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state.rs
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state.rs
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use std::any::{Any, TypeId};
use std::cell::RefCell;
use std::collections::HashMap;
use std::fmt;
use std::mem;
use std::rc::Rc;
use crate::class;
use crate::def::{EnclosingRubyScope, Free};
use crate::eval::EvalContext;
use crate::fs::MrbFilesystem;
use crate::module;
use crate::sys::{self, DescribeState};
// NOTE: MrbState assumes that it it is stored in `mrb_state->ud` wrapped in a
// [`Rc`] with type [`Mrb`] as created by [`crate::interpreter`].
pub struct State {
pub mrb: *mut sys::mrb_state,
pub ctx: *mut sys::mrbc_context,
classes: HashMap<TypeId, Rc<RefCell<class::Spec>>>,
modules: HashMap<TypeId, Rc<RefCell<module::Spec>>>,
pub vfs: MrbFilesystem,
pub(crate) context_stack: Vec<EvalContext>,
pub num_set_regexp_capture_globals: usize,
symbol_cache: HashMap<String, sys::mrb_sym>,
}
impl State {
/// Create a new [`State`] from a [`sys::mrb_state`] and
/// [`sys::mrbc_context`] with an
/// [in memory virtual filesystem](MrbFilesystem).
pub fn new(mrb: *mut sys::mrb_state, ctx: *mut sys::mrbc_context, vfs: MrbFilesystem) -> Self {
Self {
mrb,
ctx,
classes: HashMap::default(),
modules: HashMap::default(),
vfs,
context_stack: vec![],
num_set_regexp_capture_globals: 0,
symbol_cache: HashMap::default(),
}
}
/// Close a [`State`] and free underlying mruby structs and memory.
pub fn close(self) {
drop(self)
}
/// Create a class definition bound to a Rust type `T`. Class definitions
/// have the same lifetime as the [`State`] because the class def owns the
/// `mrb_data_type` for the type, which must be long-lived. Class defs are
/// stored by [`TypeId`] of `T`.
///
/// Internally, [`class::Spec`]s are stored in an `Rc<RefCell<_>>` which
/// allows class specs to have multiple owners, such as being a super class
/// or an enclosing scope for a class or a module. To mutate the class spec,
/// call `borrow_mut` on the return value of this method to get a mutable
/// reference to the class spec.
///
/// Class specs can also be retrieved from the state after creation with
/// [`State::class_spec`].
///
/// The recommended pattern for using `def_class` looks like this:
///
/// ```rust
/// #[macro_use]
/// extern crate mruby;
///
/// use mruby::convert::FromMrb;
/// use mruby::def::{ClassLike, Define};
/// use mruby::sys;
/// use mruby::value::Value;
///
/// extern "C" fn value(mrb: *mut sys::mrb_state, _slf: sys::mrb_value) -> sys::mrb_value
/// {
/// let interp = unsafe { unwrap_interpreter!(mrb) };
/// Value::from_mrb(&interp, 29).inner()
/// }
///
/// fn main() {
/// let interp = mruby::interpreter().expect("mrb init");
/// let spec = {
/// let mut api = interp.borrow_mut();
/// let spec = api.def_class::<()>("Container", None, None);
/// spec.borrow_mut().add_method("value", value, sys::mrb_args_none());
/// spec.borrow_mut().add_self_method("value", value, sys::mrb_args_none());
/// spec.borrow_mut().mrb_value_is_rust_backed(true);
/// spec
/// };
/// spec.borrow().define(&interp).expect("class install");
/// }
/// ```
pub fn def_class<T: Any>(
&mut self,
name: &str,
enclosing_scope: Option<EnclosingRubyScope>,
free: Option<Free>,
) -> Rc<RefCell<class::Spec>> {
let spec = class::Spec::new(name, enclosing_scope, free);
let spec = Rc::new(RefCell::new(spec));
self.classes.insert(TypeId::of::<T>(), Rc::clone(&spec));
spec
}
/// Retrieve a class definition from the state bound to Rust type `T`.
///
/// This function returns `None` if type `T` has not had a class spec
/// registered for it using [`State::def_class`].
///
/// Internally, [`class::Spec`]s are stored in an `Rc<RefCell<_>>` which
/// allows class specs to have multiple owners, such as being a super class
/// or an enclosing scope for a class or a module. To mutate the class spec,
/// call `borrow_mut` on the return value of this method to get a mutable
/// reference to the class spec.
pub fn class_spec<T: Any>(&self) -> Option<Rc<RefCell<class::Spec>>> {
self.classes.get(&TypeId::of::<T>()).map(Rc::clone)
}
/// Create a module definition bound to a Rust type `T`. Module definitions
/// have the same lifetime as the [`State`]. Module defs are stored by
/// [`TypeId`] of `T`.
///
/// Internally, [`module::Spec`]s are stored in an `Rc<RefCell<_>>` which
/// allows module specs to have multiple owners, such as being an enclosing
/// scope for a class or a module. To mutate the module spec, call
/// `borrow_mut` on the return value of this method to get a mutable
/// reference to the module spec.
///
/// Module specs can also be retrieved from the state after creation with
/// [`State::module_spec`].
///
/// The recommended pattern for using `def_module` looks like this:
///
/// ```rust
/// #[macro_use]
/// extern crate mruby;
///
/// use mruby::convert::FromMrb;
/// use mruby::def::{ClassLike, Define};
/// use mruby::sys;
/// use mruby::value::Value;
///
/// extern "C" fn value(mrb: *mut sys::mrb_state, _slf: sys::mrb_value) -> sys::mrb_value
/// {
/// let interp = unsafe { unwrap_interpreter!(mrb) };
/// Value::from_mrb(&interp, 29).inner()
/// }
///
/// fn main() {
/// let interp = mruby::interpreter().expect("mrb init");
/// let spec = {
/// let mut api = interp.borrow_mut();
/// let spec = api.def_module::<()>("Container", None);
/// spec.borrow_mut().add_method("value", value, sys::mrb_args_none());
/// spec.borrow_mut().add_self_method("value", value, sys::mrb_args_none());
/// spec
/// };
/// spec.borrow().define(&interp).expect("class install");
/// }
/// ```
pub fn def_module<T: Any>(
&mut self,
name: &str,
enclosing_scope: Option<EnclosingRubyScope>,
) -> Rc<RefCell<module::Spec>> {
let spec = module::Spec::new(name, enclosing_scope);
let spec = Rc::new(RefCell::new(spec));
self.modules.insert(TypeId::of::<T>(), Rc::clone(&spec));
spec
}
/// Retrieve a module definition from the state bound to Rust type `T`.
///
/// This function returns `None` if type `T` has not had a class spec
/// registered for it using [`State::def_module`].
///
/// Internally, [`module::Spec`]s are stored in an `Rc<RefCell<_>>` which
/// allows module specs to have multiple owners, such as being an enclosing
/// scope for a class or a module. To mutate the module spec, call
/// `borrow_mut` on the return value of this method to get a mutable
/// reference to the module spec.
pub fn module_spec<T: Any>(&self) -> Option<Rc<RefCell<module::Spec>>> {
self.modules.get(&TypeId::of::<T>()).map(Rc::clone)
}
pub fn sym_intern(&mut self, sym: &str) -> sys::mrb_sym {
let mrb = self.mrb;
let interned = self
.symbol_cache
.entry(sym.to_owned())
.or_insert_with(|| unsafe {
sys::mrb_intern(mrb, sym.as_ptr() as *const i8, sym.len())
});
*interned
}
}
impl Drop for State {
fn drop(&mut self) {
unsafe {
// At this point, the only ref to the smart poitner wrapping the
// state is stored in the `mrb_state->ud` pointer. Rematerialize the
// `Rc`, set the userdata pointer to null, and drop the `Rc` to
// ensure no memory leaks. After this operation, `Rc::strong_count`
// will be 0 and the `Rc`, `RefCell`, and `State` will be
// deallocated.
let ptr = (*self.mrb).ud;
if !ptr.is_null() {
let ud = Rc::from_raw(ptr as *const RefCell<Self>);
// cleanup pointers
(*self.mrb).ud = std::ptr::null_mut();
mem::drop(ud);
}
// Free mrb data structures
sys::mrbc_context_free(self.mrb, self.ctx);
sys::mrb_close(self.mrb);
// Cleanup dangling pointers
self.ctx = std::ptr::null_mut();
self.mrb = std::ptr::null_mut();
};
}
}
impl fmt::Debug for State {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.mrb.debug())
}
}
impl fmt::Display for State {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.mrb.info())
}
}