private static MethodInfo GetPatchMethod <T>(T action) where T : Delegate
{
if (action.Method.IsStatic && action.Target == null)
{
return(action.Method);
}
if (MethodCache.TryGetValue(action, out var method))
{
return(method);
}
var actionParams = action.Method.GetParameters();
var dmd = new DynamicMethodDefinition($"ActionWrapper_{action.Method.Name}", action.Method.ReturnType,
actionParams.Select(p => p.ParameterType).ToArray());
for (var i = 0; i < dmd.Definition.Parameters.Count; i++)
{
var paramInfo = actionParams[i];
var paramDef = dmd.Definition.Parameters[i];
paramDef.Name = paramInfo.Name;
}
var il = dmd.GetILGenerator();
var preserveCtx = action.Target != null && action.Target.GetType().GetFields().Any(x => !x.IsStatic);
if (preserveCtx)
{
var currentCounter = delegateCounter++;
DelegateCache[currentCounter] = action;
var cacheField = AccessTools.Field(typeof(HarmonyDelegatePatchingExtensions), nameof(DelegateCache));
var getMethod = AccessTools.Method(typeof(Dictionary <int, Delegate>), "get_Item");
il.Emit(OpCodes.Ldsfld, cacheField);
il.Emit(OpCodes.Ldc_I4, currentCounter);
il.Emit(OpCodes.Callvirt, getMethod);
}
else
{
if (action.Target == null)
{
il.Emit(OpCodes.Ldnull);
}
else
{
il.Emit(OpCodes.Newobj,
AccessTools.FirstConstructor(action.Target.GetType(),
x => x.GetParameters().Length == 0 && !x.IsStatic));
}
il.Emit(OpCodes.Ldftn, action.Method);
il.Emit(OpCodes.Newobj, AccessTools.Constructor(typeof(T), new[] { typeof(object), typeof(IntPtr) }));
}
for (var i = 0; i < actionParams.Length; i++)
{
il.Emit(OpCodes.Ldarg_S, (short)i);
}
il.Emit(OpCodes.Callvirt, AccessTools.Method(typeof(T), "Invoke"));
il.Emit(OpCodes.Ret);
// Generate with cecil to ensure it's usable with Harmony (Harmony blocks DynamicMethods by default)
var result = DMDGenerator <DMDCecilGenerator> .Generate(dmd);
MethodCache[action] = result;
return(result);
}
public static MethodInfo GenerateWith <T>(this DynamicMethodDefinition dmd, object context = null)
where T : DMDGenerator <T>, new()
{
return(DMDGenerator <T> .Generate(dmd, context));
}