feat: Implement the excat match ranking rule

raptor-search/src/main.rs

@@ -12,7 +12,7 @@ use raptor::{load_map, DocIndexMap, RankedStream, LevBuilder};
 fn search(map: &DocIndexMap, lev_builder: &LevBuilder, query: &str) {
     let mut automatons = Vec::new();
     for query in query.split_whitespace() {
-        let lev = lev_builder.build_automaton(query);
+        let lev = lev_builder.get_automaton(query);
         automatons.push(lev);
     }
 
@@ -46,12 +46,11 @@ fn search(map: &DocIndexMap, lev_builder: &LevBuilder, query: &str) {
 fn main() {
     drop(env_logger::init());
 
-    let (elapsed, (lev_builder, map)) = measure_time(|| {
-        let lev_builder = LevBuilder::new();
-        let map = load_map("map.fst", "values.vecs").unwrap();
-        (lev_builder, map)
-    });
-    println!("Loaded in {}", elapsed);
+    let (elapsed, map) = measure_time(|| load_map("map.fst", "values.vecs").unwrap());
+    println!("{} to load the map", elapsed);
+
+    let (elapsed, lev_builder) = measure_time(|| LevBuilder::new());
+    println!("{} to load the levenshtein automaton", elapsed);
 
     match env::args().nth(1) {
         Some(query) => {

src/levenshtein.rs

@@ -15,13 +15,21 @@ impl LevBuilder {
         }
     }
 
-    pub fn build_automaton(&self, query: &str) -> DFA {
-        if query.len() <= 4 {
-            self.automatons[0].build_dfa(query)
+    pub fn get_automaton(&self, query: &str) -> Levenshtein {
+        let dfa = if query.len() <= 4 {
+            self.automatons[0].build_prefix_dfa(query)
         } else if query.len() <= 8 {
-            self.automatons[1].build_dfa(query)
+            self.automatons[1].build_prefix_dfa(query)
         } else {
-            self.automatons[2].build_dfa(query)
-        }
+            self.automatons[2].build_prefix_dfa(query)
+        };
+
+        Levenshtein { dfa, query_len: query.len() }
     }
 }
+
+#[derive(Clone)]
+pub struct Levenshtein {
+    pub dfa: DFA,
+    pub query_len: usize,
+}

src/lib.rs

@@ -83,6 +83,9 @@ pub struct Match {
     /// The index in the attribute is limited to a maximum of `2^32`
     /// this is because we index only the first 1000 words in an attribute.
     pub attribute_index: u32,
+
+    /// Whether the word that match is an exact match or a prefix.
+    pub is_exact: bool,
 }
 
 impl Match {
@@ -92,6 +95,7 @@ impl Match {
             distance: 0,
             attribute: 0,
             attribute_index: 0,
+            is_exact: false,
         }
     }
 
@@ -101,6 +105,7 @@ impl Match {
             distance: u8::max_value(),
             attribute: u8::max_value(),
             attribute_index: u32::max_value(),
+            is_exact: true,
         }
     }
 }

src/rank.rs

@@ -3,7 +3,7 @@ use std::collections::HashMap;
 use std::{mem, vec, iter};
 use DocIndexMap;
 use fst;
-use levenshtein_automata::DFA;
+use levenshtein::Levenshtein;
 use map::{
     OpWithStateBuilder, UnionWithState,
     StreamWithStateBuilder,
@@ -102,7 +102,12 @@ fn sum_of_words_position(lhs: &Document, rhs: &Document) -> Ordering {
 }
 
 fn exact(lhs: &Document, rhs: &Document) -> Ordering {
-    unimplemented!()
+    let contains_exact = |matches: &[Match]| matches.iter().any(|m| m.is_exact);
+    let key = |doc: &Document| -> usize {
+        GroupBy::new(&doc.matches, match_query_index).map(contains_exact).filter(|x| *x).count()
+    };
+
+    key(lhs).cmp(&key(rhs))
 }
 
 pub struct Pool {
@@ -155,6 +160,7 @@ impl IntoIterator for Pool {
             words_proximity,
             sum_of_words_attribute,
             sum_of_words_position,
+            exact,
         ];
 
         for (i, sort) in sorts.iter().enumerate() {
@@ -176,7 +182,7 @@ impl IntoIterator for Pool {
 pub enum RankedStream<'m, 'v> {
     Fed {
         inner: UnionWithState<'m, 'v, DocIndex, u32>,
-        automatons: Vec<DFA>,
+        automatons: Vec<Levenshtein>,
         pool: Pool,
     },
     Pours {
@@ -185,10 +191,10 @@ pub enum RankedStream<'m, 'v> {
 }
 
 impl<'m, 'v> RankedStream<'m, 'v> {
-    pub fn new(map: &'m DocIndexMap, values: &'v Values<DocIndex>, automatons: Vec<DFA>, limit: usize) -> Self {
+    pub fn new(map: &'m DocIndexMap, values: &'v Values<DocIndex>, automatons: Vec<Levenshtein>, limit: usize) -> Self {
         let mut op = OpWithStateBuilder::new(values);
 
-        for automaton in automatons.iter().cloned() {
+        for automaton in automatons.iter().map(|l| l.dfa.clone()) {
             let stream = map.as_map().search(automaton).with_state();
             op.push(stream);
         }
@@ -216,7 +222,7 @@ impl<'m, 'v, 'a> fst::Streamer<'a> for RankedStream<'m, 'v> {
             match self {
                 RankedStream::Fed { inner, automatons, pool } => {
                     match inner.next() {
-                        Some((_string, indexed_values)) => {
+                        Some((string, indexed_values)) => {
                             for iv in indexed_values {
 
                                 // TODO extend documents matches by batch of query_index
@@ -224,10 +230,8 @@ impl<'m, 'v, 'a> fst::Streamer<'a> for RankedStream<'m, 'v> {
                                 //      have an invalid distance *before* adding them
                                 //      to the matches of the documents and, that way, avoid a sort
 
-                                // let string = unsafe { str::from_utf8_unchecked(_string) };
-                                // println!("for {:15} ", string);
-
-                                let distance = automatons[iv.index].distance(iv.state).to_u8();
+                                let automaton = &automatons[iv.index];
+                                let distance = automaton.dfa.distance(iv.state).to_u8();
 
                                 // TODO remove the Pool system !
                                 //      this is an internal Pool rule but
@@ -240,6 +244,7 @@ impl<'m, 'v, 'a> fst::Streamer<'a> for RankedStream<'m, 'v> {
                                         distance: distance,
                                         attribute: di.attribute,
                                         attribute_index: di.attribute_index,
+                                        is_exact: string.len() == automaton.query_len,
                                     };
                                     matches.entry(di.document)
                                             .and_modify(|ms: &mut Vec<_>| ms.push(match_))
@@ -249,6 +254,7 @@ impl<'m, 'v, 'a> fst::Streamer<'a> for RankedStream<'m, 'v> {
                             }
                         },
                         None => {
+                            // TODO remove this when NLL are here !
                             transfert_pool = Some(mem::replace(pool, Pool::new(1, 1)));
                         },
                     }