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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://github.com/jskeet/dotnet-protobufs/
// Original C++/Java/Python code:
// http://code.google.com/p/protobuf/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
using System;
using System.Collections;
using System.Collections.Generic;
namespace Google.ProtocolBuffers.Collections
{
/// <summary>
/// Proxies calls to a <see cref="List{T}" />, but allows the list
/// to be made read-only (with the <see cref="MakeReadOnly" /> method),
/// after which any modifying methods throw <see cref="NotSupportedException" />.
/// </summary>
public sealed class PopsicleList<T> : IPopsicleList<T>, ICastArray
{
private static readonly bool CheckForNull = default(T) == null;
private static readonly T[] EmptySet = new T[0];
private List<T> items;
private bool readOnly;
/// <summary>
/// Makes this list read-only ("freezes the popsicle"). From this
/// point on, mutating methods (Clear, Add etc) will throw a
/// NotSupportedException. There is no way of "defrosting" the list afterwards.
/// </summary>
public void MakeReadOnly()
{
readOnly = true;
}
public int IndexOf(T item)
{
return items == null ? -1 : items.IndexOf(item);
}
public void Insert(int index, T item)
{
ValidateModification();
if (CheckForNull)
{
ThrowHelper.ThrowIfNull(item);
}
items.Insert(index, item);
}
public void RemoveAt(int index)
{
ValidateModification();
items.RemoveAt(index);
}
public T this[int index]
{
get
{
if (items == null)
{
throw new ArgumentOutOfRangeException();
}
return items[index];
}
set
{
ValidateModification();
if (CheckForNull)
{
ThrowHelper.ThrowIfNull(value);
}
items[index] = value;
}
}
public void Add(T item)
{
ValidateModification();
if (CheckForNull)
{
ThrowHelper.ThrowIfNull(item);
}
items.Add(item);
}
public void Clear()
{
ValidateModification();
items.Clear();
}
public bool Contains(T item)
{
return items == null ? false : items.Contains(item);
}
public void CopyTo(T[] array, int arrayIndex)
{
if (items != null)
{
items.CopyTo(array, arrayIndex);
}
}
public int Count
{
get { return items == null ? 0 : items.Count; }
}
public bool IsReadOnly
{
get { return readOnly; }
}
public bool Remove(T item)
{
ValidateModification();
return items.Remove(item);
}
public IEnumerator<T> GetEnumerator()
{
IEnumerable<T> tenum = (IEnumerable<T>)items ?? EmptySet;
return tenum.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
public void Add(IEnumerable<T> collection)
{
ValidateModification();
ThrowHelper.ThrowIfNull(collection);
if (!CheckForNull || collection is PopsicleList<T>)
{
items.AddRange(collection);
}
else
{
// Assumption, it's ok to enumerate collections more than once.
if (collection is ICollection<T>)
{
ThrowHelper.ThrowIfAnyNull(collection);
items.AddRange(collection);
}
else
{
foreach (T item in collection)
{
ThrowHelper.ThrowIfNull(item);
items.Add(item);
}
}
}
}
private void ValidateModification()
{
if (readOnly)
{
throw new NotSupportedException("List is read-only");
}
if (items == null)
{
items = new List<T>();
}
}
IEnumerable<TItemType> ICastArray.CastArray<TItemType>()
{
if (items == null)
{
return PopsicleList<TItemType>.EmptySet;
}
return (TItemType[]) (object) items.ToArray();
}
}
}
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