From 0e9c28f9c713421c23e80a3a55d5233dd36d08de Mon Sep 17 00:00:00 2001
From: Cashew <52880648+Scrub1492@users.noreply.github.com>
Date: Wed, 7 Feb 2024 17:54:49 +0700
Subject: [PATCH] Transformation performance optimizations (#645)

* perform transformation bounds

* fix wrong continue

* fix wrong undefined check

* regex performance

* suffixHeuristic

* escape RegExp

* fix escapeRegExp

* move destructuring after suffixHeuristic check

---------

Co-authored-by: Stefan Vukovic <stefanvukovic44@gmail.com>
Co-authored-by: Darius Jahandarie <djahandarie@gmail.com>
---
 ext/js/language/language-transformer.js      | 11 +++++++++--
 types/ext/language-transformer-internal.d.ts |  1 +
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/ext/js/language/language-transformer.js b/ext/js/language/language-transformer.js
index c9e261eae4..7ad1895f5f 100644
--- a/ext/js/language/language-transformer.js
+++ b/ext/js/language/language-transformer.js
@@ -15,6 +15,8 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import {escapeRegExp} from '../core/utilities.js';
+
 export class LanguageTransformer {
     constructor() {
         /** @type {number} */
@@ -65,7 +67,9 @@ export class LanguageTransformer {
                     conditionsOut: conditionFlagsOut
                 });
             }
-            transforms2.push({name, rules: rules2});
+            const suffixes = rules.map((rule) => rule.suffixIn);
+            const suffixHeuristic = new RegExp(`(${suffixes.map((suffix) => escapeRegExp(suffix)).join('|')})$`);
+            transforms2.push({name, rules: rules2, suffixHeuristic});
         }
 
         this._nextFlagIndex = nextFlagIndex;
@@ -133,7 +137,10 @@ export class LanguageTransformer {
         const results = [this._createTransformedText(sourceText, 0, [])];
         for (let i = 0; i < results.length; ++i) {
             const {text, conditions, trace} = results[i];
-            for (const {name, rules} of this._transforms) {
+            for (const transform of this._transforms) {
+                if (!transform.suffixHeuristic.test(text)) { continue; }
+
+                const {name, rules} = transform;
                 for (let j = 0, jj = rules.length; j < jj; ++j) {
                     const rule = rules[j];
                     if (!LanguageTransformer.conditionsMatch(conditions, rule.conditionsIn)) { continue; }
diff --git a/types/ext/language-transformer-internal.d.ts b/types/ext/language-transformer-internal.d.ts
index cb0899e91f..c186eeca4b 100644
--- a/types/ext/language-transformer-internal.d.ts
+++ b/types/ext/language-transformer-internal.d.ts
@@ -18,6 +18,7 @@
 export type Transform = {
     name: string;
     rules: Rule[];
+    suffixHeuristic: RegExp;
 };
 
 export type Rule = {