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

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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
pub fn event(&self) -> DebugEvent {
unsafe {
match (&*self.ar).event {
match (*self.ar).event {
ffi::LUA_HOOKCALL => DebugEvent::Call,
ffi::LUA_HOOKRET => DebugEvent::Ret,
ffi::LUA_HOOKTAILCALL => DebugEvent::TailCall,

182
src/lua.rs
View file

@ -55,7 +55,7 @@ use serde::Serialize;
pub struct Lua {
pub(crate) state: *mut ffi::lua_State,
main_state: Option<*mut ffi::lua_State>,
extra: *mut ExtraData,
extra: Arc<UnsafeCell<ExtraData>>,
ephemeral: bool,
safe: bool,
// Lua has lots of interior mutability, should not be RefUnwindSafe
@ -77,8 +77,8 @@ struct ExtraData {
ref_stack_top: c_int,
ref_free: Vec<c_int>,
// Vec of preallocated WrappedFailure enums
// Used for callback optimization
// Vec of preallocated `WrappedFailure` enums
// Used for callbacks optimization
prealloc_wrapped_failures: Vec<c_int>,
hook_callback: Option<HookCallback>,
@ -163,7 +163,7 @@ impl Drop for Lua {
fn drop(&mut self) {
unsafe {
if !self.ephemeral {
let extra = &mut *self.extra;
let extra = &mut *self.extra.get();
for index in extra.prealloc_wrapped_failures.clone() {
ffi::lua_pushnil(extra.ref_thread);
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(),
"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"));
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 {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Lua({:p})", self.state)
@ -246,7 +250,7 @@ impl Lua {
mlua_expect!(lua.disable_c_modules(), "Error during disabling C modules");
}
lua.safe = true;
unsafe { (*lua.extra).safe = true };
unsafe { (*lua.extra.get()).safe = true };
Ok(lua)
}
@ -339,7 +343,7 @@ impl Lua {
let mut lua = Lua::init_from_ptr(state);
lua.ephemeral = false;
let extra = &mut *lua.extra;
let extra = &mut *lua.extra.get();
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
{
@ -391,13 +395,14 @@ impl Lua {
return lua;
}
let ref_thread = mlua_expect!(
mlua_expect!(
(|state| {
init_error_registry(state)?;
// Create the internal metatables and place them in the registry
// to prevent them from being garbage collected.
init_gc_metatable::<Arc<UnsafeCell<ExtraData>>>(state, None)?;
init_gc_metatable::<Callback>(state, None)?;
init_gc_metatable::<CallbackUpvalue>(state, None)?;
#[cfg(feature = "async")]
@ -419,22 +424,25 @@ impl Lua {
#[cfg(feature = "serialize")]
crate::serde::init_metatables(state)?;
// Create ref stack thread and place it in the registry to prevent it from being garbage
// 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)
Ok::<_, Error>(())
})(main_state),
"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
let extra = Box::into_raw(Box::new(ExtraData {
let extra = Arc::new(UnsafeCell::new(ExtraData {
registered_userdata: HashMap::new(),
registered_userdata_mt: HashSet::new(),
registry_unref_list: Arc::new(Mutex::new(Some(Vec::new()))),
@ -450,12 +458,14 @@ impl Lua {
hook_callback: None,
}));
ffi::lua_pushlightuserdata(main_state, extra as *mut c_void);
mlua_expect!(
protect_lua(main_state, 1, 0, |state| {
let extra_key = &EXTRA_REGISTRY_KEY as *const u8 as *const c_void;
ffi::lua_rawsetp(state, ffi::LUA_REGISTRYINDEX, extra_key)
}),
(|state| {
push_gc_userdata(state, Arc::clone(&extra))?;
protect_lua(main_state, 1, 0, |state| {
let extra_key = &EXTRA_REGISTRY_KEY as *const u8 as *const c_void;
ffi::lua_rawsetp(state, ffi::LUA_REGISTRYINDEX, extra_key);
})
})(main_state),
"Error while storing extra data",
);
@ -499,7 +509,7 @@ impl Lua {
let res = unsafe { load_from_std_lib(state, libs) };
// 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;
if self.safe && (curr_libs ^ (curr_libs | libs)).contains(StdLib::PACKAGE) {
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.
// The returned value then pushed to the Lua stack.
// The returned value then pushed onto the stack.
#[doc(hidden)]
#[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
'lua: 'callback,
R: ToLua<'callback>,
F: 'static + MaybeSend + Fn(&'callback Lua) -> Result<R>,
A: FromLuaMulti<'lua>,
R: ToLua<'lua>,
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 res = cb.call(());
unsafe {
check_stack(self.state, 2)?;
match res {
Ok(res) => self.push_value(res)?,
Err(err) => {
self.push_value(Value::Error(err))?;
// This longjmp is undesired, but we cannot wrap it to a C
ffi::lua_error(self.state)
}
let entrypoint_inner = |lua: &'lua Lua, func: F| {
let nargs = ffi::lua_gettop(lua.state);
check_stack(lua.state, 3)?;
let mut args = MultiValue::new();
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)
};
Ok(1)
match entrypoint_inner(mem::transmute(&self), func) {
Ok(res) => {
self.push_value(res)?;
Ok(1)
}
Err(err) => {
self.push_value(Value::Error(err))?;
let state = self.state;
// Lua (self) must be dropped before triggering longjmp
drop(self);
ffi::lua_error(state)
}
}
}
// 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.
@ -646,7 +684,7 @@ impl Lua {
{
let state = self.main_state.ok_or(Error::MainThreadNotAvailable)?;
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());
}
Ok(())
@ -661,7 +699,7 @@ impl Lua {
None => return,
};
unsafe {
(*self.extra).hook_callback = None;
(*self.extra.get()).hook_callback = None;
ffi::lua_sethook(state, None, 0, 0);
}
}
@ -670,7 +708,7 @@ impl Lua {
pub fn used_memory(&self) -> usize {
unsafe {
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,
None => {
// Get data from the Lua GC
@ -694,7 +732,7 @@ impl Lua {
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", doc))]
pub fn set_memory_limit(&self, memory_limit: usize) -> Result<usize> {
unsafe {
match &mut (*self.extra).mem_info {
match &mut (*self.extra.get()).mem_info {
Some(mem_info) => {
let prev_limit = mem_info.memory_limit as usize;
mem_info.memory_limit = memory_limit as isize;
@ -1434,7 +1472,7 @@ impl Lua {
Ok(RegistryKey {
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
/// matching `Lua` state.
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)
}
@ -1502,7 +1540,7 @@ impl Lua {
pub fn expire_registry_values(&self) {
unsafe {
let mut unref_list = mlua_expect!(
(*self.extra).registry_unref_list.lock(),
(*self.extra.get()).registry_unref_list.lock(),
"unref list poisoned"
);
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
pub(crate) unsafe fn push_ref<'lua>(&'lua self, lref: &LuaRef<'lua>) {
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"
);
ffi::lua_pushvalue((*self.extra).ref_thread, lref.index);
ffi::lua_xmove((*self.extra).ref_thread, self.state, 1);
let extra = &*self.extra.get();
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,
@ -1650,7 +1689,7 @@ impl Lua {
// number of short term references being created, and `RegistryKey` being used for long term
// references.
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);
let index = ref_stack_pop(extra);
LuaRef { lua: self, index }
@ -1658,7 +1697,7 @@ impl Lua {
pub(crate) fn clone_ref<'lua>(&'lua self, lref: &LuaRef<'lua>) -> LuaRef<'lua> {
unsafe {
let extra = &mut *self.extra;
let extra = &mut *self.extra.get();
ffi::lua_pushvalue(extra.ref_thread, lref.index);
let index = ref_stack_pop(extra);
LuaRef { lua: self, index }
@ -1667,7 +1706,7 @@ impl Lua {
pub(crate) fn drop_ref<'lua>(&'lua self, lref: &mut LuaRef<'lua>) {
unsafe {
let extra = &mut *self.extra;
let extra = &mut *self.extra.get();
ffi::lua_pushnil(extra.ref_thread);
ffi::lua_replace(extra.ref_thread, 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<()> {
let extra = &mut *self.extra.get();
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);
return Ok(());
}
@ -1771,7 +1812,6 @@ impl Lua {
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX)
})?;
let extra = &mut *self.extra;
extra.registered_userdata.insert(type_id, id);
extra.registered_userdata_mt.insert(ptr as isize);
@ -1779,11 +1819,11 @@ impl Lua {
}
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) {
(*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
@ -1796,7 +1836,7 @@ impl Lua {
}
// Check that userdata is registered
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 !with_mt {
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 {
let get_extra = |state| {
let upvalue = get_userdata::<CallbackUpvalue>(state, ffi::lua_upvalueindex(1));
(*upvalue).lua.extra
(*upvalue).lua.extra.get()
};
callback_error_ext(state, get_extra, |nargs| {
let upvalue_idx = ffi::lua_upvalueindex(1);
@ -1889,8 +1929,8 @@ impl Lua {
'lua: 'callback,
{
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
{
let libs = unsafe { (*self.extra).libs };
unsafe {
let libs = (*self.extra.get()).libs;
if !libs.contains(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 {
let get_extra = |state| {
let upvalue = get_userdata::<AsyncCallbackUpvalue>(state, ffi::lua_upvalueindex(1));
(*upvalue).lua.extra
(*upvalue).lua.extra.get()
};
callback_error_ext(state, get_extra, |nargs| {
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 {
let get_extra = |state| {
let upvalue = get_userdata::<AsyncPollUpvalue>(state, ffi::lua_upvalueindex(1));
(*upvalue).lua.extra
(*upvalue).lua.extra.get()
};
callback_error_ext(state, get_extra, |nargs| {
let upvalue_idx = ffi::lua_upvalueindex(1);
@ -2054,7 +2094,7 @@ impl Lua {
Lua {
state: self.state,
main_state: self.main_state,
extra: self.extra,
extra: Arc::clone(&self.extra),
ephemeral: true,
safe: self.safe,
_no_ref_unwind_safe: PhantomData,
@ -2092,24 +2132,26 @@ impl Lua {
assert_stack(state, 1);
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;
}
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);
let safe = (*extra.get()).safe;
Some(Lua {
state,
main_state: get_main_state(state),
extra,
ephemeral: true,
safe: (*extra).safe,
safe,
_no_ref_unwind_safe: PhantomData,
})
}
pub(crate) unsafe fn hook_callback(&self) -> Option<HookCallback> {
(*self.extra).hook_callback.clone()
(*self.extra.get()).hook_callback.clone()
}
}