1 files changed, 111 insertions, 0 deletions
diff --git a/src/StardewModdingAPI/Framework/Content/ContentEventData.cs b/src/StardewModdingAPI/Framework/Content/ContentEventData.cs
new file mode 100644
index 00000000..1a1779d4
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/Content/ContentEventData.cs
@@ -0,0 +1,111 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace StardewModdingAPI.Framework.Content
+{
+    /// <summary>Base implementation for a content helper which encapsulates access and changes to content being read from a data file.</summary>
+    /// <typeparam name="TValue">The interface value type.</typeparam>
+    internal class ContentEventData<TValue> : EventArgs, IContentEventData<TValue>
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>Normalises an asset key to match the cache key.</summary>
+        protected readonly Func<string, string> GetNormalisedPath;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The content's locale code, if the content is localised.</summary>
+        public string Locale { get; }
+
+        /// <summary>The normalised asset name being read. The format may change between platforms; see <see cref="IsAssetName"/> to compare with a known path.</summary>
+        public string AssetName { get; }
+
+        /// <summary>The content data being read.</summary>
+        public TValue Data { get; protected set; }
+
+        /// <summary>The content data type.</summary>
+        public Type DataType { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="locale">The content's locale code, if the content is localised.</param>
+        /// <param name="assetName">The normalised asset name being read.</param>
+        /// <param name="data">The content data being read.</param>
+        /// <param name="getNormalisedPath">Normalises an asset key to match the cache key.</param>
+        public ContentEventData(string locale, string assetName, TValue data, Func<string, string> getNormalisedPath)
+            : this(locale, assetName, data, data.GetType(), getNormalisedPath) { }
+
+        /// <summary>Construct an instance.</summary>
+        /// <param name="locale">The content's locale code, if the content is localised.</param>
+        /// <param name="assetName">The normalised asset name being read.</param>
+        /// <param name="data">The content data being read.</param>
+        /// <param name="dataType">The content data type being read.</param>
+        /// <param name="getNormalisedPath">Normalises an asset key to match the cache key.</param>
+        public ContentEventData(string locale, string assetName, TValue data, Type dataType, Func<string, string> getNormalisedPath)
+        {
+            this.Locale = locale;
+            this.AssetName = assetName;
+            this.Data = data;
+            this.DataType = dataType;
+            this.GetNormalisedPath = getNormalisedPath;
+        }
+
+        /// <summary>Get whether the asset name being loaded matches a given name after normalisation.</summary>
+        /// <param name="path">The expected asset path, relative to the game's content folder and without the .xnb extension or locale suffix (like 'Data\ObjectInformation').</param>
+        public bool IsAssetName(string path)
+        {
+            path = this.GetNormalisedPath(path);
+            return this.AssetName.Equals(path, StringComparison.InvariantCultureIgnoreCase);
+        }
+
+        /// <summary>Replace the entire content value with the given value. This is generally not recommended, since it may break compatibility with other mods or different versions of the game.</summary>
+        /// <param name="value">The new content value.</param>
+        /// <exception cref="ArgumentNullException">The <paramref name="value"/> is null.</exception>
+        /// <exception cref="InvalidCastException">The <paramref name="value"/>'s type is not compatible with the loaded asset's type.</exception>
+        public void ReplaceWith(TValue value)
+        {
+            if (value == null)
+                throw new ArgumentNullException(nameof(value), "Can't set a loaded asset to a null value.");
+            if (!this.DataType.IsInstanceOfType(value))
+                throw new InvalidCastException($"Can't replace loaded asset of type {this.GetFriendlyTypeName(this.DataType)} with value of type {this.GetFriendlyTypeName(value.GetType())}. The new type must be compatible to prevent game errors.");
+
+            this.Data = value;
+        }
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Get a human-readable type name.</summary>
+        /// <param name="type">The type to name.</param>
+        protected string GetFriendlyTypeName(Type type)
+        {
+            // dictionary
+            if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Dictionary<,>))
+            {
+                Type[] genericArgs = type.GetGenericArguments();
+                return $"Dictionary<{this.GetFriendlyTypeName(genericArgs[0])}, {this.GetFriendlyTypeName(genericArgs[1])}>";
+            }
+
+            // texture
+            if (type == typeof(Texture2D))
+                return type.Name;
+
+            // native type
+            if (type == typeof(int))
+                return "int";
+            if (type == typeof(string))
+                return "string";
+
+            // default
+            return type.FullName;
+        }
+    }
+}