From 21c1473e0c49b3b79a0ebe142c48f177992e9776 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Renault?= <clement@meilisearch.com>
Date: Tue, 14 Jan 2020 11:38:04 +0100
Subject: [PATCH] Introduce the distance data

---
 meilisearch-core/src/bucket_sort.rs |  4 ++--
 meilisearch-core/src/query_tree.rs  | 15 ++++++++++-----
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/meilisearch-core/src/bucket_sort.rs b/meilisearch-core/src/bucket_sort.rs
index 37eba6b57..935e81571 100644
--- a/meilisearch-core/src/bucket_sort.rs
+++ b/meilisearch-core/src/bucket_sort.rs
@@ -96,7 +96,7 @@ where
 
     let mut bare_matches = Vec::new();
     mk_arena!(arena);
-    for ((query, input), matches) in queries {
+    for ((query, input, distance), matches) in queries {
 
         let postings_list_view = PostingsListView::original(Rc::from(input), Rc::new(matches));
         // TODO optimize the filter by skipping docids that have already been seen
@@ -109,7 +109,7 @@ where
                 let bare_match = BareMatch {
                     document_id,
                     query_index: u16::try_from(query.id).unwrap(),
-                    distance: 0,
+                    distance: distance,
                     is_exact: true, // TODO where can I find this info?
                     postings_list: posting_list_index,
                 };
diff --git a/meilisearch-core/src/query_tree.rs b/meilisearch-core/src/query_tree.rs
index 5eae8c3bd..505d2613f 100644
--- a/meilisearch-core/src/query_tree.rs
+++ b/meilisearch-core/src/query_tree.rs
@@ -266,7 +266,8 @@ pub fn create_query_tree(
     Ok((operation, mapping))
 }
 
-pub type Postings<'o, 'txn> = HashMap<(&'o Query, Vec<u8>), Cow<'txn, Set<DocIndex>>>;
+pub type Distance = u8;
+pub type Postings<'o, 'txn> = HashMap<(&'o Query, Vec<u8>, Distance), Cow<'txn, Set<DocIndex>>>;
 pub type Cache<'o, 'txn> = HashMap<&'o Operation, Cow<'txn, Set<DocumentId>>>;
 
 pub struct QueryResult<'o, 'txn> {
@@ -372,7 +373,8 @@ pub fn traverse_query_tree<'o, 'txn>(
                 if *prefix && word.len() == 1 {
                     let prefix = [word.as_bytes()[0], 0, 0, 0];
                     let result = ctx.prefix_postings_lists.prefix_postings_list(reader, prefix)?.unwrap_or_default();
-                    postings.insert((query, word.clone().into_bytes()), result.matches);
+                    let distance = 0;
+                    postings.insert((query, word.clone().into_bytes(), distance), result.matches);
                     result.docids
                 } else {
                     let dfa = if *prefix { build_prefix_dfa(word) } else { build_dfa(word) };
@@ -387,9 +389,10 @@ pub fn traverse_query_tree<'o, 'txn>(
                     let before = Instant::now();
                     let mut docids = Vec::new();
                     while let Some(input) = stream.next() {
+                        let distance = dfa.eval(input).to_u8();
                         if let Some(result) = ctx.postings_lists.postings_list(reader, input)? {
                             docids.extend_from_slice(&result.docids);
-                            postings.insert((query, input.to_owned()), result.matches);
+                            postings.insert((query, input.to_owned(), distance), result.matches);
                         }
                     }
                     println!("{:3$}docids extend ({:?}) took {:.02?}", "", docids.len(), before.elapsed(), depth * 2);
@@ -414,9 +417,10 @@ pub fn traverse_query_tree<'o, 'txn>(
 
                 let mut docids = Vec::new();
                 while let Some(input) = stream.next() {
+                    let distance = dfa.eval(input).to_u8();
                     if let Some(result) = ctx.postings_lists.postings_list(reader, input)? {
                         docids.extend_from_slice(&result.docids);
-                        postings.insert((query, input.to_owned()), result.matches);
+                        postings.insert((query, input.to_owned(), distance), result.matches);
                     }
                 }
 
@@ -446,7 +450,8 @@ pub fn traverse_query_tree<'o, 'txn>(
                     println!("{:2$}docids construction took {:.02?}", "", before.elapsed(), depth * 2);
 
                     let matches = Cow::Owned(SetBuf::new(matches).unwrap());
-                    postings.insert((query, vec![]), matches);
+                    let distance = 0;
+                    postings.insert((query, vec![], distance), matches);
 
                     Cow::Owned(docids)
                 } else {