generalise CIL rewriters for reuse (#231)

2 files changed, 106 insertions, 17 deletions

diff --git a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/BaseMethodRewriter.cs b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/BaseMethodRewriter.cs
index 1af6e6c4..e44acaf9 100644
--- a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/BaseMethodRewriter.cs
+++ b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/BaseMethodRewriter.cs
@@ -7,27 +7,52 @@ using Mono.Cecil.Cil;
 namespace StardewModdingAPI.AssemblyRewriters.Rewriters
 {
     /// <summary>Base class for a method rewriter.</summary>
-    public abstract class BaseMethodRewriter : IMethodRewriter
+    public abstract class BaseMethodRewriter : IInstructionRewriter
     {
         /*********
         ** 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>Get whether a CIL instruction should be rewritten.</summary>
+        /// <param name="instruction">The IL instruction.</param>
+        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
+        public bool ShouldRewrite(Instruction instruction, bool platformChanged)
+        {
+            // ignore non-method-call instructions
+            if (instruction.OpCode != OpCodes.Call && instruction.OpCode != OpCodes.Callvirt)
+                return false;
 
-        /// <summary>Rewrite a method for compatibility.</summary>
+            // check reference
+            MethodReference methodRef = (MethodReference)instruction.Operand;
+            return this.ShouldRewrite(methodRef, platformChanged);
+        }
+
+        /// <summary>Rewrite a CIL instruction 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="instruction">The instruction to rewrite.</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);
-
+        public void Rewrite(ModuleDefinition module, ILProcessor cil, Instruction instruction, PlatformAssemblyMap assemblyMap)
+        {
+            MethodReference methodRef = (MethodReference)instruction.Operand;
+            this.Rewrite(module, cil, instruction, methodRef, assemblyMap);
+        }
 
         /*********
         ** Protected methods
         *********/
+        /// <summary>Get whether the given method reference can be rewritten.</summary>
+        /// <param name="methodRef">The method reference.</param>
+        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
+        protected abstract bool ShouldRewrite(MethodReference methodRef, bool platformChanged);
+
+        /// <summary>Rewrite a method for compatibility.</summary>
+        /// <param name="module">The module being rewritten.</param>
+        /// <param name="cil">The CIL rewriter.</param>
+        /// <param name="instruction">The instruction which calls the method.</param>
+        /// <param name="methodRef">The method reference invoked by the <paramref name="instruction"/>.</param>
+        /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param>
+        protected abstract void Rewrite(ModuleDefinition module, ILProcessor cil, Instruction instruction, MethodReference methodRef, PlatformAssemblyMap assemblyMap);
+
         /// <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>
diff --git a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/SpriteBatchRewriter.cs b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/SpriteBatchRewriter.cs
index 1c0a5cf3..f64bf768 100644
--- a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/SpriteBatchRewriter.cs
+++ b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/SpriteBatchRewriter.cs
@@ -1,30 +1,94 @@
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.Xna.Framework;
 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>
+    /// <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="WrapperMethods"/>, which redirects all method signatures to the proper compiled MonoGame/XNA method.</remarks>
     public class SpriteBatchRewriter : BaseMethodRewriter
     {
+        /*********
+        ** Protected methods
+        *********/
         /// <summary>Get whether the given method reference can be rewritten.</summary>
         /// <param name="methodRef">The method reference.</param>
-        public override bool ShouldRewrite(MethodReference methodRef)
+        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
+        protected override bool ShouldRewrite(MethodReference methodRef, bool platformChanged)
         {
-            return methodRef.DeclaringType.FullName == typeof(SpriteBatch).FullName && this.HasMatchingSignature(typeof(CompatibleSpriteBatch), methodRef);
+            return platformChanged
+                && methodRef.DeclaringType.FullName == typeof(SpriteBatch).FullName
+                && this.HasMatchingSignature(typeof(SpriteBatchRewriter.WrapperMethods), 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="instruction">The instruction which calls the method.</param>
+        /// <param name="methodRef">The method reference invoked by the <paramref name="instruction"/>.</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)
+        protected override void Rewrite(ModuleDefinition module, ILProcessor cil, Instruction instruction, MethodReference methodRef, PlatformAssemblyMap assemblyMap)
         {
-            methodRef.DeclaringType = module.Import(typeof(CompatibleSpriteBatch));
+            methodRef.DeclaringType = module.Import(typeof(SpriteBatchRewriter.WrapperMethods));
+        }
+
+
+        /*********
+        ** Wrapper methods
+        *********/
+        /// <summary>Wraps <see cref="SpriteBatch"/> methods that are incompatible when converting compiled code between MonoGame and XNA.</summary>
+        public class WrapperMethods : SpriteBatch
+        {
+            /*********
+            ** Public methods
+            *********/
+            /// <summary>Construct an instance.</summary>
+            public WrapperMethods(GraphicsDevice graphicsDevice) : base(graphicsDevice) { }
+
+
+            /****
+            ** MonoGame signatures
+            ****/
+            [SuppressMessage("ReSharper", "CS0109", Justification = "The 'new' modifier applies when compiled on Linux/Mac.")]
+            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
+            ****/
+            [SuppressMessage("ReSharper", "CS0109", Justification = "The 'new' modifier applies when compiled on Windows.")]
+            public new void Begin()
+            {
+                base.Begin();
+            }
+
+            [SuppressMessage("ReSharper", "CS0109", Justification = "The 'new' modifier applies when compiled on Windows.")]
+            public new void Begin(SpriteSortMode sortMode, BlendState blendState)
+            {
+                base.Begin(sortMode, blendState);
+            }
+
+            [SuppressMessage("ReSharper", "CS0109", Justification = "The 'new' modifier applies when compiled on Windows.")]
+            public new void Begin(SpriteSortMode sortMode, BlendState blendState, SamplerState samplerState, DepthStencilState depthStencilState, RasterizerState rasterizerState)
+            {
+                base.Begin(sortMode, blendState, samplerState, depthStencilState, rasterizerState);
+            }
+
+            [SuppressMessage("ReSharper", "CS0109", Justification = "The 'new' modifier applies when compiled on Windows.")]
+            public new void Begin(SpriteSortMode sortMode, BlendState blendState, SamplerState samplerState, DepthStencilState depthStencilState, RasterizerState rasterizerState, Effect effect)
+            {
+                base.Begin(sortMode, blendState, samplerState, depthStencilState, rasterizerState, effect);
+            }
+
+            [SuppressMessage("ReSharper", "CS0109", Justification = "The 'new' modifier applies when compiled on Windows.")]
+            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);
+            }
         }
     }
 }
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