
ffi::lua_error(self.state) // Lua (self) must be dropped before triggering longjmp
drop(self);
ffi::lua_error(state)
} }
} }
}; }
Ok(1)
// A simple module entrypoint without arguments
#[doc(hidden)]
#[cfg(not(tarpaulin_include))]
pub unsafe fn entrypoint1<'lua, R, F>(self, func: F) -> Result<c_int>
where
R: ToLua<'lua>,
F: 'static + MaybeSend + Fn(&'lua Lua) -> Result<R>,
{
self.entrypoint(move |lua, _: ()| func(lua))
} }
/// Sets a 'hook' function that will periodically be called as Lua code executes. /// Sets a 'hook' function that will periodically be called as Lua code executes.
@ -646,7 +684,7 @@ impl Lua {
{ {
let state = self.main_state.ok_or(Error::MainThreadNotAvailable)?; let state = self.main_state.ok_or(Error::MainThreadNotAvailable)?;
unsafe { unsafe {
(*self.extra).hook_callback = Some(Arc::new(RefCell::new(callback))); (*self.extra.get()).hook_callback = Some(Arc::new(RefCell::new(callback)));
ffi::lua_sethook(state, Some(hook_proc), triggers.mask(), triggers.count()); ffi::lua_sethook(state, Some(hook_proc), triggers.mask(), triggers.count());
} }
Ok(()) Ok(())
@ -661,7 +699,7 @@ impl Lua {
None => return, None => return,
}; };
unsafe { unsafe {
(*self.extra).hook_callback = None; (*self.extra.get()).hook_callback = None;
ffi::lua_sethook(state, None, 0, 0); ffi::lua_sethook(state, None, 0, 0);
} }
} }
@ -670,7 +708,7 @@ impl Lua {
pub fn used_memory(&self) -> usize { pub fn used_memory(&self) -> usize {
unsafe { unsafe {
let state = self.main_state.unwrap_or(self.state); let state = self.main_state.unwrap_or(self.state);
match &(*self.extra).mem_info { match &(*self.extra.get()).mem_info {
Some(mem_info) => mem_info.used_memory as usize, Some(mem_info) => mem_info.used_memory as usize,
None => { None => {
// Get data from the Lua GC // Get data from the Lua GC
@ -694,7 +732,7 @@ impl Lua {
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", doc))] #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", doc))]
pub fn set_memory_limit(&self, memory_limit: usize) -> Result<usize> { pub fn set_memory_limit(&self, memory_limit: usize) -> Result<usize> {
unsafe { unsafe {
match &mut (*self.extra).mem_info { match &mut (*self.extra.get()).mem_info {
Some(mem_info) => { Some(mem_info) => {
let prev_limit = mem_info.memory_limit as usize; let prev_limit = mem_info.memory_limit as usize;
mem_info.memory_limit = memory_limit as isize; mem_info.memory_limit = memory_limit as isize;
@ -1434,7 +1472,7 @@ impl Lua {
Ok(RegistryKey { Ok(RegistryKey {
registry_id, registry_id,
unref_list: (*self.extra).registry_unref_list.clone(), unref_list: (*self.extra.get()).registry_unref_list.clone(),
}) })
} }
} }
@ -1490,7 +1528,7 @@ impl Lua {
/// `Error::MismatchedRegistryKey` if passed a `RegistryKey` that was not created with a /// `Error::MismatchedRegistryKey` if passed a `RegistryKey` that was not created with a
/// matching `Lua` state. /// matching `Lua` state.
pub fn owns_registry_value(&self, key: &RegistryKey) -> bool { pub fn owns_registry_value(&self, key: &RegistryKey) -> bool {
let registry_unref_list = unsafe { &(*self.extra).registry_unref_list }; let registry_unref_list = unsafe { &(*self.extra.get()).registry_unref_list };
Arc::ptr_eq(&key.unref_list, registry_unref_list) Arc::ptr_eq(&key.unref_list, registry_unref_list)
} }
@ -1502,7 +1540,7 @@ impl Lua {
pub fn expire_registry_values(&self) { pub fn expire_registry_values(&self) {
unsafe { unsafe {
let mut unref_list = mlua_expect!( let mut unref_list = mlua_expect!(
(*self.extra).registry_unref_list.lock(), (*self.extra.get()).registry_unref_list.lock(),
"unref list poisoned" "unref list poisoned"
); );
let unref_list = mem::replace(&mut *unref_list, Some(Vec::new())); let unref_list = mem::replace(&mut *unref_list, Some(Vec::new()));
@ -1633,11 +1671,12 @@ impl Lua {
// Pushes a LuaRef value onto the stack, uses 1 stack space, does not call checkstack // Pushes a LuaRef value onto the stack, uses 1 stack space, does not call checkstack
pub(crate) unsafe fn push_ref<'lua>(&'lua self, lref: &LuaRef<'lua>) { pub(crate) unsafe fn push_ref<'lua>(&'lua self, lref: &LuaRef<'lua>) {
assert!( assert!(
lref.lua.extra == self.extra, Arc::ptr_eq(&lref.lua.extra, &self.extra),
"Lua instance passed Value created from a different main Lua state" "Lua instance passed Value created from a different main Lua state"
); );
ffi::lua_pushvalue((*self.extra).ref_thread, lref.index); let extra = &*self.extra.get();
ffi::lua_xmove((*self.extra).ref_thread, self.state, 1); ffi::lua_pushvalue(extra.ref_thread, lref.index);
ffi::lua_xmove(extra.ref_thread, self.state, 1);
} }
// Pops the topmost element of the stack and stores a reference to it. This pins the object, // Pops the topmost element of the stack and stores a reference to it. This pins the object,
@ -1650,7 +1689,7 @@ impl Lua {
// number of short term references being created, and `RegistryKey` being used for long term // number of short term references being created, and `RegistryKey` being used for long term
// references. // references.
pub(crate) unsafe fn pop_ref(&self) -> LuaRef { pub(crate) unsafe fn pop_ref(&self) -> LuaRef {
let extra = &mut *self.extra; let extra = &mut *self.extra.get();
ffi::lua_xmove(self.state, extra.ref_thread, 1); ffi::lua_xmove(self.state, extra.ref_thread, 1);
let index = ref_stack_pop(extra); let index = ref_stack_pop(extra);
LuaRef { lua: self, index } LuaRef { lua: self, index }
@ -1658,7 +1697,7 @@ impl Lua {
pub(crate) fn clone_ref<'lua>(&'lua self, lref: &LuaRef<'lua>) -> LuaRef<'lua> { pub(crate) fn clone_ref<'lua>(&'lua self, lref: &LuaRef<'lua>) -> LuaRef<'lua> {
unsafe { unsafe {
let extra = &mut *self.extra; let extra = &mut *self.extra.get();
ffi::lua_pushvalue(extra.ref_thread, lref.index); ffi::lua_pushvalue(extra.ref_thread, lref.index);
let index = ref_stack_pop(extra); let index = ref_stack_pop(extra);
LuaRef { lua: self, index } LuaRef { lua: self, index }
@ -1667,7 +1706,7 @@ impl Lua {
pub(crate) fn drop_ref<'lua>(&'lua self, lref: &mut LuaRef<'lua>) { pub(crate) fn drop_ref<'lua>(&'lua self, lref: &mut LuaRef<'lua>) {
unsafe { unsafe {
let extra = &mut *self.extra; let extra = &mut *self.extra.get();
ffi::lua_pushnil(extra.ref_thread); ffi::lua_pushnil(extra.ref_thread);
ffi::lua_replace(extra.ref_thread, lref.index); ffi::lua_replace(extra.ref_thread, lref.index);
extra.ref_free.push(lref.index); extra.ref_free.push(lref.index);
@ -1675,8 +1714,10 @@ impl Lua {
} }
pub(crate) unsafe fn push_userdata_metatable<T: 'static + UserData>(&self) -> Result<()> { pub(crate) unsafe fn push_userdata_metatable<T: 'static + UserData>(&self) -> Result<()> {
let extra = &mut *self.extra.get();
let type_id = TypeId::of::<T>(); let type_id = TypeId::of::<T>();
if let Some(&table_id) = (*self.extra).registered_userdata.get(&type_id) { if let Some(&table_id) = extra.registered_userdata.get(&type_id) {
ffi::lua_rawgeti(self.state, ffi::LUA_REGISTRYINDEX, table_id as Integer); ffi::lua_rawgeti(self.state, ffi::LUA_REGISTRYINDEX, table_id as Integer);
return Ok(()); return Ok(());
} }
@ -1771,7 +1812,6 @@ impl Lua {
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX) ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX)
})?; })?;
let extra = &mut *self.extra;
extra.registered_userdata.insert(type_id, id); extra.registered_userdata.insert(type_id, id);
extra.registered_userdata_mt.insert(ptr as isize); extra.registered_userdata_mt.insert(ptr as isize);
@ -1779,11 +1819,11 @@ impl Lua {
} }
pub(crate) unsafe fn register_userdata_metatable(&self, id: isize) { pub(crate) unsafe fn register_userdata_metatable(&self, id: isize) {
(*self.extra).registered_userdata_mt.insert(id); (*self.extra.get()).registered_userdata_mt.insert(id);
} }
pub(crate) unsafe fn deregister_userdata_metatable(&self, id: isize) { pub(crate) unsafe fn deregister_userdata_metatable(&self, id: isize) {
(*self.extra).registered_userdata_mt.remove(&id); (*self.extra.get()).registered_userdata_mt.remove(&id);
} }
// Pushes a LuaRef value onto the stack, checking that it's a registered // Pushes a LuaRef value onto the stack, checking that it's a registered
@ -1796,7 +1836,7 @@ impl Lua {
} }
// Check that userdata is registered // Check that userdata is registered
let ptr = ffi::lua_topointer(self.state, -1); let ptr = ffi::lua_topointer(self.state, -1);
let extra = &*self.extra; let extra = &*self.extra.get();
if extra.registered_userdata_mt.contains(&(ptr as isize)) { if extra.registered_userdata_mt.contains(&(ptr as isize)) {
if !with_mt { if !with_mt {
ffi::lua_pop(self.state, 1); ffi::lua_pop(self.state, 1);
@ -1831,7 +1871,7 @@ impl Lua {
unsafe extern "C" fn call_callback(state: *mut ffi::lua_State) -> c_int { unsafe extern "C" fn call_callback(state: *mut ffi::lua_State) -> c_int {
let get_extra = |state| { let get_extra = |state| {
let upvalue = get_userdata::<CallbackUpvalue>(state, ffi::lua_upvalueindex(1)); let upvalue = get_userdata::<CallbackUpvalue>(state, ffi::lua_upvalueindex(1));
(*upvalue).lua.extra (*upvalue).lua.extra.get()
}; };
callback_error_ext(state, get_extra, |nargs| { callback_error_ext(state, get_extra, |nargs| {
let upvalue_idx = ffi::lua_upvalueindex(1); let upvalue_idx = ffi::lua_upvalueindex(1);
@ -1889,8 +1929,8 @@ impl Lua {
'lua: 'callback, 'lua: 'callback,
{ {
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))] #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
{ unsafe {
let libs = unsafe { (*self.extra).libs }; let libs = (*self.extra.get()).libs;
if !libs.contains(StdLib::COROUTINE) { if !libs.contains(StdLib::COROUTINE) {
self.load_from_std_lib(StdLib::COROUTINE)?; self.load_from_std_lib(StdLib::COROUTINE)?;
} }
@ -1899,7 +1939,7 @@ impl Lua {
unsafe extern "C" fn call_callback(state: *mut ffi::lua_State) -> c_int { unsafe extern "C" fn call_callback(state: *mut ffi::lua_State) -> c_int {
let get_extra = |state| { let get_extra = |state| {
let upvalue = get_userdata::<AsyncCallbackUpvalue>(state, ffi::lua_upvalueindex(1)); let upvalue = get_userdata::<AsyncCallbackUpvalue>(state, ffi::lua_upvalueindex(1));
(*upvalue).lua.extra (*upvalue).lua.extra.get()
}; };
callback_error_ext(state, get_extra, |nargs| { callback_error_ext(state, get_extra, |nargs| {
let upvalue_idx = ffi::lua_upvalueindex(1); let upvalue_idx = ffi::lua_upvalueindex(1);
@ -1935,7 +1975,7 @@ impl Lua {
unsafe extern "C" fn poll_future(state: *mut ffi::lua_State) -> c_int { unsafe extern "C" fn poll_future(state: *mut ffi::lua_State) -> c_int {
let get_extra = |state| { let get_extra = |state| {
let upvalue = get_userdata::<AsyncPollUpvalue>(state, ffi::lua_upvalueindex(1)); let upvalue = get_userdata::<AsyncPollUpvalue>(state, ffi::lua_upvalueindex(1));
(*upvalue).lua.extra (*upvalue).lua.extra.get()
}; };
callback_error_ext(state, get_extra, |nargs| { callback_error_ext(state, get_extra, |nargs| {
let upvalue_idx = ffi::lua_upvalueindex(1); let upvalue_idx = ffi::lua_upvalueindex(1);
@ -2054,7 +2094,7 @@ impl Lua {
Lua { Lua {
state: self.state, state: self.state,
main_state: self.main_state, main_state: self.main_state,
extra: self.extra, extra: Arc::clone(&self.extra),
ephemeral: true, ephemeral: true,
safe: self.safe, safe: self.safe,
_no_ref_unwind_safe: PhantomData, _no_ref_unwind_safe: PhantomData,
@ -2092,24 +2132,26 @@ impl Lua {
assert_stack(state, 1); assert_stack(state, 1);
let extra_key = &EXTRA_REGISTRY_KEY as *const u8 as *const c_void; let extra_key = &EXTRA_REGISTRY_KEY as *const u8 as *const c_void;
if ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, extra_key) != ffi::LUA_TLIGHTUSERDATA { if ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, extra_key) != ffi::LUA_TUSERDATA {
return None; return None;
} }
let extra = ffi::lua_touserdata(state, -1) as *mut ExtraData; let extra_ptr = ffi::lua_touserdata(state, -1) as *mut Arc<UnsafeCell<ExtraData>>;
let extra = Arc::clone(&*extra_ptr);
ffi::lua_pop(state, 1); ffi::lua_pop(state, 1);
let safe = (*extra.get()).safe;
Some(Lua { Some(Lua {
state, state,
main_state: get_main_state(state), main_state: get_main_state(state),
extra, extra,
ephemeral: true, ephemeral: true,
safe: (*extra).safe, safe,
_no_ref_unwind_safe: PhantomData, _no_ref_unwind_safe: PhantomData,
}) })
} }
pub(crate) unsafe fn hook_callback(&self) -> Option<HookCallback> { pub(crate) unsafe fn hook_callback(&self) -> Option<HookCallback> {
(*self.extra).hook_callback.clone() (*self.extra.get()).hook_callback.clone()
} }
} }