rhai/src/eval/cache.rs
2022-05-07 15:54:44 +08:00

69 lines
2.2 KiB
Rust

//! System caches.
use crate::func::CallableFunction;
use crate::{Identifier, StaticVec};
use std::collections::BTreeMap;
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
/// _(internals)_ An entry in a function resolution cache.
/// Exported under the `internals` feature only.
#[derive(Debug, Clone)]
pub struct FnResolutionCacheEntry {
/// Function.
pub func: CallableFunction,
/// Optional source.
pub source: Option<Box<Identifier>>,
}
/// _(internals)_ A function resolution cache.
/// Exported under the `internals` feature only.
///
/// [`FnResolutionCacheEntry`] is [`Box`]ed in order to pack as many entries inside a single B-Tree
/// level as possible.
pub type FnResolutionCache = BTreeMap<u64, Option<FnResolutionCacheEntry>>;
/// _(internals)_ A type containing system-wide caches.
/// Exported under the `internals` feature only.
///
/// The following caches are contained inside this type:
/// * A stack of [function resolution caches][FnResolutionCache]
#[derive(Debug, Clone)]
pub struct Caches(StaticVec<FnResolutionCache>);
impl Caches {
/// Create an empty [`Caches`].
#[inline(always)]
#[must_use]
pub const fn new() -> Self {
Self(StaticVec::new_const())
}
/// Get the number of function resolution cache(s) in the stack.
#[inline(always)]
#[must_use]
pub fn fn_resolution_caches_len(&self) -> usize {
self.0.len()
}
/// Get a mutable reference to the current function resolution cache.
#[inline]
#[must_use]
pub fn fn_resolution_cache_mut(&mut self) -> &mut FnResolutionCache {
if self.0.is_empty() {
// Push a new function resolution cache if the stack is empty
self.push_fn_resolution_cache();
}
self.0.last_mut().unwrap()
}
/// Push an empty function resolution cache onto the stack and make it current.
#[allow(dead_code)]
#[inline(always)]
pub fn push_fn_resolution_cache(&mut self) {
self.0.push(BTreeMap::new());
}
/// Rewind the function resolution caches stack to a particular size.
#[inline(always)]
pub fn rewind_fn_resolution_caches(&mut self, len: usize) {
self.0.truncate(len);
}
}