simplify CIL rewriter hierarchy

3 files changed, 25 insertions, 28 deletions

diff --git a/src/StardewModdingAPI.AssemblyRewriters/Finders/EventFinder.cs b/src/StardewModdingAPI.AssemblyRewriters/Finders/EventFinder.cs
index 359ca63e..9d0184c6 100644
--- a/src/StardewModdingAPI.AssemblyRewriters/Finders/EventFinder.cs
+++ b/src/StardewModdingAPI.AssemblyRewriters/Finders/EventFinder.cs
@@ -1,11 +1,10 @@
 using Mono.Cecil;
 using Mono.Cecil.Cil;
-using StardewModdingAPI.AssemblyRewriters.Framework;
 
 namespace StardewModdingAPI.AssemblyRewriters.Finders
 {
     /// <summary>Finds CIL instructions that reference a given event.</summary>
-    public sealed class EventFinder : BaseMethodFinder
+    public sealed class EventFinder : IInstructionFinder
     {
         /*********
         ** Properties
@@ -21,7 +20,7 @@ namespace StardewModdingAPI.AssemblyRewriters.Finders
         ** Accessors
         *********/
         /// <summary>A brief noun phrase indicating what the instruction finder matches.</summary>
-        public override string NounPhrase { get; }
+        public string NounPhrase { get; }
 
 
         /*********
@@ -41,13 +40,15 @@ namespace StardewModdingAPI.AssemblyRewriters.Finders
         /*********
         ** Protected methods
         *********/
-        /// <summary>Get whether a method reference should be rewritten.</summary>
+        /// <summary>Get whether a CIL instruction matches.</summary>
         /// <param name="instruction">The IL instruction.</param>
-        /// <param name="methodRef">The method reference.</param>
         /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
-        protected override bool IsMatch(Instruction instruction, MethodReference methodRef, bool platformChanged)
+        public bool IsMatch(Instruction instruction, bool platformChanged)
         {
-            return methodRef.DeclaringType.FullName == this.FullTypeName
+            MethodReference methodRef = RewriteHelper.AsMethodReference(instruction);
+            return
+                methodRef != null
+                && methodRef.DeclaringType.FullName == this.FullTypeName
                 && (methodRef.Name == "add_" + this.EventName || methodRef.Name == "remove_" + this.EventName);
         }
     }
diff --git a/src/StardewModdingAPI.AssemblyRewriters/Finders/FieldFinder.cs b/src/StardewModdingAPI.AssemblyRewriters/Finders/FieldFinder.cs
index 516641f2..068119b8 100644
--- a/src/StardewModdingAPI.AssemblyRewriters/Finders/FieldFinder.cs
+++ b/src/StardewModdingAPI.AssemblyRewriters/Finders/FieldFinder.cs
@@ -1,11 +1,10 @@
 using Mono.Cecil;
 using Mono.Cecil.Cil;
-using StardewModdingAPI.AssemblyRewriters.Framework;
 
 namespace StardewModdingAPI.AssemblyRewriters.Finders
 {
     /// <summary>Finds CIL instructions that reference a given field.</summary>
-    public sealed class FieldFinder : BaseFieldFinder
+    public class FieldFinder : IInstructionFinder
     {
         /*********
         ** Properties
@@ -16,15 +15,12 @@ namespace StardewModdingAPI.AssemblyRewriters.Finders
         /// <summary>The field name for which to find references.</summary>
         private readonly string FieldName;
 
-        /// <summary>Whether the field to match is static.</summary>
-        private readonly bool IsStatic;
-
 
         /*********
         ** Accessors
         *********/
         /// <summary>A brief noun phrase indicating what the instruction finder matches.</summary>
-        public override string NounPhrase { get; }
+        public string NounPhrase { get; }
 
 
         /*********
@@ -33,27 +29,26 @@ namespace StardewModdingAPI.AssemblyRewriters.Finders
         /// <summary>Construct an instance.</summary>
         /// <param name="fullTypeName">The full type name for which to find references.</param>
         /// <param name="fieldName">The field name for which to find references.</param>
-        /// <param name="isStatic">Whether the field to match is static.</param>
-        public FieldFinder(string fullTypeName, string fieldName, bool isStatic)
+        /// <param name="nounPhrase">A brief noun phrase indicating what the instruction finder matches (or <c>null</c> to generate one).</param>
+        public FieldFinder(string fullTypeName, string fieldName, string nounPhrase = null)
         {
             this.FullTypeName = fullTypeName;
             this.FieldName = fieldName;
-            this.IsStatic = isStatic;
-            this.NounPhrase = $"obsolete {fullTypeName}.{fieldName} field";
+            this.NounPhrase = nounPhrase ?? $"{fullTypeName}.{fieldName} field";
         }
 
 
         /*********
         ** Protected methods
         *********/
-        /// <summary>Get whether a field reference should be rewritten.</summary>
+        /// <summary>Get whether a CIL instruction matches.</summary>
         /// <param name="instruction">The IL instruction.</param>
-        /// <param name="fieldRef">The field reference.</param>
         /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
-        protected override bool IsMatch(Instruction instruction, FieldReference fieldRef, bool platformChanged)
+        public bool IsMatch(Instruction instruction, bool platformChanged)
         {
+            FieldReference fieldRef = RewriteHelper.AsFieldReference(instruction);
             return
-                this.IsStaticField(instruction) == this.IsStatic
+                fieldRef != null
                 && fieldRef.DeclaringType.FullName == this.FullTypeName
                 && fieldRef.Name == this.FieldName;
         }
diff --git a/src/StardewModdingAPI.AssemblyRewriters/Finders/MethodFinder.cs b/src/StardewModdingAPI.AssemblyRewriters/Finders/MethodFinder.cs
index 6c210d68..bea549ee 100644
--- a/src/StardewModdingAPI.AssemblyRewriters/Finders/MethodFinder.cs
+++ b/src/StardewModdingAPI.AssemblyRewriters/Finders/MethodFinder.cs
@@ -1,11 +1,10 @@
 using Mono.Cecil;
 using Mono.Cecil.Cil;
-using StardewModdingAPI.AssemblyRewriters.Framework;
 
 namespace StardewModdingAPI.AssemblyRewriters.Finders
 {
     /// <summary>Finds CIL instructions that reference a given method.</summary>
-    public sealed class MethodFinder : BaseMethodFinder
+    public class MethodFinder : IInstructionFinder
     {
         /*********
         ** Properties
@@ -21,7 +20,7 @@ namespace StardewModdingAPI.AssemblyRewriters.Finders
         ** Accessors
         *********/
         /// <summary>A brief noun phrase indicating what the instruction finder matches.</summary>
-        public override string NounPhrase { get; }
+        public string NounPhrase { get; }
 
 
         /*********
@@ -41,13 +40,15 @@ namespace StardewModdingAPI.AssemblyRewriters.Finders
         /*********
         ** Protected methods
         *********/
-        /// <summary>Get whether a method reference should be rewritten.</summary>
+        /// <summary>Get whether a CIL instruction matches.</summary>
         /// <param name="instruction">The IL instruction.</param>
-        /// <param name="methodRef">The method reference.</param>
         /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
-        protected override bool IsMatch(Instruction instruction, MethodReference methodRef, bool platformChanged)
+        public bool IsMatch(Instruction instruction, bool platformChanged)
         {
-            return methodRef.DeclaringType.FullName == this.FullTypeName
+            MethodReference methodRef = RewriteHelper.AsMethodReference(instruction);
+            return
+                methodRef != null
+                && methodRef.DeclaringType.FullName == this.FullTypeName
                 && methodRef.Name == this.MethodName;
         }
     }