Merge branch 'develop' into stable

1 files changed, 66 insertions, 0 deletions

diff --git a/src/SMAPI/Framework/SnapshotItemListDiff.cs b/src/SMAPI/Framework/SnapshotItemListDiff.cs
new file mode 100644
index 00000000..e8ab1b1e
--- /dev/null
+++ b/src/SMAPI/Framework/SnapshotItemListDiff.cs
@@ -0,0 +1,66 @@
+using System.Collections.Generic;
+using System.Linq;
+using StardewModdingAPI.Events;
+using StardewValley;
+
+namespace StardewModdingAPI.Framework
+{
+    /// <summary>A snapshot of a tracked item list.</summary>
+    internal class SnapshotItemListDiff
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>Whether the item list changed.</summary>
+        public bool IsChanged { get; }
+
+        /// <summary>The removed values.</summary>
+        public Item[] Removed { get; }
+
+        /// <summary>The added values.</summary>
+        public Item[] Added { get; }
+
+        /// <summary>The items whose stack sizes changed.</summary>
+        public ItemStackSizeChange[] QuantityChanged { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Update the snapshot.</summary>
+        /// <param name="added">The added values.</param>
+        /// <param name="removed">The removed values.</param>
+        /// <param name="sizesChanged">The items whose stack sizes changed.</param>
+        public SnapshotItemListDiff(Item[] added, Item[] removed, ItemStackSizeChange[] sizesChanged)
+        {
+            this.Removed = removed;
+            this.Added = added;
+            this.QuantityChanged = sizesChanged;
+
+            this.IsChanged = removed.Length > 0 || added.Length > 0 || sizesChanged.Length > 0;
+        }
+
+        /// <summary>Get a snapshot diff if anything changed in the given data.</summary>
+        /// <param name="added">The added item stacks.</param>
+        /// <param name="removed">The removed item stacks.</param>
+        /// <param name="stackSizes">The items with their previous stack sizes.</param>
+        /// <param name="changes">The inventory changes, or <c>null</c> if nothing changed.</param>
+        /// <returns>Returns whether anything changed.</returns>
+        public static bool TryGetChanges(ISet<Item> added, ISet<Item> removed, IDictionary<Item, int> stackSizes, out SnapshotItemListDiff changes)
+        {
+            KeyValuePair<Item, int>[] sizesChanged = stackSizes.Where(p => p.Key.Stack != p.Value).ToArray();
+            if (sizesChanged.Any() || added.Any() || removed.Any())
+            {
+                changes = new SnapshotItemListDiff(
+                    added: added.ToArray(),
+                    removed: removed.ToArray(),
+                    sizesChanged: sizesChanged.Select(p => new ItemStackSizeChange(p.Key, p.Value, p.Key.Stack)).ToArray()
+                );
+                return true;
+            }
+
+            changes = null;
+            return false;
+        }
+    }
+}