init 2

LightlessSync/PlayerData/Data/FileReplacementDataComparer.cs

@@ -1,4 +1,7 @@
-using LightlessSync.API.Data;
+using LightlessSync.API.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
 
 namespace LightlessSync.PlayerData.Data;
 
@@ -13,37 +16,42 @@ public class FileReplacementDataComparer : IEqualityComparer<FileReplacementData
 
     public bool Equals(FileReplacementData? x, FileReplacementData? y)
     {
-        if (x == null || y == null) return false;
-        return x.Hash.Equals(y.Hash) && CompareHashSets(x.GamePaths.ToHashSet(StringComparer.Ordinal), y.GamePaths.ToHashSet(StringComparer.Ordinal)) && string.Equals(x.FileSwapPath, y.FileSwapPath, StringComparison.Ordinal);
+        if (ReferenceEquals(x, y))
+            return true;
+        if (x is null || y is null)
+            return false;
+
+        return string.Equals(x.Hash, y.Hash, StringComparison.OrdinalIgnoreCase)
+            && ComparePathSets(x.GamePaths, y.GamePaths)
+            && string.Equals(x.FileSwapPath ?? string.Empty, y.FileSwapPath ?? string.Empty, StringComparison.Ordinal);
     }
 
     public int GetHashCode(FileReplacementData obj)
     {
-        return HashCode.Combine(obj.Hash.GetHashCode(StringComparison.OrdinalIgnoreCase), GetOrderIndependentHashCode(obj.GamePaths), StringComparer.Ordinal.GetHashCode(obj.FileSwapPath));
+        if (obj is null)
+            return 0;
+
+        var hash = StringComparer.OrdinalIgnoreCase.GetHashCode(obj.Hash ?? string.Empty);
+        hash = HashCode.Combine(hash, GetSetHashCode(obj.GamePaths));
+        hash = HashCode.Combine(hash, StringComparer.OrdinalIgnoreCase.GetHashCode(obj.FileSwapPath ?? string.Empty));
+        return hash;
     }
 
-    private static bool CompareHashSets(HashSet<string> list1, HashSet<string> list2)
+    private static bool ComparePathSets(IEnumerable<string> first, IEnumerable<string> second)
     {
-        if (list1.Count != list2.Count)
-            return false;
-
-        for (int i = 0; i < list1.Count; i++)
-        {
-            if (!string.Equals(list1.ElementAt(i), list2.ElementAt(i), StringComparison.OrdinalIgnoreCase))
-                return false;
-        }
-
-        return true;
+        var left = new HashSet<string>(first ?? Enumerable.Empty<string>(), StringComparer.OrdinalIgnoreCase);
+        var right = new HashSet<string>(second ?? Enumerable.Empty<string>(), StringComparer.OrdinalIgnoreCase);
+        return left.SetEquals(right);
     }
 
-    private static int GetOrderIndependentHashCode<T>(IEnumerable<T> source) where T : notnull
+    private static int GetSetHashCode(IEnumerable<string> paths)
     {
         int hash = 0;
-        foreach (T element in source)
+        foreach (var element in paths ?? Enumerable.Empty<string>())
         {
-            hash = unchecked(hash +
-                EqualityComparer<T>.Default.GetHashCode(element));
+            hash = unchecked(hash + StringComparer.OrdinalIgnoreCase.GetHashCode(element));
         }
+
         return hash;
     }
 }