private Expression BuildMethodCall(MethodBase method, Type type, ParameterExpression targetParameterExpression, ParameterExpression argsParameterExpression)
{
ParameterInfo[] parametersInfo = method.GetParameters();
Expression[] argsExpression;
IList<ByRefParameter> refParameterMap;
if (parametersInfo.Length == 0)
{
argsExpression = CollectionUtils.ArrayEmpty<Expression>();
refParameterMap = CollectionUtils.ArrayEmpty<ByRefParameter>();
}
else
{
argsExpression = new Expression[parametersInfo.Length];
refParameterMap = new List<ByRefParameter>();
for (int i = 0; i < parametersInfo.Length; i++)
{
ParameterInfo parameter = parametersInfo[i];
Type parameterType = parameter.ParameterType;
bool isByRef = false;
if (parameterType.IsByRef)
{
parameterType = parameterType.GetElementType();
isByRef = true;
}
Expression indexExpression = Expression.Constant(i);
Expression paramAccessorExpression = Expression.ArrayIndex(argsParameterExpression, indexExpression);
Expression argExpression = EnsureCastExpression(paramAccessorExpression, parameterType, !isByRef);
if (isByRef)
{
ParameterExpression variable = Expression.Variable(parameterType);
refParameterMap.Add(new ByRefParameter {Value = argExpression, Variable = variable, IsOut = parameter.IsOut});
argExpression = variable;
}
argsExpression[i] = argExpression;
}
}
Expression callExpression;
if (method.IsConstructor)
{
callExpression = Expression.New((ConstructorInfo)method, argsExpression);
}
else if (method.IsStatic)
{
callExpression = Expression.Call((MethodInfo)method, argsExpression);
}
else
{
Expression readParameter = EnsureCastExpression(targetParameterExpression, method.DeclaringType);
callExpression = Expression.Call(readParameter, (MethodInfo)method, argsExpression);
}
if (method is MethodInfo m)
{
if (m.ReturnType != typeof(void))
{
callExpression = EnsureCastExpression(callExpression, type);
}
else
{
callExpression = Expression.Block(callExpression, Expression.Constant(null));
}
}
else
{
callExpression = EnsureCastExpression(callExpression, type);
}
if (refParameterMap.Count > 0)
{
IList<ParameterExpression> variableExpressions = new List<ParameterExpression>();
IList<Expression> bodyExpressions = new List<Expression>();
foreach (ByRefParameter p in refParameterMap)
{
if (!p.IsOut)
{
bodyExpressions.Add(Expression.Assign(p.Variable, p.Value));
}
variableExpressions.Add(p.Variable);
}
bodyExpressions.Add(callExpression);
callExpression = Expression.Block(variableExpressions, bodyExpressions);
}
return callExpression;
}
