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Store nonstatic UserData pointer in self userdata (instead of metatable)

This commit is contained in:
Alex Orlenko 2021-04-27 12:58:25 +01:00
parent 0625991a48
commit b5f1325f2f
2 changed files with 30 additions and 35 deletions
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57
src/scope.rs
View File

@ -2,8 +2,7 @@ use std::any::Any;
use std::cell::{Cell, Ref, RefCell, RefMut};
use std::marker::PhantomData;
use std::mem;
use std::os::raw::{c_int, c_void};
use std::rc::Rc;
use std::os::raw::c_int;
#[cfg(feature = "serialize")]
use serde::Serialize;
@ -17,7 +16,7 @@ use crate::userdata::{
AnyUserData, MetaMethod, UserData, UserDataFields, UserDataMethods, UserDataWrapped,
};
use crate::util::{
assert_stack, init_userdata_metatable, push_userdata, take_userdata, StackGuard,
assert_stack, get_userdata, init_userdata_metatable, push_userdata, take_userdata, StackGuard,
};
use crate::value::{FromLua, FromLuaMulti, MultiValue, ToLua, ToLuaMulti, Value};
@ -187,9 +186,12 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
let newtable = self.lua.create_table()?;
let destructor: DestructorCallback = Box::new(move |ud| {
let state = ud.lua.state;
let _sg = StackGuard::new(state);
assert_stack(state, 2);
ud.lua.push_ref(&ud);
// We know the destructor has not run yet because we hold a reference to the userdata.
// Clear uservalue
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
ffi::lua_pushnil(state);
@ -197,8 +199,6 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
ud.lua.push_ref(&newtable.0);
ffi::lua_setuservalue(state, -2);
// We know the destructor has not run yet because we hold a reference to the
// userdata.
vec![Box::new(take_userdata::<UserDataCell<T>>(state))]
});
self.destructors
@ -236,7 +236,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
where
T: 'scope + UserData,
{
let data = Rc::new(RefCell::new(UserDataWrapped::new(data)));
let data = UserDataCell::new(UserDataWrapped::new(data));
// 'callback outliving 'scope is a lie to make the types work out, required due to the
// inability to work with the more correct callback type that is universally quantified over
@ -245,7 +245,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
// parameters.
fn wrap_method<'scope, 'lua, 'callback: 'scope, T: 'scope>(
scope: &Scope<'lua, 'scope>,
data: Rc<UserDataCell<T>>,
data: *mut UserDataCell<T>,
method: NonStaticMethod<'callback, T>,
) -> Result<Function<'lua>> {
// On methods that actually receive the userdata, we fake a type check on the passed in
@ -255,24 +255,17 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
// with a type mismatch, but here without this check would proceed as though you had
// called the method on the original value (since we otherwise completely ignore the
// first argument).
let check_data = data.clone();
let check_data = data;
let check_ud_type = move |lua: &'callback Lua, value| {
if let Some(Value::UserData(ud)) = value {
unsafe {
let _sg = StackGuard::new(lua.state);
assert_stack(lua.state, 3);
lua.push_ref(&ud.0);
if ffi::lua_getmetatable(lua.state, -1) == 0 {
return Err(Error::UserDataTypeMismatch);
}
ffi::safe::lua_pushstring(lua.state, "__mlua_ptr")?;
if ffi::lua_rawget(lua.state, -2) == ffi::LUA_TLIGHTUSERDATA {
let ud_ptr = ffi::lua_touserdata(lua.state, -1);
if ud_ptr == check_data.as_ptr() as *mut c_void {
lua.push_userdata_ref(&ud.0)?;
if get_userdata(lua.state, -1) == check_data {
return Ok(());
}
}
}
};
Err(Error::UserDataTypeMismatch)
};
@ -281,7 +274,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
NonStaticMethod::Method(method) => {
let f = Box::new(move |lua, mut args: MultiValue<'callback>| {
check_ud_type(lua, args.pop_front())?;
let data = data
let data = unsafe { &*data }
.try_borrow()
.map(|cell| Ref::map(cell, AsRef::as_ref))
.map_err(|_| Error::UserDataBorrowError)?;
@ -296,7 +289,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
let mut method = method
.try_borrow_mut()
.map_err(|_| Error::RecursiveMutCallback)?;
let mut data = data
let mut data = unsafe { &mut *data }
.try_borrow_mut()
.map(|cell| RefMut::map(cell, AsMut::as_mut))
.map_err(|_| Error::UserDataBorrowMutError)?;
@ -329,18 +322,15 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
let _sg = StackGuard::new(lua.state);
assert_stack(lua.state, 13);
// We need to wrap dummy userdata because their memory can be accessed by serializer
push_userdata(lua.state, UserDataCell::new(UserDataWrapped::new(())))?;
push_userdata(lua.state, data)?;
let data = get_userdata::<UserDataCell<T>>(lua.state, -1);
// Prepare metatable, add meta methods first and then meta fields
let meta_methods_nrec = ud_methods.meta_methods.len() + ud_fields.meta_fields.len() + 1;
ffi::safe::lua_createtable(lua.state, 0, meta_methods_nrec as c_int)?;
ffi::lua_pushlightuserdata(lua.state, data.as_ptr() as *mut c_void);
ffi::safe::lua_rawsetfield(lua.state, -2, "__mlua_ptr")?;
for (k, m) in ud_methods.meta_methods {
lua.push_value(Value::Function(wrap_method(self, data.clone(), m)?))?;
lua.push_value(Value::Function(wrap_method(self, data, m)?))?;
ffi::safe::lua_rawsetfield(lua.state, -2, k.validate()?.name())?;
}
for (k, f) in ud_fields.meta_fields {
@ -354,7 +344,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
if field_getters_nrec > 0 {
ffi::safe::lua_createtable(lua.state, 0, field_getters_nrec as c_int)?;
for (k, m) in ud_fields.field_getters {
lua.push_value(Value::Function(wrap_method(self, data.clone(), m)?))?;
lua.push_value(Value::Function(wrap_method(self, data, m)?))?;
ffi::safe::lua_rawsetfield(lua.state, -2, &k)?;
}
field_getters_index = Some(ffi::lua_absindex(lua.state, -1));
@ -365,7 +355,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
if field_setters_nrec > 0 {
ffi::safe::lua_createtable(lua.state, 0, field_setters_nrec as c_int)?;
for (k, m) in ud_fields.field_setters {
lua.push_value(Value::Function(wrap_method(self, data.clone(), m)?))?;
lua.push_value(Value::Function(wrap_method(self, data, m)?))?;
ffi::safe::lua_rawsetfield(lua.state, -2, &k)?;
}
field_setters_index = Some(ffi::lua_absindex(lua.state, -1));
@ -377,7 +367,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
// Create table used for methods lookup
ffi::safe::lua_createtable(lua.state, 0, methods_nrec as c_int)?;
for (k, m) in ud_methods.methods {
lua.push_value(Value::Function(wrap_method(self, data.clone(), m)?))?;
lua.push_value(Value::Function(wrap_method(self, data, m)?))?;
ffi::safe::lua_rawsetfield(lua.state, -2, &k)?;
}
methods_index = Some(ffi::lua_absindex(lua.state, -1));
@ -404,11 +394,13 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
#[cfg(any(feature = "lua51", feature = "luajit"))]
let newtable = lua.create_table()?;
let destructor: DestructorCallback = Box::new(move |ud| {
// We know the destructor has not run yet because we hold a reference to the userdata.
let state = ud.lua.state;
let _sg = StackGuard::new(state);
assert_stack(state, 2);
ud.lua.push_ref(&ud);
// We know the destructor has not run yet because we hold a reference to the userdata.
// Deregister metatable
ffi::lua_getmetatable(state, -1);
let mt_id = ffi::lua_topointer(state, -1);
@ -422,7 +414,9 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
ud.lua.push_ref(&newtable.0);
ffi::lua_setuservalue(state, -2);
vec![Box::new(take_userdata::<UserDataCell<()>>(state))]
// We cannot put `T` into the vec because `T` does not implement `Any`
drop(take_userdata::<UserDataCell<T>>(state));
vec![]
});
self.destructors
.borrow_mut()
@ -446,6 +440,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
let destructor: DestructorCallback = Box::new(|f| {
let state = f.lua.state;
let _sg = StackGuard::new(state);
assert_stack(state, 3);
f.lua.push_ref(&f);
@ -461,7 +456,6 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
ffi::lua_pushnil(state);
ffi::lua_setupvalue(state, -2, 3);
ffi::lua_pop(state, 1);
vec![Box::new(ud1), Box::new(ud2)]
});
self.destructors
@ -484,6 +478,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
let poll_str = self.lua.create_string("poll")?;
let destructor: DestructorCallback = Box::new(move |f| {
let state = f.lua.state;
let _sg = StackGuard::new(state);
assert_stack(state, 4);
f.lua.push_ref(&f);

6
tests/scope.rs
View File

@ -302,7 +302,7 @@ fn scope_userdata_drop() -> Result<()> {
fn scope_nonstatic_userdata_drop() -> Result<()> {
let lua = Lua::new();
struct MyUserData<'a>(&'a Cell<i64>);
struct MyUserData<'a>(&'a Cell<i64>, Arc<()>);
impl<'a> UserData for MyUserData<'a> {
fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
@ -320,11 +320,11 @@ fn scope_nonstatic_userdata_drop() -> Result<()> {
let i = Cell::new(1);
let arc = Arc::new(());
lua.scope(|scope| {
let ud = scope.create_nonstatic_userdata(MyUserData(&i))?;
let ud = scope.create_nonstatic_userdata(MyUserData(&i, arc.clone()))?;
ud.set_user_value(MyUserDataArc(arc.clone()))?;
lua.globals().set("ud", ud)?;
lua.load("ud:inc()").exec()?;
assert_eq!(Arc::strong_count(&arc), 2);
assert_eq!(Arc::strong_count(&arc), 3);
Ok(())
})?;