rust/crates/ide_ssr/src/from_comment.rs
2021-03-10 06:02:15 -08:00

33 lines
1.1 KiB
Rust

//! This module allows building an SSR MatchFinder by parsing the SSR rule
//! from a comment.
use ide_db::{
base_db::{FilePosition, FileRange, SourceDatabase},
RootDatabase,
};
use syntax::{
ast::{self, AstNode, AstToken},
TextRange,
};
use crate::MatchFinder;
/// Attempts to build an SSR MatchFinder from a comment at the given file
/// range. If successful, returns the MatchFinder and a TextRange covering
/// comment.
pub fn ssr_from_comment(db: &RootDatabase, frange: FileRange) -> Option<(MatchFinder, TextRange)> {
let comment = {
let file = db.parse(frange.file_id);
file.tree().syntax().token_at_offset(frange.range.start()).find_map(ast::Comment::cast)
}?;
let comment_text_without_prefix = comment.text().strip_prefix(comment.prefix()).unwrap();
let ssr_rule = comment_text_without_prefix.parse().ok()?;
let lookup_context = FilePosition { file_id: frange.file_id, offset: frange.range.start() };
let mut match_finder = MatchFinder::in_context(db, lookup_context, vec![]);
match_finder.add_rule(ssr_rule).ok()?;
Some((match_finder, comment.syntax().text_range()))
}