⚡ perf: replace Vec<T> with Box<[T]> & refactor calculate_tfidf function (#603)

src/models/aggregation_models.rs

@@ -3,7 +3,6 @@
 
 use super::engine_models::EngineError;
 use serde::{Deserialize, Serialize};
-use smallvec::SmallVec;
 #[cfg(any(
     feature = "use-synonyms-search",
     feature = "use-non-static-synonyms-search"
@@ -23,7 +22,7 @@ pub struct SearchResult {
     /// The description of the search result.
     pub description: String,
     /// The names of the upstream engines from which this results were provided.
-    pub engine: SmallVec<[String; 0]>,
+    pub engine: Vec<String>,
     /// The td-tdf score of the result in regards to the title, url and description and the user's query
     pub relevance_score: f32,
 }
@@ -153,10 +152,10 @@ impl EngineErrorInfo {
 #[serde(rename_all = "camelCase")]
 pub struct SearchResults {
     /// Stores the individual serializable `SearchResult` struct into a vector of
-    pub results: Vec<SearchResult>,
+    pub results: Box<[SearchResult]>,
     /// Stores the information on which engines failed with their engine name
     /// and the type of error that caused it.
-    pub engine_errors_info: Vec<EngineErrorInfo>,
+    pub engine_errors_info: Box<[EngineErrorInfo]>,
     /// Stores the flag option which holds the check value that the following
     /// search query was disallowed when the safe search level set to 4 and it
     /// was present in the `Blocklist` file.
@@ -183,10 +182,10 @@ impl SearchResults {
     /// the search url.
     /// * `engine_errors_info` - Takes an array of structs which contains information regarding
     /// which engines failed with their names, reason and their severity color name.
-    pub fn new(results: Vec<SearchResult>, engine_errors_info: &[EngineErrorInfo]) -> Self {
+    pub fn new(results: Box<[SearchResult]>, engine_errors_info: Box<[EngineErrorInfo]>) -> Self {
         Self {
             results,
-            engine_errors_info: engine_errors_info.to_owned(),
+            engine_errors_info,
             disallowed: Default::default(),
             filtered: Default::default(),
             safe_search_level: Default::default(),
@@ -205,11 +204,11 @@ impl SearchResults {
     }
 
     /// A getter function that gets the value of `engine_errors_info`.
-    pub fn engine_errors_info(&mut self) -> Vec<EngineErrorInfo> {
+    pub fn engine_errors_info(&mut self) -> Box<[EngineErrorInfo]> {
         std::mem::take(&mut self.engine_errors_info)
     }
     /// A getter function that gets the value of `results`.
-    pub fn results(&mut self) -> Vec<SearchResult> {
+    pub fn results(&mut self) -> Box<[SearchResult]> {
         self.results.clone()
     }
 
@@ -254,27 +253,50 @@ fn calculate_tf_idf(
     let tf_idf = TfIdf::new(params);
     let tokener = Tokenizer::new(query, stop_words, Some(punctuation));
     let query_tokens = tokener.split_into_words();
-    let mut search_tokens = vec![];
 
-    for token in query_tokens {
+    #[cfg(any(
+        feature = "use-synonyms-search",
+        feature = "use-non-static-synonyms-search"
+    ))]
+    let mut extra_tokens = vec![];
+
+    let total_score: f32 = query_tokens
+        .iter()
+        .map(|token| {
             #[cfg(any(
                 feature = "use-synonyms-search",
                 feature = "use-non-static-synonyms-search"
             ))]
             {
                 // find some synonyms and add them to the search  (from wordnet or moby if feature is enabled)
-            let synonyms = synonyms(&token);
+                extra_tokens.extend(synonyms(token))
-            search_tokens.extend(synonyms)
-        }
-        search_tokens.push(token);
             }
 
-    let mut total_score = 0.0f32;
+            tf_idf.get_score(token)
-    for token in search_tokens.iter() {
+        })
-        total_score += tf_idf.get_score(token);
+        .sum();
-    }
 
-    let result = total_score / (search_tokens.len() as f32);
+    #[cfg(not(any(
+        feature = "use-synonyms-search",
+        feature = "use-non-static-synonyms-search"
+    )))]
+    let result = total_score / (query_tokens.len() as f32);
+
+    #[cfg(any(
+        feature = "use-synonyms-search",
+        feature = "use-non-static-synonyms-search"
+    ))]
+    let extra_total_score: f32 = extra_tokens
+        .iter()
+        .map(|token| tf_idf.get_score(token))
+        .sum();
+
+    #[cfg(any(
+        feature = "use-synonyms-search",
+        feature = "use-non-static-synonyms-search"
+    ))]
+    let result =
+        (extra_total_score + total_score) / ((query_tokens.len() + extra_tokens.len()) as f32);
 
     f32::from(!result.is_nan()) * result
 }