99 lines
3.1 KiB
C#
99 lines
3.1 KiB
C#
/*
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* Copyright (c) Microsoft Corporation
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* All rights reserved.
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*
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* - Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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* - Neither the name of the openmetaverse.co nor the names
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* of its contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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using System;
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using System.Threading;
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namespace OpenMetaverse
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{
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public class Lazy<T>
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{
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private T _value = default(T);
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private volatile bool _isValueCreated = false;
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private Func<T> _valueFactory = null;
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private readonly object _lock;
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public bool IsValueCreated => _isValueCreated;
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public Lazy()
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: this(Activator.CreateInstance<T>)
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{
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}
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public Lazy(bool isThreadSafe)
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: this(Activator.CreateInstance<T>, isThreadSafe)
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{
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}
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public Lazy(Func<T> valueFactory) :
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this(valueFactory, true)
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{
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}
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public Lazy(Func<T> valueFactory, bool isThreadSafe)
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{
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if (isThreadSafe)
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{
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_lock = new object();
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}
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_valueFactory = valueFactory;
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}
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public T Value
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{
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get
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{
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if (!_isValueCreated)
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{
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if (_lock != null)
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{
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Monitor.Enter(this._lock);
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}
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try
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{
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var value = _valueFactory.Invoke();
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_valueFactory = null;
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Thread.MemoryBarrier();
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_value = value;
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_isValueCreated = true;
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}
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finally
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{
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if (_lock != null)
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{
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Monitor.Exit(_lock);
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}
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}
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}
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return _value;
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}
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}
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}
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}
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