ktrs_parser/builder/
sink.rs

1//! [`TreeSink`]: the tree builder `tree.rs` binds into, shared by a file and all of its
2//! chameleons so each lazy node is built in place instead of being copied out of a sub-tree.
3
4use ktrs_syntax::{Parse, SyntaxKind, TreeBuilder};
5
6use super::chameleon_cache::ChameleonCache;
7use super::psi_builder::PsiBuilder;
8
9#[derive(Default)]
10pub struct TreeSink {
11    tree: TreeBuilder,
12    cache: Option<ChameleonCache>,
13    pub(super) errors: Vec<String>,
14}
15
16impl TreeSink {
17    pub fn new() -> TreeSink {
18        TreeSink::default()
19    }
20
21    /// A sink sized for the tree of `builder`'s file, chameleons included.
22    pub(crate) fn for_file(builder: &PsiBuilder, cache: Option<ChameleonCache>) -> TreeSink {
23        // Chameleons re-cut the file's own lexemes, so leaves <= lexemes; nodes are fewer in practice.
24        let elements = 2 * builder.lexeme_count() + 1;
25        TreeSink { tree: TreeBuilder::with_capacity(elements, builder.text.len()), cache, errors: Vec::new() }
26    }
27
28    pub fn with_cache(cache: ChameleonCache) -> TreeSink {
29        TreeSink { cache: Some(cache), ..TreeSink::default() }
30    }
31
32    pub fn take_cache(&mut self) -> Option<ChameleonCache> {
33        self.cache.take()
34    }
35
36    pub fn finish(self) -> Parse {
37        Parse { tree: self.tree.finish().into(), error_messages: self.errors }
38    }
39
40    /// Emits the expanded chameleon `kind` over `text`: the cached subtree if there is one, else
41    /// whatever `build` emits (one root node of `kind`), remembered when it added no errors.
42    pub fn chameleon(&mut self, kind: SyntaxKind, text: &str, build: impl FnOnce(&mut TreeSink)) {
43        let Some(cache) = &self.cache else { return build(self) };
44        if let Some(subtree) = cache.get(kind, text) {
45            self.tree.push_tree(subtree);
46            return;
47        }
48        let (root, errors) = (self.tree.len(), self.errors.len());
49        build(self);
50        if self.errors.len() == errors {
51            let subtree = self.tree.extract(root);
52            self.cache.as_mut().expect("checked above").insert(subtree);
53        }
54    }
55
56    pub(super) fn token(&mut self, kind: SyntaxKind, text: &str) {
57        self.tree.token(kind, text);
58    }
59
60    pub(super) fn start_node(&mut self, kind: SyntaxKind) {
61        self.tree.start_node(kind);
62    }
63
64    pub(super) fn finish_node(&mut self) {
65        self.tree.finish_node();
66    }
67}
ktrs_parser/builder/sink.rs

ktrs_parser/builder/
sink.rs
