add support for getting a patch helper for arbitrary data

docs/release-notes.md

@@ -17,6 +17,7 @@
 
 * For modders:
   * Added map patching to the content API (via `asset.AsMap()`).
+  * Added support for using patch helpers (e.g. for image/map patching) with arbitrary data (via `helper.Content.GetPatchHelper`).
   * Added `SDate` fields/methods: `SeasonIndex`, `FromDaysSinceStart`, `FromWorldDate`, `ToWorldDate`, and `ToLocaleString` (thanks to kdau!).
   * Added `SDate` translations taken from the Lookup Anything mod.¹
   * Fixed asset propagation on Linux/Mac for monster sprites, NPC dialogue, and NPC schedules.

src/SMAPI/Framework/ModHelpers/ContentHelper.cs

@@ -7,6 +7,7 @@ using System.IO;
 using System.Linq;
 using Microsoft.Xna.Framework.Content;
 using Microsoft.Xna.Framework.Graphics;
+using StardewModdingAPI.Framework.Content;
 using StardewModdingAPI.Framework.ContentManagers;
 using StardewModdingAPI.Framework.Exceptions;
 using StardewValley;
@@ -164,6 +165,19 @@ namespace StardewModdingAPI.Framework.ModHelpers
             return this.ContentCore.InvalidateCache(predicate).Any();
         }
 
+        /// <summary>Get a patch helper for arbitrary data.</summary>
+        /// <typeparam name="T">The data type.</typeparam>
+        /// <param name="data">The asset data.</param>
+        /// <param name="assetName">The asset name. This is only used for tracking purposes and has no effect on the patch helper.</param>
+        public IAssetData GetPatchHelper<T>(T data, string assetName = null)
+        {
+            if (data == null)
+                throw new ArgumentNullException(nameof(data), "Can't get a patch helper for a null value.");
+
+            assetName ??= $"temp/{Guid.NewGuid():N}";
+            return new AssetDataForObject(this.CurrentLocale, assetName, data, this.NormalizeAssetName);
+        }
+
 
         /*********
         ** Private methods

src/SMAPI/IContentHelper.cs

@@ -64,5 +64,11 @@ namespace StardewModdingAPI
         /// <param name="predicate">A predicate matching the assets to invalidate.</param>
         /// <returns>Returns whether any cache entries were invalidated.</returns>
         bool InvalidateCache(Func<IAssetInfo, bool> predicate);
+
+        /// <summary>Get a patch helper for arbitrary data.</summary>
+        /// <typeparam name="T">The data type.</typeparam>
+        /// <param name="data">The asset data.</param>
+        /// <param name="assetName">The asset name. This is only used for tracking purposes and has no effect on the patch helper.</param>
+        IAssetData GetPatchHelper<T>(T data, string assetName = null);
     }
 }