From e52da39839c9cd7e70da9cc74b1514a99e0122ba Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Mon, 3 Jul 2023 06:54:46 -0400
Subject: [PATCH] Fine tune network filter option anchor detection

The change allows to better parse AdGuard filters with `replace=`
option when the value to the `replace=` option contains dollar
sign character `$`. uBO will still reject these filters but will
better identify which dollar sign `$` is the real filter option
anchor.
---
 src/js/static-filtering-parser.js | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/js/static-filtering-parser.js b/src/js/static-filtering-parser.js
index 598dd7880dc39..c7035767ece6c 100644
--- a/src/js/static-filtering-parser.js
+++ b/src/js/static-filtering-parser.js
@@ -1387,9 +1387,17 @@ export class AstFilterParser {
         if ( j === -1 ) { return end; }
         if ( (j+1) === end ) { return end; }
         for (;;) {
-            if ( j !== start && s.charCodeAt(j-1) === 0x24 /* $ */ ) { return -1; }
-            const c = s.charCodeAt(j+1);
-            if ( c !== 0x29 /* ) */ && c !== 0x2F /* / */ && c !== 0x7C /* | */ ) { return j; }
+            const before = s.charCodeAt(j-1);
+            if ( j !== start && before === 0x24 /* $ */ ) { return -1; }
+            const after = s.charCodeAt(j+1);
+            if (
+                after !== 0x29 /* ) */ &&
+                after !== 0x2F /* / */ &&
+                after !== 0x7C /* | */ &&
+                before !== 0x5C /* \ */
+            ) {
+                return j;
+            }
             if ( j <= start ) { break; }
             j = s.lastIndexOf('$', j-1);
             if ( j === -1 ) { break; }