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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
/*============================================================
**
** Interface: IReadOnlyCollection<T>
**
** <OWNER>matell</OWNER>
**
** Purpose: Base interface for read-only generic lists.
**
===========================================================*/
using System;
using System.Diagnostics.Contracts;
using System.Runtime.CompilerServices;
namespace System.Collections.Generic
{
// Provides a read-only, covariant view of a generic list.
// Note that T[] : IReadOnlyList<T>, and we want to ensure that if you use
// IList<YourValueType>, we ensure a YourValueType[] can be used
// without jitting. Hence the TypeDependencyAttribute on SZArrayHelper.
// This is a special hack internally though - see VM\compile.cpp.
// The same attribute is on IList<T>, IEnumerable<T>, ICollection<T>, and IReadOnlyList<T>.
[TypeDependencyAttribute("System.SZArrayHelper")]
#if CONTRACTS_FULL
[ContractClass(typeof(IReadOnlyCollectionContract<>))]
#endif
// If we ever implement more interfaces on IReadOnlyCollection, we should also update RuntimeTypeCache.PopulateInterfaces() in rttype.cs
public interface IReadOnlyCollection<out T> : IEnumerable<T>
{
int Count { get; }
}
#if CONTRACTS_FULL
[ContractClassFor(typeof(IReadOnlyCollection<>))]
internal abstract class IReadOnlyCollectionContract<T> : IReadOnlyCollection<T>
{
int IReadOnlyCollection<T>.Count {
get {
Contract.Ensures(Contract.Result<int>() >= 0);
return default(int);
}
}
IEnumerator<T> IEnumerable<T>.GetEnumerator()
{
return default(IEnumerator<T>);
}
IEnumerator IEnumerable.GetEnumerator()
{
return default(IEnumerator);
}
}
#endif
}
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