From 69285b22d338e830b0f9b523982e1beead80021d Mon Sep 17 00:00:00 2001
From: Kerollmops <clement@meilisearch.com>
Date: Sat, 13 Jun 2020 11:16:02 +0200
Subject: [PATCH] Check that an edges combination contains results

---
 src/best_proximity.rs |  3 ++-
 src/lib.rs            | 32 +++++++++++++++++++++++++++-----
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/src/best_proximity.rs b/src/best_proximity.rs
index 192c387f1..49f90eb8e 100644
--- a/src/best_proximity.rs
+++ b/src/best_proximity.rs
@@ -102,7 +102,8 @@ pub struct BestProximity<F> {
 
 impl<F> BestProximity<F> {
     pub fn new(positions: Vec<Vec<u32>>, contains_documents: F) -> BestProximity<F> {
-        BestProximity { positions, best_proximity: 0, contains_documents }
+        let best_proximity = positions.len() as u32 - 1;
+        BestProximity { positions, best_proximity, contains_documents }
     }
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index 6918eccda..fee6831ef 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -119,13 +119,35 @@ impl Index {
 
         let mut documents = Vec::new();
 
-        for (proximity, mut positions) in BestProximity::new(positions, |_, _| true) {
-            // TODO we must ignore positions paths that gives nothing
-            if (proximity as usize) < words.len() - 1 {
-                eprintln!("Skipping too short proximities of {}.", proximity);
-                continue
+        let contains_documents = |(lword, lpos): (usize, u32), (rword, rpos)| {
+            use std::iter::once;
+
+            let left = (&words[lword], lpos);
+            let right = (&words[rword], rpos);
+
+            let mut intersect_docids: Option<RoaringBitmap> = None;
+            for (derived_words, pos) in once(left).chain(once(right)) {
+                let mut union_docids = RoaringBitmap::default();
+                // TODO re-enable the prefixes system
+                for word in derived_words.iter() {
+                    let mut key = word.clone();
+                    key.extend_from_slice(&pos.to_be_bytes());
+                    if let Some(attrs) = self.postings_ids.get(rtxn, &key).unwrap() {
+                        let right = RoaringBitmap::deserialize_from(attrs).unwrap();
+                        union_docids.union_with(&right);
+                    }
+                }
+
+                match &mut intersect_docids {
+                    Some(left) => left.intersect_with(&union_docids),
+                    None => intersect_docids = Some(union_docids),
+                }
             }
 
+            intersect_docids.map_or(false, |i| !i.is_empty())
+        };
+
+        for (proximity, mut positions) in BestProximity::new(positions, contains_documents) {
             positions.sort_unstable();
 
             let same_prox_before = Instant::now();