wehub-resource-sync
110 lines
3.7 KiB
C#
110 lines
3.7 KiB
C#
/*
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* QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
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* Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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using System;
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namespace QuantConnect.Util
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{
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/// <summary>
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/// Represents a read-only reference to any value, T
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/// </summary>
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/// <typeparam name="T">The data type the reference points to</typeparam>
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public interface IReadOnlyRef<out T>
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{
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/// <summary>
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/// Gets the current value this reference points to
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/// </summary>
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T Value { get; }
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}
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/// <summary>
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/// Represents a reference to any value, T
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/// </summary>
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/// <typeparam name="T">The data type the reference points to</typeparam>
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public sealed class Ref<T> : IReadOnlyRef<T>
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{
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private readonly Func<T> _getter;
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private readonly Action<T> _setter;
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/// <summary>
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/// Initializes a new instance of the <see cref="Ref{T}"/> class
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/// </summary>
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/// <param name="getter">A function delegate to get the current value</param>
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/// <param name="setter">A function delegate to set the current value</param>
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public Ref(Func<T> getter, Action<T> setter)
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{
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_getter = getter;
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_setter = setter;
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}
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/// <summary>
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/// Gets or sets the value of this reference
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/// </summary>
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public T Value
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{
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get { return _getter(); }
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set { _setter(value); }
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}
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/// <summary>
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/// Returns a read-only version of this instance
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/// </summary>
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/// <returns>A new instance with read-only semantics/gaurantees</returns>
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public IReadOnlyRef<T> AsReadOnly()
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{
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return new Ref<T>(_getter, value =>
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{
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throw new InvalidOperationException("This instance is read-only.");
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});
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}
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}
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/// <summary>
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/// Provides some helper methods that leverage C# type inference
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/// </summary>
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public static class Ref
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{
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/// <summary>
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/// Creates a new <see cref="Ref{T}"/> instance
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/// </summary>
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public static Ref<T> Create<T>(Func<T> getter, Action<T> setter)
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{
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return new Ref<T>(getter, setter);
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}
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/// <summary>
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/// Creates a new <see cref="IReadOnlyRef{T}"/> instance
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/// </summary>
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public static IReadOnlyRef<T> CreateReadOnly<T>(Func<T> getter)
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{
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return new Ref<T>(getter, value =>
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{
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throw new InvalidOperationException("This instance is read-only.");
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});
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}
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/// <summary>
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/// Creates a new <see cref="Ref{T}"/> instance by closing over
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/// the specified <paramref name="initialValue"/> variable.
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/// NOTE: This won't close over the variable input to the function,
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/// but rather a copy of the variable. This reference will use it's
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/// own storage.
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/// </summary>
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public static Ref<T> Create<T>(T initialValue)
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{
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return new Ref<T>(() => initialValue, value => { initialValue = value; });
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}
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}
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}
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