Improve cache ID to fix cache collisions, backwards compatible

Author: ManlyMarco

Shared_QuickAccessBox/ItemInfo.cs

@@ -36,12 +36,13 @@ public ItemInfo(int groupNo, int categoryNo, int localSlot, Info.ItemLoadInfo st
                 GUID = zipmodInfo.GUID;
                 ZipmodSlot = zipmodInfo.Slot;
                 DeveloperSearchString += "\v" + ZipmodSlot;
-                NewCacheId = MakeNewCacheId(groupNo, categoryNo, ZipmodSlot);
+                NewCacheId = MakeNewCacheId(groupNo, categoryNo, ZipmodSlot, zipmodInfo.GUID);
+                NewCacheIdShort = MakeNewCacheId(groupNo, categoryNo, ZipmodSlot, null);
             }
             else
             {
                 ZipmodSlot = -1;
-                NewCacheId = MakeNewCacheId(groupNo, categoryNo, LocalSlot);
+                NewCacheId = NewCacheIdShort = MakeNewCacheId(groupNo, categoryNo, LocalSlot, null);
             }
 
             if (zipmodFilename != null)
@@ -165,6 +166,11 @@ public ItemInfo(int groupNo, int categoryNo, int localSlot, Info.ItemLoadInfo st
         [Obsolete("Will be removed", true)]
         public string CacheId => OldCacheId;
         internal string NewCacheId { get; }
+        /// <summary>
+        /// Only for backwards compatibility, turns out the ID wasn't unique across zipmods
+        /// </summary>
+        [Obsolete]
+        internal string NewCacheIdShort { get; }
         [Obsolete]
         internal string OldCacheId { get; }
 
@@ -202,7 +208,7 @@ public void AddItem()
                 // Some modded items crash in Studio.OCIItem.UpdateColor()
             }
         }
-        
+
         private void UpdateCompositeStrings()
         {
             FullName = GroupName + "/" + CategoryName + "/" + ItemName;
@@ -221,10 +227,13 @@ private void UpdateCompositeStrings()
             SearchString = searchStr.Replace(' ', '_').ToLowerInvariant();
         }
 
-        private static string MakeNewCacheId(int groupNo, int categoryNo, int slotNo)
+        private static string MakeNewCacheId(int groupNo, int categoryNo, int slotNo, string guid)
         {
             // Sideloader generated local slot numbers start at 100000000, so real slot numbers should have at most 8 digits
-            return $"{groupNo:D8}-{categoryNo:D8}-{slotNo:D8}";
+            var str = $"{groupNo:D8}-{categoryNo:D8}-{slotNo:D8}";
+            if (guid != null)
+                str += $"-{Utils.GetHashCode(guid):X8}"; // Pretty much the same as using full guid string. Trimming hash to 4 bytes causes a lot of collisions.
+            return str;
         }
 
         [Obsolete]
@@ -256,7 +265,7 @@ public string ToDescriptionString()
 
             var sb = new StringBuilder();
             sb.AppendLine(FullName);
-            
+
             sb.Append($"Group = {GroupNo}  Category = {CategoryNo}");
             if (isZipmod) sb.Append($"  LocalSlot = {LocalSlot}  ZipmodSlot = {ZipmodSlot}");
             else sb.Append($"  Slot = {LocalSlot}");

Shared_QuickAccessBox/ItemInfoLoader.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Reflection;
 using System.Timers;
 using BepInEx;
@@ -95,6 +96,13 @@ public static void LoadItems()
             results.Sort((x, y) => string.Compare(x.FullName, y.FullName, StringComparison.Ordinal));
             ItemList = results;
 
+#if DEBUG
+#pragma warning disable CS0612
+            var oldGroups = results.GroupBy(x => x.OldCacheId).Count(x => x.Count() > 1);
+#pragma warning restore CS0612
+            var nowGroups = results.GroupBy(x => x.NewCacheId).Count(x => x.Count() > 1);
+            QuickAccessBox.Logger.LogInfo($"Cache collisions: old={oldGroups} new={nowGroups}");
+#endif
         }
 
         private static void LoadTranslationCache()

Shared_QuickAccessBox/ThumbnailCache.cs

@@ -37,13 +37,15 @@ public static Sprite GetThumbnail(ItemInfo info)
                 }
             }
 
-            _pngNameCache.TryGetValue(info.OldCacheId, out var pngPath);
+            _pngNameCache.TryGetValue(info.NewCacheId, out var pngPath);
             if (pngPath == null)
             {
                 // Fall back to old thumbnail names in case the mod wasn't updated
 #pragma warning disable CS0612
-                _pngNameCache.TryGetValue(info.NewCacheId, out pngPath);
+                _pngNameCache.TryGetValue(info.OldCacheId, out pngPath);
 #pragma warning restore CS0612
+                if (pngPath == null)
+                    _pngNameCache.TryGetValue(info.NewCacheIdShort, out pngPath);
             }
 
             var tex = Sideloader.Sideloader.GetPng(pngPath, TextureFormat.DXT5, false);

Shared_QuickAccessBox/Utils.cs

@@ -63,5 +63,30 @@ public static string MakeValidFileName(string text, char? replacement = '_', boo
 
         public static bool IsFavorited(this ItemInfo item) => QuickAccessBox.Instance.Favorited.Check(item.GUID, item.NewCacheId);
         public static bool IsBlacklisted(this ItemInfo item) => QuickAccessBox.Instance.Blacklisted.Check(item.GUID, item.NewCacheId);
+
+        /// <summary>
+        /// Repatable hash code for strings, not framework implementation dependent.
+        /// </summary>
+        public static unsafe int GetHashCode(string str)
+        {
+            fixed (char* chPtr = str)
+            {
+                int num1 = 352654597;
+                int num2 = num1;
+                int* numPtr = (int*)chPtr;
+                for (int length = str.Length; length > 0; length -= 4)
+                {
+                    num1 = (num1 << 5) + num1 + (num1 >> 27) ^ *numPtr;
+                    if (length > 2)
+                    {
+                        num2 = (num2 << 5) + num2 + (num2 >> 27) ^ numPtr[1];
+                        numPtr += 2;
+                    }
+                    else
+                        break;
+                }
+                return num1 + num2 * 1566083941;
+            }
+        }
     }
 }