use super::Scorer;
use crate::docset::TERMINATED;
use crate::query::explanation::does_not_match;
use crate::query::{EnableScoring, Explanation, Query, Weight};
use crate::{DocId, DocSet, Score, Searcher, SegmentReader};
#[derive(Clone, Debug)]
pub struct EmptyQuery;
impl Query for EmptyQuery {
fn weight(&self, _enable_scoring: EnableScoring<'_>) -> crate::Result<Box<dyn Weight>> {
Ok(Box::new(EmptyWeight))
}
fn count(&self, _searcher: &Searcher) -> crate::Result<usize> {
Ok(0)
}
}
pub struct EmptyWeight;
impl Weight for EmptyWeight {
fn scorer(&self, _reader: &SegmentReader, _boost: Score) -> crate::Result<Box<dyn Scorer>> {
Ok(Box::new(EmptyScorer))
}
fn explain(&self, _reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
Err(does_not_match(doc))
}
}
pub struct EmptyScorer;
impl DocSet for EmptyScorer {
fn advance(&mut self) -> DocId {
TERMINATED
}
fn doc(&self) -> DocId {
TERMINATED
}
fn size_hint(&self) -> u32 {
0
}
}
impl Scorer for EmptyScorer {
fn score(&mut self) -> Score {
0.0
}
}
#[cfg(test)]
mod tests {
use crate::docset::TERMINATED;
use crate::query::EmptyScorer;
use crate::DocSet;
#[test]
fn test_empty_scorer() {
let mut empty_scorer = EmptyScorer;
assert_eq!(empty_scorer.doc(), TERMINATED);
assert_eq!(empty_scorer.advance(), TERMINATED);
assert_eq!(empty_scorer.doc(), TERMINATED);
}
}