From 3516aa6d85049c20f34f4d5bec73a13ee0a70da8 Mon Sep 17 00:00:00 2001
From: Kamron Batman <3953314+kamronbatman@users.noreply.github.com>
Date: Mon, 20 Jul 2026 08:23:19 -0700
Subject: [PATCH] perf(advanced-search): span-based leaf evaluator for
 EvaluateBoolean

Custom LeafEvaluator<TState> delegate takes the leaf as ReadOnlySpan<char>
(Func<> can't take a ref struct) and threads caller state through, so the
property-test recursion allocates neither a per-leaf string nor a capturing
closure per entity.
---
 .../AdvancedSearch/AdvancedSearchUtilitiesTests.cs  |  3 ++-
 .../Advanced Search/AdvancedSearchThreadWorker.cs   |  2 +-
 .../Advanced Search/AdvancedSearchUtilities.cs      | 13 +++++++++----
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/Projects/UOContent.Tests/Tests/Engines/AdvancedSearch/AdvancedSearchUtilitiesTests.cs b/Projects/UOContent.Tests/Tests/Engines/AdvancedSearch/AdvancedSearchUtilitiesTests.cs
index 030f3f573..22923e53c 100644
--- a/Projects/UOContent.Tests/Tests/Engines/AdvancedSearch/AdvancedSearchUtilitiesTests.cs
+++ b/Projects/UOContent.Tests/Tests/Engines/AdvancedSearch/AdvancedSearchUtilitiesTests.cs
@@ -51,7 +51,8 @@ public class AdvancedSearchUtilitiesTests
     [InlineData("F|F", false)]
     public void EvaluateBoolean_Precedence(string expr, bool expected)
     {
-        var result = AdvancedSearchUtilities.EvaluateBoolean(expr, leaf => leaf == "T");
+        // State is unused here; the leaf evaluator just checks the span equals "T".
+        var result = AdvancedSearchUtilities.EvaluateBoolean(expr, 0, static (_, leaf) => leaf.SequenceEqual("T"));
         Assert.Equal(expected, result);
     }
 
diff --git a/Projects/UOContent/Engines/Advanced Search/AdvancedSearchThreadWorker.cs b/Projects/UOContent/Engines/Advanced Search/AdvancedSearchThreadWorker.cs
index a350cbdcd..a4a26c244 100644
--- a/Projects/UOContent/Engines/Advanced Search/AdvancedSearchThreadWorker.cs	
+++ b/Projects/UOContent/Engines/Advanced Search/AdvancedSearchThreadWorker.cs	
@@ -349,7 +349,7 @@ public class AdvancedSearchThreadWorker
     }
 
     private static bool EvaluateRecursive(IEntity entity, ReadOnlySpan<char> span) =>
-        AdvancedSearchUtilities.EvaluateBoolean(span, leaf => EvaluateSingleExpression(entity, leaf));
+        AdvancedSearchUtilities.EvaluateBoolean(span, entity, static (e, leaf) => EvaluateSingleExpression(e, leaf));
 
     private static bool EvaluateSingleExpression(IEntity entity, ReadOnlySpan<char> expression)
     {
diff --git a/Projects/UOContent/Engines/Advanced Search/AdvancedSearchUtilities.cs b/Projects/UOContent/Engines/Advanced Search/AdvancedSearchUtilities.cs
index adc793241..b1735a67e 100644
--- a/Projects/UOContent/Engines/Advanced Search/AdvancedSearchUtilities.cs	
+++ b/Projects/UOContent/Engines/Advanced Search/AdvancedSearchUtilities.cs	
@@ -375,22 +375,27 @@ public static class AdvancedSearchUtilities
         return false;
     }
 
+    // Evaluates one trimmed leaf atom against caller-supplied state. A custom delegate is required
+    // because ReadOnlySpan<char> cannot be a Func<> type argument; passing state avoids a per-call
+    // capturing closure, so the recursion allocates neither a string nor a closure.
+    internal delegate bool LeafEvaluator<in TState>(TState state, ReadOnlySpan<char> leaf);
+
     // OR ('|') binds looser than AND ('@'); split on the outermost OR first, then AND.
-    internal static bool EvaluateBoolean(ReadOnlySpan<char> expr, Func<string, bool> evalLeaf)
+    internal static bool EvaluateBoolean<TState>(ReadOnlySpan<char> expr, TState state, LeafEvaluator<TState> evalLeaf)
     {
         var orIndex = expr.IndexOf('|');
         if (orIndex != -1)
         {
-            return EvaluateBoolean(expr[..orIndex], evalLeaf) || EvaluateBoolean(expr[(orIndex + 1)..], evalLeaf);
+            return EvaluateBoolean(expr[..orIndex], state, evalLeaf) || EvaluateBoolean(expr[(orIndex + 1)..], state, evalLeaf);
         }
 
         var andIndex = expr.IndexOf('@');
         if (andIndex != -1)
         {
-            return EvaluateBoolean(expr[..andIndex], evalLeaf) && EvaluateBoolean(expr[(andIndex + 1)..], evalLeaf);
+            return EvaluateBoolean(expr[..andIndex], state, evalLeaf) && EvaluateBoolean(expr[(andIndex + 1)..], state, evalLeaf);
         }
 
-        return evalLeaf(expr.Trim().ToString());
+        return evalLeaf(state, expr.Trim());
     }
 
     private static int GetEnumSize(Type enumType) =>