search: introduce hitmaker

meilisearch/src/search.rs

@@ -1,6 +1,6 @@
 use core::fmt;
 use std::cmp::min;
-use std::collections::{BTreeMap, BTreeSet, HashSet};
+use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
@@ -913,8 +913,13 @@ pub fn perform_search(
         show_ranking_score_details,
     };
 
-    let documents =
-        make_hits(index, &rtxn, format, matching_words, documents_ids, document_scores)?;
+    let documents = make_hits(
+        index,
+        &rtxn,
+        format,
+        matching_words,
+        documents_ids.iter().copied().zip(document_scores.iter()),
+    )?;
 
     let number_of_hits = min(candidates.len() as usize, max_total_hits);
     let hits_info = if is_finite_pagination {
@@ -1043,131 +1048,191 @@ impl RetrieveVectors {
     }
 }
 
-fn make_hits(
-    index: &Index,
-    rtxn: &RoTxn<'_>,
-    format: AttributesFormat,
-    matching_words: milli::MatchingWords,
-    documents_ids: Vec<u32>,
-    document_scores: Vec<Vec<ScoreDetails>>,
-) -> Result<Vec<SearchHit>, MeilisearchHttpError> {
-    let fields_ids_map = index.fields_ids_map(rtxn).unwrap();
-    let displayed_ids =
-        index.displayed_fields_ids(rtxn)?.map(|fields| fields.into_iter().collect::<BTreeSet<_>>());
+struct HitMaker<'a> {
+    index: &'a Index,
+    rtxn: &'a RoTxn<'a>,
+    fields_ids_map: FieldsIdsMap,
+    displayed_ids: BTreeSet<FieldId>,
+    vectors_fid: Option<FieldId>,
+    retrieve_vectors: RetrieveVectors,
+    to_retrieve_ids: BTreeSet<FieldId>,
+    embedding_configs: Vec<milli::index::IndexEmbeddingConfig>,
+    formatter_builder: MatcherBuilder<'a>,
+    formatted_options: BTreeMap<FieldId, FormatOptions>,
+    show_ranking_score: bool,
+    show_ranking_score_details: bool,
+    sort: Option<Vec<String>>,
+    show_matches_position: bool,
+}
 
-    let vectors_fid = fields_ids_map.id(milli::vector::parsed_vectors::RESERVED_VECTORS_FIELD_NAME);
+impl<'a> HitMaker<'a> {
+    pub fn tokenizer<'b>(
+        script_lang_map: &'b HashMap<milli::tokenizer::Script, Vec<milli::tokenizer::Language>>,
+        dictionary: Option<&'b [&'b str]>,
+        separators: Option<&'b [&'b str]>,
+    ) -> milli::tokenizer::Tokenizer<'b> {
+        let mut tokenizer_builder = TokenizerBuilder::default();
+        tokenizer_builder.create_char_map(true);
+        if !script_lang_map.is_empty() {
+            tokenizer_builder.allow_list(script_lang_map);
+        }
 
-    let vectors_is_hidden = match (&displayed_ids, vectors_fid) {
-        // displayed_ids is a wildcard, so `_vectors` can be displayed regardless of its fid
-        (None, _) => false,
-        // displayed_ids is a finite list, and `_vectors` cannot be part of it because it is not an existing field
-        (Some(_), None) => true,
-        // displayed_ids is a finit list, so hide if `_vectors` is not part of it
-        (Some(map), Some(vectors_fid)) => map.contains(&vectors_fid),
-    };
+        if let Some(separators) = separators {
+            tokenizer_builder.separators(separators);
+        }
 
-    let retrieve_vectors = if let RetrieveVectors::Retrieve = format.retrieve_vectors {
-        if vectors_is_hidden {
-            RetrieveVectors::Hide
+        if let Some(dictionary) = dictionary {
+            tokenizer_builder.words_dict(dictionary);
+        }
+
+        tokenizer_builder.into_tokenizer()
+    }
+
+    pub fn formatter_builder(
+        matching_words: milli::MatchingWords,
+        tokenizer: milli::tokenizer::Tokenizer<'_>,
+    ) -> MatcherBuilder<'_> {
+        let formatter_builder = MatcherBuilder::new(matching_words, tokenizer);
+
+        formatter_builder
+    }
+
+    pub fn new(
+        index: &'a Index,
+        rtxn: &'a RoTxn<'a>,
+        format: AttributesFormat,
+        mut formatter_builder: MatcherBuilder<'a>,
+    ) -> Result<Self, MeilisearchHttpError> {
+        formatter_builder.crop_marker(format.crop_marker);
+        formatter_builder.highlight_prefix(format.highlight_pre_tag);
+        formatter_builder.highlight_suffix(format.highlight_post_tag);
+
+        let fields_ids_map = index.fields_ids_map(rtxn)?;
+        let displayed_ids = index
+            .displayed_fields_ids(rtxn)?
+            .map(|fields| fields.into_iter().collect::<BTreeSet<_>>());
+
+        let vectors_fid =
+            fields_ids_map.id(milli::vector::parsed_vectors::RESERVED_VECTORS_FIELD_NAME);
+
+        let vectors_is_hidden = match (&displayed_ids, vectors_fid) {
+            // displayed_ids is a wildcard, so `_vectors` can be displayed regardless of its fid
+            (None, _) => false,
+            // displayed_ids is a finite list, and `_vectors` cannot be part of it because it is not an existing field
+            (Some(_), None) => true,
+            // displayed_ids is a finit list, so hide if `_vectors` is not part of it
+            (Some(map), Some(vectors_fid)) => map.contains(&vectors_fid),
+        };
+
+        let displayed_ids =
+            displayed_ids.unwrap_or_else(|| fields_ids_map.iter().map(|(id, _)| id).collect());
+
+        let retrieve_vectors = if let RetrieveVectors::Retrieve = format.retrieve_vectors {
+            if vectors_is_hidden {
+                RetrieveVectors::Hide
+            } else {
+                RetrieveVectors::Retrieve
+            }
         } else {
-            RetrieveVectors::Retrieve
-        }
-    } else {
-        format.retrieve_vectors
-    };
+            format.retrieve_vectors
+        };
 
-    let displayed_ids =
-        displayed_ids.unwrap_or_else(|| fields_ids_map.iter().map(|(id, _)| id).collect());
-    let fids = |attrs: &BTreeSet<String>| {
-        let mut ids = BTreeSet::new();
-        for attr in attrs {
-            if attr == "*" {
-                ids.clone_from(&displayed_ids);
-                break;
+        let fids = |attrs: &BTreeSet<String>| {
+            let mut ids = BTreeSet::new();
+            for attr in attrs {
+                if attr == "*" {
+                    ids.clone_from(&displayed_ids);
+                    break;
+                }
+
+                if let Some(id) = fields_ids_map.id(attr) {
+                    ids.insert(id);
+                }
             }
+            ids
+        };
+        let to_retrieve_ids: BTreeSet<_> = format
+            .attributes_to_retrieve
+            .as_ref()
+            .map(fids)
+            .unwrap_or_else(|| displayed_ids.clone())
+            .intersection(&displayed_ids)
+            .cloned()
+            .collect();
 
-            if let Some(id) = fields_ids_map.id(attr) {
-                ids.insert(id);
-            }
-        }
-        ids
-    };
-    let to_retrieve_ids: BTreeSet<_> = format
-        .attributes_to_retrieve
-        .as_ref()
-        .map(fids)
-        .unwrap_or_else(|| displayed_ids.clone())
-        .intersection(&displayed_ids)
-        .cloned()
-        .collect();
+        let attr_to_highlight = format.attributes_to_highlight.unwrap_or_default();
+        let attr_to_crop = format.attributes_to_crop.unwrap_or_default();
+        let formatted_options = compute_formatted_options(
+            &attr_to_highlight,
+            &attr_to_crop,
+            format.crop_length,
+            &to_retrieve_ids,
+            &fields_ids_map,
+            &displayed_ids,
+        );
 
-    let attr_to_highlight = format.attributes_to_highlight.unwrap_or_default();
-    let attr_to_crop = format.attributes_to_crop.unwrap_or_default();
-    let formatted_options = compute_formatted_options(
-        &attr_to_highlight,
-        &attr_to_crop,
-        format.crop_length,
-        &to_retrieve_ids,
-        &fields_ids_map,
-        &displayed_ids,
-    );
-    let mut tokenizer_builder = TokenizerBuilder::default();
-    tokenizer_builder.create_char_map(true);
-    let script_lang_map = index.script_language(rtxn)?;
-    if !script_lang_map.is_empty() {
-        tokenizer_builder.allow_list(&script_lang_map);
+        let embedding_configs = index.embedding_configs(rtxn)?;
+
+        Ok(Self {
+            index,
+            rtxn,
+            fields_ids_map,
+            displayed_ids,
+            vectors_fid,
+            retrieve_vectors,
+            to_retrieve_ids,
+            embedding_configs,
+            formatter_builder,
+            formatted_options,
+            show_ranking_score: format.show_ranking_score,
+            show_ranking_score_details: format.show_ranking_score_details,
+            show_matches_position: format.show_matches_position,
+            sort: format.sort,
+        })
     }
-    let separators = index.allowed_separators(rtxn)?;
-    let separators: Option<Vec<_>> =
-        separators.as_ref().map(|x| x.iter().map(String::as_str).collect());
-    if let Some(ref separators) = separators {
-        tokenizer_builder.separators(separators);
-    }
-    let dictionary = index.dictionary(rtxn)?;
-    let dictionary: Option<Vec<_>> =
-        dictionary.as_ref().map(|x| x.iter().map(String::as_str).collect());
-    if let Some(ref dictionary) = dictionary {
-        tokenizer_builder.words_dict(dictionary);
-    }
-    let mut formatter_builder = MatcherBuilder::new(matching_words, tokenizer_builder.build());
-    formatter_builder.crop_marker(format.crop_marker);
-    formatter_builder.highlight_prefix(format.highlight_pre_tag);
-    formatter_builder.highlight_suffix(format.highlight_post_tag);
-    let mut documents = Vec::new();
-    let embedding_configs = index.embedding_configs(rtxn)?;
-    let documents_iter = index.documents(rtxn, documents_ids)?;
-    for ((id, obkv), score) in documents_iter.into_iter().zip(document_scores.into_iter()) {
+
+    pub fn make_hit(
+        &self,
+        id: u32,
+        score: &[ScoreDetails],
+    ) -> Result<SearchHit, MeilisearchHttpError> {
+        let (_, obkv) =
+            self.index.iter_documents(self.rtxn, std::iter::once(id))?.next().unwrap()?;
+
         // First generate a document with all the displayed fields
-        let displayed_document = make_document(&displayed_ids, &fields_ids_map, obkv)?;
+        let displayed_document = make_document(&self.displayed_ids, &self.fields_ids_map, obkv)?;
 
         let add_vectors_fid =
-            vectors_fid.filter(|_fid| retrieve_vectors == RetrieveVectors::Retrieve);
+            self.vectors_fid.filter(|_fid| self.retrieve_vectors == RetrieveVectors::Retrieve);
 
         // select the attributes to retrieve
-        let attributes_to_retrieve = to_retrieve_ids
+        let attributes_to_retrieve = self
+            .to_retrieve_ids
             .iter()
             // skip the vectors_fid if RetrieveVectors::Hide
-            .filter(|fid| match vectors_fid {
+            .filter(|fid| match self.vectors_fid {
                 Some(vectors_fid) => {
-                    !(retrieve_vectors == RetrieveVectors::Hide && **fid == vectors_fid)
+                    !(self.retrieve_vectors == RetrieveVectors::Hide && **fid == vectors_fid)
                 }
                 None => true,
             })
             // need to retrieve the existing `_vectors` field if the `RetrieveVectors::Retrieve`
             .chain(add_vectors_fid.iter())
-            .map(|&fid| fields_ids_map.name(fid).expect("Missing field name"));
+            .map(|&fid| self.fields_ids_map.name(fid).expect("Missing field name"));
+
         let mut document =
             permissive_json_pointer::select_values(&displayed_document, attributes_to_retrieve);
 
-        if retrieve_vectors == RetrieveVectors::Retrieve {
+        if self.retrieve_vectors == RetrieveVectors::Retrieve {
             // Clippy is wrong
             #[allow(clippy::manual_unwrap_or_default)]
             let mut vectors = match document.remove("_vectors") {
                 Some(Value::Object(map)) => map,
                 _ => Default::default(),
             };
-            for (name, vector) in index.embeddings(rtxn, id)? {
-                let user_provided = embedding_configs
+            for (name, vector) in self.index.embeddings(self.rtxn, id)? {
+                let user_provided = self
+                    .embedding_configs
                     .iter()
                     .find(|conf| conf.name == name)
                     .is_some_and(|conf| conf.user_provided.contains(id));
@@ -1180,21 +1245,21 @@ fn make_hits(
 
         let (matches_position, formatted) = format_fields(
             &displayed_document,
-            &fields_ids_map,
-            &formatter_builder,
-            &formatted_options,
-            format.show_matches_position,
-            &displayed_ids,
+            &self.fields_ids_map,
+            &self.formatter_builder,
+            &self.formatted_options,
+            self.show_matches_position,
+            &self.displayed_ids,
         )?;
 
-        if let Some(sort) = format.sort.as_ref() {
+        if let Some(sort) = self.sort.as_ref() {
             insert_geo_distance(sort, &mut document);
         }
 
         let ranking_score =
-            format.show_ranking_score.then(|| ScoreDetails::global_score(score.iter()));
+            self.show_ranking_score.then(|| ScoreDetails::global_score(score.iter()));
         let ranking_score_details =
-            format.show_ranking_score_details.then(|| ScoreDetails::to_json_map(score.iter()));
+            self.show_ranking_score_details.then(|| ScoreDetails::to_json_map(score.iter()));
 
         let hit = SearchHit {
             document,
@@ -1203,7 +1268,38 @@ fn make_hits(
             ranking_score_details,
             ranking_score,
         };
-        documents.push(hit);
+
+        Ok(hit)
+    }
+}
+
+fn make_hits<'a>(
+    index: &Index,
+    rtxn: &RoTxn<'_>,
+    format: AttributesFormat,
+    matching_words: milli::MatchingWords,
+    documents_ids_scores: impl Iterator<Item = (u32, &'a Vec<ScoreDetails>)> + 'a,
+) -> Result<Vec<SearchHit>, MeilisearchHttpError> {
+    let mut documents = Vec::new();
+
+    let script_lang_map = index.script_language(rtxn)?;
+
+    let dictionary = index.dictionary(rtxn)?;
+    let dictionary: Option<Vec<_>> =
+        dictionary.as_ref().map(|x| x.iter().map(String::as_str).collect());
+    let separators = index.allowed_separators(rtxn)?;
+    let separators: Option<Vec<_>> =
+        separators.as_ref().map(|x| x.iter().map(String::as_str).collect());
+
+    let tokenizer =
+        HitMaker::tokenizer(&script_lang_map, dictionary.as_deref(), separators.as_deref());
+
+    let formatter_builder = HitMaker::formatter_builder(matching_words, tokenizer);
+
+    let hit_maker = HitMaker::new(index, rtxn, format, formatter_builder)?;
+
+    for (id, score) in documents_ids_scores {
+        documents.push(hit_maker.make_hit(id, score)?);
     }
     Ok(documents)
 }
@@ -1319,7 +1415,13 @@ pub fn perform_similar(
         show_ranking_score_details,
     };
 
-    let hits = make_hits(index, &rtxn, format, Default::default(), documents_ids, document_scores)?;
+    let hits = make_hits(
+        index,
+        &rtxn,
+        format,
+        Default::default(),
+        documents_ids.iter().copied().zip(document_scores.iter()),
+    )?;
 
     let max_total_hits = index
         .pagination_max_total_hits(&rtxn)
@@ -1492,10 +1594,10 @@ fn make_document(
     Ok(document)
 }
 
-fn format_fields<'a>(
+fn format_fields(
     document: &Document,
     field_ids_map: &FieldsIdsMap,
-    builder: &'a MatcherBuilder<'a>,
+    builder: &MatcherBuilder<'_>,
     formatted_options: &BTreeMap<FieldId, FormatOptions>,
     compute_matches: bool,
     displayable_ids: &BTreeSet<FieldId>,
@@ -1550,9 +1652,9 @@ fn format_fields<'a>(
     Ok((matches_position, document))
 }
 
-fn format_value<'a>(
+fn format_value(
     value: Value,
-    builder: &'a MatcherBuilder<'a>,
+    builder: &MatcherBuilder<'_>,
     format_options: Option<FormatOptions>,
     infos: &mut Vec<MatchBounds>,
     compute_matches: bool,