merge CIL finders & rewriters into one interface (#254)

1 files changed, 15 insertions, 13 deletions

diff --git a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/FieldReplaceRewriter.cs b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/FieldReplaceRewriter.cs
index ffd22e7c..95663c49 100644
--- a/src/StardewModdingAPI.AssemblyRewriters/Rewriters/FieldReplaceRewriter.cs
+++ b/src/StardewModdingAPI.AssemblyRewriters/Rewriters/FieldReplaceRewriter.cs
@@ -7,16 +7,13 @@ using StardewModdingAPI.AssemblyRewriters.Finders;
 namespace StardewModdingAPI.AssemblyRewriters.Rewriters
 {
     /// <summary>Rewrites references to one field with another.</summary>
-    public class FieldReplaceRewriter : FieldFinder, IInstructionRewriter
+    public class FieldReplaceRewriter : FieldFinder
     {
         /*********
         ** Properties
         *********/
-        /// <summary>The type whose field to which references should be rewritten.</summary>
-        private readonly Type Type;
-
-        /// <summary>The new field name to reference.</summary>
-        private readonly string ToFieldName;
+        /// <summary>The new field to reference.</summary>
+        private readonly FieldInfo ToField;
 
 
         /*********
@@ -30,8 +27,9 @@ namespace StardewModdingAPI.AssemblyRewriters.Rewriters
         public FieldReplaceRewriter(Type type, string fromFieldName, string toFieldName, string nounPhrase = null)
             : base(type.FullName, fromFieldName, nounPhrase)
         {
-            this.Type = type;
-            this.ToFieldName = toFieldName;
+            this.ToField = type.GetField(toFieldName);
+            if (this.ToField == null)
+                throw new InvalidOperationException($"The {type.FullName} class doesn't have a {toFieldName} field.");
         }
 
         /// <summary>Rewrite a CIL instruction for compatibility.</summary>
@@ -39,13 +37,17 @@ namespace StardewModdingAPI.AssemblyRewriters.Rewriters
         /// <param name="cil">The CIL rewriter.</param>
         /// <param name="instruction">The instruction to rewrite.</param>
         /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param>
-        public void Rewrite(ModuleDefinition module, ILProcessor cil, Instruction instruction, PlatformAssemblyMap assemblyMap)
+        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
+        /// <returns>Returns whether the instruction was rewritten.</returns>
+        /// <exception cref="IncompatibleInstructionException">The CIL instruction is not compatible, and can't be rewritten.</exception>
+        public override bool Rewrite(ModuleDefinition module, ILProcessor cil, Instruction instruction, PlatformAssemblyMap assemblyMap, bool platformChanged)
         {
-            FieldInfo field = this.Type.GetField(this.ToFieldName);
-            if (field == null)
-                throw new InvalidOperationException($"The {this.Type.FullName} class doesn't have a {this.ToFieldName} field.");
-            FieldReference newRef = module.Import(field);
+            if (!this.IsMatch(instruction, platformChanged))
+                return false;
+
+            FieldReference newRef = module.Import(this.ToField);
             cil.Replace(instruction, cil.Create(instruction.OpCode, newRef));
+            return true;
         }
     }
 }