public Detour(MethodBase method, IntPtr to)
: this(method, DetourManager.GenerateNativeProxy(to, method))
{
}
public Hook(MethodBase method, IntPtr to)
: this(method, DetourManager.GenerateNativeProxy(to, method), null)
{
}
/// <summary>
/// Generate a new DynamicMethod with which you can invoke the previous state.
/// If the NativeDetour holds a reference to a managed method, a copy of the original method is returned.
/// If the NativeDetour holds a reference to a native function, an "undo-call-redo" trampoline with a matching signature is returned.
/// </summary>
public MethodBase GenerateTrampoline(MethodBase signature = null)
{
if (_IsFree)
{
throw new InvalidOperationException("Free() has been called on this detour.");
}
if (_BackupMethod != null)
{
// If we're detouring an IL method and have an IL copy, invoke the IL copy.
// Note that this ignores the passed signature.
return(_BackupMethod);
}
if (signature == null)
{
signature = _BackupMethod;
}
if (signature == null)
{
throw new ArgumentNullException("A signature must be given if the NativeDetour doesn't hold a reference to a managed method.");
}
// Otherwise, undo the detour, call the method and reapply the detour.
MethodBase methodCallable = Method;
if (methodCallable == null)
{
methodCallable = DetourManager.GenerateNativeProxy(Data.Method, signature);
}
Type returnType = (signature as MethodInfo)?.ReturnType ?? typeof(void);
ParameterInfo[] args = signature.GetParameters();
Type[] argTypes = new Type[args.Length];
for (int i = 0; i < args.Length; i++)
{
argTypes[i] = args[i].ParameterType;
}
DynamicMethod dm;
string name = $"trampoline_native_{Method?.Name.ToString() ?? ((long) Data.Method).ToString("X16")}_{GetHashCode()}";
if (Method != null)
{
dm = new DynamicMethod(
name,
returnType, argTypes,
Method.DeclaringType,
true
);
}
else
{
dm = new DynamicMethod(
name,
returnType, argTypes,
true
);
}
ILGenerator il = dm.GetILGenerator();
il.EmitDetourCopy(_BackupNative, Data.Method, Data.Size);
// Store the return value in a local as we can't preserve the stack across exception block boundaries.
LocalBuilder localResult = null;
if (returnType != typeof(void))
{
localResult = il.DeclareLocal(returnType);
}
Label blockTry = il.BeginExceptionBlock();
// TODO: Use specialized Ldarg.* if possible; What about ref types?
for (int i = 0; i < argTypes.Length; i++)
{
il.Emit(OpCodes.Ldarg, i);
}
if (methodCallable is MethodInfo)
{
il.Emit(OpCodes.Call, (MethodInfo)methodCallable);
}
else if (methodCallable is ConstructorInfo)
{
il.Emit(OpCodes.Call, (ConstructorInfo)methodCallable);
}
else
{
throw new NotSupportedException($"Method type {methodCallable.GetType().FullName} not supported.");
}
if (localResult != null)
{
il.Emit(OpCodes.Stloc_0);
}
il.BeginFinallyBlock();
// Reapply the detour even if the method threw an exception.
il.EmitDetourApply(Data);
il.EndExceptionBlock();
if (localResult != null)
{
il.Emit(OpCodes.Ldloc_0);
}
il.Emit(OpCodes.Ret);
return(dm.Pin());
}
