scarf_parser/preprocessor/
cache.rs

1// =======================================================================
2// cache.rs
3// =======================================================================
4//! A cache for storing data generated during preprocessing
5
6use crate::*;
7use elsa::FrozenVec;
8
9/// A cache for storing generated [`Span`]s and strings.
10///
11/// These objects are only meant to be used internal to the
12/// preprocessor. Since the CST only stores references to copy as
13/// little as possible, the [`PreprocessorCache`] stores new
14/// [`Span`]s and strings created as part of preprocessing (such
15/// as when referencing `` `include `` directives and elaborating
16/// preprocessor identifiers, respectively). Since the CST stores
17/// references to these, a [`PreprocessorCache`] used as part
18/// of preprocessing must be kept alive as long as the CST itself.
19pub struct PreprocessorCache<'a> {
20    spans: FrozenVec<Box<Span<'a>>>,
21    strings: FrozenVec<Box<str>>,
22}
23
24impl<'a> PreprocessorCache<'a> {
25    /// Store a [`Span`] for the cache's lifetime
26    pub fn retain_span(&self, span: Span<'a>) -> &Span<'a> {
27        self.spans.push_get(Box::new(span))
28    }
29    /// Store a [`String`] for the cache's lifetime
30    pub fn retain_string(&self, string: String) -> &str {
31        self.strings.push_get(string.into_boxed_str())
32    }
33    /// Create a new cache for storing preprocessor results
34    pub fn new() -> Self {
35        Self {
36            spans: FrozenVec::new(),
37            strings: FrozenVec::new(),
38        }
39    }
40}
scarf_parser/preprocessor/cache.rs

scarf_parser/preprocessor/
cache.rs
