/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Microsoft Public License. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Microsoft Public License, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Microsoft Public License.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Collections.Generic;
using System.Reflection;
using System.Reflection.Emit;
using System.Threading;
using Microsoft.Scripting.Utils;
namespace Microsoft.Scripting.Generation{
internal static partial class DelegateHelpers {
private static Dictionary<ICollection<Type>, Type> _DelegateTypes;
private static Type MakeCustomDelegate(Type[] types) {
if (_DelegateTypes == null) {
Interlocked.CompareExchange(
ref _DelegateTypes,
new Dictionary<ICollection<Type>, Type>(ListEqualityComparer<Type>.Instance),
null
);
}
bool found;
Type type;
//
// LOCK to retrieve the delegate type, if any
//
lock (_DelegateTypes) {
found = _DelegateTypes.TryGetValue(types, out type);
}
if (!found && type != null) {
return type;
}
//
// Create new delegate type
//
type = MakeNewCustomDelegate(types);
//
// LOCK to insert new delegate into the cache. If we already have one (racing threads), use the one from the cache
//
lock (_DelegateTypes) {
Type conflict;
if (_DelegateTypes.TryGetValue(types, out conflict) && conflict != null) {
type = conflict;
} else {
_DelegateTypes[types] = type;
}
}
return type;
}
private static Type MakeNewCustomDelegate(Type[] types) {
Type returnType = types[types.Length - 1];
Type[] parameters = types.RemoveLast();
return Snippets.Shared.DefineDelegate("Delegate" + types.Length, returnType, parameters);
}
}
}
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