1 files changed, 88 insertions, 0 deletions
diff --git a/src/SMAPI/Framework/ModLoading/Rewriters/MethodParentRewriter.cs b/src/SMAPI/Framework/ModLoading/Rewriters/MethodParentRewriter.cs
new file mode 100644
index 00000000..974fcf4c
--- /dev/null
+++ b/src/SMAPI/Framework/ModLoading/Rewriters/MethodParentRewriter.cs
@@ -0,0 +1,88 @@
+using System;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+
+namespace StardewModdingAPI.Framework.ModLoading.Rewriters
+{
+    /// <summary>Rewrites method references from one parent type to another if the signatures match.</summary>
+    internal class MethodParentRewriter : IInstructionHandler
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The type whose methods to remap.</summary>
+        private readonly Type FromType;
+
+        /// <summary>The type with methods to map to.</summary>
+        private readonly Type ToType;
+
+        /// <summary>Whether to only rewrite references if loading the assembly on a different platform than it was compiled on.</summary>
+        private readonly bool OnlyIfPlatformChanged;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>A brief noun phrase indicating what the instruction finder matches.</summary>
+        public string NounPhrase { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="fromType">The type whose methods to remap.</param>
+        /// <param name="toType">The type with methods to map to.</param>
+        /// <param name="onlyIfPlatformChanged">Whether to only rewrite references if loading the assembly on a different platform than it was compiled on.</param>
+        public MethodParentRewriter(Type fromType, Type toType, bool onlyIfPlatformChanged = false)
+        {
+            this.FromType = fromType;
+            this.ToType = toType;
+            this.NounPhrase = $"{fromType.Name} methods";
+            this.OnlyIfPlatformChanged = onlyIfPlatformChanged;
+        }
+
+        /// <summary>Perform the predefined logic for a method if applicable.</summary>
+        /// <param name="module">The assembly module containing the instruction.</param>
+        /// <param name="method">The method definition containing the instruction.</param>
+        /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param>
+        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
+        public InstructionHandleResult Handle(ModuleDefinition module, MethodDefinition method, PlatformAssemblyMap assemblyMap, bool platformChanged)
+        {
+            return InstructionHandleResult.None;
+        }
+
+        /// <summary>Perform the predefined logic for an instruction if applicable.</summary>
+        /// <param name="module">The assembly module containing the instruction.</param>
+        /// <param name="cil">The CIL processor.</param>
+        /// <param name="instruction">The instruction to handle.</param>
+        /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param>
+        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
+        public InstructionHandleResult Handle(ModuleDefinition module, ILProcessor cil, Instruction instruction, PlatformAssemblyMap assemblyMap, bool platformChanged)
+        {
+            if (!this.IsMatch(instruction, platformChanged))
+                return InstructionHandleResult.None;
+
+            MethodReference methodRef = (MethodReference)instruction.Operand;
+            methodRef.DeclaringType = module.Import(this.ToType);
+            return InstructionHandleResult.Rewritten;
+        }
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Get whether a CIL instruction matches.</summary>
+        /// <param name="instruction">The IL instruction.</param>
+        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
+        protected bool IsMatch(Instruction instruction, bool platformChanged)
+        {
+            MethodReference methodRef = RewriteHelper.AsMethodReference(instruction);
+            return
+                methodRef != null
+                && (platformChanged || !this.OnlyIfPlatformChanged)
+                && methodRef.DeclaringType.FullName == this.FromType.FullName
+                && RewriteHelper.HasMatchingSignature(this.ToType, methodRef);
+        }
+    }
+}