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mlua/src/lua.rs

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Rust
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use std::any::TypeId;
use std::cell::{RefCell, UnsafeCell};
use std::ffi::{CStr, CString};
use std::fmt;
use std::marker::PhantomData;
use std::mem::MaybeUninit;
use std::ops::Deref;
use std::os::raw::{c_char, c_int, c_void};
use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe, Location};
use std::ptr::NonNull;
use std::result::Result as StdResult;
use std::sync::atomic::{AtomicPtr, Ordering};
use std::sync::{Arc, Mutex};
use std::{mem, ptr, str};
use rustc_hash::FxHashMap;
use crate::chunk::{AsChunk, Chunk, ChunkMode};
use crate::error::{Error, Result};
use crate::function::Function;
use crate::hook::Debug;
use crate::memory::{MemoryState, ALLOCATOR};
use crate::scope::Scope;
use crate::stdlib::StdLib;
use crate::string::String;
use crate::table::Table;
use crate::thread::Thread;
use crate::types::{
AppData, AppDataRef, AppDataRefMut, Callback, CallbackUpvalue, DestructedUserdata, Integer,
LightUserData, LuaRef, MaybeSend, Number, RegistryKey,
};
use crate::userdata::{AnyUserData, MetaMethod, UserData, UserDataCell};
use crate::userdata_impl::{UserDataProxy, UserDataRegistrar};
use crate::util::{
self, assert_stack, check_stack, get_destructed_userdata_metatable, get_gc_metatable,
get_gc_userdata, get_main_state, get_userdata, init_error_registry, init_gc_metatable,
init_userdata_metatable, pop_error, push_gc_userdata, push_string, push_table, rawset_field,
safe_pcall, safe_xpcall, short_type_name, StackGuard, WrappedFailure,
};
use crate::value::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, MultiValue, Nil, Value};
#[cfg(not(feature = "lua54"))]
use crate::util::push_userdata;
#[cfg(feature = "lua54")]
use crate::{types::WarnCallback, userdata::USER_VALUE_MAXSLOT, util::push_userdata_uv};
#[cfg(not(feature = "luau"))]
use crate::{hook::HookTriggers, types::HookCallback};
#[cfg(feature = "luau")]
use crate::types::InterruptCallback;
#[cfg(any(feature = "luau", doc))]
use crate::{chunk::Compiler, types::VmState};
#[cfg(feature = "async")]
use {
crate::types::{AsyncCallback, AsyncCallbackUpvalue, AsyncPollUpvalue},
futures_util::future::{self, Future, TryFutureExt},
futures_util::task::{noop_waker_ref, Context, Poll, Waker},
};
#[cfg(feature = "serialize")]
use serde::Serialize;
/// Top level Lua struct which represents an instance of Lua VM.
#[repr(transparent)]
pub struct Lua(Arc<LuaInner>);
/// An inner Lua struct which holds a raw Lua state.
pub struct LuaInner {
// The state is dynamic and depends on context
state: AtomicPtr<ffi::lua_State>,
main_state: *mut ffi::lua_State,
extra: Arc<UnsafeCell<ExtraData>>,
}
// Data associated with the Lua.
pub(crate) struct ExtraData {
// Same layout as `Lua`
inner: MaybeUninit<Arc<LuaInner>>,
registered_userdata: FxHashMap<TypeId, c_int>,
registered_userdata_mt: FxHashMap<*const c_void, Option<TypeId>>,
last_checked_userdata_mt: (*const c_void, Option<TypeId>),
// When Lua instance dropped, setting `None` would prevent collecting `RegistryKey`s
registry_unref_list: Arc<Mutex<Option<Vec<c_int>>>>,
// Container to store arbitrary data (extensions)
app_data: AppData,
safe: bool,
libs: StdLib,
mem_state: Option<NonNull<MemoryState>>,
ref_thread: *mut ffi::lua_State,
ref_stack_size: c_int,
ref_stack_top: c_int,
ref_free: Vec<c_int>,
// Pool of `WrappedFailure` enums in the ref thread (as userdata)
wrapped_failure_pool: Vec<c_int>,
// Pool of `MultiValue` containers
multivalue_pool: Vec<MultiValue<'static>>,
// Pool of `Thread`s (coroutines) for async execution
#[cfg(feature = "async")]
thread_pool: Vec<c_int>,
// Address of `WrappedFailure` metatable
wrapped_failure_mt_ptr: *const c_void,
// Waker for polling futures
#[cfg(feature = "async")]
waker: NonNull<Waker>,
#[cfg(not(feature = "luau"))]
hook_callback: Option<HookCallback>,
#[cfg(not(feature = "luau"))]
hook_thread: *mut ffi::lua_State,
#[cfg(feature = "lua54")]
warn_callback: Option<WarnCallback>,
#[cfg(feature = "luau")]
interrupt_callback: Option<InterruptCallback>,
#[cfg(feature = "luau")]
sandboxed: bool,
#[cfg(feature = "luau")]
compiler: Option<Compiler>,
#[cfg(feature = "luau-jit")]
enable_jit: bool,
}
/// Mode of the Lua garbage collector (GC).
///
/// In Lua 5.4 GC can work in two modes: incremental and generational.
/// Previous Lua versions support only incremental GC.
///
/// More information can be found in the Lua [documentation].
///
/// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum GCMode {
Incremental,
/// Requires `feature = "lua54"`
#[cfg(feature = "lua54")]
#[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
Generational,
}
/// Controls Lua interpreter behavior such as Rust panics handling.
#[derive(Clone, Debug)]
#[non_exhaustive]
pub struct LuaOptions {
/// Catch Rust panics when using [`pcall`]/[`xpcall`].
///
/// If disabled, wraps these functions and automatically resumes panic if found.
/// Also in Lua 5.1 adds ability to provide arguments to [`xpcall`] similar to Lua >= 5.2.
///
/// If enabled, keeps [`pcall`]/[`xpcall`] unmodified.
/// Panics are still automatically resumed if returned to the Rust side.
///
/// Default: **true**
///
/// [`pcall`]: https://www.lua.org/manual/5.4/manual.html#pdf-pcall
/// [`xpcall`]: https://www.lua.org/manual/5.4/manual.html#pdf-xpcall
pub catch_rust_panics: bool,
/// Max size of thread (coroutine) object pool used to execute asynchronous functions.
///
/// It works on Lua 5.4, LuaJIT (vendored) and Luau, where [`lua_resetthread`] function
/// is available and allows to reuse old coroutines after resetting their state.
///
/// Default: **0** (disabled)
///
/// [`lua_resetthread`]: https://www.lua.org/manual/5.4/manual.html#lua_resetthread
#[cfg(feature = "async")]
#[cfg_attr(docsrs, doc(cfg(feature = "async")))]
pub thread_pool_size: usize,
}
impl Default for LuaOptions {
fn default() -> Self {
LuaOptions::new()
}
}
impl LuaOptions {
/// Returns a new instance of `LuaOptions` with default parameters.
pub const fn new() -> Self {
LuaOptions {
catch_rust_panics: true,
#[cfg(feature = "async")]
thread_pool_size: 0,
}
}
/// Sets [`catch_rust_panics`] option.
///
/// [`catch_rust_panics`]: #structfield.catch_rust_panics
#[must_use]
pub const fn catch_rust_panics(mut self, enabled: bool) -> Self {
self.catch_rust_panics = enabled;
self
}
/// Sets [`thread_pool_size`] option.
///
/// [`thread_pool_size`]: #structfield.thread_pool_size
#[cfg(feature = "async")]
#[cfg_attr(docsrs, doc(cfg(feature = "async")))]
#[must_use]
pub const fn thread_pool_size(mut self, size: usize) -> Self {
self.thread_pool_size = size;
self
}
}
#[cfg(feature = "async")]
pub(crate) static ASYNC_POLL_PENDING: u8 = 0;
pub(crate) static EXTRA_REGISTRY_KEY: u8 = 0;
const WRAPPED_FAILURE_POOL_SIZE: usize = 64;
const MULTIVALUE_POOL_SIZE: usize = 64;
/// Requires `feature = "send"`
#[cfg(feature = "send")]
#[cfg_attr(docsrs, doc(cfg(feature = "send")))]
unsafe impl Send for Lua {}
#[cfg(not(feature = "module"))]
impl Drop for Lua {
fn drop(&mut self) {
let _ = self.gc_collect();
}
}
#[cfg(not(feature = "module"))]
impl Drop for LuaInner {
fn drop(&mut self) {
unsafe {
#[cfg(feature = "luau")]
{
(*ffi::lua_callbacks(self.state())).userdata = ptr::null_mut();
}
ffi::lua_close(self.main_state);
}
}
}
impl Drop for ExtraData {
fn drop(&mut self) {
#[cfg(feature = "module")]
unsafe {
self.inner.assume_init_drop();
}
*mlua_expect!(self.registry_unref_list.lock(), "unref list poisoned") = None;
if let Some(mem_state) = self.mem_state {
drop(unsafe { Box::from_raw(mem_state.as_ptr()) });
}
}
}
impl fmt::Debug for Lua {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Lua({:p})", self.state())
}
}
impl Deref for Lua {
type Target = LuaInner;
#[inline]
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl Lua {
/// Creates a new Lua state and loads the **safe** subset of the standard libraries.
///
/// # Safety
/// The created Lua state would have _some_ safety guarantees and would not allow to load unsafe
/// standard libraries or C modules.
///
/// See [`StdLib`] documentation for a list of unsafe modules that cannot be loaded.
///
/// [`StdLib`]: crate::StdLib
#[allow(clippy::new_without_default)]
pub fn new() -> Lua {
mlua_expect!(
Self::new_with(StdLib::ALL_SAFE, LuaOptions::default()),
"Cannot create new safe Lua state"
)
}
/// Creates a new Lua state and loads all the standard libraries.
///
/// # Safety
/// The created Lua state would not have safety guarantees and would allow to load C modules.
pub unsafe fn unsafe_new() -> Lua {
Self::unsafe_new_with(StdLib::ALL, LuaOptions::default())
}
/// Creates a new Lua state and loads the specified safe subset of the standard libraries.
///
/// Use the [`StdLib`] flags to specify the libraries you want to load.
///
/// # Safety
/// The created Lua state would have _some_ safety guarantees and would not allow to load unsafe
/// standard libraries or C modules.
///
/// See [`StdLib`] documentation for a list of unsafe modules that cannot be loaded.
///
/// [`StdLib`]: crate::StdLib
pub fn new_with(libs: StdLib, options: LuaOptions) -> Result<Lua> {
#[cfg(not(feature = "luau"))]
if libs.contains(StdLib::DEBUG) {
return Err(Error::SafetyError(
"The unsafe `debug` module can't be loaded using safe `new_with`".to_string(),
));
}
#[cfg(feature = "luajit")]
if libs.contains(StdLib::FFI) {
return Err(Error::SafetyError(
"The unsafe `ffi` module can't be loaded using safe `new_with`".to_string(),
));
}
let lua = unsafe { Self::inner_new(libs, options) };
#[cfg(not(feature = "luau"))]
if libs.contains(StdLib::PACKAGE) {
mlua_expect!(lua.disable_c_modules(), "Error during disabling C modules");
}
unsafe { (*lua.extra.get()).safe = true };
Ok(lua)
}
/// Creates a new Lua state and loads the specified subset of the standard libraries.
///
/// Use the [`StdLib`] flags to specify the libraries you want to load.
///
/// # Safety
/// The created Lua state will not have safety guarantees and allow to load C modules.
///
/// [`StdLib`]: crate::StdLib
pub unsafe fn unsafe_new_with(libs: StdLib, options: LuaOptions) -> Lua {
#[cfg(not(feature = "luau"))]
{
// Workaround to avoid stripping a few unused Lua symbols that could be imported
// by C modules in unsafe mode
let mut _symbols: Vec<*const extern "C" fn()> = vec![
ffi::lua_atpanic as _,
ffi::lua_isuserdata as _,
ffi::lua_tocfunction as _,
ffi::luaL_loadstring as _,
ffi::luaL_openlibs as _,
];
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
{
_symbols.push(ffi::lua_getglobal as _);
_symbols.push(ffi::lua_setglobal as _);
_symbols.push(ffi::luaL_setfuncs as _);
}
}
Self::inner_new(libs, options)
}
/// Creates a new Lua state with required `libs` and `options`
unsafe fn inner_new(libs: StdLib, options: LuaOptions) -> Lua {
// Skip Rust allocator for non-vendored LuaJIT (see https://github.com/khvzak/mlua/issues/176)
let use_rust_allocator = !(cfg!(feature = "luajit") && cfg!(not(feature = "vendored")));
let (state, mem_state) = if use_rust_allocator {
let mut mem_state: *mut MemoryState = Box::into_raw(Box::default());
let mut state = ffi::lua_newstate(ALLOCATOR, mem_state as *mut c_void);
// If state is null (it's possible for LuaJIT on non-x86 arch) then switch to Lua internal allocator
if state.is_null() {
drop(Box::from_raw(mem_state));
mem_state = ptr::null_mut();
state = ffi::luaL_newstate();
}
(state, mem_state)
} else {
(ffi::luaL_newstate(), ptr::null_mut())
};
assert!(!state.is_null(), "Failed to instantiate Lua VM");
ffi::luaL_requiref(state, cstr!("_G"), ffi::luaopen_base, 1);
ffi::lua_pop(state, 1);
// Init Luau code generator (jit)
#[cfg(feature = "luau-jit")]
if ffi::luau_codegen_supported() != 0 {
ffi::luau_codegen_create(state);
}
let lua = Lua::init_from_ptr(state);
let extra = lua.extra.get();
(*extra).mem_state = NonNull::new(mem_state);
mlua_expect!(
load_from_std_lib(state, libs),
"Error during loading standard libraries"
);
(*extra).libs |= libs;
if !options.catch_rust_panics {
mlua_expect!(
(|| -> Result<()> {
let _sg = StackGuard::new(state);
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_RIDX_GLOBALS);
#[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
ffi::lua_pushvalue(state, ffi::LUA_GLOBALSINDEX);
ffi::lua_pushcfunction(state, safe_pcall);
rawset_field(state, -2, "pcall")?;
ffi::lua_pushcfunction(state, safe_xpcall);
rawset_field(state, -2, "xpcall")?;
Ok(())
})(),
"Error during applying option `catch_rust_panics`"
)
}
#[cfg(feature = "async")]
if options.thread_pool_size > 0 {
(*extra).thread_pool.reserve_exact(options.thread_pool_size);
}
#[cfg(feature = "luau")]
mlua_expect!(lua.prepare_luau_state(), "Error preparing Luau state");
lua
}
/// Constructs a new Lua instance from an existing raw state.
///
/// Once called, a returned Lua state is cached in the registry and can be retrieved
/// by calling this function again.
#[allow(clippy::missing_safety_doc)]
pub unsafe fn init_from_ptr(state: *mut ffi::lua_State) -> Lua {
assert!(!state.is_null(), "Lua state is NULL");
if let Some(lua) = Lua::try_from_ptr(state) {
return lua;
}
let main_state = get_main_state(state).unwrap_or(state);
let main_state_top = ffi::lua_gettop(main_state);
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")]
{
init_gc_metatable::<AsyncCallback>(state, None)?;
init_gc_metatable::<AsyncCallbackUpvalue>(state, None)?;
init_gc_metatable::<AsyncPollUpvalue>(state, None)?;
init_gc_metatable::<Option<Waker>>(state, None)?;
}
// Init serde metatables
#[cfg(feature = "serialize")]
crate::serde::init_metatables(state)?;
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!(main_state, 0, 0, |state| {
let thread = ffi::lua_newthread(state);
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX);
thread
}),
"Error while creating ref thread",
);
let wrapped_failure_mt_ptr = {
get_gc_metatable::<WrappedFailure>(main_state);
let ptr = ffi::lua_topointer(main_state, -1);
ffi::lua_pop(main_state, 1);
ptr
};
// Create ExtraData
let extra = Arc::new(UnsafeCell::new(ExtraData {
inner: MaybeUninit::uninit(),
registered_userdata: FxHashMap::default(),
registered_userdata_mt: FxHashMap::default(),
last_checked_userdata_mt: (ptr::null(), None),
registry_unref_list: Arc::new(Mutex::new(Some(Vec::new()))),
app_data: AppData::default(),
safe: false,
libs: StdLib::NONE,
mem_state: None,
ref_thread,
// We need 1 extra stack space to move values in and out of the ref stack.
ref_stack_size: ffi::LUA_MINSTACK - 1,
ref_stack_top: ffi::lua_gettop(ref_thread),
ref_free: Vec::new(),
wrapped_failure_pool: Vec::with_capacity(WRAPPED_FAILURE_POOL_SIZE),
multivalue_pool: Vec::with_capacity(MULTIVALUE_POOL_SIZE),
#[cfg(feature = "async")]
thread_pool: Vec::new(),
wrapped_failure_mt_ptr,
#[cfg(feature = "async")]
waker: NonNull::from(noop_waker_ref()),
#[cfg(not(feature = "luau"))]
hook_callback: None,
#[cfg(not(feature = "luau"))]
hook_thread: ptr::null_mut(),
#[cfg(feature = "lua54")]
warn_callback: None,
#[cfg(feature = "luau")]
interrupt_callback: None,
#[cfg(feature = "luau")]
sandboxed: false,
#[cfg(feature = "luau")]
compiler: None,
#[cfg(feature = "luau-jit")]
enable_jit: true,
}));
// Store it in the registry
mlua_expect!(
(|state| {
push_gc_userdata(state, Arc::clone(&extra), true)?;
protect_lua!(state, 1, 0, fn(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",
);
// Register `DestructedUserdata` type
get_destructed_userdata_metatable(main_state);
let destructed_mt_ptr = ffi::lua_topointer(main_state, -1);
let destructed_ud_typeid = TypeId::of::<DestructedUserdata>();
(*extra.get())
.registered_userdata_mt
.insert(destructed_mt_ptr, Some(destructed_ud_typeid));
ffi::lua_pop(main_state, 1);
mlua_debug_assert!(
ffi::lua_gettop(main_state) == main_state_top,
"stack leak during creation"
);
assert_stack(main_state, ffi::LUA_MINSTACK);
// Set Luau callbacks userdata to extra data
// We can use global callbacks userdata since we don't allow C modules in Luau
#[cfg(feature = "luau")]
{
(*ffi::lua_callbacks(main_state)).userdata = extra.get() as *mut c_void;
}
let inner = Arc::new(LuaInner {
state: AtomicPtr::new(state),
main_state,
extra: Arc::clone(&extra),
});
(*extra.get()).inner.write(Arc::clone(&inner));
#[cfg(not(feature = "module"))]
Arc::decrement_strong_count(Arc::as_ptr(&inner));
Lua(inner)
}
/// Loads the specified subset of the standard libraries into an existing Lua state.
///
/// Use the [`StdLib`] flags to specify the libraries you want to load.
///
/// [`StdLib`]: crate::StdLib
pub fn load_from_std_lib(&self, libs: StdLib) -> Result<()> {
#[cfg(not(feature = "luau"))]
let is_safe = unsafe { (*self.extra.get()).safe };
#[cfg(not(feature = "luau"))]
if is_safe && libs.contains(StdLib::DEBUG) {
return Err(Error::SafetyError(
"the unsafe `debug` module can't be loaded in safe mode".to_string(),
));
}
#[cfg(feature = "luajit")]
if is_safe && libs.contains(StdLib::FFI) {
return Err(Error::SafetyError(
"the unsafe `ffi` module can't be loaded in safe mode".to_string(),
));
}
let res = unsafe { load_from_std_lib(self.main_state, libs) };
// If `package` library loaded into a safe lua state then disable C modules
#[cfg(not(feature = "luau"))]
{
let curr_libs = unsafe { (*self.extra.get()).libs };
if is_safe && (curr_libs ^ (curr_libs | libs)).contains(StdLib::PACKAGE) {
mlua_expect!(self.disable_c_modules(), "Error during disabling C modules");
}
}
unsafe { (*self.extra.get()).libs |= libs };
res
}
/// Loads module `modname` into an existing Lua state using the specified entrypoint
/// function.
///
/// Internally calls the Lua function `func` with the string `modname` as an argument,
/// sets the call result to `package.loaded[modname]` and returns copy of the result.
///
/// If `package.loaded[modname]` value is not nil, returns copy of the value without
/// calling the function.
///
/// If the function does not return a non-nil value then this method assigns true to
/// `package.loaded[modname]`.
///
/// Behavior is similar to Lua's [`require`] function.
///
/// [`require`]: https://www.lua.org/manual/5.4/manual.html#pdf-require
pub fn load_from_function<'lua, T>(&'lua self, modname: &str, func: Function<'lua>) -> Result<T>
where
T: FromLua<'lua>,
{
let state = self.state();
let loaded = unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 2)?;
protect_lua!(state, 0, 1, fn(state) {
ffi::luaL_getsubtable(state, ffi::LUA_REGISTRYINDEX, cstr!("_LOADED"));
})?;
Table(self.pop_ref())
};
let modname = self.create_string(modname)?;
let value = match loaded.raw_get(modname.clone())? {
Value::Nil => {
let result = match func.call(modname.clone())? {
Value::Nil => Value::Boolean(true),
res => res,
};
loaded.raw_set(modname, result.clone())?;
result
}
res => res,
};
T::from_lua(value, self)
}
/// Unloads module `modname`.
///
/// Removes module from the [`package.loaded`] table which allows to load it again.
/// It does not support unloading binary Lua modules since they are internally cached and can be
/// unloaded only by closing Lua state.
///
/// [`package.loaded`]: https://www.lua.org/manual/5.4/manual.html#pdf-package.loaded
pub fn unload(&self, modname: &str) -> Result<()> {
let state = self.state();
let loaded = unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 2)?;
protect_lua!(state, 0, 1, fn(state) {
ffi::luaL_getsubtable(state, ffi::LUA_REGISTRYINDEX, cstr!("_LOADED"));
})?;
Table(self.pop_ref())
};
let modname = self.create_string(modname)?;
loaded.raw_remove(modname)?;
Ok(())
}
/// Consumes and leaks `Lua` object, returning a static reference `&'static Lua`.
///
/// This function is useful when the `Lua` object is supposed to live for the remainder
/// of the program's life.
/// In particular in asynchronous context this will allow to spawn Lua tasks to execute
/// in background.
///
/// Dropping the returned reference will cause a memory leak. If this is not acceptable,
/// the reference should first be wrapped with the [`Lua::from_static`] function producing a `Lua`.
/// This `Lua` object can then be dropped which will properly release the allocated memory.
///
/// [`Lua::from_static`]: #method.from_static
#[doc(hidden)]
pub fn into_static(self) -> &'static Self {
Box::leak(Box::new(self))
}
/// Constructs a `Lua` from a static reference to it.
///
/// # Safety
/// This function is unsafe because improper use may lead to memory problems or undefined behavior.
#[doc(hidden)]
pub unsafe fn from_static(lua: &'static Lua) -> Self {
*Box::from_raw(lua as *const Lua as *mut Lua)
}
// Executes module entrypoint function, which returns only one Value.
// The returned value then pushed onto the stack.
#[doc(hidden)]
#[cfg(not(tarpaulin_include))]
pub unsafe fn entrypoint<'lua, A, R, F>(self, func: F) -> Result<c_int>
where
A: FromLuaMulti<'lua>,
R: IntoLua<'lua>,
F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>,
{
let entrypoint_inner = |lua: &'lua Lua, func: F| {
let state = lua.state();
let nargs = ffi::lua_gettop(state);
check_stack(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(args, 1, None, lua)?)?.into_lua_multi(lua)
}))?;
callback.call(args)
};
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: IntoLua<'lua>,
F: 'static + MaybeSend + Fn(&'lua Lua) -> Result<R>,
{
self.entrypoint(move |lua, _: ()| func(lua))
}
/// Enables (or disables) sandbox mode on this Lua instance.
///
/// This method, in particular:
/// - Set all libraries to read-only
/// - Set all builtin metatables to read-only
/// - Set globals to read-only (and activates safeenv)
/// - Setup local environment table that performs writes locally and proxies reads
/// to the global environment.
///
/// # Examples
///
/// ```
/// # use mlua::{Lua, Result};
/// # fn main() -> Result<()> {
/// let lua = Lua::new();
///
/// lua.sandbox(true)?;
/// lua.load("var = 123").exec()?;
/// assert_eq!(lua.globals().get::<_, u32>("var")?, 123);
///
/// // Restore the global environment (clear changes made in sandbox)
/// lua.sandbox(false)?;
/// assert_eq!(lua.globals().get::<_, Option<u32>>("var")?, None);
/// # Ok(())
/// # }
/// ```
///
/// Requires `feature = "luau"`
#[cfg(any(feature = "luau", docsrs))]
#[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
pub fn sandbox(&self, enabled: bool) -> Result<()> {
unsafe {
if (*self.extra.get()).sandboxed != enabled {
let state = self.main_state;
check_stack(state, 3)?;
protect_lua!(state, 0, 0, |state| {
if enabled {
ffi::luaL_sandbox(state, 1);
ffi::luaL_sandboxthread(state);
} else {
// Restore original `LUA_GLOBALSINDEX`
ffi::lua_xpush(self.ref_thread(), state, ffi::LUA_GLOBALSINDEX);
ffi::lua_replace(state, ffi::LUA_GLOBALSINDEX);
ffi::luaL_sandbox(state, 0);
}
})?;
(*self.extra.get()).sandboxed = enabled;
}
Ok(())
}
}
/// Sets a 'hook' function that will periodically be called as Lua code executes.
///
/// When exactly the hook function is called depends on the contents of the `triggers`
/// parameter, see [`HookTriggers`] for more details.
///
/// The provided hook function can error, and this error will be propagated through the Lua code
/// that was executing at the time the hook was triggered. This can be used to implement a
/// limited form of execution limits by setting [`HookTriggers.every_nth_instruction`] and
/// erroring once an instruction limit has been reached.
///
/// This method sets a hook function for the main thread (if available) of this Lua instance.
/// If you want to set a hook function for a thread (coroutine), use [`Thread::set_hook()`] instead.
///
/// Please note you cannot have more than one hook function set at a time for this Lua instance.
///
/// # Example
///
/// Shows each line number of code being executed by the Lua interpreter.
///
/// ```
/// # use mlua::{Lua, HookTriggers, Result};
/// # fn main() -> Result<()> {
/// let lua = Lua::new();
/// lua.set_hook(HookTriggers::EVERY_LINE, |_lua, debug| {
/// println!("line {}", debug.curr_line());
/// Ok(())
/// })?;
///
/// lua.load(r#"
/// local x = 2 + 3
/// local y = x * 63
/// local z = string.len(x..", "..y)
/// "#).exec()
/// # }
/// ```
///
/// [`HookTriggers`]: crate::HookTriggers
/// [`HookTriggers.every_nth_instruction`]: crate::HookTriggers::every_nth_instruction
#[cfg(not(feature = "luau"))]
#[cfg_attr(docsrs, doc(cfg(not(feature = "luau"))))]
pub fn set_hook<F>(&self, triggers: HookTriggers, callback: F) -> Result<()>
where
F: Fn(&Lua, Debug) -> Result<()> + MaybeSend + 'static,
{
unsafe {
let state = get_main_state(self.main_state).ok_or(Error::MainThreadNotAvailable)?;
self.set_thread_hook(state, triggers, callback);
}
Ok(())
}
/// Sets a 'hook' function for a thread (coroutine).
#[cfg(not(feature = "luau"))]
pub(crate) unsafe fn set_thread_hook<F>(
&self,
state: *mut ffi::lua_State,
triggers: HookTriggers,
callback: F,
) where
F: Fn(&Lua, Debug) -> Result<()> + MaybeSend + 'static,
{
unsafe extern "C" fn hook_proc(state: *mut ffi::lua_State, ar: *mut ffi::lua_Debug) {
let extra = extra_data(state);
if (*extra).hook_thread != state {
// Hook was destined for a different thread, ignore
ffi::lua_sethook(state, None, 0, 0);
return;
}
callback_error_ext(state, extra, move |_| {
let hook_cb = (*extra).hook_callback.clone();
let hook_cb = mlua_expect!(hook_cb, "no hook callback set in hook_proc");
if Arc::strong_count(&hook_cb) > 2 {
return Ok(()); // Don't allow recursion
}
let lua: &Lua = mem::transmute((*extra).inner.assume_init_ref());
let _guard = StateGuard::new(&lua.0, state);
let debug = Debug::new(lua, ar);
hook_cb(lua, debug)
})
}
(*self.extra.get()).hook_callback = Some(Arc::new(callback));
(*self.extra.get()).hook_thread = state; // Mark for what thread the hook is set
ffi::lua_sethook(state, Some(hook_proc), triggers.mask(), triggers.count());
}
/// Removes any hook previously set by [`Lua::set_hook()`] or [`Thread::set_hook()`].
///
/// This function has no effect if a hook was not previously set.
#[cfg(not(feature = "luau"))]
#[cfg_attr(docsrs, doc(cfg(not(feature = "luau"))))]
pub fn remove_hook(&self) {
unsafe {
let state = self.state();
ffi::lua_sethook(state, None, 0, 0);
match get_main_state(self.main_state) {
Some(main_state) if !ptr::eq(state, main_state) => {
// If main_state is different from state, remove hook from it too
ffi::lua_sethook(main_state, None, 0, 0);
}
_ => {}
};
(*self.extra.get()).hook_callback = None;
(*self.extra.get()).hook_thread = ptr::null_mut();
}
}
/// Sets an 'interrupt' function that will periodically be called by Luau VM.
///
/// Any Luau code is guaranteed to call this handler "eventually"
/// (in practice this can happen at any function call or at any loop iteration).
///
/// The provided interrupt function can error, and this error will be propagated through
/// the Luau code that was executing at the time the interrupt was triggered.
/// Also this can be used to implement continuous execution limits by instructing Luau VM to yield
/// by returning [`VmState::Yield`].
///
/// This is similar to [`Lua::set_hook`] but in more simplified form.
///
/// # Example
///
/// Periodically yield Luau VM to suspend execution.
///
/// ```
/// # use std::sync::{Arc, atomic::{AtomicU64, Ordering}};
/// # use mlua::{Lua, Result, ThreadStatus, VmState};
/// # fn main() -> Result<()> {
/// let lua = Lua::new();
/// let count = Arc::new(AtomicU64::new(0));
/// lua.set_interrupt(move |_| {
/// if count.fetch_add(1, Ordering::Relaxed) % 2 == 0 {
/// return Ok(VmState::Yield);
/// }
/// Ok(VmState::Continue)
/// });
///
/// let co = lua.create_thread(
/// lua.load(r#"
/// local b = 0
/// for _, x in ipairs({1, 2, 3}) do b += x end
/// "#)
/// .into_function()?,
/// )?;
/// while co.status() == ThreadStatus::Resumable {
/// co.resume(())?;
/// }
/// # Ok(())
/// # }
/// ```
#[cfg(any(feature = "luau", docsrs))]
#[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
pub fn set_interrupt<F>(&self, callback: F)
where
F: Fn(&Lua) -> Result<VmState> + MaybeSend + 'static,
{
unsafe extern "C" fn interrupt_proc(state: *mut ffi::lua_State, gc: c_int) {
if gc >= 0 {
// We don't support GC interrupts since they cannot survive Lua exceptions
return;
}
let extra = extra_data(state);
let result = callback_error_ext(state, extra, move |_| {
let interrupt_cb = (*extra).interrupt_callback.clone();
let interrupt_cb =
mlua_expect!(interrupt_cb, "no interrupt callback set in interrupt_proc");
if Arc::strong_count(&interrupt_cb) > 2 {
return Ok(VmState::Continue); // Don't allow recursion
}
let lua: &Lua = mem::transmute((*extra).inner.assume_init_ref());
let _guard = StateGuard::new(&lua.0, state);
interrupt_cb(lua)
});
match result {
VmState::Continue => {}
VmState::Yield => {
ffi::lua_yield(state, 0);
}
}
}
unsafe {
(*self.extra.get()).interrupt_callback = Some(Arc::new(callback));
(*ffi::lua_callbacks(self.main_state)).interrupt = Some(interrupt_proc);
}
}
/// Removes any 'interrupt' previously set by `set_interrupt`.
///
/// This function has no effect if an 'interrupt' was not previously set.
#[cfg(any(feature = "luau", docsrs))]
#[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
pub fn remove_interrupt(&self) {
unsafe {
(*self.extra.get()).interrupt_callback = None;
(*ffi::lua_callbacks(self.main_state)).interrupt = None;
}
}
/// Sets the warning function to be used by Lua to emit warnings.
///
/// Requires `feature = "lua54"`
#[cfg(feature = "lua54")]
#[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
pub fn set_warning_function<F>(&self, callback: F)
where
F: 'static + MaybeSend + Fn(&Lua, &CStr, bool) -> Result<()>,
{
unsafe extern "C" fn warn_proc(ud: *mut c_void, msg: *const c_char, tocont: c_int) {
let extra = ud as *mut ExtraData;
let lua: &Lua = mem::transmute((*extra).inner.assume_init_ref());
callback_error_ext(lua.state(), extra, |_| {
let cb = mlua_expect!(
(*extra).warn_callback.as_ref(),
"no warning callback set in warn_proc"
);
let msg = CStr::from_ptr(msg);
cb(lua, msg, tocont != 0)
});
}
let state = self.main_state;
unsafe {
(*self.extra.get()).warn_callback = Some(Box::new(callback));
ffi::lua_setwarnf(state, Some(warn_proc), self.extra.get() as *mut c_void);
}
}
/// Removes warning function previously set by `set_warning_function`.
///
/// This function has no effect if a warning function was not previously set.
///
/// Requires `feature = "lua54"`
#[cfg(feature = "lua54")]
#[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
pub fn remove_warning_function(&self) {
unsafe {
(*self.extra.get()).warn_callback = None;
ffi::lua_setwarnf(self.main_state, None, ptr::null_mut());
}
}
/// Emits a warning with the given message.
///
/// A message in a call with `tocont` set to `true` should be continued in another call to this function.
///
/// Requires `feature = "lua54"`
#[cfg(feature = "lua54")]
#[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
pub fn warning<S: Into<Vec<u8>>>(&self, msg: S, tocont: bool) -> Result<()> {
let msg = CString::new(msg).map_err(|err| Error::RuntimeError(err.to_string()))?;
unsafe { ffi::lua_warning(self.state(), msg.as_ptr(), tocont as c_int) };
Ok(())
}
/// Gets information about the interpreter runtime stack.
///
/// This function returns [`Debug`] structure that can be used to get information about the function
/// executing at a given level. Level `0` is the current running function, whereas level `n+1` is the
/// function that has called level `n` (except for tail calls, which do not count in the stack).
///
/// [`Debug`]: crate::hook::Debug
pub fn inspect_stack(&self, level: usize) -> Option<Debug> {
unsafe {
let mut ar: ffi::lua_Debug = mem::zeroed();
let level = level as c_int;
#[cfg(not(feature = "luau"))]
if ffi::lua_getstack(self.state(), level, &mut ar) == 0 {
return None;
}
#[cfg(feature = "luau")]
if ffi::lua_getinfo(self.state(), level, cstr!(""), &mut ar) == 0 {
return None;
}
Some(Debug::new_owned(self, level, ar))
}
}
/// Returns the amount of memory (in bytes) currently used inside this Lua state.
pub fn used_memory(&self) -> usize {
unsafe {
match (*self.extra.get()).mem_state.map(|x| x.as_ref()) {
Some(mem_state) => mem_state.used_memory(),
None => {
// Get data from the Lua GC
let used_kbytes = ffi::lua_gc(self.main_state, ffi::LUA_GCCOUNT, 0);
let used_kbytes_rem = ffi::lua_gc(self.main_state, ffi::LUA_GCCOUNTB, 0);
(used_kbytes as usize) * 1024 + (used_kbytes_rem as usize)
}
}
}
}
/// Sets a memory limit (in bytes) on this Lua state.
///
/// Once an allocation occurs that would pass this memory limit,
/// a `Error::MemoryError` is generated instead.
/// Returns previous limit (zero means no limit).
///
/// Does not work on module mode where Lua state is managed externally.
pub fn set_memory_limit(&self, limit: usize) -> Result<usize> {
unsafe {
match (*self.extra.get()).mem_state.map(|mut x| x.as_mut()) {
Some(mem_state) => Ok(mem_state.set_memory_limit(limit)),
None => Err(Error::MemoryLimitNotAvailable),
}
}
}
/// Returns true if the garbage collector is currently running automatically.
///
/// Requires `feature = "lua54/lua53/lua52/luau"`
#[cfg(any(
feature = "lua54",
feature = "lua53",
feature = "lua52",
feature = "luau"
))]
pub fn gc_is_running(&self) -> bool {
unsafe { ffi::lua_gc(self.main_state, ffi::LUA_GCISRUNNING, 0) != 0 }
}
/// Stop the Lua GC from running
pub fn gc_stop(&self) {
unsafe { ffi::lua_gc(self.main_state, ffi::LUA_GCSTOP, 0) };
}
/// Restarts the Lua GC if it is not running
pub fn gc_restart(&self) {
unsafe { ffi::lua_gc(self.main_state, ffi::LUA_GCRESTART, 0) };
}
/// Perform a full garbage-collection cycle.
///
/// It may be necessary to call this function twice to collect all currently unreachable
/// objects. Once to finish the current gc cycle, and once to start and finish the next cycle.
pub fn gc_collect(&self) -> Result<()> {
unsafe {
check_stack(self.main_state, 2)?;
protect_lua!(self.main_state, 0, 0, fn(state) ffi::lua_gc(state, ffi::LUA_GCCOLLECT, 0))
}
}
/// Steps the garbage collector one indivisible step.
///
/// Returns true if this has finished a collection cycle.
pub fn gc_step(&self) -> Result<bool> {
self.gc_step_kbytes(0)
}
/// Steps the garbage collector as though memory had been allocated.
///
/// if `kbytes` is 0, then this is the same as calling `gc_step`. Returns true if this step has
/// finished a collection cycle.
pub fn gc_step_kbytes(&self, kbytes: c_int) -> Result<bool> {
unsafe {
check_stack(self.main_state, 3)?;
protect_lua!(self.main_state, 0, 0, |state| {
ffi::lua_gc(state, ffi::LUA_GCSTEP, kbytes) != 0
})
}
}
/// Sets the 'pause' value of the collector.
///
/// Returns the previous value of 'pause'. More information can be found in the Lua
/// [documentation].
///
/// For Luau this parameter sets GC goal
///
/// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5
pub fn gc_set_pause(&self, pause: c_int) -> c_int {
unsafe {
#[cfg(not(feature = "luau"))]
return ffi::lua_gc(self.main_state, ffi::LUA_GCSETPAUSE, pause);
#[cfg(feature = "luau")]
return ffi::lua_gc(self.main_state, ffi::LUA_GCSETGOAL, pause);
}
}
/// Sets the 'step multiplier' value of the collector.
///
/// Returns the previous value of the 'step multiplier'. More information can be found in the
/// Lua [documentation].
///
/// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5
pub fn gc_set_step_multiplier(&self, step_multiplier: c_int) -> c_int {
unsafe { ffi::lua_gc(self.main_state, ffi::LUA_GCSETSTEPMUL, step_multiplier) }
}
/// Changes the collector to incremental mode with the given parameters.
///
/// Returns the previous mode (always `GCMode::Incremental` in Lua < 5.4).
/// More information can be found in the Lua [documentation].
///
/// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5.1
pub fn gc_inc(&self, pause: c_int, step_multiplier: c_int, step_size: c_int) -> GCMode {
let state = self.main_state;
#[cfg(any(
feature = "lua53",
feature = "lua52",
feature = "lua51",
feature = "luajit",
feature = "luau"
))]
unsafe {
if pause > 0 {
#[cfg(not(feature = "luau"))]
ffi::lua_gc(state, ffi::LUA_GCSETPAUSE, pause);
#[cfg(feature = "luau")]
ffi::lua_gc(state, ffi::LUA_GCSETGOAL, pause);
}
if step_multiplier > 0 {
ffi::lua_gc(state, ffi::LUA_GCSETSTEPMUL, step_multiplier);
}
#[cfg(feature = "luau")]
if step_size > 0 {
ffi::lua_gc(state, ffi::LUA_GCSETSTEPSIZE, step_size);
}
#[cfg(not(feature = "luau"))]
let _ = step_size; // Ignored
GCMode::Incremental
}
#[cfg(feature = "lua54")]
let prev_mode =
unsafe { ffi::lua_gc(state, ffi::LUA_GCINC, pause, step_multiplier, step_size) };
#[cfg(feature = "lua54")]
match prev_mode {
ffi::LUA_GCINC => GCMode::Incremental,
ffi::LUA_GCGEN => GCMode::Generational,
_ => unreachable!(),
}
}
/// Changes the collector to generational mode with the given parameters.
///
/// Returns the previous mode. More information about the generational GC
/// can be found in the Lua 5.4 [documentation][lua_doc].
///
/// Requires `feature = "lua54"`
///
/// [lua_doc]: https://www.lua.org/manual/5.4/manual.html#2.5.2
#[cfg(feature = "lua54")]
#[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
pub fn gc_gen(&self, minor_multiplier: c_int, major_multiplier: c_int) -> GCMode {
let state = self.main_state;
let prev_mode =
unsafe { ffi::lua_gc(state, ffi::LUA_GCGEN, minor_multiplier, major_multiplier) };
match prev_mode {
ffi::LUA_GCGEN => GCMode::Generational,
ffi::LUA_GCINC => GCMode::Incremental,
_ => unreachable!(),
}
}
/// Sets a default Luau compiler (with custom options).
///
/// This compiler will be used by default to load all Lua chunks
/// including via `require` function.
///
/// See [`Compiler`] for details and possible options.
///
/// Requires `feature = "luau"`
#[cfg(any(feature = "luau", doc))]
#[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
pub fn set_compiler(&self, compiler: Compiler) {
unsafe { (*self.extra.get()).compiler = Some(compiler) };
}
/// Toggles JIT compilation mode for new chunks of code.
///
/// By default JIT is enabled. Changing this option does not have any effect on
/// already loaded functions.
#[cfg(any(feature = "luau-jit", docsrs))]
#[cfg_attr(docsrs, doc(cfg(feature = "luau-jit")))]
pub fn enable_jit(&self, enable: bool) {
unsafe { (*self.extra.get()).enable_jit = enable };
}
/// Returns Lua source code as a `Chunk` builder type.
///
/// In order to actually compile or run the resulting code, you must call [`Chunk::exec`] or
/// similar on the returned builder. Code is not even parsed until one of these methods is
/// called.
///
/// [`Chunk::exec`]: crate::Chunk::exec
#[track_caller]
pub fn load<'lua, 'a>(&'lua self, chunk: impl AsChunk<'a>) -> Chunk<'lua, 'a> {
let caller = Location::caller();
Chunk {
lua: self,
name: chunk.name().unwrap_or_else(|| caller.to_string()),
env: chunk.environment(self),
mode: chunk.mode(),
source: chunk.source(),
#[cfg(feature = "luau")]
compiler: unsafe { (*self.extra.get()).compiler.clone() },
}
}
pub(crate) fn load_chunk<'lua>(
&'lua self,
name: Option<&CStr>,
env: Option<Table>,
mode: Option<ChunkMode>,
source: &[u8],
) -> Result<Function<'lua>> {
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 1)?;
let mode_str = match mode {
Some(ChunkMode::Binary) => cstr!("b"),
Some(ChunkMode::Text) => cstr!("t"),
None => cstr!("bt"),
};
match ffi::luaL_loadbufferx(
state,
source.as_ptr() as *const c_char,
source.len(),
name.map(|n| n.as_ptr()).unwrap_or_else(ptr::null),
mode_str,
) {
ffi::LUA_OK => {
if let Some(env) = env {
self.push_ref(&env.0);
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
ffi::lua_setupvalue(state, -2, 1);
#[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
ffi::lua_setfenv(state, -2);
}
#[cfg(feature = "luau-jit")]
if (*self.extra.get()).enable_jit && ffi::luau_codegen_supported() != 0 {
ffi::luau_codegen_compile(state, -1);
}
Ok(Function(self.pop_ref()))
}
err => Err(pop_error(state, err)),
}
}
}
/// Create and return an interned Lua string. Lua strings can be arbitrary [u8] data including
/// embedded nulls, so in addition to `&str` and `&String`, you can also pass plain `&[u8]`
/// here.
pub fn create_string(&self, s: impl AsRef<[u8]>) -> Result<String> {
let state = self.state();
unsafe {
if self.unlikely_memory_error() {
push_string(self.ref_thread(), s.as_ref(), false)?;
return Ok(String(self.pop_ref_thread()));
}
let _sg = StackGuard::new(state);
check_stack(state, 3)?;
push_string(state, s.as_ref(), true)?;
Ok(String(self.pop_ref()))
}
}
/// Creates and returns a new empty table.
pub fn create_table(&self) -> Result<Table> {
self.create_table_with_capacity(0, 0)
}
/// Creates and returns a new empty table, with the specified capacity.
/// `narr` is a hint for how many elements the table will have as a sequence;
/// `nrec` is a hint for how many other elements the table will have.
/// Lua may use these hints to preallocate memory for the new table.
pub fn create_table_with_capacity(&self, narr: c_int, nrec: c_int) -> Result<Table> {
let state = self.state();
unsafe {
if self.unlikely_memory_error() {
push_table(self.ref_thread(), narr, nrec, false)?;
return Ok(Table(self.pop_ref_thread()));
}
let _sg = StackGuard::new(state);
check_stack(state, 3)?;
push_table(state, narr, nrec, true)?;
Ok(Table(self.pop_ref()))
}
}
/// Creates a table and fills it with values from an iterator.
pub fn create_table_from<'lua, K, V, I>(&'lua self, iter: I) -> Result<Table<'lua>>
where
K: IntoLua<'lua>,
V: IntoLua<'lua>,
I: IntoIterator<Item = (K, V)>,
{
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 6)?;
let iter = iter.into_iter();
let lower_bound = iter.size_hint().0;
let protect = !self.unlikely_memory_error();
push_table(state, 0, lower_bound as c_int, protect)?;
for (k, v) in iter {
self.push_value(k.into_lua(self)?)?;
self.push_value(v.into_lua(self)?)?;
if protect {
protect_lua!(state, 3, 1, fn(state) ffi::lua_rawset(state, -3))?;
} else {
ffi::lua_rawset(state, -3);
}
}
Ok(Table(self.pop_ref()))
}
}
/// Creates a table from an iterator of values, using `1..` as the keys.
pub fn create_sequence_from<'lua, T, I>(&'lua self, iter: I) -> Result<Table<'lua>>
where
T: IntoLua<'lua>,
I: IntoIterator<Item = T>,
{
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 5)?;
let iter = iter.into_iter();
let lower_bound = iter.size_hint().0;
let protect = !self.unlikely_memory_error();
push_table(state, lower_bound as c_int, 0, protect)?;
for (i, v) in iter.enumerate() {
self.push_value(v.into_lua(self)?)?;
if protect {
protect_lua!(state, 2, 1, |state| {
ffi::lua_rawseti(state, -2, (i + 1) as Integer);
})?;
} else {
ffi::lua_rawseti(state, -2, (i + 1) as Integer);
}
}
Ok(Table(self.pop_ref()))
}
}
/// Wraps a Rust function or closure, creating a callable Lua function handle to it.
///
/// The function's return value is always a `Result`: If the function returns `Err`, the error
/// is raised as a Lua error, which can be caught using `(x)pcall` or bubble up to the Rust code
/// that invoked the Lua code. This allows using the `?` operator to propagate errors through
/// intermediate Lua code.
///
/// If the function returns `Ok`, the contained value will be converted to one or more Lua
/// values. For details on Rust-to-Lua conversions, refer to the [`IntoLua`] and [`IntoLuaMulti`]
/// traits.
///
/// # Examples
///
/// Create a function which prints its argument:
///
/// ```
/// # use mlua::{Lua, Result};
/// # fn main() -> Result<()> {
/// # let lua = Lua::new();
/// let greet = lua.create_function(|_, name: String| {
/// println!("Hello, {}!", name);
/// Ok(())
/// });
/// # let _ = greet; // used
/// # Ok(())
/// # }
/// ```
///
/// Use tuples to accept multiple arguments:
///
/// ```
/// # use mlua::{Lua, Result};
/// # fn main() -> Result<()> {
/// # let lua = Lua::new();
/// let print_person = lua.create_function(|_, (name, age): (String, u8)| {
/// println!("{} is {} years old!", name, age);
/// Ok(())
/// });
/// # let _ = print_person; // used
/// # Ok(())
/// # }
/// ```
///
/// [`IntoLua`]: crate::IntoLua
/// [`IntoLuaMulti`]: crate::IntoLuaMulti
pub fn create_function<'lua, A, R, F>(&'lua self, func: F) -> Result<Function<'lua>>
where
A: FromLuaMulti<'lua>,
R: IntoLuaMulti<'lua>,
F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>,
{
self.create_callback(Box::new(move |lua, args| {
func(lua, A::from_lua_multi_args(args, 1, None, lua)?)?.into_lua_multi(lua)
}))
}
/// Wraps a Rust mutable closure, creating a callable Lua function handle to it.
///
/// This is a version of [`create_function`] that accepts a FnMut argument. Refer to
/// [`create_function`] for more information about the implementation.
///
/// [`create_function`]: #method.create_function
pub fn create_function_mut<'lua, A, R, F>(&'lua self, func: F) -> Result<Function<'lua>>
where
A: FromLuaMulti<'lua>,
R: IntoLuaMulti<'lua>,
F: 'static + MaybeSend + FnMut(&'lua Lua, A) -> Result<R>,
{
let func = RefCell::new(func);
self.create_function(move |lua, args| {
(*func
.try_borrow_mut()
.map_err(|_| Error::RecursiveMutCallback)?)(lua, args)
})
}
/// Wraps a C function, creating a callable Lua function handle to it.
///
/// # Safety
/// This function is unsafe because provides a way to execute unsafe C function.
pub unsafe fn create_c_function(&self, func: ffi::lua_CFunction) -> Result<Function> {
let state = self.state();
check_stack(state, 1)?;
ffi::lua_pushcfunction(state, func);
Ok(Function(self.pop_ref()))
}
/// Wraps a Rust async function or closure, creating a callable Lua function handle to it.
///
/// While executing the function Rust will poll Future and if the result is not ready, call
/// `yield()` passing internal representation of a `Poll::Pending` value.
///
/// The function must be called inside Lua coroutine ([`Thread`]) to be able to suspend its execution.
/// An executor should be used to poll [`AsyncThread`] and mlua will take a provided Waker
/// in that case. Otherwise noop waker will be used if try to call the function outside of Rust
/// executors.
///
/// The family of `call_async()` functions takes care about creating [`Thread`].
///
/// Requires `feature = "async"`
///
/// # Examples
///
/// Non blocking sleep:
///
/// ```
/// use std::time::Duration;
/// use futures_timer::Delay;
/// use mlua::{Lua, Result};
///
/// async fn sleep(_lua: &Lua, n: u64) -> Result<&'static str> {
/// Delay::new(Duration::from_millis(n)).await;
/// Ok("done")
/// }
///
/// #[tokio::main]
/// async fn main() -> Result<()> {
/// let lua = Lua::new();
/// lua.globals().set("sleep", lua.create_async_function(sleep)?)?;
/// let res: String = lua.load("return sleep(...)").call_async(100).await?; // Sleep 100ms
/// assert_eq!(res, "done");
/// Ok(())
/// }
/// ```
///
/// [`Thread`]: crate::Thread
/// [`AsyncThread`]: crate::AsyncThread
#[cfg(feature = "async")]
#[cfg_attr(docsrs, doc(cfg(feature = "async")))]
pub fn create_async_function<'lua, A, R, F, FR>(&'lua self, func: F) -> Result<Function<'lua>>
where
A: FromLuaMulti<'lua>,
R: IntoLuaMulti<'lua>,
F: 'static + MaybeSend + Fn(&'lua Lua, A) -> FR,
FR: 'lua + Future<Output = Result<R>>,
{
self.create_async_callback(Box::new(move |lua, args| {
let args = match A::from_lua_multi_args(args, 1, None, lua) {
Ok(args) => args,
Err(e) => return Box::pin(future::err(e)),
};
Box::pin(func(lua, args).and_then(move |ret| future::ready(ret.into_lua_multi(lua))))
}))
}
/// Wraps a Lua function into a new thread (or coroutine).
///
/// Equivalent to `coroutine.create`.
pub fn create_thread<'lua>(&'lua self, func: Function) -> Result<Thread<'lua>> {
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 3)?;
let thread_state = if self.unlikely_memory_error() {
ffi::lua_newthread(state)
} else {
protect_lua!(state, 0, 1, |state| ffi::lua_newthread(state))?
};
self.push_ref(&func.0);
ffi::lua_xmove(state, thread_state, 1);
Ok(Thread(self.pop_ref()))
}
}
/// Wraps a Lua function into a new or recycled thread (coroutine).
#[cfg(feature = "async")]
pub(crate) fn create_recycled_thread<'lua>(
&'lua self,
func: &Function,
) -> Result<Thread<'lua>> {
#[cfg(any(
feature = "lua54",
all(feature = "luajit", feature = "vendored"),
feature = "luau",
))]
unsafe {
let state = self.state();
let _sg = StackGuard::new(state);
check_stack(state, 1)?;
if let Some(index) = (*self.extra.get()).thread_pool.pop() {
let thread_state = ffi::lua_tothread(self.ref_thread(), index);
self.push_ref(&func.0);
ffi::lua_xmove(state, thread_state, 1);
#[cfg(feature = "luau")]
{
// Inherit `LUA_GLOBALSINDEX` from the caller
ffi::lua_xpush(state, thread_state, ffi::LUA_GLOBALSINDEX);
ffi::lua_replace(thread_state, ffi::LUA_GLOBALSINDEX);
}
return Ok(Thread(LuaRef::new(self, index)));
}
};
self.create_thread(func.clone())
}
/// Resets thread (coroutine) and returns to the pool for later use.
#[cfg(feature = "async")]
#[cfg(any(
feature = "lua54",
all(feature = "luajit", feature = "vendored"),
feature = "luau",
))]
pub(crate) unsafe fn recycle_thread(&self, thread: &mut Thread) -> bool {
let extra = &mut *self.extra.get();
if extra.thread_pool.len() < extra.thread_pool.capacity() {
let thread_state = ffi::lua_tothread(extra.ref_thread, thread.0.index);
#[cfg(all(feature = "lua54", not(feature = "vendored")))]
let status = ffi::lua_resetthread(thread_state);
#[cfg(all(feature = "lua54", feature = "vendored"))]
let status = ffi::lua_closethread(thread_state, self.state());
#[cfg(feature = "lua54")]
if status != ffi::LUA_OK {
// Error object is on top, drop it
ffi::lua_settop(thread_state, 0);
}
#[cfg(all(feature = "luajit", feature = "vendored"))]
ffi::lua_resetthread(self.state(), thread_state);
#[cfg(feature = "luau")]
ffi::lua_resetthread(thread_state);
extra.thread_pool.push(thread.0.index);
thread.0.drop = false;
return true;
}
false
}
/// Creates a Lua userdata object from a custom userdata type.
///
/// All userdata instances of the same type `T` shares the same metatable.
#[inline]
pub fn create_userdata<T>(&self, data: T) -> Result<AnyUserData>
where
T: UserData + MaybeSend + 'static,
{
unsafe { self.make_userdata(UserDataCell::new(data)) }
}
/// Creates a Lua userdata object from a custom serializable userdata type.
///
/// Requires `feature = "serialize"`
#[cfg(feature = "serialize")]
#[cfg_attr(docsrs, doc(cfg(feature = "serialize")))]
#[inline]
pub fn create_ser_userdata<T>(&self, data: T) -> Result<AnyUserData>
where
T: UserData + Serialize + MaybeSend + 'static,
{
unsafe { self.make_userdata(UserDataCell::new_ser(data)) }
}
/// Creates a Lua userdata object from a custom Rust type.
///
/// You can register the type using [`Lua::register_userdata_type()`] to add fields or methods
/// _before_ calling this method.
/// Otherwise, the userdata object will have an empty metatable.
///
/// All userdata instances of the same type `T` shares the same metatable.
#[inline]
pub fn create_any_userdata<T>(&self, data: T) -> Result<AnyUserData>
where
T: MaybeSend + 'static,
{
unsafe { self.make_any_userdata(UserDataCell::new(data)) }
}
/// Registers a custom Rust type in Lua to use in userdata objects.
///
/// This methods provides a way to add fields or methods to userdata objects of a type `T`.
pub fn register_userdata_type<T: 'static>(
&self,
f: impl FnOnce(&mut UserDataRegistrar<T>),
) -> Result<()> {
let mut registry = UserDataRegistrar::new();
f(&mut registry);
unsafe {
// Deregister the type if it already registered
let type_id = TypeId::of::<T>();
if let Some(&table_id) = (*self.extra.get()).registered_userdata.get(&type_id) {
ffi::luaL_unref(self.state(), ffi::LUA_REGISTRYINDEX, table_id);
}
// Register the type
self.register_userdata_metatable(registry)?;
Ok(())
}
}
/// Create a Lua userdata "proxy" object from a custom userdata type.
///
/// Proxy object is an empty userdata object that has `T` metatable attached.
/// The main purpose of this object is to provide access to static fields and functions
/// without creating an instance of type `T`.
///
/// You can get or set uservalues on this object but you cannot borrow any Rust type.
///
/// # Examples
///
/// ```
/// # use mlua::{Lua, Result, UserData, UserDataFields, UserDataMethods};
/// # fn main() -> Result<()> {
/// # let lua = Lua::new();
/// struct MyUserData(i32);
///
/// impl UserData for MyUserData {
/// fn add_fields<'lua, F: UserDataFields<'lua, Self>>(fields: &mut F) {
/// fields.add_field_method_get("val", |_, this| Ok(this.0));
/// }
///
/// fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
/// methods.add_function("new", |_, value: i32| Ok(MyUserData(value)));
/// }
/// }
///
/// lua.globals().set("MyUserData", lua.create_proxy::<MyUserData>()?)?;
///
/// lua.load("assert(MyUserData.new(321).val == 321)").exec()?;
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn create_proxy<T>(&self) -> Result<AnyUserData>
where
T: 'static + UserData,
{
unsafe { self.make_userdata(UserDataCell::new(UserDataProxy::<T>(PhantomData))) }
}
/// Returns a handle to the global environment.
pub fn globals(&self) -> Table {
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
assert_stack(state, 1);
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_RIDX_GLOBALS);
#[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
ffi::lua_pushvalue(state, ffi::LUA_GLOBALSINDEX);
Table(self.pop_ref())
}
}
/// Returns a handle to the active `Thread`. For calls to `Lua` this will be the main Lua thread,
/// for parameters given to a callback, this will be whatever Lua thread called the callback.
pub fn current_thread(&self) -> Thread {
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
assert_stack(state, 1);
ffi::lua_pushthread(state);
Thread(self.pop_ref())
}
}
/// Calls the given function with a `Scope` parameter, giving the function the ability to create
/// userdata and callbacks from rust types that are !Send or non-'static.
///
/// The lifetime of any function or userdata created through `Scope` lasts only until the
/// completion of this method call, on completion all such created values are automatically
/// dropped and Lua references to them are invalidated. If a script accesses a value created
/// through `Scope` outside of this method, a Lua error will result. Since we can ensure the
/// lifetime of values created through `Scope`, and we know that `Lua` cannot be sent to another
/// thread while `Scope` is live, it is safe to allow !Send datatypes and whose lifetimes only
/// outlive the scope lifetime.
///
/// Inside the scope callback, all handles created through Scope will share the same unique 'lua
/// lifetime of the parent `Lua`. This allows scoped and non-scoped values to be mixed in
/// API calls, which is very useful (e.g. passing a scoped userdata to a non-scoped function).
/// However, this also enables handles to scoped values to be trivially leaked from the given
/// callback. This is not dangerous, though! After the callback returns, all scoped values are
/// invalidated, which means that though references may exist, the Rust types backing them have
/// dropped. `Function` types will error when called, and `AnyUserData` will be typeless. It
/// would be impossible to prevent handles to scoped values from escaping anyway, since you
/// would always be able to smuggle them through Lua state.
pub fn scope<'lua, 'scope, R>(
&'lua self,
f: impl FnOnce(&Scope<'lua, 'scope>) -> Result<R>,
) -> Result<R>
where
'lua: 'scope,
{
f(&Scope::new(self))
}
/// Attempts to coerce a Lua value into a String in a manner consistent with Lua's internal
/// behavior.
///
/// To succeed, the value must be a string (in which case this is a no-op), an integer, or a
/// number.
pub fn coerce_string<'lua>(&'lua self, v: Value<'lua>) -> Result<Option<String<'lua>>> {
Ok(match v {
Value::String(s) => Some(s),
v => unsafe {
let state = self.state();
let _sg = StackGuard::new(state);
check_stack(state, 4)?;
self.push_value(v)?;
let res = if self.unlikely_memory_error() {
ffi::lua_tolstring(state, -1, ptr::null_mut())
} else {
protect_lua!(state, 1, 1, |state| {
ffi::lua_tolstring(state, -1, ptr::null_mut())
})?
};
if !res.is_null() {
Some(String(self.pop_ref()))
} else {
None
}
},
})
}
/// Attempts to coerce a Lua value into an integer in a manner consistent with Lua's internal
/// behavior.
///
/// To succeed, the value must be an integer, a floating point number that has an exact
/// representation as an integer, or a string that can be converted to an integer. Refer to the
/// Lua manual for details.
pub fn coerce_integer(&self, v: Value) -> Result<Option<Integer>> {
Ok(match v {
Value::Integer(i) => Some(i),
v => unsafe {
let state = self.state();
let _sg = StackGuard::new(state);
check_stack(state, 2)?;
self.push_value(v)?;
let mut isint = 0;
let i = ffi::lua_tointegerx(state, -1, &mut isint);
if isint == 0 {
None
} else {
Some(i)
}
},
})
}
/// Attempts to coerce a Lua value into a Number in a manner consistent with Lua's internal
/// behavior.
///
/// To succeed, the value must be a number or a string that can be converted to a number. Refer
/// to the Lua manual for details.
pub fn coerce_number(&self, v: Value) -> Result<Option<Number>> {
Ok(match v {
Value::Number(n) => Some(n),
v => unsafe {
let state = self.state();
let _sg = StackGuard::new(state);
check_stack(state, 2)?;
self.push_value(v)?;
let mut isnum = 0;
let n = ffi::lua_tonumberx(state, -1, &mut isnum);
if isnum == 0 {
None
} else {
Some(n)
}
},
})
}
/// Converts a value that implements `IntoLua` into a `Value` instance.
pub fn pack<'lua, T: IntoLua<'lua>>(&'lua self, t: T) -> Result<Value<'lua>> {
t.into_lua(self)
}
/// Converts a `Value` instance into a value that implements `FromLua`.
pub fn unpack<'lua, T: FromLua<'lua>>(&'lua self, value: Value<'lua>) -> Result<T> {
T::from_lua(value, self)
}
/// Converts a value that implements `IntoLuaMulti` into a `MultiValue` instance.
pub fn pack_multi<'lua, T: IntoLuaMulti<'lua>>(&'lua self, t: T) -> Result<MultiValue<'lua>> {
t.into_lua_multi(self)
}
/// Converts a `MultiValue` instance into a value that implements `FromLuaMulti`.
pub fn unpack_multi<'lua, T: FromLuaMulti<'lua>>(
&'lua self,
value: MultiValue<'lua>,
) -> Result<T> {
T::from_lua_multi(value, self)
}
/// Set a value in the Lua registry based on a string name.
///
/// This value will be available to rust from all `Lua` instances which share the same main
/// state.
pub fn set_named_registry_value<'lua, T>(&'lua self, name: &str, t: T) -> Result<()>
where
T: IntoLua<'lua>,
{
let state = self.state();
let t = t.into_lua(self)?;
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 5)?;
self.push_value(t)?;
rawset_field(state, ffi::LUA_REGISTRYINDEX, name)
}
}
/// Get a value from the Lua registry based on a string name.
///
/// Any Lua instance which shares the underlying main state may call this method to
/// get a value previously set by [`set_named_registry_value`].
///
/// [`set_named_registry_value`]: #method.set_named_registry_value
pub fn named_registry_value<'lua, T>(&'lua self, name: &str) -> Result<T>
where
T: FromLua<'lua>,
{
let state = self.state();
let value = unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 3)?;
let protect = !self.unlikely_memory_error();
push_string(state, name.as_bytes(), protect)?;
ffi::lua_rawget(state, ffi::LUA_REGISTRYINDEX);
self.pop_value()
};
T::from_lua(value, self)
}
/// Removes a named value in the Lua registry.
///
/// Equivalent to calling [`set_named_registry_value`] with a value of Nil.
///
/// [`set_named_registry_value`]: #method.set_named_registry_value
pub fn unset_named_registry_value(&self, name: &str) -> Result<()> {
self.set_named_registry_value(name, Nil)
}
/// Place a value in the Lua registry with an auto-generated key.
///
/// This value will be available to Rust from all `Lua` instances which share the same main
/// state.
///
/// Be warned, garbage collection of values held inside the registry is not automatic, see
/// [`RegistryKey`] for more details.
/// However, dropped [`RegistryKey`]s automatically reused to store new values.
///
/// [`RegistryKey`]: crate::RegistryKey
pub fn create_registry_value<'lua, T: IntoLua<'lua>>(&'lua self, t: T) -> Result<RegistryKey> {
let t = t.into_lua(self)?;
if t == Value::Nil {
// Special case to skip calling `luaL_ref` and use `LUA_REFNIL` instead
let unref_list = unsafe { (*self.extra.get()).registry_unref_list.clone() };
return Ok(RegistryKey::new(ffi::LUA_REFNIL, unref_list));
}
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 4)?;
self.push_value(t)?;
// Try to reuse previously allocated slot
let unref_list = (*self.extra.get()).registry_unref_list.clone();
let free_registry_id = mlua_expect!(unref_list.lock(), "unref list poisoned")
.as_mut()
.and_then(|x| x.pop());
if let Some(registry_id) = free_registry_id {
// It must be safe to replace the value without triggering memory error
ffi::lua_rawseti(state, ffi::LUA_REGISTRYINDEX, registry_id as Integer);
return Ok(RegistryKey::new(registry_id, unref_list));
}
// Allocate a new RegistryKey
let registry_id = if self.unlikely_memory_error() {
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX)
} else {
protect_lua!(state, 1, 0, |state| {
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX)
})?
};
Ok(RegistryKey::new(registry_id, unref_list))
}
}
/// Get a value from the Lua registry by its `RegistryKey`
///
/// Any Lua instance which shares the underlying main state may call this method to get a value
/// previously placed by [`create_registry_value`].
///
/// [`create_registry_value`]: #method.create_registry_value
pub fn registry_value<'lua, T: FromLua<'lua>>(&'lua self, key: &RegistryKey) -> Result<T> {
if !self.owns_registry_value(key) {
return Err(Error::MismatchedRegistryKey);
}
let state = self.state();
let value = match key.is_nil() {
true => Value::Nil,
false => unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 1)?;
let id = key.registry_id as Integer;
ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, id);
self.pop_value()
},
};
T::from_lua(value, self)
}
/// Removes a value from the Lua registry.
///
/// You may call this function to manually remove a value placed in the registry with
/// [`create_registry_value`]. In addition to manual `RegistryKey` removal, you can also call
/// [`expire_registry_values`] to automatically remove values from the registry whose
/// `RegistryKey`s have been dropped.
///
/// [`create_registry_value`]: #method.create_registry_value
/// [`expire_registry_values`]: #method.expire_registry_values
pub fn remove_registry_value(&self, key: RegistryKey) -> Result<()> {
if !self.owns_registry_value(&key) {
return Err(Error::MismatchedRegistryKey);
}
unsafe {
ffi::luaL_unref(self.state(), ffi::LUA_REGISTRYINDEX, key.take());
}
Ok(())
}
/// Replaces a value in the Lua registry by its `RegistryKey`.
///
/// See [`create_registry_value`] for more details.
///
/// [`create_registry_value`]: #method.create_registry_value
pub fn replace_registry_value<'lua, T: IntoLua<'lua>>(
&'lua self,
key: &RegistryKey,
t: T,
) -> Result<()> {
if !self.owns_registry_value(key) {
return Err(Error::MismatchedRegistryKey);
}
let t = t.into_lua(self)?;
if t == Value::Nil && key.is_nil() {
// Nothing to replace
return Ok(());
} else if t != Value::Nil && key.registry_id == ffi::LUA_REFNIL {
// We cannot update `LUA_REFNIL` slot
let err = "cannot replace nil value with non-nil".to_string();
return Err(Error::RuntimeError(err));
}
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 2)?;
let id = key.registry_id as Integer;
if t == Value::Nil {
self.push_value(Value::Integer(id))?;
key.set_nil(true);
} else {
self.push_value(t)?;
key.set_nil(false);
}
// It must be safe to replace the value without triggering memory error
ffi::lua_rawseti(state, ffi::LUA_REGISTRYINDEX, id);
}
Ok(())
}
/// Returns true if the given `RegistryKey` was created by a `Lua` which shares the underlying
/// main state with this `Lua` instance.
///
/// Other than this, methods that accept a `RegistryKey` will return
/// `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.get()).registry_unref_list };
Arc::ptr_eq(&key.unref_list, registry_unref_list)
}
/// Remove any registry values whose `RegistryKey`s have all been dropped.
///
/// Unlike normal handle values, `RegistryKey`s do not automatically remove themselves on Drop,
/// but you can call this method to remove any unreachable registry values not manually removed
/// by `Lua::remove_registry_value`.
pub fn expire_registry_values(&self) {
let state = self.state();
unsafe {
let mut unref_list = mlua_expect!(
(*self.extra.get()).registry_unref_list.lock(),
"unref list poisoned"
);
let unref_list = mem::replace(&mut *unref_list, Some(Vec::new()));
for id in mlua_expect!(unref_list, "unref list not set") {
ffi::luaL_unref(state, ffi::LUA_REGISTRYINDEX, id);
}
}
}
/// Sets or replaces an application data object of type `T`.
///
/// Application data could be accessed at any time by using [`Lua::app_data_ref()`] or [`Lua::app_data_mut()`]
/// methods where `T` is the data type.
///
/// # Panics
///
/// Panics if the app data container is currently borrowed.
///
/// # Examples
///
/// ```
/// use mlua::{Lua, Result};
///
/// fn hello(lua: &Lua, _: ()) -> Result<()> {
/// let mut s = lua.app_data_mut::<&str>().unwrap();
/// assert_eq!(*s, "hello");
/// *s = "world";
/// Ok(())
/// }
///
/// fn main() -> Result<()> {
/// let lua = Lua::new();
/// lua.set_app_data("hello");
/// lua.create_function(hello)?.call(())?;
/// let s = lua.app_data_ref::<&str>().unwrap();
/// assert_eq!(*s, "world");
/// Ok(())
/// }
/// ```
#[track_caller]
pub fn set_app_data<T: MaybeSend + 'static>(&self, data: T) -> Option<T> {
let extra = unsafe { &*self.extra.get() };
extra.app_data.insert(data)
}
/// Tries to set or replace an application data object of type `T`.
///
/// Returns:
/// - `Ok(Some(old_data))` if the data object of type `T` was successfully replaced.
/// - `Ok(None)` if the data object of type `T` was successfully inserted.
/// - `Err(data)` if the data object of type `T` was not inserted because the container is currently borrowed.
///
/// See [`Lua::set_app_data()`] for examples.
pub fn try_set_app_data<T: MaybeSend + 'static>(&self, data: T) -> StdResult<Option<T>, T> {
let extra = unsafe { &*self.extra.get() };
extra.app_data.try_insert(data)
}
/// Gets a reference to an application data object stored by [`Lua::set_app_data()`] of type `T`.
///
/// # Panics
///
/// Panics if the data object of type `T` is currently mutably borrowed. Multiple immutable reads
/// can be taken out at the same time.
#[track_caller]
pub fn app_data_ref<T: 'static>(&self) -> Option<AppDataRef<T>> {
let extra = unsafe { &*self.extra.get() };
extra.app_data.borrow()
}
/// Gets a mutable reference to an application data object stored by [`Lua::set_app_data()`] of type `T`.
///
/// # Panics
///
/// Panics if the data object of type `T` is currently borrowed.
#[track_caller]
pub fn app_data_mut<T: 'static>(&self) -> Option<AppDataRefMut<T>> {
let extra = unsafe { &*self.extra.get() };
extra.app_data.borrow_mut()
}
/// Removes an application data of type `T`.
///
/// # Panics
///
/// Panics if the app data container is currently borrowed.
#[track_caller]
pub fn remove_app_data<T: 'static>(&self) -> Option<T> {
let extra = unsafe { &*self.extra.get() };
extra.app_data.remove()
}
// Uses 2 stack spaces, does not call checkstack
pub(crate) unsafe fn push_value(&self, value: Value) -> Result<()> {
let state = self.state();
match value {
Value::Nil => {
ffi::lua_pushnil(state);
}
Value::Boolean(b) => {
ffi::lua_pushboolean(state, b as c_int);
}
Value::LightUserData(ud) => {
ffi::lua_pushlightuserdata(state, ud.0);
}
Value::Integer(i) => {
ffi::lua_pushinteger(state, i);
}
Value::Number(n) => {
ffi::lua_pushnumber(state, n);
}
#[cfg(feature = "luau")]
Value::Vector(x, y, z) => {
ffi::lua_pushvector(state, x, y, z);
}
Value::String(s) => {
self.push_ref(&s.0);
}
Value::Table(t) => {
self.push_ref(&t.0);
}
Value::Function(f) => {
self.push_ref(&f.0);
}
Value::Thread(t) => {
self.push_ref(&t.0);
}
Value::UserData(ud) => {
self.push_ref(&ud.0);
}
Value::Error(err) => {
let protect = !self.unlikely_memory_error();
push_gc_userdata(state, WrappedFailure::Error(err), protect)?;
}
}
Ok(())
}
// Uses 2 stack spaces, does not call checkstack
pub(crate) unsafe fn pop_value(&self) -> Value {
let state = self.state();
match ffi::lua_type(state, -1) {
ffi::LUA_TNIL => {
ffi::lua_pop(state, 1);
Nil
}
ffi::LUA_TBOOLEAN => {
let b = Value::Boolean(ffi::lua_toboolean(state, -1) != 0);
ffi::lua_pop(state, 1);
b
}
ffi::LUA_TLIGHTUSERDATA => {
let ud = Value::LightUserData(LightUserData(ffi::lua_touserdata(state, -1)));
ffi::lua_pop(state, 1);
ud
}
#[cfg(any(feature = "lua54", feature = "lua53"))]
ffi::LUA_TNUMBER => {
let v = if ffi::lua_isinteger(state, -1) != 0 {
Value::Integer(ffi::lua_tointeger(state, -1))
} else {
Value::Number(ffi::lua_tonumber(state, -1))
};
ffi::lua_pop(state, 1);
v
}
#[cfg(any(
feature = "lua52",
feature = "lua51",
feature = "luajit",
feature = "luau"
))]
ffi::LUA_TNUMBER => {
let n = ffi::lua_tonumber(state, -1);
ffi::lua_pop(state, 1);
match num_traits::cast(n) {
Some(i) if (n - (i as Number)).abs() < Number::EPSILON => Value::Integer(i),
_ => Value::Number(n),
}
}
#[cfg(feature = "luau")]
ffi::LUA_TVECTOR => {
let v = ffi::lua_tovector(state, -1);
mlua_debug_assert!(!v.is_null(), "vector is null");
let vec = Value::Vector(*v, *v.add(1), *v.add(2));
ffi::lua_pop(state, 1);
vec
}
ffi::LUA_TSTRING => Value::String(String(self.pop_ref())),
ffi::LUA_TTABLE => Value::Table(Table(self.pop_ref())),
ffi::LUA_TFUNCTION => Value::Function(Function(self.pop_ref())),
ffi::LUA_TUSERDATA => {
let wrapped_failure_mt_ptr = (*self.extra.get()).wrapped_failure_mt_ptr;
// We must prevent interaction with userdata types other than UserData OR a WrappedError.
// WrappedPanics are automatically resumed.
match get_gc_userdata::<WrappedFailure>(state, -1, wrapped_failure_mt_ptr).as_mut()
{
Some(WrappedFailure::Error(err)) => {
let err = err.clone();
ffi::lua_pop(state, 1);
Value::Error(err)
}
Some(WrappedFailure::Panic(panic)) => {
if let Some(panic) = panic.take() {
ffi::lua_pop(state, 1);
resume_unwind(panic);
}
// Previously resumed panic?
ffi::lua_pop(state, 1);
Nil
}
_ => Value::UserData(AnyUserData(self.pop_ref())),
}
}
ffi::LUA_TTHREAD => Value::Thread(Thread(self.pop_ref())),
#[cfg(feature = "luajit")]
ffi::LUA_TCDATA => {
ffi::lua_pop(state, 1);
// TODO: Fix this in a next major release
panic!("cdata objects cannot be handled by mlua yet");
}
_ => mlua_panic!("LUA_TNONE in pop_value"),
}
}
// Pushes a LuaRef value onto the stack, uses 1 stack space, does not call checkstack
pub(crate) unsafe fn push_ref(&self, lref: &LuaRef) {
assert!(
Arc::ptr_eq(&lref.lua.0, &self.0),
"Lua instance passed Value created from a different main Lua state"
);
ffi::lua_xpush(self.ref_thread(), self.state(), lref.index);
}
// Pops the topmost element of the stack and stores a reference to it. This pins the object,
// preventing garbage collection until the returned `LuaRef` is dropped.
//
// References are stored in the stack of a specially created auxiliary thread that exists only
// to store reference values. This is much faster than storing these in the registry, and also
// much more flexible and requires less bookkeeping than storing them directly in the currently
// used stack. The implementation is somewhat biased towards the use case of a relatively small
// number of short term references being created, and `RegistryKey` being used for long term
// references.
pub(crate) unsafe fn pop_ref(&self) -> LuaRef {
ffi::lua_xmove(self.state(), self.ref_thread(), 1);
let index = ref_stack_pop(self.extra.get());
LuaRef::new(self, index)
}
// Same as `pop_ref` but assumes the value is already on the reference thread
pub(crate) unsafe fn pop_ref_thread(&self) -> LuaRef {
let index = ref_stack_pop(self.extra.get());
LuaRef::new(self, index)
}
pub(crate) fn clone_ref(&self, lref: &LuaRef) -> LuaRef {
unsafe {
ffi::lua_pushvalue(self.ref_thread(), lref.index);
let index = ref_stack_pop(self.extra.get());
LuaRef::new(self, index)
}
}
pub(crate) fn drop_ref_index(&self, index: c_int) {
unsafe {
let ref_thread = self.ref_thread();
ffi::lua_pushnil(ref_thread);
ffi::lua_replace(ref_thread, index);
(*self.extra.get()).ref_free.push(index);
}
}
#[cfg(all(feature = "unstable", not(feature = "send")))]
pub(crate) fn adopt_owned_ref(&self, loref: crate::types::LuaOwnedRef) -> LuaRef {
assert!(
Arc::ptr_eq(&loref.inner, &self.0),
"Lua instance passed Value created from a different main Lua state"
);
let index = loref.index;
unsafe {
ptr::read(&loref.inner);
mem::forget(loref);
}
LuaRef::new(self, index)
}
unsafe fn register_userdata_metatable<'lua, T: 'static>(
&'lua self,
mut registry: UserDataRegistrar<'lua, T>,
) -> Result<Integer> {
let state = self.state();
let _sg = StackGuard::new(state);
check_stack(state, 13)?;
// Prepare metatable, add meta methods first and then meta fields
let metatable_nrec = registry.meta_methods.len() + registry.meta_fields.len();
#[cfg(feature = "async")]
let metatable_nrec = metatable_nrec + registry.async_meta_methods.len();
push_table(state, 0, metatable_nrec as c_int, true)?;
for (k, m) in registry.meta_methods {
self.push_value(Value::Function(self.create_callback(m)?))?;
rawset_field(state, -2, MetaMethod::validate(&k)?)?;
}
#[cfg(feature = "async")]
for (k, m) in registry.async_meta_methods {
self.push_value(Value::Function(self.create_async_callback(m)?))?;
rawset_field(state, -2, MetaMethod::validate(&k)?)?;
}
let mut has_name = false;
for (k, f) in registry.meta_fields {
has_name = has_name || k == "__name";
self.push_value(f(self, MultiValue::new())?.pop_front().unwrap())?;
rawset_field(state, -2, MetaMethod::validate(&k)?)?;
}
// Set `__name` if not provided
if !has_name {
let type_name = short_type_name::<T>();
push_string(state, type_name.as_bytes(), !self.unlikely_memory_error())?;
rawset_field(state, -2, "__name")?;
}
let metatable_index = ffi::lua_absindex(state, -1);
let mut extra_tables_count = 0;
let fields_nrec = registry.fields.len();
if fields_nrec > 0 {
// If __index is a table then update it inplace
let index_type = ffi::lua_getfield(state, metatable_index, cstr!("__index"));
match index_type {
ffi::LUA_TNIL | ffi::LUA_TTABLE => {
if index_type == ffi::LUA_TNIL {
// Create a new table
ffi::lua_pop(state, 1);
push_table(state, 0, fields_nrec as c_int, true)?;
}
for (k, f) in registry.fields {
self.push_value(f(self, MultiValue::new())?.pop_front().unwrap())?;
rawset_field(state, -2, &k)?;
}
rawset_field(state, metatable_index, "__index")?;
}
_ => {
// Propagate fields to the field getters
for (k, f) in registry.fields {
registry.field_getters.push((k, f))
}
}
}
}
let mut field_getters_index = None;
let field_getters_nrec = registry.field_getters.len();
if field_getters_nrec > 0 {
push_table(state, 0, field_getters_nrec as c_int, true)?;
for (k, m) in registry.field_getters {
self.push_value(Value::Function(self.create_callback(m)?))?;
rawset_field(state, -2, &k)?;
}
field_getters_index = Some(ffi::lua_absindex(state, -1));
extra_tables_count += 1;
}
let mut field_setters_index = None;
let field_setters_nrec = registry.field_setters.len();
if field_setters_nrec > 0 {
push_table(state, 0, field_setters_nrec as c_int, true)?;
for (k, m) in registry.field_setters {
self.push_value(Value::Function(self.create_callback(m)?))?;
rawset_field(state, -2, &k)?;
}
field_setters_index = Some(ffi::lua_absindex(state, -1));
extra_tables_count += 1;
}
let mut methods_index = None;
let methods_nrec = registry.methods.len();
#[cfg(feature = "async")]
let methods_nrec = methods_nrec + registry.async_methods.len();
if methods_nrec > 0 {
// If __index is a table then update it inplace
let index_type = ffi::lua_getfield(state, metatable_index, cstr!("__index"));
match index_type {
ffi::LUA_TTABLE => {} // Update the existing table
_ => {
// Create a new table
ffi::lua_pop(state, 1);
push_table(state, 0, methods_nrec as c_int, true)?;
}
}
for (k, m) in registry.methods {
self.push_value(Value::Function(self.create_callback(m)?))?;
rawset_field(state, -2, &k)?;
}
#[cfg(feature = "async")]
for (k, m) in registry.async_methods {
self.push_value(Value::Function(self.create_async_callback(m)?))?;
rawset_field(state, -2, &k)?;
}
match index_type {
ffi::LUA_TTABLE => {
ffi::lua_pop(state, 1); // All done
}
ffi::LUA_TNIL => {
rawset_field(state, metatable_index, "__index")?; // Set the new table as __index
}
_ => {
methods_index = Some(ffi::lua_absindex(state, -1));
extra_tables_count += 1;
}
}
}
init_userdata_metatable::<UserDataCell<T>>(
state,
metatable_index,
field_getters_index,
field_setters_index,
methods_index,
)?;
// Pop extra tables to get metatable on top of the stack
ffi::lua_pop(state, extra_tables_count);
let mt_ptr = ffi::lua_topointer(state, -1);
let id = protect_lua!(state, 1, 0, |state| {
ffi::luaL_ref(state, ffi::LUA_REGISTRYINDEX)
})?;
let type_id = TypeId::of::<T>();
(*self.extra.get()).registered_userdata.insert(type_id, id);
(*self.extra.get())
.registered_userdata_mt
.insert(mt_ptr, Some(type_id));
Ok(id as Integer)
}
#[inline]
pub(crate) unsafe fn register_raw_userdata_metatable(
&self,
ptr: *const c_void,
type_id: Option<TypeId>,
) {
(*self.extra.get())
.registered_userdata_mt
.insert(ptr, type_id);
}
#[inline]
pub(crate) unsafe fn deregister_raw_userdata_metatable(&self, ptr: *const c_void) {
(*self.extra.get()).registered_userdata_mt.remove(&ptr);
if (*self.extra.get()).last_checked_userdata_mt.0 == ptr {
(*self.extra.get()).last_checked_userdata_mt = (ptr::null(), None);
}
}
// Returns `TypeId` for the LuaRef, checking that it's a registered
// and not destructed UserData.
//
// Returns `None` if the userdata is registered but non-static.
pub(crate) unsafe fn get_userdata_type_id(&self, lref: &LuaRef) -> Result<Option<TypeId>> {
let ref_thread = self.ref_thread();
if ffi::lua_getmetatable(ref_thread, lref.index) == 0 {
return Err(Error::UserDataTypeMismatch);
}
let mt_ptr = ffi::lua_topointer(ref_thread, -1);
ffi::lua_pop(ref_thread, 1);
// Fast path to skip looking up the metatable in the map
let (last_mt, last_type_id) = (*self.extra.get()).last_checked_userdata_mt;
if last_mt == mt_ptr {
return Ok(last_type_id);
}
match (*self.extra.get()).registered_userdata_mt.get(&mt_ptr) {
Some(&type_id) if type_id == Some(TypeId::of::<DestructedUserdata>()) => {
Err(Error::UserDataDestructed)
}
Some(&type_id) => {
(*self.extra.get()).last_checked_userdata_mt = (mt_ptr, type_id);
Ok(type_id)
}
None => Err(Error::UserDataTypeMismatch),
}
}
// Pushes a LuaRef (userdata) value onto the stack, returning their `TypeId`.
// Uses 1 stack space, does not call checkstack.
pub(crate) unsafe fn push_userdata_ref(&self, lref: &LuaRef) -> Result<Option<TypeId>> {
let type_id = self.get_userdata_type_id(lref)?;
self.push_ref(lref);
Ok(type_id)
}
// Creates a Function out of a Callback containing a 'static Fn. This is safe ONLY because the
// Fn is 'static, otherwise it could capture 'lua arguments improperly. Without ATCs, we
// cannot easily deal with the "correct" callback type of:
//
// Box<for<'lua> Fn(&'lua Lua, MultiValue<'lua>) -> Result<MultiValue<'lua>>)>
//
// So we instead use a caller provided lifetime, which without the 'static requirement would be
// unsafe.
pub(crate) fn create_callback<'lua>(
&'lua self,
func: Callback<'lua, 'static>,
) -> Result<Function<'lua>> {
unsafe extern "C" fn call_callback(state: *mut ffi::lua_State) -> c_int {
// Normal functions can be scoped and therefore destroyed,
// so we need to check that the first upvalue is valid
let (upvalue, extra) = match ffi::lua_type(state, ffi::lua_upvalueindex(1)) {
ffi::LUA_TUSERDATA => {
let upvalue = get_userdata::<CallbackUpvalue>(state, ffi::lua_upvalueindex(1));
(upvalue, (*upvalue).extra.get())
}
_ => (ptr::null_mut(), ptr::null_mut()),
};
callback_error_ext(state, extra, |nargs| {
// Lua ensures that `LUA_MINSTACK` stack spaces are available (after pushing arguments)
if upvalue.is_null() {
return Err(Error::CallbackDestructed);
}
let lua: &Lua = mem::transmute((*extra).inner.assume_init_ref());
let _guard = StateGuard::new(&lua.0, state);
let mut args = MultiValue::new_or_pooled(lua);
args.reserve(nargs as usize);
for _ in 0..nargs {
args.push_front(lua.pop_value());
}
let func = &*(*upvalue).data;
let mut results = func(lua, args)?;
let nresults = results.len() as c_int;
check_stack(state, nresults)?;
for r in results.drain_all() {
lua.push_value(r)?;
}
MultiValue::return_to_pool(results, lua);
Ok(nresults)
})
}
let state = self.state();
unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 4)?;
let func = mem::transmute(func);
let extra = Arc::clone(&self.extra);
let protect = !self.unlikely_memory_error();
push_gc_userdata(state, CallbackUpvalue { data: func, extra }, protect)?;
if protect {
protect_lua!(state, 1, 1, fn(state) {
ffi::lua_pushcclosure(state, call_callback, 1);
})?;
} else {
ffi::lua_pushcclosure(state, call_callback, 1);
}
Ok(Function(self.pop_ref()))
}
}
#[cfg(feature = "async")]
pub(crate) fn create_async_callback<'lua>(
&'lua self,
func: AsyncCallback<'lua, 'static>,
) -> Result<Function<'lua>> {
#[cfg(any(
feature = "lua54",
feature = "lua53",
feature = "lua52",
feature = "luau"
))]
unsafe {
if !(*self.extra.get()).libs.contains(StdLib::COROUTINE) {
load_from_std_lib(self.main_state, StdLib::COROUTINE)?;
(*self.extra.get()).libs |= StdLib::COROUTINE;
}
}
unsafe extern "C" fn call_callback(state: *mut ffi::lua_State) -> c_int {
// Async functions cannot be scoped and therefore destroyed,
// so the first upvalue is always valid
let upvalue = get_userdata::<AsyncCallbackUpvalue>(state, ffi::lua_upvalueindex(1));
let extra = (*upvalue).extra.get();
callback_error_ext(state, extra, |nargs| {
// Lua ensures that `LUA_MINSTACK` stack spaces are available (after pushing arguments)
let lua: &Lua = mem::transmute((*extra).inner.assume_init_ref());
let _guard = StateGuard::new(&lua.0, state);
let mut args = MultiValue::new_or_pooled(lua);
args.reserve(nargs as usize);
for _ in 0..nargs {
args.push_front(lua.pop_value());
}
let func = &*(*upvalue).data;
let fut = func(lua, args);
let extra = Arc::clone(&(*upvalue).extra);
let protect = !lua.unlikely_memory_error();
push_gc_userdata(state, AsyncPollUpvalue { data: fut, extra }, protect)?;
if protect {
protect_lua!(state, 1, 1, fn(state) {
ffi::lua_pushcclosure(state, poll_future, 1);
})?;
} else {
ffi::lua_pushcclosure(state, poll_future, 1);
}
Ok(1)
})
}
unsafe extern "C" fn poll_future(state: *mut ffi::lua_State) -> c_int {
let upvalue = get_userdata::<AsyncPollUpvalue>(state, ffi::lua_upvalueindex(1));
let extra = (*upvalue).extra.get();
callback_error_ext(state, extra, |_| {
let lua: &Lua = mem::transmute((*extra).inner.assume_init_ref());
let _guard = StateGuard::new(&lua.0, state);
let fut = &mut (*upvalue).data;
let mut ctx = Context::from_waker(lua.waker());
match fut.as_mut().poll(&mut ctx) {
Poll::Pending => Ok(0),
Poll::Ready(results) => {
let mut results = results?;
let nresults = results.len();
lua.push_value(Value::Integer(nresults as _))?;
match nresults {
0 => Ok(1),
1 | 2 => {
// Fast path for 1 or 2 results without creating a table
for r in results.drain_all() {
lua.push_value(r)?;
}
MultiValue::return_to_pool(results, lua);
Ok(nresults as c_int + 1)
}
_ => {
lua.push_value(Value::Table(lua.create_sequence_from(results)?))?;
Ok(2)
}
}
}
}
})
}
let state = self.state();
let get_poll = unsafe {
let _sg = StackGuard::new(state);
check_stack(state, 4)?;
let func = mem::transmute(func);
let extra = Arc::clone(&self.extra);
let protect = !self.unlikely_memory_error();
let upvalue = AsyncCallbackUpvalue { data: func, extra };
push_gc_userdata(state, upvalue, protect)?;
if protect {
protect_lua!(state, 1, 1, fn(state) {
ffi::lua_pushcclosure(state, call_callback, 1);
})?;
} else {
ffi::lua_pushcclosure(state, call_callback, 1);
}
Function(self.pop_ref())
};
unsafe extern "C" fn unpack(state: *mut ffi::lua_State) -> c_int {
let len = ffi::lua_tointeger(state, 2);
ffi::luaL_checkstack(state, len as c_int, ptr::null());
for i in 1..=len {
ffi::lua_rawgeti(state, 1, i);
}
len as c_int
}
let coroutine = self.globals().get::<_, Table>("coroutine")?;
let env = self.create_table_with_capacity(0, 4)?;
env.set("get_poll", get_poll)?;
env.set("yield", coroutine.get::<_, Function>("yield")?)?;
unsafe {
env.set("unpack", self.create_c_function(unpack)?)?;
}
env.set("pending", {
LightUserData(&ASYNC_POLL_PENDING as *const u8 as *mut c_void)
})?;
self.load(
r#"
local poll = get_poll(...)
local pending, yield, unpack = pending, yield, unpack
while true do
local nres, res, res2 = poll()
if nres ~= nil then
if nres == 0 then
return
elseif nres == 1 then
return res
elseif nres == 2 then
return res, res2
else
return unpack(res, nres)
end
end
yield(pending)
end
"#,
)
.try_cache()
.set_name("__mlua_async_poll")
.set_environment(env)
.into_function()
}
#[cfg(feature = "async")]
#[inline]
pub(crate) unsafe fn waker(&self) -> &Waker {
(*self.extra.get()).waker.as_ref()
}
#[cfg(feature = "async")]
#[inline]
pub(crate) unsafe fn set_waker(&self, waker: NonNull<Waker>) -> NonNull<Waker> {
mem::replace(&mut (*self.extra.get()).waker, waker)
}
pub(crate) unsafe fn make_userdata<T>(&self, data: UserDataCell<T>) -> Result<AnyUserData>
where
T: UserData + 'static,
{
self.make_userdata_with_metatable(data, || {
// Check if userdata/metatable is already registered
let type_id = TypeId::of::<T>();
if let Some(&table_id) = (*self.extra.get()).registered_userdata.get(&type_id) {
return Ok(table_id as Integer);
}
// Create new metatable from UserData definition
let mut registry = UserDataRegistrar::new();
T::add_fields(&mut registry);
T::add_methods(&mut registry);
self.register_userdata_metatable(registry)
})
}
pub(crate) unsafe fn make_any_userdata<T>(&self, data: UserDataCell<T>) -> Result<AnyUserData>
where
T: 'static,
{
self.make_userdata_with_metatable(data, || {
// Check if userdata/metatable is already registered
let type_id = TypeId::of::<T>();
if let Some(&table_id) = (*self.extra.get()).registered_userdata.get(&type_id) {
return Ok(table_id as Integer);
}
// Create empty metatable
let registry = UserDataRegistrar::new();
self.register_userdata_metatable::<T>(registry)
})
}
unsafe fn make_userdata_with_metatable<T>(
&self,
data: UserDataCell<T>,
get_metatable_id: impl FnOnce() -> Result<Integer>,
) -> Result<AnyUserData> {
let state = self.state();
let _sg = StackGuard::new(state);
check_stack(state, 3)?;
// We push metatable first to ensure having correct metatable with `__gc` method
ffi::lua_pushnil(state);
ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, get_metatable_id()?);
let protect = !self.unlikely_memory_error();
#[cfg(not(feature = "lua54"))]
push_userdata(state, data, protect)?;
#[cfg(feature = "lua54")]
push_userdata_uv(state, data, USER_VALUE_MAXSLOT as c_int, protect)?;
ffi::lua_replace(state, -3);
ffi::lua_setmetatable(state, -2);
// Set empty environment for Lua 5.1
#[cfg(any(feature = "lua51", feature = "luajit"))]
if protect {
protect_lua!(state, 1, 1, fn(state) {
ffi::lua_newtable(state);
ffi::lua_setuservalue(state, -2);
})?;
} else {
ffi::lua_newtable(state);
ffi::lua_setuservalue(state, -2);
}
Ok(AnyUserData(self.pop_ref()))
}
#[cfg(not(feature = "luau"))]
fn disable_c_modules(&self) -> Result<()> {
let package: Table = self.globals().get("package")?;
package.set(
"loadlib",
self.create_function(|_, ()| -> Result<()> {
Err(Error::SafetyError(
"package.loadlib is disabled in safe mode".to_string(),
))
})?,
)?;
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
let searchers: Table = package.get("searchers")?;
#[cfg(any(feature = "lua51", feature = "luajit"))]
let searchers: Table = package.get("loaders")?;
let loader = self.create_function(|_, ()| Ok("\n\tcan't load C modules in safe mode"))?;
// The third and fourth searchers looks for a loader as a C library
searchers.raw_set(3, loader.clone())?;
searchers.raw_remove(4)?;
Ok(())
}
pub(crate) unsafe fn try_from_ptr(state: *mut ffi::lua_State) -> Option<Self> {
let extra = extra_data(state);
if extra.is_null() {
return None;
}
Some(Lua(Arc::clone((*extra).inner.assume_init_ref())))
}
#[inline]
pub(crate) unsafe fn unlikely_memory_error(&self) -> bool {
// MemoryInfo is empty in module mode so we cannot predict memory limits
(*self.extra.get())
.mem_state
.map(|x| x.as_ref().memory_limit() == 0)
.unwrap_or_default()
}
#[cfg(feature = "unstable")]
#[inline]
pub(crate) fn clone(&self) -> Arc<LuaInner> {
Arc::clone(&self.0)
}
}
impl LuaInner {
#[inline(always)]
pub(crate) fn state(&self) -> *mut ffi::lua_State {
self.state.load(Ordering::Relaxed)
}
#[cfg(feature = "luau")]
#[inline(always)]
pub(crate) fn main_state(&self) -> *mut ffi::lua_State {
self.main_state
}
#[inline(always)]
pub(crate) fn ref_thread(&self) -> *mut ffi::lua_State {
unsafe { (*self.extra.get()).ref_thread }
}
#[inline]
pub(crate) fn new_multivalue_from_pool(&self) -> MultiValue {
let extra = unsafe { &mut *self.extra.get() };
extra.multivalue_pool.pop().unwrap_or_default()
}
#[inline]
pub(crate) fn return_multivalue_to_pool(&self, mut multivalue: MultiValue) {
let extra = unsafe { &mut *self.extra.get() };
if extra.multivalue_pool.len() < MULTIVALUE_POOL_SIZE {
multivalue.clear();
extra
.multivalue_pool
.push(unsafe { mem::transmute(multivalue) });
}
}
}
impl ExtraData {
#[cfg(feature = "luau")]
#[inline]
pub(crate) fn mem_state(&self) -> NonNull<MemoryState> {
self.mem_state.unwrap()
}
}
struct StateGuard<'a>(&'a LuaInner, *mut ffi::lua_State);
impl<'a> StateGuard<'a> {
fn new(inner: &'a LuaInner, mut state: *mut ffi::lua_State) -> Self {
state = inner.state.swap(state, Ordering::Relaxed);
Self(inner, state)
}
}
impl<'a> Drop for StateGuard<'a> {
fn drop(&mut self) {
self.0.state.store(self.1, Ordering::Relaxed);
}
}
#[cfg(feature = "luau")]
unsafe fn extra_data(state: *mut ffi::lua_State) -> *mut ExtraData {
(*ffi::lua_callbacks(state)).userdata as *mut ExtraData
}
#[cfg(not(feature = "luau"))]
unsafe fn extra_data(state: *mut ffi::lua_State) -> *mut ExtraData {
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_TUSERDATA {
// `ExtraData` can be null only when Lua state is foreign.
// This case in used in `Lua::try_from_ptr()`.
ffi::lua_pop(state, 1);
return ptr::null_mut();
}
let extra_ptr = ffi::lua_touserdata(state, -1) as *mut Arc<UnsafeCell<ExtraData>>;
ffi::lua_pop(state, 1);
(*extra_ptr).get()
}
// Creates required entries in the metatable cache (see `util::METATABLE_CACHE`)
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);
#[cfg(feature = "async")]
{
cache.insert(TypeId::of::<AsyncCallback>(), 0);
cache.insert(TypeId::of::<AsyncCallbackUpvalue>(), 0);
cache.insert(TypeId::of::<AsyncPollUpvalue>(), 0);
cache.insert(TypeId::of::<Option<Waker>>(), 0);
}
}
// An optimized version of `callback_error` that does not allocate `WrappedFailure` userdata
// and instead reuses unsed values from previous calls (or allocates new).
unsafe fn callback_error_ext<F, R>(state: *mut ffi::lua_State, mut extra: *mut ExtraData, f: F) -> R
where
F: FnOnce(c_int) -> Result<R>,
{
if extra.is_null() {
extra = extra_data(state);
}
let nargs = ffi::lua_gettop(state);
enum PreallocatedFailure {
New(*mut WrappedFailure),
Existing(i32),
}
impl PreallocatedFailure {
unsafe fn reserve(state: *mut ffi::lua_State, extra: *mut ExtraData) -> Self {
match (*extra).wrapped_failure_pool.pop() {
Some(index) => PreallocatedFailure::Existing(index),
None => {
// We need to check stack for Luau in case when callback is called from interrupt
// See https://github.com/Roblox/luau/issues/446 and mlua #142 and #153
#[cfg(feature = "luau")]
ffi::lua_rawcheckstack(state, 2);
// Place it to the beginning of the stack
let ud = WrappedFailure::new_userdata(state);
ffi::lua_insert(state, 1);
PreallocatedFailure::New(ud)
}
}
}
unsafe fn r#use(
&self,
state: *mut ffi::lua_State,
extra: *mut ExtraData,
) -> *mut WrappedFailure {
let ref_thread = (*extra).ref_thread;
match *self {
PreallocatedFailure::New(ud) => {
ffi::lua_settop(state, 1);
ud
}
PreallocatedFailure::Existing(index) => {
ffi::lua_settop(state, 0);
#[cfg(feature = "luau")]
ffi::lua_rawcheckstack(state, 2);
ffi::lua_pushvalue(ref_thread, index);
ffi::lua_xmove(ref_thread, state, 1);
ffi::lua_pushnil(ref_thread);
ffi::lua_replace(ref_thread, index);
(*extra).ref_free.push(index);
ffi::lua_touserdata(state, -1) as *mut WrappedFailure
}
}
}
unsafe fn release(self, state: *mut ffi::lua_State, extra: *mut ExtraData) {
let ref_thread = (*extra).ref_thread;
match self {
PreallocatedFailure::New(_) => {
if (*extra).wrapped_failure_pool.len() < WRAPPED_FAILURE_POOL_SIZE {
ffi::lua_rotate(state, 1, -1);
ffi::lua_xmove(state, ref_thread, 1);
let index = ref_stack_pop(extra);
(*extra).wrapped_failure_pool.push(index);
} else {
ffi::lua_remove(state, 1);
}
}
PreallocatedFailure::Existing(index) => {
if (*extra).wrapped_failure_pool.len() < WRAPPED_FAILURE_POOL_SIZE {
(*extra).wrapped_failure_pool.push(index);
} else {
ffi::lua_pushnil(ref_thread);
ffi::lua_replace(ref_thread, index);
(*extra).ref_free.push(index);
}
}
}
}
}
// We cannot shadow Rust errors with Lua ones, so we need to reserve pre-allocated memory
// to store a wrapped failure (error or panic) *before* we proceed.
let prealloc_failure = PreallocatedFailure::reserve(state, extra);
match catch_unwind(AssertUnwindSafe(|| f(nargs))) {
Ok(Ok(r)) => {
// Return unused `WrappedFailure` to the pool
prealloc_failure.release(state, extra);
r
}
Ok(Err(err)) => {
let wrapped_error = prealloc_failure.r#use(state, extra);
// Build `CallbackError` with traceback
let traceback = if ffi::lua_checkstack(state, ffi::LUA_TRACEBACK_STACK) != 0 {
ffi::luaL_traceback(state, state, ptr::null(), 0);
let traceback = util::to_string(state, -1);
ffi::lua_pop(state, 1);
traceback
} else {
"<not enough stack space for traceback>".to_string()
};
let cause = Arc::new(err);
ptr::write(
wrapped_error,
WrappedFailure::Error(Error::CallbackError { traceback, cause }),
);
get_gc_metatable::<WrappedFailure>(state);
ffi::lua_setmetatable(state, -2);
ffi::lua_error(state)
}
Err(p) => {
let wrapped_panic = prealloc_failure.r#use(state, extra);
ptr::write(wrapped_panic, WrappedFailure::Panic(Some(p)));
get_gc_metatable::<WrappedFailure>(state);
ffi::lua_setmetatable(state, -2);
ffi::lua_error(state)
}
}
}
// Uses 3 stack spaces
unsafe fn load_from_std_lib(state: *mut ffi::lua_State, libs: StdLib) -> Result<()> {
#[inline(always)]
pub unsafe fn requiref(
state: *mut ffi::lua_State,
modname: &str,
openf: ffi::lua_CFunction,
glb: c_int,
) -> Result<()> {
let modname = mlua_expect!(CString::new(modname), "modname contains nil byte");
protect_lua!(state, 0, 1, |state| {
ffi::luaL_requiref(state, modname.as_ptr() as *const c_char, openf, glb)
})
}
#[cfg(feature = "luajit")]
struct GcGuard(*mut ffi::lua_State);
#[cfg(feature = "luajit")]
impl GcGuard {
fn new(state: *mut ffi::lua_State) -> Self {
// Stop collector during library initialization
unsafe { ffi::lua_gc(state, ffi::LUA_GCSTOP, 0) };
GcGuard(state)
}
}
#[cfg(feature = "luajit")]
impl Drop for GcGuard {
fn drop(&mut self) {
unsafe { ffi::lua_gc(self.0, ffi::LUA_GCRESTART, -1) };
}
}
// Stop collector during library initialization
#[cfg(feature = "luajit")]
let _gc_guard = GcGuard::new(state);
#[cfg(any(
feature = "lua54",
feature = "lua53",
feature = "lua52",
feature = "luau"
))]
{
if libs.contains(StdLib::COROUTINE) {
requiref(state, ffi::LUA_COLIBNAME, ffi::luaopen_coroutine, 1)?;
ffi::lua_pop(state, 1);
}
}
if libs.contains(StdLib::TABLE) {
requiref(state, ffi::LUA_TABLIBNAME, ffi::luaopen_table, 1)?;
ffi::lua_pop(state, 1);
}
#[cfg(not(feature = "luau"))]
if libs.contains(StdLib::IO) {
requiref(state, ffi::LUA_IOLIBNAME, ffi::luaopen_io, 1)?;
ffi::lua_pop(state, 1);
}
if libs.contains(StdLib::OS) {
requiref(state, ffi::LUA_OSLIBNAME, ffi::luaopen_os, 1)?;
ffi::lua_pop(state, 1);
}
if libs.contains(StdLib::STRING) {
requiref(state, ffi::LUA_STRLIBNAME, ffi::luaopen_string, 1)?;
ffi::lua_pop(state, 1);
}
#[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
{
if libs.contains(StdLib::UTF8) {
requiref(state, ffi::LUA_UTF8LIBNAME, ffi::luaopen_utf8, 1)?;
ffi::lua_pop(state, 1);
}
}
#[cfg(any(feature = "lua52", feature = "luau"))]
{
if libs.contains(StdLib::BIT) {
requiref(state, ffi::LUA_BITLIBNAME, ffi::luaopen_bit32, 1)?;
ffi::lua_pop(state, 1);
}
}
#[cfg(feature = "luajit")]
{
if libs.contains(StdLib::BIT) {
requiref(state, ffi::LUA_BITLIBNAME, ffi::luaopen_bit, 1)?;
ffi::lua_pop(state, 1);
}
}
if libs.contains(StdLib::MATH) {
requiref(state, ffi::LUA_MATHLIBNAME, ffi::luaopen_math, 1)?;
ffi::lua_pop(state, 1);
}
if libs.contains(StdLib::DEBUG) {
requiref(state, ffi::LUA_DBLIBNAME, ffi::luaopen_debug, 1)?;
ffi::lua_pop(state, 1);
}
#[cfg(not(feature = "luau"))]
if libs.contains(StdLib::PACKAGE) {
requiref(state, ffi::LUA_LOADLIBNAME, ffi::luaopen_package, 1)?;
ffi::lua_pop(state, 1);
}
#[cfg(feature = "luajit")]
{
if libs.contains(StdLib::JIT) {
requiref(state, ffi::LUA_JITLIBNAME, ffi::luaopen_jit, 1)?;
ffi::lua_pop(state, 1);
}
if libs.contains(StdLib::FFI) {
requiref(state, ffi::LUA_FFILIBNAME, ffi::luaopen_ffi, 1)?;
ffi::lua_pop(state, 1);
}
}
Ok(())
}
unsafe fn ref_stack_pop(extra: *mut ExtraData) -> c_int {
let extra = &mut *extra;
if let Some(free) = extra.ref_free.pop() {
ffi::lua_replace(extra.ref_thread, free);
return free;
}
// Try to grow max stack size
if extra.ref_stack_top >= extra.ref_stack_size {
let mut inc = extra.ref_stack_size; // Try to double stack size
while inc > 0 && ffi::lua_checkstack(extra.ref_thread, inc) == 0 {
inc /= 2;
}
if inc == 0 {
// Pop item on top of the stack to avoid stack leaking and successfully run destructors
// during unwinding.
ffi::lua_pop(extra.ref_thread, 1);
let top = extra.ref_stack_top;
// It is a user error to create enough references to exhaust the Lua max stack size for
// the ref thread.
panic!(
"cannot create a Lua reference, out of auxiliary stack space (used {top} slots)"
);
}
extra.ref_stack_size += inc;
}
extra.ref_stack_top += 1;
extra.ref_stack_top
}
#[cfg(test)]
mod assertions {
use super::*;
// Lua has lots of interior mutability, should not be RefUnwindSafe
static_assertions::assert_not_impl_any!(Lua: std::panic::RefUnwindSafe);
#[cfg(not(feature = "send"))]
static_assertions::assert_not_impl_any!(Lua: Send);
#[cfg(feature = "send")]
static_assertions::assert_impl_all!(Lua: Send);
}
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