Struct rlua::prelude::LuaRegistryKey

pub struct LuaRegistryKey { /* private fields */ }

An auto generated key into the Lua registry.

This is a handle to a value stored inside the Lua registry. Unlike the Table or Function handle types, this handle is Send + Sync + 'static and can be returned outside of a call to Lua::context. Also, rather than calling methods directly on it, you must instead retrieve the value first by calling Context::registry_value inside a call to Lua::context.

It is not automatically garbage collected on Drop, but it can be removed with Context::remove_registry_value, and instances not manually removed can be garbage collected with Context::expire_registry_values.

Be warned, If you place this into Lua via a UserData type or a rust callback and rely on Context::expire_registry_values, it is very easy to accidentally cause reference cycles that cannot be automatically collected. The Lua garbage collector is not aware of the registry handle pattern, so holding onto a RegistryKey inside Lua may lead to it never being dropped, and it if it is not droped, Context::expire_registry_values will never remove the value from the registry, leading to an uncollectable cycle. Instead of placing a RegistryKey into Lua and relying on it being automatically dropped, prefer APIs which the Lua garbage collector understands, such as UserData::set_i_user_value / UserData::get_i_user_value for UserData types and Function::bind for callbacks.

Trait Implementations

impl Debug for RegistryKey

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

Formats the value using the given formatter.

impl Drop for RegistryKey

fn drop(&mut self)

Executes the destructor for this type.