using System;
using Mono.Cecil;
using Mono.Cecil.Cil;
using StardewModdingAPI.Framework.ModLoading.Finders;
namespace StardewModdingAPI.Framework.ModLoading.Rewriters
{
/// Rewrites static field references into constant values.
/// The constant value type.
internal class StaticFieldToConstantRewriter : FieldFinder
{
/*********
** Properties
*********/
/// The constant value to replace with.
private readonly TValue Value;
/*********
** Public methods
*********/
/// Construct an instance.
/// The type whose field to which references should be rewritten.
/// The field name to rewrite.
/// The constant value to replace with.
public StaticFieldToConstantRewriter(Type type, string fieldName, TValue value)
: base(type.FullName, fieldName, InstructionHandleResult.None)
{
this.Value = value;
}
/// Perform the predefined logic for an instruction if applicable.
/// The assembly module containing the instruction.
/// The CIL processor.
/// The instruction to handle.
/// Metadata for mapping assemblies to the current platform.
/// Whether the mod was compiled on a different platform.
public override InstructionHandleResult Handle(ModuleDefinition module, ILProcessor cil, Instruction instruction, PlatformAssemblyMap assemblyMap, bool platformChanged)
{
if (!this.IsMatch(instruction))
return InstructionHandleResult.None;
cil.Replace(instruction, this.CreateConstantInstruction(cil, this.Value));
return InstructionHandleResult.Rewritten;
}
/*********
** Private methods
*********/
/// Create a CIL constant value instruction.
/// The CIL processor.
/// The constant value to set.
private Instruction CreateConstantInstruction(ILProcessor cil, object value)
{
if (typeof(TValue) == typeof(int))
return cil.Create(OpCodes.Ldc_I4, (int)value);
if (typeof(TValue) == typeof(string))
return cil.Create(OpCodes.Ldstr, (string)value);
throw new NotSupportedException($"Rewriting to constant values of type {typeof(TValue)} isn't currently supported.");
}
}
}