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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
namespace Microsoft.Extensions.Options
{
/// <summary>
/// Implementation of <see cref="IOptionsFactory{TOptions}"/>.
/// </summary>
/// <typeparam name="TOptions">The type of options being requested.</typeparam>
public class OptionsFactory<[DynamicallyAccessedMembers(Options.DynamicallyAccessedMembers)] TOptions> :
IOptionsFactory<TOptions>
where TOptions : class
{
private readonly IConfigureOptions<TOptions>[] _setups;
private readonly IPostConfigureOptions<TOptions>[] _postConfigures;
private readonly IValidateOptions<TOptions>[] _validations;
/// <summary>
/// Initializes a new instance with the specified options configurations.
/// </summary>
/// <param name="setups">The configuration actions to run.</param>
/// <param name="postConfigures">The initialization actions to run.</param>
public OptionsFactory(IEnumerable<IConfigureOptions<TOptions>> setups, IEnumerable<IPostConfigureOptions<TOptions>> postConfigures) : this(setups, postConfigures, validations: Array.Empty<IValidateOptions<TOptions>>())
{ }
/// <summary>
/// Initializes a new instance with the specified options configurations.
/// </summary>
/// <param name="setups">The configuration actions to run.</param>
/// <param name="postConfigures">The initialization actions to run.</param>
/// <param name="validations">The validations to run.</param>
public OptionsFactory(IEnumerable<IConfigureOptions<TOptions>> setups, IEnumerable<IPostConfigureOptions<TOptions>> postConfigures, IEnumerable<IValidateOptions<TOptions>> validations)
{
// The default DI container uses arrays under the covers. Take advantage of this knowledge
// by checking for an array and enumerate over that, so we don't need to allocate an enumerator.
// When it isn't already an array, convert it to one, but don't use System.Linq to avoid pulling Linq in to
// small trimmed applications.
_setups = setups as IConfigureOptions<TOptions>[] ?? new List<IConfigureOptions<TOptions>>(setups).ToArray();
_postConfigures = postConfigures as IPostConfigureOptions<TOptions>[] ?? new List<IPostConfigureOptions<TOptions>>(postConfigures).ToArray();
_validations = validations as IValidateOptions<TOptions>[] ?? new List<IValidateOptions<TOptions>>(validations).ToArray();
}
/// <summary>
/// Returns a configured <typeparamref name="TOptions"/> instance with the given <paramref name="name"/>.
/// </summary>
/// <param name="name">The name of the <typeparamref name="TOptions"/> instance to create.</param>
/// <returns>The created <typeparamref name="TOptions"/> instance with the given <paramref name="name"/>.</returns>
/// <exception cref="OptionsValidationException">One or more <see cref="IValidateOptions{TOptions}"/> return failed <see cref="ValidateOptionsResult"/> when validating the <typeparamref name="TOptions"/> instance created.</exception>
/// <exception cref="MissingMethodException">The <typeparamref name="TOptions"/> does not have a public parameterless constructor or <typeparamref name="TOptions"/> is <see langword="abstract"/>.</exception>
public TOptions Create(string name)
{
TOptions options = CreateInstance(name);
foreach (IConfigureOptions<TOptions> setup in _setups)
{
if (setup is IConfigureNamedOptions<TOptions> namedSetup)
{
namedSetup.Configure(name, options);
}
else if (name == Options.DefaultName)
{
setup.Configure(options);
}
}
foreach (IPostConfigureOptions<TOptions> post in _postConfigures)
{
post.PostConfigure(name, options);
}
if (_validations.Length > 0)
{
var failures = new List<string>();
foreach (IValidateOptions<TOptions> validate in _validations)
{
ValidateOptionsResult result = validate.Validate(name, options);
if (result is not null && result.Failed)
{
failures.AddRange(result.Failures);
}
}
if (failures.Count > 0)
{
throw new OptionsValidationException(name, typeof(TOptions), failures);
}
}
return options;
}
/// <summary>
/// Creates a new instance of type <typeparamref name="TOptions"/>.
/// </summary>
/// <param name="name">The name of the <typeparamref name="TOptions"/> instance to create.</param>
/// <returns>The created <typeparamref name="TOptions"/> instance.</returns>
/// <exception cref="MissingMethodException">The <typeparamref name="TOptions"/> does not have a public parameterless constructor or <typeparamref name="TOptions"/> is <see langword="abstract"/>.</exception>
protected virtual TOptions CreateInstance(string name)
{
return Activator.CreateInstance<TOptions>();
}
}
}
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