rewrite SpriteBatch.Begin calls for compatibility (#166)

5 files changed, 182 insertions, 1 deletions

diff --git a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/BaseMethodRewriter.cs b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/BaseMethodRewriter.cs
new file mode 100644
index 00000000..1af6e6c4
--- /dev/null
+++ b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/BaseMethodRewriter.cs
@@ -0,0 +1,92 @@
+using System;
+using System.Linq;
+using System.Reflection;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+
+namespace StardewModdingAPI.AssemblyRewriters.Rewriters
+{
+    /// <summary>Base class for a method rewriter.</summary>
+    public abstract class BaseMethodRewriter : IMethodRewriter
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Get whether the given method reference can be rewritten.</summary>
+        /// <param name="methodRef">The method reference.</param>
+        public abstract bool ShouldRewrite(MethodReference methodRef);
+
+        /// <summary>Rewrite a method for compatibility.</summary>
+        /// <param name="module">The module being rewritten.</param>
+        /// <param name="cil">The CIL rewriter.</param>
+        /// <param name="callOp">The instruction which calls the method.</param>
+        /// <param name="methodRef">The method reference invoked by the <paramref name="callOp"/>.</param>
+        /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param>
+        public abstract void Rewrite(ModuleDefinition module, ILProcessor cil, Instruction callOp, MethodReference methodRef, PlatformAssemblyMap assemblyMap);
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Get whether a method definition matches the signature expected by a method reference.</summary>
+        /// <param name="definition">The method definition.</param>
+        /// <param name="reference">The method reference.</param>
+        protected bool HasMatchingSignature(MethodInfo definition, MethodReference reference)
+        {
+            // same name
+            if (definition.Name != reference.Name)
+                return false;
+
+            // same arguments
+            ParameterInfo[] definitionParameters = definition.GetParameters();
+            ParameterDefinition[] referenceParameters = reference.Parameters.ToArray();
+            if (referenceParameters.Length != definitionParameters.Length)
+                return false;
+            for (int i = 0; i < referenceParameters.Length; i++)
+            {
+                if (!this.IsMatchingType(definitionParameters[i].ParameterType, referenceParameters[i].ParameterType))
+                    return false;
+            }
+            return true;
+        }
+
+        /// <summary>Get whether a type has a method whose signature matches the one expected by a method reference.</summary>
+        /// <param name="type">The type to check.</param>
+        /// <param name="reference">The method reference.</param>
+        protected bool HasMatchingSignature(Type type, MethodReference reference)
+        {
+            return type
+                .GetMethods(BindingFlags.Instance | BindingFlags.DeclaredOnly | BindingFlags.Public)
+                .Any(method => this.HasMatchingSignature(method, reference));
+        }
+
+        /// <summary>Get whether a type matches a type reference.</summary>
+        /// <param name="type">The defined type.</param>
+        /// <param name="reference">The type reference.</param>
+        private bool IsMatchingType(Type type, TypeReference reference)
+        {
+            // same namespace & name
+            if (type.Namespace != reference.Namespace || type.Name != reference.Name)
+                return false;
+
+            // same generic parameters
+            if (type.IsGenericType)
+            {
+                if (!reference.IsGenericInstance)
+                    return false;
+
+                Type[] defGenerics = type.GetGenericArguments();
+                TypeReference[] refGenerics = ((GenericInstanceType)reference).GenericArguments.ToArray();
+                if (defGenerics.Length != refGenerics.Length)
+                    return false;
+                for (int i = 0; i < defGenerics.Length; i++)
+                {
+                    if (!this.IsMatchingType(defGenerics[i], refGenerics[i]))
+                        return false;
+                }
+            }
+
+            return true;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/SpriteBatchRewriter.cs b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/SpriteBatchRewriter.cs
new file mode 100644
index 00000000..1c0a5cf3
--- /dev/null
+++ b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/SpriteBatchRewriter.cs
@@ -0,0 +1,30 @@
+using Microsoft.Xna.Framework.Graphics;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+using StardewModdingAPI.AssemblyRewriters.Wrappers;
+
+namespace StardewModdingAPI.AssemblyRewriters.Rewriters
+{
+    /// <summary>Rewrites references to <see cref="SpriteBatch"/> to fix inconsistent method signatures between MonoGame and XNA.</summary>
+    /// <remarks>MonoGame has one <c>SpriteBatch.Begin</c> method with optional arguments, but XNA has multiple method overloads. Incompatible method references are rewritten to use <see cref="CompatibleSpriteBatch"/>, which redirects all method signatures to the proper compiled MonoGame/XNA method.</remarks>
+    public class SpriteBatchRewriter : BaseMethodRewriter
+    {
+        /// <summary>Get whether the given method reference can be rewritten.</summary>
+        /// <param name="methodRef">The method reference.</param>
+        public override bool ShouldRewrite(MethodReference methodRef)
+        {
+            return methodRef.DeclaringType.FullName == typeof(SpriteBatch).FullName && this.HasMatchingSignature(typeof(CompatibleSpriteBatch), methodRef);
+        }
+
+        /// <summary>Rewrite a method for compatibility.</summary>
+        /// <param name="module">The module being rewritten.</param>
+        /// <param name="cil">The CIL rewriter.</param>
+        /// <param name="callOp">The instruction which calls the method.</param>
+        /// <param name="methodRef">The method reference invoked by the <paramref name="callOp"/>.</param>
+        /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param>
+        public override void Rewrite(ModuleDefinition module, ILProcessor cil, Instruction callOp, MethodReference methodRef, PlatformAssemblyMap assemblyMap)
+        {
+            methodRef.DeclaringType = module.Import(typeof(CompatibleSpriteBatch));
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/StardewModdingAPI.AssemblyRewriters/StardewModdingAPI.AssemblyRewriters.csproj b/src/StardewModdingAPI.AssemblyRewriters/StardewModdingAPI.AssemblyRewriters.csproj
index b2533566..51a49da0 100644
--- a/src/StardewModdingAPI.AssemblyRewriters/StardewModdingAPI.AssemblyRewriters.csproj
+++ b/src/StardewModdingAPI.AssemblyRewriters/StardewModdingAPI.AssemblyRewriters.csproj
@@ -75,6 +75,9 @@
     <Compile Include="Platform.cs" />
     <Compile Include="PlatformAssemblyMap.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Rewriters\BaseMethodRewriter.cs" />
+    <Compile Include="Rewriters\SpriteBatchRewriter.cs" />
+    <Compile Include="Wrappers\CompatibleSpriteBatch.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="packages.config" />
diff --git a/src/StardewModdingAPI.AssemblyRewriters/Wrappers/CompatibleSpriteBatch.cs b/src/StardewModdingAPI.AssemblyRewriters/Wrappers/CompatibleSpriteBatch.cs
new file mode 100644
index 00000000..e28d1a68
--- /dev/null
+++ b/src/StardewModdingAPI.AssemblyRewriters/Wrappers/CompatibleSpriteBatch.cs
@@ -0,0 +1,52 @@
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+
+#pragma warning disable CS0109 // Member does not hide an inherited member; new keyword is not required
+namespace StardewModdingAPI.AssemblyRewriters.Wrappers
+{
+    /// <summary>Wraps <see cref="SpriteBatch"/> methods that are incompatible when converting compiled code between MonoGame and XNA.</summary>
+    public class CompatibleSpriteBatch : SpriteBatch
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        public CompatibleSpriteBatch(GraphicsDevice graphicsDevice) : base(graphicsDevice) { }
+
+        /****
+        ** MonoGame signatures
+        ****/
+        public new void Begin(SpriteSortMode sortMode, BlendState blendState, SamplerState samplerState, DepthStencilState depthStencilState, RasterizerState rasterizerState, Effect effect, Matrix? matrix)
+        {
+            base.Begin(sortMode, blendState, samplerState, depthStencilState, rasterizerState, effect, matrix ?? Matrix.Identity);
+        }
+
+        /****
+        ** XNA signatures
+        ****/
+        public new void Begin()
+        {
+            base.Begin();
+        }
+
+        public new void Begin(SpriteSortMode sortMode, BlendState blendState)
+        {
+            base.Begin(sortMode, blendState);
+        }
+
+        public new void Begin(SpriteSortMode sortMode, BlendState blendState, SamplerState samplerState, DepthStencilState depthStencilState, RasterizerState rasterizerState)
+        {
+            base.Begin(sortMode, blendState, samplerState, depthStencilState, rasterizerState);
+        }
+
+        public new void Begin(SpriteSortMode sortMode, BlendState blendState, SamplerState samplerState, DepthStencilState depthStencilState, RasterizerState rasterizerState, Effect effect)
+        {
+            base.Begin(sortMode, blendState, samplerState, depthStencilState, rasterizerState, effect);
+        }
+
+        public new void Begin(SpriteSortMode sortMode, BlendState blendState, SamplerState samplerState, DepthStencilState depthStencilState, RasterizerState rasterizerState, Effect effect, Matrix transformMatrix)
+        {
+            base.Begin(sortMode, blendState, samplerState, depthStencilState, rasterizerState, effect, transformMatrix);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/StardewModdingAPI/Constants.cs b/src/StardewModdingAPI/Constants.cs
index 4f2f00a1..815e5427 100644
--- a/src/StardewModdingAPI/Constants.cs
+++ b/src/StardewModdingAPI/Constants.cs
@@ -4,6 +4,7 @@ using System.IO;
 using System.Linq;
 using System.Reflection;
 using StardewModdingAPI.AssemblyRewriters;
+using StardewModdingAPI.AssemblyRewriters.Rewriters;
 using StardewValley;
 
 namespace StardewModdingAPI
@@ -116,7 +117,10 @@ namespace StardewModdingAPI
         /// <summary>Get method rewriters which fix incompatible method calls in mod assemblies.</summary>
         internal static IEnumerable<IMethodRewriter> GetMethodRewriters()
         {
-            yield break;
+            return new[]
+            {
+                new SpriteBatchRewriter()
+            };
         }