merge field rewriters to reduce rewrite iterations

1 files changed, 28 insertions, 26 deletions

diff --git a/src/SMAPI/Framework/ModLoading/Rewriters/FieldReplaceRewriter.cs b/src/SMAPI/Framework/ModLoading/Rewriters/FieldReplaceRewriter.cs
index 0b679e9d..857a2230 100644
--- a/src/SMAPI/Framework/ModLoading/Rewriters/FieldReplaceRewriter.cs
+++ b/src/SMAPI/Framework/ModLoading/Rewriters/FieldReplaceRewriter.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Reflection;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
@@ -12,54 +13,55 @@ namespace StardewModdingAPI.Framework.ModLoading.Rewriters
         /*********
         ** Fields
         *********/
-        /// <summary>The type containing the field to which references should be rewritten.</summary>
-        private readonly Type Type;
-
-        /// <summary>The field name to which references should be rewritten.</summary>
-        private readonly string FromFieldName;
-
-        /// <summary>The new field to reference.</summary>
-        private readonly FieldInfo ToField;
+        /// <summary>The new fields to reference indexed by the old field/type names.</summary>
+        private readonly Dictionary<string, Dictionary<string, FieldInfo>> FieldMaps = new();
 
 
         /*********
         ** Public methods
         *********/
         /// <summary>Construct an instance.</summary>
+        public FieldReplaceRewriter()
+            : base(defaultPhrase: "field replacement") { } // will be overridden when a field is replaced
+
+        /// <summary>Add a field to replace.</summary>
         /// <param name="fromType">The type whose field to rewrite.</param>
         /// <param name="fromFieldName">The field name to rewrite.</param>
         /// <param name="toType">The new type which will have the field.</param>
         /// <param name="toFieldName">The new field name to reference.</param>
-        public FieldReplaceRewriter(Type fromType, string fromFieldName, Type toType, string toFieldName)
-            : base(defaultPhrase: $"{fromType.FullName}.{fromFieldName} field")
+        public FieldReplaceRewriter AddField(Type fromType, string fromFieldName, Type toType, string toFieldName)
         {
-            this.Type = fromType;
-            this.FromFieldName = fromFieldName;
-            this.ToField = toType.GetField(toFieldName);
-            if (this.ToField == null)
+            // get full type name
+            string fromTypeName = fromType?.FullName;
+            if (fromTypeName == null)
+                throw new InvalidOperationException($"Can't replace field for invalid type reference {toType}.");
+
+            // get target field
+            FieldInfo toField = toType.GetField(toFieldName);
+            if (toField == null)
                 throw new InvalidOperationException($"The {toType.FullName} class doesn't have a {toFieldName} field.");
-        }
 
-        /// <summary>Construct an instance.</summary>
-        /// <param name="type">The type whose field to rewrite.</param>
-        /// <param name="fromFieldName">The field name to rewrite.</param>
-        /// <param name="toFieldName">The new field name to reference.</param>
-        public FieldReplaceRewriter(Type type, string fromFieldName, string toFieldName)
-            : this(type, fromFieldName, type, toFieldName)
-        {
+            // add mapping
+            if (!this.FieldMaps.TryGetValue(fromTypeName, out var fieldMap))
+                this.FieldMaps[fromTypeName] = fieldMap = new();
+            fieldMap[fromFieldName] = toField;
+
+            return this;
         }
 
         /// <inheritdoc />
         public override bool Handle(ModuleDefinition module, ILProcessor cil, Instruction instruction)
         {
-            // get field reference
             FieldReference fieldRef = RewriteHelper.AsFieldReference(instruction);
-            if (!RewriteHelper.IsFieldReferenceTo(fieldRef, this.Type.FullName, this.FromFieldName))
+            string declaringType = fieldRef?.DeclaringType?.FullName;
+
+            // get mapped field
+            if (declaringType == null || !this.FieldMaps.TryGetValue(declaringType, out var fieldMap) || !fieldMap.TryGetValue(fieldRef.Name, out FieldInfo toField))
                 return false;
 
             // replace with new field
-            instruction.Operand = module.ImportReference(this.ToField);
-
+            this.Phrases.Add($"{fieldRef.DeclaringType.Name}.{fieldRef.Name} field");
+            instruction.Operand = module.ImportReference(toField);
             return this.MarkRewritten();
         }
     }