wip

Dalamud/Game/Inventory/GameInventory.cs

@@ -1,4 +1,6 @@
-using System.Collections.Generic;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
 
 using Dalamud.Configuration.Internal;
 using Dalamud.Game.Inventory.InventoryChangeArgsTypes;
@@ -22,21 +24,20 @@ internal class GameInventory : IDisposable, IServiceType, IGameInventory
 {
     private static readonly ModuleLog Log = new("GameInventory");
 
-    private readonly List<InventoryEventArgs> allEvents = new();
     private readonly List<InventoryItemAddedArgs> addedEvents = new();
     private readonly List<InventoryItemRemovedArgs> removedEvents = new();
     private readonly List<InventoryItemChangedArgs> changedEvents = new();
     private readonly List<InventoryItemMovedArgs> movedEvents = new();
-    
+
     [ServiceManager.ServiceDependency]
     private readonly Framework framework = Service<Framework>.Get();
-    
+
     [ServiceManager.ServiceDependency]
     private readonly DalamudConfiguration dalamudConfiguration = Service<DalamudConfiguration>.Get();
 
     private readonly GameInventoryType[] inventoryTypes;
     private readonly GameInventoryItem[]?[] inventoryItems;
-    
+
     [ServiceManager.ServiceConstructor]
     private GameInventory()
     {
@@ -59,10 +60,10 @@ internal class GameInventory : IDisposable, IServiceType, IGameInventory
     public event IGameInventory.InventoryChangedDelegate? ItemRemoved;
 
     /// <inheritdoc/>
-    public event IGameInventory.InventoryChangedDelegate? ItemMoved;
+    public event IGameInventory.InventoryChangedDelegate? ItemChanged;
 
     /// <inheritdoc/>
-    public event IGameInventory.InventoryChangedDelegate? ItemChanged;
+    public event IGameInventory.InventoryChangedDelegate? ItemMoved;
 
     /// <inheritdoc/>
     public void Dispose()
@@ -111,7 +112,7 @@ internal class GameInventory : IDisposable, IServiceType, IGameInventory
             Log.Error(e, "Exception during {argType} callback", arg.Type);
         }
     }
-    
+
     private void OnFrameworkUpdate(IFramework framework1)
     {
         for (var i = 0; i < this.inventoryTypes.Length; i++)
@@ -152,124 +153,135 @@ internal class GameInventory : IDisposable, IServiceType, IGameInventory
         }
 
         // Was there any change? If not, stop further processing.
-        // Note that...
+        // Note that this.movedEvents is not checked; it will be populated after this check.
-        // * this.movedEvents is not checked; it will be populated after this check.
-        // * this.allEvents is not checked; it is a temporary list to be used after this check.
         if (this.addedEvents.Count == 0 && this.removedEvents.Count == 0 && this.changedEvents.Count == 0)
             return;
 
-        try
+        // Broadcast InventoryChangedRaw.
+        InvokeSafely(
+            this.InventoryChangedRaw,
+            new DeferredReadOnlyCollection<InventoryEventArgs>(
+                this.addedEvents.Count +
+                this.removedEvents.Count +
+                this.changedEvents.Count,
+                () => Array.Empty<InventoryEventArgs>()
+                           .Concat(this.addedEvents)
+                           .Concat(this.removedEvents)
+                           .Concat(this.changedEvents)));
+
+        // Resolve changelog for item moved, from 1 added + 1 removed event.
+        for (var iAdded = this.addedEvents.Count - 1; iAdded >= 0; --iAdded)
         {
-            // Broadcast InventoryChangedRaw, if necessary.
+            var added = this.addedEvents[iAdded];
-            if (this.InventoryChangedRaw is not null)
+            for (var iRemoved = this.removedEvents.Count - 1; iRemoved >= 0; --iRemoved)
             {
-                this.allEvents.Clear();
+                var removed = this.removedEvents[iRemoved];
-                this.allEvents.EnsureCapacity(
+                if (added.Item.ItemId != removed.Item.ItemId)
-                    this.addedEvents.Count
+                    continue;
-                    + this.removedEvents.Count
-                    + this.changedEvents.Count);
-                this.allEvents.AddRange(this.addedEvents);
-                this.allEvents.AddRange(this.removedEvents);
-                this.allEvents.AddRange(this.changedEvents);
-                InvokeSafely(this.InventoryChangedRaw, this.allEvents);
-            }
 
-            // Resolve changelog for item moved, from 1 added + 1 removed event.
+                this.movedEvents.Add(new(removed, added));
-            for (var iAdded = this.addedEvents.Count - 1; iAdded >= 0; --iAdded)
+
+                // Remove the reinterpreted entries.
+                this.addedEvents.RemoveAt(iAdded);
+                this.removedEvents.RemoveAt(iRemoved);
+                break;
+            }
+        }
+
+        // Resolve changelog for item moved, from 2 changed events.
+        for (var i = this.changedEvents.Count - 1; i >= 0; --i)
+        {
+            var e1 = this.changedEvents[i];
+            for (var j = i - 1; j >= 0; --j)
             {
-                var added = this.addedEvents[iAdded];
+                var e2 = this.changedEvents[j];
-                for (var iRemoved = this.removedEvents.Count - 1; iRemoved >= 0; --iRemoved)
+                if (e1.Item.ItemId != e2.Item.ItemId || e1.Item.ItemId != e2.Item.ItemId)
-                {
+                    continue;
-                    var removed = this.removedEvents[iRemoved];
-                    if (added.Item.ItemId != removed.Item.ItemId)
-                        continue;
 
-                    this.movedEvents.Add(new(removed, added));
+                // move happened, and e2 has an item
-                        
+                if (!e2.Item.IsEmpty)
-                    // Remove the reinterpreted entries.
+                    this.movedEvents.Add(new(e1, e2));
-                    this.addedEvents.RemoveAt(iAdded);
+
-                    this.removedEvents.RemoveAt(iRemoved);
+                // move happened, and e1 has an item
-                    break;
+                if (!e1.Item.IsEmpty)
-                }
+                    this.movedEvents.Add(new(e2, e1));
+
+                // Remove the reinterpreted entries. Note that i > j.
+                this.changedEvents.RemoveAt(i);
+                this.changedEvents.RemoveAt(j);
+                break;
             }
+        }
 
-            // Resolve changelog for item moved, from 2 changed events.
+        // Log only if it matters.
-            for (var i = this.changedEvents.Count - 1; i >= 0; --i)
+        if (this.dalamudConfiguration.LogLevel <= LogEventLevel.Verbose)
-            {
+        {
-                var e1 = this.changedEvents[i];
-                for (var j = i - 1; j >= 0; --j)
-                {
-                    var e2 = this.changedEvents[j];
-                    if (e1.Item.ItemId != e2.Item.ItemId || e1.Item.ItemId != e2.Item.ItemId)
-                        continue;
-
-                    // move happened, and e2 has an item
-                    if (!e2.Item.IsEmpty)
-                        this.movedEvents.Add(new(e1, e2));
-
-                    // move happened, and e1 has an item
-                    if (!e1.Item.IsEmpty)
-                        this.movedEvents.Add(new(e2, e1));
-                        
-                    // Remove the reinterpreted entries. Note that i > j.
-                    this.changedEvents.RemoveAt(i);
-                    this.changedEvents.RemoveAt(j);
-                    break;
-                }
-            }
-
-            // Log only if it matters.
-            if (this.dalamudConfiguration.LogLevel >= LogEventLevel.Verbose)
-            {
-                foreach (var x in this.addedEvents)
-                    Log.Verbose($"{x}");
-            
-                foreach (var x in this.removedEvents)
-                    Log.Verbose($"{x}");
-            
-                foreach (var x in this.changedEvents)
-                    Log.Verbose($"{x}");
-            
-                foreach (var x in this.movedEvents)
-                    Log.Verbose($"{x} (({x.SourceEvent}) + ({x.TargetEvent}))");
-            }
-
-            // Broadcast InventoryChanged, if necessary.
-            if (this.InventoryChanged is not null)
-            {
-                this.allEvents.Clear();
-                this.allEvents.EnsureCapacity(
-                    this.addedEvents.Count
-                    + this.removedEvents.Count
-                    + this.changedEvents.Count
-                    + this.movedEvents.Count);
-                this.allEvents.AddRange(this.addedEvents);
-                this.allEvents.AddRange(this.removedEvents);
-                this.allEvents.AddRange(this.changedEvents);
-                this.allEvents.AddRange(this.movedEvents);
-                InvokeSafely(this.InventoryChanged, this.allEvents);
-            }
-
-            // Broadcast the rest.
             foreach (var x in this.addedEvents)
-                InvokeSafely(this.ItemAdded, x);
+                Log.Verbose($"{x}");
-            
+
             foreach (var x in this.removedEvents)
-                InvokeSafely(this.ItemRemoved, x);
+                Log.Verbose($"{x}");
-            
+
             foreach (var x in this.changedEvents)
-                InvokeSafely(this.ItemChanged, x);
+                Log.Verbose($"{x}");
-            
+
             foreach (var x in this.movedEvents)
-                InvokeSafely(this.ItemMoved, x);
+                Log.Verbose($"{x} (({x.SourceEvent}) + ({x.TargetEvent}))");
         }
-        finally
+
+        // Broadcast the rest.
+        InvokeSafely(
+            this.InventoryChanged,
+            new DeferredReadOnlyCollection<InventoryEventArgs>(
+                this.addedEvents.Count +
+                this.removedEvents.Count +
+                this.changedEvents.Count +
+                this.movedEvents.Count,
+                () => Array.Empty<InventoryEventArgs>()
+                           .Concat(this.addedEvents)
+                           .Concat(this.removedEvents)
+                           .Concat(this.changedEvents)
+                           .Concat(this.movedEvents)));
+
+        foreach (var x in this.addedEvents)
+            InvokeSafely(this.ItemAdded, x);
+
+        foreach (var x in this.removedEvents)
+            InvokeSafely(this.ItemRemoved, x);
+
+        foreach (var x in this.changedEvents)
+            InvokeSafely(this.ItemChanged, x);
+
+        foreach (var x in this.movedEvents)
+            InvokeSafely(this.ItemMoved, x);
+
+        // We're done using the lists. Clean them up.
+        this.addedEvents.Clear();
+        this.removedEvents.Clear();
+        this.changedEvents.Clear();
+        this.movedEvents.Clear();
+    }
+
+    /// <summary>
+    /// A <see cref="IReadOnlyCollection{T}"/> view of <see cref="IEnumerable{T}"/>, so that the number of items
+    /// contained within can be known in advance, and it can be enumerated multiple times.
+    /// </summary>
+    /// <typeparam name="T">The type of elements being enumerated.</typeparam>
+    private class DeferredReadOnlyCollection<T> : IReadOnlyCollection<T>
+    {
+        private readonly Func<IEnumerable<T>> enumerableGenerator;
+
+        public DeferredReadOnlyCollection(int count, Func<IEnumerable<T>> enumerableGenerator)
         {
-            this.addedEvents.Clear();
+            this.enumerableGenerator = enumerableGenerator;
-            this.removedEvents.Clear();
+            this.Count = count;
-            this.changedEvents.Clear();
-            this.movedEvents.Clear();
         }
+
+        public int Count { get; }
+
+        public IEnumerator<T> GetEnumerator() => this.enumerableGenerator().GetEnumerator();
+
+        IEnumerator IEnumerable.GetEnumerator() => this.enumerableGenerator().GetEnumerator();
     }
 }
 
@@ -313,10 +325,10 @@ internal class GameInventoryPluginScoped : IDisposable, IServiceType, IGameInven
     public event IGameInventory.InventoryChangedDelegate? ItemRemoved;
 
     /// <inheritdoc/>
-    public event IGameInventory.InventoryChangedDelegate? ItemMoved;
+    public event IGameInventory.InventoryChangedDelegate? ItemChanged;
 
     /// <inheritdoc/>
-    public event IGameInventory.InventoryChangedDelegate? ItemChanged;
+    public event IGameInventory.InventoryChangedDelegate? ItemMoved;
 
     /// <inheritdoc/>
     public void Dispose()
@@ -325,15 +337,15 @@ internal class GameInventoryPluginScoped : IDisposable, IServiceType, IGameInven
         this.gameInventoryService.InventoryChangedRaw -= this.OnInventoryChangedRawForward;
         this.gameInventoryService.ItemAdded -= this.OnInventoryItemAddedForward;
         this.gameInventoryService.ItemRemoved -= this.OnInventoryItemRemovedForward;
-        this.gameInventoryService.ItemMoved -= this.OnInventoryItemMovedForward;
         this.gameInventoryService.ItemChanged -= this.OnInventoryItemChangedForward;
-        
+        this.gameInventoryService.ItemMoved -= this.OnInventoryItemMovedForward;
+
         this.InventoryChanged = null;
         this.InventoryChangedRaw = null;
         this.ItemAdded = null;
         this.ItemRemoved = null;
-        this.ItemMoved = null;
         this.ItemChanged = null;
+        this.ItemMoved = null;
     }
 
     private void OnInventoryChangedForward(IReadOnlyCollection<InventoryEventArgs> events)
@@ -341,16 +353,16 @@ internal class GameInventoryPluginScoped : IDisposable, IServiceType, IGameInven
 
     private void OnInventoryChangedRawForward(IReadOnlyCollection<InventoryEventArgs> events)
         => this.InventoryChangedRaw?.Invoke(events);
-    
+
     private void OnInventoryItemAddedForward(GameInventoryEvent type, InventoryEventArgs data)
         => this.ItemAdded?.Invoke(type, data);
-    
+
     private void OnInventoryItemRemovedForward(GameInventoryEvent type, InventoryEventArgs data)
         => this.ItemRemoved?.Invoke(type, data);
 
-    private void OnInventoryItemMovedForward(GameInventoryEvent type, InventoryEventArgs data)
-        => this.ItemMoved?.Invoke(type, data);
-
     private void OnInventoryItemChangedForward(GameInventoryEvent type, InventoryEventArgs data)
         => this.ItemChanged?.Invoke(type, data);
+
+    private void OnInventoryItemMovedForward(GameInventoryEvent type, InventoryEventArgs data)
+        => this.ItemMoved?.Invoke(type, data);
 }

Dalamud/Game/Inventory/GameInventoryEvent.cs

@@ -3,7 +3,6 @@
 /// <summary>
 /// Class representing a item's changelog state.
 /// </summary>
-[Flags]
 public enum GameInventoryEvent
 {
     /// <summary>
@@ -11,24 +10,24 @@ public enum GameInventoryEvent
     /// You should not see this value, unless you explicitly used it yourself, or APIs using this enum say otherwise.
     /// </summary>
     Empty = 0,
-    
+
     /// <summary>
     /// Item was added to an inventory.
     /// </summary>
-    Added = 1 << 0,
+    Added = 1,
-    
+
     /// <summary>
     /// Item was removed from an inventory.
     /// </summary>
-    Removed = 1 << 1,
+    Removed = 2,
-    
+
     /// <summary>
     /// Properties are changed for an item in an inventory.
     /// </summary>
-    Changed = 1 << 2,
+    Changed = 3,
-    
+
     /// <summary>
     /// Item has been moved, possibly across different inventories.
     /// </summary>
-    Moved = 1 << 3,
+    Moved = 4,
 }

Dalamud/Game/Inventory/GameInventoryItem.cs

@@ -12,11 +12,6 @@ namespace Dalamud.Game.Inventory;
 [StructLayout(LayoutKind.Explicit, Size = StructSizeInBytes)]
 public unsafe struct GameInventoryItem : IEquatable<GameInventoryItem>
 {
-    /// <summary>
-    /// An empty instance of <see cref="GameInventoryItem"/>.
-    /// </summary>
-    internal static readonly GameInventoryItem Empty = default;
-
     /// <summary>
     /// The actual data.
     /// </summary>
@@ -104,7 +99,7 @@ public unsafe struct GameInventoryItem : IEquatable<GameInventoryItem>
     /// Gets the array of materia types.
     /// </summary>
     public ReadOnlySpan<ushort> Materia => new(Unsafe.AsPointer(ref Unsafe.AsRef(in this.InternalItem.Materia[0])), 5);
-    
+
     /// <summary>
     /// Gets the array of materia grades.
     /// </summary>
@@ -119,8 +114,8 @@ public unsafe struct GameInventoryItem : IEquatable<GameInventoryItem>
     /// <summary>
     /// Gets the glamour id for this item.
     /// </summary>
-    public uint GlmaourId => this.InternalItem.GlamourID;
+    public uint GlamourId => this.InternalItem.GlamourID;
-    
+
     /// <summary>
     /// Gets the items crafter's content id.
     /// NOTE: I'm not sure if this is a good idea to include or not in the dalamud api. Marked internal for now.
@@ -163,6 +158,6 @@ public unsafe struct GameInventoryItem : IEquatable<GameInventoryItem>
     /// <inheritdoc cref="object.ToString"/>
     public override string ToString() =>
         this.IsEmpty
-            ? "<Empty>"
+            ? "no item"
-            : $"Item #{this.ItemId} at slot {this.InventorySlot} in {this.ContainerType}";
+            : $"item #{this.ItemId} at slot {this.InventorySlot} in {this.ContainerType}";
 }

Dalamud/Game/Inventory/GameInventoryType.cs

@@ -9,17 +9,17 @@ public enum GameInventoryType : ushort
     /// First panel of main player inventory.
     /// </summary>
     Inventory1 = 0,
-    
+
     /// <summary>
     /// Second panel of main player inventory.
     /// </summary>
     Inventory2 = 1,
-    
+
     /// <summary>
     /// Third panel of main player inventory.
     /// </summary>
     Inventory3 = 2,
-    
+
     /// <summary>
     /// Fourth panel of main player inventory.
     /// </summary>
@@ -40,32 +40,32 @@ public enum GameInventoryType : ushort
     /// Crystal container.
     /// </summary>
     Crystals = 2001,
-    
+
     /// <summary>
     /// Mail container.
     /// </summary>
     Mail = 2003,
-    
+
     /// <summary>
     /// Key item container.
     /// </summary>
     KeyItems = 2004,
-    
+
     /// <summary>
     /// Quest item hand-in inventory.
     /// </summary>
     HandIn = 2005,
-    
+
     /// <summary>
     /// DamagedGear container.
     /// </summary>
     DamagedGear = 2007,
-    
+
     /// <summary>
     /// Examine window container.
     /// </summary>
     Examine = 2009,
-    
+
     /// <summary>
     /// Doman Enclave Reconstruction Reclamation Box.
     /// </summary>
@@ -75,22 +75,22 @@ public enum GameInventoryType : ushort
     /// Armory off-hand weapon container.
     /// </summary>
     ArmoryOffHand = 3200,
-    
+
     /// <summary>
     /// Armory head container.
     /// </summary>  
     ArmoryHead = 3201,
-       
+
     /// <summary>
     /// Armory body container.
     /// </summary>   
     ArmoryBody = 3202,
-        
+
     /// <summary>
     /// Armory hand/gloves container.
     /// </summary>  
     ArmoryHands = 3203,
-        
+
     /// <summary>
     /// Armory waist container.
     /// <remarks>
@@ -98,42 +98,42 @@ public enum GameInventoryType : ushort
     /// </remarks>
     /// </summary>  
     ArmoryWaist = 3204,
-        
+
     /// <summary>
     /// Armory legs/pants/skirt container.
     /// </summary>  
     ArmoryLegs = 3205,
-        
+
     /// <summary>
     /// Armory feet/boots/shoes container.
     /// </summary>  
     ArmoryFeets = 3206,
-        
+
     /// <summary>
     /// Armory earring container.
     /// </summary>  
     ArmoryEar = 3207,
-        
+
     /// <summary>
     /// Armory necklace container.
     /// </summary>  
     ArmoryNeck = 3208,
-        
+
     /// <summary>
     /// Armory bracelet container.
     /// </summary>  
     ArmoryWrist = 3209,
-        
+
     /// <summary>
     /// Armory ring container.
     /// </summary>  
     ArmoryRings = 3300,
-        
+
     /// <summary>
     /// Armory soul crystal container.
     /// </summary>  
     ArmorySoulCrystal = 3400,
-        
+
     /// <summary>
     /// Armory main-hand weapon container.
     /// </summary>  
@@ -143,17 +143,17 @@ public enum GameInventoryType : ushort
     /// First panel of saddelbag inventory.
     /// </summary>
     SaddleBag1 = 4000,
-    
+
     /// <summary>
     /// Second panel of Saddlebag inventory.
     /// </summary>
     SaddleBag2 = 4001,
-    
+
     /// <summary>
     /// First panel of premium saddlebag inventory.
     /// </summary>
     PremiumSaddleBag1 = 4100,
-    
+
     /// <summary>
     /// Second panel of premium saddlebag inventory.
     /// </summary>
@@ -163,52 +163,52 @@ public enum GameInventoryType : ushort
     /// First panel of retainer inventory.
     /// </summary>
     RetainerPage1 = 10000,
-    
+
     /// <summary>
     /// Second panel of retainer inventory.
     /// </summary>
     RetainerPage2 = 10001,
-    
+
     /// <summary>
     /// Third panel of retainer inventory.
     /// </summary>
     RetainerPage3 = 10002,
-    
+
     /// <summary>
     /// Fourth panel of retainer inventory.
     /// </summary>
     RetainerPage4 = 10003,
-    
+
     /// <summary>
     /// Fifth panel of retainer inventory.
     /// </summary>
     RetainerPage5 = 10004,
-    
+
     /// <summary>
     /// Sixth panel of retainer inventory.
     /// </summary>
     RetainerPage6 = 10005,
-    
+
     /// <summary>
     /// Seventh panel of retainer inventory.
     /// </summary>
     RetainerPage7 = 10006,
-    
+
     /// <summary>
     /// Retainer equipment container.
     /// </summary>
     RetainerEquippedItems = 11000,
-    
+
     /// <summary>
     /// Retainer currency container.
     /// </summary>
     RetainerGil = 12000,
-    
+
     /// <summary>
     /// Retainer crystal container.
     /// </summary>
     RetainerCrystals = 12001,
-    
+
     /// <summary>
     /// Retainer market item container.
     /// </summary>
@@ -218,32 +218,32 @@ public enum GameInventoryType : ushort
     /// First panel of Free Company inventory.
     /// </summary>
     FreeCompanyPage1 = 20000,
-    
+
     /// <summary>
     /// Second panel of Free Company inventory.
     /// </summary>
     FreeCompanyPage2 = 20001,
-    
+
     /// <summary>
     /// Third panel of Free Company inventory.
     /// </summary>
     FreeCompanyPage3 = 20002,
-    
+
     /// <summary>
     /// Fourth panel of Free Company inventory.
     /// </summary>
     FreeCompanyPage4 = 20003,
-    
+
     /// <summary>
     /// Fifth panel of Free Company inventory.
     /// </summary>
     FreeCompanyPage5 = 20004,
-    
+
     /// <summary>
     /// Free Company currency container.
     /// </summary>
     FreeCompanyGil = 22000,
-    
+
     /// <summary>
     /// Free Company crystal container.
     /// </summary>
@@ -253,102 +253,102 @@ public enum GameInventoryType : ushort
     /// Housing exterior appearance container.
     /// </summary>
     HousingExteriorAppearance = 25000,
-    
+
     /// <summary>
     /// Housing exterior placed items container.
     /// </summary>
     HousingExteriorPlacedItems = 25001,
-    
+
     /// <summary>
     /// Housing interior appearance container.
     /// </summary>
     HousingInteriorAppearance = 25002,
-    
+
     /// <summary>
     /// First panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems1 = 25003,
-    
+
     /// <summary>
     /// Second panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems2 = 25004,
-    
+
     /// <summary>
     /// Third panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems3 = 25005,
-        
+
     /// <summary>
     /// Fourth panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems4 = 25006,
-        
+
     /// <summary>
     /// Fifth panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems5 = 25007,
-        
+
     /// <summary>
     /// Sixth panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems6 = 25008,
-        
+
     /// <summary>
     /// Seventh panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems7 = 25009,
-        
+
     /// <summary>
     /// Eighth panel of housing interior inventory.
     /// </summary>
     HousingInteriorPlacedItems8 = 25010,
-        
+
     /// <summary>
     /// Housing exterior storeroom inventory.
     /// </summary>
     HousingExteriorStoreroom = 27000,
-            
+
     /// <summary>
     /// First panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom1 = 27001,
-                
+
     /// <summary>
     /// Second panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom2 = 27002,
-                
+
     /// <summary>
     /// Third panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom3 = 27003,
-                
+
     /// <summary>
     /// Fourth panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom4 = 27004,
-                
+
     /// <summary>
     /// Fifth panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom5 = 27005,
-                
+
     /// <summary>
     /// Sixth panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom6 = 27006,
-                
+
     /// <summary>
     /// Seventh panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom7 = 27007,
-                
+
     /// <summary>
     /// Eighth panel of housing interior storeroom inventory.
     /// </summary>
     HousingInteriorStoreroom8 = 27008,
-    
+
     /// <summary>
     /// An invalid value.
     /// </summary>

Dalamud/Game/Inventory/InventoryChangeArgsTypes/InventoryEventArgs.cs

@@ -1,13 +1,12 @@
-using System.Diagnostics.CodeAnalysis;
+namespace Dalamud.Game.Inventory.InventoryChangeArgsTypes;
-
-namespace Dalamud.Game.Inventory.InventoryChangeArgsTypes;
 
 /// <summary>
 /// Abstract base class representing inventory changed events.
 /// </summary>
-[SuppressMessage("StyleCop.CSharp.OrderingRules", "SA1206:Declaration keywords should follow order", Justification = "It literally says <access modifiers>, <static>, and then <all other keywords>. required is not an access modifier.")]
 public abstract class InventoryEventArgs
 {
+    private readonly GameInventoryItem item;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="InventoryEventArgs"/> class.
     /// </summary>
@@ -16,7 +15,7 @@ public abstract class InventoryEventArgs
     protected InventoryEventArgs(GameInventoryEvent type, in GameInventoryItem item)
     {
         this.Type = type;
-        this.Item = item;
+        this.item = item;
     }
 
     /// <summary>
@@ -28,8 +27,11 @@ public abstract class InventoryEventArgs
     /// Gets the item associated with this event.
     /// <remarks><em>This is a copy of the item data.</em></remarks>
     /// </summary>
-    public GameInventoryItem Item { get; }
+    // impl note: we return a ref readonly view, to avoid making copies every time this property is accessed.
-    
+    // see: https://devblogs.microsoft.com/premier-developer/avoiding-struct-and-readonly-reference-performance-pitfalls-with-errorprone-net/
+    // "Consider using ref readonly locals and ref return for library code"
+    public ref readonly GameInventoryItem Item => ref this.item;
+
     /// <inheritdoc/>
     public override string ToString() => $"<{this.Type}> ({this.Item})";
 }

Dalamud/Game/Inventory/InventoryChangeArgsTypes/InventoryItemChangedArgs.cs

@@ -6,6 +6,8 @@
 /// </summary>
 public class InventoryItemChangedArgs : InventoryEventArgs
 {
+    private readonly GameInventoryItem oldItemState;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="InventoryItemChangedArgs"/> class.
     /// </summary>
@@ -14,7 +16,7 @@ public class InventoryItemChangedArgs : InventoryEventArgs
     internal InventoryItemChangedArgs(in GameInventoryItem oldItem, in GameInventoryItem newItem)
         : base(GameInventoryEvent.Changed, newItem)
     {
-        this.OldItemState = oldItem;
+        this.oldItemState = oldItem;
     }
 
     /// <summary>
@@ -29,6 +31,8 @@ public class InventoryItemChangedArgs : InventoryEventArgs
 
     /// <summary>
     /// Gets the state of the item from before it was changed.
+    /// <remarks><em>This is a copy of the item data.</em></remarks>
     /// </summary>
-    public GameInventoryItem OldItemState { get; init; }
+    // impl note: see InventoryEventArgs.Item.
+    public ref readonly GameInventoryItem OldItemState => ref this.oldItemState;
 }

Dalamud/Game/Inventory/InventoryChangeArgsTypes/InventoryItemMovedArgs.cs

@@ -1,11 +1,8 @@
-using System.Diagnostics.CodeAnalysis;
+namespace Dalamud.Game.Inventory.InventoryChangeArgsTypes;
-
-namespace Dalamud.Game.Inventory.InventoryChangeArgsTypes;
 
 /// <summary>
 /// Represents the data associated with an item being moved from one inventory and added to another.
 /// </summary>
-[SuppressMessage("StyleCop.CSharp.OrderingRules", "SA1206:Declaration keywords should follow order", Justification = "It literally says <access modifiers>, <static>, and then <all other keywords>. required is not an access modifier.")]
 public class InventoryItemMovedArgs : InventoryEventArgs
 {
     /// <summary>
@@ -29,7 +26,7 @@ public class InventoryItemMovedArgs : InventoryEventArgs
     /// Gets the inventory this item was moved to.
     /// </summary>
     public GameInventoryType TargetInventory => this.Item.ContainerType;
-    
+
     /// <summary>
     /// Gets the slot this item was moved from.
     /// </summary>
@@ -49,7 +46,7 @@ public class InventoryItemMovedArgs : InventoryEventArgs
     /// Gets the associated target event.
     /// </summary>
     internal InventoryEventArgs TargetEvent { get; }
-    
+
     /// <inheritdoc/>
     public override string ToString() =>
         $"<{this.Type}> (Item #{this.Item.ItemId}) from (slot {this.SourceSlot} in {this.SourceInventory}) to (slot {this.TargetSlot} in {this.TargetInventory})";

Dalamud/Game/Inventory/InventoryChangeArgsTypes/InventoryItemRemovedArgs.cs

@@ -13,12 +13,12 @@ public class InventoryItemRemovedArgs : InventoryEventArgs
         : base(GameInventoryEvent.Removed, item)
     {
     }
-    
+
     /// <summary>
     /// Gets the inventory this item was removed from.
     /// </summary>
     public GameInventoryType Inventory => this.Item.ContainerType;
-    
+
     /// <summary>
     /// Gets the slot this item was removed from.
     /// </summary>

Dalamud/Plugin/Services/IGameInventory.cs

@@ -24,12 +24,12 @@ public interface IGameInventory
     /// <param name="type">The event try that triggered this message.</param>
     /// <param name="data">Data for the triggered event.</param>
     public delegate void InventoryChangedDelegate(GameInventoryEvent type, InventoryEventArgs data);
-    
+
     /// <summary>
     /// Event that is fired when the inventory has been changed.
     /// </summary>
     public event InventoryChangelogDelegate InventoryChanged;
-    
+
     /// <summary>
     /// Event that is fired when the inventory has been changed, without trying to interpret two inventory slot changes
     /// as a move event as appropriate.<br />