Struct mlua::AnyUserData

pub struct AnyUserData(/* private fields */);

Handle to an internal Lua userdata for any type that implements UserData.

Similar to std::any::Any, this provides an interface for dynamic type checking via the is and borrow methods.

Internally, instances are stored in a RefCell, to best match the mutable semantics of the Lua language.

Note

This API should only be used when necessary. Implementing UserData already allows defining methods which check the type and acquire a borrow behind the scenes.

Implementations

impl AnyUserData

pub fn is<T: 'static>(&self) -> bool

Checks whether the type of this userdata is T.

pub fn borrow<T: 'static>(&self) -> Result<UserDataRef<T>>

Borrow this userdata immutably if it is of type T.

Errors

Returns a UserDataBorrowError if the userdata is already mutably borrowed. Returns a UserDataTypeMismatch if the userdata is not of type T.

pub fn borrow_mut<T: 'static>(&self) -> Result<UserDataRefMut<T>>

Borrow this userdata mutably if it is of type T.

Errors

Returns a UserDataBorrowMutError if the userdata cannot be mutably borrowed. Returns a UserDataTypeMismatch if the userdata is not of type T.

pub fn take<T: 'static>(&self) -> Result<T>

Takes the value out of this userdata. Sets the special “destructed” metatable that prevents any further operations with this userdata.

Keeps associated user values unchanged (they will be collected by Lua’s GC).

pub fn set_user_value<V: IntoLua>(&self, v: V) -> Result<()>

Sets an associated value to this AnyUserData.

The value may be any Lua value whatsoever, and can be retrieved with user_value.

This is the same as calling set_nth_user_value with n set to 1.

pub fn user_value<V: FromLua>(&self) -> Result<V>

Returns an associated value set by set_user_value.

This is the same as calling nth_user_value with n set to 1.

pub fn set_nth_user_value<V: IntoLua>(&self, n: usize, v: V) -> Result<()>

Sets an associated nth value to this AnyUserData.

The value may be any Lua value whatsoever, and can be retrieved with nth_user_value. n starts from 1 and can be up to 65535.

This is supported for all Lua versions. In Lua 5.4 first 7 elements are stored in a most efficient way. For other Lua versions this functionality is provided using a wrapping table.

pub fn nth_user_value<V: FromLua>(&self, n: usize) -> Result<V>

Returns an associated nth value set by set_nth_user_value.

n starts from 1 and can be up to 65535.

This is supported for all Lua versions. In Lua 5.4 first 7 elements are stored in a most efficient way. For other Lua versions this functionality is provided using a wrapping table.

pub fn set_named_user_value<V: IntoLua>(&self, name: &str, v: V) -> Result<()>

Sets an associated value to this AnyUserData by name.

The value can be retrieved with named_user_value.

pub fn named_user_value<V: FromLua>(&self, name: &str) -> Result<V>

Returns an associated value by name set by set_named_user_value.

pub fn get_metatable(&self) -> Result<UserDataMetatable>

Returns a metatable of this UserData.

Returned UserDataMetatable object wraps the original metatable and provides safe access to its methods.

For T: 'static returned metatable is shared among all instances of type T.

pub fn to_pointer(&self) -> *const c_void

Converts this userdata to a generic C pointer.

There is no way to convert the pointer back to its original value.

Typically this function is used only for hashing and debug information.

impl AnyUserData

pub fn wrap<T: MaybeSend + 'static>(data: T) -> impl IntoLua

Wraps any Rust type, returning an opaque type that implements IntoLua trait.

This function uses Lua::create_any_userdata() under the hood.

Trait Implementations

impl AnyUserDataExt for AnyUserData

fn get<K: IntoLua, V: FromLua>(&self, key: K) -> Result<V>

Gets the value associated to key from the userdata, assuming it has __index metamethod.

fn set<K: IntoLua, V: IntoLua>(&self, key: K, value: V) -> Result<()>

Sets the value associated to key in the userdata, assuming it has __newindex metamethod.

fn call<A, R>(&self, args: A) -> Result<R>

where A: IntoLuaMulti, R: FromLuaMulti,

Calls the userdata as a function assuming it has __call metamethod.

fn call_async<A, R>(&self, args: A) -> impl Future<Output = Result<R>>

where A: IntoLuaMulti, R: FromLuaMulti,

Available on crate feature async only.

Asynchronously calls the userdata as a function assuming it has __call metamethod.

fn call_method<A, R>(&self, name: &str, args: A) -> Result<R>

where A: IntoLuaMulti, R: FromLuaMulti,

Calls the userdata method, assuming it has __index metamethod and a function associated to name.

fn call_async_method<A, R>( &self, name: &str, args: A, ) -> impl Future<Output = Result<R>>

where A: IntoLuaMulti, R: FromLuaMulti,

Available on crate feature async only.

Gets the function associated to key from the table and asynchronously executes it, passing the table itself along with args as function arguments and returning Future.

fn call_function<A, R>(&self, name: &str, args: A) -> Result<R>

where A: IntoLuaMulti, R: FromLuaMulti,

Gets the function associated to key from the table and executes it, passing args as function arguments.

fn call_async_function<A, R>( &self, name: &str, args: A, ) -> impl Future<Output = Result<R>>

where A: IntoLuaMulti, R: FromLuaMulti,

Available on crate feature async only.

Gets the function associated to key from the table and asynchronously executes it, passing args as function arguments and returning Future.

impl AsRef<AnyUserData> for AnyUserData

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for AnyUserData

fn clone(&self) -> AnyUserData

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AnyUserData

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FromLua for AnyUserData

fn from_lua(value: Value, _: &Lua) -> Result<AnyUserData>

Performs the conversion.

impl IntoLua for &AnyUserData

fn into_lua(self, _: &Lua) -> Result<Value>

Performs the conversion.

impl IntoLua for AnyUserData

fn into_lua(self, _: &Lua) -> Result<Value>

Performs the conversion.

impl PartialEq for AnyUserData

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for AnyUserData

fn serialize<S>(&self, serializer: S) -> StdResult<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.