using System; using Mono.Cecil; using Mono.Cecil.Cil; namespace StardewModdingAPI.Framework.ModLoading.Rewriters { /// <summary>Rewrites method references from one parent type to another if the signatures match.</summary> internal class MethodParentRewriter : IInstructionHandler { /********* ** Properties *********/ /// <summary>The type whose methods to remap.</summary> private readonly Type FromType; /// <summary>The type with methods to map to.</summary> private readonly Type ToType; /// <summary>Whether to only rewrite references if loading the assembly on a different platform than it was compiled on.</summary> private readonly bool OnlyIfPlatformChanged; /********* ** Accessors *********/ /// <summary>A brief noun phrase indicating what the instruction finder matches.</summary> public string NounPhrase { get; } /********* ** Public methods *********/ /// <summary>Construct an instance.</summary> /// <param name="fromType">The type whose methods to remap.</param> /// <param name="toType">The type with methods to map to.</param> /// <param name="onlyIfPlatformChanged">Whether to only rewrite references if loading the assembly on a different platform than it was compiled on.</param> public MethodParentRewriter(Type fromType, Type toType, bool onlyIfPlatformChanged = false) { this.FromType = fromType; this.ToType = toType; this.NounPhrase = $"{fromType.Name} methods"; this.OnlyIfPlatformChanged = onlyIfPlatformChanged; } /// <summary>Perform the predefined logic for a method if applicable.</summary> /// <param name="module">The assembly module containing the instruction.</param> /// <param name="method">The method definition containing the instruction.</param> /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param> /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param> public InstructionHandleResult Handle(ModuleDefinition module, MethodDefinition method, PlatformAssemblyMap assemblyMap, bool platformChanged) { return InstructionHandleResult.None; } /// <summary>Perform the predefined logic for an instruction if applicable.</summary> /// <param name="module">The assembly module containing the instruction.</param> /// <param name="cil">The CIL processor.</param> /// <param name="instruction">The instruction to handle.</param> /// <param name="assemblyMap">Metadata for mapping assemblies to the current platform.</param> /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param> public InstructionHandleResult Handle(ModuleDefinition module, ILProcessor cil, Instruction instruction, PlatformAssemblyMap assemblyMap, bool platformChanged) { if (!this.IsMatch(instruction, platformChanged)) return InstructionHandleResult.None; MethodReference methodRef = (MethodReference)instruction.Operand; methodRef.DeclaringType = module.Import(this.ToType); return InstructionHandleResult.Rewritten; } /********* ** Protected methods *********/ /// <summary>Get whether a CIL instruction matches.</summary> /// <param name="instruction">The IL instruction.</param> /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param> protected bool IsMatch(Instruction instruction, bool platformChanged) { MethodReference methodRef = RewriteHelper.AsMethodReference(instruction); return methodRef != null && (platformChanged || !this.OnlyIfPlatformChanged) && methodRef.DeclaringType.FullName == this.FromType.FullName && RewriteHelper.HasMatchingSignature(this.ToType, methodRef); } } }