PowerShell/src/System.Management.Automation/engine/ComInterop/SplatCallSite.cs

/********************************************************************++
Copyright (c) Microsoft Corporation.  All rights reserved.
--********************************************************************/

#if !CLR2
#else
using Microsoft.Scripting.Ast;
#endif
using System.Diagnostics;
using System.Runtime.CompilerServices;
//using Microsoft.Scripting.Utils;

#if !SILVERLIGHT
namespace System.Management.Automation.ComInterop
{
    internal sealed class SplatCallSite
    {
        // Stored callable Delegate or IDynamicMetaObjectProvider.
        internal readonly object _callable;

        // Can the number of arguments to a given event change each call?
        // If not, we don't need this level of indirection--we could cache a
        // delegate that does the splatting.
        internal CallSite<Func<CallSite, object, object[], object>> _site;

        internal SplatCallSite(object callable)
        {
            Debug.Assert(callable != null);
            _callable = callable;
        }

        internal object Invoke(object[] args)
        {
            Debug.Assert(args != null);

            // If it is a delegate, just let DynamicInvoke do the binding.
            var d = _callable as Delegate;
            if (d != null)
            {
                return d.DynamicInvoke(args);
            }

            // Otherwise, create a CallSite and invoke it.
            if (_site == null)
            {
                _site = CallSite<Func<CallSite, object, object[], object>>.Create(SplatInvokeBinder.Instance);
            }

            return _site.Target(_site, _callable, args);
        }
    }
}
#endif