From 2d1d59acb7fa97abfbd9b91bf674dce3b2a25745 Mon Sep 17 00:00:00 2001
From: mposmta <postma.marin@protonmail.com>
Date: Thu, 26 Mar 2020 11:34:50 +0100
Subject: [PATCH] adds support for aligned cropping with cjk

---
 Cargo.lock                                  |  1 +
 meilisearch-http/Cargo.toml                 |  1 +
 meilisearch-http/src/helpers/meilisearch.rs | 19 ++++++++++++-------
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 1d19b9b5c..17569b566 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1081,6 +1081,7 @@ dependencies = [
  "main_error 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "meilisearch-core 0.9.0",
  "meilisearch-schema 0.9.0",
+ "meilisearch-tokenizer 0.9.0",
  "mime 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty-bytes 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/meilisearch-http/Cargo.toml b/meilisearch-http/Cargo.toml
index d98499643..219d6c51d 100644
--- a/meilisearch-http/Cargo.toml
+++ b/meilisearch-http/Cargo.toml
@@ -27,6 +27,7 @@ log = "0.4.8"
 main_error = "0.1.0"
 meilisearch-core = { path = "../meilisearch-core", version = "0.9.0" }
 meilisearch-schema = { path = "../meilisearch-schema", version = "0.9.0" }
+meilisearch-tokenizer = {path = "../meilisearch-tokenizer", version = "0.9.0"}
 mime = "0.3.16"
 pretty-bytes = "0.2.2"
 rand = "0.7.2"
diff --git a/meilisearch-http/src/helpers/meilisearch.rs b/meilisearch-http/src/helpers/meilisearch.rs
index 86e538f7e..8c823f33c 100644
--- a/meilisearch-http/src/helpers/meilisearch.rs
+++ b/meilisearch-http/src/helpers/meilisearch.rs
@@ -11,6 +11,7 @@ use log::error;
 use meilisearch_core::criterion::*;
 use meilisearch_core::settings::RankingRule;
 use meilisearch_core::{Highlight, Index, MainT, RankedMap};
+use meilisearch_tokenizer::is_cjk;
 use meilisearch_schema::{FieldId, Schema};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
@@ -372,19 +373,21 @@ pub struct SearchResult {
     pub query: String,
 }
 
+/// returns the start index and the length on the crop. 
 fn aligned_crop(text: &str, match_index: usize, context: usize) -> (usize, usize) {
-
-    if context == 0 {
-        return (match_index, text.chars().skip(match_index).take_while(|c| c.is_alphanumeric()).count());
-    }
+    let is_word_component = |c: &char| c.is_alphanumeric() && !is_cjk(*c);
 
     let word_end_index = |mut index| {
-        if let Some(true) = text.chars().nth(index - 1).map(|c| c.is_alphanumeric()) {
-            index += text.chars().skip(index).take_while(|c| c.is_alphanumeric()).count();
+        if text.chars().nth(index - 1).map_or(false, |c| is_word_component(&c)) {
+            index += text.chars().skip(index).take_while(is_word_component).count();
         }
         index
     };
 
+    if context == 0 {
+        // count need to be at least 1 for cjk queries to return something
+        return (match_index, 1 + text.chars().skip(match_index).take_while(is_word_component).count());
+    }
     let start = match match_index.saturating_sub(context) {
         n if n == 0 => n,
         n => word_end_index(n)
@@ -404,8 +407,10 @@ fn crop_text(
     let char_index = matches.peek().map(|m| m.char_index as usize).unwrap_or(0);
     let (start, count) = aligned_crop(text, char_index, context);
 
-    let text = text.chars().skip(start).take(count).collect::<String>().trim().into();
+    //TODO do something about the double allocation
+    let text = text.chars().skip(start).take(count).collect::<String>().trim().to_string();
 
+    // update matches index to match the new cropped text
     let matches = matches
         .take_while(|m| (m.char_index as usize) + (m.char_length as usize) <= start + (context * 2))
         .map(|match_| Highlight {